Variable Spring Supports & Hangers

Overview

Variable Springs are used to support piping which is subject to thermal expansion and other factors that may cause the pipe support point to shift. The force of spring varies through the range of travel, hence the name “Variable Supports”.  As the supported structure moves upward the force exerted by the spring decreases while the opposite occurs during downward movement.

Variable supports are typically installed where thermal movements cause the system’s position and dimensions to change; however, if the variability surpasses 25%, Rilco recommends our Constant Supports or the Rilco Cam Roller Constants.

All of the Rilco spring units are designed to meet or exceed the requirements of the ASME Code for Pressure Piping, ASME B31.1, B31.3, and MSS SP-58.

Constant Catalog 

     View our Variable & Constant Spring Catalog for complete specs.

Selecting the Correct Variable Spring

In order to manufacture a variable spring, some of the following data will need to be known:

One of the first 5 conditions in the chart below must be met (condition 6 is used to obtain pricing only)

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
Variable Spring Hangers and Supports.pdf

Information needed for Ordering

  • One of the conditions mentioned in the above chart (selecting the correct spring)
  • Preferred spring housing final coating/finish
  • Any parts that are not Rilco standard (Example: lifting lugs)

Spring Types

Drawing Rilco Type Description
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 Single-Lug Hanger Type Support:  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 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 Hanger-Type Support:  Designed for use where variable spring hanger is   positioned above supporting structure with spring   adjustment made from the top.
E Hanger-Type Support:  Designed for use when spring adjustment must be   below the structure on which the spring housing is being   supported.
F Base-Type Support:  Designed for supporting piping from below.
G Hanger-Type Support:  Designed for use where headroom is limited or where an   obstruction prohibits the use of a single spring hanger.

 

Variable Spring Hangers and Supports.pdf

Figure Numbers/Sizes and Grinnell Equivalents

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
Variable Spring Hangers and Supports.pdf

Load Table

SpringSize 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
Variable Spring Hangers and Supports.pdf

Finish

Finish or coating on the spring housing is dependent upon the environment in which the springs are installed. 

Possible Finishes Include:

  • Black
  • Plated
  • Hot-dipped Galvanized

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.
Variable Spring Hangers and Supports.pdf

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
Variable Spring Hangers and Supports.pdf