JP6912097B2 - Ultrasonic flowmeter - Google Patents

Description

The present invention relates to an ultrasonic flow meter that measures the flow rate of a liquid using ultrasonic waves.

Conventionally, various ultrasonic flowmeters for measuring the flow rate of a liquid have been proposed as measuring devices using ultrasonic waves (see, for example, Patent Documents 1 to 4). In this ultrasonic flowmeter, a flow rate measuring tube is provided in the middle of a tube through which a liquid flows, and ultrasonic sensors are installed at an upstream position and a downstream position of the flow measuring tube, respectively. Then, ultrasonic waves are transmitted and received using these ultrasonic sensors, and based on the time difference between the propagation time of the ultrasonic waves propagating from the upstream side to the downstream side and the propagation time of the ultrasonic waves propagating from the downstream side to the upstream side, The flow rate of the liquid is calculated. The flow rate measuring tube is used in a state of being attached to the ultrasonic flow meter. For example, Patent Document 1 discloses an ultrasonic flow meter to which a disposable flow measuring tube is detachably attached. Specifically, the flow measuring tube has a straight tube portion housed in the cavity of the holder, and at the end of the straight tube portion, an ultrasonic sensor also provided in the holder is applied by the urging force of the spring. It is designed to be pressed. Note that Patent Documents 2 to 4 do not disclose any structure that allows the flow rate measuring tube to be attached and detached.

U.S. Pat. No. 5,436,906 (Fig. 1, etc.) Japanese Patent No. 5548857 (Fig. 1 etc.) Japanese Unexamined Patent Publication No. 2007-58352 (FIGS. 1, FIG. 16 and the like) Japanese Unexamined Patent Publication No. 2008-128841 (see FIG. 1 etc.)

However, in the prior art described in Patent Document 1, when the straight pipe portion is housed in the cavity of the holder when the flow measuring pipe is attached, it is necessary to operate and press the slide bar against the urging force of the spring. There is. Moreover, the operation direction of the slide bar is different from the storage direction of the straight pipe portion. That is, there is a problem that it is difficult to attach the flow rate measuring tube because the operations in two directions must be performed at the same time. Further, in Patent Document 1, since the flow rate measuring tube is exposed from the opening of the cavity, if an unintended external force acts on the infusion tube connected to both ends of the flow measuring tube, the flow measuring tube may fall off from the holder. There is also.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrasonic flow meter capable of easily replacing the flow measuring tube and preventing the flow measuring tube from falling off. To do.

In order to solve the above problem, the invention according to claim 1 faces an upstream position and a downstream position of a flow measuring pipe provided in the middle of a pipe through which a liquid flows and having bent portions bent at right angles to both ends. A pair of ultrasonic sensors arranged and alternately propagating ultrasonic waves through the flow measuring tube, and an urging force for pressing the ultrasonic sensor against the bent portions on the upstream side and the downstream side of the flow measuring tube. A storage case for accommodating the flow measuring tube, the pair of ultrasonic sensors, and the urging member, and the propagation time of ultrasonic waves transmitted and received between the pair of ultrasonic sensors. An ultrasonic flowmeter that measures the flow rate of the liquid based on the difference. The storage case houses a measuring tube holder having a measuring tube storage portion and the ultrasonic sensor on the upstream side, and the measuring tube holder. The first sensor cover connected to the first end in the length direction of the tube and the ultrasonic sensor on the downstream side are housed and connected to the second end in the length direction of the measuring tube holder. The measuring pipe accommodating portion is configured to include the sensor cover of 2, and covers the periphery of the flow measuring pipe, and the end of the flow measuring pipe on the inflow port side and the end on the outflow side are the measuring pipe holder. The sensor cover on the side of the first sensor cover and the second sensor cover on which the urging member is not housed is detachably attached to the measuring tube holder. The gist of this is an ultrasonic flowmeter.

Therefore, according to the invention of claim 1, the flow rate measuring tube is moved along the length direction of the measuring tube holder, and the flow rate is entered into the measuring tube accommodating portion from the first end side or the second end side of the measuring tube holder. After storing the measuring tube, the flow rate measuring tube can be fixed by moving the first sensor cover and the second sensor cover in the same length direction and connecting them to the measuring tube holder. That is, since the storage of the flow rate measuring tube and the connection of the sensor cover are completed only by operating in one direction, the flow rate measuring tube can be easily attached and, by extension, the flow rate measuring tube can be easily replaced. Further, since the circumference of the flow rate measuring tube is covered by the measuring tube holder, for example, even if an unintended external force acts on the end of the flow measuring tube on the inflow port side or the end on the outflow port side, the measuring tube holder can be used. It is possible to prevent the flow rate measuring tube from falling off.

According to the second aspect of the present invention, in the first aspect, the flow rate measuring pipe has a straight pipe portion extending in a straight shape and has bent portions at both ends of the straight pipe portion. The measuring tube accommodating portion has a straight pipe accommodating portion for accommodating the straight pipe portion and a groove portion communicating with the straight pipe accommodating portion and opening on the peripheral surface of the measuring tube holder. When the sensor cover detachably attached to the measuring tube holder among the sensor cover and the second sensor cover is separated from the measuring tube holder, the first end side of the measuring tube holder or the said When the straight tube storage portion opens on the second end side and the sensor cover is connected to the measuring tube holder, the straight tube holder is on the first end side or the second end side of the measuring tube holder. The gist is that the pipe storage section is closed.

Therefore, according to the invention of claim 2, the flow rate measuring tube is moved along the length direction of the measuring tube holder, and the straight pipe portion of the flow measuring tube is housed in the straight pipe portion accommodating portion and in the groove portion. After storing the bent portion of the flow rate measuring pipe, the straight pipe portion can be fixed by connecting the sensor cover, which is detachably attached to the measuring pipe holder, to the measuring pipe holder. In this case, simply moving the flow measuring pipe along the length direction of the measuring pipe holder completes the storage of the straight pipe portion and the storage of the bent portion, which makes it easier to install the flow measuring pipe. It can be carried out.

The gist of the invention according to claim 3 is that the width of the groove portion is smaller than the inner diameter of the straight pipe portion accommodating portion in claim 2.

Therefore, according to the invention of claim 3, the width of the groove portion can be made smaller than the outer diameter of the straight pipe portion housed in the straight pipe portion accommodating portion. In this case, the straight pipe portion is prevented from falling off from the straight pipe portion accommodating portion through the groove portion.

In the invention according to claim 4, in any one of claims 1 to 3, the measuring tube holder has a holder-side contactor, and the first sensor cover and the second sensor cover are described above. The sensor cover detachably attached to the measuring tube holder has a cover-side contactor, and the holder-side contactor and the cover-side contactor are connected to the measuring tube holder. The gist is that they are placed facing each other so that they come into contact with each other.

Therefore, according to the fourth aspect of the present invention, when an ultrasonic sensor housed in a sensor cover detachably attached to a measuring tube holder is connected to a cover-side contactor via internal wiring, It is possible to prevent the internal wiring from being exposed to the outside of the sensor cover. Therefore, it is possible to solve the problem that the pipe is caught in the internal wiring.

Further , according to the first aspect of the present invention, the sensor cover attached to and detached from the measuring tube holder has a simple structure in which the urging member is not housed, so that the weight is reduced. As a result, the usability of the ultrasonic flowmeter is improved.

Both the first sensor cover and the second sensor cover may be detachably attached to the measuring tube holder.

In this way , the flow rate measuring tube can be replaced regardless of whether the first sensor cover is removed or the second sensor cover is removed. Therefore, the ultrasonic flow rate can be changed. The usability of the total is further improved.

The gist of the invention according to claim 5 is that, in any one of claims 1 to 4 , the measuring tube holder is made of a transparent material.

Therefore, according to the fifth aspect of the present invention, when the flow rate measuring tube is stored in the measuring tube accommodating portion of the measuring tube holder, it becomes easy to check the state of the liquid flowing in the flow rate measuring tube. Here, as the transparent material for forming the measuring tube holder, a resin material such as ABS resin (acrylonitrile butadiene styrene resin), PC resin (polycarbonate resin), PET resin (polyethylene terephthalate resin) can be used.

The invention according to claim 6 is the sensor according to any one of claims 1 to 5 , which is detachably attached to the measuring tube holder among the first sensor cover and the second sensor cover. The gist of the cover is that it is a screw type cap that is connected to the measuring tube holder by rotating it.

Therefore, according to the invention of claim 6 , since the sensor cover detachably attached to the measuring tube holder is a screw type cap, the connection strength between the measuring tube holder and the sensor cover is improved. Moreover, a connecting member such as a screw used for connecting the measuring tube holder and the sensor cover becomes unnecessary. Therefore, a high-strength connected structure can be realized at low cost.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the first sensor cover or the second sensor cover is provided with a display device for displaying the flow rate of the liquid. That is the gist.

Therefore, according to the invention of claim 7 , the operator can confirm whether or not there is an abnormality in the flow rate of the liquid by confirming the display on the display device.

The gist of the invention according to claim 8 is that, in any one of claims 1 to 7 , the flow rate measuring tube is provided in the middle of an infusion tube through which an infusion solution which is a liquid flows.

Therefore, according to the invention of claim 8 , since the flow rate measuring tube is provided in the middle of the infusion tube through which the infusion solution flows, ultrasonic waves are efficiently propagated into the infusion solution from the ultrasonic sensor via the flow rate measuring tube. Therefore, ultrasonic measurements such as infusion flow rate measurement can be performed reliably. Further, since the infusion tube is thin, the flow rate measuring tube connected to the infusion tube can be formed thin. In this case, as the ultrasonic sensor, for example, a small sensor having a diameter of 15 mm or less can be used, so that the ultrasonic flowmeter can be compactly formed.

The invention described in section 1, the measurement pipe holder, both the first sensor cover及beauty second sensor cover is detachably mounted, a plurality of types of the different according to the shape and size of the flow measurement tube leave preparing measurement tube holder beforehand, a preparation selecting step of selecting one of the measurement pipe holder from them depending on the shape and size of the flow measurement tube, with respect to the measuring tube holder chosen, the tube It includes an assembly step of accommodating the flow rate measuring tube provided in the middle and connecting the first sensor cover and the second sensor cover, and a measurement step of measuring the flow rate after the assembly step. The gist is how to use the ultrasonic flowmeter.

Therefore, according to the invention described in the means 1 , in the assembly process, the flow rate measuring tube is moved along the length direction of the measuring tube holder, and the flow rate measuring tube is stored in the measuring tube holder, and then the first The flow rate measuring tube can be fixed by moving the sensor cover and the second sensor cover in the same length direction and connecting them to the measuring tube holder. That is, since the storage of the flow rate measuring tube and the connection of the sensor cover are completed only by operating in one direction, the flow rate measuring tube can be easily attached and, by extension, the flow rate measuring tube can be easily replaced. Further, since the flow rate measuring tube is housed in the measuring tube holder to cover the periphery of the flow rate measuring tube, for example, even if an unintended external force acts on the tube provided with the flow rate measuring tube, the flow rate is measured from the measuring tube holder. It is possible to prevent the pipe from falling off.

Moreover, in the preparation selection step, a plurality of types of measuring tube holders different according to the shape and dimensions of the flow measuring tube are prepared in advance, and one measuring tube holder is prepared from among them according to the shape and dimensions of the flow measuring tube. Therefore, the desired flow rate measuring tube can be easily attached. Further, when replacing the flow rate measuring tube, only the measuring tube holder is replaced and the first sensor cover and the second sensor cover are used as they are, so that the component cost is reduced as compared with the case where the entire storage case is replaced. can do.

As described above in detail, according to the invention described in claim 1-8, the exchange of flow measurement tube can be easily performed, and provide an ultrasonic flow meter can be prevented from falling off of the flow measurement tube can do.

The schematic block diagram which shows the infusion system of 1st Embodiment. The perspective view which shows the ultrasonic flow meter. Sectional drawing which shows the ultrasonic flow meter. An exploded perspective view showing an ultrasonic flow meter. A block diagram showing the electrical configuration of an infusion system. The perspective view which shows the ultrasonic flow meter of the 2nd Embodiment. Sectional drawing which shows the ultrasonic flow meter. An exploded perspective view showing a configuration near the first sensor cover of the storage case. Sectional drawing which shows the ultrasonic flowmeter of another embodiment. The front view which shows the flow rate measuring tube of another embodiment. The perspective view which shows the ultrasonic flowmeter of another embodiment. The perspective view which shows the ultrasonic flowmeter of another embodiment. The schematic block diagram which shows the infusion system of another embodiment. (A) and (b) are front views showing the measuring tube holder and the flow rate measuring tube of another embodiment.

[First Embodiment]
Hereinafter, the first embodiment in which the present invention is embodied in an infusion system will be described in detail with reference to the drawings.

As shown in FIG. 1, the infusion system 1 of the present embodiment includes an infusion tube 2 which is a tube through which an infusion solution W1 (a liquid such as a chemical solution) flows. The infusion tube 2 is a transparent tube having flexibility, and its outer diameter is, for example, about 3 mm. Further, the infusion tube 2 has an infusion bag 3 connected to the base end and a syringe 4 attached to the tip end. Therefore, the infusion solution W1 is administered from the infusion tube 2 to the vein or the like of the patient 5 via the syringe 4. As the material for forming the infusion tube 2, BDR resin (polybutadiene resin), PU resin (polyurethane resin), PO resin (polyolefin resin), PTFE resin (polytetrafluoroethylene resin), silicone rubber and the like can be used. ..

Further, a clamp 6 (adjustment knob) is installed in the middle of the infusion tube 2. The clamp 6 has a roller (not shown) slidable in the axial direction of the infusion tube 2. The clamp 6 switches the flow path in the infusion tube 2 between a closed state and an open state by operating a roller. Further, the clamp 6 is configured so that the flow velocity and the flow rate of the infusion solution W1 can be adjusted according to the amount of operation of the roller in the open state. Further, a pump device 7 (liquid feeding means) for sending the infusion W1 in the infusion bag 3 toward the tip of the infusion tube 2 is installed at a position between the infusion bag 3 and the clamp 6 in the infusion tube 2. There is.

Then, in the middle of the infusion tube 2, specifically, a flow rate measuring tube 11 is provided at a position between the infusion bag 3 and the pump device 7 in the infusion tube 2. The flow rate measuring tube 11 of the present embodiment is formed by using a transparent resin material such as a polycarbonate resin. As shown in FIGS. 2 to 4, an upstream portion (a portion on the infusion bag 3 side) of the infusion tube 2 is connected to the end portion of the flow rate measuring tube 11 on the inflow port 12 (see FIG. 3) side. A downstream portion (portion on the pump device 7 side) of the infusion tube 2 is connected to the end portion of the flow rate measuring pipe 11 on the outlet 13 (see FIGS. 2 and 3) side. In the flow rate measuring pipe 11 of the present embodiment, the infusion solution W1 flows from the inflow port 12 toward the outflow port 13.

Further, the flow rate measuring pipe 11 has a straight pipe portion 14 extended in a straight shape, and has bent portions 15 and 16 at both ends of the straight pipe portion 14, respectively. The bent portion 15 on the upstream side is connected to the upstream end portion of the straight pipe portion 14, has a shape bent at a right angle to the straight pipe portion 14, and has an inflow port 12 at the tip. The bent portion 16 on the downstream side is connected to the downstream end portion of the straight pipe portion 14, has a shape bent at a right angle to the straight pipe portion 14, and has an outlet 13 at the tip. The flow rate measuring pipe 11 of the present embodiment has a shape (crank shape) in which the bent portion 15 on the upstream side and the bent portion 16 on the downstream side are bent in opposite directions via the straight pipe portion 14.

As shown in FIG. 1, an ultrasonic flow meter 20 in which a flow measuring tube 11 is housed is installed at a position between the infusion bag 3 and the pump device 7 in the infusion tube 2. The ultrasonic flow meter 20 is for measuring the flow rate of the infusion solution W1 flowing through the infusion tube 2 by the ultrasonic propagation time difference method, for example, in a medical field.

As shown in FIGS. 3 and 4, the ultrasonic flow meter 20 includes a pair of ultrasonic sensors 21 and 22. Both ultrasonic sensors 21 and 22 are arranged so as to face each other via a straight pipe portion 14 of the flow rate measuring pipe 11. Specifically, the first ultrasonic sensor 21 is provided at a position on the upstream side of the straight pipe portion 14, and the second ultrasonic sensor 22 is provided at a position on the downstream side of the straight pipe portion 14. Both ultrasonic sensors 21 and 22 are sensors having the same structure. Specifically, the ultrasonic sensors 21 and 22 are small sensors having a diameter of 10 mm, and have a convex curved ultrasonic radiation surface 23 at the tip. Further, the ultrasonic sensors 21 and 22 include a cap-shaped sensor case 25 having a flange portion 24 at the base end portion and an ultrasonic vibrator (not shown) built in the sensor case 25 capable of transmitting and receiving ultrasonic waves. It has. The ultrasonic vibrator is a piezoelectric element formed in a disk shape, a square plate shape, or the like by using a piezoelectric ceramic such as lead zirconate titanate (PZT).

Since the vibration surface of the ultrasonic vibrator is adhered to the inner surface of the tip of the sensor case 25, the outer surface of the tip becomes the ultrasonic radiation surface 23. The outer surface of the tip of the sensor case 25 is covered with a rubber sheet 26. Therefore, in the first ultrasonic sensor 21, ultrasonic waves are emitted from the ultrasonic radiation surface 23 in a state where the ultrasonic radiation surface 23 is pressed against the base end portion of the bent portion 15 of the flow rate measuring tube 11 via the rubber sheet 26. Will radiate. Similarly, the second ultrasonic sensor 22 superimposes from the ultrasonic radiation surface 23 in a state where the ultrasonic radiation surface 23 is pressed against the base end portion of the bent portion 16 of the flow rate measuring tube 11 via the rubber sheet 26. It will emit ultrasonic waves. Further, two internal wires 27a are connected to the ultrasonic vibrator of the first ultrasonic sensor 21, and two internal wires (not shown) are connected to the ultrasonic vibrator of the second ultrasonic sensor 22. It is connected. The internal wiring 27a connected to the ultrasonic transducer of the first ultrasonic sensor 21 is pulled out from the central portion of the outer surface of the base end portion of the sensor case 25. Further, the internal wiring connected to the ultrasonic vibrator of the second ultrasonic sensor 22 is drawn out from the central portion of the outer surface of the base end portion of the sensor case 25 and bound by the wiring tube 28.

As shown in FIGS. 3 and 4, the ultrasonic flow meter 20 includes a spring unit 31 (a urging member). The spring unit 31 presses the ultrasonic radiation surface 23 of the first ultrasonic sensor 21 against the bent portion 15 on the upstream side, and the ultrasonic radiation surface 23 of the second ultrasonic sensor 22 is pressed against the bent portion 16 on the downstream side. It is designed to give a urging force to push. Further, the spring unit 31 includes a compression spring 32, a cap 33, a pressure adjusting screw 34, and the like. The cap 33 has a substantially cylindrical shape and has a convex portion 35 on the inner surface side (upper surface side in FIG. 3). Further, the cap 33 is formed through a spring accommodating hole 36 for accommodating the base end portion of the compression spring 32. The spring accommodating hole 36 extends along the axial direction at the center of the cap 33. Further, a pressure adjusting screw 34 is screwed into the spring accommodating hole 36. The pressure adjusting screw 34 has a function of pressing the compression spring 32 from the base end side via the annular spacer 37 (copper plate). By changing the screwing amount of the pressure adjusting screw 34, the pressing amount for pressing the compression spring 32 can be adjusted. Further, a through hole 34a extending along the axial direction of the pressure adjusting screw 34 is provided in the central portion of the pressure adjusting screw 34. On the other hand, the tip of the compression spring 32 is in contact with the second sensor fixing member 69 via the annular spacer 38 (copper plate), and the urging force of the compression spring 32 is passed through the second sensor fixing member 69. It acts on the second ultrasonic sensor 22.

As shown in FIGS. 2 to 4, the ultrasonic flow meter 20 includes a flow measuring tube 11, an ultrasonic sensor 21 and 22, and a storage case 41 for accommodating a spring unit 31. The storage case 41 has a substantially cylindrical shape, and includes a measuring tube holder 42, a first sensor cover 51, and a second sensor cover 61.

The measuring tube holder 42 is formed in a substantially cylindrical shape using a transparent resin material such as polycarbonate resin. The measuring pipe holder 42 has a measuring pipe accommodating portion 43 that covers the circumference of the flow measuring pipe 11 and exposes the end of the flow measuring pipe 11 on the inflow port 12 side and the end on the outflow port 13 side to the outer peripheral surface 42c. ing. The measuring pipe accommodating portion 43 includes a straight pipe accommodating portion 44 for accommodating the straight pipe portion 14 of the flow measuring pipe 11, a groove portion 45 accommodating the bent portion 15 on the upstream side of the flow measuring pipe 11, and the flow measuring pipe 11. It has a groove 46 for accommodating the bent portion 16 on the downstream side. The straight pipe portion accommodating portion 44 includes a small diameter portion 47 and large diameter portions 48 and 49 located at the upstream side end portion and the downstream side end portion of the small diameter portion 47, respectively. A straight pipe portion 14 is arranged in the small diameter portion 47. Further, the upstream end of the straight pipe portion 14 and the base end of the bent portion 15 are arranged on the large diameter portion 48 on the upstream side, and the base end of the bent portion 16 is arranged on the large diameter portion 49 on the downstream side. The part is arranged.

As shown in FIGS. 2 to 4, the groove portions 45 and 46 are arranged on opposite sides to each other via the straight pipe portion accommodating portion 44. Each of the grooves 45 and 46 has a U shape that opens at the first end 42a of the measuring tube holder 42. Further, the groove portion 45 communicates with the large diameter portion 48 of the straight pipe portion accommodating portion 44 and opens at the outer peripheral surface 42c of the measuring tube holder 42. On the other hand, the groove portion 46 communicates with the entire straight pipe portion accommodating portion 44 and opens at the outer peripheral surface 42c of the measuring tube holder 42. Therefore, the depth of the groove 46 (the length of the measuring tube holder 42 in the axial direction) is larger than the depth of the groove 45. Further, the widths of the groove portions 45 and 46 are equal to each other and smaller than the inner diameter of the straight pipe portion accommodating portion 44.

As shown in FIGS. 3 and 4, a pair of communication holes 71 for communicating the first end 42a side and the second end 42b side of the measuring tube holder 42 are provided on the outer peripheral portion of the measuring tube holder 42. There is. Both communication holes 71 are arranged on opposite sides to each other via the straight pipe portion accommodating portion 44. A holder-side contactor 72 is attached to the opening on the first end 42a side of each communication hole 71. The holder-side contact 72 is connected to one end of the internal wiring 27b inserted into the communication hole 71.

Further, the holder-side contactor 72 includes a main body portion 72a and a pin 72b that can appear and disappear with respect to the main body portion 72a. When the first sensor cover 51 is connected to the measuring tube holder 42, the pin 72b comes into contact with the cover-side contactor 82 so as to move in the direction of immersion in the main body 72a (downward in FIG. 3). It has become. Further, the pin 72b is urged by a coil spring (not shown) in the main body 72a by being separated from the cover side contactor 82 when the first sensor cover 51 is separated from the measuring tube holder 42. It moves in the direction protruding from 72a (upward in FIG. 3).

As shown in FIGS. 2 to 4, the first sensor cover 51 houses the first ultrasonic sensor 21 and is connected to the first end 42a of the measuring tube holder 42. The first sensor cover 51 is a screw cap that is formed by using a resin material such as POM resin (polyacetal resin) and is connected to the measuring tube holder 42 by rotating.

Further, a first sensor holder 52 having a substantially cylindrical shape is attached to the first sensor cover 51. The first sensor holder 52 is provided with a storage hole 55 that communicates the front end surface 53 and the rear end surface 54, and the storage hole 55 houses the first ultrasonic sensor 21. As shown in FIG. 3, the storage hole 55 includes a small diameter portion 56 and a large diameter portion 57 located on the rear end surface 54 side of the small diameter portion 56. A stepped surface 58 for locking the flange portion 24 of the first ultrasonic sensor 21 is formed at the connecting portion between the small diameter portion 56 and the large diameter portion 57. A first sensor fixing member 59 forming an annular shape is screwed into the large diameter portion 57 of the storage hole 55. The first sensor fixing member 59 presses the first ultrasonic sensor 21 from the base end side, and the tip portion (ultrasonic radiation surface 23) of the first ultrasonic sensor 21 is pressed by the first sensor holder 52. It is fixed so as to protrude from the front end surface 53. Further, two internal wirings 27a connected to the ultrasonic vibrator of the first ultrasonic sensor 21 are inserted into the through hole 59a of the first sensor fixing member 59.

With the first ultrasonic sensor 21 fixed to the first sensor holder 52, the screw 52b is inserted into the screw hole 52a provided in the first sensor holder 52, and the tip of the inserted screw 52b is inserted. It is screwed onto the first sensor cover 51 (see FIG. 4). As a result, the first sensor holder 52 can be attached to the first sensor cover 51.

As shown in FIGS. 3 and 4, a pair of through holes 81 extending along the axial direction of the first sensor holder 52 are provided on the outer peripheral portion of the first sensor holder 52. Both through holes 81 are arranged on opposite sides to each other via the storage holes 55. A cover-side contactor 82 is attached to each through hole 81. The cover-side contact 82 is connected to one end of the internal wiring 27a extending from the first ultrasonic sensor 21. The cover-side contactor 82 is arranged to face the holder-side contactor 72 so that when the first sensor cover 51 is connected to the measuring tube holder 42, the cover-side contactor 82 comes into contact with the pin 72b of the holder-side contactor 72. There is.

As shown in FIGS. 2 to 4, the second sensor cover 61 is for accommodating the second ultrasonic sensor 22 and the spring unit 31. The second sensor cover 61 is formed by using a resin material such as POM resin. Further, the first end 61a of the second sensor cover 61 is connected to the second end 42b of the measuring tube holder 42. Specifically, the screw 61c is inserted into a screw hole (not shown) provided in the second sensor cover 61, and the tip of the inserted screw 61c is screwed into the measuring tube holder 42 (see FIG. 4). .. As a result, the second sensor cover 61 can be attached to the measuring tube holder 42.

Further, the second sensor cover 61 houses a second sensor holder 62 having a substantially cylindrical shape. The second sensor holder 62 is provided with a storage hole 65 that communicates the front end surface 63 and the rear end surface 64, and the storage hole 65 houses the second ultrasonic sensor 22. As shown in FIG. 3, the storage hole 65 includes a small diameter portion 66 and a large diameter portion 67 located on the rear end surface 64 side of the small diameter portion 66. A stepped surface 68 for locking the flange portion 24 of the second ultrasonic sensor 22 is formed at the connecting portion between the small diameter portion 66 and the large diameter portion 67. A second sensor fixing member 69 having a substantially cylindrical shape is screwed into the large diameter portion 67 of the storage hole 65. The second sensor fixing member 69 presses the second ultrasonic sensor 22 from the base end side, and also presses the tip end portion (ultrasonic radiation surface 23) of the second ultrasonic sensor 22 from the second sensor holder 62. It is fixed so as to protrude from the front end surface 63 of the. Further, the internal wiring connected to the ultrasonic vibrator of the second ultrasonic sensor 22 and the wiring tube 28 are inserted into the through hole 69a of the second sensor fixing member 69.

As shown in FIGS. 3 and 4, the outer peripheral portion of the second sensor cover 61 extends along the axial direction of the second sensor cover 61 and communicates with the communication hole 71 of the measuring tube holder 42. A pair of communication holes 73 are provided. Both communication holes 73 are arranged on opposite sides to each other via the storage holes 65. An internal wiring 27b extending from an opening on the second end 42b side of the communication hole 71 is inserted into each communication hole 73.

Further, as shown in FIGS. 2 to 4, the opening on the second end 61b side of the second sensor cover 61 is closed by the cap 33 of the spring unit 31 described above. Then, with the convex portion 35 fitted into the opening on the second end 61b side of the second sensor cover 61, the screw 33b is inserted into the screw hole 33a provided on the outer peripheral portion of the cap 33, and the inserted screw 33b The tip portion is screwed onto the second sensor cover 61. As a result, the cap 33 can be attached to the second sensor cover 61.

As shown in FIGS. 3 and 4, a pair of communication holes 74 extending along the axial direction of the cap 33 and communicating with the communication holes 73 of the second sensor cover 61 are provided on the outer peripheral portion of the cap 33. Has been done. Both communication holes 74 are arranged on opposite sides to each other via the spring storage holes 36 described above. An internal wiring 27b extending from an opening on the second end 61b side of the communication hole 73 is inserted into each communication hole 74.

Therefore, the internal wiring 27b connected to the holder-side contact 72 described above inserts the communication hole 71 of the measuring tube holder 42, the communication hole 73 of the second sensor cover 61, and the communication hole 74 of the cap 33 in this order. Then, it is pulled out to the outside of the ultrasonic flow meter 20. Then, the internal wiring 27b drawn out to the outside of the ultrasonic flow meter 20 is connected to the measurement control device 90 (see FIG. 5). Further, the internal wiring connected to the second ultrasonic sensor 22 described above is bound to the wiring tube 28, and the through hole 69a of the second sensor fixing member 69, the inner space of the compression spring 32, and the cap 33. The spring accommodating hole 36 and the through hole 34a of the pressure adjusting screw 34 are sequentially inserted and pulled out to the outside of the ultrasonic flow meter 20. Then, the internal wiring connected to the second ultrasonic sensor 22 and drawn out to the outside of the ultrasonic flow meter 20 is connected to the measurement control device 90. The internal wiring 27b connected to the first ultrasonic sensor 21 and the internal wiring connected to the second ultrasonic sensor 22 are bound to a wiring tube (not shown) outside the ultrasonic flow meter 20. Will be done.

In the present embodiment, of the two sensor covers 51 and 61 constituting the storage case 41, the first sensor cover 51 on the side where the spring unit 31 is not stored can be attached to and detached from the measuring tube holder 42. It is attached to. More specifically, when the first sensor cover 51 is separated from the measuring tube holder 42, the cover-side contactor 82 and the holder-side contactor 72 are separated from each other, and the first ultrasonic sensor 21 and the measurement control are controlled. The internal wiring 27 connecting the device 90 is separated into an internal wiring 27a and an internal wiring 27b. Therefore, the first sensor cover 51 can be attached to and detached from the measuring tube holder 42. On the other hand, the internal wiring 27 is not separated at the connecting portion between the second sensor cover 61 and the measuring tube holder 42. Therefore, the second sensor cover 61 cannot be attached to or detached from the measuring tube holder 42.

Next, the electrical configuration of the infusion system 1 will be described.

As shown in FIG. 5, the measurement control device 90 of the infusion system 1 is a device for calculating the flow rate of the infusion solution W1 according to the propagation time difference of the ultrasonic waves transmitted and received by the ultrasonic sensors 21 and 22. .. The measurement control device 90 includes a signal processing unit 91, an arithmetic processing unit 92, an input device 93, a display device 94, and the like. The signal processing unit 91 includes a circuit that outputs a drive signal for driving each ultrasonic sensor 21 and 22, a circuit that detects the propagation time of ultrasonic waves, and the like. The arithmetic processing unit 92 is a processing circuit configured to include a conventionally known CPU 95, a memory 96, and the like. A control program and data are stored in the memory 96, and the CPU 95 performs flow rate calculation processing and display processing based on the control program stored in the memory 96.

More specifically, the signal processing unit 91 alternately propagates ultrasonic waves through the flow rate measuring tube 11 by driving the ultrasonic sensors 21 and 22. Then, the signal processing unit 91 propagates the ultrasonic waves transmitted from the first ultrasonic sensor 21 and received by the second ultrasonic sensor 22 in the positive direction (propagating in the same direction as the infusion solution W1 flows). Ultrasonic propagation time) is detected. Further, the signal processing unit 91 propagates the ultrasonic waves transmitted from the second ultrasonic sensor 22 and received by the first ultrasonic sensor 21 in the opposite direction (propagation in the direction opposite to the direction in which the infusion solution W1 flows). The propagation time of ultrasonic waves) is detected. Then, the signal processing unit 91 outputs the propagation time in the forward direction and the propagation time in the reverse direction to the arithmetic processing unit 92. The arithmetic processing unit 92 takes in the propagation time in the forward direction and the propagation time in the reverse direction output from the signal processing unit 91, and calculates the flow rate of the infusion solution W1 by calculation based on the difference in the propagation times.

Further, as shown in FIG. 5, the input device 93 has various operation buttons to start / end the measurement, set the display mode, and the like. The display device 94 is, for example, a liquid crystal display, and displays the flow rate calculated by the arithmetic processing unit 92.

Next, how to use the ultrasonic flow meter 20 will be described.

Since the flow rate measuring tube 11 attached to the ultrasonic flow meter 20 of the present embodiment is a disposable flow measuring tube, it needs to be replaced regularly. Therefore, a method of replacing the flow rate measuring tube 11 will be described below. Specifically, first, the first sensor cover 51 is rotated counterclockwise to separate it from the measuring tube holder 42, and the straight tube portion accommodating portion 44 and the groove portion are provided on the first end 42a side of the measuring tube holder 42. Open 45 and 46. Next, the flow rate measuring tube 11 is taken out from the measuring tube accommodating portion 43 of the measuring tube holder 42. Then, after removing the infusion tube 2 from the bent portions 15 and 16 of the flow rate measuring tube 11, the removed infusion tube 2 is attached to the bent portions 15 and 16 of another flow measuring tube 11 prepared in advance. ..

Next, an assembly step is performed, the flow rate measuring tube 11 provided in the middle of the infusion tube 2 is housed in the measuring tube holder 42, and the first sensor cover 51 is connected to the measuring tube holder 42. Specifically, the flow rate measuring tube 11 is moved along the axial direction (length direction) of the measuring tube holder 42, and the flow rate measuring tube 11 is moved into the measuring tube accommodating portion 43 from the first end 42a side of the measuring tube holder 42. To store. At this time, the straight pipe portion 14 is housed in the straight pipe portion accommodating portion 44, the bent portion 15 is housed in the groove portion 45, and the bent portion 16 is housed in the groove portion 46. Next, the first sensor cover 51 is placed near the opening on the first end 42a side of the measuring tube holder 42, and in this state, the first sensor cover 51 is rotated in the clockwise direction. As a result, the first sensor cover 51 moves along the axial direction of the measuring tube holder 42 and is connected to the measuring tube holder 42, and the straight tube portion accommodating portion 44 is on the first end 42a side of the measuring tube holder 42. And the grooves 45 and 46 are closed. At this point, the replacement of the flow rate measuring tube 11 is completed.

In the measurement process after the assembly process, the flow rate is measured. Specifically, the signal processing unit 91 has a positive propagation time of ultrasonic waves transmitted from the first ultrasonic sensor 21 and received by the second ultrasonic sensor 22 (positive with respect to the flow of the infusion solution W1). The propagation time of ultrasonic waves propagating in a direction) is measured. Further, the signal processing unit 91 propagates the ultrasonic waves transmitted from the second ultrasonic sensor 22 and received by the first ultrasonic sensor 21 in the opposite direction (propagating in the opposite direction to the flow of the infusion solution W1). Measure the propagation time of ultrasonic waves). Then, the arithmetic processing unit 92 calculates the flow velocity of the infusion solution W1 based on the difference between the measured propagation time in the forward direction and the propagation time in the reverse direction, and converts the calculated flow velocity of the infusion solution W1 to convert the infusion solution. Calculate the flow rate of W1.

Then, the arithmetic processing unit 92 outputs the calculated flow rate data to the display device 94, and displays the flow rate of the infusion solution W1 on the display screen of the display device 94. Further, the arithmetic processing unit 92 compares the calculated flow rate with the flow rate set by the input device 93, and if the flow rates are different, determines that the flow rate is abnormal and controls the display device 94 to display the abnormality. conduct.

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

(1) In the ultrasonic flow meter 20 of the present embodiment, the flow rate measuring tube 11 is moved along the axial direction of the measuring tube holder 42, and the inside of the measuring tube accommodating portion 43 is moved from the first end 42a side of the measuring tube holder 42. The flow rate measuring tube 11 is housed in. Then, the flow rate measuring tube 11 can be fixed by moving the first sensor cover 51 along the axial direction of the measuring tube holder 42 and connecting the first sensor cover 51 to the measuring tube holder 42. That is, the storage of the flow rate measuring tube 11 and the connection of the first sensor cover 51 are completed only by operating in one direction (the axial direction of the measuring tube holder 42). , The flow rate measuring tube 11 can be easily replaced. Further, in the present embodiment, the circumference of the flow rate measuring tube 11 is covered by the measuring tube holder 42. Therefore, for example, even if an unintended external force acts on the end of the flow rate measuring tube 11 on the inflow port 12 side or the end on the outflow port 13 side due to pulling of the infusion tube 2, the measuring tube holder 42 It is possible to prevent the flow rate measuring tube 11 from falling off.

(2) By the way, in the ultrasonic flow meter described in Patent Document 1, since the slide bar is provided so as to protrude from the holder, the infusion tube may be caught in the slide bar. On the other hand, since the ultrasonic flow meter 20 of the present embodiment does not have a protrusion such as a slide bar, the problem that the infusion tube 2 is caught by the ultrasonic flow meter 20 is less likely to occur.

(3) In the present embodiment, the ultrasonic radiation surface 23 of the first ultrasonic sensor 21 is pressed against the bent portion 15 on the upstream side of the flow measuring tube 11 by the urging force of the spring unit 31, and the second ultrasonic sensor 21 is pressed. The ultrasonic radiation surface 23 of the ultrasonic sensor 22 is pressed against the bent portion 16 on the downstream side of the flow measuring tube 11. As a result, the flow rate measuring tubes 11 are clamped by the ultrasonic sensors 21 and 22. Further, the ultrasonic radiation surfaces 23 of the ultrasonic sensors 21 and 22 are brought into close contact with the flow rate measuring tube 11 via the rubber sheet 26. Therefore, ultrasonic waves can be efficiently propagated from the ultrasonic radiation surfaces 23 of the ultrasonic sensors 21 and 22 into the infusion solution W1 in the flow rate measuring tube 11, and the flow rate of the infusion solution W1 can be reliably measured.

(4) In the present embodiment, the internal wiring 27a connecting the first ultrasonic sensor 21 and the cover-side contactor 82 is not exposed to the outside of the storage case 41. Further, the internal wiring 27b connecting the holder side contactor 72 and the measurement control device 90 is pulled out from the communication hole 74 of the cap 33 to the outside of the storage case 41 so as not to be exposed on the outer peripheral side of the storage case 41. There is. As a result, the infusion tube 2 is less likely to be caught in the internal wiring 27 connecting the first ultrasonic sensor 21 and the measurement control device 90. Therefore, for example, the internal wiring 27 may be cut due to the infusion tube 2 being caught. Can be eliminated.

(5) In the present embodiment, since the measuring tube holder 42 and the flow rate measuring tube 11 are made of a transparent material, when the flow measuring tube 11 is stored in the measuring tube accommodating portion 43 of the measuring tube holder 42, the flow measuring tube 11 is stored. The state of the infusion solution W1 flowing in the flow rate measuring pipe 11 can be confirmed.

(6) In the present embodiment, the flow rate measuring tube 11 is provided in the middle of the infusion tube 2 through which the infusion solution W1 flows. Further, since the infusion tube 2 is thin (the outer diameter is about 3 mm), the flow rate measuring tube 11 connected to the infusion tube 2 can be formed thin. As a result, since a small sensor having a diameter of 10 mm can be used as the ultrasonic sensors 21 and 22 pressed against the flow rate measuring tube 11, the ultrasonic flow meter 20 can be compactly formed.

[Second Embodiment]
Hereinafter, a second embodiment embodying the present invention will be described with reference to the drawings. Here, the parts different from the first embodiment will be mainly described. In the present embodiment, the routing of the internal wiring connected to the first ultrasonic sensor 21 is different from that of the first embodiment.

More specifically, as shown in FIGS. 6 to 8, in the ultrasonic flow meter 100 of the present embodiment, two internal wirings (not shown) are connected to the ultrasonic vibrator of the first ultrasonic sensor 21. Both internal wirings are bound by a wiring tube 101. Further, a through hole 103a extending along the axial direction of the first sensor cover 103 is provided in the central portion of the first sensor cover 103 constituting the storage case 102.

The internal wiring connected to the first ultrasonic sensor 21 is bound to the wiring tube 101, and the through hole 59a of the first sensor fixing member 59 and the through hole of the first sensor cover 103. The 103a are inserted in order and pulled out to the outside of the ultrasonic flow meter 100. Then, the internal wiring connected to the first ultrasonic sensor 21 and drawn out to the outside of the ultrasonic flow meter 100 is connected to the measurement control device 90 (see FIG. 5).

Therefore, according to the present embodiment, the configuration of the holder-side contactor 72 and the cover-side contactor 82 of the first embodiment is not required, so that the component cost of the ultrasonic flowmeter 100 can be suppressed.

In addition, each of the above-mentioned embodiments may be changed as follows.

In the first embodiment, of the first sensor cover 51 and the second sensor cover 61, the first sensor cover 51, which is the sensor cover on the side where the spring unit 31 is not housed, is the measuring tube holder 42. It was attached so that it could be attached and detached. However, the second sensor cover 61, which is the sensor cover on the side where the spring unit 31 is housed, may be detachably attached to the measuring tube holder 42. Further, both the first sensor cover 51 and the second sensor cover 61 may be detachably attached to the measuring tube holder 42.

When the first sensor cover 51 is detachably attached to the measuring tube holder 42, the first end 42a of the measuring tube holder 42 when the first sensor cover 51 is separated from the measuring tube holder 42. The straight pipe storage portion 44 and the groove portions 45 and 46 open on the side. Then, when the first sensor cover 51 is connected to the measuring tube holder 42, the straight tube portion accommodating portion 44 and the groove portions 45, 46 are closed on the first end 42a side of the measuring tube holder 42. On the other hand, when the second sensor cover 61 is detachably attached to the measuring tube holder 42, the second sensor cover 61 of the measuring tube holder 42 is separated from the measuring tube holder 42 when the second sensor cover 61 is separated from the measuring tube holder 42. When the straight pipe storage part and the groove are opened on the end 42b side and the second sensor cover 61 is connected to the measuring pipe holder 42, the straight pipe storage part is on the second end 42b side of the measuring pipe holder 42. And the groove closes.

Further, in the first embodiment, the sensor cover (first sensor cover 51) that is detachably attached to the measuring tube holder 42 is a screw type cap that is connected to the measuring tube holder 42 by rotating. there were. However, the sensor cover that is detachably attached to the measuring tube holder 42 may be connected to the measuring tube holder 42 by using an adhesive or a screw, or may be the first end of the measuring tube holder 42. It may be fitted in the 42a or the second end 42b. Further, as shown in FIG. 9, the first sensor cover 171 may be a union screw type cap having a union nut 172. In this case, by rotating the union nut 172 and screwing it onto the measuring tube holder 173, the first sensor cover 171 is connected to the measuring tube holder 173. In this way, the first sensor cover 171 and the first sensor holder 174 fixed to the first sensor cover 171 do not rotate when connected to the measuring tube holder 173. As a result, the rubber sheet 176 covering the first ultrasonic sensor 175 held by the first sensor holder 174 is distorted, or the cover-side contactor 177 also held by the first sensor holder 174 is displaced. It is less likely that problems such as rubber will occur.

The flow rate measuring pipe 11 of each of the above embodiments has a shape (crank shape) in which the bent portion 15 on the upstream side and the bent portion 16 on the downstream side are bent at right angles in opposite directions via the straight pipe portion 14. However, it is not limited to this. Specifically, as shown in FIG. 10, in the flow rate measuring pipe 111, the bent portion 112 on the upstream side and the bent portion 113 on the downstream side are bent in the same direction (U-shape). May be good. Further, the flow rate measuring pipe may have a shape (Z-shape) in which the bent portion on the upstream side and the bent portion on the downstream side are bent at an acute angle in opposite directions via the straight pipe portion.

-Although the storage case 41 of each of the above embodiments has a cylindrical shape, it may have another cylindrical shape such as an elliptical cylinder or a rectangular cylinder. Further, the storage case may have a columnar shape such as a columnar shape or a square columnar shape. When the storage case has a columnar shape, the measuring tube storage portion is notched, for example, in the measuring tube holder.

-In each of the above embodiments, the measurement control device 90 is provided with a display device 94 that displays the flow rate of the infusion solution W1. However, a display device may be provided on the ultrasonic flowmeter, specifically, the first sensor cover constituting the ultrasonic flowmeter. Further, as shown in FIG. 11, the display device 122 may be provided on the second sensor cover 121 constituting the ultrasonic flow meter 120. Further, as shown in FIG. 12, the ultrasonic flow meter 130 may be attached to a drip stand (girdle stand) (not shown) via a clip 132 extending from the second sensor cover 131. A display device 133 is provided on the second sensor cover 131, and the flow measuring tube 134 housed in the ultrasonic flow meter 130 has a bent portion 135 on the upstream side and a bent portion 136 on the downstream side in the same direction. It has a curved shape (U-shape). Further, as shown in FIG. 13, even if the ultrasonic flow meter 140 is connected to the electrical component 142 having the display device 141 via the flexible cable 143 and the electrical component 142 is attached to the drip stand 144. good.

-In each of the above embodiments, a plurality of types of measuring tube holders different according to the shape and dimensions of the flow measuring tube are prepared in advance, and one measuring tube holder is prepared from among them according to the shape and dimensions of the flow measuring tube. The flow measuring tube may be replaced by selecting. Here, examples of the measuring tube holder include the measuring tube holder 42 used in each of the above embodiments, the measuring tube holders 151 and 161 shown in FIGS. 14 (a) and 14 (b), and the like. The measuring tube holder 151 houses a flow measuring tube 154 in which the bent portion 152 on the upstream side and the bent portion 153 on the downstream side are bent in the same direction (U-shape). Further, the measuring pipe holder 161 houses a flow rate measuring pipe 163 having a straight pipe portion 162 longer than the straight pipe portion 14 of each of the above embodiments. Then, both the first sensor cover 51 and the second sensor cover 61 are detachably attached to the selected measuring tube holder.

The method of replacing the flow measuring tube will be described below. First, after removing the first sensor cover 51 and the second sensor cover 61, the flow rate measuring tube 11 is taken out from the measuring tube holder 42. Next, a preparation selection step is performed, and one measuring tube holder is selected from the three types of measuring tube holders 42, 151, 161 prepared in advance. In the subsequent assembly step, the flow rate measuring tube corresponding to the measuring tube holder is stored in the selected measuring tube holder with the infusion tube 2 connected, and the first sensor cover 51 and the second sensor cover 61 are attached. Connect. At this point, the replacement of the flow measuring tube is completed. After that, the flow rate is measured in the measurement process.

In this case, when the flow rate measuring tube 11 is replaced, only the measuring tube holder 42 (and the flow measuring tube 11) is replaced, and the first sensor cover 51 and the second sensor cover 61 can be used as they are, so that they can be stored. As compared with the case where the entire case 41 is replaced, the component cost can be reduced. Incidentally, in the ultrasonic flowmeter described in Patent Document 1, when trying to attach a flow measuring tube having a different shape and dimensions to a holder, it is necessary to change the design of the holder according to the direction in which the inflow port and the outflow port are opened. Therefore, the mounting portion of the flow measuring tube cannot be used as it is. In this case, there is a problem that the component cost becomes high.

-The ultrasonic flow meters 20 and 100 of each of the above embodiments are adapted to measure the flow rate of the infusion solution W1 flowing through the flow rate measuring tube 11 by using ultrasonic sensors 21 and 22. However, the ultrasonic flow meters 20 and 100 may further have a function of detecting air bubbles mixed in the infusion solution W1 in addition to the function of detecting the flow rate of the infusion solution W1. More specifically, when air bubbles are mixed in the infusion solution W1, the sensitivity of the ultrasonic wave reception signal received by the ultrasonic sensors 21 and 22 decreases. Therefore, the measurement control device 90 detects bubbles mixed in the infusion solution W1 based on the decrease in the sensitivity of the received signal. By doing so, the installation space of the ultrasonic sensor can be reduced as compared with the case where the ultrasonic sensor is separately provided for the flow rate measurement and the bubble detection, and the ultrasonic flow meters 20 and 100 can be miniaturized. It will be possible. Further, since the circuit parts such as the signal processing unit 91 and the arithmetic processing unit 92 can be shared, the cost of parts of the measurement control device 90 can be suppressed.

-The ultrasonic flow meters 20 and 100 of each of the above embodiments are adapted to measure the flow rate of the infusion solution W1 flowing through the flow rate measuring tube 11 by using ultrasonic sensors 21 and 22. However, the ultrasonic flowmeters 20,100 may further have a function of measuring the concentration of the infusion solution W1 in addition to the function of detecting the flow rate of the infusion solution W1. By doing so, the installation space of the ultrasonic sensor can be reduced as compared with the case where the ultrasonic sensor is separately provided for the flow rate measurement and the concentration measurement, and the ultrasonic flow meters 20 and 100 can be downsized. It will be possible. Further, since the circuit parts such as the signal processing unit 91 and the arithmetic processing unit 92 can be shared, the cost of parts of the measurement control device 90 can be suppressed.

-In each of the above embodiments, the ultrasonic flow meter 20 was installed at a position between the infusion bag 3 and the pump device 7 in the infusion tube 2, but between the pump device 7 and the clamp 6 in the infusion tube 2. The ultrasonic flow meter 20 may be installed at the position of.

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

(1) In any one of claims 1 to 10, the bent portions on the upstream side and the downstream side of the flow measuring pipe are bent in the same direction or opposite directions to each other. Ultrasonic flow meter.

(2) In any one of claims 1 to 10, the ultrasonic flow meter has a function of detecting bubbles mixed in the liquid based on an ultrasonic reception signal received by the ultrasonic sensor. An ultrasonic flow meter characterized by further having.

(3) The ultrasonic flowmeter according to any one of claims 1 to 10, further comprising a function of measuring the concentration of the liquid.

(4) The infusion tube through which the infusion solution which is a liquid flows has flexibility, an infusion bag is connected to the base end, and an adjustment knob is installed in the middle of the infusion tube, and the infusion bag in the infusion tube. A liquid feeding means for delivering the infusion solution in the infusion bag toward the tip of the infusion tube is installed at a position between the infusion bag and the adjustment knob, and the infusion bag and the liquid feeding means in the infusion tube are provided. The ultrasonic flow meter according to any one of claims 1 to 10 is installed at a position between the infusion tubes or between the liquid feeding means and the adjusting knob in the infusion tube. Infusion system.

2 ... Infusion tube as a tube 11,111,134,154,163 ... Flow measurement tube 12 ... Inflow port 13 ... Outlet 14,162 ... Straight tube portion 15,16,112,113,135,136,152,153 ... Bending portions 20, 100, 120, 130, 140 ... Ultrasonic flow meters 21,175 ... First ultrasonic sensor 22 as an ultrasonic sensor 22 ... Second ultrasonic sensor 31 as an ultrasonic sensor ... Biasing member Spring units 41, 102 ... Storage cases 42, 151, 161, 173 ... Measuring tube holder 42a ... First end 42b ... Second end 42c ... Outer peripheral surface 43 as peripheral surface ... Measuring tube storage part 44 ... Straight pipe part Storage portions 45, 46 ... Grooves 51, 103, 171 ... First sensor covers 61, 121, 131 ... Second sensor covers 72 ... Holder side contacts 82, 177 ... Cover side contacts 122, 133, 141 ... Display Device W1 ... Infusion as a liquid

Claims (8)

It is arranged in the middle of the pipe through which the liquid flows and has bent portions bent at right angles to both ends, and is arranged opposite to the upstream position and the downstream side position, and the ultrasonic waves are alternately propagated through the flow measurement pipe. A pair of ultrasonic sensors and
An urging member that applies an urging force for pressing the ultrasonic sensor against the bent portions on the upstream side and the downstream side of the flow measuring pipe, and
The liquid is provided with the flow measuring tube, the pair of ultrasonic sensors, and a storage case for accommodating the urging member, and is based on the difference in propagation time of ultrasonic waves transmitted and received between the pair of ultrasonic sensors. An ultrasonic flow meter that measures flow rates.
The storage case includes a measuring tube holder having a measuring tube storage portion, and a first sensor cover that houses the ultrasonic sensor on the upstream side and is connected to a first end of the measuring tube holder in the longitudinal direction. A second sensor cover that houses the ultrasonic sensor on the downstream side and is connected to the second end of the measuring tube holder in the length direction is included.
The measuring pipe accommodating portion covers the periphery of the flow measuring pipe and exposes the end portion of the flow measuring pipe on the inflow port side and the end portion on the outflow port side to the peripheral surface of the measuring pipe holder.
An ultrasonic wave characterized in that the sensor cover on the side of the first sensor cover and the second sensor cover on which the urging member is not housed is detachably attached to the measuring tube holder. Flowmeter. The flow rate measuring pipe has a straight pipe portion extending straight and has bent portions at both ends of the straight pipe portion.
The measuring tube accommodating portion has a straight pipe accommodating portion for accommodating the straight pipe portion and a groove portion communicating with the straight pipe accommodating portion and opening on the peripheral surface of the measuring tube holder.
When the sensor cover detachably attached to the measuring tube holder among the first sensor cover and the second sensor cover is separated from the measuring tube holder, the first end of the measuring tube holder. The straight pipe storage portion opens on the side or the second end side,
According to claim 1, when the sensor cover is connected to the measuring tube holder, the straight tube portion accommodating portion closes on the first end side or the second end side of the measuring tube holder. The ultrasonic flowmeter described. The ultrasonic flowmeter according to claim 2, wherein the width of the groove portion is smaller than the inner diameter of the straight pipe portion accommodating portion. The measuring tube holder has a holder-side contact and
Of the first sensor cover and the second sensor cover, the sensor cover that is detachably attached to the measuring tube holder has a cover-side contactor.
Any one of claims 1 to 3, wherein the holder-side contactor and the cover-side contactor are arranged so as to face each other so as to come into contact with each other when the sensor cover is connected to the measuring tube holder. The ultrasonic flowmeter described in the section. The ultrasonic flowmeter according to any one of claims 1 to 4 , wherein the measuring tube holder is made of a transparent material. Of the first sensor cover and the second sensor cover, the sensor cover that is detachably attached to the measuring tube holder is a screw type cap that is connected to the measuring tube holder by rotating. The ultrasonic flow meter according to any one of claims 1 to 5 , wherein the ultrasonic flow meter is characterized. The ultrasonic flow rate according to any one of claims 1 to 6 , wherein the first sensor cover or the second sensor cover is provided with a display device for displaying the flow rate of the liquid. Total. The ultrasonic flow meter according to any one of claims 1 to 7 , wherein the flow rate measuring tube is provided in the middle of an infusion tube for flowing an infusion solution which is a liquid.

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