JP2011033389A - Ultrasonic flowmeter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic flowmeter which can raise work efficiency, in an assembly work for mounting an ultrasonic sensor on a measuring tube. <P>SOLUTION: In the ultrasonic flowmeter 1 having the measuring tube 2 having a channel 9 through which fluid flows, at least one pair of ultrasonic sensors 5, 5 positioned on the upstream side and the downstream side of the channel 9, and arranged on a line tilted with respect to the axis of the measuring tube 2 are disposed, and a flow rate of the fluid is measured by transmitting/receiving an ultrasonic wave between the ultrasonic sensors 5, 5. The ultrasonic sensor 5 is fixed in a sensor case 3, and the sensor case 3 is fixed from a direction orthogonal to the axial direction of the measuring tube 2 onto the measuring tube 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ultrasonic flow meter.

  Conventionally, ultrasonic waves are transmitted and received between a pair of ultrasonic sensors that are attached to the upstream side and the downstream side of a measurement tube through which a gas flows and are inclined with respect to the axis of the measurement tube. An ultrasonic flow meter 101 as shown in FIG. 18 is known as an ultrasonic flow meter for measuring the gas flow rate.

  As shown in FIG. 18, the ultrasonic flowmeter 101 has a measuring tube 102 formed therein with a flow channel 102a through which a gas such as a gas to be measured flows, and the measuring tube 102 includes Socket portions 103 and 103 which are inclined with respect to the shaft center and protrude outward are formed integrally with each other. The pair of socket parts 103 and 103 are arranged so that their axes are positioned on the same straight line, and an ultrasonic sensor 104 is fixed to both the socket parts 103 and 103. The ultrasonic sensor 104 has a side surface formed in a cylindrical shape, and the circumferential surface of the ultrasonic sensor 104 is directly fitted and fixed to the cylindrical socket portion 103.

  In the conventional ultrasonic flowmeter 101, since the socket portion 103 is inclined outwardly from the axis of the measuring tube 102 and is integrally fixed and protrudes, the ultrasonic sensor 104 is placed in the protruded socket portion 103. There is a problem that it is necessary to take a wide working space in the axial direction of the measuring tube 102 when performing the attaching work.

  In addition, since the measuring tube 102 and the socket portion 103 are integrally formed, it is necessary to directly attach the ultrasonic sensor 104 to the socket portion 103, and there is a problem that work efficiency is poor.

  Therefore, an object of the present invention is to provide an ultrasonic flow meter that can solve the above-described problems.

In order to solve the above-mentioned problem, the invention according to claim 1 has a measurement tube having a flow path through which a fluid flows, and is positioned on the upstream side and the downstream side of the flow path, and the shaft of the measurement tube An ultrasonic flowmeter that arranges at least one pair of ultrasonic sensors arranged on a line inclined with respect to each other and measures the flow rate of fluid by transmitting and receiving ultrasonic waves between the ultrasonic sensors,
The ultrasonic sensor is fixed in a sensor case,
The sensor case is fixed to the measurement tube from a direction orthogonal to the axial direction of the measurement tube.

According to a second aspect of the present invention, in the first aspect of the present invention, the measurement pipe is provided with a mounting portion having a mounting hole whose central axis is an axis orthogonal to the axial direction of the measurement pipe, and the sensor case Forming the tube,
The sensor case is fixed to the measurement tube from a direction orthogonal to the axial direction of the measurement tube by fitting the cylindrical portion of the sensor case into the attachment hole of the attachment portion of the measurement tube. Is.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a gap is provided between the ultrasonic sensor and the sensor case.

  According to a fourth aspect of the present invention, in the first, second, or third aspect of the present invention, an elastic material is disposed between the ultrasonic sensor and the sensor case.

  According to a fifth aspect of the present invention, in the first aspect of the present invention, a passage that communicates the inside of the sensor case and the inside of the measuring tube is provided.

  In the present invention, an ultrasonic sensor is fixed in advance in a sensor case, and this is unitized separately from the measurement tube. It can be a separate process, and the work efficiency of the main assembly process of the ultrasonic flowmeter can be increased.

  Further, the fine work of fixing the ultrasonic sensor in the sensor case can be performed in a small work space different from the main assembly place of the ultrasonic flowmeter.

  In addition, the unitized sensor case is fixed from the direction perpendicular to the axial direction of the measurement tube, so that the work can be performed from above obliquely with respect to the axis of the measurement tube like the conventional ultrasonic flowmeter. As compared with the conventional ultrasonic flowmeter, assembly work can be performed in a narrow work space.

The perspective view of the ultrasonic flowmeter in the example of the present invention. The front view of FIG. The side view of FIG. AA line sectional view of Drawing 3. The partial expanded sectional view cut | disconnected by the cross-sectional line which passes along the axial center of the terminal used for the Example of FIG. 1 parallel to the AA line of FIG. The perspective view of the measuring tube used for the Example of this invention. The top view of FIG. FIG. 6 is a cross-sectional view of a portion corresponding to FIG. 4 in FIG. 6. The perspective view of the state which attached the ultrasonic sensor to the sensor bracket used for the Example of this invention. The side view of FIG. The bottom view seen from the lower side of FIG. The front view seen from the right side of FIG. The rear view seen from the left side of FIG. BB sectional drawing of FIG. The perspective view of the sensor case used for the Example of this invention. FIG. 16 is a cross-sectional view of a portion corresponding to FIG. 4 in FIG. 15. The perspective view seen from the lower side of FIG. The schematic diagram for demonstrating the conventional ultrasonic flowmeter.

A mode for carrying out the present invention will be described based on the embodiment shown in FIGS.
An ultrasonic flowmeter 1 according to an embodiment of the present invention includes a measurement tube 2, a sensor case 3, a sensor bracket 4, an ultrasonic sensor 5, and a flow rate calculation display unit 6.

  The measuring tube 2 is formed of a metal such as stainless steel, and a flow path 9 is formed in the inside thereof, in which a fluid such as a gas circulates, both ends are open, and the openings are communicated with each other.

  As shown in FIG. 4, a pair of ultrasonic sensors 5, 5 is disposed on the upstream side and the downstream side of the flow path 9 with respect to the axial direction (XX) of the flow path 9. Are provided on an inclined straight line. That is, ultrasonic waves can be transmitted and received between the pair of ultrasonic sensors 5 and 5 in a direction obliquely crossing the axis XX of the flow path 2. And based on the propagation time of the ultrasonic wave between the ultrasonic sensors 5 and 5 from the upstream side to the downstream side and the propagation time of the ultrasonic wave between the ultrasonic sensors 5 and 5 from the downstream side to the upstream side, The flow rate of the fluid passing through the flow path 9 can be measured.

  The flow rate calculation display unit 6 is configured to calculate and display a flow rate based on a reception signal from the reception-side ultrasonic sensor 5.

  As shown in FIGS. 3 and 4, the flow channel 9 of the measurement tube 2 is formed in a cylindrical shape, and the inner diameter thereof is formed to be substantially the same over the entire length in the axial center XX direction. At both ends of the measurement tube 2, flanges 10, 10 projecting radially outward from the measurement tube 2 are provided.

  Each of the flanges 10 and 10 is formed with a plurality of through-holes 10a at appropriate intervals in the circumferential direction around the axis XX of the flow path 9. A feed pipe (not shown) for circulating a fluid is connected to the outside of each of the flanges 10 and 10 in the axial direction XX, and a bolt is connected to a through hole of the flange 10 and a through hole provided in the feed pipe. Is inserted, and the bolt and the nut are screwed together so that the measuring pipe 2 and the feeding pipe can be connected. With the feeding pipe to be connected, the axial direction XX of the flow path 9 can be arranged so as to be positioned in an arbitrary direction such as a vertical direction or a horizontal direction. Moreover, the mounting angle in the circumferential direction of the ultrasonic flowmeter 1 with respect to the feed pipe can be changed by changing the mutual connection position of the through hole of the flange 10 and the through hole of the feed pipe. ing.

  2-4, the axial direction XX of the flow path 9 is horizontal, and the axial direction of the display stand 6a of the flow rate calculation display unit 6 is vertical (the flow rate calculation display unit 6 is upward). When arranged so as to be positioned, in FIG. 3, the angle θ of the line connecting the axes of the ultrasonic sensors 5 and 5 with respect to the horizontal direction is 22.5 degrees.

  As shown in FIGS. 6 and 7, a mounting hole 11 for mounting the display stand 6 a of the flow rate calculation display unit 6 is formed in the peripheral wall of the measuring tube 2.

  As shown in FIGS. 6 to 8, attachment portions 12 and 12 for attaching the sensor case 3 having the ultrasonic sensor 5 are provided on the peripheral wall of the measurement tube 2 at the left and right portions in FIG. In the axial direction XX of the measuring tube 2, the upstream side and the downstream side of the measuring tube 2 are provided, one each, two in total, and 180 ° apart in the circumferential direction of the measuring tube 2. Yes. That is, when the ultrasonic sensors 5 are attached to the respective attachment portions 12, one ultrasonic sensor 5 is positioned on the upstream side of the flow path 9, and the other ultrasonic sensor 5 is on the downstream side of the flow path 9. The attachment portions 12 and 12 are provided so that the ultrasonic sensors 5 and 5 can be attached at positions where the ultrasonic sensors 5 and 5 can transmit and receive each other.

  As shown in FIGS. 6 to 8, the mounting portion 12 has a cylindrical mounting hole 12 a penetrating inside and outside of the measuring tube 2, and an axis ZZ of the mounting hole 12 a and XX of the measuring tube 2. That is, the channel 9 is formed so as to be orthogonal to the axis XX. The inner wall in the axial direction of the mounting hole 12a (the inner peripheral surface side of the measuring tube 2) and the inner wall in the axial direction XX of the measuring tube 2 are in the axial direction ZZ of the mounting hole 12a. It is formed on the inclined surface 12b whose diameter increases from the outside toward the inside. Further, the outer surface of the mounting portion 12 is orthogonal to the axis ZZ of the mounting hole 12a, that is, orthogonal to the axis ZZ orthogonal to the axis XX of the measuring tube 2 and circular. Is formed on the mounting surface 12c. As shown in FIGS. 6 and 7, four female screws 12 d are formed on the mounting surface 12 c at appropriate intervals in the circumferential direction around the axis of the mounting hole 12.

  Positioning means 13 having an outer peripheral surface in the shape of an arc centering on the axis ZZ of the mounting portion 12 and a flat inner surface on the central portion side in the axial direction XX of the measuring tube 2 on the mounting surface 12c. The projection surface 12c is provided so as to protrude outward in the radial direction of the measurement tube 2.

Next, the sensor case 3 will be described in detail.
The sensor case 3 is formed of a metal such as stainless steel, and as shown in FIGS. 15 to 17, the attachment portion 15, the cylinder portion 16, the connection portion 17, the storage portion 18, and the neck portion 19 are integrally formed. Has been.

  As shown in FIGS. 16 and 17, the cylindrical portion 16 is formed in a cylindrical shape having a circular outer cross section, and the outer diameter R1 thereof is the same as or slightly smaller than the inner diameter R2 of the mounting hole 12a of the mounting portion 12. Is set. A groove portion 16a for fitting the O-ring 55 is formed in the base portion of the cylindrical portion 16 over the entire circumferential direction, and a lower end surface (a surface on the axial center side of the measuring tube 2) in FIG. As shown in FIGS. 4 and 16, the measurement tube 2 is formed on an inclined surface 16 b that is inclined toward the axial center side of the measurement tube 2 from the inner side to the outer side in the axial direction XX. As shown in FIG. 17, two mounting holes 16c for attaching the sensor bracket 4 are provided in the peripheral portion of the inclined surface 16b, and a female screw is engraved in the mounting hole 16c. Yes.

  The base portion of the cylindrical portion 16 is integrally formed with a hook-shaped attachment portion 15 that is orthogonal to the axis C-C of the cylindrical portion 16 and protrudes outward from the cylindrical portion 16. As shown in FIG. 15, the mounting portion 15 is formed in a substantially circular flat plate shape, and the outer diameter of the mounting portion 15 and the outer diameter of the mounting surface 12 c of the mounting portion 12 are substantially the same. A set portion corresponding to the positioning means 13 of the mounting portion 12 is formed with a cutout portion 15a formed by cutting out the portion. Then, when attaching the sensor case 3 to the mounting portion 12, the mounting position of the sensor case 3 with respect to the mounting portion 12 can be positioned by bringing the notch portion 15 a into contact with the inner surface of the positioning means 13. It can be done. A flat mounting surface 15 c that is orthogonal to the axis CC of the cylindrical portion 16 is formed on the cylindrical portion 16 side of the mounting portion 15.

  Four through holes 15b are formed in the mounting portion 15 at positions corresponding to the female screws 12d of the mounting surface 12c.

  As shown in FIGS. 15 and 16, a neck portion 19 is provided on a radially outer portion (upper portion in FIG. 16) from the axial center of the measurement tube 2 in the attachment portion 15, and the axial center of the measurement tube 2 of the neck portion 19. A connecting portion 17 that protrudes in a direction parallel to the axis XX of the measuring tube 2 is provided on the outer side in the radial direction (upper part in FIG. 16). An opening 17a for inserting the joint 21 of the pipe 20 shown in FIG. 1 is formed in the connecting portion 17, and a space (passage) 22 communicating with the opening 17a is formed. On the inner wall of the space 22, a female screw 17b screwed with a male screw provided on the joint 21 is engraved with a predetermined length inward from the opening end of the opening 17a.

  A hole 17c for communicating the space 22 with the outside is formed in the upper part of the connecting portion 17 in FIG. 16, and an airtight terminal 35 to be described later is attached to the wall 22a facing the hole 17c inside the space 22. Two mounting holes 23 are formed. The space 22 communicates with the inside of the storage portion 18 through the mounting hole 23.

  A storage portion 18 that can store the sensor bracket 4 is formed inside the cylindrical portion 16, the attachment portion 15, and the neck portion 19, and the storage portion 18 has an opening 18 a on the inclined surface 16 b side of the cylindrical portion 16. And it is formed in the bottomed shape which has the said wall 22a in the back part on the opposite side to the inclined surface 16b. As shown in FIG. 16, the storage portion 18 has an axis FF inclined with respect to the axis CC of the cylindrical portion 16, and an opening 18 a of the storage portion 18 is formed in the axial direction of the measurement tube 2. It is formed so as to face inward.

  The storage portion 18 has a cylindrical large-diameter portion 18b positioned in the radially inner direction of the measuring tube 2 and an inner diameter smaller than the inner diameter of the large-diameter portion 18b, and is positioned in the radially outward direction of the measuring tube 2. A cylindrical small-diameter portion 18c.

  The peripheral wall of the cylindrical portion 16 is formed with a passage 26 that communicates the outside with the inside of the small diameter portion 18c, and an opening 26a on the outer side of the passage 26 is formed as shown in FIGS. When the sensor case 3 is attached to the measuring tube 2, the sensor case 3 is formed so as to open into the flow path 9. That is, the passage 26 communicates the inside of the housing portion 18 (sensor bracket 4) of the sensor case 3 with the inside of the flow path 9 of the measuring tube 2.

Next, the sensor bracket 4 and the ultrasonic sensor 5 will be described in detail with reference to FIGS.
The sensor bracket 4 is integrally formed of resin. The sensor bracket 4 has a pair of plate-like side walls 30, 30 formed by a part of the circumference centered on the axis EE, and there is no wall between both side walls 30, 30 in the circumferential direction. It has an opening 30a. A circular bottom plate 31 is fixed to one end of the side walls 30, 30 in the axial direction EE. On the inner side surface of the bottom plate 31, there are provided two projecting portions 31a, 31a projecting in the inner direction, and the axial center portion of each projecting portion 31a is formed with a hole 31b penetrating in the axial direction, The hole 31b opens to the outer side of the bottom plate 31. A large-diameter hole 31c having an inner diameter larger than the inner diameter of the hole provided in the protruding portion 31a is formed on the outer side of the hole 31b in the bottom plate 31.

  As shown in FIG. 14, two metal terminals 32, 32 are inserted into the respective holes 31b, 31c, and both end portions of the terminals 32 protrude inward and outward from the holes 31b, 31c. An insulating rubber 33 is fixed to the outer periphery of the terminal 32 protruding outward from the hole 31c. One end of the insulating rubber 33 is fitted into the large-diameter hole 31c, and is formed in a truncated cone shape whose diameter gradually decreases from the large-diameter hole 31c toward the outside. The terminal 32 protrudes outward from the insulating rubber 33. As shown in FIG. 13, an insulating rubber 34 is disposed on the peripheral edge of the terminals 32, 32 on the outer surface of the bottom plate 31. The terminal 32 and the insulating rubber 33 constitute an airtight terminal 35.

  An arc-shaped reinforcing member 36 centering on the axis of the sensor bracket is provided between the side walls 30 and 30 at the other end of the side walls 30 and 30. The reinforcing member 36 is provided only on one side in the circumferential direction of the both side walls 30, 30, and the side walls 30, 30 on the side facing the reinforcing member 36 are open.

  The side walls 30, 30 and the reinforcing member 36 have three arms 38, 38, 38 that protrude from the side wall 30 and the reinforcing member 36 in the direction opposite to the bottom plate 31 (ultrasonic sensor 5). However, the sensor bracket is fixedly provided with appropriate intervals (substantially equal intervals in the embodiment) in the circumferential direction around the axis EE of the sensor bracket. Accordingly, there is a gap between the arm portions 38 in the circumferential direction. A hook-shaped mounting portion 39 protrudes outward from the arm portion 38 (from the axis EE of the sensor bracket) at the tip portion of the arm portion 38, 38, 38 (the side portion opposite to the side wall 30). Is provided. A sensor housing portion 50 is formed by a hole 39 a at the center of the attachment portion 39 and a space inside the three arm portions 38.

  As shown in FIGS. 10, 11, and 14, the arm portion 38 has a base end that expands outward from the axis of the sensor bracket, and a diameter-expanding portion 38 a that extends from the axis of the sensor bracket to the attachment portion 39. On the other hand, it is composed of a support portion 38b formed substantially parallel to the axis EE of the sensor bracket. A groove 40 is formed inside the base end side of the support portion 38b.

  As shown in FIGS. 9 and 12, the mounting portion 39 is provided with two through holes 39b for mounting.

  The ultrasonic sensor 5 is fitted and disposed in the sensor storage portion 50 inside the three arm portions 38. As shown in FIG. 14, the ultrasonic sensor 5 has a transmission / reception surface 41 for transmitting and receiving ultrasonic waves at one end thereof, and the transmission / reception surface 41 is provided so as to be positioned in the hole 39 a of the attachment portion 39. Yes. Further, a gap 45 is formed between the outer peripheral surface of the wave transmitting / receiving surface 41 of the ultrasonic sensor 5 and the inner peripheral surface of the hole 39 a of the attachment portion 39. That is, a gap 45 is formed between the ultrasonic sensor 5 and the sensor case 3.

  In the ultrasonic sensor 5, an elastic material 42 such as a cylindrical rubber is disposed to be engaged with the ultrasonic sensor 5 over the entire side surface of the side peripheral portion. The elastic material 42 is formed in a cylindrical shape and is not provided on the wave transmitting / receiving surface 41 and the back surface 5a. In other words, the elastic material 42 is disposed between the outer peripheral surface of the ultrasonic sensor 5 and the arm portion 38, and the ultrasonic sensor 5 does not contact the sensor bracket 4 directly but contacts the elastic material 42. is doing.

  As shown in FIG. 14, a protrusion 42a protruding outward from the axis of the ultrasonic sensor 5 is integrally formed on the base of the elastic member 42 over the entire circumference. The arm portion 38 is engaged with the groove 40. By engaging the protrusion 42 a in the groove 40, the ultrasonic sensor 5 and the elastic material 42 can be locked and held on the arm 38.

  As shown in FIGS. 10 and 14, a lead wire 46 connected to the ultrasonic sensor 5 protrudes from the back surface 5 a of the ultrasonic sensor 5, and the tip of the lead wire 46 is connected to the terminal 32. As shown in FIG. 5, the terminal 32 and the flow rate calculation display unit 6 are connected by a connection line 47 disposed in the pipe 20. Joints 21 having male threads are fixed to both ends of the pipe 20.

Next, a method for assembling the ultrasonic flowmeter 1 will be described.
First, the elastic material 42 is fitted and attached to the side periphery of the ultrasonic sensor 5.

  Next, the ultrasonic sensor 5 is inserted into the sensor insertion portion 50 together with the elastic material 42 from the hole 39 a of the attachment portion 39 of the sensor bracket 4, and the protruding portion 42 a of the elastic material 42 is connected to the arm portion of the sensor bracket 4. As shown in FIG. 14, the ultrasonic sensor 5 is attached to the sensor bracket 4, and the ultrasonic sensor 5 is locked inside the three arm portions 38.

  Next, as shown in FIG. 14, the lead wire 46 of the ultrasonic sensor 5 is soldered to the terminal 32 and is electrically connected.

  Next, with respect to the sensor case 3 not attached to the measuring tube 2, the sensor bracket 4 is accommodated in the accommodating portion 18 from the terminal 32 side through the opening 18 a of the sensor case 3, and the airtight terminal 35. The insulating rubber 33 is fitted into the mounting hole 23 of the storage portion 18, and the terminal 32 is protruded from the mounting hole 23 in the direction opposite to the storage portion 18.

  Next, a bolt is inserted into the hole 39b of the mounting portion 39 of the sensor bracket 4 and the mounting hole 16c of the sensor case 3, and screwed into the female screw in the mounting hole 16c, so that the sensor bracket 4 is fixed to the sensor case 3. Set up. That is, the ultrasonic sensor 5 is fixed to the sensor case 3.

Next, the O-ring 55 is fitted into the groove 16a.
Next, from the outside of the measuring tube 2, the cylindrical portion 16 of the sensor case 3 is fitted into the mounting hole 12 a of the mounting portion 12 of the measuring tube 2 from the direction orthogonal to the axis XX of the measuring tube 2, The outer surface of the cutout portion 15 a of the attachment portion 15 of the sensor case 3 is brought into contact with the inner surface of the positioning means 13, and the attachment surface 15 c of the attachment portion 15 is brought into contact with the attachment surface 12 c of the attachment portion 12.

  Next, a bolt 51 is inserted into the through hole 15 b of the attachment portion 15 of the sensor case 3, and the bolt 51 is screwed into the female screw 12 d of the attachment surface 12 c of the measurement tube 2. A pair of sensor cases 3 and 3 are fixed in a direction perpendicular to the axial direction of the nine.

Next, the display stand 6 a of the flow rate calculation display unit 6 is attached to the attachment hole 11 of the measurement tube 2.
Next, the joint 21 of the pipe 20 is inserted from the opening 17a of the connecting portion 17, the screw of the joint 21 and the female screw 17b are screwed together to connect the pipe 20 to the connecting portion 17, and the hole 17c. Is used as a working hole, and one end of the connecting wire 47 is soldered to the terminal 32, and the lid 52 is fitted into the hole 17c. As shown in FIG. 1, the other end of the pipe 20 is connected to the flow rate calculation display unit 6, and the other end of the connection line 47 in the pipe 20 is also connected to the flow rate calculation display unit 6. Thereby, the ultrasonic sensor 5 and the flow rate calculation display unit 6 are electrically connected to form the ultrasonic flow meter 1.

  The ultrasonic flowmeter 1 according to the embodiment has the following operations and effects by having the above-described structure.

  Before attaching the sensor case 3 to the measuring tube 2, the ultrasonic sensor 5 is attached to the sensor bracket 4 in advance, and the sensor bracket 4 is attached to the sensor case 3, and these are separated from the measuring tube 2. In order to attach the unitized unit to the measuring tube 2, the unitizing step and the assembling step of attaching the unitized unit to the measuring tube 2 can be performed as separate steps. Thereby, the assembly work of the ultrasonic flowmeter 1 can improve work efficiency compared with the assembly work of the conventional ultrasonic flowmeter 101.

  In addition, since the unitized unit is fixed to the measurement tube 2 from a direction orthogonal to the axial direction XX of the measurement tube 2, the measurement tube can be configured like the conventional ultrasonic flowmeter 101. There is no need to work from an angle with respect to the shaft, and the assembly work can be performed in a narrow work space compared to the work space required for the assembly work of the conventional ultrasonic flowmeter 101.

  Further, the fine work of attaching the ultrasonic sensor 5 to the sensor bracket 4 and fixing the sensor bracket 4 in the sensor case 3 is different from the assembly process of attaching the unitized one to the measuring tube 2. The work space required for assembling the ultrasonic flowmeter 1 can be made narrower than the work space required for the assembly work of the conventional ultrasonic flowmeter 101.

  In the conventional ultrasonic flowmeter 101, the side surface of the ultrasonic sensor 104 is formed in a cylindrical shape, and is provided by directly fitting to the cylindrical socket portion 103. The side surface of the ultrasonic sensor 104 and the socket portion are provided. 103 is close. For this reason, the contact area between the ultrasonic sensor 104 and the socket 103 is large, and vibration generated from one ultrasonic sensor 104 propagates through the socket 103 and the measurement tube 102 to the other ultrasonic sensor 104. There is a problem that transmission noise may occur.

  In addition, there is a possibility that drains or oil contained in the gas flowing through the flow path 9 may collect around the ultrasonic sensor 104 in the socket portion 103, and vibrations generated from the ultrasonic sensor 104 may accumulate. There is a problem in that there is a possibility that noise may be transmitted to the other ultrasonic sensor 104 through the drain or oil.

  On the other hand, the ultrasonic flowmeter 1 of the present invention has a gap 45 or the like formed between the ultrasonic sensor 5 and the sensor bracket 4 or the sensor case 3, and the entire side surface of the ultrasonic sensor 5 and the sensor. An elastic material 42 is disposed between the bracket 4 and the elastic material 42 is held by three arm portions 38, 38, 38 that are spaced apart from each other, and the elastic material 42 around the ultrasonic sensor 5. By reducing the contact area of the sensor bracket 4 with respect to the noise, noise transmitted from one ultrasonic sensor 5 to the other ultrasonic sensor 5 can be reduced.

  In addition, by providing a gap 45 between the ultrasonic sensor 5 and the sensor bracket 4 or the sensor case 3, drain or oil does not stay around the ultrasonic sensor 5 and passes through the gap 45. While entering the storage portion 18 (sensor bracket 4) of the sensor case 3, a part of the drain, oil, or the like that has entered the storage portion 18 (sensor bracket 4) of the sensor case 3 passes through the passage 26, and the measurement tube. It is possible to escape (return) into the second flow path 9.

  This makes it difficult for drainage, oil, etc. to collect around the ultrasonic sensor 5, and vibrations, etc. generated from one ultrasonic sensor 5 are transmitted to the other ultrasonic sensor 5 through the accumulated drain, oil, etc. Noise can be reduced.

  Also, as shown in FIG. 4, when the axial direction XX of the flow path 9 is horizontal and the flow rate calculation display unit 6 is positioned above, as shown in FIG. Since the angle θ of the line connecting the axes of the ultrasonic sensors 5 and 5 with respect to the horizontal direction is 22.5 degrees, the ultrasonic sensor 5 is not positioned in the vertical lower part of the flow path 9 and It is possible to prevent a large amount of drain, oil or the like from adhering to the sonic sensor 5.

  Although a pair of ultrasonic sensors 5 and 5 are attached to the measurement tube 2, a plurality of pairs of ultrasonic sensors 5 and 5 such as two pairs and three pairs are attached to the measurement tube 2 and a plurality of measurement lines (super Ultrasonic waves may be transmitted and received through the propagation path of sound waves.

DESCRIPTION OF SYMBOLS 1 Ultrasonic flowmeter 2 Measuring tube 3 Sensor case 5 Ultrasonic sensor 9 Flow path 12 Mounting part 12a Mounting hole 16 Cylinder part 26 Passage 45 Gap 42 Elastic material

Claims (5)

At least one pair of ultrasonic sensors having a measurement tube having a flow path through which fluid flows, positioned on the upstream side and the downstream side of the flow path, and arranged on a line inclined with respect to the axis of the measurement tube An ultrasonic flowmeter that measures the flow rate of fluid by transmitting and receiving ultrasonic waves between the ultrasonic sensors,
The ultrasonic sensor is fixed in a sensor case,
An ultrasonic flowmeter, wherein the sensor case is fixed to the measurement tube from a direction orthogonal to the axial direction of the measurement tube. The measurement tube is provided with a mounting portion having a mounting hole whose central axis is an axis orthogonal to the axial direction of the measurement tube, and a cylindrical portion is formed in the sensor case,
The sensor case is fixed to the measurement tube from a direction orthogonal to the axial direction of the measurement tube by fitting the cylindrical portion of the sensor case into the attachment hole of the attachment portion of the measurement tube. The ultrasonic flowmeter according to claim 1.   The ultrasonic flowmeter according to claim 1, wherein a gap is provided between the ultrasonic sensor and the sensor case.   The ultrasonic flowmeter according to claim 1, wherein an elastic material is disposed between the ultrasonic sensor and the sensor case. The ultrasonic flowmeter according to any one of claims 1 to 4, further comprising a passage that communicates the inside of the sensor case and the inside of the measuring tube.

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