Abstract: A method and apparatus for accurately regulating the compressibility of a compressible fluid in a thermoelectrically cooled pumping system having a first heat exchanger for precooling the compressible fluid utilizing cooled fluid which has been outputted from the pump and a second heat exchanger, coupled to the pumphead which incorporates thermoelectric cooling elements, for cooling the compressible fluid immediately prior to being pumped.

Abstract: A valve assembly is provided for controlling pressurized inputs from two separate fluid sources, and in particular to provide enhanced isolation between the sources and to buffer short-term fluctuations in fluid flow. A high pressure chamber is provided which is separated into two chamber portions by a fluid-impervious flexible membrane. A valve, such as a ball valve, having a movable member is positioned in an inlet port in each channel portion, fluid flowing, for a preferred enbodiment, from a fluid source under pressure through the inlet port of a chamber portion, an output port in the portion and a restrictor to a mixer. A pressure differential in the chamber portions deflects the diaphragm to bear against the movable member in the lower pressure chamber portion, closing the valve for this chamber portion before the pressure is sufficient to result in any backflow therethrough.

Abstract: This invnetion relates to a high pressure sealed window assembly which does not result in substantial shear forces being applied to the window, and in particular to such a window assembly for transmitting ultraviolet light in high pressure chromatographic detectors. The window has opposed faces through which light is transmitted and angled surfaces extending toward each other away from corresponding points on the outer edge of the opposed surfaces. Sealing rings, preferably shaped to conform to the shape of the angled surfaces, bear against such surfaces and precompression forces are applied through the sealing rings to precompress the window, preferably over substantially its entire volume. When pressure is applied to one face of the window, the precompression forces must be overcome before such pressure can result in shear forces being developed in the window.

Abstract: A mixing valve for mixing a plurality of liquids comprises a number of valve units corresponding to the number of liquids to be mixed, each consisting of one inlet for liquid, one outlet and one ball valve having a valve ball and a valve seat.

Abstract: A high-pressure viscous damper is proposed, in particular for use in liquid chromatographs, in which two chambers are separated by an elastic partition, and the one chamber receives a fluid to be damped and the other chamber holds a damping fluid. In the chamber holding the damping fluid an insert is provided within the fluid with a selected volume and temperature expansion coefficient so that by the combination of the insert and damping fluid and the volume and wall material of the second chamber a volume compensation is achieved.