Often times, control applications will demand precise pressure regulation of air or gases at high pressures. For this reason, Proportion-Air developed the QBS high pressure valve. This device uses two high pressure solenoid valves and a stainless steel sensor to control the pressure with an internal control board at an output accuracy of ±0.5%. This product is perfect for low flow (<1 SCFM) applications under static/deadheaded conditions. If higher flow rates are required, we can mount the QB2S on a volume booster and achieve just about any flow rate.

Choose among stainless steel, aluminum or nickel-plated brass bodies. The QBS is capable of controlling gaseous media anywhere from vacuum pressure to 500 PSI. Just as with all of our pressure and flow control products, whether your application requires -10.2 to 479.8 PSI, or 0 to 500 PSI, or whatever your exact need is, the output range is up to you. You name the range, and we’ll calibrate it!

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Accuracy ±


Repeatability ±

Max Flow (SCFM)

Max P2 (PSI)

QBS Downloads & Links
Documents Links Downloads
Installation Guide GX-Series File Request Form: Use this form to request a file other than a standard QBS .STEP file
Sales Brochure QB3H-Series Submit the form below to download standard QBS .STEP files
QBS Technical Specifications
Pressure Range Accuracy Repeatability Max Flow
Vacuum thru 500 PSI (34.7 Bar) ±0.5% F.S. ±0.05% F.S. 1.2 SCFM (34 LPM)
Port Size Durability Operating Temps Filtration
1/8″ NPT (BSPP Available) Immune to shock & vibration (up to 20 Gs) 32-158°F (0-70°C) 40 Micron



QB1S | Internal Sense

The QB1S is a complete closed-loop high pressure control device consisting of valves, manifold, housing and electronic controls. The QBS series utilizes an internal stainless steel sensor to accurately control pressures from full vacuum up to 500 PSI. The user supplies a command signal and the internal transducer constantly compares this command signal with actual downstream pressure. Then the control board will open the inlet valve to allow more pressure, open the exhaust valve to relieve pressure or close both and hold pressure when the two signals agree. The QB1S is designed to use in static and deadheaded applications requiring low flow.



QB2S | External Sense

The QB2S is similar to the QB1S but uses a double-loop control scheme. In addition to the internal pressure transducer, the QB2S receives an electrical signal from an external sensing device (pressure transducer, load cell, etc.). This primary feedback signal is compared against the command signal input. This comparison is then summed with the internal pressure transducer signal. The gain of the circuit is such that priority is given to the external feedback signal. A difference between the command signal and the feedback signal causes one of the solenoid valves to be activated. The QB2S can be paired with a high flow/high pressure volume booster to control high pressure to a process requiring high flow as well.

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