Fusion and linear expansion
Expansion Loop
Bending parts should be used in installations where the expansion will be bidirectional and in runs exceeding 5 meters in length. Expansion loops cannot be removed for direction change, an expansion chamber must be designed. Shape of this expansion loop is given below.
Figure 9
Calculation of minimum width of expansion chamber: If the linear expansion cannot be compensated for by a change in direction, it may be necessary to install an expansion loop.
The pipe bend A min is calculated according to the following formula: Safety margin of 150mm is provided considering that elongation amount may increase under temperature fluctuation.
Length of freely moving part is calculated by the following formula:
Amin = 2 x ∆ ∫ x SD
A min : Minimum width of expansion loop SD: Safety margin (150mm) Ls: Length of freely moving part (mm) D: Pipe outer diameter ∆ ∫: Amount of elongation (mm) L: Pipe length (m) K: Specific constant of material (K=30)
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