Variable Spring Supports
Variable spring supports, also called spring cans or variable supports, can help with the vertical displacement of a piping system. Pipework and vessels subject to temperature change or subsidence, etc., which give rise to vertical displacements, should be supported by a resilient device that will absorb/accommodate the movement. The variable spring support can help for relatively small removals (up to about 75mm). Constant supports are often used on the same piping system with spring cans. The standard range of variable spring supports produced in four primary 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 complete travel can be used, providing the necessary calculations to ensure that the connecting equipment and pipework can withstand the load changes during pipe movement. However, most international standards limit the load variation to a maximum of 25%. It is therefore usual to select variable spring supports on this basis.
In keeping with generally accepted practice, we recommend that the actual pipe load is correctly supported when the pipe is in its normal working position. A correctly supported pipe load ensures no abnormal or excessive forces due to out-of-balance supporting effort are transferred to the pipework in its stressed working condition.
Variable spring should be supplied with a galvanized finish and a plastic-coated spring coil. However, our unique design allows the internal and external surface coating to meet customer-specific requirements.
Variable spring supports are a device that absorbs/accommodates the vertical displacement of a piping system. Spring cans help relatively small displacement (up to about 75mm).
Spring cans support function on the principle of Hooke’s Law, which states that the force required to compress a spring is directly proportional to the compression of the spring. Therefore, the reduction (i.e., the supporting effort) of the spring within the variable effort support changes in proportion to the forces exerted on it by the pipework as it rises/falls due to thermal expansion/contraction. This enables the spring support to safely accommodate and balance the vertical displacement, thus avoiding excessive pipework stresses.
We offer two-variable spring supports; ‘AV’ and ‘LV.’ please get in touch with us to see the full range of AV and LV pipe supports and their unique benefits over competitor products:
The AV and LV spring supports are available in four primary travel ranges; 35mm, 70mm, 140mm, and 210mm. These are designated AV35, LV35, AV70, LV70, AV140, LV140, AV210, LV210.
These travel ranges indicate the maximum working range of the springs. This full travel can be used provided that the necessary calculations are carried out to ensure that the connecting equipment and pipework can withstand the load changes that occur during pipe movement. Most national standards do limit the load variation to a maximum of 25%. It is therefore usual to select variable spring supports on this basis.
In keeping with generally accepted practice, we recommend that the actual pipe load is correctly supported when the pipe is in its normal working position. This ensures no abnormal or excessive forces are transferred to the pipework in its stressed working condition due to out-of-balance supporting effort.
The standard and optional design features of CPA variable supports are as follows:
STANDARD DESIGN FEATURES
- Recompression of the spring coil into the casing saves headroom and erection time.
- For each series, there is reserve travel at the upper and lower limits of the unit.
- All steel construction is rugged and compact.
- Grade 316 stainless steel is used for scale plates and nameplates.
- Load indicator visible.
- Spring Pressure plate serves as a centering device.
- Finish – hot dip galvanized – specialized coatings are also available.
- All ‘F’ type floor/base mounted units include load flange and internal load column guide.
- Travel stops – The Carpenter & Paterson design is supplied with stops to take the preset and hydrostatic test loads.
- No maintenance is required.
OPTIONAL DESIGN FEATURES
- Limit stops permanently installed to prevent the movement of the pipe beyond a predetermined distance or load within the travel range of the spring.
- Lifting lugs are available in large sizes to facilitate erection and installation.
- For extreme environmental conditions, we can manufacture our units in a range of austenitic stainless steel.
Contact Dannenbaum LLC for more information or a quote.