Technical Guide
DAN-LIQ-TG-44-rev0813
November 2013
46
OPEN - CONTROL POSITION - The normally closed solenoid is closed. The normally open solenoid is closed.
The power cylinder medium (P3) cannot flow to or from the power cylinder. The piston is pneumatically
locked in position until the electronic presets command the valve to open or close as required to maintain the
desired flow rate.
Figure 7-6
39
Figure 7-7
OPEN POSITION - NO CONTROL - The normally closed solenoid is open. The normally open
solenoid is closed, blocking the exhaust port, and pressure (P3) is applied to the power cylinder.
The pressure on the bottom of the power cylinder piston (P3) is greater than the pressure applied
by the spring force. Therefore, causing the valve to go full open (No Control). The opening speed
needle valve controls how fast the valve opens or responds to a flow rate change.
= Inlet Pressure
= Outlet Pressure
= Power Cylinder Supply Pressure
= Power Cylinder Spring Force
P2
P1
P3
= Inlet Pressure
= Outlet Pressure
= Power Cylinder Supply Pressure
= Power Cylinder Spring Force
P2
P1
P3
Flow
Flow
Solenoid (N.C.) Solenoid (N.O.)
Opening
Speed
Closing
Speed
Power
Cylinder
Solenoid (N.C.) Solenoid (N.O.)
Opening
Speed
Closing
Speed
Exhaust
Supply
Pressure
(30 PSI Max)
Exhaust
Supply
Pressure
(30 PSI Max)
Power
Cylinder
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