Abstract: The valve assembly includes a main valve body defining a first inner cylindrical cavity, a support plate positioned above the main valve body, and an upper valve head positioned above the support plate. The upper valve head includes a bottom planar bottom surface and a plurality of discrete conduits, each conduit extending between an outer end and an inner end. The valve assembly further includes a sealing diaphragm interposed between the support plate and the upper valve head. The diaphragm can be engaged by plungers to selectively open or close corresponding gas circuits.

Abstract: The valve assembly includes a main valve body defining a first inner cylindrical cavity, a support plate positioned above the main valve body, and an upper valve head positioned above the support plate. The upper valve head includes a bottom planar bottom surface and a plurality of discrete conduits, each conduit extending between an outer end and an inner end. The valve assembly further includes a sealing diaphragm interposed between the support plate and the upper valve head. The diaphragm can be engaged by plungers to selectively open or close corresponding gas circuits.

Abstract: The micro-plasma emission detector unit is for use with a gas chromatograph. It includes an airtight housing having an internal ionization chamber, a pair of spaced-apart ionization electrodes positioned on opposite sides of the housing, and a set of opposite first and second holding members between which the housing is maintained inside the detector unit. Each electrode is maintained against an outer surface of the housing using a corresponding force-generating mechanism. With the proposed design, the risks of damaging the housing due to the thermal stresses are mitigated and the operating temperature of the detector unit can be increased.

Abstract: The micro-plasma emission detector unit is for use with a gas chromatograph. It includes an airtight housing having an internal ionization chamber and a makeup gas inlet chamber, a pair of spaced-apart ionization electrodes positioned on opposite sides of the ionization chamber, and a permeation device having a semi-permeable membrane. The semi-permeable membrane is at least partially and removably insertable through the makeup gas inlet chamber.