GB1568388A

GB1568388A - Pump with comminuating means at the inlet

Info

Publication number: GB1568388A
Application number: GB4887276A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1975-11-29
Filing date: 1976-11-24
Publication date: 1980-05-29
Also published as: AT362233B; JPS5267801A; FR2333140A1; ES453713A1; ATA881176A; JPS6059440B2; SE7613280L; FR2333140B1; SE457276B; IT1074990B

Description

(54) A PUMP WITH COMMINUTING MEANS AT THE INLET (71) I, ALBERT BLUM, Scheiderhöhe, Lohmar. Rheinland, Federal Republic of Germany, of German nationality, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a pump of the kind (herein called "the kind defined") comprising a housing with an inlet and comminuting means to act upon material at the inlet.

Pumps of the kind defined are often used as sewage pumps in submersible assemblages each with an electric motor and a pump connected therewith.

Since as a rule sewage contains fibrous materials, vegetable components, lumps of matter, textiles and the like, many proposals have already been made for devices by which materials mixed with the conveyed medium are comminuted before or at entry into the pump.

Many such comminuting devices are inefficient or considerably increase the power consumption of the pumps, and therefore the invention is intended to provide an improved pump of the kind defined.

According to the invention a pump of the kind defined is characterised in that at the inlet there are two mutually-co-coperative members such that during operation one is stationary and the other is rotary and thereby openings for the passage of said material are periodically afforded and obturated, the said two members also constitute the comminuting means, and the stationary member is an inlet tube with at least one end profile, and the rotary member is accommodated in the tube and has at least one peripheral formation to co-operate with the or each said end profile for periodically affording and obturating said passages and for comminuting said material.

Such a pump may be made to operate so that after every cutting of the admixtures fed to the comminuting means under the influence of the suction effect of the conveyed medium there occurs a forcing back of these admixtures out of the region of the comminuting means. Thus the feed of the admixtures to the comminuting means can take place intermittently, which may possibly also be achieved if the two members cause the generation of a pulsating suction flow.

Advantageously the rotary member is secured to and rotates with the pump shaft, and possesses on its periphery adjoining the tube a formation in undulatory or saw-tooth form corresponding to or somewhat greater than undulations or serrations at the or each free end of the tube, in amplitude. It is advisable that the number of the undulations or serrations at the end of the tube should differ from that of the undulations or serrations of cutting edges on the rotary member, the latter preferably having a number of undulations greater than the number of the undulations on the tube; a ratio of 3 to 2 or 5 to 3 has proved advantageous for these numbers of undulations.

A right-cylindrical formation of the tube is expedient if it is to be possible for the rotary member to be adjustable in the axial direction in relation to the tube, although this can have the result that one or both members must be replaced after only comparatively slight wear, if a close fit is required for a good comminution performance.

If, however the tube is of conical formation, at least on its surface co-operating with the rotary member, the spacing of the cooperating surfaces and edges can be variable by axial displacement of one of the said two members in relation to the other, for example under the influence of spring force so that the two members constantly exert slight pressure against one another.

The tube can have its conical part tapering outwards or inwards with respect to the hous ing, and the tube can protrude inwards or outwards or both inwards and outwards from the suction opening. It may advantageously protrude into a free space between a hub of a pump wheel or impeller and the inner edges of vanes thereof, and this hub may form the rotary member, at least over a part of its length. Such a formation, with the tube protruding inwards into the pump housing is advantageous with a "closed" impeller.

The conicity, if any, of the tube can vary over its length, especially towards both ends, and then it can be expedient to make the rotary member in at least two parts. The profiling of the tube may extend over nearly the whole length of the tube, and then the conicity is expediently constant over the whole length of the tube piece.

How the invention may be put into practice is explained in greater detail hereinafter by reference to the accompanying drawings, wherein: Figure 1 shows the foot part of a submersible sewage pump assemblage, partially in section, Figure 2 shows a detail in a section approximately along the line 2-2 in Figure 1, Figure 3 shows diagrammatic developments of undulations, Figure 4 shows a preferred rotary member, in perspective representation, with five undulations according to Figure 3, and Figures 5 to 8 show modified forms of embodiment.

The pump assemblage of Figure 1, which can comprise an electric motor and a pump coupled therewith, accommodated in one common housing 11, has a pump chamber 12 into which a motor shaft 13 protrudes to act as a pump shaft. On this shaft 13 is an impel lerorpumpwheel 14 with free edges of vanes 141 at a short distance above a serrated plate 121 which surrounds a suction opening 15.

A tube 16 constitutes a stationary member of comminuting means at the inlet through the suction opening 15. In this tube 16 is accommodated a rotary member 17 provided on its periphery with an undulatory fin 171 which reaches as far as the internal periphery of the tube 16. The member 17 is secured upon an extension of the shaft 13 and rotates therewith. A free edge 161 of the tube 16 possesses a profile which is undulatory in development (Figure 3). The undulation of the tube edge 161 and that of the fin 171 are both represented diagrammatically in development in Figure 3. Here the undulation of the edge of the fin 171 is indicated by the solid line, and the end profile of the tube edge 161 by the dot-and-dash line.

When the pump is running a relative displacement constantly takes place between the end edge 161 of the tube 16 and the fin 171 of the member 17. During the rotation of the member 17, as a result of the displacement of the undulatory profiles in relation to one another, passage openings for the conveyed medium are periodically afforded and obturated, that is constantly alternately cleared and covered over again. Thus the flow through the wave troughs 162, 163, 164 of the profile at the end of the tube 16, which are to be regarded as entry openings, constantly fluctuates according to the passage cross-section cleared by the undulatory fin 171 on the rotary member 17. The medium and admixtures are sucked into these entry openings by the suction effect of the pump.

Then as soon as the rising flank 175, which is forward in the direction of rotation (arrow 172), of the undulatory cutting fin 171 runs past the edge 165 of the stationary profile 16, the parts of the admixtures sucked into the entry opening are cut off. Only slight cutting forces are necessary for this purpose, since the inclination of the mutually engaging cutting edges in relation to one another is slight.

The following descending flank of the undulatory cutting fin 171 then, before it again clears the entry opening, presses the forward edge of the following admixture piece at least to a slight extent out of the immediate region of the cutting edges. Thus there is a constant alteration between suction, cutting-off, possibly pressing away, and a renewed suction, cutting-off, and so forth, while at the same time a constant alternate opening and closing of the entry openings takes place. Blockages of the entry openings are effectively prevented by the resulting pulsating flow. The pressing-away of the sucked-in parts and the generation of a pulsating flow are favoured because the basic body of the rotary member 17, as indicated in perspective in Figure 4, as a whole is shaped to suit the undulatory formation of the cutting fin 171.Figure 4 shows a rotary member 17 having five undulations, in accordance with the example according to Figure 3, in perspective representation.

A pump assemblage, with parts as illustrated in Figure 5, can consist in known manner of an electric motor and a pump coupled therewith and both arranged in a common housing 51. In known manner the motor shaft 53 extends to form a pump shaft on which is an impeller or pump wheel 54 in a pump chamber 52. The free edges of the vanes 541 of the pump wheel 54 move at a short distance above a serrated plate 521 which is arranged in the bottom of the pump chamber 52 and surrounds the suction opening 55 of the pump housing.

Into the suction opening 55 is inserted a tube 56 which tapers conically outwards in its part 561 protruding downwards beyond the bottom of the pump chamber. The lower edge 561 of the tube 56 is profiled in undulatory form in development and upon the end of the motor shaft 53 extending through the pump wheel 54 there is a rotary member 57, of conical overall outline, with an edge 571 of undulatory formation. The conicity of the member 57 is adapted to the conicity of the part 561 of the tube 56. Between the member 57 and the end of the shaft 53 are dished springs 59 by which the member 57 is kept in abutment on the inner wall of the tube 56 by spring pressure.

Figure 6 illustrates a modification in which the tube 66, arranged in the bottom of the pump chamber 62 of the housing 61 and seated in the suction opening 65 surrounded by a spiral plate 621, has an inner surface which flares outwards from the housing 61, that is to say this inner surface widens conically outwards in the outwardly protruding part 661 of the tube 66. The member 67 with its undulatory edge 671, seated on the lower end of the motor shaft 63 is correspondingly of conical formation. The member 67 is displaceable in the axial direction on an extension piece 631 of the shaft 63, and is pressed against the concial surface in the tube part 661 by dished springs 69.

Figure 7 shows a tube 76, inserted into the suction opening 75 situated in the bottom of the housing 71, with its profiled edge 761 extending inwards into the pump chamber 72. The profiled edge 761 extends into a space which remains free between the inner ends of the vanes 741 of the pump wheel 74.

A rotary member 77, the conicity of which is adapted to the conicity of the tube 76, is pressed against the tube 76 by dished springs.

Figures 8 illustrates a tube 86 inserted into the housing bottom 81 and comprising both an outwardly-protruding part 861 and an inwardly-protruding part 862. Internally the tube 86 is of constant conicity over its whole length,for the passage of said material are periodically afforded and obturated. The said two members also constitute comminuting means, and the stationary member is an inlet tube with at least one end profile, and the rotary member is accommodated in the tube and has at least one peripheral formation to co-operate with the or each said end profile for periodically affording and obturating said openings and for comminuting said material.

WHAT I CLAIM IS: 1. A pump of the kind comprising a housing with an inlet and comminuting means to act upon material at the inlet, characterised in that at the inlet there are two mutuallyco-operative members such that during operation one is stationary and the other is rotary and thereby openings for the passage of said material are periodically afforded and obturated, the said two members also constitute the comminuting means, and the stationary member is an inlet tube with at least one end profile, and the rotary member is accommodated in the tube and has at least one peripheral formation to co-operate with the or each said end profile for periodically affording and obturating said openings and for comminuting said material.

2. A pump according to Claim 1, wherein the said two members serve for the generation of a pulsating suction flow.

3. A pump according to Claim 1 or 2, wherein the said formation is on a portion of the rotary member in the form of a cutting edge or fin reaching as far as the inner surface of the tube.

4. A pump according to Claim 1, 2 or 3, wherein the or each said profile is undulatory in development.

5. A pump according to claim 1, 2 or 3, wherein the or each said profile is of sawtooth form in development.

6. A pump according to Claim 1, 2, 3, 4 or 5 wherein the said formation is undulatory in development.

7. A pump according to Claim 1, 2, 3, 4, or 5, wherein the said formation is of sawtooth form in development.

8. A pump according to any one or more of Claims 1 to 7, wherein the or each said formation has serrations or undulations which correspond approximately in amplitude to undulations of the or each said profile.

9. A pump according to any one or more of Claims 1 to 8, wherein the or each said profile has undulations or serrations which differ in number from undulations or serrations of the or each said formation.

10. A pump according to Claim 9, wherein the number of the undulations or serations of the or each said formation is greater than the number of the undulations or serrations of the or each said profile on the tube.

11. A pump according to Claim 10, wherein the number of the undulations or serrations of the or each said formation is in the ratio of about 3:2 or about 5:3 to the number of the undulations or serrations at the or each said profile on the tube.

12. A pump according to any one or more of Claims 1 to 11, wherein the tube is of conical formation at least on its surface for co-operation with the rotary member, and the distance of the said two members from one another is variable.

13. A pump according to Claim 12, wherein at least one of the said two members is displaceable towards the other under the influence of spring force.

14. A pump according to Claim 12 or 13, wherein the tube conical surface tapers outwards from the housing.

15. A pump according to Claim 12 or 13, wherein the tube conical surface flares outwards from the housing.

16. A pump according to any one or more of Claims i to 15, wherein the tube

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. through the pump wheel 54 there is a rotary member 57, of conical overall outline, with an edge 571 of undulatory formation. The conicity of the member 57 is adapted to the conicity of the part 561 of the tube 56. Between the member 57 and the end of the shaft 53 are dished springs 59 by which the member 57 is kept in abutment on the inner wall of the tube 56 by spring pressure. Figure 6 illustrates a modification in which the tube 66, arranged in the bottom of the pump chamber 62 of the housing 61 and seated in the suction opening 65 surrounded by a spiral plate 621, has an inner surface which flares outwards from the housing 61, that is to say this inner surface widens conically outwards in the outwardly protruding part 661 of the tube 66. The member 67 with its undulatory edge 671, seated on the lower end of the motor shaft 63 is correspondingly of conical formation. The member 67 is displaceable in the axial direction on an extension piece 631 of the shaft 63, and is pressed against the concial surface in the tube part 661 by dished springs 69. Figure 7 shows a tube 76, inserted into the suction opening 75 situated in the bottom of the housing 71, with its profiled edge 761 extending inwards into the pump chamber 72. The profiled edge 761 extends into a space which remains free between the inner ends of the vanes 741 of the pump wheel 74. A rotary member 77, the conicity of which is adapted to the conicity of the tube 76, is pressed against the tube 76 by dished springs. Figures 8 illustrates a tube 86 inserted into the housing bottom 81 and comprising both an outwardly-protruding part 861 and an inwardly-protruding part 862. Internally the tube 86 is of constant conicity over its whole length,for the passage of said material are periodically afforded and obturated. The said two members also constitute comminuting means, and the stationary member is an inlet tube with at least one end profile, and the rotary member is accommodated in the tube and has at least one peripheral formation to co-operate with the or each said end profile for periodically affording and obturating said openings and for comminuting said material. WHAT I CLAIM IS:

1. A pump of the kind comprising a housing with an inlet and comminuting means to act upon material at the inlet, characterised in that at the inlet there are two mutuallyco-operative members such that during operation one is stationary and the other is rotary and thereby openings for the passage of said material are periodically afforded and obturated, the said two members also constitute the comminuting means, and the stationary member is an inlet tube with at least one end profile, and the rotary member is accommodated in the tube and has at least one peripheral formation to co-operate with the or each said end profile for periodically affording and obturating said openings and for comminuting said material.

16. A pump according to any one or more of Claims i to 15, wherein the tube

protrudes outwards from a suction opening of the housing.

17. A pump according to any one or more of Claims 1 to 16, wherein the tube protrudes into the housing from a suction opening thereof.

18. A pump according to Claim 17, wherein the tube protrudes inwards into a free space between a hub and the inner edges of vanes of an impeller.

19. A pump according to any one or more of Claims 1 to 18, comprising an impeller with a hub which forms the said rotary member, at least over a part of its length.

20. A pump according to Claim 18 or Claims 18 and 19, wherein the tube protrudes both outwards from and also inwards into the housing.

21. A pump according to Claim 20, wherein the tube has an end profile on both of its ends.

22. A pump according to Claim 12, or Claim 12 and any one or more of Claims 13 to 21, wherein the conicity of the tube is variable over its entire length.

23. A pump according to any one or more of Claims 1 to 22, wherein the rotary member is made in at least two parts.

24. A pump according to any one or more of Claims 1 to 23, wherein the profile of the tube extends from one end over substantially the whole length of the tube.

25. A pump constructed substantially as hereinbefore described with reference to and as shown in Figure 1, 5, 6, 7, or 8 of the accompanying drawings.