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Fox Air and Gas Jet Venturi Ejectors

What are Fox Gas Jet Ejectors?

Fox Venturi Jet Ejectors (also called eductors, venturi jets, aspirators, jet mixers, jet pumps) use compressed gas (1 to 1500 psig) to exhaust, vent, compress, or mix another gas stream; or create moderate to deep vacuum (to below 1 psia.)

No Moving Parts - for Handling Corrosive, High-Temperature or Cryogenic, Explosive, Toxic, or Dust-Laden Gasses, Fumes, or Exhaust

Fox Venturi Jet Ejectors have no moving parts, no seals, no shafts, no packing, no maintenance. Their rugged construction and simplicity enables their reliable maintenance-free use with caustic, high-temperature, or explosive gasses - such as hydrocarbons. An ejector replaces the need for XP motors on fans or blowers.

Vacuum-Generation, Exhausting or Venting Vapors, Fumes, and Exhaust; Gas Sampling, and Compressing Gases

Common Applications

For detailed technical information about these specific applications, please visit the following pages:


Natural Gas, Methane, Vapor Recovery, Flare Gas Ejectors


Hydrogen/Natural Gas Ejectors in fuel cells


Gas sampling mini-eductors for analyzers, instrumentation

Where are the Fox venturi gas ejector capacity charts? How can I get a quick estimate of ejector capacity, motive gas consumption, size, and cost?

Only a small portion of the gas ejector inquiries we receive are for air-air at ambient temps, so published tables for air at 70° F are usually not useful for quick preliminary sizing of applications with different gasses at higher or lower gas temperatures. Our propietary computer models enable us to size the required ejector very quickly, for any gas at any temperature. The fastest way to get the right answer regarding what a Fox venturi ejector can do in your application is to complete our Application Data Sheet (choose either English or Metric units) and email to us at We aim for a same-day reply, although not always a quote, during normal working hours, EST in New Jersey.

What do we mean by 'off-the-shelf' gas ejectors?

Fox maintains a large inventory of assembled and unassembled 1/4" to 8" Fox venturi ejectors in carbon steel and stainless, manufactured in Dover, NJ, USA. This large inventory of unassembled ejector components enables Fox to quickly make modifications to ejector internals to suit application requirements - and still often ship in 1 to 1.5 weeks - or less. This includes remachining motive nozzle orifice to define required motive gas consumption, welding nozzle in place if required, and welding on flanges or other end connections or adaptors - all in our building.

This process of reworking existing ejector components enables Fox to supply, sometimes in days, what we call B+ 'proof of concept' prototypes for OEM applications, leading later to optimized, highly customized A+ production ejectors for integration into our customer's OEM equipment.

Gas Sampling for Analyzers and Instrumentation with Fox Mini-Eductors

Fox Air-Driven Mini-Eductors have been installed on thousands of analyzer systems for gas sampling since the 1960's. Please visit the Mini-Eductor section of our website for more information.

Schematics of Typical Applications

Venting, Evacuating, and Exhausting from Vessels, Tanks, and Chemical or Refining Processes

Fox Air and Gas Ejectors are frequently used as exhausters to vent gases from a tank or vessel

Pump Priming with Air Jet Ejectors

A Fox Air Ejector pulls a vacuum on a pump housing to evacuate
the suction line and draw water up into the pump

Purging or Evacuating Piplines or Tubing

Fox Ejectors are frequently used to purge or evacuate pipelines or tubing

Creating Deep Vacuum to 1 psia with a Two-Stage Air Ejector

Two-Stage Ejector System installed on the roof of the hypersonic wind tunnel at Princeton University

Venting Hydrocarbon Vapors to Flare Header in Oil and Gas Applications (Ref. EPA 40 CFR Quad O)

For information about Fox Gas Ejectors used in the oil and gas industries, please visit our Natural Gas Ejectors page.