Pipework and/or vessels subject to temperature change or subsidence, etc. which give rise to vertical displacements should be supported by a resilient device which will absorb/accommodate the movement. For relatively small displacements (up to about 75mm) the variable spring support is recommended. The Carpenter & Paterson standard
range of variable spring supports are produced in four basic travel ranges; 35mm, 70mm,140mm and 210mm. These are designated DV35, DV70, DV140 and DV210 respectively. The travels stated are the "maximum working range of the springs. This full travel can be used providing the necessary calculations are carried out to ensure that the connecting equipment and pipework can withstand the large load changes that occur during pipe movement. Most national standards do limit the load variation to maximum of 25%. It is therefore usual to select variable spring supports on this basis.
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