Pressure compensated control valve

Claim 2

A control valve comprising, a housing having an inlet port, a service port and a return port communicating with a source of fluid pressure, with apparatus to receive hydraulic fluid for operation thereof and with a reservoir, respectively, a valve member movable axially in said housing and having a chamber formed therein, first and second passage means communicating with each other through said chamber, said member having a neutral position in which said first and second passage means are closed to said ports and being movable in a first direction to place said first passage means in communication with said inlet port and said second passage means in communication with said service port and in a second direction to place said first passage means in communication with said service port and said second passage means in communication with said return port, pressure compensating means disposed in said chamber and including a pressure responsive plunger responsive to differential pressure in said chamber and said service port when said member is moved toward said first position and responsive to pressure differential in said chamber and said return port when said member is moved in said second direction, said pressure differential being operative to move said pressure responsive plunger towards a position varying the opening of said first passage means to maintain said pressure differentials constant.

Claim 3

The combination of claim 1 in which said plunger closes said second passage means in the neutral position of said valve member.

Claim 4

The combination of claim 1 in which said plunger is movable in response to the failure of pressure at said inlet port when said valve is in one of said operating positions to close said second passage means.

Claim 5

The combination of claim 1 in which said second passage means is operative to restrict flow therethrough in accordance with the distance that said valve member has been moved from said neutral position toward said first and second positions.

Claim 6

The combination of claim 1 in which said plunger forms a chamber between said passage means, an auxiliary chamber to one side of said plunger, said auxiliary chamber being in communication with said service port when said member is in said first position and with said return port when said member is in said second position.

Claim 7

A control valve comprising, a housing having a fluid inlet, a pair of fluid service passages and a fluid return passage, a valve member in said housing shiftable in opposite directions from a neutral position isolating said inlet from both said service and return passages toward one or the other of a pair of operating positions in which said inlet communicates with a selected one of said service passages and the other of said service passages communicates with said return passage, a pair of chambers formed in said control valve member and being isolated from each other, said valve member including means to direct fluid flow from said inlet through one of said pair of chambers to one of said service passages serially through first and second control openings and from the other of said service passages through the other of said pair of chambers to said return passage serially through third and fourth control openings, the size of said second and fourth control openings being determined by the extent of movement of said valve member from its said neutral position towards one of said operating positions, a pair of pressure compensating means disposed in said pair of chambers, respectively, and each having a pressure responsive portion for automatically decreasing the size of said first and third openings to decrease the pressure in said chambers in response to an increase in pressure differential between one of said chambers and said service ports through said second opening and between the other of said chambers and said return port through said fourth opening.

Claim 8

A control valve comprising, a housing having a fluid inlet, a pair of fluid service passages and a fluid return passage, a valve member in said housing shiftable in opposite directions from a neutral position isolating said inlet from both said service and return passages toward one or the other of a pair of operating positions in which said inlet communicates with a selected one of said service passages and the other of said service passages communicates with said return passage, a pair of chambers formed in said control valve member and being isolated from each other, said valve member including means to direct fluid flow from said inlet through one of said pair of chambers to one of said service passages serially through first and second control openings and from the other of said service passages through the other of said pair of chambers to said return passage serially through third and fourth control openings, the size of said second and fourth control openings being determined by the extent of movement of said valve member from its said neutral position towards one of said operating positions, a pair of pressure compensating means disposed in said pair of chambers, respectively, and each having a pressure responsive portion for automatically decreasing the size of said first and third openings to decrease the pressure in said chambers in response to an increase in pressure differential between one of said chambers and said service ports through said second opening and between the other of said chambers and said return port through said fourth opening.

Claim 9

The combination of claim 6 in which said pressure compensating means include a plunger slidable in each of said chambers and means continuously biasing said plungers in a direction to increase the size of said first and third openings.

Claim 10

The combination of claim 7 in which said plungers are movable in response to absence of pressure at said inlet to close said second and fourth control openings.

Claim 11

A sectional control valve comprising: a plurality of valve assemblies sandwiched in abutting relation to each other in a bank between a pair of end sections; one of said end sections forming an inlet section having inlet, supply and bypass passages; a plunger regulating the flow of supply fluid from said inlet to said supply and bypass passages; each of said valve assemblies including a housing forming a feeder passage communicating with said supply passage, a service passage and a return passage; a valve member movable in each of said housings from a first position isolating said feeder and service passages toward a second position communicating said feeder and service passages; said control members each having a chamber formed therein, first passage means associated with each chamber and communicating the latter with the associated one of said feeder passages, second passage means communicating each of said chambers with the associated service passage when said valve member is in said second position, a pressure compensating means supported in each of said chambers, means biasing each of said pressure compensating means To a position opening said first passage means, said pressure compensating means being responsive to a pressure in said feeder passages greater than at said service passages to restrict the size of said first passage means to maintain pressure from the associated feeder passage to the corresponding chamber at a predetermined level, each of said second passage means determining the flow of fluid from the associated chamber to said outlet in proportion to the displacement of said valve member from its first position, means communicating said service passages of all of said valve assemblies to one side of said plunger in said inlet section for regulating bypass of fluid pressure from said inlet to said supply passage.

Claim 12

A sectional control valve comprising: a plurality of valve assemblies sandwiched in abutting relation to each other in a bank between a pair of end sections; one of said end sections forming an inlet section having inlet, supply and bypass passages; a plunger regulating the flow of supply fluid from said inlet to said supply and bypass passages; each of said valve assemblies including a housing forming a feeder passage communicating with said supply passage, a service passage and a return passage; a valve member movable in each of said housings from a first position isolating said feeder and service passages toward a second position communicating said feeder and service passages; said control members each having a chamber formed therein, first passage means associated with each chamber and communicating the latter with the associated one of said feeder passages, second passage means communicating each of said chambers with the associated service passage when said valve member is in said second position, a pressure compensating means supported in each of said chambers, means biasing each of said pressure compensating means To a position opening said first passage means, said pressure compensating means being responsive to a pressure in said feeder passages greater than at said service passages to restrict the size of said first passage means to maintain pressure from the associated feeder passage to the corresponding chamber at a predetermined level, each of said second passage means determining the flow of fluid from the associated chamber to said outlet in proportion to the displacement of said valve member from its first position, means communicating said service passages of all of said valve assemblies to one side of said plunger in said inlet section for regulating bypass of fluid pressure from said inlet to said supply passage.

Claim 13

The combination of claim 9 in which at least one of said valve assemblies includes passage means to an adjoining valve assembly, a fluid flow control mechanism disposed in said passage means and being responsive to the differential in pressure in said feeder passage and service passage of said one of said valve assemblies to position said flow control mechanism in a position restricting flow to said adjoining valve assembly.

Claim 14

A control valve of the type having a valve member which is shiftable towards each of a pair of operating positions at opposite sides of a neutral position to direct pressure fluid from an inlet passage to one or the other of a pair of service passages comprising: means directing fluid pressure flow to either service passage to pass serially through first and second variable orifice means, the fluid pressure flow through said second orifice means being determined by the extent to which the valve member is shifted from neutral, said valve member including a first chamber defined therein and a first pressure responsive plunger confined within said chamber and axially movable therein for automatically adjusting the size of said first orifice means, said plunger being acted upon by pressure of fluid at the downstream side of the second orifice means to be urged in a direction to increase the size of said first orifice means, spring means acting on said first plunger to urge the latter in said direction increasing the size of said first orifice, and means for translating the pressure fluid at the upstream side of said second orifice into a force on the plunger tending to move the latter in opposite direction to decrease the size of said first orifice.

Claim 15

A control valve of the type having a valve member which is shiftable towards each of a pair of operating positions at opposite sides of a neutral position to direct pressure fluid from an inlet passage to one or the other of a pair of service passages comprising: means directing fluid pressure flow to either service passage to pass serially through first and second variable orifice means, the fluid pressure flow through said second orifice means being determined by the extent to which the valve member is shifted from neutral, said valve member including a first chamber defined therein and a first pressure responsive plunger confined within said chamber and axially movable therein for automatically adjusting the size of said first orifice means, said plunger being acted upon by pressure of fluid at the downstream side of the second orifice means to be urged in a direction to increase the size of said first orifice means, spring means acting on said first plunger to urge the latter in said direction increasing the size of said first orifice, and means for translating the pressure fluid at the upstream side of said second orifice into a force on the plunger tending to move the latter in opposite direction to decrease the size of said first orifice.

Claim 16

The control valve of claim 11 wherein said first and second orifice means communicate with said chamber.

Claim 17

The control valve of claim 12 in which said plunger is slidably mounted in said chamber.

Claim 18

The control valve of claim 11 and further comprising valve means formed by said plunger to close said second orifice means in response to failure of fluid pressure at said inlet.

Claim 19

The control valve of claim 11 wherein said valve member is movable to a position directing fluid pressure returning to the other of said service passages to a return passage, said member forming a second chamber therein, additional means directing pressure fluid to pass serially through third and fourth variable orifice means, said second chamber including a second pressure compensating plunger confined within said chamber and axially movable therein for automatically adjusting the size of said third orifice, said second plunger being acted upon by pressure of fluid at the upstream side of said third orifice to urge said second plunger in a direction to decrease the size of said third orifice.

Claim 20

The control valve of claim 15 in which said plungers are movable independently of each other.

Claim 21

The control valve of claim 15 in which said valve member forms a pair of chambers isolated from each other, said plungers being independently slidably mounted in said chambers, respectively.

Claim 22

A control valve having a body with a valve member shiftable to a selected operating position at either side of a neutral position at which fluid is directed from a fluid pressure inlet passage to a Selected one of a pair of service passages, means communicating fluid from said inlet to said selected one of said service passages serially through first and second variable orifices, a chamber formed in said valve member and communicating said first and second orifices, said second variable orifice through which pressure fluid flow from said chamber to a selected one of said service passages regulating the flow of fluid in an amount depending upon the extent of movement of said valve member from said neutral position, a compensating valve mechanism for automatically adjusting the fluid flow through said first variable orifice, said compensating valve mechanism including a pressure responsive plunger slidable in said chamber to automatically enlarge and contract said adjustable orifice depending upon the direction in which said compensating plunger is moved, biasing means urging said plunger in the direction to enlarge said adjustable orifice, means for translating pressure of fluid established downstream from said second orifice into force on the plunger tending to move the latter in a direction to enlarge said first adjustable orifice, and means for translating pressure of fluid obtained upstream from said second orifice into a force on said plunger tending to move it in a direction to restrict said first orifice.

Claim 23

A control valve having a body with a valve member shiftable to a selected operating position at either side of a neutral position at which fluid is directed from a fluid pressure inlet passage to a Selected one of a pair of service passages, means communicating fluid from said inlet to said selected one of said service passages serially through first and second variable orifices, a chamber formed in said valve member and communicating said first and second orifices, said second variable orifice through which pressure fluid flow from said chamber to a selected one of said service passages regulating the flow of fluid in an amount depending upon the extent of movement of said valve member from said neutral position, a compensating valve mechanism for automatically adjusting the fluid flow through said first variable orifice, said compensating valve mechanism including a pressure responsive plunger slidable in said chamber to automatically enlarge and contract said adjustable orifice depending upon the direction in which said compensating plunger is moved, biasing means urging said plunger in the direction to enlarge said adjustable orifice, means for translating pressure of fluid established downstream from said second orifice into force on the plunger tending to move the latter in a direction to enlarge said first adjustable orifice, and means for translating pressure of fluid obtained upstream from said second orifice into a force on said plunger tending to move it in a direction to restrict said first orifice.

Claim 24

The combination of claim 18 in which said plunger is slidably supported in said chamber.

Claim 25

The combination of claim 19 in which means biasing said plunger is a spring urging said plunger with a predetermined force and in which the pressure obtained upstream of said second orifice and in said chamber is maintained at a constant to equalize said predetermined force.