VALVE SEAT WITH CERAMIC INSERT

Abstract

A valve seat for a valve assembly for a high-pressure fluid pump is described. The valve assembly includes a valve body and a valve seat made of a first material. The valve seat has a generally tubular body with an annular collar whose outer diameter extends beyond the outer diameter surface of the tubular body, and an annular insert made of a second, more durable material than the first material. This insert is fitted to form an inner diameter surface of the collar, creating an annular sealing surface against which the valve body rests when in the closed position. The insert forms a projecting annular edge on its inner diameter surface, offset from the inner diameter surface of the tubular body to form a chamfered annular edge.

Description

VALVE SEAT WITH CERAMIC INSERT FIELD OF INVENTION This description refers to valves for high-pressure fluid applications, and more particularly to a valve seat with a ceramic insert for a reciprocating pump. BACKGROUND OF THE INVENTION Hydraulic fracturing (also known as fracking) is a process for extracting hydrocarbons such as natural gas and oil by injecting a fracturing fluid or mud at high pressure into a well to create fractures in deep rock formations. The hydraulic fracturing process employs various types of equipment at the well site, including one or more positive displacement pumps, a mud mixer, fracturing fluid tanks, a high-pressure flow iron (pipe or conduit), a wellhead, valves, loader pumps, and trailers on which some of the equipment is transported. Positive displacement pumps are commonly used in oil fields for high-pressure hydrocarbon recovery applications, such as injecting fracturing fluid into the well. A positive displacement pump may include one or more plungers. MA / a / ZUZZ / U 1 I zoo Ref. 338484, driven by a crankshaft to create high or low pressure in a fluid chamber. A positive displacement pump typically has two sections: a power end and a fluid end. The power end includes a crankshaft driven by a motor that drives the plungers. The fluid end of the pump includes cylinders in which the plungers operate to draw fluid into the fluid chamber and then push it at high pressure into a discharge manifold, which is in fluid communication with a wellhead. BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a cross-sectional view of one modality of a linear pump with a ceramic insert according to the teachings of the present description; Figure 2 is a close partial view of one modality of a linear pump with a ceramic insert according to the teachings of the present description; Figure 3 is a perspective view of an exemplary modality of a valve body according to the teachings of the present description; Figure 4 is a cross-sectional view of one embodiment of a valve assembly according to the teachings of the present description; and Figure 5 is a perspective view of an exemplary modality of a fracturing pump according to the teachings of the present description. I too DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows a cross-sectional view of a valve seat 10 for a fluid inlet valve assembly 40 and / or a fluid outlet valve assembly 40 of a reciprocating pump 50 (Figure 5). The inlet valve assembly 40 is arranged in a fluid inlet passage, and the outlet valve assembly is arranged in the fluid outlet passage at the fluid end 54 of the pump 50. The valve assemblies 40 may incorporate a spring 42 so that they are spring-loaded. The valve seat 10 described herein is applicable to both the inlet and outlet valve assemblies, which will hereinafter be referred to interchangeably as the valve assembly. The valve assembly 40 includes a valve seat 10 (Figures 1 and 2) and a valve body 30 (an example of which is shown in Figure 3) that engage therewith. The valve body 30, when in its closed position, seats and fits into the circular opening defined by the valve seat 10. When in its open position, the valve body 30 lifts and separates from the opening defined by the valve seat 10. The valve seat 10 includes a generally tubular body 12 having an inner diameter surface and an opposing outer diameter surface. The inner diameter surface of the valve seat 10 forms a cylindrical bore along a central axis of the valve seat 10, which is coaxial with the fluid flow axis when the valve assembly 40 is arranged in the fluid inlet / outlet passage.The outer diameter surface of the valve seat body 12 contacts and engages with an inner surface of the fluid passage. In one exemplary embodiment, the outer diameter surface of the valve seat forms an interference fit with the wall of the fluid passage. A sealing element 14, such as an O-ring, is arranged in an annular groove 15 formed on the outer diameter surface of the valve body 12 to seal the inner surface of the fluid inlet passage. The valve seat body 12 forms an interference fit or is press-fitted against the inner surface of the fluid cylinder, so that the valve seat 10 is securely positioned within the fluid inlet passage. In certain embodiments, at least a portion of the valve seat 10 and the valve body 30 is made of a metal such as carbon steel or stainless steel. The valve seat 10 further includes a collar 16 with an insert 17 having a tapered or curved shoulder 18 extending upward and radially from the tubular body 12. At a horizontally oriented interface on the inner diameter surface between the collar 16 and the insert 17, there is a chamfered edge 19, so that the insert 17 is slightly recessed from the inner diameter surface of the insert body 12, as best seen in Figure 2. This chamfered edge 19 can be formed, for example, by machining. In contrast, the conventional insert has an inner diameter surface that is flush with the inner diameter surface of the valve seat body. In this embodiment, shown in Figures 1 and 2, the back face of the insert 10 has an angled face 20, giving the back face of the insert two angles 24 and 25, both greater than 90 degrees.The outer surface of the collar 16 and the tubular body of the valve seat 12 contact and bear against the inner surface of the fluid inlet passage. The collar 16 further includes an annular groove 21 that is slightly recessed into the outer surface of the tubular body of the valve seat 12. The curved shoulder 18 of the collar 16 extends at an angle from the tubular body of the valve seat 12. The collar 16 has a larger outside diameter than the outside diameter of the tubular body of the valve seat 12. The valve seat insert 17 is attached to an upper inner surface of the valve seat collar 16 by press fit, shrink fit, bonding, sintering, welding, or combinations thereof. The insert 17 has a curved shoulder 18 that flares outward radially and an annular projection of inside diameter 22 that is disposed above the chamfered edge 19. In one exemplary, non-limiting embodiment, the insert 17 is made of a ceramic material, which may include zirconia, partially stabilized zirconia, a tungsten carbide such as tungsten nickel carbide or tungsten cobalt carbide, titanium carbide, silicon nitride, or sialon. The hardness of the ceramic material may range from approximately 12 to 22 GPa with reference to the Vickers hardness number. In certain embodiments, the entire valve seat 10 and valve body 30 may be formed of ceramic material, or only a portion of one or both of the valve seat and valve body may be formed of ceramic material. Generally, it is desirable to use a ceramic insert material that is harder than the valve seat body material.The use of an insert 17 thus extends the service life of the valve assembly 40, which is usually subject to corrosion, erosion, or pitting during pump operation. Figure 5 is a perspective view of an exemplary positive displacement pump 50 in which the embodiments of the novel valve seat configuration described herein can be deployed. A positive displacement pump, also known as a fracturing pump, is typically driven by high-power diesel or turbine engines (not shown). The engine's revolutions per minute (RPM) are usually reduced by means of a transmission. The transmission is usually multidirectional, so that higher pumping loads use a lower gear and lighter loads use a higher gear. The fracturing pump 50 comprises two main components: a power end 52 and a fluid end 54, which are held together by a tie rod assembly 56 that includes a plurality of tie rods and tubes.The power end 52 includes a crankshaft (not explicitly shown) driven by the engine (not explicitly shown) that drives a plurality of plungers (not explicitly shown). The fluid end 54 of the pump includes cylinders (not explicitly shown) in which the plungers operate to draw fluid from a suction manifold 58 into the fluid chamber and then push it at high pressure into a discharge manifold 59. The discharged fluid is then injected at high pressure into a cased borehole. The injected fracturing fluid is also commonly referred to as mud, which is a mixture of water, proppants (silica sand or ceramic), and chemical additives. The fracturing pump increases the pressure within the fluid cylinder by rotating the plunger longitudinally within the head cylinder. MA / a / ZUZZ / UI 1 fluid end. The power end 52 further includes a pinion gear, main gears, rod caps, bearing housing, connecting rods, crossheads, and short rods that work together to reciprocate the plunger. Due to the extreme conditions under which a fracturing pump operates, some of which have been discussed above, there is considerable wear on the various component parts, including the valve seats and valve bodies at the fluid end 54. This wear necessitates constant maintenance and, ultimately, the replacement of worn parts. Maintenance and repairs result in machine downtime and increase the overall cost of oil and gas production. The novel valve seat configuration described herein can be used for any valve and seal present in the fracturing pump, as well as for other types of equipment that may be present at a typical hydraulic fracturing site. A typical hydraulic fracturing site employs positive displacement pumps, a mud mixer, fracturing fluid tanks, high-pressure flow iron (pipe or conduit), trailers on which some equipment is transported, valves, a wellhead, a feed pump (typically a centrifugal pump), conveyors, and other equipment at the site of a hydraulic fracturing operation or other types of hydrocarbon recovery operations. The novel features of the present invention are set forth below, particularly in the appended claims. However, the modifications, variations, and changes to the exemplary embodiments described above will be evident to those skilled in the art, and the described ceramic insert valve seat encompasses such modifications, variations, and changes and is not limited to the specific embodiments described herein. It is hereby stated that, as of this date, the best method known to the applicant for putting the aforementioned invention into practice is the one that is clear from the present description of the invention.

Claims

CLAIMS Having described the invention as above, the following claims are claimed as property:

1. A valve assembly for a high-pressure fluid pump, characterized in that it comprises: a valve body; and a valve seat made of a first material and including: a tubular body having an inner diameter surface and an outer diameter surface; an annular sealing member disposed within an annular groove formed in the outer diameter surface of the tubular body; the tubular body having an annular collar whose outer diameter surface extends beyond the outer diameter surface of the tubular body;and an annular insert made of a second material more durable than the first material and fixed to form an inside diameter surface of the collar, the insert forming an annular sealing surface against which the valve body rests when in a closed position, the insert further forming an annular projection edge on its inside diameter surface which is offset from the inside diameter surface of the tubular body to form an annular beveled edge, and the insert having a back face formed by sides that intersect at angles greater than 90 degrees.

2. The valve assembly according to claim 1, characterized in that the first material is selected from the group consisting of carbon steel and stainless steel and the second material comprises a ceramic material.

3. The valve assembly according to claim 1, characterized in that the tubular body further defines an annular groove on the surface of the outer diameter arranged below the collar.

4. The valve assembly according to claim 1, characterized in that it further comprises a polarizing member.

5. The valve assembly according to claim 1, characterized in that the insert is fixed to the valve seat by a method selected from the group consisting of press fit, shrink fit, bonding, sintering, and welding.

6. A valve seat for a valve of a high-pressure fluid pump, characterized in that it comprises: a tubular body made of a first material and having an inner diameter surface and an outer diameter surface; the tubular body having an annular collar whose outer diameter surface extends beyond the outer diameter surface of the tubular body; and an annular insert made of a second material more durable than the first material and fixed to form an inner diameter surface of the collar, the insert forming an annular sealing surface against which the valve body rests when in a closed position, the insert further forming an annular projection edge on its inner diameter surface which is offset from the inner diameter surface of the tubular body to form an annular chamfered edge.

7. The valve seat according to claim 6, characterized in that the insert has a back face formed by sides that intersect at angles greater than 90 degrees.

8. The valve seat according to claim 6, characterized in that the first material is selected from the group consisting of carbon steel and stainless steel.

9. The valve seat according to claim 6, characterized in that the second material comprises a ceramic material.

10. The valve seat according to claim 6, characterized in that the tubular body further defines an annular groove on the surface of the outer diameter disposed below the collar.

11. The valve seat according to claim 6, characterized in that it further comprises an annular sealing member disposed within an annular groove formed on the surface of the outer diameter of the tubular body to seal with a fluid passage that receives the valve seat.

12. A valve assembly for a high-pressure fluid pump, characterized in that it comprises: a valve body; and a valve seat made of a first material and including: a tubular body having an inner diameter surface and an outer diameter surface; the tubular body having an annular collar whose outer diameter surface extends beyond the outer diameter surface of the tubular body; and an annular insert made of a second material more durable than the first material and fixed to form an inner diameter surface of the collar and forming an annular sealing surface against which the valve body abuts when in the closed position.

13. The valve assembly according to claim 12, characterized in that the insert further forms MA / a / SUSS / Ul 1 an annular protruding edge on its inner diameter surface which is offset from the inner diameter surface of the tubular body to form a beveled annular edge.

14. The valve assembly according to claim 12, characterized in that the annular insert has a back face formed by sides that intersect at angles greater than 90 degrees.

15. The valve assembly according to claim 12, characterized in that it further comprises an annular sealing member disposed within an annular groove formed on the surface of the outer diameter of the tubular body.

16. The valve assembly according to claim 12, characterized in that the first material is selected from the group consisting of carbon steel and stainless steel and the second material comprises a ceramic material 17. The valve assembly according to claim 12, characterized in that the tubular body further defines an annular groove on the surface of the outer diameter disposed below the collar.

18. The valve assembly according to claim 12, characterized in that it further comprises a polarizing member.

19. The valve assembly according to claim 12, characterized in that the insert is fixed to the valve seat by a method selected from the group consisting of press fit, shrink fit, bonding, sintering, and welding.

Images