JP6478815B2 - Peristaltic infusion pump - Google Patents

Description

  The present invention relates to a peristaltic infusion pump that forcibly sends liquid by imparting peristaltic motion to an infusion tube.

  In the medical field, when an infusion agent such as a blood component or a medicinal solution is sent to the human body (patient's body) by an infusion line, an infusion pump is used to accurately deliver a certain amount. Examples of the infusion pump include those employing a peristaltic type (peristaltic finger method).

  The peristaltic infusion pump applies a peristaltic motion from the upstream side to the downstream side of the infusion tube by pressing a plurality of pressure-contacting fingers on one side of the flexible infusion tube and advancing and retreating each pressure-contacting finger in sequence. To do. Each press-contact finger presses against the other side of the infusion tube by advancing toward a pressing plate that presses one side of the infusion tube.

  Each pressure contact finger is arranged adjacently along the infusion tube, and is advanced and retracted by a plurality of cams. Each cam is inserted through a camshaft connected to a rotation driving means such as a motor, and is fixed to the camshaft by being displaced by a predetermined angle in the rotation direction of the camshaft.

  The cams are sequentially advanced by the rotation of the camshaft, and the press-finger fingers are sequentially advanced and retracted from the upstream side to the downstream side as the cams rotate. Thereby, a peristaltic motion is given to the infusion tube abutted on each pressure contact finger.

  By the way, this type of peristaltic infusion pump is provided with a clogging detector for detecting clogging of the infusion line and a bubble detector for detecting bubbles mixed in the infusion tube (see, for example, Patent Document 1). ).

  The occlusion detector includes a pressure sensor that detects the internal pressure of the infusion tube. For example, when the injection needle at the end of the infusion line is clogged with a thrombus or bent (kink) in the middle of the infusion line, the flow of the infusion is hindered, and the infusate that has lost its place increases the pressure in the infusion line. By detecting this increase in pressure with a pressure sensor, a blockage of the infusion line is detected.

  On the other hand, the bubble detector generally uses an ultrasonic sensor, and detects that air has been mixed into the infusion line by utilizing the fact that the attenuation rate of ultrasonic waves differs greatly between air and water.

Japanese Utility Model Publication No. 1-170248

  The occlusion detector and the bubble detector are different in detection object and detection method. For this reason, in the conventional infusion pumps, both the blockage detector and the bubble detector are built in the infusion pump. However, two expensive detectors are required, and the two detectors must be accommodated in the casing of the infusion pump, resulting in a disadvantage that the infusion pump becomes large.

  Moreover, the bubble detector which employ | adopted the ultrasonic sensor needs to contact | adhere the detection surface (ultrasonic wave generation surface) and infusion tube of a bubble detector. However, if foreign matter such as dust enters between the detection surface of the bubble detector and the infusion tube, or if a gap is generated between the detection surface of the bubble detector and the infusion tube, the mixture of bubbles in the infusion tube is erroneously detected. There is a fear.

  In addition, according to the bubble detector that employs an ultrasonic sensor, accurate bubble detection may not be possible due to the influence of the material of the infusion tube. That is, if the infusion tube is too hard, the infusion tube cannot be deformed following the shape of the detection surface of the bubble detector, and a gap is generated between the detection surface and the infusion tube, and there is a risk of erroneous detection of bubbles. On the other hand, if the infusion tube is too soft, the restoring force of the infusion tube is small, so that the pressure for pressing the infusion tube against the detection surface is insufficient, and a gap is generated, which may erroneously detect air bubbles. Furthermore, in an infusion tube made of soft vinyl chloride, adhesion (self-fusion) between the infusion tubes in an unused storage state is prevented by providing fine irregularities (embosses) on the surface. In addition, the fine irregularities on the surface of the infusion tube may hinder the close contact with the detection surface, and there is a possibility that air bubbles are erroneously detected.

  In view of the above points, an object of the present invention is to provide an infusion pump that can accurately detect the mixing of bubbles into an infusion tube without using an ultrasonic sensor.

[1] In order to achieve the above object, the present invention provides:
A peristaltic infusion pump for connecting a medical container containing a liquid and a human body and forcibly flowing the liquid flowing in a flexible infusion tube by peristally moving the infusion tube. ,
A plurality of closing points for preventing the flow of the liquid in the infusion tube, and one closing point formed with the progress of a peristaltic movement for liquid feeding and another closing point; Volume changing means for changing the volume of the closed region sandwiched between;
Pressure detecting means for detecting the pressure in the infusion tube in the closed region;
Bubble detection means for determining the presence or absence of air mixed in the infusion tube based on a change in the amount of change in pressure of the infusion tube detected by the pressure detection means by adding a volume change by the volume change means ; It is characterized by providing.

  According to the peristaltic infusion pump of the present invention, it is possible to accurately detect the mixing of bubbles into the infusion tube with a simple configuration using the volume changing means and the pressure detecting means without using an ultrasonic sensor.

  [2] In the present invention, the pressure when the upstream side of the pressure detection means is closed and the downstream side of the pressure detection means is released (hereinafter referred to as downstream pressure), and the downstream side of the pressure detection means are closed. The pressure detection means detects the pressure when the upstream side of the pressure detection means is released (hereinafter referred to as upstream pressure), and detects the blockage of the infusion tube based on the downstream pressure and the upstream pressure. It is preferable to provide a blockage detection means.

  According to the present invention, it is possible to detect a bubble by the bubble detection unit and to detect a blockage by the blockage detection unit by using one pressure detection unit. Therefore, it is possible to detect the blockage of the infusion line and the mixing of bubbles into the infusion tube with a simple configuration without using a plurality of sensors.

[3] Further, in the present invention, a finger pump type having a plurality of press-contacting fingers that can crush the infusion tube, and a plurality of press-fitting fingers that are displaced by a predetermined angle, each moving forward and backward. , A camshaft that supports a plurality of cams, and a drive source that rotates the camshaft, and is the minimum required to continue crushing the infusion tube at one or more locations during one rotation of the camshaft By defining the number of pressure welding fingers as “normal number” and installing more pressure fingers than the normal number required, the ratio of the closed area to the pump cycle is the normal number of pressure fingers. It is preferable to expand than when installing .

  Here, the normal number will be described. First, in the case where each pressure contact finger is pressed by a plurality of cams that are displaced from the camshaft by a predetermined angle, the infusion tube is crushed at one or more locations during one rotation of the camshaft. Therefore, it is necessary to prepare the cam and the pressure contact finger at least for the camshaft making one turn. For example, if the predetermined angle is 30 °, twelve cams and pressure contact fingers are required at a minimum in order to continue crushing the infusion tube at one or more locations during one rotation of the camshaft. Therefore, the normal number in the present specification is defined as the minimum number of pressure-contacting fingers necessary for continuing to crush the infusion tube at one or more locations during one rotation of the camshaft.

  As described above, by extending the ratio of the closed region in the pump cycle, it is possible to secure a long time for measuring the pressure. For example, the detection value is subjected to low-pass filter processing or a plurality of detections. The values can be averaged, and can be made less susceptible to noise.

[4] In the present invention, it is preferably configured to impart a volume change in the closed region by profiled cam integrally assembled to the camshaft of the full Ingaponpu.

  According to such a configuration, a separate drive source for applying a volume change in the closed region is not required, and a volume change can be applied in the closed region using the drive source that rotates the camshaft.

[ 5 ] Further, in the present invention, the peristaltic infusion pump is composed of a roller peristaltic infusion pump, the stator is divided, pressure detecting means is installed between the stators, and the infusion tube is not handled (playing). It is also possible to provide a change in volume in the closed region by pressing and pressing the movable piece using a single roller.

[ 6 ] Further, in the present invention, the volume changing means may be configured to apply a volume change to the infusion tube by applying an external force to the infusion tube.

[ 7 ] Further, in the present invention, a finger pump type having a plurality of press-contacting fingers capable of squeezing the infusion tube, a plurality of cams for moving the plurality of press-contacting fingers forward and backward, and a plurality of cams being pivotally supported. A camshaft that rotates, a drive source that rotates the camshaft , and angle detection means that detects a rotation angle of the camshaft , and the volume changing means is configured to detect the rotation angle of the camshaft based on the angle detected by the angle detection means. It is also possible to synchronize the action of an external force with the detection of pressure by the pressure detection means.

[ 8 ] Further, in the present invention, the pressure detection means may use a load sensor that detects a force with which the infusion tube tends to expand due to the pressure inside the infusion tube.

[ 9 ] In the present invention, when a load sensor is used as the pressure detecting means, a high detection speed can be obtained by adopting a semiconductor strain gauge bridge formed on one chip.

[ 10 ] In the present invention, the sensor moving means for separating the load sensor from the infusion tube, the storage means for storing the output of the load sensor when the load sensor is separated from the infusion tube, and the infusion tube It is preferable to include a correction unit that corrects the detected value based on the output of the load sensor stored in the storage unit. According to this, the detection accuracy of the load sensor can be improved.

[ 11 ] Further, in the present invention, the position for determining the quality of the height position relative to the medical container and the human body based on the pressure detected by the pressure detecting means when each pressure contact finger is in pressure contact with the infusion tube. A relationship determination means can also be provided. According to this, the positional relationship determining means can be performed using the pressure detecting means used for detecting the bubbles by the bubble detecting means. Therefore, it is possible to determine the quality of the height position with respect to the medical container and the human body without adding a sensor, and it is possible to obtain a highly reliable small peristaltic infusion pump.

The block diagram which shows typically the principal part of the peristaltic infusion pump of 1st Embodiment. The figure which shows the shape of a press-contact finger and a cam. FIG. 3A to FIG. 3D are diagrams showing a liquid feeding operation by a pump mechanism. FIG. 4A is a diagram showing a state in which the infusion tube is crushed. FIG. 4B is a diagram showing a fourth pressure contact finger. FIG. 4C is a diagram showing another fourth pressure-contact finger. 5A to 5D are views showing pressures detected by a load sensor. 6A to 6D are diagrams showing pressure detected by a load sensor. 7A and 7B are diagrams showing an outline of sensor moving means. The figure which shows the tube holding structure by a sensor. The figure which shows the cross-sectional shape of the state by which the infusion tube was crushed. The figure which shows the peristaltic rocking | fluctuation pump of 2nd Embodiment. The figure which shows a deformed cam. The upper stage of FIG. 12 is a diagram showing a transition of a state in which each pressure contact finger closes the infusion tube according to the rotation angle of the camshaft. The lower part of FIG. 12 is a diagram showing the output value of the load sensor 14 detected according to the rotation angle of the camshaft 5. The figure which shows the peristaltic rocking | fluctuation pump of 3rd Embodiment. The figure which shows the state which the movable part 39 opened. The figure which shows the state with which the infusion tube 1 was mounted | worn with the roller type peristaltic infusion pump. The figure which shows a state when the rotation angle of a rotor is 0 degree. The figure which shows a state when the rotation angle of a rotor is 12 degrees. The figure which shows a state when the rotation angle of a rotor is 30 degrees. The figure which shows a state when the rotation angle of a rotor is 48 degrees. The figure which shows a state when the rotation angle of a rotor is 60 degrees. 21A to 21D are diagrams showing the relationship between the rotation angle of the rotor and the waveform of the output signal of the load sensor. FIG. 21A is a diagram showing a waveform in a normal state. FIG. 21B is a diagram showing a waveform when the position of the container is low. FIG. 21C is a diagram showing a waveform when the position of the patient is high. FIG. 21D is a diagram illustrating a waveform in the case of liquid feeding in the reverse direction or an abnormal positional relationship between the medical container and the human body. FIG. 22A is a diagram showing a waveform of an output signal of the load sensor in the downstream closed state. FIG. 22B is a diagram showing a waveform of an output signal of the load sensor in the upstream closed state. FIG. 22C is a diagram showing a waveform of an output signal of the load sensor when the infusion tube is empty. FIG. 22D is a diagram showing a waveform of an output signal of the load sensor when air bubbles are mixed.

[First Embodiment]
An embodiment of the present invention will be described with reference to the drawings. The peristaltic infusion pump of this embodiment is used when a body fluid, a blood component, or a liquid such as a chemical solution is sent to the human body in the medical field, and a medical container (infusion solution container) that stores a liquid such as a chemical solution. This is a device for forcibly sending the liquid in the infusion tube 1 in the downstream direction by applying a peristaltic motion to the infusion tube 1 having flexibility provided in the infusion line connecting the body and the human body.

  As schematically shown in FIG. 1, the peristaltic infusion pump of the present embodiment includes a press plate 2 (press portion) that contacts one side of the infusion tube 1, and the infusion tube 1 facing the press plate 2. A pump mechanism 3 that abuts on the other side and a control means 4 comprising a microcomputer are provided.

  The holding plate 2 is a hard thick plate formed of metal, synthetic resin, or the like, and a flat surface 2a on one side is in contact with the infusion tube 1. The holding plate 2 is urged in a direction in contact with the infusion tube 1 by a spring 2b (biasing means).

  The pump mechanism 3 includes twelve pressure-contact fingers f1 to f12 opposed to the flat surface 2a of the pressing plate 2 via the infusion tube 1, and twelve cams m1 to m12 that advance and retract the pressure-contact fingers f1 to f12 in the horizontal direction. A rotatable camshaft 5 that supports each of the cams m1 to m12, a drive motor 6 (drive source) that rotationally drives the camshaft 5, a rear end of the fourth pressure contact finger f4, and a fourth An actuator 18 (see FIG. 4) that can press the pressure contact finger f4 toward the infusion tube 1 is provided.

  The pressure fingers f1 to f12 are arranged adjacent to each other in the vertical direction corresponding to the upstream side to the downstream side of the infusion tube 1. The first pressure contact finger f1 is located on the most upstream side, and the twelfth pressure contact finger f12 is located on the most downstream side.

  As shown in FIG. 2, the pressure fingers f <b> 1 to f <b> 12 include a pressure contact portion 7 that presses against the infusion tube 1 at the tip. Each press-contact finger f1-f12 is provided with the cam engaging part 8 engaged with the cams m1-m12 on the rear end side.

  Each of the cams m1 to m12 is formed in a substantially disk shape, and is arranged adjacent to each other in the vertical direction corresponding to the arrangement of the press contact fingers f1 to f12. A camshaft 5 is fixed to each cam m1 to m12 at an eccentric position. Each of the cams m1 to m12 includes a pressing surface 9 in which a part of the outer peripheral surface protrudes substantially in the radial direction by being eccentrically supported by the camshaft 5. In other words, the portion of each of the cams m1 to m12 that protrudes in the eccentric direction relative to the camshaft 5 is a portion that includes the pressing surface 9.

  As shown in FIG. 1, the camshaft 5 is provided with a driven pulley 10 on one end side, and a belt 13 is driven from a drive pulley 12 provided on the upper end side of a drive shaft 11 extending from the drive motor 6. Rotation is transmitted through.

  As the camshaft 5 rotates and the cams m1 to m12 rotate within the cam engaging portion 8 of the press contact fingers f1 to f12, the press contact fingers f1 to f12 sequentially advance and retreat as shown in FIGS. 3A to 3D. Then, the infusion tube 1 is crushed and released between the presser plate 2. At this time, a peristaltic motion is imparted to the infusion tube 1 interposed between the pressure contact fingers f1 to f12 and the presser plate 2, and the infusion agent in the infusion tube 1 is sent from upstream to downstream.

  The rotation angle of the camshaft 5 is detected by angle detection means. As the angle detection means, an encoder or a stepping motor is adopted as the drive motor 6. When a stepping motor is employed as the drive motor 6, the angle of the camshaft 5 can be known from the number of steps of the drive motor 6. And the advance / retreat position of each press-contact finger f1-f12 can be confirmed by counting the number of steps of the drive motor 6. FIG.

  A load sensor 14 (pressure detection means) is disposed between the sixth pressure contact finger f6 and the seventh pressure contact finger f7. The load sensor 14 employed in the present embodiment is a sensor for detecting the magnitude of a dynamic action such as a force sensor or a load cell.

  Here, the load sensor 14 employed in the present embodiment will be described. In the rotation of the camshaft 5 using the twelve pressure contact fingers f1 to f12, the pressure of the infusion tube 1 is detected while passing through a range within an angle of at least 5 degrees. In this case, high detection accuracy for the angle is required, and when the operation cycle of the pressure fingers f1 to f12 is fast, a response speed capable of detecting pressure at high speed is required.

  Specifically, when operating at a maximum flow rate of 999 mL / h, the liquid feeding operation is repeated at a rate of about 2 cycles per second. Since the time for passing through the range of 5 degrees out of 360 degrees per rotation is 1 ÷ 2 × 5 ÷ 360 = 0.00694 s (6.94 ms), the response time of the load sensor 14 is within about 7 ms at the latest, During this time, accurate pressure detection is required. For this reason, it is preferable to employ a sensor using a strain gauge, a pressure-sensitive element using pressure-sensitive conductive rubber, or the like as the load sensor 14.

  As a particularly suitable load sensor 14, among sensors employing a strain gauge, a sensor having a very small silicon diaphragm structure formed with a semiconductor strain gauge bridge manufactured by a photoetching method, which is a manufacturing process similar to an integrated circuit ( Force sensor). Even if the load applied to the sensor changes, the deformation of the diaphragm is minimal, so that the volume change necessary for transmitting the load is relatively minimal. As a result, a high detection response speed can be obtained.

  The control means 4 is composed of an electronic unit composed of a CPU, a memory, and the like, and controls the drive motor 6 (drive source) by executing a control program held in a storage device such as a memory by the CPU. The control unit 4 includes a blockage detection unit that detects blockage of the infusion line, a bubble detection unit that detects mixing of bubbles in the infusion tube 1, and a positional relationship determination unit that determines whether the height position of the medical container and the human body is good or bad. Is functionally equipped.

  As will be described later, the control means 4 having these functions performs blockage detection, bubble detection, and positional relationship determination using the output from the load sensor 14. In addition, the control means 4 drives a notifying means such as an alarm (not shown) to notify the user of an abnormality when it is determined to be abnormal by the blockage detection, the bubble detection, and the positional relationship determination. Stop liquid feeding by 3.

  In the closed state of the infusion line, the restoring force of the infusion tube 1 crushed to some extent is detected by the load sensor 14. When any of the second pressure finger f2 to the fifth pressure finger f5 is crushing the infusion tube 1 (see FIG. 3B), if the downstream side of the load sensor 14 is blocked in the infusion line and the pressure increases, the infusion tube 1 The restoring force of the infusion tube 1 applied to the load sensor 14 due to the increase in the pressure inside increases. In proportion to this, the electrical output of the load sensor 14 also increases, and it is detected by the function of the blockage detection means of the control means 4 that the blockage has occurred on the downstream side of the load sensor 14.

  On the other hand, when any of the eighth pressure finger f8 to the eleventh pressure finger f11 is crushing the infusion tube 1 (see FIG. 3D), if the upstream side of the infusion line is blocked and the pressure in the infusion line decreases, the infusion The restoring force of the infusion tube 1 applied to the load sensor 14 due to the pressure drop in the tube 1 decreases. In proportion to this, the electrical output of the load sensor 14 also decreases, and it is detected by the function of the blockage detection means of the control means 4 that the blockage has occurred on the upstream side of the load sensor 14.

  In the present embodiment, the closed region is formed by using the first pressure finger f1 and the twelfth pressure finger f12 (closing means). That is, the first pressure contact finger f1 (upstream pressure contact finger) and the twelfth pressure contact finger f12 (downstream pressure contact finger) are fed by the operation of the first cam m1 (upstream cam) and the twelfth cam m12 (downstream cam), respectively. , The infusion tube 1 is simultaneously crushed on the upstream side and the downstream side of the load sensor 14 during one cycle operation (while one advance / retreat operation is completed for all the pressure fingers f1 to f12).

  At this time, as shown in FIG. 4A, the actuator 18 is operated so that the fourth pressure finger f4 pushes the infusion tube 1 to change the volume in the infusion tube 1. In the present embodiment, the fourth pressure finger f4 and the actuator 18 correspond to volume changing means.

  As shown in FIG. 4B, at the rear end of the fourth pressure contact finger f4, a swinging portion f4a that is swingably connected, and the swinging portion f4a toward the fourth pressure contact finger f4 side in the swinging direction. An urging torsion spring f4b is provided. The swing part f4a does not normally swing by the urging force of the torsion spring f4b. The fourth pressure finger f4 moves forward and backward by the rotation of the fourth cam m4.

  When the fourth pressure contact finger f4 is pressed by the actuator 18, as shown in FIG. 4B, the swinging part f4a swings toward the rear of the fourth pressure contact finger f4, and the swinging part f4a becomes the fourth cam. The forward movement of the fourth pressure contact finger f4 is not prevented by being caught by m4.

  Note that the fourth pressure contact finger of the present invention is not limited to that shown in FIG. 4B. For example, as shown in FIG. 4C, the swinging portion f4a ′ indicated by hatching by two-color molding is used in addition to the fourth pressure contact finger. It is also possible to mold the material softer than the material of this part, so that the swing part f4a ′ operates in the same manner as the swing part f4a shown in FIG. 4B.

  A pressure change occurs inside the infusion tube 1 by the pressing of the fourth pressure contact finger f4 to the infusion tube 1 by the actuator 18 serving as a volume changing means. This pressure change is detected by the load sensor 14. That is, if the pressure rise is large, it can be seen that the inside of the closed region is filled with an incompressible fluid (that is, a liquid such as an infusion solution). Conversely, if the pressure rise is small, it can be seen that a compressive fluid (that is, air) is mixed in the infusion tube 1.

  In the liquid feeding operation, not only the infusion tube 1 is crushed sequentially from the first pressure contact finger f1 on the upstream side, but also after the crushing to the twelfth pressure contact finger f12 is completed, it is released and again sequentially from the first pressure contact finger f1. The crushing operation is repeated.

  Then, when the twelfth press contact finger f12 is separated from the infusion tube 1 and the first press contact finger f1 is pressed against the infusion tube, the first press contact finger f1 is not in the infusion tube so as not to cause rapid liquid supply due to a free flow state. 1 is crushed and then the twelfth press contact finger f12 is operated in the order of separating from the infusion tube 1. Thus, the infusion tube 1 is simultaneously closed at two locations on the upstream side and the downstream side of the load sensor 14 while the liquid feeding operation is performed for one cycle (see FIG. 3A).

  The amount of liquid that can be supplied during one cycle of the liquid supply operation is the amount of liquid present in the infusion tube 1 at the moment when the infusion tube 1 is closed at two locations, the first pressure contact finger f1 and the twelfth pressure contact finger f12. Fewer. According to the peristaltic infusion pump of this embodiment, the bubble passage can be prevented by performing the bubble detection operation once per cycle.

  The presser plate 2 includes a flat surface 2 a as a tube pressure contact surface that contacts the infusion tube 1. An elastic member is provided on the flat surface 2a.

  In this embodiment, the load sensor 14 as a pressure detection means is installed between the sixth pressure contact finger f6 and the seventh pressure contact finger f7. The portion of the infusion tube 1 located at the portion where the load sensor 14 is arranged moves the infusion tube 1 due to a pressure change caused by the advance / retreat of the pressure fingers f1 to f12 or a change in the volume in the infusion tube 1, or the infusion tube 1 As shown in FIG. 8, it is fitted in the groove of the load sensor 14 and crushed so that the cross-sectional shape becomes an oval (ellipse).

  By crushing the infusion tube 1 in this way, the restoring force of the infusion tube 1 acts on the load sensor 14 to push up the electrical signal output from the load sensor 14 to the plus side, so the upstream side of the infusion tube 1 is blocked. Even if the pressure in the infusion tube 1 decreases, the load sensor 14 can appropriately detect a decrease in the internal pressure of the infusion tube 1.

  Also, in order to reliably detect bubbles, holding the portion of the infusion tube 1 corresponding to the position of the load sensor 14 with the holding mechanism securely detects a minute volume change in the infusion tube 1. Is necessary for.

  Cams m1 to m12 assembled to the camshaft 5 have a perfect circular shape. The cams m1 to m12 are provided corresponding to the press contact fingers f1 to f12, and are assembled to the camshaft 5 while being shifted by a certain angle (30 degrees when there are 12 press contact fingers).

  Next, refer to FIGS. 5 and 6 for the output signal (voltage) and pressure from the load sensor 14 when the volume change in the infusion tube 1 generated by the liquid feeding operation is used, and the determination of each abnormality caused thereby. To explain. 5 and 6, the time order elapses from left to right. The numbers in the lower part of the figure indicate the numbers of the pressure fingers that crush the infusion tube 1.

  Section A is a section in which the first press contact finger f1 and the twelfth press contact finger f12 close the top and bottom of the load sensor 14 (see FIG. 3A). The waveform of the output signal of the load sensor 14 obtained in this section corresponds to the pressure accompanying the volume change in the closed region.

  The section B is a section in which any of the first pressure finger f1 to the sixth pressure finger f6 is crushing the infusion tube 1 (see FIG. 3B). The waveform of the output signal of the load sensor 14 obtained in this section corresponds to the pressure on the downstream side of the load sensor 14.

  The section C is a section in which the sixth press contact finger f6 and the seventh press contact finger f7 close the top and bottom immediately adjacent to the load sensor 14 (see FIG. 3C). The waveform of the output signal of the load sensor 14 obtained in this section corresponds to the pressure accompanying the volume change with a very small internal volume.

  The section D is a section in which any of the seventh pressure finger f7 to the twelfth pressure finger f12 is crushing the infusion tube 1 (see FIG. 3D). The waveform of the output signal of the load sensor 14 obtained in this section corresponds to the pressure on the upstream side of the load sensor 14.

  The output signals of the load sensor 14 shown in these waveforms are input to the control means 4, and pass / fail is determined by the functions of the blockage detection means, the bubble detection means, and the positional relationship determination means.

  The waveform shown in FIG. 5A indicates that the infusion is normally performed. In the present embodiment, the drop from the medical container to the human body via the infusion tube 1 is set to 1.2 m, and the peristaltic infusion pump of the present embodiment is installed at an intermediate height position. Yes.

  The main component of the infusion liquid filled in the infusion line of the embodiment is almost water, and the specific gravity is almost the same as that of water. Since the drop from the peristaltic infusion pump to the human body is 0.6 m, the water column pressure corresponds to -6 kPa. Since the human body is at a lower position than the peristaltic infusion pump, the pressure on the downstream side is negative if it is normal, and the output signal in section B also shows a negative value. The drop from the peristaltic infusion pump to the medical container is 0.6 m, and the water column pressure corresponds to +6 kPa.

  Since the medical container is located higher than the peristaltic infusion pump, the pressure on the upstream side is positive if it is normal, and the output signal in the section D also shows a positive value. In section C, since the internal volume is extremely small, in the normal infusion state (the state in which no bubbles are mixed), a change is applied in the decreasing direction to the small volume portion filled with the infusion agent, so the detected pressure And the output signal in the normal section C shows an extremely large value.

  In the section A, since the inner volume is equivalent to one cycle of the liquid feeding operation, the amount of change in the volume is smaller than that in the section C, but a signal indicating a relatively large pressure increase is obtained when it is normal.

  The waveform shown in FIG. 5B indicates that the medical container and the peristaltic infusion pump are at the same height. Compared with the waveform when normal infusion shown in FIG. 5A is performed, the output signal (pressure) in section D is almost zero. Since the pressure is almost zero upstream from the load sensor 14, it can be seen that the medical container and the peristaltic infusion pump are at the same height.

  The waveform shown in FIG. 5C indicates that the human body (patient) and the peristaltic infusion pump are at the same height. Compared with the waveform when normal infusion shown in FIG. 5A is performed, the output signal (pressure) in section B is almost zero. Since the pressure is almost zero downstream of the load sensor 14, it can be seen that the human body (patient) and the peristaltic infusion pump are at the same height.

  The waveform shown in FIG. 5D shows the abnormality in the positional relationship between the liquid feeding or medical container and the human body in the reverse direction. This waveform is completely opposite to the waveform when normal infusion shown in FIG. 5A is performed. In this case, the drive motor 6 is reversed, the mounting direction of the infusion tube 1 is upside down, or the position becomes higher in the order of medical container-peristaltic infusion pump-human body (patient). An abnormality such as When the control unit 4 determines that an abnormality is caused by such a waveform, the control unit 4 stops the pump mechanism 3 and notifies the abnormality.

  The waveform shown in FIG. 6A indicates that the infusion line on the downstream side of the load sensor 14 is blocked. Compared with the waveform when normal infusion shown in FIG. 5A is performed, the output signal of section B is extremely high. This indicates that the pressure has increased because the infusion agent does not flow smoothly downstream from the peristaltic infusion pump, and it can be determined that the infusion line downstream of the load sensor 14 is clogged. . The control means 4 determines that the downstream blockage is caused by such a waveform, stops the pump mechanism 3 and notifies the abnormality.

  The waveform shown in FIG. 6B indicates that the infusion line on the upstream side of the load sensor 14 is blocked. Compared with the waveform when normal infusion shown in FIG. 5A is performed, the output signal of section D is extremely low. This indicates that the inside of the infusion tube 1 on the upstream side has a negative pressure due to the infusion operation of the peristaltic infusion pump, and it is determined that the infusion line on the upstream side of the load sensor 14 is clogged. it can. The control means 4 determines upstream blockage based on such a waveform, stops the pump mechanism 3 and performs abnormality notification.

  The waveform shown in FIG. 6C shows that the inside of the infusion tube 1 is only air and there is no infusion agent. Compared with the waveform when normal infusion shown in FIG. 5A is performed, the output signals in the sections C and A are extremely low. This waveform indicates that the pump mechanism 3 is idling and the inside of the infusion tube 1 is only air, and it can be determined that the medical container is empty. Even when such a waveform is sampled, the control means 4 stops the pump mechanism 3 and notifies the user.

  The waveform shown in FIG. 6D shows that air bubbles are mixed in the infusion solution inside the infusion tube 1. This waveform shows an intermediate pressure between the time when the normal infusion shown in FIG. 5A is performed in the sections A and C and the case where the inside of the infusion tube 1 shown in FIG. It is to show. The control means 4 determines that air bubbles are mixed in based on such a waveform, and stops the pump mechanism 3 to notify the abnormality.

  As described above, the infusion tube 1 is closed above and below the load sensor 14 in accordance with the liquid feeding operation, and the change in pressure generated by the volume change generated in the infusion tube 1 in the closed region is detected, so that the infusion line 1 It is possible to easily detect not only blockage but also bubble contamination and other abnormalities. Since a plurality of abnormalities can be detected using one load sensor 14 without using an ultrasonic sensor as a detector, it is possible to prevent an increase in cost and size of the peristaltic infusion pump.

  By the way, it is preferable to correct the detection signal so as to improve the correlation between the pressure inside the infusion tube 1 and the output signal of the load sensor 14 because the accuracy of the load sensor 14 can be further improved. That is, as shown in FIG. 7A, the sensor support member 15 having the load sensor 14 attached to the tip is moved by the sensor cam 16 supported by the camshaft (sensor moving means). As a result, the load sensor 14 is temporarily separated from the infusion tube 1 only when the camshaft reaches a predetermined rotation angle (specifically, the same rotation angle 270 degrees as in the state of FIG. 3A). At other rotation angles, as shown in FIG. 7B, the state in which the load sensor 14 is in contact with the infusion tube 1 is maintained.

  When the load sensor 14 is separated from the infusion tube 1, the output signal of the load sensor 14 is collected by the control means 4. The signal output from the load sensor 14 at this time is an output signal that is an error when no force is applied to the load sensor 14. Next, the output signal at this time is stored as a correction value in the storage means included in the control means 4. Then, the correction means provided as a function of the control means 4 corrects the output signal at the time of pressure detection using this correction value. Thereby, the detection accuracy of the load sensor 14 is improved.

  In the structure demonstrated above, it demonstrated on the assumption that the infusion tube which has flexibility was equipped with sufficient rubber elasticity. However, the elasticity of commercially available infusion tubes varies greatly, and there are also hard and thin infusion tubes. In such a case, by configuring the finger pressure contact surface of the presser plate 2 with a sheet-like material having rubber elasticity, the volume change of the minute portion sandwiched between the pressure fingers due to the liquid feeding operation increases. As a result, the pressure change also increases, and a large electrical signal output can be obtained from the load sensor.

  On the contrary, when the thickness of the infusion tube 1 is too thick and too soft, the volume of the minute portion sandwiched between the pressure fingers becomes too small, and the liquid in the infusion tube 1 hardly remains. Then, since there is no part that causes a volume change, the load sensor can hardly obtain a change in electrical output.

  In such a case, as shown in FIG. 9, protrusions that project the both sides of the mounting portion of the infusion tube 1 of the pressing plate 2 to the pressure contact fingers f <b> 1 to f <b> 12 are provided, and the pressure contact fingers f <b> 1 are provided on the protrusions. The infusion pump according to the present embodiment is appropriately used even when the infusion tube 1 is thick and soft by configuring the infusion tube 1 so as not to be crushed more than necessary by abutting the tip of ˜f12. be able to.

[Second Embodiment]
Next, a peristaltic infusion pump according to a second embodiment of the present invention will be described with reference to FIGS. The peristaltic infusion pump according to the second embodiment differs from that according to the first embodiment in that the number of pressure contact fingers is 14 and the fifth cam m5 is a deformed cam described later instead of the actuator 18. However, other configurations are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted.

  In the cams m1 to m14 of the second embodiment, the phase in the eccentric direction with respect to the camshaft 5 is shifted by 30 degrees, and the first cam 13 and the 13th cam m13 are set to the same phase. m2 and the 14th cam m14 are set to the same phase. Thereby, the area | region corresponded to the area A of 1st Embodiment is expanded in 2nd Embodiment, In this area A, the infusion tube 1 is pressed by the 5th press-contact finger f5 with the deformed cam m5 ', and the volume is changed. ing.

  Since the fifth cam m5 is a deformed cam m5 ', the normal pressure contact finger shown in FIG. 2 causes the protruding portion to be caught in the cam engaging portion 8 and cannot rotate. Therefore, a smooth operation can be performed on the fifth press contact finger f5 by using a press contact finger having a tiltable swinging portion as shown in FIG. 4B.

  FIG. 10A shows a state in which the twelfth press contact finger f12 protrudes most. FIG. 10B shows a state in which the first pressure contact finger f1 and the thirteenth pressure contact finger f13 protrude most. FIG. 10C shows a state where the second pressure finger f2 and the fourteenth pressure finger f14 protrude most. FIG. 10D shows a state in which the third press contact finger f3 protrudes most. FIG. 10E shows a state in which the fourth press contact finger f4 protrudes most.

  As shown in FIG. 11, in addition to the pressing surface 9 as the eccentric direction, the deformed cam m5 ′ includes a deformed surface 19 in which a part of the outer peripheral surface protrudes substantially in the radial direction as the second pressing surface. . When the deformed surface 19 presses the infusion tube 1 in the section A, the infusion tube 1 undergoes a volume change. In the second embodiment, the deformed cam m5 'and the fifth press contact finger f5 correspond to the volume changing means.

  The upper part of FIG. 12 is a diagram showing the transition of the state in which the pressure contact fingers f <b> 1 to f <b> 14 close the infusion tube 1 according to the rotation angle of the camshaft 5. The state enclosed by the square is shown closed. The lower part of FIG. 12 shows the output value of the load sensor 14 detected according to the rotation angle of the camshaft 5. The uppermost waveform is normal, and the second waveform from the top contains air bubbles. The third waveform from the top is blocked downstream of the peristaltic infusion pump of the infusion tube 1, and the bottom waveform is blocked upstream of the peristaltic infusion pump of the infusion tube 1. It shows the state.

  In the peristaltic infusion pump according to the second embodiment, the infusion tube 1 is a finger pump type having a plurality of pressure-contacting fingers that can be crushed freely, and more (14 pieces) than the normal number (12 pieces) that is normally required. ), The ratio of the closed region in the pump cycle is expanded.

  Here, the normal number will be described. First, when each press contact finger f1 to f14 is pressed by a plurality of cams m1 to m14 provided by being displaced to the camshaft 5 by a predetermined angle (30 °), the camshaft 5 is rotated once. In the meantime, in order to crush the infusion tube 1 at one or more places, it is necessary to prepare the cams m1 to m12 and the pressure contact fingers f1 to f12 at least for the camshaft 5 to make one round. For example, when the predetermined angle is 30 °, in order to continue to crush the infusion tube 1 at one or more locations while the camshaft 5 makes one rotation, twelve cams m1 to m12 and press contact fingers f1 to f12 are used. Is a minimum requirement. Therefore, the normal number in the present embodiment is defined as the number of press contact fingers f1 to f12 that are at least necessary for continuing to crush the infusion tube 1 at one or more locations while the camshaft 5 rotates once.

  As described above, by extending the ratio of the closed region in the pump cycle, it is possible to secure a long time for measuring the pressure. For example, the detection value is subjected to low-pass filter processing or a plurality of detections. The values can be averaged, and can be made less susceptible to noise.

[Third Embodiment]
Next, a peristaltic infusion pump according to a third embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 13, the peristaltic infusion pump of the third embodiment is a roller-type peristaltic infusion pump. The peristaltic infusion pump according to the third embodiment is attached to a substantially triangular rotor 31 rotatably arranged on a base 30 (see FIG. 14) and to three vertex portions of the rotor 31, respectively. A roller 33 and a stator 35 having an arcuate inner peripheral surface 35a formed so as to cover the rotor 31 and the roller 33 are provided.

  As shown in FIG. 14, the stator 35 includes a fixed portion 37 fixed to the base 30 and a pair of movable portions 39 having one end rotatably connected to the fixed portion 37. An inner peripheral surface 35 a of the stator 35 is provided on the movable portion 39. FIG. 14 shows a state where the movable part 39 is opened, and FIG. 13 shows a state where the movable part 39 is closed.

  Referring to FIG. 13, the movable portion 39 is provided with a fixing groove 39 a for sandwiching and fixing the infusion tube 1 while being positioned on the side opposite to the fixing portion 37 in the closed state. The fixed portion 37 is provided with a pressure receiving plate 41 and a load sensor 43 that detects the pressure received by the pressure receiving plate 41.

  Further, a slider 45 disposed on the base 30 so as to be opposed to the pressure receiving plate 41 with a gap slightly smaller than the outer shape of the infusion tube 1 is provided so as to freely advance and retract toward the pressure receiving plate 41. ing.

  As shown in FIG. 14, the infusion tube 1 is attached by being sandwiched between the pressure receiving plate 41 and the slider 45 and in the fixing groove 39a with the pair of movable portions 39 opened. Then, by closing the pair of movable portions 39, the infusion tube 1 is mounted on a roller-type peristaltic infusion pump as shown in FIG.

  FIG. 16 shows a state when the rotation angle of the rotor 31 is 0 °. In the state of FIG. 16, the infusion tube 1 is crushed only by the roller 33 positioned at the lowermost position in FIG. 16, and the other rollers 33 do not crush the infusion tube 1.

  The roller-type peristaltic infusion pump of this embodiment checks the output value of the load sensor 43 when the rotation angle of the rotor 31 of FIG. 16 is 0 °, and the output value at this time is the upstream side of the infusion tube 1. If the infusion tube 1 is less than a predetermined value indicating a normal state where no occlusion has occurred (hereinafter referred to as an upstream occlusion predetermined value), the infusion tube 1 may be occluded upstream of the infusion pump. If there is, the user is notified by an alarm or the like.

  When the rotor 31 is rotated 12 ° from the state of FIG. 16 and the rotation angle of the rotor 31 is 12 °, the roller-type peristaltic infusion pump is in the state shown in FIG. In the state of FIG. 17, the uppermost roller 33 also crushes the infusion tube 1, and in the infusion tube 1, the uppermost roller 33 and the lowermost roller 33 define a closed region. To do. The roller 33 located on the right side of FIG. 17 contacts the slider 45, but at this time, the slider 45 has not yet moved.

  Then, when the rotor 31 is rotated 30 ° from the state of FIG. 16 and the rotation angle of the rotor 31 is 30 °, the roller-type peristaltic infusion pump is in the state shown in FIG. In the state where the rotation angle of the rotor 31 shown in FIG. 18 is 30 °, the closed region is still defined by the uppermost roller 33 and the lowermost roller 33.

  18 moves the slider 45 toward the pressure receiving plate 41, and the slider 45 presses the portion of the infusion tube 1 disposed between the slider 45 and the pressure receiving plate 41. The roller-type peristaltic infusion pump of this embodiment checks the output value of the load sensor 43 when the rotation angle of the rotor 31 of FIG. 18 is 30 °, and the output value at this time is a predetermined value indicating a normal state. If the value is less than the value, the user is notified by an alarm or the like that air bubbles may be mixed in the infusion tube 1. The one-dot chain line in FIG. 18 indicates the position of the slider 45 before moving toward the pressure receiving plate 41.

  Then, when the rotor 31 is rotated 48 ° from the state of FIG. 16 and the rotation angle of the rotor 31 is 48 °, the roller-type peristaltic infusion pump is in the state shown in FIG. In the state where the rotation angle of the rotor 31 shown in FIG. 19 is 48 °, the closed region is still defined by the uppermost roller 33 and the lowermost roller 33.

  Then, when the rotor 31 is rotated 60 ° from the state of FIG. 16 and the rotation angle of the rotor 31 is 60 °, the roller-type peristaltic infusion pump is in the state shown in FIG. In the state where the rotation angle of the rotor 31 of FIG. 20 is 60 °, the infusion tube 1 is crushed only by the uppermost roller 33 in FIG. 20, and the other rollers 33 crush the infusion tube 1. Not.

  The roller-type peristaltic infusion pump of this embodiment checks the output value of the load sensor 43 when the rotation angle of the rotor 31 of FIG. 20 is 60 °, and the output value at this time is the downstream side of the infusion tube 1. In the case where it exceeds a predetermined value (hereinafter, referred to as a downstream-side blocking predetermined value) indicating a normal state in which no blockage occurs, there is a possibility that the infusion tube 1 is blocked on the downstream side of the infusion pump. If there is, the user is notified by an alarm or the like.

  When the output value of the load sensor 43 is equal to or smaller than the downstream blocking predetermined value, the rotor 31 is further rotated by 60 ° from the state shown in FIG. 20, and the rotation angle of the rotor 31 is set to 120 °.

  In the roller-type peristaltic infusion pump of this embodiment, the processing described with reference to FIGS. 16 to 20 is repeated in order until the rotor 31 rotates once and rotates 360 ° to return to the rotation angle 0 ° in FIG. To do. That is, while the rotor 31 rotates once, the peristaltic infusion pump executes the processing described with reference to FIGS. 16 to 20 three times.

  21A to 21D and 22A to 22D are diagrams showing the relationship between the rotation angle of the rotor and the waveform of the output signal of the load sensor. FIG. 21A is a diagram showing a waveform in a normal state. FIG. 21B is a diagram illustrating a waveform when the position of the container is low. FIG. 21C is a diagram showing a waveform when the position of the patient is high. FIG. 21D is a diagram showing a waveform in the case of liquid feeding in the reverse direction or an abnormal positional relationship between the medical container and the human body.

  FIG. 22A is a diagram illustrating a waveform of an output signal of the load sensor in the downstream closed state. FIG. 22B is a diagram illustrating a waveform of an output signal of the load sensor in the upstream closed state. FIG. 22C is a diagram showing a waveform of the output signal of the load sensor when the infusion tube is empty. FIG. 22D is a diagram illustrating a waveform of an output signal of the load sensor when air bubbles are mixed therein.

1 Infusion tube 2 Presser plate (presser)
2a Flat surface 2b Spring (biasing means)
3 Pump mechanism 4 Control means (bubble detection means, blockage detection means, positional relationship determination means)
5 Camshaft 6 Drive motor (rotation drive means, angle detection means)
7 pressure contact portion 8 cam engagement portion 9 pressing surface 10 driven pulley 11 drive shaft 12 drive pulley 13 belt 14 load sensor (pressure detection means)
15 Sensor support member 16 Sensor cam (sensor moving means)
17 receding surface 18 actuator 19 deformed surface 30 base 31 rotor 33 roller 35 stator 35a inner peripheral surface 37 fixed portion 39 movable portion 39a fixing groove 41 pressure receiving plate 43 load sensor 45 slider f1 first pressure contact finger (upstream pressure contact finger)
f4a Oscillating part f12 12th pressure contact finger (downstream pressure contact finger)
f1 to f12 pressure finger m1 first cam (upstream cam)
m2 Second cam (other cams)
m12 12th cam (downstream cam)
m1-m12 cam

Claims (11)

A peristaltic infusion pump for connecting a medical container containing a liquid and a human body and forcibly flowing the liquid flowing in a flexible infusion tube by peristally moving the infusion tube. ,
A plurality of closing points for preventing the flow of the liquid in the infusion tube, and one closing point formed with the progress of a peristaltic movement for liquid feeding and another closing point; Volume changing means for changing the volume of the closed region sandwiched between;
Pressure detecting means for detecting the pressure in the infusion tube in the closed region;
Bubble detection means for determining the presence or absence of air mixed in the infusion tube based on a change in the amount of change in pressure of the infusion tube detected by the pressure detection means by adding a volume change by the volume change means; A peristaltic infusion pump characterized by comprising: The peristaltic infusion pump according to claim 1,
The pressure when the upstream side of the pressure detection means is closed and the downstream side of the pressure detection means is released (hereinafter referred to as downstream pressure);
Said downstream side is closed the pressure detecting means, the pressure at the upstream side of the pressure detecting means is released (hereinafter, referred to as upstream pressure) is detected and, the by the pressure detecting means,
A peristaltic infusion pump comprising a blockage detecting means for detecting blockage of the infusion tube based on the downstream pressure and the upstream pressure. The peristaltic infusion pump according to claim 1 or claim 2,
A finger pump type comprising a plurality of press-fitting fingers that can freely crush the infusion tube,
A plurality of cams arranged to be displaced by a predetermined angle, each of which advances and retracts the plurality of press contact fingers;
A camshaft that pivotally supports the plurality of cams;
A drive source for rotating the camshaft,
The minimum number of the pressure fingers required to continue to crush the infusion tube at one or more locations during one rotation of the camshaft is defined as “normal number”,
By installing a large number of the pressure fingers than the normal number, peristaltic infusion the ratio of the closure area occupied in the pump cycle, characterized by extended than when installing the pressure fingers of the normal number of pump. The peristaltic infusion pump according to claim 3 ,
The camshaft full Ingaponpu is configured to impart a volume change in the closed region by profiled cam integrally assembled,
A peristaltic infusion pump characterized in that a separate drive source for applying a volume change in the closed region is unnecessary. The peristaltic infusion pump according to claim 1 or claim 2,
A roller-type peristaltic infusion pump,
The stator is divided, the pressure detecting means is installed between the stators, and the volume change in the closed region is given by pressing the movable piece against the infusion tube by using one roller. Peristaltic infusion pump. The peristaltic infusion pump according to any one of claims 1 to 3,
The peristaltic infusion pump, wherein the volume changing means imparts a volume change to the infusion tube by applying an external force to the infusion tube. The peristaltic infusion pump according to claim 6 ,
A finger pump type comprising a plurality of press-fitting fingers that can freely crush the infusion tube,
A plurality of cams for advancing and retreating the plurality of pressure contact fingers,
A camshaft that pivotally supports the plurality of cams;
A drive source for rotating the camshaft;
And a angle detecting means for detecting a rotational angle of the cam shaft,
The volume changing means synchronizes the action of an external force on the infusion tube with the pressure detected by the pressure detecting means based on the angle detected by the angle detecting means. . The peristaltic infusion pump according to any one of claims 1 to 7 ,
The peristaltic infusion pump, wherein the pressure detection means is a load sensor that detects a force of the infusion tube to expand due to a pressure inside the infusion tube. The peristaltic infusion pump according to claim 8 ,
The peristaltic infusion pump characterized in that the load sensor is a sensor employing a semiconductor strain gauge bridge. The peristaltic infusion pump according to claim 8 or 9 ,
Sensor moving means for separating the load sensor from the infusion tube;
Storage means for storing the output of the load sensor when the load sensor is separated from the infusion tube;
Peristaltic infusion pump, characterized in that it comprises a correction means for correcting the output of said load sensor values detected from the infusion tube stored in the storage means. The peristaltic infusion pump according to any one of claims 1 to 10 ,
A finger pump type comprising a plurality of press-fitting fingers that can freely crush the infusion tube,
It is provided with a positional relationship determining means for determining the quality of the height position relative to the medical container and the human body based on the pressure detected by the pressure detecting means when the pressure contact finger is in pressure contact with the infusion tube. Peristaltic infusion pump.