JP6097988B1 - Ultrasonic sensor unit, method for manufacturing the same, and ultrasonic measuring apparatus - Google Patents

Abstract

Provided is an ultrasonic sensor unit that can sufficiently ensure the adhesion of an elastic sheet to an ultrasonic radiation surface and can easily replace the elastic sheet. The ultrasonic sensor unit 2 includes a pair of ultrasonic sensors 11 and 12, sensor holders 42 and 43 having storage holes 35 and 59 in which the ultrasonic sensors 11 and 12 are arranged, and a rubber sheet 90 as an elastic sheet. . The ultrasonic sensors 11 and 12 have a convex-curved ultrasonic radiation surface 21 at the tip, and emit ultrasonic waves in a state where the tip is pressed against the measurement pipe 10. The rubber sheet 90 includes a first region 91 that covers the ultrasonic radiation surface 21 in a state of being stretched along the ultrasonic radiation surface 21, inner peripheral surfaces of the storage holes 35 and 59, and outer peripheral surfaces of the ultrasonic sensors 11 and 12. And a second region 92 that seals the gap. Selection diagram: Fig. 3

Description

  The present invention relates to an ultrasonic sensor unit including an ultrasonic sensor that propagates ultrasonic waves from an ultrasonic radiation surface, a manufacturing method thereof, and an ultrasonic measurement device that performs ultrasonic measurement using the ultrasonic sensor unit.

  Conventionally, ultrasonic measuring devices such as an ultrasonic flow meter that measures the flow rate of a liquid and a bubble detection device that detects bubbles contained in a liquid have been put to practical use as measuring devices using ultrasonic waves. These measuring devices are configured to propagate ultrasonic waves into the liquid in the pipe by pressing the ultrasonic radiation surface of the ultrasonic sensor against the pipe through which the liquid flows.

  When the pipe is formed of a hard resin material or the like, the adhesion between the ultrasonic radiation surface of the ultrasonic sensor and the pipe may be insufficient. For this reason, a rubber sheet (an elastic sheet functioning as an acoustic coupler) is provided between the ultrasonic radiation surface and the pipe so that the ultrasonic wave propagation efficiency is improved by improving the adhesion of the ultrasonic radiation surface to the pipe. (For example, refer to Patent Document 1). Moreover, as a rubber for dry coupling used for an ultrasonic sensor, a product of a rubber cap or a rubber sheet is provided (Non-patent Document 1). The rubber cap is a cap member that is attached to the front end side of the ultrasonic sensor so as to cover the ultrasonic radiation surface of the ultrasonic sensor, and is locked and held at the outer edge of the ultrasonic sensor.

Japanese translation of PCT publication No. 2002-520484 (see FIG. 2A etc.) IS L homepage, [Search May 23, 2016], Internet <URL: http: //www1.kcn.ne.jp/~isl/pdf/drycoupj.pdf>

  By the way, when a rubber cap is used as the coupling rubber, it is necessary to secure a holding force for the ultrasonic sensor, so that the thickness of the rubber is increased and the molding cost is increased. In particular, when the present invention is applied to an ultrasonic sensor having a small size of the ultrasonic radiation surface, it is necessary to make the rubber cap small, but it is difficult to mold the rubber cap and costs high. Furthermore, when the rubber cap is downsized, it becomes difficult to ensure a sufficient holding force for the ultrasonic sensor. In this case, since it is difficult to attach the rubber cap to the ultrasonic sensor, if a gap is generated between the ultrasonic radiation surface and the rubber cap due to misalignment or the like, accurate ultrasonic measurement cannot be performed.

  When a rubber sheet is used as the coupling rubber, it is necessary to manually hold the rubber sheet to the measurement site each time, and the workability is poor. For this reason, usually, a rubber sheet is bonded and fixed to the ultrasonic radiation surface using an adhesive or a double-sided tape. However, when the rubber sheet is bonded, a failure mode such as adhesion peeling may occur due to long-term use. Furthermore, if the rubber wears due to long-term use, the propagation efficiency of the ultrasonic wave is lowered, so that the rubber sheet needs to be replaced. In this case, it is difficult to cleanly remove the rubber sheet fixed with the adhesive from the ultrasonic radiation surface, and the replacement work of the rubber sheet takes time and cost.

  The present invention has been made in view of the above-described problems, and the object thereof is to ensure sufficient adhesion of the elastic sheet to the ultrasonic radiation surface and to easily replace the elastic sheet. An ultrasonic sensor unit that can be used is provided. Another object is to provide an ultrasonic measurement apparatus capable of performing ultrasonic measurement more reliably using the ultrasonic sensor unit. Furthermore, another object is to provide a manufacturing method suitable for manufacturing the ultrasonic sensor unit.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that an ultrasonic sensor having a convex-curved ultrasonic radiation surface at the front end portion, the front end surface and the rear end surface communicate with each other and the ultrasonic sensor is disposed. A sensor housing member formed with a housing hole, and the ultrasonic sensor in the housing hole is suppressed from the base end side, and the distal end portion of the ultrasonic sensor protrudes from the front end surface. An ultrasonic sensor unit that emits ultrasonic waves from the ultrasonic radiation surface in a state where the tip of the ultrasonic sensor is pressed against an object. A first region that covers the ultrasonic radiation surface in a state of being stretched along the sound wave radiation surface; an outer peripheral surface of the accommodation hole; an outer peripheral surface of the ultrasonic sensor; Between the gaps The ultrasonic sensor unit, characterized in that it comprises an elastic sheet and a second region for sealing the gap in Rukoto its gist.

  Therefore, according to the first aspect of the present invention, the elastic sheet has the first region and the second region located on the outer peripheral side, and the first region on the central side of the elastic sheet is an ultrasonic wave. It is provided so as to cover the radiation surface while being stretched along the radiation surface. By providing the elastic sheet in this manner, the ultrasonic radiation surface can be reliably adhered to the surface of the object. In particular, in the present invention, since the ultrasonic radiation surface is formed in a convex curved shape, the first region of the elastic sheet can be uniformly stretched, and the adhesion state of the elastic sheet to the ultrasonic radiation surface is excellent. Can be maintained. As a result, it is possible to prevent problems such as the elastic sheet being torn or air entering between the elastic sheet and the radiation surface, and the ultrasonic wave can be efficiently propagated to the object. Furthermore, since the gap between the inner peripheral surface of the storage hole and the outer peripheral surface of the ultrasonic sensor is sealed by the second region on the outer peripheral side of the elastic sheet, the airtightness in the sensor holder in which the ultrasonic sensor is stored is sealed. Sex is secured. As a result, it is possible to avoid problems such as corrosion or short-circuiting of the electrical terminals and connection wiring of the ultrasonic sensor in the sensor holder.

  The gist of the invention described in claim 2 is that, in claim 1, the elastic sheet is provided in an unbonded state and replaceable with respect to the ultrasonic radiation surface.

  Therefore, according to the invention described in claim 2, when the elastic sheet is worn by repeatedly using the ultrasonic sensor unit, the sensor holder is disassembled into the sensor housing member and the sensor holding member, and the ultrasonic sensor is replaced with the sensor holder. The elastic sheet can be easily replaced as a consumable part.

  According to a third aspect of the present invention, in the first or second aspect, the elastic sheet is a rubber sheet, and in the rubber sheet, the second region is compressed in the thickness direction of the rubber sheet, The gist of the present invention is that the first region is elongated in the surface direction of the rubber sheet and is thinner than the second region.

  Therefore, according to the invention described in claim 3, since the elastic sheet is a relatively inexpensive rubber sheet, the cost of components can be suppressed. Further, the rubber sheet has sufficient elasticity, and the second region is sandwiched between the storage hole and the ultrasonic sensor and compressed, so that the gap can be reliably sealed. Moreover, since the 1st area | region which covers an ultrasonic radiation surface in a rubber sheet expand | extends and becomes thin, the propagation efficiency of an ultrasonic wave can be improved more.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the elastic sheet is a self-bonding type in which an adhesive layer is laminated on a rubber base material and is in close contact with its own expansion and contraction. The gist is that it is a rubber sheet.

  Therefore, according to the invention described in claim 4, since the elastic sheet is a self-bonding rubber sheet, the second region on the outer peripheral side of the rubber sheet is compressed, so that the adhesion is increased, and the storage hole The gap between the inner peripheral surface of the ultrasonic sensor and the outer peripheral surface of the ultrasonic sensor can be reliably sealed. In addition, since the first region on the center side of the rubber sheet is expanded, the rubber sheet can be securely adhered along the ultrasonic radiation surface.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, a flange portion is formed on a proximal end side of the ultrasonic sensor, and the storage hole is smaller than the small diameter portion and the small diameter portion. And a stepped surface on which the flange portion can be locked from the rear end surface side of the sensor housing member at a connecting portion between the small diameter portion and the large diameter portion. The gist is that it is formed.

  Therefore, according to the fifth aspect of the present invention, in the storage member, the flange portion comes into contact with the stepped surface formed at the connection portion between the small diameter portion and the large diameter portion of the storage hole from the rear end surface side and is locked. Thus, the movement of the ultrasonic sensor in the axial direction in the storage hole can be restricted. With this configuration, the tip of the ultrasonic sensor can be reliably projected by a predetermined amount from the front end surface of the sensor housing member.

  The invention according to claim 6 is the invention according to claim 5, wherein the elastic sheet is a circular sheet, and the diameter thereof is larger than the inner diameter of the small diameter portion in the storage hole and larger than the inner diameter of the large diameter portion. The gist is that it is small.

  Therefore, according to the invention described in claim 6, since the diameter of the circular elastic body sheet is larger than the inner diameter of the small-diameter portion and smaller than the inner diameter of the large-diameter portion in the housing hole, it is elastic to the step surface of the housing hole. A body sheet can be arranged reliably. In this case, since the circular elastic sheet can be accurately positioned with respect to the storage hole, the assembly accuracy of the elastic sheet can be increased. As a result, alignment between the center of the ultrasonic radiation surface and the center of the elastic sheet can be accurately performed, and the elastic sheet can be easily formed in a state where the first region extends uniformly along the ultrasonic radiation surface. Can be installed.

  A seventh aspect of the present invention is the method according to any one of the first to sixth aspects, wherein the object is a measurement pipe for flowing a liquid, and a pair of the ultrasonic sensors are arranged to face each other with the measurement pipe interposed therebetween. And a biasing force is applied to the sensor holder to press the ultrasonic radiation surface of at least one of the pair of ultrasonic sensors against the measurement pipe and clamp the measurement pipe. The gist of the present invention is to further include a biasing member.

  Therefore, according to the seventh aspect of the present invention, the pair of ultrasonic sensors are arranged so as to face each other with the measurement pipe interposed therebetween, and the sensor holder holding at least one ultrasonic sensor is biased by the biasing member. Is done. As a result, the ultrasonic radiation surface of the ultrasonic sensor is pressed against the measurement pipe, and the measurement pipe is clamped by the pair of ultrasonic sensors. In this case, the ultrasonic wave can be efficiently propagated from the ultrasonic radiation surface of the ultrasonic sensor into the liquid in the measurement pipe, and ultrasonic measurement such as liquid flow measurement and detection of bubbles contained in the liquid is ensured. Can be done.

  The gist of the invention according to claim 8 is that, in claim 7, the measurement pipe is provided in the middle of an infusion tube through which the infusion as the liquid flows.

  Therefore, according to the eighth aspect of the invention, since the measurement pipe is provided in the middle of the infusion tube through which the infusion solution flows, ultrasonic waves are introduced into the infusion solution from the ultrasonic radiation surface of the ultrasonic sensor via the measurement pipe. Can be propagated efficiently, and ultrasonic measurement such as measurement of the flow rate of the infusion and detection of bubbles contained in the infusion can be reliably performed. Moreover, since the infusion tube is thin, the measurement piping connected to it can be formed thin. In this case, for example, a small sensor having a diameter of 15 mm or less can be used as the ultrasonic sensor, and the ultrasonic sensor unit can be formed compactly.

  According to a ninth aspect of the present invention, the ultrasonic sensor unit according to any one of the first to eighth aspects of the present invention is electrically connected to the ultrasonic sensor, and the supersonic wave is detected based on a detection signal of the ultrasonic sensor. The gist of the present invention is an ultrasonic measurement apparatus comprising a calculation means for performing calculation processing for sound wave measurement.

  Therefore, according to the ninth aspect of the invention, the detection signal of the ultrasonic sensor in the ultrasonic sensor unit is taken into the calculation means, and calculation processing for ultrasonic measurement is performed based on the detection signal. In this way, by configuring the ultrasonic measurement device using the ultrasonic sensor unit, the adhesion on the ultrasonic radiation surface of the ultrasonic sensor is ensured, so that the propagation efficiency of ultrasonic waves can be increased, Sound wave measurement can be performed more reliably. In addition, since the airtightness in the sensor holder is ensured, problems such as corrosion or short-circuiting of the electrical terminals and connection wiring of the ultrasonic sensor can be avoided.

  A tenth aspect of the present invention is a method of manufacturing the ultrasonic sensor unit according to the sixth aspect of the present invention, wherein in the sensor housing member, the elastic sheet is positioned while being positioned on the step surface of the housing hole. Sheet placement step, and inserting the ultrasonic sensor into the storage hole from the rear end surface side of the sensor storage member, and pressing the rear end surface using the sensor pressing member, The ultrasonic sensor is pushed into the small-diameter portion through the elastic sheet, and the ultrasonic radiation surface covered with the first region of the elastic sheet is projected from the front end surface of the sensor housing member, and A sensor pressing step for sealing a gap between the inner peripheral surface of the storage hole and the outer peripheral surface of the ultrasonic sensor in the second region; and the flange portion abuts on the stepped surface In a state in which, by fixing the sensor pressing member to the sensor housing member, a method of manufacturing the ultrasonic sensor unit, characterized in that it comprises a holder forming step of forming the sensor holder and the gist thereof.

  Therefore, according to the invention described in claim 10, in the sheet installation step, the elastic sheet is positioned and arranged on the step surface in the storage hole. Specifically, a circular elastic sheet is disposed on the step surface in a state of being aligned with the center of the storage hole. In the sensor pushing process, the ultrasonic sensor is inserted into the storage hole from the rear end surface side of the sensor storage member, and the rear end surface is suppressed using the sensor pressing member. Accordingly, the ultrasonic sensor is pushed into the small diameter portion of the storage hole via the elastic sheet. At this time, the second region on the outer peripheral side of the elastic sheet is fixed while being sandwiched between the inner peripheral surface of the storage hole and the outer peripheral surface of the ultrasonic sensor. Further, the first region on the center side of the elastic sheet is pulled by the movement of the ultrasonic radiation surface when the ultrasonic sensor is pushed into the storage hole, and extends uniformly along the radiation surface. Further, in the elastic sheet, the first region extends, whereas the excess sheet is gathered on the outer peripheral side. As a result, the second region of the elastic sheet is in close contact with the gap between the inner peripheral surface of the storage hole and the outer peripheral surface of the ultrasonic sensor. Thus, the ultrasonic radiation surface covered by the first region of the elastic sheet protrudes from the front end surface of the sensor housing member, and the inner surface of the housing hole and the outer circumferential surface of the ultrasonic sensor by the second region. And the gap is sealed. Thereafter, in the holder forming step, the sensor holder is formed by fixing the sensor holding member to the sensor housing member with the flange portion in contact with the stepped surface. When the ultrasonic sensor unit is manufactured through these steps, the first region of the elastic sheet secures the adhesion on the ultrasonic radiation surface of the ultrasonic sensor, so that the ultrasonic wave propagation efficiency can be increased. Sound wave measurement can be performed more reliably. Moreover, since the airtightness in the sensor holder is ensured by the second region of the elastic sheet, it is possible to avoid problems such as corrosion or short-circuiting of the electrical terminals and connection wirings of the ultrasonic sensor.

  As described above in detail, according to the inventions described in claims 1 to 8, the adhesiveness of the elastic sheet to the ultrasonic radiation surface can be sufficiently secured and the elastic sheet can be easily replaced. An ultrasonic sensor unit that can be provided can be provided. According to the ninth aspect of the present invention, it is possible to provide an ultrasonic measurement apparatus capable of performing ultrasonic measurement more reliably using the ultrasonic sensor unit. Furthermore, according to the invention described in claim 10, it is possible to provide a manufacturing method suitable for manufacturing the ultrasonic sensor unit.

The perspective view which shows schematic structure of the ultrasonic flowmeter of 1st Embodiment. The disassembled perspective view which shows the ultrasonic sensor unit of 1st Embodiment. Sectional drawing which shows the ultrasonic sensor unit of 1st Embodiment. The block diagram which shows the electrical constitution of an ultrasonic flowmeter. Explanatory drawing which shows the manufacturing method of an ultrasonic sensor unit. Explanatory drawing which shows the manufacturing method of an ultrasonic sensor unit. Explanatory drawing which shows the manufacturing method of an ultrasonic sensor unit. Explanatory drawing which shows the ultrasonic sensor unit for experiment. The graph which shows the transmission / reception sensitivity of the ultrasonic wave according to the presence or absence of a rubber sheet. The perspective view which shows the ultrasonic sensor unit of 2nd Embodiment.

[First Embodiment]
Hereinafter, a first embodiment in which the present invention is embodied in an ultrasonic flowmeter as an ultrasonic measuring device will be described in detail with reference to the drawings.

  As shown in FIG. 1, the ultrasonic flow meter 1 includes an ultrasonic sensor unit 2 and a measurement control device 3 as a calculation unit. The ultrasonic flowmeter 1 measures the flow rate of an infusion solution W1 (liquid such as a drug solution) flowing through the infusion tube 4 in an ultrasonic propagation time difference method at a medical site, for example.

  As shown in FIG. 1 to FIG. 3, the ultrasonic sensor unit 2 includes a pair of ultrasonic waves 10 and a measurement pipe 10 (target object) connected to the infusion tube 4 and the measurement pipe 10. Sensors 11, 12, a base 14 on which the ultrasonic sensors 11, 12 and the measurement pipe 10 are installed, and a spring unit 15 (biasing means) that urges the ultrasonic sensor 12 toward the measurement pipe 10. .

  The measurement pipe 10 has a straight pipe portion 17 and an inlet 18 and an outlet 19 connected to the straight pipe portion 17, and the infusion tube 4 is connected to the inlet 18 and the outlet 19, respectively. That is, the measurement pipe 10 is provided in the middle of the infusion tube 4, and the infusion solution W <b> 1 flows through the straight pipe portion 17 from the inlet 18 toward the outlet 19. The measurement pipe 10 is formed using a resin material such as a volatilate carbonate, for example.

  As shown in FIG. 3, the pair of ultrasonic sensors 11 and 12 are both sensors having the same structure. Each ultrasonic sensor 11, 12 is a small sensor having a diameter of 10 mm, and has a convex curved ultrasonic radiation surface 21 at the tip. More specifically, the ultrasonic sensors 11 and 12 have a cylindrical sensor case whose outer edge portion on the distal end side is chamfered in the shape of an R surface, a cap-shaped sensor case 26 having a flange portion 25 on the proximal end side, and a sensor case 26. And an ultrasonic transducer 27 capable of transmitting and receiving ultrasonic waves. The ultrasonic transducer 27 is a piezoelectric element formed in a disk shape using piezoelectric ceramics such as PZT.

  In the cap-shaped sensor case 26, the vibration surface of the ultrasonic transducer 27 is bonded and fixed to the inner surface side of the top portion serving as the tip portion, and the outer surface of the tip portion is the ultrasonic radiation surface 21. The ultrasonic sensors 11 and 12 emit ultrasonic waves from the ultrasonic radiation surface 21 in a state in which the ultrasonic radiation surface 21 at the tip is pressed against the measurement pipe 10. A wiring 28 connected to the ultrasonic transducer 27 is drawn to the outside in the sensor case 26, and a gap in the case 26 is filled with a resin filler 29 in a state where the ultrasonic transducer 27 is stored. The ultrasonic sensors 11 and 12 are formed by sealing the inside of the sensor case 26 with the resin filler 29. In the ultrasonic sensors 11 and 12, the wiring 28 is drawn out from the center of the end surface (base end surface) on the base end portion side where the flange portion 25 is formed.

  As shown in FIGS. 1 to 3, the base 14 is formed in a substantially square plate shape using a resin material such as ABS resin, and a fixed wall portion 31 serving as a sensor housing member projects from one end of the base 14. Has been. A storage hole 35 that communicates the front end surface 33 and the rear end surface 34 is formed in the fixed wall portion 31, and the ultrasonic sensor 11 is disposed in the storage hole 35. The storage hole 35 includes a small diameter portion 37 and a large diameter portion 38 positioned on the rear end face 34 side of the small diameter portion 37, and a flange of the ultrasonic sensor 11 is connected to a connection portion between the small diameter portion 37 and the large diameter portion 38. A step surface 39 (see FIG. 3) is formed on which the portion 25 can be locked from the rear end surface 34 side. A sensor holding plate 41 (sensor holding member) is screwed to the rear end surface 34 of the fixed wall portion 31. The sensor restraining plate 41 restrains the ultrasonic sensor 11 disposed in the storage hole 35 from the base end side, and the distal end portion (ultrasonic radiation surface 21) of the ultrasonic sensor 11 is fixed to the fixed wall portion 31. Fix in a state of protruding from the front end face 33. The sensor holding plate 41 is also made of a resin material such as ABS resin.

  In the present embodiment, the sensor holder 42 is configured by the fixed wall portion 31 of the base 14 and the sensor holding plate 41. The sensor holder 42 is a fixed sensor holder that is provided so as not to move with respect to the base 14. On the other hand, a movable sensor holder 43 is disposed on the other end side of the base 14 facing the fixed wall portion 31 so as to be movable in the longitudinal direction of the base 14. Specifically, a holder housing groove 45 (see FIG. 2) is formed on the other end side of the base 14 so as to be cut out in the longitudinal direction of the base 14. A pair of guide protrusions 46 functioning as guides for moving the sensor holder 43 are provided along the longitudinal direction of the base 14 at the upper side portions of the holder housing groove 45 facing each other.

  The movable sensor holder 43 includes a holder main body 50 (sensor storage member) including a substantially cylindrical storage portion 48 that stores the ultrasonic sensor 12 and a pedestal portion 49 provided below the storage portion 48. A sensor restraining lid 51 (sensor restraining member) that restrains the ultrasonic sensor 12 housed in the housing portion 48 from the base end side thereof is provided. The holder main body 50 and the sensor holding lid 51 of the sensor holder 43 are also made of a resin material such as ABS resin.

  In the sensor holder 43, a pair of guide portions 54 each having a guide groove 53 formed so as to extend along the axial direction is provided on the outer peripheral surface of the storage portion 48 of the holder main body 50. In the guide portion 54, the guide groove 53 is formed between the two ridge portions 55. The sensor holder 43 can be slid in the axial direction by fitting the pedestal portion 49 into the holder housing groove 45 in a state where the guide groove 53 of the guide portion 54 in the holder main body 50 is fitted to the guide protrusion 46 on the base 14 side. Is provided.

  A storage hole 59 that connects the front end surface 57 and the rear end surface 58 is formed in the storage portion 48 of the holder body 50, and the ultrasonic sensor 12 is disposed in the storage hole 59. The storage hole 59 includes a small diameter portion 61 and a large diameter portion 62 positioned on the rear end face 58 side of the small diameter portion 61, and a flange of the ultrasonic sensor 12 is provided at a connection portion between the small diameter portion 61 and the large diameter portion 62. A step surface 63 (see FIG. 3) is formed on which the portion 25 can be locked from the rear end surface 58 side. The sensor holding lid 51 holds the ultrasonic sensor 12 disposed in the storage hole 59 from the base end side, and the front end portion 21 of the ultrasonic sensor 12 protrudes from the front end surface 57 of the holder body 50. Fix in the state where Here, in the storage portion 48, a through hole 65 communicating with the storage hole 59 is formed at a position closer to the center than the guide portion 54, and a spring pin 66 is inserted into the through hole 65. When the spring pin 66 contacts the sensor holding lid 51 in the storage hole 59, the sensor holding lid 51 is fixed to the storage portion 48.

  The spring unit 15 includes a coiled compression spring 70 and a side plate 71 screwed to the end surface of the base 14, and the ultrasonic radiation surface 21 of the ultrasonic sensor 12 is pressed against the measurement pipe 10 for measurement. An urging force for clamping the pipe 10 is applied to the sensor holder 43. Specifically, a hollow cylindrical spring accommodating portion 73 for accommodating and fixing the proximal end side of the compression spring 70 is formed on the side plate 71 of the spring unit 15. The distal end side of the compression spring 70 fixed to the spring unit 15 abuts on the sensor holding lid 51, and the urging force of the compression spring 70 acts on the sensor holder 43 via the sensor holding lid 51.

  At the rear end side of the holder main body 50, a connection portion between the storage portion 48 and the pedestal portion 49 is formed with a notch 75 for fixing the tip end portion of the pulling rod 74, and on the side surface of the pedestal portion 49. A through hole 77 for inserting the spring pin 66 is formed. The base end side of the pulling rod 74 has a round bar shape, and the leading end of the pulling rod 74 is formed in a thin plate shape so as to be inserted into the notch 75. A through hole 78 for inserting the spring pin 66 is formed in the proximal end portion and the distal end portion of the pulling rod 74. The pull rod 74 is inserted into the cutout portion 75 of the holder body 50 and the spring pin 66 is inserted into the through hole 78 at the tip portion of the pull rod 74 through the through hole 77 of the holder body 50. 74 is fixed to the holder body 50. Further, the side plate 71 of the spring unit 15 is formed with a through hole 79 through which the base end portion of the pull bar 74 is inserted and protrudes outside the unit, and the base end portion of the pull bar 74 protruding from the through hole 79 is formed. The grip 81 is fixed by using a spring pin 66. By pulling the grip 81, the sensor holder 43 is pulled back against the biasing force of the compression spring 70 via the pulling rod 74. As a result, the clamp of the measurement pipe 10 by the pair of ultrasonic sensors 11 and 12 is released, and the measurement pipe 10 installed on the base 14 can be detached and the measurement pipe 10 can be reset.

  In the base 14, a thick portion 83 formed to be slightly thick at a position between the fixed sensor holder 42 and the movable sensor holder 43 (between the pair of ultrasonic sensors 11 and 12). A pipe arrangement groove 84 formed in a concave shape is formed in the central portion of the thick wall portion 83. A straight pipe portion 17 of the measurement pipe 10 is arranged along the pipe arrangement groove 84. In this state, the pair of ultrasonic sensors 11 and 12 held by the sensor holders 42 and 43 are arranged to face each other with the straight pipe portion 17 interposed therebetween.

  In the present embodiment, in the fixed sensor holder 42 and the movable sensor holder 43, the rubber sheet 90 (elastic body sheet) can be exchanged in an unbonded state with respect to the ultrasonic radiation surface 21 of the ultrasonic sensors 11 and 12. ) Is provided. The rubber sheet 90 is positioned on the outer peripheral side of the first region 91 and the first region 91 covering the ultrasonic radiation surface 21 in a state of being stretched along the ultrasonic radiation surface 21, and the inner periphery of the storage holes 35 and 59. And a second region 92 that seals the gap by being sandwiched in the gap between the surface and the outer peripheral surfaces of the ultrasonic sensors 11 and 12. The rubber sheet 90 is a self-fusing type rubber sheet that is formed by laminating an adhesive layer on a silicon rubber base material, and is in close contact with its own expansion and contraction. As shown in FIG. 7, in the rubber sheet 90, the second region 92 is compressed in the thickness direction of the rubber sheet 90, while the first region 91 is expanded in the surface direction of the rubber sheet 90. The thickness t1 of the region 91 is smaller than the thickness t2 of the second region 92 (t1 <t2). In the present embodiment, a circular sheet is used as the rubber sheet 90. The rubber sheet 90 has a diameter in an unmounted state (see FIG. 2) before being mounted on the sensor holders 42 and 43, for example, about 14 mm, and the inner diameters of the small diameter portions 37 and 61 in the storage holes 35 and 59 (for example, 11 mm) and smaller than the inner diameter (for example, 15 mm) of the large diameter portions 38 and 62. Further, the thickness of the rubber sheet 90 in the unmounted state is about 0.5 mm.

  In the fixed sensor holder 42, the wiring 28 extending from the base end portion of the ultrasonic sensor 11 is drawn out of the ultrasonic sensor unit 2 through the through hole 95 of the sensor holding plate 41 and connected to the measurement control device 3. Yes. In the movable sensor holder 43, the wiring 28 extending from the base end of the ultrasonic sensor 12 passes through the center hole 96 of the sensor holding lid 51, the inside of the compression spring 70, and the through hole 97 of the side plate 71. It is pulled out of the unit 2 and connected to the measurement control device 3. That is, each ultrasonic sensor 11, 12 of the ultrasonic sensor unit 2 is electrically connected to the measurement control device 3 via the wiring 28.

  The measurement control device 3 obtains the flow rate of the infusion solution W1 according to the propagation time difference between the ultrasonic waves transmitted and received by the ultrasonic sensors 11 and 12 by calculation. Hereinafter, the configuration of the measurement control device 3 will be described in detail with reference to FIG.

  As illustrated in FIG. 4, the measurement control device 3 includes a signal processing unit 100, an arithmetic processing unit 101, an input device 102, a display device 103, and the like. The signal processing unit 100 includes a circuit that outputs a drive signal for driving the ultrasonic sensors 11 and 12, a circuit that detects a propagation time of the ultrasonic wave, and the like. The arithmetic processing unit 101 is a processing circuit configured to include a conventionally known CPU 105, memory 106, and the like. In the arithmetic processing unit 101, a control program and data are stored in the memory 106, and the CPU 105 performs a flow rate arithmetic process and a display process according to the control program in the memory 106.

  More specifically, the signal processing unit 100 drives the ultrasonic sensors 11 and 12 to transmit / receive ultrasonic waves to / from each other. At this time, in the pair of ultrasonic sensors 11 and 12, the signal processing unit 100 transmits the ultrasonic wave transmitted from the upstream ultrasonic sensor 11 and received by the downstream ultrasonic sensor 12 in the positive direction (infusion W1). The propagation time of the ultrasonic wave propagating in the positive direction with respect to the current flow) is detected. Further, the signal processing unit 100 propagates in the reverse direction of the ultrasonic wave transmitted from the downstream ultrasonic sensor 12 and received by the upstream ultrasonic sensor 11 (reverse to the flow of the infusion W1). Ultrasonic propagation time) is detected. Then, the signal processing unit 100 outputs the forward propagation time and the reverse propagation time to the arithmetic processing unit 101. The arithmetic processing unit 101 takes in the forward direction propagation time and the reverse direction propagation time output from the signal processing unit 100, and obtains the flow rate of the infusion W1 according to the propagation time by calculation.

  The input device 102 includes various operation buttons and performs measurement start / end, display mode setting, and the like. The display device 103 is a liquid crystal display, for example, and displays the flow rate obtained by the arithmetic processing unit 101.

  Next, a method for manufacturing the ultrasonic sensor unit 2 by assembling each member will be described.

  First, as shown in FIG. 5, in the base 14, the rubber sheet 90 is positioned while being positioned on the step surface 39 in the storage hole 35 of the fixed wall portion 31 (sheet placement step). Here, a circular rubber sheet 90 is disposed on the stepped surface 39 in a state of being aligned with the center of the storage hole 35. Thereafter, as shown in FIG. 6, the ultrasonic sensor 11 is inserted into the accommodation hole 35 from the rear end surface 34 side of the fixed wall portion 31, and the rear end surface 34 of the fixed wall portion 31 is moved using the sensor holding plate 41. Hold down. Thereby, as shown in FIG. 7, the ultrasonic sensor 11 is pushed into the small diameter portion 37 of the storage hole 35 via the rubber sheet 90 (sensor pushing step).

  At this time, the second region 92 on the outer peripheral side of the rubber sheet 90 is fixed in a state of being sandwiched between the inner peripheral surface of the storage hole 35 and the outer peripheral surface of the ultrasonic sensor 11. Further, the first region 91 on the center side of the rubber sheet 90 is pulled in the direction of the arrow A1 by the movement of the ultrasonic radiation surface 21 when the ultrasonic sensor 11 is pushed into the storage hole 35, and the radiation surface 21 thereof. (See arrow A1 in FIG. 7). Further, in the rubber sheet 90, the first region 91 extends, but the sheet surplus is gathered on the outer peripheral side. As a result, the second region 92 of the rubber sheet 90 is brought into close contact with the gap between the inner peripheral surface of the storage hole 35 and the outer peripheral surface of the ultrasonic sensor 11 in a compressed state from the direction of the arrow A2 (FIG. 7). Arrow A2). In this way, the ultrasonic radiation surface 21 covered with the first region 91 of the rubber sheet 90 protrudes from the front end surface 33 of the fixed wall portion 31, and the second region 92 and the inner peripheral surface of the storage hole 35. A gap with the outer peripheral surface of the ultrasonic sensor 11 is sealed. Further, in this state, the outer end of the second region 92 of the rubber sheet 90 is located near the central portion in the penetration direction of the storage hole 35. That is, the width of the second region 92 is about half of the length of the through hole 35 in the penetrating direction (axial direction). Note that the width of the second region 92 may be appropriately changed as long as the sealability can be ensured.

  Then, the sensor holder plate 42 is screwed and fixed to the rear end surface 34 of the fixed wall portion 31 in a state where the flange portion 25 of the ultrasonic sensor 11 is in contact with the stepped surface 93 of the storage hole 35, whereby the sensor holder 42. Is formed (holder forming step).

  Next, the movable sensor holder 43 is attached to the base 14. Specifically, the rubber sheet 90 is positioned and positioned on the step surface 63 in the storage hole 59 of the storage portion 48 of the holder body 50 (sheet placement step). Thereafter, the ultrasonic sensor 12 is inserted into the storage hole 59 from the rear end face 58 side of the storage portion 48, and the ultrasonic sensor 12 is pressed down using the sensor holding cover 51. Accordingly, the ultrasonic sensor 12 is pushed into the small diameter portion 61 of the storage hole 59 via the rubber sheet 90, and the ultrasonic radiation surface 21 covered with the first region 91 of the rubber sheet 90 is moved to the front end surface 57 of the storage portion 48. In addition, the gap between the inner peripheral surface of the storage hole 59 and the outer peripheral surface of the ultrasonic sensor 12 is sealed in the second region 92 (sensor pressing step). The sensor holder 43 is formed by fixing the sensor holding lid 51 to the storage portion 48 with the spring pin 66 in a state where the flange portion 25 of the ultrasonic sensor 12 is in contact with the stepped surface 63 of the storage hole 59. (Holder forming process). Further, after the leading end portion of the pulling rod 74 is inserted into the cutout portion 75 of the holder main body 50, the leading end portion is fixed by the spring pin 66. Thereafter, the guide groove 53 formed in the storage portion 48 of the holder main body 50 is fitted into the guide protrusion 46 in the holder storage groove 45 of the base 14, and the sensor holder 43 is slid along the guide protrusion 46 to enter the storage groove 45. Arrange.

  Next, the spring unit 15 is assembled to the end of the base 14. Specifically, the proximal end side of the compression spring 70 is accommodated in the spring accommodating portion 73 of the side plate 71, and the distal end side of the compression spring 70 is brought into contact with the sensor holding lid 51 in the accommodation hole 59. Further, the side plate 71 is screwed and fixed to the end portion of the base 14 with the base end portion of the pulling rod 74 inserted into the through hole 79 of the side plate 71. Then, the sensor holder 43 is slightly pushed back toward the side plate 71 against the urging force of the compression spring 70 of the spring unit 15, and the base end portion of the pulling rod 74 is protruded from the through hole 79 of the side plate 71. Thereafter, the grip 81 is attached to the base end portion of the pulling rod 74 and fixed using the spring pin 66. As a result, the ultrasonic sensor unit 2 is manufactured.

  In the ultrasonic sensor unit 2, the measurement pipe 10 is inserted into the pipe arrangement groove 84 of the base 14 in a state where the grip 81 is pulled by hand and the sensor holder 43 is moved toward the side plate 71 against the urging force of the compression spring 70. Is installed. Thereafter, by releasing the hand from the grip 81, the sensor holder 43 is pushed out by the biasing force of the compression spring 70, and the ultrasonic radiation surface 21 of the ultrasonic sensor 12 held by the sensor holder 43 is a straight pipe of the measurement pipe 10. It is pressed against the part 17. As a result, since the straight pipe portion 17 of the measurement pipe 10 is clamped by the pair of ultrasonic sensors 11 and 12, the flow rate of the infusion solution W <b> 1 can be measured by the ultrasonic flow meter 1.

  The inventors created an ultrasonic sensor unit 200 for experiment (see FIG. 8) and confirmed the difference in transmission / reception sensitivity between the pair of ultrasonic sensors 11 and 12 depending on the presence or absence of the rubber sheet 90. As shown in FIG. 8, in the experimental ultrasonic sensor unit 200, the fixed sensor holder 42 formed at one end of the base 14A has the same configuration as the sensor holder 42 of the present embodiment shown in FIG. is there. That is, the sensor holder 42 includes the fixed wall portion 31 in which the storage hole 35 is formed and the sensor pressing plate 41 that presses and fixes the ultrasonic sensor 11 disposed in the storage hole 35 from the base end side. The movable sensor holder 43A includes a movable wall portion 201 and a sensor holding plate 41 that are provided so as to be movable in the longitudinal direction of the base. A storage hole 35 is formed in the movable wall portion 201 of the sensor holder 43 </ b> A similarly to the fixed wall portion 31, and is fixed by the sensor holding plate 41 in a state where the ultrasonic sensor 12 is disposed in the storage hole 35. Yes. Furthermore, the lower end of the movable wall portion 201 is provided with a slide portion (not shown) that is fitted into the two guide grooves 202 provided in the base 14A. In the experimental ultrasonic sensor unit 200, the linear slider 203 is operated to move the sensor holder 43A along the guide groove 202, and a pair of ultrasonic sensors held by the sensor holders 42 and 43A. The 11 and 12 ultrasonic radiation surfaces 21 can be brought into contact with each other. Further, the load applied to each ultrasonic radiation surface 21 can be adjusted by changing the operation amount of the linear slider 203. In the experimental ultrasonic sensor unit 200, the method of attaching the rubber sheet 90 to the sensor holders 42 and 43A is the same as that of the ultrasonic sensor unit 2.

  As shown in FIG. 9, in each of the sensor holders 42 and 43 </ b> A, when the rubber sheet 90 is attached to the ultrasonic radiation surface 21 of the ultrasonic sensors 11 and 12, transmission / reception sensitivity is higher than when the rubber sheet 90 is not attached. It was confirmed that it was increased by about 10 dB. In addition, when the rubber sheet 90 is attached, the higher the load, the more the rubber is crushed and the adhesion is increased, and the thickness of the rubber on the ultrasonic radiation surface 21 is reduced and the ultrasonic attenuation rate is reduced. Was confirmed to rise.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) In the ultrasonic sensor unit 2 of the present embodiment, the rubber sheet 90 has a first region 91 and a second region 92 located on the outer peripheral side thereof, and is located on the center side of the rubber sheet 90. One region 91 is provided so as to cover the radiation surface 21 while being stretched along the ultrasonic radiation surface 21 of the ultrasonic sensors 11 and 12. By providing the rubber sheet 90 in this way, the ultrasonic radiation surface 21 can be reliably adhered to the surface of the measurement pipe 10. In particular, in the present embodiment, since the ultrasonic radiation surface 21 is formed in a convex curved surface shape, the first region 91 of the rubber sheet 90 can be evenly stretched, and the rubber sheet 90 with respect to the ultrasonic radiation surface 21 can be stretched. The close contact state can be maintained well. As a result, problems such as the rubber sheet 90 being torn or air entering between the rubber sheet 90 and the ultrasonic radiation surface 21 can be prevented, and ultrasonic waves are efficiently applied to the infusion solution W1 in the measurement pipe 10. It can be propagated well. Furthermore, since the gap between the inner peripheral surface of the storage holes 35 and 59 and the outer peripheral surface of the ultrasonic sensors 11 and 12 is sealed by the second region 92 on the outer peripheral side of the rubber sheet 90, the ultrasonic sensors 11 and 12. The airtightness in the sensor holders 42 and 43 in which is stored is secured. As a result, the problem that the electrical terminals of the ultrasonic sensors 11 and 12, the connection wiring 28, etc. are corroded or short-circuited in the sensor holders 42 and 43 can be avoided.

  (2) In the ultrasonic sensor unit 2 of the present embodiment, the rubber sheet 90 is provided in an unbonded state and replaceable with respect to the ultrasonic radiation surfaces 21 of the ultrasonic sensors 11 and 12. Therefore, when the rubber sheet 90 is worn due to repeated use of the ultrasonic sensor unit 2, the rubber holder 90 is disassembled and the ultrasonic sensors 11 and 12 are removed from the sensor holders 42 and 43. It can be easily replaced as a consumable part.

  (3) Since the relatively inexpensive rubber sheet 90 is used as the elastic sheet in the ultrasonic sensor unit 2 of the present embodiment, the component cost can be reduced. Further, the rubber sheet 90 has sufficient elasticity, and the second region 92 is sandwiched between the storage holes 35 and 59 and the ultrasonic sensors 11 and 12 and is compressed so that the gap is reliably sealed. Can do. Moreover, since the 1st area | region 91 which covers the ultrasonic radiation surface 21 in the rubber sheet 90 is extended and thinned, the propagation efficiency of an ultrasonic wave can be improved more.

  (4) In the ultrasonic sensor unit 2 of the present embodiment, since the rubber sheet 90 is a self-bonding type sheet, the second region 92 on the outer peripheral side of the rubber sheet 90 is compressed, so that the adhesion is improved. As a result, the gap between the inner peripheral surface of the storage holes 35 and 59 and the outer peripheral surface of the ultrasonic sensors 11 and 12 can be reliably sealed. In addition, the first region 91 on the center side of the rubber sheet 90 is expanded, so that the rubber sheet 90 can be securely adhered along the ultrasonic radiation surface 21.

  (5) In the ultrasonic sensor unit 2 of the present embodiment, in the fixed wall portion 31 of the sensor holder 42 and the holder main body 50 of the sensor holder 43, the small diameter portions 37 and 61 and the large diameter portion 38, Stepped surfaces 39 and 63 are formed at the connection portion with 62. Then, the flange portions 25 of the ultrasonic sensors 11 and 12 are brought into contact with and locked to the step surfaces 39 and 63 from the rear end surfaces 34 and 58 side, whereby the ultrasonic sensors 11 and 12 in the axial direction in the storage holes 35 and 59 are retained. Can be restricted. With this configuration, the tip portions (ultrasonic radiation surfaces 21) of the ultrasonic sensors 11 and 12 can be reliably projected by a predetermined amount from the fixed wall portion 31 and the front end surfaces 33 and 57 of the holder body 50.

  (6) In the ultrasonic sensor unit 2 of the present embodiment, the diameter of the circular rubber sheet 90 is larger than the inner diameters of the small diameter portions 37 and 61 in the storage holes 35 and 59 and the inner diameters of the large diameter portions 38 and 62. Therefore, the rubber sheet 90 can be reliably disposed on the step surfaces 39 and 63 in the storage holes 35 and 59. In this case, since the circular rubber sheet 90 can be accurately positioned with respect to the storage holes 35 and 59, the assembly accuracy of the rubber sheet 90 can be increased. As a result, it is possible to accurately align the center of the ultrasonic radiation surface 21 and the center of the rubber sheet 90, and the rubber sheet 90 with the first region 91 extending uniformly along the ultrasonic radiation surface 21. Can be easily installed.

  (7) In the ultrasonic flowmeter 1 according to the present embodiment, the movable sensor holder 43 that holds the ultrasonic sensor 12 is biased by the spring unit 15, whereby the ultrasonic radiation surface 21 of the ultrasonic sensor 12. Is pressed against the measurement pipe 10, and the measurement pipe 10 is clamped by the pair of ultrasonic sensors 11 and 12. The ultrasonic radiation surfaces 21 of the ultrasonic sensors 11 and 12 are in close contact with the measurement pipe 10 via the rubber sheet 90. For this reason, an ultrasonic wave can be efficiently propagated from the ultrasonic radiation surface 21 of the ultrasonic sensors 11 and 12 into the infusion solution W1 in the measurement pipe 10, and the flow rate of the infusion solution W1 can be reliably measured.

(8) In the ultrasonic flowmeter 1 of the present embodiment, the measurement pipe 10 is provided in the middle of the infusion tube 4 for flowing the infusion solution W1 as a liquid. In this case, the infusion tube 4 is thin, and the measurement pipe 10 connected thereto can be formed thin. For this reason, a small sensor having a diameter of 10 mm can be used as the ultrasonic sensors 11 and 12, and the ultrasonic sensor unit 2 can be formed in a compact manner.
[Second Embodiment]

  Next, a second embodiment embodying the present invention will be described with reference to FIG. In the ultrasonic sensor unit 2 of the above embodiment, the pair of ultrasonic sensors 11 and 12 are arranged to face each other on the upstream side and the downstream side of the straight pipe portion 17 of the measurement pipe 10. On the other hand, as shown in FIG. 10, the pair of ultrasonic sensors 11 and 12 in the ultrasonic sensor unit 2A of the present embodiment are arranged to face each other with the side surface of the measurement pipe 10A interposed therebetween. . This ultrasonic sensor unit 2A is used, for example, in a bubble detection device for detecting bubbles contained in the infusion solution W1.

  Specifically, in the ultrasonic sensor unit 2A of the present embodiment, the configuration of the fixed sensor holder 42 and the movable sensor holder 43 is the same as that of the first embodiment, and the measurement for the base 14 is performed. The installation of the pipe 10A is different from that of the first embodiment.

  Further, in the present embodiment, one ultrasonic sensor 11 in the ultrasonic sensor unit 2A is used as a transmission sensor and the other ultrasonic sensor 12 is used as a reception sensor, and the wiring 28 of each ultrasonic sensor 11, 12 is used. Is connected to a control device (calculation means) (not shown). The control device propagates ultrasonic waves from the transmission ultrasonic sensor 11 into the infusion fluid W1 and detects the presence or absence of bubbles contained in the infusion fluid W1 based on the signal strength of the ultrasonic waves received by the reception ultrasonic sensor 12. .

  Also in the ultrasonic sensor unit 2A of the present embodiment, the same effects as those of the first embodiment can be obtained. In addition, since ultrasonic waves can be efficiently propagated from the ultrasonic radiation surfaces 21 of the ultrasonic sensors 11 and 12 into the infusion solution W1 in the measurement pipe 10A, the detection of bubbles contained in the infusion solution W1 can be accurately and reliably performed. It can be carried out.

  In addition, you may change each embodiment of this invention as follows.

  -Although the ultrasonic sensor unit 2 of the said 1st Embodiment was used for the ultrasonic flowmeter 1 which measures the flow volume of the infusion W1, it is not limited to this, For example, the density | concentration of a liquid is used. You may use for ultrasonic measuring devices, such as an ultrasonic densitometer for measuring. Moreover, although the ultrasonic sensor unit 2A of the second embodiment is used for a bubble detection device for detecting bubbles contained in the infusion solution W1, it is not limited to this and is not limited to the liquid. You may use for ultrasonic measuring devices, such as a foreign material detection apparatus which detects the foreign material which exists, and an ultrasonic concentration meter which measures the density | concentration of the substance which exists in a liquid.

  In the ultrasonic sensor unit 2A of the second embodiment, the presence / absence of bubbles is detected using the pair of ultrasonic sensors 11 and 12, but for example, using one ultrasonic sensor for both transmission and reception, The presence or absence of bubbles may be detected by using reflection.

  In the ultrasonic sensor units 2, 2 </ b> A according to the above embodiments, the ultrasonic radiation surface 21 of one ultrasonic sensor 12 is connected to the measurement pipe 10, using the spring unit 15 that biases the movable sensor holder 43. Although it was set as the structure pressed against 10A, you may comprise using biasing members other than the spring unit 15. FIG. Further, the present invention may be embodied in an ultrasonic sensor unit having a configuration in which the ultrasonic radiation surface 21 of the ultrasonic sensor 11 is pressed against an object by an operator's hand without using an urging member. In the case of using this ultrasonic sensor unit, for example, in a structure in which a plate material such as a decorative panel is fixed via an adhesive layer, the ultrasonic radiation surface 21 of the ultrasonic sensor 11 is pressed against the surface of the plate material to transmit and receive ultrasonic waves. Thus, a non-uniform portion or a peeled portion of the adhesive layer is detected. Even in this ultrasonic sensor unit, the ultrasonic radiation surface 21 can be reliably adhered to the surface of the plate material via the rubber sheet 90. Further, since the inside of the sensor holder is sealed by the rubber sheet 90, it is possible to avoid problems such as corrosion or short-circuiting of the electrical terminals and connection wirings of the ultrasonic sensor 11.

  In the ultrasonic sensor units 2 and 2A of the above embodiments, the sensor holding lid 51 of the sensor holder 43 is fixed by the spring pin 66. However, the present invention is not limited to this. For example, a female screw is formed on the inner peripheral surface on the rear end side in the storage hole 59, a male screw is formed on the outer peripheral surface of the sensor holding lid 51, and the sensor holding lid 51 is fixed in the storage hole 59 by screwing. You may comprise as follows.

  In the ultrasonic sensor units 2 and 2A of the above embodiments, the rubber sheet 90 is a silicon rubber sheet. However, if the elastic sheet has elasticity, a resin made of a fluororesin or an elastomer resin is used. You may use the sheet | seat made from.

  In each of the above embodiments, the ultrasonic radiation surface 21 of the ultrasonic sensors 11 and 12 is a cylindrical radiation surface whose outer edge on the tip side is chamfered into an R surface shape, but is not limited thereto. It is not something. The ultrasonic radiation surfaces 21 of the ultrasonic sensors 11 and 12 may be formed in a convex curved shape, and may be formed in a hemispherical shape, for example.

  Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the respective embodiments described above are listed below.

  (1) In Claim 7 or 8, the measurement pipe is a pipe for measuring a flow rate or a concentration of a liquid, and the pair of ultrasonic sensors face each other on the upstream side and the downstream side of the pipe. Ultrasonic sensor unit characterized by being arranged like this.

  (2) In Claim 9, the pair of ultrasonic sensors is used as a transmission / reception sensor, and the calculation means propagates ultrasonic waves in the forward and reverse directions of the liquid flow by the pair of ultrasonic sensors. Receiving the ultrasonic wave propagating in the forward direction and the ultrasonic wave propagating in the reverse direction, detecting a propagation time difference between the ultrasonic waves, and calculating the flow rate of the liquid based on the propagation time difference, Ultrasonic measuring device.

  (3) In Claim 7 or 8, the measurement pipe is a pipe for detecting bubbles or foreign matters mixed in the liquid, and the pair of ultrasonic sensors sandwiches a side surface of the pipe. An ultrasonic sensor unit, which is arranged to face each other.

  (4) In Claim 9, one of the pair of ultrasonic sensors is used as a transmission sensor and the other is used as a reception sensor, and the calculation means transmits ultrasonic waves from the transmission sensor into the liquid. An ultrasonic flowmeter for detecting the presence or absence of the bubbles or foreign matter based on the signal intensity of the ultrasonic wave propagated and received by the receiving sensor.

  (5) The ultrasonic sensor unit according to any one of claims 1 to 8, wherein the ultrasonic sensor is a small sensor having a diameter of 15 mm or less.

  (6) The ultrasonic sensor unit according to any one of claims 1 to 8, wherein the object is formed using a member harder than the elastic sheet.

  (7) The ultrasonic sensor unit according to any one of claims 1 to 8, wherein the elastic sheet is a sheet having a thickness of 0.1 mm to 2 mm.

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic flowmeter as an ultrasonic measuring device 2, 2A ... Ultrasonic sensor unit 3 ... Measurement control device as a calculation means 4 ... Infusion tube 10, 10A ... Measurement piping 11, 12 ... Ultrasonic Sensor 15 ... Spring unit as biasing means 21 ... Ultrasonic radiation surface 25 ... Flange part 31 ... Fixed wall part 33, 57 ... Front end face 34, 58 ... Rear end face 35, 59 ... Storage hole 37, DESCRIPTION OF SYMBOLS 61 ... Small diameter part 38,62 ... Large diameter part 39,63 ... Step surface 42 ... Fixed type sensor holder 43 ... Movable type sensor holder 50 ... Holder main body as a sensor storage member 51 ... Sensor holding lid as a sensor holding member 90 ... Rubber sheet as elastic sheet 91 ... First region 92 ... Second region W1 ... Infusion as liquid

Claims (10)

An ultrasonic sensor having a convex curved ultrasonic radiation surface at the tip,
A sensor housing member that communicates the front end surface and the rear end surface and is formed with a housing hole in which the ultrasonic sensor is disposed, and suppresses the ultrasonic sensor in the housing hole from the base end side and the ultrasonic sensor. A sensor holder that includes a sensor holding member that fixes the tip in a state of protruding from the front end surface, and the ultrasonic sensor is pressed from the ultrasonic radiation surface with the tip of the ultrasonic sensor pressed against an object. An ultrasonic sensor unit that emits ultrasonic waves,
A first region covering the ultrasonic radiation surface in a state of being stretched along the ultrasonic radiation surface;
An elastic sheet having a second region that is located on the outer peripheral side of the first region and that seals the gap by being sandwiched in the gap between the inner peripheral surface of the storage hole and the outer peripheral surface of the ultrasonic sensor. An ultrasonic sensor unit characterized by that.   The ultrasonic sensor unit according to claim 1, wherein the elastic sheet is provided in a non-adhering state and exchangeable with respect to the ultrasonic radiation surface. The elastic sheet is a rubber sheet;
In the rubber sheet, the second region is compressed in the thickness direction of the rubber sheet, while the first region is expanded in the surface direction of the rubber sheet to be thinner than the second region. The ultrasonic sensor unit according to claim 1 or 2, characterized by the above.   4. The elastic sheet according to claim 1, wherein the elastic sheet is a self-fusing type rubber sheet formed by laminating a pressure-sensitive adhesive layer on a rubber base material, and is in close contact with its own expansion and contraction. The ultrasonic sensor unit described in 1. A flange portion is formed on the base end side of the ultrasonic sensor,
The storage hole is composed of a small-diameter portion and a large-diameter portion located on the rear end face side of the small-diameter portion,
5. A step surface on which the flange portion can be locked from the rear end surface side of the sensor housing member is formed at a connection portion between the small diameter portion and the large diameter portion. The ultrasonic sensor unit according to any one of the above.   The super elastic sheet according to claim 5, wherein the elastic sheet is a circular sheet, and a diameter of the elastic sheet is larger than an inner diameter of the small-diameter portion in the storage hole and smaller than an inner diameter of the large-diameter portion. Sound wave sensor unit. The object is a measurement pipe for flowing a liquid,
A pair of the ultrasonic sensors are arranged so as to face each other with the measurement pipe interposed therebetween,
And a biasing member that applies a biasing force to the sensor holder to press the ultrasonic radiation surface of at least one of the pair of ultrasonic sensors against the measurement pipe and clamp the measurement pipe. The ultrasonic sensor unit according to claim 1, wherein the ultrasonic sensor unit is provided.   The ultrasonic sensor unit according to claim 7, wherein the measurement pipe is provided in the middle of an infusion tube through which the infusion as the liquid flows. The ultrasonic sensor unit according to any one of claims 1 to 8,
An ultrasonic measurement apparatus comprising: an arithmetic unit electrically connected to the ultrasonic sensor and performing arithmetic processing for ultrasonic measurement based on a detection signal of the ultrasonic sensor. A method for manufacturing the ultrasonic sensor unit according to claim 6,
In the sensor storage member, a sheet placement step of positioning and positioning the elastic sheet on the step surface in the storage hole;
The ultrasonic sensor is inserted into the storage hole from the rear end surface side of the sensor storage member, and the elastic body is inserted into the small diameter portion of the storage hole by pressing the rear end surface using the sensor pressing member. The ultrasonic sensor is pushed through a sheet so that the ultrasonic radiation surface covered with the first region of the elastic sheet protrudes from the front end surface of the sensor storage member, and is stored in the second region. A sensor pushing step for sealing a gap between the inner circumferential surface of the hole and the outer circumferential surface of the ultrasonic sensor;
An ultrasonic sensor comprising: a holder forming step of forming the sensor holder by fixing the sensor holding member to the sensor housing member in a state where the flange portion is in contact with the stepped surface. Unit manufacturing method.

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