JP6258550B1 - Ultrasonic flow meter - Google Patents

Abstract

An ultrasonic transmission / reception unit is adjusted and can be easily attached to a pipeline. An inlet line and an outlet line are arranged in a so-called crank shape with respect to a straight line. Wall surfaces 12c and 13c with which the piezoelectric element 22 abuts via the front plate 24 are formed on the straight pipe 11 from the outside. Yes. The two ultrasonic transmission / reception units 20 have the same shape, and a synthetic resin cover portion 21 having a front portion opened and a rear portion closed, and a piezoelectric element 22 provided in the cover portion 21 for transmitting and receiving an ultrasonic beam, and The cover portion 21 is composed of a front plate 24 having the open side closed and a piezoelectric element 22a disposed on the back surface, and a cable portion 23 connected to the piezoelectric element 22c. The ultrasonic transmission / reception unit 20 in which the output of the internal piezoelectric element is adjusted is arranged on both sides of the pipe line part 10 and connected by screws. [Selection] Figure 3

Description

  The present invention relates to an ultrasonic flowmeter that is used in various industrial fields and measures a fluid flow rate in a pipe.

  In an ultrasonic flow meter, for example, piezoelectric elements that transmit and receive ultrasonic beams are fixed to both ends of a crank-type pipe section, and from one end to the other end of the pipe section through which fluid flows by these piezoelectric elements. The time during which the ultrasonic beam propagates from the other end to the other end is measured, and the flow velocity of the fluid flowing through the pipeline is measured from the difference in propagation time.

  The above-described crank-type pipe section is generally made of synthetic resin and requires a straight pipe section, an inlet pipe section, an outlet pipe section, and piezoelectric element attachment sections on both sides of the straight pipe section. Since this pipe portion has a complicated structure, it is difficult to mold by one injection molding, and it is manufactured by dividing into several parts and combining them together.

  As shown in FIG. 6, in such a conventional ultrasonic flow meter, the fluid to be measured passes through the inlet pipe 1, the straight pipe part 2, and the outlet pipe line 3 in a crank shape, and the straight pipe part 2. Is measured based on the propagation speed of the ultrasonic beam. Piezoelectric elements 4a and 4b are attached to both sides of the straight pipe portion 2, and ultrasonic beams are alternately transmitted and received in the straight pipe portion 2 by the piezoelectric elements 4a and 4b.

  The piezoelectric elements 4a and 4b are housed in cylindrical portions 5a and 5b formed integrally with the inlet pipe line 1 and the outlet pipe line 3, and are attached to the inner walls 6a and 6b on both sides of the straight pipe portion 2 to be piezoelectric. Lead wires 7a and 7b are connected to the elements 4a and 4b. In order to protect the piezoelectric elements 4a and 4b, cap nut-like covers 8a and 8b are screwed together from the outside of the cylindrical portions 5a and 5b.

  In the above-described conventional example, the cover 8a and 8b are structurally attached by screwing so as to surround the cylindrical portions 5a and 5b that accommodate the piezoelectric elements 4a and 4b, so that the volume of the cover 8 is increased. Furthermore, since the lead wires 7a and 7b are drawn out in the direction of the extension line of the straight pipe portion 2, there is a problem that the installation location of the ultrasonic flowmeter is limited.

  Further, the conventional ultrasonic flowmeter has a problem that the assembly work such as soldering of the lead wires 7a and 7b after the piezoelectric elements 4a and 4b are incorporated in the cylindrical portions 5a and 5b becomes complicated. Further, when a piezoelectric element or the like fails during use, it is not possible to simply replace the piezoelectric element or the like on site.

  In addition, since the ultrasonic flowmeter used in the semiconductor manufacturing facility handles a corrosive fluid, it is necessary to use a corrosion-resistant resin such as a fluororesin for the pipe line portion. However, the corrosion resistant resin is more expensive than general synthetic resin materials such as polyethylene, polypropylene, etc. For example, the cylindrical portions 5a and 5b that are not in contact with liquid are also made of a corrosion resistant resin so as to be integrated with the pipe line portion. It must be used and the manufacturing cost is high.

  Similarly, since the covers 8a and 8b attached to the cylindrical portions 5a and 5b have a screwed structure, it is preferable to use the same material as the cylindrical portions 5a and 5b in consideration of the expansion coefficient. If a corrosion resistant resin is used for the road portion, the materials of the covers 8a and 8b are also expensive.

Japanese Patent No. 4991963

The ultrasonic flow meter of Patent Document 1 is by the inventor of the present invention . To solve the problems of the conventional ultrasonic flowmeter described above, Oite that can be easily mounted ultrasonic transmitting and receiving units on opposite sides of the straight pipe portion, the present invention is an improved invention of US Pat.

  An object of the present invention is to eliminate the above-described problems of the conventional example, and to assemble and adjust the ultrasonic transmission / reception unit separately from the pipe line part, and to install the ultrasonic wave unit on the pipe part and use it as it is. To provide a total.

  In order to achieve the above object, an ultrasonic flowmeter according to the present invention includes a cover part having a front part opened and a rear part closed, a piezoelectric element arranged in the cover part for transmitting and receiving an ultrasonic beam, and the piezoelectric element A cable portion connected to the cover portion and drawn outward from the cover portion, and a front plate that closes the front portion of the cover portion and has the piezoelectric element disposed on the back surface, the piezoelectric element being a back surface of the front plate The ultrasonic transmission / reception unit whose transmission / reception performance is adjusted by pressing and the inside of the cover part is hermetically sealed is detachably attached to the wall surfaces on both sides of the straight pipe line of the pipe line for flowing fluid to the crank type, The ultrasonic beam is transmitted / received from the transmission / reception surface of the piezoelectric element to the straight pipe line through the front plate, and the flow rate of the fluid flowing through the pipe part is measured based on the propagation speed of the ultrasonic beam. With features That.

  According to the ultrasonic flow meter of the present invention, separate adjusted ultrasonic transmission / reception units can be easily mounted on both sides of the straight pipe.

It is a disassembled perspective view of the ultrasonic type flow meter of an Example. It is a perspective view of an ultrasonic flowmeter. It is sectional drawing of an ultrasonic flowmeter. It is an expanded sectional view of an ultrasonic transceiver unit. It is a perspective view of the process of mounting | wearing an ultrasonic transmission / reception unit to a pipe line part. It is sectional drawing of the ultrasonic type flow meter of a prior art example.

  The present invention will be described in detail based on the embodiment shown in FIGS.

  1 is an exploded perspective view of the ultrasonic flowmeter of the embodiment, FIG. 2 is a perspective view in an assembled state, FIG. 3 is a cross-sectional view, FIG. 4 is an enlarged cross-sectional view of an ultrasonic transmission / reception unit, and FIG. It is a perspective view.

  The ultrasonic flow meter of the present embodiment is composed of a conduit portion 10 through which a fluid mainly flows and a pair of ultrasonic transmission / reception units 20 attached to both sides of the conduit portion 10.

  The pipe line part 10 is connected to the straight pipe line 11 and one end of the straight pipe line 11 in an L shape by heat welding or the like, and the inlet pipe line 12 into which the fluid flows into the straight pipe line 11 from a right angle direction. And an outlet pipe 13 that is connected to the other end of the straight pipe 11 in an L shape and discharges fluid from the straight pipe 11 in a direction perpendicular to the straight pipe 11. The pipe line 13 is arranged in a so-called crank shape with respect to the straight pipe line 11.

  The pipe section 10 is made of, for example, a corrosion-resistant resin such as PTFE or PFA, and the straight pipe 11, the inlet pipe 12, and the outlet pipe 13 that are individually molded by injection molding or the like are joined by heat welding or the like. . In addition, it becomes possible to confirm the flow of fluid visually by employ | adopting a transparent body for the pipe line part 10. FIG.

  The inlet pipe 12 and the outlet pipe 13 have an inner diameter of 4 mm, for example, and the straight pipe 11 also has an inner diameter of 4 mm. In addition, the internal diameter of the both ends of the straight pipe line 11 is expanded in a taper shape so that it may go to the main-body parts 12a and 13a of the inlet pipe line 12 and the outlet pipe line 13, and it is made not to produce flow-path resistance.

  The inlet pipe 12 and the outlet pipe 13 use the same members, and have large internal volumes 12a, 13a, and pipes connected to the upstream and downstream sides of the main bodies 12a, 13a. It consists of parts 12b and 13b. In addition, fluid pipes are connected to the tips of the tube parts 12b and 13b, respectively.

  The main body portions 12a and 13a on both sides of the straight pipe path 11 are formed with opposing wall surfaces 12c and 13c with which the piezoelectric elements abut from the outside, and the piezoelectric elements are present outside these wall surfaces 12c and 13c. The ultrasonic transmission / reception units 20 are detachably mounted. A pair of screw insertion holes 12d and 13d and a pair of guide receiving portions 12e in which the guide pieces of the ultrasonic transmission / reception unit 20 are in contact with each other along the axial direction of the straight pipe path 11 on the outer peripheral portions of the main body portions 12a and 13a. , 13e are provided.

  The two ultrasonic transmission / reception units 20 have the same shape, and are made of a synthetic resin cover portion 21 made of inexpensive and hard FRP, a piezoelectric element portion 22 fixed in the cover portion 21, and connected to the piezoelectric element portion 22. The cable portion 23 is drawn from a part of the cover portion 21 to the outer flow rate calculation measurement portion.

  The cover part 21 is substantially cylindrical, the front part is opened, and the rear part is closed. The cover portion 21 has a storage portion 21a for accommodating the piezoelectric element portion 22 and tips of two screws 31 and 32 inserted through the screw insertion holes 12d and 12d of the inlet conduit 12 and the outlet conduit 13, respectively. A pair of screw holes 21b to be screwed are provided.

  In addition, when the cover portion 21 is attached to the inlet conduit 12 and the outlet conduit 13, a pair of guide pieces 21c having a guide function for the guide receiving portions 12e and 13e are provided on the outer side of the cover portion 21 on the main body portions 12a and 13a. It is provided for. A small hole 21d communicating with the storage portion 21a is formed behind the cover portion 21. Further, on the rear side of the cover portion 21, a cylindrical cable lead portion 21 e that extends parallel to the surface direction of the piezoelectric element 22 a and extends upward is provided.

  A waterproof bush 23a is inserted through the cable portion 23 so that water does not enter the housing portion 21a from the cable lead-out portion 21e. In the embodiment, the cable lead-out portion 21e is provided upward, but may be formed downward or sideward.

  The piezoelectric element portion 22 in the storage portion 21a is fitted and held with a piezoelectric element 22a that transmits and receives an ultrasonic beam and the piezoelectric element 22a, and cannot rotate and move back and forth with respect to the storage portion 21a. Screwed into the holding portion 22b, the lead wire 22c connected to the piezoelectric element 22a and drawn out from the hole provided in the holding portion 22b, and the screw hole provided in the center of the holding portion 22b, and pressed the piezoelectric element 22a For example, the adjusting screw 22d is made of synthetic resin.

  The piezoelectric element 22a has a thin disk shape, and an acoustic matching plate 22e having the same shape is attached to the surface of the piezoelectric element 22a as necessary. The piezoelectric element 22a is held by the holding portion 22b with the acoustic matching plate 22e facing forward. Has been.

  The front portion of the cover portion 21 is closed by a synthetic resin front plate 24. The front plate 24 is made of a synthetic resin plate made of FRP or the like capable of propagating ultrasonic waves, has a cup-like short cylindrical shape with one end closed, and an open end is pushed into the cover portion 21. An acoustic matching plate 22e and a piezoelectric element 22a are disposed on the back surface of the part. Further, the front plate 24 is fixed so as not to come out by being fitted to the holding portion 22b, and an O-ring 25 is disposed on the outer periphery of the cylindrical portion of the front plate 24, so that the front wall 24 and the front wall of the cover portion 21 are in front of each other. From the outer periphery of the face plate 24, the liquid is prevented from entering the storage portion 21 a.

  When the ultrasonic transmission / reception unit 20 is mounted, an O-ring 26 is interposed between the main body portions 12a, 13a and the cover portion 21, and has a waterproof function to prevent water from entering between them. Yes.

  A support 33 can be attached to the straight pipe 11 to support the load of the ultrasonic flowmeter.

  When assembling the ultrasonic transmission / reception unit 20, the lead wire 22c connected to the piezoelectric element 22a is drawn into the storage portion 21a from the opening of the cover portion 21, and the lead wire 22c is drawn into the cable portion 23 drawn from the cable lead-out portion 21e. For example, solder connection. Next, the holding portion 22b to which the adjusting screw 22d is attached is inserted into the storage portion 21a, and the holding portion 22b is fixed in the storage portion 21a so that it cannot rotate and cannot move back and forth by a fixing mechanism (not shown).

  Next, the piezoelectric element 22a integrated with the acoustic matching plate 22e is pushed in and brought into contact with the tip of the adjusting screw 22d to determine the pushing position. Further, the front plate 24 is pushed into the cover portion 21 together with the O-ring 25, and the front plate 24 is fixed so as not to move back and forth by the holding portion 22b. In this state, the acoustic matching plate 22e and the piezoelectric element 22a are arranged so as to overlap the back surface of the front plate 24.

  In the ultrasonic transmission / reception unit 20 assembled in this way, the cable part 23 is connected to the flow rate calculation measurement part, and transmission / reception adjustment of the piezoelectric element 22a is performed. The ultrasonic transmission / reception unit 20 is attached to a schematic pipe section filled with a fluid equivalent to the fluid to be measured through grease or the like, and one piezoelectric element 22a is connected to the straight pipe section. The transmission / reception performance of the piezoelectric element 22a is adjusted while alternately transmitting / receiving ultrasonic beams by the piezoelectric elements arranged on the opposite sides of the pipe.

  In this adjustment, a driver is inserted through the small hole 21d of the cover portion 21 and the adjusting screw 22d is rotated with respect to the holding portion 22b, pressing the piezoelectric element 22a forward from the back side, and adjusting the pressing force on the front plate 24. Do. Thereby, the transmission / reception performance of the piezoelectric element 22a output via the cable part 23 can be set to a predetermined value.

  The ultrasonic transmission / reception unit 20 that has finished adjusting the transmission / reception performance of the piezoelectric element 22a is filled with silicon resin 27 or the like from the small hole 21d into the accommodating portion 21a to fix the internal components and to ensure electrical insulation. . Further, the small hole 21 d is sealed by filling the silicon resin 27.

  When the ultrasonic transmission / reception unit 20 assembled in this way is mounted on both sides of the duct portion 10, a sheet shape is used so that ultrasonic waves can be easily transmitted between the front plate 24 and the wall surfaces 12c and 13c. The screws 31 and 32 are inserted into the screw insertion holes 12d and 13d, respectively, with a silicon gel or grease medium interposed therebetween. Further, by screwing and fixing the screws 31 and 32 into the screw hole 21b, the ultrasonic transmission / reception unit 20 is connected and integrated on both sides of the pipe line portion 10.

  As a result, the ultrasonic transmission / reception unit 20 is mounted and integrated on both sides of the straight pipe 11, and the cover portion 21 and the wall surfaces 12 c and 13 c are blocked by the O-ring 26 so that grease or the like does not leak. To do.

  The assembled ultrasonic flowmeter is a supersonic wave that is alternately transmitted / received by a pair of piezoelectric elements 22a by a flow measurement calculation unit that flows the fluid to be measured through the conduit 10 and is connected to the piezoelectric element 22a via the cable part 23. The propagation speed of the acoustic beam between the wall surfaces 12c and 13c in the straight pipe 11 can be measured, and the flow velocity of the fluid, that is, the fluid flow rate can be measured.

  In the present embodiment, the ultrasonic transmission / reception unit 20 that has been adjusted in advance can be used immediately by mounting on both sides of the straight pipe 11. However, if there is time allowance, it is of course possible to adjust the actual pipeline section 10.

  The assembled ultrasonic transmission / reception unit 20 is stored or transported in a state in which the transmission / reception performance of the piezoelectric element 22a is adjusted. However, the O-ring 25 and the waterproof bushing 23a further infiltrate water from the small hole 21d. Therefore, the adjusted performance is maintained as it is without the risk of water entering the inside.

  In addition, when measuring blood flow with an ultrasonic flowmeter in cardiac surgery or the like, the flowmeter is often replaced and disposable for each patient in order to prevent infection and the like. In this case, it is economical to dispose of a piezoelectric element or the like that does not come into contact with blood. Therefore, only the pipe part 10 through which blood is circulated is used, and the ultrasonic flowmeter 20 is not necessarily disposable by repeatedly mounting the ultrasonic transmission / reception unit 20 on the new pipe part 10. .

DESCRIPTION OF SYMBOLS 10 Pipe part 11 Straight pipe 12 Inlet pipe 12a, 13a Main body part 12b, 13b Pipe body part 12c, 13c Wall surface 13 Outlet pipe 20 Ultrasonic transmission / reception unit 21 Cover part 21a Storage part 21d Small hole 22 Piezoelectric element part 22a Piezoelectric element 22c Lead wire 22e Acoustic matching plate 23 Cable portion 24 Front plate 25, 26 O-ring 27 Silicon resin 31, 32 Screw

Claims (7)

  A cover part with the front part opened and the rear part closed; a piezoelectric element disposed in the cover part for transmitting and receiving an ultrasonic beam; a cable part connected to the piezoelectric element and drawn out from the cover part; A front plate that closes the front portion of the cover portion and has the piezoelectric element disposed on the back surface thereof, and the transmission and reception performance is adjusted by pressing the piezoelectric element against the back surface of the front plate so that the inside of the cover portion is sealed. The ultrasonic transmission / reception unit is removably attached to the wall surfaces on both sides of the straight pipe line of the pipe part that allows fluid to flow into the crank mold, and is connected to the inside of the straight pipe line from the transmission / reception surface of the piezoelectric element via the front plate. The ultrasonic flowmeter is characterized in that the flow rate of the fluid flowing through the conduit is measured based on the propagation speed of the ultrasonic beam.   The ultrasonic flowmeter according to claim 1, wherein the front plate is made of a material that transmits ultrasonic waves. The flexible material for propagating ultrasonic waves is interposed between the front plate and the wall surface of the straight pipe line when the ultrasonic transmission / reception unit is attached to the straight pipe line. The ultrasonic flowmeter according to 1 or 2.
  The ultrasonic flow meter according to any one of claims 1 to 3, wherein the inside of the cover part is sealed by interposing a waterproof member between the cover part and the front plate.   5. The cable assembly according to claim 1, wherein the cable portion is drawn outward from the cover portion in parallel with a surface direction of the piezoelectric element provided in the ultrasonic transmission / reception unit. Ultrasonic flow meter.   The ultrasonic wave according to any one of claims 1 to 5, wherein the cover part is provided with a guide piece having a guide function with respect to the pipe line part when mounted on the straight pipe line. Type flow meter.   The ultrasonic flowmeter according to any one of claims 1 to 6, wherein the ultrasonic transmission / reception unit is connected to the pipe line portion by a screw when mounted on the straight pipe line.

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