High Resolution Back Pressure Valve

High Resolution Back Pressure Valve
This video shows a laboratory demonstration of a back pressure regulator that has high resolution and can accurately control pressure to within fractions of an inch of water column. https://www.equilibar.com/products/
Equilibar Vice President David Reed uses an Equilibar® GSD3 series back pressure regulator to control the output pressure of a pump to between 14 and 15 inches of water column. This is about ½ of a psi or around 35 milliBar. The Equilibar back pressure valve uses a thin supple membrane (diaphragm) as the only moving part and is therefore able to operate with very low hysteresis. The Equilibar GSD3 valve is pilot operated. In the video an Equilibar QPV1 electronic pressure regulator is used to provide an air pilot signal to the dome of the Equilibar back pressure regulator. The command signal for the electronic regulator is from a height sensing proximity sensor which measured the height of David’s hand. Since the Equilibar is a precise one to one relationship between the pilot and the controlled pressure, the demonstration should show the height of the hand, the pilot pressure (in inches of water column on the pressure gauge), and the actual height of the water column all matching up. While there are slight differences the demonstration makes it clear that the pressure could easily be modulated within an inch of water column.
The purpose of the video is to demonstrate that the Equilibar pressure regulator design can be controlled accurately to within a fraction of an inch of water column. This can be very useful in applications controlling the differential pressure across a membrane. Examples of this include fuel cell membrane development or testing and transmembrane pressure control (TMP) in tangential flow filtration (TFF) or in ultrafiltration applications. We also believe that high pressure water hydrolysis applications could make use of two Equilibar pressure regulators to control the pressures of hydrogen and oxygen gas very closely while at an extremely high common mode pressure.
This video was shot using a demo that was built for use at the InterPhex BioPharma trade show in New York City in April 2018. The pilot pressure signal in the video is from an Equilibar QPV series electronic pressure regulator. It has a full scale calibration of 0 to 10 VDC = 0 to 30 inches of water. We purchased the proximity sensor (ultrasonic) from automationdirect.com