5466 5470.output

* GB785874 (A)

Description: GB785874 (A) ? 1957-11-06

Improvements in and relating to electrical switches

Description of GB785874 (A)

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BE549623 (A) CH333688 (A) DE1154176 (B) FR1133030 (A) BE549623 (A) CH333688 (A) DE1154176 (B) FR1133030 (A) less Translate this text into Tooltip

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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 19, 1956. No 22383/56. Application made in France on July 19, 1955. Complete Specification Published: Nov 6, 1957. Index at acceptance:-Class 38 ( 5), Bl P( 2: 6), B 2 B( 7: 10), B 2 C( 6 F: 9). International Classification:-H Oln H 02 c. COMPLETE SPECIFICATION Improvements in and relating to Electrical Switches We, PAUL JULES T Rous SIER, of 29 bis, Cours Jean Jaures, Grenoble (Isere), France, and HENRI Louis COMEAU, of 41, Rue de Stalingrad, Grenoble (Isere), France, both French Citizens, 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 electrical switches, of the type comprisng three main parts, that is, a stator and a rotor with cooperating contacts, in combination with a protective fuse, and has for its object to provide such devices which overcome many of the disadvantages of those hitherto constructed. Electrical apparatus which include devices according to the invention will be constru Tted in any usual manner, except where it is necessary to introduce modifications to take such devices. In general, an electrical switch, according to the invention comprises a fixed base of insulating material which carries two stationary contacts electrically connected to two spaced-apart terminals for connection to the two leads of the circuit to be controlled, which base has fixed thereto and projecting 0 therefrom two similar spaced-apart and parallel assembly rods the outer ends of which are screw-threaded On these rods is mounted, held assembled and secured in position, a hollow two-part casing which carries two further stationary contacts electrically connected to two spaced-apart sockets which receive and retain the pins of a protective fuse. The hollow two-part casing has mounted to turn therein a two-part rotor of insulating material, each part comprising a similar disc of desired thickness slotted on one face, the two slotted faces being held together with their respective slots in register The other surface of each disc has a central boss which when the parts are assembled is located in a lPrice 3 s 6 d l bearing aperture in one half of the two-part casing and so as to project through such half casing One boss on its exterior projecting portion has a diametrically disposed project 50 ing tongue and the other boss on its projecting portion a diametrically arranged groove which is parallel to the tongue and has a width slightly greater than that of the tongue 55 The slots of the rotor parts when assembled hold within them four more or less radially arranged movable contact arms of conducting material, the inner ends of which have integral pivots which can turn in 60 recesses in the inner faces of the two discs of the rotor, whilst the outer ends of such arms project beyond the periphery of the discs of the rotor so as to co-operate with the four fixed contacts of the stator (coin 65 prised by the base and twopart fixed casing housing the rotor) The four movable contacts are electrically connected together in pairs so that in the "on" position one fixed contact of the base is connected to one fixed 70 contact and its associated socket of the protective fuse through one pair, whilst the other fixed contact and its associated socket of the protective fuse is connected to the other fixed contact of the base, through the 75 other pair. The movable contact arms can oscillate through a desired angle in their slots and have associated springs by which they are kept pressed

into contact with the fixed con 80 tacts when the parts are in the "on" position However, when the device is moved to the "off" position, then abutments remove the spring-pressed movable contacts from the fixed contacts 85 In any known manner, the handle, lever or the like operating the device and consequently the contact-making arms are held in the "on" or "of F" position by spring or otherwise operated catches 90 The operating handle is suitably connected to the rotor, for example by a diametric tongue engaging the diametric groove of one boss of the rotor, or by a diametric groove engaging the diametric tongue of one boss of the rotor This may be the case where only one device according to the invention is being utilised In the more usual case, however, of a multiple switch comprising a plurality of switches according to the invention, for controlling a like number of separate circuits, then each separate switch is connected to the axially adjacent switch by the tongue of one boss of one switch engaging the groove of one boss of the next adjacent switch, and so on. When such a device according to the invention is in the "off" position the arrangement is such that the diametric tongues and slots of the projecting hubs of the rotors are parallel with the parallel assembly rods so that when the securing means, such as nuts, are removed from any one pair of such rods, then what may be termed the "block" of parts, that is, the two-part casing with the enclosed rotor and its parts as well as the protective device, can be withdrawn as a whole by removing it from the pair of assembly rods Further, when thus withdrawn, by separating the two parts of the casing and the -two parts of the rotor, all parts are accessible for inspection, replacement or repair. Correspondingly, a "block" can as readily be re-assembled and replaced in position. In order that the invention may be better understood, it will now be described with reference to the accompanying drawings which are given by way of example only and in which:Fig I is a side elevation of a multiple switch comprisng an assemblage of switches constructed according to one method of carrying the invention into effect. Fig 2 is a plan of Fig 1 with parts removed. Fig 3 is an end view of a switch with parts removed to illustrate the interior structure and with the parts in operative position. Fig 4 is a similar view to Fig 3, but with the parts partly separated. Fig 5 is a somewhatdiagrammaticperspective view of one part of the two-part casing of the switch shown in Figs 1 to 4, but to a smaller scale. Fig 6 is a similar view of the rotor of such switch. Fig 7 is a similar view to Fig 5 but of the other part of the two-part casing.

Fig 8 is a similar view but of the base and assembly rods of the switch shown in Figs. 1 to 4. Fig 9 is a side elevation of a modification. Figs 1 and 2 of the drawings show an assemblage of switches according to the invention constituting a multiple switch Three separate switching devices are shown but it will be realised that fewer or more could be coaxially arranged and controlled from the single handle Further, although no such mechanism is shown in the drawings, it should be realised that the handle has associated therewith any means by which it is 70 held in either the "off" position (that shown in Figs 1 and 2) or the "on" position. Each switch comprises a slotted base 10 of insulating material adapted to support in well-defined fixed positions two contacts 11 75 and 12 of conducting material as well as two terminals 13 and 14 to which the leads of the circuit to be controlled can be connected. Structurally, this is accomplished by two strips 15 and 16 of conducting material, 80 shaped as shown, which are held in position by a base plate proper 17 of insulating material which comes beneath and is secured to the slotted base 10 to hold the strips 15 and 16 firmly in position with their ends pro 85 jecting through the slots of the base 10 as desired The combined base 10 and 17 is apertured at 18 and 19 for securing screws by which it can be mounted in position in an enclosing casing, on a panel, or otherwise 90 Further, the base 10 has secured thereto the lower ends of parallel assembly rods 20 and 21 the upper ends of which are screwthreaded These rods are to receive a twopart hollow casing, one part 22 of which 95 (shown detached in Fig 5) has upper and lower portions 23 and 24 bored for the passage of the rod 20, and similar upper and lower portions 25 and 26 bored for the passage of the rod 21, gaps being left between 100 the parts 23 and 24 and the parts 25 and 26. The upper portion of the part 22 is shaped to receive spaced-apart sockets 27 and 28 of conducting material and these are held in position by integral plates 29 and 30, respec 105 tively, secured to the part of the casing by screws 31 and 32 In addition, the socket 27 and plate 29 have integral therewith a fixed contact 33 of conducting material and similarly the socket 28 and plate 30 have integral 110 therewith a corresponding fixed contact 34. Finally, the part 22 has a central aperture for the purpose hereafter described The other part 36 of the two-part casing is shown in Fig 7 and in an intermediate position at 115 the sides this has portions 37 and 38 bored for the passage of the rods 20 and 21 and adapted to fit in the gaps left between the parts 23 and 24 and 25 and 26, respectively, of the other part 22 of the two-part casing 120 The part

22 also has a central aperture 39 -which is coaxial with the aperture 35 of the part 22 when the parts are assembled. -The rotor is shown in Fig 6 and comprises two similar discs 40 and 41 which when 125 placed together -face to face have a total width slightly less than the axial width of the hollow portion of the two-part casing The disc 40 has a boss 42 adapted to turn in either the aperture 35 or 39, as the case may 130 785,874 pinned thereto an operating handle 61 and in Figs 1 and 2 this operating handle is shown in the "off" position in which all the tongues and grooves of the bosses 42 and 43 are vertical, thereby allowing any one switch 70 block to be detached from the assembly. In place of this arrangement for moving the switches, however, the end member in place of a spindle and sleeve such as 58, 59, can comprise a rotor such as described but 75 without the internal parts, and the exterior boss 43 can have its groove 45 suitably driven by an attached handle or lever Fig. 9 shows such an arrangement and it will be realised how the block thus set up can be 80 utilsed in place of the block shown on the right of Figs 1 and 2. The invention is not limited to the precise forms or details of construction herein described, as these may be varied to suit par 85 ticular requirements.

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* GB785875 (A)

Description: GB785875 (A) ? 1957-11-06

Improvements in or relating to weighing mechanism


COMPLETE SPECIFICATION. Improvements in or relating to Weighing Mechanism. We, MOLINS MACHINE COMPANY LIMITED, a British Company, of 2 Evelyn Street, Deptford, London, S.E.8, 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 concerns improvements in or relating to weighing mechanism, and relates to an improvement in or modification of the mechanism disclosed in British Patent Specification No. 745,350. According to the present invention there is provided in weighing mechanism having a scale pan mounted for movement up and and down with a support element which extends laterally of the scale pan in opposite directions, a pair of stop members having recesses into which opposite end portions of the said support element extend so as to restrict twisting of the said support element and scale pan while permitting upward and downward movement thereof. Apparatus according to the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a sectional side elevation of a weighing apparatus, and Figure 2 is a sectional plan view taken on the line Il-Il, Figure 1. Referring to Figure 1, the weighing apparatus illustrated is generally the same as that disclosed in the specifications and drawings of British Patent Application No. 745,350. Briefly this comprises a weighbeam 1 pivoted at a taut wire 2 attached to the beam and looped about pulleys 3 rotatably mounted on a support 4. One end of the beam 1 is attached to a further taut wire 5 looped about pulleys on a further support 6, which is fixed on members 7 which carry a pair of curved tubular arms 8 which are clamped in the members 7. The lower ends of the arms 8 are fixed to memben. 9 which support a flexible bridge 109 on which is mounted a post 10 to support a scale pan 11. The post 10 passes centrally through a tube 110, which is threaded into a fixed bracket 112. The members 9 also have attached to them a support 12 for a further wire 13 to which is attached one end d a pivoted beam 14. The beam 14 is pivoted at a further wire 15 to which it is clamped, the wire 15 being held by a support 16 fastened to a bracket 17 on the baseplate of the apparatus. A translucent screen 31, arranged at a convenient angle for viewing, is positioned to receive an optical image of a straight horizontal filament in an electric lamp 33. Light from the filament is focused by a lens 34 in an adjustable tube 35, and is projected on to a mirror 36 which is fixed on the weighbeam

1 so as to swing with the latter. The mirror 36 is arranged obliquely so as to reflect the light on to a fixed opposing mirror 37, the light being twice reflected back to the swinging mirror 36. A pair of further fixed mirrors 38 and 39 are arranged side by side at an angle of 90 to each other, the mirror 39 being arranged behind the screen to receive light from the mirror 38, which receives it from the swinging mirror 36. The path of the light is shown by dot and dash lines in Figure 1. The lens 34 is suitably adjusted to cause an enlarged optical image of the filament to be projected on the screen, where it appears as a horizontal bar of light. In the improved construction according to the present invention, means are provided to prevent or restrict accidental twisting of the scale pan 11 and the post 10 and bridge 109 which support it. For this purpose a pair of stop members 113 are fixed to the bracket 112. These members 113, which lie beneath the bridge 109, have recesses 114 in which opposite ends of the bridge can be accommodated so as to limit lateral movement of the ends of the bridge due to accidental twisting of the latter. The recesses are deep enough to allow the bridge to move up and down within them during weighing operations. What we claim is: 1. In weighing mechanism having a scale pan mounted for movement up and down with a support element which extends laterally of the scale pan in opposite directions, a pair of stop members having recesses into which opposite end portions of the said support element extend so as to restrict twisting of the said support element and scale pan while permitting upward and downward movement thereof. 2. Apparatus as claimed in Claim 1, constructed, arranged and adapted to operate substantially as described herein with reference to the accompanying drawings. PROVISIONAL SPECIFICATION. Improvements in or relating to Weighing Mechanism. We, MOLINS MACHINE COMPANY LIMITED, a British Company, of 2 Evelyn Street, Deptford, London, S.E.8, do hereby declare this invention to be described in the following statement: This invention concerns improvements in or relating to weighing mechanism, and relates to an improvement in or modification of the mechanism disclosed in the Specifications and drawings of British Patent Application No. 8846/52 (Serial No. 745,350). In that mechanism, a mirror, arranged to swing with the weighbeam of a weighing device, intercepts light from a fixed source and causes it to

be reflected on to a translucent screen to provide a visual indication of the result of a weighing operation. As described in the Provisional and Complete Specifications of the said Application, with reference to the drawings accompanying the Provisional Specification, an enlarged optical image of a straight horizontal filament 32 of an electric lamp 33 is projected on to a translucent screen 31. Light from the filament is focused by a lens 34 in an adjustable tube 35, and the resulting light beam is thrown on to a mirror 36 which swings with the weighbeam, and is reflected from the mirror 36 on to a fixed opposing mirror 37 from which it is twice reflected back to the swinging mirror 36. Further fixed mirrors intercept the light and reflect it on to the screen 31, where an image of the filament appears in the shape of a straight horizontal bar or light which moves up and down the screen with the movements of the weighbeam. For easy and accurate observation it is desirable that this bar of light should be sharply defined on the screen. To assist in this it is preferable that the filament holder of the lamp should be arranged directly behind the filament in line with the tube 35, as shown in Figure 2 of the drawings referred to above. It is found, however, that in standard lamps of the kind employed, the filament is not always exactly in line with the axis of the lamp, which therefore has to be rotated so as to bring the filament into horizontal position. For this reason it is not always practicable to arrange the filament holder exactly behind the filament, and in such cases it is found that light tends to be reflected on to the screen from the filament holder. Also light is sometimes reflected from the inner surface of the glass envelope of the lamp. Such reflected light sometimes tends to appear on the screen in the form of faint horizontal bands or on occasion as irregularly shaped illuminated areas above or below the image of the filament. This not only tends to confuse and distract the attention of the operator but blurs the definition of the bar of light by whose position on the screen the results of the weighing operation are indicated. According to the present invention there is provided in a weighing device in which an optical image of a lamp filament is projected on to a sheen bv a rcfieo:ing m-mber movable with or in proportion to the angular movement of a weigllbeanl or the like, a mask between said filament and said reflect in. meinb . said nias!, ha.iilg an aperture so propoitonec., in rel^.ion j its distan froze the filament, as to r,ermi 1ii3.ht to pass therethrough directly from said filament, anrj to exclude light reflected from for example, the filament holder or the glass envelope of the lamp.

* GB785876 (A)

Description: GB785876 (A) ? 1957-11-06

Improvements in or relating to neutron-irradiated structures


PATENT SPECIFICATIION 785,876 Inventors:-EDWARD LIONEL ASHLEY, JAMES WILFRED ASHLEY, HARRY WHALLEY BOWKER, ROBERT HUGH HALL, and JAMES WILLIAM KENDALL. D)ate of fiiinq Comnlete Specificationl: llarch 9, 1950. 1 7,i fl,-nb,If-A O 10 ( 10 x-, t Md 1,10 f({)o Yt t 1 ")pecpiccition, Ptibliqhed: Nov 6 19: U O e e Index at Acceptance:-Classes a 9 ( 4), P 30; and 87 ( 1), B 1 A( 1 A: 3 B), Bl F( 1 B:2 X)t En International Classification:-E Ogc G 21. COMPLETE SPECIFICATION. Improvements in or relating to Neutron-lxradjated Structures. We, UNITED KINGDOM ATOMIC ENERY AUTHORITY, of London, a British Authority, do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement: This invention relates to neutronirradiated graphite structures such as are required in nuclear reactors and has for an object to provide a massive structure assembled from graphite blocks, which is stable in a neutron field despite pronounced Wigner growth in the blocks. Wigner growth is the physical expansion or change of shape of a material exposed to a neutron flux In massive structures of graphite in which the Wigner effect is pronounced, the establishment of an intense neutron flux leads to swelling an expansion which introduce design difficulties in the erection and utilisation of the structure. A characteristic of Wigner growth in graphite is that it tends to differ in different directions through the material However, blocks of graphite may be shaped with respect to the grain or texture so that the longitudinal growth in a uniform neutron field is the same for all blocks If the length dimersion of the block is chosen to coincide with

the direction of minimum Wigner growth in the graphite, the longitudinal growth is also a minimum for the graphite. In one aspect of the invention, strings of graphite blocks, having minimum Wigner growth properties in their longitudinal directions, stretch respectively through the width, breadth and height of the structure and lPricedetermine its overall dimensions Each string locates along its own length the neighbouring strings transverse to it, so that changes in the width and thickness of the individual strings have little or no effect on the overall dimensions Thus although the material is anisotropic in its Wigner growth, the structure has a linear expansion which is independent of direction It expands uniformly in a uniform field and its volume expansion in a given field is determinable. The structure of the invention in one form comprises a framework or skeleton of vertical columns and horizontal cross members pinned or otherwise jointed together so that each column and cross member locates along its own length the members transverse to it. The members, if they do not extend individually from one face of the structure to the opposite face, are butted or otherwise joined together in strings to make up the total length between the faces, the interposition of any transverse member in the make-up of this total length being avoided. Changes in lateral dimensions of the members then have no effect on the overall dimensions of the structure and it becomes possible to design the structure on the basis of a known Wigner growth effect independent of direction through the structure The spaces in the framework or skeleton so formed are filled with packing blocks having clearances permitting their free growth. Alternatively the members of the skeleton or framework may be closely spaced, i e. with clearances between them only sufficient to permit the lateral Wigner growth, so that a substantially solid mass is formed by the structural members themselves. W l: V 0 z cl -A M) 785,876 The invention will be further described with particular reference to graphite structures for uranium-graphite piles although it is also applicable to structures of graphite a associated with a neutron source other than a uranium-graphite pile It is applicable for example to a fissile-producing graphite thorium mass in which a neutron flux is set up by means of a fast fission reactor. In a uranium-graphite pile arranged for the maintenance of a chain-fission reaction, there is required a large mass of graphite with channels through it for the introduction of the uranium serving as nuclear fuel and for the passage of a cooling fluid Under the large

and non-uniform neutron flux resulting from the nuclear reaction the graphite mass tends to become distorted due to the growth in dimensions known as the Wigner effect and this distortion may set a limit to the power level of operation since the shape of the mass and of the channels in it must be kept within operating limits. 2 When graphite is produced by extrusion 2 a or otherwise to have a pronounced grain, it is found that the Wigner growth is transverse to the grain, the growth along the grain being relatively small The growth along the grain after prolonged exposure is in fact less than the thermal expansion experienced in bringing a pile up to iis stable operating temperature and may be negative. The graphite thus exhibits an apparently two-dimensional Wigner growth. The structure of the invention in one form comprises graphite blocks in superposed horizontal layers, the blocks of each layer being tied together with spaces between them and orientated to have horizontal Wigner growth Preferably the ties are strips of graphite with transverse Wigner growth, disposed horizontally along lines crossing at vertical axes of the blocks The blocks are preferably rectangular with a larger or length dimension transverse to the directions of Wigner growth, and so are stood on end to provide for horizontal growth. In the application of the invention in this form, graphite blocks are arranged in layers one upon another with the graphite grain vertical so that the Wigner expansion is horizontal Spaces for taking up the expansion are left between the blocks of each layer, and horizontal ties, in the form of graphite strips cut along the grain, are arranged to bridge the spaces The blocks are preferably rectangular and of length along the grain equal to several times the width dimension; they are stood on end and the graphite strips extend between the layers in grooves cut in the end faces of the blocks. Graphite structure for a uranium-graphite pile embodying the invention will now be described by way of example and with reference to the drawing accompanying the Provisional Specification (hereinafter referred to as Fig 1) and to the accompanying drawings (Figs 2 and 3) The drawings are isometric views 70 Referring to Fig 1 the main components of the graphite structure are similar graphite blocks 1 of a width equal to the desired lattice spacing of the uranium and of a length approximately equal to a whole 75 number of lattice spacings In the structure illustrated the lengths of the blocks are somewhat less than four lattice spacings and packing blocks 2 are introduced as described in more detail hereinafter The thickness SO of the block 1 is of the same order as the width and will be in the ensuing description taken as equal to the width.

Each of the blocks 1 is formed so that the grain of the graphite extends along its 55 length; it is machined to a close tolerance; it has rectangular grooves 3, 4 cut normal to each other across each of its end faces. The graphite structure comprises a series of horizontal layers of the blocks 1 To go form eacbi layer the blocks are stood vertically and side by side with narrow spaces 5 between them Strips 6 and 7 of graphite, cut, like the blocks 1, to have the graphite grain extending along the length of the 95 strip, are laid in the end grooves 3, 4, appearing in the top surface of the layer. The strips are preferably of length equal to two block widths, each strip bridging three blocks and butting against strips normal to 100 it The next layer is then built up by stacking further blocks 1 vertically upon the respective blocks 1 of the preceding layer, the grooves in the further blocks fitting over the strips 6 and 7 105 The upper blocks rest either directly on the lower ones, or, as shown, on packing blocks 2 interposed between the layers The grooves 3 and 4 are cut deeply enough to permit vertical expansion of the strips 6 110 and 7. Prior to assembly of the structure, additional holes and grooves are formed in the graphite blocks as necessary to serve as fuel carrying cooling channels 8, as holes 9 115 for the insertion of thorium and other material to be irradiated, as holes 10 for control rods and as holes 11 for shut off rods. Although in the drawing, only two columns of fuel channels 8 are shown, such channels 120 will normally be distributed across the whole section of the structure except for peripheral portions which are to serve only for neutron reflection. For the fuel channels 8, grooves 12 are 125 cut across opposite sides of the blocks 1 so that in the assembled structure the cooling channels are circular with flat keyways and are spaced one block-width apart. In the structure illustrated, the blocks 1 1130 fuel channels 8 remain straight but suffer a small contraction in width which is greatest in the central regions of the structure The effect of this change on the rate of heat removal can be compensated by normal 70 control of the coolant pressure The coolant velocity gradient resulting from the nonuniformity of contraction is advantageous in that it tends to reduce the fuel temperature gradient through the pile 75 Butting of the ties 6 and 7 as described and shown introduces Wigner growth in the length of each string of ties because each string-length includes several thicknesses of the ties crossing it This growth can be 80 made small by employing thin ties It can be further reduced by adopting a tie lattice of larger mesh with subsidiary lattices in each mesh If

such expedients are inadequate for a particular size of structure 85 and neutron field intensity, halved joints instead of butt joints may be used, so that each string consists solely of ties in end-toend contact and consequently exhibits negligible Wigner extension 90 Alternatively, instead of ties at the ends of thne blocks 1, plugs or inserts such as dowel pins may be set in the blocks to hold their axes in fixed relation to each other A dowelled structure of graphite blocks 13 95 (drawn as though transparent) and dowels 14 in grooves 15 and holes 16 is shown in Fig 2 (only one dowel 14 being shown). The dowel pins 14 abut one another at their ends but are initially loose-fitting in the 100 grooves 15 and holes 16 The direction of minimum Wigner growth in the dowels 14 is along their lengths. Another graphite structure embodying the invention is shown in Fig 3 and comprises 105 elongated blocks 17 stretching horizontally and being individually supported on racks provided by vertical columns 18, the spacing between the blocks being sufficient to allow free lateral growth The vertical columns 110 are themselves held in fixed spaced relation by the horizontal blocks Further horizontal spacers transverse to the blocks may be provided The several members are all cut to have lateral growth ineffective upon the 115 overall dimensions of the structure.


* GB785877 (A)

Description: GB785877 (A) ? 1957-11-06

Improvements in or relating to the surface treatment of aluminium



ES213758 (A1) ES213758 (A1) less Translate this text into Tooltip



PATENT SPECIFICATION Inventors: PETER ROBERT WILLIAM Sl a I-I and T 4 ICHAEL ROGER PESTELL god Be Date of filing Complete Specification Feb 17, 1954. Application Date Feb20, 1953 No i l tg) Cornplete Specification Published Nov6, 1957. Iivdex at Acceptance:-Class 's 2 ( 2), E 3, U 4 (i: E 3: F 12 HI J: M 1), U 7 A. International Classification: -SC 23 f, g. COMPLETE SPECIFCATION Improveme Ents in or reilating to ithe Surface Treatment of Aluminium We, ACORN ANODISING COMPANY LIMITED, a company registered under the laws of Great Britain, of Callard House, 74 A, Regent Street, London, W 1, 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 the surfaae treatment of aluminium of varying degrees of purity, and of articles made therefrom, to produce a bright lustrous metallic appearance. It is known that mechanical polishing or buffing operations do not produce the best results when applied to the surfaces of aluminium and its alloys and other processes are in use, known as " brightening processes " whereby the specular reflectivity of these surfaces may be greatly improved by electrochemical treatments It has also been proposed to brighten aluminium or aluminium alloy surfaces by purely chemical treatments, such as by immersing the articles in acid baths The baths employed in these chemical brightening processes have consisted of a mixture of concentrated phosphoric, nitric and sulphuric acids; or a similar mixture containing, in addition, a weak acid, e g, boric acid, which forms a complex with the phosphoric acid; or relatively dilute aqueous solutions containing nitric acid, hydrofluoric acid, chromic acid and either ammonia, a salt of a metal

more electropositive than aluminium, or both ammonia and phosphoric acid. The object of the present invention is to provide an improved chemical brightening process for the surface treatment of aluminium wvvhich shall produce bright lustrous metallic surfaces which are better than those that can be obtained by mechanical means and approach the excellence of those that can be obtained by electro-chemical brightening processes, while being cheaper to operate and not requiring the use of mechanical and electrical equipment, According to this invention, a chemical brightening process for the surface treatment of aluminium to produce a bright lustrous metallic surface thereon comprises the step of contacting the aluminium surface with an aqueous solution containing hydrofluoboric acid, nitric acid and a soluble salt of a metal which is displaced in solution by aluminium. The aqueous solution is preferably a relatively dilute solution, at least so far as the hydrofluoboric acid is concerned For example, its content of this acid may be in the range of from 0 15 % to 5 % by weight (calculated as 42 % W/w hydrofluoboric acid), its content of nitric acid (calculated at a specific gravity of 1 42) may be in the range of from 0 25 % to 30 % by weight, and its content of the soluble salt may be in the range of from 0.01 % to 0 3 % by weight In general, the proportion of nitric acid in the solution must be in the region of 10 % to 30 % when aluminium of very high purity is to be treated. Hydrofluoboric acid in all but very dilute solutions appears to attack aluminium by etching it but the addition of nitric acid and the soluble salt of a metal which is displaced in solution by aluminium considerably reduces the attack upon the aluminium and results in a smoothing action being obtained Soluble salts of metals such as copper, zinc silver or cadium may be employed with advantage. Additions to the treatment solution of boric acid, acetic acid, phosphoric acid, ammonia or ammonium salts appear to improve the specular quality of the finish produced on the articles dipped therein Additions of glycerol. glycols or ethers of the alkylene glycols appear to have a similar effect but, owing to the presence of the nitric acid, it may be that it is their oxidation products which are responsible. Some typical and preferred aqueous baths 785,877 i 873153. D' p for the surface treatment of aluminium in accordance wth this invention are made up as follows, all percentages being by weight:FOR ALUMINIUM OF 99 % TO 99 7 % PURITY (a) 2 % of 42 % hydrofluoboric acid. 1 % of glacial acetic acid. 1.5 % of nitric acid (S G 1 42). 0.2 % of copper nitrate.

Operating temperature 950 C. (b) 5 G% of glycerol. 4 % of 42 % hydrofluoboric acid. 3 % of nitric acid (S G 1 42). 0.5 % of boric acid. 0.2 % of copper nitrate. Operating temperature 85 -95 C. (c) 3 % of 42 % hydrofluoboric acid. 2.5 to 3 % of nitric acid (S G 1 42). 1 % of ammonia. 2 % of ethylene glycol mono-ethyl ether. 0 2 % of copper nitrate. Operating temperature 850-950 C. (d) 3 % of 42 % hydrofluoboric acid. 2 to 2 5 % of nitric acid (S G 1 42). 2 % of ethylene glycol di-ethyl ether. 0 2 % of copper nitrate. Operating temperature 800-95 C. (e) 1 % of 42 % hydrofluoboric acid. 0.4 % of nitric acid (S G 1 42) 0.01 to 0 3 % of copper nitrate. Operating temperature 80 -100 C. (f) 0 5 % of 42 %' hydrofluoboric acid. 3 % of nitric acid (S G 1 42). 0.01 to 0 3 % of copper nitrate. Operating temperature 80 -100 C. (g) 0 5 % of 42 % hydrofluoboric acid. 11 % of nitric acid (S G 1 42). 0.01 to 0 3 % of copper nitrate. Operating temperature 80 -100 C. FOR ALUMINIUM OF 99 7 % To 99 99 %/o PURITY (h) 0 2 to 0 3 % of 42 % hydrofluoboric acid. % of nitric acid (S G 1 42). 0.01 to 0 3 % of copper nitrate. Operating temperature 85 -100 C. (i) 0 2 to 0 3 % of 42 % hydrofluoboric acid. % of nitric acid (S G 1 42). 0.01 to 0 3 % of copper nitrate. Operating temperature 80 -100 C. (j) 0 25 % of 42 % hydrofluoboric acid. % of nitric acid (S G 1 42). up to 2 % of phosphoric acid (S.G 1 75). 0.01 to 0 3 % of copper nitrate. Operating temperature 80 W-100 ' C. The period of immersion of the aluminium articles varies somewhat with

the nature of the bath employed but is generally comprised in the range of from 2 to 10 minutes. Although it is desirable that the articles to be treated should be free from grease and oil, careful degreasing is not essential. In some cases a smut of copper may be apparent on the surfaces of the articles when they are withdrawn from the bath but this 65 may be removed by immersing the articles for a brief period in any suitable acid bath, for example, nitric acid of from 5 to 50 % strength. After treatment, the articles may be washed 70 in water, dried and used without further treatment Alternatively, they may be lacquered or anodised and dyed, if a bright coloured finish be required. In general, ten gallons of one of the aqueous 75 solutions prepared in accordance with this invention will serve for the brightening treatment of approximately 8 square feet of metal surface but a decrease in the brilliance of the effect produced is perceptible towards the end 80 The bath can be regenerated by adding hydrofluoboric acid to the extent of 50 %' of the original make-up and nitric acid (and acetic acid, where used) to the extent of 20 of the original make-up 85 Three such regenerations may usually be effected but thereafter the increase in the amount of aluminium in solution causes a slow decrease in the brilliance of the effect produced which cannot be satisfactorily remedied 90 by further additions of acids. The presence of even small amounts of sulphuric acid or sulphates is found to be objectionable but these unwanted substances may be removed by addition of suitable amounts 95 of barium acetate In prpctice it is found that a standard addition of two grammes of barium acetate per galon of made up solution will precipitate all sulphates normally present as impurities in the chemicals and water used for 10 (' the make up.


* GB785878 (A)

Description: GB785878 (A) ? 1957-11-06

A method of carrying out industrial processes in a glow discharge



BE526527 (A) CH314340 (A) DE976529 (C) FR1097674 (A) NL83318 (C) US2955998 (A) BE526527 (A) CH314340 (A) DE976529 (C) FR1097674 (A) NL83318 (C) US2955998 (A) less Translate this text into Tooltip



PATENT SPECIFICATION 785,878 Date of Application and filing Complete Specification: Feb 16, 1954. No 4499/54. Application made in Switzerland on Feb 17, 1953. Complete Specification Published: Nov 6, 1957. Index at acceptance:-Classes 39 ( 1), D( 8: 12 86: 12 C: 17 D: 38), 1; 39 ( 3), H( 1 GX: 2 A); and 82 ( 2), V( 2 M: 4 K). International Classification:-C 23 c H Olj H 05 b, f. COMPLETE SPECIFICATION A method of Carrying Out Industrial Processes in a Glow Discharge I, BERNHARD BERGHAUS, of German Nationality, sole proprietor of the firm ELEKTROPHYSIKALISCHE ANSTALT BERNHARD BERGHAUS, of Vaduz, Liechtenstein, do hereby declare this invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: - The use of the glow discharge for industrial processes, such as hardening, annealing, metallisation and carburisation in metallurgy, and in synthetic processes, with gasses and liquids, such as the production of ammonia, is already known.

After many years of investigations the inventor of this application has, according to the present invention, succeeded in further improving the efficiency of the glow discharge process The invention relates to a method of carrying out industrial processes in glow discharges, such as annealing, hardening, nitriding, carburisation, metallisation, and chemical processes, such as the production of ammonia in which the energy of the glow discharge is increased in a predetermined part of the discharge space as compared with other Darts thereof. The term 'cathode' as used throughout this specification and the appendent claims should be construed as including electrodes which are operated at least at intervals as cathodes. The invention consists of a process for carrying out metallurgical, chemical and other industrial processes in a glow discharge using at least two cathodes, characterised in that the energy of the glow discharge between two cathodes is increased by choosing the distance between the two cathodes so that the glow fringes on the two cathodes overlap, but so that the dark spaces covering the two cathodes do, not overlap. The energy of the charge carrier is thus better utilised and the efficiency of the discharge is increased in that the escape of the charge carriers into the vacuum chamber space is prevented and the same have a greater effect on the work-pieces connected up as cathodes In contrast with the present 50 invention there is the known hollow cathode effect, referred to in the literature as being detrimental and to be avoided in all circumstances. In carrying the invention into effect work 55 pieces may be connected up as cathodes. Thus the work-pieces may be either connected together directly so that they have the same negative potential, or they may have imparted to them the same or approximately 60 the same potential, for instance by separate electric leads introduced into the discharge vessel Preferably the work-pieces are given negative potentials but the process may also be carried out with alternating potentials 65 when the work-pieces will be periodically operated as cathodes. The process may also be carried out using cathodes operated as such during alternating intervals so that the glow fringe of one ot tie 70 cathodes is formed at a time when the glow fringe of the other cathode has not completely disappeared This is the case when the glow discharge is fed by an alternating current, if the frequency is sufficiently high 75 With a given distance between the workpieces, the proximity of the boundaries of the glow fringe is adjusted by regulating the pressure of the gas If the given distance between the work-pieces is too great to allow 80 the glow fringes to overlap by

reducing the discharge pressure, use is made of auxiliary cathodes which are sufficiently near the work-pieces to produce a glow fringe overlapping tlfe glow fringes of the work-pieces 85 Vice versa, with a given gas pressure the overlapping of the glow fringes is effected by selecting the distance between the cathodes or also by using auxiliary cathodes. Within this discharge space, which is en 90 closed by the work-pieces and auxiliary cathodes having approximately the same voltage, the transformed specific load at all surfaces is higher than at the other surfaces of the work-pieces The local concentration of energy thereby obtained in predetermined parts of the discharge space may be further assisted by suitably selecting the auxiliary cathodes with respect to their heat capacity, that is to say by suitably choosing their mass and radiating surface Thus, by relatively adjusting the surfaces and masses of workpieces and auxiliary cathodes the distribution of energy can be additionally controlled according to the requirements of the problem to be solved Thus for instance, the mass surface of the auxiliary cathodes can be made mass of the work-pieces Preferably, the auxiliary cathode is small, if for instance it has to be heated to a very high temperature in order to produce or intensify the effect of sputterring According to the invention, the surface of the auxiliary cathodes can be made small or large as compared with the surface of the work-piece In other cases it is an advantage to fit the shape of the auxiliary cathodes to the shape of the work-pieces. Thus for instance, the auxiliary cathode may partly surround the work-piece The distance of the auxiliary cathodes from the work-piece is constant according to the invention, in order to obtain uniform effects. However to obtain effects which are not evenly distributed, it may be required to have unequal distances between the workpieces and auxiliary cathodes When several work-pieces are being treated, they are preferably arranged at an equal distance from a smaller number of auxiliary cathodes In the case of work-pieces provided with hollow spaces, within which lie work-piece parts of the same potential, the overlapping of the glow fringes is effected by gas pressure regulation, for instance, in the case of tubular work-pieces If in the case of such hollow, more particularly tubular, work-pieces, the hollow space is too wide, an auxiliary cathode in the form of a wire, rod or tube is provided so that the work-piece surrounds the auxiliary cathode entirely or partly. Finally, according to the invention, in order to increase still further the ion bombardment in the gas discharge and to assist in the above-mentioned mass and surface effects on the work-pieces and auxiliary cathodes, the glow discharge can be supplied with the

maxmium energy only for periods having a duration of several seconds down to fractions of a second, between long intervals during which the glow discharge is supplied with a reduced amount of energy or the supply is interrupted This production of energy pulses may be effected by supplying the electric energy intermittently, or by changing the discharge pressure, for instance in such a manner that the gas pressure is increased to such a value that a discharge of great energy no longer takes place between the work-pieces A similar eftect can De ootained winii a reduction in the gas pressure. Preferably, the process according to the invention is used in the case of gas pressures 70 which are higher than those usually employed in glow discharge processes for instance gas pressures of one mm Hg and more. Applications of the process of tile inven 75 tion will now be described, by way of example, in connection with the production of a coating of high melting metal on a workpiece. Figure 1 of the accompanying drawing 80 shows diagrammatically a glow discharge apparatus 1 consisting of a base 3 and a removable cover 2 An electric lead 4 passes through the base 3 and is connected to a tubular work-piece 5 A rod-like auxiliary 85 cathode 7 which acts as the source of coating metal is maintained in the interior of the said tubular piece by means of a support 8 The tube 5 and the auxiliary cathode 7 are at the same cathode potential whilst the base-plate 90 of the vessel is used as an anode The inner surface 6 of the tube 5 and the rod 7 are covered by a glow so that one glow fringe encircles the other According to the invention, the glow fringes are so controlled by the ad 95 justment of the gas pressure that finally they overlap The gas pressure must not be reduced so much that the dark spaces covering the parts 6 and 7 overlap The process is easily controlled and an increase of the dis 100 charge energy is obtained Thus, it was possible to obtain, by using hydrogen at a pressure of 2 5 mm Hg, a tube of 20 mm. diameter, and a tungsten rod of 2 mm diameter, during a testing period of 20 hours, a 105 deposition of tungsten of 0 1 mm thickness upon the inner surface 6 of the tube 5 An electric power of 20 to 100 Watts per cm sq. was used On the other surfaces of the treated tube only a fraction of this power ap 110 peared and the concentration of the energy had its full effect upon the desired parts The work-piece is cooled off by losing heat by radiation and could thereby be maintained at a moderate temperature, whilst the tungsten 115 rod could be heated up to its fusing temperature. Figure 2 is a cross-section through the iron tube 5 with the centrally arranged rod 7 The inner surface covered with tungsten is indi 120

cated by 6. Figure 3 shows the arrangement for treatment of a turbine blade 9 The blade is to be provided on its front edges with a coating of tantalum which is diffused in and there 125 fore adheres and is corrosion and heat resistant There is arranged opposite this thick part of the turbine blade 9 a tantalum sheet 10, acting as an auxiliary electrode. The width of the space 12 is small enough to 130 785,878 terised in that the glow fringe of the one cathode is formed at a time when the glow fringe of the other cathode has not corm 45 pletely disappeared.


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