Regulators

Buying guide

The gas settles most of the decision before anything else, because a regulator's wetted materials have to match what passes through it. An oxygen regulator must be clean for oxygen service and cannot carry hydrocarbon traces; a regulator for corrosive gases such as chlorine or hydrogen chloride needs a body and diaphragm that resist attack, which is why stainless steel construction appears so often in this class. The cylinder connection matters just as much: fittings are standardised by gas and by region, so a regulator built for one CGA or DIN outlet will not thread onto another without an adapter you should avoid using on hazardous gas. Confirm the inlet and outlet pressure ranges too, since a two-stage unit holds delivery pressure far more steadily as the cylinder empties than a single-stage one does, which is what fine analytical work usually needs.

On a used unit, the diaphragm and seat are what wear, and they are what you cannot see from a photograph. Ask whether the regulator was last used on a clean gas or a reactive one, because residue from a corrosive service can leave seats pitted and springs fatigued. A creeping outlet pressure, where the delivery gauge climbs with no flow drawn, points to a failing seat and is the single most common fault on second-hand regulators. Gauges themselves drift and can be replaced; the internal mechanism cannot be judged the same way. For any instrument-grade application, plan to verify or recalibrate the delivery setting against a reference before trusting it.

Price tracks that complexity closely. The lower end of the cost range covers basic single-stage cylinder regulators and bare gauges, well within a modest budget, while the upper figures belong to specialty and high-purity assemblies in stainless steel. Across the catalogue the average sits nearer the lower end, and refurbished regulators listed for sale remain more affordable than new equivalents of the same type. Linde, Various, Liquid Air, VWR, Matheson account for much of what is listed, which helps when you want to compare like for like or match a replacement to an existing manifold. Where warranty matters on a particular unit, it is arranged in consultation for that specific listing.

Types of Regulators

Which regulator types are listed?

Among the listings that specify a type, the common forms are gas pressure regulator, laboratory gas regulator, pressure regulator, specialty gas regulator, stainless steel regulator, gas regulator. A gas pressure regulator is the general case: it takes cylinder pressure at the inlet and holds a lower, steady pressure at the outlet, and most laboratory bench use starts here. A specialty gas regulator is built for a defined gas or purity grade, with cleaned internals and materials chosen for that service, and is what a lab reaches for with calibration mixtures, high-purity carrier gas, or reactive gases. Stainless steel regulators form a distinct group because the wetted path resists corrosion and outgasses little, which is why they dominate high-purity and corrosive-gas work. The split that separates them in practice is single-stage against two-stage: a single stage is simpler and cheaper, a second stage buys constant delivery pressure as the cylinder drains, which analytical instruments depend on.

Much of this equipment feeds life-sciences and biotechnology work through the gases it controls. A carrier-gas regulator supplies the helium or hydrogen line behind gas chromatography, and a stable two-stage delivery is part of why GC retention times stay reproducible. Specialty regulators handle the CO2 supply to a cell culture incubator, holding the fixed percentage a culture needs, and the gas mixtures used in anaerobic microbiology and in cell imaging chambers. High-purity stainless steel regulators also sit on the sample and reagent gas lines in proteomics and genomics instrumentation, where a trace of hydrocarbon or moisture would reach the detector. In each case the regulator is doing one job, delivering a clean gas at a controlled pressure, for a process that cannot tolerate drift.

The brands behind the regulator listings

The names that recur most are Linde, Various, Liquid Air, VWR, Matheson. A concentration around established makers helps a buyer in a practical way: seats, diaphragms and gauges for a widely used line are easier to source as spares, and a second unit of the same model is straightforward to compare against one already on the bench. The presence of a "Various" grouping reflects the mixed second-hand supply, where individual regulators come through without a single dominant maker, and these often sit at the lower price points. Matching a replacement to an existing manifold is simpler when the inlet fitting and brand already appear in the catalogue.

What a used regulator costs here

Condition is heavily weighted toward used stock, with 92 percent of the listings used. Prices span from EUR 6 to EUR 9.175, and that range maps onto the type split above. The low figures cover single-stage cylinder regulators, individual gauges and spares; the high figures belong to stainless steel specialty assemblies for high-purity or corrosive service. The average lands toward the lower end of that spread. Parts for a listed regulator can be sourced via Questpair, and where a warranty is relevant it is settled in consultation for the specific listing.