Zero Flow back pressure regulators

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

An important advantage of the Zero Flow pressure regulators compared to conventional (spring-loaded) pressure regulators, is that this back pressure regulator uses a  patented design based on a “floating O-ring hub” that – with the diaphragm – creates a complete and seamless closing, resulting in zero flow. Conventional regulators often struggle with a large pressure difference between the time of process media flow versus no-flow (also known as “cracking pressure”). You will not have that issue with an Equilibar Zero Flow unit.

Available sizes, Cv range & materials

The Zero Flow Series covers 2 different sizes, that are both capable of holding pressure up to 200 bar gauge over a Cv range of 0 to 0,015 and an infinite turndown ratio. 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.

ZF units can handle maximum flow rates up to 1500 ml_n/min of gas or 100 ml_n/min of liquid. Although higher flow rates would be possible, this could potentially lead to faster wear and tear on the controlling o-ring, for which reason we normally recommend other units for larger flow rates. You can contact the engineers of Pressure Control Solutions anytime to discuss your application details and for advice.

Diaphragms made out of stainless steel are standard. Customers often use Hastelloy diaphragms to withstand high corrosive brines. When combined with Kalrez o-rings, these Zero Flow pressure regulators can even be used up to 300 °C!

Find more material options in the SPECIFICATIONS table via the tabs on the left.

Electronic Pressure Control with the Zero Flow Series

For the Zero Flow series, an electronic pressure controller is commonly used to set the reference pressure. Since the maximum flow through this precision back pressure regulator is limited to roughly 1500 ml_n/min, using an electronic pressure regulator and a capillary or flow restrictor is highly recommended, in order to prevent a sudden decrease of reference pressure. The capillary will limit the speed of the decrease in the reference pressure, resulting in larger control stability.

Contact PCS for more information on how to get the most out of your  Equilibar Zero Flow regulator.

Equilibar® Zero Flow Series | Stable pressure regulation in absence of flow