FIELD

The present disclosure relates to valves for high pressure fluid applications, and more particularly, to a cylindrical valve with flow port apertures for a fracking pump.

BACKGROUND

Hydraulic fracturing (a.k.a. fracking) is a process to obtain hydrocarbons such as natural gas and petroleum by injecting a fracking fluid or slurry at high pressure into a wellbore to create cracks in deep rock formations. The hydraulic fracturing process employs a variety of different types of equipment at the site of the well, including one or more positive displacement pumps, slurry blender, fracturing fluid tanks, high-pressure flow iron (pipe or conduit), wellhead, valves, charge pumps, and trailers upon which some equipment are carried.

Positive displacement pumps are commonly used in oil fields for high pressure hydrocarbon recovery applications, such as injecting the fracking fluid down the wellbore. A positive displacement pump may include one or more plungers driven by a crankshaft to create a 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 powered by an engine that drives the plungers. The fluid end of the pump includes cylinders into which the plungers operate to draw fluid into the fluid chamber and then forcibly push out at a high pressure to a discharge manifold, which is in fluid communication with a well head.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an exemplary embodiment of a cylindrical valve with flow port apertures according to the teachings of the present disclosure;

FIG. 2 is a cross-sectional side view of an exemplary embodiment of a cylindrical valve with flow port apertures according to the teachings of the present disclosure taken along line 2-2 in FIG. 1 ;

FIG. 3 is a perspective view of an exemplary embodiment of a cylindrical valve with flow port apertures according to the teachings of the present disclosure;

FIG. 4 is a perspective cross-sectional view of an exemplary embodiment of a cylindrical valve with flow port apertures according to the teachings of the present disclosure taken along line 4- 4 in FIG. 3;

FIG. 5 is a bottom perspective view of an exemplary embodiment of a cylindrical valve with flow port apertures according to the teachings of the present disclosure; FIG. 6 is a bottom cross-sectional perspective view of an exemplary embodiment of a cylindrical valve with flow port apertures according to the teachings of the present disclosure taken along line 6-6 in FIG. 5;

FIG. 7 is a top view of an exemplary embodiment of a cylindrical valve with flow port apertures according to the teachings of the present disclosure;

FIG. 8 is a bottom view of an exemplary embodiment of a cylindrical valve with flow port apertures according to the teachings of the present disclosure;

FIGS. 9 and 10 are side and cross-sectional views of an exemplary embodiment of a cylindrical valve with flow port apertures shown without the dampener element according to the teachings of the present disclosure;

FIGS. 11 and 12 are perspective and side views of an exemplary embodiment of a dampener element for a cylindrical valve with flow port apertures according to the teachings of the present disclosure;

FIGS. 13 and 14 are side and perspective views of an exemplary embodiment of a cylindrical valve assembly with flow port apertures according to the teachings of the present disclosure;

FIG. 15 is a cross-sectional side view of an exemplary embodiment of a cylindrical valve assembly with flow port apertures according to the teachings of the present disclosure;

FIGS. 16 and 17 are perspective views of an exemplary embodiment of a valve seat for a cylindrical valve with flow port apertures according to the teachings of the present disclosure;

FIG. 18 is a depiction of fluid flow out through the flow port apertures when the valve is in an open configuration according to the teachings of the present disclosure;

FIG. 19 is an exemplary graph of fluid flow rate as a function of valve opening position according to the teachings of the present disclosure;

FIG. 20 is a perspective view of an exemplary embodiment of a frack pump according to the teachings of the present disclosure.

DETAILED DESCRIPTION

FIGS. 1, 3, and 5 are side and perspective views of an exemplary embodiment of a cylindrical valve 10 with a plurality of flow port apertures 12, and FIGS. 2, 4, and 6 are cross-sectional views of the cylindrical valve 10 according to the teachings of the present disclosure. The cylindrical valve 10 has a generally cylindrical body 14 that may be thought of as having a top or head portion 15 and a bottom portion 16. The top or head portion 15 of the cylindrical valve 10 generally defines a cylindrical spring seat 17 for receiving a biasing member such as a coiled spring (not shown). The top portion 15 of the valve 10 further defines a sealing surface 18 that is configured to meet a valve seat 32 (see e.g., FIGS. 13-15), described below. The sealing surface 18 extends radially upwardly and outwardly away from the centerline, C, of the valve at approximately 45-degrees, although the sealing surface may be oriented at another suitable angle. As shown in the cross-sectional view in FIG. 2, the cylindrical valve 10 is preferably constructed of a metal core 20 bonded with a dampener element 22, constructed of urethane, a polymer, or another suitable material now known or to be developed. The sealing surface 18 is formed by the combination of the metal core 20 and the dampener element 22. The metal core 20 and the dampener element 22 may be bonded by any method heretofore known or to be developed, including casting, injection molding, using an epoxy or adhesive, etc. The metal core 20 may further include a“tail” 24 that projects downwardly along the center axis, C. The tail 24 may function to direct fluid flowing within the interior passage of the valve body outwardly toward the flow port apertures 12.

The bottom portion 16 of the cylindrical valve 10 includes a cylindrical“skirt” 26 that defines an interior flow passage as well as a plurality of flow port apertures 12 arranged circumferentially near the skirt’s upper region proximate to the sealing surface 18. Although the flow port apertures 12 are illustrated herein as triangular in shape pointing upward, they may be of any shape and in any orientation, such as triangle (pointing downward), elliptical, diamond-shape, circular, rectangular, etc.

The valve skirt 26 of the cylindrical valve 10 may further include one or more optional circumferential wiper seals 28 disposed in one or more grooves 29 (see FIGS. 9 and 10) formed in the skirt 26 below the flow port apertures 12. As shown the wiper seals 28 have a plurality of circumferential ridges, but they may have other profiles. The wiper seal 28 may be affixed to the skirt 26 by any suitable method, such as friction-fit, epoxy, adhesives, and bonding. The wiper seal 28 primarily functions to prevent contaminants and abrasive elements present in the liquid from contacting the sealing surface 18. The annular wiper seals 28 also may serve to guide the valve body along a linear path with reduced friction over metal to metal contact. One or more circumferential wiper seals may be included.

FIGS. 7 and 8 are top and bottom views of an exemplary embodiment of a cylindrical valve 10 with flow port apertures according to the teachings of the present disclosure.

Referring to FIGS. 9 and 10, the cylindrical valve 10’ is shown in perspective side view and cross-sectional side view, respectively, without the wiper seal 28 and without the dampener element 22, which is shown separately in perspective view and side view in FIGS. 11 and 12, respectively. It may be seen that the head portion 15 of the cylindrical valve 10’ defines an annular groove that is configured to snugly accommodate the dampener element 22, which is bonded thereto. The lower portion of the skirt 26 of the valve 10 also defines an annular groove 29 that is configured to accommodate the annular wiper seal 28. FIGS. 13 and 14 are side and perspective views of an exemplary embodiment of a cylindrical valve assembly 30 with flow port apertures 12 according to the teachings of the present disclosure. FIG. 15A is a cross-sectional view of the cylindrical valve assembly 30, and FIG. 15B is a partial enlarged view of the wiper seal 28 interface with the valve seat 32. The cylindrical valve assembly 30 includes the cylindrical valve 10 with flow port apertures 12 and a valve seat 32, which is shown in perspective views in FIGS. 16 and 17. It may be seen that the sealing surface 18 of the cylindrical valve 10 is configured to seamlessly meet and conform with a sealing surface 19 of the valve seat 32. Not shown explicitly, the valve seat 32 may include oen or more annular seals that are accommodated within one or more annular circumferential grooves 34 defined on its outer surface.

In operation, the cylindrical valve assembly 50 may serve as suction (inlet) and/or discharge (outlet) valves in the fluid end of a positive displacement pump. The inlet valve assembly is disposed in the fluid inlet passageway and the outlet valve assembly is disposed in the fluid outlet passageway. When the cylindrical valve 10 is closed, the sealing surface 18 presses against the valve seat sealing surface 19 so that no fluid passes. When the cylindrical valve 10 is in the open configuration, as shown in FIG. 18, fluid passes along the inside passage formed by the skirt 26 of the cylindrical valve and out through the flow port apertures 12 near the top of the valve. The majority of the flow does not start until the flow port apertures 12 are exposed as the valve rises and fully opens. Therefore, the majority of the flow is redirected away from the sealing surfaces 18 and 19 of the valve and the valve seat. Notably, the fluid flow can be kept at a distance away from both the valve body sealing surface 18 and the valve seat sealing surface 19. This is possible when the flow port apertures 12 are shorter than the height by which the valve cylinder rises above the valve seat 32, and has a beneficial effect on reducing erosion of the sealing surface and the valve seat. Further, flow velocities across the sealing surfaces are greatly reduced. By keeping the high velocity flow of the abrasive fluid confined to a center section of the total valve opening, multiple benefits may be realized: reduced wear on the sealing surface and valve seat, as well as a possible reduction in undesirable Bernoulli Effect (caused by localized lower pressure due to high velocity flow when there is a small opening at the sealing surface) that may be present, which can exert a closing force on the valve, even during a time when the valve should be opened.

FIG. 19 shows an exemplary graph of fluid flow rate as a function of valve opening position for some embodiments. The horizontal axis is the valve position and the vertical axis is the fluid flow rate. As illustrated, rapid flow does not begin immediately when the valve cylinder begins rising, because the flow port apertures are not exposed. Some amount of fluid may leak through the ports and then between the valve cylinder and the wall, however, when the flow port apertures are exposed above the valve seat, the fluid flow rate can begin to rapidly increase. After the flow port apertures are fully exposed, the fluid flow rate does not significantly increase, because the flow rate is primarily restricted (by the valve) according to the sizes of the apertures. The rate of the increase, between partial and full exposure of the apertures may be a function of the shape of the apertures. There may be some optimization possible in profiling the rate of flow increase in order to reduce stress from abrupt pressure changes. This requires use of differently-shaped apertures. Apertures that are wide near the top will give more abrupt increases in flow rate when the apertures just begin to be exposed. Apertures that are narrower near the top will give less abrupt increases in flow rate when the apertures just begin to be exposed. The distance at which the upper edges of the apertures are located below the sealing surface will largely determine the delay between valve opening and rapid escalation in the fluid flow rate. Another beneficial phenomenon is observable. As the valve closes, and the apertures begin to drop below the valve seat, the upper edges of the flow port apertures act as a sort of guillotine to cut off the fluid flow. Whereas in a prior art valve, the fluid flow is laterally compressed to stop it, resulting in friction and erosion along the sealing surfaces, with the disclosed cylindrical valve, the fluid flow is sheared off. This change in operation may shift stress and wear from the valve components to the fluid.

FIG. 20 is an elevational view of an exemplary positive displacement pump 50 in which the embodiments of the novel valve configuration described here can be deployed. A positive displacement pump 50, also known as a frac pump, is typically driven by high horsepower diesel or turbine engines (not shown). The engine's revolutions-per-minute (RPM) is usually reduced through the use of a transmission. The transmission is usually multi-geared such that higher pump loads use lower gearing and lighter loads use higher gearing. The frac pump 50 comprises two major components: a power end 52 and a fluid end 54 held together by a stay rod assembly 56 that includes a plurality of stay rods and tubes. The power end 52 includes a crankshaft (not explicitly shown) powered by the engine (not explicitly shown) that drives a plurality of plungers (not explicitly shown). The fluid end 54 of the pump 50 includes cylinders (not explicitly shown) into which the plungers operate to draw fluid into the fluid chamber and then forcibly push out at a high pressure to a discharge manifold 58. The discharged liquid is then injected at high pressure into an encased wellbore. The injected fracturing fluid is also commonly called a slurry, which is a mixture of water, proppants (silica sand or ceramic), and chemical additives. The frac pump 50 increases pressure within the fluid cylinder by reciprocating the plunger longitudinally within the fluid head cylinder. The power end 52 further includes a pinion gear, bull gears, rod caps, bearing housing, connecting rods, crossheads, and pony rods that work together to reciprocate the plunger. Because of the extreme conditions under which a frac pump operates, some of which are discussed above, there is considerable wear and tear on the various component parts including the valve members in the fluid end 54. Such wear and tear require constant maintenance, and ultimately, replacement of worn parts. Maintenance and repair result in machine downtime and increase the overall cost of oil and gas production.

The novel valve configuration described herein can be employed for any valve and seal present in the frac pump, as well as other types of equipment that may be present at an exemplary hydraulic fracturing site. An exemplary hydraulic fracturing site employs positive displacement pumps, a slurry blender, fracturing fluid tanks, high-pressure flow iron (pipe or conduit), trailers upon which some equipment are carried, valves, wellhead, charge pump (typically a centrifugal pump), conveyers, and other equipment at the site of a hydraulic fracturing operation or other types of hydrocarbon recovery operations.

The features of the present invention which are believed to be novel are set forth below with particularity in the appended claims. However, modifications, variations, and changes to the exemplary embodiments described above will be apparent to those skilled in the art, and the cylindrical valve with flow port apertures described herein thus encompasses such modifications, variations, and changes and are not limited to the specific embodiments described herein.