Units in the ZF Series are functionally very similar to Equilibar’s “standard” multi-orifice units of the Low Flow Series, High Flow Series, and High-Temperature Series. What is different about the units in the ZF Series, is that they utilize a soft seat to effectuate zero flow pressure control. This means that engineers can use a ZF regulator from the Zero Flow Series to hold the pressure stable, even when the process is not generating any flow at all!
If minimizing the flow to zero is not an option for your application, the Ultra Low Flow series is an adequate alternative to this Zero Flow Series with similar superb control features for the smallest flows of process media.
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.
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 mln/min of gas or 100 mln/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.
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 mln/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.
|Hauptspezifikationen der Zero-Flow-Serie zusammengefasst
Eine vollständige Übersicht finden Sie in der Produktbroschüre, der Installations- und Wartungsanleitung und den Zeichnungen über die Registerkarten auf der linken Seite dieser Tabelle.
Kontaktieren Sie uns, wenn Sie nicht finden, wonach Sie suchen!
|Often used in||Processes without any flow of process media, such as reservoir core analysis, catalyst research – see Applications on the left|
|Maximum operating pressure*||ZF0|
|*For metal bodies;
Polymer bodies have a lower pressure rating, contact us to learn more
|Flow coefficient |
(min – max Cv)
|0 … 0,015||0 … 0,015|
|1 : ∞||1 : ∞|
|MAOT (in °C)||≤ 200°C with metal body + metal diaphragm + Viton O-rings
≤ 300°C with metal body + metal diaphragm + Kalrez O-rings
1/8″ NPT or BSPP
|Port thread options||ZF0 – HiP, Custom|
|ZF1 – HiP, Swagelok VCO/VCR®, Tube Stub, HPLC, Autoclave Speed-Bite W125, Custom
|Body & cap |
|Stainless Steel 316/316L|
|Body & cap |
|Hastelloy C276 Monel, Titanium, Zirconium
PTFE, PVDF, PEEK, PVC
(other materials upon request)
Stainless Steel SS316/316L
PGL (PTFE Glass Laminated)
|*Diaphragm thickness will be selected by our engineers based on your process parameters|
(other materials upon request)
|Viton® (FKM), Kalrez® (FFKM), PTFE, EPDM, Buna‐N|
|Body & cap material certificate 3.1.B
Diaphragm/O-ring material certificate (FDA and/or USP Class VI)
Surface finish certificate
Thread lubricant certificate (FDA)
Certificate of conformance 2.1
Assembly & Test certificate (leak and/or equilibrium flow testing)
Design certificate (MAWP according to ASME B31.3)
Notified-Body-declaration “simple apparatus” ATEX Directive 2014/34/EU available upon request
|Product options||Can be supplied including mounting brackets
|Spare part kits and/or Rebuild kits optionally available
See: Spare Parts and Maintenance
|Electronic & manual pilot control options available
See: How to pilot your back pressure regulator