The present application relates to a double delivery centrifugal pump for an electric appliance, specifically a dishwasher and/or a glasswasher of the professional/commercial use type.
It is known that dishwashers, in particular those for professional use (for bars, restaurants, communities, etc.) include a washing chamber provided with upper and lower washing means (e.g., usually upper and lower washing arms) and delimited downwards by a collection sump of the service fluid (washing water), also referred to as cleaning liquid, which is, at least partially, filtered and recycled by a feeding pump, which draws the service fluid from the sump and sends it to the washing arms.
Therefore, the flow of service fluid fed by the pump needs to be split into two separate flows, to be indeed separately fed to both the upper and lower washing arms. Furthermore, in dishwashers of different types, the flow rate of service fluid to be fed to the upper and lower washing arms may be different; in particular, dishwashers for professional use may be specialised machines, e.g. machines for washing plates in which the greater flow of water is to be directed to the upper washing arm, and glasswashers in which the greater flow of water is to be directed to the lower washing arm (e.g., due to the fact that glasses are almost always placed in the washing cavity in an inverted manner). As used herein the term “warewasher” collectively refers to both dishwasher and glasswashers.
In order to split and adjust the flow of water, possibly with the addition of detergents (service fluid), deviating means are used in the form of valves or simply in T-fittings provided with calibrated bottleneck, which intercept the flow downstream of the pump delivery pipe in relation to the flow rates to be obtained. From EP1004266, a feeding pump of a service fluid to the upper and lower washing arms of a dishwasher is however known, which displays two delivery pipes obtained on the same pump body, in diametrically opposite position. The need for deviating means is thus avoided because the same impeller of the pump simultaneously provides the two separated flows.
The pump known from EP1004266 however does not solve the problem of being able to direct different flow rates to the upper and lower washing arms of the dishwasher.
It would be desirable to overcome in a simple way the drawbacks of the known art by providing a feeding pump of a service fluid to the washing arms of an electric household appliance, specifically a dishwasher, which does not require deviating means for feeding separate, different flows to the washing arms of the electric household appliance and, above all, can be used without any changes both in electric household appliances which require the feeding of the greater flow rate of service fluid to the upper arm, such as dishwashers, and in electric household appliances which require the feeding of the greater flow rate of service fluid to the lower arm, such as glasswashers.
It would also be desirable to provide a pump of the aforesaid type which is at the same time reliable, compact, relatively cost-effective, simple and easy to be assembled and disassembled, and above all ensures a good sealing to the service fluid and finally facilitates maintenance interventions.
In one aspect, a pump includes a pump body fluid-sealingly housing a centrifugal impeller and provided with a first delivery pipe and a second delivery pipe located on the pump body in diametrically opposite, tangential positions with respect to a rotation axis of the impeller, and with first fastening means to a casing of the electric household appliance; the first and second delivery pipes, however, display passage sections which are different from one another and the pump also comprises, in combination with this feature, second fastening means to the casing of the electric household appliance.
The first and second fastening means may be specifically designed to be selectively used to assemble the pump body, either with the first delivery pipe arranged above and the second delivery pipe arranged below the rotation axis of the impeller or vice versa, so that the pump, depending on whether the first or the second fastening means are selected, may be used for an electric household appliance consisting either of a dishwasher or a glasswasher.
The pump body includes a hydraulic conveying scroll defined by a cup-shaped half-shell, a closing lid of a mouthpiece of the scroll, which may be housed in a seat defined by an annular collar of the scroll and axially carrying a suction pipe, the lid resting in use in axial abutment against an annular bottom wall of the annular collar, with the interposition of a sealing ring, and a threaded locking ring coupled with a threaded segment of the collar to axially and uniformly press in use the lid against the bottom wall along a peripheral edge of the lid itself.
In this manner, the same pump may be used, without any changes thereto, but by simply mounting it in an inverted position each time, on different and differently specialised dishwashers, for directing different flow rates of service fluid (water and possibly detergent) to different washing arms of the electric household appliance, with consequent great scale economies.
Furthermore, the pump may be easily and entirely formed by moulding a synthetic plastic material, with consequent reduction of costs and weight, without affecting the sealing reliability in use of the service fluid which is pumped; indeed, the specific composition and structure of the pump body allows to ensure an optimal and safe sealing between lid and scroll, by means of the screwed closing of the lid directly onto the scroll, obtained by means of the threaded locking ring/collar coupling, instead of using a flanged-type closure with several fastening screws, commonly used for dishwasher pumps.
Each first and second delivery pipe may be laterally provided perpendicularly to a side wall thereof, with a branched discharge conduit preferably obtained integrally in one piece with the pump body, externally on the same.
A first discharge conduit is closed in use by a plug and a second discharge conduit is instead connected in use to the sump of the electrical household appliance, from which the pump is intended to draw the service fluid in use.
In this manner, a complete emptying of the scroll is ensured when the pump is stopped and the sump is emptied, which greatly simplifies, along with the general structure of the pump body, the cleaning interventions, by improving the hygienic features of the dishwasher during the non-use periods, however without substantially penalising the step of pumping.
An electric household appliance, in particular a dishwasher or glasswasher for professional use, equipped with the aforesaid pump is provided.
Further aspects will be apparent from the following description of an embodiment thereof, provided only by way of non-limitative example and with reference to the accompanying drawings, in which:
a and 3b diagrammatically show the pump in
With reference to
The pump 1 includes a pump body 4 fluid-sealingly housing a centrifugal impeller 5 (of known type) and provided with a first delivery pipe 6 and a second delivery pipe 7 tangentially oriented on the pump body 4 in diametrically opposite positions with respect to a rotation axis A of the impeller 5. First fastening means 9 is provide for securing the pump to a casing 10 (e.g., housing or frame) of the electric appliance 3. The first delivery pipe 6 and the second delivery pipe 7 have passage sections (e.g., flow passages) which are different from one another. In particular the pipe 6 has a diameter smaller than the pipe 7 and, therefore, provides a smaller flow passage (i.e., a smaller cross-sectional flow area). Both the pipes tangentially draw from the inside of the pump body 4 and therefore receive the head generated by the impeller 5 in use to the same extent. However, the pipe 7 of larger section displays a lower load loss at the mouthpiece and is thus adapted to convey a higher flow rate Q1 (
The pump 1 also includes second fastening means 12 that may be used for securing the pump to the casing 10 of the appliance 3. The first 9 and second 12 fastening means are designed to be selectively used, to mount the pump body 4, either with the first delivery pipe 6 arranged above and the second delivery pipe 7 arranged below the rotation axis A of the impeller (
The pump body 4 includes a hydraulic conveying scroll 20 of the service fluid taken in by the impeller 5 and defined by a cup-shaped half-shell formed by moulding a synthetic plastic material in a single piece and comprising a side wall 21 and an end wall 23 (
In particular, the impeller 5 is axially and cantileverly supported within the scroll 20 by the bottom wall 23, through an axial passage hole 25 for a drive shaft 26. The bottom wall 23 is further provided, on the outside of the pump body 4, with fastening means 27 (e.g., a screw hole or other known structure) for mounting a driving motor 28.
Furthermore, the first 9 and second 12 fastening means, which may be selectively used, are carried outside the pump body 4, e.g. are carried by the side wall 21, are integrally obtained in one unitary piece with the same and formed by corresponding ears which radially and cantileverly protrude from the pump body 4 with respect to the axis A, in different angular positions, and each provided with at least one through hole.
The electric appliance 3, in both versions 3a and 3b, is provided with first and second known washing means 101 and 102 (
The pump body 4 further includes a closing lid 40 over the mouthpiece 22 of the scroll 20. The closing lid is essentially flange or plate-shaped, which is housed, in use, in a seat 29 defined internally by an annular collar 30 of the scroll 20, axially and cantileverly protruding with respect to the mouthpiece 22.
The lid 40 carries a suction pipe 41 in an axial position, which may be connected in use with the sump 11. The lid rests in use in axial abutment, with the interposition of a sealing ring 43 (o-ring), against an annular bottom wall 35 of the collar 30, which wall peripherally delimits the mouthpiece 22. The bottom wall 35 is preferably provided with an annular groove 36 (
Finally, the pump body 4 includes a threaded locking ring 50 (threaded radially on the outside), that couples with a threaded segment 37 of the collar 30, internally to the same, to axially press in use the lid 40 against the annular bottom wall 35 of the collar 40, at the stroke end, uniformly along the whole peripheral edge 44 of the lid 40 itself, so as to ensure in use the application of a uniform pressure (by the edge 44) on the sealing ring 43.
The threaded locking ring 50 is substantially cup-shaped and is frontally provided, at a bottom annular wall 51 thereof, which is arranged perpendicularly to the threaded segment 37 internally to the collar and facing the lid 40 in use, with a through seat 53 for a safety fastening screw 54 intended to make the locking ring 50 and the lid 40 integral in use.
According to a first possible embodiment (not shown), the lid 40 is simply adapted to cooperate by friction with a stem 55 (
The lid 40 and the scroll 20 may be provided with reciprocally mating relative positioning and angular locking means, respectively in the form of a tooth 49 of the lid 40 located on a side of the lid opposite the pipe 41 and very close to the edge 44, and of a slot 38 and a corresponding angular matching element 38b located on the scroll 20. The slot 38 is located at the mouthpiece 22 and the element 38B is located at a terminal end edge of the collar 30. The slot 38 is defined by the open end part of a radial ridge 39 located inside the scroll 20 and which extends axially from the bottom wall 23 to the mouthpiece 22, and being adapted to receive the tooth 49 in use.
Also the lid 40 and the locking ring 50 are formed by moulding a synthetic plastic resin and therefore the pump body 4 may be entirely formed by synthetic plastic material.
Both the first delivery pipe 6 and the second delivery pipe 7 are each laterally provided, perpendicularly to a side wall thereof, with a branched discharge conduit, indicated by numerals 70 and 71, preferably integrally obtained in one unitary piece with the pump body 4, in this case with the side wall of the collar 30, externally on the same. In use, in the case of the configuration in
In the configuration of
In this manner, a minimum part of the water which is pumped through the pipe 6 or 7 which is arranged each time downwards, i.e. in a position below the axis A, is recirculated in the sump 11, with the advantage that when the pump 1 is stopped, the water which would normally remain trapped inside the scroll 20, may flow out through the piping 77 into the sump 11, thus greatly facilitating the maintenance operations of the pump 1.
Number | Date | Country | Kind |
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TO2007A000347 | May 2007 | IT | national |