2-11
2-6. SVP for springless double-acting actuators (Reversing relay)
When an SVP is installed on a valve with a springless (double-acting) actuator, air pressure is
needed on both the bottom and top of the actuator diaphragm to provide valve opening and
closing proportional to a control signal. A reversing relay is used for this purpose.
Supply air connection
(not shown)
Reversing relay
Output air connection 2
(not shown)
Output air connection 1
Relay air connection
Output air pressure gauge
Fig. 2-9.
Note) Make sure that the air piping connections and air pressure ranges as inscribed on the
bottom of the reversing relay match your SVP.
The reversing relay has two Output air connections:
Output air connection 1 (OUT1) which passes through the SVP’s output air pressure
Output air connection 2 (OUT2) with the balance of the supply pressure (minus SVP
output air)