ブックタイトルPIPE HANGERS & SUPPORTS

概要

PIPE HANGERS & SUPPORTS

2. VARIABLE SPRING HANGER2.1 GeneralVariable Spring Hangers are used for supporting piping and equipment subject to vertical movement.They are used generally at points where stress due to transfer load does not have an adverse effect onthe overall stress of the piping system. Particularly in cases where the piping system has a largeflexibility, careful study is required because deflection is likely to occur even when there is only a smallstress variation due to transfer load.SANWA's Variable Spring Hangers use coil springs, so that the relationship between spring deflectionand supporting load is in linearity. Hence the following advantages are gained:1. Whereas Constant Spring Hangers have a constant supporting load and therefore require accurateload calculations, Variable Spring Hangers are applicable for a wide range of loads so that it is mucheasier to carry actual weights.2. By using a hanger with some allowance in travel range, the spring can be prevented from becomingrigid even when an unpredictable movement occurs in the piping system.Because of these advantages, Variable Spring Hangers are usually employed in the following two ways:1. Where vertical displacement in the piping system due to thermal expansion makes it impossible touse a Rigid Hanger and uneconomical to use a Constant Spring Hanger. In such cases, a VariableSpring Hanger is applied within the range of permitted transfer load for the purpose of supportingthe load.2. Where an appropriate compressive or tensile load is applied to the piping system to prevent itsvibration, while supporting the load. In other words, the Variable Spring Hanger doubles as avibration eliminator.Table 2-1Models Travel range FeatureVS1 0～30mm Suitable where displacement is small, as spring rate is large.VS2VSL20～60mm0～85mm Suitable where displacement is medium.VS4VSL40～120mm0～170mmCan be substituted for Constant Spring Hangers where pipe displacementis large but their use is uneconomical.Note: Commonly, Variable spring hanger can be used if the load variation dose not exceed 25 % per thefollowing formula;| Spring Rate × Design Travel |Load Variability 25 % ≧　ーーーーーーーーーーーーーーーーーーーーーーーー　× 100Design Load6