JP2645760B2 - Infusion method and infusion pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an infusion method and an infusion pump for sending a liquid in an infusion tube at a constant flow rate.

(Prior art) Conventionally, several types of pumps used for infusion are known. However, a peristaltic infusion pump is excellent in that it does not damage the delivery tube even after performing infusion for a long time. This type of pump is mainly used.

The peristaltic infusion pump is configured such that a holding plate and a plurality of parallel liquid feeding fingers are opposed to each other so as to sandwich a liquid feeding tube (for example, Japanese Patent Publication No.
The operation of sequentially moving the closing point of the liquid feed tube by the liquid feed finger and the holding plate from the suction side to the discharge side of the liquid feed tube is repeatedly performed.

(Problem to be Solved by the Invention) The peristaltic infusion pump crushes (closes) a liquid-feeding tube having a circular cross section by a liquid-feeding finger and a holding plate, and moves the crushed position from the suction side to the discharge side. The principle is that the liquid in the liquid feeding tube is transferred by sequentially moving the liquid to the liquid feeding tube. Therefore, when the closing point moves from the suction side to the discharge side and returns to the suction side again, the pressure for transferring the liquid temporarily disappears, and there is a problem that a pulsating flow occurs in the infusion.

In addition, the liquid sending tube is a tube whose natural shape is a circular section, and between a liquid sending finger and a holding plate, a circular section and a completely crushed flat state.
The closing and opening were repeatedly performed.

Accordingly, the relationship between the operation of one liquid feeding finger and the amount of liquid extruded by the liquid feeding finger is as shown by the curve a in FIG. As a result, there is also a problem that a pulsating flow occurs in the infusion in a process in which the operation of the liquid feeding finger shifts to the adjacent liquid feeding finger.

Further, the liquid feeding tube has such a property that the return to the perfect circular shape is gradually impaired while the closing and opening operations are repeatedly performed by the operation of the liquid feeding finger. Therefore, the amount of liquid transferred by one operation of the liquid feeding finger gradually decreases while the infusion is continued, and tends to be in a steady state soon, and becomes stable from the start to the end of the infusion. There was also a problem that it was difficult to obtain a flow rate.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an infusion method and an infusion pump having a small pulse flow. Another object of the present invention is to provide an infusion method and an infusion pump capable of performing infusion at a stable flow rate from the start to the end of infusion.

(Means for Solving the Problems) In the present invention for achieving the above object, when the closing point moves to the discharge side end, a closing point is also formed on the suction side, and the pressure of the discharge side end is reduced. Until the closing point is opened, the liquid in the liquid transfer tube that is trapped between the two pressure closing points is pressurized to push open the pressure closing point on the discharge side and to release one of the trapped liquid. Part is discharged to the discharge side.

Therefore, the infusion pump of the present invention synchronizes the operations of the plurality of delivery fingers on the discharge side and the plurality of delivery fingers on the suction side of the peristaltic infusion pump as described above. Further, the synchronized holding plate opposing the plurality of liquid feeding fingers on the discharge side elastically weakens more than the part of the holding plate opposing the plurality of liquid feeding fingers on the suction side, and the synchronized ejection side closer to the discharge side. Several liquid feed fins closer to the suction side than the plural liquid feed fingers are formed to have a large thickness.

Further, in order to prevent a pulsating flow caused by the deformation of the liquid feeding tube by the liquid feeding finger and to prevent the flow rate of the liquid feeding from changing from the start to the end of the infusion, the present invention In the infusion method of (1), the deformation of the feed tube by the feed finger is repeated between a completely crushed state and a slightly flattened state. For this reason, in the infusion pump according to the present invention, the permeation pump of the peristaltic infusion pump has a pumping action between a completely crushed state and a slightly flattened state by the action of the liquid feeding finger. Configuration.

(Function) As described above, according to the infusion method and the infusion pump of the present invention, when the closed position of the liquid sending finger returns from the discharge side to the suction side, the state where the pressure for transferring the liquid temporarily disappears is eliminated. be able to.

Also, the pumping action between the completely squashed state and the slightly flattened state of the liquid feeding tube allows the flow rate to be smaller than the operation of the liquid feeding finger in the curve a in FIG. Is not used for liquid transfer,
As a result, a pulsating flow can be prevented. Further, the return state of the liquid sending tube can be made constant from the start to the end of the liquid sending, and the flow rate can be made constant.

(Embodiment) Fig. 1 shows a main part of a peristaltic infusion pump according to an embodiment, in which a liquid feeding tube 1 has two holding plates 2a, 2b and 14 liquid feeding fingers 3a, 3b ... 3n.

The holding plate 2a is held by the fixing member 4 by a spring 5a, and the holding plate 2b is held by a spring 5b having a lower elasticity than the spring 5a.

On the other hand, the liquid feeding fingers 3a, 3b.
8n are attached to the rotating shaft 7 which is supported by the rotary shaft 7 via the eccentric cams 8a, 8b... 8n, and the liquid feeding fingers 3a, 3b. The difference is given. Therefore, the liquid sending fingers 3a and 3m, and 3b and 3n operate in synchronization with each other. The thickness of each of the liquid feeding fingers 3a, 3b,..., 3n is the same as the liquid feeding fingers 3a, 3b, 3g, 3h except for the third liquid feeding finger 3c from the left in the figure to the sixth liquid feeding finger 3f. .. 3n have the same thickness, while the third liquid feeding finger 3c to the sixth liquid feeding finger 3f are twice as thick as the other liquid feeding fingers 3a, 3b. In addition, this liquid sending finger 3c-3f
Can be configured to have the same thickness as the other liquid feeding fingers 3a, 3b,.

In the above embodiment, when the rotating shaft 7 is rotated, the liquid feeding fingers 3a and 3m, 3b and 3n, 3c... 3l sequentially operate to cooperate with the holding plates 2a and 2b to close and close the liquid feeding tube 1. Therefore, the liquid in the liquid feed tube 1 is transferred in the direction of arrow 9. Accordingly, a pump action can be obtained in the liquid feeding tube 1 with A being the suction side and B being the discharge side.

FIG. 2 is a chart in which the flow rate of the liquid sent by the infusion pump of the embodiment is analyzed.
The liquid feeding fingers 3a, 3b... 3n are shown alongside, and the positions of the tips of the liquid feeding fingers 3a, 3b. Therefore, for each phase angle, the unhatched portion corresponds to the state in which the liquid is trapped in the liquid sending tube 1, and the number shown in the portion indicates the volume of the trapped liquid (arbitrary). Unit).

When the phase angle is 0 °, the liquid feed tube 1 is filled with 10.5 liquid in the range of the liquid feed fingers 3d to 3l.
With this state as an initial condition, when the rotating shaft 7 is driven, liquid is transferred as follows.

In the step of changing the transfer angle from 0 ° to 30 °, the liquid of 10.5 trapped in the range of the liquid feed fingers 3d to 3l moves to the range of the liquid feed fingers 3l to 3m. Liquid feed finger 3l
Since the volume in the range of 33 m is 9.5, the liquid of 10.5−9.5 = 1 needs to be discharged to the outside. For this discharge, the spring 2b of the holding plate 2b opposed to the liquid sending fingers 3l to 3n has a weaker elasticity than the other spring 2a, and the liquid of volume 1 to be discharged is the liquid sending finger 3n and the holding plate. The closing point of 2b is pushed open and discharged to the discharge side B, that is, transferred. In FIG. 2, the column of OF represents the volume of liquid transferred by pushing and closing the closing point in this way.

Next, in the step of changing the transfer angle from 30 ° to 60 °, the 9.5 liquid trapped in the range of the liquid feed fingers 3e to 3m moves to the range of the liquid feed fingers 3f to 3n. Since the volume in the range of the liquid sending fingers 3f to 3m is 8.5, a liquid of 9.5−8.5 = 1 is discharged, that is, transferred to the discharge side B. In this case, the discharge side B is opened and the closed point no longer exists, so that normal transfer is performed. In FIG. 2, the column of PF indicates the volume of the liquid sent by such normal transfer. Phase angle from 60 ° to 90 °, 120 °, 1
In the process of changing from 50 °, 180 °, 210 °, 240 °, 270 °, and 300 °, as shown in the drawing, there is no closing point on the discharge side of the liquid feeding tube 1, and The liquid sequentially moves to the discharge side, and the volume in the range from the closing point to the liquid sending finger 3n is sequentially reduced by one, and the liquid having the volume of 1 is transferred at every angle of 30 °. That is, the columns of P and F are 1 respectively.

When the transfer angle reaches 300 °, the liquid feed finger 3a closes the liquid feed tube 1, and between this closed position and the closed position moved to the discharge side, that is, the liquid feed finger is closed.
Between 3b and 3j, a volume of liquid of 12 becomes full.

In the step in which the phase angle changes from 300 ° to 330 °, the liquid having a volume of 0.5 at the liquid feeding finger 3n receives normal liquid feeding, and the volume between the closing points is 12 to 11.5.
, The liquid having a volume of 0.5
l, 3m pressure closing point is pushed open and transferred to the discharge side. Therefore, a total volume of 1 is transferred, which is the volume 0.5 by the normal transfer (PF) and the volume 0.5 transferred (OF) by pushing and closing the closing point.

In the process in which the transfer angle changes from 330 ° to 360 °, the volume between the closing points changes from 11.5 to 10.5, and the change is volume 1
Is pushed to open the pressure closing point by the liquid sending filters 3m and 3n, and is transferred to the discharge side.

As described above, in the infusion pump according to the embodiment, during one cycle of operation of the liquid feeding finger, the liquid having a volume of 1 can be transferred at every phase angle of 30 °.
There is no loss of liquid sending pressure. Therefore, it is possible to transfer a fixed amount without generating a pulsating flow.

In the above-described embodiment, the pressing plate is separated into two pressing plates 2a and 2b, and a spring 5b elastically holding the pressing plate 2b on the discharge side.
Has a lower elasticity than the spring 5a holding the holding plate 2a. However, as shown in FIG. 3, one holding plate 2 is held by the U-shaped spring 5, and the discharging side B is moved from the suction side A to the discharging side B. , The repulsive force may gradually decrease.

Next, in the above embodiment, the relationship between the liquid sending tube 1 and the liquid sending fingers 3a, 3b,... 3n is such that the liquid sending tube 1 is completely crushed as shown in FIG. The movement stroke of the liquid feed fingers 3a, 3b... 3n is limited so that compression and release are repeated between a closed state) and a state where the liquid supply fingers 3a, 3b,. It is. That is, although the liquid sending tube 1 is originally a tube having a cross section of a substantially perfect circular state, it is restricted to restore the natural state.

 This is due to the following two reasons.

The first reason is to prevent the so-called trumpet effect. The trumpet effect is caused by the fact that the restored shape of the liquid sending tube 1 changes with the passage of time of the liquid sending. As shown in FIG. 5, the liquid pushed out by one liquid sending finger is generated as shown in FIG. This is a phenomenon in which the flow rate changes like the shape of the tip of a trumpet with the elapse of the time of liquid feeding. This is because, if the liquid sending tube is restored to a substantially circular cross section, it becomes difficult to restore the initial complete state with the elapse of the liquid sending time, and the volume in the liquid sending tube is accordingly adjusted. It happens to decrease. The figure shows the cross-sectional shape of the liquid supply tube at the time of restoration.

In the embodiment, as described above, the restored shape of the liquid supply tube is limited to a state in which the liquid supply tube is slightly flattened as shown in FIG. 4 (b). can do. Therefore, it is possible to secure the transfer at a constant flow rate for a long time from the start of the liquid sending.

The restoring shape of the liquid sending tube 1 is limited by the operation stroke of the liquid sending fingers 3a, 3b,..., And as shown in FIG.
10 can be provided.

 Next, the second reason will be described.

The flow rate obtained when the liquid supply tube 1 is changed from a substantially circular cross section to a state of being completely crushed by one liquid supply finger 3 is as shown by a curve a in FIG.
That is, in the initial stage of the crushing, the flow rate increases only slightly compared to the operation stroke of the liquid feed finger 3. A plurality of liquid feeding fingers are connected with a certain phase difference (eg,
30 °), the sum of the curves a in FIG. 7 becomes the total flow rate.
As a result, a large pulsating flow is generated due to a change in the stroke of the liquid feeding finger 3.

In this regard, when the restored shape of the liquid feeding tube 1 is limited to a slightly flattened state as in the embodiment, the relationship between the crushing of the liquid feeding tube 1 by the liquid feeding finger 3 and the flow rate is represented by a curve in FIG. As a result, the change in the flow rate by the plurality of liquid feeding fingers is as shown by the curve b in FIG. 8, and the pulsating flow can be reduced.

(Effects of the Invention) As described above, according to the present invention, even when the closing point returns from the discharge side to the suction side, the transfer can be performed at a constant flow rate, so that an infusion pump without a pulsating flow can be provided. There is.

In addition, the liquid feeding tube is restored to a state where it is slightly flattened and is not restored to a completely circular shape, so that the so-called trumpet effect is eliminated, and it is possible to transfer a fixed amount over a long time. In addition, there is an effect that it is possible to provide an infusion pump in which a pulsating flow generated when the closing point is moved by the liquid feeding finger is reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an essential part of an infusion pump according to an embodiment of the present invention, FIG. 2 is a chart illustrating the operation of the infusion pump according to the embodiment, FIG. FIGS. 4 (a) and 4 (b) are diagrams for explaining the deformation of the liquid feeding tube in the embodiment of the present invention, FIG. 5 is a graph showing the relationship between the liquid feeding time and the liquid feeding flow rate, and FIG. FIG. 7 is an explanatory view of another embodiment for restricting restoration of a tube, FIG. 7 is a graph showing a relationship between a phase angle and a flow rate of a conventional infusion pump, and FIG. It is a graph which shows a flow rate. 1 ... Liquid feeding tube 2, 2a, 2b ... Holding plate 3a, 3b, 3n ... Liquid feeding finger 5, 5a, 5b ... Spring 7 ... Rotating shaft 8a, 8b, 8n ... Eccentric cam 10 ...... Control members

Claims (11)

(57) [Claims] The liquid in the liquid feed tube is sent by repeatedly moving a closing point formed in the liquid feed tube from the suction side to the discharge side by a plurality of liquid feed fingers opposed to the liquid feed tube. In the liquid infusion method, when the closing point moves to the discharge side end, a closing point is also formed on the suction side, and the two closing points are closed until the closing point of the discharge side end is released. By pressurizing the liquid in the liquid transfer tube trapped between the points, the pressure closing point on the discharge side is pushed open, and a part of the trapped liquid is discharged to the discharge side. Infusion method 2. The infusion method according to claim 1, wherein the closing point of the liquid feeding tube is formed by one or more liquid feeding fingers among a plurality of liquid feeding fingers arranged in parallel. 3. The infusion method according to claim 1, wherein the pressurization of the liquid in the liquid feeding tube trapped between the closing points is performed by a liquid feeding finger between the closing points. 4. In a peristaltic infusion pump in which a holding plate and a plurality of parallel liquid feeding fingers are opposed to each other to sandwich a liquid feeding tube, a plurality of liquid feeding fingers on a discharge side and a plurality of liquid suction fingers on a suction side are provided. The operation of the liquid feeding fingers is synchronized, and the synchronized holding plate facing the plurality of liquid feeding fingers on the discharge side is more elastically held than the portion of the holding plate facing the plurality of liquid feeding fingers on the suction side. In addition, the thickness of several liquid feeding fingers near the suction side adjacent to the liquid feeding fingers near the discharge side is formed larger than the thickness of the plurality of liquid feeding fingers near the synchronized discharge side. Characteristic infusion pump 5. Fourteen liquid feeding fingers are arranged in parallel.
5. The infusion pump according to claim 4, wherein the third to sixth liquid feeding fingers from the suction side are twice as thick as the other liquid feeding fingers, wherein the liquid feeding tube is configured to act on the liquid feeding tube with a phase difference of 30 °. 6. The infusion pump according to claim 4, wherein the holding plate is held by one or two springs. 7. The liquid feeding finger formed to be thicker than the other liquid feeding fingers and having the same thickness as that of the other liquid feeding fingers and comprising a plurality of sheets. Infusion pump 8. The infusion pump according to claim 4, wherein the liquid feeding finger reciprocates between a position where the liquid feeding tube is completely crushed and a position where the liquid feeding tube is slightly flattened. 9. The infusion pump according to claim 4, wherein a member for restricting restoration of the liquid feeding tube is provided within a range of the reciprocating operation of the liquid feeding finger. 10. The liquid in the liquid feed tube is sent by repeatedly moving the closing point formed in the liquid feed tube from the suction side to the discharge side by a plurality of liquid feed fingers provided opposite the liquid feed tube. In the liquid infusion method, when the closing point moves to the discharge side end, a closing point is also formed on the suction side, and the two closing points are closed until the closing point of the discharge side end is released. By pressurizing the liquid in the liquid transfer tube trapped between the points, the pressure closing point on the discharge side is pushed open, so that a part of the trapped liquid is discharged to the discharge side, and An infusion method characterized in that the deformation of the liquid sending tube by the liquid sending finger is repeated between a completely crushed state and a slightly flat state. 11. A peristaltic infusion pump in which a holding plate and a plurality of parallel liquid feeding fingers are opposed to each other so as to sandwich a liquid feeding tube. The operation of the liquid feeding fingers is synchronized, and the synchronized holding plate facing the plurality of liquid feeding fingers on the discharge side is more elastically held than the portion of the holding plate facing the plurality of liquid feeding fingers on the suction side. And the thickness of the liquid feeding fingers closer to the suction side adjacent to the liquid feeding fingers closer to the discharge side is formed larger than the thickness of the plurality of liquid feeding fingers closer to the discharge side synchronized with each other, And an infusion pump, wherein the liquid sending tube receives a pump action between a state in which the liquid sending finger is completely crushed by the action of the liquid sending finger and a slightly flat state.