Rilco Manufacturing

Products > Variable Springs
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Selecting A Correct Spring | Spring Types | Figure Numbers/Sizes | Load Table | Specifications | Finish | Terminologies | Formulas/Calculations | Ordering | FAQs

General Information:
Variable springs are designed for supporting pipes, vessels and pipe structure connections to large tanks.

The word "variable" refers to the fact that the load-carrying capacity of the spring varies considerably as the spring is compressed or expanded from a fixed reference point. In other words, as the pipe moves up, the spring is expanded and the load that it exerts is decreased. The opposite effect is experienced when the pipe moves down. In either case, the exerted load must not vary more than 25% of the calculated load.

Recommended Services:
Install on pipeline subject to...
  • Thermal movement.
  • Vertical movement not to exceed 3 inches or 75 millimeters.

Selecting A Correct Spring:
In order to manufacture a spring, the following data must be known -
  • Part No.
  • Size
  • Type
  • Operating load or Hot load
  • Installed load or Cold load
  • Movement and its direction
Since some of above data can be derived from the others, all are not needed. One of the below conditions must be provided in order to manufacture a spring:
Condition Known Unknown
1 Part No., Size, Hot load, Movement & Direction Cold load
2 Part No., Size, Cold load, Movement & Direction Hot load
3 Hot load, Movement & Direction Part No., Size, Cold load
4 Cold load, Movement & Direction Part No., Size, Hot load
5 Hot load, Cold Load & Spring rate Part No., Size & Movement
6 Figure, Size, Type  Hot load, Cold load, Movement & Spring rate
Note: Condition 6 is used to obtain pricing only.

Spring Types:
>Drawing Rilco Type Grinnell Equivalent Description
A A A Hanger-Type Support. Design for use where headroom is unlimited. Top of spring housing is a rod which allows the spring to attach to a support.
B B A Single-Lug Hanger Support type. Designed for use where headroom is limited. Top of spring housing has a single lug to accommodate a double-lug beam attachment from the top support.
C C A Hanger-Type Support. Designed for use where headroom is limited. Top of spring housing has double lugs to accommodate a single-lug attachment from the top support. 
D D A Hanger-Type Support. Designed for use where variable spring hanger is positioned above supporting structure with spring adjustment made from the top.
E E A Hanger-Type Support. Designed for use when spring adjustment must be below the structure on which the spring housing is being supported.
F F A Base-Type Support. Designed for supporting piping from below
G G A Hanger-Type Support. Designed for use where headroom is limited or where an obstruction prohibits the use of a single spring hanger.


Figure Numbers and Sizes:
Rilco Grinnell Equivalent
Part Number Size Figure Number Size
RVS-82 0 - 22 82 0 - 22
RVS-268 0 - 22 268 0 - 22
RVS-98 0 - 22 98 0 - 22
RVS-3X 0 - 22 Triple 0 - 22
RVS-4X 0 - 22 Quadruple 0 - 22


Load Table:
Spring Size Rod Size (in.)

Load (lb.)

Spring Rate (lb./in.)

Minimum Maximum RVS-82 RVS-268 RVS-98 RVS-3X RVS-4X
0 1/2" 50 88 30 15 7 5 4
1 74 126 42 21 10 7 5
2 95 162 54 27 13 9 7
3 123 210 70 35 17 12 9
4 165 282 94 47 23 16 12
5 221 378 126 63 31 21 16
6 5/8" 294 504 168 84 42 28 21
7 392 672 224 112 56 37 28
8 525 900 300 150 75 50 38
9 3/4" 700 1200 400 200 100 67 50
10 910 1560 520 260 130 87 65
11 1190 2024 680 340 170 113 85
12 1" 1575 2700 900 450 225 150 113
13 2100 3600 1200 600 300 200 150
14 1 1/4" 2800 4800 1600 800 400 267 200
15 3780 6480 2160 1080 540 360 270
16 1 1/2" 5250 9000 3000 1500 750 500 375
17 1 3/4" 7000 12000 4000 2000 1000 667 500
18 2" 9320 15970 5320 2660 1330 887 665
19 2 1/4" 12380 21230 7080 3540 1770 1180 885
20 2 1/2" 16450 28200 9400 4700 2350 1567 1175
21 2 3/4" 21875 37500 12500 6250 3125 2083 1563

22

3" 29173 50010 16670 8335 4167 2778 2034


Specifications:
Component Rilco Standard? Description/Comment
 Coil Yes Neoprene or powder coated & designed per MSS-SP58
 Travel stops Yes Hydrostatic & Upper stops are standard
 Metal name plate Yes Stainless steel etched with client tag, Rilco part number, size, type hot load, cold load, spring rate & movement. Loads and movements available in imperial or metric unit.
Guided load column (Type F only) No Specify guided load column when required.
 Lifting lugs No Recommended for spring weighing more than 100 lbs. or 45 kg.

Finish:
Finish or coating on the spring housing is depend upon the environment in which the springs are installed. Possible finishes are Painted (Black), Plated, or Hot Dip Galvanized. A different paint color may be available upon request.

Terminologies:
Spring Part No. Categorized by spring rate
Spring Size Categorized by load range
Spring Type Categorized by physical shape.
Hot load / Hot setting / Operating load The weight the spring has to support while the pipe line system is in operation. This is also called Operating load.. 
Cold load / Cold setting / Installed load The weight the spring has to support while the pipe line system is NOT in operation. This is also called pre-set load.
Movement / Travel The measure of a vertical travel distance of the pipe which is supported by the spring when the pipe line is in operation.
Movement / Travel direction The movement direction, either UP or DOWN of the pipe while in operation compared to its resting point (not in operation). 
Spring rate Lbs/In of spring travel
Hydro-tested load The test which determines whether the spring will support the operating load.
Travel stops Limit the spring travel at the top and bottom to a small percentage beyond the specified range. In addition, they prevent the spring from moving while the spring is not in operation (in pre-set mode) or in hydrostatic testing phrase.
Load flange Top Plate on which the pipe load rests
Variability The amount of supporting load variation on horizontal piping. The percentage of variability should not exceed 25%.


Formulas And Calculations:
Upward movement If Cold load is greater than Hot load
Downward movement If Hot load is greater than Cold load
Movement

= (Cold load - Hot load) / Spring rate.

If result > 0 then movement direction is up. Otherwise, it's down.

Variability (% load change) = ((Movement x Spring rate) / Hot load) x 100


Ordering:
The following must be provided -
  • At least one of the six conditions mentioned above (Selecting a correct spring)
  • Spring housing final coating (finish)
  • Any parts that are not Rilco standard such as lifting lugs.

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11435 Brittmoore Park Dr
Houston, Texas 77041    USA
713-466-4777
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