Coaxial bidirectional flow control and relief valves and hydrostat system containing the same

Claim 2

A coaxial flow-directional control valve responsive to differential fluid pressure thereacross arising from flow of fluid in either direction through a flow passage, to direct flow through one of two different valve flow passages and thereby provide a bypass flow function, comprising, in combination, a tubular valve housing; first and second valve seats in the housing; first and second coaxial tubular valve elements nested concentrically and separately reciprocable within the valve housing towards and away from the first and second valve seats, respectively, between closed and open positions, to close and open first and second valve flow passages, respectively, of which one provides a bypass function; a fluid-pressure receiving surface operatively connected to each valve element, urging the first valve element in a first direction towards or away from its valve seat, and the second valve element in a second direction, towards or away from its valve seat; bias means urging each valve element in the opposite direction, the biasing force of the bias means being adjusted to resist movement of each valve element in said direction away from or towards its valve seat except under differential fluid pressure arising from flow and applied to the fluid pressure receiving surface from the first or second flow direction, and each of the valve elements moving in said direction towards or away from its valve seat and opening when flow begins from that direction and closing when flow stops from that direction, the first valve element being responsive to differential fluid pressure arising from flow in the first direction from one side of the valve, and the second valve element being responsive to differential fluid pressure arising from flow in the second direction from the other side of the valve, so that the valve is arranged to open or close in response to differential fluid pressure arising and applied from either direction of flow, and to direct such flow through one of the first and second valve flow passages according to flow direction.

Claim 3

A coaxial flow-directional control valve according to claim 1, in which the valve elements are light in weight and reciprocate between open and closed positions within several milliseconds.

Claim 4

A coaxial flow-directional control valve according to claim 1, in which one of the valve elements is arranged to open under differential fluid pressure from either side of the valve to control flow in a reverse direction through one of the first and second valve flow passages.

Claim 5

A coaxial flow-directional control valve according to claim 1, in which the tubular valve housing has an internal wall along which the valve elements reciprocate between open and closed positions.

Claim 6

A coaxial flow-directional control valve according to claim 4, in which the exterior of the valve element and the internal wall have a close enough clearance to define a fluid-tight seal therebetween.

Claim 7

A coaxial flow-directional control valve according to claim 4, in which at least a portion of the internal wall and the exterior of the valve element are spaced apart; and a sealing means is disposed within that space, providing a fluid-tight seal between the wall and the valve element.

Claim 8

A coaxial flow-directional control valve in accordance with claim 1, in which the bias means is a coil spring.

Claim 9

A coaxial flow-directional control valve in accordance with claim 1, in which the inner tubular valve element has an open central passage for flow of fluid therethrough.

Claim 10

A coaxial flow-directional control valve in accordance with claim 8, in which each tubular valve element has portions of relatively large and relatively small diameter connected by a ledge providing the fluid pressure-receiving surface.

Claim 11

A coaxial flow-directional control valve in accordance with claim 9, in which the portion of lesser diameter of the outer valve element defines a space with the tubular valve housing, within which is disposed a sealing means movable with reciprocation of the valve element within the space, and the portion of lesser diameter of the inner valve element defines a space with the outer valve element, within which is disposed a sealing means movable with reciprocation of the valve element within the space.

Claim 12

A coaxial flow-directional control valve in accordance with claim 1, in which the bias means urges each valve element towards its valve seat, and the fluid pressure-receiving surface is operatively connected to the valve element to urge it away from its valve seat.

Claim 13

A coaxial flow-directional control valve in accordance with claim 11, in which each fluid pressure-receiving surface of each valve element is exposed to fluid pressure both upstream and downstream of the valve, and a fluid pressure differential therebetween arising from flow from either direction moves at least one valve element, overcoming the bias force of the bias means.

Claim 14

A coaxial flow-directional control valve in accordance with claim 1, having a tubular sleeve disposed between the first and second valve elements, and movable with the outer valve element, the inner valve element being reciprocable within the tubular sleeve between closed and open positions towards and away from a valve seat connected to and movable with the tubular sleeve.

Claim 15

A coaxial flow-directional control valve in accordance with claim 13, in which the inner valve element is arranged in its closed position to close off a central fluid passage through the inner valve element, and in its open position to open the fluid passage through the inner valve element.

Claim 16

A coaxial flow-directIonal control valve in accordance with claim 14, in which the tubular sleeve has a cap closing off one end, and the inner valve element seats against the cap to close the fluid passage through the inner valve element.

Claim 17

A coaxial flow directional control valve responsive to differential fluid pressure thereacross arising from flow of fluid in either direction through a flow passage, to direct flow in one of at least three flow paths through one of two different valve flow passages, and thereby provide a bypass flow function in one of at least three flow paths, at least one valve flow passage receiving flow in both forward and reverse flow directions, according to the position of the control valve, comprising, in combination, a tubular valve housing; first and second valve seats in the housing; first and second coaxial valve elements separately reciprocable within the valve housing towards and away from the first and second valve seats, respectively, between closed and open positions, to close and open first and second valve flow passages, respectively, of which one provides a bypass function; a fluid-pressure receiving surface operatively connected to each valve element, urging the first valve element in a first direction towards or away from its valve seat and thereby control flow in a first flow path, and the second valve element in a second direction, towards or away from its valve seat and thereby control flow in a second flow path; one of the valve elements having a fluid-pressure receiving surface receiving pressure from either side of the valve element and being arranged to open under differential fluid pressure from either side of the valve to control flow in either direction through one of the first and second valve flow passages and thereby in addition control flow in a third flow path; bias means urging each valve element in the opposite direction, the biasing force of the bias means being adjusted to resist movement of each valve element in said direction away from or towards its valve seat except under differential fluid pressure arising from flow and applied to the fluid pressure receiving surface from the first or second flow direction, and each of the valve elements moving in said direction towards or away from its valve seat and opening when flow begins from that direction and closing when flow stops from that direction, the first valve element being responsive to differential fluid pressure arising from flow in the first direction from one side of the valve, the second valve element being responsive to differential fluid pressure arising from flow in the second direction from the other side of the valve so that the valve is arranged to open or close in response to differential fluid pressure arising and applied from either direction of flow and to direct such flow in one of the first and second flow paths through one of the first and second valve flow passages according to flow direction, and one of the first and second valve elements in addition being responsive to differential fluid pressure arising from flow from the opposite direction to direct flow in the third flow path through one of the first and second valve flow passages in the opposite direction.

Claim 18

A coaxial flow directional control valve responsive to differential fluid pressure thereacross arising from flow of fluid in either direction through a flow passage, to direct flow in one of at least three flow paths through one of two different valve flow passages, and thereby provide a bypass flow function in one of at least three flow paths, at least one valve flow passage receiving flow in both forward and reverse flow directions, according to the position of the control valve, comprising, in combination, a tubular valve housing; first and second valve seats in the housing; first and second coaxial valve elements separately reciprocable within the valve housing towards and away from the first and second valve seats, respectively, between closed and open positions, to close and open first and second valve flow passages, respectively, of which one provides a bypass function; a fluid-pressure receiving surface operatively connected to each valve element, urging the first valve element in a first direction towards or away from its valve seat and thereby control flow in a first flow path, and the second valve element in a second direction, towards or away from its valve seat and thereby control flow in a second flow path; one of the valve elements having a fluid-pressure receiving surface receiving pressure from either side of the valve element and being arranged to open under differential fluid pressure from either side of the valve to control flow in either direction through one of the first and second valve flow passages and thereby in addition control flow in a third flow path; bias means urging each valve element in the opposite direction, the biasing force of the bias means being adjusted to resist movement of each valve element in said direction away from or towards its valve seat except under differential fluid pressure arising from flow and applied to the fluid pressure receiving surface from the first or second flow direction, and each of the valve elements moving in said direction towards or away from its valve seat and opening when flow begins from that direction and closing when flow stops from that direction, the first valve element being responsive to differential fluid pressure arising from flow in the first direction from one side of the valve, the second valve element being responsive to differential fluid pressure arising from flow in the second direction from the other side of the valve so that the valve is arranged to open or close in response to differential fluid pressure arising and applied from either direction of flow and to direct such flow in one of the first and second flow paths through one of the first and second valve flow passages according to flow direction, and one of the first and second valve elements in addition being responsive to differential fluid pressure arising from flow from the opposite direction to direct flow in the third flow path through one of the first and second valve flow passages in the opposite direction.

Claim 19

A coaxial flow-directional control valve according to claim 16, in which the valve elements are light in weight and reciprocate between open and closed positions within several milliseconds.

Claim 20

A coaxial flow-directional control valve according to claim 16, in which the tubular valve housing has an internal wall along which the valve elements reciprocate between open and closed positions.

Claim 21

A coaxial flow-directional control valve according to claim 18, in which the exterior of the valve element and the internal wall have a close enough clearance to define a fluid-tight seal therebetween.

Claim 22

A coaxial flow-directional control valve according to claim 19, in which at least a portion of the internal wall and the exterior of the valve element are spaced apart; and a sealing mEans is disposed within that space, providing a fluid-tight seal between the wall and the valve element.

Claim 23

A coaxial flow-directional control valve in accordance with claim 19 in which the bias means is a coil spring.

Claim 24

A coaxial flow-directional control valve in accordance with claim 16, in which the first and second coaxial valve elements are tubular and concentric, and the inner tubular valve element has an open central passage for flow of fluid therethrough.

Claim 25

A coaxial flow-directional control valve in accordance with claim 22, in which each tubular valve element has portions of relatively large and relatively small diameter connected by a ledge providing the fluid pressure-receiving surface.

Claim 26

A coaxial flow-directional control valve in accordance with claim 23, in which the portion of lesser diameter of the outer valve element defines a space with the tubular valve housing, within which is disposed a sealing means movable with reciprocation of the valve element within the space, and the portion of lesser diameter of the inner valve element defines a space with the outer valve element, within which is disposed a sealing means movable with reciprocation of the valve element within the space.

Claim 27

A coaxial flow directional control valve in accordance with claim 16 in which the bias means urges each valve element towards its valve seat, and the fluid pressure-receiving surface is operatively connected to the valve element to urge it away from its valve seat.

Claim 28

A coaxial flow directional control valve in accordance with claim 25, in which each fluid pressure-receiving surface of each valve element is exposed to fluid pressure both upstream and downstream of the valve, and a fluid pressure differential therebetween arising from flow from either direction moves at least one valve element, overcoming the bias force of the bias means.

Claim 29

A coaxial flow-directional control valve in accordance with claim 22, having a tubular sleeve disposed between the first and second valve elements, and movable with the outer valve element, the inner valve element being reciprocable within the tubular sleeve between closed and open positions towards and away from a valve seat connected to and movable with the tubular sleeve.

Claim 30

A coaxial flow-directional control valve in accordance with claim 27, in which the inner valve element is arranged in its closed position to close off a central fluid passage through the inner valve element, and in its open position to open the fluid passage through the inner valve element.

Claim 31

A coaxial flow-directional control valve in accordance with claim 28, in which the tubular sleeve has a cap closing off one end, and the inner valve element seats against the cap to close the fluid passage through the inner valve element.