Abstract: A throttle device, especially a throttle valve, is a throttle cage which is a composite of at least two or three layers including an engineering ceramic layer and at least one metal sleeve. In a two-layer embodiment the ceramic is provided on the upstream side and the metal sleeve on the downstream side. In a three-layer configuration the ceramic layer is sandwiched between metal sleeves. The throttle device is particularly adapted to take up shock stresses and alternating stresses namely temperature and or pressure stresses, and also provides the requisite resistance to corrosion, abrasive action, cavitation and the like to materially increase the useful life of the throttle body.

Abstract: A ball cock for fluids carrying abrasive materials has its inlet passage terminating with a smaller cross section than the mouth of a ball passage which, in turn, has a smaller cross section than the mouth of the outlet passage aligned therewith. The cross sectional differences exceed manufacturing and assembly tolerances and have been found to minimize wear of the ball cock.