JPH0467870A - Liquid transportation pump - Google Patents

Abstract

PURPOSE:To correct a pulsating current at the downstream side of a correction mechanism by providing the correction mechanism which controls a tube inner volume extending over the required interval of a liquid transportation tube at the downstream side than a part pressed and closed by a tube pressing body. CONSTITUTION:The correction mechanism 8 which corrects the pulsating current is provided to reduce the pulsating current in a liquid transportation pump as possible by controlling the tube inner volume extending over the required interval of the liquid transportation tube 7 at the downstream side than the part pressed by finger 4 at the most downstream side. In the correction mechanism 8, the pulsating current can be corrected by absorbing a flow rate sent from an upstream side, when it being high, at the required interval by increasing the tube inner volume by opening the liquid transportation tube 7 at the required interval, and when it being low, increasing the flow rate by sending transportation liquid at the required interval.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an infusion pump used in the medical field.

<Prior Art> FIG. 5 is a perspective view showing the configuration of a conventional infusion pump.

In the figure, l is a drive motor, 21 to 28 are a plurality of eccentric cams fixedly attached to the drive shaft 3,
These eccentric cams 21-2. is attached to the drive shaft 3 in a state in which the angle in the rotation direction is sequentially displaced by a predetermined angle. 48 to 46 are each eccentric cam 2
The eccentric cams 2. ~
A finger 28 sequentially presses the infusion tube 7 from the upstream side to the downstream side by rotation, and 6 is a backing plate that supports the infusion tube 7 pressed by the fingers 41 to 48.

In the infusion pump having such a configuration, the rotation of the drive motor l causes an eccentric cam 2. ~2. rotates,
As a result, as shown in the side sectional view of FIG. 6, the fingers 41 to 48 sequentially press and close the infusion tube 7 from the finger 4 located on the upstream side to the finger 4B located on the downstream side, thereby injecting the infusion. The tube is peristalized to send the infusion fluid inside from upstream to downstream.

<Problems to be Solved by the Invention> However, in such a linear peristaltic type conventional infusion pump, when the most downstream finger 48 presses and obstructs the infusion tube 7, infusion is not performed, etc. There is a problem in that the flow rate changes with the flow rate, ie, so-called pulsating flow occurs.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to reduce pulsating flow in an infusion pump as much as possible.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention includes a plurality of eccentric cams that are successively attached along the axis of a rotationally driven drive shaft, and each of the eccentric cams. A plurality of tube pressing bodies are provided on the outer periphery and reciprocate in a direction perpendicular to the axis in conjunction with each eccentric cam, and the tube pressing body moves the infusion by rotation of the eccentric cam as the drive shaft rotates. In an infusion pump that performs a liquid feeding operation by sequentially pressing and closing a tube from an upstream side to a downstream side, the tube pressing body increases or decreases the internal volume of the tube over a required section of the infusion tube downstream of the portion that is pressed and closed. Accordingly, a correction mechanism is provided for correcting the pulsating flow caused by the liquid feeding operation.

Effects> According to the above configuration, since the correction mechanism is provided to increase or decrease the volume inside the tube over a required section of the infusion tube downstream of the portion pressed and occluded by the tube pressing body, for example, the tube pressing body When the flow rate sent by the tube presser is large, the volume inside the tube is increased to absorb the flow rate in the required section, and conversely, when the flow rate sent by the tube presser is small, the volume inside the tube is decreased. The pulsating flow can be corrected by sending out the infusion fluid in the required section and increasing the flow rate.

<Examples> Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a perspective view of one embodiment of the present invention, and FIG. 2 is a side sectional view thereof, and parts corresponding to the above-mentioned conventional example are given the same reference numerals.

In these figures, 1 is a drive motor, 2. 21 are a plurality of (eight in this embodiment) eccentric cams fixedly attached to the drive shaft 3, and these eccentric cams 2.
28 are attached to the drive shaft 3 in a state in which the attachment angles in the rotational direction are sequentially displaced by a predetermined angle. 4, - 48 are respectively disposed on the outer periphery of each of the eccentric cams 21 - 28 and act as tube pressing bodies that reciprocate in a direction perpendicular to the axis 5 of the drive shaft 3 in conjunction with the rotation of the eccentric cams 21 - 28; 6 is a backing plate that supports the infusion tube 7 pressed by the fingers 48-48.

In this infusion pump, rotation of a drive motor l causes an eccentric cam 2. 28 rotates, and as a result, as shown in the side view of FIG. 2, the fingers 48 to 48 sequentially press and close the infusion tube 7 from the finger 4I located on the upstream side to the sulfinger 4e located on the downstream side. The infusion tube 7 is peristalized to perform a liquid feeding operation in which the infusion liquid inside is sent from the upstream side to the downstream side.

The above configuration is similar to the conventional example described above.

In this embodiment, in order to reduce the pulsating flow in the infusion pump as much as possible, the volume inside the tube is increased or decreased over a required section of the infusion tube 7 further downstream than the part pressed by the most downstream finger 48. A correction mechanism 8 for correcting pulsating flow is provided.

The correction mechanism 8 includes an eccentric cam 9 fixedly attached to the drive shaft 3 and a direction perpendicular to the axis 5 of the drive shaft 3 that is arranged on the outer periphery of the eccentric cam 9 and rotates in conjunction with the rotation of the eccentric cam 9. It is composed of a correction finger IO that increases or decreases the internal volume of the tube over a required section by reciprocating.

The shapes and mounting positions of the correction finger 10 and the eccentric cam 9 in this embodiment are as follows.

The diameter of the eccentric cam 9 and the angle at which it is attached to the drive shaft 3 are such that when the correction finger IO moves forward most toward the infusion tube 7 and presses it, it moves to the point where it closes the infusion tube 7, and vice versa. When moving backward, the other fingers 41 to 48
It is set to move to the same position as .

In this embodiment, in order to most effectively correct pulsating flow as described below, the mounting angle is approximately the same as that of the second finger 48 from the upstream side, and the second finger 42 When the infusion tube 7 is pressed and occluded, the correction finger IO presses the infusion tube 7 just before it is occluded, and when the second fin force 48 retreats and opens the infusion tube 7, the correction finger IO 10 is also moved back to open the infusion tube 7.

Further, the planar shape of the correction finger 10 is basically the same as the other fingers 4□ to 48, and the thickness of this correction finger IO is set so that it can press the infusion tube 7 over a required section. ing.

This required section is set to a size that allows the change in flow rate required for correction of pulsating flow to be obtained by increasing or decreasing the volume inside the tube.

In the correction mechanism 8 having the above configuration, when the flow rate sent from upstream is large, the infusion tube 7 in the required section
By opening the infusion tube 7 and increasing the volume inside the tube, the flow rate is absorbed in the required section, and conversely, when the flow rate sent is small, by pressing the infusion tube 7 in the required section and reducing the volume inside the tube. The pulsating flow is corrected by sending out the infusion fluid in the required section and increasing the flow rate.

Next, the pulsating flow correction operation by the correction mechanism of the present invention will be explained in detail.

The solid line in FIG. 3 shows the change in flow rate when no correction is performed by the correction mechanism 8, that is, in the conventional example. This third
In the figure, the horizontal axis shows elapsed time, and the vertical axis shows flow rate. Note that the horizontal axis also shows numbers 1 to 8 of the fingers 4 and 48 that press and close the infusion tube 7 at that time.

As shown by the solid line in FIG. 3, the most downstream fin tf4
8h<When the infusion tube 7 is pressed and occluded, the flow rate is 0.
Then, the flow rate increases gradually, reaches a maximum when the fourth finger 44 from the upstream presses and closes the infusion tube 7, and then gradually decreases, creating a pulsating flow.

FIG. 4 is a diagram showing changes in the tip position of the correction finger 10 over time, the horizontal axis corresponds to FIG. 3, and the vertical axis shows the tip position of the correction finger. .

In FIG. 3, the flow rate sent from the time when the third finger 4 from the upstream presses and closes the infusion tube 7 to the time when the next finger 44 presses and closes the infusion tube 7 corresponds to the shaded area A.

On the other hand, at this time, the correction finger lo will retreat from point B to point C, as shown in Fig. 3, and as a result, the increase in the volume within the tube over the required section will be qualitatively reduced by the diagonal line. It can be considered that it roughly corresponds to the part.

Therefore, the flow rate sent to the downstream side of the correction mechanism 8 is the flow rate shown by the shaded area A in FIG. 3 minus the increase in the tube internal volume shown by the shaded area in FIG. 4.

Conversely, in FIG. 3, the flow rate sent from the time when the sixth finger 411 from the upstream presses and closes the infusion tube 7 to the time when the next finger 47 presses and closes the infusion tube 7 is the shaded area E. corresponds to

On the other hand, at this time, the correction finger IO advances from point F to point G and presses the infusion tube 7, as shown in FIG. 4, thereby reducing the volume within the tube over the required section. Qualitatively, the decrease can be considered to roughly correspond to the shaded area H, and the infusion will be sent downstream by this decreased volume.

Therefore, the flow rate sent to the downstream side of the correction mechanism 8 is the flow rate shown by the shaded area E in FIG. 3 plus the decrease in the tube internal volume shown by the shaded area H in FIG. This is the sum of the flow rate sent out from

Therefore, when the increase/decrease in the tube internal volume due to the correction mechanism 8 is represented in FIG. 3, it is shown by a broken line. The reduction in the volume inside the tube is the maximum,
Thereafter, the decrease becomes smaller, and when the second finger 42 from the upstream presses and closes the infusion tube 7, there is no change in increase or decrease, and then the increase increases, and the fourth finger 44 from the upstream presses the infusion tube 7. During occlusion, the increase reaches a maximum and then decreases.

Therefore, the shaded area H in FIG.
In the figure, they are represented by shaded areas I and J, respectively.

Therefore, the flow rate shown by the solid line in FIG. The flow rate becomes approximately constant, as shown by the imaginary line in FIG. 3, and the pulsating flow is corrected.

<Effects of the Invention> As described above, according to the present invention, a correction mechanism is provided that increases or decreases the internal volume of the tube over a required section of the infusion tube downstream of the portion pressed and occluded by the tube pressing body. For example, when the flow rate sent by the tube pusher is large, the internal volume of the tube is increased to absorb the flow rate in the required section, and conversely, when the flow rate sent by the tube pusher is small, the tube The pulsating flow is corrected on the downstream side of the correction mechanism by reducing the internal volume and delivering the transfusion in the required section to increase the flow rate.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is a side sectional view of FIG. 1, FIG. 3 is a diagram showing changes in flow rate, and FIG. 4 is a diagram showing changes in the tip position of the correction finger. 5 is a perspective view of a conventional example, and FIG. 6 is a side sectional view of FIG. 5. 21-28... Eccentric cam, 3... Drive shaft, 48-48
...Finger, 7...Infusion tube, 8...Correction mechanism.

Claims (1)

[Claims] (1) A plurality of eccentric cams (2_1 to 2
_8), and a plurality of tube pressing bodies () which are provided on the outer periphery of each of the eccentric cams (2_1 to 2_8) and reciprocate in a direction perpendicular to the axis (3) in conjunction with each of the eccentric cams (2_1 to 2_8). 4_1 to 4_8), and the eccentric cam (2_1 to 2_8) accompanying the rotation of the drive shaft (3).
In an infusion pump in which the tube pressing bodies (4_1 to 4_8) sequentially press and close the infusion tube (7) from the upstream side to the downstream side to perform a liquid feeding operation, the tube pressing bodies (4_1 to 4_8) press A correction mechanism (8) is provided that corrects the pulsating flow caused by the liquid feeding operation by increasing/decreasing the volume inside the tube over a required section of the infusion tube (7) downstream of the occluded part. Infusion pump.