Gate valve

Abstract

The present invention discloses a gate valve that has a first side and a second side relative to a through-hole. A circular body cavity is on the first side, and a rectangular body cavity is on the second side and a part of the first side, whereby the gate is operable to move up and down within the body cavity. Due to the rectangular body cavity, the valve seat is thinner than the gate. A skirt assembly is used that, when the gate moves to the closed position, inserts above the gate to cover the gate opening, thereby preventing debris and other contaminants from entering the body cavity. Four U-shaped seals are installed so that the gate valve is a two-way gate valve with an upstream seal having a backup downstream seal in the event of an upstream seal failure.

Description

Background Art

[0001] The present invention generally relates to valve assemblies, and more particularly to an improved gate valve assembly.

[0002] Gate valves are used in oil fields and have an internal sliding gate that controls the fluid flow through the through-hole of the gate valve. The sliding gate is flat and has an open side and a blank-sealed side. When the open side of the gate aligns with the through-hole, then fluid can flow through the gate valve. When the blank-sealed side of the gate aligns with the drilling hole, then fluid flow through the gate valve is blocked. Summary of the Invention

[0003] An object of the present invention is to provide an improved gate valve assembly.

[0004] Another object of the present invention is to provide a gate valve assembly having a body cavity that is at least partially rectangular to reduce the weight of the valve body, so that the valve seat and the gate can be thinner than in the case where the body cavity is circular, to further reduce the weight.

[0005] Yet another object of the present invention is to provide a body cavity having a circular cavity on a first side and a rectangular cavity on a second side.

[0006] Another object of the present invention is to provide a dimensionally reduced valve seat for the gate valve assembly.

[0007] Still another object of the present invention is to provide a bi-directional seal on the valve seat to assist in sealing the fluid flow in the well.

[0008] Yet another object of the present invention is to provide a skirt assembly to prevent contaminants from entering the body cavity to ensure reliable operation of the gate valve.

[0009] Yet another object of the present invention is to provide upstream and / or downstream sealing.

[0010] Yet another object of the present invention is to provide seals that operate over all temperature ranges, pressure ranges, and fluid types encountered in oil field applications.

[0011] Although gate valves are much lighter than BOPs, another object is to reduce the weight and size of the gate valve for the same size through-hole without sacrificing functionality. It would be desirable to reduce the number of parts and make the same size gate valve usable for many different applications.

[0012] In some cases, it is not known where the gate valve will be used or where it may be moved, making it problematic to select the appropriate seal. Yet another object is to be able to use the same gate valve for a desired through-hole size over all temperature ranges, pressure ranges, and fluid types encountered in oil field applications.

[0013] Another object is to have a two-way gate valve that has an upstream seal with a downstream backup seal. However, it is also a possible object that the gate valve can be converted to a downstream seal by simply removing one or more seals, as some users prefer a gate valve with only a downstream seal.

[0014] One general aspect includes a gate valve. The gate valve also includes a through-hole that extends through the gate valve. The valve also includes a body cavity that is oriented at a right angle to the through-hole in the gate valve. A gate is axially movable in the body cavity along an axis between an open position and a closed position. A valve stem is connected to the gate using a valve-stem to gate connection, and the valve stem is on a first side of the through-hole. The body cavity on the first side of the through-hole can include an oval cross-section portion and a first rectangular cross-section portion. The body cavity on a second side of the through-hole opposite the first side can include a second rectangular cross-section. The second rectangular cross-section of the body receives a rectangular cross-section of the gate. The gate can include a gate opening that aligns with the through-hole in the open position and a blank portion that aligns with the through-hole in the closed position. The blank portion has two flat sides. The valve also includes valve seats on both sides of the gate. The valve seats can have an opening therethrough and are in an encompassing relationship with the through-hole. Each valve seat has a sealing end that engages one of the two flat sides of the gate when the gate valve is closed. Additionally, each valve seat has an outer end opposite the sealing end that fits into a corresponding valve pocket in the gate valve. The gate width between the two flat sides of the blank portion of the gate is greater than the valve seat width between the sealing end and the outer end of each valve seat. Each valve seat can have at least one non-elastomeric U-shaped seal that is oriented such that the opening of the at least one non-elastomeric U-shaped seal on each valve seat faces the gate and forms a downstream seal. Thus, when the gate is closed, at least one non-elastomeric U-shaped seal on the downstream side of the gate is positioned to receive fluid pressure into the opening for sealing, such that the gate valve forms a two-way gate valve with a downstream seal.

[0015] An embodiment may include one or more of the following features of a gate valve, wherein each seat may include two inelastic U-shaped seals that are oriented such that the openings of the inelastic U-shaped seals face away from each other. Each U-shaped seal has a spring for pushing the legs of the inelastic U-shaped seal outward. The two inelastic U-shaped seals are positioned to form an upstream seal and a downstream seal. The gate valve may be a two-way gate valve with an upstream seal and a downstream seal. The springs for each seat are positioned on the outer ends to push each seat toward the gate. Metal flanges are formed on the seat, between the two inelastic U-shaped seals. Two inelastic support rings directly adjacent to the metal flanges may be made of a material to serve as non-extrusion rings. Other retaining rings have legs that fit into slots formed in the seat. The gate valve may include two metal lips that are formed on the seat and hold the two inelastic support rings and the two inelastic U-shaped seals in place on the seat. The gate opening is adjacent to the valve stem-gate connection such that the gate opening is positioned between the blank portion and the valve stem-gate connection. The gate valve has skirts on each side of the gate that are mounted to allow the gate to slide relative to the skirts. When the gate is moved to the closed position, the skirts on each side of the gate cover the gate opening. Each skirt engages a corresponding seat. The valve stem-gate connection may include a non-threaded latch. The width of the gate between the two flat sides of the gate valve may be greater than the length between the sealing end and the outer end of each seat.

[0016] One general aspect includes a gate valve. The gate valve has a through-hole that extends through the gate valve. A body cavity in the gate valve is positioned at a right angle to the through-hole. A gate is movable in the body cavity along an axis between an open position and a closed position. The valve also has a valve stem that can be connected to the gate by a valve-stem to gate connection, where the valve stem is on a first side of the through-hole. The body cavity is on the first side of the through-hole and can include a generally circular cross-section portion and a first rectangular cross-section portion. The body cavity has a second rectangular cross-section on a second side of the through-hole opposite the first side. The second rectangular cross-section of the body receives a rectangular cross-section of the gate. The gate has a gate opening that aligns with the through-hole in the open position and a blank portion that aligns with the through-hole in the closed position. The blank portion has two flat sides. The valve also includes valve seats on both sides of the gate. The valve seats have an opening therethrough and are in an encompassing relationship with the through-hole. Springs are on the outer ends of each valve seat. Each spring engages corresponding walls on both sides of the gate in the gate valve. When closing the gate valve, each spring pushes the sealing end of each valve seat into engagement with one of the two flat sides of the gate. The width of the gate between the two flat sides is greater than the length between the sealing end and the outer end of each valve seat. The valve also includes at least one inelastic U-shaped seal that is mounted on at least one of the valve seats at a location forming a downstream seal.

[0017] Embodiments can include one or more of the following features of the gate valve, where each valve seat can include two inelastic U-shaped seals that are oriented such that the openings of the inelastic U-shaped seals face away from each other. The two inelastic U-shaped seals are positioned to form an upstream seal and a downstream seal. The gate valve is a two-way gate valve having an upstream seal and a downstream seal. The gate valve can include a non-metallic retaining ring that is positioned around the outer end of the valve seat and engages one of the two inelastic U-shaped seals. A metal flange extends radially outward from each valve seat and is positioned between the two inelastic U-shaped seals. A second non-metallic retaining ring is at the sealing end of the valve seat. The second non-metallic retaining ring can include a lip that extends into a groove formed around each valve seat. The gate valve can include: two metal grooves that are formed around each valve seat for each of the two inelastic U-shaped seals; and a metal flange that extends radially outward from each valve seat and is positioned between the two inelastic U-shaped seals. The gate opening is adjacent to the valve-stem to gate connection such that the gate opening is positioned between the blank portion and the valve-stem to gate connection. The valve-stem to gate connection can include a non-threaded latch. The gate valve can include skirts on each side of the gate, where the gate slides relative to the skirts. When moving the gate to the open position, the skirts on both sides of the gate cover the gate opening.

[0018] These and other objects, features, and advantages of the present invention will become apparent from the accompanying drawings, the description given herein, and the appended claims. However, it should be understood that the above-listed objects and / or advantages of the present invention are only intended to assist in understanding aspects of the present invention and are not intended to limit the present invention in any way. Therefore, they do not constitute a comprehensive or restrictive list of objects, and / or features, and / or advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The following detailed description and claims are only illustrative of the general invention. Without departing from the spirit and scope of the present invention, those skilled in the art will readily propose additional modes, advantages, and details of the present invention. By referring to the following detailed description considered in conjunction with the accompanying drawings, a more comprehensive understanding of the present invention and its many attendant advantages will be readily obtained, wherein like reference numerals refer to like parts, and in the drawings:

[0020] Figure 1 is a perspective view of a gate valve having a rectangular lower body cavity and an ovaloid upper body cavity according to an embodiment of the present invention;

[0021] Figure 2 is a side elevational view of a gate valve without a valve cover according to an embodiment of the present invention, showing the rectangular body cavity and not showing the ovaloid body cavity;

[0022] Figure 3 is a top view of a gate valve assembly looking down into the body cavity through the circular upper body cavity towards the rectangular lower body cavity according to an embodiment of the present invention;

[0023] Figure 4 is a side sectional view of a gate valve assembly according to an embodiment of the present invention, showing that the seat on the gate side in the rectangular body cavity may be thinner than the seat in the case of an ovaloid body cavity;

[0024] Figure 5 is a side view of a gate valve according to an embodiment of the present invention, showing two seats and a seal assembly in the rectangular portion of the body cavity on both sides of the gate;

[0025] Figure 6 is a side view of a possible seal assembly on one of the two seats of a gate valve assembly according to an embodiment of the present invention.

[0026] Figure 7 is an exploded perspective view of a seat of a gate valve having a seal assembly according to an embodiment of the present invention.

[0027] Figure 8Side view of another possible seal assembly on a valve seat of a gate valve according to an embodiment of the present invention.

[0028] Figure 9 Perspective view of a T-slot connector gate slidably assembled to a T-shaped valve stem connector of a gate valve according to an embodiment of the present invention.

[0029] Figure 10 Perspective view of a skirt assembly of a gate valve for preventing or restricting debris from entering the body cavity according to an embodiment of the present invention.

[0030] Figure 11 Partial cross-sectional perspective view of a skirt assembly of a gate valve inserted into the oval-shaped and rectangular portions of the body cavity to prevent debris from entering the body cavity when opening and closing the gate according to an embodiment of the present invention.

[0031] Figure 12 Cross-sectional view of a skirt assembly of a gate valve inserted into the circular and rectangular portions of the body cavity. Detailed Description

[0032] A detailed description of the present invention is provided herein. However, it should be understood that the present invention may be embodied in various forms. Accordingly, the specific details disclosed herein should not be construed as limiting, but merely as a basis for the claims and as a representative basis for teaching those skilled in the art to employ the present invention in virtually any appropriate detailed system, structure, or manner.

[0033] Now referring to the drawings, and more particularly to Figure 1 , there is shown a gate valve 100 having a valve body 18. Inside the valve body 18 is a body cavity 16, which includes an upper body cavity 28 with an oval-shaped cross-section and a lower body cavity 38 with a rectangular cross-section. A through-hole 36 (also oval-shaped) extends through the gate valve 100 and is perpendicular to the body cavity 16. The valve cover 17 also defines a part of the upper body cavity 28 with an oval shape. The bottom plate 21 is the bottom of the upper body cavity 28 with an oval shape and the starting part of the rectangular body cavity 38, and includes a rectangular throat portion 19 of the body cavity 16 above the through-hole 36. In other words, there is a first rectangular cross-sectional part of the body cavity directly above the through-hole 36, but as shown in the figure, from the bottom plate 21 upwards, the body cavity 16 is oval-shaped. Although the entire upper body cavity 28 can be rectangular (as Figure 2 shown), it has been found advantageous that the upper body cavity 28 is oval-shaped, as discussed below. The oval-shaped body cavity can be circular or elliptical.

[0034] The gate 20 includes flat sides 26 that contact the body cavity 16 and the valve seat 70. In one possible embodiment, the gate 20 has an opening 22 in the upper portion of the gate. The opening 22 is the open position of the gate valve 100 and allows fluid to flow through the through hole 36 when aligned with the through hole 36. The blank seal surface 24 is on the side of the gate 20 opposite the opening 22 and blocks fluid flow and seals the through hole 36 when aligned with the through hole 36.

[0035] The gate 20 is provided with an approximately circular opening 22 having the same size as the through hole 36, so that fluid can flow through the gate in the open position and fluid flow is blocked in the closed position. In a preferred embodiment, when the gate is vertically oriented as shown, this opening is located in the upper portion of the gate 20. One benefit of having the opening 22 at the top of the through hole is the use of a skirt 60 that reduces the amount of debris entering the body cavity 16. See Figures 10 to 12 , which surrounds the gate 20 and engages the gate in a sliding manner. During movement between the open position and the closed position, the skirt prevents debris from collecting in or moving around the body cavity 16. Another practical benefit of having an opening at the top allows all gate valve sizes to be simplified due to the reduced number of different parts required. This standardization of reducing the number of parts required for different sizes of gate valves reduces the inventory requirements and time required to manufacture gate valves for a desired application (i.e., manufacturing a 2-inch gate valve, a 4-inch gate valve, or a 5-inch gate valve for a specific environment).

[0036] The valve seat 70 is positioned between the gate 20 and the valve body 18, on both sides of the gate 20. The gate engages the metal valve seat 70 to provide a metal-to-metal seal with the valve seat. The metal-to-metal seal operates within a wide range of temperatures, pressures, and fluid types encountered in oilfield operations. Leakage around the valve seat 70, between the valve seat and the valve body 18, and in the valve pocket 32 is discussed below.

[0037] The gate valve 100 can be manually operated by using a rotary handle 12. However, a power operator can also be utilized. In this case, the handle 12 is connected to the valve stem 14 of the valve, and the valve stem rotates to raise or lower the gate 20.

[0038] More specifically, continuing the above discussion, the body cavity 16 can be divided into two parts: an upper approximately circular or circular cavity side 28 above the bottom plate 21 and a lower rectangular cavity side 38 below the bottom plate 21. The upper body cavity 28 can have a circular cross-section, an oval cross-section, an elliptical cross-section, etc. Although an oval cross-section can reduce the body size, reduce the number of studs, etc. to maximize the weight / dimension reduction, it may be easier to manufacture using a circular cross-section body cavity.

[0039] The advantage of the generally circular cross-section of the upper body cavity 28 over a rectangular cross-section is that the upper body cavity 28 can be better filled with grease or other suitable lubricants to facilitate the movement and sealing of the gate within the cavity. It should be appreciated that since the upper circular body cavity 28 is larger in size compared to a rectangular upper body cavity, more grease can be utilized, thereby providing more lubrication and blocking debris from the fluid flow through the through-hole 36. During the opening and closing of the gate, debris can enter the body cavity 16 due to accumulation in the gate opening 22.

[0040] The gate 20 has a rectangular cross-section that fits tightly with the rectangular cross-section of the lower body cavity 38. As Figure 3 shown, a view of the rectangular cross-section of the lower body cavity 38 is visible when looking down at the valve from the top (where the valve cover is removed). The rectangular cross-section body cavity 38 (which can also be referred to as the second rectangular cross-section portion) reduces the amount of material required to construct the gate valve for a given size of the through-hole 36 and thus reduces the weight. Another advantage of the rectangular body cavity is that the rectangular body cavity reduces the required seat width 62 of the valve seat 70 (see Figure 2 ), because these valve seats do not necessarily have to be wide enough to extend through the radius of the circular body cavity before reaching the valve pocket 32 in which the valve seat 70 is assembled. This also allows for a narrower gate 20 as discussed below.

[0041] The lower side 30 of the gate valve includes a rectangular body cavity 38. As explained above, using a rectangular body cavity allows for a valve seat with a smaller seat width 62 (and weight) and allows for a narrower gate. Compared to the gate width 63 ( Figure 2 ), the seat width 62 ( Figure 2 ) of the valve seat extending outward from the gate can be reduced. This in turn reduces the amount of material required for construction, the cost of construction, and the total weight of the gate valve.

[0042] Turning to Figure 2 , a side elevational view of a gate valve 100 according to an embodiment of the present invention is shown. The axis 74 passing through the body cavity 16 is perpendicular to the through-hole 36 and bisects the body cavity 16. During the opening and closing operations, the gate 20 moves axially along the axis 74. The axis 74 also bisects the gate 20. In Figure 2 , the gate 20 is axially positioned such that the opening 22 is aligned with the through-hole 36, thereby allowing fluid to flow through the through-hole 36.

[0043] The seat width 62 is the distance between the sealing end 61 and the outer end 65 of each valve seat. In prior art systems, generally circular cavities are commonly used with flat gates, which in turn require a wider valve seat. In one embodiment, the gate width 63 between the two flat sealing sides 26 of the gate 20 is greater than the seat width 62 between the sealing end 61 and the outer end 65 of each valve seat. Accordingly, using a rectangular body cavity provides the following advantages: reducing the amount of material required to manufacture an enlarged generally circular body cavity, reducing the weight of the valve for a through-hole 36 of the same size, reducing the size of the valve for a through-hole of the same size, and reducing the pressure rating of the gate valve. In this way, the weight of the valve body 18 can be reduced by approximately 32%. In other possible embodiments, the amount of weight reduction can also be greater than or less than 32%.

[0044] As an example, for a valve with a through-hole 36 having a diameter of 3 1 / 16 inches and a pressure rating of 15K, a prior art generally circular body cavity requires a valve seat width of approximately 5.5 inches and a gate width of 4.5 inches. In a new design with a rectangular body cavity for a through-hole 36 of the same size, the thickness 63 of the gate can be 2.62 inches, and the thickness 62 of the valve seat can be 1.6 inches. In this example, the seat width is 62% of the gate width. Accordingly, the seat width is less than 100% of the gate width, or less than 90% of the gate width, or less than 80% of the gate width, or less than 70% of the gate width, or can be any percentage within this range. This not only reduces the weight of the body, but also significantly reduces the weight of the gate and the valve seat. The thickness 63 of the gate is less than the diameter of the through-hole 36 and is 85% of the through-hole, or less than 90% of the through-hole, in this example.

[0045] Figure 3 A top view looking down into the body cavity 16 of the gate valve body 18 of a gate valve assembly 100 according to an embodiment of the present invention is shown. The circular cavity 28 portion of the body cavity 16 is formed within the upper portion of the body 18 that bottoms out at the bottom plate 21. The gate 20 is positioned within the circular cavity 28 and the rectangular body cavity 38. The gate 20 is rectangular, and its rectangular cross-section 40 is perpendicular to the axis 74. The gate 20 includes flat sealing sides 26 that engage valve seats (see Figure 1 and Figure 2 ). The rectangular gate 20 fits closely into the rectangular body cavity 38. The circular cavity 28 can also be filled with grease or other suitable lubricant, allowing for smoother operation and less wear during movement of the gate within the body cavity when the gate is moved from the open or closed position. As described above, making the upper body cavity generally circular allows for more grease compared to the case where the body cavity is rectangular at the top of the valve. However, according to the present invention, having a rectangular body cavity at the top of the valve would also be a possible design.

[0046] Go to Figure 4 , which shows a side cross-sectional view of a gate valve 100 according to an embodiment of the present invention. The body cavity 16 has a lower body cavity portion or rectangular body cavity 38 of rectangular shape, which is below the through hole 36 and on the second or lower side 30 of the gate valve. The upper body cavity portion of the body cavity 16 includes a circular cavity 28, which is above the bottom plate 21 and on the first or upper side 10 of the gate valve. In other embodiments, the upper body cavity portion may be oval or rectangular in shape.

[0047] In one embodiment, when the gate valve 100 is moved to the open position, the lower portion of the body cavity on the lower side 30 of the gate valve slidably receives the rectangular gate 20. In another possible embodiment, the gate 20 may have an opening 22 in the lower portion of the gate, and the blank is on the upper side of the gate 20. As shown, when the opening 22 is aligned with the through hole 36, the gate 20 is in the open position, thereby allowing fluid flow. When desired or needed, the gate 20 can be lowered by rotating the handle 12 connected to the valve stem 14 and further connected to the gate 20. The rectangular gate 20 will then move axially into the rectangular cavity 38. It should also be understood that the valve seat 70 has a reduced width. The rectangular body cavity shape brings the valve seat 70 closer to the gate 20 and eliminates the need for a valve seat retainer, which are used in some prior art gate valves. Eliminating the need for a valve seat retainer for holding the valve seat in position within the valve pocket 32 relative to the gate 20 further reduces the inventory requirements and time constraints for manufacturing a gate valve in accordance with the present invention.

[0048] In Figure 5 , a side view of a valve seat assembly 150 according to an embodiment of the present invention is shown. As shown, when the opening 22 is aligned with the through hole 36, the gate 20 is in the open position. The valve seat 70 is installed in the valve pocket 32 in the body 18. The upstream side is indicated by the flow arrow 42, while the downstream side is indicated by the flow arrow 44. When the gate 20 is moved to the closed position, the fluid flow in the through hole 36 is blocked by the flat side of the blank section 24 of the gate 20 (see Figure 1 ). The upstream seals 48, 46 and the downstream seals 66 and 68 prevent fluid from flowing around the valve seat 70 and between the valve seat and the valve body 18. However, only one upstream seal and one downstream seal are used for each flow direction.

[0049] For example, if the valve is closed, the upstream seal 46 prevents fluid from flowing between the upstream valve seat and the body 18. If the seal 46 fails, malfunctions, or is not installed, fluid may flow around the upstream valve seat and around the gate 20 past the seal 48, but will be sealed by the downstream seal 68. In other words, the U-shaped upstream seal 48 and the downstream U-shaped seal 68 (the open ends of the two seals pointing upstream) block the fluid flow as indicated by the flow arrow 42. The benefit of using two seals is that the sealing ability is stronger due to redundancy in the case where the upstream seal does not prevent fluid flow. In other words, if the upstream seal 46 prevents fluid from flowing around the upstream valve seat 70, the downstream seal 68 will not seal or will not be used to prevent fluid flow at that moment.

[0050] Some purchasers of valves prefer to have only a bi-directional downstream seal in the gate valve. Thus, in the example above, the seals 46 and 66 are removed so that only the downstream seal is utilized. In that way, when the valve is closed, the downstream seal 68 will seal between the downstream valve seat and the body 18 to prevent leakage past the downstream valve seat. If only a bi-directional upstream seal is desired, the seals 48 and 68 can be used. If for some reason only a single-direction seal (e.g., upstream seal) is desired, then all seals except the seal 46 can be removed. Thus, the seal configuration can be changed according to user preference, but for bi-directional redundant sealing, all seals are to be installed. Manufacturing the valve seat assembly 150 in the manner described herein allows for a standardized parts assembly that meets a variety of different sealing requirements (i.e., only downstream seal requirements, only upstream seal requirements, or bi-directional seal requirements) without the need to manufacture a different valve seat assembly 150 for each individual desired application.

[0051] It should be understood that if the fluid flow is reversed, the seal 66 becomes the upstream seal and the seal 48 becomes the downstream backup seal around the valve seat. Thus, the valve is bi-directional and effectively operates for fluid flow in either direction. Depending on the direction of fluid flow in the through-hole 36, only two seals are operative. This configuration is optimal for use under varying conditions.

[0052] In Figure 6 and Figure 8In it, the components of the valve seat seals 46 and 48 are shown in more detail. The valve seat seals 66, 68 have the same construction. Each valve seat 70 includes a metallic valve seat body having a plurality of non-elastomeric seal members. In a preferred embodiment, the metallic valve seat body of the valve seat 70 is itself Inconel metal. The seal members include PTFE seals having stainless steel springs to energize the downstream seals, and support rings and retaining rings of PEEK material for both the upstream and downstream seals. By eliminating elastomeric O-rings, the gate valve will have a longer service life as maintenance requirements are reduced while being able to withstand exposure to more extreme conditions. The operating temperature range is thus from -50 degrees Fahrenheit to 350 degrees Fahrenheit. These seal members are beneficial for all or nearly all fluids that will be encountered in oil fields, including corrosive fluids and acidic fluids. Further, these seals are beneficial for all pressures up to 20,000 psi. Also, this material will last for a long time. Thus, the problems associated with selecting the correct O-ring for the pressures, fluids, and temperatures that will be encountered are eliminated. Also, the problem of replacing seals at regular intervals due to age is eliminated.

[0053] Turning again to Figure 6 , an enlarged side view of the valve seat 70 according to an embodiment of the present invention is shown. If fluid attempts to flow behind the valve seat 70 as indicated by arrow 79, then the seal 46 will prevent the fluid from flowing. This would be Figure 5 the situation discussed in

[0054] If the direction of fluid flow is opposite to that shown in Figure 5 and has leaked through the upstream seal 66, then as indicated by the fluid flow arrow 81 towards the valve seat 70, the fluid is guided towards the seal 48 that seals around the valve seat.

[0055] As in Figure 6 it may be more than Figure 7Better shown, a sealing assembly of a U-shaped seal 48 and a support ring 72 used with a valve seat 70 on one side of a metal flange 73 is held in place by a retaining ring 56. The retaining ring can be a non-metallic or non-elastomeric retaining ring. The retaining ring 56 is snapped or pressed into place by inserting legs 59 extending from the retaining ring 56 into slots 57. The retaining ring 56 holds the U-shaped seal 48 and the support ring 72 in place against the metal flange 73 of the valve seat 70. Preferably, since the support ring 72 is made of a material harder than the base region 41 of the U-shaped seal 46 and the base region 43 of the U-shaped seal 48, the support ring also provides an anti-extrusion or non-extrusion function. The support ring can be non-elastomeric. In this embodiment, it is not necessary to snap the retaining ring 76 into place on the side opposite the retaining ring 56, because the valve body 18 is operable to hold the U-shaped seal 46 and the corresponding support ring 75 in place. The support rings 72 and 75 are directly adjacent to the metal flange 73 and are between the U-shaped seal 46 and the U-shaped seal 48. When the gate is closed to seal the through hole 36, the sealing end or surface 82 of the valve seat 70 engages one of the flat sides of the flat side of the gate 20. An outer spring 78 at the outer end 84 of the valve seat 70 pushes the valve seat 70 against the gate 20 to form an initial seal. The radial length of the outer end 84 is greater than the radial length of the sealing end 82, such that the pressure between the valve bladder wall 32 and the outer end 84 generates a force that pushes the valve seat 70 towards the gate 20, so that when the gate is closed, as the pressure in the through hole 36 rises, the valve seat is held firmly against the gate.

[0056] As a possible example of operation, fluid flow in the direction of arrow 81 can flow through the retaining ring 56 to the U-shaped seal 48, whereby the pressure of the fluid causes the U-shaped seal 48 to expand and open to block the fluid from traveling outside the seal. The actual seals 47 and 49 on the ends of the leg expansion spring 52 are formed of PTFE as discussed above. The leg expansion spring 52 is used to hold the seals in engagement with the metal wall of the valve bladder 32 and to hold them in the proper orientation for proper sealing. The spring 52 expands the seals 47 and 49 so that they press against the body 18 inside the valve bladder 32 to create an initial seal. The pressure generated within the U-shaped seal 48 due to the pressure in the through hole 36 pushes the wings or legs of the spring 52 open, such that the seal 49 maintains a high-pressure seal. The higher the pressure in the through hole 36, the greater the force generated on the seal 49 due to the pressure within the U-shaped interior of the seal, thereby increasing the opening of the U-shaped interior. The spring 52 can be constructed of stainless steel or other suitable material.

[0057] The outer spring 78 is installed on the side of the valve seat 70 opposite to the gate 20 to create an initial tension or pressure between the valve seat and the gate 20, thereby creating an initial metal-to-metal seal between the flat side of the gate 20 and the face or sealing end 82 of the valve seat 70.

[0058] Go to Figure 7 , which shows an exploded perspective view of a valve seat 70 with a sealing assembly according to a possible embodiment of the present invention. The combination of the valve seat 70 and the corresponding seal can be referred to as a valve seat assembly. As discussed above, the valve seat assembly further includes an outer spring 78 that is used to press the valve seat 70 against the gate to create an initial tension, thereby forming an initial metal-to-metal seal between the gate surface and the metal surface of the valve seat 70.

[0059] In one possible embodiment of the seal ring assembly, the retainer ring 56 can be pressed into place to hold the positions of a plurality of other rings and hold the valve seat against the valve body in place. Opposite the retainer ring 56 is the retainer ring 76. The seal rings 48 and 46 are operable to expand to prevent fluid flow. The seals are operable for two-way sealing. These seal rings can be made of PTFE and have stainless steel springs that help press the seals against the body for a stronger sealing ability. Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene and has many applications. Compared with the prior art rubber rings, the use of PTFE allows for a wider range of temperatures, pressures, and conditions. These seals can also be referred to as non-elastomeric seals. The advantages provided by non-elastomeric seals are: fewer maintenance requirements, a wider temperature range, and a wider range of chemical compatibility compared to elastomers. Therefore, the use of non-elastomeric seals will allow the operator to use a set of rings for a more extensive variety of applications, thereby reducing the time for seal replacement, lowering maintenance costs, and increasing operational flexibility. Since the valve seat 70 will be able to be used for multiple applications instead of having a separate valve seat 70 for each different application, the number of parts required to maintain inventory for multiple applications is significantly reduced. The anti-extrusion support rings 72, 75 and the retainer rings 56 and 76 can be made of PEEK material. PEEK is a semi-crystalline thermoplastic with excellent mechanical and chemical resistance properties that are maintained at high temperatures.

[0060] In Figure 6 , the outer retainer rings 56, 76 are used to form outer barriers that include the seal rings 48, 46 on the valve seat 70, while in Figure 8 , the valve seat metal body itself includes metal outer barriers or lips that include the seal rings on the valve seat 70.

[0061] Bring Figure 6 and Figure 8Comparison shows different seal assemblies. Fewer seal rings are required because there is no need for outer valve seat retainer rings 56, 76 to hold the valve seat in place relative to the gate. As can be seen in Figure 8 , the use of lip 54 eliminates retainer ring 56.

[0062] In this embodiment, U-shaped seal rings 46, 48 can be slidably installed past lip 54 using a tapered tool (not shown). In other words, the tapered tool has a smaller diameter such that the U-shaped seal ring is placed on the tapered tool and the diameter of the tapered tool smoothly increases to the diameter of the lip. The U-shaped seal slides along the tapered tool until the seal is sufficiently compressed to slip past lip 54 (such as a metal lip) near the sealed side or metal lip 55 on the opposite side. If an attempt is made to install the U-shaped seal ring without a tool, the U-shaped seal is very likely to be damaged because the U-shaped portion will be forced together as the dimensions of the lip are set outside the circumference where the diameter of the U-shaped seal can slip past without damage.

[0063] Lip 54 projects into the channel or gap to allow the seal to slide into place while also performing the function of the no-longer-needed retainer ring 56 ( Figure 6 ). Additionally, at the end opposite lip 54, retainer ring 76 has been omitted. Similarly, lip 55 similar to lip 54 has been added to perform the function of the retainer ring that has been removed in this embodiment. Thus, fewer parts need to be assembled while maintaining the same function.

[0064] In Figure 9 , a perspective view of the gate of a gate valve according to an embodiment of the present invention is shown. In one possible embodiment, gate 20 is generally rectangular and includes flat side 26 and rectangular cross-section 40 as previously discussed. Gate 20 has opening 22 and blank seal area 24 which will provide a seal when aligned with the through-hole or the opening will allow fluid to flow through the through-hole when aligned with the through-hole. As discussed above, the valve seat forms a metal-to-metal seal with blank seal area 24. When the gate is vertically oriented, a T-slot (which can also be referred to as a valve stem connector, gate connector, valve stem-gate connection) or latch 58 can be located at the top. Connector 58 can be milled or forged into gate 20. Connector 58 also has a corresponding connector on the valve stem for insertion into connector 58. T-slot 58 can be a non-threaded latch to allow the valve stem to slide or press into the connection on gate 20. This type of connector can provide additional strength and stiffness to the gate and the connection between the gate and the valve stem, and additionally, reduce the time required to assemble the gate valve.

[0065] Go to Figures 10 to 12 shows various views of a skirt assembly for a gate valve 100 according to an embodiment of the present invention. When the gate is closed, the skirt 60 covers the opening 22 of the gate 20. In this way, the skirt 60 prevents dirt, debris, etc. that may be trapped in the opening 22 during operation from entering the body cavity 16 when the valve is closed. This prevents dirt or debris from contaminating the body cavity, which could otherwise cause blockage, impede, or otherwise hinder the operation of the gate valve. Additionally, the use of the skirt 60 ensures proper operation and increases the operating time while reducing the downtime required for cleaning and maintaining the gate.

[0066] In one possible embodiment, as Figure 10 shown, the skirt 60 is constructed of a rectangular frame complementary to the gate 20. As seen in Figures 11 to 12 , the skirt 60 is inserted into the body cavity 16 and above the gate 20, where the skirt is fixed in place relative to the valve body 18. The skirt 60 has two sides or skirt panels 81 that slidably engage the gate, thereby sealing the cavity from contamination. The skirt 60 includes two semi-circular recesses 83 to allow for a tight engagement with the valve seat 70. The skirt has a circular opening 85 at the top to allow for the connection of the valve stem and the gate. The skirt 60 can be constructed of metal or other suitable material that is elastic enough to withstand the pressures and temperatures present during downhole operations.

[0067] In Figure 12 , it can be seen that the two sides 81 of the skirt 60 extend through the circular or oval-shaped cavity 28, past the bottom plate 21 of the oval-shaped cavity 28, and engage the valve seat 70. As explained above, when the gate is opened and debris is trapped in the opening 22 of the gate, then the sides 81 prevent the debris from entering the body cavity. Also as discussed above, the body cavity is preferably filled with grease to further prevent debris from entering the body cavity.

[0068] When comparing the prior art valve to the present invention, both the gate and the valve seat of the improved gate valve assembly are thinner because the overall body cavity dimensions have been reduced. The advantages provided are weight reduction and size reduction for a specific through-hole size, operating over a very wide range of temperatures, pressures, and fluids. Moreover, compared to prior art gate valves, there is a limited need for maintenance because individual components do not have to be replaced as they are generally compatible with the current parameters of the application.

[0069] Further, the reduction in the number of parts and the wider range of temperature, pressure, and fluid operations allow the same valve to be used in many different types of applications. There are 980 options when considering size, pressure rating, and material class; and 3,920 combinations when considering size, pressure, material, and temperature. However, there are at least 38,000,000,000 possible valve combinations that may be required for a desired application, depending on orifice size, pressure rating, temperature rating, material class, PSL rating, PR rating, third-party requirements, API specifications, stud connection requirements, overlays, service media, surface or subsea environment, model, end connection type, operator type, indicator type, and valve seat skirt. Frequently, multiple models with different designs need to be manufactured to meet these options. By standardizing parts based on temperature rating, material class, PSL rating, stud connection requirements, overlays, model, indicator type, and valve seat skirt, the present invention is able to reduce the number of possible combinations for the gate valves to be produced to less than 17,000,000. This reduces the engineering costs required to build each valve for a specific application and even allows the inventory of valves and their associated components to be maintained. The present invention may potentially reduce the number of models required to fully meet the desired parameters outlined above.

[0070] Currently, based on API standards, there are 4 different temperature range options for valves: 1) P+U (-20°F to 250°F), 2) P+X (-20°F to 350°F), 3) L+U (-50°F to 250°F), and 4) L+X (-50°F to 350°F). The present invention uses only elastomeric seals that meet the L+X option and thus also cover the other 3 temperature options (see Figure 7 ). This eliminates 3 of the 4 inventory options previously required to manufacture gate valves.

[0071] For material classes DD through FF, the present invention removes 6 options that were previously time-consuming to keep in inventory (either expensive to manufacture or made on demand) by standardizing the current material class options consisting of 1.5, 360, and "unrestricted" H2S partial pressure to only the "unrestricted" option. Further standardization of material classes AA through CC is consistent with the teachings herein that teach a method for reducing the inventory requirements and time for manufacturing gate valves.

[0072] As discussed herein, in reference to Figure 6 and Figure 8When it is, the valve seat 70 is made of Inconel alloy. When considering the valve seat weight and wall thickness design factors, the valve seat geometry of the valve seat 70 can be combined for the following valve sizes and pressure ratings: 1) 2": A valve seat design for 5KSI applications, 10KSI applications, 15KSI applications, and 20KSI applications; 2) 3": A valve seat design for 5KSI applications, 10KSI applications, 15KSI applications, and 20KSI applications; 3) 4": A valve seat design for 5KSI and 10KSI, a valve seat design for 15KSI and 20KSI; 4) 5": A valve seat design for 5KSI and 10KSI, a valve seat design for 15KSI and 20KSI.

[0073] In addition, the manufacture of the gate for manual valves, hydraulic valves, and fail-safe shut-off valves can be standardized to use only Inconel alloy and 4140 steel, and the holes are on the upper part of the gate 20. When considering the gate weight and wall thickness design factors, the gate geometry can be combined for the following valve sizes and pressure ratings: 1) 2": A gate design for 5KSI applications, 10KSI applications, 15KSI applications, and 20KSI applications; 2) 3": A gate design for 5KSI applications, 10KSI applications, 15KSI applications, and 20KSI applications; 3) 4": A gate design for 5KSI and 10KSI, a gate design for 15KSI and 20KSI; 4) 5": A gate design for 5KSI and 10KSI, a gate design for 15KSI and 20KSI.

[0074] In addition, the valve stem can be standardized to use only Inconel alloy and 4140 steel. When considering the valve stem weight and wall thickness design factors, the valve stem geometry can be combined for the following valve sizes and pressure ratings: 1) 2": A valve stem design for 5KSI applications, 10KSI applications, 15KSI applications, and 20KSI applications; 2) 3": A valve stem design for 5KSI applications, 10KSI applications, 15KSI applications, and 20KSI applications; 3) 4": A valve stem design for 5KSI and 10KSI, a valve stem design for 15KSI and 20KSI; 4) 5": A valve stem design for 5KSI and 10KSI, a valve stem design for 15KSI and 20KSI.

[0075] By standardizing parts based on temperature ratings, material classes, PSL levels, stud connection requirements, overlays, models, indicator types, and seat skirts as described above, the present invention is able to reduce the number of possible combinations for gate valves from over 38,000,000,000 to less than 17,000,000, reducing over 2,000 factors in the possible combinations. This reduces the engineering costs required to build each valve for a particular application and even allows for the ability to maintain an inventory of valves. This results in faster delivery speeds.

[0076] In summary, the gate valve 100 uses a rectangular lower body cavity 38. The upper body cavity 28 can be generally circular. The seats 70 are narrow, and the width of these seats can be much less than the width of the gate 20. The non - elastomeric U - shaped seal provides a bi - directional upstream seal with a downstream backup seal. The skirt 60 prevents debris from entering the body cavity 16.

[0077] The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and those skilled in the art will appreciate that various changes can be made in the dimensions, shapes, and materials of the various core elements and in the combination of details or features of the shown construction without departing from the spirit of the invention. Additionally, the scope of this patent is not limited to its literal meaning but encompasses all equivalents of the recited claims.

Claims

1. A gate valve, comprising: A through hole that extends through the gate valve in the gate valve; A body cavity that is oriented transversely to the through hole in the gate valve and, when the gate valve is upright, extends from above the through hole to below the through hole in the gate valve; A gate that can axially move between an open position and a closed position along an axis passing through the body cavity in the body cavity; A valve stem that is connected to the gate by a valve stem-gate connector; The gate includes a gate opening that aligns with the through hole in the open position and a blank portion that aligns with the through hole in the closed position, the blank portion including two sides; And Skirts mounted in the body cavity on each side of the gate, a top plate connected to each skirt, the size and position of each skirt being set to cover the gate opening when the gate moves to the closed position; the top plate further includes an opening therein through which the valve stem or the valve stem-gate connector extends.

2. The gate valve according to claim 1, further comprising: The blank portion includes two flat sides, valve seats are on both sides of the gate, each valve seat includes an opening therethrough and is in an enclosing relationship with the through hole, each valve seat includes a sealing end that engages one of the two flat sides of the gate when closing the gate valve, and wherein each skirt engages a corresponding valve seat.

3. The gate valve according to claim 2, further comprising semi-circular ends on each plate that engage each corresponding valve seat.

4. The gate valve according to claim 1, wherein, The body cavity is filled with grease to reduce debris entering the gate opening.

5. The gate valve according to claim 1, wherein, The body cavity includes at least two flat surfaces below the through hole that slidably receive the gate when the gate valve is upright.

6. The gate valve according to claim 5, further comprising: The at least two flat surfaces are part of a rectangular cross-section.

7. The gate valve according to claim 5, wherein, The at least two flat surfaces extend beyond a substantial portion of the body cavity above the through hole.

8. The gate valve according to claim 1, wherein, The body cavity includes an oval shape above the through hole.

9. The gate valve according to claim 1, wherein, Each skirt is made of an elastic material.

10. The gate valve according to claim 1, wherein, The gate is mounted such that when the gate valve is upright and in the closed position, the gate opening is above the through hole.

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