Festo MPAL-VI - Preventing Back Pressure

3 Mounting and installation
52 Festo – MPAL-VI-EN – 2017-07a – English
3.4.3 Preventing back pressure
When exhausting large-volume actuators or if the exhaust performance is too small, back pressure can
build up in the valve terminal's exhaust ducts.
This back pressure can lead to pneumatic actuation of other valves, especially with unswitched 3/2-way
valves that are normally closed.
 Optimise pressurisation and exhaust performance of the valve terminal, e.g. with the following
measures:
– Bigger tubing diameters
– Additional supplies through supply modules
– Exhausting via supply modules with silencer or exhaust plate
– Use pressure zones to separate exhaust ducts è Chap. 2.4.4.
 Install check valves in common exhaust lines.
1
2
35
6
6
2
2
4
1 First valve terminal
2 Common exhaust lines (3/5)
3 Central control exhaust line (82/84)
4 Central exhaust line (3/5)
5 Second valve terminal
6 Common exhaust lines (82/84)
Fig. 3.3 Preventing back pressure in common exhaust lines