Two position valves
Valco two position valves are available in GC and HPLC versions. Typical applications include sample injection, backflushing, and column switching.
Selectors (multiposition valves)
Instead of the back-and-forth switching of two position valves, selectors step incrementally through continuous revolutions. Selectors are available in low pressure and high pressure versions.
Internally purged versions
The best method for purging leakage across the sealing surfaces and/or diffusion through the sealing material, critical in the measurement of low ppb atmospheric gas concentrations.
Leak testing
Standard test methods ensure valve performance at listed specifications. An optional method utilizes a helium mass spectrometer.
Materials of construction/ specifying a special material
Standard materials are selected for optimum lifetime and compatibility in most applications, with optional materials available for the most demanding situations.