EP2215301B1 - Method for operating a washing machine having a heating unit - Google Patents

Abstract

The invention in one embodiment relates to a method for operating a washing machine having a heating unit, wherein the heating unit comprises a carrier and at least one planar heating element disposed thereon. At least one first heating element is attached to the carrier in a planar manner, wherein the carrier has a recess extending in the longitudinal direction in the center region. The washing machine has a washing machine barrel and a drum therein, wherein the heating unit is displaced at the bottom in the washing machine barrel outside of the drum. A heating element is provided on the outside of the carrier in the region of the recess in the region along an apex, or along an apex of the recess, wherein only said heating element is operated in the region of the recess for creating steam in the washing machine.

Description

Field of application and state of the art

The invention relates to a method for operating a washing machine with a heating device, in particular for generating steam in the washing machine.

It is known from the prior art to use in washing machines electric heaters with electric heating elements, which are arranged in a washing machine tub of the washing machine below a drum (see for example the EP 0 352 499 ). For example, they heat the water needed for washing to a desired temperature. For this purpose, so-called tubular heaters are usually used, but it can also be used flat heating elements.

Task and solution

The invention has for its object to provide an aforementioned method, can be overcome with the disadvantages of the prior art and in particular the scope of a washing machine can be extended without much effort and preferably the heater can be used for other purposes.

This edition is achieved by a method having the features of claim 1. Advantageous and preferred embodiments of the invention are the subject of further claims and are explained in more detail below.

It is provided that the heating device has a carrier and at least one planar heating element arranged thereon. The heating element is applied flat on the support, wherein above all the areal or planar character of the heating element is important. The carrier has, in a region, advantageously in a central region, a depression which runs over a greater length or runs along the carrier. As a result, as will be explained in more detail below, a defined outflow of water from the carrier can be achieved. Furthermore, a certain concentration of water can be achieved in a certain range in order, for example, to be able to evaporate or heat it in a particularly targeted and efficient manner. The above-described heater is placed at the bottom of the washing machine tub between its lower portion and the drum. A possible domed shape of the heater can advantageously serve to ensure that the distance between the drum and the washing machine tub does not have to be too large. From the curvature or the radius forth, the heater can correspond to the washing machine tub.

According to the invention, steam is generated in the washing machine or with the heating device. For this purpose, only one heating element is operated, which is located in the region of the depression, as has been described above. On the one hand, this saves energy, since other heating elements arranged next to it, which usually have less water in their vicinity, are not operated, since they would be less efficient. They would contribute much less to steam production. Furthermore, water can be introduced as well as possible in the depression, which is why it can be heated particularly well here for evaporation. Again, a temperature and thus the evaporation can be controlled as well as possible via a temperature sensor. Furthermore, this can for the evaporation provided water by a corresponding pump or other similar device so applied to the heater or sprayed that it collects in the well and is completely evaporated before draining.

In an embodiment of the invention, the carrier may have in its longitudinal course a longitudinal groove as said recess. The longitudinal channel can basically be designed as desired, it is advantageous that it is rounded. Particularly advantageously, the entire carrier is substantially curved or rounded with a channel shape or in the manner of a spade and forms itself with its course the depression. A curvature may be formed substantially uniform, in particular over the entire length of the carrier away. This means that the water can drain particularly well from the carrier in the manner of a gutter or even before it can collect as well as possible. Although it is in principle possible to provide a plurality of recesses on the carrier, but preferably a single recess.

The heater may fall after installation in the washing machine in its longitudinal course, preferably slightly inclined, so that thereon water runs off. For this purpose, the channel shape is advantageous because it both causes a certain quantitative concentration of the water thereon or flowing on it and also allows a good drainage. Particularly advantageously, the heating device drops to its free end. In this case, the heating device can advantageously be installed so that it runs with its longitudinal direction or the direction of the recess approximately parallel to a rotational axis of the drum.

Like the recess, at least one heating element of the carrier advantageously extends over its substantial length. Such a heating element can either be provided as a full surface or cover a surface and, for example, be meander-shaped.

In principle, it is possible to provide heating elements on both sides of the carrier. Advantageously, a heating element is provided on the outside of the carrier, ie in the region where the depression projects beyond the course of the carrier or along a vertex or along a vertex line of the depression. It can thus be achieved that, with the heating device built into the washing machine, the depression or its apex line forms the deepest region of the heating device. Here the water collects. It can happen on the one hand. In any case, however, in this area, where the water is the longest, the heating element is also arranged for optimum heating or evaporation of this water. The arrangement of the heating element on the outside of the carrier or in the installed state at the bottom also has the advantage that lime deposits or the like. not directly on the heating element are present, but only on the support surface. Particularly advantageous are all heating elements on the same side, namely the outside or bottom, provided.

In an embodiment of the invention, at least one first heating element as mentioned above is provided in the region of the depression and at least one second heating element is located next to the side edge or to the longitudinal side of the carrier. In each case, in each case second heating elements are provided on both sides of the first heating element, which heating elements are in particular the same and the same size. It is advantageous if the first heating element and the second heating elements can each be controlled separately from each other depending on the desired mode. This will be explained in more detail below.

In an embodiment of the invention, a temperature sensor may be provided on the carrier. This can also be designed in thick film technology. Advantageously, the temperature sensor, similar to the heating elements, provided on the outside or on the underside of the recess on the carrier, in particular exactly at the recess. So can the Temperature sensor measure the temperature of the heater or especially of the heating element at the recess and can be concluded that a water temperature when the heating element is completely immersed in water for a heating operation, or for determining a temperature for an evaporator operation. In yet another embodiment of the invention, two such temperature sensors are provided, both on the same side. In this case, it may be advantageous to provide the temperature sensors in each case close to one end of the carrier, in particular in each case at the recess. Thus, especially in the evaporator operation according to the invention, the temperature of the heater can be controlled well. An alternative possibility for measuring the temperature or for replacing the aforementioned temperature sensors is to measure the electrical resistance of the heating element, as is generally known to those skilled in the art. This electrical resistance may just be an NTC or PTC resistor for better measurement.

In yet another embodiment of the invention, a conductivity measuring device may be provided on the carrier. It may be constructed, for example, in thick film technology and have two electrodes, which are covered with a cover layer and protected against the wash liquor or the wash liquor. Such conductivity measuring devices are basically known from the prior art, see for example the DE 10 2005 007 935 A1 or the DE 10 2006 025 622 A1 , This conductivity measuring device can serve to determine properties of the wash liquor, in particular a degree of contamination or the like.

In a further embodiment of the invention, the carrier may have a functional layer. This may, for example, have an anti-adhesion effect, in particular in the manner of a PTFE layer. Other functions may be insulation properties for electrical insulation or resistance to aggressive media such as water, steam or lime, especially in the wash liquor. An aforementioned functional layer having an anti-adhesive effect is advantageous, above all, on an upper side of the heating device, so that no deposits can form here because of the water located thereon.

By the heater, a heating power of just under 1000 watts can be achieved on the heating element along the depression. Advantageously, the heating power is less than 800 watts, since then according to the regulations of the energy supplier switching or clocking the individual heating elements is possible as often as possible. By arranged adjacent heating elements, a total power of up to about 2000 watts can be achieved.

In a further operating mode of the heating device or the washing machine, it can be operated so that the water is to be heated in the washing machine or in the washing machine tub for a washing process. Then advantageously all heating elements of the heater are operated or controlled, with their precise control can be done by the aforementioned temperature sensors.

These and other features will become apparent from the claims but also from the description and drawings, wherein the individual features each alone or more in the form of sub-combination in one embodiment of the invention and in other areas be realized and advantageous and protectable Represent embodiments for which protection is claimed here. The subdivision of the application into individual sections as well as intermediate headings does not restrict the general validity of the statements made thereunder.

Brief description of the drawings

Fig. 1

eine Schrägansicht von unten auf eine Heizeinrichtung,

Fig. 2

eine Schrägansicht von oben auf die Heizeinrichtung gemäß Fig. 1,

Fig. 3

die Einbausituation der Heizeinrichtung aus Fig. 1 in eine Waschmaschine von vorne und

Fig. 4

die Einbausituation gemäß Fig. 3 in Seitenansicht.

An embodiment of the invention is shown schematically in the drawings and will be explained in more detail below. In the drawings show:

Fig. 1

an oblique view from below of a heater,

Fig. 2

an oblique view from above the heater according to Fig. 1 .

Fig. 3

the installation situation of the heater off Fig. 1 in a washing machine from the front and

Fig. 4

the installation situation according to Fig. 3 in side view.

Detailed description of the embodiment

In Fig. 1 a heater 11 according to the invention is shown in an oblique view from below. It consists of a carrier 13 which is elongated and curved in the manner of a round groove. The carrier 13 is advantageously made of a suitable steel for such applications, for example, coated with a corresponding insulating layer which is glass-containing or enamel. This is from the DE 19803506 A1 known. Such an insulation layer is generally advantageous on the outside 14, which in the installed state according to 3 and 4 is below, provided, possibly also on the inside 15.

The carrier 13 has on the outer side 14, so to speak at the apex of the channel, an elongated first heating element 17. This is shown as a surface, but in detail may also be designed differently, for example, with the aforementioned elongated meander shape odgl .. Separated by trenches or with a certain distance to a second heating element 18a and a third heating element 18b are provided on both sides. These may in principle be similar, ie either full-surface or meandering. Furthermore, although the heating elements may each have the same power, below But also different performance, in particular, the first or middle heating element 17 may have the strongest performance.

Furthermore, in the region of the first heating element 17 or along the apex line of the channel of the carrier 13, a temperature sensor 20a near the one end and a temperature sensor 20b near the other end are provided. These are designed as conventional temperature sensors in thick film technology, in particular for temperature measurement by resistance measurement.

Both the heating elements 17 and 18a and 18b and the temperature sensors 20a and 20b are connected via webs not shown to a protruding portion 24 of the carrier 13 at its one end with connection pads 25. The terminal pads 25 are formed as metallized areas on the support 13 in the area 24 and allow the attachment of a group connector for electrical connection, as this Fig. 4 shows. The protruding region 24 is separated from the rest of the carrier 13 by a circumferential seal 22. This seal 22 is made of rubber and is sprayed by two-component syringes directly onto the carrier 13 or this is encapsulated. This ensures a good sealing effect and good mechanical strength as a structural unit. Alternatively and also advantageously, the heating device 11 may be encapsulated with a plastic flange, so that it can be mounted directly in a washing machine vat. Then the plastic flange is the second component. This also allows a good sealing function can be achieved.

In Fig. 3 a washing machine 28 is shown in a sectional view from the front. It has a drum 29 in a washing machine tub 30 in the usual way. The drum 29 can rotate about the central axis of rotation. In the intermediate space between the drum 29 and washing machine tub 30, the heating device 11 is in the lower area Fig. 1 arranged and is completely in wash liquor Submerged 32, of course, collects in the lower portion of the washing machine tub 30. The side view Fig. 4 makes it clear how to the projecting portion 24 with the connector panels 25 according to Fig. 1 a connector plug 26 is plugged for electrical connection of the entire heater 11, so both the heating elements 17 and 18a and 18b and the temperature sensors 20a and 20b. The obliquely sloping installation of the heater 11 in the washing machine 28 is inventively set by the installation situation, under certain circumstances, appropriate supports or holders may be provided. On the one hand, this inclination causes the water from the heating device 11 to drain off well when the washing liquor is being pumped off, so that no residues and thus soiling result. As a result, the heating effect of the heater 11 in the wash liquor 32 is not affected.

For the evaporator operation according to the invention, it is possible not only generally water in the washing machine 28 via an inlet 34 with valve 35 for washing. Even with a dry washing machine tub 30, water can be applied via the inlet 34, which is arranged precisely above the heating device 11 close to the seal 22, via the valve 35, and a small amount of water can be applied. In this case, then, as in the heating operation, for heating the wash liquor 32, all the heating elements, ie all three, operated, but only the first heating element 17. Namely, this heated the middle area in which a small amount of water on the Inside 15 of the heater 11 comes, is located and runs to the free end. Thus, this water can be evaporated by strong and rapid heating, which spreads inside the washing machine 28 and especially inside the drum 29 of the steam. This can be used for a special treatment of laundry therein, for example for refreshment. The channel shape of the heater 11 causes the collection of water just in the vicinity of the apex of the channel and thus at the middle heater. Furthermore can be achieved by the sloping arrangement of the heater here, a movement and distribution of water over the entire first heating element 17.

The energy input can be regulated via the temperature sensors 20a and 20b on the heating device 11 by measuring the temperature, depending on the steam generating operation or the heating operation of the heating device 11. Furthermore, a measurement of the properties of the washing liquor can take place by means of a conductivity measuring device (not shown). Finally, it is still possible to provide the inside 15 of the carrier 13, on which neither heating elements nor other sensors are provided here in the exemplary embodiment, with an anti-adhesion coating as mentioned above. Even so, in addition to the oblique installation deposits can be avoided or at least greatly reduced.

Claims (14)

1. A method for operating a washing machine (28) having a heating unit (11), where the heating unit has a carrier (13) and multiple planar heating elements (17, 18) arranged thereon, where at least one first heating element (17) is attached in planar manner to the carrier (13) and where the carrier has in a central region a recess running lengthways, where the washing machine (28) has a washing machine barrel (30) and a drum (29) therein, and where the heating unit (11) is arranged at the bottom inside the washing machine barrel (30) and outside the drum (29), one heating element is provided on the outside of the carrier in the region of the recess in the region along an apex or along an apex line of the recess, where only the heating element (17) in the region of the recess is operated for steam generation inside the washing machine (28), characterized in that the first heating element (17) is provided in the region of the recess and at least a second heating element (18) is arranged adjacent to it towards the lateral edge.
2. The method according to claim 1, characterized in that at least one temperature sensor (20) is provided on the carrier (13), where the temperature sensor (20) is preferably provided precisely on the outside (14) of the recess on the carrier (13), where the temperature of this heating unit is measured using this temperature sensor (20) for control of the heating element (17), and its power is regulated depending on this temperature.
3. The method according to claim 2, characterized in that two temperature sensors (20) are provided on the outside (14) of the carrier (13), where preferably one temperature sensor (20a) is provided close to one end (24) of the carrier (13) and the other temperature sensor (20b) close to the other end in the longitudinal course parallel to the recess.
4. The method according to any of the preceding claims, characterized in that the electrical resistance of the heating element (17, 18) is measured and a temperature of the heating element or of the carrier (13) is determined from it.
5. The method according to any of the preceding claims, characterized in that all heating elements (17, 18) of the heating unit (11) are operated for heating up water.
6. The method according to any of the preceding claims, characterized in that the heating unit (11) is arranged close to the lowest region of the washing machine barrel.
7. The method according to any of the preceding claims, characterized in that the heating unit (11) is installed in the washing machine barrel (30) such that in its longitudinal course it slopes for flow-off of water at or on the heating unit (11), where preferably the heating unit is installed inside the washing machine (28) such that the recess is pointing downwards.
8. The method according to any of the preceding claims, characterized in that the recess extends over the main length of the carrier (13).
9. The method according to any of the preceding claims, characterized in that the carrier (13) has in its longitudinal course a longitudinal channel to form the recess, in particular a rounded longitudinal channel, where it is preferably substantially curved overall with a channel form or in the shape of a spade.
10. The method according to any of the preceding claims, characterized in that the longitudinal direction of the heating unit (11) is approximately parallel to a rotation axis of the drum (29).
11. The method according to any of the preceding claims, characterized in that at least the first heating element (17) extends in the region of the recess over the main length of the carrier.
12. The method according to any of the preceding claims, characterized in that on each of both sides of the first heating element (17) at the recess a further second heating element (18) is provided, and said heating elements can preferably be controlled separately.
13. The method according to any of the preceding claims, characterized in that a conductivity measuring device can be provided on the carrier (13), in particular a conductivity measuring device designed using thick-film technology with two electrodes and a top layer covering it, where the conductivity measuring device is preferably provided on the outside (14) of the carrier (13) at the recess.
14. The method according to any of the preceding claims, characterized in that the heating capacity of the first heating element (17) at the recess is less than 800 W.

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