Valve assembly for a fluid pump

1 . A valve cartridge for a fluid pump, comprising:

a cartridge housing;

a fluid cavity defined in the cartridge housing;

a suction valve assembly, comprising:

a suction valve, configured to control flow into the fluid cavity, having an annular shape defining a central opening, a perimeter edge, and a sealing surface sloped inwardly from the perimeter edge to the central opening;

a guide element connected within the central opening; and

a plurality of axial guide portions, projecting from the suction valve away from the fluid cavity, configured to slide along a surface to guide opening and closing of the suction valve;

a discharge valve configured to control flow out from the fluid cavity, the discharge valve having a valve stem extending through the guide element to define a protruding portion of the valve stem, and a spring retainer on the protruding portion of the valve stem; and

a spring disposed between the spring retainer and the guide element, the spring configured to bias both the suction valve and the discharge valve to closed positions.

2 . The valve cartridge of claim 1 , wherein the spring retainer is a fastener inserted into an end of the valve stem or a retaining clip on the valve stem.

3 . The valve cartridge of claim 1 , wherein the guide element is connected to the suction valve by one or more spokes.

4 . The valve cartridge of claim 1 , wherein an opening of the suction valve is to compress the spring between the guide element and the spring retainer by a movement of the guide element toward the spring retainer, and

wherein an opening of the discharge valve is to compress the spring between the guide element and the spring retainer by a movement of the spring retainer toward the guide element.

5 . The valve cartridge of claim 1 , wherein the suction valve, in an open position, is to allow flow from one or more suction passageways into the fluid cavity, and

wherein the suction valve, in a closed position, is to seal the one or more suction passageways from the fluid cavity, and to allow flow through the fluid cavity via the central opening.

6 . The valve cartridge of claim 1 , wherein the discharge valve is configured to seal an end of the cartridge housing to control flow out from the fluid cavity.

7 . The valve cartridge of claim 1 , wherein the spring surrounds the protruding portion of the valve stem.

8 . The valve cartridge of claim 1 , wherein the plurality of axial guide portions comprises a plurality of axial guide legs projecting from the perimeter edge of the suction valve.

9 . The valve cartridge of claim 1 , wherein the suction valve assembly further comprises a hoop connected between the plurality of axial guide portions.

10 . A valve assembly for a fluid end of a hydraulic fracturing pump, comprising:

a first valve assembly, comprising:

a first valve having an annular shape defining a central opening, a perimeter edge, and a sealing surface sloped inwardly from the perimeter edge to the central opening;

a guide element connected within the central opening; and

a plurality of axial guide legs configured to slide along a surface to guide opening and closing of the first valve;

a second valve assembly, comprising:

a second valve having a valve stem extending through the guide element to define a protruding portion of the valve stem; and

a spring retainer on the protruding portion of the valve stem; and

a spring disposed between the spring retainer and the guide element, the spring configured to bias both the first valve and the second valve, wherein the plurality of axial guide legs extend from the first valve away from the second valve.

11 . The valve assembly of claim 10 , wherein the guide element is connected to the first valve by one or more spokes.

12 . The valve assembly of claim 10 , wherein the spring surrounds the protruding portion of the valve stem.

13 . The valve assembly of claim 10 , wherein the first valve is in a shape of a conical frustum.

14 . The valve assembly of claim 10 , wherein the first valve assembly further comprises a hoop connected between the plurality of axial guide legs.

15 . A hydraulic fracturing pump, comprising:

a fluid end having a fluid end block with a bore, and a plunger configured to reciprocate with respect to the bore;

a power end operably connected to the plunger; and

a valve cartridge, configured for insertion into and removal from the bore as a unit, comprising:

a cartridge housing;

a fluid cavity defined in the cartridge housing; and

a valve assembly configured to control flow through the fluid cavity, wherein the valve assembly comprises:

a first valve assembly, comprising:

a first valve having an annular shape defining a central opening, a perimeter edge, and a sealing surface sloped inwardly from the perimeter edge to the central opening;

a guide element connected within the central opening; and

a plurality of axial guide portions, projecting from the first valve away from the fluid cavity, configured to slide along a surface to guide opening and closing of the first valve;

a second valve assembly, comprising:

a second valve having a valve stem extending through the guide element to define a protruding portion of the valve stem; and

a spring retainer on the protruding portion of the valve stem; and

a spring disposed between the spring retainer and the guide element, the spring configured to bias both the first valve and the second valve to closed positions.

16 . The hydraulic fracturing pump of claim 15 , wherein the first valve is to open during a suction stroke of the plunger to allow flow into the fluid cavity, and

wherein the first valve is to close during a discharge stroke of the plunger to allow flow through the fluid cavity via the central opening.

17 . The hydraulic fracturing pump of claim 15 , wherein the first valve is to close during a suction stroke of the plunger, and

wherein the first valve is to open during a discharge stroke of the plunger to allow flow out from the fluid cavity.

18 . The hydraulic fracturing pump of claim 15 , wherein the guide element is connected to the first valve by one or more spokes.

19 . The hydraulic fracturing pump of claim 15 , wherein an opening of the first valve is to compress the spring between the guide element and the spring retainer by a movement of the guide element toward the spring retainer, and

wherein an opening of the second valve is to compress the spring between the guide element and the spring retainer by a movement of the spring retainer toward the guide element.

20 . The hydraulic fracturing pump of claim 15 , wherein the plurality of axial guide portions comprises a plurality of axial guide legs projecting from the perimeter edge of the first valve, and

wherein the first valve assembly further comprises a hoop connected between the plurality of axial guide legs.