Internally Purged Valves, Injectors, and Selectors

internally purged injectors
  • Protect your work – block any possible diffusion from the atmosphere
  • Protect your workplace – safely vent any fugitive emissions from the valve

The measurement of low ppb atmospheric gas concentrations may necessitate the purging of any leakage across the sealing surfaces and/or any diffusion through the sealing material. Designs which employ a "purging groove" on the rotor are successful at capturing surface leaks, but are ineffective at purging the air which diffuses through the polymeric rotor.

leak rate graph

Valco offers two methods for capturing and purging both types of leakage: a valve with the purge feature built in, or a purge housing around a standard valve.

Both methods are available for most Valco injectors and selectors with 1/16" or 1/8" fittings; however, space-saving internally purged versions are not available for some smaller bore 1/16" models. Some example product numbers are listed below.

Internally purged sampling and switching valves, 1/16" fittings, 0.75 mm bore
Actuator 4 port 6 port 8 port 10 port
Air A2C4UWEPI A2C6UWEPI A2C8UWEPI A2C10UWEPI
Universal EUD2C4UWEPI EUD2C6UWEPI EUD2C8UWEPI EUD2C10UWEPI
Internally purged internal sample injectors, 1/16" fittings, 0.75 mm bore
Actuator .2 µl .5 µl 1 µl 2 µl
Air A2CI4UWE.2PI A2CI4UWE.5PI A2CI4UWE1PI A2CI4UWE2PI
Universal EUD2CI4UWE.2PI EUD2CI4UWE.5PI EUD2CI4UWE1PI EUD2CI4UWE2PI