Date post: | 03-Apr-2018 |
Category: |
Documents |
Upload: | mohan-varkey |
View: | 223 times |
Download: | 0 times |
of 17
7/28/2019 Variable Springs Catalogue
1/17
Variable SpringSupports
Section 2
7/28/2019 Variable Springs Catalogue
2/17
Variable spring support units are devices used to support pipework which is subject tovertical displacement because of temperature changes or subsidence. It isrecommended that a variable spring support unit only be used when the load variation
is less than 25% from cold to hot load and that the displacement is small, up to 50 mm.Where the conditions are out of this criteria a QUALITY PIPE SUPPORTS constantspring support should be considered. Practical and technical advice is available fromQUALITY PIPE SUPPORTS.
All units are pre-set to their cold load. Each unit will have been checked through its totalworking range and its required working range. The variable spring unit will be tested ona specialised test rig which is calibrated back to a national standard.
The variable spring support finish is available as follows:
Hammer finish paint Hot dip galvanised Customer specific paint finish.
Spring coils are plastic coated on standard galvanized units.
Q.P.S. variable spring units are produced in high quality carbon steel, but we are ableto offer units from austenitic stainless steel and various alloy steels where required.
Where a spring unit is required which is not covered by the Q.P.S. range, our technical
department will design a unit for your particular requirement.
All Q.P.S. variable spring support units are capable of supporting pipework that can besubjected to hydrostatic test loads up to two times the working load of the unit.
ORDERING
When ordering please specify:1. Q.V. number, e.g. (Q.V. 2)
2. Model, e.g. (A, B, D etc.)
3. Size (taken from selection table)
4. Thread details
5. Vertical movement and direction of movement, e.g. cold to hot, 16 mm up
6. Preset load (Q.P.S. can calculate this for you given the information as above)
7. If Hydrostatic stops are required
8. Protective finish
9. Marking (identification) number10. Distance between rod centres and total load for model G.
Page 31
DESCRIPTION
7/28/2019 Variable Springs Catalogue
3/17Page 32
HOW TO SELECT THE APPROPRIATE VARIABLE SIZE (0-22)INFORMATION NEEDED:SUPPORTED LOAD = Load calculated when pipe is in the hot position
including insulation, contents, weight of pipe andancillary equipment.
INITIAL SELECTION = Select size by plotting load in table.TRAVEL UPOR = Distance pipeline moves and in what direction.TRAVEL DOWNPRESET LOAD = Calculate by multiplying the spring rate from the table
by the TRAVEL UP (+) or TRAVEL DOWN (-) and addingto SUPPORTED LOAD.
Example Size 8 Supported Load = 366 kgQV1 Travel Up 3mm
x Spring Rate 5.4 = 16.2 kgPreset Load = 382.2 kg
SELECTION PROCEDURE:After initial selection in the support table and calculation of preset load check the preset load and
travel are within range shown for size.Then check load change at cold position is within 25% of hot load as follows:
PRESET LOAD 382.2x 100 (using the above example) x 100 = 104.4%
SUPPORTED LOAD 366
Acceptable, if not rework calculations using QV2 or QV3. Spring rates if still not within 25%consider constant load support. Look up 366 Kg in table, located in Column 8 (Spring Size), movedown 3mm as travel is up, to check still within working range. If it is then size is correct, if not,move up or down a size and repeat selection.
EXAMPLE WHERE FIRST SELECTION IS INCORRECT:
Supported Load = 366
Travel Up 50mm Preset Loadx Spring Rate 5.4 = 270 = 173%
Supported LoadPreset Load = 636
TRY QV3
Supported Load = 366
Travel Up 50mm Preset Load 431x Spring Rate 1.3 = 65 = 118%
Supported Load 366
Preset Load = 431
Acceptable and within range so selection would be QV3 Size 8 Preset Load 431, Hot Load 366.
NOTE: The preset load is in over travel, which is acceptable in this case. Do not select when hotload is in over travel. The supports have been designed to perform best inside the working range.
TO CALCULATE ROD TAKE OUT:
Look up minimum rod take out in the table for model size and type selected, this is the dimensionin the minimum load position. Then determine on working range scale where the preset load ispositioned or add to dimension shown in tables, using the above as an example.
QV3 say Model A Size 8 look up table = 463mmPreset Load at 431 read on scale = 141mmRod take out = 604mm
TO CALCULATE LOADED LENGTH OF MODEL F:
Look up maximum loaded length in table for model, size and type selected. Then determine onworking range scale where preset load is positioned and subtract from dimension shown.
Example QV2 Size 16 Present Load = 3506.5 KgMaximum dimension from table = 543mmPreset Load read on scale at 42Loaded length 501mm
SELECTION PROCEDURE
7/28/2019 Variable Springs Catalogue
4/17Page 33
Variable Spring SupportsDiagrams and Tables
7/28/2019 Variable Springs Catalogue
5/17
7/28/2019 Variable Springs Catalogue
6/17
7/28/2019 Variable Springs Catalogue
7/17
Page
36
O
W A
LOADED
LENGTH
Y
P.C.D.
W
MODEL
A
SEE MODEL F FO
MODEL H
OTHER DETAILS
RADIUS T
CUSTOME
REQUIRE
ROD
TAKE
OUTA
O
W
D DIAB
T
C
Rod Take Out
(at Load Position)
TLOAD FLANGE
(P.T.F.E. SLIDER OPTIONAL)
MODEL B
BEFORE SELECTING THE SIZEWORKING LOAD MUST BE HALVEDNOTE : ON TYPE G UNITS THE
O
W
D DIA
ROD
TAKE
OUT
W
MODEL FMODEL A
MODEL E
O
ROD
TAKE
OUT
A
W
MODEL GREQUIRED
X
N
AROD
TAKE
OUT
VARIABLE SPRING SUPPORTS
FIG. QV1
7/28/2019 Variable Springs Catalogue
8/17
7/28/2019 Variable Springs Catalogue
9/17
Page
38
O
W A
LOADED
LENGTH
Y
P.C.D.
W
MODEL
A
SEE MODEL F FOR
MODEL H
OTHER DETAILS
RADIUS TO
CUSTOME
REQUIREM
ROD
TAKE
OUTA
O
W
D DIAB
T
C
Rod Take Out
(at Load Position)
TLOAD FLANGE
(P.T.F.E. SLIDER OPTIONAL)
MODEL B
BEFORE SELECTING THE SIZEWORKING LOAD MUST BE HALVEDNOTE : ON TYPE G UNITS THE
O
W
D DIA
ROD
TAKE
OUT
W
MODEL FMODEL A
MODEL E
O
ROD
TAKE
OUT
A
W
MODEL GREQUIRED
X
N
AROD
TAKE
OUT
VARIABLE SPRING SUPPORTS
FIG. QV2
7/28/2019 Variable Springs Catalogue
10/17
7/28/2019 Variable Springs Catalogue
11/17
O
W A
LOADED
LENGTH
Y
P.C.D.
W
MODE
A
SEE MODEL F FO
MODEL H
OTHER DETAILS
RADIUS T
CUSTOM
REQUIRE
ROD
TAKE
OUTA
O
W
D DIAB
T
C
Rod Take Out
(at Load Position)
TLOAD FLANGE
(P.T.F.E. SLIDER OPTIONAL)
MODEL B
BEFORE SELECTING THE SIZEWORKING LOAD MUST BE HALVEDNOTE : ON TYPE G UNITS THE
O
W
D DIA
ROD
TAKE
OUT
W
MODEL FMODEL A
MODEL E
O
ROD
TAKE
OUT
A
W
MODEL GREQUIRED
X
N
AROD
TAKE
OUT
Page
40
VARIABLE SPRING SUPPORTS
FIG. QV3
7/28/2019 Variable Springs Catalogue
12/17
7/28/2019 Variable Springs Catalogue
13/17
O
W A
LOADED
LENGTH
Y
P.C.D.
W
MODE
A
SEE MODEL F FO
MODEL H
OTHER DETAILS
RADIUS T
CUSTOM
REQUIRE
ROD
TAKE
OUTA
O
W
D DIAB
T
C
Rod Take Out
(at Load Position)
TLOAD FLANGE
(P.T.F.E. SLIDER OPTIONAL)
MODEL B
BEFORE SELECTING THE SIZEWORKING LOAD MUST BE HALVEDNOTE : ON TYPE G UNITS THE
O
W
D DIA
ROD
TAKE
OUT
W
MODEL FMODEL A
MODEL E
O
ROD
TAKE
OUT
A
W
MODEL GREQUIRED
X
N
AROD
TAKE
OUT
Page
42
VARIABLE SPRING SUPPORTS
FIG. QV4
7/28/2019 Variable Springs Catalogue
14/17
7/28/2019 Variable Springs Catalogue
15/17Page 44
INSTALLATION INSTRUCTIONS
QUALITY PIPE SUPPORTS
VARIABLE SPRING UNITSVariable Spring Units are pre-set to a cold load position before despatch from our works.
The pipe system being supported in service would be either :
(a) dry system
(b) wet system
In the event that the system is 'dry' in service but has to undergo a hydraulic test prior to
service the spring units should be ordered with down travel hydrostatic test stops which
would remain in position until the hydraulic test has been carried out.
In the event that the system is 'wet' in service then the standard pre-set stops which set theunits to 'wet load' are all that is necessary.
Once removed the pre-set stops on all units should be retained in case of a requirement for future
use. If it becomes obvious that an incorrect load is being applied to any supports in the system it
is advisable to contact our sales support team who would be pleased to give advice.
To Install Spring Units - Type A,B,C.
The spring unit is fitted between the Pipe/Duct/Bracket to be supported and the steelwork
above the unit. The hanger rod coming up from the Pipe Clamp/Duct/Bracket is connected to
the turnbuckle which is fitted to all these types of spring units.
Rotation of the turnbuckle transfers the pipe load to the spring unit thus allowing withdrawal
of the pre-set stops. No further adjustment should be required unless it becomes obvious thatincorrect loads are being applied to supports in the system.
To Install Units Type D and E.
Both of these units are mounted on top of the steelwork.
Type D
The hanger rod passes through the unit and is secured to the spring unit at the top of the load
tube by 2 nuts.The hanger rod should be of adequate length and threaded sufficiently to take
into account any deviation in pipe or duct elevation since these units are not supplied with a
turnbuckle. Adjustment of the 2 nuts transfers the load to the spring unit thus allowing
withdrawal of the pre- set stops.
Type E
The hanger rod passes through the Spring units and is secured with 2 nuts which prevent it
passing through the Spring pressure plate. Adjustment in length is provided by a turnbuckle
at a convenient situation in the hanger assembly.
Rotation of the turnbuckle transfers the load to the spring unit allowing withdrawal of the pre-
set stops.
To Install Spring Units Type F, H & K
These units are base mounted and should be aligned directly below the point of support. Theheight of the load flange is adjusted to contact the lower surface of the support point by
rotation of the adjustment nut on the load column. Further rotation of this nut will transfer the
load onto the Spring unit and the pre-set stops can then be withdrawn.
INSTALLATION INSTRUCTIONS
7/28/2019 Variable Springs Catalogue
16/17Page 45
To Install Spring Units Type F(A)
These units are base mounted and should be aligned directly below the point of support. The
height of the load flange is adjusted to contact the lower surface of the support point by
rotation of the adjustment nut on the load column. The lower of the two sets of "Red Painted"
adjusting nuts(A) can be wound clear of the pressure plate at this time, or after the HydrostaticTest (if required) has taken place. Further rotation of the adjustment nut on the load column
will transfer the load onto the spring unit. The upper of the two sets of "Red Painted" adjusting
nuts (B) can then be wound clear of the pressure plate.eg.(towards the locknut(C)).
To Install Spring Units Type G
The units are fitted with turnbuckles so that the hanger rods which having been previously
connected to the steelwork above can be inserted into them. The rotation of the turnbuckles
transfers the load to the spring units. When the load is correctly supported the pre-set stops
can be withdrawn.
Inspection During Operation
Shortly after commissioning the support should be examined to ensure correct travel has
been achieved in the hot position. If the load plate is against the stop at either end of the scale
an investigation should be made at once. Subsequently the support should be examined at
regular intervals to ensure no change has occurred either in application or condition. The
frequency of examination intervals will depend on the environmental and operating
conditions and will range from annual examinations for land based dry atmospheres to
maybe monthly frequency in hostile offshore conditions with the possibility of salt
contamination.
MaintenanceIf an excessive build up of foreign matter or corrosion is observed it is important that the
Spring support is cleaned either by hand or with a pressure washer to ensure uninhibited
operation.
INSTALLATION INSTRUCTIONS
7/28/2019 Variable Springs Catalogue
17/17
NOTES