Control valve for keeping the rate of flow at a fixed value

Claim 1

A constant-flow fluid regulating valve comprising in combination: a valve casing having inlet and outlet ports at spaced locations therein; spring means mounted coaxially within said valve casing between said inlet and outlet ports; a slide member positioned coaxially within said valve casing normally biased by said spring means towards said inlet port, the lower extremity of said slide member defining a first peripherally extending edge of an intermediate flow passage for fluids upstream of said outlet port, said slide member comprising a cylindrical valve plug, a guide bushing being provided within one end of said valve casing and at least an axially extending portion of said valve plug being positioned concentrically within said guide bushing to slide therewithin, said valve plug having a transversely extending crosspiece secured fixedly therewithin, and the lower circumferentially extending edge of said valve plug comprising said first peripheral edge of said intermediate flow passage; an orifice plate carried by said slide member for movement therewith within said valve casing and having at least one aperture therein for the flow of fluid therethrough from said inlet port; and a guide member mounted fixedly and coaxially within said valve casing downstream of said slide member having a surface defining a second peripherally extending edge axially spaced from said first edge and defining therewith said intermediate flow passage, said guide member including a centering and support element fixedly mounted concentrically in said outlet port, a generally bowl-shaped guide element extending upwardly from said centering and support element and terminating in a circumferentially extending edge comprising said second peripheral surface of said intermediate flow passage, a transverse support plate being positioned within said guide element presenting a seat for one end of said spring means, the other end of said spring means bearing against said crosspiece; whereby the force of said spring means tends to counterbalance fluid pressure differentials acting on the opposed faces of said orifice plate to thereby maintain the cross-sectional area of said intermediate flow passage and the rate of flow of fluid therethrough at a substantially constant value.