Bubble detector

Abstract

The present invention provides a bubble detector. In making a pair of ultrasonic elements (24, 25) that detect the presence or absence of bubbles in a liquid flowing in a pipe (19) abut against the pipe, the pipe is prevented from being flattened into an oval shape and the flow rate is reduced. The bubble detector of the present invention detects the presence or absence of bubbles in a liquid flowing in a pipe by making a first ultrasonic element (24) provided to a first support member (sensor block (23)) and a second ultrasonic element (25) provided to a second support member (cover (11B)) abut against the pipe (19). A pair of side blocks (35) are provided in a direction intersecting the arrangement direction of the above-described ultrasonic elements (24, 25). In adjusting the interval of the above-described ultrasonic elements (24, 25) according to the thickness of the pipe, the pipe is flattened into a rectangular shape by simultaneously adjusting the interval of the pair of side blocks (35), whereby the pipe is prevented from being flattened into an oval shape and the flow rate is reduced.

Description

Technical Field

[0001] This invention relates to a bubble detector for detecting the presence of bubbles in a liquid flowing in a pipe. Background Technology

[0002] Conventionally, as a bubble detector, there is a known structure comprising: a first ultrasonic element disposed on a first support member, a second ultrasonic element disposed on a second support member and facing the first ultrasonic element across a tube, and a first interval adjustment mechanism that adjusts the interval between the first and second ultrasonic elements according to the diameter of the tube by adjusting the interval between the first and second support members, and a structure that detects the presence of bubbles in a liquid flowing in a tube by receiving ultrasonic waves emitted from either the first or second ultrasonic element by the other ultrasonic element (Patent Document 1).

[0003] Because the propagation efficiency of ultrasound differs in liquids and bubbles, the presence of bubbles in a liquid will interrupt the ultrasound waves, reducing the received intensity. This characteristic can be used to detect bubbles. For accurate bubble detection, the first and second ultrasonic elements need to be tightly fitted to the tube. However, if the spacing between the first and second ultrasonic elements cannot be adjusted when using thin tubes, it will be difficult to ensure proper fit between them, leading to decreased detection accuracy.

[0004] In the bubble detector described above, the distance between the first ultrasonic element and the second ultrasonic element can be adjusted by the first distance adjustment mechanism. Therefore, even when using multiple types of tubes, the first ultrasonic element and the second ultrasonic element can always be in good contact with the tube, thereby preventing a decrease in detection accuracy.

[0005] [Existing Technical Documents]

[0006] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent No. 3447957 Summary of the Invention

[0008] [The problem the invention aims to solve]

[0009] In conventional bubble detectors, the tube is flattened radially using the first and second ultrasonic elements via the aforementioned first interval adjustment mechanism. As a result, the tube is flattened into an elliptical shape, which reduces the flow area inside the tube and may not be able to ensure the required flow rate.

[0010] In view of the above, the present invention provides a bubble detector that enables the first and second ultrasonic elements to fit well against the tube and prevents the tube from being flattened into an elliptical shape, thereby ensuring the required flow rate.

[0011] [Solution to the problem]

[0012] The invention of the first aspect relates to a bubble detector, the bubble detector comprising: a first ultrasonic element disposed on a first support member; a second ultrasonic element disposed on a second support member and facing the first ultrasonic element across a tube; and a first interval adjustment mechanism that adjusts the interval between the first support member and the second support member to adjust the interval between the first ultrasonic element and the second ultrasonic element according to the diameter of the tube.

[0013] Ultrasonic waves emitted from either the first or second ultrasonic element are received by the other ultrasonic element, thereby detecting the presence of air bubbles in a liquid flowing within a pipe. The air bubble detector is characterized in that…

[0014] A pair of side guides facing each other are provided in a direction intersecting the configuration direction of the first and second ultrasonic elements that face each other across the tube, and a second interval adjustment mechanism is provided to adjust the interval between the pair of side guides according to the diameter of the tube.

[0015] [Invention Effects]

[0016] According to the invention of the first embodiment, since the interval between the first ultrasonic element and the second ultrasonic element can be adjusted by the first interval adjustment mechanism, even if the tube thickness is changed in the same way as before, the first ultrasonic element and the second ultrasonic element can be well attached to each tube, thereby enabling reliable bubble detection.

[0017] Meanwhile, since the pair of side guides facing each other across the tube are positioned in a direction intersecting the arrangement direction of the first and second ultrasonic elements, and the spacing between them is adjusted according to the diameter of the tube by the second spacing adjustment mechanism, it is possible to prevent the tube from being flattened into an elliptical shape by the first and second ultrasonic elements, and to deform the tube into a rectangular shape. As a result, it is possible to prevent the reduction of the flow path area inside the tube while ensuring the required flow rate. Attached Figure Description

[0018] Figure 1 This is a schematic circuit diagram of a blood purification device.

[0019] Figure 2 This is a perspective view of the detection box 11 containing the bubble detector 1 of the present invention.

[0020] Figure 3 This is an exploded perspective view of the bubble detector 1 of the present invention.

[0021] Figures 4(a) and 4(b) are cross-sectional views showing the initial state of bubble detector 1.

[0022] Figures 5(a) and 5(b) are cross-sectional views showing the state in which the bubble detector 1 is adjusted to fit the coarse tube 19.

[0023] Figures 6(a) and 6(b) are cross-sectional views showing the state in which the bubble detector 1 is adjusted to fit the capillary tube 19. Detailed Implementation

[0024] The present invention will now be described based on the illustrated embodiments. Figure 1 This is a schematic circuit diagram of a conventional blood purification device. The two bubble detectors 1 and 1 of the present invention, which are installed in the blood purification device, can detect the presence or absence of bubbles in the blood flowing in the blood circuit 2.

[0025] The aforementioned blood circuit 2 consists of an arterial side blood circuit 2A and a venous side blood circuit 2B. A puncture needle (not shown) is provided at one end of the arterial side blood circuit 2A and is connected to the patient. Furthermore, the other end of the arterial side blood circuit 2A is connected to one end of the dialyzer 5 via a blood pump 3 and an arterial side chamber 4.

[0026] The end of the aforementioned venous blood circuit 2B is connected to the other end of the dialyzer 5, and the front end of the venous blood circuit 2B is connected to the patient via the venous chamber 6 and a puncture needle (not shown).

[0027] Fresh dialysate is supplied into the dialyzer 5 from the dialysate supply circuit 7, and the dialysate supplied into the dialyzer 5 is discharged to the outside through the dialysate discharge circuit 8 connected to the dialyzer 5.

[0028] Although not illustrated, multiple hollow wires are provided inside the dialyzer 5, through which blood from the arterial side blood circuit 2A flows to the venous side blood circuit 2B.

[0029] In contrast, the dialysate supplied to dialyzer 5 flows outside the hollow line within dialyzer 5, separating the blood from the dialysate through the hollow line. Furthermore, waste products in the blood flowing within the hollow line are drawn out from inside the hollow line into the dialysate flowing outside, thereby purifying the blood.

[0030] This type of blood purification device is already known, so further explanation about the blood purification device will be omitted.

[0031] In this invention, one of the two bubble detectors 1, 1 is installed at the inlet side of the arterial blood circuit 2A, and the other bubble detector 1 is installed at the outlet side of the venous blood circuit 2B, which can detect the presence or absence of bubbles in the blood flowing in the blood circuits 2A and 2B respectively.

[0032] Figure 2 This is a perspective view of a detection box 11 containing the two bubble detectors 1, 1 mentioned above. The detection box 11 is detachable from the bracket 12 fixed to the front surface panel of the blood purification device (not shown). More specifically, the detection box 11 is a rectangular box shape, and its rear portion can be detachably fitted into a square recess 12a formed on the front surface of the bracket 12. It should be noted that, if necessary, an appropriate anti-detachment mechanism can be provided to prevent the detection box 11 from falling off the bracket 12.

[0033] The aforementioned testing box 11 has a rectangular box-shaped body 11A and a cover 11B that can be opened and closed via a hinge 13 provided on one side of the body 11A. When the cover 11B is closed, a latch 14 provided on the other side of the cover 11B engages with a locking pin 15 provided on the other side of the body 11A, thereby maintaining the cover 11B in a locked state.

[0034] Furthermore, by operating the latch 14 from the locked state, the engagement between the latch 14 and the locking pin 15 is released, thereby... Figure 2 The diagram shows that the cover 11B can be opened.

[0035] The main body 11A of the above-mentioned detection box 11 has two parallel tube grooves 18 arranged in the vertical direction, which can embed the tube 19 constituting the arterial blood circuit 2A into one tube groove 18 and embed the tube 19 constituting the venous blood circuit 2B into the other tube groove 18.

[0036] The two bubble detectors 1 mentioned above can detect bubbles in the blood flowing in the tubes 19 embedded in each tube groove 18.

[0037] Since both bubble detectors 1 have the same structure, the structure of only one bubble detector 1 will be described in detail below.

[0038] Figure 3 This is an exploded perspective view showing the bubble detector 1 described above, which includes a tube guide 21, the tube guide 21 having a cross-section. The test chamber has a letter-shaped portion 21A and two base portions 21B extending horizontally from its base. The two base portions 21B are fixed to the surface side (cover 11B side) of the main body 11A of the test chamber 11, with a cross-section... The inner surface of the character-shaped part 21A forms part of the aforementioned groove 18.

[0039] It should be noted that, in Figure 3 In the process, the tube groove 18 of the tube guide 21 is horizontal, but when the detection box 11 is installed in the bracket 12 of the blood purification device, the tube groove 18 of the tube guide 21 is oriented vertically, that is, with... Figure 3 The left side is configured as the top side.

[0040] In the cross-section of the aforementioned tube guide 21 Two guide pins 22 are provided parallel to each other at both ends of the upper surface of the character portion 21A along its length. By engaging the guide pins 22 with the two engaging holes 23a provided on the sensor block 23, the sensor block 23 can be moved along... Figure 3 The pipe guide 21 is installed vertically and horizontally.

[0041] A first ultrasonic element 24 is mounted on the lower surface of the aforementioned sensor block 23. The lower surface of the first ultrasonic element 24 is accessible through the cross-section of the aforementioned tube guide 21. The through hole 21a provided on the upper surface of the character part 21A is either inserted into the tube groove 18 of the tube guide 21 or exposed from the tube groove 18 of the tube guide 21.

[0042] On the other hand, Figure 2 The cover 11B shown is equipped with a second ultrasonic element 25. When the cover 11B is closed, the first ultrasonic element 24 and the second ultrasonic element 25 can face each other through the tube 19 embedded in the tube groove 18.

[0043] In this embodiment, the sensor block 23 constitutes a first support member supporting the first ultrasonic element 24, and the cover 11B constitutes a second support member supporting the second ultrasonic element 25. As described below, when the first ultrasonic element 24 and the second ultrasonic element 25 are facing each other, the distance between the first ultrasonic element 24 and the second ultrasonic element 25 can be adjusted by moving the sensor block 23, on which the first ultrasonic element 24 is mounted, forward and backward (up and down) along the guide pin 22.

[0044] Furthermore, the ultrasonic waves transmitted from either the first ultrasonic element 24 or the second ultrasonic element 25 are received by the other ultrasonic element, thereby enabling the detection of the presence of air bubbles in the blood flowing within the tube 19, as is known in the past.

[0045] exist Figure 3 In the bubble detector 1, a gate-shaped slider 28 is provided for moving the sensor block 23 up and down along the guide pin 22. The inner surfaces of the two legs 28A of the gate-shaped slider 28 are parallel to the cross-section of the tube guide 21. The opposing surfaces of the letter-shaped portion 21A make sliding contact, and the lower surfaces of the two legs 28A make sliding contact with the surface of the base portion 21B of the tube guide 21. Thus, the slider 28 is guided by each sliding contact surface and can move along the cross-section. The length direction of the character part 21A is the axial movement of the tube 19.

[0046] As shown in Figure 4(a), the upper surface of the slider 28 slides into contact with the inner surface of the wall 11a of the main body 11A of the detection box 11, thereby preventing the slider 28 from sliding from the tube guide 21 towards the inner surface of the detection box 11. Figure 3 The separation above. With the cover 11B closed, the wall portion 11a faces the cover 11B in parallel. With the detection box 11 embedded in the recess 12a of the bracket 12, the wall portion 11a is located on the inner surface side of the recess 12a.

[0047] like Figure 3 As shown in Figure 4(a), two adjusting screws 29 are screwed onto the end of the slider 28. Each adjusting screw 29 protrudes outward through an elongated hole 11b formed in the wall portion 11a of the main body 11A. The elongated hole 11b is formed along the length direction of the tube 19. By tightening each adjusting screw 29 at an appropriate position to move the slider 28 along the length direction, the slider 28 can be fixed to the wall portion 11a of the main body 11A, and thus fixed to the tube guide 21.

[0048] like Figure 3 As shown, the upper surface of the sensor block 23 is formed at an inclination along the length of the tube 19, and a first engaging portion 30 with a dovetail-shaped cross-section is provided on the inclination surface. On the other hand, the lower surface of the gate-shaped slider 28 located between the two legs 28A is also formed at an inclination along the inclination surface, and a first guide portion 31 with a dovetail-shaped cross-section that engages with the first engaging portion 30 is provided on the inclination surface.

[0049] The first engaging portion 30 and the first guiding portion 31 engage with each other at the dovetail-shaped portion of their cross-sections. They can slide relative to each other along the length of the inclined surface, but cannot separate in the vertical direction.

[0050] Therefore, by moving the slider 28 back and forth relative to the fixed tube guide 21 along the length of the tube 19, the sensor block 23 can be raised and lowered along the guide pin 22 by utilizing the tilt of the first engaging part 30 and the first guiding part 31.

[0051] Therefore, by bringing the first ultrasonic element 24 disposed on the sensor block 23 closer to or away from the second ultrasonic element 25 disposed on the cover 11B, the distance between the two can be adjusted.

[0052] Therefore, in this embodiment, a first interval adjustment mechanism for adjusting the interval between the first ultrasonic element 24 and the second ultrasonic element 25 is constituted by the slider 28, the first engaging part 30 and the first guiding part 31, and the guiding pin 22 and the engaging hole 23a.

[0053] Furthermore, the bubble detector 1 has a pair of side blocks 35 facing each other across the tube 19 in a transverse direction that intersects the arrangement direction of the first ultrasonic element 24 and the second ultrasonic element 25 which are vertically opposite each other across the tube 19, and the spacing between the two side blocks 35 can be adjusted according to the thickness of the tube 19.

[0054] The left and right base portions 21B of the tube guide 21 are respectively formed with guide holes 21b for engaging with the side blocks 35. Each side block 35 engages with the guide hole 21b and can move forward and backward along the diameter direction of the tube 19 and can protrude into the tube groove 18.

[0055] At the outer ends of each of the aforementioned side blocks 35, which are separated from each other, a second engaging portion 36 is formed that is inclined relative to the length direction of the tube 19. Each second engaging portion 36 has an outer protrusion 36a and an inner engaging groove 36b, the depth of which is the same as the height of the surface of the base portion 21B.

[0056] On the other hand, second guide portions 37 that engage with the second engaging portion 36 are respectively provided on the inner side of the lower surface of the two legs 28A of the gate-shaped slider 28. Each second guide portion 37 is inclined along the inclination of the second engaging portion 36 and has a protrusion 37a that engages with the engaging groove 36b of the second engaging portion 36 and an engaging groove 37b that engages with the protrusion 36a (see Figure 4(b)).

[0057] Therefore, by moving the slider 28 forward and backward relative to the tube guide 21 along the length of the tube 19, the two side blocks 35 can be brought closer or separated by the inclination of the second engaging part 36 and the second guiding part 37, thereby adjusting the gap between them.

[0058] At this time, the two side blocks 35 are close to or separated from the center line of the tube groove 18, so that the tube 19 embedded in the tube groove 18 can be clamped in a state that always keeps it in the center of the tube groove 18.

[0059] Furthermore, in this embodiment, the second interval adjustment mechanism for adjusting the interval of the side block 35 is formed by the slider 28, the second engaging part 36, and the second guiding part 37.

[0060] It should be noted that, as Figure 1 As shown, an arterial clamp 41 is provided upstream of the bubble sensor 1 on the arterial side, and a venous clamp 42 is provided downstream of the bubble sensor 1 on the venous side.

[0061] The clips 41 and 42 are not located on the test box 11 but on the blood purification device side. Although not shown in the figure, when the test box 11 is assembled on the bracket 12 on the blood purification device side, the front ends of each clip 41 and 42 protrude into the enlarged diameter portion 18a of the groove 18 formed in the main body 11A of the test box 11 and are located there.

[0062] That is, when the test box 11 is removed from the bracket 12, it can be removed from the bracket 12 with each clip 41, 42 remaining on the blood purification device side. On the other hand, when the test box 11 is assembled on the bracket 12, the front ends of each clip 41, 42 are located in the enlarged diameter portion 18a of the tube groove 18. Therefore, when the tube 19 is inserted into the tube groove 18, the tube 19 can be engaged with the front ends of each clip 41, 42. In this state, by operating each clip 41, 42, the tube 19 can be flattened to prevent blood flow. It should be noted that in this embodiment, the detection box 11 is removed from the bracket 12 while the clips 41 and 42 are retained on the side of the blood purification device. However, the detection box 11 and the bracket 12, or the detection box 11, the bracket 12 and the clip box with clips 41 and 42 can be integrated into one structure and removed from the front panel of the blood purification device to adjust the spacing between the first ultrasonic element 24 and the second ultrasonic element 25 and the side blocks 35.

[0063] In the above structure, the states shown in Figures 4(a) and 4(b) illustrate the initial state in which the slider 28 is positioned at the top of the figure relative to the tube guide 21. In this initial state, the first ultrasonic element 24 disposed on the sensor block 23 is located at the position furthest from the second ultrasonic element 25 disposed on the cover 11B (see Figure 4(a)). Moreover, at the same time, the pair of side blocks 35 are also located at the position furthest from each other (see Figure 4(b)).

[0064] When using, for example, the thick tube 19, starting from the initial state shown in Figures 4(a) and 4(b), first remove the test box 11 from the bracket 12, and then loosen the aforementioned adjusting screw 29 to move the slider 28 downward as shown in Figure 5(a).

[0065] Therefore, by engaging the first guide portion 31 provided on the slider 28 with the first engaging portion 30 provided on the sensor block 23, the sensor block 23 and the first ultrasonic element 24 installed on the sensor block 23 can be pressed out to the left in FIG. 5(a), thus narrowing the gap between the first ultrasonic element 24 and the second ultrasonic element 25 when the cover 11B is closed.

[0066] In addition, at the same time, if the slider 28 is moved downward in FIG5(a), as shown in FIG5(b), the gap between the pair of side blocks 35 can be narrowed by the engagement of the second guide portion 37 provided on the slider 28 and the second engaging portion 36 provided on the side block 35.

[0067] Although not shown, appropriate markings are marked on the side of the elongated hole 11b through which the adjusting screw 29 passes, at a position suitable for the diameter of the thick tube 19 used. By moving the adjusting screw 29 to the marked position and tightening it, the slider 28 is fixed to the wall 11a of the detection box 11, thereby allowing the first ultrasonic element 24 and the pair of side blocks 35 to be fixed in the most suitable positions suitable for the thick tube 19. It should be noted that, in addition to the marked markings, one end of the elongated hole may be set to a position suitable for the thick tube 19 and the other end to a position suitable for the thin tube 19, or holes of the same size as the tube may be formed, or a clamp of the same diameter as the tube may be used for adjustment, but there are no limitations to this.

[0068] After adjusting the position of the slider 28 to the most suitable position for the thick tube 19, the detection box 11 is installed in the recess 12a of the bracket 12 of the blood purification device.

[0069] In this state, by opening the cover 11B of the detection box 11, the tube 19 constituting the arterial side circuit 2A and the tube 19 constituting the venous side blood circuit 2B of the blood circuit 2 can be inserted into the tube groove 18 respectively. After inserting each tube 19 into the respective tube groove 18, the cover 11B can be closed.

[0070] In this state, the interval between the first ultrasonic element 24 and the second ultrasonic element 25, and the interval between the pair of side blocks 35 are respectively adjusted to the most suitable position for the thick tube 19, so that the thick tube 19 is clamped from the vertical and horizontal directions of its cross section and flattened into a rectangular shape.

[0071] Therefore, the first ultrasonic element 24 and the second ultrasonic element 25 can be well and tightly attached to the outer peripheral surface of the tube 19, thus enabling reliable bubble detection. Furthermore, since the tube 19 is flattened into a rectangular shape, a larger flow path area is ensured compared to the case where the tube 19 is flattened into an elliptical shape using only the first ultrasonic element 24 and the second ultrasonic element 25. This prevents the situation where the flow path area of ​​the tube 19 is reduced, resulting in insufficient blood volume.

[0072] Furthermore, starting from the initial state described above or the state in which the thick tube 19 is used, if the need to use the thin tube 19 as shown in Figures 6(a) and 6(b) arises, simply loosen the adjusting screw 29 as described above to move the slider 28 downward as shown in Figure 6(a), move the adjusting screw 29 to the marked position (not shown) on the side of the elongated hole 11b that corresponds to the thin tube 19, and tighten it.

[0073] As a result, the first ultrasonic element 24 can be pressed further to the left as shown in FIG6(a), and the gap between the pair of side blocks 35 can be narrowed further as shown in FIG6(b). Thus, the first ultrasonic element 24 and the pair of side blocks 35 can be adjusted to the most suitable position that is compatible with the thin tube 19.

[0074] In this case, the first ultrasonic element 24 and the second ultrasonic element 25 can be well attached to the outer peripheral surface of the thin tube 19 to reliably detect bubbles, and the thin tube 19 can be flattened into a rectangular shape, thus suppressing the reduction of the flow path area of ​​the tube 19.

[0075] It should be noted that in the above embodiments, by sliding the slider 28, the interval between the first ultrasonic element 24 and the second ultrasonic element 25, as well as the interval between the pair of side blocks 35, can be adjusted simultaneously. However, both can also be adjusted independently. More specifically, although not shown, for example, a position adjustment screw can be used as a first interval adjustment mechanism that allows the position of the sensor block 23 to move forward and backward, and is linked to the sensor block 23. The interval between the first ultrasonic element 24 and the second ultrasonic element 25 can be adjusted by moving the position of the sensor block 23 forward and backward using this position adjustment screw. On the other hand, a position adjustment screw can be used as a second interval adjustment mechanism that allows the position of at least one of the pair of side blocks 35 to move forward and backward, and is linked to at least one of the pair of side blocks 35. The interval between the two side blocks 35 can be adjusted by moving the position of at least one of the side blocks 35 forward and backward using this position adjustment screw.

[0076] [Explanation of Labels in the Attached Image]

[0077] 1. Bubble Detector

[0078] 11 Testing Box

[0079] 11A Main Body

[0080] 11B Cover (Second Support Member)

[0081] 18 Pipeline

[0082] 19 tubes

[0083] 21-tube guide

[0084] 23 Sensor block (first support member)

[0085] 24 First ultrasonic element

[0086] 25 Second ultrasonic element

[0087] 28 sliders

[0088] 29 Adjusting screw

[0089] 30 First Card Section

[0090] 31 First Guiding Department

[0091] 35 side blocks

[0092] 36 Second Card Section

[0093] 37 Second Guiding Section

Claims

1. A bubble detector, comprising: a first ultrasonic element disposed on a first support member; a second ultrasonic element disposed on a second support member and facing the first ultrasonic element across a tube; and a first interval adjustment mechanism that adjusts the interval between the first support member and the second support member to adjust the interval between the first ultrasonic element and the second ultrasonic element according to the diameter of the tube. Ultrasonic waves emitted from either the first or second ultrasonic element are received by the other ultrasonic element, thereby detecting the presence of air bubbles in a liquid flowing within a pipe. The air bubble detector is characterized in that… Along the radial direction of the tube, in the direction intersecting the first and second ultrasonic elements which are arranged facing each other across the tube, there is a pair of side guides facing each other across the tube. A second spacing adjustment mechanism is provided to adjust the spacing between the pair of side guides according to the diameter of the tube. The first and second spacing adjustment mechanisms are operated in such a way that the distance between the first and second ultrasonic elements and the distance between the pair of side guides are adjusted simultaneously. By holding the tube and flattening it into a rectangular shape, the first and second ultrasonic elements are made to fit tightly against the tube.

2. The bubble detector according to claim 1, characterized in that, The bubble detector comprises: a tube guide having a tube groove into which the tube can be detachably inserted; and a cover disposed on the tube guide, which allows the tube to be removed from or inserted into the tube groove when open, and covers the tube inserted into the tube groove when closed. The second support member is disposed on the cover, and the first support member is disposed on the tube guide in a radially movable manner along the tube embedded in the tube groove. The first interval adjustment mechanism moves the first support member radially along the tube to adjust the interval between the first ultrasonic element and the second ultrasonic element. In addition, the pair of side guides are respectively movably disposed on the tube guide along the radial direction of the tube embedded in the tube groove, and the second spacing adjustment mechanism causes each side guide to move radially along the tube to adjust the spacing between them according to the diameter of the tube.

3. The bubble detector according to claim 2, characterized in that, The first interval adjustment mechanism includes: a slider movable along the length of the tube groove; a first guide portion inclinedly disposed on the slider along the length of the tube groove; and a first engaging portion disposed on the first support member and engaging with the first guide portion of the slider. The first support member moves radially forward and backward along the tube by moving the slider along the length of the tube groove via the first guide and the first engaging part.

4. The bubble detector according to claim 3, characterized in that, The second interval adjustment mechanism includes: a pair of second guide portions, which are obliquely disposed on the slider along the length direction of the groove; and second engaging portions, which are respectively disposed on the pair of side guides and engage with the second guide portions respectively. By moving the slider along the length of the tube groove, a pair of side guides are moved radially forward and backward along the tube via the second guide and the second engaging part.

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