Patent Publication Number: US-9416789-B2

Title: Valve cover geometry

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application having Ser. No. 61/910,470, which was filed Dec. 2, 2013. The aforementioned patent application is hereby incorporated by reference in its entirety into the present application to the extent consistent with the present application. 
    
    
     BACKGROUND 
     Compressors are often utilized in a myriad of applications and industrial processes to compress one or more process fluids (e.g., gases). Conventional compressors may often include a casing or cylinder having one or more valve assemblies (e.g., check valve assembly) configured to handle large volumes of the process fluids directed to and/or discharged from the compressor. The cylinder of the conventional compressors may often define one or more openings or bores and the valve assemblies may be disposed in the bores to handle the process fluids flowing therethrough. In operation, the process fluids contained in the cylinder of the compressors are often pressurized to relatively high pressures. Accordingly, the bores of the cylinders may typically include closure devices or covers configured to seal the bores to prevent leakage of the pressurized process fluids from the cylinder to the surrounding atmosphere. In addition to sealing the bores, the covers may also be configured to retain the valve assemblies within the bores of the compressors. 
     As advancements are made in the industrial processes, however, production requirements for the conventional compressors are often heightened. In many cases, to meet the heightened production requirements, the process fluids may be pressurized to relatively higher pressures. The higher pressures of the process fluids in the compressors may subsequently expose the cylinder and the covers sealing the bores and/or retaining the valve assemblies disposed therein to increased pressures. The covers in conventional compressors, however, may not be capable of sufficiently sealing the bores and/or retaining the valve assemblies disposed therein, thereby resulting in leakage of the process fluid from the cylinder to the surrounding atmosphere via the bores and/or the valve assemblies. Further, the covers in conventional compressors may not provide a means to monitor the leakage of the process fluids from the cylinders, which may present a hazardous and/or fatal environment for nearby operators. For example, the process fluids may often contain one or more hazardous gases (e.g., hydrogen sulfide), which have been proven to be fatal in quantities as small as 20 parts per million (ppm). In another example, the leaked process fluids may contain one or more volatile hydrocarbons, which may combine with the surrounding atmosphere in stoichiometric mixtures to provide a potentially explosive environment. 
     What is needed, then, are improved covers and methods for sealing bores defined in a cylinder of a compressor and/or retaining valve assemblies disposed in the bores that are capable of monitoring leakage of process fluids from the cylinder of the compressor. 
     SUMMARY 
     Embodiments of the disclosure may provide a closure device for monitoring leakage of a process fluid through a bore of a compressor casing. The closure device may include a body configured to be detachably coupled with the compressor casing about the bore of the compressor. The body may define a fluid passage and a plurality of grooves. The plurality of grooves may be defined about an outer circumferential surface of the body and may be axially spaced from one another. The closure device may also include a plurality of seals at least partially disposed in respective grooves of the plurality of grooves. The plurality of seals may be configured to engage an inner surface of the compressor casing such that adjacent seals of the plurality of seals at least partially define an annular gap therebetween fluidly coupled with the fluid passage and configured to contain the leakage of the process fluid. 
     Embodiments of the disclosure may also provide a compressor including a cylinder defining a cavity configured to contain a process fluid, a bore fluidly coupled with and extending from the cavity to and through an outer surface of the cylinder, and a channel fluidly coupled with and extending from the bore. The compressor may also include a valve assembly disposed in the bore and configured to control a flow of the process fluid between the channel and the cavity. The compressor may further include a closure device configured to be detachably coupled with the cylinder about the bore and to monitor leakage of the process fluid through the bore of the cylinder. The closure device may include a body defining a plurality of grooves about an outer circumferential surface thereof and axially spaced from one another. The closure device may also include a plurality of seals, where each seal of the plurality of seals may be at least partially disposed in a respective groove of the plurality of grooves. Each seal of the plurality of seals may be configured to engage an inner surface of the cylinder defining the bore such that adjacent seals of the plurality of seals at least partially define an annular gap therebetween. The annular gap may be fluidly coupled with a fluid passage at least partially extending through the body and configured to contain the leakage of the process fluid. 
     Embodiments of the disclosure may further provide a valve cover including a valve body having a domed portion and a flange extending from the domed portion. The flange of the valve cover may define a plurality of openings extending therethrough. The valve cover may also include an annular rib extending from the valve body. The annular rib may define a first groove and a second groove about an outer circumferential surface thereof and axially spaced from one another. A first seal may be at least partially disposed in the first groove, and a second seal may be at least partially disposed in the second groove. The first and second seals may at least partially define an annular gap therebetween configured to contain leakage of a process fluid. The valve body may define a fluid passage at least partially extending therethrough and fluidly coupled with the annular gap. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is best understood from the following detailed description when read with the accompanying Figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. 
         FIG. 1A  illustrates a partial cross-sectional view of a portion of a casing of a compressor having a valve assembly and a valve cover, according to one or more embodiments disclosed. 
         FIG. 1B  illustrates an enlarged view of the portion of the casing of the compressor indicated by the box labeled “ 1 B” of  FIG. 1A , according to one or more embodiments disclosed. 
     
    
    
     DETAILED DESCRIPTION 
     It is to be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures, or functions of the invention. Exemplary embodiments of components, arrangements, and configurations are described below to simplify the present disclosure; however, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the invention. Additionally, the present disclosure may repeat reference numerals and/or letters in the various exemplary embodiments and across the Figures provided herein. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various exemplary embodiments and/or configurations discussed in the various Figures. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. Finally, the exemplary embodiments presented below may be combined in any combination of ways, i.e., any element from one exemplary embodiment may be used in any other exemplary embodiment, without departing from the scope of the disclosure. 
     Additionally, certain terms are used throughout the following description and claims to refer to particular components. As one skilled in the art will appreciate, various entities may refer to the same component by different names, and as such, the naming convention for the elements described herein is not intended to limit the scope of the invention, unless otherwise specifically defined herein. Further, the naming convention used herein is not intended to distinguish between components that differ in name but not function. Further, in the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” All numerical values in this disclosure may be exact or approximate values unless otherwise specifically stated. Accordingly, various embodiments of the disclosure may deviate from the numbers, values, and ranges disclosed herein without departing from the intended scope. Furthermore, as it is used in the claims or specification, the term “or” is intended to encompass both exclusive and inclusive cases, i.e., “A or B” is intended to be synonymous with “at least one of A and B,” unless otherwise expressly specified herein. 
       FIG. 1A  illustrates a partial cross sectional view of a portion of a casing  102  of a compressor  100  including a closure device, such as a valve cover  110 , according to one or more embodiments. The casing  102 , illustrated as a cylinder in  FIG. 1A , may at least partially define a cavity  104  of the compressor  100  configured to contain one or more process fluids (e.g., gases and/or liquids). In at least one embodiment, a compressor piston (not shown) may be at least partially disposed in the cavity  104  and configured to reciprocate therein to compress the process fluids. The cylinder  102  may also at least partially define a bore  106  fluidly coupled with and extending from the cavity  104  of the compressor  100  to and through an outer surface  108  of the cylinder  102 , and a channel  112  fluidly coupled with and extending from the bore  106 . The channel  112  may be an inlet or an outlet of the compressor  100 . 
     In at least one embodiment, a valve assembly  114  including a valve  115  and a valve crab  117  may be at least partially disposed in the bore  106  and configured to control a flow of the process fluids between the cavity  104  and the channel  112 . For example, the cylinder  102  may define a shoulder  116  configured to at least partially support a first end portion  118  of the valve assembly  114 . The valve  115  may define or include a plurality of holes (not shown) extending therethrough and configured to provide fluid communication between the cavity  104  and the channel  112 . In at least one embodiment, one or more gaskets (not shown) may be disposed between the first end portion  118  of the valve assembly  114  and the shoulder  116 . The gaskets may be configured to prevent leakage of the process fluids between the valve assembly  114  and the shoulder  116 . The gaskets may include, but are not limited to, one or more metallic gaskets, elastomeric gaskets, or the like. 
     In at least one embodiment, the valve cover  110  may be detachably coupled with the cylinder  102  about the bore  106  and configured to seal the bore  106  and/or retain the valve assembly  114  within the bore  106  of the compressor  100 . For example, the valve cover  110  may include a body  120  configured to detachably couple the valve cover  110  with the cylinder  102 , and an annular rib  122  extending from the body  120  and configured to retain the valve assembly  114  within the bore  106  of the compressor  100 . The annular rib  122  may extend downwardly from the body  120  and be at least partially disposed in the bore  106  to engage and/or apply a force to a second end portion  124  of the valve assembly  114  to retain the valve assembly  114  within the bore  106  of the compressor  100 . The force applied to the second end portion  124  of the valve assembly  114  may retain or hold the first end portion  118  of the valve assembly  114  adjacent the shoulder  116  defined in the bore  106 . In at least one embodiment, the annular rib  122  may define a chamfered surface or edge  126  ( FIG. 1B ) configured to facilitate the insertion of the annular rib  122  into the bore  106 . For example, as illustrated in  FIG. 1B , the annular rib  112  may define the chamfered edge  126  at a first end portion  128  thereof to facilitate the insertion of the annular rib  122  into the bore  106  of the compressor  100 . 
     In at least one embodiment, the body  120  may be or include a plate or an annular disk having a uniform thickness. In another embodiment, the body  120  may include a domed or curved portion  130  and a flange portion  132  extending radially outward from the curved portion  130 . The flange portion  132  may be configured to detachably couple the body  120  of the valve cover  110  with the cylinder  102 . For example, as illustrated in  FIG. 1A , the flange portion  132  may extend over and be spaced outward from the outer surface  108  of the cylinder  102  and may define one or more circumferentially-arrayed openings (two are shown  134 ) extending therethrough. The openings  134  defined in the flange portion  132  may be configured to receive one or more mechanical fasteners, illustrated as studs  135  and nuts  136 . The studs  135  may extend into and engage corresponding threads formed in the cylinder  102  and the nuts  136  may be fastened to the studs  135  to couple the valve cover  110  with the cylinder  102 . In addition to, or in substitution of the studs  135  and the nuts  136 , the mechanical fasteners may include one or more bolts and/or any other known mechanical fasteners. In at least one embodiment, at least a portion of the force applied from the annular rib  122  to the second end portion  124  of the valve assembly  114  to retain the valve assembly  114  within the bore  106  of the compressor  100  may be provided by the studs  135  and the nuts  136 . For example, the torque applied to the nuts  136  to couple the valve cover  110  with the cylinder  102  may be increased or decreased to correspondingly increase or decrease the force applied to the second end portion  124  of the valve assembly  114 . 
     In at least one embodiment, the valve cover  110  may be configured to provide a fluid tight seal with the cylinder  102  to at least partially prevent leakage of the process fluids from the compressor  100  to an external environment (e.g., the atmosphere) via the bore  106 . For example, as illustrated in  FIG. 1B , the valve cover  110  may define two or more recesses or grooves (two are shown  138 ,  140 ) about an outer circumferential surface  142  of the annular rib  122  and having respective seals  144 ,  146  (e.g., O-rings) at least partially disposed therein. As illustrated in  FIG. 1B , a first groove  138  may be disposed near or proximal the first end portion  128  of the annular rib  122 , and a second groove  140  may be axially spaced from the first groove  138 . In at least one embodiment, a first seal  144  and a second seal  146  may be at least partially disposed in the first groove  138  and the second groove  140 , respectively, to provide the fluid tight seal between the valve cover  110  and the cylinder  102 . For example, the first and second seals  144 ,  146  may at least partially extend from the respective grooves  138 ,  140  to engage an inner surface  148  of the casing  102  defining the bore  106  to provide the fluid tight seal between the valve cover  110  and the cylinder  102 . In at least one embodiment, the first and second seals  144 ,  146  may at least partially define an annular gap  150  therebetween. For example, as illustrated in  FIG. 1B , the axially spaced seals  144 ,  146  may engage the inner surface  148  to define the annular gap  150 . 
     In at least one embodiment, the pressure exerted on or experienced by the first seal  144  may be at least partially determined by the pressure of the process fluids contained in the cavity  104 , the channel  112 , and/or the valve assembly  114  of the compressor  100 . Further, the pressure exerted on or experienced by the second seal  146  may be at least partially determined by the pressure of the process fluids contained in the annular gap  150  and/or the pressure of the exterior environment (i.e., atmospheric pressure). In an exemplary embodiment, the pressure exerted on the first seal  144  may be relatively greater than the pressure exerted on the second seal  146 . For example, the first seal  144  may provide a fluid tight seal between the valve cover  110  and the bore  106  sufficient to prevent all or substantially all of the process fluids from flowing or leaking from the cavity  104 , the channel  112 , and/or the valve assembly  114  to the annular gap  150 . Preventing all or substantially all of the process fluid from flowing or leaking to the annular gap  150  may subsequently prevent the pressure of the process fluids contained in the cavity  104 , the channel  112 , and/or the valve assembly  114  from being exerted on the second seal  146 . Accordingly, the first seal  144  may prevent the pressure of the process fluid contained in the cavity  104 , the channel  112 , and/or the valve assembly  114  from being exerted on the second seal  146 . In at least one embodiment, the second seal  146  may provide a fluid tight seal between the valve cover  110  and the bore  106  sufficient to prevent all or substantially all of the process fluids from flowing or leaking from the annular gap  150  to the external environment. 
     In at least one embodiment, the body  120  of the valve cover  110  may define a port or opening  152  along an outer surface  154  thereof that may be fluidly coupled with the annular gap  150 . For example, as illustrated in  FIGS. 1A and 1B , the valve cover  110  may define a fluid passage  156  extending between and fluidly coupling the opening  152  and the annular gap  150 . In at least one embodiment, illustrated in  FIG. 1A , the opening  152  may be fluidly coupled with one or more downstream processing systems  158  via a conduit or piping  160 . The downstream processing systems  158  may be configured to process and/or dispose of the process fluids leaked from the compressor  100  and/or the annular gap  150 . Accordingly, it may be appreciated that the downstream processing systems  158  may prevent the leakage of the process fluids from the compressor  100  and/or the annular gap  150  to the surrounding environment, thereby providing a safer environment for nearby operators. 
     As previously discussed, the first seal  144  may prevent the relatively greater pressure of the process fluid contained in the cavity  104 , the channel  112 , and/or the valve assembly  114  from being exerted on the second seal  146 . In at least one embodiment, the increased pressure of the process fluids exerted on the first seal  144  may cause the process fluids to diffuse into at least a portion of the first seal  144 . During one or more decompression events (e.g., blow down events) the process fluids contained in the first seal  144  may depressurize and rapidly expand therein, thereby compromising the structural integrity of the first seal  144 . For example, the depressurization and rapid expansion of the process fluids within in the first seal  144  may cause the first seal  144  to rupture (i.e., explosive decompression). In at least one embodiment, the second seal  146  may be configured to maintain the fluid tight seal between the valve cover  110  and the cylinder  102  upon failure of the first seal  144 . Accordingly, the process fluids traversing past the ruptured first seal  144  may be retained in the annular gap  150  by the second seal  146 , and subsequently exhausted to the one or more downstream processing system  158  via the fluid passage  156  and the piping  160 . 
     In at least one embodiment, one or more devices  162  may be fluidly coupled with or disposed in the piping  160 . For example, as illustrated in  FIG. 1A , the devices  162  may be fluidly coupled with the piping  160  between the compressor  100  and the downstream processing systems  158 . Illustrative devices  162  may include, but are not limited to, one or more flow meters, gas monitors, gas detectors, pressure sensors, or any other devices desirable for monitoring, processing, and/or outputting information related to the leakage or flow of the process fluids from the compressor  100  and/or the annular gap  150 . In an exemplary embodiment, the devices  162  include a flow meter, such as a Venturi flow meter, a Coriolis flow meter, a pressure flow meter, stroke counter, impeller flow meter, or the like, or any combination thereof. The flow meter may be configured to monitor or measure the volumetric flow and/or the mass flow of the process fluids leaking from the compressor  100  and/or the annular gap  150 . 
     The foregoing has outlined features of several embodiments so that those skilled in the art may better understand the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.