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Title:
CUTTER PUMP WITH QUICK-ASSEMBLY CUTTING UNIT AND IMPELLER
Document Type and Number:
WIPO Patent Application WO/2018/100488
Kind Code:
A1
Abstract:
The invention is a cutter pump comprising an impeller (20) mounted on a driving shaft (30), a rotary cutting blade (50) mounted so that it is coaxial with said impeller (20) and rotates together with it, and a cutting plate (60) constrained to the pump body (14) and defining the cutting interface (T) together with said cutting blade (50). Said cutting blade (50) comprises a through axial opening (51) which is not threaded and is suitable for the insertion of said shaft (30), and wherein said cutting blade (50) and said impeller (20) are mechanically connected to said shaft (30) by means of at least one tab (32), so that they rotate integrally with each other and with said shaft (30) itself.

Application Number:
IB2017/057445
Publication Date:
June 07, 2018
Filing Date:
November 28, 2017
Export Citation:
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Assignee:
DRENO POMPE SRL (Via Umbria 15, Monselice, 35043, IT)
International Classes:
F04D7/04; B02C18/00; F04D29/22; F04D29/62
Foreign References:
JP2843270B21999-01-06
JPS5930587U1984-02-25
EP2813707A12014-12-17
JPH021490U1990-01-08
Attorney, Agent or Firm:
ROCCHETTO, Elena (Via Sorio 116, Padova, 35141, IT)
Download PDF:
Claims:
CLAIMS

1, Cutter pump comprising a pump body (14), an impeller (20) mounted on a driving shaft (30) and rotating inside a housing (11) provided in said pump body (14), a cutting unit (40) mounted coaxially with said impeller (20) and in turn comprising a cutting plate (60) constrained to the pump body (14) and a cutting blade (50) which rotates with respect to said cutting plate (60), mounted so that it is coaxial with said impeller (20) and rotates together with it, and wherein said cutting blade (50) and said cutting plate (60) cooperate with each other so as to define the cutting interface (T) through which the liquid to be transported is intended to flow, and wherein said cutting blade (50) comprises a through axial opening (51) which is not threaded and is suitable for the insertion of said shaft (30), and said impeller (20) comprises a through axial opening (21) for the insertion of said shaft (30), characterized in that said cutting blade (50) and said impeller (30) are mechanically connected to each other and to said shaft (30) by means of a single tab (32) inserted between said shaft (30) and said axial openings (21, 51) of said impeller (20) and of said cutting blade (50), in such a way that they rotate integrally with each other and with said shaft (30) itself,

and wherein one end (31) of said driving shaft (30) projects upstream of the cutting blade (50), said end (31) being threaded externally so as to allow at least one nut (70) to be screwed thereon, said nut being suited to lock said cutting blade (50) and said impeller (20) onto said shaft (30),

and wherein said cutting plate (60) is mounted between said impeller (20) and said cutting blade (50) and comprises a centre opening (61) at the level of the driving shaft (30) of the impeller (20), through which said cutting blade (50) and said impeller (20) come into contact with each other, and wherein said cutting blade (50) and said impeller (20) abut against each other thanks to the tightening action of said at least one nut (70).

2. Cutter pump (10) according to claim 1, characterized in that said cutting plate (60) is suited to be constrained to said pump body (14) at a selectable distance from said cutting blade (50).

Cutter pump (10) according to claim 2, characterized in that said pump body

(14) comprises at least one fixed portion (16) and at least one adjusting portion

(15) to which said cutting plate (60) is rigidly constrained, said adjusting portion (15) being suited to be rigidly constrained to said fixed portion (16) through fixing means (151), and wherein between said fixed portion (16) and said adjusting portion (15) there are adjustable spacer elements suited to selectively vary the position of said adjusting portion (15) with respect to said fixed portion (16) of the pump body (14), thus determining also the position of said cutting plate (60) with respect to said cutting blade (50).

Cutter pump (10) according to claim 3, characterized in that said adjustable spacer elements comprise one or more threaded dowels (17) which are distributed homogeneously and abut against said fixed portion (16) and are engaged in correspondingly threaded seats (152) created in said adjusting portion (15), and wherein screwing said dowels (17) more or less into said adjusting portion (15) determines the position of said adjusting portion (15) itself with respect to said fixed portion (16).

Description:
CUTTER PUMP WITH QUICK-ASSEMBLY CUTTING UNIT AND IMPELLER

DESCRIPTION

The present patent concerns cutter pumps, and in particular it concerns a cutter pump with quick-assembly cutting unit and impeller.

Pumps are known, which are intended for transporting liquids that contain solid materials, which happens quite often, for example, in the case of rainwater containing leaves and other solid and coarse material.

These pumps, commonly called cutter pumps, are equipped with a cutting unit which is installed on the suction side of the pump and serves the function of cutting the solid materials contained in the liquid in order to reduce said solid material to such a size as to allow it to pass through the pump without causing any clogging.

The cutting unit is constituted by a rotary cutting blade, which is mounted so that it is coaxial with the impeller of the pump and rotates together with it, and a cutting plate which is fixed with respect to the pump body and is mounted between the cutting blade and the impeller, and wherein the cutting interface is defined between said rotary cutting blade and said cutting plate.

The liquid to be transported flows according to an axial suction direction, passes through the cutting unit and then is discharged through the outlet duct in radial direction.

The cutting efficiency is determined by the clearance between the cutting blade and the cutting plate. Several types of cutter pump are known, which are provided with devices suited to adjust said clearance and lock the cutting unit in the desired position.

For example, pumps are known where said adjustment takes place during the assembly phase, through the insertion of spacer washers in the driving shaft, between the impeller and the cutting blade, and the successive adjustment of the position of the cutting plate with respect to the pump body. The correctness of this adjustment operation depends on the skills and expertise of the operator and cannot be reproduced exactly.

For example, cutter pumps of the type described in patent EP2147213 are also known, in which said adjustment operation is carried out by means of additional threaded screws inserted in the correspondingly threaded end of the shaft, upstream of the cutting blade with respect to the suction direction, and in which said cutting blade is in turn screwed onto the driving shaft.

The driving shaft, in particular, is made up of two portions that can be screwed onto each other, wherein one portion is mechanically fitted into a blind hole provided in said impeller, while the other portion is threaded externally, so that it can be engaged into a correspondingly threaded through axial opening provided in said cutting blade.

Even if this type of pump satisfactorily allows the clearance of the cutting unit to be adjusted in a repeatable way, it is rather complex to assemble and furthermore the correct operation of the adjusting system depends on the precision with which said components are made and assembled.

In order to overcome all of the drawbacks described above, a new type of cutter pump with quick-assembly cutting unit and impeller has been designed and constructed.

The main object of the present invention is to improve the known cutter pumps by simplifying and quickening the assembly of the cutter unit, in addition to reducing the number of its components.

It is another object of the present invention to simplify the operations intended to adjust the cutting efficiency.

The new cutter pump comprises a pump body, an impeller mounted on a driving shaft and rotating inside a housing created in said pump body and a cutting unit mounted so that it is coaxial with said impeller.

Said cutting unit comprises a rotary cutting blade, mounted in such a way that it is coaxial with said impeller and rotates together with it, being conveniently mounted on the same shaft as said impeller, and a cutting plate rigidly mounted on the pump body, and wherein said rotary cutting blade and said non-rotating cutting plate cooperate with each other and define the cutting interface.

Said cutting plate, mounted between said impeller and said cutting blade, comprises a centre opening at the level of the impeller shaft and is rigidly constrained to the pump body, for example bolted onto it.

Said impeller and said cutting blade are both constrained to said shaft so that they rotate integrally with it, for example and conveniently through a mechanical connection with at least one fixing tab or key.

In order to prevent the cutting blade from coming off the shaft and to lock it in position with respect to the cutting plate, the new pump is provided with at least one self-locking nut suited to be screwed to the end of the shaft that projects from the cutting blade upstream of the latter with respect to the liquid suction direction. According to the invention, in order to regulate the cutting efficiency, said cutting plate can be translated axially, so that it is possible to vary its distance from said cutting blade, while on the other hand the position of the latter with respect to the impeller cannot be changed.

The characteristics of the new cutter pump are highlighted in greater detail in the following description, making reference to the drawings which are attached hereto by way of non-limiting example.

Figure 1 shows a longitudinal axial section view of the pump (10) when it is completely assembled.

Figure 2 shows part of a further longitudinal axial section view, different from the previous one, of the pump (10) when it is completely assembled.

Figure 3 shows a view of the suction side of the pump (10) when it is completely assembled.

The new cutter pump (10) comprises a pump body (14) provided with at least one housing (11) with an impeller (20) rotating therein.

Said impeller (20) is mounted on a driving shaft (30) and rotates around the axis (X) of the shaft (30) inside said housing (11) created in said pump body (14). In particular, said impeller (21) comprises a through axial opening (21) suitable for the insertion of said shaft (30).

Said housing (11) comprises a suction intake (12) which is substantially axial with respect to the impeller (20) and an outlet (13) intended to discharge the fluid in a substantially radial direction.

The transported liquid thus flows in axial direction during the suction phase and in radial direction during the delivery phase.

A cutting unit (40) is mounted coaxially with said impeller (30), upstream of said suction intake (12), so that the liquid to be transported flows through it before reaching said housing (11).

Said cutting unit (40) comprises a rotary cutting blade (50) mounted on said driving shaft (30) in such a way that it is coaxial with said impeller (20) and rotates together with it. Said cutting blade (50) comprises a through axial opening (51) suitable for the insertion of the driving shaft (30) and one or more substantially radial cutting elements (52).

Said cutting unit (40) comprises also a cutting plate (60) mounted between said impeller (20) and said cutting blade (50) and rigidly constrained to the pump body (14), for example bolted onto the latter (62).

Said cutting plate (60) comprises a centre opening (61) and the driving shaft (30) passes through the latter.

Said cutting blade (50) rotates with respect to said cutting plate (60), and said cutting blade (50) and said cutting plate (60) cooperate with each other defining the cutting interface (T) through which the liquid flows and in which the solid elements transported by the liquid are cut.

Said impeller (20) and said cutting blade (50) are constrained to said shaft (30) in such a way that they rotate integrally with it and with each other, for example and conveniently through the same fixing tab or key (32). In particular, said impeller (20) and said cutting blade (50) are mechanically connected to each other and to said shaft (30) through a single tab (32) inserted between said shaft (30) and said axial non-threaded openings (21, 51) of said impeller (20) and of said cutting blade (50).

In practice, said impeller (20), said cutting blade (50) and said shaft (30) make up a single body.

The end (31) of said driving shaft (30) that projects through said opening (51) of said cutting blade (50) is threaded externally, so that a nut (70), conveniently of the self-locking type with the respective washer (71), can be screwed thereon in such a way as to lock the cutting blade (50) and the impeller (20) on the shaft (30).

In particular, said cutting blade (50) and said impeller (20) are maintained in contact with and abutting against each other through said opening (61) created in said cutting plate (60), thanks to the tightening force of said nut (70).

In the preferred solution, said impeller (20) comprises an annular portion (22) in which said shaft (30) is inserted and which projects from the impeller (20) towards said cutting blade (50), and wherein said annular portion (22) of the impeller (20) is maintained in contact with said cutting blade (50).

Said cutting blade (50) conveniently comprises an annular portion (53) in which said shaft (30) is inserted and which projects from said cutting blade (50) towards said impeller (20), and wherein said annular portion (53) of the cutting blade (50) is maintained in contact with said annular portion (22) of the impeller (20).

With reference to Figures 2 and 3, in a possible embodiment of the invention said cutting plate (60) can be moved axially in such a way as to adjust its distance from said cutting blade (50), which instead remains constrained to said shaft (30) and to said impeller (20) in a fixed manner.

In particular, said pump body (14) comprises at least one fixed portion (16) and at least one adjusting portion (15) to which said cutting plate (60) is rigidly constrained, for example through fixing means (62).

Said adjusting portion (15) can be rigidly constrained to said fixed portion (16) through fixing means (151), wherein adjustable spacer elements are positioned between said fixed portion (16) and said adjusting portion (15), for example one or more threaded dowels (17) which are distributed homogeneously and engaged in correspondingly threaded seats (152) created in said adjusting portion (15).

Said adjustable spacer elements or dowels (17), which abut on a point (161) against said fixed portion (16), are therefore screwed to a larger or smaller extent into said adjusting portion (15), thus determining the position of said adjusting portion (15) itself with respect to said fixed portion (16) of the pump body (14), and consequently determining also the position of said cutting plate (60) with respect to said cutting blade (50), that is, determining the cutting efficiency.

Therefore, with reference to the above description and the attached drawings, the following claims are expressed.