Field of the invention

The present invention relates to a pump assembly for a household appliance, in particular a dishwasher. The pump assembly allows both heating and pumping liquid.

Background art

Many household appliances use pumps to generate flows of liquid. Dishwashers and washing machines are examples of household appliances which comprise one or more pumps for pumping a liquid, typically water.

In general, the pumps used comprise a housing in which an impeller is arranged, and the motor which actuates the impeller is arranged outside the housing. Thereby, the motor does not come into contact with the liquid.

Centrifugal pumps are often used in washing machines, wherein the inlet of the liquid is substantially perpendicular to the outlet of the liquid.

In the applications in which it is also required to heat the liquid, in dishwashers for example, the pump also comprises heating means.

One of the limits of the current pumps for household appliances, in particular when they are provided with heating means, is the size thereof, which would be advantageous to reduce. In particular, it would be advantageous to be able to reduce the diameter of the pumps for household appliances.

The undesired vibrations generated by the motor which actuates the impeller are another disadvantage of the current pumps for household appliances.

Therefore, the need is felt to overcome the limits of the background art.

Summary of the invention

It is an object of the present invention to make a pump assembly for a household appliance, in particular a dishwasher, which allows both the function of heating the liquid and pumping the liquid to be absolved, and which is also compact.

It is another object of the present invention to make a pump assembly which allows the liquid to be heated, is compact and which produces less vibrations with respect to the background art. The present invention achieves at least one of such objects and other objects which will be apparent in light of the present description, by means of a pump assembly for a household appliance, the pump assembly comprising:

a conduit for the passage of a liquid, comprising a casing which extends between an inlet for the liquid and an outlet for the liquid, and which defines an inner passageway for the liquid between the inlet and the outlet;

an impeller arranged in the inner passageway for the liquid;

a motor arranged in the inner passageway for the liquid, connected to the impeller, adapted to rotate the impeller; and

at least one heating element, adapted to heat the liquid flowing into the conduit. The motor in particular is arranged so as to be lapped, i.e. wetted, by the liquid passing through the conduit.

The motor in particular is arranged between said inlet for the liquid and said outlet for the liquid.

According to an aspect, the invention also comprises a household appliance, in particular a dishwasher, comprising at least one pump assembly, in particular at least one pump assembly according to any one of claims 1 to 1 1.

The pump assembly advantageously allows the liquid to be heated, has compact sizes, in particular has a compact diameter, and generates less undesired vibrations. The reduction of the undesired vibrations in particular is obtained by the arrangement of the motor inside the conduit for the liquid, in particular inside the inner passageway.

With particular reference to dishwashers, the compact sizes of the pump assembly allow larger washing compartments to be made and to optimize the distribution of the components, in particular close to the dishwasher sump.

The pump assembly advantageously may be made at an affordable cost.

The pump assembly advantageously allows the volume of liquid required to absolve the liquid pumping function to be reduced, and therefore the overall energy consumption to be reduced.

Furthermore, when said at least one heating element is arranged outside the conduit, it may be easily repaired.

The pump assembly, or household appliance, advantageously may also comprise a flow diverter, or flow distributor, for directing the liquid into one or more conduits which feed, for example, one or more spray arms.

Furthermore, the pump assembly advantageously may be fastened to the household appliance by means of one or more sleeves, preferably made of rubber, without the need for further fastening means.

For example, one sleeve may be provided, which fastens the conduit, close to the inlet, to the sump of the household appliance. Preferably, another sleeve is provided, preferably made of rubber, which fastens the conduit, close to the outlet, to the diverter or to a conduit of the household appliance, for example a conduit which feeds one or more spray arms.

Further features and advantages of the invention will be more apparent in light of the detailed description of exemplary, but not exclusive, embodiments.

The dependent claims describe particular embodiments of the invention.

Brief description of the Figures

Reference is made in the description of the invention to the accompanying drawings, which are provided by way of explanation and not by way of limitation, wherein:

Figure 1 diagrammatically shows a pump assembly according to an embodiment of the invention;

Figure 2 diagrammatically shows a pump assembly according to another embodiment of the invention;

Figure 3 diagrammatically shows certain components of a pump assembly in accordance with the invention;

Figure 4 diagrammatically shows an inner view of certain components of Figure 3; Figure 5 diagrammatically shows a view of the inside of a household appliance in accordance with the invention.

The same elements or components have the same reference numeral.

Description of example embodiments of the invention

With reference to the Figures, a pump assembly 100, 100’ for a household appliance 200 is described. The household appliance 200 is, for example a dishwasher (partially shown in Figure 5). Alternatively, the household appliance may be, for example another type of washing household appliance, such as a washing machine, or it may be a cooling household appliance or any other household appliance envisaging the use of one or more pumps for a liquid which is also to be heated.

The pump assembly 100, 100’ substantially is an assembly of components which serves to pump and heat a liquid.

The liquid preferably is water or in any case a liquid comprising water, such as an aqueous mixture.

The pump assembly 100, 100’ comprises:

a conduit 1 for the passage of a liquid, comprising a casing 1 1 which extends between an inlet 12 for the liquid and an outlet 13 for the liquid, and which defines an inner passageway 14, or inner passage channel, for the liquid between inlet 12 and outlet 13;

an impeller 2 arranged in the inner passageway 14;

a motor 3 arranged in the inner passageway 14, connected to impeller 2, adapted to rotate impeller 2; and

at least one heating element 4, 4’, adapted to heat the liquid flowing into conduit 1. Motor 3 in particular is arranged between said inlet 12 for the liquid and said outlet 13 for the liquid.

Conduit 1 may, for example be a tube. Conduit 1 may, for example, be rectilinear or curvilinear and may optionally comprise one or more elbows. The inner diameter of conduit 1 preferably is less than 90 mm, for example comprised between 20 and 60 mm. The inner diameter of conduit 1 preferably is less than or equal to 60 mm, for example comprised between 30 and 50 mm.

The casing 1 1 of conduit 1 may be made, for example of metal or plastic, and preferably is rigid.

Casing 1 1 comprises or consists of a wall having an outer surface and an inner surface, which are opposite to each other. The inner surface of casing 11 delimits the inner passageway 14 of conduit 1.

The pump assembly 100, 100’ advantageously comprises at least one heating element 4, 4’ adapted to heat the liquid flowing into conduit 1.

Preferably, only one heating element 4, 4’ is provided, although a plurality of heating elements 4, 4’ may be provided. The heating element 4, 4’ preferably is an electric heating element, i.e. an element that may generate heat when it is crossed by an electric current, in particular due to the Joule effect. In other words, the heating element preferably is an electric resistor.

The heating element 4, 4’ preferably is fixed to the outer surface of the casing 11 of conduit 1. Therefore, the heating element 4, 4’ is arranged externally to the inner passageway 14.

The heating element 4, 4’ may heat the wall of conduit 1 , casing 1 1 in particular, which in turn may heat the liquid flowing inside the conduit 1.

Alternatively or additionally, the heating element may be arranged inside the conduit 1 , in particular in the inner passageway 14.

The heating element 4, 4’ preferably is arranged between inlet 12 and outlet 13, in particular at the inner passageway 14.

The heating element 4, 4’ preferably is proximal to the impeller 2 and distal from the motor 3.

The heating element 4, 4’ preferably is at the impeller 2, for example it extends around the impeller 2, in particular partially or completely around the impeller 2. Preferably, the heating element 4, 4’ completely or partially extends around the casing 1 1 of conduit 1 , in particular around the inner passageway 14.

With particular reference to Figure 1 , the heating element 4, for example, is a sheathed resistor 4. The outer casing, or sheathing, of the sheathed resistor 4 is made of metal, preferably aluminum or aluminum alloy.

The outer casing of the sheathed resistor 4 preferably is welded or brazed to the casing 1 1 of conduit 1.

The sheathed resistor 4 preferably comprises a plurality of coils 41 which extend around the conduit 1.

The coils 41 preferably are adjacent to one another.

Each coil 41 has a portion which is proximal to the outer surface of casing 1 1 and a portion which is distal from said outer surface, and the proximal portion preferably has a greater surface with respect to the distal portion.

For example, the coils 41 preferably have a substantially trapezoid-shaped section, with the long base proximal to conduit 1 and the short base distal from conduit 1. This particular shape allows the heat exchange and energy efficiency to be optimized.

With particular reference to Figure 2, the heating element 4’ is, for example a resistor of the thick film resistor or of the thin film resistor type. These types of resistors are in themselves known to a person skilled in the art.

This type of resistors in particular comprises an electrically conductive layer, for example a metal layer. The thickness of the metal layer preferably is from about 0.1 pm to about 100 pm. The electrically conductive layer preferably is fixed to one or more layers of electrically insulating material.

The thickness of the conductive layer of a thin film resistor preferably is less than about 10 pm.

A thin film resistor may be made, for example by means of Physical Vapour Deposition (PVD) or Chemical Vapour Deposition (CVD).

The thickness of the conductive layer of a thick film resistor preferably is comprised between about 10 pm and about 80 pm.

A thick film resistor may be made, for example by means of screen printing.

In the embodiment shown in Figure 2, the thick film resistor or the thin film resistor is shaped as a sheet adhered to the outer surface of conduit 1. The thick film resistor or thin film resistor preferably is shaped according to the shape of the outer surface of conduit 1. For example, when the outer surface of conduit 1 is cylindrical, also the thick film resistor or the thin film resistor defines a cylindrical surface.

Alternatively to the types of resistors described previously, or alternatively to the deposition techniques mentioned previously, the heating element may be a resistor made by means of plasma spraying.

Preferably, but not exclusively, the inlet 12, or the inlet opening, and the outlet 13, or the outlet opening, are opposite to each other.

Preferably, but not exclusively, the inlet 12 and the outlet 13 extend around a same axis X, which preferably is the longitudinal axis of conduit 1. In particular, it is preferable that the inlet 12 and the outlet 13 are coaxial to each other.

Furthermore, the rotation axis of impeller 2 preferably is said axis X or an axis which substantially is parallel to said axis X. Therefore, preferably the inlet direction F of the liquid, through the inlet 12, substantially is equal to the outlet direction F of the liquid through the outlet 13, as diagrammatically shown in Figures 1 and 2.

Impeller 2 is adapted to generate a flow of liquid which, passing through the inner passageway 14, goes from the inlet 12 to the outlet 13.

Impeller 2 preferably is proximal to the inlet and motor 3 is distal from the inlet 12, i.e. proximal to the outlet 13.

Motor 3 preferably is fastened to conduit 1. For this purpose, there are preferably provided one or more supports which fasten the motor 3 to the conduit 1 , in particular to the wall of casing 1 1.

Preferably, the motor 3 is arranged completely inside the conduit 1 , in particular completely inside the inner passageway 14. Motor 3 preferably is arranged so as to be lapped, i.e. wetted, by the liquid passing through conduit 1 , in particular so as to be completely immersed in the liquid. In other words, the liquid preferably may flow about and/or past the motor 3.

Motor 3 is hermetically sealed or in any case sealed so that the liquid cannot enter the inner part of motor 3. For this purpose, for example the motor preferably is provided with an outer housing. In other words, motor 3 is provided with an outer housing which prevents the inlet of the liquid.

Preferably, the motor 3, in particular the outer housing, is spaced apart from the wall delimiting the inner passageway 14.

Motor 3 preferably is an electric motor. Motor 3 may, for example, be a DC motor, preferably a low voltage motor, for example comprised between 12 and 230 V. Alternatively, the motor may be of the AC type.

Preferably, only one motor 3 is provided and, preferably, only one impeller 2 is provided.

Motor 3 preferably is connected to the impeller 2 by means of a shaft 23, which may transmit the rotation motion to the impeller 2.

Shaft 23, for example, may pass through the outer housing of motor 3 and sealing means for preventing the inlet of liquid into the motor may be provided. The sealing means, for example, may comprise a gasket, for example an O-ring, arranged between shaft 23 and the outer housing of motor 3. An electric cable 31 provided with an insulating sheath is provided to electrically feed motor 3. The electric cable 31 may pass through the outer housing of motor 3 and sealing means may be provided, for example a gasket, which are arranged between the electric cable 31 and the housing of motor 3 to prevent the inlet of the liquid into motor 3. Furthermore, the electric cable 31 may pass through the wall of conduit 1 and sealing means may be provided, for example a gasket, which are arranged between the wall and the electric cable 31 to prevent the liquid from coming out of conduit 1.

With particular reference to Figures 3 and 4, the pump assembly 100, 100’ preferably comprises a flow diverter 5, or flow distributor, arranged downstream of the outlet 13 of conduit 1.

Diverter 5 preferably comprises a movable element 51 provided with two or more openings, for example with two openings 51 1 , 512, for the passage of the liquid. The openings 51 1 , 512 preferably are circular. Outlet 13 preferably faces the movable element 51.

The movable element 51 preferably is shaped as a plate, preferably a circular plate. The two largest surfaces of the plate, which are opposite to each other, preferably are transversal, preferably orthogonal, to said axis X.

Diverter 5 in particular serves to channel the flow of liquid coming out of outlet 13 into two or more conduits, for example two conduits 203, 204, which preferably are part of the household appliance 200.

Diverter 5 preferably comprises two conduits 503, 504 adapted to be connected to the two conduits 203, 204, respectively.

The conduits 503, 504 are separated from each other. Reference numeral 58 in Figure 4 indicates a partition septum between the two conduits 503, 504.

Conduit 503 has an inlet opening 541 and conduit 504 has an inlet opening 542. The openings 541 , 542 preferably are made in a wall 54 which is fixed in position. The inlet opening 512 of the movable element 51 is shown with dashed line in Figure 4, it being covered by wall 54.

Wall 54 is part of the structure 55 of the diverter 5. Structure 55 preferably comprises a coupling portion 56, for example an annular coupling portion, to which conduit 1 is constrained. The inlet openings 541 , 542 preferably are circular. Preferably, the outlet 503a of conduit 503 and the outlet 504a of conduit 504 are substantially orthogonal to axis X, or in other words they extend about a respective axis which is orthogonal to axis X. This configuration is particularly advantageous in particular when the inlet 12 and the outlet 13 of conduit 1 are opposite to each other, for example extend about the same axis X.

The movable element 51 preferably is arranged between the outlet 13 of conduit 1 and the conduits 503, 504, for example between outlet 13 and wall 54. In other words, the movable element 51 preferably is arranged between the coupling portion 56 and the wall 54.

The movable element 51 may in particular have two positions according to the position of the openings 51 1 , 512.

In a first position of the movable element 51 , shown in Figure 4, diverter 5 allows channeling the flow of liquid into conduit 503 and prevents the passage of liquid into conduct 504. Indeed, opening 51 1 is substantially aligned, for example coaxial, with the inlet opening 541 of conduit 503. Therefore, the liquid may pass in conduit 503 through the openings 511 and 541.

Furthermore, the other opening 512 of the movable element 51 is in a different position with respect to the inlet opening 542 of conduit 504, whereby the liquid may not enter in the conduit 504. Indeed, opening 512 is obstructed by wall 54.

In a second position (not shown) of the movable element 51 , the opening 51 1 is aligned, for example coaxial, with opening 542 of conduit 504, and the opening 512 is aligned, for example coaxial, with the opening 541 of conduit 503. Therefore, the liquid may enter both in conduit 503 and in conduit 504. The movable element 51 preferably is adapted to rotate, preferably about axis X, or about an axis parallel to axis X.

A motor 53, preferably an electric motor, is provided in order to move the movable element 51 , for example to actuate the rotation of the movable element 51.

A shaft 52 connects motor 53 to the movable element 51 and may transmit the rotation motion imparted by motor 53 to the movable element 51.

Motor 53 preferably is external to the conduits 1 1 , 503 and 504. Motor 4 preferably is fastened externally to the structure 55. Shaft 52 may, for example cross a wall delimiting conduit 503, as shown in Figure 3. Sealing means which prevent the liquid from coming out of the wall crossed by shaft 52 are preferably provided. Shaft 52 may also cross wall 54.

It should be clear that a diverter having different features, possibly in itself known, may also be used alternatively to diverter 5.

With particular reference to Figure 5, part of a household appliance 200 comprising a pump assembly 100 or 100’ is diagrammatically shown.

The household appliance 200, for example, is a dishwasher.

In particular, the household appliance 200 comprises a washing compartment 201 and a sump 202. Sump 202 may receive liquid from the washing compartment 201 and preferably is arranged below the washing compartment 201.

The household appliance 200 also comprises sprayers for dispensing liquid into the washing tank 201. The sprayers are, for example, spray arms, preferably rotating spray arms. A lower spray arm 205, an intermediate spray arm 206 and an upper spray arm 207 are provided, for example. The lower spray arm 205 is proximal to the sump 202.

In the example shown, a pump assembly 100 is provided, arranged downstream of sump 201 and upstream of the conduits 203, 204. Conduit 203 is adapted to feed the lower spray arm 205 and conduit 204 is adapted to feed the intermediate spray arm 206 and the upper spray arm 207.

The pump assembly 100 is connected to sump 202 to draw the liquid contained in sump 202 and direct it towards the washing compartment 201.

In particular, the impeller 2 is adapted to generate a flow of liquid from sump 202 towards the conduits 203, 204.

Preferably, there is provided the diverter 5, which allows channeling the flow of liquid coming out of outlet 13 into conduit 203 and/or into conduit 204, according to the position of the movable element 51 , as explained previously, in particular according to the relative position between the movable element 51 and wall 54. The conduit 503 of diverter 5 is connected to conduit 203 and the conduit 504 of diverter 5 is connected to conduit 204.

Preferably, conduit 1 , close to the inlet 12, is constrained to sump 202, or to a portion of a conduit connected to sump 202, by means of a sleeve, preferably a rubber sleeve. Preferably, conduit 1 , close to outlet 13, is constrained to structure 55 by means of a sleeve, preferably a rubber sleeve. Structure 55 may be part of the household appliance 200 or of the diverter 5.

Preferably, further fastening means for constraining the pump assembly 100, 100’ to the other parts of the household appliance 200 are not provided.

Although a household appliance is referred to in the present description, the invention also relates to apparatuses for industrial or professional uses.