CN111795166A

CN111795166A - Valve, valve assembly and application thereof

Info

Publication number: CN111795166A
Application number: CN202010253760.9A
Authority: CN
Inventors: K.布罗克; G.德威克基; R.西纳帕; J.辛格利
Original assignee: Kennametal Inc
Current assignee: Kennametal Inc
Priority date: 2019-04-04
Filing date: 2020-04-02
Publication date: 2020-10-20
Also published as: CA3072547A1

Abstract

The invention discloses a valve, a valve assembly and application thereof. Valves and valve assemblies are described herein that employ an architecture that can reduce the degrading wear mechanisms, thereby extending the useful life of the assembly. In one aspect, a valve includes a head including a circumferential surface and a valve seat mating surface comprising a cemented carbide. Leg members extend from the head, wherein a thickness of one or more of the leg members tapers in a direction away from the head to induce laminar fluid flow around the head. In some embodiments, the cemented carbide is an inlay attached to the valve head.

Description

Valve, valve assembly and application thereof

Data of related applications

This application is a continuation-in-part application of U.S. patent application serial No. 16/119,513 filed on 31/8/2018.

Technical Field

The present invention relates to valves and valve assemblies, and in particular, to valves and valve assemblies for fluid-end applications.

Background

The valves and associated valve assemblies play a key role in the fluid end of high pressure pumps incorporating positive displacement pistons in multiple cylinders. The operating environment of the valve is often harsh due to the high pressures and cyclic impact between the valve body and the valve seat. These harsh operating conditions may cause premature failure and/or leakage of the valve assembly. In addition, the fluid flowing through the fluid end and contacting the valve assembly may contain a high concentration of particulate matter from the hydraulic fracturing operation. Additionally, one or more acids and/or other corrosive materials may be present in the fluid/particulate mixture. In hydraulic fracturing, a slurry of particles is used to maintain crack openings in the geological formation after hydraulic pressure is released from the well. In some embodiments, alumina particles are used in the slurry due to their higher compressive strength relative to silica particles or sand. The particulate slurry can cause significant wear to the contact surfaces of the valve and valve seat. In addition, slurry particles may become trapped in the valve seal cycle, resulting in further performance degradation of the valve assembly.

Disclosure of Invention

In view of these shortcomings, valves and valve assemblies are described herein that employ architectures that can reduce the degrading wear mechanisms, thereby extending the useful life of the assembly. In one aspect, a valve includes a head portion including a circumferential surface and a valve seat mating surface. Leg members extend from the head, wherein a thickness of one or more of the leg members tapers in a direction away from the head to induce laminar fluid flow around the head. The valve may further include a seal coupled to the circumferential surface of the head. In some embodiments, an outer surface of the seal exhibits a radius of curvature that maintains laminar fluid flow around the valve. Additionally, in some embodiments, the seal may overlap a portion of the valve seat mating surface.

In another aspect, a valve includes a head portion including a circumferential surface and a valve seat mating surface. A seal is coupled to the circumferential surface, wherein the seal is angled with respect to the valve seat mating surface to establish a primary seat contact area on the seal. The primary seat contact area may have a location proximate an outer circumferential surface of the seal. As further described herein, compressive stress may be concentrated at the main seat contact area when the valve is mated with the valve seat. In some embodiments, the seal overlaps a portion of the valve seat mating surface.

In another aspect, a valve assembly is described herein. In some embodiments, a valve assembly includes a valve seat and a valve in reciprocating contact with the valve seat, the valve including a head portion including a circumferential surface and a valve mating surface. Leg members extend from the head, wherein a thickness of one or more of the leg members tapers in a direction away from the head to induce laminar fluid flow around the head. The valve may further include a seal coupled to the circumferential surface of the head. In some embodiments, an outer surface of the seal exhibits a radius of curvature that maintains laminar fluid flow around the valve. In some embodiments, the seal may also overlap a portion of the valve seat mating surface. Additionally, the seal may be angled with respect to the valve seat mating surface to establish a primary seat contact area on the seal. In some embodiments, the primary base contact area is located proximate an outer circumferential surface of the seal. The primary contact area on the seal may exhibit a compressive stress concentration when mated with the valve seat.

In some embodiments, the valve seat may include a body including a first section for insertion into a fluid passage of a fluid end; and a second segment extending longitudinally from the first segment, the second segment including a recess in which the wear insert is positioned. The wear insert serves as a valve mating surface. In some embodiments, the wear insert exhibits a compressive stress condition. Further, the first and second sections of the valve seat may have the same outer diameter or different outer diameters. For example, the outer diameter of the second section may be greater than the outer diameter of the first section. In other embodiments, the valve seat may be formed from a single alloy composition, thereby avoiding the wear insert.

In another aspect, methods of controlling fluid flow are also described herein. In some embodiments, a method of controlling fluid flow includes providing a valve assembly including a valve seat and a valve in reciprocating contact with the valve seat. The valve includes a head portion including a circumferential surface and a valve seat mating surface. Leg members extend from the head, wherein a thickness of one or more of the leg members tapers in a direction away from the head. The valve is out of contact with the valve seat to cause fluid flow through the assembly, wherein the one or more tapered leg members cause laminar fluid flow around the head. The valve then cooperates with the valve seat to prevent fluid flow through the valve. In some embodiments, a seal is coupled to the circumferential surface of the head. The seal may have a radius of curvature that maintains laminar fluid flow around the valve.

These and other embodiments are further described in the detailed description below.

Drawings

FIG. 1 illustrates a main seat contact area of a seal engaged with a valve seat, according to some embodiments.

FIG. 2 illustrates a stress distribution of a valve seal in contact with a valve seat according to some embodiments.

Fig. 3 illustrates a front view of a valve according to some embodiments.

Fig. 4 is a sectional view B of fig. 3.

Fig. 5 is a cross-sectional view of the valve of fig. 3 taken along line a-a.

Fig. 6 is a sectional view C of fig. 5.

Fig. 7A through 7F illustrate various cross-sectional seal geometries according to some embodiments.

Fig. 8 is a fluid flow modeling of the valve in fig. 3-6 illustrating laminar flow around the valve head, according to some embodiments.

FIG. 9 is a cross-sectional schematic view of a valve seat according to some embodiments.

FIG. 10 is a cross-sectional schematic view of a valve seat according to some embodiments.

FIG. 11 is a bottom plan view of a valve seat according to some embodiments.

FIG. 12 is a top plan view of a valve seat according to some embodiments.

FIG. 13 is a perspective view of a valve seat according to some embodiments.

FIG. 14 is a side elevational view of a valve seat according to some embodiments.

FIG. 15 is a cross-sectional view of a sintered cemented carbide inlay according to some embodiments.

FIG. 16 is a cross-sectional view of a valve seat including a sintered cemented carbide inlay connected to an alloy body or sleeve according to some embodiments.

FIG. 17 is a cross-sectional view of a valve seat including a sintered cemented carbide inlay connected to an alloy body or sleeve according to some embodiments.

Detailed Description

The embodiments described herein may be understood more readily by reference to the following detailed description and examples. However, the elements, devices, and methods described herein are not limited to the specific embodiments presented in the detailed description and examples. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Many modifications and adaptations to those skilled in the art will readily occur without departing from the spirit and scope of the present invention.

I.Valve gate

The valves described herein employ an architecture that can reduce degraded wear paths, thereby extending the useful life of the valve. In one aspect, a valve includes a head portion including a circumferential surface and a valve seat mating surface. Leg members extend from the head, wherein a thickness of one or more of the leg members tapers in a direction away from the head to induce laminar fluid flow around the head. The leg members may have any taper angle consistent with inducing laminar fluid flow around the head. For example, one or more of the legs may have a taper angle of 1 to 10 degrees. In other embodiments, the leg taper angle may be 2 to 5 degrees. The leg members of the valve may exhibit the same taper angle or different taper angles. The taper angle of each leg member can be individually adjusted depending on the fluid flow environment of the valve. Alternatively, the taper angles of the leg members may be adjusted in conjunction with one another to induce a laminar fluid flow around the head. The leg member may also include rounded and/or flat surfaces. For example, one or more edges of the leg member may be rounded.

The valve may include any desired number of leg members. The number of leg members may be selected based on a number of considerations, including, but not limited to, the fluid flow environment of the valve and the structural parameters of the assembly incorporating the valve. The valve may comprise 3 to 6 leg members. In some embodiments, the leg members of the valve may exhibit equidistant radial spacing or offset. In other embodiments, the radial spacing between the leg members may be variable.

The leg member extends from a bottom surface of the valve head. The intermediate body member or stem may reside between the bottom surface of the head and the leg member. The leg members may extend radially from the intermediate body member. In some embodiments, the leg member extends radially at an angle of 45 to 80 degrees relative to a longitudinal axis of the valve. In some embodiments, the leg member extends radially at an angle of 60 to 70 degrees relative to a longitudinal axis of the valve. Each of the leg members may extend radially at the same angle. Alternatively, the leg members may extend radially at different angles relative to the longitudinal axis. Additionally, a transition region between the bottom surface of the valve head and the intermediate body member may exhibit a radius of curvature. The radius of curvature may be in the range of 0.25mm to 5 mm. In some embodiments, the radius of curvature of the transition region is in the range of 0.5mm to 2 mm. The radius of curvature may help to maintain laminar fluid flow around the head.

The valve may further include a seal coupled to a circumferential surface of the head. In some embodiments, the circumferential surface defines an annular groove that engages the seal, the annular groove including a top surface and a bottom surface. The top surface of the annular groove may extend radially beyond the bottom surface. Additionally, the bottom surface of the annular groove may transition to the valve seat mating surface. In some embodiments, the transition between the bottom surface of the groove and the mating surface of the valve seat has a radius of curvature that is less than the radius of curvature of the annular groove.

The outer surface of the seal member may have a radius of curvature that maintains laminar fluid flow around the valve head. Thus, the tapered leg member may work in conjunction with the seal member and the intermediate body member to provide laminar fluid flow around the valve head. In some embodiments, the seal overlaps a portion of the valve seat mating surface. In other embodiments, the seal terminates at the end wall of the valve seat mating surface and does not overlap a portion of the valve seat mating surface. The seal may comprise any material consistent with the sealing of the valve assembly in a high pressure fluid environment, such as those materials encountered in fluid ends used in hydraulic fracturing operations. In some embodiments, the seal comprises a polymeric material, for example, polyurethane or a polyurethane derivative. In other embodiments, the seal may comprise one or more elastomeric materials, alone or in combination with other polymeric materials.

Notably, the seal may form an angle (α) with the valve seat mating surface. An angle (α) formed with the valve seat mating surface may establish a primary area on the seal for contacting the valve seat. This main seat contact area may be located near the outer circumferential surface of the seal. The radial position of the main seat contact area can be varied by varying the angle (α) formed by the seal and the valve seat mating surface. For example, the main base contact area may move radially outward on the seal by increasing the angle or radially inward by decreasing the angle. For example, the angle (α) between the seal and the valve seat mating surface may be in the range of 5 degrees to 30 degrees. In some embodiments, the value of α is selected from table I.

TABLE I values of alpha (degrees)

5-25
	10-20
8-15
	12-17

The main base contact area is typically a first area of the seal to contact the valve seat during operation of a valve assembly in which the valve is employed. When the valve is mated with the valve seat, the compressive stress may be highest or concentrated in the main seat contact area. By establishing the primary seat contact area, the stress relief and/or dissipation characteristics of the seal can be controlled. In some embodiments, for example, the primary base contact area is located proximate to an outer circumferential surface of the seal. By occupying this radially outward position, the primary base contact area can quickly dissipate stress concentrations or risers due to the short energy transfer distance from the outer surface of the seal. In this way, stress risers at internal radial locations are avoided and seal life is enhanced. This technical solution is counter-intuitive based on the general stress management principle, where stress risers should be avoided and the stress spread evenly over the entire area of the seal.

As described herein, the valve includes a valve seat mating surface. The valve seat mating surface contacts the valve seat when a valve assembly employing the valve is in a closed position. In some embodiments, the valve seat mating surface comprises the same alloy that forms the remainder of the valve. Alternatively, the valve seat mating surface may include a wear-resistant cladding. For example, the wear-resistant cladding may comprise a wear-resistant alloy. Suitable wear resistant alloys include cobalt-based alloys and nickel-based alloys. In some embodiments, the cobalt-based alloy of the cladding has composition parameters selected from table II.

TABLE II cobalt-based alloys

Element(s)	Amount (wt%)
		Chromium (III)	5-35
Tungsten	0-35
		Molybdenum (Mo)	0-35
Nickel (II)	0-20
		Iron	0-25
Manganese oxide	0-2
		Silicon	0-5
Vanadium oxide	0-5
		Carbon (C)	0-4
Boron	0-5
		Cobalt	The rest part

In some embodiments, the cobalt-based alloy cladding has composition parameters selected from table III.

TABLE III cobalt-based alloy cladding

In some embodiments, the nickel-base alloy clad layer may have composition parameters selected from table IV.

TABLE IV- -Nickel base alloys

In some embodiments, for example, the nickel-base alloy clad layer comprises 18 to 23 wt.% chromium, 5 to 11 wt.% molybdenum, 2 to 5 wt.% of the sum of niobium and tantalum, 0 to 5 wt.% iron, 0.1 to 5 wt.% boron, and the balance nickel. Alternatively, the nickel-base alloy clad layer includes 12 to 20 wt% chromium, 5 to 11 wt% iron, 0.5 to 2 wt% manganese, 0 to 2 wt% silicon, 0 to 1 wt% copper, 0 to 2 wt% carbon, 0.1 to 5 wt% boron, and the balance nickel. Further, the nickel-base alloy clad layer may include 3 to 27 wt% chromium, 0 to 10 wt% silicon, 0 to 10 wt% phosphorus, 0 to 10 wt% iron, 0 to 2 wt% carbon, 0 to 5 wt% boron, and the balance nickel.

In some embodiments, the cobalt-based cladding layer and/or the nickel-based cladding layer may be produced by a sintered powder metallurgy technique. In other embodiments, the cobalt-based cladding layer and the nickel-based cladding layer may be produced according to laser cladding or plasma transferred arc techniques. In addition, the wear-resistant cladding for the mating surface of the valve may have any desired thickness. For example, the cladding thickness may be selected from table V.

TABLE V- -cladding thickness

≥50μm
	≥100μm
100 to 200 μm
	500 μm to 1mm

The cobalt-based or nickel-based cladding may also include hard particles. In such embodiments, the hard particles become entrapped in the alloy matrix formed during sintering or melting of the powder alloy. Suitable hard particles may include particles of metal carbides, metal nitrides, metal carbonitrides, metal borides, metal suicides, cemented carbides, as-cast cemented carbides, intermetallics or other ceramics, or mixtures thereof. In some embodiments, the metallic elements of the hard particles comprise aluminum, boron, silicon, and/or one or more metallic elements selected from groups IVB, VB, and VIB of the periodic table. Groups of the periodic table described herein are identified according to CAS designation.

In some embodiments, for example, the hard particles comprise carbides of tungsten, titanium, chromium, molybdenum, zirconium, hafnium, tantalum, niobium, rhenium, vanadium, boron, or silicon, or mixtures thereof. The hard particles may also comprise nitrides of aluminum, boron, silicon, titanium, zirconium, hafnium, tantalum or niobium, including cubic boron nitride, or mixtures thereof. Additionally, in some embodiments, the hard particles include borides, e.g., titanium diboride, B₄C or tantalum borides, or silicides, e.g. MoSi₂Or Al₂O₃- -SiN. The hard particles may include crushed cemented carbide, crushed carbides, crushed nitrides,crushed borides, crushed silicides, or other ceramic particle reinforced metal matrix composites, or combinations thereof. For example, the crushed cemented carbide particles may have 2 to 25 wt% metal binder. In addition, the hard particles may include intermetallic compounds, such as nickel aluminide.

The hard particles may be of any size consistent with the objectives of the present invention. In some embodiments, the hard particles have a size distribution in a range from about 0.1 μm to about 1 mm. The hard particles may also exhibit bi-modal or multi-modal size distributions. The hard particles may have any desired shape or geometry. In some embodiments, the hard particles have a spherical, ellipsoidal, or polygonal geometry. In some embodiments, the hard particles have an irregular shape, including shapes with sharp edges.

The hard particles may be present in the alloy cladding described herein in any amount not inconsistent with the objectives of the present invention. The hard particle loading of the cladding may vary depending on a number of considerations, including, but not limited to, the desired hardness, wear resistance, and/or toughness of the cladding. In some embodiments, the hard particles are present in the cladding in an amount of 0.5 wt% to 40 wt%. In some embodiments, the hard particles are present in the cladding in an amount of 1 to 20 wt% or 5 to 20 wt%.

In some embodiments, the cladding is applied directly to the valve seat mating region of the valve. As described herein, the cladding may be applied by powder metallurgy techniques including sintering. In other embodiments, the cladding may be applied by laser cladding or plasma transferred arc. Alternatively, the cladding may be provided as an inlay. For example, the envelope may be pre-formed to a desired size to be embedded, wherein the inlay seats in a recess on the valve body to provide the valve seat mating surface. The inlay may have any of the compositional characteristics described above for the valve seat mating surface, including cobalt-based alloys, nickel-based alloys, and/or hard particles. The valve seat-mating inlay may be press-fit and/or metallurgically bonded to the valve body via a braze alloy.

In some embodiments, the valve seat mating surface comprises cemented carbide. The cemented carbide may be applied as a coating to the valve seat mating surface. Alternatively, the sintered cemented carbide may be applied to the valve head as an inlay. For example, the sintered cemented carbide inlay may be manufactured separately and brazed or press-fitted to the valve head. In other embodiments, the sintered cemented carbide inlay is attached to a base or substrate, and the base or substrate is connected to the valve head. The inlay may be coupled to the base or substrate by any desired method. For example, the inlay may be brazed or mechanically mated to the substrate. Additionally, the base or substrate may be attached to the valve head via various mechanisms, including, but not limited to, welding, mechanical locking such as a press-fit or shrink-fit, and/or the use of adhesives. The valve head may include a recess or other structure for receiving a sintered cemented carbide insert. In some embodiments, the sintered cemented carbide inlay is provided as a single, integral piece. The sintered cemented carbide inlay may also be provided as a plurality of radial segments. Any number of radial segments is contemplated. In some embodiments, providing a sintered cemented carbide inlay as multiple radial segments may extend inlay service life by inhibiting crack propagation and/or other failure modes that may cause premature failure of an inlay having a single piece construction. For example, degradation and/or failure of one radial segment may not have any effect on the performance of other radial segments of the inlay.

The sintered cemented carbide of the inlay forming the mating surface of the valve seat may comprise tungsten carbide (WC). In some embodiments, WC may be present in the cemented carbide in an amount of at least 70 wt.%, or in an amount of at least 80 wt.%. Additionally, the metallic binder of the cemented carbide may comprise cobalt or a cobalt alloy. For example, cobalt may be present in the sintered cemented carbide in an amount in the range of 3 to 30 wt.%. In some embodiments, the cobalt is present in the sintered cemented carbide in an amount of 5 to 12 wt% or 6 to 10 wt%. Further, the sintered cemented carbide may exhibit a binder-rich zone beginning at and extending inwardly from the surface of the substrate. The sintered cemented carbide of the clad valve mating surface and/or inlay may also include one or more additives, for example, one or more of the following elements and/or compounds thereof: titanium, niobium, vanadium, tantalum, chromium, zirconium and/or hafnium. In some embodiments, titanium, niobium, vanadium, tantalum, chromium, zirconium, and/or hafnium forms solid solution carbides with WC of the cemented carbide. In such embodiments, the cemented carbide may include one or more solid solution carbides in an amount in the range of 0.1 wt.% to 5 wt.%.

In some embodiments, the sintered cemented carbide of the clad valve mating surface or inlay may have a surface roughness (R) of 1 μm to 15 μm_a). Surface roughness (R) of sintered cemented carbide_a) It may be 5 μm to 10 μm. The surface roughness of the sintered cemented carbide forming the valve mating surface may be obtained via mechanical operations including, but not limited to, grinding and/or grit blasting techniques. Further, the sintered cemented carbide of the valve mating surface may exhibit a compressive stress condition of at least 500MPa or at least 1 GPa.

FIG. 1 illustrates a main seat contact area of a seal engaged with a valve seat, according to some embodiments. As illustrated in fig. 1, the primary seat contact area 11 (circled) is located near or adjacent to the outer circumferential surface 12 of the seal 10. Fig. 2 illustrates the stress distribution of the seal 10 upon contact with the seat 15. The compressive stress concentration is highest in the main base contact region 11 and can be dissipated quickly through the adjacent outer surface 12 of the seal 10.

Fig. 3 illustrates a front view of a valve according to some embodiments. The valve 30 includes a head 31 and a leg member 32 extending from the head 31. In the embodiment of fig. 3, there are three leg members 32 with equidistant radial spacing. The thickness of each leg member 32 tapers in a direction away from the head 31 to create a laminar fluid flow around the head 31. Fig. 4 is a sectional view B of fig. 3. The tapering of leg member 32 and the rounded edges 33 of leg member 32 are apparent. The valve of fig. 3 further includes a seal 34 attached to the outer circumferential surface of the head 31. Fig. 5 is a sectional view of the valve taken along line a-a of fig. 3. In cross-section, the seal 34 engages an annular groove 35 having a top surface 35a and a bottom surface 35 b. Having a radius of curvature R₁Connecting the top surface 35a and the bottom surface 35 b. In addition, the top surface 35a extends radially beyond the bottom surface 35 b. In the embodiment of fig. 5, the bottom surface 35b via a radius of curvature R₂To the valve seat mating surface 37. In some embodiments, R₁Greater than R₂. As described above, the valve seat mating surface 37 includes the wear-resistant cladding 37 a. In the embodiment of fig. 3, the valve seat mating surface 37 exhibits a frustoconical geometry. The seal 34 forms an angle (α) with the valve seat mating surface 37. As described above, the angle (α) may establish a primary base contact area for the seal 34. Fig. 6 is a sectional view C of fig. 5 providing enlarged detail of the annular groove 35 and associated seal 34. The outer surface of the seal 34a may exhibit a radius of curvature R₃For maintaining a laminar fluid flow around the head 31.

Referring again to fig. 5, leg members 32 extend radially from intermediate body member 39. Establishing a radius of curvature R between the bottom surface of the head 31 and the intermediate body member 39₃The curved transition zone 40. This transition zone 40 may have a radius of curvature that assists the laminar fluid flow around the head 31. In other embodiments, the transition region 40 is not curved. Fig. 7A through 7F illustrate cross-sectional views of various seal geometries and designs according to some embodiments.

Fig. 8 illustrates fluid flow modeling of the valve illustrated in fig. 3-6. As illustrated in fig. 8, leg members 32 induce a laminar fluid flow around head 31. The curved transition zone 40 and the curved outer surface 34a of the seal 34 help to maintain laminar fluid flow.

In another aspect, a valve includes a head portion including a circumferential surface and a valve seat mating surface. A seal is connected to the circumferential surface and is angled with respect to the valve seat mating surface to establish a primary seat contact area on the seal. The primary seat contact area may be located proximate an outer circumferential surface of the seal. In some embodiments, the seal overlaps a portion of the valve seat mating surface. The valve and associated main base contact region may have any of the compositions, characteristics, and/or functions described above in this section I. For example, the valve and seal may exhibit the architecture and functionality described herein in fig. 1-8.

II.Valve assembly

In another aspect, a valve assembly is described herein. In some embodiments, a valve assembly includes a valve seat and a valve in reciprocating contact with the valve seat, the valve including a head portion including a circumferential surface and a valve mating surface. Leg members extend from the head, wherein a thickness of one or more of the leg members tapers in a direction away from the head to induce laminar fluid flow around the head. The valve may further include a seal coupled to a circumferential surface of the head. In some embodiments, the outer surface of the seal exhibits a radius of curvature that maintains laminar fluid flow around the valve. In some embodiments, the seal may also overlap a portion of the valve seat mating surface. Additionally, the seal may be angled with respect to the valve seat mating surface to establish a primary seat contact area on the seal. In some embodiments, the primary base contact area is located proximate an outer circumferential surface of the seal. The primary contact area on the seal may exhibit a compressive stress concentration when mated with the valve seat. The valve for the valve assembly may have any of the architectures, characteristics, and/or compositions described in section I above. For example, the valve may exhibit the architecture and functionality as described in fig. 1-8 herein.

In some embodiments, a valve seat may include a body including a first segment for insertion into a fluid passage of a fluid end and a second segment extending longitudinally from the first segment, the second segment including a recess in which a wear insert is located, wherein the wear insert includes a valve mating surface. In some embodiments, the wear insert exhibits a compressive stress condition. Further, the first and second sections of the valve seat may have the same outer diameter or different outer diameters. For example, the outer diameter of the second section may be greater than the outer diameter of the first section. In other embodiments, the valve seat may be formed from a single alloy composition, thereby eliminating the wear insert.

Referring now to fig. 9, the valve seat 10 includes a first section 11 for insertion into a fluid passage of a fluid end. In the embodiment of fig. 9, the first section 11 comprises a tapered outer surface 12 and an inner surface 13 substantially parallel to a longitudinal axis 14 of the base 10. In some embodiments, the inner surface 13 may also be tapered. The tapered outer surface 12 may exhibit a variable outer diameter D1 of the first section 11. Alternatively, the outer surface 12 of the first section 11 is not tapered and remains parallel to the longitudinal axis 14. In this embodiment, the first section 11 has a static outer diameter D1. The outer surface 12 of the first section may also include one or more recesses 15 for receiving O-rings. One or more O-rings may help to seal with the walls of the fluid channel.

The second section 16 extends longitudinally from the first section 11. The second section has an outer diameter D2 that is greater than the outer diameter D1 of the first section 11. In the embodiment of fig. 9, the ring 19 surrounding the second section 16 forms a portion of the outer diameter D2. In some embodiments, the ring 19 may be considered to have a second section 16 that is larger than the outer diameter of the first section 11. In such embodiments, the body of the valve seat may be cylindrical, with the addition ring 19 providing the second section 16 with a larger outer diameter D2. Alternatively, as illustrated in fig. 9 and 10, the second section 16, which is separate from the ring 19, may have an outer diameter D2 that is greater than the outer diameter D1 of the first section.

Shoulder 17 is formed by the larger outer diameter D2 of second section 16. In the embodiment of fig. 9, the shoulder surface 17a is substantially perpendicular to the longitudinal axis 14 of the valve seat 10. In other embodiments, the shoulder surface 17a may taper and/or form an angle with the longitudinal axis having a value of 5 to 70 degrees. The design of shoulder 17 may be selected based on a number of considerations, including, but not limited to, the inlet geometry of the fluid passageway and the pressure experienced by the base during operation. For example, in some embodiments, the taper of the shoulder may be provided according to the curvature of the fluid passage inlet that engages the shoulder. The first section 11 transitions to the second section 16 at a curved intersection point 18. The bend intersection can have any desired radius. In some embodiments, the radius of the curved intersection point may be 0.05 to 0.5 times the shoulder width. In other embodiments, there is no curved transition between the first section and the second section. Further, in some embodiments, the outer diameter (D2) of the second section (16) is equal or substantially equal to the outer diameter (D1) of the first section (11) (e.g., D1 — D2).

The second section 16 further comprises a frusto-conical valve mating surface 20, wherein the second section 16 is surrounded by a ring 19. In the embodiment of fig. 9, the ring 19 is connected to the outer surface of the second section 16 in a concentric arrangement. The ring 19 transfers the compressive stress condition to the second section 16. By placing the second section 16 in compressive stress, the ring 19 can help balance or equalize the stress between the first section 11 and the second section 16 when the first section 11 is press-fit into the fluid passage of the fluid end. The compressive stress condition may also prevent crack formation and/or propagation in the second segment 16, thereby enhancing the service life of the valve seat and reducing the occurrence of sudden or severe seat failures. The compressive stress condition may also enable the use of harder and more brittle materials in the second section 16, such as harder and more wear-resistant grades of cemented carbide that form the mating surfaces of the valve.

In the embodiment of fig. 9, the ring 19 forms a planar interface with the outer surface or perimeter of the second section 16. In other embodiments, the ring 19 may include one or more protrusions or flanges that reside on the inner annular surface of the ring 19. A protrusion or flange on the inner ring surface may be press fit into a recess or groove along the perimeter of the second section 16. This structural arrangement may facilitate proper engagement between the ring 19 and the second section 16. This structural arrangement may also help to retain the second section 16 within the ring 19 during operation of the fluid end. In another embodiment, the second section 16 may comprise one or more protrusions of the flange for engagement with one or more recesses in the inner annular surface of the ring 19.

FIG. 10 is a schematic illustrating another embodiment of a valve seat described herein. The valve seat of fig. 10 includes the same structural features illustrated in fig. 9. However, the ring 19 in fig. 10 at least partially covers the shoulder 17. For example, the ring 19 may be provided with a radial flange 19a for engaging the shoulder 17 of the second section 16. In some embodiments, the ring 19 completely covers the shoulder 17. FIG. 11 is a bottom plan view of a valve seat having the architecture of FIG. 10. As illustrated in fig. 11, a ring 19 is connected to the periphery of the second section and partially covers the shoulder 17. FIG. 12 is a top plan view of a valve seat having the architecture of FIG. 10. The frusto-conical valve mating surface 20 transitions into the bore 21 of the valve seat 10. The ring 19 surrounds the second section 16, thereby transferring the compressive stress condition to the second section 16. Thus, compressive stress conditions are transferred to the valve mating surface 20, which may help resist crack formation and/or crack propagation in the mating surface 20. Further, fig. 13 illustrates a perspective view of the valve seat of fig. 10. Fig. 14 illustrates a side elevational view of a valve seat according to some embodiments, wherein there is no curved intersection between the first section 11 and the second section 16.

As described herein, the valve seat may comprise sintered cemented carbide. In some embodiments, the first and second sections of the valve seat are each formed of sintered cemented carbide. Alternatively, the first segment may be formed of a metal or alloy, such as steel or a cobalt-based alloy, and the second segment is formed of a sintered cemented carbide. Forming the second section of sintered cemented carbide may impart hardness and wear resistance to the valve mating surface relative to other materials such as steel.

In some embodiments, the second section is formed from a composite material comprising a sintered cemented carbide and an alloy. For example, a sintered cemented carbide inlay may be connected to the steel substrate, wherein the sintered cemented carbide inlay forms a portion or all of the valve mating surface and the steel substrate forms the remainder of the second section. In such embodiments, the cemented carbide inlay may extend radially to contact the ring surrounding the second segment, thereby permitting the ring to transfer compressive stress conditions to the cemented carbide inlay. In other embodiments, the steel or alloy substrate includes a recess in which the cemented carbide inlay is located. In this embodiment, the outer edge of the recess is located between the cemented carbide inlay and the ring, wherein the compressive stress transmitted by the ring is transmitted to the cemented carbide inlay through the outer edge.

In some embodiments, the sintered cemented carbide inlay is provided as a single, integral piece. The sintered cemented carbide inlay may also be provided as a plurality of radial segments. Any number of radial segments is contemplated. In some embodiments, providing a sintered cemented carbide inlay as multiple radial segments may extend inlay service life by inhibiting crack propagation and/or other failure modes that may cause premature failure of an inlay having a single piece construction. For example, degradation and/or failure of one radial segment may not have any effect on the other radial segments of the inlay.

The sintered cemented carbide of the valve seat may comprise tungsten carbide (WC). WC may be present in the cemented carbide in an amount of at least 70 wt.% or in an amount of at least 80 wt.%. Additionally, the metallic binder of the cemented carbide may comprise cobalt or a cobalt alloy. For example, cobalt may be present in the sintered cemented carbide in an amount in the range of 3 to 20 wt.%. In some embodiments, the cobalt is present in the sintered cemented carbide of the valve seat in an amount of 5 to 12 wt.%, or 6 to 10 wt.%. Further, the cemented carbide valve seat may exhibit a binder-rich zone beginning at and extending inwardly from the surface of the substrate. The sintered cemented carbide of the valve seat may also include one or more additives, for example, one or more of the following elements and/or compounds thereof: titanium, niobium, vanadium, tantalum, chromium, zirconium and/or hafnium. In some embodiments, titanium, niobium, vanadium, tantalum, chromium, zirconium, and/or hafnium forms solid solution carbides with WC of the cemented carbide. In such embodiments, the cemented carbide may include one or more solid solution carbides in an amount in the range of 0.1 wt.% to 5 wt.%.

In some embodiments, a single stage of sintered cemented carbide may be used to form the first and second sections of the valve seat. In other embodiments, one or more compositional gradients may exist between the sintered cemented carbide of the first and second segments. For example, the sintered cemented carbide of the first segment may have a larger average grain size and/or a higher metal binder content to increase toughness. Conversely, the cemented carbide of the second segment may have a smaller average grain size and less binder to enhance hardness and wear resistance. In addition, a compositional gradient may exist within the first and/or second sections of the valve seat. In some embodiments, the sintered cemented carbide forming the mating surface of the valve comprises a smaller average grain size and a lower metal binder content to enhance hardness and wear resistance. Proceeding away from the valve mating surface, the sintered cemented carbide composition of the second section may increase grain size and/or binder content to enhance toughness and fracture resistance. In some embodiments, for example, the high hardness and high wear resistance sintered cemented carbide may extend to a depth of 50 μm to 1mm or 75 μm to 500 μm in the second section. Once the desired depth is reached, the sintered cemented carbide composition becomes a more ductile fracture-resistant composition.

In some embodiments, when the valve mating surface is formed of a sintered cemented carbide, the sintered cemented carbide may have a surface roughness (R) of 1 μm to 15 μm_a). Surface roughness (R) of sintered cemented carbide_a) It may be 5 μm to 10 μm. The surface roughness of the sintered cemented carbide forming the valve mating surface may be obtained via mechanical operations including, but not limited to, grinding and/or grit blasting techniques. Further, the sintered cemented carbide forming the second section of the valve comprising the valve mating surface may exhibit a compressive stress condition of at least 500 MPa. In some embodiments, the sintered cemented carbide forming the second section may have a compressive stress condition selected from table I.

TABLE VI sintered cemented carbide compressive stress (GPa)

≥1
	≥1.5
≥2
	0.5-3
1-2.5

The compressive stress condition of the sintered cemented carbide may result from compression transmitted by surrounding the second section with a ring and/or mechanically manipulating the sintered cemented carbide to provide a valve mating surface having a desired surface roughness. Can be based on Sin²The psi method determines the compressive stress of the sintered cemented carbide via X-ray diffraction. The sintered cemented carbide of the valve seat may also exhibit a hardness of 88 to 94 HRA.

The ring surrounding the second section may be formed of any suitable material that can be used to transfer a compressive stress condition to the second section. In some embodiments, the ring is formed from a metal or alloy, such as steel. The ring may also be formed of ceramic, cermet, and/or a polymeric material such as polyurethane.

In another aspect, a valve seat includes a first section for insertion into a fluid passage of a fluid end, and a second section extending longitudinally from the first section, the second section including a frustoconical valve mating surface including a surface roughness (R) having a thickness of 1 μm to 15 μm_a) The sintered cemented carbide of (1). In some embodiments, the sintered cemented carbide of the valve mating surface is provided as an insert ring connected to the metal or alloy body. In other embodiments, the second section is formed of sintered cemented carbide. The outer diameter of the second section may be greater than the outer diameter of the first section. Alternatively, the outer diameters of the first and second sections are the same or substantially the same. Further, the second section of the valve seat may optionally be surrounded by a ring as described herein.

In another aspect, a valve seat for a fluid end includes a body including a first section for insertion into a fluid passage of the fluid end and a second section extending longitudinally from the first section. The second section includes a recess in which a sintered cemented carbide inlay is located, wherein the sintered cemented carbide inlay includes a valve mating surface and exhibits a compressive stress condition. In some embodiments, the sintered cemented carbide inlay has a surface roughness (R) of 1 μm to 15 μm_a). FIG. 15 illustrates a sintered cemented carbide inlay according to some embodiments. The sintered cemented carbide inlay 70 includes a frustoconical valve mating surface 71. The sintered cemented carbide forming the inlay 70 may have any of the compositions and/or properties described above. The sintered cemented carbide inlay may be connected to a metal or alloy body or sleeve. The metal or alloy body may form a portion of the first section and the second section of the valve seat. FIG. 16 is a cross-sectional view of a valve seat including a sintered cemented carbide inlay connected to an alloy body or sleeve according to some embodiments. In the embodiment of FIG. 16, the alloy body 82 forms a first section 81 of the valve seat 80 for insertion intoIn the fluid channel of the fluid end. The alloy body 82 also forms a portion of the second section 86 and defines a recess 83 in which the sintered cemented carbide inlay 70 is located. As in FIG. 15, the sintered cemented carbide inlay 70 includes a surface roughness (R) having a range of 1 μm to 15 μm_a) The frusto-conical valve mating surface 71. In some embodiments, R of the valve mating surface 71_aIs 5 μm to 10 μm. The sintered cemented carbide inlay 70 may be attached to the alloy body 82 by any desired means including brazing, sintering, heat staking and/or press fitting. In some embodiments, the inner annular surface of the alloy body in the second section 86 includes one or more protrusions for engaging with a groove on the periphery of the sintered cemented carbide inlay 70. In some embodiments, the alloy body 82 may transfer a compressive stress condition to the sintered cemented carbide inlay 70. For example, the second section 86 of the alloy body 82 may transfer a compressive stress condition to the sintered cemented carbide inlay 70. In some embodiments, the sintered cemented carbide inlay 70 may exhibit a compressive stress having a value selected from table I above. The alloy body 82 may be formed from any desired alloy, including but not limited to steel and cobalt-based alloys. In the embodiment of FIG. 16, alloy body 82 provides a portion of second section 86 having an outer diameter D2 that is greater than outer diameter D1 of first section 81. In some embodiments, outer diameter D1 may vary with the taper of outer surface 84 of first section 81. A curved intersection 88 exists at the transition of the first section 81 and the second section 86. In addition, the larger outer diameter D2 of second section 86 forms shoulder 87. The shoulder 87 may have a structure as described in fig. 9-10 herein. In other embodiments, the outer diameter D1 of the first section 81 and the outer diameter D2 of the second section 86 are the same or substantially the same. In such embodiments where D1 is equal to D2, the outer surface 84 of the body 82 may be cylindrical.

As described herein, the first and second sections of the valve seat may have the same outer diameter or substantially the same outer diameter. In such embodiments, the valve seat exhibits a single outer diameter as compared to the dual outer diameters (D1, D2) of the valve seat illustrated in fig. 16. FIG. 17 illustrates a single outer diameter valve seat including a sintered cemented carbide inlay according to some embodiments. The reference numerals in fig. 17 correspond to the same components as in fig. 16. As illustrated in fig. 17, the valve seat 80 includes a single outer diameter D1. In some embodiments, the valve seat 80 does not employ an inlay 70 of sintered cemented carbide or other wear resistant material. For example, the valve mating surface may be formed of the same alloy as the remainder of the seat body. In some embodiments, a wear-resistant cladding may be applied to the alloy of the valve mating surface. The wear resistant cladding may comprise a cobalt-based or nickel-based alloy, or a metal matrix composite, as described herein. In further embodiments, the outer diameter of the valve seat may taper in a direction away from the valve mating surface. For example, the first section of the base may have a larger outer diameter than the second section. However, there is no shoulder between the first and second sections, and the outer diameter tapers linearly inward. The wear insert or cladding may also be used in embodiments where the outer diameter of the valve seat is tapered without establishing a shoulder.

III.Fluid flow control

In another aspect, methods of controlling fluid flow are also described herein. In some embodiments, a method of controlling fluid flow includes providing a valve assembly including a valve seat and a valve in reciprocating contact with the valve seat. The valve includes a head portion including a circumferential surface and a valve seat mating surface. Leg members extend from the head, wherein a thickness of one or more of the leg members tapers in a direction away from the head. The valve is out of contact with the valve seat to enable fluid flow through the assembly, wherein the one or more tapered leg members cause laminar fluid flow around the head. The valve then cooperates with the valve seat to prevent fluid flow through the valve. In some embodiments, the seal is attached to a circumferential surface of the head. The seal may have a radius of curvature that maintains laminar fluid flow around the valve. The valve and valve seat of the assembly may have any of the architectures, compositions, and/or characteristics described in sections I and II above. For example, the valve and valve seat may exhibit the architecture and functionality as described in fig. 1-17 herein.

Various embodiments of the present invention have been described to achieve various objects of the present invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Many modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the present invention.

Claims

1. A valve, comprising:

a head comprising a circumferential surface and a valve seat mating surface, the valve seat mating surface comprising a sintered cemented carbide; and

leg members extending from the head, wherein a thickness of one or more of the leg members tapers in a direction away from the head to create a laminar fluid flow around the head.

2. The valve of claim 1, wherein the cemented carbide is an inlay connected to the head.

3. The valve of claim 2, wherein the inlay is a single piece of sintered cemented carbide.

4. The valve of claim 2, wherein the inlay includes a plurality of individual radial segments.

5. The valve of claim 2, wherein the inlay is brazed to a surface of the head.

6. The valve of claim 2, wherein the inlay is mechanically connected to the head.

7. The valve of claim 2, wherein the inlay is attached to a substrate and the substrate is connected to the head.

8. The valve of claim 7, wherein the substrate is connected to the head by at least one of welding, mechanical locking, and adhesive.

9. The valve of claim 2, wherein the head includes an annular groove in which the inlay is located.

10. The valve of claim 1, wherein an intermediate body member is located between the head and leg members.

11. The valve of claim 1, wherein a transition between the intermediate body member and the head has a radius of curvature of 0.5mm to 5 mm.

12. The valve of claim 1, further comprising a seal coupled to the circumferential surface of the head.

13. The valve of claim 12, wherein an outer surface of the seal exhibits a radius of curvature that maintains the laminar fluid flow around the valve.

14. The valve of claim 12, wherein the seal forms an angle with the valve seat mating surface in the range of 5 degrees to 30 degrees.

15. The valve of claim 1, wherein one or more of the legs have a taper angle of 1 to 10 degrees.

16. A valve, comprising:

a seal coupled to the circumferential surface, wherein the seal is angled with respect to the valve seat mating surface to establish a primary seat contact area on the seal proximate an outer circumferential surface of the seal.

17. The valve of claim 16, wherein the angle is in the range of 5 to 30 degrees.

18. The valve of claim 16, wherein the cemented carbide is an inlay connected to the head.

19. The valve of claim 18, wherein the inlay is a single piece of sintered cemented carbide.

20. The valve of claim 18, wherein the inlay includes a plurality of individual radial segments.