Back Pressure Regulator for Low Flow | Pressure Control

Back Pressure Regulator for Low Flow

Very Low Flow and Zero Flow Applications

Conventional back pressure regulators often have trouble maintaining target pressure at extremely low flow rates. Equilibar has designed some back pressure regulator models specifically for ultra low flow and zero flow applications.

For pressure control applications requiring flow rates below about 10 ml/minute, Equilibar offers the UL (Ultra Low) series and the ZF (Zero Flow) Series.

The Equilibar® ZF takes performance down below the nano liters/minute range. This makes the ZF Series back pressure regulator a true microfluidics pressure regulator. The Cv ranges from 0 to 0.15 and controls pressure up to 3000psig/200bar(g) It is available in HPLC inlet/outlet port and 1/8″ NPT inlet/outlet port. For custom port sizes, please contact an Equilibar application engineer.

The Ultra Low Flow Series (UL) performs similarly to the standard Research Series back pressure regulators, but can operate at lower flow rates. The Cv ranges from 1E-9 to 0.05 and can control pressures up to 10,000 psig / 680 bar(g). There is also a high temperature model for extreme applications up to 450C. Inlet and outlet port sizes are 1/6″ HPLC, 1/8″ NPT and 1/4″ ‘NPT.

Equilibar Research Series Back Pressure Regulators are addressing many critical laboratory and microfluidics needs by providing precise control at the lowest flow rates in the industry. The Equilibar back pressure regulator’s unique design easily provides flow turndown ratios of 10,000:1 and up to 100,000:1 in many cases to meet a multitude of research conditions.


ultra low flow back pressure regulator

Zero-Flow Capable ZF Series BPR
The EB1ZF1 hold stable inlet pressure from true zero flow up through 1000 ml/min. See our Research Series BPR brochure for details.


Ultra wide flow range back pressure regulator with high turn down ratio and low flow performance


Gas Analyzer Application

The Research Series back pressure regulators are ideally suited for addressing critical low flow problems commonly found in gas analyzers. The carrier gases used in gas analyzers typically have a controlled flow rate going in. Because the carrier gas flow is often very low, the low flow model back pressure regulators from Equilibar are ideal for this situation. The petrochemical research industry, in particular, is finding many new applications for the products using SS316 bodies and PTFE diaphragms.

Schematic of Gas Analyzer

schematic of gas analyzer

High Pressure / Low Flow

An interesting feature of the Equilibar back pressure regulator is that the low flow performance actually improves with increasing set-point pressures. This is due to the increased seating forces of the diaphragm against the outlet orifices.

Contact Equilibar to for additional assistance with your very low flow back pressure control application.

 back pressure regulator details for low flow applications

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