JPH0470911B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is mainly used for medical purposes to deliver medicinal liquids into the human body, and by repeating a predetermined liquid delivery process. This invention relates to, for example, a peristaltic type infusion pump that continuously feeds liquid.

<Conventional technology> An infusion system using this type of infusion pump is
For example, it is configured as shown in FIG. That is, the medicine bottle 1 is attached to the upper end of the infusion tube set in which the infusion tube 3 is provided with the drip tube 2, the check valve 4, and the Y-shaped injection part 5 in order from the top, and the infusion pump 6 is attached to the lower part of the infusion tube set. It is attached. The infusion pump 6 has a built-in pressure detector 8 for detecting the internal pressure of the infusion tube 3, at a position on the upstream side of the pumping mechanism 7 of the linear peristaltic type in the flow direction of the drug solution, for example. This pressure detector 8 is attached to the infusion tube 3 in a circumscribed state to detect the internal pressure of the infusion tube 3.The purpose of providing this is to detect the occurrence of blockage on the upstream side of the infusion pump 6 during pumping operation. This is to detect the occurrence of a blockage state of the infusion tube 3 by utilizing the phenomenon in which the internal pressure of the infusion tube 3 becomes extremely low.

By the way, in the peristaltic infusion pump, the blocking part that presses the infusion tube 3 from the side and closes it moves from the upstream side to the downstream side as the pumping mechanism rotates or linearly reciprocates. Therefore, the medicinal solution in the infusion tube 3 is pushed out downstream, that is, it is fed.
Here, when the blocking part moves to the lowest position of the movement range, that is, in the final step of one cycle of pumping operation process, there is a blocking part at the highest position in addition to the lowest position, and then at the lowest position In the process of moving to the next cycle of pumping operation after the blockage is released, the volume inside the infusion tube 3 from the blockage at the top to the pump outlet temporarily increases due to the release of the blockage at the bottom. , the discharge pressure decreases, and there is a period of low discharge pressure, that is, a period of low discharge amount, until the uppermost blockage moves to a certain extent. In other words, in an infusion pump that repeats a predetermined pumping operation process as one cycle, the discharge pressure fluctuates in the process of transitioning from one cycle to the next, and the discharge volume fluctuates as shown in Figure 6. There is. As is clear from the figure, in one cycle T of the pumping operation process, there is a time period A with a high discharge amount and a time period B with a low discharge amount, and when these fluctuations are averaged, the discharge amount per unit time is shown by the broken line in the figure. The setting amount is shown as . In this type of infusion pump, it is impossible to eliminate fluctuations in the discharge amount in any existing method, and fluctuations in the discharge amount always exist, even if there are differences in degree.

<Problems to be Solved by the Invention> However, due to the above-described variation in the discharge amount, there is a problem in that the pressure sensor 8 malfunctions when the infusion pump is started. To explain in detail, the Y-shaped injection part 5 and the check valve 4 shown in FIG.
When the infusion tube set for two-liquid injection equipped with the infusion tube set is loaded into the infusion pump 6, at least one point of the infusion tube 3 is crushed and obstructed by the pumping mechanism 7. The medicinal fluid that has flowed into the infusion tube 3 is prevented from flowing down by the closed portion and is also prevented from moving upward by the check valve 4, and the internal pressure of the infusion tube 3 on the upstream side of the closed portion of the pumping mechanism 7 rises temporarily. When the infusion pump 6 is started to be driven in this state, the drug solution in the infusion tube 3 is moved downstream as the blocked part of the pumping mechanism 7 moves, and the internal pressure upstream of the blocked part of the infusion tube 3 decreases. becomes a steady value.
When this infusion pump 6 is started, if the pumping mechanism 7 is started from a state corresponding to time period B, which is the trough of fluctuation shown in FIG. 6, the internal pressure upstream of the blocked part of the infusion tube 3 gradually decreases. However, when the infusion tube 3 is started from a state corresponding to time period A, which is the peak of fluctuations shown in the same figure, the internal pressure of the infusion tube 3 on the upstream side of the blocked portion rapidly decreases because the discharge amount is large. On the other hand, the pressure sensor 8 of the infusion pump 6 is
Since the internal pressure upstream of the blockage point of the infusion tube 3 during pumping operation is constantly detected, when the infusion pump is started from a state corresponding to time period A, the internal pressure of the infusion tube 3 upstream of the blockage point is detected. is rapidly decreased, and the pressure detector 8 misidentifies this state as a blockage of the infusion tube 3 on the upstream side of the infusion pump, causing a malfunction in which an alarm is issued.

<Object of the Invention> The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide an infusion pump that can reliably prevent malfunction of a pressure detector when starting the pump with an extremely simple configuration. This is the purpose.

<Means for Solving the Problems> In order to achieve the above object, the infusion tube of the present invention continuously delivers fluid by repeating a predetermined pumping operation process by rotational motion or linear reciprocating motion as one cycle. An infusion pump comprising: a pumping mechanism for pumping liquid; and a pressure detector, which is disposed upstream of the pumping mechanism in the direction of infusion flow and detects the occurrence of a blockage state of the infusion tube based on the internal pressure of the tube; A specific phase or an arbitrary phase in one cycle of the pumping operation process of the pumping mechanism is detected by a detection member fixed to a part of the pumping mechanism that performs periodic motion so as to be integrally interlocked with the detection means of the detection member. and a start position control means for driving the pumping mechanism to a set phase based on the phase information of the phase detection means when the tube set is disconnected when the tube set is connected or disconnected. It is characterized by a configuration including the following.

<Function> A blade as a member to be detected is fixed to a drive shaft rotated by a motor of a drive source as a part that performs periodic motion of the pumping mechanism, and a photointerrupter as a detection means is attached such that its optical axis is aligned with the blade. The vane is installed at a position where it is blocked by the photointerrupter, and the vane is installed so that the vane intercepts the optical axis of the photointerrupter when the pumping mechanism reaches a desired phase in one cycle. for example,
Position the blade so as to block the optical axis of the photointerrupter during periods of low discharge volume, and perform operations to attach the infusion tube set to which the drug bottle is connected, for example, when the tube attachment door of the infusion pump is opened. Therefore, when the above-mentioned infusion tube set is not connected, the start position control means drives the pumping mechanism to a phase where the vanes block the optical axis of the photointerrupter, so that when the pump is started, the pumping mechanism is moved upstream from the tube blockage part of the pumping mechanism. The internal pressure of the side infusion tube will gradually decrease, and the pressure detector will not malfunction.

<Example> Hereinafter, preferred examples of the present invention will be described in detail based on the drawings.

FIG. 1 is an embodiment of the present invention showing a finger type linear peristaltic system.
In this embodiment, a pulse motor 10 is used as the drive source.
is used, and one rotation of the motor shaft 11 of this pulse motor 10 is
7 fingers 1 that are eccentrically attached to 1 in sequence
It corresponds to one cycle of the pumping operation process of the pumping mechanism 12 consisting of 2A to 12G. A back plate 13 is applied to the infusion tube 3 at a position opposite to the pumping mechanism 12. A blade 14 as a member to be detected is fixed in a cantilever manner to the tip of the motor shaft 11 by a set screw 15, and a photointerrupter 16 consisting of a light emitting element and a light receiving element serves as a means for detecting the blade 14.
However, the blade 14 is provided so as to block the optical axis of this.

The photointerrupter 16 is connected to a detection circuit 17 that outputs a single pulse signal based on the detection signal of the blade 14 that is output from this, and the output pulse of this detection circuit 17 is sent to the reset terminal R of the pulse counter 18 and the central control unit. 19 is input. The central control section 19 controls the entire device and has a calculation function. Based on the motor drive signal output from the central control section 19, a pulse signal is output from the motor pulse generation section 20. The motor drive unit 21 controls the rotation of the pulse motor 10. Further, the output pulses of the motor pulse generator 20 are counted by the pulse counter 18,
This count signal is input to the central control section 19.

Next, the operation of the above embodiment will be explained with reference to FIG. The central control unit 19 constantly monitors the entire device based on the flowchart shown in Fig. 2, and when infusing an infusion using the infusion tube, the infusion tube set shown in Fig. 5 is connected to the infusion pump. When the tube attachment door of the infusion pump is opened in order to attach the tube, a door open signal is input from the tube attachment door opening/closing detection circuit 22 to the central control unit 19, and it is determined in the flowchart of FIG. 2 that the door is open. Then, the output signal of the photointerrupter 16 is input to the central control unit 19 via the detection circuit 17. At this time, whether a pulse signal is output from the detection circuit 17 or not,
In other words, it is determined whether the blades 14 are blocking the optical axis of the photointerrupter 16 in the flow chart. If the blade 14 happens to be located on the optical axis, it will be determined as "YES" and the flow will proceed.
It is determined whether the tube mounting door is closed. That is, it is determined whether the infusion tube set has been attached to the infusion pump and the tube attachment door has been closed. On the other hand, if the determination is "NO" in the flowchart, the process proceeds to the flowchart, where the central control section 19 outputs a drive signal to the motor pulse generation section 20, and the pulse motor 1
The rotation of the pulse motor 10 continues until the blade 14 interrupts the optical axis of the photointerrupter 16 and the detection circuit 17 outputs a pulse signal. At this time, since the infusion tube set has not yet been attached to the infusion pump, the pumping mechanism 12 is in a so-called idle state. In any case, in FLOHA or FLONI, the pumping mechanism 12 is positioned by the start phase control means of the central control unit 19 at a phase such that the blades 14 interrupt the optical axis of the photointerrupter 16 . Therefore, if the blades 14 are positioned so as to block the optical axis when the pumping mechanism 12 is positioned at a phase corresponding to the time period B where the discharge amount is small as shown in FIG. Starting from a specific position corresponding to the small phase of the pressure sensor 8
will not malfunction.

In this way, once the pumping mechanism 12 is set to a specific position, it is then determined in the flow chamber whether the door is closed or not, in other words, whether or not the infusion tube set has been completely attached to the pump. It is determined whether or not the start key is turned on. When the start key is turned on, the normal pumping operation starts as shown in the float. During this pumping operation, the stop key is constantly monitored as shown in the float, and the stop key is turned on. Then, the pumping operation stops at the flowy, and the flowy returns to repeat the same operation.

In the float, when a drive signal is output from the central control unit 19 and the pulse motor 10 starts to rotate, a series of fingers 12A to 12G move toward the infusion tube 3 as the pulse motor 10 rotates.
is sequentially pressed and closed from the upstream side to the downstream side, and the movement of the tube closing portion pushes out the drug solution in the infusion tube 3 to the downstream side. During the liquid feeding process, any one of the fingers 12A to 12G always closes the infusion tube 3, and as shown in the figure, only when the lowest finger 12G is pressing the infusion tube 3 does the lowest finger 12G close the infusion tube 3 at the same time. The upper finger 12A is also set to block the infusion tube 3. In each cycle, the tube closing portion is connected to the third, fourth, and fifth fingers 12C, 12D, 1
In the process of gradually transitioning to 2E, infusion tube 3
The chemical liquid inside is also sent in accordance with the operation of each finger 12C, 12D, and 12E, so that a discharge pressure is generated, and a corresponding discharge amount can be obtained as in the time period indicated by A in FIG. However, in the process in which the lowest finger moves from the state in which the infusion tube 3 is blocked by 12G to the state in which it is released, the tube blocking portion shifts from the highest finger 12A to the second finger 12B; The volume of the infusion tube 3 from this blocking part to the downstream discharge part increases temporarily and rapidly as the lowest finger 12G separates from the infusion tube 3.
As a result, the discharge pressure decreases, and a period of low discharge volume continues until the third finger 12C begins to block the infusion tube 3, as shown in the time zone B in FIG. Such fluctuations in discharge amount are
This is repeated every cycle of the pumping operation process, that is, every rotation of the pulse motor 10.

On the other hand, since the pulse motor 10, which is the drive source of the pumping mechanism 12, rotates by a fixed minute angle every time one pulse is applied, the number of pulses required to rotate the pulse motor 10 once is constant. Therefore, the pulse counter 18 counts the pulses supplied from the motor pulse generating section 20 to the motor driving section 21, and the pulse counter 18
is reset by the output pulse of the detection circuit 17, which is output once per rotation of the pulse motor 10, so the count signal of the pulse counter 18 is
This corresponds to the phase in one cycle whose origin is the point in time when the detection signal is output from the photointerrupter 16. Therefore, by calculating the count value of the pulse counter 18 by the central control unit 19, the current phase and ejection amount in one cycle can be continuously detected. In this way, the pumping mechanism 1
By being able to continuously detect the current phase in one cycle of 2, in addition to starting the pumping mechanism 12 from a specific phase position as described above, it is also possible to start the pumping mechanism 12 from any phase position depending on the situation. Even more advanced control can be performed. In the above embodiment, a case has been described in which the start position control means is actuated by detecting that the tube attachment door is opened to attach an infusion tube set, but the infusion tube set is removed after the infusion injection operation is completed. Even if the start position control means is actuated by detecting that the tube attachment door is opened to perform initial settings for the next infusion, the same effect as in the above embodiment can be obtained. can get.

FIG. 3 shows another embodiment of the present invention, in which the same parts as in FIG. 1 are given the same reference numerals. The difference from FIG. 1 is that a DC motor 23 is used as the drive source. This DC
The applied voltage for driving the motor 23 is proportional to the number of rotations, and the time required for one rotation is inversely proportional to the applied voltage. Therefore, the central control unit 1
The voltage applied to the DC motor 23 from the motor drive unit 24 driven by the clock pulse generator 2
5 and generates a clock pulse proportional to the voltage applied to the DC motor 22. This clock pulse is counted by a clock pulse counter 26, and this clock pulse counter 26 is transmitted from a photointerrupter 16 to a detection circuit 17.
The count value of the clock pulse counter 26 is reset by the detection pulse outputted via the pumping mechanism 12 during the pumping operation.
The current phase and ejection amount are calculated by the central control unit 19 as in the case of FIG. 1.

FIG. 4 shows still another embodiment of the present invention, in which the same parts as in FIGS. 1 and 3 are given the same reference numerals. A slit disk 27 as a member to be detected is arranged such that a large number of slits 27A are arranged at regular intervals on the same circle on the peripheral edge, and one slit is arranged at a specific position closer to the center than each of these slits 27A. 27B, and this slit disk 27 is fixed concentrically to the motor shaft 11. As detection means for the detected member, a first photointerrupter 28 for detecting each slit 27A on the peripheral edge and a second photointerrupter 29 for detecting a specific slit 27B are provided. The detection signal from the first photointerrupter 28 is counted by the slit counter 30, and the count value of the slit counter 30 is reset by the detection signal from the second photointerrupter 29. Here, since one rotation of the motor 10 corresponds to one cycle of the pumping operation process, the timing at which the second photointerrupter 29 detects the slit 27B coincides with the desired phase in one cycle of the pumping operation process. Once set, the count value of the slit counter 30 corresponds to the current phase in one period whose origin is the phase determined by the detection signal of the second photointerrupter 29. Therefore, the count signal of the slit counter 30 is calculated by the count value determination section 31 to detect the current phase and ejection amount. Moreover, the detection signal of the second photointerrupter 29 is
This signal is input to the central control unit 19 as a positioning signal when starting the infusion pump.

It should be noted that the present invention is not limited only to the above-mentioned embodiments, and it goes without saying that various embodiments are possible without departing from the scope of the claims. for example,
In each of the above embodiments, the motor shaft 11 is directly connected to the pumping mechanism 12 and one revolution of the motors 10, 22 corresponds to one cycle of the pumping operation process. May be connected. Moreover, although the pumping mechanism 12 that uses rotational motion has been described as an example, it goes without saying that the present invention can also be applied to a pumping mechanism that uses linear reciprocating motion.

<Effects of the Invention> As described in detail above, according to the infusion pump of the present invention, a member to be detected is fixed to a region of the pumping mechanism that performs periodic motion, and a means for detecting the member to be detected is provided to control the pumping of the pumping mechanism. A phase detection means is configured to detect a specific phase or an arbitrary phase in one cycle of the operating process, and pumping is performed based on the phase information detected by the phase detection means when the tube set is not connected when the tube set is connected or disconnected. Since the mechanism is configured to be driven until it is positioned at the set phase, the pumping mechanism can be automatically positioned in advance at a specific set phase corresponding to a predetermined discharge amount before installing the tube set, so pressure detection is possible. It is possible to reliably prevent malfunction of the device.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the infusion pump of the present invention, FIG. 2 is a flowchart of FIG. 1, and FIGS. 3 and 4 are block diagrams of another embodiment of the present invention. FIG. 5 is a schematic diagram of an infusion system to which the present invention is applied, and FIG. 6 is a diagram showing the relationship between time and discharge amount of an infusion pump. 11...Motor shaft (portion that performs periodic motion), 12...Pumping mechanism, 14...Blade (detected member), 16, 28, 29...Photointerrupter (detection means), 19...Central control unit ( start position control means), 27... slit plate (detected member).

Claims (1)

[Claims] 1. A pumping mechanism that continuously pumps liquid by repeating a predetermined pumping operation process using rotational motion or linear reciprocating motion as one cycle;
The infusion pump is provided with a pressure detector disposed upstream of the pumping mechanism in the direction of infusion fluid flow and detects the occurrence of a blockage state of the infusion tube based on the internal pressure of the tube, in which the pumping mechanism is periodically moved. a phase detection means for detecting a specific phase or an arbitrary phase in one cycle of the pumping operation process of the pumping mechanism using a detection member fixed to a part so as to be integrally interlocked with the detection member, and a tube set; and a start position control means for driving the pumping mechanism to a set phase based on the phase information of the phase detection means when the tube set is not connected when the tube set is connected or disconnected. infusion pump.