Samson 3256, Mounting And Operating Instructions, Page: 28 / 84

5-2 EB 8065 EN
Installation
Vent plugs
Vent plugs are screwed into the exhaust air
ports of pneumatic and electropneumatic de-
vices. They ensure that any exhaust air that
forms can be vented to the atmosphere (to
avoid excess pressure in the device). Further-
more, the vent plugs allow air intake to pre-
vent a vacuum from forming in the device.
Î
Locate the vent plug on the opposite side
to the work position of operating person-
nel.
Table 5-1: Inlet and outlet lengths
Q
b x DN
a x DN
Q Flow rate
a Inlet length
b Outlet length
State of process medium
Valve conditions Inlet length a Outlet length b
Inlet Outlet
Gas
Ma ≤ 0.3 2 4
0.3 ≤ Ma ≤ 0.7 2 10
Vapor
Ma ≤ 0.3 1) 2 4
0.3 ≤ Ma ≤ 0.7 1) 2 10
Saturated steam (percentage of con-
densate > 5 %)
2 20
Liquid
Free of cavitation/w < 10 m/s 2 4
Cavitation producing
noise/w ≤ 3 m/s
2 4
Cavitation producing
noise/3 < w < 5 m/s
2 10
Critical cavitation/w ≤ 3 m/s 2 10
Critical cavitation/3 < w < 5 m/s 2 20
Liquid
Liquid, with
flashing
– 2 20
Multi-phase – 10 20
1)
No saturated steam