Tracer Gas Handling Systems

Tracer Gases in Production Processes

Tracer Gases are repetitively used in leak testing of components in manufacturing processes. Typical tracer gases used in leak testing are helium, hydrogen, and various refrigerants, such as R22. After each component leak test, recovery of tracer gases is functionally and economically required. Helium gas recovery is accomplished in VTI’s Tracer Gas Recovery (TGR) System. Recovery of refrigerant tracer gases is accomplished in VTI’s Refrigerant Vapor Recovery (RVR) System.

The TGR and RVR links are to more detailed information about each of these VTI products. If you require a system for recovery of other tracer gases, other than helium, hydrogen, or refrigerants, please contact our VTI Leak Testing Experts for a solution. When refrigerants are used as a tracer gas, tracer gas handling systems are required. VTI offers both Refrigerant Tracer Mixing Systems and Tracer Gas Boost Systems.

Refrigerant Tracer Gas Mixing and Boost Systems

VTI designs and manufactures complete Refrigerant Tracer Gas Mixing and Boost Systems. A mixing system is shown at left and a boost system at right. When using refrigerant as a leak testing tracer gas in an HVAC production facility, the refrigerant/air mix must be controlled to an exact R22/Air ratio for the process. The VTI Tracer Gas Mixing System maintains the R22/Air ratio within +/- 2% of the target ratio. In addition, when the use rate of refrigerant tracer gas is high, a tracer gas boost system is required.

Boost Systems are custom-designed for your process. The example in the photograph requires 100 psig of low pressure refrigerant tracer gas mix and boosts the pressure of the mix to greater than 200 psig for use in large chamber leak testing systems.

Low Cost Tracer Gas Mixing Station

Your total cost of tracer gas (i.e. helium) usage can be minimized by adjusting the tracer gas mix for different lots and sizes of parts to be leak tested, where the acceptance criterion may vary. This Mixing Station is capable of supplying the same mix of tracer gas to multiple leak test stations. The benefit of this inexpensive mixing station is ease and convenience in adjusting the percentage of tracer gas used to achieve adequate sensitivity in leak testing various parts to be tested.


PLC-controlled batch mixing function
User adjustable gas mix percentage from 5% t0 100% in 5% increments
Stainless steel valve manifold
Appropriately-sized gas mixing cylinder rated with internal diffuser
Nupro 4BK valves with 1C normally closed air operator and bellows sealed actuator
100/250/500/1000 psi range sensors available
Top mounted status indicator light
Isolation valve, filter, dual gauge, and inlet check valve for Tracer Gas and Mix Gas
Pressure booster option available
Custom versions available


-110VAC Input Power
-Regulated and Filtered Air at 80 to 100 psig for Pneumatic Control
-Regulated and Filtered Tracer Gas Supply at up to 100 psig

This is similar to the Outside-In test except that the hood or chamber into which the evacuated part is positioned has been removed. The significant change is that an operator now probes around the part with a sprayer wand allowing trace gas to flow, selectively, around potential leak sites such as joints and fabrication seams.

As the wand passes a leak, small amounts of trace gas that enter the part are detected by the leak detector. In this way, the location of the leak may be pinpointed, with accuracy, if care is taken. This technique can be more sensitive than Sniffing but the operator must be wary of tracer gas drift which can be confusing. It would take much longer to test a complete part in this way than with an automated system. This technique is usually reserved for testing components which have failed a general Outside-In test. VTI Outside-In systems have a spray wand to allow quick checks on key joints to be made on-line by an intervening operator.