Apparatus for producing calibration gases suitable for analytical instrumentation

Apparatus for producing a calibration gas mixture of known composition from a plurality of component gases separately introduced therein and blended together suitable for use in analytical instrumentation, which comprises

• a pressure vessel, forming a gas mixing chamber, sufficient to provide a heat sink for holding the gas temperature substantially stable during the blending of the gases,
• a pump the suction side of which is connected via a suitable conduit with the chamber of said pressure vessel,
• a mix valve connected via a suitable conduit to the chamber of said pressure vessel and via another conduit to the discharge side of said pump, the pump providing a means for circulating gas, and homogenizing the mixture of gases introduced into said chamber when the mix valve is open,
• a vent valve downstream of said chamber and located in a conduit on the discharge side of the pump and upstream of the mix valve for substantially exhausting said gas mixing chamber by operation of said pump when said mix valve is closed,
• a plurality of component gas inlet valves, each of which is in fluid communication via said conduits with said mixing chamber and with a supply source of component gas of the gas mixture for controlling the introduction of the desired component gases into said mixing chamber,
• a product output valve for withdrawal of a product gas blend, and
• pressure transducer means for measuring the pressure of the gases in said mixing chamber, and producing an output signal for control of said pump and valves.