EP3876808A1

EP3876808A1 - A dishwasher comprising a heater

Info

Publication number: EP3876808A1
Application number: EP19779870.5A
Authority: EP
Inventors: Yusuf Koc; Murat Kantas; Tumay CITAK; Filiz CELIK
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2018-11-06
Filing date: 2019-09-30
Publication date: 2021-09-15
Also published as: WO2020094295A1

Abstract

The present invention relates to a dishwasher (1) comprising a body (2); a tub (7) which is disposed in the body (2) and wherein the washing process is performed; a heater (3) which heats the air used for drying the dishes; a casing (5) which covers the heater (3); a sensor unit (6) which detects an item on the casing (5); and a control unit (4) which controls the operation of the heater (3).

Description

[Title established by the ISA under Rule 37.2] A DISHWASHER COMPRISING A HEATER

The present invention relates to a safely operated dishwasher.
In dishwashers, a washing cycle is completed by successively performing the cold washing, main washing, rinsing and drying steps. The drying step which is one of the main steps of the washing cycle is performed by means of a heater provided in the dishwasher. Said heater enables water droplets and residues remaining on the washed and cleaned dishes to be removed by way of vaporization.
The performance of the drying step is directly related to the heater. In order to obtain dishes which are clean and free of water spots when the washing process is completed, the drying step and the heater which performs said step have a very important role. The heater is positioned at a lower region of the body so as to enable the air heated by the heater to raise within the body of the dishwasher and to easily reach every area.
In the dishwashers, especially small plastic items in the racks wherein the dishes to be cleaned are placed may fall of the racks with the effect of the pressurized water sprayed during the washing process. If said items fall onto the casing over the heater at high temperatures, the plastic material may melt and this material may stick onto the casing, causing unwanted odors in the machine.
The state of the art Korean Patent Document No. KR20160025342 discloses the control of the operation of the heater in the dishwasher by means of a fuse and a load detection device.
The aim of the present invention is the realization of a dishwasher wherein the operation of the heater is controlled by detecting the items on the casing provided over the heater which provides the drying process in the dishwashers.
The dishwasher of the present invention comprises a sensor unit which detects items which may melt due to high temperatures on the casing and may stick to the dishwasher.
The drying step in the dishwashers is performed by means of the hot air provided by the heater. The temperature of the heater is determined by the producer to be at least 100ºC in order to vaporize water remaining on the dishes and to ensure hygiene. The heater which provides said temperature values must be positioned at a safe area on the base of the tub in the dishwasher. Therefore, a casing is provided over the heater. A purpose of the casing is to enclose the heater so as to prevent the water in the tub, wherein the washing process is performed, from damaging the heater. Another purpose of the casing is to prevent items falling off especially during the washing process from directly contacting the heater. However, in such a case, if there is an item on the casing, said item may melt and stick onto the casing due to the high temperature of the heater. Therefore, the casing cannot prevent said unwanted incidents from occurring by itself. In such a case the heater must be stopped.
The dishwasher of the present invention comprises a control unit which stops the operation of the heater when the sensor unit detects a foreign item on the case over the heater.
The sensor unit and the control unit intercommunicate, and the control unit controls the operation of the heater depending on the data received from the sensor unit.
In an embodiment of the present invention, the sensor unit comprises at least one of the weight sensor or the temperature sensor. Thus, detection can be performed according to different parameters such as weight, temperature, etc.
The model embodiments relating to the dishwasher realized in order to attain the aim of the present invention are illustrated in the attached figures, where:
Figure 1 - is a general view of a dishwasher of the present invention.
Figure 2 - is the top perspective view of the part of the tub containing the casing in the dishwasher of the present invention.
Figure 3 - is the detailed view of the heater, the casing and the sensor unit which are placed onto the base of the tub in the dishwasher of the present invention.
Figure 4 - is the top perspective view of the part of the dishwasher of the present invention containing the heater.
Figure 5 - is the detailed view of the casing and the sensor unit comprising the insulation element in an embodiment of the dishwasher of the present invention.
The elements illustrated in the figures are numbered as follows:

Dishwasher
Body
Heater
Control unit
Casing
Sensor unit
Tub
Insulation element

The dishwasher (1) comprises a body (2); a tub (7) which is disposed in the body (2) and wherein the washing process is performed; a heater (3) which heats the air used for drying the dishes; and a casing (5) which covers the heater (3).
The dishwasher (1) of the present invention comprises a sensor unit (6) which detects an item on the casing (5) and a control unit (4) which controls the operation of the heater (3).
In the dishwasher (1), the washing process comprises the steps of cold washing, main washing, rinsing and drying. The drying step is a step wherein the water droplets and dirt particles, if any, remaining on the dishes after the cold washing, main washing and rinsing steps are removed by means of hot air. In said step, the drying process is performed by heating the air to a certain temperature by means of the heater (3). In order to benefit from the ability of the air to rise up and to disperse the air inside the body (2), the heater (3) is positioned on the base of the tub (7). Thus, in the drying step, the hot air can be easily moved inside the tub (7). The dishes may fall onto the base of the tub (7) during the washing step with the effect of the pressurized water or while being placed into the racks before the washing process. In order to prevent incidents such as the melting of said items due to the high temperature of the heater (3), etc., the dishwasher (1) of the present invention comprises a sensor unit (6) which detects said items. By means of the sensor unit (6), the items on the casing (5) are detected. The sensor unit (6) can detect the presence of the item on the casing (5) by using parameters such as weight, temperature, etc. Thus, when an item is detected on the casing (5), the sensor unit (6) transmits the information of the presence of a foreign item to the control unit (4). In such a case, the control unit (4) stops the operation of the heater (3). Thus, the operation of the dishwasher (1) is stopped in the drying step and the risk of the item on the casing (5) melting, etc. is prevented.
The surface of the casing (5) facing the base of the tub (7) wherein the washing process is performed is the upper surface, and the surface of the casing (5) facing the heater (3) is the lower surface. As a matter of course, the casing (5) is produced from metal material resistant to the high temperature of the heater (3) and heats up due to the temperature of the heater (3).
In a preferred embodiment of the present invention, the sensor unit (6) is positioned at a point on the lower surface of the casing (5) which is not affected by the temperature of the heater (3). Thus, by preventing the sensor unit (6) from being affected by water and dirt during the washing process, erroneous measurements are prevented, providing a more accurate detection and the sensor unit (6) is prevented from being damaged by the high temperature of the heater (3).
In another embodiment of the present invention, the dishwasher (1) comprises an insulation element (8) provided between the sensor unit (6) and the casing (5). Consequently, the sensor unit (6) is protected against the high temperature of the heater (3).
In an embodiment of the present invention, the sensor unit (6) comprises at least one weight sensor. In this embodiment, the item on the casing (5) is detected due to the weight of said item. In order to prevent expected residues (water droplet, dirt, etc.) on the casing (5) during the washing process from being detected as foreign items, limitations are imposed on time and mass. The sensor unit (6) comprising the weight sensor detects the mass of the item on the casing (5).
In a preferred embodiment of the present invention, the sensor unit (6) comprises a weight sensor which detects a mass of at least 5 grams in order to prevent unnecessary stopping of the heater (3). Thus, dirt, residues and water droplets which are much lighter than any possible items on the casing (5) are prevented from being detected as foreign items, and the heater (3) is not unnecessarily stopped.
In an embodiment of the present invention, the control unit (4) comprises a timer in order to evaluate the data received from the weight sensor after a predetermined period of time elapses. In this embodiment, upon detecting the item on the casing longer than a period of time predetermined by the producer, the sensor unit (6) communicates with the control unit (4) such that the heater (3) is stopped. It is possible for the water droplets and dirt residues which may remain on the casing (5) by the nature of the washing process to vaporize or fall to another region with the effect of the hot air provided by the heater (3). Therefore, the item which does not move from over the casing (5) during said defined period of time is detected as a foreign item. In a preferred embodiment of the present invention, said period of time determined by the producer is 30 seconds.
In another embodiment of the present invention, the sensor unit (6) comprises at least one temperature sensor. When an item is on the casing (5), the surface of the casing (5) cools down late since the item forms an additional layer for heat transfer, the temperature of the heater (3) will be measured higher than expected. In this embodiment, the sensor unit (6) measures the temperature of the heater (3) and thus detects the item on the casing (5). Consequently, if the sensor unit (6) measures a temperature higher than the temperature value predetermined by the producer for the heater (3) to carry out the drying process, the control unit (4) stops the operation of the heater (3).
In an embodiment of the present invention, the sensor unit (6) may comprise at least one weight sensor and/or at least one temperature sensor which can be separately controlled.
By means of the dishwasher (1) of the present invention, when an item is present on the casing (5) over the heater (3), the risk of unwanted incidents such as the melting of plastic items, etc. due to high temperatures is prevented.

Claims

A dishwasher (1) comprising a body (2); a tub (7) which is disposed in the body (2) and wherein the washing process is performed; a heater (3) which heats the air used for drying the dishes; and a casing (5) which covers the heater (3), characterized by a sensor unit (6) which detects an item on the casing (5) and a control unit (4) which controls the operation of the heater (3).
A dishwasher (1) as in Claim 1, characterized by the sensor unit (6) comprising at least one weight sensor for detecting the weight of the item on the casing (5).
A dishwasher (1) as in Claim 1 or Claim 2, characterized by the sensor unit (6) comprising the weight sensor which detects a mass of at least 5 grams.
A dishwasher (1) as in any one of the above claims, characterized by the control unit (4) which comprises a timer.
A dishwasher (1) as in Claim 1, characterized by the sensor unit (6) comprising a temperature sensor which measures the temperature of the heater (3).
A dishwasher (1) as in any one of the above claims, characterized by an insulation element (8) which is arranged between the sensor unit (6) and the casing (5).