Free-diaphragm pump

Abstract

A pump for ultra-pure fluids, such as hot, de-ionized water, processing acids, and the like, such as those used in the semiconductor processing industries, is designed to operate at greater than 10 and often 30 or 50 million cycles without failure, and to be failclean. A diaphragm pump maintains a free diaphragm, supported in a contoured chamber for driving and being driven by a piston, able to move radially, rather than absorbing misalignment or distortions. A self-energizing, self-centering, trapezoidal seal captures a constant-thickness diaphragm between a head and body forming the chamber of the pump, separating a body portion and a head portion. An oriented, calendered, multi-layered chlorofluorocarbon diaphragm may be the same material chemically as the body, head, or both. Non-reactive pilots control an operating (motive) fluid, detecting the end-of-stroke whether near the head or near the body. An integrated base controller for the operating fluid supports the apparatus, has a quick exhaust for dumping external-controller air overboard after use, and a bias disk to provide precise, digital, spool positioning within an operational range of pressure differentials. The heads may connect to the body by slip rings, so heads remain registered. Cantilevered portions of the head may absorb secondary creep and provide continued spring loading using exclusively non-reactive materials, no metals, and no elastomers, as a failclean system.