CENTRIFUGAL ELECTRIC PUMP AND MOTOR CASING FOR SUCH PUMP

Abstract

A centrifugal electric pump includes a motor casing, containing in turn, an electric motor with a transmission shaft and a hydraulic part. The transmission shaft is connected to at least one impeller present disposed in the hydraulic part. The motor casing is provided internally with a housing in which the electric motor is accommodated. An external surface of the housing defines a cooling surface adapted to be flowed over by pumping liquid that arrives from the hydraulic part. The cooling surface is provided with a covering that is resistant to oxidation. The covering is constituted by a hydraulically isolating sheath, which is contoured to affect the cooling surface.

Claims

1. A centrifugal electric pump comprising a motor casing, containing an electric motor with a transmission shaft, and a hydraulic part, the transmission shaft being connected to at least one impeller disposed in said hydraulic part, said motor casing being provided internally with a housing in which said electric motor is accommodated, an external surface of said housing defining a cooling surface, adapted to be flowed over by pumping liquid that arrives from said hydraulic part, said cooling surface being provided with a covering that is resistant to oxidation, wherein said covering is constituted by a hydraulically isolating sheath contoured to affect said cooling surface.

2. The electric pump according to claim 1, wherein said sheath is made of plastic material.

3. The electric pump according to claim 1, wherein said sheath is made of elastomeric material.

4. The electric pump according to claim 1, wherein said sheath is inserted into the motor casing in a removable manner.

5. The electric pump according to claim 1, wherein said sheath is glued inside the motor casing.

6. A motor casing, containing an electric motor, said motor casing having a housing disposed therein in which said electric motor is accommodated, the external surface of said housing defining a cooling surface adapted to be flowed over by pumping liquid, said cooling surface being provided with a covering that is resistant to oxidation, wherein said covering is constituted by a hydraulically isolating sheath contoured to affect said cooling surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Further characteristics and advantages of the disclosure will become better apparent from the detailed description that follows of a preferred, but not exclusive, embodiment of the centrifugal electric pump according to the disclosure, which is illustrated for the purposes of non-limiting example in the accompanying drawings wherein:

[0028] FIG. 1 is a cross-sectional side view of a centrifugal electric pump according to the disclosure;

[0029] FIG. 2 is a cross-sectional, partially exploded plan view of the electric pump according to the disclosure;

[0030] FIG. 3 is a cutaway perspective view of a pump body with covering, partially assembled; and

[0031] FIG. 4 is a cutaway perspective view of the pump body of FIG. 3 with covering, assembled.

DETAILED DESCRIPTION OF THE DRAWINGS

[0032] With reference to the figures, a centrifugal electric pump according to the disclosure is generally designated with the reference numeral 10.

[0033] The centrifugal electric pump 10 comprises a motor casing 11, which in turn contains an electric motor 12 with a transmission shaft 15, and a hydraulic part 13.

[0034] The transmission shaft 15 is connected to an impeller 14 which is in the hydraulic part 13.

[0035] The motor casing 11 is provided internally with a housing 16 inside which the electric motor 12 is arranged.

[0036] The external surface of the housing 16 provides a cooling surface 17, which is adapted to be flowed over by the pumping liquid originating from the hydraulic part 13.

[0037] The cooling surface 17 is provided with a covering that is resistant to oxidation.

[0038] The covering is constituted by a hydraulically isolating sheath 18, which is contoured to affect the cooling surface 17.

[0039] The sheath 18 is made of plastic material, and therefore can be provided by molding, for example by injection molding or by compression molding.

[0040] The sheath 18 is made of elastomeric material, and preferably of rubber.

[0041] Elastomeric rubber has good mechanical properties, since it can have a good value of load on breakage, of resistance to permanent deformation, and of elastic recovery, and a good resistance to fatigue, to tearing and to wear, plus it is non-toxic and therefore lends itself well to be flowed over by water without releasing pollutants.

[0042] The motor casing 11 is made of aluminum.

[0043] The motor casing 11 can be provided by casting or, preferably, by high-pressure die casting of aluminum; subsequently the motor casing 11 is mechanically machined.

[0044] The motor casing 11 comprises an outer enclosure 19 and the internal housing 16, which are integrated in a single piece of aluminum

[0045] Between the housing 16 and the inner surface of the housing 19, an interspace 20 is defined for the circulation of the pumped cooling liquid.

[0046] The hydraulically isolating sheath 18, contoured to affect the cooling surface 17, is therefore contoured to cover both the housing 16 and the inner surface of the housing 19 which cooperates to define the interspace 20, as can clearly be seen in FIGS. 2, 3 and 4, thus protecting both the housing 16 and the enclosure 19.

[0047] It can clearly be seen in FIG. 3 that the sheath 18 is a separate component, made by molding and then assembled with the motor casing 11.

[0048] The sheath 18 has a perimetric edge 21 with a fold 22 that is designed to be locked by pinching between the join flanges 23 and 24 respectively of the motor casing 11 and of the hydraulic part 13.

[0049] In a first variation of embodiment of the disclosure, the sheath 18 is inserted into the motor casing 11 in a removable manner, and is therefore free to be removed if the necessity arises.

[0050] In a second variation of embodiment of the disclosure, the sheath 18 is inserted into the motor casing 11 and is glued therein.

[0051] The sheath 18, if not glued, in addition to being rapidly assemblable, is also equally rapidly removable for substitution or for the separate disposal of the components of the electric pump at end of life.

[0052] The centrifugal electric pump 10 according to the disclosure therefore has the electric motor 12, synchronous with permanent magnets or traditional asynchronous, cooled by the pumped liquid.

[0053] Such an electric pump 10 comprises the above mentioned components which contribute to achieving the principal aim, i.e. the saving of energy with respect to conventional traditional pumps.

[0054] The pump 10 also brings other important advantages, such as a reduction of noise and contained encumbrances with respect to similar electric pumps on the market today.

[0055] In particular, the reduction of noise is due to the fact that there is no rear fan used to cool the motor, given that the motor is particularly efficient and cooled by the pumped liquid.

[0056] In particular the electric motor 12 is cooled by the pumped liquid (in this case water) by virtue of the removal of heat achieved through the cooling surface 17 and by virtue of the overlying sheath 18 and the rear fan used to cool the motor has been eliminated. The motor casing is made of aluminum lined with rubber in order to protect it from oxidation in the parts in contact with water.

[0057] The disclosure also relates to a motor casing 11 as described above, containing an electric motor 12; the motor casing 11 is provided internally with a housing 16 in which the electric motor 12 is accommodated, the external surface of the housing 16 defining a cooling surface 17 which is adapted to be flowed over by pumping liquid originating from a hydraulic part 13 of an electric pump of which the motor casing 11 is part.

[0058] The cooling surface 17 is provided with a covering that is resistant to oxidation.

[0059] The motor casing 11 is characterized in that the covering is constituted by a hydraulically isolating sheath 18, which is contoured to affect the cooling surface 17, as described above.

[0060] In practice it has been found that the disclosure fully achieves the intended aim and objects.

[0061] In particular, with the disclosure a centrifugal electric pump has been devised that is capable of ensuring the right level of cooling of the motor in the absence of a cooling fan, and which can be produced at low cost.

[0062] Furthermore, with the disclosure an electric pump has been devised the aluminum motor casing of which is covered simply and equally effectively in terms of isolation from water and therefore of protection from oxidation.

[0063] What is more, with the disclosure an electric pump has been devised with a motor casing made of aluminum, therefore lighter than conventional casings, thus ensuring an overall greater lightness for the entire centrifugal pump.

[0064] What is more, with the disclosure an electric pump has been provided in which a good control is ensured of the geometric and dimensional tolerances of the aluminum components in the finished product.

[0065] The disclosure, thus conceived, is susceptible of numerous modifications and variations. Moreover, all the details may be substituted by other, technically equivalent elements.

[0066] In practice the components and the materials employed, provided they are compatible with the specific use, and the contingent dimensions and shapes, may be any according to requirements and to the state of the art.