MULTYRAMA GUIDA INGLESE 21-10-2009 12:57 Pagina 15
9.
INSTALLATION TECHNIQUE
COMPENSATION USING EXPANSION ARMS
By using such a technique installation is realized by conferring to the lay out a geometry which consents absorption of expansion. For this aim are realized, in correspondence with directional changes (elbows, T’s), expansions arms whereby the pipe has the possibility to expand during the presence of thermal stress.
GRAPHICAL EXAMPLES
Shown below are a few examples of correct installation for external Multyrama systems using diverse techniques adopted to take into account thermal expansion of material.
Calculation of these expansion arms is carried out by way of the following L
formula: LS = F • √ D • ΔL
EXAMPLE
ΔL
ΔL
L
wherein:
F =
material constant (for multi layers = 30)
D =
external diameter of pipe (mm)
ΔL =
variation of lenght of pipe (mm)
FP
FP LS
lenght of expnasion arm (mm)
LS
LS =
FP D =
20 mm
L =
8m
ΔT =
50°C
from the preceding example is obtained: ΔL =
10.4 mm of which
LS =
30 √ 20•10.4 = 433 mm
FP
Example of dilating arm
ΔL
LS
LS
L
LP FP
FP
FP
30
Colori compositi
LP
31
L
ΔL