JP7056096B2 - Ultrasonic flow measurement structure - Google Patents

Description

The present invention relates to an ultrasonic flow rate measuring structure, and more particularly to an ultrasonic flow rate measuring structure for measuring the flow rate of a fluid flowing in a pipe.

Conventionally, in order to measure the flow rate of various fluids in a pipe, for example, an ultrasonic flow meter disclosed in Patent Document 1 has been proposed. The ultrasonic flow meter of Patent Document 1 is provided with ultrasonic transmission / reception units provided on the outer periphery on the upstream side and the outer periphery on the downstream side of the pipe, respectively, and propagates ultrasonic waves into the fluid to measure the flow velocity of the fluid. .. In the ultrasonic flow meter of Patent Document 1, since the pipe propagating wave propagating through the pipe wall and propagating to the receiver becomes a noise component, a cylindrical ultrasonic absorber is provided on the outer periphery of the pipe to provide energy for the pipe propagating wave. We are trying to attenuate. The ultrasonic absorber has two rubber layers, and the outer rubber layer has a smaller viscoelasticity than the inner rubber layer.

Japanese Unexamined Patent Publication No. 2015-21799

However, in Patent Document 1, although the outer rubber layer suppresses deformation over time due to the weight of the inner rubber layer, the ultrasonic absorber is formed only of rubber, so that the ultrasonic absorber adheres to the pipe. There is room for improvement.

The present invention has been made in view of this point, and one of the objects thereof is to provide an ultrasonic flow rate measuring structure capable of allowing an absorber to be in good contact with a pipe.

One aspect of the ultrasonic flow measurement structure in the present invention is an ultrasonic sensor mounted on the outer periphery of a pipe through which a fluid passes and capable of transmitting and receiving ultrasonic waves, and an ultrasonic sensor provided on the outer periphery of the pipe and transmitted from the ultrasonic sensor. An absorber that absorbs the pipe propagating wave propagating in the pipe, a cover member provided on the outer peripheral side of the absorber, and the pipe between the absorber and the cover member. The cover member includes a maintenance member that maintains close contact between the pipe and the absorber when a force in a direction in contact with the cover member is applied, and the maintenance member is characterized in that it is made of metal.

According to this configuration, since the maintenance member for maintaining the close contact between the pipe and the absorber is provided, when a force is applied to the absorber by the cover member, a gap is generated between the pipe and the absorber, and those are formed. It is possible to suppress the occurrence of unevenness in the close contact state, and it is possible to make the absorber adhere well to the pipe. As a result, the noise component removing action of the absorber can be maintained satisfactorily, and the accuracy of the flow rate measurement can be stabilized.

According to the present invention, since the maintenance member for maintaining the close contact between the pipe and the absorber is provided, the absorbent body can be brought into good contact with the pipe.

It is schematic cross-sectional view of the ultrasonic flow rate measurement structure which concerns on embodiment. It is a side view of the ultrasonic flow rate measurement structure which concerns on embodiment. It is a top view of the ultrasonic flow rate measurement structure which concerns on embodiment.

Here, in the ultrasonic flow measurement of the fluid flowing in the pipe, the vibration propagating in the pipeline wall is propagated from the pipeline wall to the ultrasonic absorber, and the vibration is reduced by the ultrasonic absorber at the propagation destination. That is, it is important to propagate the vibration from the conduit wall to the ultrasonic absorber. Therefore, tungsten or the like is added to the ultrasonic absorber to bring the acoustic impedance of the ultrasonic absorber closer to the pipe, so that the vibration can be easily propagated from the conduit wall to the ultrasonic absorber. On the other hand, since the acoustic impedance of air is significantly different from that of pipes and ultrasonic absorbers, if there is a gap between the conduit wall and the ultrasonic absorber, the vibration propagating through the conduit wall propagates to the ultrasonic absorber. It becomes difficult to do. Therefore, it is required that the pipe and the ultrasonic absorber are evenly adhered to each other without any gap.

However, in Patent Document 1, as described above, there is room for improvement in the adhesion between the piping and the ultrasonic absorber. As a proposal for improving the adhesion, a configuration is conceivable in which a cover member is provided on the outside of the ultrasonic absorber in Patent Document 1, and the ultrasonic absorber is pressed against the outer periphery of the pipe by the cover member.

However, in such a configuration, when the ultrasonic absorber is pressed, the cover member does not deform evenly in the circumferential direction and varies, and the variation causes the ultrasonic absorber to be displaced so as to shift in the circumferential direction. .. For this reason, there is a problem that the contact state between the pipe and the ultrasonic absorber is uneven or a gap is generated between them, and as a result, the damping of the pipe propagating wave by the ultrasonic absorber is insufficient. There is a problem of becoming.

In response to this problem, in the invention according to claim 1, since the maintenance member for maintaining the close contact between the pipe and the absorber is provided, even if the amount of deformation of the cover member varies in the circumferential direction of the pipe, it is in the same direction. It is possible to prevent a part of the absorber from being displaced more than the other parts. As a result, when a force is applied to the absorber by the cover member, it is possible to prevent a gap from being generated between the pipe and the absorber and uneven contact between them, and the absorber is evenly adhered to the pipe. be able to.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following embodiments, and can be appropriately modified and implemented without changing the gist thereof. In the following figures, some configurations may be omitted for convenience of explanation.

FIG. 1 is a schematic cross-sectional view of the ultrasonic flow rate measuring structure according to the embodiment cut along a plane orthogonal to the extending direction of the pipe. FIG. 2 is a side view of the ultrasonic flow rate measuring structure according to the embodiment. As shown in FIGS. 1 and 2, the ultrasonic flow measurement structure 10 includes a first ultrasonic sensor 11 and a second ultrasonic sensor 12 mounted on a pipe P. Further, the ultrasonic flow rate measuring structure 10 includes an absorber 20 provided so as to be in surface contact with the outer peripheral surface of the pipe P, a cover member 30 provided on the outer peripheral side of the absorber 20, and the absorber 20 and a cover member. It is provided with a maintenance member 40 interposed between the 30 and the maintenance member 40. Here, the fluid flowing in the pipe P is a gas such as various gases or a liquid such as water.

The first ultrasonic sensor 11 and the second ultrasonic sensor 12 are provided in contact with and fixed to the outer periphery of the pipe P. The first ultrasonic sensor 11 and the second ultrasonic sensor 12 are provided at different positions in the flow direction of the fluid flowing in the pipe P (indicated by the arrow in FIG. 2), and in the present embodiment, the first ultrasonic wave is provided. A sensor 11 is relatively upstream, and a second ultrasonic sensor 12 is relatively downstream.

The first ultrasonic sensor 11 and the second ultrasonic sensor 12 are provided at positions where ultrasonic waves can be transmitted and received, respectively, and transmit and receive mutual ultrasonic waves. Specifically, the ultrasonic waves transmitted by the first ultrasonic sensor 11 are received by the second ultrasonic sensor 12, and the ultrasonic waves transmitted by the second ultrasonic sensor 12 are received by the first ultrasonic sensor 11. To. In the first ultrasonic sensor 11 and the second ultrasonic sensor 12, ultrasonic waves are propagated in the flow direction of the fluid and the opposite direction, and the flow velocity and the flow rate of the fluid can be calculated by measuring the propagation time thereof. ing.

The absorber 20 is provided so as to cover the outer periphery of the pipe P around the first ultrasonic sensor 11 and the second ultrasonic sensor 12. The absorber 20 has a function of absorbing a pipe propagating wave transmitted from each ultrasonic sensor 11 and 12 and propagating through the pipe P. Specifically, the absorber 20 is formed by mixing particles such as tungsten with a main material such as butyl rubber and silicone that attenuates vibration noise, forming a sheet shape, and attaching the absorber 20 so as to wind around the outer periphery of the pipe P. .. The reason why the particles such as tungsten are mixed is to bring the acoustic impedance of the absorber 20 closer to the acoustic impedance of the pipe P and to improve the effect of absorbing vibration noise.

The cover member 30 is formed of a material different from that of the absorber 20, and is not particularly limited, but is formed by bending a single metal plate member or the like. Examples of the metal include stainless steel having a plate thickness of several millimeters to several millimeters. In the cross-sectional view of FIG. 1, the cover member 30 is formed by being connected to a cover main body 31 having a C-shaped arc shape along the cylindrical shape of the pipe P and both ends of the C-shape of the cover main body 31. 1 A pair of projecting piece portions 32 projecting to the right in the middle are provided.

The pair of projecting piece portions 32 are provided in parallel, and a plurality of (three in the present embodiment) screw members 33 are provided so as to penetrate in their planes. Further, a nut 34 is screwed to the tip end side of each screw member 33, and by screwing the screw member 33 into the nut 34, the pair of protruding piece portions 32 are displaced or deformed in the approaching direction. Due to this displacement or the like, a tensile force is generated on the cover main body 31, and the maintenance member 40 and the absorber 20 can be tightened. On the other hand, by loosening the screw member 33 with respect to the nut 34 from the tightened state, the pair of projecting piece portions 32 are displaced or deformed in the direction away from each other, and the tightening of the maintenance member 40 and the absorber 20 by the cover body 31 is loosened. .. Here, each protruding piece portion 32, the screw member 33, and the nut 34 constitute an adjusting portion 36 that adjusts the contact pressure of the absorber 20 with respect to the pipe P.

The maintenance member 40 is also made of the same metal material as the cover member 30, and is formed in a C-shaped arc shape along the cylindrical shape of the pipe P in the cross-sectional view of FIG. Both ends of the C-shape of the maintenance member 40 are arranged between both ends of the C-shape of the cover main body 31.

Here, openings 20a, 30a, 40a are formed in the absorber 20, the cover member 30, and the maintenance member 40 at the installation positions of the ultrasonic sensors 11 and 12. In other words, the ultrasonic sensors 11 and 12 are received inside the openings 20a, 30a and 40a. The opening 20a of the absorber 20 and the opening 40a of the maintenance member 40 are formed at substantially the same position surrounding the adjacent positions of the ultrasonic sensors 11 and 12 (see FIG. 3).

The opening 30a of the cover member 30 is formed in a shape and size enlarged in the vertical direction in FIG. 3 as compared with the other openings 20a and 40a. A positioning portion 41 is provided on the outer peripheral surface of the maintenance member 40 inside the opening 30a of the cover member 30 so as to protrude from the outer peripheral surface. Positioning portions 41 are provided on both sides of the pipe P in the circumferential direction (vertical direction in FIG. 3) with respect to the ultrasonic sensors 11 and 12, respectively. The positioning portion 41 is not particularly limited, but is a rectangular piece of metal having a thickness of several millimeters, and is fixed to the maintenance member 40 by welding or the like. The positioning portion 41 may be formed by bending the maintenance member 40 around the opening 40a so as to have a thickness of two sheets.

The positioning portion 41 is arranged along the forming edge of the opening 30a so as to fit into the opening 30a of the cover member 30. By fitting the positioning portion 41 into the opening 30a, the relative displacement between the circumference of the opening 30a of the cover member 30 and the circumference of the opening 40a of the maintenance member 40 is restricted, and their relative positions are positioned. As a result, when the cover member 30 is mounted on the outside of the maintenance member 40, the openings 30a and 40a can be easily positioned with each other, and by extension, the maintenance member 40 and the cover member 30 can be easily positioned. Can be done.

In the above configuration, when the absorber 20 is pressed against the pipe P from the illustrated state and brought into close contact with the pipe P, the screw member 33 of the adjusting portion 36 may be screwed in. At this time, in the adjusting portion 36, the protruding piece portions 32 are deformed or displaced in the approaching direction, a tensile force is generated on the cover main body 31, and the inner peripheral surface is reduced in diameter. As a result, the cover member 30 can apply a force in the direction in which the absorber 20 comes into contact with the pipe P via the maintenance member 40. In other words, the cover member 30 presses the maintenance member 40 and the absorber 20 toward the pipe P side, and the adhesion between the absorber 20 and the pipe P can be improved.

Here, in the cover member 30, when the screw member 33 is screwed in, the amount of deformation on the protruding piece portion 32 side is larger than that on the opposite side sandwiching the pipe P. Even if the amount of deformation of the cover member 30 varies in the circumferential direction of the pipe P in this way, the maintenance member 40 is interposed between the cover member 30 and the absorber 20, so that the effect of such variation is affected by the absorber 20. Will not be received. Specifically, it is possible to prevent the absorber 20 from being displaced or deformed so that only the vicinity of the protruding piece portion 32 is displaced, and wrinkles or the like are generated in the absorber 20 between the pipe P and the absorber 20. It is possible to suppress the occurrence of gaps in the space and the unevenness of their close contact state. As a result, the close contact between the pipe P and the absorber 20 can be maintained evenly, and the pipe propagating wave is satisfactorily absorbed by the absorber 20 to stabilize the measurement accuracy by the ultrasonic sensors 11 and 12. Can be planned.

Further, since the strength around the opening 30a of the cover member 30 decreases, when a tensile force is generated on the cover member 30 by screwing the screw member 33, deformation is likely to occur around the opening 30a. However, in the present embodiment, since the positioning portion 41 provided in the maintenance member 40 fits with the opening 30a of the cover member 30, the positioning portion 41 can reinforce the circumference of the opening 30a, and the deformation around the opening 30a can be caused. It can be suppressed. As a result, it is possible to better achieve equalization of the adhesion between the pipe P and the absorber 20, and it is possible to maintain the state well.

Further, the embodiment of the present invention is not limited to the above embodiment, and may be variously modified, replaced, or modified without departing from the spirit of the technical idea of the present invention. Further, if the technical idea of the present invention can be realized in another way by the advancement of the technique or another technique derived from the technique, it may be carried out by the method. Therefore, the scope of claims covers all embodiments that may be included within the scope of the technical idea of the present invention.

In the above embodiment, the case where the cover member 30 and the maintenance member 40 are made of metal is exemplified, but the cover member 30 and the maintenance member 40 may be made of another material such as a hard synthetic resin. However, by forming the cover member 30 and the maintenance member 40 with metal, it is advantageous in that the strength that can withstand the tightening by the adjusting portion 36 and the flexibility that can correspond to the cylindrical shape of the pipe P can be satisfactorily obtained.

Further, the adjusting unit 36 can be changed in various ways as long as the contact pressure of the absorber 20 with respect to the pipe P in the cover member 30 can be adjusted. For example, the strip-shaped body is wound around the cover member 30 and the strip-shaped body is tightened. A buckle or the like that can adjust the force may be provided.

10 Ultrasonic flow measurement structure 11 First ultrasonic sensor (ultrasonic sensor)
12 Second ultrasonic sensor (ultrasonic sensor)
20 Absorber 20a Opening 30 Cover member 30a Opening 36 Adjusting part 40 Maintaining member 40a Opening 41 Positioning part P Piping

Claims (4)

An ultrasonic sensor that is mounted on the outer circumference of a pipe through which fluid passes and can transmit and receive ultrasonic waves,
An absorber provided on the outer periphery of the pipe and absorbing a pipe propagating wave transmitted from the ultrasonic sensor and propagating through the pipe,
A cover member provided on the outer peripheral side of the absorber and
A maintenance member that is interposed between the absorber and the cover member and maintains close contact between the pipe and the absorber when a force in the direction of contacting the pipe is applied to the absorber by the cover member. Equipped with
The maintenance member has an ultrasonic flow rate measuring structure, characterized in that it is made of metal. The absorber, the cover member, and the maintenance member each have an opening for internally receiving the ultrasonic sensor.
The ultrasonic flow rate measuring structure according to claim 1 , wherein the maintenance member is provided with a positioning portion for positioning a relative position between the circumference of the opening of the cover member and the circumference of the opening of the maintenance member. The ultrasonic flow rate measuring structure according to claim 2, wherein the positioning portion is formed so as to protrude from the maintenance member and fit into the opening of the cover member. The ultrasonic flow rate measuring structure according to any one of claims 1 to 3 , wherein the cover member includes an adjusting portion for adjusting the contact pressure of the absorber with respect to the pipe.

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