WO1989007200A1

WO1989007200A1 - Tubular pump

Info

Publication number: WO1989007200A1
Application number: PCT/CH1989/000017
Authority: WO
Inventors: Rudolf A. Hatschek; Frédéric Neftel
Original assignee: Debiopharm Sa
Priority date: 1988-02-05
Filing date: 1989-01-27
Publication date: 1989-08-10
Also published as: AU2941989A

Abstract

A tubular pump comprises a housing (1) which forms a supporting surface (5b) for a tube (11). A piezoelectric ultrasonic motor comprises a drive element (21), lodged in said housing, with a piezoelectric transducer (25), a driving surface (27a) which can be deformed by the latter to form undulations, and a rotor (31). The rotor has a contact surface (37a) with which the crests of the undulations formed during operation by the driving surface (27a) engage, thereby setting the rotor (31) in rotation. The rotor (31) also comprises a pressing element (35) provided with a rolling surface (35b) on which rolling bodies (41) such as balls can roll during operation. Said rolling bodies are retained by a cage in positions disposed around the axis of rotation (33) and are urged by the pressing element (35) against the tube (11). The pump and its driving motor therefore contain few rotating parts, so that the pump can be very compact and consumes little energy during operation.

Description

Peristaltic pump

DESCRIPTION

The invention relates to a peristaltic pump according to the preamble of claim 1.

The peristaltic pump is intended in particular for the continuous or intermittent pumping and metering of relatively small amounts of an at least partially liquid fluid, i.e. a liquid or suspension. For example, for certain medical treatments, it is advantageous for a medicament in the form of a liquid or suspension to be continuous or quasi-continuous in tissue parts or possibly directly into the bloodstream of a human or animal for a longer period of time, for example for a few days or weeks Pump body into it, with the desired delivery rate for example

3 can be between 0.1 and 1 mm / min. With the quasi-continuous, intermittent supply, it can be advantageous, for example, to carry out an approximately 10 to 30 second burst of liquid every minute.

Peristaltic pumps are now known on the market, for example, which have a housing with an arcuate support surface, a hose resting thereon and a pressing member rotatably mounted in the housing. On this, rollers are mounted with bearings, which roll during operation along the section of the hose resting on the support surface and compress it in the process. There is a drive device for rotating the pressing member, which usually has an electric motor that uses electromagnetic induction and a reduction gear. A peristaltic pump with such a drive device thus has a relatively large number of separately rotatably mounted parts, namely the pressing member, the rollers mounted on it, the rotor of the electric motor and the gear wheels of the reduction gear. Furthermore, the peristaltic pump provided with such a drive device requires, in addition to the housing forming the support surface for the hose and the pressing member, also separate housings for the electric motor and the reduction gear or at least supports and the like for holding the ones for mounting the rotor of the motor and the gears of the reduction gear required bearings. The large number of rotatably mounted parts and the toothed gears of the reduction gear which mesh with one another cause a relatively large amount of friction, so that high losses occur when electrical energy is converted into mechanical energy that can be used for pumping. A peristaltic pump with an induction electric motor therefore requires a relatively large amount of space in order to achieve delivery rates of only about 1 mm / min or less, is accordingly heavy and consumes a lot of electrical energy during operation. If such a pump is to pump fluid intermittently for a longer period of time, for example for a few days, or with short interruptions, then either a connection to the AC voltage network or a large battery must be provided to power its motor. If a medication pump of this type is to be used to pump medication into the body of a patient for a few days or weeks, the patient is forced to guard the bed practically during the entire duration of the supply of the medication. In addition, the manufacture of such pumps is relatively complex, which is a major disadvantage in particular if they are intended for single use. The object of the invention is therefore to create a hose pump which eliminates disadvantages of the known pumps and is particularly suitable for very small, for example in size

3 of 1 mm / min or lower pump rates suitable and in

Compared to the pumping rate, it should be small, light and inexpensive to manufacture and should require as little electrical energy as possible during operation.

This object is achieved by a pump which, according to the invention, has the features of claim 1. Advantageous embodiments of the pump emerge from the dependent claims.

The subject of the invention will now be explained with reference to exemplary embodiments shown in the drawing. In the drawing shows

1 shows a schematic section through a peristaltic pump with a piezoelectric motor, the rotor of which has on one end face a rolling surface for rolling balls on the tube,

2 shows a section of FIG. 1 on a larger scale,

FIG. 3 shows a top view of a sector of the ball-holding cage,

FIG. 4 shows a developed section along the path of the balls through that section of the housing in which the hose is led away from the bearing surface of the housing,

FIG. 5 shows a schematic section through an area of a pump which has conical roller bodies instead of balls. 6 shows a schematic plan view of that sector of the support surface formed by the housing of the pump according to FIG. 5, in which the hose is guided away from the support surface,

7 shows a section through a region of a pump in which the rotor presses the balls against the hose in a direction inclined away from the axis of rotation,

FIG. 8 shows a section through a region of a pump in which the rotor presses the balls against the hose in a direction inclined towards the axis of rotation,

FIG. 9 shows a section through a region of a pump in which the balls rolling on the hose are pressed against the hose by a pressing member which rolls on the rotor of the motor via another ring of balls.

FIG. 10 shows a schematic section through a pump, the balls of which are pressed onto the hose in the radial direction,

FIG. 11 shows a plan view of the outer surface of mutually overlapping end sections of ring parts of the rotor of the pump shown in FIG. 10,

FIG. 12 shows an oblique view of a reservoir for a fluid to be pumped and formed by a flexible bag

FIG. 13 shows a highly schematic sectional illustration of a pump with two hoses.

The peristaltic pump shown in FIG. 1 has a housing which is closed on all sides and has at least a generally cylindrical urinary crack. The housing 1 has its one Front wall forming, plate-shaped housing part 3 and a housing part 5 firmly connected to this, which forms the casing and the other end wall of the housing. The interior enclosed by the casing of the housing part 5 has an extension in which the housing part 5 forms a radial surface 5a facing the housing part 3. This is provided with a trough running along it, concave in cross section and namely having the shape of a flat arch, which can be seen particularly clearly in FIG. 2 and which is intended as a support surface 5b. The housing part 5 is provided in its interior between the housing part 3 and the radial surface 5a and close to the latter with an inwardly projecting, annular rib, the cylindrical or possibly slightly concavely curved inner surface of which serves as a guide surface 5c.

A hose 11 made of elastic and preferably rubber-elastic material has a section lying on the bearing surface 5b, forming an approximately full circle and namely extending over a central angle which is at least approximately 330 ° and for example at least or approximately 350 °. A hose end section 11a or 11b connects to the two ends thereof.

An electrical motor, namely a so-called piezoelectric ultrasonic motor, is also arranged in the housing 1. As the stator, the latter has an annular drive element, designated as a whole as 21, which is attached to the housing part 3 via an annular support 23, which is made of felt and serves to isolate and dampen vibrations. The drive member 21 serves in a manner described in more detail as a vibrator and has a piezoelectric transducer 25 for converting electrical signals supplied to it into forces and / or deformations and / or movements. The transducer 25 has at least one piezoelectric element, which is formed, for example, from an annular disk, from piezoelectric, ceramic material and is provided with electrodes. A possible design of a transducer for generating vibrations and / or waves of the desired type described in more detail is known, for example, from EP-A-0 169 297, to which reference is hereby expressly made. The transducer disclosed in this publication has two circular, piezoelectric disks and electrodes arranged one above the other. On the side of the transducer 25 facing away from the housing part 3, the transducer 25 is firmly connected to an annular, well elastically deformable and oscillatable oscillating body 27. On its side facing away from the transducer, the latter has a radial drive surface 27a which is flat in the idle state and is said to have good oscillation and waveguiding properties for elastic waves with frequencies in the sound and, in particular, ultrasound range, and also to be abrasion-resistant. The vibrating body 27 is preferably made of a metallic material, such as aluminum or stainless steel.

The ring-shaped rotor 31 of the motor, which can be rotated about an axis of rotation 33, has a pressure element 35 consisting of a dimensionally stable, for example metallic ring, which is provided on its end face facing the drive element 21 with a contact layer 37 which is level with the drive surface 27a , Forms radial and right-angled contact surface 37a to the axis of rotation 33. The contact layer 37 consists for example of polyamide fibers connected with polyimide. On its end face facing the bearing surface 5b, the pressing member 35 has a radial surface 35a which is perpendicular to the axis of rotation 33 and which in its central cross-sectional area has a channel which is concave in cross section and arcuate and serves as a rolling surface 35b. Furthermore, there is a ring of rolling bodies 41, namely balls, which can roll on the rolling surface 35b, preferably at least four, namely eight rolling bodies. As can be seen from FIG. 3, the rolling elements 41 are held by a cage 43 which can be freely rotated about the axis of rotation 33 such that there is a free space between adjacent rolling elements, the rolling elements enclosing the circular path surrounding the axis of rotation 33 The measured distance between adjacent rolling elements is greater than the diameter of the rolling elements and is, for example, at least three times or approximately or at least five times the diameter of the rolling elements. The circular center line of the rolling surface 35b has the same diameter as that of the bearing surface 5b. The axial distance of the rotor 31 from the bearing surface 5b is dimensioned such that the rolling bodies compress the hose 11 when they roll on the rolling surface. If one understands the pressure path as the distance by which the hose is pressed together by a rolling body, starting from its circular cross-sectional shape taken in the relaxed, undeformed state, this pressure path should be at least equal to the inner diameter of the molded hose and preferably greater than this his. The pressure path can, for example, be at least 10% and approximately up to 20% larger than the inner tube diameter. This ensures that the passage of the hose at the point of attack of a rolling element is completely closed, as can be seen from FIG. 2. At the point of attack of a rolling element, the area of the tube that is in contact with it is at least partially concavely curved. The hose resting on the cross-section, which is also concave, therefore not only supports the rolling elements in the axial direction, but also guides them radially. Furthermore, the rolling elements are additionally guided radially through the guide surface 5c. FIG. 4 shows that point on the path of the rolling body at which the hose end sections 11a and 11b are first arched through a hole in the housing part 5 and then guided away from the bearing surface 5b in the axial direction. At the lead-out point, an intermediate piece 45 is fastened in the housing part 5 between the hose sections bent away from the support surface, on the surface 45a of which the rolling elements can roll between the two ends of the hose section resting on the support surface 5b.

In the housing 1 there is also a reservoir 51, which is sealed in a gas-tight manner from the environment everywhere, for receiving the fluid to be pumped, namely a medicament consisting of a liquid or suspension. The wall of the reservoir is at least partially flexible and namely has a bellows 51a, so that the volume of the reservoir 51 adapts to the decreasing amount of fluid when fluid is pumped out under the influence of the ambient air pressure. The reservoir is provided with a filling connection 59, into which an injection needle or the like can be inserted to fill the reservoir and which closes tightly after the needle has been pulled out. The hose end portion 11a is connected to an outlet 55 of the reservoir. The other hose end section 11b is connected to a cannula 57, which can be inserted into the body tissue of a human or possibly animal for use of the pump.

In the interior of the ring-shaped motor formed by the drive element 21 and rotor 31 there is an electronic device 71 electrically connected to the electrodes of the converter 25 with at least one manually adjustable actuator 73 and a battery 75 serving to supply power to the converter 25 and the electronic device 71 arranged, wherein there may also be a switch for switching the pump on and off. When the pump is operating, the electronic device 71 supplies the piezoelectric transducer 25 with electrical signals, for example in accordance with EP-A-0 169 297 already cited, so that the transducer excites at least one oscillation and / or wave with a frequency in the ultrasound range . At least one elastic wave then propagates around the axis of rotation 33 in the oscillating body 27. The wave normally consists of a longitudinal wave and a slower propagating transverse wave. These two superimposed shafts or partial shafts generate a surface wave that bends in a wave-like manner on the drive surface. The drive member 21 thus acts as an ultrasonic vibrator during operation. The apexes of the wave crests formed on the drive surface move along closed tracks and, when they come into contact with the contact surface 37, transmit a force to it and thus to the rotor, which rotates the rotor. For further details, reference is again made to EP-A-0 169 297.

When the rotor 31 is rotated by the drive member 21 during operation, it or, more precisely, its pressing member 35 rolls the roller body 41 on the section of the tube 11b lying on the bearing surface 5b and presses the roller body against the tube. As a result, the tube is progressively compressed in sections, so that fluid present in the tube is conveyed by displacement according to the peri-static principle and is pumped from the reservoir 51 to the cannula 57 when the rotor rotates in a corresponding direction.

The ultrasonic motor can generate a relatively large torque at low speeds. In addition, the rotational speed and angular speed at which the rolling bodies and the cage move about the axis of rotation are only half as large as the rotational speed or angular speed of the roller body due to the rolling of the rolling bodies on the rolling surface 35b Rotors. To a certain extent, the rolling of the rolling elements results in a reduction in the speed to half, which corresponds to a doubling of the torque of the rolling elements which is effective with the hose with respect to the axis of rotation 33.

Due to its elasticity and the resistance of the pumped fluid, the hose 11 exerts a counterforce on the rolling elements. This can be broken down into a tangential force tangential to the circular path of the rolling elements, to be overcome by the already mentioned torque of the rolling elements, and into a compressive force perpendicular thereto and namely parallel to the axis of rotation 33. The latter is transmitted to the rotor 31 via the roller body and presses it resiliently against the drive element 21 serving as a vibrator. This ensures that the rolling movements of the wave crests formed on the drive surface by vibrations ensure good power transmission to the Contact surface 37a of the rotor.

From the preceding description it can be seen that various parts of the pump perform a multiple function: the housing 1 serves simultaneously as the bearing surface 5b for the pump housing forming the hose and as a motor housing. The hose 11 is used for the peristaltic conveying of fluid and as an elastic, resilient element for resiliently pressing the rotor against the drive element 21, which operates during operation as a vibrator. The roller bodies 41 are used to support the rotor 31 and to rotate and rigidly connect it and this at least essentially - ie apart from the possibly omitted contact layer 37 - forming pressure element 35, for reducing the speed, for compressing the hose and for transmitting the counter-pressure force generated by it to the rotor.

The pump and the motor used to drive it therefore have only very few rotatable parts, namely the pressure organ having rotor 31 and the rolling elements with the cage holding them. The pump can therefore be made very small and light in relation to a delivery rate provided. Since the piezoelectric ultrasound motor produces a high degree of efficiency even at low speeds and since the small number of rotatable parts results in very low friction losses, the pump requires only little electrical energy for its operation and can therefore be used for a long time from a small battery be powered.

The tube section resting on the bearing surface 5b is compressed in each position of the cage by at least seven and in most cage positions by eight roller bodies in such a way that its passage is completely closed. The passage of the hose is therefore blocked properly and reliably when the rotor is at a standstill. In addition, a piezoelectric motor is well suited for intermittent operation. It is therefore easy to operate the pump intermittently and periodically pump the at least partially liquid medication intermittently from the reservoir into a patient's body tissue, for example, as already mentioned in the introduction, every minute for about 10 to 30 seconds, namely about 15 fluid can be pumped intermittently up to 20 seconds. Such an intermittent supply of a medicament can in many cases increase its therapeutic effect. In addition, the good shut-off of the hose when the rotor is at a standstill ensures that in the event of a malfunction of the engine, neither liquid medication from the reservoir enters the body tissue in an uncontrolled manner nor, conversely, body fluids enter the reservoir.

The at least one actuator 73 makes it possible to set the speed of the motor or, if pumping is to be carried out intermittently, instead or additionally, the time intervals and or lengths of the pumping intervals. The pumping rate or in the case of intermittent operation, the mean value of which can be set and metered precisely. For example, a reservoir with a volume of 2 cm and a pumping rate of approximately 0.28 mm / min can be provided, which makes it possible to deliver a medicament to a patient continuously for 5 days or quasi continuously and intermittently in the manner mentioned.

Since the pump can be made very small and, for example, has an outside diameter of a few centimeters, it can be attached to the body of the person to be treated. The design of the pump and the reservoir make it possible for the pump to be able to pump fluid in any position with respect to the environment and regardless of the direction in which gravity acts on it. A patient equipped with a pump can therefore move around largely unhindered and continue his normal work.

The parts of the pump that come into contact with the fluid to be pumped, i. H. the tube 11 and the reservoir 51 can be made sterile by heating and / or with chemical substances, and the piezoelectric motor and possibly even the electronic device can be designed in such a way that they can withstand the temperatures occurring during the sterilization by heating without damage.

The pump shown in part in FIGS. 5 and 6 has a housing 101 with a housing part 105, a hose 111 with end sections purple, 111b, a drive member 121 with an oscillating body 127 forming a drive surface 127a and a rotor 131 with a pressure member 135 and one a contact layer 137 forming a contact surface 137a. These parts are at least largely similar to the corresponding parts of the pump shown in FIGS. The pump according to FIGS. 5 and 6 differs however, of the pump according to FIGS. 1 to 4 in that its bearing surface 105b is flat and outward in cross-section, ie it is inclined slightly upwards away from the axis of rotation of the rotor, not shown. Furthermore, the rolling surface 135b lies in a radial plane. Instead of the rib of the housing part 5 forming the guide surface 5c, a separate guide ring 107 forming the guide surface 107c is provided on the housing part 105. Instead of balls, the rolling bodies 141 consist of conical rollers that become thicker on the outside, accordingly have a conical outer surface with which they can roll on the rolling surface 135b and the hose 111, and are in the cage 143 by a slight inclination against a radial plane ¬ axes 147 rotatably mounted. The center line of the main part of the tube section resting on the bearing surface 105b runs along the circular line denoted by 149 in FIG. 6. In the vicinity of the point at which the hose ends purple, 111b are led away from the support surface, the hose section resting on this is offset on circular sides 149 on sides facing away from one another. The two ends of the hose section resting on the support surface can therefore overlap a little according to FIG. 6. If the length of the roller-shaped roller body 141 is made at least equal to twice the width of the compressed tube, the roller bodies roll as they pass the point at which the tube ends are led away from the support surface, but the overlapping ends of the tube section lying on top. The rolling elements can therefore rest on the tube without interruption along their entire path.

The pump, which is partly shown in FIG. 7, has a housing 201 with housing parts 203 and 205 and a hose 211. The housing part 205 forms a support surface 205b with a cross-section, the perpendicular bisector of which in cross section from the support surface to the axis of rotation of the rotor 231 is inclined. The drive member 221 is in turn ring shaped, but the side surfaces of the ring are formed by mutually parallel conical surfaces which are inclined outwards from the housing part 203. The piezoelectric transducer 225 of the drive member is attached to the housing part 203 via a support 223 made of fil and a support ring 229. The rotor 231 is also ring-shaped and has side surfaces which are inclined in the same way as the drive element. The rotor in turn has a pressure element 235 and a contact layer 237 with a contact surface 237a. This and the drive surface 227a, which is in the idle state, are likewise conical and namely inclined away from the axis of rotation of the rotor towards the housing part 203. The pressure element 235 has on its side facing away from the drive element a conical surface 235 which is inclined in the same way as the contact surface. In its central region, this has a groove which is curved in cross section and serves as a rolling surface 235b. The rolling elements 241 consist of balls and are held in a cage 243. The rolling elements can therefore transmit a pressure force inclined to its axis of rotation between the hose and the rotor and thereby also press the rotor against the drive member.

The pump, which is partly shown in FIG. 8, in turn has a housing 301 with two housing parts 303 and 305. The housing part 305 forms a cross-sectionally concave and arc-shaped support surface 305b, the vertical perpendicular of which protrudes from it is inclined in cross-section away from the rotor axis of rotation . A section of a hose 311 lies on the support surface 305b. The drive member 321 is of similar design and is fastened to the housing part like the drive member 21. The rotor 331 is provided on its side facing the drive member with a contact layer designed in the same way as the contact layer 37 and has on its side facing away from the drive member a conical surface 335a facing the support surface 305b . This has a groove which is concavely curved in cross section and forms a rolling surface 335b. On this roller body 341, namely balls, roll, which are held by a cage 343 and the hose against the Press the contact surface. In this pump, the pressure force resulting from the compression of the hose, which is transmitted via the roller bodies 341 to the pressure element 335 and presses the rotor 331 resiliently against the drive element 321, is not directed at right angles to the contact surface and to the drive surface which is in the idle state. but at least the largest component of this pressure force is axially directed and is at right angles on the said surfaces.

FIG. 9 shows part of a pump, the housing 401 of which has a housing part 405 which is configured similarly to the housing part 5. The housing part 405 has in particular a radial surface 405a which is provided with a groove which is concavely curved in cross section and serves as a support surface 405b. A hose 411 lies on the support surface. The housing part 405b also has a guide surface 405c corresponding to the guide surface 5c and on the side facing away from the radial surface 405a a guide surface 405d formed in an analogous manner by an annular rib. The drive element, not shown, can be designed the same or similar to the drive element 21. A rotor 431 which can be rotated about an axis of rotation 433 is essentially the same as the rotor 31 and has a ring 435 which is formed in accordance with the pressing member 35 and has a rolling surface 435b which is concavely curved in cross section. A pressing member 439 formed by another ring has a first rolling surface 439b on its front side facing the bearing surface 405b and a second rolling surface 439c on its front side facing the rotor. Between the first rolling surface 439b and the hose 411, rolling elements 441, which are held by a cage 443, are arranged from balls. Rolling bodies 447 are arranged between the rolling surface 435b of the rotor ring 435 and the second rolling surface 439c of the pressing member 439, which in turn consist of balls and are held by a cage 449. The pump according to FIG. 9 operates similarly to that with reference to FIGS. 1 to 4 described pump. However, since the pressing member 439 is not rigidly connected to the rotor, but is in rotary connection with the rotor via the rolling elements 447, there is an additional reduction in the speed by a factor of 2 and accordingly an additional increase in the rotations around the rotor axis of rotation measured torque of the roller bodies 441 compressing the hose.

The pump according to FIG. 10 has a housing 501 with two housing parts 503 and 505. The cylindrical inner surface of the latter is provided with a channel which is concave and curved in cross section and serves as a support surface 505b. The housing part 505 also has an annular rib projecting into its interior, which on its side facing the housing part 503 forms an at least generally radial and flat guide surface 505c. A hose 511 rests on the support surface 505b. An annular drive element 521 has an annular, piezoelectric transducer 525 on its inner side and an annular oscillating body 527 on its outer side, which is attached to the housing part 503 via a pad 523 made of felt, and one in the idle state on its outer side facing away from the transducer has circular cylindrical drive surface 527a. The rotor 531, which is rotatable about an axis of rotation 533, has a ring 535 which is formed from a plurality of, for example three, ring parts 536 which extend over circular sectors of the same size. As can be seen from FIG. 11, the ring parts 536 have protrusions 536a which overlap in pairs at their abutting ends. The three ring parts are designed such that they can be displaced to a limited extent in the radial direction and are held together by a rubber band 539 surrounding them and pressed radially inwards. The ring 535 formed from the three ring parts 536 and the rubber band 539 together form the pressing member. The three ring parts are provided on their inner circumferential surface with a contact layer 537 whose cylindrical surface facing the drive element forms the contact surface 537a. The outer circumferential surface of the ring parts is provided with a groove which is curved in cross section. The generally cylindrical outer surface of the rubber band is pressed into the groove of the ring parts, at least in the case of the rolling elements 511 consisting of balls, and forms the rolling surface 539b. The rolling elements are held in positions evenly distributed around the axis of rotation 533 by a cage 543. During operation, the rolling elements can roll on the rolling surface 539 of the rotating pressing element 535, 539 and are pressed against the hose 511 by the pressing element 535, 539, the rolling elements being guided through the guide surface 505c and the cage sliding along the housing part 503 and against axial displacements are secured. An electronic device 571 and a battery 575 are fastened to the housing part 503 in the space enclosed by the piezoelectric transducer. The piezoelectric transducer 525 excites at least one oscillation or wave during operation, so that an elastic wave, which extends around the axis of rotation 533 and which generates a surface wave on the drive surface 527a, is created in the oscillating body 527. This forms in the radial direction over the wave troughs projecting outward wave crests, which transmit forces to the contact surface 537a and thereby rotate the rotor. For further details of a piezoelectric ultrasonic motor working using such surface waves, reference is made to FR-A-2 522 216. Otherwise, the pump shown in FIG. 10 operates in a similar manner to that described for the pumps shown in FIGS. 1 to 4, but the rolling elements 541 in the pump according to FIG. 10 transmit radially directed compressive forces between the hose and the rotor and the Press ring part 536 of the latter against the drive element in the radial direction.

In the pump shown in FIG. 10, the balls serving as rolling bodies could be replaced by reflectors with circular-cylindrical outer surfaces. The hose could then be led away from the support surface in a similar manner as is shown in FIG. 6.

FIG. 12 shows a variant of a reservoir, which is designated by 651 and, instead of the reservoirs having a bellows shown in some of the previously described figures, can be arranged in the pump housings. The reservoir 651 consists of a bag with a flexible wall, for example made of a rubber-elastic material, and is connected to a tube 611, which together with the reservoir forms an inseparable unit and is connected to a cannula 657 at its end facing away from the reservoir. The reservoir 651 can, for example, be inserted into the housing of a pump when filled, after which a section of the hose 611 is placed on the bearing surface of the housing.

It should be mentioned in this connection that the direction of rotation of piezoelectric motors can be changed by changing the electrical signals supplied to them. The electronic devices of the pumps could therefore also be equipped with a switch with which the direction of rotation can be changed. This makes it possible to fill a reservoir present in the pump in question by pumping in the desired fluid and then changing the direction of rotation of the pump for its normal use.

The pump, which is shown very schematically in FIG. 13, has a housing with a support surface on which sections of two hoses 711 rest, each of these hose sections extending approximately over half the circumference of the support surface. A rotor 731 presses with a pressing member on a rolling surface rollable roll body against the hoses. This design of the pump enables two different fluids to be separated simultaneously to pump each other. In this way, for example, two different drugs can be pumped into a body tissue at the same time, which is advantageous in certain cases.

Of course, different features of the previously described embodiments of the pump according to the invention can be combined with one another in different ways.

Claims

PATENT CLAIMS

1. Peristaltic pump with a housing (1) at least one hose (11) lying on a bearing surface (5b) formed by the latter, an electrically drivable motor, a rotor (31) which can be rotated about an axis (33) and by this Rolling bodies (41) movable around the axis (33), rolling at least in a region of their path on a section of the hose (11) and compressing them, characterized in that the motor has a drive element (21) with a piezoelectric transducer (25) for generating at least one vibration and / or elastic shaft and thereby having an elastically deformable drive surface (27a) in order to rotate the rotor (31) by forces transmitted from it to a contact surface (37a).

2. Peristaltic pump according to claim 1, with a rotationally operatively connected to the rotor (31) pressing member (35) for pressing the rolling elements onto the hose (11), characterized in that the pressing element (35) has an annular shape on the rolling elements (41) has adjacent rolling surface (35b), so that the rolling bodies (41) can be rolled on the rolling surface (35b) when the pressing member (35) is rotated.

3. Peristaltic pump according to claim 1, characterized in that the pressing member (35) is non-rotatably and preferably rigidly connected to and / or formed by the rotor (31).

4. Peristaltic pump according to claim 1 or 2, characterized in that the rotor (431) has a rolling surface (435b) which surrounds the axis of rotation (433) in an annular manner, and the pressing member (439) also faces the hose (411) , first-mentioned rolling surface (439b) has a second rolling surface (439b) facing the rolling surface (435b) of the rotor (431) and that between the rolling surface (435b) of the rotor (431) and the second rolling surface (439c) of the pressing member (439) rollable rolling bodies (447) are arranged on these rolling surfaces (435b, 439c).

5. Peristaltic pump according to one of claims 1 to 4, characterized in that the rolling elements (41) are balls.

6. Hose pump according to one of claims 1 to 5, characterized in that the rolling bodies (141) have circular cylindrical or conical outer surfaces.

7. Peristaltic pump according to one of claims 1 to 6, characterized in that the rolling bodies (41) also serve for the rotatable mounting of the rotor (31).

8. Peristaltic pump according to one of claims 1 to 7, characterized in that the bearing surface (5b) is arranged in such a way that a resultant by the compression of the deformable hose (11), at right angles to tangents to the rolling element web, via the rolling elements ( 41) transferred to the rotor (31) compressive force, the contact surface (37a) and

Drive surface (27a) resiliently presses against one another or has at least one component causing such a pressing against one another, the drive member (21) preferably being fastened to the housing (1) and the contact surface (37a) being formed by the rotor (31).

9. Peristaltic pump according to claim 8, characterized in that the bearing surface (5b) is arranged in such a way that said pressure force transmitted between the hose (11) and rotor (31) via the rolling element (41) is at least essentially or completely is axially directed and / or at least has a larger axial than radial component and that the drive surface (27a) forms an angle in the idle state and the contact surface (37a) with the axis of rotation (33), the drive surface (27a) and the Contact surface (37a), for example, are flat and at right angles to the axis of rotation (33).

10. Hose pump according to claim 8, characterized in that the bearing surface (50b) is arranged such that said pressure force transmitted between the hose (511) and the rotor (531) via the rolling elements (541) is directed at least substantially or completely radially and / or at least has a larger radial than axial component, for example the drive surface (527a) which is in the idle state and the contact surface (537a) to the axis of rotation (533) are coaxial cylinder surfaces.

11. Peristaltic pump according to one of claims 1 to 10, characterized in that there are two fluid-separated hoses (711), each resting on the one or one support surface, on which the rolling bodies (741) can be rolled up alternately along their circular path, so that two fluids can be pumped separately from each other at the same time.

12. Peristaltic pump according to one of claims 1 to 11, characterized in that in the housing (1) an electrically connected to the piezoelectric transducer (25) Elektronik¬ device (71) and an electrically connected to this battery (75) and one with the a reservoir (51) connected to one end of the hose (11) is arranged for receiving a fluid which is at least partially liquid, for example consisting of a liquid or suspension, and that the reservoir (51) - apart from its connection to the hose (11 ) - Completely sealed off from the environment and at least partially limited by a deformable wall, so that the volume of the reservoir interior when pumping out fluid can decrease in accordance with the decrease in the amount of fluid stored and the pump in terms of Any surrounding layers of fluid can be pumped out of the reservoir (51), the wall of the Reservoirs are preferably partly formed by a bellows (51a) or by a deformable, for example rubber-elastic bag, which is, for example, non-detachably connected to the hose (611) and possibly together with this consists of a one-piece body.