Piezo-electric Gas Dosers

The piezoelectric gas dosers from Oxford Applied Research are high quality all-metal (no elastomers) UHV compatible dosers which are actuated by means of an internal piezoelectric crystal stack. Application of a voltage to the stack causes it to extend thereby lifting a ceramic plunger which, unenergised, is sealed to the valve seat by a high tension spring.

This design provides fail-safe operation such that in the event of power failure, the valve automatically closes preventing venting of the system. Power is provided for the valve by a compact supply, permitting remote control which is particularly advantageous where the valve is situated in inaccessible or hazardous locations. The linear extension of the piezo-stack with voltage preserves the relationship between leak rate and old-style manual control knob position, as shown in the adjacent graph. Greatest control is provided where it is needed most – in the extremely low flow regime.

PC Control
Computer interface options are available which allow the valve to be integrated into most existing control systems.

Pulsing mode
The valves can be pulsed either manually or using an external TTL trigger. This allows gas pulses of minimum duration 30 ms to be injected into a process or chamber.