About the Zero Flow series back pressure regulators

Cv: 0 to 0.015  |  Max. Temperature: 300°C  Max. Pressure: 206 barg (3000 PSI)


Engineers can use the ZF (Zero Flow) Series to hold the pressure stable, even when the process is not generating any flow. An o-ring seals the outlet orifice. When operating at its lowest capacity the Cv value comes close to the leak through a tiny o-ring. In Cv values, this equals 1·E-10. The largest flow rate has a limit of roughly 1000 sccm of gas or 1 sccm liquid.

The properties of Zero Flow regulators are very beneficial for applications where flow consumption is very low, such as in core analysis or catalytic research where you low flow rates of hydrogen are used.

All units in the Zero Flow series are capable of holding pressure up to 200 bar gauge. Diaphragms made out of stainless steel or Hastelloy are standard. Customers often use Hastelloy diaphragms to withstand high corrosive brines. ZF units can be used up to 300°C when combined with Kalrez o-rings.

Customers often use the zero flow series in combination with a manual or electronic pressure controller to set the reference pressure.

Since the maximum flow through this precision back pressure regulator is limited to roughly 1000 sccm, we design the solutions to prevent a sudden decrease of reference pressure. Therefore we often use a combination of an electronic pressure regulator and a capillary. The capillary limits the speed of the decrease in the reference pressure. Contact us for more information on how to get the most out of your Equilibar® ZF series.

You can view an extensive explanation of the Zero-Flow series in this video:

Ultra Low Flow Series or Zero Flow Series?

When it is impossible to prevent large amounts of media from flowing through the back pressure regulator, you will want to use the Ultra Low Flow series. These units have a performance overlap with the Zero Flow series, but they don’t contain the small o-ring that can be damaged while overflowing the unit. If necessary, you can convert the Zero Flow series into the Ultra Low Flow series yourself with only one additional spare part. It takes only a few minutes to rebuild the unit and it doesn’t require any tuning.

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