Coolant pump

Abstract

The invention refers to a coolant pump for feeding a coolant, the pump (2) comprising at least one impeller (12) and an electric drive motor (6) driving this at least one impeller (12), comprising a magnetic coupling (4) between the drive motor (6) and the impeller (12) with at least one first rotatable coupling part connected to a rotor of the drive motor (6), at least one second coupling part (36) connected to the impeller (12) and with a separating wall (24) between the first coupling part (34) and the second coupling part (36), wherein the separating wall (24)hermetically seals a coolant space with the impeller (12) and the second coupling part (36) therein and by at least one heating device arranged to heat at least a portion of the coolant pump to prevent icing.

Description

[0001] Applicant: GRUNDFOS HOLDING A / S

[0002] Title: Coolant pump

[0003] Our Ref.: GP 3844 WO

[0004] Description

[0005]

[0001] The invention refers to a cooling pump for feeding a coolant in a cooling application.

[0006]

[0002] Beside compressors in cooling units or chillers for cooling applications, coolant pumps are used for feeding or circulating a coolant, like for example ammonia. For this applications hermetically sealed pumps are required. For this purpose, pumps with a motor arranged inside the coolant are known.

[0007]

[0003] In view of this prior art it is the object of the invention to provide a more efficient coolant pump.

[0008]

[0004] This object is achieved by a coolant pump having the features defined in claim 1 and the use of such a coolant pump as defined in claim 15. Preferred embodiments are defined in the respective subclaims, the following description and the accompanying figures.

[0009]

[0005] The coolant pump or coolant pump unit according to the invention is configured for feeding a coolant, i.e. it is suitable to feed a coolant with a temperature below zero degrees. The pump comprises at least one impeller. In possible embodiments there may be arranged more than one impeller in several stages to achieve a higher increase in pressure. The at least one impeller or the several impellers are connected to or arranged on a pump shaft for rotatably driving the impellers. Furthermore, the coolant pump comprises an electric drive motor which is driving the at least one impeller. According to the invention there is arranged

[0010] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 a magnetic coupling between the drive motor and the impeller. This magnetic coupling comprises at least one first rotatable coupling part and at least one second rotatable coupling part, wherein in one or both of these coupling parts there are arranged permanent magnets and / or soft magnetic elements to provide a magnetic engagement or magnetic force between the two coupling parts. This allows to rotate the first rotatable coupling part and to transmit this rotational movement and the torque onto the second coupling part via magnetic forces between the first and the second coupling part. The first magnetic coupling part is connected to the drive motor, in particularto an output shaft of the electric drive motor. The second magnetic coupling part is connected to the at least one impeller or the several impellers, preferably via a pump shaft connected to the at least one impeller. The magnetic coupling between the first and the second coupling part allows to have a distance or gap between the first and the second coupling part. In this gap there is located a separating wall such that the first coupling part is on one side of the separating wall and the second coupling part on the other side of the separating wall. The separating wall is arranged such that it hermetically seals a coolant space with the impeller and the second coupling part therein. Thus, the second coupling part is running inside the coolant fed by the impeller, whereas the first coupling part is located on the other side of the separating wall, i.e. on the dry side outside the coolant. This magnetic coupling allows to have the entire drive motor outside the cooling, in dry conditions. This allows to use a conventional dry running electric drive motor for driving the coolant pump which allows to use a high efficiency drive motor, thereby improving the efficiency of the entire coolant pump. By the separating wall the coolant or the space containing the coolant inside the pump can be hermetically sealed to the outside without the need of a shaft sealing. This allows to securely prevent leakage of the coolant, which for example in case of a ammonia may be harmful.

[0011] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025

[0006] Furthermore, the coolant pump comprises at least one heating device which is arranged to heat at least apportion of the coolant pump, for example a portion of the pump structure or pump housing, to prevent icing. Icing on the pump structure may block movable parts of the pump, for example a movable part of the magnetic coupling. By the heating device those parts that have a risk of icing can be heated to prevent the icing.

[0012]

[0007] The electric drive motor may be an electronically controlled drive motor. Preferably this drive motor comprises a speed control and further preferably a frequency convertor for regulating and controlling the drive speed of the drive motor. By such an electronic control of the drive motor it is possible to always run the motor under best efficiency. The control electronics of the drive motor may be arranged in a terminal box or electronics housing located on the outside of a stator housing of the drive motor or may be arranged inside the stator housing of the drive motor. Thus, all necessary control electronics can be arranged directly at or in the electric drive motor without need of external control devices. However, in further embodiments it may be possible to arrange or partly arrange control devices externally, i.e. distanced from the drive motor. Furthermore, the control electronics of the drive motor may have at least one communication interface to interact with an external control device or automation device.

[0013]

[0008] In a further possible embodiment of the invention, the coolant pump comprises at least one heating device which is located and configured to heat a rotating part, in particular the first coupling part, i.e. the coupling part located outside the coolant. The rotating part, in particular the first coupling part may be heated directly or indirectly. Additionally or alternatively, the heating device may be configured and arranged to heat the surroundings of the rotating part, in particular the first coupling part, and / or to heat at least one portion of a stationary part, like for example the separating wall, or to heat at least one element connected

[0014] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 to said stationary part or separating wall, respectively. In a further alternative or additional option, the heating device may be configured and located to heat at least a part of a pump housing. Generally, the heating device may be arranged at any suitable location in the surroundings of the rotating part, in particular of the first coupling part, or at or in the rotating part, preferably the first coupling part, allowing to heat the surroundings of this rotating part. By heating the rotating part, in particular the first coupling part, or the surroundings of this rotating part icing or the formation of ice in the surroundings of this rotating part can be prevented. Due to the humidity in the surroundings, water may condense on the cold parts of the pump housing and in particular on the outer, i.e. dry side of the separating wall. Since the coolant inside the pump usually is below zero degrees Celsius, for example in a temperature range of zero to -40 degrees Celsius, the condensing water may freeze so that ice may grow on the outside of the cold parts. If the ice comes into contact with the first coupling part, the first coupling part may be blocked. By the heating device according to the preferred embodiment of the invention the surroundings of the first coupling part are heated such that the formation of ice which may block the rotation of the first coupling part can be prevented. Thus, the heating device allows to use a magnetic coupling between the impeller and the coolant-carrying areas of the pump on one side and the drive motor on the other side without the risk of a failure due to icing on the movable parts of the coupling.

[0015]

[0009] Preferably, at least one element or wall portion heated by the heating device is facing the first coupling part. According to this solution, preferably, those walls or wall portions which are facing the first coupling part are at least partly heated by the heating device to prevent icing in those regions which are close to the first rotating coupling part and in which icing may have the risk to block the rotating coupling part.

[0016]

[0010] In the magnetic coupling, a rotational axis of the first coupling part and a rotational axis of the second coupling part preferably are aligned

[0017] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 with one another. Furthermore, preferably the first coupling part is arranged concentrically to the second coupling part, i.e. surrounding the second coupling part. Thus, there may be magnetic fields acting in circumferential and / or radial direction between the first and the second coupling part. Between the first and the second coupling part there is arranged the separating wall for example in form of a tube or can.

[0018]

[0011] Preferably, said separating wall is a rotor can surrounding the second coupling element, wherein the first coupling part is arranged in the outer circumference of said can, i.e. in the outer circumference of the second coupling part and the first coupling part. In such an embodiment the magnetic field extends through the separating wall which may be a metal wall, a plastic wall or a wall from a composite material. The material of the separating wall has to ensure the hermetical sealing of the space containing the coolant and to withstand the pressure inside this space. The first and / or the second coupling part may be provided with permanent magnets and / or soft magnetic elements to establish a magnetical field, preferably directed in radial direction relating to the rotational axis of the coupling parts. Thereby, the magnets preferably are distributed along the circumference such that the radial forces provided by the magnets onto the coupling parts are compensated. If the separating wall is a rotor can, the rotor can is filled by the coolant and thus, the wall of the rotor can is cold. Therefore, preferably the heating device is arranged on the outside of the rotor can such that the rotor can in the area, where it is cooled from the inner side is heated from the outside to prevent icing on the outside of the rotor can.

[0019]

[0012] In a further possible embodiment, the separating wall, preferably in form of a rotor can, is held on a pump housing by a fastening ring or menacle ring overlapping a flange of the separating wall. If the separating wall is a rotor can this flange may substantially extend transverse or normal to the longitudinal axis of the can which is coincident with the rotational axis of the coupling parts arranged inside and outside of the

[0020] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 can. In such configuration the can is clamped or pressed in axial direction along this longitudinal axis against a contact surface on the pump housing containing the at least one impeller. The axial end of the can comprising the flange is close to the interior of the pump housing containing the impeller and the cold coolant pumped by the impeller. Thus, this axial end is the coldest end of the can during operation of the pump. Therefore, according to a preferred embodiment the heating device is in contact with the fastening ring or menacle ring as described before. The flange and the menacle ring may in particular face the axial end of the outer coupling part, i.e. the first coupling part. Thus, there may be the risk of icing on this outer side of the flange or menacle ring towards the axial end side of the magnetic coupling part. By arranging the heating device on the fastening ring, thus, the coldest parts facing the first coupling part can be heated to prevent the icing.

[0021]

[0013] The heating device preferably is an electric heating device and further preferably comprises a temperature control. By a temperature control in particular an overheating can be prevented. The permanent magnets in the magnetic coupling may be heat-sensitive or may be affected by heat. Thus, it is desired to keep the temperature provided by the heating device below a threshold temperature above which the permanent magnets may be damaged.

[0022]

[0014] For the temperature control the heating device may comprise at least one temperature sensor which preferably is arranged to detect a temperature of the heating device in a region close to the first coupling part. In a further possible embodiment, at least one temperature sensor may be integrated into the heating device or a heating unit of the heating device, directly detecting the temperature at the heat source. By this, a precise and reliable temperature control is possible. A temperature control may be carried out by just switching on and off the heating device to keep the temperature below a threshold as mentioned above. Furthermore, it may be possible to provide a heat regulation for example

[0023] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 by controlling the current in on electric heating element. The at least one temperature sensor should be located such that by its temperature measurement the temperature applied to the first coupling part can be controlled to ensure that the first coupling part is not overheated or damaged by heat.

[0024]

[0015] For the control of the heating device the coolant pump may have a temperature controller, i.e. temperature control electronics which preferably are connected to the at least one temperature sensor described before and to at least one heating element or heating unit, such that the heating element or heating unit, preferably an electric heating element, can be controlled dependent on the signal received from the at least one temperature sensor. In a special embodiment, the temperature control may be carried out in the control electronics of the drive motor. In such embodiment, the at least one heating device, in particular a heating element or a heating unit, is connected to the control electronics of the drive motor. Furthermore, preferably the at least one temperature sensor described before is also connected to the control electronics of the drive motor. The control electronics may comprise necessary electronic components like a microprocessor, storage means, electronic switching elements, etc. In such an embodiment, a temperature control of the heating device, in particular dependent on the signals of at least one temperature sensor, may be performed by the control electronics of the drive motor, preferably a software module in the control software of the drive motor. This allows to provide an integrated motor control controlling both the drive motor, in particular the speed of the electric drive motor, and the temperature of the heating device in the coupling between the motor and the pump. Thus, all necessary control electronics for controlling the entire pump unit may be integrated into the motor control, preferably arranged in a single electronics housing on the stator housing of the drive motor.

[0025] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025

[0016] In a further possible embodiment, the heating device may comprise at least one heating unit made from a plastic material, like for example silicone, and having heating elements embedded into this plastic material, for example in a moulding process. The heating elements may be electrical heating wires embedded into the plastic material which serves as an insulating material for the electrical insulation and protects the heating elements. The heating unit preferably may be a flat heating mat or heating pad which can be applied onto the surface of a housing part or portion of the separating wall for heating. Such a pad may have a very low height allowing to be arranged close to the coupling part without increasing the space needed for the magnetic coupling.

[0026]

[0017] In a preferred embodiment, the heating device comprises at least one heating unit, preferably a heating pad which is attached to the separating wall, in particular a rotor can, and / or a heat conducting element connected to said separating wall or can. This allows to directly or indirectly heat the outside of those elements on which an icing may occur, because of the cooling from the coolant.

[0027]

[0018] In a further possible embodiment which may be realized as an alternative or in combination to the embodiment described before the heating device comprises at least one heating unit, which heating unit at least partly surrounds said separating wall and the first rotatable coupling part. Such a heating unit may have the shape of a tube or collar surrounding the first rotatable coupling part and allows to warm or heat the coupling part from the outside. Thereby the heating unit is distanced from the first rotatable coupling part so that the coupling part can freely rotate. The heating unit surrounding said separating wall and the coupling part may be a heat conductive element conducting and transmitting heat from a heating unit comprising heating elements, for example a heating pad as described in the following. Alternatively or additionally, said heating unit which at least partly surrounds said separating wall and

[0028] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 the first rotatable coupling part may comprise at least one heating element, i.e. an active heating element producing heat, preferably an electric heating element. This heating element may be a heating wire or cable extending along a surface of a tube-shaped heating unit or may be integrated into a wall of the heating unit, which wall surrounds said rotatable coupling part. A wall surrounding the first rotatable coupling part for heating may be a wall made from plastic or metallic material. A heating element may be integrated into the wall by injection molding. In an alternative embodiment the wall may comprise holders our carrier elements carrying a heating cable or heating wire on the inner and / or outer side of the wall.

[0029]

[0019] In a further possible embodiment, the heating device comprises a heating unit in form of a heating mat or heating pad which is attached to a surface of a fastening ring or a menacle ring of the rotor can as described above. Such a heating pad may for example have a circular shape extending along the entire circumference of such a fastening or menacle ring so that the fastening ring may be heated over its entire circumference to prevent icing on this fastening ring. The heating pad may be made from plastic material, for example silicone, as described before. It may be glued onto the outer surface of the fastening ring, which preferably is a surface extending transverse to the rotational axis of the impeller and the coupling, i.e. is the surface facing the axial end of the outer coupling part, which may be the first coupling part described before.

[0030]

[0020] In a further possible embodiment, the heating pad on its surface facing away from the fastening ring may at least partly be covered by a retaining element. This retaining element may be a metal element made from sheet metal. The retaining element holds the heating pad or heating element on the surface of the fastening ring, in particular in a heat conducting attachment. A retaining or fastening element made from

[0031] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 metal may further improve the distribution of heat provided by the heating device, in particular a heating pad. The retaining element preferably is secured to the fastening ring by screws or bolts, which are the bolts used for clamping the fastening ring on a pump housing. Thus, the retaining element can be securely attached to the pump housing with the same screws used for fastening the fastening ring.

[0032]

[0021] In a further possible embodiment a heating pad as described before may be thermally connected to a heat-transmitting element or a heating unit, which heat-transmitting element or heating unit at least partly surrounds said separating wall and the first rotatable coupling part. The heat-transmitting element may be a heat conducting wall connected to the heating pad and conducting the heat produced in the heating pad. The heat-transmitting element or heating unit may be a passive element conducting and transmitting heat. In a further possible embodiment the heating unit surrounding said separating wall and the first rotatable coupling part may comprise at least one heating element, in particular an electric heating element. In a further possible embodiment both the heating pad and the heating unit surrounding the rotatable coupling part each comprise at least one heating element, preferably electrical heating elements. The heating elements of the heating pad and the heating unit surrounding said rotatable coupling part, may be electrically connected, for example connected in parallel or in series so that they can be controlled together by a single control device.

[0033]

[0022] Beside the cooling pump described above, the use of such a cooling pump in a cooling applications is subject of the present invention. The cooling application may comprise at least one piping system in which a coolant, for example ammonia is circulated. The cooling pump is arranged in such a cooling circuit, preferably in addition to a cooling compressor or chiller connected to the circuit. The cooling pump is used for pumping the coolant which has a temperature below zero degrees, further preferably below -10 degrees. By the configuration of the cooling

[0034] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 pump as described above, a high efficiency is ensured. Concerning preferred embodiments of the use of the cooling pump it is referred to the above-mentioned description.

[0035]

[0023] In the following, the invention is described byway of example with reference to the accompanying drawings. In these:

[0036] Fig. 1 schematically shows a coolant pump according to the invention,

[0037] Fig. 2 shows an enlarged cross section of the pump and the coupling of the coolant pump according to figure 1 ,

[0038] Fig. 3 schematically shows a heating pad used in the cooling pump according to figures 1 and 2,

[0039] Fig. 4 shows a perspective view of a fastening ring with the heating pad according to figure 3 applied,

[0040] Fig. 5 shows a cross section of a coupling of the cooling pump according to a second embodiment of the invention,

[0041] Fig. 6 schematically shows the heating unit used in the cooling pump according to figure 5, and

[0042] Fig. 7 shows a cross section of the heating unit according to figure 6.

[0043]

[0024] The coolant pump unit shown in figure 1 has three essential parts, a pump 2, a magnetic coupling 4 and an electrical drive motor 6. The magnetic coupling 4 is configured to transmit a torque from the output shaft 7 of the motor 6 to the pump 2. The electric drive motor 6 is a dry running electric drive motor with an electronic motor control having a

[0044] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 frequency convertor for controlling and regulating the rotational speed of the drive motor 6. The motor control, i.e. the respective control electronics 8 are arranged inside an electronics housing 10 on the outer side of the drive motor 6.

[0045]

[0025] In this example, the pump 2 is a four-stage pump having four impellers 12 arranged in series on a common pump shaft 14. The pump housing 16 in this example comprises a bottom portion 17 having an inlet 18 and an outlet 20. Furthermore, the pump housing 18 comprises an upper portion 22 and a cylindrical wall 24 arranged between the bottom portion 17 and the upper portion 22 and surrounding the impellers 12. In the figures shown, the bottom part 22 is arranged on the lower axial end of the pump unit, seen along the rotational axis x. However, it has to be understood that the pump may be used in a different orientation, for example with the rotation axis arranged horizontally. In this case, the bottom portion 17 would be arranged on one axial end along the horizontal axis and the upper portion 22 would be distanced horizontally.

[0046]

[0026] The upper portion 22 of the pump housing 16 is the portion adjacent to the magnetic coupling 4. A part of the magnetic coupling 4 is connected to this upper portion 22. As can be seen in the enlarged view in figure 2, the upper portion 22 comprises a central opening 26 through which the pump shaft 14 extends into the magnetic coupling 4. The opening 26 is closed by a separating wall in form of a rotor can 28 which is cup-shaped and comprises a flange 30 at its open axial end, seen along the rotational axis x of the shaft 14. The flange 30 extends radially outwardly from the cylindrical rotor can 28 and is attached to a support surface surrounding the opening 26. The flange 30 is clamped between the axial end surface of the upper portion 22 surrounding the opening 26 and a fastening ring or menacle ring 32, respectively.

[0047]

[0027] The second axial end of the rotor can 28 is closed. Between its two axial ends the rotor can 38 has a cylindrical shape with an inner space

[0048] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 open towards the interior of the pump housing 16, i.e. connected to the space containing the coolant to be pumped. The cylindrical portion of the rotor can 28 extends concentrically about the rotational axis x and separates two parts of the magnetic coupling 4, a first coupling part 34 and a second coupling part 36. Both coupling parts 34 and 36 of the magnetic coupling 4 are rotatable about the rotational axis x and are arranged concentrically to one another. The first coupling part 34 is arranged in the outer circumference of the cylindrical portion of the rotor can 28 and the second coupling part 36 is arranged inside the rotor can 28. Thus, the second coupling part 36 rotates inside the inner space of the rotor can 28 which is filled by the coolant, whereas the first coupling part 34 is arranged in the dry outside the rotor can 28. The inner, second coupling part 36 is fixed to the rotor shaft 14 to transmit a torque to this shaft 14 to drive the impellers 12. The first, outer coupling part 34 is connected to the output shaft 7 of the drive motor 6, as shown in figure 1. The first coupling part 34 and the second coupling part 36 both contain permanent magnetic elements which are facing in radial direction to provide a magnetic force between the first coupling part 34 and the second coupling part 36 allowing to transmit a torque from the first coupling part 34 to the second coupling part 36 with the rotor can 28 between the two coupling parts 34 and 36.

[0049]

[0028] Since the interior of the pump housing 16 and the rotor can 28 is filled by the coolant, the rotor can 28 and in particular the axial end of the rotor can 28 attached to the upper portion 22 of the pump housing 16 are cooled. Therefore, also the metallic fastening ring 32 gets cold so that there is a risk of icing on the outside of the rotor can 28 and on the outside of the fastening ring 32, due to the humidity in the surrounding air. Ice growing on the fastening ring 32 or at the lower end of the rotor can 28 may come into contact with the first coupling part 34 and block the first coupling part 34. To prevent this, there is provided a heating device on the fastening ring 32. The heating device comprises a heating

[0050] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 pad 38 which is attached or glued onto the axial surface of the fastening ring 32 which faces the axial end side of the first coupling part 34. The heating pad 38 is electrically heated so that the fastening ring 32 and the axial end of the rotor can 28 adjacent to the pump housing 16 are heated to prevent icing on the outside of these elements.

[0051]

[0029] The heating pad 38 is described in more detail with reference to the figures 3 and 4. The heating pad 38 is made from plastic material like silicone and comprises embedded heating elements in form of electric heating wires 40. These heating wires 40 are embedded into the plastic material of the heating pad 38 by moulding and are connected to a power cable 42. Furthermore, there is a temperature sensor 44 attached to or incorporated into the heating pad 38 for detecting the temperature of the heating pad 38. The heating pad 38 has a circular shape adapted to the shape of the fastening ring 32 and may comprise a gap 46 allowing to attach the heating pad 38 to the fastening ring 32 without disassembling the magnetic coupling 4.

[0052]

[0030] Figure 4 shows heating pad 38 attached to the axial face side of the fastening ring 32. The heating pad 38 may be attached to the fastening 32 by glueing. Alternatively or additionally, the heating pad 38 is fixed by a fastening or retaining element 48. The retaining element 48 is a flat metal ring from sheet metal. The retaining element 48 is attached to the upper side of the heating pad 38, i.e. the axial side opposite to the fastening ring 32, as seen along the rotational axis x. The retaining element 48 is fastened on the fastening ring 32 by clips 50 (only one shown in figure 4). The clip 50 has one or more yokes or holding elements 52, respectively, which are in contact with the axial surface of the retaining element 48 opposite to the heating pad 38. In an alternative embodiment, the clips 50 may be integrally formed with the protective element 48 or fixed to the retaining element 48, for example, by welding. The clip 50, furthermore, has a lug 54 extending radial inward such that it lies on the fastening ring 32 surrounding a fastening hole 56 in the fastening ring

[0053] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 32. The lug 54, thus, has an opening which is aligned with the fastening hole 56 in the fastening ring 32. This allows that the fastening bolts 58 for clamping the fastening ring 32 on the upper portion 22 of the pump housing 16 extend through the lugs 54 and the fastening holes 56, to clamp, both, the fastening ring 32 and the retaining element 48.

[0054]

[0031] The power cable 42 and the temperature sensor 44 are connected to the control electronics 8 inside the electronics housing 10 of the drive motor 6 by at least one cable 60. The control electronics 8 of the motor control inside the electronics housing 10 additionally perform a temperature control of the heating pad 38. Thus, via the power cable 42 the heating pad 38 is activated or controlled depending on the signals from the temperature sensor 44. This temperature control ensures that the temperature of the heating pad 38 stays below an upper threshold, for example 100 or 120 degree Celsius. Higher temperatures may damage the permanent magnets inside the magnetic coupling 4, in particular in the first coupling part 34. By the temperature control too high temperatures are prevented. The integration of the temperature control into the control electronics 8 of the drive motor 6 provides an integrated control of the entire pump unit without the need of separate electronics for the temperature control. However, it would be possible to have a separate temperature control in addition to the control electronics 8 of the drive motor 6.

[0055]

[0032] Figures 5 to 7 show a second embodiment according to the invention. According to this second embodiment in addition to the heating pad 38 as described above there is provided a further heating unit 62 surrounding the first, outer coupling part 34. The heating unit 62 comprises a circular wall 64 radially distanced and concentric to the rotor can 28 and the first coupling part 34. In this embodiment the wall 64 extends in axial direction X from the retaining element 48. In this embodiment the retaining element 48 is unitary formed with the wall 64, for example from plastic or metallic material. Also, in the second embodiment

[0056] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 the retaining element 48 is arranged on top of the heating pad 38 as described in the first embodiment. Thus, there may be a heat transfer from the heating pad 38 towards the wall 64. On the inner circumferential side of the wall 64 there are formed holders or carrier elements 66 holding a heating cable 68. The heating cable 68 is arranged in form of a helix on the inner side of the wall 64. In an alternative embodiment the heating cable 68 may be arranged on the outer side of the wall 64. Furthermore, it would be possible to arrange heating cables on both sides of the wall 64 or to integrate an electric heating element like a heating cable or wire into the wall 64, for example in an injection molding process. Preferably both, the heating cable 68 and the heating wires 40 of the heating pad 38 are connected to a common control, preferably the control electronics 8 of the pump. The heating cable 68 and the heating wires 40 may be connected in series or in parallel to allow a common control of the heating elements. By the additional arrangement of a further heating unit 62 partly surrounding the first coupling part 34 an improved heating of the coupling part, in particular at its lower end can be ensured to prevent icing. Thus, by arrangement of the heating unit 62 in addition to the heating pad 38 icing can be prevented more securely. It has to be understood, that further alternative embodiments are possible, for example it may be possible to just arrange the heating unit 62 without the use of a heating pad 38 as disclosed above.

[0057] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 Bezugszeichenliste

[0058] 2 pump

[0059] 4 magnetic coupling

[0060] 6 drive motor

[0061] 7 output shaft

[0062] 8 control electronics

[0063] 10 electronics housing

[0064] 12 impeller

[0065] 14 pump shaft

[0066] 16 pump housing

[0067] 17 bottom portion of the pump housing

[0068] 18 inlet

[0069] 20 outlet

[0070] 22 upper portion of the pump housing

[0071] 24 wall

[0072] 26 opening

[0073] 28 rotor can

[0074] 30 flange

[0075] 32 fastening ring, menacle ring

[0076] 34 first coupling part, outer coupling part

[0077] 36 second coupling part, inner coupling part

[0078] 38 heating pad

[0079] 40 heating wires

[0080] 42 power cable

[0081] 44 temperature sensor

[0082] 46 gap

[0083] 48 retaining element

[0084] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025 50 clip

[0085] 52 yokes

[0086] 54 lug

[0087] 56 fastening holes

[0088] 58 fastening bolts

[0089] 60 cable

[0090] 62 heating unit

[0091] 64 wall

[0092] 66 holders

[0093] 68 heating cable x rotational axis

[0094] Patentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025

Claims

Claims1. Coolant pump for feeding a coolant, the pump (2) comprising at least one impeller ( 12) and an electric drive motor (6) driving this at least one impeller (12), characterized by a magnetic coupling (4) between the drive motor (6) and the impeller (12) with at least one first rotatable coupling part connected to a rotor of the drive motor (6), at least one second coupling part (36) connected to the impeller (12) and with a separating wall (24) between the first coupling part (34) and the second coupling part (36), wherein the separating wall (24) hermetically seals a coolant space with the impeller (12) and the second coupling part (36) therein, and by at least one heating device arranged to heat at least a portion of the coolant pump to prevent icing.

2. Coolant pump according to claim 1 , characterized in that the electric drive motor (6) comprises a speed control and preferably a frequency converter for controlling the drive speed of the drive motor (6).

3. Coolant pump according to claim 1 or 2, characterized in that the at least one heating device (38) is located and configured to heat the first coupling part (34) and / or the surroundings of the first coupling part (34) and / or to heat at least one portion of the separating wall (24), at least one element connected to the separating wall (24)and / or at least a part of a pump housing (16).

4. Coolant pump according to one of the preceding claims, characterized in that at least one element or wall (24) portion heated by the heating device (38) is facing the first coupling part (34). atentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 20255. Coolant pump according to one of the preceding claims, characterized in that a rotational axis (x) of the first coupling part (34) and a rotational axis (x) of the second coupling part (36) are aligned with one another and that preferably the first coupling part (34) is arranged concentrically to the second coupling part (36).

6. Coolant pump according to one of the preceding claims, characterized in that said separating wall (24) is a rotor can (28) surrounding the second coupling part (36), wherein the first coupling part (34) is arranged in the outer circumference of said can (28).

7. Coolant pump according to one of the preceding claims, characterized in that the separating wall (24), preferably in form of a rotor can (28), is held on a pump housing (16) by a fastening ring (32) overlapping a flange (30) of the separating wall (24), wherein preferably the heating device is in contact with this fastening ring (32).

8. Coolant pump according to one of the preceding claims, characterized in that the heating device (38) is an electric heating device and preferably comprises a temperature control.

9. Coolant pump according to one of the preceding claims, characterized in that the heating device (38) comprises at least one temperature sensor (44) which preferably is arranged to detect a temperature of the heating device in a region adjacent to the first coupling part (34).

10. Coolant pump according to one of the preceding claims, characterized in that the heating device is connected to control electronics (8) of the drive motor (6) and that a temperature control of the heating device (38) is performed by the control electronics (8) of the drive motor (6). atentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 20251 1 . Coolant pump according to one of the preceding claims, characterized in that the heating device (38) comprises at least one heating unit (38) made from a plastic material and having heating elements (40) embedded into the plastic material.

12. Coolant pump according to one of the preceding claims, characterized in that the heating device comprises at least one heating unit (38) attached to the separating wall (24) and / or a heat conducting element connected to said separating wall (24).

13. Coolant pump according to one of the preceding claims, characterized in that the heating device comprises at least one heating unit (62) at least partly surrounding said separating wall (24) and the first rotatable coupling part (34).

14. Coolant pump according to claim 13, characterized in that the heating unit (62) at least partly surrounding said separating wall (24) and the first rotatable coupling part (34) comprises at least one heating element (68).

15. Coolant pump according to one of the preceding claims, characterized in that the heating device comprises a heating unit in form of a heating pad (38) which is attached to a surface of a fastening ring (32) of the rotor can (28).

16. Coolant pump according to one of the preceding claims, characterized in that the heating pad (38) on its surface facing away from the fastening ring (32) is at least partly covered by a retaining element (48) and wherein this retaining element (48) preferably is secured to the fastening ring (32) by screws (58) clamping the fastening ring (32) on a pump housing (16). atentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 202517. Coolant pump according to claim 15 or 16, characterized in that said heating pad (38) is thermally connected to a heat-transmitting element or a heating unit (62) at least partly surrounding said separating wall (24) and the first rotatable coupling part (34).

18. Coolant pump according to claim 17, characterized in that said heating pad (38) and the heating unit (62) at least partly surrounding said separating wall (24) and the first rotatable coupling part (34) each comprise heating elements (40, 68) which, preferably, are electrically connected.

19. Use of a coolant pump according to one of the preceding claims in a cooling application, characterized in that the coolant pump is pumping a coolant at a temperature below 0°C and preferably below -10°C, wherein the coolant preferably is ammonia. atentanwdlte Hemmer Lindfeld Frese GP 3844 WO, 16 / 12 / 2025

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