JP3290263B2 - Drive control method of peristaltic infusion pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive stop of a peristaltic infusion pump for injecting a liquid to be transported stored in a liquid container.
The method relates to a stoppage control method , for example, infusing a nutrient solution or a drug solution stored in an infusion bag to administer the solution into a living body.
The present invention relates to a drive control method for a peristaltic infusion pump .

[0002]

2. Description of the Related Art For example, in the medical field, nutrient solutions,
In order to administer a parenteral liquid such as a drug solution or a saline solution into a living body, a medical infusion system for injecting such a liquid has been used. FIG. 9 shows an example of this infusion system, which includes an infusion bag 54 for storing a nutrient solution and the like, and an infusion pump 51 for infusing the nutrient solution and the like. This infusion pump 51 is a peristaltic type (peristaltic finger type) as disclosed in Japanese Patent Publication No. 61-55,393.
An infusion pump of this type is known, and a tube mounting portion 53 to which a flexible tube 55 connected to an infusion bag or the like is mounted is provided on the front surface of the main body 51a. The tube mounting portion 53 is provided with a pump portion 57 for closing and injecting the liquid passing through the tube 55 by peristaltic movement of the finger so as to sequentially move the crushed position of the liquid feeding tube 53 and injecting the liquid. A door 52 opposite to 57 is attached to be openable and closable. A back plate 58 that presses the tube 55 with a predetermined pressure in a direction toward the pump unit 57 is provided on the door inner surface 52a facing the pump unit 57. A back plate 5 is provided between the back plate 58 and the door inner surface 52a.
A spring for urging a repulsive force for pressing the spring 8 toward the pump portion 57 is attached.

The pump section 57 of the infusion pump 51 is driven by a stepping motor or the like. By controlling the rotation speed of this motor, the flow rate per unit time (for example, one hour) can be set within a predetermined range. It has become. Also, since the amount of infusion per rotation of the motor drive shaft is known in advance, by counting the number of rotations of the motor drive shaft, the integrated amount of infusion after starting the infusion is calculated. . Further, the infusion pump 51
Also has the function of setting the planned infusion volume.

[0004] If an infusion scheduled amount and an infusion flow rate are set, it is detected for a long time (about 24 hours) by the infusion sensor 59.
Is configured to be able to perform infusion automatically over a period of time.

[0005] This type of infusion pump 51 incorporates an infusion amount monitoring device that indicates that the infusion has been completed. The conventional infusion amount monitoring device calculates by counting the number of rotations of the motor drive shaft. When the infusion integrated amount or the infusion integrated amount calculated by counting the number of drops of the drug solution or the like matches the preset infusion scheduled amount, the infusion is performed by turning on a lamp or emitting a buzzer sound. It indicates that it has been completed.

[0006]

However, this type of infusion pump must be able to continuously vary the flow rate per unit time from a minimum to a maximum flow rate, and accordingly, it is necessary to drive a stepping motor. The pulse frequency must also be controlled continuously.

As shown in FIG. 8, a stepping motor has a resonance region where vibration is particularly large in a specific frequency region as shown in FIG. 8, and an infusion pump using a pulse speed region continuously including the above-mentioned region. However, there is a problem in that vibration and noise increase at a certain flow velocity, and the patient receiving treatment feels very uncomfortable.

The present invention has been made to improve the above-mentioned problems of the conventional peristaltic infusion pump,
An object of the present invention is to provide a drive control method for a low-noise peristaltic infusion pump .

[0009]

Means for Solving the Problems According to the present invention for achieving the above object, a plurality of fingers sequentially pushes an infusion tube.
Pressure to transfer the drug solution in the infusion tube.
Control method of a peristaltic infusion pump for infusion
The step of setting the volume in the input section and the set infusion flow rate
Pulse speed is required for either 2-phase excitation or 1-2-phase excitation
Determining whether or not the
Pulses excited based on the phase excitation method
To the peristaltic pump section
And a drive of a peristaltic infusion pump characterized by comprising
Dynamic control method.

[0010]

The transported liquid stored in the liquid storage container is infused at the set infusion flow rate. By providing a circuit that excites the motor avoiding the resonance region of the step motor, the drive control of the low-vibration, low-noise peristaltic infusion pump is provided.
A method can be provided.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a peristaltic infusion pump according to an embodiment will be described in detail with reference to the accompanying drawings. FIG. 1 is a front view of a peristaltic infusion pump 1 according to the present invention.

Referring to FIG. 1, reference numeral 2 denotes a first display unit which shows an LED or the like for notifying an abnormality of the peristaltic infusion pump 1 and the like, and is provided in a tube (not shown) mounted on the peristaltic infusion pump 1. When air bubbles are detected, peristaltic infusion pump 1
When the blockage of the tube attached to the peristaltic infusion pump 1 is detected, and when the flow rate of the liquid in the tube attached to the peristaltic infusion pump 1 is not within a predetermined set flow rate, the liquid in the tube attached to the peristaltic infusion pump 1 When there is no infusion, the display unit indicates an abnormality such as a state where the door 12 of the peristaltic infusion pump 1 is open or a state where the door 12 is not completely closed, and a case where the infusion is completed. The display unit may display each of them separately. Reference numeral 3 denotes a second display unit for digitally displaying an integrated amount of infusion, an infusion flow rate, an estimated infusion amount, and the like. The integrated amount is obtained by calculating the total infusion amount from the start of the infusion to the present time from the flow rate per unit time based on a table stored in advance and displaying the calculated amount. Reference numeral 4 denotes a changeover switch for switching between the display of the flow rate and the expected amount on the second display unit 3, 5 an integration clear key for clearing the integration amount, and 6 a key for setting the number of droplets. Further, 7a is a coarse adjustment key (two digits) for setting the infusion flow rate (infusion time per unit time, for example, infusion rate per hour), and 7b is for setting the infusion flow rate and the infusion volume of the infusion. The upper keys of 7a and 7b are each incremented by +10 and +1 each time the upper key is pressed, and the lower keys of 7a and 7b are each incremented by -10 each time they are pressed. , -1. Flow rate setting is 7a, 7
When an input is made with the key b, a pulse having a pulse frequency corresponding to the set flow rate is given to the motor drive circuit, and the rotation speed of the motor drive shaft is controlled. 8
Is a power key, and if the power is a battery, an indication to that effect is displayed, and if the voltage is lower than a predetermined value, it flashes.
9 is infused at a predetermined flow rate while the fast-forward key is pressed. Reference numeral 10 denotes a key for starting and stopping an infusion, which also has a mute key function of an alarm buzzer. Reference numeral 11 denotes a knob for opening and closing the door 12, and reference numeral 13 denotes a grip.

The medical infusion system shown in FIG. 2 is used for injecting a drug solution (infusion agent) into a living body, performing automatic infusion, and the like, and includes an infusion bag 14 containing the drug solution. And a peristaltic infusion pump 1.

The infusion bag 14 contains a nutrient solution, a drug solution,
A predetermined amount of a parenteral liquid (corresponding to a liquid to be transported) such as a physiological saline solution is filled and locked on an upper portion of a stand (not shown). A drip tube 21 is provided at the lower end of the infusion bag 14.
Is connected to one end of the flexible tube 15. The drip tube 21 is provided with a droplet detection sensor 20 for detecting a drop of a drug solution or the like falling from the infusion bag 14. The droplet detection sensor 20 includes an optical sensor 22. The optical sensor 22 includes a light emitting element (for example, an infrared light L).
ED) 22a and light receiving element (eg, phototransistor)
22b, and is provided so that the light from the light emitting element 22a is blocked by the drop. Infusion bag 1
4, the light from the light emitting element 22a is blocked or passed by the dropped liquid as the chemical solution falls,
The light receiving element 22b outputs, for example, an off signal when receiving the light from the light emitting element 22a, and outputs an on signal that is equal to or less than a preset threshold value when the light is blocked by the droplet. By counting this ON signal, the number of drops of the chemical solution or the like is detected. In addition, the drip tube 21 is configured such that 15 drops
The number of drops per unit volume (for example, 1 cc) is predetermined, such as 1 cc for 19 drops, 1 cc for 19 drops, and 1 cc for 60 drops. Therefore, by counting the number of drops of the liquid medicine or the like, that is, the ON signal from the light receiving element 22b, and dividing this by the number of drops per unit volume, the infusion integrated amount can be calculated. This integrated amount is displayed on the second display unit.

If the dropping of the drug solution or the like is not detected even after the lapse of a predetermined time, that is, if the ON signal from the light receiving element 22b is not detected during the predetermined time, it is determined that the drug solution or the like stored in the infusion bag 14 has run out. Can be determined. The infusion pump 1 is provided with a tube mounting portion 15 to which a flexible tube 15A connected to the infusion bag 14 or the like is mounted. The tube mounting portion 15 has a peristaltic pump portion 17 for moving a drug solution passing through the tube 15A.
And a door 12 facing the peristaltic pump unit 17 is attached so as to be openable and closable. Further, as shown in FIG. 2, a back plate 18 that presses the tube 15 </ b> A in a direction toward the peristaltic pump unit 17 is provided on the door inner surface 12 a facing the peristaltic pump unit 17. Between the back plate 18 and the door inner surface 12a, a spring nud biasing member 20 for biasing the back plate 18 toward the peristaltic pump unit 17 with a predetermined pressing force is attached. ing. Also,
The peristaltic pump unit 17 is covered with a waterproof sheet member to prevent a chemical solution from entering the peristaltic pump unit 17.

As shown in FIG. 3, the peristaltic pump section 17 includes a plurality of (for example, six) fingers 25 which can move forward and backward with respect to the mounted tube 15A, and slidably move these fingers. And a casing 26 for holding. The casing 26 is composed of a pair of casing members 27 that are abutted against each other.
A holding groove 28 that slidably holds each finger 25 is formed in the shelf 6 in a shelf shape. In the casing 26, a support shaft 29 is rotatably mounted via a bearing 30, and a plurality of (for example, six) eccentric cams 31 are shifted on the support shaft 29 by a predetermined angle. Is fixed. The support shaft 29 has a D-shaped cross section in order to prevent a positional displacement between the support shaft 29 and a timing pulley 60 described later due to rotation. Finger 25
Has a substantially plate-like shape, and has a cam hole 32 with which the eccentric cam 31 slides. The portion of the support shaft 29 fitted to the eccentric cam 31 may have an ordinary circular cross section other than the D-shaped cross section. As shown in FIG. 3, one end of the support shaft 29 protruding from the casing 26 is connected to a rotation driving unit including a timing pulley 60, a timing belt 61, a motor (not shown), and the like.

When the motor is operated to rotate the support shaft 29, each of the eccentric cams 31 fixed to the support shaft 29 with the phase shifted is provided on the inner peripheral surface of the cam hole 32 of the corresponding finger 25. It rotates while sliding. As a result of this cam action, each finger 25 starts moving forward from the upper part while sliding in the holding groove 28 as a tube pressing means.
The tube 15A is pressed against the back plate 18 to close the flow path of the tube 15A. Further, the finger 25 that has moved to the forward limit moves toward the backward limit as the support shaft 29 further rotates, and the blockage is released. In this way, by repeating the operation of sequentially moving the fingers 25 located above to the forward limit, the tube 15A
Is closed, ie, the closing point 15a sequentially moves downward along the longitudinal direction of the tube 15A, so that the liquid in the tube 15A is infused from the suction side to the discharge side. Further, in order to prevent pulsation, the phase at which the lowermost finger 25 moves to the forward limit and the uppermost finger 25 starts to advance is advanced by a predetermined time using the encoder 47. This eliminates the need to provide a finger for pulsation correction.

As is well known, the stepping motor can control the rotation speed of the motor drive shaft by controlling the pulse frequency of the pulse applied to the motor drive circuit. Therefore, the peristaltic pump unit 17 controls the frequency of the pulse applied to the stepping motor, so that the infusion rate per unit time is set within a predetermined range.

A transport liquid amount integrating means 45 for integrating the amount of liquid infused by the infusion pump 1 is provided with a timing pulley 60 connected to the support shaft 29 as shown in FIGS.
And an optical sensor 48. The outer peripheral flange of the timing pulley 60 is an encoder 47 in which one slit 47a is formed. As shown in FIG. 5, the optical sensor 48 includes a light emitting element (for example, an infrared LED) 48a and a light receiving element (for example, a phototransistor) 48b, and is provided so that light from the light emitting element 48a passes through the slit 47a. ing. As described above, by forming the conventional encoder unit provided separately from the pulley integrally with the timing pulley 60, the outer dimensions of the infusion pump 1 can be reduced. Further, the center hole 60a of the pulley 60 into which the support shaft 29 is inserted is formed in a substantially D-shape.
By making a a non-circular, no displacement (slip) occurs between the pulley 60 and the support shaft 29, and the rotation speed of the support shaft 29 can be accurately detected by the encoder 47. It should be noted that the present invention does not hinder a pump having an encoder of another component. In addition, the shape and the like of the encoder are not limited to these.

The driving of the motor is transmitted to the timing belt 61, the timing pulley 60, and the support shaft 29. When the encoder 47 rotates together with the timing pulley 60, light from the light emitting element 48a is blocked or passes through the slit 47a. The light receiving element 48b outputs, for example, an ON signal when receiving the light from the light emitting element 48a, and outputs an OFF signal when the light is blocked. By counting the ON signal, the number of rotations of the support shaft 29 is detected.
The infusion amount per rotation of the support shaft 29 is known in advance. Therefore, the rotation speed of the support shaft 29, that is, the light receiving element 48b
Is counted, and this signal is multiplied by the amount of infusion per rotation of the support shaft 29 to calculate the integrated amount of infusion. As described above, since the integrated amount of liquid infusion can be calculated based on the number of drops detected by the droplet detection sensor 20, the transport liquid amount integrating means 45 may be configured by the droplet detection sensor 20.

The second display section 3 is preferably constituted by an LED or an LCD having seven segments. Alternatively, the LEDs may be arranged in a row, and a predetermined display may be indicated by turning on, off, or blinking the LEDs. Further, an error display can be performed using this segment. In addition, a buzzer may be provided in the time display section to indicate an infusion completion alarm or the like, and various alarms may be identified by making the buzzer sound an intermittent sound or a continuous sound. Further, the display unit 3 and the buzzer may be connected to a so-called nurse call system, and a predetermined display based on the calculation result may be displayed at the nurse center.

Next, the infusion pump 1 will be described with reference to the flowcharts shown in FIGS. 1 and 6 and the block diagram shown in FIG.
The operation of will be described.

When the program is started, various variables are initialized, and the planned infusion volume is set with the setting keys 7a and 7b of the key input unit 77, which is stored in the storage unit 76 and the first display unit 3 (Step S1). Next, the infusion flow rate V is set on the setting keys 7a and 7
b, and this is also stored in the storage unit 76 and displayed on the first display unit 3 (step S2). It is determined that input by double or triple pressing of keys other than the simultaneous pressing of the switching key 4 and the fine adjustment key 7b is invalid. In addition, the switching key can be input during the infusion operation, but interrupt processing is prohibited for the setting of the scheduled infusion amount Q and the setting of the infusion flow rate V.

When the switch 10 is operated and the start of infusion is instructed by the output from the control unit 74 (step S3).
Sounded buzzer indicating the infusion start, the initial motor speed M ₀ is the step motor is calculated is driven. M ₀ p at this time
The method of determining ps is described below (step S4).

When the infusion to be used and the infusion flow rate V are determined, the drive pulse speed in the two-phase excitation is determined by the outputs from the storage means 76 and the controller 74. X is the resonance region in two-phase excitation.
_{Assuming that pps} <resonance region <Y _pps , the initial speed M ₀ is X <M ₀ <
If it is within the range of Y, the control section 74 recalculates the pulse speed in the 1-2 phase excitation and outputs the pulse pattern in the 1-2 phase excitation. When M ₀ ≦ X, Y ≦ M ₀ , a pulse pattern of two-phase excitation is output without changing the pulse speed of M ₀ . Thus, the motor starts rotating (step S
5).

The peristaltic pump 17 is driven by the rotation of the motor 78 via the timing belt 61, the tubes 15 A are sequentially pressed, and infusion from the infusion bag 14 is started. When the state shifts to the drip control, the drip sensor 22
Is compared with the reference drip time, and the controller 74 changes the current motor speed in step S7 according to the difference, and the infusion is continuously performed. Also in this case, it is confirmed by the two-phase excitation whether the changed pulse speed falls within the range of X <M ₁ <Y as described above.
If the phase is not entered, the motor is driven by two-phase excitation.

When it is determined that the infusion amount i has reached the planned infusion amount Q and the infusion has been completed, an infusion completion alarm is issued. This infusion completion alarm is also indicated to an operator or the like by turning on the lamp of the display unit 3 or emitting a buzzer sound by the buzzer / nurse call output unit 72. When the liquid medicine container or the like stored in the liquid storage container (infusion bag) 14 runs out during the infusion operation, the empty liquid display section 2d of the first display section 2 is displayed, and the operator is required to replace the infusion bag 14 with the operator. Etc. are required. In addition, if the display units 2 and 3 and the buzzer are connected to the nurse call system, various information and alarms associated with the infusion work can be collectively grasped at the nurse center,
There is no need for the nurse to look in advance about the operation status of the plurality of infusion pumps. The power supply unit 71 is an entire power supply unit of the peristaltic infusion pump, and may be a battery such as a nickel cadmium battery that can be charged from an external power supply. By using a rechargeable system, even in the case of a power outage or the like, safety can be improved by providing automatic switching means for power supply from the battery. Further, by using a DC battery for an automobile, it can be easily used as a power source even in an ambulance or the like. The various sensors 75 are connected to the tube 15
The detection of air bubbles in A, the detection of the open state of the door, the detection of a voltage drop, the completion of infusion, and the like are performed.

Next, the control method will be described in detail with reference to the vibration characteristics shown in FIG.

FIG. 8A shows the vibration characteristics of the motor when the step motor is driven by the two-phase excitation method. The vibration characteristics are simplified for the sake of explanation.

Now, the infusion pump has an infusion flow rate of 0 to 300 ml /
motor pulse speed corresponding to 0 to 2 k
pps. As shown in the figure, the stepping motor of the infusion pump has a large vibration component near the infusion flow rate of 150 ml / h (pulse speed 1 kpps), and the noise increases accordingly.

Attention is now directed to FIG. FIG. 7 shows vibration characteristics when the same step motor is driven by 1-2 phase excitation. 1-2-phase excitation is ２ of 2-phase excitation drive
When the motor is driven at the same pulse speed as the two-phase excitation, the rotation angle of the motor shaft is halved. or,
The vibration characteristics at the same frequency also have lower vibrations in the 1-2 phase excitation in the resonance region. Here, as is well known, the two-phase excitation method is a method in which current is sequentially supplied to two phases at all times to perform step feed, and the 1-2-phase excitation method excites one phase and two phases alternately. It is a method that is being done.

If a step motor is driven by utilizing this property, a low-vibration motor drive can be realized in the entire region of the two-phase pulse speed of 0 to 2 kpps. That is, 2
0 to 750 pps in phase excitation, 1250 to 2000
The range of pps is driven by two-phase excitation, and the range of 751 to 1249 pps in two-phase excitation is 1 by 1-2-phase excitation.
By driving at a pulse rate of 502 pps to 2498 pps, the use of the resonance region is completely eliminated, and a low-noise infusion pump can be provided.

[0033]

[0034]

As described above, according to the present invention ,
The infusion is performed by sequentially pressing the infusion tube with the fingers.
Peristaltic infusion pump for transferring chemicals in tubes
The drive control method is to set the infusion flow rate at the input section.
And the pulse speed required for the set infusion flow rate are two-phase excitation
To determine whether it is compatible with magnetic or 1-2 phase excitation.
And the excitation based on the determined phase excitation method.
The magnetized pulse is applied to the motor drive circuit,
The pump section is driven,
Driving peristaltic infusion pump with low vibration and low noise in volume range
A control method can be provided.

[Brief description of the drawings]

FIG. 1 is a front view of a peristaltic infusion pump according to the present invention.

FIG. 2 is a schematic configuration diagram showing an infusion system using a peristaltic infusion pump according to the present invention.

FIG. 3 is a sectional view showing a pump section shown in FIG. 1;

FIG. 4 is a perspective view showing a pump unit shown in FIG. 1;

FIG. 5 is a perspective view showing an example of an infusion amount integrating means shown in FIG. 1;

FIG. 6 is a flowchart showing an operation sequence of the infusion pump of the present invention.

FIG. 7 is a block diagram illustrating an operation circuit according to the present embodiment.

FIG. 8 is a diagram of a vibration characteristic depending on a difference in an excitation method.

FIG. 9 is a schematic configuration diagram showing an example of a medical infusion system.

[Explanation of symbols]

 14, 54 ... infusion bag (supply source) 22, 59 ... droplet detection sensor 1, 51a ... infusion pump (infusion means) 45 ... infusion amount integrating means 7a, 7b ... setting key 74 ... CPU (control unit)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-309274 (JP, A) JP-A-50-77818 (JP, A) JP-A-5-146505 (JP, A) JP-A-5-146505 31175 (JP, A) JP-A-51-101390 (JP, A) JP-B-51-25674 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61M 5/142 A61M 1 / 10 500

Claims (1)

(57) [Claims] 1. An infusion tube is sequentially pushed by a plurality of fingers.
Transfer the drug solution in the infusion tube by pressing
A drive control method of a peristaltic infusion pump for setting a flow rate of an infusion at an input unit, and determining whether a pulse speed required for the set infusion flow is two-phase excitation.
Determine whether or not one of the two-phase excitation is met
And the pulse excited based on the determined phase excitation method
Peristaltic pump section
Steps and, to a driving control of the peristaltic infusion pump, characterized in
Method.