5291 5295.output

* GB785698 (A)

Description: GB785698 (A) ? 1957-11-06

Improvements in the interior linings of containers

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The EPO does not accept any responsibility for the accuracy of data and information originating from other authorities than the EPO; in particular, the EPO does not guarantee that they are complete, up-to-date or fit for specific purposes.

PATENT SPECIFICATION Date of Application and filing Complete Specification: July 9, 1953. 785,698 No 32471153. Application made in United States of America on July 19, 1952. (Divided out of No 785,693) Complete Specification Published: Nov 6, 1957. Index at acceptance:-Classes 69 ( 1), J 3 A; 82 ( 2), F( 1 B 1 B:2 U:2 Z 6), F 4 (A:E:F:C:J:K: W); and 103 ( 4), L 2 A 4 F. International Classification:-B 61 d, B 65 d, C 23 c. COMPLETE SPECIFICATION Improvements in the Interior Linings of Containers We, GENERAL AMERICAN TRANSPORTATION CORPORATION, a Corporation organised under the Laws of the State of New York, United States of America, of 135 South La Salle Street, City of Chicago, State of Illinois, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:The present invention relates to containers, such as shipping containers, storage tanks and railway tank cars, having interior linings formed principally of nickel. Heretofore it has not been commercially practical to produce large

shipping or storage containers or tanks having satisfactory interior linings formed principally of nickel due to the great expense involved in employing nickel-clad steel sheet in the manufacture thereof In railway tank cars having interiors of nickel-clad steel, about the thinnest nickel coating that may be employed has a thickness of 125 mils, which is greatly in excess of the thickness of nickel required for commercial use. Moreover, nickel-clad steel interior linings 6 f large containers, such as railway tank cars, are objectionable because such linings have many cracks and crevices and are not satisfactory for storing or shipping certain foods, such as milk and wine, since such material accumulates in the cracks and crevices and as a result, it is virtually impossible to clean the container or tank car after use. The foregoing disadvantages are overcome by the present invention which now provides a container formed of a catalytic material and provided with a smooth, continuous and substantially homogeneous lining intimately bonded to the interior surface thereof and comprising an alloy of nickel and phosphorus containing 3 to 1 % phosphorus by weight The container normally comprises lPrice 3/Aice 4 S 6 t a wall defined by one or more sheets of a catalytic material securely joined together at the meeting edges thereof, e g, by welded joints, and a smooth continuous seamless and substantially homogeneous layer of solid 50 material intimately bonded to the interior surfaces of both said one or more sheets and said one or more joints therebetween and in covering relation therewith, the material of said layer comprising an alloy consisting of 55 89 to 97 % nickel and 3 to 11 % phosphorus by weight, said layer constituting a liner for said wall and characterized by adhesion, wear resistance and resistance to corrosive attack by acids and bases, comparable to electro 60 deposited nickel. The smooth, continuous, seamless, and substantially homogeneous layer of solid material provided on the interior of the container of the present invention has a thickness 65 of 1 to 5 mils and comprises an alloy consisting of 89 to 97 % nickel and 3 to 11 % phosphorus by weight. In accordance with the present invention, there is no stratification of the layer of nickel 70 phosphorus upon the interior surface of the container and the nickel-phosphorus lining is smooth, continuous and substantially homogeneous and devoid of cracks and crevices Accordingly, the containers of the 75 present invention are entirely satisfactory for the shipment of foods of the type mentioned above, because the interior lining may be readily and thoroughly cleaned in a simple manner after use 80 Although generally speaking, a shipping container, storage tank or railway tank car -would be formed of steel,

it should be noted that any of these containers may be formed of any suitable catalytic material In this 85 connection, it is noted that the following elements are catalytic materials and may be readily nickel plated: copper, silver, gold, beryllium, boron, germanium, aluminium, thallium, silicon, carbon, vanadium, molyb 90 785,698 denum, tungsten, chromium, selenium, tellurium, titanium, iron, cobalt, nickel, palladium and platinum; whereas the following elements are non-catalytic and may not be nickel plated: bismuth, cadmium, tin, lead and manganese Of the catalytic elements noted, the following are particularly good materials: aluminium, carbon, chromium, cobalt, iron, nickel and palladium Also such non-conductors as vitreous, ceramic and plastic materials, may not be directly nickel plated. The nickel-phosphorus lining may be formed on the interior of the container of the present invention by the chemical nickel plating technique which employs a plating solution of the nickel cation-hypophosphite anion type such as forms the subject matter of our Co-pending Applications Nos 172061 53 (Serial No 761062), 19063 j 53 and 32470/55 (Serial Nos 785,693 and 785,697). The continuous process and the apparatus disclosed in Application No 32470/55 (Serial No 785,697) is particularly suitable for the commercial production of the containers of the present invention, especially large containers such as railway tank cars In this connection, it will be understood that alloys of the catalytic elements mentioned hereinabove may be plated, and that the chemical nickel plating reaction, such as is involved in the method and apparatus of our co-pending applications, is autocatalytic so that once it is initiated it proceeds automatically. Although the linings of the containers of the present invention are composed fundamentally of nickel, the linings include from 3 to 11 % phosphorus as noted above This circumstance is advantageous in that the lining is considerably harder than a corresponding pure nickel lining, such as produced by electrodeposition On the other hand, the lining of this invention is characterized by adhesion, wear resistance and resistance to corrosive attack by acids and bases comparable to electrodeposited nickel Furthermore, because the chemical nickel plating reaction is autocatalytic and the plating solution may be manipulated so as to prevent any material variation in the standard composition thereof, the plating reaction may be carried on for any suitable length of time in order to obtain any appropriate and desired thickness of the nickel-phosphorus lining. In the above description and the appended claims the term catalytic material " means any material which can be nickel-plated in an aqueous bath of the nickel cation-hypophosphite anion type with the evolution of 69 hydrogen gas at the catalytic surface, and includes a material

comprising an element which is catalytic for the oxidation of hypophosphite ions, and materials comprising an element which may be nickel-plated by virtue of the initial displacement deposition of nickel thereon either directly or through a galvanic effect.

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* GB785699 (A)

Description: GB785699 (A) ? 1957-11-06

Improvements in or relating to domestic fires

Description of GB785699 (A)

PATENT SPECIFICATION 785,699 Date of filing Complete Specification: Oct 26, 1954, Application Date: Oct 26, 1953. No 29554/53. Complete Specification Published: Nov 6, 1957. Index at acceptance:-Class 64 ( 3), 524 C. International Classification:-F 25 h. COMPLETE SPECIFICATION - Improvements in or relating to Domestic 'Fires We, B FI Nc H & 'COMPANY LIMITED, a British Company, of Belvedere Worksh, Sherwood Road, Barkingside, Essex, STANLEY ERNEST THROWER, a British Subject, of 327, Stradbroke Grove, Ilford, Essex, and JACK BUTLER, a British Subject, of 5, Milkwell' Gardens, Woodford Green, Essex, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention is 'concerned with, domestic fires, More particulary, it relate S to a domestic open fire of the kind wherein air is drawn

through an intake or intakes substantially at hearth level into a duct or ducts, is led by said duct or ducts into a horizontal air chan' ber across the top of the fire opening and constituting the front of the fireplace throat through which the combustion gases escape to the flue, and is delivered from said air chamber into the room being heated through an outlet or outlets in the front of the chamber. According to the present invention there is provided a fireplace front, for a domestic open fire of the kind described, which comprises the aforesaid horizontal air chamber across the top of the fire opening, and wherein an internal baffle is provided in the air chamber and the air from the aforesaid duct or ducts, or most of it, enters the chamber on the opposite side of the baffle, to that where the outlet or outletsl are situated, the baffle being so disposed that the air is forced to flow over the rear wall of the chamber (which constitutes the front wall of the fireplace throat) on its way to said outlet or outlets. The invention also provides a domestic open fire of the kind described, wherein an internal baffle is provided in the aforesaid' air chamber extending from the front wall thereof toward but not reaching the rear wall (which constitutes the front wall of the fireplace throat), and the air from the aforesaid duct or ducts enters the chamber on the opposite side of the baffle to that where the outlet or outlets lPrice 3 s 6 d l are situated so that the air is' forced to flow over the rear wall of the chamber on its way to said outlet or outlets: The following is a description 'by way of example of a fireplace front in accordance with the invention, reference being made to the accompanying drawings, in which: Figure 1 is a perspective view of ithe fireplace front; Figure 2 is an upright cross-sectional view of a idomestic fire using the fireplace front; and Figure 3 is a horizontal cross-sectional view of a domestic fire using the fireplace front. The fireplace front comprises a long horizontal heat-exchange chamber 10 of cast iron or steel, providing the front wall of a smoke chamber 11 of a domestic open fire as described in our co-pending application No. 295,96/53 ' (Serial No, 785,700 The heat-exchange chamber 10 has a flat horizontal top wall and a flat vertical front wall at right angles to each other and of substantially the same width (i e the same dimension transverse to the length of the heat-exchangechamber) The front wall is curved rearwardly and then upwardly at its lower edge to provide a portion of semi-circular cross-section having a horizontal diameter which is substantially half the width of the top wall From the semi-circular portion, a rear wall of the heat-exchange chamber curves upwardly and rearwardly in a concave manner for most of its

height; towards its top, the rear wall curves' into a short convex portion which meets the top' wall, (This shaping is most clearly seen in Figure 2) The ends of the heat-exchange chamber above the level of a baffle therein (described hereinafter) are closed 'by flat vertical end wall's 13 The heat-exchange chamber 10 extends across and defines the top of the fire-opening, and said semi-circular lower portion provides the front wall of the throat 12 of the lire, while the rear wall extending upwardly therefrom provides the front wall;of the smoke 2 785,699 chamber 11, leading upwardly and rearwardly to the flue so that the combustion products pass over it The chamber 10 is also heated by radiant heat from the fire Two vertical rectangular ducts 14 are provided opening at their upper ends into the ends of the semi-circular bottom of the heatexchange chamber Conveniently, as shown in the drawings, the ducts are provided by upright shallow troughlike members which cooperate with a wall 16 of the fireplace structure to provide said ducts The vertical ducts are arranged to lie against the sides of the fire-back 15 so as to be heated thereby Air is admitted to the ducts 14 through gaps which are left between them and the wall 16. A narrow horizontal aperture 17 extends for the whole length of the front wall of the heatexchange chamber 10 adjacent the top thereof, so that heated air can emerge into the room Also extending for the whole length of the heat-exchange chamber is a baffle 1 8 therein (see Figure 2) The baffle 18 extends horizontally rearwards from the lower edge of the horizontal aperture 17 and is then curved upwards for a short distance, terminating a distance behind the front wall about equal to half the width of the top wall. Thus, cool air from the room enters the ducts 14, is heated therein and passed up the ducts by convection, enters the heat-exchange chamber 10 in which the baffle '18 causes it to flow over the heated rear wall, thus further heating the air, and finally emerges through the horizontal aperture 17 into the room It will thus be seen that most of the heating of the air is done with heat derived from the combustion 'gases, which heat would otherwise be lost in the flue The combustion gases should pass through the throat at a temperature sufficiently high to ensure that, when the are cooled by the heat-exchange unit, they are still hot enough to give satisfactory conditions in the flue,

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* Worldwide Database * 5.8.23.4; 93p

* GB785700 (A)

Description: GB785700 (A) ? 1957-11-06

Improvements in or relating to domestic open fires


PATENT SPECIFICATION Date of filing Complete Specification: Oct 26, 1954. Application Date: Oct26, 1953 No 29596/53. Complete Specification Published: Nov 6, 1957. 785,700 Index at acceptance:-Class 126, B 2 C( 2 B: 2 C: 3 E), B 17 ? 113 (A: E; H:; J 5 D), B( 21: 29), B 49 (A: Bl A: B 2 C 3 B; C 4), BX, International Classification:-F 24 b. COMPLETE SPECIFICATION Improvements in or relating to Domestic Open Fires We, B FINCH & COMPANY LIMITED, a British Company, of Belvedere Works, Sherwood Road, Barkingside, Essex, STANLEY ERNEST THROWER, a British Subject, of 327 Stradbroke Grove, Ilford', Essex, and JACK BUTLER, a British Subject of 5, Milkwell Gardens, Woodford Green, Essex, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention is concerned, with domestic open fires of the kind having a fire back which, as it extends upwards, is inclined forwardly towards the top of the fire opening, (by which is meant the upright opening, usually rectangular, at the front of the fire) a throat being provided adjacent the top of the fire opening for communication with a flue One important cause of inefficiency in domestic open fires has been the considerable loss of heat owing to the large volume of air, not passing through the bed of combustible material, which is heated and passes up the flue A result of this high rate of passage of air is that a great deal of cooler air iw drawn into the room, thus lowering the room temperature The present invention has, for an object to provide a domestic open fire which has a lower rate of passage of

this, diluent or secondary air than domestic open fires of the substantially same size commonly used heretofore. According to the invention, a domestic open fire is characterised, in that a damper is provided at the throat, which damper is adjustable to vary the area of the throat and which is so shaped and so arranged that its forward surface provides a smoothly curved, upwardlyextending continuation of the front surface of the fireback rear wall, at least in the position; in which it gives a minimum area of throat. In the preferred form of the invention the height of the fire opening is such that the area of the fire opening available for the passage of diluent air is at or near the lowest value possible whilst being sufficient for the desired radiation of heat from the fire and at the same time such that the proportions of the fire opening do not appear to the eye to depart substantially from those which are conventional Diluent air is drawn into the fire opening above the fret or the top of the bed of coal or other burning material, so that the height of the fire opening which is selected will depend to some extent on the height of the bed of coal or the fret It will be appreciated that the area of the fire opening which is selected will normally be a compromise between the values most suitable for various purposes The public has become used to fire openings of more or less standard proportions, and in carrying out this invention commercially it is undesirable for the height of the fire opening in relation to the width to be too much less than that conventionally used, although it is essential for it to be less to some extent. It has been found that the area of the nominal 16 inch wide fire opening available for the passage of diluent air is preferably of the order of 144 square inches In a fire opening of the standard width of 16 inches, this means that only the top 9 inches or so should be available for the intake of diluent air; the total height of the fire opening may be considerably more than 9 inches' since the lower part is taken up 'by the fret and the bed of fuel', if that bed rises above the fret as is usual Thus a suitable height for a fire opening of 1,6 inches width may be about 1,6 inches The width may be increased but the height preferably remains the same (i e. about 16 inches) Preferably the top of the fire opening com. prises the bottom of a wall providing the -front wall of the throat and is rounded from front to backs so that diluent air entering the throat passes only over a smoothly curved surface, Thus none of the gases entering the throat encounter any sharp edges or corners which would cause undesirable eddies and loss of gas velocity Also the throat is disposed close to the front of the fire. The top portion of the damper preferably provides the rear wall of the throat, and, is slightly higher than the top of the fire opening.

The damper, in a preferred arrangement, is pivotally arranged to move between a rear position in which the throat has a maximum area and a forward position in which the throat has a minimum area and stop means are provided for locating the damper in those positions. The forward stop means may be adjustable so that the minimum area can be adjusted to suit any particular flue conditions. Normally the minimum area will be of the order of 10 square inches, but in some cases an area of 5 square inches is possible The minimum area should be as small as possible while giving adequate draught conditions and avoiding smoking at the fire opening. It is advantageous if the damper is such that, when it is in its forward position, its front surface first provides a continuation with the same degree of curvature as the front surface of the fireback rear wall, and, towards the top of the damper, curves upwardly to provide the rear surface of the throat. A combined smoke chamber and soot trap may be provided immediately above the throat and extending rearwardly therefrom. Preferably the smoke chamber has a smoothly curved rear wall extending first downwardly away from the throat opening then upwardly, the rear surface of the damper providing at least part of ithe downwardly extending portion of the rear wall. The front wall of the smoke chamber preferably extends first upwardly then rearwardly in a smooth curve from the throat and preferably the top of the damper is rounded frcm front to back Thus all the front and rear surfaces encountered by the combustion products and the diluent air are smoothly curved. The side edges of the fire opening are also preferably smoothly curved rearwardly. In order to reduce heat losses from the fire, the fireback may have a rear packing of insulating material, and the back hearth may have a similar packing In this case the fireback and the back hearth should be of refractory material to withstand the high temperatures which result. The fire can be made still more effective by providing said front wall of ithe smoke chamber as a hollow chamber, preferably of metal having an inlet or inlets for cool air and, an outlet for heated air The inlets of cool air may receive the air from upright ducts at the sides of the fireback so as to be heated thereby, which ducts receive air and heat it before it passes into the hollow chamber for further heating Such arrangements are dealt with in our copending Application No. 29554/53 (Serial No 785,699). The gases passing through the throat will be of a sufficiently high temperature and moving at a sufficiently high velocity, as a

consequence of the features set out hereinbefore, that loss of heat to the hollow chamber will not normally prevent ample pressure being maintained in' the flue. It is an important advantage of the fire according to this invention, that it can be constructed as a unit having the smoke chamber pre-formed therein and that a builder can simply leave a cavity when building the flue, into which cavity the fire is thereafter fitted. The following is a description by way of example of a domestic open fire in accordance with the invention reference being made to the accompanying drawings, in which Figure 1 is a cross-sectional elevation of the fire, Figure 2 is a perspective view of the fire, partly in cross-section, Figure 3 is a plan view of a bearer bar for carrying the damper, 90 Figure 4 is a cross-sectional view of the bearer bar, Figure 5 is an elevation of the damper, Figure 6 is an end view of the damper, Figure 7 is a cross-sectional view of the 95 damper, Figure 8 is a horizontal cross-sectional view through the lower part of the fire, Figure 9 is an upright cross-sectional view through a modified fire with a back boiler 100 and showing a shielding hood, and Figure 10 is a perspective view of the back boiler and its base block. The fireback 10 is of refractory concrete or fireclay and is curved forwardly as it ex 105 tends upwards It stands on a hearth slab 11 also of refractory concrete or fireclay Behind and at the sides of the fireback 10 and beneath the hearth slab 11 are packings 12 of insulating light-weight concrete which is resistant to 110 high temperatures A damper 13 is pivotally mounted on a straight cast iron or steel bearer bar 14 on the top of the fireback 10 The bearer bar 14 has a flat base 15 resting along the Itop of the fireback 10 with an upwardly 115 extending front flange 17 which forms a substanitially uninterrupted upward continuation of the front surface of the fireback 10 Side extensions, 18 of the bearer bar are embedded in the sides of the fire The bearer 'bar 14 120 has upstanding end walls 19 with substantially semi-circular recesses in the middle of the top edges thereof The damper 13 comprises a metal frame of generally rectangular form (having for example external dimensions of 125 about 4, and 14 inches) The top and bottom members of the frame comprise parallel strips 20, 21 each arcuate about a horizontal axis and having its concave side facing inwardly with respect to the damper The bottom mem 130 785 s,700 785,700 ber 21 of the frame has a greater radius of curvature than the upper member The top and bottom members 20, 21 are connected by two parallel side members 16, 22, each of which has its profile smoothly curved and conforming at the ends to the arcuate contours of the top and, bottom members The front edge of each of the side members 16, 22 is slightly convex while the back edge is concave.

The top and bottom and side members are of cast iron or steel and they carry a filling 23 of refractory concrete or fireclay which completely fills the frame and conforms to the profile of the side members 16, 22 At the bottom of each of the side members and on the axis of curvature of the bottom edge is a pivot spin or lug 24 of part-circular shape resting in the semi-circular recess of the corresponding end, wall 19 of the bearer bar 14 The damper 13 is thus pivotally mounted and can be swung backwards and forwards 'by means described hereinafter Also, the mounting is such that the damper can be easily removed by a suitable tool for access to the flue by Z 5 a sweep's brush, The outside of each of the side members 16, 22 of the frame has two flat abutment surfaces 25, 26 extending in opposite and generally radial directions from the pivot or lug 24 The arrangement of the two abutment surfaces 25, 26 of each side member 16, 22 is such that one of them at a time can engage the top edge of the corresponding end, wall 19 of the bearer member 14, thus limiting the forwards 'or tbackwards movements of the damper 13 in a desired position The whole damper assembly is so consfructed and arranged that, whatever the position of the damper in or between, the two igmiting positions, the front and back surfaces thereof provide substantially uninterrupted smoothly curved upward continuations of the front and back surfaces, of the fireback rear wall. A hollow metal chamber 27 extends hornzontally across the top of the fire opening. The hollow chamber has a flat top and front walls 28, 29 of about the same width At the bottom of the front wall the wall of the ichamber is curved rearwardly and then upwardly Ito provide a portion 30 of substantially semi-circular contour with a diameter about half the width of the op wall 28 From the semi-circular portion 30 the wall of the chamber is smoothly curved upwards to, join the rear edge of the top wall,, the curvature being firstly, and for the greater part of the distance, concave and then convex Said semi-circular bottom portion 30 of the hollow chamber 27 is at the same level as the top of the damper 13 ' in its forwardmost position When the damper is in its rearmost position, its top is only slightly higher than the semi-circular bottom portion. Passing from front to back through the hollow chamber 27 at one side thereof is a tube 31 in' which a push/pull rod 32 reciprocably fits The push/pull' rod 32 extends out at the front of the fire where it has a manipulating knob and extends rearwardly behind the hollow chamber 27 This rear extension carries two parallel bars 33 arranged one beyond the other and extending downwardly and slightly rearwardly Fitting into the space between the parallel bars is a stud 34 extending sideways from the top portion of the side member 16, of the

damper frame Thus, by reciprocating the push/pull rod 32, the damper 13, can be swung between its two limiting positions, the stud 34 sliding in the space between the parallel bars 33 When, the fire is first lighted particularly with bituminous fuels, a considerable amount of smoke is evolved and the damper 13 is swung to its rearmost (i e most open) position When the fire is burning well and the amount of smoke is less, the damper is swung to its forwardmost position to reduce the area of the throat (which is defined at back and front by the top of the damper 13 and said semicircular portion 30 of the hollow chamber). In this forwardmost position, the front surface of the damper 13, provides a continuation of the front surface 35 of the fireback rear walls, which continuation has substantially the same degree of forward: curvature as the front surface 35 of the fireback 10 '; in the rearmost position, the front surface of the damper still provides a continuation of the front surface of the damper, but with a curvature which is more in an upwards direction The distance between the lowermost part of 'said semicircular portion 30 and the hearth (i e the effective height of the fire opening) is 16 inches and the width of the fire opening is the same A fire basket and fret are provided of such dimensions, that the area available for the passage of diluent air is 'of the order of 144 square inches, 'For an 18 inch wide fire opening the preferred area available for the passage of diluent air is 162, square inches, for a 20 inch width it is 180, square inches and for a 24 inch width it is 216 square inches. The insulating packing 12 behind the fireback 10 has a recess 36 at its top which provides a smoke chamber extending rearwardly from the damper 13 The wall of the smoke chamber comprises the rear surface of the damper 13 which provides a concave downwardly-extending curve This curve merges with the curve of the surface 'of the recess 3 '6 in the packing 12 which is concave and upwardly-extending 'and terminates in a straight upwardly-extending portion 37 inclined slightly rearwardly The rear wall; of the smoke chamber is thus provided by the insulating packing 12 and the front wall by the aforesaid hollow chamber 27 The side walls, of the smoke ehamber have inner surfaces 38 inclined towards leach other in the usual way The tops of the rear wall and side walls and' of the 785,700 hollow chamber are flat and lie in a single plane. On each side of the fire opening immediately next to the sides of the fireback are formed two vertical ducts 39 with open outer sides Each duct opens at its top into the aforesaid hollow chamber 27 at the lower end of the side thereof and below the level of a horizontal baffle 40 therein The hollow chamber 27 has a narrow horizontal aperture 41 extending along its front adjacent the top thereof The

horizontal baffle 40 extends rearwardly from the lower edge of the narrow aperture 41 and is inclined' upwardly towards its rear edge, which is spaced away from the rear wall of the hollow chamber 27 Cold air is thus drawn in through the open outer sides of the vertical ducts 39 and heated therein by heat coming from the sides of the fireback 10. The main supply of cold air for convection may be introduced to the lower ends of ducts 3,9 by connecting pipes or channels (not shown) from any convenient points at low level from the chimney breastwork or from an external source in, accordance with conventional practice C Oving to said baffle 40 the air is then caused to sweep against the back wall of the hollow chamber 27 which is heated by hot gases in their passage through the smoke chamber, and the further heated air finally passes into the room through the horizontal aperture 41 The hollow chamber 27, being immediately above the fire is also heated by radiant heat therefrom As mentioned hereinbefore, the damper 13 has integral therewith abutment surfaces 25 for limiting the forward movement of the damper into the restricted position with minimum area. The minimum area is somewhat critical, since it should be as small as possible while not being so small as to cause smoking at the fire opening Since the area necessary to avoid smoking depends on a number of factors, such as the construction of the flue, it is desirable for the minimum area of the throat to be adjustable For this reason, and adjusting screw 42 is provided extending rearwardly through the hollow chamber 27 and -having its inner end so disposed as to be capable of being engaged by the forward-most one of the two parallel bars 33 on the pushpull rod 32 Thus the forward movement of the damper 13 is limited by engagement of the bar 33 with the adjusting screwv 42 When the fire is installed the screw 42 is adjusted to give the required restricted throat area. Thereafter, the damper is simply moved into its rearmost position when lighting the fire and into its forwardmost position when the fire is burning well For smokeless fuels a suitable minimum throat area was found in one case to be 5 square inches as compared, with 40-90 square inches with ordinary open fires. Surrounding the fire opening is a meta'l frame or arch 43 having two vertical side members and a horizontal cross member connecting them at the top The frame 43 lies in front of and abuts or is closely sealed to said hollow chamber 27 and' the leading edges 74 of the fireback 10 The inner edges of the side members of the frame 43 define the sides of the fire opening, but the lower edge of the cross-member is higher than said semi-circular bottom portion 30 of the hollow chamber 7. 27 and thus constitutes a "false" top to the fire opening The reason for this is that to the eye the fire opening will be defined by the

front frame and thus the fire opening appears to be more or less conventional dimensions 84 while in fact the effective height of the opening is less than usual The side and cross members of the frame 43 have wide curved flanges on their inner sides, the wider flanges being generally convex as they extend rearwardly 8 A decorative surround 44 is provided on the wall of the room around the frame 43, the surround being laterally isolated from the side members of the frame by narrow air gaps which also admit air to the vertical ducts 39 91 The surround 44 is isolated from the cross member of the frame 43 by a wider air gap at about the same level as the horizontal aper ture 41 in the hollow chamber 27 The bottom surface 45 of the surround above said wider 9 ' air gap is inclined upwardly and rearwardly so as to provide an overlapping front " lip " ending above the level of said horizontal aperture The cross member has an upper flange 46 extending upwardly and rearwardly with 10 a forwardly-concave curvature, which flange 4 ( 1 terminates behind the plane of the aforesaid lip and about - inch below the level thereof, and is spaced in front of and terminates level or above the top edge of the hori 10 zontal aperture 41, which is thus masked from view. The whole structure described, except the back hearth (<i e the hearth slab 11 and its packing 12) and the surround 44, is formed 11 as an integral unit, so that a builder can construct a cavity at the bottom of the flue into which the unit is inserted Since the form of the smoke chamber is not then left to the individual builder's discretion, as has been usual 11 by suitably choosing the form of the smoke chamber of the unit all risk of faulty construction by the builder is avoided The insulating packing 12 behind the fireback 10 is surrounded by expanded metal lathing 47, 12 or similar reinforcement. The builder will' usually instal a weight bearing precast lintel block 48 of suitable dimensions in the usual way at the top of the cavity and then build the flue immediately 12 off the lintel block whereafter the unit is inserted Asbestos rope seals 49 are provided between the top of the unit and the lintel block 48, and the passage through the lintel block provides a smooth continuation of the 1. - 78,0 5 smoke chamber leading to the flue The unit can readily be removed after first removing the damper 13 and then the seals 49, e g for repair, and then replaced. When the fire is being used with the damper 13 in its forward position, products of combustion flow smoothly up the front surfaces 'of the fireback 10 and the damper 13 into the throat Diluent air also flows, past the smoothly curved surfaces of the front frame 43 and of the semi-circular portion 30 of the hollow chamber 27 into the throat The mixture of combustion products and diluent air then sweeps smoothly upwards over the rear surface of the hollow chamber 27,

through the lintel block 48 and into the flue Down draught gases from the flue flow smoothly down over the curved rear wall of the smoke chamber 36 and up over the rear surface of the damper 13 to meet the hot gases which have just passed through the throat The cooler and hot gases mix and pass up the flue It will be seen that in the whole of their passage through the fire the gases encounter only smoothly curved surfaces, thus avoiding the formation of currents and eddies leading to the emission of smoke into' the room. The use of the insulating packing 12 with the fireback 10, and the low intake of diluent air results in such reduced heat losses that the fireback may become incandescent The fuel bed is not subjected to undesirable cooling by heat loss through the fireback, and more efficient combustion of fuel is possible Also the temperature of the gases passing through the throat is higher than was usual heretofore, so that even though they lose heat to the hollow chamber 27 they enter the flue at a temperature higher than heretofore usual This together with the high velocity imparted to the flue gases by the throat arrangement, avoids or greatly reduces the likelihood of trouble owing to down-draught in the flue. In carrying out a test in an average room with the fire described in detail above, it was found that the volume flow of combined air and flue gas was only about 2,500 cubic feet per hour, as compared; with 6-15,000 cubic feet per hour with ordinary open fires. The arrangement is such that it is not necessary to provide off breaks in the chimney construction in order to prevent direct access, e.g of rain, into the fire. Also, the smoke chamber provides a trap for falling soot. In a modified construction, the rear wall of the fireback 10 is replaced by a back boiler as shown in Figures 9 and 10 The front face of the back boiler is of substantially the same curvature as the front face of the rear wall of the fireback 10 in the construction described hereinbefore No rear flueway is provided for the boiler thus avoiding the necessity for frequent cleaning which exists with such rear flueways The boiler 50 rests on a refractory base block 51 By removing ithe horizontal water pipes (not shown) which pass through the breast-work and fit in holes 52, 53 in the boiler, the whole unit may be removed The refractory base block 51 can then 70 be removed to give access to a cleaning hole 54 in the bottom of the boiler. In each of the above-described constructions a fret 55 is provided across the bottom of the frame 43 and cast integrally therewith The 75 fret 55 is provided in known manner with an aperture 56 for the inlet of combustion air and with a cover plate 57 which is adjustable to control the flow of combustion air through the aperture 56 A removable frame 5,8 fits 80 within the fireplace, being supported at the rear by

two integral legs 59 and at the front by an overhanging lip 60 which fits over the top of the fret 55, an asbestos seal (not shown) being provided therebetween to prevent the 85 passage of air A fuel grid 61 having parallel bars extending from the back to the front of the fire cvests removably on ledges along the sides of the frame 58 A removable sheet iron ash pan '62, is provided beneath the grid 61 90 and a removable fuel deepening bar 63, to permit of a deeper fuel bed, is supported by lugs 64 which fit into holes in the overhanging lip 60. In the construction first-described above, 95 cast iron linings 65 may be provided for the fuel bed, resting on the frame 58 'When a back boiler is provided the rear cast iron lining is omitted. Where a back boiler is provided, it may 100 sometimes (usually in summer) be desirable to obtain hot water without heating the room. For this reason there is provided a hood 66 (see Figure 9) which may be fitted to the front of the fire when required The hoodl 66 105 is preferably of aluminium and has its inner surface polished so that radiant heat from the fire is reflected back into the fireplace so that the heat is used for heating the water and not the room The hood is supported by a lip 110 along its upper edge which is engageable over the aforesaid upper flange 46 of the frame 43 and under the top wall of the hollow chamber 27 thus closing the outlet from the hollow chamber and preventing the passage of 115 heated air into the room It is important that sufficient air can enter under the hood to prevent the device from acting as a draw plate and, also that the hood should fit snugly against the fire 120 place surround at the top and sides The shape of the hood may be varied to suit the particular itype of firegrate employed.


* GB785701 (A)

Description: GB785701 (A) ? 1957-11-06

Improvements in or relating to new compositions of matter suitable fortransmitting power in and lubricating the parts of a hydraulic system

Description of GB785701 (A) Translate this text into Tooltip



AMENDED SPECIFICATION Reprinted as amended in accordance with the Decision of the Superintending Examiner acting for the Comptroller-General dated the twentyfirst day of April 1958, under Section 29, of the Patents Act, 1949. PATENT SPECIFICATION Inventor: DOUGLAS H MORETON M 4 a g e Date of Application and filing Complete Specification: Jan 26, 1954. No 2332154. Complete Specification Published: Nov 6, 1957. Index at acceptance:-Class 69 ( 2), P 12. International Classification:-FO 3 c. COMPLETE SPECIFICATION Improvements in or relating to New Compositions of Matter Suitable for Transmitting Power in and Lubricating the Parts' of a Hydraulic System We, DOUGLAS AIRCRAFT COMPANY, INC, a corporation organised under the laws of the State of Delaware, United States of America, of 3000 Ocean Park Boulevard, City of Santa Monica, State of California, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates to a fluid composition useful particularly for transmitting power in hydraulic power systems and especially as a non-flammable hydraulic fluid in the hydraulic systems and especially as a non-flammable hydraulic fluid in the hydraulic systems of aircraft and to a method of transmitting power in and of lubricating the parts of a hydraulic system. The present invention provides a composition comprising ( 1) a dialkyl aryl phosphate in which the alkyl radicals have from 4 to 8 carbon

atoms and the aryl radical has 6 or 7 carbon atoms; and ( 2) a mihor but sufficient proportion of-a poly-alkyl methacrylate soluble in said phosphate and having a molecular weight within the range of 1,500 to 14,000 and in which the alkyl group has from 2 to 8 carbon atoms to increase the viscosity of the composition at elevated temperatures and to increase the viscosity index of the composition. A number of fluids are known which are intended for use to transmit power in hydraulic systems including some known fluids intended 3 $ for use in the hydraulic systems of airplanes. Howev&r,-the hydraulic power systems of airlPrice 3 s 6 d l craft for operating various mechanisms of an airplane impose stringent requirements on the hydraulic fluid used Not only must the hydraulic fluid for aircraft meet stringent functional and use requirements but in addition such fluid should be as highly non-flammable as possible and must be sufficiently nonflammable to satisfy aircraft requirements for fire resistance The viscosity characteristics of the fluid must be such that it may be used over a wide temperature range; that is adequately high viscosity at high temperatue, low viscosity at low temperature and a low rate of change of viscosity with temperature Its pour point should he low Its volatility should be low at elevated temperatures of use and the volatility should be balanced; that is, selective evaporation or volatilization of any important component should not take place at the high temperatures of use It must possess sufficient lubricity and mechanical stability to enable it to be used in the self-lubricated pumps, valves, et cetera employed in the hydraulic systems of aircraft which are exceedingly severe on the fluid used It should be chemically stable to resist such chemical reactions as oxidation, decomposition, et cetera so that it will remain stable under conditions of use against loss of desired characteristics due to high and sudden changes of pressure, temperature, high shearing stresses, and contact with various metals which may be, for example, aluminum, bronze, steel, et cetera It should also not deteriorate the gaskets or packings of the hydraulic system It m'ust not adversely affect the materials of which the systemis-constructed, and in the 55701 event of a leak should not adversely affect die various parts of the airplane with which it M-ay accidentally come in contact It should not be toxic or harmful to personnel who may come in contact with it Furlhermore, in addition to all such requisites for aircraft use, the fluid must be sufficienlty non-flammable to meet aircraft requirements. Numerous hydraulic fluid mixtures have been suggested Light petroleum oil fractions to which suitable pour point depressants, viscosity index improvers, inhibitors, et cetera have been added are among the best so far proposed and these have been used somewhat extensively as

aircraft hydraulic fluids These materials, however, are two readily flammable, have a low autogenous ignition temnperature, burn readily once ignited and have a high heat value These characteristics are particularly undesirable in aircraft where necessity dictates the use of hydraulic lines in close proximity to electrical systems and to engines where a leakage of hydraulic fluid at high pressure through a crash of the airplane or failure of the hydraulic system Yihile in flight may result in fire None of these prior materials will meet the requirements of an aircraft hydraulic fluid and at the same time be sufficiently nonflammable to meet this exceedingly important requirement for aircraft use. In many hydraulic systems power must be transmitted and the frictional parts of the systems lubricated by the hydraulic fluid used. The parts which are so lubricated include the frictional surfaces of the source of power, which is usually a pump, valves, operating pistons and cylinders,,ond fluid motors The hydraulic system may be of either the constant-volume or the variable-volume type of system. The pumps may be of various types, including the piston-type pump, more particularly the variable-stroke piston pump, the variabledischarge or variable-displacement piston pump, radialpiston pump, axial-piston pump, in which a pivoted cylinder block is adjusted at various angles with the piston assembly, for example, the Vickers Axial-Piston Pump, or in. xsh-cl the mechanism which drives the pistons is set at an angle adjustable with the cylinder block; gear-type pump, which may be spur, helical or herringbone gears, variations of internal gears, or a screw pump, or vane pumps. The valves may be stop valves, reversing valves, pilot valves, throttling valves, sequence valves or relief valves Fluid motor are usually constant or variable-discharge piston pumos caused to rotate by the pressure of the hydraulic fluid of the system with the power supplied by the pump power source Such a hydraulic motor may be used in connection with a variable-discharge pump to form a variable-speed transmission. Accordingly, a large number of requirements are placed on the method of performing thes 2 functions of transmitting power in and lubricating the frictional parts of such hydraulic systems, depending upon the particular hydraulic system and its particular use Among the stringent requirements of the method of transmitting power in and lubricating the parts 70 of such a system are that it must be done by means of a fluid having satisfactory properties such as low vimcosity at low temperatures of use, high viscosity at high temperatures of use, low rate of change of viscosity with tempcra 75 ture over the temperature range of use, particularly high viscosity index,

lubricating properties, density, chemical stability, resistance to oxidation, resistance to; emulsification, resistance to the formation of gum or sludge 80 Good lubricating properties are especially important These particularly include lubricity and film strength Good lubricity and filin strength lessen wear of moving parts in pumps and valves where the clearance between frie 85 tional surfaces may be so small that only microscopically thin films of lubricants are possible Pressures between some of the moving parts may be very high To avoid excesstve wear or seizure, especially in the case of 90 high fluid pressure, the hydraulic fluid should provide a strong lubricating film which will resist the pressure and wiping action between. the moving parts at the temperatures of operation icear of the parts of a hydraulic system 95 allows internal leakage and excessive fractional heat Load-carrying capacity or lubricity is also important in some hydraulic systems. Wear at the glands and sealing elements of the hydraulic system is undesirable because it 100 leads to external leakage of the fluid Accordingly, it is desirable that the hydraulic fluid also lubricate the areas of contact with the sealing means. The requirements for the hydraulic system 105 of an airplane are particularly severe These include a good lubricity to effectively lubricate. the moving parts of the system, satisfactory viscosity at low as well as high temperatures at which the aircraft may have to operate, low 110 rate of change of viscosity with temperature, particularly high viscosity index, stability under conditions of use against loss of the desired characteristics due to high and sudden changes of pressure, tempertaure, high shearing stresses, 115 non-corrosiveness to metal parts which may Lbe bronze, aluminum, steel et cetera, and 'he property of not deteriorating gaskets or packings, and in addition to all such requirements for aircraft use, the fluid must also be h Wghly 120 non-flammable or fire-resistant The parts of the hydraulic system of aircraft are required to be as light in weight as possible and this factor results in imposing additional severe lubrication requirements and usually higher 125 fluid temperatures. Among the particular frictional surfaces which must be lubricated are hard steel on hard steel, particularly ball bearings ard gear teeth, hard steel on cast iron, particularly slid 130 785,701 785,701 ing friction between such surfaces, hard steel on bronze or alloy bronze, and metal in contact with elastomner seals, particularly steel or bronze on neoprene, Buna N, butyl rubber, silastic rubber, and natural rubber The word "Buna" is a registered Trade Mark The hard steel may be chrome plated Such frictional surfaces particularly include, in a Vickers Axiai Piston Pump used in the hydraulic systems of aircraft,

steel ball bearings on steel ball retainer, steel universal link on steel universal link socket, steel pistons on the bronze cylinder walls, bronze cylinder rotating on steel valve plate, and steel shaft on butyl rubber shaft seal. In accordance with this invention, the discovery has been made that hydraulic fluids surprisingly satisfactory for aircraft hydraulic systems can be made by compounding a relatively small proportion of a suitable resinous or polymerized alkyl methacrylate (poly alkyl methacrylate) with a major proportion of suitable di-alkyl aryl phosphate. It is an especially significant feature of the compositions of this invention that in addition to having a large number of properties making them suitable for the purposes as indicated above, these compositions of our invention have a very surprising combination of high fireresistance or non-flammability and low viscosity at extremely low temperatures, such as -65 F, together with an adequately high viscosity at such operating temperatures as 'F and 210 "F Moreover, the resulting viscosity index is unexpectedly high All these striking factors must be taken in consideration with the fact that the compositions are homogeneous; that is, the components in accordance with our invention are surprisingly and unexpectedly compatible It is also a striking feature in accordance with the invention that not only are these features, obtained, but, in addition, the resulting composition is highly and surprisingly satisfactory with respect to the other properties and requirements referred to, above. The dialkyl monoaryl phosphates employed in the composition, of this invention are those in which each of the two alkyl radicals has from 4 to 8 carbon atoms and the aryl radicals have from 6 to, 7 carbon atoms, that is, may be phenyl or cresyl (methyl phenyl) radicals. These phosphates particularly include dibutyl phenyl phosphate, di-amyl phenyl phosphate, di-hexyl phenyl phosphate, di-octyl phenyl phosphate, di-( 2-ethyl hexyl) phenyl phosphate, dibutyl cresyl phosphate, butyl-( 2-ethyl hexyl) phenyl phosphate, di-iso-octyl phenyl phosphate, butyl iso-octyl phenyl phosphate. Of these phosphates dibutyl phenyl phosphate is preferred. The poly-alkyl methacrylates especially suitable for the purpose of this invention are in general those resulting from the polymerizat Von of alkyl methacrylates in which the alkyl groups have from 4 to 8 carbon atoms The alkyl groups may be mixtures such as derived from a mixture of alcohols, and in which case there may be included some alkyl groups having as low as 2 carbon atoms and as high as 8 70 carbon atoms, but the mixture should predominate in alkyl groups having from 4 to 8 carbon atoms The number of carbon atoms in the alkyl group should be such that the polymer is compatible with the

particular phos 75 phate used For this purpose in general it is preferable that the number of carbon atoms in the alkyl group of the polyalkyl methacrylate correspond with the number of carbon atoms in the afkyl groups of the dialkyl aryl phos 80 phate, or with the average of the carbon atoms of both such alkyl groups For dibutyl phenyl phosphate, for example, the alkyl group should have from 4 to 6 carbon atoms, and preferably 4 carbon atoms Thus, for dibutyl phenyl 85 phosphate the poly-alkyl methacrylate may be poly-butyl methacrylate, poly-amyl methacry late or poly-hexyl methacrylate but is preferably poly butyl methacrylate T;he alkyl groups may be branched chain, but are preferably 90 normal alkyl groups The molecular size of the polymerized alkyl methacrylate should be great enough to increase the viscosity of the dialkyl aryl phosphate to which added and small enough to be compatible therewith as is 95 generally understood with regard to improvement in viscosity index The average molecular weight should generally be within 2,000 to 12,000 and the molecular weight range should be from about 1,500 to 14,000 The 100 poly-alkyl methacrylate should be such and in sufficient proportion to increase the viscosity at elevated temperatures, for example, at 2100 F. to at least about 3 0 centistokes, and to increase the viscosity index, for example, to 105 above 100, and preferably to above 150. In compounding the compositions of this invention, the alkyl methacrylate polymer may be added to the phosphate or mixture of phosphates, or the monomer may be polymerized in 110 situ' in the phosphate or mixture of phosphates by adding the unpolymerized alkyl methacrylate ester thereto and then polymerizing the monomer to the desired degree. A minor proportion and particularly from 115 0.2 to 10 per cent by weight of the poly-alkyl methacrylate (exclusive of any solvent) is employed in the composition of this invention, and preferably a proportion within the range from 2 to 6 per cent This percentage of poly 120 alkyl methacrylate is based on the sum of the phosphate and polymer as being 100 per cent. The following examples will further illustrate the present invention: EXAMPLE 1: 125 3 per cent by weight of a poly-butyl methacrylate having an average molecular weight of about 9,000 and a range of about 2,000 to 14,000 was dissolved in 97 per cent by weight of dibutyl phenyl phosphate at room tempera 130 ture The resulting composition had the following surprising combination of properties: Viscosity at 210 'F. l OO 1 F. 'F. OF.

Less than Viscosity Index 220 Pour Point Belo No Cloud to 85 F. Autogenous Ignition Temperature This combination of properties is surprising and this fluid is especially satisfactory as a fire-resistant hydraulic fluid for aircraft It is especially unexpected that this particular poly butyl methacrylate was compatible through this wide temperature range and so effective to increase the viscosity index to such a high value as 220 and thicken, that is, for example, increase the viscosity at such elevated temperature as 210 W to the useful value of 4 35 4.35 centistokes 12.50, 586,) 2500 I, w 85 'F. 1100 'F. centistokes. EXAMPLE 2: 4.5 per cent by weight of a poly-hexyl methacrylate having an average molecular weight of about 8,500 and a range of about 2,000 to 14,000 was dissolved in 95 5 per cent by weight of dlibutyl phenyl phosphate at room temperature The resulting composition had the following surprising combination of properties: Viscosity at 210 'F 3 78 centistokes 'F 10 83 Viscosity Index 210 Pour Point -85 'F. No Cloud to 85 F. Autogenous Ignition Temperature 100 'F. This combination of properties is surprising iand this fluid is especially satisfactory as a fireresistant hydraulic fluid for aircraft It is especially unexpected that this particular poly hexyl methacrylate was compatible through this wide temperature range and so effective to increase the viscosity index to such a high value as 210 and thicken, that is, for example, increase the viscosity at such elevated temperature as 210 'F to the useful value of 3 78 centistokes. Thus it will be seen that in accordance with our invention it is possible to make compositions having a surprising combination of properties particularly including a fire resistance as indicated by an autogenous ignition temperature above 1000 'F, a viscosity at 210 'F above 3 0 centistokes and a viscosity at 40 F below 1000, providing a useful composition throughout an exceedingly wide temperature range Moreover, in addition to this specified combination of properties the fluids in accordance with our invention are otherwise satisfactory as fire-resistant hydraulic fluids for aircraft as pointed out above. These compositions of our invention were found surprisingly satisfactory for transmitting power in and lubricating the parts of an airplane hydraulic system having a Vickers AxialPiston Pump as the power source In addition, these compositions also have a high degree of non-flammability or fire-resistance making them eminently suitable

as hydraulic fluids for airplanes These compositions were found especially suitable as lubricants for the frictional surfaces, particularly the combination of such surfaces, of the hydraulic system These particularly include the lubrication of the metalon-metal and metal-on-elastomer surfaces re 75 ferred to hereinabove This lubrication is effected by maintaining a film of the composition between the frictional surfaces It is especiallyx surprising that both functions of transmitting power and lubrication can be so 80 satisfactorily performed by the compositions of this invention while at the same time such compositions are eminently satisfactory in other respects for aircraft use. From the foregoing it will be seen that our 85 preferred invention is illustrated with respect to dibutyl phenyl phosphate as the phosphate in the composition of our invention, but our invention in its broader aspects includes other phosphates as pointed out above and as illus 90 trated in the following examples: The compositions of the present invention are surprisingly satisfactory for transmitting power in and lubricating the parts of DC-4 or DC-6 airplane hydraulic systems having a 95 Vickers Axial-Piston Pump as the power source In addition, these compositions also have a high degree of non-flammability or fireresistance making them eminently suitable as hydraulic fluids for airplanes These composi 100 tions were found especially suitable as lubricants for the frictional surfaces of thz hydraulic system These particularly include the lubrication of the metal-on-metal and metal-on-elastomer surfaces referred to herein 103 above This lubrication is effected by maintaining a fim of the composition between the frictional surfaces It is especially surprising that both functions of transmitting power and lubrication can be so satisfactorily performed 110 785,701 785,701 by the compositions of this invention while at the same time such compositions are eminently satisfactory in other respects for aircraft use. Our copending application No 24223/55 (Serial No 785702) describes and claims a composition comprising ( 1) a dialkyl aryl phosphate in which the alkyl radicals have from 4 to 8 carbon atoms and the aryl radical has 6 or 7 carbon atoms; ( 2) a minor but sufficient proportion of a poly alkyl methacrylate having a molecular weight within the range of 1,500 to 14,000 and in which the allyl group has from 2 to 8 carbon atoms to increase the viscosity of the composition at elevated ternperatures and to increase the viscosity index of the composition: and ( 3) a minor but sufficient proportion of a mixture of an epoxy compound and alkylene bis-aryl sulphide in which the alkylene group has 1 or 2 carbon atoms and the aryl radicals have 6 or 7 carbon atoms to deactivate said composition on copper.

In specification No 740,078 which, although not published at the date of this application, was filed pursuant to an application which is


* GB785702 (A)

Description: GB785702 (A) ? 1957-11-06

Improvements in or relating to new compositions of matter suitable fortransmitting power in and lubricating the parts of a hydraulic system


A high quality text as facsimile in your desired language may be available amongst the following family members:

DE1036437 (B) FR1095699 (A) NL92322 (C) DE1036437 (B) FR1095699 (A) NL92322 (C) less Translate this text into Tooltip



-'i, PATENT SPECIFICATION Date of Application and filing Complete Specification: Jan 26, 1954 Ni 47 <St Ad ha tl Application made in United States of America on Feb 2, 1953.

,, (Divided out of No 785,701) Complete Specification Published: Nov 6, 1957. Index at acceptance:-Cbass 69 ( 2), P 12. hnternational Classification:-FO 3 c. 55,702 l 24223/54. CO.MPLETE SPECIFICATION Improvements in or relating to V New Compositions of Matter Suitable for Transmitting Power in and Lubricating the Parts of a Hydraulic System SPEC Ip ICATIOIU NC e 795,702 In the headlng on page, for t"No 24223154 " read "Nado 24-223/55 " 1. Tn E PATENT OFFICE, 2sth Arovember, 1957 DB 00840/1 ( 15)/3606 150 11/57 R to a method of transmitting power in and of lubricating the parts of a hydraulic system. The present invention provides a composition comprising ( 1) a dialkyl aryl phosphate in which the alkyl radicals have from 4 to 8 carbon atoms and the aryl radical has 6 or 7 carbon atoms; and ( 2) a minor but sufficient proportion of a mixture of an epoxy compound and an alkylene bis-aryl sulfide in which the alkylene group has 1 or 2 carbon atoms and the aryl radicals have 6 or 7 carbon atoms to deactivate said composition on copper. The present invention further provide l. a composition comprising ( 1) a dialkyl aryl phosphate in which the alkyl radicals have from 4 to 8 carbon atoms and the arvl radical has 6 or 7 carbon atoms; ( 2) a minor but sufficient proportion of a polv-alkyl methacrylate having a molecular weight within the range of 1 500 to 14 000 and in which the alkyl group has from 2 to 8 carbon atoms to increase the viscosity of the composition at elevated temperatures and to increase the viscosity index of the composition; and ( 3) a minor but sufficient proportion of a mixture of an epoxy compound and an alkylene bis-arvl sulfide in which the alkylene group has 1 or 2 carbon atoms and the aryl radicals have 6 or 7 carbon atoms to deactivate said lPrice 316 l addition thereto of a mixture of an epoxy compound that is an organic compound containinz an oxvyen atom linked by the two carbon atoms otherwise also linked together either directly or by way of some other link 65 age and an alkylene bis-aryl sulfide in which the alkvlene group has from 1 to 2 carbon atoms and the aryl radicals have 6 or 7 carbon atoms that is, phenyl or tolyl. A number of fluids are known which are 7 X intended for use to transmit power in hydraulic systems including some known fluids intended for use in the hydraulic systems of airplanes However, the hydraulic power systems of aircraft for operating various 75 mechanism of an airplane impose stringent requirements on the hydraulic fluid used. Not onlv must the hydraulic fluid for aircraft meet stringent

functional and use requirements but in addition such fluid So should be as highly non-flammable as possible and must be sufficiently non-flammable to satisfy aircraft requirements for fire resistance The viscosity characteristics of the fluid must be such that it may be used over 8a wide temperature range; that is, adequately high viscosity at high temperature, low viscosity at low temperature and a low rate of change of viscosity with temperature Its pour point should be low Its volatility 90 11 ' 4 _ 11 A , 10 le"l l i,, PATENT SPECIFICATION Date of Application and filing Complete Specification: Jan 26, 1954. 785,702 No 24223/54. ZA Application made in United States of America on Feb2, 1953. | (Divided out of No785,701) Complete Specification Published: Nov 6, 1957. Index at acceptance:-Class 69 ( 2), P 12. International Classification FO 3 c. COMPLETE SPECIFICATION Improvements in or relating to New Compositions of Matter Suitable for Try 'mitting Power in and Lubricating the Parts of a Hydraulic System We, DOUGLAS AIRCRAFT COMPANY, INC, a Corporation organized under the Laws of the State of Delaware, United States of America, of 3000 Ocean Park Boulevard, Santa Monica, California, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a fluid composition useful particularly for transmitting power in hydraulic power systems and especially as a non-flammable hydraulic fluid in the hydraulic systems of aircraft and to a method of transmitting power in and of lubricating the parts of a hydraulic system. The present invention provides a composition comprising ( 1) a dialkyl aryl phosphate in which the alkyl radicals have from 4 to 8 carbon atoms and the aryl radical has 6 or 7 carbon atoms; and ( 2) a minor but sufficient proportion of a mixture of an epoxy compound and an alkylene bis-aryl sulfide in which the alkylene group has 1 or 2 carbon atoms and the aryl radicals have 6 or 7 carbon atoms to deactivate said composition on copper. The present invention further provides a composition comprising ( 1) a dialkyl aryl phosphate in which the alkyl radicals have from 4 to 8 carbon atoms and the aryl radical has 6 or 7 carbon atoms: ( 2) a minor but sufficient proportion of a poly-alkyl methacrylate having a molecular weight within the range of 1,500 to 14,000 and in which the alkyl group has from 2 to 8 carbon atoms to increase the viscosity of the composition at elevated temperatures and to increase the viscosity

index of the composition, and ( 3) a minor but sufficient proportion of a mixture of an epoxy compound and an alkylene bis-aryl sulfide in which the alkylene group has 1 or 2 carbon atoms and the aryl radicals have 6 or 7 carbon atoms to deactivate said lPrice 3/6 l composition on copper. The dialkyl aryl phosphates defined above have a combination of properties which make them especially suitable for use in a hydraulic fluid, especially for aircraft How 50 ever, such phosphates or fluid compositions containing such phosphates are undesirably active with respect to such metals, particularly copper, which may be and usually are present in the hydraulic systems in which 55 such compositions are employed In accordance with this invention, it has been found that such phosphates or fluid compositions containing the same can be deactivated on such metals, particularly on copper, by the 60 addition thereto of a mixture of an epoxy compound, that is, an organic compound containing an oxygen atom linked by the two carbon atoms otherwise also linked together either directly or by way of some other link 65 age, and an alkylene bis-aryl sulfide in which the alkylene group has from 1 to 2 carbon atoms and the aryl radicals have 6 or 7 carbon atoms, that is, phenyl or tolyl. A number of fluids are known which are 70 intended for use to transmit power in hydraulic systems including some known fluids intended for use in the hydraulic systems of airplanes However, the hydraulic power systems of aircraft for operating various 75 mechanism of an airplane impose stringent requirements on the hydraulic fluid used. Not only must the hydraulic fluid for aircraft meet stringent functional and use requirements but in addition such fluid 80 should be as highly non-flammable as possible and must be sufficiently non-flammable to satisfy aircraft requirements for fire resistance The viscosity characteristics of the fluid must be such that it may be used over 85 a wide temperature range: that is, adequately high viscosity at high temperature, low viscosity at low temperature and a low rate of change of viscosity with temperature Its pour point should be low Its volatility 90 Seep 7 1 ?.J O Q A 785,702 should be low at elevated temperatures of use and the volatility should be balanced; that is, selective evaporation or volatilization of any important cornponent should not take place at the high temperatures of use It must possess sufficient lubricity and mechanical stability to enable it to be used in the self-lubricated pumps, valves, et cetera employed in the hydraulic systems of aircraft which are exceedingly severe on the fluid used It should be chemically stable to resist such chemical reactions as oxidation, decomposition, et cetera so that it will remain stable under conditions of use against loss of desired characteristics due to high and sudden changes of pressure,

temperature, high shearing stresses, and contact with various metals which may be, for example, aluminium, bronze, steel et cetera. It should also not deteriorate the gaskets or packings of the hydraulic system It must not adversely affect the materials of which the system is constructed, and in the event of a leak should not adversely affect thj various parts of the airplane with which it may accidentally come in contact It should not be toxic or harmful to personnel who may come in contact with it Furthermore, in addition to all such requisites for aircraft use, the fluid must be sufficiently non-flammable to meet aircraft requirements. Numerous hydraulic fluid mixtures have been suggested Light petroleum oil fractions to which suitable pour point depressants, viscosity index improvers, inhibitors, et cetera have been added are among the best so far proposed and these have been used somewhat extensively as aircraft hydraulic fluids These materials, however, are too readily flammable, have a low autogenous ignition temperature, burn readily once ignited and have a high heat value These characteristics are particularly undesirable in aircraft where necessity dictates the use of hydraulic lines in close proximity to electrical systems and to engines where a leakage of hydraulic fluid at high pressure through a crash of the airplane or failure of the hydraulic system while in flight may result in fire None of these prior materials will meet the requirements of an aircraft hydraulic fluid and at the same time be sufficiently nonflammable to meet this exceedingly important requirement for aircraft use. In many hydraulic systems power must be transmitted and the frictional parts of the systems lubricated by the hydraulic fluid used The parts which are so lubricated include the frictional surfaces of the source Go of power, which is usually a pump, valves, operating pistons and cylinders, and fluid motors The hydraulic system may be of either the constant-volume or the variablevolume type of system. The pumps may be of various types, including the piston-type pump, more particularly the variable-stroke piston pump the variable-discharge or variable-displacement piston pump, radial-piston pump, axialpiston pump, in which a pivoted cylinder 70 block is adjusted at various angles with the piston assembly, for example, the Vickers Axial-Piston Pump, or in which the mechanism which drives the piston is set at an angle adjustable with the cylinder block: gear 75 type pump, which may be spur, helical or herringbone gears, variations of internal gears, or a screw pump, or vane pumps The valves or relief valves Fluid motors are pilot valves, throttling valves, sequence 80 valves of relief valves Fluid motors are usually constant orvariabie-discharge Hri 1 ton pumps caused to rotate by the pressure of the hydraulic fluid of the system with the power supplied by the

pump power source Such a 85 hydraulic motor may be used in connection with a variable-discharge pump to form a variable-speed transmission. Accordingly, a large number of requirements are placed on the method of perform 90 ing these functions of transmitting power in and lubricating the frictional parts of such hydraulic systems, depending upon the particular hydra-ulic system and its particular use Among the stringent requir riots of 95 the method of transmitting power in and lubricating the parts of such a system are that it must be done by means of a fluid having satisfactory properties such as low viscosity at low temperatures of use, high vis loo cosity at high temperatures of use, low rate of change of viscosity with temperature over the temperature range of use, particularly high viscosity index, lubricating properties, density, chemical stability, resistance to oxi 105 dation, resistance to emulsification, resistance to the formation of gum or sludge. Good lubricating properties are especially important These particularly include lubricity and film strength Good lubricity 110 and film strength lessen wear of moving parts in pumps and valves where the clearance between frictional surfaces may be so small that only microscopically thin 'tilms l>; lubricant are possible Pressures between some 115 of the moving parts may be very high To avoid excessive wear or seizure, especially in the case of high fluid pressure, the hydraulic fluid should provide a strong lubricating film which will resist the pressure and wiping 120 action between the moving parts at the temperatures of operation Wear of the parts of a hydraulic system allows internal leakage and excessive frictional heat Load-carrvino' capacitv or lubricitvis also imnort N 5 -'l'125 hydraulic systems Wear at the glands and sealing elements of the hydraulic system is undesirable because it leads to external leakage of the fluid Accordingly, it is desirable that the hydraulic fluil also 'lubricates ia 130 785,702 areas of contact with the sealing means. The requirements for the hydraulic system of an airplane are particularly severe These include a good lubricity to effectively lubricate the moving parts of the system, satisfactory viscosity at low as well as high temperatlires at which the aircraft may have to operate, low rate of change of viscosity with temperature, particularly high viscosity index, stability under conditions of use against loss of the desired characteristics due to high and sudden changes of pressure, temperature, high shearing stresses, non-corrosiveness to metal parts which may be bronze, aluminium, steel et cetera, and the property of not deteriorating gaskets or packings, and in addition to all such requirements for aircraft use, the fluid must also be highly nonflammable or fire-resistant The parts of the

hydraulic system of aircraft are required to be as light in weight as possible and this factor results in imposing additional severe lubrication requirements and usually higher fluid temperatures. Among the particular frictional surfaces which must be lubricated are hard steel on hard steel, particularly ball bearings and gear teeth, hard steel on cast iron, particularly sliding friction between such surfaces, hard steel on bronze or alloy bronze, and metal in contact with elastomer seals, particularly steel or bronze on neoprene, Buna N, butyl rubber, silastic rubber, and natural rubber. The word "Buna" is a Recistered Trale Mark The hard steel may be chrome plated. Such frictional surfaces particularly include, in a Vickers Axial Piston Pump used in the hydraulic systems of aircraft, steel ball bearings on steel ball retainer, steel universal link on steel universal link socket, steel pistons on the bronze cylinder walls, bronze cylinder rotating on steel valve plate, and steel shaft on butyl rubber shaft seal. Those compositions of our invention containing a poly alkyl methacrylate as defined above, have a very surprising combination of high fire-resistance or non-flammability and low viscosity at extremely low temperatures, such as 650 F, together with an adequately high viscosity at such operating temperatures as 100-F and 210 'F Moreover, the resulting viscosity index is unexpectedly high All these striking factors must be taken in consideration with the fact that the compositions are homogeneous, that is, the components in accordance with our invention are surprisingly and unexpectedly compatible It is also a striking feature in accordance with the invention that not only are these features, obtained, but in addition, such compositions are highly and surprisingly satisfactory with respect to the other properties and requirements referred to above. The dialkyl monoaryl phosphates employed in the composition of this invention are those in which each of the two alkyl radicals has from 4 to 8 carbon atoms and the aryl radicals have from 6 to 7 carbon atoms, that is, may be phenyl or cresyl (methyl phenyl) radicals These phosphates 70 particularly include dibutyl phenyl phosphate, di-amyl phenyl phosphate, di-hexyl phenyl phosphate, di-octyl phenyl phosphate, di-( 2-ethyl hexyl) phenyl phosphate, dibutyl cresyl phosphate, butyl-( 2-ethyl hexyl) 75 phenyl phosphate, di-iso octyl phenyl phosphate, butyl iso-octyl phenyl phosphate Of these phosphates dibutyl phenyl phosphate is preferred. The poly-alkyl methacrylates especially 80 suitable for the purpose of this invention are in general those resulting from the polymerization of alkyl methacrylates in which the alkyl groups have from 4 to 8 carbon atoms.

The alkyl groups may be mixtures such as 85 derived from a mixture of alcohols, and in which case there may be included some alkyl groups having as low as 2 carbon atoms and as high as 8 carbon atoms, but the mixture should predominate in alkyl groups having 90 from 4 to 8 carbon atoms The number of carbon atoms in the alkyl group should be such that the polymer is compatible with the particular phosphate used For this purpose in general it is preferable that the num 95 ber of carbon atoms in the alkyl group of the poly-alkyl methacrylate correspond with the number of carbon atoms in the alkyl groups of the dialkyl aryl phosphate, or with the average of the carbon atoms of both such 100 alkyl groups For dibutyl phenyl phosphate, for example, the alkyl group should have from 4 to 6 carbon atoms, and preferably 4 carbon atoms Thus, for dibutyl phenyl phosphate the poly-alkyl methacrylate may 105 be poly-butyl methacrylate, poly-amyl methacrylate or polyhexyl methacrylate, but is preferably poly-butyl methacrylate The alkyl groups may be branched chain, but are preferably normal alkyl groups The 110 molecural size of the polymerized alkyl methalcrylate should be great enough to increase the viscosity of the dialkyl aryl phosphate to which added and small enough to becompatibletherewithas is generally under 115 stood with regard to improvement in viscosity index The average molecular weight should generally be within 2,000 to 12,000 and the molecular weight range should be from about 1,500 to 14,000 The poly-alkyl 120 methacrylate should be such and in sufficient proportion to increase the viscosity at elevated temperatures, for example, at 210 'F. to at least about 3 0 centistokes, and to increase the viscosity index, for example, to 125 above 100, and preferably to above 150 In accordance with this invention it is possible to make compositions having a surprising combination of properties, including a fire resistance as indicated by an autogenous 130 785702 ignition temperature above 10000 F, a viscosity index above 150, a viscosity at 210 'F. above 3 0 centistokes and a viscosity at 'F below 1000 centistokes, providing a useful composition throughout an exceedingly wide temperature range. In compounding those compositions of this invention containing the alkyl methacrylate polymer, the polymer may be added to the phosphate or mixture of phosphates, or the monomer may be polymerized in situ in the phosphate or mixture of phosphates by adding the unpolymerized alkyl methacrylate ester thereto and then polymerizing the monomer to the desired degree. A minor proportion and particularly from 0.2 % to 10 % by weight of the poly-alkyl methacrylate (exclusive of any solvent) is employed in the composition of this invention, and preferably a proportion within

the range from 2 % to 6 %,o This percentage of poly-alkyl methacrylate is based on the sum of the phosphate and polymer as being %. Preferred groups of epoxy compounds suitable for the purposes of the invention include: aryl epoxy compounds such as styrene oxide, alicyclic epoxy compounds such as pinene oxide glycidvl ethers particu-30 arly glycidyl ethers containing one carbocyclic group directly attached to the ether oxygen atom, such as glycidyl phenyl ether. Specific epoxy compounds among the glycidyl ethers which are applicable in compositions of the invention include glycidyl cyclohexyl ether and glycidyl o-cresvl ether Other epoxy compounds among the glvcidvl ethers which may be employed include the alkyl glycidyl ethers, such as glycidyl methyl ether, glycidyl ethyl ether, glycidyl isopropyl ether and their higher molecular weight homologs. Epoxy compounds of the type represented by the olefinic oxides, such as isobutylene oxide and ethylene oxide, propylene oxide, isoprene oxide, decene oxide and butadiene monoxide are also suitable Other suitable epoxy compounds include the aliphatic epoxides, such as epichlorohydrin, glycide, o O chloroprene oxide as well as the alicyclic epoxides such as cyclohexylene oxide and cyclopentene oxide The epoxy compound which is one of the two components of the combination of agents in accordance with this aspect of the invention will usually be present in a proportion from about 02 % to O,/, by weight of the total composition. Where the epoxy compound in the composition, such as a glycidyl aryl ether glycidyl 601 alkyl ether, or an aryl epoxide especially effective results are obtained with from about 1 % to 2 % by weight of such epoxy compound based on the weight of the total composition. The alkylene aryl sulfides may be represented by the formula RSR'SR" where R and R" are aryl radicals having from 6 to 7 carbon atoms, that is, phenyl or cresyl radicals and R' is an alkvlene 70 group having from one to two carbon atoms. Particularly useful members of this group are the methylene bis and the ethylene bis aryl sulfides, such as ethylene bis phenyl sulfide, ethylene bis p-tolyl sulfide the 75 methylene bis phenyl sulfide, and the methylene bis p-tolyl sulfide These alkylene aryl sulfides will be used in a minor but sufficient proportion to obtain the desired deactivation with respect to copper or other metal 80 and usually from about 0 05 %O to 2 by weight of the total composition will be found satisfactory. Our invention will be illustrated by the following examples: 85 EXAMPLE 1. 88 volume per cent dibutyl phenyl phosphate. 12 volume per cent butyl methacrylate polymer solution 90 To this

hydraulic fluid was added 0 5 by weight ethylene-bis-(tolvl sulfl-id and 10 ' by weight of glycidyl phenyl ether. The addition of the mixture of ethylenebis-(tolyl sulfide) and glycidyl phenyl ether 95 deactivated this hydraulic fluid containing the dibutyl phenyl phosphate and butyl methacrylate polymer solution with respect to its corrosion on copper to the surprisingly low value of only a copper metal loss of 100 0.128 milligrams per square centimeter of metal surface The loss on this hydraulic fluid without the addition of the mixture of ethylene-bis-(tolyl sulfide) and phenyl glycidyl etherwas the corresrpondin sly extremel 105 large figure of 17 4 milligrams per square centimeter Moreover, the surprising result was found that this mixture of ethylene-bis(tolyl sulfide) and phenyl glycidyl ether was compatible with this hydraulic fluid, not only 110 at room temperature but also over a wide temperature range, particularly in that no precipitation or clouding appeared. In this example, the butyl methacrylate polymer solution was made un of 30 V by 115 weight of poly-butyl methacrylate in 700. of dibutyl phenyl phosphate, in which the butyl methacrylate was polymerized The poly butyl methacrylate had an average molecular weight of about 8500 and a mole 120 cular weight range of about 2 000 to 14 000. EXAMPLE 2. To dibutyl phenyl phosphate was added 0.5 % by weight of ethvlene-bis-(tol-v-l sullide) and 1 0 ' by weight of phenyl glycidyl ether, 125 which mixture substantially deactivated the dibutyl phenyl phosphate on copper Moreover, as pointed out for Example 1 above, this mixture of ethylene-bis-(tolyl sulfide) and phenyl glycidyl ether was compatible 130 785,702 with the dibutyl phenyl phosphate 1 In the present invention the phenyl gly i cidyl ether in addition to its co-operation i of action with the ethylene-bis-(tolyl sulfide) i to provide copper deactivation, as described i above, also acts as a stabilizer to materially i reduce the rate of decomposition which may, take place in dibutyl phenyl phosphate under I some conditions of use, particularly at such I elevated temperature as 250 'F for example 1 EXAMPLE 3. 88 volume per cent dibutyl phenyl phosphate. 12 volume per cent butyl methacrylate polymer solution. To this hydraulic fluid was added 0 5 % by weight methylene-bis-tolyl-sulfide and 1 0 %i by weight of gycidyl phenyl ether. The addition of the mixture of methylenebis-tolyl-sulfide and glycidyl phenyl ether deactivated this hydraulic fluid containing the dibutyl phenyl phosphate and butyl methacrylate polymer solution with respect to its corrosion on copper to a surprisingly low value f his was in

contrast to the loss on copper for this hydraulic fluid without the addition of the mixture of methylene-bis-tolyl-sulfide and phenyl glycidyl ether which was extremely large Moreover, the surprising result was found that this mixture of methylene-bistolyl-sulfide and phenyl glycidyl ether was compatible with this hydraulic fluid, not only at room temperature, but also over a wide temperature range, particularly in that no precipitation or clouding appeared. In this example, the butyl methacrylate polymer solution was made up of 30 % by weight of poly-butyl methacrylate in 70 % of dibutyl phenyl phosphate, in which the butyl methacrylate was polymerized The poly-butyl methacrylate had an average molecular weiglitof about 8,500 and a molecular weight range of about 2,000 to 14,000. EXAMPLE 4. To dibutyl phenyl phosphate was added 0.5 % by weight of methylene-bis-tolyl-sulfide and 1 0 % by weight of phenyl glycidyloether, which mixture substantially deactivated the dibutyl phenyl phosphate on copper Moreover, as pointed out for Example 3, above, this mixture of methylene-bis-tolyl-sulfide and phenyl glycidyl ether was compatible with the dibutyl phenyl phosphate. The compositions of the present invention are surprisingly satisfactory for transmitting power in and lubricating the parts of DC-4 or DC-6 airplane hydraulic systems having a Vickers Axial-Piston Pump as the power source In addition, these compositions also have a high degree of non-flammability or fire-resistance making them eminently suitable as hydraulic fluids for airplanes These compositions were found especially suitable as lubricants for the frictional surfaces of the hydraulic system These particularly include :he lubrication of the metal-on-metal and netal-on-elastomer surfaces referred to herenabove This lubrication is effected by naintaining a film of the composition be 70 mween the frictional surfaces It is especially surprising that both functions of transmitting Dower and lubrication can be so satisfactorily performed by the compositions of this invention while at the same time such composi 75 tions are eminently satisfactory in other respects for aircraft use. Our copending Application No 2332154 (Serial No 785,701) describes and claims a composition comprising ( 1) a dialkyl aryl 80 phosphate in which the alkyl radicals have from 4 to 8 carbon atoms and the aryl radical has 6 or 7 carbon atoms; and ( 2) a minor but sufficient proportion of a poly-alkyl methacrylate having a molecular weight 85 within the range of 1,500 to 14,000 and in which the alkyl group has from 2 to 8 carbon atoms to increase the viscosity of the composition at elevated temperatures and to increase the viscosity index of the compo 90 sition. We are aware of Specification No 706,566 which claims stable and

non-corrosive, normally liquid compositions comprising 50 % to 95 % by weight of a phosphorus-contain 95 ing organic compound, 0 25 % to 5 % by weight of an organic epoxy compound and 0.025 % to 2 % by weight of an oil-soluble organic sulphide or disulphide.


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