Patent Publication Number: US-2018045618-A1

Title: Diamond sintered sampling relief valve

Description:
BACKGROUND 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the presently described embodiments. 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 embodiments. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     In order to meet consumer and industrial demand for natural resources, companies often invest significant amounts of time and money in finding and extracting oil, natural gas, and other subterranean resources from the earth. Particularly, once a desired subterranean resource such as oil or natural gas is discovered, drilling and production systems are often employed to access and extract the resource. These systems may be located onshore or offshore depending on the location of a desired resource. Hydrocarbons are then transported for processing and refining. 
     In the hydrocarbon processing industry, analytical instrumentation is employed at various stages of processing to analyze the chemical composition of the fluids being transported and processed. Typically, the instrumentation analyzes a small sample taken from a hydrocarbon fluid stream. Sampling equipment, whether in-line or in a bypass loop, can be subject to severe erosion due to the volume of samples obtained and particulates in the samples. 
     SUMMARY 
     Certain aspects of some embodiments disclosed herein are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below. 
     Some embodiments of the present disclosure generally relate to a sampling relief valve. In one embodiment, the relief valve includes a valve body having a fluid passage therethrough and a stem disposed in the valve body so as to control flow in the fluid passage. The relief valve can also include a seat and a spring disposed in the valve body, with the spring biasing the stem toward the seat. Further, at least a portion of the stem of the relief valve includes a diamond sintered material. 
     Certain embodiments of the present disclosure generally relate to a system including a bypass loop for receiving a fluid. In one embodiment, the system also includes one or more sample receivers and a sample extractor having a fluid inlet and a fluid outlet. The sample extractor can obtain a sample of the fluid in the bypass loop to deposit to the one or more sample receivers. The system also includes a sampling relief valve coupled between the fluid outlet and the one or more sample receivers. The sampling relief valve includes a valve body having a fluid passage therethrough and a stem disposed in the valve body to control flow in the fluid passage. At least a portion of the stem of the relief valve is formed of a diamond sintered material. The relief valve also includes a seat positioned in the valve body so as to seal against the stem when the stem is in a closed position against the seat. 
     Still further embodiments of the present disclosure generally relate to a method that includes providing a stem base and a seat of a check valve. The method can also include providing diamond sintered material about the stem base of the check valve and permanently affixing the diamond sintered material about the stem base. Further, the method can also include disposing the stem base and diamond sintered material in a body of the check valve such that the diamond sintered material of the stem abuts the seat of the check valve. 
     Various refinements of the features noted above may exist in relation to various aspects of the present embodiments. Further features may also be incorporated in these various aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the above-described aspects of the present disclosure alone or in any combination. Again, the brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of some embodiments without limitation to the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of certain embodiments will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  generally depicts a sample extractor; 
         FIGS. 2A-2C  depict a sample extractor system in use in a bypass loop of a pipeline; 
         FIG. 3  shows an external relief valve, in accordance with embodiments of the present disclosure, as can be used in the sample extractor system shown in  FIG. 2A-2C ; 
         FIG. 4  shows a cross-section of the external relief valve of  FIG. 3  in accordance with one embodiment; and 
         FIGS. 5A and 5B  show certain components of an external relief valve in accordance with embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     Specific embodiments of the present disclosure are described below. In an effort to provide a concise description of these 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. 
     When introducing elements of various embodiments, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Moreover, any use of “top,” “bottom,” “above,” “below,” other directional terms, and variations of these terms is made for convenience, but does not require any particular orientation of the components. 
     In pipeline sampling, a sampling check valve can be externally mounted at the outlet of a sample extractor device in a bypass loop. An external sampling check valve may be referred to herein as a “relief valve.” The relief valve opens each time the sample extractor extracts a sample, which may be on the order of 15,000 times a day. The relief valve provides sample size integrity and prevents leakage. In practice, the stem and seat of a relief valve may be subjected to extremely high velocity fluid across the stem and seat, and to sediment or sand in the sampled process product (e.g., crude oil). The relief valve may be set for between 100 and 1500 PSIG. Valves resilient to erosion have been attempted, including valve components of stainless steel, titanium nitride, or tungsten. In some cases, however, the resulting valve constructions may still fail quickly due to erosion or may be too expensive to manufacture for the particular application. 
     The present disclosure contemplates a relief valve having a stem component and a seat component. In some embodiments, at least a portion of the stem is formed of a diamond sintered material. For instance, in one embodiment the relief valve includes a ring of diamond sintered material affixed about the end of the stem to address erosion where the stem meets the seat. In some instances, the seat may also, or instead, include a diamond sintered material, such as at the surface where the stem and seat meet. 
     A sample extractor, such as sample extractor  100  of  FIG. 1 , extracts samples from liquids flowing in a nominal bypass line. Commercially available sample extractors may be powered by hydraulic power or air pressure. In an example configuration, a two-inch bypass loop bypasses a main pipeline, and sample extractor  100  obtains one-cc samples of product such as crude oil, refined hydrocarbons, and non-corrosive chemicals from the bypass loop. Sample extractors that obtain two-cc samples are also in common usage. Sample extractor  100  includes an actuation component  101 . 
     The function of a sample extractor, such as sample extractor  100 , is well established and known by one of ordinary skill in the art. In an idle state, as shown in  FIG. 2A , process product is free to flow through the sampler body  102  by way of the bypass line  108 . When the sample extractor  100  is energized, air pressure (or hydraulic pressure) forces a piston of the actuation component  101  downward. The downward movement of the piston of the actuation component  101  forces a capture tube  104  downward through a chamber  110  of the body  102  to pass over a lower capture tube seal, thereby trapping a grab sample  123  of product (e.g., a one-cc or two-cc sample), as shown in  FIG. 2B . Once the grab sample  123  is trapped by the capture tube  104 , the grab sample  123  is pushed by sample tube  106  out the bottom of the sampler body  102  (as shown in  FIG. 2C ) through a check valve  112  internal to the sample extractor  100 , out to external relief valve  114 , and then to sampler receiver  116 . 
     When the sample extractor  100  is de-energized, air is vented and applied to the underside of the piston of the actuation component  101 , returning the capture tube  104  and sample tube  106  to their starting positions. The piston of actuation component  101  also returns to its starting position, with any vacuum relieved via a breaker incorporated into the sample tube  106 . Process product continues to pass through the sampler body  102 , and the sample extractor  100  is then ready for a subsequent grab. 
       FIG. 3  depicts an example external relief valve  114  in accordance with embodiments of the present disclosure, as can be used with the sample extractor system shown in  FIGS. 2A-2C . The body  115  of the relief valve  114  can be a stainless steel body.  FIG. 4 , in turn, is a cross-section of the external relief valve  114  of  FIG. 3 . The relief valve  114  is spring-biased with spring  118  maintaining the relief valve  114  in a closed position. A passage  120  through the body  115  of the relief valve  114  fluidly connects an inlet  124  and an outlet  125 . When a pressure differential between the inlet  124  and outlet  125  overcomes the spring force of spring  118  (e.g., when sample tube  106  expels a fluid sample out of the sample extractor  100  to the relief valve  114 ), the relief valve  114  opens and the stem  126  moves away from the seat  128 . The passage  120  through the body  115  of the relief valve  114  is closed when the stem  126  is in a closed position against the seat  128  (e.g., as shown in  FIG. 4 ). In some embodiments, such as that shown in  FIG. 4 , the stem  126  may be formed entirely of a diamond sintered material. The seat  128  can also be formed (completely or partially) of a diamond sintered material in some instances. 
       FIG. 5A  shows another embodiment of an external relief valve  114  in closer detail in a closed position, without the body  115 . The spring  118  biases the stem  126  into the closed position against the seat  128 . In this embodiment, the stem  126  includes a base  127 . The stem base  127  may be formed of a traditional material such as a nickel alloy, tungsten carbine, steel, or another suitable material. An outer ring  132  is disposed about the base  127  at the end of the stem  126 . In one example embodiment, the outer ring  132  has a thickness on the order of five mm, and a height on the order of five mm. The outer ring  132  comprises a diamond sintered material, such as a polycrystalline diamond material. The outer ring  132  may be manufactured by combining diamond crystals (optionally synthetic) with metal powder, and then sintering the combination under pressure and at high temperature. The outer ring  132  may enable the stem  126  to better withstand erosion from sediment experienced by the stem, when compared to traditional valve stems. In an embodiment, the outer ring  132  may be threaded onto the stem base  127 . Alternatively, the outer ring  132  may be brazed onto the stem base  127 . In still another embodiment, an adhesive may adhere the outer ring  132  to the stem base  127 . 
     Quad-ring  130  (or some other seal) is coupled to the seat  128 , such that quad-ring  130  seals about the stem  126  seating against the seat  128  in the closed position. In an optional embodiment, as shown, the seat  128  may also include a portion  134  of diamond sintered material on the inner surface of a seat base  129  of the seat  128  in the form of an inner ring  134 . In an example embodiment, the inner ring  134  may have a thickness and a height to approximately mirror the outer ring  132  on the stem  126 , such that the areas of the stem  126  and seat  128  that abut one another are the areas of diamond sintered materials. The inner ring  134  may be brazed onto the seat base  129  of the seat  128 . In still another embodiment, an adhesive may adhere the inner ring  134  to the seat base  129  of the seat  128 . 
       FIG. 5B  shows components of the external relief valve  114  of  FIG. 5A  in an open position. When the pressure differential between the inlet  124  and the outlet  125  overcomes the spring force of the spring  118 , the spring  118  is compressed, and the stem  126  moves apart from the seat  128 , allowing the fluid sample to pass through the relief valve  114 . 
     In an embodiment, the stem base  127  and/or seat base  129  may be machined (e.g., to remove a corner) to produce a recess for the outer ring  132  and inner ring  134 , respectively. Alternatively, the stem base  127  and/or seat base  129  may be forged to include a recess for the diamond sintered materials. In still further embodiments, the entirety of either the stem  126  or seat  128  may be formed of diamond sintered material, when cost effective. 
     Additionally, the diamond sintered material may include an angled pattern in the outer surface of the diamond sintered material in some instances. In still further embodiments, the diamond sintered material may be added to or layered on the stem base  127  and/or seat base  129  in any number of known ways, such as vacuum vapor deposition, sputtering and ion plating, methods of chemical vapor deposition, electrolytic plating, auto-catalytic plating, and the like. 
     While the aspects of the present disclosure 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. But 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.