A Wheatstone bridge design is used to monitor the temperature dependent resistance gradient on the sensor windings which is linearly proportional to the instantaneous rate of flow

Both flow conduits are designed to ensure laminar flows and therefore the ratio of their flow rates is constant

Flow rates are unaffected by temperature and pressure variations within stated limitations

General Description Compact, self contained GFC mass flow controller is designed to indicate and control flow rates of gases

Principles of Operation Metered gases are divided into two laminar flow paths, one through the primary flow conduit, and the other through a capillary sensor tube

The GFC combines the characteristics, and accuracy of conventional mass flow devices into a unique compact design at low costs previously unattainable

The closed loop control circuit continuously monitors the mass flow output and maintains it at the set flow rate

The resultant temperature differential is proportional to the change in resistance of the sensor windings

The rugged design coupled with instrumentation grade accuracy provides versatile and economical means of flow control

The valve is normally closed as a safety feature to ensure that gas flow is shut off in case of a power outage

These controllers may be used as benchtop units or mounted by means of screws in the base

Transducer power supply ports are fuse and polarity protected.

Two precision temperature sensing windings on the sensor tube are heated, and when flow takes place, gas carries heat from the upstream to the downstream windings

Zero and span adjustments are accessible from the outside of transmitters