Mass Flow Control Using a Back Pressure Regulator


Equilibar precision back pressure regulators find a new use as an open loop flow control valve. Most flow control applications use a variable orifice flow modulating valve, a mass flow transducer, and a PID loop to provide closed loop flow control. Many flow control applications can't use a traditional flow control valve with flow transducer and PID control loop. Temperatures may be too high for the flow transducer or the chemistries too aggressive. The PID loop may be too slow to respond to transients. In some cases the expense of the control valve, flow transmitter, and PID may be more than the degree of accuracy required by the application. In all of these cases an Equilibar back pressure regulator can provide a simple flow control solution. By setting the P2 and thus maintaining the differential pressure across an orifice, accurate control of flow is automatically obtained through the natural function of a back pressure regulator. Restrictions and pressure variations in the downstream system are automatically compensated for through the natural mechanical action of the back pressure regulator. For applications which require a wide range of flow rates, a simple fixed orifice may be replaced by a variable orifice valve. The Equilibar back pressure regulator controls the differential pressure across the variable orifice valve allowing high turn down ratios of up to 100:1 Equilibar offers an instructional video presentation at http://equilibar.com/back-pressure-regulator/flow-control-back-pressure-regulator.asp

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