Enhancement of valve flow and pressure characteristics in valves and hydraulic systems

1. A valve comprising:

a housing defining a first longitudinal cavity therein;

a sleeve disposed in the first longitudinal cavity coaxial with the housing, wherein the sleeve defines (i) a first port at an end of the sleeve, (ii) a second port disposed on an exterior peripheral surface of the sleeve, and (iii) a second longitudinal cavity therein, wherein an interior peripheral surface of the sleeve defines a first portion that is tapered at a particular angle and a second portion adjacent to the first portion, wherein the second portion comprises two edges forming a corner that defines a seat; and

a poppet mounted within the second longitudinal cavity and configured to move axially therein, wherein:

when the valve is unactuated, the poppet is seated on the seat of the sleeve to preclude flow through the valve from the first port to the second port, and

when the valve is actuated, the poppet moves off the seat to allow fluid to flow from the first port, through a flow area formed between: (i) an exterior peripheral surface of the poppet, and (ii) the first and second portions of the interior peripheral surface of the sleeve, to the second port, wherein the flow area comprises a conical channel formed between the interior peripheral surface of the sleeve and the exterior peripheral surface of the poppet, such that the conical channel has a cross sectional area that varies longitudinally along a length of the conical channel.

2. The valve of claim 1 , wherein the particular angle is a first angle, and wherein the first portion includes a portion that is tapered at a second angle followed by a respective portion tapered at the first angle.

3. The valve of claim 1 , wherein the interior peripheral surface of the sleeve defines a third portion adjacent to the first portion, wherein the third portion is untapered.

4. The valve of claim 3 , wherein the particular angle is a first angle, wherein the interior peripheral surface of the sleeve defines a fourth portion adjacent to the third portion, wherein the fourth portion is tapered at a second angle different from the first angle.

5. The valve of claim 1 , wherein the particular angle is a first angle, wherein the exterior peripheral surface of the poppet is tapered at a second angle that is different from the first angle.

6. The valve of claim 5 , wherein the second angle is smaller than the first angle, such that the conical channel is a converging conical channel.

7. The valve of claim 1 , wherein the poppet comprises a front end disposed adjacent the first port of the sleeve, a back end, and an internal channel configured to communicate the fluid received at the front end through the first port to the back end of the poppet, such that pressure of the fluid is applied on both the front end and the back end of the poppet, and the poppet is pressure-balanced.

8. The valve of claim 7 , wherein the poppet further includes a plurality of radial channels fluidly coupled to the internal channel and configured to communicate the fluid therefrom to a chamber within the housing in which the back end of the poppet is disposed.

9. The valve of claim 1 , wherein the corner is a substantially 90° corner forming the seat.

10. A valve comprising:

a valve body defining (i) a first port, (ii) a second port, and (iii) a longitudinal cavity therein, wherein an interior peripheral surface of the valve body defines a first portion that is tapered at a particular angle and a second portion adjacent to the first portion, wherein the second portion comprises two edges forming a substantially 90° corner that defines a seat; and

a movable element mounted within the longitudinal cavity and configured to move axially therein, wherein:

when the valve is unactuated, the movable element is seated on the seat of the valve body to preclude flow through the valve from the first port to the second port, and

when the valve is actuated, the movable element moves off the seat to allow fluid to flow from the first port, through a flow area formed between: (i) an exterior peripheral surface of the movable element, and (ii) the first and second portions of the interior peripheral surface of the valve body, to the second port, wherein the flow area comprises a conical channel formed between the interior peripheral surface of the valve body and the exterior peripheral surface of the movable element, such that the conical channel has a cross sectional area that varies longitudinally along a length of the conical channel.

11. The valve of claim 10 , wherein the particular angle is a first angle, and wherein the first portion comprises a portion that is tapered at a second angle followed by a respective portion tapered at the first angle.

12. The valve of claim 10 , wherein the interior peripheral surface of the valve body defines a third portion adjacent to the first portion, wherein the third portion is untapered.

13. The valve of claim 12 , wherein the particular angle is a first angle, wherein the interior peripheral surface of the valve body defines a fourth portion adjacent to the third portion, wherein the fourth portion is tapered at a second angle different from the first angle.

14. The valve of claim 10 , wherein the particular angle is a first angle, wherein the exterior peripheral surface of the movable element is tapered at a second angle that is different from the first angle.

15. A hydraulic system comprising:

a source of pressurized fluid;

a reservoir; and

a valve fluidly coupled to the source of pressurized fluid and the reservoir, wherein the valve comprises:

a sleeve defining (i) a first port at an end of the sleeve, wherein the first port is fluid coupled to the source of pressurized fluid, (ii) a second port disposed on an exterior peripheral surface of the sleeve, wherein the second port is fluidly coupled to the reservoir, and (iii) a longitudinal cavity therein, wherein an interior peripheral surface of the sleeve defines a first portion that is tapered at a particular angle and a second portion adjacent to the first portion, wherein the second portion comprises two edges forming a substantially 90° corner that defines a seat; and

a poppet mounted within the longitudinal cavity and configured to move axially therein, wherein:

when the valve is unactuated, the poppet is seated on the seat of the sleeve to preclude flow through the valve from the source of pressurized fluid to the reservoir, and

when the valve is actuated, the poppet moves off the seat to allow pressurized fluid to flow from the first port, through a flow area formed between: (i) an exterior peripheral surface of the poppet, and (ii) the first and second portions of the interior peripheral surface of the sleeve, to the second port, wherein the flow area comprises a conical channel formed between the interior peripheral surface of the sleeve and the exterior peripheral surface of the poppet, such that the conical channel has a cross sectional area that varies longitudinally along a length of the conical channel.

16. The hydraulic system of claim 15 , wherein the particular angle is a first angle, wherein the exterior peripheral surface of the poppet is tapered at a second angle that is different from the first angle.

17. The hydraulic system of claim 15 , wherein the second angle is smaller than the first angle, such that the conical channel is a converging conical channel.