Peristaltic pump and method of transporting material with a peristaltic pump

Abstract

A peristaltic pump comprises a tube to transport a material in a transport direction and one or more piezoelements, which are configured to cause a squeezing of the tube. Furthermore, a method of transporting material comprises the step of successively actuating the piezoelements along the transport direction of the material and thereby causing a squeezing of the tube.

Claims

1. A peristaltic pump, comprising: a tube to transport a material in a transport direction; a plurality of piezoelements arranged in a row along the tube, the plurality of piezoelements being configured to expand when they are actuated to cause a squeezing of the tube; a holder having an expansion end and a blocking end, at least one of the plurality of piezoelements being held by the holder, the holder being configured to permit each held piezoelement to expand along an expansion direction toward the expansion end of the holder and configured to block movement of the piezoelement at the blocking end of the holder when the piezoelement is expanding; and a plurality of levers, each lever being arranged between a corresponding at least one of the piezoelements and the tube, and each lever having a rotation axis located at a first end of the lever, a second end that is at an opposite longitudinal end of the lever from the first end, and a contact area being configured to interact with the corresponding at least one of the piezoelements, the contact area of the lever being closer to the rotation axis of the lever than to the second end of the lever; wherein an expansion of the corresponding at least one of the piezoelements causes a tangential displacement of the corresponding contact area about the rotation axis of the lever, that in turn causes a movement of the lever; and wherein each lever is configured to contact the tube at a location at the second end of the lever that is further from the rotation axis of the lever than the contact area is from the rotation axis of the lever.

2. The peristaltic pump of claim 1, further comprising a lever spring that is configured to pretension at least one of the levers in a direction that is opposed to a direction of movement of the lever caused by the expansion of at least one of the piezoelements.

3. The peristaltic pump of claim 1, further comprising a main body and an exchange part configured to be attachable to the main body.

4. The peristaltic pump of claim 3, wherein the exchange part comprises a tube guide for guiding the tube.

5. The peristaltic pump of claim 3, further comprising a receptacle containing the material to be transported, wherein the receptacle is located in the main body.

6. The peristaltic pump of claim 5, further comprising at least one needle that is configured to be inserted into the receptacle.

7. The peristaltic pump of claim 5, configured such that a contraction of at least one of the piezoelements causes an inlet pressure in the tube such that the material is drawn into the tube from the receptacle.

8. The peristaltic pump of claim 1, further comprising at least one needle.

9. The peristaltic pump of claim 1, wherein the peristaltic pump is configured to transport medical fluids.

10. The peristaltic pump of claim 1, wherein the tube is arranged in a linear form.

11. A method of transporting material with the peristaltic pump of claim 1, comprising the step of successively actuating the plurality of piezoelements along the transport direction of the material and thereby causing a squeezing of the tube by the plurality of levers along the transport direction.

12. The method of claim 11, wherein at any time during an operation of the pump at least one piezoelement of the plurality of piezoelements is actuated.

13. The peristaltic pump of claim 1, wherein at least one lever of the plurality of levers is rotationally coupled with the holder at the expansion end of the holder.

14. The peristaltic pump of claim 1, wherein each of the plurality of piezoelements is held by the holder.

15. The peristaltic pump of claim 1, wherein the holder is one of a plurality of holders, and wherein each of the plurality of piezoelements is held by a different holder selected from the plurality of holders.

16. The peristaltic pump of claim 1, wherein, for each lever, a longitudinal axis of the lever is oriented perpendicular to the expansion direction of the corresponding at least one of the piezoelements during at least some of the operation of the peristaltic pump.

17. The peristaltic pump of claim 1, wherein, for each of the plurality of piezoelements, the expansion direction of the piezoelement is substantially perpendicular to a longitudinal axis of the tube.

18. The peristaltic pump of claim 1, wherein, for each lever in the plurality of levers, the rotation axis of the lever is substantially parallel to a longitudinal axis of the tube.

19. A peristaltic pump, comprising: a tube to transport a material in a transport direction; a plurality of piezoelements arranged in a row along the tube, the plurality of piezoelements being configured to expand when they are actuated to cause a squeezing of the tube; a holder having an expansion end and a blocking end, at least one of the plurality of piezoelements being held by the holder, the holder being configured to permit each held piezoelement to expand along an expansion direction toward the expansion end of the holder and configured to block movement of the piezoelement at the blocking end of the holder when the piezoelement is expanding; and a plurality of levers, each lever being arranged between a corresponding at least one of the piezoelements and the tube with the corresponding at least one of the piezoelements acting on the lever via a contact position on the lever located proximal to a rotation axis such that expansion of the at least one of the piezoelements causes a tangential displacement of the contact position and consequently a rotation of the lever about the rotation axis, and each lever being configured to convert movement of at least one of the piezoelements into amplified movement against the tube with a distance between the rotation axis and a location on the lever where the lever moves against the tube being greater than a distance between the rotation axis and the contact position.

20. The peristaltic pump of claim 19, further comprising at least one lever spring that is configured to pretension at least one of the levers in a direction that is opposed to a direction of movement of the lever caused by the expansion of at least one of the piezoelements.

21. The peristaltic pump of claim 19, further comprising a main body and an exchange part configured to be attachable to the main body.

22. The peristaltic pump of claim 19, wherein the peristaltic pump is configured to transport medical fluids.

23. The peristaltic pump of claim 19, wherein at least one lever of the plurality of levers is rotationally coupled with the holder at the expansion end of the holder.

24. The peristaltic pump of claim 19, wherein each of the plurality of piezoelements is held by the holder.

25. The peristaltic pump of claim 19, wherein the holder is one of a plurality of holders, and wherein each of the plurality of piezoelements is held by a different holder selected from the plurality of holders.

26. The peristaltic pump of claim 19, wherein, for each lever, a longitudinal axis of the lever is oriented perpendicular to an expansion direction of the corresponding at least one of the piezoelements during at least some of the operation of the peristaltic pump.

27. The peristaltic pump of claim 19, wherein, for each of the plurality of piezoelements, an expansion direction of the piezoelement is substantially perpendicular to a longitudinal axis of the tube.

28. The peristaltic pump of claim 19, wherein, for each lever in the plurality of levers, the rotation axis of the lever is substantially parallel to a longitudinal axis of the tube.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features, refinements and expediencies become apparent from the following description of the exemplary embodiments in connection with the figures.

(2) FIG. 1 shows a side view of an exemplary embodiment of a peristaltic pump with an exchange body being attached to a main body.

(3) FIG. 2 shows a side view of the peristaltic pump of FIG. 1 with the exchange body being detached from the main body.

(4) FIG. 3 shows a sectional view of parts of the peristaltic pump of FIG. 1.

(5) FIG. 4 shows an exploded view of parts of the peristaltic pump of FIG. 1.

(6) FIG. 5 shows a side view of a piezoelement and a lever mechanism of the peristaltic pump of FIG. 1.

(7) FIG. 6 shows the piezoelements and the lever mechanism of the pump of FIG. 1 from a perspective view.

(8) FIG. 7 shows different steps of the successive squeezing of the tube of FIG. 1 by the piezoelements.

(9) Like elements, elements of the same kind and identically acting elements are provided with the same reference numerals in the figures.

DETAILED DESCRIPTION

(10) FIG. 1 shows a peristaltic pump 1, wherein a plurality of piezoelements 3 is arranged in a row along a tube 2. For clarity reasons, parts of a housing 18 of the pump 1 are cut away in this Figure. The peristaltic pump 1 may be configured to transport a material. The peristaltic pump 1 is particularly suitable for microfluidic applications. Particularly, the peristaltic pump 1 may be configured to dispense small amounts of fluids. The material to be transported is moved in the tube 2 along a transport direction 4. The material may be for example insulin. Preferably, the material may be a medical fluid. The movement of the material is caused by a successive expansion of the plurality of piezoelements 3. The piezoelements 3 are electrically connected to a power supply 22 by electric cables 23.

(11) The tube 2 may be of an elastic material. Preferably, the tube 2 is arranged in a linear form such that it extends along an axis 20. The tube 2 runs linearly in a tube guide 10, which is integrated in an exchange part 9.

(12) The exchange part 9 is configured such that it may be easily attached and detached to a main body 8 of the pump 1. In this illustration, the exchange part 9 is attached to the main body 8. The exchange part 9 provides an easy and fast way to substitute the elements of the peristaltic pump 1 which should be sterile before a use of the peristaltic pump 1, in particular a needle 11 and the tube 2. In particular, the exchange part 9 carries two needles 11, 12 (see FIG. 2), whereof one needle 12 (see FIG. 2) is configured to be inserted into a receptacle 13 and the other needle 11 is configured to dispense a material from the peristaltic pump 1.

(13) The main body 8 comprises a housing 18 and the plurality of piezoelements 3. Furthermore, it may comprise at least one lever 5. The lever 5 may be arranged between the tube 2 and a piezoelement 3. The piezoelement 3 may move the lever 5 when it is actuated. The lever 5 may be configured to effect a squeezing of the tube 2. In a preferred embodiment, the pump 1 comprises a plurality of levers 5.

(14) Furthermore, the receptacle 13 is located in the main body 8. It contains the material to be transported. In a preferred embodiment, the receptacle 13 may comprise a piston. The piston may be axially movable in the receptacle 13. A spring may exert a force on the piston to facilitate a movement of the piston. Thereby, no air pockets may occur in the receptacle 13 when material is drawn from the receptacle 13 into the tube 2.

(15) In the condition shown in FIG. 1, the peristaltic pump 1 is ready to transport a material.

(16) FIG. 2 shows the peristaltic pump 1 of FIG. 1, with the exchange part 9 being detached from the main body 8. The exchange part 9 carries the tube 2 and the needles 11, 12.

(17) The exchange part 9 may be removed from the main part 8 in a moving direction 21. The moving direction 21 of the exchange part 9 may be perpendicular to the axis 20 of the tube 2.

(18) In an exemplary embodiment, it may be possible to lock the exchange part 9 to the main body 8 by a flap. The flap may have to be opened in order to detach the exchange part 9 from the main body 8. The flap may close the main body 8 in order to inhibit that dust or other contaminants may invade into the pump 1.

(19) FIG. 3 shows a sectional rear view of parts of the peristaltic pump 1 of FIG. 1. The section is cut along the line A-A as shown in FIG. 1. It shows how the lever 5 is arranged between the piezoelement 3 and the tube 2. In an exemplary embodiment of the pump 1, one piezoelement 3 may be composed of several smaller piezoelements (31, 32, 33).

(20) FIG. 4 shows an exploded view of parts of the peristaltic pump 1 of FIG. 1. The plurality of piezoelements 3 is arranged in a holder 14. The tube is arranged in a tube guide 10, which is integrated in the exchange part 9. The tube guide 10 comprises a longitudinal groove, in which the tube 2 may run. The levers 5 are arranged in a row along the tube 2.

(21) The expansion of a piezoelement 3 causes a movement 6 of at least one lever 5 around a rotation axis 15.

(22) Preferably, one end of a piezoelement 3 is in contact with the holder 14 in a way such that the piezoelement 3 may expand only in a direction towards the tube 2, and the movement of the piezoelement 3 in the opposite direction is blocked by the holder 14. When actuated, the piezoelement 3 may expand in a direction such that the distance between the tube 2 and the moving end of the piezoelement 3 decreases.

(23) Preferably, several piezoelements 3 are actuated at the same time. They may be expanded to a different size. For example, one piezoelement 3 may be expanded to its full size, while another piezoelement has just started to expand or started to contract.

(24) FIG. 5 shows a side view of a piezoelement 3, a lever 5 and the tube 2. Here, the lever mechanism and the arrangement of the lever 5 between the piezoelement 3 and the tube 2 are shown in detail. The lever 5 may oscillate between two positions 19a and 19b. The position 19a occurs when the piezoelement 3 is contracted, and the lever 5 does not squeeze the tube 2. The lever 5 is in the position 19b when the piezoelement 3 is fully expanded. In position 19b the lever 5 closes the tube 2 by squeezing the tube 2.

(25) The piezoelement 3 contacts the lever 5 in a contact area 16 of the lever 5. The contact area 16 may be configured as a protrusion on the lever 5. The lever 5 is in contact with the tube 2 in a patch 17 of the tube 2. When the piezoelement 3 expands, the lever 5 rotates in a rotational direction 6 around the rotation axis 15. The rotation axis 15 runs parallel to the axis 11 of the tube 2. The lever 5 is arranged in a way such that the piezoelement 3 meets the lever 5 in the contact area 16 of the lever 5 during its expansion. The lever 5 meets the tube 2 in the patch 17 of the tube 2 during its movement 6.

(26) When the lever 5 is moved by the expansion of a piezoelement 3, it squeezes the tube 2 and thereby displaces the material in the tube 2.

(27) When the piezoelement 3 contracts, the lever 5, which has been actuated by the piezoelement, starts to move in a direction opposite to the direction of movement 6 of the lever 5 when the piezoelement expands. Thereby the squeezing of the tube 2 by the lever 5 decreases, until the lever 5 no longer squeezes the tube 2. Thus the tube 2 can widen to its original, unsqueezed diameter.

(28) The movement of the lever 5 in a direction opposite to the direction of movement 6 of the lever 5 when moved by the piezoelement 3 may be caused by an elasticity of the tube 2. When no force is applied on the tube 2 by the lever 5, the tube 2 may strive to widen and thereby move the lever 5. However, this may not be sufficient to move the lever 5 back to the position 19a. Thus, the movement of the lever 5 in a direction opposite to its direction of movement 6 when the piezoelement expands may be supported by a lever spring 7. The lever spring 7, which may be a flat spring, makes sure that the lever 5 is drawn back from the tube 2 after the contraction of a piezoelement 3. In a further embodiment, the lever spring 7 may be a different kind of spring, for example a spiral spring. The lever spring 7 pretensions the lever 5 in a direction that is opposed to the direction of movement 6 of the lever 5 which is caused by the expansion of the piezoelement 3.

(29) FIG. 6 shows the piezoelements and the lever mechanism of the pump of FIG. 1 from a perspective view.

(30) The pump comprises five piezoelements 3a to 3e.

(31) However, the peristaltic pump 1 may also work with less than five piezoelements 3, for example with three piezoelements 3, or more than five piezoelements 3.

(32) A first piezoelement 3a is first in the sequence of the piezoelements 3 in reference to the transport direction 4 of the material. In particular, the first piezoelement is located next to the receptacle 13. In particular, the first piezoelement 3a may be closest to the receptacle 13, compared to all other piezoelements 3. Analogically, the pump 1 comprises five levers 5a to 5e. The piezoelements 3 and the levers 5 are arranged such that each of the piezoelements 3a to 3e is configured to cause a movement of one of the levers 5a to 5e. The levers 5a to 5e may squeeze the tube 2 in patches 17a to 17e.

(33) Preferably, the piezoelements 3 are successively actuated, such that the first piezoelement 3a is actuated firstly, the second piezoelement 3b is actuated secondly, the third piezoelement 3c is actuated thirdly and so forth. At a particular time, one of the piezoelements 3, for example the second piezoelement 3b, may be expanded by applying a voltage. At the same time, the third piezoelement 3c may already have started to expand, while the first piezoelement 3a may already have started to contract. Preferably, the piezoelements 3 may be driven by undulations, so that a regular material flow is generated.

(34) FIGS. 7A to 7H illustrate successive steps of a successive squeezing of the tube 2 in the case of five piezoelements 3a to 3e acting on five levers 5a to 5e as shown in FIG. 6.

(35) In FIG. 7A, none of the piezoelements 3a to 3d is actuated, such that the tube 2 is not squeezed. The pump 1 is in a non operating state.

(36) In FIG. 7B, the first piezoelement 3a is actuated and expands such that the first lever 5a is rotated and squeezes the tube 2 in a first patch 17a. Thereby, material is displaced from the squeezed patch 17a of the tube and transported forward in transport direction 4.

(37) In FIG. 7C, the first piezoelement 3a and the second piezoelement 3b are expanded such that the first lever 5a and the second lever 5b squeeze the tube 2 in the first patch 17a and a second patch 17b. Thereby, material is displaced from the squeezed patches 17a, 17b and moved forward in transport direction 4.

(38) In FIG. 7D, the second piezoelement 3b and the third piezoelement 3c are expanded such that the second lever 5b and the third lever 5c squeeze the tube 2 in the second patch 17 a and a third patch 17c. When the third piezoelement 3c is actuated and expands the first piezoelement 3a contracts.

(39) When the first piezoelement 3a contracts and the first lever 5a is withdrawn from the tube 2, a widening of the tube 2 is enabled at the first patch 17a of the tube 2. The widening of the tube 2 caused by the contraction of the first piezoelement 3a may cause an inlet pressure, such that new material flows into the tube 2 from the receptacle 13.

(40) As shown in the FIGS. 7E, 7F, 7G and 7H, the further piezoelements 3 are actuated in the same manner, such that a continuous transport of material is achieved.

(41) When all piezelements 5a to 5e have been successively actuated and the last piezoelement 3e is expanded, the first piezoelement 3a is actuated again as can be seen from FIG. 7H. After that the last piezoelement 3e contracts and the successive actuation continues with the steps shown in FIGS. 7C to 7H.

(42) Preferably, the peristaltic pump 1 is operated such that at any time during the operation at least one lever 5 squeezes the tube 2 and closes it by that, so that the material always follows the transport direction 4 and no material can flow backwards. The succession of movement 6 of the levers 5 corresponds to the successive actuation of the piezoelements 3.