WO2018051865A1 - Ultrasonic sensor head and ultrasonic detector having said ultrasonic sensor head - Google Patents

Ultrasonic sensor head and ultrasonic detector having said ultrasonic sensor head Download PDF

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Publication number
WO2018051865A1
WO2018051865A1 PCT/JP2017/032152 JP2017032152W WO2018051865A1 WO 2018051865 A1 WO2018051865 A1 WO 2018051865A1 JP 2017032152 W JP2017032152 W JP 2017032152W WO 2018051865 A1 WO2018051865 A1 WO 2018051865A1
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Prior art keywords
ultrasonic
conduit
pair
ultrasonic sensor
sensor head
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PCT/JP2017/032152
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French (fr)
Japanese (ja)
Inventor
浩司 大塚
祐 船橋
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株式会社ジェイ・エム・エス
株式会社鷺宮製作所
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Priority to CN201780055414.6A priority Critical patent/CN109716123B/en
Publication of WO2018051865A1 publication Critical patent/WO2018051865A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/22—Details, e.g. general constructional or apparatus details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/02—Analysing fluids
    • G01N29/032—Analysing fluids by measuring attenuation of acoustic waves
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers
    • H04R17/10—Resonant transducers, i.e. adapted to produce maximum output at a predetermined frequency

Definitions

  • the present invention relates to an ultrasonic sensor head used for detecting bubbles in a liquid flowing through a conduit, and an ultrasonic detector including the ultrasonic sensor head.
  • bubble detectors that detect bubbles are used in medical facilities so that air (bubbles) is not mistakenly injected into a patient's body when performing infusion or blood transfusion.
  • Such a bubble detector has been using ultrasonic waves as one of detection means so that it can be applied to non-transparent drug solution and blood.
  • the transmission / reception surfaces of the sensor head are band-shaped with a narrow width in the liquid flow direction.
  • a technique for forming the film is proposed (see Patent Document 1). By configuring in this way, compared with the configuration in which the transmission / reception surface of the conventional sensor head is formed to have the same width in the vertical and horizontal directions, the ratio of the ultrasonic wave transmitted by the microbubbles is reduced and the ultrasonic wave transmission area is reduced. Increases, the detection sensitivity of microbubbles can be increased.
  • an object of the present invention is to provide an ultrasonic sensor head having high bubble detection sensitivity and few false detections, and an ultrasonic detector including the ultrasonic sensor head.
  • the present invention is a pair of ultrasonic sensor heads arranged opposite to each other across a conduit through which a liquid flows, wherein one of the pair of ultrasonic sensor heads faces the conduit.
  • the other of the pair of ultrasonic sensor heads includes a second vibration surface facing the conduit, and the width of the second vibration surface in the liquid flow direction is the first vibration surface.
  • a pair of ultrasonic sensors that are smaller than the width of the vibration surface, and one of the first vibration surface and the second vibration surface is used as an ultrasonic wave transmission surface and the other is used as an ultrasonic wave reception surface Regarding the head.
  • the first vibration surface is used as an ultrasonic wave transmission surface and the second vibration surface is used as an ultrasonic wave reception surface.
  • the pair of ultrasonic sensor heads are disposed so as to come into contact with the conduit at the first vibration surface and the second vibration surface, and the first vibration surface is perpendicular to the flow direction of the liquid. It is preferable that the cross-sectional shape cut by a smooth surface is formed in a concave curve shape or a convex curve shape.
  • the conduit has flexibility
  • the second vibration surface has a cross-sectional shape cut by a plane parallel to the ultrasonic wave transmission / reception direction and the liquid flow direction in a convex curve shape or a straight line shape. Preferably formed.
  • the present invention also relates to an ultrasonic detector that includes any one of the above-described pair of ultrasonic sensor heads and detects bubbles in the liquid flowing through the conduit.
  • an ultrasonic sensor head having high bubble detection sensitivity and few false detections
  • an ultrasonic detector including the ultrasonic sensor head.
  • FIG. 1B is a YY cross-sectional view of FIG. 1A. It is a block diagram which shows embodiment of the ultrasonic sensor head of this invention, and is the figure which looked at the 1st sensor head from the 1st vibration surface side. It is a block diagram which shows embodiment of the ultrasonic sensor head of this invention, and is the figure which looked at the 2nd sensor head from the 2nd vibration surface side.
  • FIG. 2B is a YY sectional view of FIG. 2A. It is a figure which shows 1st Embodiment of the ultrasonic sensor head of this invention, and is the figure which looked at the 1st sensor head from the 1st vibration surface side. It is a figure which shows 1st Embodiment of the ultrasonic sensor head of this invention, and is the figure which looked at the 2nd sensor head from the 2nd vibration surface side.
  • FIG. 3B is a YY cross-sectional view of FIG. 3A. It is a figure which shows 2nd Embodiment of the ultrasonic sensor head of this invention, and is the figure which looked at the 1st sensor head from the 1st vibration surface side. It is a figure which shows 2nd Embodiment of the ultrasonic sensor head of this invention, and is the figure which looked at the 2nd sensor head from the 2nd vibration surface side.
  • FIG. 5B is a YY sectional view of FIG. 5A.
  • the pair of ultrasonic sensor heads 1 includes a first sensor head 10 and a second sensor head 20, and are disposed to face each other with a conduit 30 interposed therebetween.
  • the first sensor head 10 includes an ultrasonic transmission body 110 on which a first vibration surface 111 is formed, and an ultrasonic transducer 120 that converts an electric signal and vibration.
  • the second sensor head 20 includes an ultrasonic transmission body 210 on which a second vibration surface 211 is formed, and an ultrasonic transducer 220 that converts an electric signal and vibration.
  • the ultrasonic transmission bodies 110 and 210 transmit ultrasonic waves between the ultrasonic transducers (120, 220) and the vibration surfaces (111, 211).
  • the ultrasonic transmission bodies 110 and 210 are formed of a resin such as acrylic, hard polyvinyl chloride, or modified polyphenylene ether.
  • the ultrasonic transmission bodies 110 and 210 are formed of an acrylic resin.
  • the ultrasonic transmission bodies 110 and 210 not only transmit ultrasonic waves, but also, for example, as described in the first embodiment and the second embodiment described later, the vibration surface has a concave curved surface shape or a convex curved surface shape. By doing so, it is also possible to function as an acoustic lens for focusing or diffusing ultrasonic waves.
  • the first vibration surface 111 and the second vibration surface 211 are formed on the ultrasonic transmission bodies 110 and 210 so as to face the side surfaces of the conduit 30, respectively, and contact the conduit 30 to transmit ultrasonic waves.
  • the first vibration surface 111 is formed in a circular shape as shown in FIG. 1C
  • the second vibration surface 211 is formed in a rectangular shape as shown in FIG. 1D.
  • the width w2 of the second vibrating surface 211 is formed smaller than the width w1 of the first vibrating surface 111 in the liquid flow direction (y direction).
  • the ratio of the width w2 to the width w1 is preferably about 0.1 to 0.7.
  • the ratio is larger than 0.1, the area of the second vibration surface 211 is increased, the intensity of transmission / reception of ultrasonic waves is increased, and the reception voltage is easily stabilized, which is preferable.
  • it is preferable that the ratio is smaller than 0.7 because the width w2 is reduced and sensitivity capable of detecting microbubbles can be obtained.
  • first sensor head 10 and the second sensor head 20 are arranged to face each other, since either one of the transmission surface and the reception surface is wide in the liquid flow direction (y direction), a precise position is provided. Even without matching, transmission / reception can be reliably performed.
  • the width h1 and second of the first vibrating surface 111 is configured to have the same size.
  • the width be equal to the inner diameter of the conduit 30 in the z direction.
  • the width h1 and the width h2 may be at least about half the inner diameter of the conduit 30 so that the ultrasonic wave is transmitted through the central portion of the conduit 30. .
  • the width h1 and the width h2 are preferably set to be equal to the inner diameter of the conduit 30 in the z direction.
  • the ultrasonic transducers 120 and 220 disk-shaped piezoelectric elements are used, and electrodes (not shown) are attached to both surfaces of the transducers to convert input electric signals into mechanical vibrations and transmit them. The generated mechanical vibration can be converted into an electrical signal and output.
  • the ultrasonic transducers 120 and 220 are embedded and disposed inside the ultrasonic transmission bodies 110 and 210, respectively.
  • piezoelectric ceramics such as lead zirconate titanate, piezoelectric thin films such as zinc oxide, piezoelectric polymer films such as vinylidene fluoride, and the like are applicable.
  • lead zirconate titanate is used as the material of the piezoelectric element, and silver and platinum are used as the electrodes.
  • the conduit 30 is formed of a flexible tube such as soft vinyl chloride (PVC) or silicon (Si).
  • PVC soft vinyl chloride
  • Si silicon
  • the outer diameter is 5.5 to 6.5 mm and the inner diameter is 3. The one having 5 to 4.5 mm is used.
  • the first sensor head 10 and the second sensor head 20 constituting the pair of ultrasonic sensor heads 1 described above can be used as a transmission head and a reception head of an ultrasonic detector, respectively.
  • a configuration in which the first sensor head is used as a transmission head and the second sensor head is used as a reception head will be described in the first embodiment, and the second sensor head is used as a transmission head.
  • a configuration in which is used as a receiving head will be described.
  • FIG. 2A shows a pair of ultrasonic sensor heads 1A arranged to face each other with a conduit interposed therebetween
  • FIG. 2B is a YY sectional view of FIG. 2A.
  • the pair of ultrasonic sensor heads 1A includes a first sensor head 10A as a transmission head and a second sensor head 20A as a reception head, and is a tube (outer diameter 5.5 mm) as a conduit 30. And an inner diameter of 3.5 mm).
  • the first sensor head 10A includes an ultrasonic transmission body 110A on which a first vibration surface 111A serving as a transmission surface is formed, and an ultrasonic transducer 120 that converts an electric signal and vibration.
  • the second sensor head 20A includes an ultrasonic transmission body 210A on which a second vibration surface 211A serving as a reception surface is formed, and an ultrasonic transducer 220 that converts an electric signal and vibration.
  • the ultrasonic transmission bodies 110A and 210A are configured in the same manner as the ultrasonic transmission bodies 110 and 210 except that the shapes of the respective vibration surfaces are different.
  • the ultrasonic wave can be efficiently transmitted to the liquid in the conduit 30 and the directivity of the ultrasonic wave is improved. Furthermore, the ultrasonic wave is easily focused by the lens effect on the first vibration surface 111A formed in a concave curved surface. Therefore, the transmission intensity of ultrasonic waves can be improved.
  • the second vibrating surface 211A is a cross section cut by a plane (xy plane) parallel to the ultrasonic transmission / reception direction (x direction) and the liquid flow direction (y direction).
  • the shape is formed in a convex curve shape with respect to the side surface of the conduit 30 having flexibility.
  • the width w2A of the second vibrating surface 211A (receiving surface) is small in the liquid flow direction (y direction), the proportion of the microbubbles in the projection surface on the receiving surface increases. Therefore, the rate at which the ultrasonic waves that pass through the liquid are reflected by the microbubbles and the ultrasonic waves that reach the receiving surface are attenuated increases, and the microbubbles can be detected with high sensitivity.
  • the pair of ultrasonic sensor heads 1A according to the first embodiment has the following effects.
  • the width w2A of the second vibrating surface 211A (receiving surface) is smaller than the width w1A of the first vibrating surface 111A (transmitting surface).
  • the first vibration surface 111A (transmission surface) is formed in a concave curve shape so that a cross-sectional shape cut by a surface perpendicular to the liquid flow direction (y direction) is along the side surface of the conduit 30.
  • pipe 30 and a transmission surface improves, and also both contact areas can be enlarged, Therefore An ultrasonic wave can be efficiently transmitted to the liquid in the conduit
  • the transmission surface is large, the directivity of ultrasonic waves is improved. Further, since the transmission surface is formed in a concave curved surface, the ultrasonic wave is focused by the lens effect, and the directivity is further improved. Therefore, the transmission intensity of the ultrasonic wave can be increased, and the output voltage in the ultrasonic detector is stabilized.
  • the conduit 30 is flexible, and the second vibrating surface 211A (receiving surface) is a surface (xy) parallel to the ultrasonic transmission / reception direction (x direction) and the liquid flow direction (y direction).
  • a cross-sectional shape cut by a plane is formed in a convex curve shape.
  • FIG. 3A shows a pair of ultrasonic sensor heads 1B arranged to face each other with a conduit interposed therebetween, and FIG. 3B is a YY sectional view of FIG. 3A.
  • the pair of ultrasonic sensor heads 1B includes a second sensor head 20B (20A) as a transmission head and a first sensor head 10B (10A) as a reception head, and a tube as a conduit 30 They are arranged facing each other with an outer diameter of 5.5 mm and an inner diameter of 3.5 mm.
  • the first sensor head 10A used as the transmission head in the first embodiment is used as the reception head (first sensor head 10B), and the second sensor head 10A used as the reception head in the first embodiment is used.
  • the difference from the first embodiment is that the sensor head 20A is used as a transmission head (second sensor head 20B). Since the shape of each vibration surface is the same as that of the first embodiment, description thereof is omitted.
  • the second vibration surface 211B (211A) is formed in a convex curve shape on the ultrasonic transmission body 210B (210A). More specifically, as shown in FIG. 3A, the second vibration surface 211B (211A) is a surface (xy plane) parallel to the ultrasonic wave transmission / reception direction (x direction) and the liquid flow direction (y direction).
  • the cut cross-sectional shape is formed in a convex curve shape with respect to the side surface of the conduit 30 having flexibility.
  • the first vibration surface 111B (111A) is formed in a concave curved surface on the ultrasonic transmission body 110B as shown in FIG. 3B. More specifically, the first vibration surface 111 ⁇ / b> B (111 ⁇ / b> A) is formed in a concave curve shape so that a cross-sectional shape cut by a surface perpendicular to the liquid flow direction (y direction) is along the side surface of the conduit 30. With this configuration, the adhesion between the side surface of the conduit 30 and the first vibrating surface 111B (111A) is improved, so that the ultrasonic wave that has passed through the liquid in the conduit 30 can be efficiently transmitted. Therefore, the reception intensity can be increased.
  • FIG. 4A is a diagram illustrating a projection surface of microbubbles when the directivity of a transmission wave from the second vibration surface 211B (transmission surface) is high
  • FIG. 4B illustrates the second vibration surface 211B (transmission surface).
  • FIG. 9 is a diagram for explaining a projection surface of microbubbles when the directivity of a transmission wave from) is low.
  • the ultrasonic wave transmitted from the transmission side is of high directivity, in a portion of the receiving surface (hatched portion P A), to receive transmission waves.
  • the projection surface of the microbubbles in the entire receiving surface the proportion is considered to be negligible, with respect to the hatched portions P A which receives the transmission wave at the receiving side, the ratio of the projection surface of the microbubbles occupied It can be said to be large enough to be detected. Therefore, the ultrasonic waves transmitted through the liquid is reflected by microbubbles, the ultrasonic wave reaches the hatched portion P A which receives the transmission wave of the reception surface is the ratio of attenuation is large, it can detect microbubbles with high sensitivity.
  • the ultrasonic wave transmitted from the transmitting side is low in directivity, for example, when the directivity of the transmission wave due to a small width w2 B transmission side is lowered, the transmission surface convex curved Therefore, it may be possible that the ultrasonic wave is easily diffused by the lens effect.
  • FIG. 4B when the ultrasonic wave transmitted from the transmission surface has low directivity, the transmission wave is received in most of the reception surface (shaded portion P B ). Since the receiving surface is wider in the liquid flow direction (y direction) than the transmitting surface, even if the ultrasonic wave that has passed through the liquid diffuses along the y direction, it is received at the hatched portion P B of the receiving surface. Is possible.
  • microbubbles When microbubbles exist, the microbubbles are enlarged and projected in the y direction along with the diffusion of ultrasonic waves on the receiving surface. Therefore, the ultrasonic waves transmitted through the liquid is reflected by microbubbles, since ultrasonic waves spread in the y-direction to reach the hatched portion P B which receives the transmission wave of the reception surface proportion to attenuation increases, high microbubbles Can be detected with sensitivity.
  • the width w1B of the first vibrating surface 111B (receiving surface) is smaller than the width w2B of the second vibrating surface 211B (transmitting surface).
  • the first vibrating surface 111B (receiving surface) is formed in a concave curve shape so that a cross-sectional shape cut by a surface perpendicular to the liquid flow direction (y direction) is along the side surface of the conduit 30.
  • the conduit 30 has flexibility, and the second vibration surface 211B (transmission surface) is a surface (xy) parallel to the ultrasonic transmission / reception direction (x direction) and the liquid flow direction (y direction).
  • a cross-sectional shape cut by a plane is formed in a convex curve shape.
  • the width w1B of the first vibration surface 111B (reception surface) is smaller than the width w2B of the second vibration surface 211 (transmission surface).
  • the ultrasonic wave when the directivity of the ultrasonic wave is low, when the ultrasonic wave passing through the liquid is reflected by the microbubbles, the ultrasonic wave diffuses in the y direction reaching the most part (the hatched part P B ) that receives the transmission wave on the receiving surface. Since the rate at which ultrasonic waves are attenuated increases, microbubbles can be detected with high sensitivity.
  • a bubble detection experiment was performed using the pair of ultrasonic sensor heads described in the first and second embodiments and the ultrasonic sensor head corresponding to the configuration of the conventional technology.
  • the bubble detection experiment was performed using a hemodialysis machine (not shown).
  • the hemodialysis apparatus includes a tube having flexibility as the conduit 30 and an ultrasonic detector having the ultrasonic sensor head 1A described in the first embodiment.
  • a flexible vinyl chloride tube having an outer diameter of 5.5 mm and an inner diameter of 3.5 mm was prepared.
  • approximately 36 ° C. water heated to a temperature similar to that of body fluid was allowed to flow through the tube at a flow rate of 250 mL / min.
  • a pair of ultrasonic sensor heads 1 ⁇ / b> A were arranged facing each other so as to sandwich the tube.
  • a micro-syringe is used to inject 0.3 ⁇ L microbubbles (bubble diameter is approximately 0.83 mm) with water flowing in the tube, and the change in the bubble detection rate and voltage is confirmed with a hemodialyzer.
  • An air bubble detection experiment was conducted. This was repeated 30 times to evaluate the bubble detection rate and the voltage stability.
  • Example 2 Using the pair of ultrasonic sensor heads 1B described in the second embodiment as the ultrasonic sensor head, a bubble detection experiment was performed in the same manner as in Example 1.
  • Example 1 As an ultrasonic sensor head, a bubble detection experiment was performed in the same manner as in Example 1 using a pair of ultrasonic sensor heads including the first sensor head 10A described in the first embodiment.
  • Example 2 As an ultrasonic sensor head, a bubble detection experiment was performed in the same manner as in Example 1 by using a pair of ultrasonic sensor heads including the second sensor head 20A described in the first embodiment. The experimental results of Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 1.
  • the bubble detection rate in Examples 1 and 2 was significantly improved as compared with Comparative Example 1.
  • the bubble detection rate was 93% and 87%.
  • the detection rate is estimated to be 100%.
  • Examples 1 and 2 showed that the received voltage change was stabilized at ⁇ 0.1 V. Therefore, the ultrasonic detector equipped with the pair of ultrasonic sensor heads of the present invention is erroneous. Generation of detection can be suppressed. Therefore, it is not necessary to perform complicated circuit design in hardware necessary for preventing erroneous detection, or to devise an algorithm in software, and the configuration of the ultrasonic detector can be simplified.
  • the first vibrating surface 111 according to the embodiment has a circular shape as an example, but may be an elliptical shape or a rectangular shape.
  • the 1st vibration surface was formed in the concave curved surface shape in the ultrasonic transmission body, it is not restricted to this. That is, as shown in FIGS. 5A and 5B, the first vibration surface 111C may be formed in a convex curved surface on the ultrasonic transmission body 110C. In the first embodiment, the second vibration surface is formed in a convex curved surface on the ultrasonic transmission body, but the present invention is not limited to this. That is, as shown in FIGS. 5A and 5B, the second vibration surface 211C may be formed in a planar shape (linear shape) on the ultrasonic transmission body 210C.
  • the contact-type configuration in which the ultrasonic sensor head is in contact with the conduit on the vibration surface and transmits ultrasonic waves is shown, but the present invention is also applied to a non-contact type ultrasonic sensor head. The concept of is applicable.
  • a flexible tube is shown as an example of the conduit.
  • the present invention is not limited to this.
  • the concept of the present invention is applicable not only to medical and industrial resin tubes but also to metal tubes, pipes and the like.
  • an ultrasonic detector including the ultrasonic sensor head of the present invention can be applied, a hemodialysis apparatus has been shown, but the present invention is not limited thereto.
  • the present invention can be applied to a blood vessel or a medical device connected to an infusion circuit in which the presence of air bubbles is a problem, and can be widely applied to fields where air bubbles need to be detected outside the medical field.

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  • Life Sciences & Earth Sciences (AREA)
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Abstract

Provided are an ultrasonic sensor head and an ultrasonic detector having the ultrasonic sensor head, which have a high detection sensitivity and few false detections of air bubbles. The present invention pertains to a pair of ultrasonic sensor heads (1) that are disposed facing each other with a conduit (30), through which a liquid flows, interposed therebetween, and that can transceive ultrasonic waves. One (10) of the pair of ultrasonic sensor heads (1) is provided with a first oscillation surface (111) facing the conduit (30); and the other (20) of the pair of ultrasonic sensor heads (1) is provided with a second oscillation surface (211) facing the conduit (30). The width of the second oscillation surface (211) in the liquid flow direction is smaller than the width of the first oscillating surface (111), and one among the first oscillating surface (111) and the second oscillation surface (211) is used as an ultrasonic wave transmitting surface, and the other is used as an ultrasonic wave receiving surface.

Description

超音波センサヘッド及び該超音波センサヘッドを備える超音波検出器Ultrasonic sensor head and ultrasonic detector provided with the ultrasonic sensor head
　本発明は、導管を流れる液体中の気泡を検出するために用いられる超音波センサヘッド及び該超音波センサヘッドを備える超音波検出器に関する。 The present invention relates to an ultrasonic sensor head used for detecting bubbles in a liquid flowing through a conduit, and an ultrasonic detector including the ultrasonic sensor head.
　従来、医療施設において、輸液・輸血等を行う際に誤って患者の体内に空気（気泡）を注入しないように、気泡を検出する気泡検出器が利用されている。このような気泡検出器は、透明でない薬液や血液にも適用可能なように、検出手段の１つとして超音波が利用されてきた。 2. Description of the Related Art Conventionally, bubble detectors that detect bubbles are used in medical facilities so that air (bubbles) is not mistakenly injected into a patient's body when performing infusion or blood transfusion. Such a bubble detector has been using ultrasonic waves as one of detection means so that it can be applied to non-transparent drug solution and blood.
　例えば、微小気泡を検出する超音波検出器として、液体が流れる導管を挟んで対向して配置される一対の超音波センサヘッドにおいて、センサヘッドの送受信面を液体の流れ方向の幅を狭くした帯状に形成する技術が提案されている（特許文献１参照）。このように構成することで、従来のセンサヘッドの送受信面が縦横同等の幅に形成される構成に比べ、超音波が伝達される面積が小さくなり、微小気泡による超音波の強度が減少する割合が大きくなるため、微小気泡の検出感度を高められる。 For example, as an ultrasonic detector for detecting microbubbles, in a pair of ultrasonic sensor heads arranged to face each other across a conduit through which a liquid flows, the transmission / reception surfaces of the sensor head are band-shaped with a narrow width in the liquid flow direction. A technique for forming the film is proposed (see Patent Document 1). By configuring in this way, compared with the configuration in which the transmission / reception surface of the conventional sensor head is formed to have the same width in the vertical and horizontal directions, the ratio of the ultrasonic wave transmitted by the microbubbles is reduced and the ultrasonic wave transmission area is reduced. Increases, the detection sensitivity of microbubbles can be increased.
実公平５－２９７１７号公報Japanese Utility Model Publication No. 5-29717
　上述のように、センサヘッドの送受信面について液体の流れ方向の幅を狭く形成して、気泡の検出感度を高感度にした場合、送受信面が小さいため伝達される超音波が弱く受信電圧が小さくなり、気泡の有無判定の電圧差も小さい。そのため、導管の材質や種類、導管とセンサヘッドとの接触状態、温度や湿度等の周囲環境の変化によって受信電圧が変化したり不安定となったりして、誤検知を発生させやすい。
　このような誤検知を発生させないために、一般的に、超音波検出器には、ハードウェアにおいては複雑な回路設計が、ソフトウェアにおいてはアルゴリズムの工夫等が必要となる。 As described above, when the width of the flow direction of the liquid is formed narrow on the transmission / reception surface of the sensor head and the bubble detection sensitivity is made high, the transmitted ultrasonic wave is weak and the reception voltage is small because the transmission / reception surface is small. Thus, the voltage difference in the presence / absence determination of bubbles is small. For this reason, the received voltage changes or becomes unstable due to changes in the material and type of the conduit, the contact state between the conduit and the sensor head, and the surrounding environment such as temperature and humidity.
In order to prevent such erroneous detection from occurring, in general, an ultrasonic detector requires a complicated circuit design in hardware and an ingenuity of an algorithm in software.
　従って、本発明は、気泡の検出感度が高く、誤検知が少ない超音波センサヘッド及び該超音波センサヘッドを備える超音波検出器を提供することを目的とする。 Therefore, an object of the present invention is to provide an ultrasonic sensor head having high bubble detection sensitivity and few false detections, and an ultrasonic detector including the ultrasonic sensor head.
　本発明は、液体が流れる導管を挟んで対向配置され、超音波を送受信可能な一対の超音波センサヘッドであって、前記一対の超音波センサヘッドの一方は、前記導管に面する第１の振動面を備え、前記一対の超音波センサヘッドの他方は、前記導管に面する第２の振動面を備え、前記液体の流れ方向について、前記第２の振動面の幅は、前記第１の振動面の幅よりも小さく、前記第１の振動面及び前記第２の振動面のいずれか一方が超音波の送信面として用いられ、他方が超音波の受信面として用いられる一対の超音波センサヘッドに関する。 The present invention is a pair of ultrasonic sensor heads arranged opposite to each other across a conduit through which a liquid flows, wherein one of the pair of ultrasonic sensor heads faces the conduit. The other of the pair of ultrasonic sensor heads includes a second vibration surface facing the conduit, and the width of the second vibration surface in the liquid flow direction is the first vibration surface. A pair of ultrasonic sensors that are smaller than the width of the vibration surface, and one of the first vibration surface and the second vibration surface is used as an ultrasonic wave transmission surface and the other is used as an ultrasonic wave reception surface Regarding the head.
　また、前記第１の振動面が超音波の送信面として用いられ、前記第２の振動面が超音波の受信面として用いられることが好ましい。 Further, it is preferable that the first vibration surface is used as an ultrasonic wave transmission surface and the second vibration surface is used as an ultrasonic wave reception surface.
　また、前記一対の超音波センサヘッドは、前記第１の振動面及び前記第２の振動面において前記導管と接触するように配置され、前記第１の振動面は、前記液体の流れ方向に垂直な面で切った断面形状が凹曲線状又は凸曲線状に形成されることが好ましい。 The pair of ultrasonic sensor heads are disposed so as to come into contact with the conduit at the first vibration surface and the second vibration surface, and the first vibration surface is perpendicular to the flow direction of the liquid. It is preferable that the cross-sectional shape cut by a smooth surface is formed in a concave curve shape or a convex curve shape.
　また、前記導管は可撓性を備えており、前記第２の振動面は、前記超音波の送受信方向及び前記液体の流れ方向に平行な面で切った断面形状が凸曲線状又は直線状に形成されることが好ましい。 Further, the conduit has flexibility, and the second vibration surface has a cross-sectional shape cut by a plane parallel to the ultrasonic wave transmission / reception direction and the liquid flow direction in a convex curve shape or a straight line shape. Preferably formed.
　また、本発明は、上述のいずれかの一対の超音波センサヘッドを備え、前記導管を流れる液体中の気泡を検出する超音波検出器に関する。 The present invention also relates to an ultrasonic detector that includes any one of the above-described pair of ultrasonic sensor heads and detects bubbles in the liquid flowing through the conduit.
　本発明によれば、気泡の検出感度が高く、誤検知が少ない超音波センサヘッド及び該超音波センサヘッドを備える超音波検出器を提供できる。 According to the present invention, it is possible to provide an ultrasonic sensor head having high bubble detection sensitivity and few false detections, and an ultrasonic detector including the ultrasonic sensor head.
本発明の超音波センサヘッドの実施形態を示す構成図であり、導管を挟んで対向配置される一対の超音波センサヘッドを示す図である。It is a block diagram which shows embodiment of the ultrasonic sensor head of this invention, and is a figure which shows a pair of ultrasonic sensor head arrange | positioned opposingly on both sides of a conduit | pipe. 図１ＡのＹ－Ｙ断面図である。FIG. 1B is a YY cross-sectional view of FIG. 1A. 本発明の超音波センサヘッドの実施形態を示す構成図であり、第１のセンサヘッドを第１の振動面側から見た図である。It is a block diagram which shows embodiment of the ultrasonic sensor head of this invention, and is the figure which looked at the 1st sensor head from the 1st vibration surface side. 本発明の超音波センサヘッドの実施形態を示す構成図であり、第２のセンサヘッドを第２の振動面側から見た図である。It is a block diagram which shows embodiment of the ultrasonic sensor head of this invention, and is the figure which looked at the 2nd sensor head from the 2nd vibration surface side. 本発明の超音波センサヘッドの第１実施形態を示す図であり、導管を挟んで対向配置される一対の超音波センサヘッド１Ａを示す図である。It is a figure which shows 1st Embodiment of the ultrasonic sensor head of this invention, and is a figure which shows a pair of ultrasonic sensor head 1A arrange | positioned on both sides of a conduit | pipe. 図２ＡのＹ－Ｙ断面図である。FIG. 2B is a YY sectional view of FIG. 2A. 本発明の超音波センサヘッドの第１実施形態を示す図であり、第１のセンサヘッドを第１の振動面側から見た図である。It is a figure which shows 1st Embodiment of the ultrasonic sensor head of this invention, and is the figure which looked at the 1st sensor head from the 1st vibration surface side. 本発明の超音波センサヘッドの第１実施形態を示す図であり、第２のセンサヘッドを第２の振動面側から見た図である。It is a figure which shows 1st Embodiment of the ultrasonic sensor head of this invention, and is the figure which looked at the 2nd sensor head from the 2nd vibration surface side. 本発明の超音波センサヘッドの第２実施形態を示す図であり、導管を挟んで対向配置される一対の超音波センサヘッド１Ｂを示す図である。It is a figure which shows 2nd Embodiment of the ultrasonic sensor head of this invention, and is a figure which shows a pair of ultrasonic sensor head 1B arrange | positioned on both sides of a conduit | pipe. 図３ＡのＹ－Ｙ断面図である。FIG. 3B is a YY cross-sectional view of FIG. 3A. 本発明の超音波センサヘッドの第２実施形態を示す図であり、第１のセンサヘッドを第１の振動面側から見た図である。It is a figure which shows 2nd Embodiment of the ultrasonic sensor head of this invention, and is the figure which looked at the 1st sensor head from the 1st vibration surface side. 本発明の超音波センサヘッドの第２実施形態を示す図であり、第２のセンサヘッドを第２の振動面側から見た図である。It is a figure which shows 2nd Embodiment of the ultrasonic sensor head of this invention, and is the figure which looked at the 2nd sensor head from the 2nd vibration surface side. 本発明の第２実施形態において、第２の振動面２１１Ｂ（送信面）からの送信波の指向性が高い場合の微小気泡の投影面を説明する図である。In 2nd Embodiment of this invention, it is a figure explaining the projection surface of a microbubble in case the directivity of the transmission wave from the 2nd vibration surface 211B (transmission surface) is high. 本発明の第２実施形態において、第２の振動面２１１Ｂ（送信面）からの送信波の指向性が低い場合の微小気泡の投影面を説明する図である。In 2nd Embodiment of this invention, it is a figure explaining the projection surface of a microbubble in case the directivity of the transmission wave from the 2nd vibration surface 211B (transmission surface) is low. 本発明の超音波センサヘッドの変形例を示す図であり、導管を挟んで対向配置される一対の超音波センサヘッド１Ｃを示す図である。It is a figure which shows the modification of the ultrasonic sensor head of this invention, and is a figure which shows a pair of ultrasonic sensor head 1C arrange | positioned on both sides of a conduit | pipe. 図５ＡのＹ－Ｙ断面図である。FIG. 5B is a YY sectional view of FIG. 5A.
　以下、本発明の一対の超音波センサヘッドの実施形態について図１Ａ～図１Ｄを参照して説明する。
　一対の超音波センサヘッド１は、第１のセンサヘッド１０と、第２のセンサヘッド２０と、を含んで構成され、導管３０を挟んで対向して配置される。 Hereinafter, embodiments of a pair of ultrasonic sensor heads according to the present invention will be described with reference to FIGS. 1A to 1D.
The pair of ultrasonic sensor heads 1 includes a first sensor head 10 and a second sensor head 20, and are disposed to face each other with a conduit 30 interposed therebetween.
　第１のセンサヘッド１０は、第１の振動面１１１が形成された超音波伝達体１１０と、電気信号と振動とを変換する超音波振動子１２０と、を備える。
　第２のセンサヘッド２０は、第２の振動面２１１が形成された超音波伝達体２１０と、電気信号と振動とを変換する超音波振動子２２０と、を備える。 The first sensor head 10 includes an ultrasonic transmission body 110 on which a first vibration surface 111 is formed, and an ultrasonic transducer 120 that converts an electric signal and vibration.
The second sensor head 20 includes an ultrasonic transmission body 210 on which a second vibration surface 211 is formed, and an ultrasonic transducer 220 that converts an electric signal and vibration.
　超音波伝達体１１０及び２１０は、超音波振動子（１２０、２２０）と振動面（１１１、２１１）との間で超音波を伝達する。超音波伝達体１１０，２１０は、アクリル、硬質ポリ塩化ビニル、変性ポリフェニレンエーテル等の樹脂により形成される。本実施形態では、超音波伝達体１１０，２１０は、アクリル樹脂により形成される。
　また、超音波伝達体１１０及び２１０は、単に超音波を伝達するだけでなく、例えば後述の第１実施形態及び第２実施形態で説明するように、振動面を凹曲面状又は凸曲面状とすることで、超音波を集束又は拡散させる音響レンズとして機能させることも可能である。 The ultrasonic transmission bodies 110 and 210 transmit ultrasonic waves between the ultrasonic transducers (120, 220) and the vibration surfaces (111, 211). The ultrasonic transmission bodies 110 and 210 are formed of a resin such as acrylic, hard polyvinyl chloride, or modified polyphenylene ether. In this embodiment, the ultrasonic transmission bodies 110 and 210 are formed of an acrylic resin.
Further, the ultrasonic transmission bodies 110 and 210 not only transmit ultrasonic waves, but also, for example, as described in the first embodiment and the second embodiment described later, the vibration surface has a concave curved surface shape or a convex curved surface shape. By doing so, it is also possible to function as an acoustic lens for focusing or diffusing ultrasonic waves.
　第１の振動面１１１及び第２の振動面２１１は、それぞれ導管３０の側面に面するように超音波伝達体１１０及び２１０に形成されており、導管３０に接触して超音波を伝達する。第１の振動面１１１は、図１Ｃに示すように円形に形成され、第２の振動面２１１は、図１Ｄに示すように矩形状に形成される。 The first vibration surface 111 and the second vibration surface 211 are formed on the ultrasonic transmission bodies 110 and 210 so as to face the side surfaces of the conduit 30, respectively, and contact the conduit 30 to transmit ultrasonic waves. The first vibration surface 111 is formed in a circular shape as shown in FIG. 1C, and the second vibration surface 211 is formed in a rectangular shape as shown in FIG. 1D.
　図１Ｃ及び図１Ｄに示すように、液体の流れ方向（ｙ方向）について、第２の振動面２１１の幅ｗ２は、第１の振動面１１１の幅ｗ１よりも小さく形成される。具体的には幅ｗ１に対する幅ｗ２の割合は、０．１～０．７程度であることが望ましい。割合が０．１より大きいと、第２の振動面２１１の面積が大きくなって超音波の送受信の強度が大きくなり、受信電圧が安定しやすいため好ましい。また、割合が０．７より小さいと、幅ｗ２が小さくなって微小気泡を検出可能な感度を得られるため好ましい。
　また、第１のセンサヘッド１０及び第２のセンサヘッド２０を対向して配置する際に、液体の流れ方向（ｙ方向）について、送信面及び受信面のいずれか一方が広いので、精密な位置合わせを行わなくても、確実に送受信が可能となる。 As shown in FIGS. 1C and 1D, the width w2 of the second vibrating surface 211 is formed smaller than the width w1 of the first vibrating surface 111 in the liquid flow direction (y direction). Specifically, the ratio of the width w2 to the width w1 is preferably about 0.1 to 0.7. When the ratio is larger than 0.1, the area of the second vibration surface 211 is increased, the intensity of transmission / reception of ultrasonic waves is increased, and the reception voltage is easily stabilized, which is preferable. Moreover, it is preferable that the ratio is smaller than 0.7 because the width w2 is reduced and sensitivity capable of detecting microbubbles can be obtained.
In addition, when the first sensor head 10 and the second sensor head 20 are arranged to face each other, since either one of the transmission surface and the reception surface is wide in the liquid flow direction (y direction), a precise position is provided. Even without matching, transmission / reception can be reliably performed.
　図１Ｂ～図１Ｄに示すように、液体の流れ方向（ｙ方向）及び超音波の送信方向（ｘ方向）に垂直なｚ方向について、一例として、第１の振動面１１１の幅ｈ１及び第２の振動面２１１の幅ｈ２は同等の大きさを有するように構成した。
　その幅ｈ１及び幅ｈ２について、粘性が小さい液体中の気泡を検出する場合は、可撓性を有する導管３０が第１の振動面１１１及び第２の振動面２１１で挟まれた状態において、少なくとも導管３０のｚ方向の内径と同等の幅であることが望ましい。このように構成すれば、超音波はｚ方向について導管３０内の大部分を透過するので、気泡の検出漏れを少なくできる。
　また、粘性の大きい液体中の気泡は、導管３０の中央部を通りやすくなる。よって、粘性の大きい液体中の気泡を検出する場合は、導管３０の中央部を超音波が透過するように、幅ｈ１及び幅ｈ２は、少なくとも導管３０の内径の半分程度の大きさとすればよい。ただし、実用的には、安全性を再優先し、幅ｈ１及び幅ｈ２は、導管３０のｚ方向の内径と同等の幅とすることが好ましい。 As shown in FIGS. 1B to 1D, as an example, in the z direction perpendicular to the liquid flow direction (y direction) and the ultrasonic wave transmission direction (x direction), the width h1 and second of the first vibrating surface 111 The width h2 of the vibration surface 211 is configured to have the same size.
In the case of detecting bubbles in the liquid having a small viscosity with respect to the width h1 and the width h2, at least in a state where the flexible conduit 30 is sandwiched between the first vibration surface 111 and the second vibration surface 211, It is desirable that the width be equal to the inner diameter of the conduit 30 in the z direction. If comprised in this way, since the ultrasonic wave permeate | transmits most inside the conduit | pipe 30 about az direction, the detection leak of a bubble can be decreased.
In addition, bubbles in the highly viscous liquid easily pass through the central portion of the conduit 30. Therefore, when detecting bubbles in a highly viscous liquid, the width h1 and the width h2 may be at least about half the inner diameter of the conduit 30 so that the ultrasonic wave is transmitted through the central portion of the conduit 30. . However, practically, safety is given priority again, and the width h1 and the width h2 are preferably set to be equal to the inner diameter of the conduit 30 in the z direction.
　超音波振動子１２０及び２２０としては、円板状の圧電素子が用いられ、その両面にそれぞれ不図示の電極が取り付けられており、入力された電気信号を機械的振動に変換し、また、伝達された機械的振動を電気信号に変換して出力することができる。超音波振動子１２０及び２２０は、超音波伝達体１１０及び２１０の内部にそれぞれ埋め込まれて配置される。圧電素子の材料としては、チタン酸ジルコン酸鉛等の圧電セラミックス、酸化亜鉛等の圧電薄膜、フッ化ビニリデン等の圧電高分子膜等が適用可能である。本実施形態では、圧電素子の材料としてチタン酸ジルコン酸鉛を用い、電極として銀と白金を用いた。 As the ultrasonic transducers 120 and 220, disk-shaped piezoelectric elements are used, and electrodes (not shown) are attached to both surfaces of the transducers to convert input electric signals into mechanical vibrations and transmit them. The generated mechanical vibration can be converted into an electrical signal and output. The ultrasonic transducers 120 and 220 are embedded and disposed inside the ultrasonic transmission bodies 110 and 210, respectively. As a material of the piezoelectric element, piezoelectric ceramics such as lead zirconate titanate, piezoelectric thin films such as zinc oxide, piezoelectric polymer films such as vinylidene fluoride, and the like are applicable. In this embodiment, lead zirconate titanate is used as the material of the piezoelectric element, and silver and platinum are used as the electrodes.
　導管３０は、軟質塩化ビニル（ＰＶＣ）、シリコン（Ｓｉ）等の可撓性のチューブで形成され、例えば、医療用のチューブとしては、外径が５．５～６．５ｍｍ、内径が３．５～４．５ｍｍのもの等が用いられる。 The conduit 30 is formed of a flexible tube such as soft vinyl chloride (PVC) or silicon (Si). For example, as a medical tube, the outer diameter is 5.5 to 6.5 mm and the inner diameter is 3. The one having 5 to 4.5 mm is used.
　以上、説明した一対の超音波センサヘッド１を構成する第１のセンサヘッド１０及び第２のセンサヘッド２０は、超音波検出器の送信ヘッド及び受信ヘッドとしてそれぞれ用いることができる。
　次に、第１のセンサヘッドを送信ヘッドとして用い、第２のセンサヘッドを受信ヘッドとして用いる構成を第１実施形態において説明し、第２のセンサヘッドを送信ヘッドとして用い、第１のセンサヘッドを受信ヘッドとして用いる構成を第２実施形態において説明する。 As described above, the first sensor head 10 and the second sensor head 20 constituting the pair of ultrasonic sensor heads 1 described above can be used as a transmission head and a reception head of an ultrasonic detector, respectively.
Next, a configuration in which the first sensor head is used as a transmission head and the second sensor head is used as a reception head will be described in the first embodiment, and the second sensor head is used as a transmission head. In the second embodiment, a configuration in which is used as a receiving head will be described.
＜第１実施形態＞
　図２を参照して、本発明の第１実施形態について説明する。図１と同様の構成については同じ符号を付して説明を省略する。
　図２Ａは、導管を挟んで対向配置される一対の超音波センサヘッド１Ａを示し、図２Ｂは、図２ＡのＹ－Ｙ断面図である。 <First Embodiment>
A first embodiment of the present invention will be described with reference to FIG. The same components as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.
FIG. 2A shows a pair of ultrasonic sensor heads 1A arranged to face each other with a conduit interposed therebetween, and FIG. 2B is a YY sectional view of FIG. 2A.
　一対の超音波センサヘッド１Ａは、送信ヘッドとしての第１のセンサヘッド１０Ａと、受信ヘッドとしての第２のセンサヘッド２０Ａと、を含んで構成され、導管３０としてのチューブ（外径５．５ｍｍ、内径３．５ｍｍ）を挟んで対向して配置される。 The pair of ultrasonic sensor heads 1A includes a first sensor head 10A as a transmission head and a second sensor head 20A as a reception head, and is a tube (outer diameter 5.5 mm) as a conduit 30. And an inner diameter of 3.5 mm).
　第１のセンサヘッド１０Ａは、送信面となる第１の振動面１１１Ａが形成された超音波伝達体１１０Ａと、電気信号と振動とを変換する超音波振動子１２０と、を備える。
　第２のセンサヘッド２０Ａは、受信面となる第２の振動面２１１Ａが形成された超音波伝達体２１０Ａと、電気信号と振動とを変換する超音波振動子２２０と、を備える。
　超音波伝達体１１０Ａ及び２１０Ａは、それぞれの振動面の形状が異なる以外は、超音波伝達体１１０及び２１０と同様に構成される。 The first sensor head 10A includes an ultrasonic transmission body 110A on which a first vibration surface 111A serving as a transmission surface is formed, and an ultrasonic transducer 120 that converts an electric signal and vibration.
The second sensor head 20A includes an ultrasonic transmission body 210A on which a second vibration surface 211A serving as a reception surface is formed, and an ultrasonic transducer 220 that converts an electric signal and vibration.
The ultrasonic transmission bodies 110A and 210A are configured in the same manner as the ultrasonic transmission bodies 110 and 210 except that the shapes of the respective vibration surfaces are different.
　第１の振動面１１１Ａは、図２Ｂに示すように超音波伝達体１１０Ａに凹曲面状に形成され、ｘ方向から見た投影面は、直径６．９ｍｍ（＝ｈ１Ａ＝ｗ１Ａ）の円形である。より詳しく述べると、第１の振動面１１１Ａは、液体の流れ方向（ｙ方向）に垂直な面で切った断面形状が導管３０の側面に沿うように凹曲線状に形成される。このように構成することで、導管３０の側面と第１の振動面１１１Ａとの密着性が向上するので、導管３０内の液体に効率良く超音波を伝達することができる。
　また、導管３０の側面と第１の振動面１１１Ａとの接触面積を大きくできるので、導管３０内の液体に効率良く超音波を伝達することができるとともに超音波の指向性が向上する。さらに、凹曲面状に形成された第１の振動面１１１Ａにおけるレンズ効果により超音波が集束しやすくなる。よって、超音波の送信強度を向上させることができる。 As shown in FIG. 2B, the first vibration surface 111A is formed in a concave curved surface on the ultrasonic transmission body 110A, and the projection surface viewed from the x direction is a circle having a diameter of 6.9 mm (= h1A = w1A). . More specifically, the first vibration surface 111 </ b> A is formed in a concave curve shape such that a cross-sectional shape cut by a surface perpendicular to the liquid flow direction (y direction) is along the side surface of the conduit 30. With this configuration, the adhesion between the side surface of the conduit 30 and the first vibrating surface 111A is improved, so that ultrasonic waves can be efficiently transmitted to the liquid in the conduit 30.
In addition, since the contact area between the side surface of the conduit 30 and the first vibrating surface 111A can be increased, the ultrasonic wave can be efficiently transmitted to the liquid in the conduit 30 and the directivity of the ultrasonic wave is improved. Furthermore, the ultrasonic wave is easily focused by the lens effect on the first vibration surface 111A formed in a concave curved surface. Therefore, the transmission intensity of ultrasonic waves can be improved.
　第２の振動面２１１Ａは、図２Ａ及び図２Ｂに示すように、超音波伝達体２１０Ａに凸曲面状に形成され、－ｘ方向から見た投影面は、幅ｗ２Ａ＝１．４ｍｍ、幅ｈ２Ａ＝６．９ｍｍの矩形状である。より詳しく述べると、第２の振動面２１１Ａは、図２Ａに示すように、超音波の送受信方向（ｘ方向）及び液体の流れ方向（ｙ方向）に平行な面（ｘｙ平面）で切った断面形状が可撓性を備える導管３０の側面に対して凸曲線状に形成される。このように構成することで、導管３０の側面と第２の振動面２１１Ａとの密着性が向上するので、液体を透過した超音波を効率良く伝達することができる。よって、受信強度を向上させることができる。 As shown in FIGS. 2A and 2B, the second vibration surface 211A is formed in a convex curve shape on the ultrasonic transmission body 210A, and the projection surface viewed from the −x direction has a width w2A = 1.4 mm and a width h2A. = A rectangular shape of 6.9 mm. More specifically, as shown in FIG. 2A, the second vibrating surface 211A is a cross section cut by a plane (xy plane) parallel to the ultrasonic transmission / reception direction (x direction) and the liquid flow direction (y direction). The shape is formed in a convex curve shape with respect to the side surface of the conduit 30 having flexibility. By comprising in this way, since the adhesiveness of the side surface of the conduit | pipe 30 and the 2nd vibration surface 211A improves, the ultrasonic wave which permeate | transmitted the liquid can be transmitted efficiently. Therefore, the reception strength can be improved.
　また、液体の流れ方向（ｙ方向）について、第２の振動面２１１Ａ（受信面）の幅ｗ２Ａが小さいので、受信面における微小気泡の投影面に占める割合が増加する。よって、液体を透過する超音波が微小気泡で反射して受信面に到達する超音波が減衰する割合が大きくなり、微小気泡を高感度で検出できる。 Also, since the width w2A of the second vibrating surface 211A (receiving surface) is small in the liquid flow direction (y direction), the proportion of the microbubbles in the projection surface on the receiving surface increases. Therefore, the rate at which the ultrasonic waves that pass through the liquid are reflected by the microbubbles and the ultrasonic waves that reach the receiving surface are attenuated increases, and the microbubbles can be detected with high sensitivity.
　第１実施形態に係る一対の超音波センサヘッド１Ａによれば、以下のような効果が奏される。 The pair of ultrasonic sensor heads 1A according to the first embodiment has the following effects.
　（１）液体の流れ方向（ｙ方向）について、第２の振動面２１１Ａ（受信面）の幅ｗ２Ａは、第１の振動面１１１Ａ（送信面）の幅ｗ１Ａよりも小さい。このように構成することで、第１のセンサヘッド１０Ａ（送信ヘッド）及び第２のセンサヘッド２０Ａ（受信ヘッド）を対向して配置する際に、液体の流れ方向（ｙ方向）について、送信面が広いので、送信面と受信面との精密な位置合わせを行わなくても、送信波が受信面を外れないように送受信が可能となる。よって、超音波の送受信の強度を強くすることができ、超音波検出器に一対の超音波センサヘッド１Ａを適用したときに受信ヘッドからの受信電圧が安定する。 (1) In the liquid flow direction (y direction), the width w2A of the second vibrating surface 211A (receiving surface) is smaller than the width w1A of the first vibrating surface 111A (transmitting surface). With such a configuration, when the first sensor head 10A (transmission head) and the second sensor head 20A (reception head) are arranged to face each other, the transmission surface in the liquid flow direction (y direction) Therefore, transmission / reception can be performed so that the transmission wave does not deviate from the reception surface without precise alignment between the transmission surface and the reception surface. Therefore, the intensity of ultrasonic transmission / reception can be increased, and the reception voltage from the reception head is stabilized when the pair of ultrasonic sensor heads 1A is applied to the ultrasonic detector.
　（２）液体の流れ方向（ｙ方向）について第２の振動面２１１Ａ（受信面）の幅ｗ２Ａが小さいので、受信面における微小気泡の投影面に占める割合が大きい。よって、液体を透過する超音波が微小気泡で反射して受信面に到達する超音波が減衰する割合が大きいので、微小気泡を高感度で検出できる。 (2) Since the width w2A of the second vibration surface 211A (reception surface) is small in the liquid flow direction (y direction), the proportion of the microbubbles in the projection surface on the reception surface is large. Therefore, since the ultrasonic wave which permeate | transmits a liquid reflects with a microbubble and the ratio which the ultrasonic wave which reaches | attains a receiving surface attenuate | damps is large, a microbubble can be detected with high sensitivity.
　（３）第１の振動面１１１Ａ（送信面）は、液体の流れ方向（ｙ方向）に垂直な面で切った断面形状が導管３０の側面に沿うように凹曲線状に形成される。このように構成することで、導管３０の側面と送信面との密着性が向上し、さらに両者の接触面積を大きくできるので、導管３０内の液体に効率良く超音波を伝達することができる。また、送信面が大きいため超音波の指向性が向上する。また、送信面が凹曲面状に形成されるので、そのレンズ効果により超音波が集束し、さらに指向性が向上する。よって、超音波の送信強度を上げることができ、超音波検出器における出力電圧が安定する。 (3) The first vibration surface 111A (transmission surface) is formed in a concave curve shape so that a cross-sectional shape cut by a surface perpendicular to the liquid flow direction (y direction) is along the side surface of the conduit 30. By comprising in this way, the adhesiveness of the side surface of the conduit | pipe 30 and a transmission surface improves, and also both contact areas can be enlarged, Therefore An ultrasonic wave can be efficiently transmitted to the liquid in the conduit | pipe 30. FIG. Moreover, since the transmission surface is large, the directivity of ultrasonic waves is improved. Further, since the transmission surface is formed in a concave curved surface, the ultrasonic wave is focused by the lens effect, and the directivity is further improved. Therefore, the transmission intensity of the ultrasonic wave can be increased, and the output voltage in the ultrasonic detector is stabilized.
　（４）導管３０が可撓性を備えており、第２の振動面２１１Ａ（受信面）は、超音波の送受信方向（ｘ方向）及び液体の流れ方向（ｙ方向）に平行な面（ｘｙ平面）で切った断面形状が凸曲線状に形成される。このように構成することで、導管３０の側面と受信面との密着性が向上するので、液体を透過した超音波を効率良く伝達することができる。よって、受信強度を上げることができ、超音波検出器における出力電圧が安定する。
　また、液体の流れ方向（ｙ方向）についての受信面の幅ｗ２Ａが小さいので、受信面における微小気泡の投影面に占める割合が増加する。よって、液体を透過する超音波が微小気泡で反射して受信面に到達する超音波が減衰する割合が大きくなり、微小気泡を高感度で検出できる。 (4) The conduit 30 is flexible, and the second vibrating surface 211A (receiving surface) is a surface (xy) parallel to the ultrasonic transmission / reception direction (x direction) and the liquid flow direction (y direction). A cross-sectional shape cut by a plane is formed in a convex curve shape. By comprising in this way, the adhesiveness of the side surface of the conduit | pipe 30 and a receiving surface improves, Therefore The ultrasonic wave which permeate | transmitted the liquid can be transmitted efficiently. Therefore, the reception intensity can be increased and the output voltage at the ultrasonic detector is stabilized.
In addition, since the width w2A of the receiving surface in the liquid flow direction (y direction) is small, the proportion of the microbubbles on the projection surface on the receiving surface increases. Therefore, the rate at which the ultrasonic waves that pass through the liquid are reflected by the microbubbles and the ultrasonic waves that reach the receiving surface are attenuated increases, and the microbubbles can be detected with high sensitivity.
＜第２実施形態＞
　図３及び図４を参照して、本発明の第２実施形態について説明する。図１及び図２と同様の構成については同じ符号を付して説明を省略する。
　図３Ａは、導管を挟んで対向配置される一対の超音波センサヘッド１Ｂを示し、図３Ｂは、図３ＡのＹ－Ｙ断面図である。 Second Embodiment
A second embodiment of the present invention will be described with reference to FIGS. The same components as those in FIGS. 1 and 2 are denoted by the same reference numerals and description thereof is omitted.
FIG. 3A shows a pair of ultrasonic sensor heads 1B arranged to face each other with a conduit interposed therebetween, and FIG. 3B is a YY sectional view of FIG. 3A.
　一対の超音波センサヘッド１Ｂは、送信ヘッドとしての第２のセンサヘッド２０Ｂ（２０Ａ）と、受信ヘッドとしての第１のセンサヘッド１０Ｂ（１０Ａ）と、を含んで構成され、導管３０としてのチューブ（外径５．５ｍｍ、内径３．５ｍｍ）を挟んで対向して配置される。 The pair of ultrasonic sensor heads 1B includes a second sensor head 20B (20A) as a transmission head and a first sensor head 10B (10A) as a reception head, and a tube as a conduit 30 They are arranged facing each other with an outer diameter of 5.5 mm and an inner diameter of 3.5 mm.
　第２実施形態においては、第１実施形態で送信ヘッドとして用いた第１のセンサヘッド１０Ａを受信ヘッド（第１のセンサヘッド１０Ｂ）として用い、第１実施形態で受信ヘッドとして用いた第２のセンサヘッド２０Ａを送信ヘッド（第２のセンサヘッド２０Ｂ）として用いた点で、第１の実施形態と異なる。各振動面の形状等は、第１の実施形態と同様であるので説明を省略する。 In the second embodiment, the first sensor head 10A used as the transmission head in the first embodiment is used as the reception head (first sensor head 10B), and the second sensor head 10A used as the reception head in the first embodiment is used. The difference from the first embodiment is that the sensor head 20A is used as a transmission head (second sensor head 20B). Since the shape of each vibration surface is the same as that of the first embodiment, description thereof is omitted.
　第２の振動面２１１Ｂ（２１１Ａ）は、図３Ａ及び図３Ｂに示すように、超音波伝達体２１０Ｂ（２１０Ａ）に凸曲面状に形成される。より詳しく述べると、第２の振動面２１１Ｂ（２１１Ａ）は、図３Ａに示すように、超音波の送受信方向（ｘ方向）及び液体の流れ方向（ｙ方向）に平行な面（ｘｙ平面）で切った断面形状が可撓性を備える導管３０の側面に対して凸曲線状に形成される。このように構成することで、導管３０の側面と第２の振動面２１１Ｂ（２１１Ａ）との密着性が向上するので、導管３０内の液体に効率良く超音波を伝達することができる。よって、送信強度を上げることができる。 As shown in FIGS. 3A and 3B, the second vibration surface 211B (211A) is formed in a convex curve shape on the ultrasonic transmission body 210B (210A). More specifically, as shown in FIG. 3A, the second vibration surface 211B (211A) is a surface (xy plane) parallel to the ultrasonic wave transmission / reception direction (x direction) and the liquid flow direction (y direction). The cut cross-sectional shape is formed in a convex curve shape with respect to the side surface of the conduit 30 having flexibility. By comprising in this way, since the adhesiveness of the side surface of the conduit | pipe 30 and the 2nd vibration surface 211B (211A) improves, an ultrasonic wave can be efficiently transmitted to the liquid in the conduit | pipe 30. FIG. Therefore, the transmission intensity can be increased.
　第１の振動面１１１Ｂ（１１１Ａ）は、図３Ｂに示すように超音波伝達体１１０Ｂに凹曲面状に形成される。より詳しく述べると、第１の振動面１１１Ｂ（１１１Ａ）は、液体の流れ方向（ｙ方向）に垂直な面で切った断面形状が導管３０の側面に沿うように凹曲線状に形成される。このように構成することで、導管３０の側面と第１の振動面１１１Ｂ（１１１Ａ）との密着性が向上するので、導管３０内の液体を透過した超音波を効率良く伝達することができる。よって、受信強度を上げることができる。 The first vibration surface 111B (111A) is formed in a concave curved surface on the ultrasonic transmission body 110B as shown in FIG. 3B. More specifically, the first vibration surface 111 </ b> B (111 </ b> A) is formed in a concave curve shape so that a cross-sectional shape cut by a surface perpendicular to the liquid flow direction (y direction) is along the side surface of the conduit 30. With this configuration, the adhesion between the side surface of the conduit 30 and the first vibrating surface 111B (111A) is improved, so that the ultrasonic wave that has passed through the liquid in the conduit 30 can be efficiently transmitted. Therefore, the reception intensity can be increased.
　第２実施形態において、微小気泡を高感度に検出する仕組みについて、図４を参照して説明する。図４Ａは、第２の振動面２１１Ｂ（送信面）からの送信波の指向性が高い場合の微小気泡の投影面を説明する図であり、図４Ｂは、第２の振動面２１１Ｂ（送信面）からの送信波の指向性が低い場合の微小気泡の投影面を説明する図である。 In the second embodiment, a mechanism for detecting microbubbles with high sensitivity will be described with reference to FIG. FIG. 4A is a diagram illustrating a projection surface of microbubbles when the directivity of a transmission wave from the second vibration surface 211B (transmission surface) is high, and FIG. 4B illustrates the second vibration surface 211B (transmission surface). FIG. 9 is a diagram for explaining a projection surface of microbubbles when the directivity of a transmission wave from) is low.
　図４Ａに示すように、送信面から送信される超音波が指向性の高いものである場合、受信面の一部分（斜線部分ＰＡ）において、送信波を受信する。このような場合、受信面全体における微小気泡の投影面は、割合が極僅かであると考えられるが、受信面において送信波を受ける斜線部分ＰＡに関しては、微小気泡の投影面が占める割合は、検出可能な程度に大きいと言える。よって、液体を透過する超音波が微小気泡で反射すると、受信面のうち送信波を受ける斜線部分ＰＡに到達する超音波が減衰する割合が大きくなるので、微小気泡を高感度で検出できる。 As shown in FIG. 4A, when the ultrasonic wave transmitted from the transmission side is of high directivity, in a portion of the receiving surface (hatched portion P A), to receive transmission waves. In this case, the projection surface of the microbubbles in the entire receiving surface, the proportion is considered to be negligible, with respect to the hatched portions P A which receives the transmission wave at the receiving side, the ratio of the projection surface of the microbubbles occupied It can be said to be large enough to be detected. Therefore, the ultrasonic waves transmitted through the liquid is reflected by microbubbles, the ultrasonic wave reaches the hatched portion P A which receives the transmission wave of the reception surface is the ratio of attenuation is large, it can detect microbubbles with high sensitivity.
　送信面から送信される超音波が指向性の低いものである場合、例えば、送信面の幅ｗ２Ｂが小さいことに起因して送信波の指向性が低下する場合や、送信面が凸曲面状に形成されるので、そのレンズ効果により超音波が拡散しやすくなる場合が考えられる。
　図４Ｂに示すように、送信面から送信される超音波が指向性の低いものである場合、受信面の大部分（斜線部分ＰＢ）において、送信波を受信する。受信面は、送信面よりも液体の流れ方向（ｙ方向）についての幅が広いため、液体を透過した超音波は、ｙ方向に沿って拡散しても受信面うち斜線部分ＰＢにおいて受信が可能である。また、微小気泡が存在する場合、受信面において微小気泡は超音波の拡散に伴ってｙ方向に拡大して投影される。よって、液体を透過する超音波が微小気泡で反射すると、受信面のうち送信波を受ける斜線部分ＰＢに到達するｙ方向に拡散した超音波が減衰する割合が大きくなるので、微小気泡を高感度で検出できる。 If the ultrasonic wave transmitted from the transmitting side is low in directivity, for example, when the directivity of the transmission wave due to a small width w2 B transmission side is lowered, the transmission surface convex curved Therefore, it may be possible that the ultrasonic wave is easily diffused by the lens effect.
As shown in FIG. 4B, when the ultrasonic wave transmitted from the transmission surface has low directivity, the transmission wave is received in most of the reception surface (shaded portion P B ). Since the receiving surface is wider in the liquid flow direction (y direction) than the transmitting surface, even if the ultrasonic wave that has passed through the liquid diffuses along the y direction, it is received at the hatched portion P B of the receiving surface. Is possible. When microbubbles exist, the microbubbles are enlarged and projected in the y direction along with the diffusion of ultrasonic waves on the receiving surface. Therefore, the ultrasonic waves transmitted through the liquid is reflected by microbubbles, since ultrasonic waves spread in the y-direction to reach the hatched portion P B which receives the transmission wave of the reception surface proportion to attenuation increases, high microbubbles Can be detected with sensitivity.
　第２実施形態に係る一対の超音波センサヘッド１Ｂによれば、以下のような効果が奏される。 According to the pair of ultrasonic sensor heads 1B according to the second embodiment, the following effects are exhibited.
　（５）液体の流れ方向（ｙ方向）について、第１の振動面１１１Ｂ（受信面）の幅ｗ１Ｂは、第２の振動面２１１Ｂ（送信面）の幅ｗ２Ｂよりも小さい。このように構成することで、第２のセンサヘッド２０Ｂ（送信ヘッド）及び第１のセンサヘッド１０Ｂ（受信ヘッド）を対向して配置する際に、液体の流れ方向（ｙ方向）について、受信面が広いので、送信面と受信面との精密な位置合わせを行わなくても、送信波が受信面を外れないように送受信が可能となる。よって、超音波の送受信の強度を強くすることができ、超音波検出器に一対の超音波センサヘッド１Ｂを適用したときに受信ヘッドからの受信電圧が安定する。 (5) In the liquid flow direction (y direction), the width w1B of the first vibrating surface 111B (receiving surface) is smaller than the width w2B of the second vibrating surface 211B (transmitting surface). With this configuration, when the second sensor head 20B (transmission head) and the first sensor head 10B (reception head) are arranged to face each other, the reception surface in the liquid flow direction (y direction). Therefore, transmission / reception can be performed so that the transmission wave does not deviate from the reception surface without precise alignment between the transmission surface and the reception surface. Therefore, the intensity of ultrasonic transmission / reception can be increased, and the reception voltage from the reception head is stabilized when the pair of ultrasonic sensor heads 1B is applied to the ultrasonic detector.
　（６）第１の振動面１１１Ｂ（受信面）は、液体の流れ方向（ｙ方向）に垂直な面で切った断面形状が導管３０の側面に沿うように凹曲線状に形成される。このように構成することで、導管３０の側面と送信面との密着性が向上するため、導管３０内の液体を透過した超音波を効率良く伝達することができる。よって、超音波の受信強度を上げることができ、超音波検出器における出力電圧が安定する。 (6) The first vibrating surface 111B (receiving surface) is formed in a concave curve shape so that a cross-sectional shape cut by a surface perpendicular to the liquid flow direction (y direction) is along the side surface of the conduit 30. By comprising in this way, since the adhesiveness of the side surface of the conduit | pipe 30 and a transmission surface improves, the ultrasonic wave which permeate | transmitted the liquid in the conduit | pipe 30 can be transmitted efficiently. Therefore, the reception intensity of the ultrasonic wave can be increased, and the output voltage in the ultrasonic detector is stabilized.
　（７）導管３０が可撓性を備えており、第２の振動面２１１Ｂ（送信面）は、超音波の送受信方向（ｘ方向）及び液体の流れ方向（ｙ方向）に平行な面（ｘｙ平面）で切った断面形状が凸曲線状に形成される。このように構成することで、導管３０の側面と受信面との密着性が向上するので、導管３０内の液体に効率良く超音波を伝達することができる。よって、送信強度を上げることができ、気泡検出器における出力電圧が安定する。 (7) The conduit 30 has flexibility, and the second vibration surface 211B (transmission surface) is a surface (xy) parallel to the ultrasonic transmission / reception direction (x direction) and the liquid flow direction (y direction). A cross-sectional shape cut by a plane is formed in a convex curve shape. By comprising in this way, since the adhesiveness of the side surface of the conduit | pipe 30 and a receiving surface improves, an ultrasonic wave can be efficiently transmitted to the liquid in the conduit | pipe 30. FIG. Therefore, the transmission intensity can be increased and the output voltage at the bubble detector is stabilized.
　（８）液体の流れ方向（ｙ方向）について、第１の振動面１１１Ｂ（受信面）の幅ｗ１Ｂは、第２の振動面２１１（送信面）の幅ｗ２Ｂよりも小さい。このように構成することで、送信面からの送信される超音波の指向性が高い場合には、液体を透過する超音波が微小気泡で反射すると、受信面のうち送信波を受ける一部分（斜線部分ＰＡ）に到達する超音波が減衰する割合が大きくなるので、微小気泡を高感度で検出できる。
　また、超音波の指向性が低い場合には、液体を透過する超音波が微小気泡で反射すると、受信面のうち送信波を受ける大部分（斜線部分ＰＢ）に到達するｙ方向に拡散した超音波が減衰する割合が大きくなるので、微小気泡を高感度で検出できる。 (8) In the liquid flow direction (y direction), the width w1B of the first vibration surface 111B (reception surface) is smaller than the width w2B of the second vibration surface 211 (transmission surface). With this configuration, when the directivity of the ultrasonic wave transmitted from the transmission surface is high, when the ultrasonic wave that passes through the liquid is reflected by the microbubbles, a part of the reception surface that receives the transmission wave (oblique line) Since the rate of attenuation of the ultrasonic waves that reach the portion P A ) increases, microbubbles can be detected with high sensitivity.
In addition, when the directivity of the ultrasonic wave is low, when the ultrasonic wave passing through the liquid is reflected by the microbubbles, the ultrasonic wave diffuses in the y direction reaching the most part (the hatched part P B ) that receives the transmission wave on the receiving surface. Since the rate at which ultrasonic waves are attenuated increases, microbubbles can be detected with high sensitivity.
　以下、実施例により本発明をさらに詳細に説明する。しかしながら本発明の範囲はかかる実施例に制限されるものではない。
　上述の第１実施形態及び第２実施形態で説明した一対の超音波センサヘッド、及び従来技術の構成に対応する超音波センサヘッドを用いて、気泡検出実験を行った。気泡検出実験は、不図示の血液透析装置を用いて行った。 Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples.
A bubble detection experiment was performed using the pair of ultrasonic sensor heads described in the first and second embodiments and the ultrasonic sensor head corresponding to the configuration of the conventional technology. The bubble detection experiment was performed using a hemodialysis machine (not shown).
［実施例１］
　血液透析装置は、導管３０として可撓性を有するチューブと、第１実施形態で説明した超音波センサヘッド１Ａを有する超音波検出器と、を含んで構成される。チューブは、外径が５．５ｍｍ、内径が３．５ｍｍの可撓性を有する塩化ビニル製のものを用意した。血液や薬液の代わりとして、チューブ内に体液と同程度の温度に加温された約３６℃の水を２５０ｍＬ／分の流速で流した。
　チューブを挟持するように一対の超音波センサヘッド１Ａを対向配置して取り付けた。チューブ内に水を流した状態でマイクロシリンジを用いて０．３μＬの微小気泡（気泡の直径約０．８３ｍｍ）を単発注入し、血液透析装置にて、気泡の検知率と電圧の変化を確認する気泡検出実験を行った。これを３０回繰り返して、気泡検知率及び電圧の安定性を評価した。 [Example 1]
The hemodialysis apparatus includes a tube having flexibility as the conduit 30 and an ultrasonic detector having the ultrasonic sensor head 1A described in the first embodiment. As the tube, a flexible vinyl chloride tube having an outer diameter of 5.5 mm and an inner diameter of 3.5 mm was prepared. As an alternative to blood or drug solution, approximately 36 ° C. water heated to a temperature similar to that of body fluid was allowed to flow through the tube at a flow rate of 250 mL / min.
A pair of ultrasonic sensor heads 1 </ b> A were arranged facing each other so as to sandwich the tube. A micro-syringe is used to inject 0.3 μL microbubbles (bubble diameter is approximately 0.83 mm) with water flowing in the tube, and the change in the bubble detection rate and voltage is confirmed with a hemodialyzer. An air bubble detection experiment was conducted. This was repeated 30 times to evaluate the bubble detection rate and the voltage stability.
［実施例２］
　超音波センサヘッドとして、第２実施形態で説明した一対の超音波センサヘッド１Ｂを用いて、実施例１と同様に気泡検出実験を行った。 [Example 2]
Using the pair of ultrasonic sensor heads 1B described in the second embodiment as the ultrasonic sensor head, a bubble detection experiment was performed in the same manner as in Example 1.
［比較例１］
　超音波センサヘッドとして、第１実施形態で説明した第１のセンサヘッド１０Ａの２つで構成される一対の超音波センサヘッドを用いて、実施例１と同様に気泡検出実験を行った。 [Comparative Example 1]
As an ultrasonic sensor head, a bubble detection experiment was performed in the same manner as in Example 1 using a pair of ultrasonic sensor heads including the first sensor head 10A described in the first embodiment.
［比較例２］
　超音波センサヘッドとして、第１実施形態で説明した第２のセンサヘッド２０Ａの２つで構成される一対の超音波センサヘッドを用いて、実施例１と同様に気泡検出実験を行った。
　実施例１、２、及び比較例１、２の実験結果を表１に示す。 [Comparative Example 2]
As an ultrasonic sensor head, a bubble detection experiment was performed in the same manner as in Example 1 by using a pair of ultrasonic sensor heads including the second sensor head 20A described in the first embodiment.
The experimental results of Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、比較例１に比べて実施例１及び２は、気泡検知率が大幅に向上した。なお、本実施例における気泡検出実験は、粘性の小さい水を用いて行ったため、気泡検知率が９３％及び８７％となったが、水に比べて粘性の大きい輸液に用いる液体や血液においては、微小気泡はチューブの中央部を通過しやすいため、検知率は１００％になると推測される。
　また比較例２に比べて、実施例１及び２は、受信電圧変化が±０．１Ｖで安定した結果となったので、本発明の一対の超音波センサヘッドを備える超音波検出器は、誤検知の発生を抑制できる。よって、誤検知を発生させないために必要なハードウェアにおける複雑な回路設計や、ソフトウェアにおけるアルゴリズムの工夫等を行わなくてもよく、超音波検出器の構成を簡易化できる。 As shown in Table 1, the bubble detection rate in Examples 1 and 2 was significantly improved as compared with Comparative Example 1. In addition, since the bubble detection experiment in this example was performed using water with low viscosity, the bubble detection rate was 93% and 87%. However, in the liquid and blood used for infusion with higher viscosity than water, Since the microbubbles easily pass through the central part of the tube, the detection rate is estimated to be 100%.
In addition, compared with Comparative Example 2, Examples 1 and 2 showed that the received voltage change was stabilized at ± 0.1 V. Therefore, the ultrasonic detector equipped with the pair of ultrasonic sensor heads of the present invention is erroneous. Generation of detection can be suppressed. Therefore, it is not necessary to perform complicated circuit design in hardware necessary for preventing erroneous detection, or to devise an algorithm in software, and the configuration of the ultrasonic detector can be simplified.
　以上、本発明の一対の超音波センサヘッド１及び超音波検出器の好ましい一実施形態について説明したが、本発明は、上述した実施形態に制限されるものではなく、適宜変更が可能である。
　例えば、実施形態における第１の振動面１１１について、一例として円形状のものを示したが、楕円状や矩形状としてもよい。 The preferred embodiment of the pair of ultrasonic sensor heads 1 and the ultrasonic detector according to the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and can be modified as appropriate.
For example, the first vibrating surface 111 according to the embodiment has a circular shape as an example, but may be an elliptical shape or a rectangular shape.
　また、第１実施形態及び第２実施形態では、第１の振動面を、超音波伝達体に凹曲面状に形成したが、これに限らない。即ち、図５Ａ及び図５Ｂに示すように、第１の振動面１１１Ｃを、超音波伝達体１１０Ｃに凸曲面状に形成してもよい。
　また、第１実施形態では、第２の振動面を、超音波伝達体に凸曲面状に形成したが、これに限らない。即ち、図５Ａ及び図５Ｂに示すように、第２の振動面２１１Ｃを、超音波伝達体２１０Ｃに平面状（直線状）に形成してもよい。 Moreover, in 1st Embodiment and 2nd Embodiment, although the 1st vibration surface was formed in the concave curved surface shape in the ultrasonic transmission body, it is not restricted to this. That is, as shown in FIGS. 5A and 5B, the first vibration surface 111C may be formed in a convex curved surface on the ultrasonic transmission body 110C.
In the first embodiment, the second vibration surface is formed in a convex curved surface on the ultrasonic transmission body, but the present invention is not limited to this. That is, as shown in FIGS. 5A and 5B, the second vibration surface 211C may be formed in a planar shape (linear shape) on the ultrasonic transmission body 210C.
　また、第１及び第２実施形態では、超音波センサヘッドが振動面で導管と接触して超音波と伝達する接触式による構成を示したが、非接触式の超音波センサヘッドにも本発明の概念は適用可能である。 In the first and second embodiments, the contact-type configuration in which the ultrasonic sensor head is in contact with the conduit on the vibration surface and transmits ultrasonic waves is shown, but the present invention is also applied to a non-contact type ultrasonic sensor head. The concept of is applicable.
　また、第１及び第２実施形態では、導管として可撓性を備えるチューブを一例として示したがこれに限らない。導管としては、医療用や工業用の樹脂製のチューブに限らず金属チューブ、配管等にも本発明の概念は適用可能である。 In the first and second embodiments, a flexible tube is shown as an example of the conduit. However, the present invention is not limited to this. As the conduit, the concept of the present invention is applicable not only to medical and industrial resin tubes but also to metal tubes, pipes and the like.
　また、本発明の超音波センサヘッドを備える超音波検出器を適用可能な一例として、血液透析装置を示したが、これに限らない。気泡の存在が問題となる血液回路や輸液回路に接続される医療機器等に適用可能であり、また、医療分野以外においても、気泡を検出する必要がある分野に広く適用可能である。 In addition, as an example to which an ultrasonic detector including the ultrasonic sensor head of the present invention can be applied, a hemodialysis apparatus has been shown, but the present invention is not limited thereto. The present invention can be applied to a blood vessel or a medical device connected to an infusion circuit in which the presence of air bubbles is a problem, and can be widely applied to fields where air bubbles need to be detected outside the medical field.
　１　一対の超音波センサヘッド
　１０　第１のセンサヘッド
　２０　第２のセンサヘッド
　３０　導管（チューブ）
　１１０、２１０　超音波伝達体
　１１１　第１の振動面
　１２０、２２０　超音波振動子
　２１１　第２の振動面 1 pair of ultrasonic sensor heads 10 first sensor head 20 second sensor head 30 conduit (tube)
110, 210 Ultrasonic transmission body 111 First vibration surface 120, 220 Ultrasonic vibrator 211 Second vibration surface

Claims (5)

  1. 　液体が流れる導管を挟んで対向配置され、超音波を送受信可能な一対の超音波センサヘッドであって、
    　前記一対の超音波センサヘッドの一方は、前記導管に面する第１の振動面を備え、
    　前記一対の超音波センサヘッドの他方は、前記導管に面する第２の振動面を備え、
    　前記液体の流れ方向について、前記第２の振動面の幅は、前記第１の振動面の幅よりも小さく、
    　前記第１の振動面及び前記第２の振動面のいずれか一方が超音波の送信面として用いられ、他方が超音波の受信面として用いられる一対の超音波センサヘッド。     A pair of ultrasonic sensor heads arranged opposite to each other across a conduit through which liquid flows and capable of transmitting and receiving ultrasonic waves,
    One of the pair of ultrasonic sensor heads includes a first vibration surface facing the conduit;
    The other of the pair of ultrasonic sensor heads includes a second vibration surface facing the conduit,
    Regarding the flow direction of the liquid, the width of the second vibration surface is smaller than the width of the first vibration surface,
    A pair of ultrasonic sensor heads, wherein one of the first vibration surface and the second vibration surface is used as an ultrasonic wave transmission surface and the other is used as an ultrasonic wave reception surface.
  2. 　前記第１の振動面が超音波の送信面として用いられ、前記第２の振動面が超音波の受信面として用いられる請求項１に記載の一対の超音波センサヘッド。 The pair of ultrasonic sensor heads according to claim 1, wherein the first vibration surface is used as an ultrasonic wave transmission surface and the second vibration surface is used as an ultrasonic wave reception surface.
  3. 　前記一対の超音波センサヘッドは、前記第１の振動面及び前記第２の振動面において前記導管と接触するように配置され、
    　前記第１の振動面は、前記液体の流れ方向に垂直な面で切った断面形状が凹曲線状又は凸曲線状に形成される請求項１又は２に記載の一対の超音波センサヘッド。     The pair of ultrasonic sensor heads are disposed so as to contact the conduit at the first vibration surface and the second vibration surface,
    3. The pair of ultrasonic sensor heads according to claim 1, wherein the first vibration surface is formed in a concave curve shape or a convex curve shape in a cross-sectional shape cut by a plane perpendicular to the liquid flow direction.
  4. 　前記導管は可撓性を備えており、
    　前記第２の振動面は、前記超音波の送受信方向及び前記液体の流れ方向に平行な面で切った断面形状が凸曲線状又は直線状に形成される請求項３に記載の一対の超音波センサヘッド。     The conduit is flexible;
    4. The pair of ultrasonic waves according to claim 3, wherein the second vibration surface is formed such that a cross-sectional shape cut by a surface parallel to the ultrasonic wave transmission / reception direction and the liquid flow direction is a convex curve shape or a straight line shape. The sensor head.
  5. 　請求項１～４のいずれかに記載の一対の超音波センサヘッドを備え、
    　前記導管を流れる液体中の気泡を検出する超音波検出器。     A pair of ultrasonic sensor heads according to any one of claims 1 to 4,
    An ultrasonic detector for detecting bubbles in the liquid flowing through the conduit.
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