In CONSTANT Spring hanger the load remains constant THROUGHOUT its travel range. But In variable spring hanger the load VARIES with displacement.

Spring hangers are used when thermal displacements are upwards and piping system is lifted off from the support position. Variable spring hanger is preferable as this is less costly.

Constant springs are used:

1. When thermal displacement exceeds 50 MM
2. When variability exceeds 25%
3. Sometimes when piping is connected to strain sensitive equipment LIKE steam turbines, centrifugal compressors etc and it becomes very difficult to qualify nozzle loads by variable spring hangers, constant spring hangers can be used.

In Constant Spring hanger the load remains constant throughout its travel range. But In variable spring hanger the load varies with displacement.

Spring hangers are used when thermal displacements are upwards and piping system is lifted off from the support position. Variable spring hanger is preferable as this is less costly.

Constant springs are used: