Patent Application
20160238156
This disclosure relates generally to fluid delivery systems and more particularly to valve assemblies delivering particulate-containing fluids.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
It is common to pump fluids that contain particulates into oil and gas wells. For example, fracturing fluids typically contain proppant particles, such as sand, synthetic particles or small beads, with sizes typically from U.S. Standard Sieve sizes 10 through 60. Reciprocating plunger pumps are frequently used to create the high-pressure fluid flow needed to inject fluids, such as fracturing fluids, into oil and gas formations. These pumps typically include valve assemblies that are biased toward the closed position. When the motion of the plunger creates a differential pressure across the valve, the differential pressure forces the valve open, allowing the fluid to flow through the valve. However, solid particles in the fluid can become trapped within the valve assembly upon valve body, allowing extrusion or damage to valve assembly components and reducing the useful life of the valve assembly.
Valves used for slurry service typically have a resilient sealing insert around the outer perimeter of the valve body member to provide effective valve sealing. Pressure applied to a closed valve forces the resilient sealing insert to become a hydraulic seal and a portion of the insert is extruded into the gap between the valve body member and the valve seat member. For the insert to affect a hydraulic seal upon valve closure, the insert must protrude from the valve body member toward the valve seat member when the valve is open. The amount of protrusion of the insert is called the insert standoff. When the valve is nearly closed, the resilient sealing insert contacts the valve seat member before the contact surfaces of the valve body member and the valve seat member make contact. When the valve is closed, the resilient sealing insert is deformed against the seat member to form the hydraulic seal, and metal-to-metal contact occurs between the valve body member and the valve seat member in the strike face area. The insert material does not compress, but rather deforms. Repeated deformation of the insert material causes internal heat build-up and material stress within the insert material, and this can damage it. Combined with repeated deformation and presence of hard particles, such as sand or other proppant materials, extrusion and cyclic fatigue of the insert material can occur, and potential lead to further valve or pump damage and/or failure.
Also, conventional liquid end valve assemblies may also experience failures due to foreign objects becoming lodged within the valve assembly (e.g., bolts or gravel can accidentally enter the fluid flow path). These foreign objects can become wedged between the contact surfaces of the valve, and thus prevent the valve from closing, and damaging the sealing inserts. In an operational setting, continual inspection and maintenance efforts are made to detect damage to, and erosion of, the sealing inserts. However, making a decision to replace valves due to sealing insert damage and erosion can often be a subjective or difficult evaluation. This can often lead to unnecessary replacement and use of resources, or even damage to valves and/or pumps.
There is a need for improved valve assemblies which improve or overcome difficulties in assessing damage to, and erosion of, the sealing inserts, and such need is addressed, at least in part, by embodiments described in the following disclosure.
This section provides a general summary of the disclosure, and is not a necessarily a comprehensive disclosure of its full scope or all of its features.
In a first aspect of the disclosure, a valve element includes a valve body member formed of a rigid material, where the valve body member defines a front-to-rear extending longitudinal axis, and has a generally radially outwardly facing first contact surface of generally frusto-conical configuration tapering forwardly, and a radially inwardly extending annular recess disposed rearwardly of the contact surface. The valve body member further has a sealing insert mounted on the valve body member which includes a generally radially inwardly projecting lip received in the recess, an axially forwardly facing sealing face, a radially inwardly facing second contact surface disposed between the sealing face and the lip which tightly engages the first contact surface to conform to the frusto-conical configuration thereof, and a seal abrasion gauge disposed upon an outer peripheral portion of the axially forwardly facing sealing face. In some aspects, the seal abrasion gauge may be integrated with or otherwise disposed within the sealing insert. In some other aspects, the seal abrasion gauge is an insert disposed adjacent an outer peripheral portion of the axially forwardly facing sealing face and a radially outwardly facing third contact surface disposed upon an opposing side of the sealing insert relative the second contact surface. In some embodiments, the seal abrasion gauge has a color in contrast with a color of the sealing insert, and may be formed from a colorant infusion in the sealing insert.
In another embodiment of the disclosure, a valve element is provided which includes a valve body member formed of a rigid material, where the valve body member defines a front-to-rear extending longitudinal axis. The valve body member also has a generally radially outwardly facing first contact surface of generally frusto-conical configuration tapering forwardly, and a radially inwardly extending annular recess disposed rearwardly of the contact surface. The valve body member further has a sealing insert mounted on the valve body member which includes a generally radially inwardly projecting lip received in the recess, an axially forwardly facing sealing face, a radially inwardly facing second contact surface disposed between the sealing face and the lip which tightly engages the first contact surface to conform to the frusto-conical configuration thereof, and a seal abrasion gauge integrated with an outer peripheral portion of the axially forwardly facing sealing face. In some cases, the seal abrasion gauge is an insert disposed adjacent an outer peripheral portion of the axially forwardly facing sealing face and a radially outwardly facing third contact surface disposed upon an opposing side of the sealing insert relative the second contact surface, while in other cases the seal abrasion gauge is integrated with the sealing insert. The seal abrasion gauge may have a color in contrast with a color of the sealing insert.
Yet another aspect of the disclosure is a valve element having a valve body member formed of a rigid material, and the valve body member defines a front-to-rear extending longitudinal axis. The valve body member also has a generally radially outwardly facing first contact surface of generally frusto-conical configuration tapering forwardly, and a radially inwardly extending annular recess disposed rearwardly of the contact surface. The valve body member further includes a sealing insert mounted on the valve body member which includes a generally radially inwardly projecting lip received in the recess, an axially forwardly facing sealing face, a radially inwardly facing second contact surface disposed between the sealing face and the lip which tightly engages the first contact surface to conform to the frusto-conical configuration thereof, and a radially outwardly facing third contact surface disposed upon an opposing side of the sealing insert relative the second contact surface. A seal abrasion gauge is disposed adjacent the third contact surface.
Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described and are not meant to limit the scope of various technologies described herein, and:
The following description of the variations is merely illustrative in nature and is in no way intended to limit the scope of the disclosure, its application, or uses. The description and examples are presented herein solely for the purpose of illustrating the various embodiments of the disclosure and should not be construed as a limitation to the scope and applicability of the disclosure.
Unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by anyone of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
In addition, use of the “a” or “an” are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of concepts according to the disclosure. This description should be read to include one or at least one and the singular also includes the plural unless otherwise stated.
The terminology and phraseology used herein is for descriptive purposes and should not be construed as limiting in scope. Language such as “including,” “comprising,” “having,” “containing,” or “involving,” and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited.
Also, as used herein any references to “one embodiment” or “an embodiment” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily referring to the same embodiment.
Referring to
In operation, the discharge stroke of the plunger 140 results in an elevated pressure within the compression chamber 105. The elevated pressure within the compression chamber 105 causes the valve body member 130 of discharge valve 100 to move away from the valve seat member 120 as shown by the arrow 146. This allows fluid to be displaced from the compression chamber 105, through the valve seat member bore 122, and into the discharge chamber 106. Fluid flow from the compression chamber 105 into the discharge chamber 106 is referred to as forward flow through the valve apparatus 100. When valve body member 130 of discharge valve 100 is raised by fluid forces arising from the forward motion of the plunger 140, the compression spring 134 is compressed and exerts an increasing force downward on the valve body member 130. When the plunger 140 slows towards the end of its discharge stroke, the fluid forces upward on the valve body member 130 decrease and become less than the spring force downward on the valve body member 130. The valve body member 130 is pushed downwards towards its closed position against the valve seat member 120. The compression spring 134 moves the valve body member 130 towards the valve seat member 120 to reestablish the contacting relationship between frusto-conical contact surface 124 and frusto-conical contact surface 132. Further movement of the plunger 140 in a suction stroke will create a suction within the intake chamber 104 and the suction valve assembly 100a will work in a similar manner, allowing fluid to be drawn into the intake chamber 104 and compression chamber 105. At the start of the plunger 140 suction stroke, a small amount of fluid flows from the discharge chamber 106 into the suction chamber 104. This is referred to as reverse flow through the valve apparatus 100. This reverse flow will continue until the combined forces of the suction pressure within the intake chamber 104 and the compression spring 134 are sufficient to form a positive seal between the valve body member 130 and the valve seat member 120 of suction valve assembly 100a.
Forward flow and reverse flow through the valve apparatus 100 have separate working mechanisms and are not equivalent. Forward flow results when the pressure in the intake chamber 104 is sufficiently greater than the pressure in the discharge chamber 106 that it overcomes the resistance force applied by the compression springs 134. Forward flow involves hydrostatic pressure overcoming a resisting force. Reverse flow also needs a pressure differential across the valve assembly 100a. But rather than the pressure differential overcoming an opposing force, reverse flow involves the time lag inherent in the valve body member 130 of valve assembly 100a closing. Once the pressure has equalized between the intake chamber 104 and the discharge chamber 106, the forward flow of fluid will stop. At that time the valve body member 130 of valve assembly 100a will still be in the process of approaching the valve seat member 120, moving in response to the force from the compression spring 134. The time period between the cessation of the forward fluid flow and the closing of the valve body member 130 upon the valve seat member 120 is commonly referred to as valve lag. During this valve lag time period the start of the plunger suction stroke has reduced the pressure within the intake chamber 104 to less than the discharge chamber 106. This results in a reverse fluid flow until there is an adequate fluid seal between the valve body member 130 of valve assembly 100a and the valve seat member 120. If an adequate fluid seal between the valve body member 130 and the valve seat member 120 is not achieved, there will be reverse fluid flow throughout the entire suction stroke, and pumping efficiency may be significantly diminished.
A sealing insert 136 is attached to the valve body members 130 at the outer perimeter that acts to help effectuate a seal between frusto-conical contact surface 124 and frusto-conical contact surface 132. The distance between the sealing insert 136 and the opposing frusto-conical contact surface creates a valve exit gap 138. The sealing insert also acts to dampen the stress forces imposed on the valve seat member 120 and the valve body member 130 upon valve closure. For the sealing insert 136 to be effective, the valve exit gap 138 between the sealing insert 136 and the valve seat contact surface 124 must be smaller than the gap between the valve body member contact surface 132 and the valve seat contact surface 124, when the valve is open.
A common problem often occurs within pump assemblies that are used to pump solid laden fluids or slurries, such as hydraulic fracturing fluid containing proppant particles. As the valve body member 130 approaches the valve seat member 120, the resilient insert 136 approaches the opposing frusto-conical contact surface 124 and the valve exit gap 138 decreases. When the valve exit gap 138 reaches a certain point (for example, about 1.0-2.5 times the average solid particle diameter), the valve exit gap 138 will act to screen out the solid particles while still allowing fluid flow to pass. This forward screening effect will result in an accumulation of solid particles 144 (sixteen shown) between the valve seat member 120 and the valve body member 130. As the valve body member 130 closes against the valve seat member 120, the accumulation of solid particles 144 imposes localized forces onto the valve assembly. These localized forces can result in damage to the valve seat member 120, the valve body member 130 or the resilient insert 136, such as pitting or erosion on one or more of the frusto-conical contacting surfaces or resilient insert. Hence, in an operational setting, continual inspection and maintenance efforts are thus required to detect damage to, deformation of, and erosion of, the resilient sealing inserts 136. In some cases where sealing inserts 136 significantly erode or fail, crushing of individual particles may result in Hertzian contact stresses and damage to the frusto-conical contact surfaces 124 and/or 132.
Now referring to
Sealing insert 336 further includes a peripheral contact surface 366, and axially forwardly facing sealing face 376. In some aspects of the disclosure, sealing insert 336, or any sealing insert according to the disclosure, is formed of a material and/or contains additives with anti-extrusion properties to reduce or even prevent sealing insert material extrusion into the gap, such as exit gap 138 shown in
Now referencing
Another embodiment of a valve element in accordance with the disclosure is shown in
The components of the valve elements in accordance with the disclosure may be made from a variety of materials depending on design factors such as the type of fluid to be pumped and the pressure rating that is needed. For example, the pump body portion 102 and the valve seat member 120, shown in
Materials used to form seal abrasion gauge according to the disclosure may in some cases be like materials as those used to form the sealing inserts, and in some other instances, materials different from those used to form the sealing inserts. When different materials are used, they are generally more abrasion or wear resistant than the sealing insert material. Such material may be selected based upon properties of abrasion resistance and capability for surviving large repeated deformations, and may include materials such as polyurethane, polyamide, polyacetal, polytetrafluorethylene, epoxies, polyimide, polycarbonate, polyethylene, polypropylene, polydimethylsiloxane, or any suitable thermoset or thermoplastic polymers, combinations thereof, and the like. In some aspects, the material may be further amended with other components to achieve targeted properties, such as aramid fiber, carbon fiber, graphite powder, glass fiber, molybdenum disulfide particles, and the like.
The foregoing description of the embodiments has been provided for purposes of illustration and description. Example embodiments are provided so that this disclosure will be sufficiently thorough, and will convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the disclosure, but are not intended to be exhaustive or to limit the disclosure. It will be appreciated that it is within the scope of the disclosure that individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
Also, in some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. Further, it will be readily apparent to those of skill in the art that in the design, manufacture, and operation of apparatus to achieve that described in the disclosure, variations in apparatus design, construction, condition, erosion of components, gaps between components may present, for example.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.
