SMC Networks IL220 Series, Operation Manual

Page: 5 / 13

1. Summary
Lock up valve is used for switching pneumatic circuit of air source and operation part when an
accident of air source and piping in pneumatic process control causes abnormal supplied air,
and air pressure lowers below setting pressure.
2. Specification
Signal pressure Max. 1MPa (Note 1)
Setting pressure range 0.14
～
0.7MPa (Note 1)
Line pressure Max. 0.7MPa
Effective orifice (Cv factor) 20mm
2
(1.1)
Ambient and fluid temperature
－
5
～
60
℃
Port size Rc 1/4
Differential 0.01 MPa
Mass 700g
(Note 1) Signal pressure and the set pressure must be different for more than 0.1 MPa.
Inadequate differential pressure may increase the bleed amount from the bleed hole
because of the wearing of internal part. This may effect on the performance.
3. Operating principles
When signal pressure entering the upper diaphragm chamber is larger than the force by
pressing adjusting spring, the diaphragm A moves upward, the exhaust valve is closed, signal
pressure enters the lower diaphragm camber, the diaphragm B is a affected, the valve is opened
against the spring, and the flow can go from IN1 to OUT.
When signal pressure is lower than the setting pressure, the diaphragm is pushed down and
the pressure of lower pressure diaphragm is exhausted from the exhaust valve. Therefore spring
A pushes up the piston, and the valve shuts the air circuit being open by the force of spring B.
This realizes the air passage from IN2 to OUT.
Pressure is adjusted by the screw.
-3-
Caution