American Air Liquide, Inc.

Michael D Brandt

James J McAndrew

Francois Mermoud

Ronald S Inman

Benjamin Jurcik

The spectrographic sample cell for the analysis of trace impurities in sample gases. The cell is provided with a gas inlet, a gas outlet and a volume for confining the sample gases for analysis. Two mirrors are provided, a first mirror proximate the gas inlet the second mirror proximate the gas outlet, the first mirror having a hole at its radial center. A conically-shaped cell profile is further provided such that the formation of vortices of sample gas is prevented in the cell upstream of or in the region where the analysis of trace impurities is to take place.

Spectroscopic cell design

Gas generating apparatus in which a supply of carrier gas is mixed with an impurity gas that permeates through the membrane of an impurity gas generator. A dopant gas is supplied to the impurity gas generator through a pressure controller which operates in response to a pressure monitor that monitors the pressure of the dopant gas supplied to the impurity gas generator. As the monitored pressure of the supplied dopant gas changes, the pressure of that supplied gas likewise changes in a manner which maintains a substantially constant flow rate of the impurity gas through the membrane to be mixed with a carrier gas.

Gas generating apparatus

An apparatus and method are provided for preparing low concentration gas phase calibration standards. The flows of a standard mixture of impurity in a gas and a dilution gas are controlled by regulating the pressure upstream of respective calibrated orifices. The pressures of the gas flows are regulated such that a critical flow condition is maintained through the orifices. The two flows are then combined to obtain a known dilution of the impurity in the gas.

Critical orifice dilution system and method

A counterflow valve for switching between flowing gas streams without undesirable interaction of the gas with any dead volume area or non-metallic surfaces or both, which valve contains a four-way double ported ball valve having a first and second input and a first and second output, first and second inlet duct, a back pressure regulator, adjustable flow control orifice and a valve outlet duct.

Counterflow valve

A device adapted to generate a gas flow containing a precise amount of impurities. The device comprises a membrane through which an impurity gas peremeates and mixing means to make a mixture of said impurity gas and a vector gas sweeping said membrane. The pressure of said mixture is substantially constant, but adjustable, to enhance the accuracy of the device.

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Chicago, IL, United States of America

Michael D Brandt