EP1161630B1 - Comminuting pump - Google Patents

Abstract

The invention relates to a comminuting pump for delivering sewage water that contains solid matter which is configured as a rotating positive-displacement pump, preferably as an eccentric screw pump (1). The pump comprises an electric motor and a pump case (1) which has a fixed pump stator (2) and an eccentrically mounted pump rotor (3). According to the invention, a comminuting device consisting of at least one fixed blade (5) and of at least one rotating blade (6) is provided on the pump, whereby the pump rotor (3) and the rotating blade (6) of the comminuting device are arranged on a shaft of the electric motor. The blades (5, 6) are configured as discs which are approximately concentric in relation to one another, which are arranged one above the other, and in which cutting passages are configured as circular holes that overlap in an at least partial manner in at least one angular position of the rotating blade (6).

Description

Comminution pump for conveying solids containing Wastewater, as a rotating displacement pump, with an electric motor, with a pump housing, a fixed pump stator and an eccentrically mounted or driven one Pump rotor and with a shredding device from at least one fixed and at least one rotating knife, the crushing device over the end remote from the drive shaft of the electric motor of the pump rotor is driven.

So far, conventional sewage pumps have predominantly been used Centrifugal pumps application. In order to be able to convey solids, Centrifugal pumps must be fitted with impellers that are proportional have high blades. With the eligibility of Solids enter automatically due to the bucket height high output, which is a corresponding interpretation of the Engines required. Because sewage pumps have long downtimes have, is the design of such pumps with large motors relatively uneconomical.

To create pumps that only pump small quantities, inexpensively comminution pumps and are not clogged developed which cutting devices on the suction side are upstream. These pumps allow the use of Impellers with lower blades and smaller motors Power.

Often such crushing pumps are said to be in pipelines promote that are thin and long for cost reasons and generate high hydraulic losses. For this reason you are often forced to design the pump for larger delivery heights, what only by increasing the diameter of the blades and is possible by increasing the required engine power, because it is inherent to the operation of the centrifugal pump that Delivery volume increases almost to the same extent with the delivery head, the pump has a relatively flat characteristic head over the volume flow conveyed.

Positive displacement pumps offer a way out of this situation in addition to small flow rates and any pressures also the Have the advantage of a relatively high efficiency.

A positive displacement pump with a shredding device is, for example known from DE 44 13 940 A1. This publication relates to a slurry pump, which is used as an eccentric screw pump with a submersible electric motor and an upstream Disintegrator or an upstream shredding device is designed to destroy solid parts. This eccentric screw pump is a those in which the pump stator is fixed, and the Axis of rotation of the pump rotor with respect to the axis of the pump stator is eccentric. With this proven design of single-spindle pumps, compared to pumps with a vibrating stator are structurally relatively simple and robust, it is relatively problematic, the pump rotor on the same Arrange electric motor shaft, with which the rotating Part of the shredder is driven as it is according to prevailing opinion, is not possible from the eccentric vibrating rotor the rotating motion on the to transfer the corresponding element of the shredding device.

DE 44 13 940 A1 therefore proposes the submersible electric motor the pump with a shaft protruding on both sides to execute, on the one hand the single-spindle pump through a Pump is designed with a fixed stator on a Side of the submersible electric motor is mounted and with this means a suction piece is connected, and on the other hand the To arrange a comminution device for the submersible electric motor, via a deflection line with the suction port of the pump is connected, the suction nozzle laterally, d. H. across to Extension of the pump rotor opens into the pump housing.

This makes the pump structurally very complex, the electric motor must be sealed on both sides against the ingress of water what is relatively expensive and the whole Pump becomes bulky and unwieldy.

An eccentric screw submersible pump is from utility model DE 93 14 746 U1 known of an agitator for homogenization of components sedimented in the pump medium is connected upstream. The blades of the agitator are there Pump described attached directly to the pump rotor, wherein an inclination of the agitator blades in connection with an eccentric rotary movement is particularly effective Homogenization of the pump medium should cause.

The pump described in the utility model DE 93 14 746 U1 is not, however, used to pump waste water with solid components suitable. For example, the pump would have to do this be able to shred larger rags or the like. This is only with one or more cutterbars rotating counter-rotating knives.

A comminution pump according to the preamble of claim 1 known for example from utility model DE-GM 19 23 821. In the eccentric screw pump described there a cutting unit in an anteroom on the suction side of the stator arranged, which consists of a firmly connected to the pump housing Knife bar and an elastic one, circumferential cutter bar. The circumferential knife bar, the symmetrical two-wing with a hole in the middle is with the help of tongue and groove on an axial The peg is pushed onto the rotor and is replaced by a package of Disc springs pressed against the fixed cutter bar. Due to the construction of the cutting unit, they are necessary Eccentric screw pump with relatively large passage areas provided for the pumped medium, which creates the risk of clogging should be reduced. Because of the size of the Passage areas for the pumped medium can, however, be proportionate large or thick strand-like foreign bodies in penetrate the pump vestibule, so that the pump under certain circumstances an extremely high torque must be applied to penetrating To break up or shred foreign objects. At worst, such solids can block the Run the pump.

A similar is from the utility model DE-GM 19 50 502 Eccentric screw pump known, in which the cutting unit a cutting ring firmly connected to the pump housing, the opening of which has a serrated or wavy cutting edge, and a cooperating cutting wheel with a spiral spoke formed as a knife edge. This construction also suffers from that described above Disadvantage that the passage cross section between Cutting ring and cutting wheel at the entry point between the rotor and stator is relatively large.

From DE 44 38 841 C1 is a pump with a cutting device known in which the pump impeller as a centrifugal pump trained pump with several cutting blades is that are moved relative to fixed counter knives. The pump impeller has a hollow shape, the inside of which Media flow leading, outwardly projecting, rotatioshaped symmetrical structure on which the rotating cutting knife are arranged, which have the fixed counter knife a corresponding geometric structure. That in the DE 44 38 841 C1 described cutting unit can only with one Centrifugal pump interact and is intended for such a especially since the pump impeller is part of the cutting device is.

The object of the invention is therefore a comminution pump of the type mentioned in such a way that they largely free of blockages and undisturbed operation the pump even in the presence of long-fiber and guaranteed solid components in the pumped medium.

The object is achieved in that the knives are superimposed Discs are formed, which in at least an angular position of the rotating knife approximately concentric are arranged to each other that the knife cutting passages have, of which at least two are in at least an angular position of the rotating knife at least partially overlap, and that the cutting passages form arcuate or crescent-shaped cutting edges.

In the pump according to the invention, this is from the electric motor and its drive shaft remote end of the pump housing formed as a suction side, the crushing device in a special suction port or in the pump housing itself can be integrated. Through the training according to the invention the knife as one on top of the other and rotating on top of each other Discs with cutting passages, the circular arc or form sickle-shaped cutting edges, the can of material sucked into the pump only through the cutting passages of the fixed knife in the pump housing or in penetrate an intake manifold if they are on top of each other arranged cutting overlaps overlap. Another turn of the rotating knife causes cutting or Shatter the penetrated object. In particular, that the cutting passages are arcuate or crescent-shaped Forming cutting edges becomes a silhouette Infeed of the cutting passes, so that the Solids are cut like scissors. there is the eccentric movement in an advantageous manner of the pump rotor, which uses the silhouette of the work which supports cutting passages.

According to a preferred embodiment of the invention, the Cutting passages are designed as circular holes. Depending on Arrangement of the holes on the discs will make the cutting passages from a full circular opening over a Deliver elliptical opening, in connection with the eccentric movement of a disk a particularly advantageous Shearing and cutting effect on the material to be shredded is exercised.

The centers of the holes are expediently at least in an angular position of the rotating knife on a concentric to the center of the disks (imaginary) Arranged circular arc.

A particularly favorable cutting effect is surprisingly achieved when the number of cutting passes in the standing knife is larger than in the rotating knife. A cut passage is preferred in the standing diameter more than provided in the rotating knife, so that only in one angular position of the rotating knife two Cutting passages overlap.

The rotating knife is preferably in the conveying direction of the medium to be pumped arranged downstream. This takes place besides the rotating a slight radial movement because it is the Traces the movement of the pump rotor. The rotating knife also preferably has a smaller diameter than that fixed knife. Due to the radial movement of the rotating Knife is surprisingly an improved size reduction causes, in addition, the gap between the knives cleaned.

The cutting passages of the fixed knife downstream and form in this direction beveled cutting edges against which the solids like with a pair of scissors. It is particularly beneficial when the cutting passages of the rotating knife expand downstream so that this and the cutting passages of the fixed knife on both sides of the plane between the knives are beveled symmetrically and one in apex located approximately in the plane between the knives form.

The formation of the knife in the manner described above and Way also has the advantage that this occurs when wear occurs can simply be sanded flat.

The disks preferably form a gap between them whose depth is adjustable in the axial direction.

It is particularly useful if the rotating knife over a transition piece connected to the front of the pump rotor, is preferably screwed.

For an optimal adjustment of the gap between the knives without guaranteeing expensive adjustment screws, this can be done rotating knives with the interposition of an elastomer body screwed to the pump rotor. That way it is also possible to adjust the gap dimension in the event of wear.

In the preferred embodiment of the invention It is provided that the knife in a suction side of the Pump provided conical nozzle are arranged. This For example, a nozzle can simply be attached to one end of the pump housing be flanged. Due to the angle of inclination of the cone the radii of the knives are determined.

The nozzle can for example be made of polyurethane or a be made of similar material and several stages of inclusion have different knife sizes.

The pump according to the invention is expediently used as an eccentric screw pump educated.

The invention is described below with reference to one of the drawings illustrated embodiment explained.

Fig. 1

eine Teilansicht des Pumpengehäuses im Bereich der Saugseite mit darin angeordneter Zerkleinerungseinrichtung im Schnitt,

Fig. 2

eine Draufsicht auf das feststehende Messer, von außen,

Fig. 3

einen Schnitt durch das feststehende Messer,

Fig. 4

eine Draufsicht auf das rotierende Messer, von innen,

Fig. 5

einen Schnitt durch das in Fig. 4 gezeigte rotierende Messer und

Fig. 6

eine schematische Ansicht, aus welcher die Übereinanderanordnung von feststehendem und rotierendem Messer ersichtlich ist, gegen den Förderstrom des zu pumpenden Mediums betrachtet.

Show it:

Fig. 1

2 shows a partial view of the pump housing in the area of the suction side with a comminution device arranged therein,

Fig. 2

a top view of the fixed knife, from the outside,

Fig. 3

a cut through the fixed knife,

Fig. 4

a top view of the rotating knife, from the inside,

Fig. 5

a section through the rotating knife shown in Fig. 4 and

Fig. 6

is a schematic view, from which the superimposition of fixed and rotating knife can be seen, viewed against the flow of the medium to be pumped.

The electric motor, drive shaft, coupling rod, joints, Pump housing 1, pump stator 2 and pump rotor 3 existing Pump of conventional design is in the for the sake of simplicity Figures not shown in full. The pump rotor 3 is in a manner known per se within the pump stator 2 on the shaft of an electric motor by means of one to two Articulated attached coupling rod driven. Doing this the pump rotor 3 within the pump housing 1 a rotating and slightly radial movement.

In Fig. 1 the suction side of the pump is shown, wherein in a funnel-shaped suction nozzle 4 a fixed knife 5 and a rotating knife 6 are arranged, both as circular discs are formed. The suction nozzle 4 and the end of the pump housing 1 remote from the electric motor are coupled to one another via a flange connection 7.

The fixed knife 5 is via an Allen screw 8 with the interposition of an elastomer body 9 via a transition piece 10 screwed to the end face 11 of the pump rotor 3, the hexagon socket screw 8 through the elastomer body 9 and the transition piece 10 into a not shown Internal thread of the pump rotor 3 engages.

The elastomer body 9 ensures an elastic gap setting between the fixed knife 5 and the rotating one Knife 6, the rotating knife 6 by adjusting the Allen screw 8 is adjustable.

The head of the Allen screw 8 protrudes into one central bore 12 of the fixed knife, its diameter is larger than the diameter of the screw head to allow the radial movement of the rotating knife 6.

For this reason, the diameter of the rotating knife 6 chosen smaller than the inner diameter of the suction nozzle 4 and the fixed knife 5, which on the rotating Collar 13 of the suction nozzle 4 is screwed.

So that the suction nozzle, which is preferably made of polyurethane 4 can be used for different knife sizes, for example a circumferential in the area of a smaller diameter Web 14 may be provided when sawing off the suction nozzle 4 below the web 14 the function of the collar 13 takes over.

As can be seen in FIGS. 2 to 6, the knives 5, 6 provided with cutting passages 15, 16, with 16 the Cutting passages in the rotating knife 6 and with 15 die Cutting passes designated in the fixed knife 5 are.

The cutting passages 15, 16 are designed as circular holes and in the knives 5, 6 in superimposed ones Half-knife areas arranged so that the cutting passages 15, 16 permeable in certain angular positions of the knives 5, 6 are, d. H. overlap. Due to the geometry of the Holes form the cutting passages 15, 16 each in the shape of a circular arc or sickle-shaped cutting edges.

The centers of the cutting passages 15, 16 of both fixed knife 5 and the rotating knife 6 are all on a common arc around the center the knife 5, 6 arranged. In the illustrated embodiments is the fixed knife 5 with six cutting passages 15 provided, whereas the rotating knife 6 is provided with five cutting passages 16 so that, like this 6 can be seen, only in an angular position of the rotating knife 6 there are two cutting passages 15, 16 completely overlap and thus an open passage form for the medium to be pumped. Of the remaining cutting passages 15, 16 form in the angular position shown rotating knife 6 only two more, one pass, whereas the others are arranged side by side and do not create a passage for the medium to be pumped.

It would of course also be possible to arrange and Number of cutting passes 15, 16 on the knives 5, 6 to choose identical, so that in an angular position of the rotating knife 6 overlap all cutting passages 15, 16 would.

However, the chosen arrangement has proven to be advantageous in this way, the one from the cutting passages rotates 15, 16 formed passage in the direction of rotation of the rotating knife 6.

As can be seen in the sectional views, taper the cutting passages 15 of the fixed knife 5 in the conveying direction of the medium to be pumped, whereas the Cutting passages 16 of the rotating knife 6 in the conveying direction expand the medium to be pumped in a funnel shape, see above that this and the cutting passages 15 of the fixed Knife 5 in the direction of between the knives 5, 6 form cutting edges that run towards each other, the material to be cut into one or the other Let direction slip.

LIST OF REFERENCE NUMBERS

1

pump housing

2

pump stator

3

pump rotor

4

suction

5

fixed knife

6

rotating knife

7

flange

8th

Allen screw

9

elastomer body

10

Transition piece

11

Front of the pump rotor

12

central hole

13

collar

14

all-round bridge

15, 16

Cutting passages

Claims (12)

1. Comminuting pump for conveying waste water containing solids, in the form of a rotating positive displacement pump, having an electric motor, having a pump casing, having a fixed pump stator and an eccentrically mounted rotor and also having a comminuting device comprising at least one fixed and at least one rotating blade, wherein the comminuting device is driven via the end of the pump rotor remote from the drive shaft of the electric motor, characterised in that the blades (5, 6) are configured as superimposed discs, which, in at least one angular position of the rotating blade (6), are arranged approximately concentrically with respect to one another, in that the blades (5, 6) have cut-through passages (15, 16) of which at least two overlap at least partially in at least one angular position of the rotating blade (6), and in that the cut-through passages (15, 16) form circular arc-shaped or sickle-shaped cutting edges.
2. Comminuting pump according to claim 1, characterised in that the cut-through passages (15,16) are in the form of circular holes.
3. Comminuting pump according to one of claims 1 and 2, characterised in that the midpoints of the holes, at least in one angular position of the rotating blade (6), are arranged on a circular arc running concentrically with respect to the midpoint of the discs.
4. Comminuting pump according to any one of claims 1 to 3, characterised in that the number of cut-through passages (15) in the fixed blade (5) is larger than in the rotating blade (6).
5. Comminuting pump according to any one of claims 1 to 4, characterised in that the rotating blade (6) is arranged downstream in the conveying direction of the medium to be pumped.
6. Comminuting pump according to any one of claims 1 to 5, characterised in that the cut-through passages (15) of the fixed blade (5) taper in a downstream direction and form chamfered cutting edges.
7. Comminuting pump according to any one of claims 1 to 6, characterised in that the cut-through passages (16) of the rotating blade (6) widen in a downstream direction.
8. Comminuting pump according to any one of claims 1 to 7, characterised in that the blades (5, 6) form between them a gap, the depth of which is axially adjustable.
9. Comminuting pump according to any one of claims 1 to 8, characterised in that the rotating blade (6) is connected, preferably screwed, by way of a transition piece (11) to the end face of the pump rotor (3).
10. Comminuting pump according to any one of claims 1 to 9, characterised in that the rotating blade (6) is screwed to the pump rotor (3) via the intermediary of a resilient member (9).
11. Comminuting pump according to any one of claims 1 to 10, characterised in that the blades (5, 6) are arranged in a conical connection piece provided on the suction side of the pump.
12. Comminuting pump according to any one of claims 1 to 11, characterised in that it is in the form of an eccentric spiral pump.

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