Patent Publication Number: US-2015060715-A1

Title: Gate Valve Seal Ring

Description:
BACKGROUND 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     In certain applications, a structure (e.g., a wireline or tubing) may obstruct closure of a valve, such as a gate valve. Under certain conditions, it may be desirable to cut the wireline or tubing to enable closure of the valve while retaining the valve&#39;s sealing integrity over an extended period of use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying figures in which like characters represent like parts throughout the figures, wherein: 
         FIG. 1  is a schematic diagram of an exemplary gate valve having seal rings, in accordance with embodiments of the present disclosure; 
         FIG. 2  is a cross-sectional schematic diagram of a seal ring, in accordance with embodiments of the present disclosure; 
         FIG. 3  is a cross-sectional schematic diagram of a seal ring, in accordance with embodiments of the present disclosure; 
         FIG. 4  is a cross-sectional, schematic diagram of a seal ring, in accordance with embodiments of the present disclosure; and 
         FIG. 5  is a cut away perspective view, taken along line  5 - 5  of  FIG. 4 , of a seal ring, in accordance with embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     One or more specific embodiments of the present invention will be described below. These described embodiments are only exemplary of the present invention. Additionally, in an effort to provide a concise description of these exemplary embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     The following disclosure relates to an exemplary improved seal ring that has a seat ring supported by a seat holder. That seat ring may be formed from a hard, corrosion resistant material, such as metals, metal alloys, ceramics, ceramic metals (i.e., cermets), or any combination thereof, for example. Particular examples of a hard, corrosion resistant material are Stellite™ (e.g., cobalt-based alloys and/or cobalt-chromium alloys), tungsten carbide, stainless steel, carbides, nitrides, or other material designed for corrosion resistance and/or wear resistance. Moreover, the Stellite™ may include cobalt, nickel, iron, aluminum, boron, carbon, chromium, manganese, molybdenum, phosphorus, sulfur, silicon, titanium, or any combination thereof. 
     The seat ring may be retained within the seat holder by a seal, such as an O-ring, a shrink fit material and/or method, a snap-fit, threads, an interference fit, or other retaining material and/or method. In certain embodiments, the seat ring may be formed from an existing seal ring. For example, an existing seal ring (e.g., a previously used seal ring) may be machined or modified to form the seat holder mentioned above. Thereafter, the seat holder may be fitted with the seat ring, and the seat ring may be retained within the seat holder by a sealing material, a shrink fit material and/or method, a snap-fit, an interference fit, or other retaining material and/or method. In this manner, existing or previously used (e.g., previously used in the field) seal rings may be re-used, refurbished, recycled, or otherwise improved, thereby reducing costs associated with manufacturing and/or maintaining gate valves. 
       FIG. 1  illustrates an embodiment of a gate valve  10  having improved seal rings  12 . The gate valve  10  is generally configured to control a flow of fluid in various applications. For example, the gate valve  10  may be employed in applications relating to oil and gas industries, power generation industries, petrochemical industries, and the like. In oilfield applications, the gate valve  10  may be coupled to a Christmas tree (not shown) that controls the extraction of production fluid from a well. The gate valve  10  has a bore (e.g., bore  30 ) that may be sized for the given application. For example, the bore of the gate valve  10  may be at least approximately 3 inches in diameter. In other embodiments, the gate valve  10  includes a smaller bore that may be less than approximately 5 inches. In certain embodiments, the gate valve  10  is configured to operate at a high pressure of at least approximately 10,000 pounds per square inch (psi). In some embodiments, the gate valve  10  is configured to operate at pressure lower than approximately 10,000 psi. Additionally, in certain embodiments, the gate valve  10  may be used to shear a wireline, coil tubing, or other obstruction. That is, the gate valve  10  may be configured to apply a shearing force to break the obstruction and allow for travel of a gate  22 . 
     In the illustrated embodiment, the gate valve  10  includes an actuator  14 . The actuator  14  may be coupled to a top portion of a valve body  18  via a bonnet  20 , or the actuator  14  can be directly coupled to the valve body  18 . The body  18  may be constructed of cast iron, ductile iron, cast carbon steel, gun metal, stainless steel, alloy steels, corrosion resistant alloys, and/or forged steels. The gate valve  10  includes a gate  22  disposed within a cavity  24  of the body  18 . As will be appreciated, the gate  22  is configured to move (e.g., axially translate) between an open position and a closed position within the cavity  24 . As illustrated, the gate  22  is disposed in the open position. In certain embodiments, the gate  22  has a rectangular cross-sectional profile. The body  18  of the gate valve  10  includes an inlet  26  and an outlet  28  configured for a flow of a fluid through a bore  30  of the body  18  into a passage  32  of the gate valve  10 . In certain embodiments, the outlet  28  may act as an inlet allowing fluid flow into the passage  32  from either side of the gate valve  10 . For example, in some embodiments, the inlet  26  may act as an outlet and the outlet  28  may act as an inlet. 
     Additionally, as mentioned above, the gate valve  10  may be configured to shear a wireline, coil tubing, or other tubular member. In the illustrated embodiment, a wireline  34  extends through the bore  30  and the passage  32  of the body  18  of the gate valve  10 . When the gate  22  of the gate valve  10  moves (e.g., axially translates) from an opened position to a closed position, the gate  22  shears the wireline  34 , thus allowing the gate  22  to close without removing the obstruction, here the wireline  34 . 
     In the illustrated gate valve  10 , the actuator  14  provides the motive force to open and close the valve  10 . In particular, the actuator  14  applies a force (e.g., a linear axial force) to a stem  36  coupling the gate  22  to the actuator  14 . In this manner, the gate  22  moves (e.g., in an axial direction  37 ) from the open position shown in the illustrated embodiment to a closed position. For example, the actuator  14  may include a spring, a hydraulic piston, a manually actuated mechanism (e.g., hand wheel), or other actuation system (e.g., spring-biased actuator, electrical actuator, magnetic actuator, or any combination thereof) 
     As the gate  22  moves (e.g., axially translates) from the open position to the closed position, the wireline  34  is sheared against the improved seal rings  12 . These seal rings  12  include a seat ring supported by a seat holder. The seat ring may be formed from a hard, corrosion resistant material, examples of which have been discussed above. 
     As shown, each of the improved seal rings  12  is disposed in a respective recess  38  formed in the body  18  of the gate valve  10 . More specifically, one improved seal ring  12  is disposed on an upstream side of the gate  22  in the respective recess  38 , and another improved seal ring  12  is disposed on a downstream side of the gate  22  in the respective recess  38 . The improved seal rings  12  may each include one or more seals (e.g., spring-loaded lip seals) disposed between the respective recess  38  of the body  18  and the improved seal ring  12 . Additionally, each improved seal ring  12  may include a seat holder that supports a seat ring. More specifically, the seat ring may be formed from a hard, corrosion resistant material designed for corrosion resistance and/or wear resistance, examples of which have been discussed above. In certain embodiments, the seat ring of each improved seal ring  12  may be replaceable, thereby reducing costs associated with maintaining, repairing, and/or replacing the improved seal rings  12 . Additionally, in certain embodiments, existing seal rings may be used to form the seat holder of the improved seal ring  12 . In this manner, existing seal rings may be retrofitted to form the improved seal ring  12 , thereby recycling and improving existing seal rings. 
       FIG. 2  illustrates an embodiment of the improved seal ring  12  having a seat holder  50  supporting a seat ring  52 . As mentioned above, in certain embodiments, the seat ring  52  may be formed from a cobalt-based material, such as Stellite™, or other hard, corrosion resistant material designed for corrosion resistance and/or wear resistance. For example, the seat holder  50  and the seat ring  52  may each have an annular configuration and may be disposed within an annular recess  54  formed in the seat holder  50 . In other words, the seat ring  52  is an insert positioned within the recess  54  rather than a coating of the seat holder  50 . As such, the whole surface of the seat holder  50  may not be coated with a corrosion resistant and/or wear resistant material. In the illustrated embodiment, the recess  54  is formed in a radially inward surface  56  of the seat holder  50  and a gate  22  ( FIG. 1 ) facing surface  58  of the seat holder  50 . The seat ring  52  is disposed and retained within the recess  54  of the seat holder  50 , such that the seat holder  50  and seat ring  52  cooperatively form the annular improved seal ring  12  ( FIG. 1 ). During operation, a gate-facing surface  60  of the seat ring  52  may abut and rub against the gate  22  ( FIG. 1 ) of the gate valve  10  ( FIG. 1 ). As will be appreciated, the cobalt-based material (e.g., Stellite™) used to form the seat ring  52  may be wear resistant and corrosion resistant. As a result, the seat ring  52  and the improved seal ring  12  may have improved longevity and useful life. 
     As mentioned above, the seat ring  52  is supported by the seat holder  50  and retained within the recess  54  of the seat holder  50 . For example, in the illustrated embodiment, the seat ring  52  is retained within the recess  54  of the seat holder  50  at least partially by a seal, a lock ring, or a retaining ring  62 . More specifically, the seal  62  has a face seal configuration. In other words, the seal  62  is disposed at least partially between an axial surface  64  of the recess  54  and the seat ring  52 . The seal  62  is disposed at least partially between a radial surface  66  of the recess  54  and the seat ring  52 . As such, the seal  62  is disposed in a corner  68  of the recess  54 . In certain embodiments, the seal  62  may be an O-ring, other annular seal, or other face seal. The seal  62  operates to create an interference or friction fit between the seat holder  50  and the seat ring  52 . As a result, the seat ring  52  may be retained within the recess  54  of the seat holder  50 . In certain embodiments, the seat holder  50  (e.g., the radial surface  66  of the seat holder  50 ), the seat ring  52  (e.g., circumferential surface of the seat ring  52 ), and the seal  62  may be assembled to form the improved seal ring  12 , and heat may be subsequently applied to the assembled improved seal ring  12  to improve (e.g., cure) the interference fit created between the seat holder  50 , the seat ring  52 , and the seal  62 . In other embodiments, the seat holder  50 , the seat ring  52 , and the seal  62  may be assembled to form the improved seal ring  12  in a low temperature environment (e.g., using liquid nitrogen). After the improved seal ring  12  is assembled, the improved seal ring  12  may be removed from the low temperature environment, and as the improved seal ring  12  components (e.g., the seat holder  50 , the seat ring  52 , and the seal  62 ) increase in temperature, the interference fit created between the seat holder  50 , the seat ring  52 , and the seal  62  may be improved (e.g., cured). 
     Furthermore, in certain embodiments, the seat holder  50  may be heated and the seat ring  52  may be cooled before assembly. Heating the seat holder  50  may cause thermal expansion in the seat holder  50  and cooling the seat ring  52  may cause thermal contraction in the seat ring  52 . After assembly, the seat holder  50  and the seat ring  52  may return to ambient temperature to create the interference fit to seal and/or hold between the seat holder  50  (e.g., radial surface  66  of seat holder  50 ) and the seat ring  52  (e.g., circumferential face of seat ring  52 ). In other words, the seat holder  50  may cool, thereby causing thermal contraction in the seat holder  50 , and the seat ring  52  temperature may rise, thereby causing thermal expansion in the seat ring  52 . In this manner, the seat holder  50  and the seat ring  52  may engage with one another to form the interference fit. 
     As mentioned above, the improved seal ring  12  may be formed at least partially from existing seal rings. In this manner, existing seal rings  12  may be recycled and improved to form the improved seal ring  12 , thereby reducing costs associated with gate valve  10  maintenance. For example, in certain embodiments, an existing seal ring may be removed from the gate valve  10 , and the existing seal ring may be used to form the seat holder  50  of the improved seal ring  12 . In other words, an existing seal ring may be machined or modified to form the seat holder  50  having the recess  54  for supporting the seat ring  52 . Existing seal rings may be formed from a solid metal or a metal having a coating. As such, existing seal rings may be suitable for forming the seat holder  50  of the improved seal ring  12 . For example, the recess  54  may be formed by milling, grinding, turning, or other machining process. That is, an existing seal ring may undergo a machining process to create the recess  54 . In this way, the exiting seal ring may be repurposed for use as the seat holder  50  of the improved seal ring  12 . After the recess  54  is created, the seat ring  52  may be positioned within the recess  54  and retained by the seal  62 , as described above. 
     In other embodiments, the seat holder  50  may be newly formed. In other words, the seat holder  50  may not be created from an existing seal ring. For example, the seat holder  50  may be cast or otherwise formed form metal to include the recess  54 . After the seat holder  50  is formed, the seat ring  52  made of a material, such as a cobalt-based material or other hard, corrosion resistant and/or wear resistant material may be positioned and retained within the recess  54  to form the improved seal ring  12 . 
     The improved seal ring  12  may include other features, such as recesses  70  configured to support seals (e.g., spring loaded lip seals) between the improved seal ring  12  and the recess  38  of the body  18  of the gate valve  10 . Additionally, the illustrated embodiment of the improved seal ring  12  also includes a chamfered edge  72  formed in the gate  22  facing surface  58  of the improved seal ring  12 . The chamfered edge  72  may improve installation and translation of the improved seal ring  12  between the body  18  and the gate  22  of the gate valve  10 . 
       FIG. 3  illustrates an embodiment of the improved seal ring  12  having the seat holder  50  supporting the seat ring  52 . As mentioned above, the seat ring  52  is formed from a material, such as a hard, corrosion resistant material (e.g., Stellite™ or other cobalt-based material). As similarly discussed above, in the illustrated embodiment, the seat ring  52  is retained within the recess  54  of the seat holder  50  by the seal  62  (e.g., O-ring). However, in the illustrated embodiment, the seal  62  has a radial configuration. That is, the seal  62  (e.g., annular seal) is positioned between the radial surface  66  of the recess  54  and the seat ring  52 . As discussed in detail above, the seal  62  may create an interference or friction fit between the seat holder  50  and the seat ring  52 , thereby retaining the seat ring  52  within the recess  54 . 
       FIG. 4  illustrates an embodiment of the improved seal ring  12  having the seat holder  50  supporting the seat ring  52 . As mentioned above, the seat ring  52  is formed from a hard, corrosion resistant and/or wear resistant material, such as Stellite™ or other cobalt-based material. In the illustrated embodiment, the seat ring  52  is retained within the recess  54  of the seat holder  50  by a shrink fit material  100 . Specifically, the shrink fit material  100  is positioned between the seat ring  52  and the radial surface  66  of the recess  54 . However, in other embodiments, the shrink fit material  100  may also be positioned between the axial surface  64  of the recess  54  and the seat ring  52 . 
     As similarly described above with respect to the seal  62 , the shrink fit material  100  creates an interference fit between the seat holder  50  and the seat ring  52 . As will be appreciated, the interference fit may be created by the shrink fit material  100  upon the heating or cooling of the shrink fit material  100  after the seat holder  50 , the seat ring  52 , and the shrink fit material  100  are assembled to form the improved seal ring  12 . For example, after the seat holder  50 , the seat ring  52 , and the shrink fit material  100  are assembled, heat may be applied to the shrink fit material  100  to cause the shrink fit material  100  to expand between the seat holder  50  and the seat ring  52 . Furthermore, during assembly of the improved seat ring  12 , the shrink fit material  100  may be cooled to cause thermal contraction of the shrink fit material  100 . Thereafter, when the shrink fit material  100  returns to ambient temperature, the shrink fit material  100  may expand to create an interference fit between the seat holder  50  and the seat ring  52 , thereby retaining the seat ring  52  within the recess  54  of the seat holder  50 . 
     In certain embodiments, the shrink fit material  100  may be a sleeve or have an annular configuration, such that the shrink fit material  100  fits around a circumference of the seat ring  52 . In other embodiments, multiple, non-continuous pieces of shrink fit material  100  may be positioned between the seat ring  52  and the seat holder  50  during assembly of the improved seal ring  12 . 
       FIG. 5  is a partial cut away perspective view, taken along line  5 - 5  of  FIG. 4 , of an embodiment of the improved seal ring  12  having the seat ring  52  retained within the recess  54  of the seat holder  50 . As shown, the seat ring  52  and the seat holder  50  each have an annular configuration. As discussed in detail above, the seat ring  52  may be retained within the recess  54  of the seat holder  50  by created in interference fit between the seat ring  52  and the seat holder  50 . For example, the seal  62  ( FIG. 3 ) and/or the shrink fit material  100  may be positioned between the seat ring  52  and the seat holder  50  to generate the interference fit between the seat ring  52  and the seat holder  50 . 
     As discussed above, in certain embodiments, the seat holder  50  of the improved seat ring  12  may be created by recycling an existing seat ring. That is, an existing seat ring may be machined to formed the recess  54  therein, and the existing seat ring with the recess  54  may serve as the seat holder  50 . In this manner, existing seat rings may be recycled and repurposed to form the improved seat ring  12 , thereby reducing costs associated with improving and/or maintaining the gate valve  10 . Furthermore, in certain embodiments, the seat ring  52  of the improved seal ring  12  may be replaceable. As such, the seat holder  50  may be reused and the seat ring  52  may be replaced as desired, thereby reducing costs associated with maintaining the improved seal ring  12 . For example, the seat ring  52  may be removed from the recess  54  and replaced with a newer seat ring  52 . 
     Embodiments of the present disclosure include the improved seal ring  12  for the gate valve  10 . More specifically, the improved seal ring  12  includes the seat ring  52  supported by the seat holder  50 . For example, as discussed in detail above, the seat ring  52  may be formed from a hard, corrosion resistant and/or wear resistant material, such as Stellite™, other cobalt-based alloy, or other alloy designed for wear resistance. The seat ring  52  may be retained within the seat holder  50  by the seal  62 , such as an O-ring, the shrink fit material  100 , and/or other retaining material. In certain embodiments, the improved seal ring  12  may be formed from an existing seal ring. For example, an existing seal ring may be machined or modified by form the seat holder  50 . Thereafter, the seat holder  50  may be fitted with the seat ring  52 , and the seat ring  52  may be retained within the seat holder  50  by a sealing material (e.g., seal  62 ), a shrink fit material (e.g., shrink fit material  100 ), or other retaining material. In this manner, existing seal rings may be re-used, refurbished, recycled, or otherwise improved, to form the improved seal ring  12 , thereby reducing costs associated with manufacturing and/or maintaining gate valves  10 . 
     While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.