3-1
PC100 Series
Installation and Operation Manual
X-PR-PC100-Series-PC-eng
Part Number: 541B207AAG
May, 2017
Section 3 Operation
3-1 General
After the device has been properly installed in the process, it is ready for
operation. When initiating flow, slowly open any upstream shutoff valve to
avoid a flow surge. A bypass is helpful in bringing the flow on smoothly.
Avoid starting a pump to supply the device without the use of a valve
upstream of the device.
3-2 Theory of Operation for Pressure Control
The PC100 Series measures pressure via its internal pressure transducer.
When the system pressure changes, the PC100 Series will manipulate the
flow to achieve and maintain pressure setpoint. Unlike traditional pressure
control devices, the PC125 Pressure Controller leverages the mass flow
measurement capability and sensor accuracy of the GF1xx Thermal Mass
Flow series. For the downstream PC125 device, gas flow first travels
through the control valve into the bypass. The gas flow entering the bypass
is separated into two paths; one straight through the bypass and the other
through the thermal sensor. Both gas flow paths are reunited at the outlet
of the bypass in the same relative location to the pressure transducer port
location. The PC125 provides accurate pressure control while providing the
customer with accurate flow measurement.
