Patent Publication Number: US-2016238420-A1

Title: Electromagnetic flowmeter

Description:
FIELD 
     Embodiments of the present invention relate to an electromagnetic flowmeter. 
     BACKGROUND 
     Conventionally, electromagnetic flowmeters are known, in which flanges are attached to a pipe by full-circled welding. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japan Patent Application Laid-open No. 2009-288026 
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     It is desirable that such electromagnetic flowmeters having different specifications including mount hole positions on the flanges can commonly use a part of their elements. 
     Means for Solving Problem 
     An electromagnetic flowmeter of an embodiment, for an example, comprises a pipe, a detector and a flange. A fluid to be measured flows through the pipe. The detector detects the fluid to be measured. The flange includes a plurality of members. The members are integrated with the pipe with a fastener while surrounding an outer periphery of the pipe. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of an example of an electromagnetic flowmeter according to a first embodiment. 
         FIG. 2  is a cross-sectional view of  FIG. 1  along the II-II line. 
         FIG. 3  is a cross-sectional view of  FIG. 2  along the line. 
         FIG. 4  is a planar view (a partial cross-sectional view) of an example of an electromagnetic flowmeter according to a second embodiment. 
         FIG. 5  is a planar view (a partial cross-sectional view) of an example of an electromagnetic flowmeter according to a third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments will be described below with reference to the accompanying drawings. The following embodiments include same or like constituent elements. Hence, in the following, the same or like constituent elements are given the common reference numerals, and a redundant explanation is omitted. Moreover, the following embodiments will merely illustrate examples of configurations (technical features) as well as action and effects resulting from the configurations. The present invention can also be implemented by different configurations other than the configurations disclosed in the following embodiments, and can achieve various effects (including consequential effects) obtained by the fundamental configuration (technical features). 
     First Embodiment 
     In a first embodiment, as illustrated in  FIG. 1 , an electromagnetic flowmeter  1  includes a detector  2  and a converter  3  (a display device or an electronic device). The detector  2  includes a pipe  7  having an internal flow channel  7   a  and includes a detecting element  14  (see  FIG. 2 ) that detects a fluid to be measured which flows through the flow channel  7   a . The detecting element  14  includes a pair of electrodes  9 ,  9  to contact with the fluid to be measured (in  FIG. 2 , only a single electrode  9  is illustrated), and includes exciting coils  8  (coil units) housed in a case  20  of the pipe  7 . The line connecting the pair of electrodes  9 ,  9  is substantially orthogonal to the axial center of the pipe  7  (a measurement pipe  4 ) (hereinafter, simply referred to as the axial center). The exciting coils  8  generate a magnetic field in the direction orthogonal to the line connecting the pair of electrodes  9 ,  9  and orthogonal to the axial center. The converter  3  includes a housing  10  accommodating a display  12 , and a controller (not illustrated). The converter  3  is fixed on the detector  2  via a coupler  13 . The coupler  13  includes a wiring (a harness or a cord) via which the converter  3  (the controller) and the detector  2  are electrically connected (the detecting element  14 ). 
     In the electromagnetic flowmeter  1 , a magnetic field is generated inside the pipe  7  by the exciting coils  8 . A flow of the fluid to be measured orthogonal to the magnetic field causes generation of an electromotive force in the direction orthogonal to the magnetic field and the fluid to be measured. The electromotive force from the fluid to be measured is detected by the pair of electrodes  9 ,  9 . Then, the pair of electrodes  9 ,  9  transmits a detection signal according to the electromotive force to the controller of the converter  3 . The controller calculates (detects) a magnitude (value) of the electromotive force from the detection signal. Moreover, the controller calculates a flow rate from the calculated magnitude of the electromotive force and displays the flow rate on the display  12  (a display screen  12   a ). 
     The display  12  includes the display screen  12   a  and is supported in the housing  10  in such a manner that the display screen  12   a  is visible. In the first embodiment, as an example, the display device  12  is contained in the housing  10  and is covered with a panel  11 . Moreover, the panel  11  has a transparent (for example, colorless and transparent) cover  11   a  (a transmissive member, a translucent member, or a window) disposed thereon. The display screen  12   a  of the display device  12  is viewed through the cover  11   a . The display  12  is a liquid crystal display (LCD), for example. 
     As an example, as illustrated in  FIGS. 1 and 2 , the pipe  7  includes the measurement pipe  4  (pipe), flanges  5 , and a lining  6 . The pipe  7  can be coupled with another pipe (a pipe to be measured, not illustrated) through which the fluid to be measured flows. The detecting element  14  and the controller detect the flow rate of the fluid to be measured from the another pipe into the pipe body  7 . 
     As an example, the measurement pipe  4  includes a base  41  (a tubular portion) and projections  42  (flanges). The base  41  has a tubular shape (in the first embodiment, as an example, a cylindrical shape) along the axis (axial center) of the pipe  7 . The projections  42  are provided at both axial ends  41   c ,  41   c  of the base  41  (see  FIG. 2 ), and project in a direction intersecting with (in the first embodiment, as an example, orthogonal to) the axial direction. Moreover, the projections  42  are configured to expand as a flat plate and a ring (in the first embodiment, as an example, annular) in the orthogonal direction to the axial direction (radial direction). 
     The base  41  has an outer face  41   a  (outer periphery, outside face, face opposite the flow channel  7   a , or a first face) and an inner face  41   b  (inner periphery, inside face, face closer to the flow channel  7   a , or a second face). The case  20  (the exciting coils  8 ) and the flanges  5  are provided on the outer face  41   a  of the measurement pipe  4  (the base  41 ) while the pair of electrodes  9 ,  9  and the lining  6  are provided on the inner face  41   b  of the measurement pipe  4  (the base  41 ). Each projection  42  includes an end face  42   a  (face opposite the flange or a first face) and an end face  42   b  (face closer to the flange  5  or a second face). As an example, the measurement pipe  4  can be made from a nonmagnetic material such as SUS (stainless steel). 
     As an example, the case  20  includes a pair of end plates  15 ,  15  and covers  16 . The pair of end plates  15 ,  15  are provided with a spacing along the axis of the measurement pipe  4  (the base  41 ) and are oriented in a direction intersecting with (in the first embodiment, as an example, orthogonal to) the axial direction. For example, the end plates  15  can be secured (joined) onto the outer face  41   a  of the base  41  by welding. The covers  16  are disposed lateral to the exciting coils  8 , opposing the base  41 , and cover the exciting coils  8 . The covers  16  can be secured (joined) on the outer peripheries of the end plates  15  by welding. 
     The lining  6  includes, as an example, a tubular portion  6   a  (a first portion) and flare portions  6   b  (second portions). The tubular portion  6   a  is a tubular (in the first embodiment, as an example, cylindrical) along the inner face  41   b  of the base  41 , and covers the inner face  41   b . The inner face of the tubular portion  6   a  forms the flow channel  7   a . The flare portions  6   b  are circular (in the first embodiment, as an example, plate-like and annular) along the end faces  42   a  of the projections  42 , and cover the end faces  42   a . The flare portions  6   b  are provided at both axial ends of the tubular portion  6   a  and project in a direction intersecting with (in the first embodiment, as an example, orthogonal to) the axial direction. Thus, the flare portions  6   b  cover the respective projections  42  from outside axially. 
     Moreover, the flare portions  6   b  each include an end face  6   c  which opposes the end face  42   a  of the corresponding projection  42  and forms the outer face of the pipe  7 . As an example, the lining  6  extends across the base  41  and the projections  42 . The tubular portion  6   a  and the flare portions  6   b  of the lining  6  protect the inner face  41   b  of the base  41  and the ends face  42   a  of the projections  42 . The lining  6  can be made from a synthetic resin material such as fluorine contained resin. 
     As an example, the flanges  5  have a circular shape (in the first embodiment, as an example, an annular shape) along the outer face  41   a  of the base  41 . The flanges  5  are provided at both axial ends  41   c  of the measurement pipe  4  (the base  41 ). The pair of flanges  5 ,  5  may be simply referred to as the flange  5  when they do not need to be discriminated. 
     The flange  5  has an end face  5   a  (a face or a joint face) with which an object to join (a flange of another pipe coupled with the pipe  7 ) is overlapped or which opposes the object. Moreover, the flange  5  includes a plurality of holes  5   b  (mount holes) that pass through the flange  5  in the axial direction. As illustrated in  FIG. 3 , the holes  5   b  are provided at a constant interval (at any interval) along the circumference of the flange  5  at a plurality of (any number of) positions. Fasteners (such as bolts, not illustrated) are inserted into the holes  5   b  for joining the pipe  7  with the object (the flange of another pipe coupled with the pipe  7 ). As an example, the flange  5  can be made from a metallic material such as SUS (stainless steel). 
     Moreover, each flange  5  includes a plurality of members. More particularly, as illustrated in  FIGS. 1 and 3 , as an example, the flange  5  includes a first member  5 A and a second member  5 B which are two equal divisions of the flange  5  along the plane passing on the central axis of the pipe  7 . Thus, the first member  5 A and the second member  5 B have the same shape. 
     As illustrated in  FIG. 3 , the first member  5 A as well as the second member  5 B each include a base  51 , a pair of protrusions  52  and  53 , and end faces  54  and  55 . The base  51  has an arc-like shape along the outer face  41   a  of the measurement pipe  4  (the base  41 ). The protrusion  52  is provided on one circumferential end  51   a  of the base  51  and protrudes outward radially from the base  51 . The protrusion  53  is provided on the other circumferential end  51   b  of the base  51  and protrudes outward radially from the base  51 . The end face  54  and the end face  55  are overlapped on (face) each other. The end face  54  and the end face  55  extend across the base  51  and the pair of protrusions  52  and  53 . The protrusion  52  and the protrusion  53  include holes  52   a  and  52   b  (mount holes) and holes  53   a  and  53   b  (mount holes), respectively. The holes  52   a  and  52   b  pass through the protrusion  52  in a direction intersecting with (in the first embodiment, as an example, orthogonal to) the protrusion  52 . The holes  53   a  and  53   b  pass through the protrusion  53  in a direction intersecting with (in the first embodiment, as an example, orthogonal to) the protrusion  53 . 
     The first member  5 A and the second member  5 B are integrated with each other with fasteners  18  (in the first embodiment, as an example, bolts  18   a  and nuts  18   b ). More particularly, the first member  5 A and the second member  5 B are overlaid on the end faces  42   b  of the projections  42  and are positioned and partially fixed to the base  41  and the projections  42  by spot welding (Wp represents the spot welding positions, see  FIG. 2 ). Then, the first member  5 A and the second member  5 B are integrated with each other by inserting the bolts  18   a  into the holes  52   a  and  52   b  of the protrusion  52  and the holes  53   a  and  53   b  of the protrusion  53  and fastening the nuts  18   b . In the first embodiment, as illustrated in  FIG. 3 , there is a certain gap  30  between the first member  5 A and the second member  5 B, extending in the direction connecting the protrusion  52  and the protrusion  53  while the end face  54  and the end face  55  are overlapped. Hence, according to the first embodiment, as an example, manufacturing variations (dimensional variations) can be eliminated. Therefore, as an example, as compared to no gap  30  provided, the binding force of the fasteners  18  can be reliably exerted, leading to more firmly integrating the measurement pipe  4  and the flanges  5  (the first members  5 A and the second members  5 B). 
     Moreover, in the first embodiment, as illustrated in  FIG. 2 , at the time of attaching the flange  5  to the measurement pipe  4 , the first member  5 A and the second member  5 B are positioned and partially fixed to the base  41  and the projections  42  by spot welding (at the welding positions Wp). Hence, according to the first embodiment, as an example, the first member  5 A and the second member  5 B can be attached to the measurement pipe  4  by a simpler, smoother, or more accurate work. 
     As described above, in the first embodiment, as an example, the flanges  5  each include the first member  5 A and the second member  5 B that are integrated with the measurement pipe  4  with the fasteners  18 . Hence, according to the first embodiment, as an example, as compared to the conventional configuration in which the flanges  5  are attached to the measurement pipe  4  by full-circled welding, the flanges  5  can be more easily attached to the measurement pipe  4 . Moreover, according to the first embodiment, as an example, a plurality of pipes  7  (electromagnetic flowmeters  1 ) having different specifications can be obtained by joining a single measurement pipe  4  with the flanges  5  having different specifications. That is, the measurement pipe  4  can be commonly used for the plurality of pipes  7  (electromagnetic flowmeters  1 ) having different specifications. This can accordingly reduce the manufacturing costs of the electromagnetic flowmeters  1 , as an example. Furthermore, as compared to the flanges attached to the measurement pipe  4  by full-circled welding, thermal effects on the lining  6  can be easily reduced. 
     In the first embodiment, as an example, each flange  5  (the first member  5 A and the second member  5 B) is attached to the measurement pipe  4  with the fasteners  18 . Because of this, the flanges  5  can be advantageously attached to the measurement pipe  4  (the base  41 ) after the molding of the lining  6 . Conventionally, for attaching the flanges  5  by full-circled welding, with the thermal effects on the lining  6  taken into account, the flanges  5  need to be attached to the measurement pipe  4  (the base  41 ) before the molding of the lining  6 . In this case, for example, if no pipes  7  matching the standard (size) of the object to join (the flanges of another pipe coupled with the pipe  7 ) are available, a new pipe  7  has to be prepared by integrating as the measurement pipe  4  with the flanges  5 . This likely results in a relatively longer manufacturing lead time (standby period). In this regard, according to the first embodiment, the flanges  5  can be attached to the measurement pipe  4  (the base  41 ) after the lining  6  is formed on the measurement pipe  4 . This can advantageously reduce the manufacturing lead time and decrease the number of products in progress in stock. Hence, according to the first embodiment, as an example, the manufacturing time and costs for the electromagnetic flowmeter  1  can be easily reduced. 
     Moreover, in the first embodiment, as an example, the measurement pipe  4  includes the base  41  and the projections  42  provided at the ends  41   c  of the base  41 , and the flanges  5  and the projections  42  are overlaid in the axial direction. Hence, according to the first embodiment, as an example the first member  5 A and the second member  5 B can be inhibited from moving along the axis of the measurement pipe  4  by the projections  42 . Thereby, as an example, the first member  5 A and the second member  5 B can be attached to the measurement pipe  4  by a simpler, smoother, or more accurate work. Moreover, as an example, the flanges  5  (the integrated first member  5 A and second member  5 B) can be prevented from coming off from the measurement pipe  4 . 
     Furthermore, in the first embodiment, as an example, the lining  6  includes the tubular portion  6   a  (a first portion, which covers the inner face  41   b  of the base  41 , and the flare portions  6   b  (second portions) which cover the projections  42  from axially outside. Hence, according to the first embodiment, as an example, the sealing between the flanges  5  and the object to join (the flanges of another pipe coupled with the pipe  7 ) can be easily enhanced by the flare portions  6   b.    
     The first embodiment has exemplified the wetted electromagnetic flowmeter  1  in which the pair of electrodes  9  contacts with the fluid to be measured. However, the electromagnetic flowmeter should not be limited thereto, and can be of a non-wetted type in which the pair of electrodes  9  does not contact with the fluid to be measured. 
     Moreover, in the first embodiment, although the first member  5 A and the second member  5 B are positioned with respect to the measurement pipe  4  by spot welding, the spot welding is not always necessary. Unlike full-circled welding, spot welding is partial welding, therefore, it will thermally affect the lining  6  less even if the lining  6  is already provided on the measurement pipe  4 . 
     Second Embodiment 
     An electromagnetic flowmeter illustrated in  FIG. 4  according to a second embodiment has the same configuration to the electromagnetic flowmeter  1  according to the first embodiment. Hence, the second embodiment can also achieve the same results (effects) based on the same configuration. 
     However, in the second embodiment, as an example, as illustrated in  FIG. 4 , covers  16 A extend along the axis of the measurement pipe  4  to connect to the flanges  5 . More particularly, in the second embodiment, as an example, the covers  16 A are secured with the flanges  5  (the first members  5 A and the second members  5 B) by full-circled welding (Wf represents the full-circled welding positions). Hence, according to the second embodiment, as an example, at the time of joining the object (the flanges of another pipe coupled with the pipe  7 ) and the flanges  5 , the load applied on the flanges  5  can be transferred to the covers  16 A. Accordingly, as an example, it is able to suppress an increase in the stress on the flanges  5  due to the join with the object (the flanges of another pipe coupled with the pipe  7 ). Moreover, since the full-circled welding positions Wf are separated from the measurement pipe  4 , it is advantageous that the lining  6  is subjected to less thermal effects. Furthermore, owing to the full-circled welding, water or foreign particles are prevented from entering the gaps between the covers  16 A and the flanges  5 . 
     Third Embodiment 
     An electromagnetic flowmeter illustrated in  FIG. 5  according to a third embodiment has the same configuration to the second embodiment. Hence, the third embodiment can also achieve the same results (effects) based on the same configuration. 
     However, in the third embodiment, as an example, as illustrated in  FIG. 5 , the covers  16 A are integrated with the flanges  5 . More particularly, in the third embodiment, as an example, the pipe  7  includes a first member  23  and a second member  24 . The first member  23  is made of the first members  5 A of the flanges  5  and a first cover member  26  of the cover  16 A integrated with each other. Similarly, the second member  24  is made of the second members  5 B of the flanges  5  and a second cover member  27  of the cover  16 A integrated with each other. Herein, for example, the first member  23  and the second member  24  are cast elements (die-cast elements) made by casting (die-casting) a metallic material. Moreover, the first member  23  and the second member  24  are two equal divisions of the flanges  5  and the covers  16 A along the plane passing on the central axis of the pipe  7 . Thus, the first member  23  and the second member  24  have the same shape. Furthermore, in the third embodiment, the first member  5 A and the second member  5 B are joined with the fasteners  18 , and the first cover member  26  and the second cover member  27  are joined with fasteners  21  (in the third embodiment, as an example, bolts  21   a  and nuts  21   b ) to integrate the first member  23  with the second member  24 . Hence, according to the third embodiment, as an example, since the covers  16 A and the flanges  5  are integrated with each other, welding of the cover s  16 A and the flanges  5  is omissible during the assembly. This may accordingly lead to reducing the manufacturing lead time. Moreover, as an example, the integrated covers  16 A and flanges  5  can contribute to improving the rigidity and strength of the pipe  7 . 
     While certain embodiments of the invention have been described, the embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms, and various omissions, substitutions, combinations and changes may be made without departing from the spirit of the inventions. The above embodiments are included in the scope and spirit of the invention and in the accompanying claims and their equivalents. Moreover, regarding the constituent elements, the specifications (structure, type, direction, shape, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be suitably modified. For example, an inclusion (a cushioning member or a sealing member) can be placed in the gap between the first member and the second member or between the first cover member and the second cover member.