CN110274640B - Electromagnetic flowmeter - Google Patents
Electromagnetic flowmeter Download PDFInfo
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- CN110274640B CN110274640B CN201910183835.8A CN201910183835A CN110274640B CN 110274640 B CN110274640 B CN 110274640B CN 201910183835 A CN201910183835 A CN 201910183835A CN 110274640 B CN110274640 B CN 110274640B
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- Prior art keywords
- measurement tube
- hole
- elastic member
- joint
- flat surface
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
- G01F1/58—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
- G01F1/58—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters
- G01F1/588—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters combined constructions of electrodes, coils or magnetic circuits, accessories therefor
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Volume Flow (AREA)
Abstract
The electromagnetic flowmeter of the present invention is configured to accurately perform flow rate measurement and sealing performance inspection, and to prevent damage to a measurement tube. The disclosed device is provided with: a measuring tube (13); a housing (2); a through hole (45) into which an end of the measurement tube is inserted; and a joint (41) having a 1 st flat surface (49) (flat surface) facing the distal end surface (13b) of the measurement tube. The disclosed device is provided with: an O-ring (52) (sealing member) provided between the outer peripheral surface (13a) (outer surface) of the measurement tube and the hole wall surface (46a) of the 1 st hole (46); and an annular elastic member (53) provided between the distal end surface of the measurement tube and the 1 st flat surface. The elastic member is formed with a pressure guide path (55) between the distal end surface and the 1 st flat surface of the measurement tube, the pressure guide path communicating an internal space (56) through which a fluid flows and a space (57), the space (57) being defined by the outer peripheral surface of the measurement tube, the hole wall surface of the 1 st hole, the 1 st flat surface, and the O-ring.
Description
Technical Field
The present invention relates to an electromagnetic flowmeter including a joint that forms a fluid passage in cooperation with a measurement tube.
Background
As a conventional electromagnetic flowmeter, for example, there is an electromagnetic flowmeter including a joint for connecting an upstream pipe and a downstream pipe as described in patent documents 1 and 2. The joint includes a cylindrical portion forming a fluid passage and a flange portion fixed to a case of the electromagnetic flowmeter so as to project radially outward from the cylindrical portion. A circular hole into which the distal end portion of the measurement tube is inserted and connected is formed in one end portion of the cylindrical portion, and a sealing member for sealing between the circular hole and the outer peripheral surface of the measurement tube is provided.
The other end of the cylindrical portion is provided with a female screw into which the pipe is screwed and an octagonal projection for use with a tool. The housing of the electromagnetic flowmeter is formed of metal or plastic. The measuring tube is formed of ceramic or plastic and the joint is formed of metal.
However, in the electromagnetic flowmeter having the structure in which the measurement pipe is connected to the joint, the tightness of the connection portion between the measurement pipe and the joint is checked after the assembly is completed. The inspection is performed by filling a fluid passage formed by the measurement tube and the joint with an inspection fluid and applying pressure to the fluid passage. By performing this inspection, the pressure of the fluid is applied from the fluid passage side to the O-ring provided between the measurement tube and the circular hole of the cylindrical portion. If the sealing performance of the O-ring does not reach the predetermined standard, the fluid leaks, and therefore it can be determined that the sealing performance is low.
Documents of the prior art
Patent document
Patent document 1: japanese patent No. 5887683
Patent document 2: japanese patent No. 6250580
Disclosure of Invention
[ problems to be solved by the invention ]
In an electromagnetic flowmeter in which a measurement tube is connected to a pipe via a joint, the measurement tube may be damaged due to an excessive bending load or a compressive load applied to the measurement tube.
This bending load is often applied to the measuring tube when connecting the electromagnetic flowmeter to the pipe. When the electromagnetic flowmeter is connected to a pipe, the pipe is usually screwed into a joint in a state where the joint is fixed.
However, when an operator screws a pipe into the joint in a state in which the housing is fixed instead of the joint, a load in a torsional direction and a load in a bending direction are applied from the joint to the housing. When a load is applied like this, the housing is elastically deformed between the fixed portion of the housing and the joint, and the joint is displaced accordingly. At this time, when the tip end of the measurement tube abuts on the joint, the measurement tube is displaced integrally with the joint and is broken.
Such deformation of the casing may occur even when the upstream pipe and the downstream pipe are axially misaligned. When the electromagnetic flowmeter is installed between the upstream-side pipe and the downstream-side pipe where the axis deviation occurs in this manner, a bending load is applied to the housing from the pair of joints on both sides of the housing to which the pipes are connected, and the housing is elastically deformed. Even in such a case, if the amount of deformation of the case increases, the measurement tube cannot withstand the deformation and is damaged.
On the other hand, the reason why an excessive compressive load is applied to the measurement tube is that thermal expansion occurs in the pipe, various components (casing, joint, measurement tube, etc.). The pipe is elongated due to thermal expansion caused by the temperature of the fluid or the temperature rise around the electromagnetic flowmeter. The upstream-side pipe and the downstream-side pipe are respectively elongated, so that a compressive load is applied to the measurement tube. Further, since the thermal expansion coefficients of the respective members are different from member to member, a compressive load due to a difference in thermal expansion may be applied to the measurement tube. When such a compressive load is excessively large, the measurement tube cannot undergo deformation and is broken.
In order to prevent such damage to the measurement tube, it is conceivable to insert an annular rubber member between the distal end surface of the measurement tube and the joint and to bring the distal end of the measurement tube into contact with the joint via the rubber member. With this configuration, the joint can be displaced relative to the measurement tube in accordance with the degree of elastic deformation of the rubber member while holding the measurement tube by the joint.
However, when the rubber member is provided between the measurement tube and the joint in this manner, the rubber member functions as a fluid seal member, which causes a problem. That is, the fluid becomes unable to reach the O-ring provided between the measurement tube and the circular hole of the joint, and the sealability of the O-ring cannot be checked.
To eliminate such a problem, it is conceivable to form the rubber member in a C shape instead of a ring shape so that the fluid can reach the O-ring. However, since the shape of the C-shaped rubber member is unstable, a part of the distal end side may be deformed to protrude into the measurement pipe. When a part of the rubber member protrudes into the measurement tube in this manner, the protruding portion disturbs the flow of the measurement fluid flowing in the measurement tube, and the flow rate cannot be accurately measured in the electromagnetic flowmeter.
The invention aims to prevent the damage of a measuring tube while adopting a structure which can accurately measure the flow and check the tightness.
[ means for solving problems ]
In order to achieve the object, an electromagnetic flowmeter according to the present invention includes: a measurement tube through which a fluid to be measured flows; a housing that houses the measurement tube and has a connection port at a position facing an end of the housed measurement tube; a cylindrical joint having a through hole into which an end of the measurement tube is inserted and a flat surface facing a distal end surface of the measurement tube inserted into the through hole, the joint being inserted into the connection port of the housing and fixed to the housing; a sealing member provided between an outer surface of the measurement tube and a hole wall surface of the through hole; and an annular elastic member that is provided between the tip end surface of the measurement tube and the flat surface, the elastic member forming a pressure guide path between the tip end surface of the measurement tube and the flat surface, the pressure guide path communicating an internal space defined by the measurement tube and the joint, through which the fluid flows, and a space defined by an outer surface of the measurement tube, a hole wall surface of the through hole, the flat surface, and the sealing member.
In the electromagnetic flowmeter of the present invention, the elastic member may be formed of a gasket, and a 1 st contact portion of the gasket contacting the distal end surface of the measurement tube and a 2 nd contact portion of the gasket contacting the flat surface of the joint may be alternately arranged in a circumferential direction.
In the electromagnetic flowmeter of the present invention, the elastic member may be formed of a disc spring.
In the electromagnetic flowmeter of the present invention, the disc spring may have a notch at least one of an outer peripheral edge and an inner peripheral edge thereof.
In the electromagnetic flowmeter of the present invention, the elastic member may be formed by a compression coil spring that is located on a shaft coaxial with the measurement tube.
In the electromagnetic flowmeter of the present invention, the elastic member may be formed of a metal material.
[ Effect of the invention ]
In the present invention, the load transmitted from the joint to the measurement tube is relaxed by the elastic deformation of the elastic member. Further, since the fluid in the through hole reaches the seal member through the pressure guide path, the seal performance of the seal member can be accurately checked. Further, the elastic member is formed in a ring shape and does not protrude into the through hole, so that the flow rate can be accurately measured.
Therefore, according to the present invention, it is possible to provide an electromagnetic flowmeter having a configuration capable of accurately performing flow rate measurement and sealing performance inspection and preventing damage to a measurement tube.
Drawings
Fig. 1 is a sectional view of a case portion of an electromagnetic flow meter according to embodiment 1.
Fig. 2 is a plan view of the housing portion.
Fig. 3 is an exploded perspective view of the case side of the electromagnetic flowmeter.
Fig. 4 is an enlarged cross-sectional view showing one end side of the housing.
Fig. 5 is a sectional view showing an enlarged main portion.
Fig. 6 is a front view of the elastic member.
Fig. 7 is a perspective view of the elastic member.
Fig. 8 is a sectional view of a case portion of the electromagnetic flow meter according to embodiment 2.
Fig. 9 is a sectional view showing a modification of the elastic member.
Fig. 10 is a front view showing a modification of the elastic member.
Fig. 11 is a front view showing a modification of the elastic member.
Fig. 12 is a sectional view showing a modification of the elastic member.
Detailed Description
(embodiment 1)
Next, an embodiment of an electromagnetic flowmeter according to the present invention will be described in detail with reference to fig. 1 to 7.
The electromagnetic flowmeter 1 shown in fig. 1 is a capacitance type, and is configured using a box-shaped case 2 and a cover 3, the case 2 being positioned on the lower side of fig. 1, and the cover 3 closing an opening 2a of the case 2. Fig. 1 is a sectional view taken along line I-I in fig. 2 as a top view of a housing portion.
As shown in fig. 2 and 3, the case 2 is formed in a rectangular shape when viewed from the opening side (upper side in fig. 3), and has a rectangular bottom wall 4, the 1 st and 2 nd side walls 5, 6 extending in the longitudinal direction of the bottom wall 4, and the 3 rd and 4 th side walls 7, 8 extending in the width direction of the bottom wall 4. The 1 st sidewall 5 and the 2 nd sidewall 6 are formed parallel to each other. The 3 rd and 4 th sidewalls 7 and 8 are formed parallel to each other. The housing 2 of this embodiment is formed into a predetermined shape using plastic as an insulating material. Therefore, the bottom wall 4, the 1 st and 2 nd side walls 5 and 6, and the 3 rd and 4 th side walls 7 and 8 are integrally formed.
Hereinafter, for convenience, the direction in which the bottom wall 4 and the opening 2a are aligned will be described as the vertical direction, the longitudinal direction of the bottom wall 4 will be described as the horizontal direction, and the width direction of the bottom wall 4 will be described as the front-rear direction. As shown in fig. 1, the 3 rd side wall 7 is located on the left side of the housing 2, and the 4 th side wall 8 is located on the right side of the housing 2. Further, as shown in fig. 2, the 1 st side wall 5 is located on the front side of the housing 2, and the 2 nd side wall 6 is located on the rear side of the housing 2. Further, the bottom wall 4 is located at the lower end of the case 2, and the opening 2a is located at the upper end of the case 2.
A yoke 11 is attached to the bottom wall 4 of the housing 2. The excitation coil 12 is attached to each of the front end and the rear end of the yoke 11. By exciting the exciting coil 12, a magnetic field is generated between the front end portion and the rear end portion of the yoke 11. As shown in fig. 1, the yoke 11 is placed on the opening 2a side at a predetermined height from the bottom wall 4 so that the excitation coil 12 has the same height as a measuring tube 13 described later. Therefore, the magnetic field generated from the excitation coil 12 traverses the measurement tube 13 in the front-rear direction.
A 1 st printed circuit board 14 and a 2 nd printed circuit board 15 are mounted on the 1 st side wall 5 and the 2 nd side wall 6 of the case 2, respectively. The 1 st printed board 14 is located in the vicinity of the 3 rd side wall 7 in a state of extending in the front-rear direction and the up-down direction, and the 2 nd printed board 15 is located in the vicinity of the 4 th side wall 8 in a state of extending in the front-rear direction and the up-down direction.
The 1 st printed circuit board 14 and the 2 nd printed circuit board 15 are each formed in a rectangular plate shape. A circular through hole 16 is formed in the center of each of the 1 st printed circuit board 14 and the 2 nd printed circuit board 15. The measuring tube 13 is inserted through the through hole 16.
The measurement tube 13 is a tube through which a fluid to be measured, not shown, flows, is formed in a cylindrical shape from ceramic or plastic, and is press-fitted into the through holes 16 of the 1 st printed circuit board 14 and the 2 nd printed circuit board 15. The fluid of the measurement object flows from the left side to the right side in fig. 1. The material of the measuring tube 13 may be changed as appropriate as long as it is an electrically insulating material, and may be plastic, for example. The 1 st printed circuit board 14 and the 2 nd printed circuit board 15 are provided at both ends of the measurement tube 13. Further, although not shown, a shield cover for covering the measurement tube 13 may be provided between the 1 st printed circuit board 14 and the 2 nd printed circuit board 15.
The measuring tube 13 is provided with a 1 st electrode 21 and a 2 nd electrode 22 for measuring a flow rate, and a 3 rd electrode 23 for measuring a conductivity. The 1 st electrode 21 and the 2 nd electrode 22 are disposed at positions sandwiching the measurement tube 13 from the vertical direction, and are connected to a flow rate measurement circuit 24 provided on the 2 nd printed circuit board 15.
The 1 st electrode 21 to the 3 rd electrode 23 are made of a film-like metal material (e.g., copper foil) and are bonded to the measurement tube 13 with an adhesive.
The 1 st electrode 21 and the 2 nd electrode 22 are arranged so as to face each other in a direction perpendicular to a magnetic field generated from the excitation coil 12.
The 3 rd electrode 23 is formed in a shape covering a part of the left side of the measuring tube 13 over the entire circumference, and is connected to a circuit 25 for measuring conductivity provided on the 1 st printed circuit board 14.
The 1 st printed circuit board 14 and the 2 nd printed circuit board 15 are fixed to both end portions of the measurement tube 13, and both end portions in the front-rear direction are attached to the 1 st side wall 5 and the 2 nd side wall 6 of the housing 2. By thus mounting the 1 st printed circuit board 14 and the 2 nd printed circuit board 15 to the case 2, the 1 st printed circuit board 14 and the 2 nd printed circuit board 15 and the measurement tube 13 are housed in the case 2.
The mounting structure for mounting the 1 st printed circuit board 14 and the 2 nd printed circuit board 15 to the housing 2 is as follows: both ends in the front-rear direction of the 1 st printed circuit board 14 and the 2 nd printed circuit board 15 are inserted into the guide grooves 26 provided in the 1 st side wall 5 and the 2 nd side wall 6 of the housing 2. The guide groove 26 is formed between a pair of projections 27, 27 extending in the up-down direction. The mounting structure is constructed in the following manner: the 1 st printed board 14 and the 2 nd printed board 15 can move in the front-rear direction, the left-right direction, and the up-down direction with respect to the housing 2 against frictional resistance.
As shown in fig. 1, connection ports 31 and 32 are formed in the 3 rd side wall 7 and the 4 th side wall 8 of the case 2 at positions facing the end portions of the measurement tube 13. These connection ports 31 and 32 are formed to penetrate the 3 rd and 4 th side walls 7 and 8, respectively, in the left-right direction. The cylindrical portions 42 of the joints 41 described later are inserted into the connection ports 31 and 32, respectively.
The joints 41 are used to connect pipes, not shown, and are fixed to both ends of the housing 2 in the left-right direction.
The joint 41 located at the left end of the housing 2 and the joint 41 located at the right end of the housing 2 have the same structure. The joint 41 of this embodiment is composed of a cylindrical portion 42 and a flange portion 44, the cylindrical portion 42 is formed in a cylindrical shape and forms a fluid passage 43 in cooperation with the measurement tube 13, and the flange portion 44 protrudes from the cylindrical portion 42 in the up-down direction and the front-rear direction. The joint 41 is made of a metal material having corrosion resistance against the fluid to be measured.
As shown in fig. 4, the hollow portion of the cylindrical portion 42 is formed by a passage hole 45. The passage hole 45 of this embodiment is formed by a 1 st hole 46, a screw hole 47, and a 2 nd hole 48, the 1 st hole 46 being open to the inside of the case 2 and into which the measurement tube 13 is inserted, the screw hole 47 being open to the outside of the case 2, and the 2 nd hole 48 communicating the 1 st hole 46 with the screw hole 47. The opening shapes of the 1 st hole 46 and the 2 nd hole 48 are circular. The threaded hole 47 has an internal thread 47a for pipe connection formed therein.
The diameter of the 2 nd hole 48 is smaller than the diameters of the 1 st hole 46 and the threaded hole 47, and is substantially equal to the inner diameter of the measuring tube 13. A 1 st flat surface 49 perpendicular to the axis C of the cylindrical portion 42 is formed at a boundary portion between the 1 st hole 46 and the 2 nd hole 48. The 1 st flat surface 49 is formed in an annular shape when viewed from the axial direction of the cylindrical portion 42.
As shown in FIG. 5, the 1 st hole 46 has a diameter slightly larger than the outer diameter of both ends of the measuring tube 13. Therefore, the measurement tube 13 is fitted in the 1 st hole 46 in a clearance fit state. A gap d is formed between the outer peripheral surface 13a of the measurement tube 13 and the hole wall surface 46a of the 1 st hole 46.
An annular groove 51 is formed in the hole wall surface 46a of the 1 st hole 46. An O-ring 52 is fitted in the annular groove 51. The O-ring 52 seals between the outer peripheral surface 13a of the measurement tube 13 and the 1 st hole 46 in a liquid-tight manner. In this embodiment, the O-ring 52 corresponds to a "seal member" in the present invention.
The measurement tube 13 is inserted into the 1 st hole 46, and the 1 st annular flat surface 49 faces the distal end surface 13b of the measurement tube 13. An annular elastic member 53 is provided between the 1 st flat surface 49 and the distal end surface 13b of the measurement tube 13. The outer diameter of the elastic member 53 of this embodiment is the outer diameter fitted in the 1 st hole 46. The inner diameter of the elastic member 53 is substantially equal to the inner diameter of the measurement tube 13.
The elastic member 53 of this embodiment is formed of a wave washer 54, and the wave washer 54 is formed of a metal material. The metal material forming the wave washer 54 is a material having corrosion resistance to the fluid to be measured.
In this embodiment, the wave washer 54 corresponds to the "washer" of the invention described in claim 2.
As shown in fig. 5, the wave washer 54 has a 1 st contact portion 54a that contacts the distal end surface 13b of the measurement tube 13 and a 2 nd contact portion 54b that contacts the 1 st flat surface 49 of the cylindrical portion 42, and is sandwiched between the distal end surface 13b and the 1 st flat surface 49 and slightly compressed. As shown in fig. 6 and 7, the 1 st contact portion 54a and the 2 nd contact portion 54b are alternately arranged in the circumferential direction of the wave washer 54. The shape of the wave washer 54 is not limited to the shape shown in the embodiment. For example, the wave washer 54 may be formed by winding a corrugated bare wire into a coil shape.
As shown in fig. 5, the wave washer 54 forms a pressure guide path 55 between the distal end surface 13b of the measurement tube 13 and the 1 st flat surface 49 of the cylindrical portion 42. The pressure guide path 55 communicates an internal space 56 through which a fluid to be measured flows and a space 57 leading to the O-ring 52. The internal space 56 is a space defined by the measurement tube 13 and the joint 41, through which a fluid to be measured flows.
The space 57 is a space defined by the outer peripheral surface 13a of the measurement pipe 13, the hole wall surface 46a of the 1 st hole 46, the 1 st flat surface 49 of the cylindrical portion 42, and the O-ring 52.
As shown in fig. 3, the flange portion 44 of the joint 41 is formed in a rectangular plate shape and is fixed to the 3 rd and 4 th side walls 7 and 8 of the case 2 by fixing bolts not shown. As shown in fig. 3, the portion of the cylindrical portion 42 protruding outside the housing 2 has an octagonal engaging projection 42a so that a tool (not shown) can be used.
As shown in fig. 4, a 2 nd flat surface 61 orthogonal to the axis C of the cylindrical portion 42 is formed at the distal end of the cylindrical portion 42 located inside the housing 2.
The 2 nd flat surface 61 is formed in an annular shape when viewed from the axial direction of the cylindrical portion 42. In a state where the contact 41 is mounted on the housing 2, the 2 nd flat surface 61 faces the first main surfaces 14a and 15a of the 1 st printed circuit board 14 and the 2 nd printed circuit board 15.
Connecting members 62 formed of wave washers are provided between the 2 nd flat surface 61 and the 1 st printed circuit board 14 and the 2 nd printed circuit board 15, respectively. The connecting member 62 is formed in a ring shape having a hollow portion 63 into which the measuring tube 13 can be inserted.
In order to assemble the electromagnetic flowmeter 1 configured as described above, first, the assembly including the yoke 11 and the exciting coil 12 is attached to the case 2, and then, the assembly including the measuring tube 13, the 1 st printed circuit board 14, and the 2 nd printed circuit board 15 is attached. Then, the end of the measurement tube 13 is inserted into the hollow 63 of the connecting member 62, and the connecting member 62 is held at both ends of the measurement tube 13. Thereafter, the cylindrical portions 42 of the joints 41 are inserted into the connection ports 31 and 32 of the housing 2, and the pair of joints 41 are attached to both end portions of the housing 2 in the left-right direction. Before the joint 41 is attached to the housing 2, the O-ring 52 and the elastic member 53 are previously installed inside the cylindrical portion 42.
The flange 44 is fastened to the 3 rd and 4 th side walls 7 and 8 of the case 2 by fixing bolts (not shown), whereby the joint 41 is fixed to the case 2. By fixing the joint 41 to the case 2 in this manner, the elastic member 53 in the cylindrical portion 42 is sandwiched between the 1 st flat surface 49 in the cylindrical portion 42 and the distal end surface 13b of the measurement tube 13, and the connecting member 62 is sandwiched between the 2 nd flat surface 61 located at the distal end of the cylindrical portion 42 and the 1 st printed circuit board 14 and the 2 nd printed circuit board 15.
In this assembling process, the elastic member 53 is slightly elastically deformed and compressed in the left-right direction of the housing 2.
After the assembly operation of the electromagnetic flowmeter 1 is completed, the sealing performance of the O-ring 52 is checked. This inspection is performed by connecting an inspection device (not shown) to each of the two connectors 41 and filling the fluid channel 43 with a liquid for inspection. The liquid passes from the internal space 56 between the distal end surface 13b of the measurement tube 13 and the 1 st flat surface 49 of the cylindrical portion 42, through the pressure guide path 55 and the space 57 defined by the outer peripheral surface 13a of the measurement tube 13, the hole wall surface 46a of the 1 st hole 46, the 1 st flat surface 49 of the cylindrical portion 42, and the O-ring 52, and reaches the O-ring 52. Therefore, the pressure in the fluid passage 43 is transmitted to the O-ring 52 via the liquid, and the tightness can be correctly checked.
When the electromagnetic flowmeter 1 is connected to a pipe (not shown), the pipe is screwed into the joint 41 with the joint 41 fixed. At this time, if the pipe is erroneously screwed into the joint 41 in a state where the case 2 is fixed, the joint 41 may be displaced so as to be inclined with respect to the measurement tube 13 in accordance with the elastic deformation of the case 2. When the joint 41 is displaced relative to the measurement tube 13 in this manner, the elastic member 53 is elastically deformed by being sandwiched between the distal end surface 13b of the measurement tube 13 and the 1 st flat surface 49 of the joint 41. Therefore, the elastic member 53 absorbs the displacement of the joint 41 to relax the load applied to the measurement tube 13.
When the pipe (not shown) on the upstream side to which the electromagnetic flow meter 1 is attached and the pipe (not shown) on the downstream side are axially misaligned, a bending load is applied to the measurement pipe 13 from the joint 41 when the electromagnetic flow meter 1 is attached to these pipes. However, in this case, the elastic member 53 is also elastically deformed, and the bending load applied to the measurement tube 13 from the joint 41 is relaxed.
Further, even in a case where a compressive load is applied to the measurement tube 13 due to thermal expansion of the case 2, the measurement tube 13, the joint 41, the pipe, and the like, the compressive load is relaxed by the elastic member 53 being elastically deformed.
The elastic member 53 is formed in a ring shape, and therefore a part thereof does not protrude into the through hole 45. Therefore, the elastic member 53 does not interfere with the flow rate measurement of the electromagnetic flowmeter 1.
Therefore, according to this embodiment, it is possible to provide an electromagnetic flowmeter that has a configuration capable of accurately measuring a flow rate and checking sealing performance, and that can prevent the measurement tube 13 from being damaged.
In this embodiment, since the distal end surface 13b of the measurement tube 13 can be estimated by the elastic member 53, the measurement tube 1 can be elastically supported by the elastic force of the elastic member 53. Therefore, by setting the elastic force of the elastic member 53 to an appropriate elastic force with respect to the measurement tube 13, the measurement tube 13 can be fixed with an appropriate load.
The elastic member 53 of this embodiment is formed of a wave washer 54 made of metal, and the 1 st contact portion 54a of the wave washer 54 contacting the distal end surface 13b of the measurement tube 13 and the 2 nd contact portion 54b of the 1 st flat surface 49 of the contact joint 41 are alternately arranged in the circumferential direction.
Therefore, according to this embodiment, the finished wave washer can be used as the elastic member 53, and therefore the present invention can be realized at low cost.
(embodiment 2)
In the above embodiment, an example of the electromagnetic flowmeter 1 in which the present invention is applied to the measurement tube 13 supported by the case 2 via the pair of printed boards 14 and 15 is shown. However, the present invention is not limited to this, and can be applied to an electromagnetic flowmeter in which a measurement tube is supported without using a printed circuit board, as shown in fig. 8. In fig. 8, the same or equivalent members as those described with reference to fig. 1 to 7 are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.
In the electromagnetic flowmeter 71 shown in fig. 8, both end portions of the measuring tube 13 are inserted into the 1 st hole 46 of the joint 41 in a clearance fit state. Annular shoulder portions 72 are provided at both end portions of the measurement tube 13. The O-ring 52 is attached to the distal end side of the measurement pipe 13 via the shoulder portion 72. The O-ring 52 seals between the outer peripheral surface 13a of the measurement tube 13 and the 1 st hole 46.
An elastic member 53 is provided between the distal end surface 13b of the measurement tube 13 and the 1 st flat surface 49 of the joint 41. The elastic member 53 is formed of a wave washer 54 similar to the washer used in embodiment 1.
The measurement tube 13 is supported by the pair of joints 41 in a state where both end portions are fitted in the cylindrical portions 42 of the joints 41 and pressed from both sides by the elastic force of the elastic member 53.
The 1 st electrode 21 and the 2 nd electrode 22 provided at the center of the measuring tube 13 are connected to the flow rate measuring circuit 73 located on the opening side of the case 2 by lead wires, not shown.
Even in the configuration in which the measurement tube 13 is supported only by the pair of joints 41, the displacement of the joints 41 with respect to the measurement tube 13 is absorbed by the elastic deformation of the elastic member 53 in the same manner as in the case of embodiment 1. Therefore, in this embodiment, it is possible to provide an electromagnetic flowmeter that can prevent the breakage of the measuring tube 13 while employing a configuration that can accurately perform flow rate measurement and tightness inspection.
(modification of elastic Member)
The elastic member 53 is not limited to the wave washer 54, and may be modified as appropriate.
The elastic member 53 can be formed as shown in fig. 9 to 12, for example.
In fig. 9 to 12, the same or equivalent members as those described with reference to fig. 1 to 8 are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.
The elastic member 5 shown in fig. 9 is formed of a metal disc spring 81. The metal material forming the disc spring 81 is a material having corrosion resistance to the fluid to be measured. The outer edge 81a and the inner edge 81b of the disc spring 81 are formed in a circular shape. Although not shown, minute irregularities are formed in the outer peripheral edge 81a and the inner peripheral edge 81b within a tolerance range set when the disc spring 81 is formed. Even if the disc spring 81 is in close contact with the distal end surface 13b of the measuring tube 13 and the 1 st flat surface 49 of the cylindrical portion 42, the disc spring 81 cannot seal between the distal end surface 13b and the 1 st flat surface 49. That is, in the disc spring 81 shown in fig. 9, minute concave portions formed on the outer peripheral edge 81a and the inner peripheral edge 81b constitute a part of the pressure guide path 55.
The elastic member 53 shown in fig. 10 is formed of a metal disc spring 83 having a plurality of notches 82 in its outer peripheral portion. In the disc spring 83 shown in fig. 10, the notch 82 in the outer peripheral portion constitutes a part of the pressure guide path.
The elastic member 53 shown in fig. 11 is formed of a metal disc spring 85 having a plurality of notches 84 in an inner peripheral portion thereof. In a disc spring 85 shown in fig. 11, a notch 84 in an inner peripheral portion constitutes a part of a pressure guide path. The metal material forming the disc springs 81 and 85 is a material having corrosion resistance to the fluid to be measured.
With the configuration shown in fig. 9 to 11, the finished disc springs 81, 83, and 85 can be used as the elastic member 53, and therefore, the cost of the electromagnetic flowmeter can be reduced by using the inexpensive elastic member 53.
The elastic member 53 shown in fig. 12 is formed of a metallic compression coil spring 86, and the compression coil spring 86 is positioned on a shaft coaxial with the measurement tube 13. The metal material forming the compression coil spring 86 is a material having corrosion resistance against the fluid to be measured.
In the compression coil spring 86 shown in fig. 12, a pressure guide path 55 is formed between the bare wires. With this configuration, the finished compression coil spring 76 can be used as the elastic member 53, and therefore, the cost of the electromagnetic flowmeter can be reduced by using the inexpensive elastic member 53.
The elastic member 53 described in each of the above embodiments is formed of a metal material that is corrosive to the fluid to be measured. Therefore, even if the electromagnetic flow meters 1 and 71 are used for a long time, the performance of the elastic member 53 is not lowered, and therefore, when the electromagnetic flow meters 1 and 71 are attached to and detached from a pipe (not shown) for maintenance after a long time use, the measurement pipe 13 is not damaged.
Description of the symbols
1. 71 … an electromagnetic flow meter for measuring the flow rate of a fluid,
2 … shell, 13 … measuring tube,
13b … at the top end face thereof,
the connectors 31 and 32 … are connected,
the 41 … connection terminal is connected with the connector,
42 … a cylindrical portion, the cylindrical portion,
45 … through-hole is formed in the through-hole,
46a … are formed on the wall of the hole,
49 … flat face No. 1 (flat face),
52 … O-ring (sealing member),
the resilient member of 53 … is provided with,
54 … wave washer, the wave washer is,
54a … at the 1 st contact point,
54b … at the 2 nd contact position,
55 … the pressure-guiding path is provided,
56 … the space inside the container body,
the space of the air inlet pipe is 57 …,
81. 83, 85 … are formed by a disc spring,
82. the incision of the 84 … is made,
86 … compress the helical spring and,
d … gap.
Claims (6)
1. An electromagnetic flowmeter, comprising:
a measurement tube through which a fluid to be measured flows;
a housing that houses the measurement tube and has a connection port at a position facing an end of the housed measurement tube;
a cylindrical joint having a through hole into which an end of the measurement tube is inserted and a flat surface facing a distal end surface of the measurement tube inserted into the through hole, the joint being inserted into the connection port of the housing and fixed to the housing;
a sealing member provided between an outer surface of the measurement tube and a hole wall surface of the through hole; and
an annular elastic member provided between the distal end surface of the measurement tube and the flat surface,
the elastic member forms a pressure guide path between the tip end surface of the measurement tube and the flat surface, the pressure guide path communicating an inner space defined by the measurement tube and the joint, through which the fluid flows, and a space defined by an outer surface of the measurement tube, a hole wall surface of the through hole, the flat surface, and the sealing member.
2. An electromagnetic flowmeter according to claim 1,
the elastic member is formed of washers, and the 1 st contact portion of the washer that contacts the tip end face of the measurement tube and the 2 nd contact portion that contacts the flat face of the joint are alternately arranged in the circumferential direction.
3. An electromagnetic flowmeter according to claim 1,
the elastic member is formed of a disc spring.
4. The electromagnetic flow meter according to claim 3,
the disc spring has a notch at least one of an outer peripheral edge and an inner peripheral edge thereof.
5. An electromagnetic flowmeter according to claim 1,
the elastic member is formed of a compression coil spring which is located on a shaft coaxial with the measurement tube.
6. An electromagnetic flow meter according to any of claims 1 to 5,
the elastic member is formed of a metal material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018045408A JP6940437B2 (en) | 2018-03-13 | 2018-03-13 | Electromagnetic flow meter |
| JP2018-045408 | 2018-03-13 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110274640A CN110274640A (en) | 2019-09-24 |
| CN110274640B true CN110274640B (en) | 2020-08-11 |
Family
ID=67959185
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910183835.8A Active CN110274640B (en) | 2018-03-13 | 2019-03-12 | Electromagnetic flowmeter |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP6940437B2 (en) |
| CN (1) | CN110274640B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2021081268A (en) * | 2019-11-18 | 2021-05-27 | アズビル株式会社 | Electromagnetic flowmeter |
| CN113669633B (en) * | 2021-07-30 | 2023-03-14 | 开封科隆流量仪表有限公司 | KLLD type clamp connection type electromagnetic flowmeter |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0554059B1 (en) * | 1992-01-31 | 2002-07-24 | Kabushiki Kaisha Toshiba | Electromagnetic flowmeter |
| JP2916665B2 (en) * | 1994-06-28 | 1999-07-05 | 三菱電線工業株式会社 | connector |
| EP1686602B2 (en) * | 2005-02-01 | 2021-04-07 | ABB Power Grids Switzerland AG | Blast nozzle mounting means for electrical circuit breaker |
| CN101493111B (en) * | 2008-10-22 | 2010-08-11 | 陈炳顺 | Special disk spring gasket and clutch release bearing assembly |
| US9400507B2 (en) * | 2012-09-28 | 2016-07-26 | Emerson Process Management Regulator Technologies, Inc. | Upstream sense for balance port |
| CN103174897B (en) * | 2013-04-08 | 2015-05-20 | 上海沃施园艺股份有限公司 | Hosepipe bypass seal joint |
| JP6250580B2 (en) * | 2015-03-30 | 2017-12-20 | Ckd株式会社 | Electromagnetic flow meter and collective unit |
| CN205424246U (en) * | 2016-03-24 | 2016-08-03 | 绍兴柯桥滨海供水有限公司 | Novel pipeline joint |
-
2018
- 2018-03-13 JP JP2018045408A patent/JP6940437B2/en active Active
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2019
- 2019-03-12 CN CN201910183835.8A patent/CN110274640B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| JP2019158586A (en) | 2019-09-19 |
| CN110274640A (en) | 2019-09-24 |
| JP6940437B2 (en) | 2021-09-29 |
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