JP2012251460A - Fluid pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid pump that can suppress a change in a transfer amount of fluid over time.SOLUTION: The fluid pump includes: a fluid transfer means 20 that transfers the fluid in an elastic tube in a moving direction of a pressed portion by moving the position pressing the elastic tube 70 along the elastic tube 70; and conductance adjusting means 40 by which a conductance of an elastic tube located downstream in a transfer direction of the fluid with the fluid transfer means is reduced, compared to one of an elastic tube in an opened state.

Description

  The present invention relates to a fluid pump, and more particularly, to a peristaltic infusion pump that feeds liquid by a peristaltic motion of a soft elastic tube. Infusion is a treatment method in which a drug solution is injected into the body from the vein of a patient.

  The infusion pump has a volume control method and a drip control method. Among them, the volume control type infusion pump has a structure in which a dedicated infusion set in which the tube inner diameter is precisely defined is used and the tube is deformed corresponding to the set flow rate and sent. There are a finger pump using a finger (refer to Patent Document 1) and a roller pump using a roller as a method of giving tube deformation.

JP-A-7-116251

  When these pumps are used for long-time infusion, there is a problem in that the tube cross-sectional area is gradually reduced due to a decrease in the restoring force of the tube, and the liquid feeding flow rate is reduced.

  Therefore, a main object of the present invention is to provide a fluid pump that can suppress a change in the amount of fluid transferred over time.

According to the present invention,
A fluid transfer means for transferring a fluid in the elastic tube in a moving direction of the pressing portion by moving a portion pressing the elastic tube along the elastic tube;
Conductance adjusting means for making the conductance of the elastic tube downstream in the fluid transfer direction relative to the fluid transfer means smaller than the conductance of the elastic tube in an open state of the elastic tube;
A fluid pump is provided.

  Preferably, when the fluid is transferred by the fluid transfer means, the conductance adjustment means makes the conductance of the elastic tube on the downstream side smaller than the conductance of the elastic tube in the open state of the elastic tube. And a control means for controlling the fluid transfer means and the conductance adjusting means.

  Preferably, the apparatus further comprises pressure measuring means for measuring an internal pressure of the elastic tube between the fluid transfer means and the conductance adjusting means, and the control means is configured to measure the elastic tube measured by the pressure measuring means. The conductance adjusting means is controlled to adjust the conductance of the elastic tube according to the internal pressure.

  Preferably, the conductance adjusting means is controlled so that the internal pressure of the elastic tube is maintained at a predetermined pressure during the transfer of the fluid by the fluid transferring means.

  Preferably, the predetermined pressure is a pressure within a range of 140 to 290 kPa, and more preferably, the predetermined pressure is a pressure within a range of 220 to 290 kPa.

  Preferably, the conductance adjusting unit includes a pressing unit that presses the elastic tube, and the conductance of the elastic tube is adjusted by adjusting a pressing force applied to the elastic tube by the pressing unit.

  Preferably, the fluid transfer means sequentially moves a plurality of fingers pressing the elastic tube from the upstream side toward the elastic tube, and sequentially moves the fingers pressing the elastic tube from the upstream finger to the downstream side. It is a fluid transfer means which transfers the fluid in the said elastic tube by moving to a finger of this.

  Preferably, the fluid transfer means is a fluid transfer means for transferring a fluid in the elastic tube by moving a roller pressing the elastic tube from the upstream side to the downstream side.

  ADVANTAGE OF THE INVENTION According to this invention, the fluid pump which can suppress the temporal change of the amount of fluid transfer is provided.

FIG. 1 is a diagram for explaining an example of use of an infusion pump according to a preferred embodiment of the present invention. FIG. 2 is a schematic perspective view for explaining an infusion pump according to a preferred embodiment of the present invention. FIG. 3 is a schematic longitudinal sectional view for explaining an infusion pump according to a preferred embodiment of the present invention. FIG. 4 is a schematic perspective view for explaining the finger pump used in the infusion pump according to the preferred embodiment of the present invention. FIG. 5 is a schematic cross-sectional view for explaining the operation of the finger pump used in the infusion pump according to the preferred embodiment of the present invention. FIG. 6 is a schematic longitudinal sectional view for explaining an infusion pump according to a preferred embodiment of the present invention. FIG. 7 is a diagram showing the experimental results of measuring the liquid feeding flow rate every 30 seconds from the pump start to 8 hours. FIG. 8 is a schematic longitudinal sectional view for explaining a roller pump used in an infusion pump according to a preferred embodiment of the present invention. FIG. 9 is a schematic perspective view for explaining an infusion pump of a comparative example. FIG. 9 is a schematic perspective view for explaining an infusion pump of a comparative example.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram for explaining an example of use of an infusion pump according to a preferred embodiment of the present invention. An infusion unit 80 for infusion is attached to a stand 90. The infusion bag 94 is hung on the arm 92 of the stand 90. The infusion pump 10 that feeds the chemical solution that circulates inside the tube 70 connected to the infusion bag 94 is accommodated in the infusion unit 80.

  2 and 3, the infusion pump 10 includes a main body 12 and a lid 14. The main body 12 includes a liquid feeding unit 20, a bubble detection unit 30, a pressure sensor 32, a conductance adjustment unit 40, a blockage detection unit 34, and a clamp 36. A groove 18 for accommodating the tube 70 is provided in the wall surface 16 of the main body 12 in the vertical direction. The tube 70 is mounted in the groove 18 and the lid 14 is closed. The liquid feeding unit 20, the bubble detection unit 30, the pressure sensor 32, the conductance adjustment unit 40, the blockage detection unit 34, and the clamp 36 are also arranged in this order from the upstream side to the downstream side along the groove 18 on the wall surface 16 side of the main body 12. Is provided. The bubble detection unit 30, the blockage detection unit 34, and the clamp 36 are safety mechanisms. Bubbles in the chemical solution in the tube 70 are detected by the bubble detection unit 30. The occlusion detector 34 detects whether the tube 70 is occluded. The clamp 36 prevents the flow of the chemical solution due to free fall when the lid 14 is carelessly opened.

  The liquid feeding section 20 functions as a fluid transfer means for moving the chemical solution in the elastic tube 70 in the moving direction of the pressed portion by moving the portion that presses the elastic tube 70 along the tube 70. In the present embodiment, the liquid feeding unit 20 is a finger pump, which sequentially pushes out the fingers 22 and sequentially closes the tubes 70 to the downstream side.

  4 and 5, when the tube 70 is pressed by the finger 22 against the pressure plate 24 attached to the lid 14 (see FIGS. 2 and 3), the tube 70 at the position pressed by the finger 22 is It is sandwiched between the finger 22 and the pressure plate 24 to be closed. The plurality of fingers 22 are sequentially moved from the upstream side toward the tube 70, and the tubes 22 are sequentially pressed from the upstream side by moving the fingers 22 that press the tube sequentially from the upstream finger to the downstream finger. By sequentially closing 70 from the upstream side, the chemical solution is transferred from the upstream side to the downstream direction. As shown in FIG. 4, the plurality of fingers 22 are operated by a cam 27, and the cam 27 is driven by a motor 29 via a speed reduction mechanism 28.

  The pressure sensor 32 uses a load cell. A tonometry method is used in which a part of the tube 70 is crushed flat and the internal pressure is measured from the outside of the tube.

  The conductance adjusting unit 40 functions as conductance adjusting means for making the conductance of the tube 70 smaller than the conductance of the tube 70 in the open state of the tube 70. In the present embodiment, the conductance adjustment unit 40 includes an occluder 42 and a linear actuator 44 that drives the occluder 42.

  As shown in FIG. 6, the infusion pump 10 includes a control unit 50. The control unit 50 is connected to the linear actuator 44 of the conductance adjustment unit 40, the pressure sensor 32, and the motor 29 of the liquid feeding unit 20, and acquires pressure information from the pressure sensor 32 and drives the linear actuator 44 and the motor 29. Take control.

  The liquid feeding unit 20 of this embodiment is a finger pump, and includes a pressure sensor 32 and an occluder 42 on the downstream side of the finger 22. If the tube 70 is closed with the occluder 42 in a state where the finger 22 is operated and liquid feeding is performed, the conductance of the tube 70 becomes small, and the internal pressure of the tube 70 increases due to flow path resistance. While the internal pressure of the tube 70 is detected by the pressure sensor 32, the pressure closing degree of the tube 70 is controlled by the control unit 50 to maintain the set internal pressure of the tube 70.

  As described above, when the chemical solution is transferred in the tube 70 by the liquid supply unit 20, the control unit 50 causes the conductance of the tube 70 to be smaller than the conductance of the tube 70 in the open state by the occluder 42. The motor 26 of the liquid feeding unit 20 and the linear actuator 44 of the conductance adjusting unit 40 are controlled. At that time, the linear actuator 44 of the conductance adjusting unit 40 is controlled by the control unit 50 in accordance with the internal pressure of the tube 70 measured by the pressure sensor 32, and the conductance of the tube 70 is adjusted by the occluder 42. When the chemical solution is transferred in the tube 70 by the liquid feeding unit 20, the control unit 50 according to the internal pressure of the tube 70 measured by the pressure sensor 32 so as to maintain the internal pressure of the tube 70 at a predetermined pressure. Thus, the linear actuator 44 of the conductance adjusting unit 40 is controlled.

  Since the tube 70 of the liquid feeding section 20 receives the internal pressure and tends to expand greatly, it is possible to prevent the restoring force from being lowered and to prevent the flow rate from being lowered even when used for a long time.

  The reason why the bubble detection unit 30 is installed downstream of the liquid feeding unit 20 is that a better effect can be obtained by making the gap between the finger lower end of the liquid feeding unit 20 and the occluder 42 as much as possible.

  In addition, a predetermined pressure is applied to the occluder 42 by the linear actuator 44, but the internal pressure is not applied to the tube 70 before the infusion, so the occluder 42 is completely closed. When the finger 22 is operated, the internal pressure of the tube 70 increases, and when the set pressure is reached, the occluder 42 opens slightly and starts liquid feeding.

  In this case, since there is a time delay from the start of the pump to the start of the infusion, it is desirable that the finger 22 be fast-forwarded immediately after the start until the pressure increases.

  FIG. 7 is a diagram showing the experimental results of measuring the liquid feeding flow rate every 30 seconds from the pump start to 8 hours. As shown in FIGS. 9 and 10, 0 kPa indicates a comparative example in which the pressure sensor 32 and the conductance adjusting unit 40 are not used. In this case, the flow rate of about 0.9 mL / h decreases in 8 hours. The internal pressure of the tube 70 has an effect of preventing a decrease in flow rate from 140 kPa. At 290 kPa, the decrease after 8 hours was 0.2 mL / h. Furthermore, when the internal pressure of the tube 70 was increased and set to 300 kPa, a reverse flow or the like in the liquid feeding unit 20 including the fingers 22 was generated, and the effect was reduced. Accordingly, the set internal pressure of the tube 70 is 140 to 290 kPa, and an effect of preventing a decrease in the flow rate is obtained, and more preferably 220 to 290 kPa, a more effective effect is obtained.

  FIG. 8 is a schematic longitudinal sectional view for explaining a roller pump used in the infusion pump 10 according to a preferred embodiment of the present invention. Up to now, the case where a finger pump is used for the liquid feeding unit 20 has been shown. However, the infusion pump 10 according to a preferred embodiment of the present invention is a case where a roller pump is used for the liquid feeding unit 20 instead of the finger pump. Is also applicable. The roller pump is a peristaltic pump of the type in which the tube 70 is squeezed by the roller 64 instead of the finger 22 of the finger pump and fed. In this roller pump, the roller 64 pressing the elastic tube 70 is moved from the upstream side to the downstream side, so that the portion of the tube 70 that is sandwiched between the pump head 66 and the roller 64 is closed upstream. It is the fluid transfer means which moves the chemical | medical solution in the tube 70 by moving to the downstream side. The rollers 64 are respectively mounted in the vicinity of three apexes of the equilateral triangular roller mounting plate 62, and the roller mounting plate 62 is driven by a control unit (not shown) to drive a motor or the like (not shown). The roller 64 moves from the upstream side to the downstream side.

  The present invention is suitable for foods that require a constant flow rate and chemical feed pumps. Furthermore, it is optimal to apply as an infusion pump for infusion therapy that requires infusion at an accurate flow rate.

  While various typical embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Accordingly, the scope of the invention is limited only by the following claims.

DESCRIPTION OF SYMBOLS 10 Infusion pump 12 Main body 14 Lid 16 Wall surface 18 Groove 20 Liquid sending part 22 Finger 24 Pressure plate 27 Cam 28 Deceleration mechanism 29 Motor 30 Bubble detection part 32 Pressure sensor 34 Blocking detection part 36 Clamp 40 Conductance adjustment part 42 Occluder 44 Linear actuator 50 Control unit 70 Tube

Claims (9)

A fluid transfer means for transferring a fluid in the elastic tube in a moving direction of the pressing portion by moving a portion pressing the elastic tube along the elastic tube;
Conductance adjusting means for making the conductance of the elastic tube downstream in the fluid transfer direction relative to the fluid transfer means smaller than the conductance of the elastic tube in an open state of the elastic tube;
A fluid pump comprising:   When the fluid is transferred by the fluid transfer means, the conductance adjusting means makes the conductance of the elastic tube on the downstream side smaller than the conductance of the elastic tube in an open state of the elastic tube. 2. The fluid pump according to claim 1, further comprising control means for controlling the transfer means and the conductance adjusting means.   Pressure measuring means for measuring an internal pressure of the elastic tube between the fluid transfer means and the conductance adjusting means is further provided, and the control means is configured to measure the internal pressure of the elastic tube measured by the pressure measuring means. 3. The fluid pump according to claim 2, wherein the conductance adjusting means is controlled so as to adjust the conductance of the elastic tube.   The fluid pump according to claim 3, wherein the conductance adjusting means is controlled so as to maintain an internal pressure of the elastic tube at a predetermined pressure during the transfer of the fluid by the fluid transferring means.   The fluid pump according to claim 4, wherein the predetermined pressure is a pressure within a range of 140 to 290 kPa.   The fluid pump according to claim 5, wherein the predetermined pressure is a pressure within a range of 220 to 290 kPa.   The conductance adjusting unit includes a pressing unit that presses the elastic tube, and the conductance of the elastic tube is adjusted by adjusting a pressing force applied to the elastic tube by the pressing unit. The fluid pump according to item 1.   The fluid transfer means sequentially moves a plurality of fingers pressing the elastic tube from the upstream side toward the elastic tube, and sequentially moves the fingers pressing the elastic tube from the upstream finger to the downstream finger. The fluid pump according to claim 1, wherein the fluid pump is a fluid transfer means for transferring the fluid in the elastic tube.   The fluid transfer means is a fluid transfer means for transferring a fluid in the elastic tube by moving a roller pressing the elastic tube from the upstream side to the downstream side. The fluid pump described in 1.