Equilibar® back pressure regulators explained

The Equilibar back pressure regulator is an instrument that maintains the upstream pressure at its own inlet. It uses patented technology to enable high precision and stability in controlling the pressure in your chemical process. It is particularly suitable for low flow, extreme temperature, mixed phase fluids, corrosive media and sanitary process conditions. Performance of the Equilibar back pressure regulator is unparalleled in the industry!

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Unique pressure control features

These unique dome-loaded back pressure regulators work by a remarkable force balance on a flexible diaphragm between three different pressures. The lower pressure at the outlet attempts to hold the diaphragm in a leak-tight seal with the orifice. A slight excess between the fluid inlet pressure and the reference pressure rapidly overwhelms these seating forces and lifts the diaphragm off the orifices. The result is an incredibly fast response, maintaining the inlet pressure in a tight equilibrium with the pressure set at the reference.

When the pressure at the inlet exceeds the pressure set at the reference, the valve will open to relieve pressure. Equilibar back pressure regulators control the inlet pressure (upstream) by opening up just enough to hold back the wanted inlet pressure (upstream).

Applicable for demanding and even unknown process conditions

In practice, the conditions under which a future (experimental) process will operate are often unknown when preparing to build such application. Equilibar ® back pressure regulators can be operated with large variation in design specifications and therefore enable very broad process parameters.

In this context, it is useful to take a closer look at one of the challenges of stable back pressure control: The influence of the upstream pressure on the sizing of the regulator. Applications with a constant inlet pressure upstream of the valve often use traditional valves. As soon as the downstream pressure is less than 45% of the inlet pressure, the (traditional plug and seat) valve becomes overcritical and has no impact anymore. For our back pressure regulators, this is different: In back pressure mode, the valve needs to vary the inlet pressure. A large Cv range is often needed in such cases. And in more specific cases, also flow rate and media properties are variables. Traditional valves can’t always offer the desired Cv rangeability with so many variables (read more below about the comparison of our back pressure regulators against more traditional valves).

The Equilibar back pressure regulator is a valve that is developed for this purpose: It offers a 1:100.000 Cv rangeability due to the multiple orifice design and therefore enables single valve solutions covering the whole range. The Equilibar back pressure regulator can also handle variable flow rate, media properties like changing density and viscosity over a wide range of temperatures.

Comparison: Equilibar and traditional back pressure regulators

A traditional back pressure regulator uses springs to set the upstream pressure. The change in the spring force as it is compressed is a major source of error or overpressure in a traditional design. The Equilibar back pressure regulators use a thin flexible diaphragm as the only moving part. Therefore it allows the unit to have frictionless operation without cracking pressure or hysteresis. The unique Equilibar multi-orifice design gives an ultra-wide flow range, typically 100X wider than a traditional back pressure regulator.

Applications using back pressure regulators

Equilibar back pressure regulators outperform other designs in applications with e.g. low flow rates, mixed phase fluids, corrosive media, or extreme temperatures. The Equilibar back pressure regulator provides an unmatched stability through flow rate ranges as wide as 1000:1 and 100,000:1.

We offer you different product categories for different fields of application: The Research series is designed for use in research settings and comes in different variations for zero, (ultra) low, and high flow as well as high temperatures. BR series is specifically suitable for use in super-critical extraction. The GS series is particular for pilot plants; BD series with its different line sizes can be used for industrial applications and FD series is specific for sanitary applications. The SD series serves to accommodate the rapidly expanding requirements of BioPharma industry with a single use design instrument. Last in this list – the EVR series focuses on vacuum applications.

On our Applications page, we list a number of customer applications  using our back pressure regulators and electronic pressure controllers.

Pilot control for your back pressure regulator

The precision of the Equilibar back pressure regulator is primarily limited by the accuracy of the reference set-point on the dome. You can apply the reference set-point pressure by a manual forward pressure reducing regulator or with an electronic pressure controller (single valve or dual valve). Electronic regulators provide the most flexibility and the most accurate result.

In sophisticated pilot plant and R&D processes where you require maximum performance, stability, accuracy, and reproducibility, we recommend closed loop control between the actual process pressure and the reference pressure. Contact us for more information on closed-loop control.

Below you can find more in-depth information about the various types of back pressure regulators that we offer. Feel free to contact us for a quotation or trial delivery and convince yourself. We will help you configure the optimal product solution for your process requirements and pressure challenge!

Go to our Product Configurator to explore all product variables!