EP2660473B1 - Waste water pump - Google Patents

Description

The invention relates to a dirty water pump with the features specified in the preamble of claim 1.

Dirty water pumps, which may be designed in particular as submersible pumps, are used for pumping out sewage or wastewater, such wastewaters being frequently mixed with solids. These pumps are usually equipped with a single-channel or a multi-channel impeller for conveying the waste water. Such pumps are for example off EP 1 300 594 B1 and WO 2011/079892 known.

The solids contained in the effluents can lead to a blockage of the impeller. In particular, it is problematic that these solids can accumulate in a Radseitenraum on the outside of the impeller and then can lead to a blockage of the impeller.

Out GB 2 310 252 a pump is known in which in the sealing gap at the suction mouth of the impeller, a thread is formed, through which impurities are to be moved out of the gap. However, even with this embodiment, a setting of impurities in the Radseitenraum can not be reliably prevented, because there is an excessive pressure difference between the pressure side and suction side.

DE 199 60 160 A1 discloses a pump with an impeller having a suction mouth with a surrounding radially directed sealing surface. This sealing surface is applied to a stationary seal, wherein the seal is supported on a radially surrounding webs on a surrounding housing.

It is an object of the invention to provide an improved sump pump, wherein the risk of blocking of the impeller by impurities is further reduced.

This object is achieved by a dirty water pump with the features specified in claim 1. Preferred embodiments will become apparent from the subclaims, the following description and the accompanying figures.

The dirty water pump according to the invention has at least one impeller, preferably only one impeller. The impeller is driven in rotation in a known manner via a drive motor. In this case, the drive motor, preferably an electric motor, be integrated with the dirty water pump to a pump unit, in particular in the form of a submersible pump unit. The impeller has a central suction mouth, through which the water to be pumped is sucked. The dirty water pump according to the invention is not necessarily limited to the conveyance of water in the true sense. The dirty water pump according to the invention could also be used to promote other liquids use.

The suction mouth is surrounded by an annular sealing surface. In this case, the sealing surface is preferably substantially cylindrical or conical. The sealing surface seals against a stationary seal held in a surrounding pump housing or volute.

According to the invention, at least one groove is formed in the sealing surface, which groove extends beyond the abutment region of the seal on the sealing surface. In this case, the groove preferably extends with its two opposite longitudinal ends beyond the contact region of the seal. The groove communicates with a first end, ie longitudinal end, with the Radseitenraum and with a second opposite end or longitudinal end with the suction side of the impeller in combination. The Radseitenraum is the area inside the pump or Spirolgehäuses, which surrounds the impeller in the region of the side of the seal or sealing surface facing away from the suction mouth. The Radseitenraum thus lies between the suction side and the pressure side of the impeller in its peripheral region and thus forms an intermediate pressure chamber, in which usually a lower pressure than in the pressure chamber of the spiral housing, ie in the outlet region of the impeller, and a higher pressure than on the suction side of the impeller prevails , In this room there is a particular danger that solids or impurities can accumulate and then lead to a blockage of the impeller. Due to the at least one groove, which connects this Radseitenraum with the suction side of the impeller through the sealing gap between the sealing surface and seal, it is possible that such solids or impurities through the groove are fed back to the suction side of the impeller and so from the Radseitenraum be removed.

It is preferred that in the sealing surface one or more grooves formed in the same way are present. The grooves are formed independently of each other, d. H. they do not communicate with each other and each groove has an end which is open to the Radseitenraum and an opposite end, which is open to the suction side of the impeller out. For example, two such grooves may be formed in the sealing surface. The sealing surface may be formed on the impeller itself or formed on a component connected to the impeller. Thus, the sealing surface may for example be located on a wear ring, which is connected to the impeller, in particular interchangeable with the impeller is connected.

Moreover, according to the invention, means for generating turbulence are arranged in the wheel side space adjoining the seal. These means for generating turbulence cause the liquid or the water is kept in the Radseitenraum with the impurities or solids contained in motion, that is swirled. This ensures that the solids or impurities do not accumulate or agglomerate, but rather individually or in small quantities can enter together with the liquid in the grooves described, fed back to the suction side of the impeller by the pressure difference between Radseitenraum and suction side become. The means for generating turbulence thus improve the removal of solids from the Radseitenraum and prevent their accumulation or accumulation, which would no longer allow a discharge or passage through the grooves described. This is important because the grooves, in order not to unduly affect the sealing property between the seal and the sealing surface, can not be made arbitrarily large. Preferably, the grooves have a width between 1 and 8 mm, preferably between 2 and 5 mm, and a depth between 0.5 and 3 mm, more preferably between 1 and 2 mm.

For generating the turbulence in the Radseitenraum various means can be used. In particular, projections and / or depressions may be formed in the walls of the pump housing adjoining the wheel side space. Alternatively or additionally, projections and / or recesses could also be present in the outer surface of the impeller adjoining the wheel side space.

The means for generating turbulence are particularly preferably formed on the seal. This allows a particularly favorable production, since no additional components are required, but only the seal must be designed accordingly and with insertion of the seal in a surrounding pump or volute Also equal to the means for generating turbulence in the Radseitenraum be introduced.

The means for generating turbulence formed on the seal can also be formed as projections and / or depressions. The means for generating the turbulence may be formed exclusively on the seal. Alternatively, it is also possible for such turbulence-generating means to cooperate with further means for generating turbulence on a wall of the pump housing or the impeller facing the wheel side space.

Particularly preferably, the seal is provided on a side facing the Radseitenraum with a structured or wavy surface. Due to the structure or waveform of the surface turbulence is generated in the Radseitenraum. The structure may be formed, for example, in the form of elevations or depressions on the surface of the seal. The Radseitenraum is bounded on one side by the outside of the impeller. As a result of the rotation of the impeller, a movement in the circumferential direction is likewise produced in the liquid in the wheel side space. As the liquid now overflows the structured or undulating surface of the seal, turbulence is created in the wheel side space, which results in a swirling or dispersion of solids and contaminants and prevents accumulation of these solids and contaminants. The structure on the surface of the gasket may be a uniform or unevenly distributed around the circumference shaping or waveform to produce the desired turbulence. The height of the waves, ie the distance between wave trough and wave peak, is chosen so that the desired turbulence and turbulence are achieved. The height of these waves can be between 0 and 10 mm. Preference is given to several peaks, for example eight peaks, over the circumference arranged distributed. However, other numbers of waves are conceivable. The waveform preferably has rounded edges as a whole, but generally includes an angular waveform as well.

According to a further preferred embodiment, the waves have their maximum height on the inner circumference of the seal and flat to the outer periphery out, d. H. the wave crests and / or the wave troughs extend inclined towards the outer circumference, for example at an angle between 6 and 12 °, more preferably between 8 and 10 ° to a cross-sectional plane which extends normal to the axis of rotation of the impeller.

The sealing gap between the seal and the sealing surface is preferably less than 1 mm, more preferably less than 0.75 mm. The seal is preferably made of an elastomer, for example nitrile rubber. In such a material, the wavy surface can be formed very easily. The entire seal can be manufactured with the structured or wavy surface, for example by injection molding. Thus, the wavy surface can be formed very easily.

The sealing surface is preferably formed on an outer circumferential surface of the impeller or of the suction mouth of the impeller and is surrounded on the outside by the seal. The sealing gap between the seal and the sealing surface is thus preferably substantially cylindrical, optionally conical, and extends transversely to a cross-sectional plane which intersects the axis of rotation at right angles. The sealing surface and the seal are thus preferably radially opposite each other, wherein the sealing surface is located radially inwardly and the seal is located radially outward. Ie. the sealing surface is the Facing away from the axis of rotation, while the surface of the seal, which bears against the sealing surface, facing the axis of rotation.

The at least one groove in the sealing surface expediently extends in the direction of rotation of the impeller. Ie. the groove extends inclined to a cross-sectional plane, the cross-sectional plane extending normal to the axis of rotation of the impeller. At the same time, the groove is inclined so that it does not extend parallel to the axis of rotation. Particularly preferably, the groove is inclined at an angle between 5 and 20 °, preferably between 6 and 10 ° with respect to said cross-sectional plane. In this case, the groove preferably extends such that the front end in the circumferential direction of the groove faces the Radseitenraum. Because of this inclination of the groove and the pressure difference between Radseitenraum and suction side of the impeller impurities or solids move from the Radseitenraum through the groove to the suction side of the impeller and back into the suction of the impeller.

Particularly preferably, the groove does not extend completely around the impeller, but only in a peripheral portion of the sealing surface. In this way, a relatively short distance from the Radseitenraum to the suction side of the impeller through the groove is created, which promotes the transport of solids to the suction side of the impeller out. In addition, the groove can be made larger.

In accordance with a further preferred embodiment of the invention, means for dividing solids, in particular fibers, are also provided. These are preferably arranged or formed in an annular gap, which connects the wheel side space with a spiral or pressure space surrounding the wheel. This ensures that solids or fibers, before they enter from the pressure or spiral space in the Radseitenraum, are first crushed. These minced solids are then removed by the means for generating kept in turbulence in the Radseitenraum in motion, so that accumulation or clumping of these solids in parts of Radseitenraumes is prevented and the solids can be conveyed with liquid through the grooves in the sealing surface through back to the suction side of the impeller.

The annular gap preferably forms the lower annular gap of the impeller, which the pressure space of the impeller towards the bottom, d. H. seals to the suction mouth and the Radseitenraum. This annular gap can be designed as a labyrinth seal or part of a labyrinth seal or act.

The annular gap is preferably formed between an outer annular surface on the circumference or outer circumference of the impeller and a radially opposite inner peripheral surface of a pump or volute casing surrounding the impeller.

The means for dividing solids is further preferably formed by at least one in the annular surface radially inwardly directed recess. Ie. the outer ring surface on the impeller has at least one recess, which is directed radially inward and is open towards the outer periphery. Ie. in the annular surface a recess is formed. The recess is preferably shaped so that it has a constant cross-section over its axial extent in the direction of the longitudinal or rotational axis. The shape of the groove is preferably substantially cylindrical, preferably in the form of a half-circular cylinder, d. H. formed with a semicircular cross-section.

More preferably, a plurality of radially inwardly directed recesses are formed in the annular surface, which are preferably distributed uniformly over the circumference. The recesses are in the process formed previously described manner. For example, four such recesses may be evenly distributed over the circumference.

In addition, a radially outwardly directed recess is preferably formed in the inner peripheral surface of the spiral or pump housing opposite the annular surface. Ie. in this inner peripheral surface, a recess is formed, which is open to the inner periphery. This recess, too, preferably has a constant cross-section over its axial extent parallel to the axis of rotation. Thus, the recess is also preferably cylindrical, in particular in the form of a half-circular cylinder formed with a semicircular cross-section. In the inner peripheral surface, preferably only such a groove is formed. This groove is preferably located in a region of the spiral housing, in which the pressure difference between the pressure chamber on the outlet side of the impeller and the Radseitenraum is minimized. The recess is therefore preferably located in the inner peripheral surface in the region of that circumferential end of the spiral space, which faces away from an outlet. This is the area in which there is the least pressure in the spiral space, and thus the lowest pressure difference between the spiral space, which surrounds the outside of the impeller outer circumference, and the Radseitenraum. In this way it is prevented that additional impurities are pressed by a high pressure difference in the Radseitenraum through this groove.

By having the grooves in the inner peripheral surface and the annular surface in opposing surfaces, as the impeller rotates, these grooves pass inside the inner circumferential surface and create a shearing action which results in the separation of solids entering the annular gap.

Fig. 1

eine teilweise geschnittene Gesamtansicht einer erfindungsgemäßen Schmutzwasserpumpe in Form eines Tauchpumpenaggregates,

Fig. 2

eine Schnittansicht des Pumpengehäuses mit darin angeordnetem Laufrad,

Fig. 3

eine Seitenansicht des Laufrades und der Dichtung,

Fig. 4

eine perspektivische Ansicht des Laufrades mit der Dichtung,

Fig. 5

eine Explosionsansicht des Laufrades mit der Dichtung,

Fig. 6

einen Querschnitt durch das Pumpengehäuse mit eingesetztem Laufrad,

Fig. 7

eine perspektivische Ansicht der Dichtung und

Fig. 8

eine Schnittansicht der Dichtung.

The invention will now be described by way of example with reference to the accompanying drawings. In these shows:

Fig. 1

a partially sectioned overall view of a sump pump according to the invention in the form of a submersible pump unit,

Fig. 2

a sectional view of the pump housing with disposed therein impeller,

Fig. 3

a side view of the impeller and the seal,

Fig. 4

a perspective view of the impeller with the seal,

Fig. 5

an exploded view of the impeller with the seal,

Fig. 6

a cross section through the pump housing with inserted impeller,

Fig. 7

a perspective view of the seal and

Fig. 8

a sectional view of the seal.

The dirty water pump shown is designed as a submersible pump unit with an electric drive motor 2 and arranged at the lower end of the drive motor 2 pump housing 4. The pump housing 4 is provided on its underside with a central opening 6, which forms the inlet opening and the suction mouth of the pump unit. In the lateral direction, radially to the axis of rotation X, extends a discharge nozzle 8, to which an outlet line is connected. Inside the pump housing designed as a spiral housing 4, an impeller 10 is arranged, which is designed as a single-channel impeller. The impeller 10 has a suction port 12 on its underside. The suction mouth 12 is surrounded by a concentric with the axis of rotation X extending sealing surface 14, which is formed on the outer circumference of a wear ring 16. The wear ring 16 is placed on the cast wheel 10 at the axial end and can be replaced when worn. Radially opposite, the wear ring 16 concentrically surrounding, in the pump housing 4, the opening 6 surrounding a seal in the form of a sealing ring 18 is arranged. The sealing ring 18 bears with an inner circumference 19 in the form of a sealing lip on the sealing surface 14 sealingly. The sealing ring 18 is made of an elastomeric material and has a metal core for dimensional stability. The sealing ring 18 is exchangeable. He seals over the system on the sealing surface 14 from the suction region of the impeller 10 relative to the adjoining Radseitenraum 20. The Radseitenraum 20 surrounds the adjacent to the suction port 12 axial end of the impeller 10 and forms an intermediate pressure chamber. The Radseitenraum 20 thus lies in the axial direction X between the suction port 12 and the outlet portion 22 of the impeller 10. The outlet region 22 of the impeller 10 is circumferentially surrounded by a pressure or spiral space 24, which is in communication with the pressure port 8. The spiral space 24 is separated from the Radseitenraum 20 by an annular gap 26.

In the case of the dirty water pump shown here, there is the problem that solids or contaminants from the spiral space 24 enter through the annular gap 26 into the wheel side space 20. In order to allow contamination to leave the Radseitenraum 20 again and thus prevent accumulation of solids or impurities in the Radseitenraum 20, which could lead to a blockage of the impeller 10, several measures are taken according to the invention. Thus, on the one hand, the wear ring 16 on the sealing surface 14th provided with two diametrically opposed grooves 28. The grooves 28 extend in the circumferential direction inclined over the sealing surfaces 14. In this case, the grooves 28 are inclined so that they extend inclined to a plane perpendicular to the axis of rotation X cross-sectional plane. Further, a first longitudinal end 30 of the opposite second longitudinal end 32 of the groove 28 in the axial direction X is spaced by a dimension which is greater than the axial abutment region between the inner periphery of the seal 18 and the sealing surface 14. Here, the groove 28 to the outer periphery , ie facing the seal 18, opened. In this way, the first longitudinal end 30 of the groove 28 is open to the Radseitenraum 20, while the second longitudinal end 32 is open to the suction side, ie to the opening 6 of the housing 4. The groove 28 thus establishes a connection between the suction side and the wheel side space 20. The inclination of the groove 28 is selected so that in the direction of rotation D, the first longitudinal end 30 is the front end of the groove 28. Upon rotation of the impeller 10, liquid is moved with solids from the Radseitenraum 20 through the grooves 28 into the suction region of the opening 6 of the pump housing 4, so that solids and impurities are led out of the Radseitenraum 20. This is done on the one hand due to the inclination of the groove 28 in the direction mentioned and the rotation of the impeller 10 and the other by the pressure difference between the Radseitenraum 20 and the suction region of the impeller 10. The pressure in Radseitenraum 20 is higher than the suction pressure of the impeller 10 and less than the output side pressure of the impeller 10th

A second measure essential to the invention is the arrangement of means for generating turbulence in the interior of the Radseitenraumes 20. The means for generating turbulence in this example, a wave-shaped axial surface 34 of the sealing ring 18. The axial surface 34 of the sealing ring 18 limits the Radseitenraum 20 their lower end. The surface 34 is provided with alternating troughs 36 and crests 38. The wave troughs 36 and wave mountains 38 are distributed uniformly over the circumference of the sealing ring 18. Furthermore, the wave troughs 36 are formed so that they extend from the outer periphery of the sealing ring 18 obliquely to the axis of rotation X. Ie. the wave troughs 36 and peaks 38 have on the inner circumference of the axial surface 34 their maximum height. Ie. the axial distance between wave troughs 36 and wave crests 38 is at the inner periphery of the surface 34 maximum. There is essentially no waveform on the outer circumference. Ie. the wave troughs 36 extend downwardly from the outer periphery of the surface 34 toward the inner circumference. The wave crests 38 lie in a plane with the outer circumference of the surface 34.

The wave shape of the surface 34 results in turbulence in the impeller side space 20 as the impeller 10 rotates, which results in circumferential movement of the liquid in the impeller side space 20. These cause impurities and solids not to agglomerate, but individually with liquid inside the impeller side space Distribute 20. Thus, such solids and contaminants can be dissipated individually through the grooves 28 without settling in the Radseitenraum 20.

A third measure is the arrangement of means for crushing solids in the region of the annular gap 26 between the spiral space 24 and the Radseitenraum 20. The means for comminuting solids are formed by four recesses 40 which are formed in an annular surface 42 which the annular gap 26 limited to its inner circumference. The annular surface 42 on the outer circumference of the impeller 10 is radially opposite an inner peripheral surface 44 of the pump housing 4, so that the inner peripheral surface 44 limits the annular gap 26 on its outer periphery. The recesses 40 are directed radially inwards and have a semicircular cross-section. The recesses 40 are parallel over their axial length to the rotation axis X a constant cross-section, so that they have the shape of a half-circular cylinder. On the inner peripheral surface 44, a further recess 46 is arranged beyond. The recess 46 is directed radially outward and open to the inner circumference of the inner peripheral surface 44. The one recess 46 is located so that the recesses 40 sweep the recess 46 during rotation of the impeller 10. Thus, a shearing action between the recesses 40 and the recess 46 is achieved, so that impurities, such as fibers, are comminuted between the recesses 40 and the recess 46 by shearing the passage of the annular gap 26, so that the solids in comminuted form in the Radseitenraum 20 enter and then exit from this through the grooves 28 later.

The one recess 46 on the inner peripheral surface 44 is arranged in the region of the spiral space 20, at which the smallest pressure difference to the Radseitenraum 20 prevails. This is in the region of the circumferential end 48 of the pressure or spiral space 24, which faces away from the outlet 50 with the pressure port 8 in the circumferential direction. Ie. the recess 46 is spaced in the direction of rotation D of the impeller 10 of the outlet 50 in this example by an angle of about 45 °.

By the comminution of solids by means of the recesses 40 and 46 in the annular gap 26 and the generation of turbulence in the Radseitenraum by the corrugated surface 34 of the sealing ring 18 and the arrangement of the grooves 28 on the sealing surface 14, an optimized removal of solids, which enter the Radseitenraum 20, ensures the suction of the impeller 10 and unwanted blocking of the impeller 10 by solids in the Radseitenraum 20 are largely prevented.

LIST OF REFERENCE NUMBERS

2

- Drive motor

4

- Pump housing

6

- opening

8th

- discharge nozzle

10

- Wheel

12

- Suction mouth

14

- sealing surface

16

- Wear ring

18

- sealing ring

19

- Inner circumference

20

- Radseitenraum

22

- Exit area

24

- Spiral space

26

- annular gap

28

- grooves

30

- 1. longitudinal end of the groove 28th

32

- 2nd longitudinal end of the groove 28th

34

- Axial surface of the sealing ring 18th

36

- wave troughs

38

- wave mountains

40

- recesses

42

- Ring surface

44

- Inner peripheral surface

46

- recess

48

- circumferential end

50

- outlet

X

- rotation axis

D

- direction of rotation

Claims (15)

1. A waste water pump with an impeller (10) which comprises a suction port (12) with a sealing surface (14) which annularly surrounds this and which bears on a stationary seal (18), characterised in that at least one groove (28) is formed in the sealing surface (14) and extends beyond a bearing-contact region of the seal (18) on the sealing surface (14) and with a first end (30) is in connection with an impeller side chamber (20) and with a second opposite end (32) is in connection with the suction side of the impeller (10) and that means for producing turbulences are arranged in the impeller side chamber (20) adjacent the seal (18).
2. A waste water pump according to claim 1, characterised in that the means (34) for producing turbulences are formed on the seal (18).
3. A waste water pump according to claim 2, characterised in that the seal (18), facing the impeller side chamber (29), is provided with a structured or wave-like surface (34).
4. A waste water pump according to claim 3, characterised in that the seal (18) is designed in an annular manner and the wave-like surface (34) is situated on an axial end-side of the seal (18).
5. A waste water pump according to one of the preceding claims, characterised in that the sealing surface (14) is formed on an outer peripheral surface of the impeller (10) and is surrounded by the seal (18) on the outer periphery.
6. A waste water pump according to one of the preceding claims, characterised in that the sealing surface (14) and the seal (18) bear radially on one another.
7. A waste water pump according to one of the preceding claims, characterised in that the at least one groove (28) extends in the rotation direction (D) of the impeller (10), inclined in a manner such that its end (30) which is at the front in the rotation direction (D) faces the impeller side chamber (20).
8. A waste water pump according to one of the preceding claims, characterised in that the groove (28) only extends in a peripheral part-region of the sealing surface (14).
9. A waste water pump according to one of the preceding claims, characterised in that means (40, 46) for fragmenting solid matter are formed in an annular gap (26) which connects the impeller side chamber (20) to a spiral chamber (24) surrounding the impeller (10).
10. A waste water pump according to claim 9, characterised in that the annular gap (26) is formed between an outer annular surface (42) on the peripheral of the impeller (10) and a radially oppositely lying inner peripheral surface (44) of a spiral housing (4) surrounding the impeller (10).
11. A waste water pump according to claim 10, characterised in that at least one radially inwardly directed recess (40) is formed in the annular surface (42).
12. A waste water pump according to claim 11, characterised in that several radially inwardly directed recesses (40) are formed in the annular surface (42) and are preferably uniformly distributed over the periphery.
13. A waste water pump according to one of the claims 10 to 12, characterised in that a radially outwardly directed recess (46) is formed in the inner peripheral surface (44) which lies opposite the annular surface (42).
14. A waste water pump according to claim 13, characterised in that the recess (46) in the inner peripheral surface (44) of the spiral housing (4) is situated in the region of that peripheral end (48) of the spiral chamber (24) which is away from an outlet (50).
15. A waste water pump according to one of the claims 10 to 14, characterised in that the recess (44; 46) has a semicircular cross section.

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