Abstract: An assembly of chromatograph components which operate at a uniform elevated or reduced temperature and perform the functions of sample injection, precolumn backflush, analytical column selection, detection in a reduced mass and volume, and with a reduced surface area for reduced power consumption in accordance with use in a portable gas chromatograph is disclosed. Parts of the assembly including a switching valve assembly, a column plate, a thermal cover and a detector block are thermally-linked and those parts of the assembly which contact the sample including the gas chromatograph columns are maintained at a controlled temperature using, for example, an efficient axial heater, a Peltier cooler or a heat pipe and temperature sensors, thereby increasing analytical confidence.

Abstract: A device for detecting contaminants in returned bottles, particularly in a high-speed bottle line, is disclosed. In the preferred embodiment, a sample chamber is rotated on a carousel unit between top and bottom bulkheads. The surfaces of the bulkheads facing the chamber are flat and substantially parallel, and the chamber has two open ends which face the two bulkheads, respectively. A blast of air is directed into the mouth of the bottle to be sampled, forcing the contents of the bottle through an aperture in the lower bulkhead and into the sample chamber. In the preferred embodiment, the analyzer contains a UV absorption analyzer and a photoionization detector. The carousel unit contains four sample chambers which rotate between a sampling station, the two detectors, and a purge station. The analyzer is controlled by a computer which issues a reject instruction to a bottle reject mechanism if the level of contaminants detected by either detector exceeds a predetermined threshold.

Abstract: A fluid flow control valve for use with chemical fluids where avoidance of contaminants is important, is provided. The valve has a flow control chamber divided into an analytical section and a driver section by a metallic foil membrane operating member, clamped between the peripheral rim of the chamber and the upper wall. The foil membrane is movable in response to driver fluid pressure between open and closed positions. The upper portion of the rim which engages the membrane is of relatively small surface area, and is made of a softer material than that from which the membrane and the upper wall are constructed, .about. thereby providing a very effective means of sealing the membrane periphery to the upper wall when tightly clamped. The membrane is of domed shape, and is formed in situ by deformation of a planar metal foil sealingly clamped in position within the chamber, by application of fluid pressure thereto through a port to the chamber.

Abstract: A fluid control valve arrangement includes a plurality of clusters or pairs of holes extending from one face to the other of a central block. The valves comprise a plurality of deformable blisters formed in a resilient membrane, the blisters positioned so as to coincide with the hole clusters or pairs when the membrane is pressed against a face of the block. The values are closed when the blisters are deformed to an essentially flat shape, advantageously by introducing a high pressure fluid into a cavity above the blisters. The valves are linked together in a desired configuration by grooves formed in the other face of the block.

Abstract: A fluid flow control valve for use with chemical fluids where avoidance of contaminants is important, is provided. The valve has a flow control chamber divided into an analytical section and a driver section by a metallic foil membrane operating member, clamped between the peripheral rim of the chamber and the upper wall. The foil membrane is moveable in response to driver fluid pressure between open and closed positions. The upper portion of the rim which engages the membrane is of relatively small surface area, and is made of a softer material than that from which the membrane and the upper wall are constructed, thereby providing a very effective means of sealing the membrane periphery to the upper wall when tightly clamped. The membrane is of domed shape, and is formed in situ by deformation of a planar metal foil sealingly clamped in position within the chamber, by application of fluid pressure thereto through a port to the chamber.

Abstract: The invention disclosed is a detection system for the detection of gaseous or vaporous ionizable chemical species entrained in air as a carrier gas. The system includes a gas chromatograph column for separating the chemical species to be detected and a photoionization detector designed for use with air as the carrier gas.

Abstract: A gas discharge tube is provided for use in a detector of the type capable of identifying ionizable species in a carrier gas. The tube contains an inert gas at reduced pressure and the gas is excited by an external circuit including a coil about the tube. The circuit generates a radio frequency which excites the gas and emits ultraviolet radiation. This radiation passes through a transversely located window at the end of the tube for ionizing the species in a chamber. Electrodes are also described for use in association with the chamber to sense ionization. These electrodes form part of a sensing circuit.