Hydraulic unloading valve

Claim 2

A hydraulic unloading valve for the diversion of hydraulic fluid flow comprising a housing; an inlet in said housing, an outlet in said housing; a chamber in said housing connected to said inlet and said outlet; a recess on opposite side of said chamber from said outlet, a member being slideably mounted in said chamber for shifting between an open position for passing fluid from said inlet to said outlet and a closed position for blocking fluid flow; means for urging said member to the open position, characterized by said member having a resultant force creating means including orifice means for automatically moving said member to the closed position over a range of viscosities of the fluid, said member having a first continuous sealing means with said recess, a second continuous sealing means with said outlet and a third sealing means between said first and second sealing means, said orifice means is between said first and third sealing means to receive fluid in the open position and to be isolated from said inlet in said closed position, said third sealing means in a non-sealing relation in said open position and in sealing relation with the recess to block flow through said orifice means thereby preventing flow of fluid through the valve.

Claim 3

A hydraulic unloading valve for the diversion of hydraulic fluid flow comprising a housing; an inlet in said housing, an outlet in said housing; a chamber in said housing connected to said inlet and said outlet; a recess on the opposite side of said chamber from said outlet, a member being slideably mounted in said chamber for shifting between an open position for passing fluid from said inlet to said outlet and a closed position for blocking fluid flow; means for urging said member to the open position characterized by said member having a resultant force creating means including orifice means for automatically moving said member to the closed position over a range of viscosities of the fluid; said member having a wall with an axial bore for discharge of fluid; an orifice means through said wall to pass fluid for discharge of fluid to said outlet; said member having a first sealing means in continuous sealing relation with said recess to isolate the top of said member from inlet pressure, a second sealing means in continuous sealing relation with said outlet and a third sealing means between said first and second sealing means; means for urging said member to open position being a spring and providing a spring pressure; said orifice means is between said bore and said inlet and between said first and third sealing means; said third sealing means in non-sealing relation in the open position and moving into sealing relation on said member moving to the closed position; said orifice means creating a pressure drop on the flow of fluid in the open position to urge said member to the closed position; said bore creating a bore pressure drop on the flow of fluid therethrough to urge said member to the open position; said pressure drops producing a resultant force which is the combination of the sum thereof times an area comparable to the difference in area between the area of the recess and the area of the outlet less the bore pressure drop times the top area of the member; said member moving to the closed position when said resultant force exceeds said spring pressure, said third sealing means moving into sealing relation with said recess to isolate said orifice means from said inlet and stop the flow of fluid to said outlet thereby holding said member in the closed position under fluid pressure from said inlet.

Claim 4

A hydraulic unloading valve for the diversion of hydraulic fluid flow comprising a housing; an inlet in said housing, an outlet in said housing; a chamber in said housing connected to said inlet and said outlet; a recess on the opposite side of said chamber from said outlet, a member being slideably mounted in said chamber for shifting between an open position for passing fluid from said inlet to said outlet and a closed position for blocking fluid flow; means for urging said member to the open position characterized by said member having a resultant force creating means including orifice means for automatically moving said member to the closed position over a range of viscosities of the fluid; said member having a wall with an axial bore for discharge of fluid; an orifice means through said wall to pass fluid for discharge of fluid to said outlet; said member having a first sealing means in continuous sealing relation with said recess to isolate the top of said member from inlet pressure, a second sealing means in continuous sealing relation with said outlet and a third sealing means between said first and second sealing means; means for urging said member to open position being a spring and providing a spring pressure; said orifice means is between said bore and said inlet and between said first and third sealing means; said third sealing means in non-sealing relation in the open position and moving into sealing relation on said member moving to the closed position; said orifice means creating a pressure drop on the flow of fluid in the open position to urge said member to the closed position; said bore creating a bore pressure drop on the flow of fluid therethrough to urge said member to the open position; said pressure drops producing a resultant force which is the combination of the sum thereof times an area comparable to the difference in area between the area of the recess and the area of the outlet less the bore pressure drop times the top area of the member; said member moving to the closed position when said resultant force exceeds said spring pressure, said third sealing means moving into sealing relation with said recess to isolate said orifice means from said inlet and stop the flow of fluid to said outlet thereby holding said member in the closed position under fluid pressure from said inlet.

Claim 5

A hydraulic valve as set forth in claim 2, wherein said spring means is in said recess to urge said member to the open position and force said member to the open position on the drop of the inlet pressure.

Claim 6

A hydraulic valve as set forth in claim 2, wherein said spring means includes a spring only providing an initial impetus for setting the member from the closed position.

Claim 7

A hydraulic unloading valve comprising a first cylindrical wall forming an inlet passage, a second cylindrical wall forming an outlet passage; a chamber connected to said inlet and outlet passages; a third cylindrical wall forming a recess axially aligned with said outlet passage on the opposite side of said chamber from said outlet passage and of a larger diameter than said outlet passage; a cylindrical sleeve-like member having orifice means and bore means in series and slideably mounted in said chamber and said outlet passage, said member extending through said chamber and moveable between an open position and a closed position; spring means in said recess to urge said member to the open position, said member having first sealing means in continuous sealing relation with said wall of said recess to isolate the top of said member from said inlet passage, a second sealing means in continuous sealing relation with said wall of said outlet passage and a third sealing means between said first and second sealing means; said third sealing means in a non-sealing relation in the open condition and moving into sealing relation with said recess wall when said member moves to the closed position; said bore means having a pressure differential on the flow of fluid therethrough; said orifice means being axially between said first and third sealing means and creating a pressure differential on the flow of fluid therethrough; said orifice means and bore means pressure differentials producing a resultant force which is the combination of the sum of the orifice means and bore pressure differentials times an area corresponding to the difference between the recess and the outlet passage areas less the bore pressure differential times the area of the top of the member whereby said resultant force moves said member against said spring means into said recess when the fluid flow attains a given value over the range of viscosities of the fluid.

Claim 8

A hydraulic unloading valve comprising a first cylindrical wall forming an inlet passage, a second cylindrical wall forming an outlet passage; a chamber connected to said inlet and outlet passages; a third cylindrical wall forming a recess axially aligned with said outlet passage on the opposite side of said chamber from said outlet passage and of a larger diameter than said outlet passage; a cylindrical sleeve-like member having orifice means and bore means in series and slideably mounted in said chamber and said outlet passage, said member extending through said chamber and moveable between an open position and a closed position; spring means in said recess to urge said member to the open position, said member having first sealing means in continuous sealing relation with said wall of said recess to isolate the top of said member from said inlet passage, a second sealing means in continuous sealing relation with said wall of said outlet passage and a third sealing means between said first and second sealing means; said third sealing means in a non-sealing relation in the open condition and moving into sealing relation with said recess wall when said member moves to the closed position; said bore means having a pressure differential on the flow of fluid therethrough; said orifice means being axially between said first and third sealing means and creating a pressure differential on the flow of fluid therethrough; said orifice means and bore means pressure differentials producing a resultant force which is the combination of the sum of the orifice means and bore pressure differentials times an area corresponding to the difference between the recess and the outlet passage areas less the bore pressure differential times the area of the top of the member whereby said resultant force moves said member against said spring means into said recess when the fluid flow attains a given value over the range of viscosities of the fluid.