Patent Description:
The cover is provided with an electric heating element apt to be wetted by the liquid, and with at least one component for controlling the temperature.

A type of pump cover of a household appliance comprises an electric heater, in particular a sheathed resistor or tubular heater, apt to be wetted by the liquid to be heated.

The temperature of the liquid and of the heating element is controlled by means of electromechanical devices, for example by means of a thermostat and a thermal fuse, such as in the pump cover disclosed in <CIT>.

The electromechanical devices are adequate to ensure the thermal management of the tubular heaters, especially in household appliances, e.g. a dishwasher, equipped with a medium-low level electronics.

Electromechanical devices cannot be associated or are difficult to associate, with more sophisticated electronic control units.

Moreover, electromechanical devices are rather cumbersome.

It would be useful to introduce electronic temperature control components for the tubular heaters because such electronic components could be associated with the other, even more sophisticated, electronic components with which the household appliance is provided. Moreover, electronic temperature control components would also be advantageous because they are smaller in size than the electromechanical devices.

The need is therefore felt for a pump cover of a household appliance provided with a tubular heater apt to be wetted by the liquid to be heated, and provided with one or more electronic temperature control components.

It is an object of the present invention to provide a pump cover provided with an electric heater apt to be wetted by the liquid to be heated in the pump, the cover being provided with one or more NTC thermistors to allow controlling the temperature.

In particular, it is an object of the present invention to avoid the excessive heating of the one or more NTC thermistors so as to avoid the damage thereof.

In particular, it is an object of the invention to allow the use of one or more NTC thermistors which are of the compact and affordable type.

It is another object of the invention to allow the disassembly of the one or more NTC thermistors so as to allow the replacement thereof if needed.

The present invention achieves at least one of such objects and other objects which will become apparent in light of the present description, by means of a cover for a pump for a liquid for a household appliance, in particular for a dishwasher or a washing machine;.

The invention also relates to a pump according to claim <NUM>.

Advantageously, the cover of the invention allows increasing the accuracy and the information which can be obtained by means for detecting the temperature, both during regular operation and during anomalous operation, in a pump cover provided with a heating element apt to be arranged in the body of the pump, i.e. arranged so as to be wetted by the liquid.

Advantageously, the cover of the invention allows using NTC thermistors, avoiding damage due to high temperatures and increasing the accuracy and the information which can be obtained by the NTC thermistors both during regular operation and during anomalous operation.

Advantageously, both NTC thermistors are cooled by the liquid in the pump so they are not damaged by the heat during regular operation.

During regular operation, one NTC thermistor is particularly sensitive to the temperature of the heating element, while the other NTC thermistor is particularly sensitive to the temperature of the liquid, in particular by virtue of the specific positioning thereof and by virtue of the aforesaid notch. The thermal gap, in particular the thermal insulation, provided by the notch allows the difference between the temperature detected by the two NTC thermistors to be increased. Such a difference in temperature provides useful information on the operation both under normal conditions and under anomalous conditions (e.g. dry operation). Note that the notch also allows arranging both NTC thermistors on the same support so as to facilitate the assembly and disassembly operations, in any case allowing one NTC thermistor to be particularly sensitive to the temperature of the heating element and the other NTC thermistor to be particularly sensitive to the temperature of the liquid.

In case of dry operation, both NTC thermistors advantageously are sensitive to the temperature of the heating element by virtue of the specific positioning thereof. Advantageously, the cover of the invention allows the heat profile of the heating element to be controlled, as well as the correct achievement of the temperatures required to execute cleaning cycles to be ensured.

In particular, the cover allows a quick detection of the temperature and a quick intervention of the electronic control unit to which the two or more NTC thermistors may be connected.

Moreover, the two or more NTC thermistors allow increased information concerning the operation and/or malfunctioning of the heating element to be obtained, such as for example, poor heat exchange during circumstances of limescale or dirt accumulation.

As mentioned above, two or more NTC thermistors may be provided.

Preferably, two NTC thermistors are provided, for example only two NTC thermistors.

Advantageously, the two or more NTC thermistors are at said first portion of the wall, which the inner face of which may be wetted by the liquid, in particular so as to avoid the NTC thermistors from being excessively heated by the heating element, and therefore so as to avoid the damage thereof. Indeed, the liquid cools the portion of wall which is wetted.

In particular, the cover is preferably configured so that the two or more NTC thermistors are subject to a temperature which is less than <NUM>, preferably less than <NUM>.

Preferably, the two or more NTC thermistors are in the vicinity, but not at, the second portion of wall, i.e. in the vicinity of, but not at, the stretch of heating element in contact with the inner face.

In other words, the entire first NTC thermistor is at the first portion of wall, and the entire second NTC thermistor is at the first portion of wall.

Preferably, one NTC thermistor is closer to the portion of wall which is in contact with the heating element than the other NTC thermistor.

Advantageously, therefore, one NTC thermistor is more sensitive to the temperature of the liquid, while the other NTC thermistor is more sensitive to the temperature of the heating element.

Advantageously, the two or more NTC thermistors are at, in particular above, the stretch of heating element spaced apart from the inner face and facing the inner face.

Advantageously, the one or more NTC thermistors may thus better perceive the heat generated by the heating element in case of dry operations, in particular when there is no liquid wetting the wall of the cover.

Preferably, the entire first NTC thermistor is at, preferably above, said stretch of heating element, and the entire second NTC thermistor is at, in particular above, said stretch of heating element.

Advantageously, the NTC thermistors are fixed to a support.

Preferably, such a support is arranged partly above the first portion of wall and partly above the second portion of wall.

Preferably, the support is fixed to the wall by means of fastening means which allow the disassembly thereof from the wall, or more generally from the cover, whereby the support and the one or more NTC thermistors may be easily replaced.

The support is made of thermally conductive material, preferably of metal, e.g. aluminum or aluminum alloy.

The support in particular is provided with one or more electrically conductive tracks, in particular metal tracks, to which the one or more NTC thermistors are welded.

A layer of dielectric material is provided between said one or more conductive tracks and the support.

Preferably, an electric connector is fixed to the support and is connected to said one or more conductive tracks.

Preferably, a pre-assembled electronic component comprising the support and the two or more NTC thermistors, the one or more conductive tracks, and preferably also the electric connector, is provided. Alternatively, the electric connector may also be far from the support, in particular from the one or more conductive tracks, and be connected to said one or more conductive tracks by means of a wired connection. Advantageously, the support is provided with one or more notches (or cuts). Each notch in particular is an empty space.

For example, when a notch is provided between two zones of the support, one NTC thermistor is fixed to a first zone and another NTC thermistor is fixed to a second zone.

Advantageously, one NTC thermistor is thus more sensitive to the temperature of the liquid and the other NTC thermistor is more sensitive to the temperature of the heating element because the notch limits the transmission of heat.

The one or more notches allow a difference in temperature to be obtained between the two NTC thermistors. The difference in temperature is information which can be used by an electronic control unit to manage heating the heating element. Preferably, the notch is below the electric connector so that the welds of the legs of the connector, and the structure thereof, compensate for any structural weakening due to the opening of the notch.

The support may be sized according to the operating needs.

By mere way of example, the two NTC thermistors may be connected to an electronic control unit configured with a control logic which takes into consideration the absolute temperature of the two NTC thermistors, the gradient taken on during the operation of the element and the difference in temperature between the two NTC thermistors. Thereby, slow transients during regular operations, fast transients in the absence of heat exchange, and damage to/malfunctioning of the NTC thermistors themselves, may be registered.

When it is specified in the present description that an element is at another element, it means that the two elements are crossed by the same axis which is perpendicular to the aforesaid wall of the cover, in particular perpendicular to the surface of greatest extension of the aforesaid wall, which preferably is substantially flat.

Further features and advantages of the invention will become more apparent in light of the detailed description of non-exclusive embodiments.

The dependent claims describe particular embodiments of the invention.

In the description of the invention, reference is made to the accompanying drawings, which are provided by way of non-limiting example, in which:.

The same elements, or functionally equivalent elements, have the same reference numeral.

With reference to the drawings, example embodiments of a cover <NUM> according to the invention and of a pump <NUM> (<FIG>) comprising cover <NUM>, are described.

Pump <NUM> in particular is a centrifugal pump or recirculation pump.

Cover <NUM> is configured to be fixed to a body <NUM> of pump <NUM>, for example a body which delimits, in particular laterally, a chamber <NUM> for pumping a liquid. Once fixed to body <NUM>, also the cover <NUM> delimits the pumping chamber <NUM>, acting as closing element.

It in particular is a cover <NUM> of a pump <NUM> used in household appliances, such as for example, a dishwasher or a washing machine.

This type of pump is typically, but not exclusively, apt to pump water.

Cover <NUM> comprises a wall <NUM> which has an inner face <NUM>, or lower face, and an outer face <NUM>, or upper face.

The inner face <NUM> is destined to come into contact with the liquid, i.e. it is apt to be wetted by the liquid, in particular when cover <NUM> is fixed to the body <NUM> of pump <NUM>. In other words, the inner face <NUM> is a face inside pump <NUM>.

The outer face <NUM> is opposite to the inner face <NUM> and is a face outside pump <NUM>, i.e. it is not destined to come into contact with the liquid.

Cover <NUM>, wall <NUM> in particular, is preferably made of metal, e.g. steel, preferably stainless steel.

Cover <NUM> is preferably generally circular in shape, although it may have other shapes. Cover <NUM> is preferably provided with an opening <NUM> (<FIG>, in particular), in particular an opening of wall <NUM> apt to be crossed by a duct <NUM> of pump <NUM>, for example an inlet duct of the liquid, when cover <NUM> is fixed to body <NUM>. Preferably, opening <NUM> is circular. Opening <NUM> is preferably provided in a central zone of cover <NUM>.

Preferably, a shoulder <NUM> or collar (<FIG> and <FIG>, in particular) which delimits opening <NUM> is provided. Shoulder <NUM> extends from the upper face <NUM>. Shoulder <NUM> in particular extends outwards (i.e. upwards).

Preferably, a skirt <NUM>, or side wall, extends downwards from the outline of wall <NUM>. Cover <NUM> is preferably provided with a plurality of flaps <NUM>, for example three or four flaps, which are spaced apart from one another. The flaps <NUM> in particular extend downwards from skirt <NUM>.

The flaps <NUM> serve to fix the cover <NUM> to body <NUM>, or to another element, of pump <NUM>.

Cover <NUM> comprises a heating element <NUM>, in particular an electric heating element <NUM>. Preferably, the electric heating element <NUM> comprises a metal outer casing, for example made of stainless steel, in which at least one resistor is provided.

The electric heating element <NUM> is apt to generate heat due to the Joule effect, i.e. when it is crossed by an electric current.

The electric heating element <NUM> is tubular and in particular, is a sheathed resistor. Preferably, but not exclusively, the outer surface of the casing, which is the outermost part of the heating element <NUM>, has a substantially circular section.

The heating element <NUM> comprises a heating stretch <NUM> (<FIG> and <FIG>, in particular) and two end stretches <NUM> connected to the heating stretch <NUM>. Each end stretch <NUM> comprises a respective pin <NUM> for electrically feeding the heating element <NUM>.

The heating element <NUM> serves to heat the liquid inside pump <NUM>, in particular inside chamber <NUM>.

Preferably, but not exclusively, a single heating element <NUM> is provided. Preferably, but not necessarily, the liquid is heated exclusively by means of the heating element <NUM>.

The heating element <NUM> crosses cover <NUM>, in particular wall <NUM>, and is fixed thereto.

In other words, the heating element <NUM> crosses the entire thickness of wall <NUM>.

More in detail, the arrangement of the heating element <NUM> with respect to wall <NUM> is such that the end stretches <NUM> are above wall <NUM> and the heating stretch <NUM> is below wall <NUM>.

The end stretches <NUM> in particular protrude from the upper, or outer, side which is the side comprising the outer face <NUM>. Therefore, the end stretches <NUM> are apt to be outside pump <NUM>.

Instead, the heating stretch <NUM> is apt to be wetted by the liquid (or substantially submerged in the liquid), in particular during the operation of pump <NUM>.

Indeed, when cover <NUM> is restrained to pump <NUM>, the heating stretch <NUM> is inside pump <NUM>, in particular inside the space <NUM> (or the pumping chamber) delimited by the body <NUM> of pump <NUM>.

To ensure the heating element <NUM> crosses cover <NUM>, wall <NUM> is provided with two holes crossed by the heating element <NUM>. More in detail, the end stretches <NUM> are sealingly fixed to the inner edge of the respective hole. The fixing occurs by means of fastening means, preferably by means of welding or brazing. Preferably, a respective shoulder or collar <NUM> (<FIG>, in particular) fixed to a respective end stretch <NUM> extends outwards (i.e. upwards) from the contour of each hole to facilitate such a fixing. The holes are obstructed due to the tight fixing. Therefore, the liquid does not undesirably come out of the pumping chamber <NUM>.

With particular reference to <FIG>, wall <NUM> comprises at least one first portion <NUM> spaced apart from the heating element <NUM>.

In particular, wall <NUM> comprises at least one first portion <NUM> where the inner face <NUM> is spaced apart from the electric heating element <NUM> and, in particular, part of portion <NUM> faces the heating element <NUM>. More particularly, the inner face of the first portion <NUM> of wall <NUM> (which is a part of the inner face <NUM>) is spaced apart from the heating element <NUM>.

Moreover, wall <NUM> comprises at least one second portion <NUM> in contact, preferably directly in contact, with the heating element <NUM>, in particular with the metal casing of the heating element <NUM>.

More particularly, wall <NUM> comprises at least one second portion <NUM> where the inner face <NUM> is in contact with the electric heating element <NUM>. More particularly, the inner face of the second portion <NUM> of wall <NUM> (which is a part of the inner face <NUM>) is in contact with the heating element <NUM>.

Therefore, the heating element <NUM>, in particular the heating stretch <NUM> thereof, has at least one portion or stretch <NUM> spaced apart, in particular separate, from the inner face <NUM>, i.e. not in contact with the inner face <NUM>, and at least one portion or stretch <NUM> in contact with the inner face <NUM>.

Preferably, the surface extension of portion <NUM> is less than, in particular much less than, the surface extension of portion <NUM>.

Preferably, an empty space, which in particular may be filled by the liquid in pump <NUM>, is between stretch <NUM> and the inner face <NUM>.

Preferably, but not exclusively, there is provided a single stretch <NUM> of the heating element <NUM> to be in contact with the inner face <NUM> of wall <NUM>. That is, a single portion <NUM> of wall <NUM> is in contact with the heating element <NUM>.

The remaining part of the heating stretch <NUM>, in particular stretch <NUM>, is spaced apart from the inner face <NUM>.

Stretch <NUM> is preferably fixed to the inner face <NUM> by means of welding or brazing, in this latter case using filler material <NUM>, in particular a suitable heat conducting material.

The heating stretch <NUM> defines an axis, preferably substantially curvilinear.

It is preferable that stretch <NUM> is longer than the length of stretch <NUM> of the heating element <NUM>, in particular along said axis defined by the heating stretch <NUM>.

Cover <NUM> further comprises at least two NTC (Negative Temperature Coefficient) thermistors <NUM>, <NUM>. NTC thermistors are in themselves known. An NTC thermistor in particular is a resistor which resistance value decreases as the temperature increases. An NTC thermistor in particular is not an electro-mechanical component. Said at least two NTC thermistors <NUM>, <NUM> preferably are of the NTC-SMD (Surface-Mount Device) type.

Preferably, two NTC (preferably NTC-SMD) thermistors <NUM>, <NUM> are provided, in particular only two NTC thermistors, although more than two NTC thermistors may be provided.

The NTC thermistors <NUM>, <NUM> are fixed to wall <NUM>, in particular to the outer face <NUM>. The NTC thermistors <NUM>, <NUM> in particular are apt to act as temperature sensors. The NTC thermistors <NUM>, <NUM> are at, in particular above, the aforesaid first portion <NUM> of wall <NUM>. As mentioned above, the inner face of the first portion <NUM> is destined to be wetted by the liquid which is inside pump <NUM>.

Therefore, in other words, the NTC thermistors <NUM>, <NUM> are fixed to a portion <NUM> of wall <NUM> which inner face may be wetted by the liquid in pump <NUM>.

Advantageously, a first NTC thermistor <NUM> is distal from the aforesaid second portion <NUM> of wall <NUM>, and a second NTC thermistor <NUM> is proximal to said second portion <NUM> of wall <NUM>. In other words, the NTC thermistor <NUM> is farther away from the second portion <NUM>, and therefore farther away from stretch <NUM>; and the NTC thermistor <NUM> is closer to the second portion <NUM>, and therefore closer to stretch <NUM>.

Therefore, the NTC thermistor <NUM> is more sensitive to the temperature of the liquid, while thermistor <NUM> is more sensitive to the temperature of the heating element <NUM>. Preferably, the NTC thermistor <NUM> is apt to be sensitive substantially to the temperature of the liquid, and the NTC thermistor <NUM> is apt to be sensitive substantially to the temperature of the heating element <NUM>.

Preferably, the NTC thermistor <NUM> is at a distance which is from <NUM> to <NUM> from portion <NUM> and/or the NTC thermistor <NUM> is at a distance from <NUM> to <NUM> from portion <NUM>.

Advantageously, the NTC thermistor <NUM> and the NTC thermistor <NUM> are at, in particular above, the heating element <NUM>, in particular of stretch <NUM> of the heating element <NUM>. As mentioned above, stretch <NUM> is spaced apart from the inner face <NUM> of wall <NUM>, and in particular faces the inner face <NUM>.

More particularly, the NTC thermistor <NUM> is at portion <NUM> and also at the heating element <NUM> according to a first axis J which perpendicularly crosses wall <NUM>. In other words, the NTC thermistor <NUM>, portion <NUM> and also the heating element <NUM>, in particular stretch <NUM>, are crossed by the same first axis J which perpendicularly crosses wall <NUM>.

Moreover, the NTC thermistor <NUM> is at portion <NUM> and also at the heating element <NUM> according to a second axis K which perpendicularly crosses wall <NUM>. In other words, the NTC thermistor <NUM>, portion <NUM> and also the heating element <NUM>, in particular stretch <NUM>, are crossed by the same second axis K which perpendicularly crosses wall <NUM>.

The aforesaid first axis J and second axis K are different from each other, and in particular are parallel to each other, and in particular are rectilinear axes.

In particular, the axes J and K are parallel to the axis about which the opening <NUM> of wall <NUM> extends.

Preferably, axis J is the central axis of the NTC thermistor <NUM> and axis K is the central axis of the NTC thermistor <NUM>.

The NTC thermistors <NUM>, <NUM> preferably are not at, in particular are not above, stretch <NUM>. More in detail, the NTC thermistors <NUM>, <NUM> preferably are not even partially at, in particular are not even partially above, stretch <NUM>.

Cover <NUM> advantageously comprises a support <NUM> fixed to the outer face <NUM>. The NTC thermistor <NUM> and the NTC thermistor <NUM> are fixed to the outer face <NUM> by means of said support <NUM>. In particular, support <NUM> is between the outer face <NUM> and the NTC thermistors <NUM>, <NUM>.

Support <NUM> is made of thermally conductive material, preferably of metal, e.g. aluminum or aluminum alloy.

Preferably, a thermally conductive means, or thermally conductive paste or thermally conductive pad, preferably soft, is between support <NUM> and the outer face <NUM> in order to promote the thermal contact between support <NUM> and wall <NUM>.

Preferably, support <NUM> has a thickness from <NUM> to <NUM>. Said thickness is measured in particular, along an axis which perpendicularly crosses wall <NUM>.

Preferably, support <NUM> substantially is a plate, for example substantially rectangular-shaped.

Support <NUM> comprises a first part <NUM> in contact with said first portion <NUM> of wall <NUM>, in particular with the outer face of the first portion <NUM>. The first part <NUM> is at, in particular above, the first portion <NUM> of wall <NUM>. Preferably, the first part <NUM> is also at least partially at, in particular above, stretch <NUM> of the heating element <NUM>.

The NTC thermistors <NUM>, <NUM> are fixed to said first part <NUM> of support <NUM>.

Preferably, support <NUM> comprises a second part <NUM> in contact with said second portion <NUM> of wall <NUM>, in particular with the outer face of the second portion <NUM>.

The second part <NUM> is at, in particular above, the second portion <NUM> of wall <NUM>. In particular, the second part <NUM> is also at least partially at, in particular above, stretch <NUM> of the heating element <NUM>.

The first part <NUM> and the second part <NUM> preferably are adjacent to each other.

Preferably, support <NUM> defines an axis Z (<FIG>), in particular a longitudinal axis. Preferably, said axis Z is at, in particular is aligned with, part of stretch <NUM> of the heating element <NUM>. Preferably, the NTC thermistor <NUM> and the NTC thermistor <NUM> are aligned with each other along said axis Z.

Advantageously, the reading speed of the dry condition is thus further increased. Advantageously, support <NUM> is provided with at least one notch <NUM>, e.g. one notch <NUM>. Notch <NUM> substantially is an empty space.

Notch <NUM> is provided between two zones <NUM>, <NUM> (<FIG>) of the first part <NUM>. The two zones <NUM>, <NUM> are joined to each other by a connecting portion of support <NUM>.

Preferably, notch <NUM> is at least partially at, in particular above, said stretch <NUM>. Notch <NUM> serves in particular to limit the transmission of heat between zone <NUM> and zone <NUM> of said first part <NUM> of support <NUM>.

Advantageously, the NTC thermistor <NUM> is fixed to zone <NUM> and the NTC thermistor <NUM> is fixed to zone <NUM>.

Advantageously, the NTC thermistor <NUM> is thus particularly sensitive to the temperature of the liquid, while the NTC thermistor <NUM> is particularly sensitive to the temperature of the heating element <NUM>.

In particular, the NTC thermistor <NUM> advantageously is apt to detect a temperature which conforms more with the temperature of the water during the regular operation of pump <NUM>, while the NTC thermistor <NUM> is closer to the hot zone and therefore is more reactive in case of lack of water because it is more sensitive to the temperature of the heating element <NUM>. In particular, as the NTC thermistor <NUM> and the NTC thermistor <NUM> are at stretch <NUM>, in case of lack of water, both the NTC thermistor <NUM> and the NTC thermistor <NUM> read the increase of the temperature due to the superheating of the heating element <NUM>.

Notch <NUM> advantageously allows the difference in temperature between the NTC thermistor <NUM> and the NTC thermistor <NUM> to be adjusted and allows the NTC thermistor <NUM> to be substantially at the same temperature as the water.

Zone <NUM> of the first part <NUM> of support <NUM> is distal from the second part <NUM> of support <NUM>.

Zone <NUM> of the first part <NUM> of support <NUM> is proximal, in particular adjacent, to the second part <NUM> of support <NUM>.

Preferably, notch <NUM> has a thickness equal to the thickness of support <NUM>. Preferably, notch <NUM> is obtained starting from a portion of the periphery of support <NUM>.

The width and the depth (or length) of notch <NUM> may be selected according to the operating needs.

Preferably, notch <NUM> is between the first NTC thermistor <NUM> and the second NTC thermistor <NUM>, i.e. preferably notch <NUM> extends between the first NTC thermistor <NUM> and the second NTC thermistor <NUM>.

Support <NUM> is provided with at least one electrically conductive track <NUM> fixed thereto, e.g. one conductive track <NUM> (<FIG> and <FIG>).

The NTC thermistors <NUM>, <NUM> are fixed to the electrically conductive track <NUM>, in particular so as to be crossed by an electrical signal with which an ohmic and therefore temperature value may be associated, therethrough.

A dielectric layer is provided between the electrically conductive track <NUM> and support <NUM>.

An electric connector <NUM>, preferably multipolar, is also fixed to support <NUM>. For example, the electric connector <NUM> is three-pole (as shown in the drawings) and in particular, is provided with three electrically conductive legs <NUM> (<FIG>) welded to the conductive track <NUM>.

The electric connector <NUM> is apt to receive an electrical signal processed by the NTC thermistors <NUM>, <NUM> by means of the conductive track <NUM>.

Preferably, the electric connector <NUM> is partially arranged at said notch <NUM>, is partially fixed to said first zone <NUM> of said first part <NUM> of support <NUM>, and is partially fixed to said second zone <NUM> of said first part <NUM> of support <NUM>.

In other words, the electric connector <NUM> substantially serves as bridge between the first zone <NUM> and the second zone <NUM> so as to provide a structural support to compensate for any structural weaknesses induced by the presence of notch <NUM>. Preferably, the electric connector <NUM> is only partly above notch <NUM>.

The component <NUM> (<FIG> and <FIG>) comprising the support <NUM>, the NTC thermistors <NUM>, <NUM>, the electrically conductive track <NUM> and preferably also the electric connector <NUM>, substantially is an electronic board which in particular, is a pre-assembled component.

Preferably, support <NUM> is fixed to wall <NUM> so as to be disassembled from wall <NUM>, in particular so as to be disassembled without damaging components of cover <NUM>.

For example, as shown in <FIG>, support <NUM> is fixed to wall <NUM> by means of fastening means <NUM> which provide a screw coupling, for example of the nut and stud type, the stud being fixed to wall <NUM>, preferably welded to wall <NUM>. Preferably, first fastening means <NUM>, for example a first nut-stud pair <NUM>, are fixed to portion <NUM>, in particular at stretch <NUM> of the heating element <NUM>, and second fastening means <NUM>, for example a second nut-stud pair <NUM>, are fixed to portion <NUM>, in particular at stretch <NUM> of the heating element <NUM>.

In the variant shown in <FIG>, the fastening means comprise an elastic body <NUM> which applies a force on support <NUM> to fix it to wall <NUM>.

In particular, the elastic body <NUM> comprises two flaps <NUM>, <NUM> between which a central part <NUM> is provided. The flaps <NUM>, <NUM> are fixed, e.g. welded, to wall <NUM> so as to bend the middle part <NUM> so that it applies a force on support <NUM>.

Additionally or alternatively to the aforesaid fastening means <NUM>, <NUM>, support <NUM> may also be welded or brazed to wall <NUM> or fixed by means of an adhesive.

In addition to the NTC thermistors <NUM>, <NUM>, cover <NUM> may in any case be provided with one or more temperature control devices of the electro-mechanical type. For example, cover <NUM> may be provided with a thermostat, in particular of the electro-mechanical and/or thermal fuse type.

Said thermostat and/or thermal fuse in particular are fixed to the outer face <NUM>.

Claim 1:
A cover (<NUM>) for a pump (<NUM>) for a liquid for a household appliance, in particular for a dishwasher or a washing machine;
the cover (<NUM>) comprising
- a wall (<NUM>) having
an inner face (<NUM>) destined to come into contact with the liquid and
an outer face (<NUM>), opposite to the inner face (<NUM>);
- an electric heating element (<NUM>) which crosses said wall (<NUM>), whereby said at least one electric heating element (<NUM>) is apt to come into contact with the liquid;
wherein said wall (<NUM>) comprises at least one first portion (<NUM>) where the inner face (<NUM>) is spaced apart from the electric heating element (<NUM>);
wherein said wall (<NUM>) comprises at least one second portion (<NUM>) where the inner face (<NUM>) is in contact with the electric heating element (<NUM>);
- a support (<NUM>) fixed to the outer face (<NUM>);
characterized in that
the cover (<NUM>) further comprises at least a first NTC thermistor (<NUM>) and a second NTC thermistor (<NUM>) which are fixed to the outer face (<NUM>) at said first portion (<NUM>) of the wall (<NUM>);
wherein the first NTC thermistor (<NUM>) is distal from said second portion (<NUM>) of the wall (<NUM>), and the second NTC thermistor (<NUM>) is proximal to said second portion (<NUM>) of the wall (<NUM>);
wherein the first NTC thermistor (<NUM>) and the second NTC thermistor (<NUM>) are at a stretch (<NUM>) of the heating element (<NUM>) spaced apart from said first portion (<NUM>) of the wall (<NUM>) and facing said first portion (<NUM>) of the wall (<NUM>);
wherein the first NTC thermistor (<NUM>) and the second NTC thermistor (<NUM>) are fixed to the outer face (<NUM>) by means of said support (<NUM>);
wherein said support (<NUM>) comprises a first part (<NUM>) in contact with said first portion (<NUM>) of the wall (<NUM>);
wherein the first NTC thermistor (<NUM>) and the second NTC thermistor (<NUM>) are fixed to said first part (<NUM>) of the support (<NUM>);
wherein said first part (<NUM>) of the support (<NUM>) comprises a first zone (<NUM>) and a second zone (<NUM>), between which at least one notch (<NUM>) is provided, in particular to limit the transmission of heat between the first zone (<NUM>) and the second zone (<NUM>) of said first part (<NUM>) of the support (<NUM>);
wherein the first NTC thermistor (<NUM>) is fixed to the first zone (<NUM>) and the second NTC thermistor (<NUM>) is fixed to the second zone (<NUM>).