EP4001654A1 - Self-ventilating wet rotor pump - Google Patents

Abstract

The invention relates to a glandless pump (1) for conveying a liquid, having a rotor space (14) filled with the liquid, in which a rotor (3) is arranged so that it can rotate and which is separated from a stator (4) in a liquid-tight manner by a can (5). . A semi-permeable membrane (17a, 17b, 17c) is arranged between the rotor space (14) and the atmosphere outside the glandless pump (1) and is designed to let air through and hold back the liquid. In this way, automatic venting is effected during operation of the glandless pump.

Description

The invention relates to a glandless pump for conveying a liquid, having a rotor space filled with the liquid, in which a rotor is rotatably arranged and which is separated from a stator in a liquid-tight manner by a can.

Wet rotor pumps are well known. They are often used in heating and cooling applications to convey a heat transfer medium, for example water or a water/glycol mixture, in a circuit. Furthermore, glandless pumps are also used in drinking water applications. Because the pumped medium floods the rotor space, the plain bearings used to support the pump shaft are always lubricated and, depending on the temperature of the pumped medium, the stator is also cooled.

Even when the glandless pump is started up, there is air in the rotor space that has to be displaced by the pumped liquid. It is known to allow the air to escape from the rotor space by manual venting using a vent screw. This then fills the rotor chamber with pumped liquid. However, this is only possible if there is a corresponding overpressure in the pump compared to the atmosphere, i.e. the pump is installed in its operating position.

In order to achieve automatic venting and also an improvement in the cooling effect of the medium, glandless pumps are designed in such a way that there is a continuous flow through the rotor space. For this purpose, on the one hand, there is a flow connection to the pump chamber at the axial end of the rotor chamber facing the pump impeller, be it in the form of a groove or a channel or simply due to the necessary plain bearing gap, through which the pumped medium also penetrates into the rotor space. In order to achieve throughflow, the pump shaft is designed as a hollow shaft and is open at both ends, ie on the one hand to the suction mouth of the impeller and on the other hand to the axial end of the rotor space opposite the impeller. As a result of the negative pressure generated at the suction port of the impeller, this causes a pressure difference between the suction side of the pump and the rotor chamber, whereby the liquid in the rotor chamber is sucked in at the end of the pump shaft opposite the impeller or sucked out of the rotor chamber and through the hollow shaft and a fluid therein Filter flows to the suction mouth. Liquid then flows from the pump chamber into the rotor chamber via the aforementioned flow connection. Since the pumped liquid regularly contains air distributed in the smallest bubbles, this air also gets into the rotor space, in which a liquid/air mixture exists due to the rotating rotor. The air is therefore only partially conveyed out of the rotor space via the hollow shaft.

The problem of little or no ventilation is particularly critical for glandless pumps that are mounted and operated with a vertical pump shaft, i.e. where the impeller is arranged below the electric motor that drives the pump shaft. Because in this case, the air increasingly collects at the upper axial end, since it is not sucked off. The result is that the upper plain bearing, known in technical jargon as the B-side plain bearing, is no longer lubricated, meaning that the glandless pump can be damaged.

It is therefore the object of the present invention to provide a glandless pump with improved venting of the rotor space.

This task is solved by the glandless pump with the features of claim 1 . Advantageous developments are specified in the dependent claims and are explained below.

According to the invention, a glandless pump for conveying a liquid is provided with a rotor chamber filled with the liquid, in which a rotor is arranged so that it can rotate and which is separated from a stator in a liquid-tight manner by a can. proposed in which a semi-permeable membrane is arranged between the rotor space and the atmosphere outside of the glandless pump, which is designed to let air through and to hold back the liquid. This means that air that has entered the rotor chamber can automatically and reliably escape from it again at any time. This is due to the overpressure in the rotor space compared to the atmosphere. The semi-permeable membrane is permanently active, so venting takes place at all times and requires no manual operation, such as a vent screw. The integration of the semi-permeable membrane in the glandless pump is comparatively easy to achieve in terms of design and has economic advantages, since it means that a hollow shaft can be dispensed with as the pump shaft and the comparatively expensive filter inside the hollow shaft is therefore also eliminated.

The membrane is preferably arranged at an axial end of the rotor space. This is structurally advantageous because the hermetic separation between rotor and stator, in particular the can, is not impaired by the ventilation. No other functionality of other components is impaired either, such as storage, lubrication, or circulation in the rotor space, etc. The arrangement of the membrane at an axial end of the rotor space is also advantageous with regard to statics, because the openings required for venting do not transmit any force enforce components.

It is of particular advantage if the membrane is arranged at that axial end of the rotor chamber which is opposite the pump impeller, i.e. at the so-called B-side of the glandless pump. This ensures that the ventilation according to the invention also works reliably in glandless pumps with a vertical pump shaft, i.e. in glandless pumps that are arranged and operated during normal operation in such a way that their pump shaft is vertical, i.e. the impeller is below the electric motor. A further advantage of this B-side arrangement of the membrane is that the distance between the rotor space and the atmosphere is small, in particular minimal.

Various options for integrating the semi-permeable membrane into the glandless pump are presented below.

The rotor space is closed at the axial end by a sealing body. In a first embodiment, the closure body is in one piece with the can and closes it at the named axial end, so that the can is a containment shell and the closure body is its bottom. This embodiment variant is advantageous if the can and the closure body can be made from the same material. The split tube and closure body then form one part and are produced in a common manufacturing step. A protruding bearing mount can be formed on the inside of the closure body or containment pot base in order to accommodate a sliding bearing for supporting the pump shaft. The split tube and closure body can be made of plastic, for example. Alternatively, the bottom can have a pot-like depression in which a plain bearing or a plain bearing mount lies. In this embodiment, the can and the closure body can be made of metal, for example, by deep-drawing a metal sheet.

In a second embodiment, the closure body can be independent of the can, i.e. it can form a separate part. Thus, different materials can be used for the can on the one hand and the closure body on the other hand. For example, the closure body can be made of brass and the can made of a plastic, in particular a wound carbon fiber reinforced plastic (CFRP). The closure body can be a bearing carrier for accommodating a plain bearing supporting the pump shaft.

In the first as well as in the second embodiment variant, a central opening can be formed in the closure body, preferably coaxially to the pump shaft. The opening is therefore located axially behind the pump shaft between the plain bearing and the rotor chamber wall, where air always collects, especially when the pump shaft is vertical. In a glandless pump arrangement with a vertical pump shaft, this is also the highest point. Liquid air can escape from the rotor space through the opening.

In both of the aforementioned design variants, the semipermeable membrane can be arranged differently in or on the closure body. This is also closed take into account that the membrane can in principle have any shape. The membrane is preferably designed in the form of a disk, in particular a circular disk. Alternatively, it can have the shape of a ring, in particular a hollow cylinder section with a preferably circular cross section.

For example, a disk-shaped, semi-permeable membrane can rest against the closure body inside the rotor chamber and cover the opening. The concern can be direct or indirect, for example via a sealing ring. A fixing element, e.g. ring-shaped, inserted inside the closure body can press the membrane against the opening.

In a preferred embodiment, the semi-permeable membrane lies against the closure body outside of the rotor chamber and either covers or surrounds the opening. It makes sense to use a disk-shaped membrane for covering and an annular membrane for surrounding. The arrangement outside of the rotor space simplifies access to the diaphragm, since the wet-running assembly of the pump does not have to be dismantled to replace the diaphragm. This concern can also be direct or indirect here, for example via a sealing ring.

The closure body preferably has a receptacle which surrounds the opening in a ring-shaped manner and in which the membrane lies in a form-fitting manner. The mount holds the membrane in position in the radial direction. In the axial direction, depending on the axial height, the membrane can lie entirely in the receptacle or protrude axially from the receptacle. The receptacle is preferably formed by a radial recess viewed from the perspective of the rotor space along the opening in the closure body outwards in the axial direction. In other words, the opening on the side of the closure body facing away from the rotor space is larger in the radial direction, in particular provided with a larger diameter, than on the side facing the rotor space. The recess or transition from one diameter to the other is suitably stepped, so that a sealing seat is created in the form of an annular inner corner. So provides the recording in particular in connection with a seal between the membrane and the Closure body can be arranged in the receptacle or in said sealing seat, for a good sealing effect.

According to a further embodiment variant, the rotor chamber can be closed at the axial end by a closure body, which itself forms the semi-permeable membrane. In this variant embodiment, the closure body can also be a bearing carrier for accommodating a plain bearing supporting the pump shaft. In other words, this bearing support, which closes the can, is the diaphragm. Since the closure body is in contact with the liquid and the air in the rotor space, no opening is required in the closure body in this embodiment variant.

The glandless pump has a structurally particularly simple and at the same time robust design if the sealing body rests directly or at least indirectly on an axial end wall of a motor housing of the glanded pump enclosing the stator and a housing opening is formed in the end wall so that air from the rotor chamber can escape to the atmosphere through the housing opening can escape. The housing opening and the opening in the closure body are preferably aligned with one another, in particular arranged coaxially.

In order to simplify the accessibility of the semi-permeable membrane, for example when changing the membrane, it is advantageous if the receptacle in the closure body is on the side facing the motor housing and the dimension(s), in particular the diameter, is the same as the housing opening in the motor housing or larger than the dimension(s), particularly the diameter, of the receptacle. Thus, the membrane can be easily inserted and removed from outside the motor housing in the recording, for example, to replace it in case of maintenance. It should be noted that the opening in the closure body and the housing opening in the end wall of the motor housing do not necessarily have to be round. However, round, in particular circular, openings are easier to produce

In order to ensure tightness, a fixing element can be inserted, in particular screwed, into the housing opening and presses the membrane against the closure element in a sealing manner. The fixing element can consist of a head and a shaft exist, with the head protruding radially beyond the shank. When the fixing element is in place, the head rests on the outside of the motor housing and thus forms a screw-in limitation. However, a headless version is also possible. The fixing element preferably has a maximum diameter in the manner of a screwable blind plug which is 2-5 times greater than its overall axial length.

It is ideal if the membrane is arranged between two sealing rings, so that both tightness to the closure body and tightness to the fixing element is guaranteed.

As already mentioned, in a variant embodiment, the membrane can be a ring, in particular with a rectangular cross-section. This means that the membrane encloses a cylindrical space that is not closed in the axial direction. The cylindrical spatial area can advantageously be closed by the fixing element mentioned, which for this purpose can be designed, for example, as a solid screw.

The cylindrical space area is filled with the liquid in the rotor space as it expands the rotor space. Air from the rotor space can then pass through the membrane in the radial direction. So that the air can also escape to the atmosphere, the receptacle and the housing opening can each have at least one radial extension, for example a groove-like extension, which are aligned with one another in particular in order to form a channel for escaping air, while the fixing element closes the housing opening while leaving the extension free locked. The air can thus flow past the fixing element used.

As also already mentioned, in another embodiment the membrane can be a disk, in particular a circular disk. This means that the membrane closes the opening in the closure body. Air from the rotor space can then pass through the membrane in the axial direction. So that the air can also escape to the atmosphere, the fixing element can have a cavity which opens at one end to the membrane and at the other end to the atmosphere. The air can thus flow through the fixing element used. For example, the fixing element can form a hollow screw.

In the further embodiment variant mentioned above, in which the closure body forms the membrane, the use of a fixing element is not necessary. Rather, the housing opening can extend freely up to the closure body. This can, for example, be held in a form-fitting manner on or in the end wall of the motor housing.

Provision can be made for the fixing element to extend axially into the closure body. In the configuration of the fixing element as a screw, it can be screwed into the closure body or form a positive connection with it in some other way.

As explained above, the closure body can have a receptacle for the membrane and optionally an intermediate sealing ring. Such a receptacle can alternatively or additionally be formed on the fixing element, more precisely on the axial end of the fixing element facing the closure body. The membrane can thus be at least partially accommodated in the fixing element.

In the embodiment variants described above, the membrane is clamped independently of the closure body, the motor housing and the fixing element and between the closure body and the fixing element. However, it is also conceivable to integrate the membrane into the closure body or the fixing element so that it forms a structural unit therewith.

In this sense, in a preferred embodiment, a fixing element can be positively and/or non-positively inserted, in particular screwed, into the housing opening, in which the membrane is integrated, with the fixing element then sealingly closing the central opening of the closure body. Analogously to the previous embodiment, this fixing element can be designed with a hollow space which extends through the entire axial length and is interrupted by a disc-shaped semipermeable membrane. Alternatively, this fixing element can have a cavity which extends over only part of the axial length, so that the fixing element is pot-like with a bottom is formed, wherein an annular semipermeable membrane lies in the cavity and at least one air outlet opening is formed in the wall of the fixing element at its axial height. The fixing element thus forms a structural unit together with the semipermeable membrane, which makes it particularly easy to change the membrane, since the membrane is removed and inserted at the same time as the fixing element.

The semi-permeable membrane can be made of a plastic material commonly used for osmosis applications. the membrane can be produced as a semipermeable film. It can therefore withstand high liquid pressures, but is permeable to gaseous media. The membrane material can be polytetrafluoroethylene (PTFE) or polypropylene (PP), for example.

The glandless pump according to the invention is preferably and intended to be installed and operated in an arrangement in which its pump shaft is vertical. In this respect, the invention also relates to the use of a glandless pump according to the invention with a vertical pump shaft.

Further features, advantages and properties of the invention are explained below using exemplary embodiments and the attached figures. In the figures, reference symbols always denote the same or equivalent components, areas, directional or locational information.

It should be pointed out that, in the context of the present description, the terms “have”, “comprise” or “contain” in no way exclude the presence of further features. Furthermore, the use of the indefinite article with an object does not exclude its plural form.

Fig. 1:

eine Nassläuferpumpe nach dem Stand der Technik;

Fig. 1a:

eine vergrößerte Darstellung einer Modifikation innerhalb des in Fig. 1 eingekreisten Bereichs nach einer ersten Ausführungsvariante der Erfindung, die eine radiale Selbstentlüftung mit einer ringförmigen semipermeablen Membran verwendet;

Fig. 1b:

eine vergrößerte Darstellung einer Modifikation innerhalb des in Fig. 1 eingekreisten Bereichs nach einer zweiten Ausführungsvariante der Erfindung, die eine axiale Selbstentlüftung mit einer scheibenförmigen semipermeablen Membran verwendet;

Fig. 1c:

eine vergrößerte Darstellung einer Modifikation innerhalb des in Fig. 1 eingekreisten Bereichs nach einer dritten Ausführungsvariante der Erfindung, bei der die semipermeable Membran in ein Fixierelement integriert ist.

Fig. 2:

eine vierte Ausführungsvariante, bei der ein Lagerträger die Membran bildet.

Show it:

Figure 1:

a gland pump according to the prior art;

Figure 1a:

an enlarged view of a modification within the in 1 circled area according to a first embodiment of the Invention using radial self-venting with an annular semipermeable membrane;

Figure 1b:

an enlarged view of a modification within the in 1 circled area according to a second embodiment of the invention using axial self-venting with a disc-shaped semipermeable membrane;

Figure 1c:

an enlarged view of a modification within the in 1 circled area according to a third embodiment of the invention, in which the semipermeable membrane is integrated in a fixing element.

Figure 2:

a fourth variant in which a bearing support forms the membrane.

figure 1 shows a glandless pump 1 according to the prior art with a wet-running electric motor, the pump housing being omitted here for reasons of clarity. The glandless pump 1 has a motor housing 2 in which a stator 4 is located, which is hermetically separated by a can 5 from a rotor chamber 14 through which the pumped liquid flows. A permanent-magnetic rotor is arranged in the rotor space 14 and rotates “wet” in the liquid. The rotor 3 is connected in a torque-proof manner to a pump shaft 6 which protrudes from the stator 4 at one end and carries an impeller 8 there. The pump shaft 6 is designed as a hollow shaft with a cavity 7 and is open at both ends. It is rotatably supported by a slide bearing 10 both at the impeller end, ie the so-called A-side, and at the end opposite this, ie the so-called B-side. On the non-drive end, the plain bearing 10 is accommodated in a bearing carrier 9 which seals the axial end of the can 5 opposite the impeller 8 by means of an O-ring 27 . In this respect, the bearing support 9 forms a closure body. The can 5 is formed here in two layers from an inner and an outer tube.

The bearing support 9 is accommodated in the motor housing 2 in a form-fitting manner, more precisely cast there. Its shape is essentially pot-shaped with a cylindrical ring, within which the slide bearing 10 is held, and a rear wall 22. The rear wall 22 lies against an end wall 13 of the motor housing 2 at. The bearing bracket 9 is made of brass, whereas the motor housing is made of die-cast aluminum, which is why the liquid must not reach the motor housing 2 for reasons of corrosion. The bearing carrier 9 has longitudinal grooves 11 which are open radially inwards, are distributed circumferentially and extend axially and which connect the central rotor space 14 with a space area 12 axially between the plain bearing 10 and the rear wall 22 .

During operation of the glandless pump 1, the impeller 8 generates a negative pressure at its suction mouth, as a result of which liquid is sucked from the spatial area 12 through the cavity 7 to the suction mouth. The liquid passes through a filter 26 which is introduced into the cavity 7 at the impeller-side end of the hollow shaft 6 . Thus, there is also a negative pressure in the space 12 , which is why liquid flows from the central rotor space 14 through the grooves 11 into the space 12 . At the same time, liquid flows from the pump chamber via the bearing gap of the plain bearing on the impeller side into the rotor space 14 so that the liquid circulates through the rotor space 14 as a whole. This lubricates the bearings 10, cools the stator 4 and conveys air introduced into the rotor space 14 out of it again. However, this concept is problematic with regard to the air with a vertical pump shaft 6, i.e. when the arrangement of the glandless pump 1 is such that the shaft is vertical and the impeller 8 is below the electric motor 3, 4. The air would then collect in the space 12 and not be sucked out.

In order to overcome this disadvantage, the bearing bracket 9 is modified according to the invention in that a semipermeable membrane 17a, 17b, 17c is arranged between the rotor space 14 and the atmosphere outside the glandless pump 1 and is designed to let air through and hold back the liquid.

Fig. 1a shows a section of a first embodiment of such a glandless pump 1 with a semi-permeable membrane 17a, the section showing the area surrounding the B-side bearing bracket 9. The membrane 17a is therefore arranged at that axial end of the rotor chamber 14 which is opposite the pump impeller 8. Thus, neither the hermetic separation between the rotor 3 and the stator 4, and consequently the can 4, nor the functionality of another component is impaired by the venting of the rotor chamber 14 by means of the membrane 17a.

The arrangement of the membrane 17a at an axial end of the rotor chamber 14 also has the advantage that the openings required for venting do not pass through any force-transmitting components. In addition, the glandless pump 1 can be installed for the intended operation in such a way that the impeller 8 is below the electric motor 3, 4, i.e. the pump shaft 6 is vertical, because in this case the semi-permeable membrane 17a is at the highest point of the rotor chamber 14. Any air will rise there, can then diffuse through the membrane 17a and escape the short way to the atmosphere.

In the rear wall 22 of the bearing bracket 9 there is an opening 24 which is coaxial to the pump shaft 6 . Furthermore, a housing opening 23 is formed in the end wall 13 of the motor housing 2 . The two openings 23, 24 are aligned and provide the seat for the semi-permeable membrane 17a. For this purpose, the bearing support 9 has a receptacle 25 which annularly surrounds the opening 24 on the side facing the end wall 13 and in which the membrane 17a lies in a form-fitting manner. Viewed from the rotor chamber 14 in the axial direction, the receptacle 25 is formed by a radial recess such that the opening 24 on the side of the bearing bracket 9 facing away from the rotor chamber 14 has a larger diameter in the radial direction than on the side facing the rotor chamber 14 side and the transition from the smaller to the larger diameter is stepped. A projection 21 thus remains on the side of the opening 24 facing the rotor space 14, which in turn provides a sealing seat in the form of an annular inner corner on its side facing away from the rotor space 14.

A sealing ring 18, 19 with a rectangular cross section is applied to both axial end faces of the membrane 17a, a first sealing ring 18 of these sealing rings 18, 19 being arranged in the sealing seat formed by the projection 21 and the receptacle 25. The membrane 17a also has the shape of a ring with a rectangular cross section. Viewed in its entirety, the membrane 17a is a hollow cylinder section with a circular cross section. The membrane 17a thus encloses a central cavity 16a which is open towards the rotor space 14 . Air can thus escape from this central cavity 16a by radial permeation through membrane 17a, see arrow A. Since the sum of the axial widths of the first sealing ring 18 and the membrane 17a is greater than the axial width of the recess, the membrane 17a projects somewhat in this embodiment variant from the rear wall 22 of the bearing carrier 9 and extends into the housing opening 23 . A second sealing ring 19 rests on the face of the membrane 17a facing away from the rotor space 14 .

A fixing element 20a is inserted, more precisely screwed, into the housing opening 23 of the end wall 13 of the motor housing 2 . The housing opening 23 provides an internal thread for this purpose, with the fixing element 20a having an external thread. The fixing element 20a is essentially in the form of a blind plug, i.e. it has an overall axial length which is considerably less, in particular only about 1/4 of the maximum diameter. The fixing element 20a consists of a head and a shank, the maximum diameter being at the head, with which the fixing element 20a is supported on the outside of the motor housing 2 and thus forms a screw-in limitation.

The fixing element 20a is solid. The periphery of its end face facing the rotor chamber 14 bears against the second sealing ring 19 and presses it against the membrane 17a, which in turn presses against the first sealing ring 18 and the latter against the projection 21 . Thus, the tightness of the openings 23, 24 is guaranteed. The sealing ring 19 can also be a sealing disk here.

So that the air can also escape to the atmosphere, the receptacle 25 and the housing opening 23 each have at least one radial extension in the form of a groove 15a, 15b, the groove 15a of the receptacle 25 being aligned with the groove 15b of the housing opening, around a channel for escaping air, while the fixing element 20a closes the housing opening 23, leaving the groove 15b free. The air can thus flow through the inserted fixing element 20a along the in 1 shown arrow A flow past.

Overall, the inventive arrangement of a semipermeable membrane 17a creates a structurally simple realization of an automatic venting of the rotor space 14 . The membrane 17a is easily accessible for maintenance purposes through the housing opening 23 in the end wall 13 of the motor housing 2 and can be changed easily, since only the fixing element 20a has to be loosened for this purpose.

It should be noted that pump electronics, not shown, can be attached to the axial end wall 13 of the motor housing 2, in particular screw-fastened. However, this is not in gas-tight contact with the end wall 13, but is at a distance from it, forming a gap, so that this gap also forms the atmosphere outside of the glandless pump 1. The fixing element can be made of metal or plastic.

Fig. 1b shows a second embodiment variant of the invention, with an enlarged representation of a modification within the scope shown in FIG 1 circled area is shown. This second embodiment variant differs from the first variant essentially in that it uses axial self-venting with a disc-shaped semipermeable membrane 17b. The membrane 17b here has the shape of a circular disc which rests on the projection 2 via the first sealing ring 18 and closes the opening 24 in the bearing carrier 9 . The fixing element 20b is not solid here, but hollow-cylindrical with a cavity 16b open on both sides, so that the air diffusing axially through the membrane 17b can also escape axially through the fixing element 20b, as the arrows B indicate. The grooves 15a, 15b can thus be dispensed with. Otherwise, the second embodiment variant is identical to the first embodiment variant, so that reference can be made to the above statements.

1c shows a third embodiment variant of the invention, with an enlarged representation of a modification within the scope shown in FIG 1 circled area is shown. This third embodiment variant differs from the first and second variants essentially in that the semipermeable membrane 17b is integrated into the fixing element 20b and thus forms a structural unit with it, which can be inserted into the housing opening 23 and easily replaced. The membrane 17b again has the shape of a disk, in particular a circular disk. The fixing element 20b can be made of plastic here and the membrane 17b can be embedded in this plastic by injection molding. In this embodiment, only one sealing ring 18 is required, which the fixing element 20b against the Closure element or the bearing bracket 9 presses. This sealing ring 18 surrounds the opening 24 in the rear wall 22 of the bearing carrier 9 on the outside, so that the opening 23 does not have to have a receptacle 25, ie no recess or no change in diameter along its axial length. Otherwise, the third embodiment variant is identical to the first or second embodiment variant, so that reference can be made to the above statements.

2 shows a fourth embodiment of the invention analogous to figure 1 . In this embodiment variant, the closure body or the bearing support 9 itself is a semipermeable membrane 17c. An additional opening in the rear wall 22 of the bearing support 9 and seals, receptacles, channels and the fixing element can thus be dispensed with. The rear wall 22 of the bearing support 9 rests against the inside of the end wall 3 of the motor housing 2, which is directed towards the rotor chamber 14 and in which only the housing opening 23 is formed. This is here coaxial to the motor axis 28, but this is not absolutely necessary. Air can thus diffuse out of the space 12 through the bearing support 9 and escape through the housing opening 23 to the atmosphere.

It should be understood that the foregoing description is given by way of example for purposes of illustration and does not limit the scope of the invention in any way. Features of the invention that are indicated as "may", "exemplary", "preferred", "optional", "ideal", "advantageous", "optional" or "suitable" are to be considered purely optional and also limit the does not include a scope of protection, which is defined solely by the claims. Insofar as elements, components, process steps, values or information are mentioned in the above description which have known, obvious or foreseeable equivalents, these equivalents are also included in the invention. The invention also includes any changes, alterations or modifications of exemplary embodiments which have the exchange, addition, alteration or omission of elements, components, method steps, values or information as their subject matter, as long as the basic idea according to the invention is retained, regardless of whether the change, alteration, or modifications improves or degrades an embodiment.

Although the above description of the invention mentions a large number of physical, non-physical or procedural features in relation to one or more specific exemplary embodiments, these features can also be used in isolation from the specific exemplary embodiment, at least insofar as they do not necessarily require the presence of further features. Conversely, these features mentioned in relation to one or more specific exemplary embodiment(s) can be combined with one another as desired and with other disclosed or undisclosed features of exemplary embodiments shown or not shown, at least insofar as the features are not mutually exclusive or lead to technical incompatibilities.

Reference List

1

glandless pump

2

motor housing

3

rotor

4

stator

5

cracking tube

6

Wave

7

cavity

8th

Wheel

9

closure body, bearing carrier

10

bearings

11

groove

12

space area

13

bulkhead

14

rotor space

15a

Groove in bearing housing

15b

Groove in motor housing

16a

central room

16b

cavity

17a

annular membrane

17b

disc-shaped membrane

17c

Closure body as a membrane

18

first sealing ring

19

second sealing ring

20a

Fixing element, massive screw

20b

Fixing element, hollow screw

21

head Start

22

back panel

23

case opening

24

opening

25

Recording, radial return

26

filter

27

O ring

28

motor axis

Claims (14)

Wet-running pump (1) for pumping a liquid, with a rotor space (14) filled with the liquid, in which a rotor (3) is rotatably arranged and which is separated in a liquid-tight manner from a stator (4) by a can (5), characterized in that in that a semipermeable membrane (17a, 17b, 17c) is arranged between the rotor space (14) and the atmosphere outside the glandless pump (1) and is designed to let air through and to hold back the liquid. Wet-running pump according to Claim 1, characterized in that the membrane (17a, 17b, 17c) is arranged at an axial end of the rotor chamber (14), in particular that axial end which is opposite the pump impeller (8). Wet-running pump according to Claim 2, characterized in that the rotor chamber (14) is closed at the axial end by a closure body (9) in which a coaxial opening (24) is formed. Wet-running pump according to Claim 3, characterized in that the closure body (9) has a receptacle (25) which surrounds the opening (24) and in which the diaphragm (17a, 17b) lies in a form-fitting manner. Wet-running pump according to Claim 2, characterized in that the rotor space (14) is closed at the axial end by a closure body (9) which forms the membrane (17c). Wet-running pump according to one of Claims 2 to 5, characterized in that the closure body (9) is a bearing carrier for receiving (25) a plain bearing (10) supporting the pump shaft (6). Wet-running pump according to one of Claims 3 to 6, characterized in that the closure body (9) rests directly or indirectly on an axial end wall (13) of the motor housing (2), in which a housing opening (23) is formed so that air can escape from the rotor space (14) can escape. Wet-running pump at least according to Claims 4 and 7, characterized in that the receptacle (25) is on the side facing the motor housing (2) and the dimension(s), in particular the diameter of the housing opening (23), is equal to or larger than the dimension ( en), in particular the diameter of the receptacle (25). Wet-running pump according to Claim 7 or 8, characterized in that a fixing element (20a, 20b) is inserted, in particular screwed, into the housing opening (23) and presses the membrane (17a, 17b) sealingly against the closure body (9). Wet-running pump according to one of the preceding claims, characterized in that the membrane (17a, 17b) is arranged between two sealing rings (18, 19). Wet-running pump at least according to Claim 9, characterized in that the membrane (17a, 17b) is a ring, and that the receptacle (25) and the housing opening (23) each have at least one radial extension (15a, 15b) which are aligned with one another to form a channel for escaping air, while the fixing element (20a, 20b) closes the housing opening leaving the extension (15a, 15b) closed. Wet-running pump at least according to Claim 9, characterized in that the membrane (17a, 17b) is a disc and the fixing element (20b) has a cavity (16b) which opens at one end to the membrane and at the other end to the atmosphere. Wet-running pump at least according to Claims 2 and 7, characterized in that a fixing element (20a, 20b) is inserted, in particular screwed, into the housing opening (23), in which the membrane (17a, 17b) is at least partially accommodated or integrated, the fixing element (20a, 20b) sealingly closes the central opening (24) of the closure body (9). Wet-running pump at least according to one of the preceding claims, characterized in that it is intended to be operated in an arrangement in which its pump shaft (6) is vertical.

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