Appendices
January 2023
•
Rev. 0
• Standard Devices User Manual
45
Appendix C: Application Setup
MCV Controller Operating Notes
Alicat’s MCV mass flow controller is equipped with an
integrated Swagelok® positive shutoff valve. This valve is
normally closed, but can be opened by supplying 60–120
PSIG of air pressure. The shut-off valve closes again when
this pressure is reduced below 60 PSIG.
A common method for actuating the shutoff valve incorporates
a three-way solenoid valve (shown to the right). Pressure is
applied to one side of the solenoid valve while the other side
of the solenoid is left open to atmosphere. When the solenoid
is energized, pressure is delivered to the shutoff valve, causing
it to open. When the solenoid is returned to a relaxed state,
the gas vents to atmosphere, allowing the shut-off valve to
close.
Pressure Controller Applications
Forward (Downstream) Pressure Control
When the valve is located on the upstream side (direct control), the sensor controls pressure downstream. This configuration
follows our standard pressure control algorithm. The valve opens to increase pressure, and closes to decrease pressure.
+0.0
+0.0
+13.49 +22.73
Mass Flow
CCM
SCCM
MENU
PSIA
¤
C
SETPT
+0.0
SCCM
A ir
Three-way
solenoid valve
Vent
60―120
PSIG
MCV
Mass flow
controller
Pressure opens
the shutoff valve
Typical MCV configuration.
MCV-1SLPM-D mass flow controller.
Gas Supply Pressure Regulator
Pressure Controller
Process Flow Exit Port
Upstream Valve
