Frequently Asked Questions | Pressure Control | Equilibar

Frequently Asked Questions

What makes the Equilibar technology unique?

The Equilibar® back pressure regulator uses a fully frictionless design that is dramatically more precise than ordinary back pressure regulators – especially in the low and medium pressure ranges.

This unique approach also provides much greater support for ultra low pressure applications and very low flow applications.

See Features and Benefits for more information.

How do I provide my SetPoint to this regulator?

The Equilibar® achieves it precision by providing a fluid set-point pressure to the top of the diaphragm.

For manual applications, we can provide an optional Air Spring SetPoint Kit (as shown above). For automatic applications, we can provide an optional Electro-Pneumatic Regulator Kit. Finally, for very low pressure applications, we offer the LPR2 Ultra Low Pressure Regulator for the set-point kit.

How is this different from other dome-loaded back pressure regulators?

The Equilibar® is a type of dome-pressure regulator, but uses a innovative seat design giving it much higher precision and stability from 0 -100% of its flow range. Traditional back pressure regulator seat designs are typically optimized to be stable in limited flow ranges. Learn more about How it Works.

How low pressure can it control?

The Equilibar offers unmatched performance in very low pressure ranges, with excellent control down to about 1″ water column (0.02 psi). Depending of flow and body size, it can easily achieve precision better than 0.25″ water column (0.01 psi). Learn more about Low Pressure Back Pressure Regulators or our full line of Low Pressure Solutions.

What other features make the Equilibar® back pressure regulator unique?

  • Springless; a special flexible diaphragm is the only moving part
  • Compatible with problematic shear sensitive applications
  • Simple, sanitary design compatible with pharmaceutical or food applications
  • Extremely fast response
  • Dampens system pulsations
  • Reference pressure can be a second process fluid (fluid pressure balancing)

How can I use the Equlibar® back pressure regulator to automate my process?

The Equilibar® excels at computer automation applications. By connecting an electro-pneumatic transducer to the reference port, the Equilibar® allows your process computer to vary process pressure with precision to 0.01 psi! This could be used for everything from simple flowrate control to controlling reactor conditions in a research environment.

Features and Benefits


Ultra Low Pressure

The Equilibar® has the lowest pressure control range and highest sensitivity it its class. Set-point control to 0.02 psi and below, with sensitivities to 0.01 psi. Note: ultra high precision typically applies to gas applications or very low flowrate liquid applications due to the inherent fitting losses in all liquid controls.

Ultra Low Flow Rates

Typical spring and plunger designs have a difficult time seating properly at extremely low flowrates. For example, an imperfect seal between plunger and seat could result in “negative overpressure” at extremely low flow rates (especially in gas control). The Equilibar® can be configured with special low flow trim (“-LF”) to perform in the range of 1 ml/min gas flow.

Easy Process Automation

The Equilibar® Pressure Regulator makes computerized automation of fluid process pressure a breeze. The 1:1 relationship between the process pressure and that of the reference air signal pressure is easily established by any electronic pressure regulator (electro-pneumatic transducer . . E/P, I/P), w). There is never any need for calibration to keep the two pressures together (as with a pilot-operated regulator); the pressure balance is maintained naturally by the flexible diaphragm.

Shear Sensitive Fluid Compatibility

The Equilibar® can tackle tough shear sensitive fluids and dispersions where traditional fluid controls fail. The flexible diaphragm throttles fluid pressure in a less abrupt manner than traditional valve seats. The self adjusting nature of the membrane valve seat allows the valve to easily ingest and pass particulate matter. (see shear sensitive application information)

Suitable for Pharmaceutical, Food, and Bio-Engineering Industries

The Equilibar® Pressure Regulator has an inherently sanitary design that is suitable for food, pharmaceutical, and bio-engineering industries. The main valve body can be disassembled using a sanitary clamp for quick and easy inspection and cleaning. Valve seats are inherently crevice-free and can be readily flushed with Clean-In-Place solution, steam, or water. Sanitary end fittings available.

1:1 Pressure Equilibrium

The pressure relationship between the reference and process ports in not simply proportional, as with existing pilot-actuated control devices. The Equilibar® Pressure Regulator attempts to maintain this relationship in 1:1 equilibrium naturally – with no calibration needed or possible. (Various configurations are available that add a slight opening or closing bias to this equilibrium)

Ultra-Fast Action

Because the only moving part in the Equilibar® Pressure Regulator is an flexible diaphragm, there is no friction, and virtually no inertia to slow reaction times. Consequently, the action of this device is extremely fast, nimble, and responsive.

Pulsation Dampening

By using this device in the flow-through configuration, the Equilibar helps to dissipate pressure pulsations by directing much of the excess pressure wave into the exhaust port. This is particularly effective when the device is used on the outlet of a diaphragm pump, as illustrated in the Pump Pressure Control application.

Drip-Tight Performance

Conventional relief valves require significant seat loading forces to eliminate dripping. Even devices with compliant seats can drip as they approach their cracking pressure. The Equilibar® Pressure Regulator has the unique ability to remain drip-free to within a fraction of a psi of set-point.

Eliminates Overpressure

Traditional relief valves open up gradually only as overpressure compresses the spring to its most retracted position. . The Equilibar® Pressure Regulator eliminates this design complication by providing full open flow at less than 1 psi overpressure.

1/2" Equilibar Precision Pressure RegulatorPerformance comparision for Equilibar back pressure regulator

The precision of Equilibar regulators is unparalleled.
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The start of a new year always brings an uptick in inquiries at Equilibar.  We invite engineers and researchers  to check out our product brochures for in-depth information about our innovative fluid control valves and back pressure regulators.  See our product literature page or read on for a round-up of our most popular offerings. Research Read More

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