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A spool valve and seal having zero leakage includes a spool valve member having a hollow interior translatable within a bore in a valve body with inlet pressure connected through ports to the hollow interior of the spool valve member. A series of radial orifices axially displaced from the inlet port

A spool valve and seal having zero leakage includes a spool valve member having a hollow interior translatable within a bore in a valve body with inlet pressure connected through ports to the hollow interior of the spool valve member. A series of radial orifices axially displaced from the inlet ports communicate the interior with the exterior surface of said spool valve member, the outlets of said orifices terminating in chamfered edges. A seal is positioned adjacent the spool valve member in an annular groove formed in the surface of the bore within which the spool member is translated, the seal being positioned to prevent leakage between the inlet pressure passages and an outlet chamber in said valve body. The preferable seal for this purpose consists of a rubber O-ring in the groove with a Teflon sealing ring overlying the O-ring adjacent the surface of the spool member such that high fluid pressure on the inside of the spool member which is communicated through said orifices to the surface of the sealing ring forces the sealing ring and O-ring into the groove so that when the orifice edges pass the sealing ring they do not abrade the surface of the sealing ring. To avoid having the seal involved in the metering function of the valve, the maximum diameter of the chamfered edges is less than the length of the bore between the seal groove edge nearest the outlet chamber and the outlet chamber in said valve body.

대표청구항 ▼

A spool valve and seal therefor having zero leakage comprising: a valve body having a fluid inlet port and a fluid outlet port and including means defining a bore having axially spaced inlet and outlet passages; a spool valve member reciprocally mounted in said bore, said spool valve member being sh

A spool valve and seal therefor having zero leakage comprising: a valve body having a fluid inlet port and a fluid outlet port and including means defining a bore having axially spaced inlet and outlet passages; a spool valve member reciprocally mounted in said bore, said spool valve member being shiftable between first and second positions respectively wherein in said first position flow is prevented between said inlet and outlet passages and wherein in said second position flow is metered between said inlet and outlet passages; characterized in that said spool valve member includes an internal chamber, a plurality of radial ports through the wall of said spool valve member connecting said inlet passage with said internal chamber, a plurality of radial metering orifices of area substantially smaller than the area of said radial ports through the wall of said spool valve member axially displaced from said radial ports and communicating with said outlet passage when said spool valve member is moved to said second position, said metering orifices being cylindrical and chamfered at the exterior surface of said spool; and seal means for preventing leakage between said inlet and outlet passages when said spool valve member is in said first position, said seal means including an annular groove in the wall of said bore and an O-ring with a low friction sealing ring in said annular groove adjacent said spool valve member, said annular groove being displaced along said bore toward said inlet passage from said outlet passage by a distance greater than the diameter of the chamfered outlets of said radial metering orifices.