Benefits of using a Double Chamber 720 BXW valve

January 2016

The 720 BXW is an extremely powerful and versatile pressure reducing valve. It can be configured as either a single or double chambered valve.

Why choose a double chambered valve?

Let’s take a look at what a double chambered valve is, the applications for this product, where this configuration is beneficial, and the problems the valve solves.


Traditionally, the single chambered valve is seen as having a higher accuracy than a double chamber. Recent developments and advanced mechanisation has meant that the double chamber valve can now be as accurate.

Now, you can have the full and accurate control of a single chamber PRV, as well as the added benefit of upstream pressure acting above the diaphragm while the underside of the diaphragm is open to atmosphere. The result is an extremely responsive valve that can shut off with no pressure increase. With a Bermad 720 BXW Pressure Reducing Valve, you can have a large amount of flow running through the valve, have the flow shut off instantaneously, and have your downstream pressure remain completely unaffected.

Reduced risk.

In the event of a hydraulic lock-out, the valve is able to retain control. It makes the 720 BXW an ideal choice in any situation where there is a high risk of a system dead-heading.

Consider a scenario where a single chamber PRV has been used for pressure reduction – it’s good practice to install a pressure relief valve on the downstream side, to protect the pipeline from over pressurisation. In circumstances where demand is terminated quickly by the sudden closure of an isolation valve, a single chamber PRV can’t react fast enough to prevent an increase in pressure. That’s going to effectively dead-head your pipeline.

Since a double chamber valve only has atmospheric pressure below the diaphragm, any pressure change above the diaphragm will have an immediate effect on the valve position. This will ensure that the valve shuts quickly and smoothly. To see a functional comparison of single and double chambered valves in action, watch this live demonstration at the Bermad Interactive Training Facility.

Simple conversion.

There are still scenarios where a single chamber valve is required. Thanks to a unique and innovative design, the 720 BXW is easily converted from a single chamber valve to a double chamber PRV. The conversion process is simple, can be done in-situ, and doesn’t require any special tools or additional parts.

See our website for more information on the conversion process, the 720 Series Valve product page, and take a look at our video introduction and overview of the BXW Double Chambered Valve.

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