Variable-throttle valve

Claim 1

A variable-throttle valve comprising: a valve body of revolution and a rod, the valve body being rigidly fixed to said rod, said rod extending along the revolution axis of said valve body, said body being provided with a peripheral wall surrounding said rod and defining a passageway for a fluid therebetween, said body and said fluid being movable relative to each other to generate a flow of fluid in a first direction or in a second direction through said passageway according to the direction of relative movement between said body and said fluid, said passageway being of revolution with respect to said axis of said valve body; an annular zone providing a projection on said peripheral wall of said valve body, said projection being directed radially towards the axial rod; a first stop and a second stop carried by said rod in said passageway; and a conical washer which is mounted generally transversely relative to said passageway and is pierced by a central opening through which said rod extends, said washer having a central edge capable of cooperating with each of said stops and a peripheral edge defining a variable cross-sectional area opening with said annular projection; said stops being axially spaced apart a distance greater than the axial thickness of said washer; said washer being capable of free displacement with respect to said body under the action of said flow of fluid through said passageway along said axis of said valve body between a free-flow end position in which said central edge of the washer engages said first stop when said flow of fluid is in said first direction and a throttling end position in which said central edge of the washer engages said second stop when said flow of fluid is in said second direction; said washer being capable of elastic deformation, the deflection and the thickness in a condition of rest of said washer being in a ratio which is higher than 1.4, whereby temporary and elastic reversal of conicity of said washer is possible, said conical washer being oriented in such a manner that said washer is always in said condition of rest when said washer is in said free-flow position, whatever the fluid pressure at said passageway in said first direction of said flow or fluid, whereas when said washer is in said throttling end position, said washer is in said condition of rest when the fluid pressure at said passageway in said second direction of said flow of fluid is below a predetermined threshold value, the conicity of said washer being reversed when said fluid pressure at said passageway in said second direction of said flow of fluid is above said predetermined threshold value; the variable cross-sectional area opening defined between said peripheral edge of said washer and said annular projection having a first value which permits the free flow of fluid through said passageway in said first direction when said washer is at said free-flow end position, said variable cross-sectional area opening having a second value achieved solely by radial clearance between said peripheral edge and said annular projection which constricts the flow of fluid through said passageway to a greatest degree when said washer is at said throttling end position and when said fluid pressure at said passageway in said second direction of said flow of fluid is below said predetermined threshold value, whereby said washer is in said condition of rest, and said variable cross-sectional area opening having a third value which constricts the flow of fluid through said passageway to a degree smaller than said greatest degree when said washer is at said throttling end position and when said fluid pressure at said passageway in said second direction of said flow of fluid is above said predetermined threshold value, whereby the conicity of said washer is reversed.