DE102021119947A1 - Gear pump with axial force compensation device - Google Patents

Abstract

Gear pump (50) for conveying a liquid medium, having: a housing (510) with an inlet (511) and an outlet (512), and a magnetized drive gear wheel (531) arranged in the housing for conveying the liquid medium from the inlet (511) to the outlet (512), the gear pump being set up in such a way that the drive gear (531) can be driven magnetically and through-free by an external drive device (90); wherein the gear pump also has an axial force compensation device (1501) which is set up to counteract a force acting in the axial direction from the external drive device (90) on the magnetized drive gear wheel (531). A corresponding drive device (90) and a corresponding system (2) are also proposed.

Description

The present disclosure relates to gear pumps, and more particularly to a low profile gear pump. The present disclosure also relates to the field of medical technology and gear pumps for medical technology applications.

Gear pumps are known from the prior art. These are conveying devices for conveying a medium or a liquid. Gear pumps usually consist of three components, a housing with inlet and outlet and usually two gears. Depending on the arrangement and type of gears, a distinction is made between external gear pumps, internal gear pumps, gerotor pumps and screw pumps. Within the scope of this disclosure, the term gear pump is used in general. In an external gear pump with involute gearing, the medium to be pumped is transported in the spaces between the teeth and the housing. The pump is robust and inexpensive due to its simple design. In the case of internal gear and gerotor pumps, the driving gear wheel runs eccentrically in the internal teeth of a toothed ring. In a gerotor pump, the medium is conveyed through the displacement space between the tooth gaps, which changes in volume. In the case of the sickle pump, the medium to be pumped is conveyed in two spaces between the tooth gaps of the two gear wheels, which usually have involute teeth, with the teeth being sealed by the sickle. Both designs also differ in the size ratios of the gear wheel and toothed ring. The outer ring of a gerotor pump usually has exactly one tooth more than the inner wheel, mostly with trochoidal gearing. With the internal gear or sickle pump, the difference is so great that the sickle has room between the gears. Another name for the gerotor pump is the Eaton pump.

In conventional prior art gear pumps, the gears are driven by a shaft that is guided to the outside through a shaft seal and is mechanically flanged to a drive unit there. Therefore, complete hermetic encapsulation is not possible. This is particularly disadvantageous for applications in the field of medical technology. Furthermore, a particularly flat design or low overall height is desirable in certain applications, for example so that the gear pump can be easily integrated into closed fluid circuits.

DE 10 2018 105 674 B3 , a previous application by the applicant, discloses a fluid-filled cooling pad, in particular for human or veterinary medical applications, with a first heat exchanger; a second heat exchanger, a heat transfer fluid; a piping system; and an integrated pump device (circulation pump) for the heat transport fluid; wherein the heat transport fluid flows through the first heat exchanger and the second heat exchanger; wherein the piping system fluidly connects the first heat exchanger to the second heat exchanger; wherein the pumping device is set up to bring about an exchange of the heat transport fluid between the first heat exchanger and the second heat exchanger; and wherein the cooling pad has a hermetically sealed fluid circuit for the heat transport fluid, wherein the fluid circuit has the first heat exchanger, the second heat exchanger, the line system and the pump device. Furthermore, a corresponding cooling device is proposed, in particular for human or veterinary medical applications, with a receptacle set up to accommodate a heat exchanger of a cooling pad described above and a cooling device, the cooling device being set up to supply heat to the heat exchanger of the cooling pad or to remove it from it when the heat exchanger of the cooling pad is in the holder. The cooling device can also have a drive device that is set up to drive a pump device that is integrated in the cooling pad.

The pump device described in DE 10 2018 105 674.5 can be designed to be driven by an external drive device without a bushing. In other words, the pump device preferably has no additional opening for the drive device. As a result, the probability of a heat transport fluid escaping can be reduced. One advantage of this configuration can be that the cooling pad with its hermetically sealed fluid circuit is even better sealed off from the outside world. The pumping device preferably has no mechanical, electrical and/or fluidic feedthrough. For example, no mechanical passage is provided for a drive axle of the pumping device. According to a development, the pump device can be magnetically coupled to an external drive device. In particular, the pumping device can be a magnetically coupled gear pump. The power can thus be transmitted magnetically without being carried through.

Against this background, it is an object of the present disclosure to provide a further improved gear pump, in particular for human or veterinary applications. In particular, it would be desirable worth enabling more efficient operation of a gear pump.

According to a first aspect of the present disclosure, a gear pump for conveying a liquid medium is provided, comprising: a housing with an inlet and an outlet, and a magnetized drive gear arranged in the housing for conveying the liquid medium from the inlet to the outlet, the gear pump being configured to do so is that the drive gear can be driven magnetically (and through-free) by an external drive device. The gear pump can also have an axial force compensation device which is set up to counteract a force acting in the axial direction on the magnetized drive gear wheel from an external drive device.

According to a second aspect of the present disclosure, a drive device for a gear pump is proposed, the gear pump having a magnetized drive gear arranged in a housing of the gear pump for conveying the liquid medium from an inlet to an outlet of the gear pump, the drive device having a magnetic spur gear coupling and is set up to drive the drive gear of the gear pump magnetically and without bushings; and an axial force compensation device configured to counteract a force acting in the axial direction from the drive device on the magnetized drive gear. The axial force compensation device is therefore not necessarily part of the gear pump, but can also be part of the drive device. This is particularly advantageous when the gear pump is designed as a disposable part, especially in medical applications. For example, the drive device can be used for different patients, whereas the pump device is part of a patient-specific disposable item.

According to a further aspect of the present disclosure, a pump system is proposed with a gear pump for delivering a liquid medium; a drive device; and an axial force compensation device; wherein the gear pump has a housing with an inlet and an outlet, and a magnetized drive gear arranged in the housing for conveying the liquid medium from the inlet to the outlet, the gear pump being set up so that the drive gear can be driven magnetically and without a passage by the (external) drive device is; wherein the axial force compensation device is set up to counteract a force acting in the axial direction from the drive device on the magnetized drive gear wheel. It can be provided as a system with the combination of gear pump, axial force compensation device and drive device.

According to a further aspect of the present disclosure, the use of an overrunning (non-driven) magnetic spur gear clutch is proposed to counteract a force acting in the axial direction from a drive device on a magnetized drive gear of a gear pump. The free-running magnetic spur gear clutch can be arranged on a side of the magnetized drive gear opposite to a magnetic spur gear clutch of the drive device.

It goes without saying that the gear pump, the drive device and the pump system can have similar or identical corresponding developments, as described in detail below for the disclosed gear pump.

The inventors have recognized that there is a need for cost-effective, precise and contamination-free pumping devices, particularly in the field of medical technology and laboratory technology. Here, it is desirable to be able to reuse the driving means for several applications, whereas the pumping means can be designed as a disposable part. In this way, contamination and hygiene problems can be avoided. So-called hose or peristaltic pumps are often used in medical applications. This is a displacement pump in which the medium to be pumped is pushed through a hose by external mechanical deformation. The tubing can be used as a patient-specific disposable part to meet the high hygiene standards in medical and laboratory applications. However, the handling of such peristaltic pumps is complicated. Errors can occur, in particular if the hose is not correctly inserted into the drive device. For example, the correct amount of liquid is not transported or there is a functional failure if an incorrectly inserted tube jams.

Gear pumps can help here. However, conventional gear pumps were too complex and expensive for use in medical disposables. In the one mentioned above DE 10 2018 105 674 B3 a gear pump is already disclosed, which can be part of a cooling pad and is suitable for use in disposable medical items. Such a gear pump can be driven magnetically and is therefore can be operated without bushings and completely encapsulated. The inventors have recognized that a flat design is advantageous in many applications. For example, a pump device with a flat design can easily be integrated into medical devices such as a cooling pad. In order to enable a simple and cost-effective construction, the gear pump can be set up in such a way that the drive gear can be driven magnetically by an external drive device. In other words, the drive gear can be driven directly or immediately magnetically, ie it is not necessary to provide a drive shaft via which the drive gear is driven. For example, it is not necessary to provide separate magnets at a distance from the gear on a shaft protruding from a gear, which could then be driven. Instead, the drive gear of the gear pump itself can be driven magnetically by an external drive device.

The inventors have recognized that such a drive can lead to frictional losses, higher wear and/or higher power consumption, since the magnetically driven drive gear wheel is always subjected to an axial magnetic force by the external drive device and could be pressed against a wall of the gear pump. An improved mounting of the drive gear within the gear pump could in principle provide a remedy here, but such a mounting would be complex and associated with disproportionately high costs, especially in the case of disposable products. In addition, lubricants provided in a bearing could lead to contamination of the medium to be conveyed. The inventors therefore propose providing an axial force compensation device that is set up to counteract a force acting in the axial direction on the magnetized drive gear wheel from an external drive device. In the context of the present disclosure, the axial direction means a direction along the axis of rotation of the drive gear.

The gear pump can be set up to be driven by the external drive device by means of a magnetic spur gear coupling. Thanks to the magnetic drive, no mechanical axis is required, which would extend from an external drive device to the drive gear. For example, the magnetic spur gear coupling can be provided with 4- or 6-pole magnets. Alternatively or additionally, the drive device can be designed as an eddy current drive device or an asynchronous drive.

In a further development, the axial force compensation device can have a corresponding second magnetic spur gear coupling, which is arranged on a side of the magnetized drive gear opposite the magnetic spur gear coupling of the drive device and is set up to counteract a force acting in the axial direction on the magnetized drive gear in front of the magnetic spur gear coupling of the drive device . The second magnetic spur gear coupling can be a free-running or freely rotating rotor. In other words, a free-running magnetic wheel can be provided on the opposite side of the drive gear. The force acting on the drive gear from this free-running magnetic wheel in the axial direction can therefore act on the drive gear in the same amount but with the opposite sign. For example, the magnetic spur gear coupling of the external drive device and the second magnetic standard coupling of the axial force compensation device can be of the same design. As a result, identical parts can be used in production, which simplifies production and reduces costs. Alternatively, a second drive device can be provided on the opposite side of the magnetized drive tooth from the drive device and can act as an axial force compensation device.

The gear pump can be free of a drive shaft protruding from the gear. In other words, the magnetized drive gear has no additional axis which protrudes from the gear. As already explained above, the drive gear can be driven directly and immediately magnetically without a force having to be supplied by means of a shaft connected to the drive gear. An advantage of this embodiment is that it allows for a flat design.

The housing of the gear pump can have a fixed axle pin for the central mounting of the magnetized drive gear. An axis for each of the gears of the gear pump can be permanently integrated in the housing. In particular, the housing and axle can be manufactured in one piece by means of injection molding. The housing may have a top and a bottom. Both the upper side and the lower side can each have a fixed axle pin for the central mounting of the magnetized drive gear. As a result, a mounting of the magnetized drive gear wheel can be provided in a simple and cost-effective manner. The magnetized drive gear can have a central, axial hole for storage. Alternatively, on a top and / or bottom, the magnetized drive gear has a hole for Recording of the or the fixed axle pins can be provided for central storage.

The magnetized drive gear can have one or more magnets integrated in the gear. The drive gear can have several magnets with alternating polarization. Alternating polarization can be understood here as alternating polarization with respect to an axial direction of an axis of rotation of the drive gear. For example, a north-south magnet and a south-north magnet alternate in each case. Power is preferably transmitted by magnets which are arranged in the gear wheel with the greatest possible radial distance from the axis of rotation. As a result, the highest possible torque can be achieved with a given magnet strength. For example, it makes sense to provide an even number of magnets with alternating polarity and a corresponding arrangement on the driving rotor.

The drive gear can consist of a magnetizable material. This enables a particularly efficient production. The drive gear can consist of a magnetizable composite. In particular, the drive gear wheel can be produced from a magnetizable composite by means of injection molding. The drive gear can consist of a magnetizable ferrite-polymer composite. In a particularly preferred embodiment, the pump can be made of plastic by injection molding, the magnetizable gears of a composite consisting of polymer and ferrite or another magnetizable material that can be mixed to form a composite that can be injection molded. One or more advantages of this embodiment, particularly when using a ferrite-polymer composite, can be that low friction, low wear and a long service life can be achieved, the gear pump or the drive gear can be produced inexpensively and/or without problems are disposable.

According to a further aspect of the present disclosure, a gear pump for conveying a liquid medium is proposed, having a housing with an inlet and an outlet, and a magnetized drive gear arranged in the housing for conveying the liquid medium from the inlet to the outlet, the gear pump being set up for this purpose that the drive gear can be driven magnetically and through-free by an external drive device; wherein the drive gear consists of a magnetizable material, in particular a magnetizable composite, in particular a magnetizable ferrite-polymer composite. The axial force compensation device can be an optional feature.

The housing can be made of a non-conductive material, in particular a graphite-filled polyamide composite. For example, the housing can be made of graphite-filled polyamide composite. An advantage of a housing made of a non-conductive material is that eddy current losses that occur with housings made of conductive material can be avoided. An advantage of a housing made of a graphite-filled polyamide composite is that advantageous tribological properties and/or reduced friction can be achieved in the housing of the gear pump with the running gear.

The housing of the gear pump can have a housing upper part and a housing lower part. The housing of the gear pump can consist of an upper housing part and a lower housing part. The upper part of the housing and the lower part of the housing can be identical. Since no bushing is required for a drive axle of the drive gear wheel, the upper part of the housing and the lower part of the housing can be of the same design. Alternatively or additionally, the upper part of the housing and the lower part of the housing can be designed symmetrically. As a result, the manufacturing costs can be reduced. For example, only one mold is required for injection molding the upper and lower parts. A seal can be provided between the upper part of the housing and the lower part of the housing.

In a further development, the upper part of the housing and the lower part of the housing can be connected to one another by gluing. The upper part of the housing and the lower part of the housing can rest against one another at adhesive-free, defined contact surfaces. The adhesive surfaces can be set back from the defined contact surfaces. A resulting gap between the adhesive surfaces can be filled with adhesive and produce a connection between the upper housing part and the lower housing part. Due to the fact that the upper part of the housing and the lower part of the housing of the gear pump rest against one another at defined contact surfaces, precise manufacture is possible at low costs at the same time. The play provided by the defined contact surfaces also avoids fluidic shunts. There is preferably only a minimal play of, for example, less than 50 μm, preferably less than 20 μm, between gears and housing migration.

A housing surface against which the driven gear bears can be provided with a friction-reducing coating. For example, a Teflon coating can be used here. However, there are other coatings ments with a low coefficient of friction and high abrasion resistance are possible. As a result, the efficiency and service life can be further improved.

The housing can have a (maximum) wall thickness of less than 5 mm, in particular less than 2 mm, in particular less than 1 mm. This allows a correspondingly small distance between the drive gear and the drive device. This is advantageous because of the increasing magnetic force effect and increasing torque as the distance decreases.

The height of the gear pump in the axial direction along an axis of rotation of the magnetized drive gear can be less than or equal to 15 mm, in particular less than or equal to 12 mm, in particular less than or equal to 10 mm, in particular less than or equal to 8 mm, in particular less than or equal to 5 mm. A height of the gear pump in the axial direction along an axis of rotation of the magnetized drive gear can be less than or equal to three times the thickness (height in the axial direction) of the magnetized drive gear, in particular less than or equal to twice the thickness of the magnetized drive gear, in particular less than or equal to a 1.5 times the thickness of the magnetized drive gear. An advantage of the respective configurations is a particularly flat design. A particularly flat design can be provided in particular because the magnetic gear wheel can be driven directly.

The housing of the gear pump can have a cylindrical indentation. The magnetized drive gear wheel can be in the form of an annular gear wheel which rotates around the cylindrical concavity. The cylindrical indentation can be designed so that the magnetic, ring-shaped gear wheel can be driven by a magnetic spur gear coupling of an external drive device projecting into the cylindrical recess. With this configuration, an alternative form of the axial force compensation device can be provided. The magnetization of the magnetized drive gear can be provided in the radial direction and a corresponding radial magnetization of the magnetic standard coupling of the external drive device can be provided.

The gear pump can be a medical gear pump. In particular, the gear pump can be designed to deliver an infusion solution or a body fluid.

Further advantages result from the description and the accompanying drawings.

It goes without saying that the features mentioned above and those still to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

• 1 A und B zeigen schematische Darstellungen einer Zahnradpumpe in geschlossenem Zustand und in offenem Zustand ohne Gehäuseoberteil;
• 2 A bis C zeigen perspektivische schematische Darstellungen einer Zahnradpumpe;
• 3 zeigt eine schematische Darstellung eines Pumpsystems mit Zahnradpumpe, Antriebseinrichtung und Axialkraftkompensationseinrichtung;
• 4 zeigt eine Draufsicht einer Antriebseinrichtung mit Stirnradkupplung;
• 5 zeigt eine schematische Darstellung einer magnetisch gekoppelten Zahnradpumpe in Verbindung mit einer Axialkraftkompensationseinrichtung;
• 6 zeigt eine weitere schematische Darstellung einer magnetisch gekoppelten Zahnradpumpe in Verbindung mit einer Axialkraftkompensationseinrichtung;
• 7 zeigt eine weitere schematische Darstellung einer Zahnradpumpe mit Axialkraftkompensationseinrichtung;
• 8 zeigt eine Draufsicht einer schematischen Darstellung einer Zahnradpumpe mit Axialkraftkompensationseinrichtung;
• 9A und B zeigen weitere schematische Darstellungen einer Zahnradpumpe und einer Antriebseinrichtung;
• 10 zeigt eine schematische Darstellung eines Pumpsystems;
• 11 zeigt Fotos von einer mittels Spritzgießen hergestellten Zahnradpumpe und eines magnetisierten Antriebszahnrads;
• 12 zeigt einen Graphen einer Fördermenge über einer Umdrehungszahl einer Zahnradpumpe;
• 13 zeigt eine schematische Darstellung eines Kühlsystems mit einem Kühlpad und einer Kühlvorrichtung;
• 14 zeigt eine schematische Darstellung einer Anwendung des Systems aus 13,
• 15 zeigt den inneren Aufbau des Kühlsystems mit Kühlpad und Kühlvorrichtung aus 13.

Exemplary embodiments of the invention are shown in the accompanying drawings and are explained in more detail in the following description.

• 1A and B show schematic representations of a gear pump in the closed state and in the open state without the upper housing part;
• 2 A until C show perspective schematic representations of a gear pump;
• 3 shows a schematic representation of a pumping system with gear pump, drive device and axial force compensation device;
• 4 shows a top view of a drive device with a spur gear coupling;
• 5 shows a schematic representation of a magnetically coupled gear pump in connection with an axial force compensation device;
• 6 shows a further schematic representation of a magnetically coupled gear pump in connection with an axial force compensation device;
• 7 shows a further schematic representation of a gear pump with an axial force compensation device;
• 8th shows a plan view of a schematic representation of a gear pump with an axial force compensation device;
• 9A B and B show further schematic representations of a gear pump and a drive device;
• 10 shows a schematic representation of a pumping system;
• 11 Figure 12 shows photographs of an injection molded gear pump and magnetized drive gear;
• 12 shows a graph of a delivery rate versus a number of revolutions of a gear pump;
• 13 shows a schematic representation of a cooling system with a cooling pad and a cooling device;
• 14 FIG. 12 shows a schematic representation of an application of the system from FIG 13 ,
• 15 shows the internal structure of the cooling system with cooling pad and cooling device 13 .

1A shows a schematic representation of a plan view of a gear pump 50 in the closed state. 1 B shows a schematic representation of the gear pump 50 in the open state without the upper housing part. The gear pump is set up to convey a liquid medium. 2A shows a perspective view of the gear pump 50 in the closed state. 2 B shows a perspective view of the gear pump 50 without the upper housing part 522. 2C shows a perspective view of gear pump 50 without upper housing part 522 and without gears.

The gear pump 50 has a housing 510 with an inlet 511 and an outlet 512 . A drive gear 531 is arranged in the housing 510 for conveying the liquid medium from the inlet 511 to the outlet 512. In the non-limiting exemplary embodiment shown, the gear pump is designed as an external gear pump, but it can also be an internal gear pump, gerotor pump or screw pump. The gear pump 50 is set up so that the drive gear 531 can be driven magnetically and in particular without a feedthrough by an external drive device. As in 1 B and 2 B shown, the gear pump 50 may have two meshing gears 531,532. Optionally, a first groove or recess 513 can be provided within the housing 510 in an inlet area. Alternatively or additionally, a second groove or depression 514 can be provided in an outlet area of the housing 510 in front of the outlet 512 . In this way, a pressure equalization can be provided and any pressure fluctuations during the conveyance through the gear wheels can be counteracted.

As in 1B shown schematically, the magnetized drive gear can have one or more magnets 533 integrated in the gear. In the example shown, four magnets are provided in the gear, the magnets having an alternating polarization. For example, in the in 1B horizontally opposed magnets 533, a south pole in the axial direction of the axis of rotation of the drive gear 531 upwards and a north pole downwards. Accordingly, with the in 1B vertically opposite magnets 533 point a north pole up and a south pole down.

in the in 2A until 2C shown example, the drive gear 531 also consist of a magnetizable material such as a magnetizable ferrite-polymer composite. The gears can be manufactured inexpensively in large numbers by injection molding. Since the gears are made of magnetizable material, a desired magnetization can be impressed during production. Subsequent magnetization is also conceivable. In this way, a corresponding gear pump can also subsequently be flexibly adapted for drive devices with different magnet arrangements. The housing 510 can consist entirely or partially of a non-conductive material, in particular of a graphite-filled polyamide composite.

in the in 2A until 2C In the example shown, the housing 510 of the gear pump 50 can have an upper housing part 522 and a lower housing part 521 . The upper housing part 522 and the lower housing part 521 are identical in the example shown. The two housing halves can be irreversibly and tightly connected to one another by gluing. The upper housing part 522 and the lower housing part 521 rest against one another at defined contact surfaces 524 . This ensures high precision in production. In particular, fluid shunts, such as overflow or underflow of the gears 531, 532, can be reduced. The adhesive surfaces 525 are set back compared to the adhesive-free contact surfaces 524. Optionally, a groove adjacent to the adhesive surfaces can be provided to accommodate excess adhesive. The adhesive-free contact surfaces are preferably arranged on the inside and the adhesive surfaces are arranged further on the outside. This further reduces the risk that a medium to be transported could come into contact with adhesive.

Optional guide pins 526 and corresponding guide holes 527 aid in aligning the top 522 and bottom 521 housings relative to one another and facilitating assembly. A housing surface 528 against which the driven gear 531 bears can be provided with a friction-reducing, preferably chemically inert, coating. As in 2C shown, the housing 510 may have a stationary axle pin 529 for central mounting of the magnetized drive gear 531. The gear wheel 531 can have a corresponding recess or bore 529 for receiving the axle pin 529. This applies correspondingly to the second gear wheel 532. An axial force compensation device can be optionally provided. The gear pump described above can also be used with a drive device, with the axial force compensation device being part of the drive device.

3 shows a pump system 2 with a gear pump 50 for conveying a liquid medium, a drive device 90 and an axial force compensation device 1501. The gear pump 50 can be a gear pump, as described above with reference to FIG 1 AB and 2A-C described. In 3 a sectional view is shown. A corresponding section plane is exemplified by the characters AA in 1B and 2A implied. The gear pump has a housing with an inlet and an outlet and a magnetized drive gear wheel 531 arranged in the housing for conveying the liquid medium from the inlet to the outlet. The gear pump 50 is set up in such a way that the drive gear 531 can be driven magnetically and without a passage by the external drive device 90 . The axial force compensation device 1501 is set up to counteract a force acting in the axial direction from the drive device 90 on the magnetized drive gear wheel 531 . The force acting from the drive device 90 on the magnetized drive gear wheel 531 is represented by reference number 99 . A counterforce provided by the axial force compensation device is shown with reference number 1512 . The axial force compensation device 1501 can be part of the gear pump 50 or part of the drive device 90 .

in the in 3 example shown, the drive device 90 has a motor 91 and a magnetic spur gear coupling 92 . The magnetic spur gear coupling 92 can have one or more magnets 93 in order to drive the drive gear 531 of the gear pump 50 magnetically and without a bushing. Preferably, the spur gear coupling 92 and the drive gear 531 have corresponding magnets 93, 533 or a corresponding magnetization.

in the in 3 In the example shown, axial force compensation device 1501 has a corresponding second magnetic spur gear coupling 1502, which is arranged on the opposite side of magnetic spur gear coupling 92 of drive device 90 of magnetized drive gear 531 and is set up to engage the magnetized drive gear one in front of magnetic spur gear coupling 92 of drive device 90 531 to counteract force 99 acting in the axial direction, as represented by arrow 1512. The second magnetic spur gear coupling 1502 can be a free-running magnet wheel or a free-running rotor, which moves freely with the driven gear wheel 531 without its own drive. It may seem absurd at first glance that the drive device 90 now has to drive another element in addition to the drive gear wheel 531 . However, the inventors have recognized that the energy to be expended for this can be overcompensated for, since friction losses of the drive gear wheel 531 in the gear pump 50 are reduced. This applies in particular to gear pumps with a simple structure without complex storage of the drive gear 531. The proposed solution makes it possible for the gear pump 50 to be manufactured inexpensively, for example as a disposable item for medical applications.

4 shows a plan view of a drive device 90 with a motor 91, a magnetic spur gear coupling 92 with a plurality of magnets 93. For example, corresponding to the illustration in 1B four magnets with alternating polarizations can be provided.

5 and 6 show perspective representations of a system with drive device 90, gear pump 50 and axial force compensation device. while showing 5 an exploded perspective view and 6 an assembled system. The system off 6 can for example be part of a cooling system 1, as follows with reference to FIG 13 until 15 described.

7 until 9 show another example of a gear pump 50 and an axial force compensation device 1501. The gear pump 50 can be constructed essentially as described above. In the following, the differences will be discussed in particular. Deviating from the exemplary embodiments described above, the housing 510 can have a cylindrical indentation 542 . In this example, the magnetized drive gear wheel 531 is in the form of an annular gear wheel 541 which rotates around the cylindrical indentation 542 . The cylindrical indentation 542 is designed so that the magnetic, ring-shaped gear 541 can be driven by a magnetic spur gear coupling 92 of an external drive device 90 protruding into the cylindrical recess 542 . This arrangement can also represent an axial force compensation device 1501, since the arrangement of the now ring-shaped drive gear 541, which surrounds the cylindrical indentation 542, in which a protruding magnetic spur gear coupling 92 is provided, now causes a radial force transmission. Correspondingly, the magnets 533 are in the magnetized Drive gear ring 542 is aligned in the radial direction and the magnets 93 in the spur gear clutch 92 are also aligned in the radial direction, as shown in FIG 8th shown.

9A and 9B show exemplary perspective representations of the system in connection with a drive device 90.

10 shows a schematic representation of a pumping system 2 which can suck in a liquid medium from a container 3 . The pump system 2 has a base body 701 and a cover 702 . The gear pump 50 can be accommodated between the base body 701 and the cover 702 . In this case, the drive device 90 can be arranged in the base body 701 and the axial force compensation device 1501 can be arranged in the cover 702 . The gear pump 50 can simply be inserted between the cover 702 and the base body 701. In this way, a simple change between different pumps can take place without the need for complex cleaning of the rest of the pump system 2 . In contrast to peristaltic pumps, it is also not necessary to feel a tube system in the squeeze elements of the peristaltic pump, which is time-consuming and error-prone.

The gear pump 50 and the adjoining hose system can preferably already be supplied in a sterile packaging. This avoids contamination and saves valuable laboratory time.

11 shows photographs of an exemplary gear pump 50 as shown in FIG 10 pump system shown could be inserted, as well as an exemplary representation of a corresponding magnetized drive gear the 531.

12 12 shows an example graph of displacement versus RPM of a gear pump for FIG 10 system shown. The horizontal axis denotes the number of revolutions of the drive gear in revolutions per minute. The vertical axis denotes the flow rate in milliliters per minute. How out 12 As can be seen, there is an approximately linear relationship between the flow rate and the number of revolutions over a wide range.

13 shows a schematic representation of a cooling system 1 with a cooling pad 10 and a cooling device 60. The cooling pad 10 can be used in particular for human or veterinary medical purposes. The cooling pad 10 has a first heat exchanger 20 and a second heat exchanger 30 . The first heat exchanger 20 and the second heat exchanger 30 are arranged at a distance from one another and are fluidically connected to one another via a line system 40 . The cooling pad 10 also has a pump device 50 which is set up to bring about an exchange of a heat transport fluid between the first heat exchanger 20 and the second heat exchanger 30 via the line system 40 . The first heat exchanger 20 is also referred to as a bodyside heat exchanger. The second heat exchanger 30 is also referred to as a device-side or cooling-device-side heat exchanger, since it is set up to be accommodated by the cooling device 60 .

The pumping device 50 can preferably be a gear pump, as described above. In particular in the case of a battery-operated cooling system, the efficiency can be further improved thanks to the proposed axial force compensation device.

In the present example, the line system 40 has two hose lines, a feed 41 and a return 42 . The feed 41 is fluidically connected to an inlet 21 of the first heat exchanger 20 and an outlet 32 of the second heat exchanger 30 . The return 42 is fluidically connected to an outlet 22 of the first heat exchanger 20 and an inlet 31 of the second heat exchanger 30 .

The cooling pad 10 can be a fully integrated, closed, fluid-filled cooling pad. The cooling pad 10 can have a hermetically sealed fluid circuit. It is therefore not necessary to connect the cooling pad to an external fluid circuit. This can significantly simplify handling.

The cooling device 60 for human or veterinary medical applications has: a receptacle 61 designed to receive the second, device-side heat exchanger 30 of the cooling pad; a cooling device, in particular with a thermoelectric cooling element such as a Peltier element 81; wherein the cooling device is set up to supply heat to the second, device-side heat exchanger 30 of the cooling pad 10 or to remove heat from it when the heat exchanger of the cooling pad is in the receptacle 61; and a drive device 90 which is set up to drive a pump device 50 integrated in the cooling pad 10 . This is an example in 15 shown.

14 shows a schematic representation of a cooling system 1 with a cooling pad 10, a cooling device 60 and, in addition, an orthosis 70. The device-side second heat exchanger with the integrated pump device 50 becomes a receptacle 61 of the cooling device is inserted. The orthosis 70 can be a conventional orthosis. 14 shows a user 100 with an exemplary knee orthosis 70. A thickness or overall height of the first heat exchanger 20 is preferably selected such that the heat exchanger can be worn under an orthosis 70. As in 14 shown, the line system 40 now leads from the first heat exchanger 20 carried under the orthosis 70 to the cooling device 60. The cooling device 60 is preferably a battery-operated cooling device which can be used mobile and independently of other cooling infrastructure. For example, the cooling device 60 can be carried with a shoulder strap 66 . Alternatively, depending on the cooling capacity required, smaller units can also be provided, which can be worn, for example, on the belt or directly on clothing or on the body.

15 shows a schematic representation of an internal structure of a cooling device 60 with a device-side heat exchanger 30. For example, it can be a cooling device 60 as in FIG 13 shown.

in the in 15 example shown, the cooling device can have one or more electrically operated Peltier element(s) 81 which is arranged on an upper side of the receptacle 61 . Alternatively or additionally, the cooling device can have one or more electrically operated Peltier element(s) 81`, which is arranged on the underside of the receptacle 61. The electrically operated Peltier element 81 or the electrically operated Peltier elements 81, 81' use the second heat exchanger 30 to regulate the temperature of the heat transport fluid circulated by the pump device 50 in the fluid circuit of the cooling pad. The waste heat, ie the heat taken from the heat transport fluid plus the electrical power of the Peltier element 81, can be dissipated via one or more heat sinks (not shown) and optionally one or more fans 84, 84'. The heat transport fluid 11, which has now been cooled to a target temperature, is transported via the closed fluid circuit to the first heat exchanger 20 resting on an area of skin and absorbs heat there, so that the area of skin is cooled as desired. As mentioned at the outset, the system can also be used to heat desired areas of skin by supplying heat to the areas of skin by means of the heat transport fluid 11 .

in the in 15 In the example shown, a film covering the cooling pad 30 and an upper side of the pump device 50 are not shown in order to show the internal structure of the cooling device 60 and the heat exchanger 30 . When pushed in, the device-side heat exchanger 30 with the integrated pump device 50 comes to rest in the receptacle 61 of the cooling device in such a way that a gear wheel 95 of the gear pump comes to rest under a drive device 90 for the pump device 50 . The pump device 50 is designed to be driven by the drive device 90 without a passage.

in the in 15 example shown, the axial force compensation device can be part of the drive device. The drive device 90 can have a magnetic spur gear coupling on a first side of the heat exchanger 30 for driving the pump device 50 . An axial force compensation device can be provided on an opposite second side of the heat exchanger 30 with the pump device 50 (not shown in the perspective view), the axial force compensation device being designed to act one of a magnetic spur gear coupling axially along an axis of rotation of a gear 95 of the gear pump 50 counteract the force.

The present disclosure is particularly concerned with an improved gear pump, an improved drive device and a corresponding pumping system. The solutions disclosed herein can be used to particular advantage in medical engineering reports and laboratory applications. In particular, the solutions disclosed herein can represent an alternative to the peristaltic pumps that are often used in the field of medical technology and/or alleviate the existing disadvantages of gear pumps.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102018105674 B3 [0004, 0013]

Claims (22)

Gear pump (50) for conveying a liquid medium, with: - a housing (510) with an inlet (511) and an outlet (512), and - a magnetized drive gear (531) arranged in the housing for conveying the liquid medium from the inlet (511) to the outlet (512), the gear pump being set up so that the drive gear (531) can be driven magnetically and without a passage by an external drive device (90). is; wherein the gear pump also has an axial force compensation device (1501) which is set up to counteract a force acting in the axial direction from the external drive device (90) on the magnetized drive gear wheel (531). gear pump after claim 1 , wherein the gear pump (50) is set up to be driven by the external drive device (90) by means of a magnetic spur gear coupling (92). gear pump after claim 2 , wherein the axial force compensation device (1501) has a corresponding second magnetic spur gear coupling (1502), which is arranged on a side of the magnetized drive gear wheel (531) opposite the magnetic spur gear coupling (92) of the drive device (90) and is set up to move one in front of the magnetic Spur gear coupling (92) of the drive device (90) to counteract the force acting on the magnetized drive gear (531) in the axial direction. gear pump after claim 3 , wherein the second magnetic spur gear coupling (1502) is a freely rotating rotor. A gear pump according to any one of the preceding claims, wherein the gear pump (50) is free of a drive shaft protruding from the drive gear (531). Gear pump according to one of the preceding claims, wherein the housing (510) has a fixed axle pin (529) for the central mounting of the magnetized drive gear (531). Gear pump according to one of the preceding claims, in which the magnetized drive gear (531) has one or more magnets (533) integrated in the gear. gear pump after claim 7 , wherein the drive gear (531) has a plurality of magnets (533) with alternating polarization. Gear pump according to one of the preceding claims, in which the drive gear (531) consists of a magnetizable material. gear pump after claim 9 , wherein the drive gear (531) consists of a magnetizable composite and is produced in particular by means of injection molding. gear pump after claim 9 or 10 , wherein the drive gear (531) consists of a magnetizable ferrite-polymer composite. Gear pump according to one of the preceding claims, in which the housing (510) consists of non-conductive material, in particular of a graphite-filled polyamide composite. Gear pump according to one of the preceding claims, wherein the housing (510) of the gear pump (50) has a housing upper part (522) and a housing lower part (521), the housing upper part and housing lower part being identical. gear pump after Claim 13 , wherein the upper housing part (522) and the lower housing part (521) are connected to one another by gluing, the upper housing part and the lower housing part resting against one another on adhesive-free defined contact surfaces (524), with adhesive surfaces (525) being set back compared to the defined contact surfaces (524). Gear pump according to one of the preceding claims, in which a housing surface (528) against which the driven gear (531) bears is provided with a friction-reducing coating. Gear pump according to one of the preceding claims, wherein the housing (510) has a wall thickness of less than 5 mm, in particular less than 2 mm, in particular less than 1 mm. Gear pump according to one of the preceding claims, wherein a height of the gear pump (50) in the axial direction along an axis of rotation of the magnetized drive gear (531) is less than or equal to 15 mm, in particular less than or equal to 12 mm, in particular less than or equal to 10 mm, in particular less than or equal to is equal to 8 mm, in particular less than or equal to 5 mm. Gear pump according to one of the preceding claims, wherein a height of the gear pump (50) in the axial direction along an axis of rotation of the magnetized drive gear (531) less than or equal to three times the thickness of the magnetized drive gear, in particular less than or equal to twice the thickness of the magnetized drive gear, in particular less than or equal to 1.5 times the thickness of the magnetized drive gear is. Gear pump according to one of the preceding claims, wherein the housing (510) has a cylindrical concavity (542), wherein the magnetized drive gear (531) is designed as an annular gear (541) which rotates around the cylindrical concavity (542), and wherein the cylindrical concavity is designed such that the magnetic, ring-shaped gear (541) can be driven by a magnetic spur gear coupling (92) of an external drive device (90) projecting into the cylindrical concavity. A gear pump according to any one of the preceding claims, wherein the gear pump (50) is a medical gear pump. Drive device (90) for a gear pump (50), the gear pump having a magnetized drive gear (531) arranged in a housing (510) of the gear pump for conveying the liquid medium from an inlet (511) to an outlet (512) of the gear pump, wherein the drive means (90) - Has a magnetic spur gear coupling (92) and is set up to drive the drive gear (531) of the gear pump (50) magnetically and through-free; and - An axial force compensation device (1501), which is set up to counteract a force acting in the axial direction from the drive device (90) on the magnetized drive gear wheel (531). Pumping system (2) with - A gear pump (50) for conveying a liquid medium; - a drive device (90); and - An axial force compensation device (1501); wherein the gear pump (50) has a housing (510) with an inlet (511) and an outlet (512), and a magnetized drive gear wheel (531) arranged in the housing for conveying the liquid medium from the inlet to the outlet, wherein the gear pump (50) is set up in such a way that the drive gear (531) can be driven magnetically and without a passage by the drive device (90); wherein the axial force compensation device (1501) is set up to counteract a force acting in the axial direction from the drive device (90) on the magnetized drive gear wheel (531).

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