Abstract:
An apparatus for mounting a pipe sensor is disclosed. The apparatus comprises a pipe and a sensor. The pipe has a pipe wall with a section removed defining a passage through the pipe wall. The sensor has a collar, is disposed in the passage, and is exposed to the interior of the pipe. In one embodiment, the sensor can be welded to the pipe wall. In another embodiment, an insert can be disposed in the passage between the sensor and the pipe wall, with a locking nut engaged with the insert and pressing upon the collar to fasten the sensor to the insert.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to pipe sensors, and particularly to pipe-mounted sensors for detecting characteristics internal to the pipe. 
         [0002]    Sensors can be used in determining characteristics inside pipes and piping systems, such as pressure, flow volume, flow rate, temperature, moisture and humidity, and fluid concentration, amongst others. The sensors can be integral in providing measurement and control of fluids in the pipes, and in maintaining efficient and accurate operations. Efficient control and operation in commercial industries can be essential in maintaining human safety, environmental safety, and cost efficiency. 
         [0003]    In industries such as the oil industry, the sensors are mounted to the pipes using industry standard pipe connections, which are often large flanges on the end of a length of pipe. These flanges are bolted or screwed together at a union or joint. A sensor is attached to the flange, and the flange is connected to another flange at the end of a jointed pipe, so that the sensor is exposed to the internal area of the pipe. Because the pipe connections used for connecting sensors are also used for connecting other standard pipe equipment (e.g. pipes), the pipe connections (e.g. flanges) are very large relative to the sensors. These pipe connections can be particularly large, or otherwise onerous, in some industries, such as the subsea oil industry or other industries with relatively harsh operating environments that necessitate numerous or strict regulations, and/or stronger or more durable pipe connections. 
         [0004]    Because the pipes and other pipe equipment can be very large relative to the sensors, a relatively large amount of space is occupied to connect the small sensors to the pipes. Space to fit sensors attached by large flanges can become very crowded, or be too small, limiting the number of sensors that can be used in a given area, and limiting the control and operation of the pipe system. Adding sensors or relocating sensors after the initial design of a pipe system can be very difficult and expensive. Furthermore, larger pipe connections require a larger amount of material, which is costly. 
         [0005]    It would be advantageous to attach sensors within pipes without the limitations of using bulky pipe connections. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0006]    An apparatus for mounting sensors within pipes is provided that avoids using bulky pipe connections. 
         [0007]    In one embodiment, an apparatus for mounting a pipe sensor comprises a pipe, an insert, a sensor, and a locking nut. The pipe has a pipe wall. The pipe wall has a section removed that defines a passage through the pipe wall. The insert is disposed in the passage and is fastened and sealed to the pipe wall. An inner surface of the insert defines a cavity in the insert. The inner surface has a tapered portion. The sensor has a collar, is disposed in the cavity of the insert, is fastened and sealed to the insert, and is exposed to the interior of the pipe. A locking nut is engaged with the insert and pressed upon the collar to fasten and seal the sensor to the insert. 
         [0008]    In another embodiment, an apparatus for mounting a pipe sensor comprises a pipe and a sensor. The pipe has a pipe wall with a section removed that defines a passage through the pipe wall. The sensor is disposed in the passage and exposed to the interior of the pipe. The sensor has a collar which is welded to the pipe wall to form a fluid-impermeable seal between the collar and the pipe wall. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    So that the manner in which the features of the invention can be understood, a detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting of its scope, for the scope of the invention encompasses other equally effective embodiments. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of invention. Thus, for further understanding of the invention, reference can be made to the following detailed description, read in connection with the drawings in which: 
           [0010]      FIG. 1  is an exploded side view of a sectioned pipe wall of a pipe, with a sensor that can be embedded in the pipe wall in an exemplary embodiment of the invention using an insert and a locking nut. 
           [0011]      FIG. 2  is a side view of a sectioned pipe wall of a pipe, with a sensor embedded in the pipe wall, in one exemplary embodiment of the invention corresponding to  FIG. 1 . 
           [0012]      FIG. 3  is an exploded side view of a sectioned pipe wall of a pipe, with a sensor that can be embedded in the pipe wall, in another exemplary embodiment of the invention. 
           [0013]      FIG. 4  is a partially sectioned side view of a pipe wall with a sensor embedded in the pipe wall, in one embodiment corresponding to  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]      FIG. 1  is an exploded side view of a sectioned pipe wall  12  of a pipe  10 , with a sensor  30  that can be embedded in the pipe wall  12  in an exemplary embodiment of the invention using an insert  20  and a locking nut  40 . The sensor  30  can be one from a variety of sensors. Some such devices include pressure sensors, flow rate meters, flow volume meters, temperature meters, moisture and humidity meters, sand or mud detectors, and fluid concentration meters. An example of a sensor that can be mounted according to this method includes a piezoresistive pressure sensor with a piezoresistive transducer. Another example of a sensor includes a resonating device, such as a trench etched resonant pressure sensor (“TERPS”). The sensors can be shaped variously. In one embodiment, the diameter or width of a sensor tip  33  is approximately 0.5 inches (12.7 mm). The sensor tip  33  can be exposed to the interior  16  of the pipe  10 . The sensor  30  can have a collar  38 , or a collar  38  can be fastened to the sensor  30 , such as by welding the collar  38  to and/or around the sensor  30 . The sensor  30  can have a tapered surface  39  between the collar  38  and the sensor tip  33 . The sensor  30  can have or can be attached to electrical wires  36  to communicate electrical signals from the sensor  30 . 
         [0015]    The pipe wall  12  can be made of a material suitable for the particular application. In the subsea oil industry, for example, steel, a superalloy, or another high-performance alloy, such as an austenitic nickel-chromium-based superalloy can be used. Other materials suitable for the application and industry can also be used. The pipe wall  12  can be of varying thicknesses. In one example of a subsea oil drilling application, the pipe wall  12  can be between 0.25 inches (6.35 mm) and 0.375 inches (9.525 mm) thick. A section of the pipe wall  12  can be removed, such as by boring a hole through the pipe wall  12 , to create a passage  14  through the pipe wall  12  from an outer surface  19  of the pipe wall  12  to an inner surface  18  of the pipe wall  12 . 
         [0016]    The insert  20  can be sized and shaped on the outside to fit into the pipe wall  12  in the passage  14 . For instance, if the passage  14  is cylindrical, then outer surface  22  of the insert  20  can be shaped cylindrically as well, and dimensioned so the insert  20  can fit snugly in the passage  14 . Alternatively, the passage  14  of the pipe wall  12  can be shaped and sized to receive the insert  20 . 
         [0017]    The insert  20  can be shaped and sized to accommodate receiving the sensor  30 . The insert  20  can have a cavity  25  into which the sensor  30  can be inserted. The cavity  25  can be defined by an inner surface  23  of the insert  20 . The inner surface  23  can comprise an internally threaded portion  26 , and a tapered portion  21 . The threaded portion  26  can be positioned along the inner surface  23  at the end of the insert  40  radially outward from the center axis of the pipe  10 , and the tapered portion  21  can be positioned along the inner surface  23  at the end of the insert  40  radially inward toward the center axis of the pipe  10  from the threaded portion  26 . The length of the insert  40  in the radial direction of the pipe  10  can be longer than the thickness of the pipe wall  12  to ensure enough space for the threaded portion  26  and the tapered portion  21 , and to provide extra support in securing the sensor  30  when the insert  20  is inserted and fastened in the pipe wall  12 . The thickness of the insert  20  between the inner surface  23  and an outer surface  22  can be sufficient to accommodate the threaded portion  26  and to provide structural strength (e.g. to reduce stress, bending, or breaking, etc.) at the thinnest portion. Resultantly, the insert  20  can be only slightly larger at it largest diameter or widest point than the sensor  30 , using less material and leaving more room around the pipe  10  to locate other sensors  30 , if desirable. In this way, sensors  30  can be positioned at multiple points circumferentially around the pipe  10 , or in multiple points along the longitude of the pipe  10 , to map pipe, fluid, and/or flow characteristics three dimensionally. 
         [0018]      FIG. 2  is a side view of a sectioned pipe wall  12  of a pipe  10 , with a sensor  30  embedded in the pipe wall  12 , in one exemplary embodiment of the invention corresponding to  FIG. 1 . 
         [0019]    The insert  20  can be inserted into the passage  14  of the pipe wall  12  so that the radially inwardly facing surface  28  is approximately flush with the inner surface  18  of the pipe wall  12 , extended beyond the inner surface  18  of the pipe wall  12 , or recessed into the pipe wall  12 . Positioning the radially inwardly facing surface  28  of the insert  20  approximately flush with the inner surface  18  of the pipe wall  12 , as illustrated, can reduce any effect the insert  20  has on the flowing fluid in the pipe  10 . Positioning the radially inwardly facing surface  28  of the insert  20  so that the insert  20  extends into the pipe  10  beyond the inner surface  18  of the pipe wall  12  or so that the insert  20  is recessed in the pipe wall  12  can accommodate physical constraints engaging the pipe  10 , the insert  20 , the sensor  30 , and the locking nut  40 , or can accommodate any limitations of the sensor  30 . Once positioned, the insert  20  can be secured in the pipe wall  12  by welding or other known methods suitable for the structural requirements and the materials of the pipe  10  and the insert  20 . Welding can include but is not limited to gas tungsten arc welding and electric arc welding. The securement can yield a fluid seal between the insert  20  and the pipe wall  10  that is capable of withstanding high pressures up to and exceeding 10,000 psi (68,947,573 Pa), 15,000 psi (103,421,359 Pa), or 20,000 psi (137,895,146 Pa). 
         [0020]    The sensor  30  can be inserted into the insert  20 , so that the sensor tip  33  is exposed to the inside of the pipe  10  and any fluid in the pipe  10 . As with the insert  20 , the sensor tip  33  can be approximately flush with the inside surface of the pipe wall  12 , recessed into the pipe wall  12 , or extended beyond the inside surface of the pipe wall  12 , depending on the design preferences and the operating conditions desirable for the sensor  30 . Positioning the insert  20  and the sensor  30  flush with the inside diameter of the pipe wall  12  can reduce impact on the flow conditions of the fluid in the pipe  10 . 
         [0021]    To obtain the proper position of the sensor  30 , the locking nut  40  with externally threaded portion  42  that engages the internally threaded portion  26  of the insert  20  is tightened radially inward to depress upon the collar  38  of the sensor  30  and force the sensor  30  radially inward. The tapered surface  39  of the sensor  30  impacts and is pressed against the tapered portion  21  of the insert  20 , making a seal, and positioning the sensor  30 . The seal can withstand high pressures, including pressures in excess of 10,000 psi (68,947,573 Pa), 15,000 psi (103,421,359 Pa), or 20,000 psi (137,895,146 Pa), and beyond. The locking nut  40  can also be unscrewed and disengaged, allowing the sensor  30  to be easily removed and/or replaced with another sensor  30 , for instance, if the sensor  30  fails. 
         [0022]    The insert  20  can be made of a suitable material, such as a type of steel, a superalloy, or another high-performance alloy, such as an austenitic nickel-chromium-based superalloy. The insert  20  can be harder than the sensor  30  so that when the tapered surface  39  of the sensor  30  impacts and seals against the tapered portion  21  of the insert  20 , the insert  20  is less likely to be compromised, bent or otherwise damaged. The insert  20  can then be reusable in removing and/or replacing the sensor  30 . Alternatively, the insert  20  can be softer than the sensor  30 , so that the sensor  30  is less likely to be compromised, bent, or otherwise damaged. 
         [0023]    A housing  60  can be placed over the sensor  30 , the locking nut  40 , and the insert  20 . The housing  60  can be secured to the pipe  10  so that the housing  60  protects the sensor  30  and any electronic components. The housing  60  can seal out water, other fluids, contaminants, or destructive agents. 
         [0024]      FIG. 3  is an exploded side view of a sectioned pipe wall  12  of a pipe  10 , with a sensor  30  that can be embedded in the pipe wall  10 , in another exemplary embodiment of the invention. The passage  14  of the pipe wall  12  can have a first passage portion  13  and a second passage portion  15 . The first passage portion  13  can have a smaller diameter or a smaller width than the diameter or width of the second passage portion  15 . The first passage portion  13  can be sized and shaped so the sensor  30 , on the radially inward side of the collar  38 , can fit in the first passage portion  13 . For instance, if the sensor  30 , on the radially inward side of the collar  38  is cylindrical, then the first passage portion can also be cylindrical, sized slightly larger than the sensor  30  on the radially inward side of the collar  38 . 
         [0025]    The second passage portion  15  can be sized and shaped so the collar  38  can fit in the second passage portion  15  and abut or rest against a shoulder  17  that connects between the first passage portion  13  and the second passage portion  15 . The collar  38 , for instance, can be approximately 0.75 inches (19.05 mm) or 0.875 inches (22.225 mm) in diameter. Therefore, the outer diameter of the shoulder  17  can also be approximately between 0.75 inches (19.05 mm) or 0.875 inches (22.225 mm) in diameter, or be slightly larger by an amount sufficient to allow the collar to fit in the second passage portion  15  and permit fastening of the sensor  30  in place. For instance, if the sensor is fastened to the pipe  10  by welding, then the clearance between the collar  38  and the surfaces defining the second passage portion  15  should be limited to an amount acceptable for welding. A spot face  11  can also be added with a larger diameter than the second passage portion  15  to enable room to operate and fasten the sensor  30 . For instance, if the collar  38  has a diameter of approximately 0.75 inches (19.05 mm), then the spot face  11  can have a diameter of approximately 1.0 inches (25.4 mm), which would create a ring-shaped surface of the spot face  11  0.125 inches (3.175 mm) wide. 
         [0026]      FIG. 4  is a partially sectioned side view of a pipe wall  12  with a sensor  30  embedded in the pipe wall  12 , in one embodiment corresponding to  FIG. 3 . The collar  38  can be positioned on the sensor  30 , and the spot face  17  can be positioned between the outer surface  19  and the inner surface  18  of the pipe wall  12  so that the sensor tip  33  can be positioned as desirable, either flush with the inner surface  18  of the pipe wall  12 , extended into the pipe  10  beyond the pipe wall  12  (e.g. toward the center axis of the pipe  10 ), or recessed into the pipe wall  12  (e.g. radially outward from the center axis of the pipe  10 ). Positioning the sensor tip  33  approximately flush with the inner surface  18  of the pipe wall  12  can reduce or prevent any impact the sensor  30  can otherwise have on the flow conditions of the fluid in the pipe  10 . 
         [0027]    The collar  38  can also be approximately flush with the outer surface  19  of the pipe wall  12 , recessed into the pipe wall  12  (e.g. toward the center axis of the pipe  10 ), or extended out of the pipe wall  12  (radially outward from the center axis of the pipe  10 ). Once the sensor  30  is positioned, with the collar  38  abutting, resting, or being pressed against the shoulder  17 , the collar can be fastened in place by such as but not limited to welding at the joint  50  between the collar  38  and the pipe wall  10 . Welding can include but is not limited to electron beam welding and laser welding. The joint  50  can make a seal that can withstand high pressures, including pressures in excess of 10,000 psi (68,947,573 Pa), 15,000 psi (103,421,359 Pa), or 20,000 psi (137,895,146 Pa), and beyond. Positioning the collar  38  so the collar  38  is approximately flush or slightly recessed might allow easier welding. 
         [0028]    The total pipe area required to install a sensor in this fashion can be only slightly larger than the sensor  30  (e.g. 0.5 inches (12.7 mm) larger). Resultantly, less material is used and more room around the pipe  10  is available to install other sensors  30 , if desirable. Sensors  30  can be positioned at multiple points circumferentially around the pipe  10 , or in multiple points along the longitude of the pipe  10 , to map pipe, fluid, and/or flow characteristics three dimensionally. 
         [0029]    A housing  60  can be placed over the sensor  30  and attached to the pipe  10  to protect the sensor  30  and any electronic components. The housing  60  can be fastened to the pipe  10  and the housing  60  can seal out water, other fluids, contaminants, or destructive agents. 
         [0030]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.