EP2654547A2

EP2654547A2 - A dishwasher comprising a dehumidifying unit

Info

Publication number: EP2654547A2
Application number: EP11794459.5A
Authority: EP
Inventors: Yusuf Koc; Levent Akdag; Murat Kantas; Arda YALCIN
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2010-12-24
Filing date: 2011-12-06
Publication date: 2013-10-30
Also published as: WO2012084488A2; WO2012084488A3

Abstract

The present invention relates to a dishwasher (1) comprising a tub (2) wherein the washing process is performed, a tub inlet (3) providing air entrance into the tub (2), a tub outlet (4) providing the air in the tub (2) to be discharged, an air channel (5) located outside the tub (2), providing a closed air circuit between the tub outlet (4) and the tub inlet (3), a fan (6) disposed on the air channel (5) and providing the air in the tub (2) to be sucked and a dehumidifying unit (7) disposed on the air channel (5), and wherein the desiccant material (8) particles located in the dehumidifying unit (7) are effectively regenerated.

Description

A DISHWASHER COMPRISING A DEHUMIDIFYING UNIT

The present invention relates to a dishwasher comprising a dehumidifying unit that provides the drying process to be performed effectively.
In the dehumidifying step of dishwasher washing programs, it is aimed to remove the water remaining on the dishes and also to prevent the moisture in the tub from leaving stains on the dishes getting cold by condensing. The last rinsing step is performed with hot water in order to remove the water remaining on the dishes in an easier way in the dehumidification step. This requires a great amount of energy to be consumed for heating the water. In the dehumidification step after the hot rinsing step, humid air in the tub is delivered to the outer environment by means of a fan. In some dishwashers, an additional air channel that delivers the humid air received from the tub to the tub again by condensing it thereon is disposed near this line. However, moisture in the tub cannot be completely discharged and causes stains on the dishes by condensing. Moreover, when the user opens the cover of the dishwasher, air mass with high temperature remaining in the tub at once exits to the outer environment and can cause the user to be exposed to hot vapor.
In order to solve the said problem, dehumidifying elements comprising reversible type moisture adsorbent materials are used. Adsorbent materials can adsorb moisture up to the saturation point and at that moment emit heat to its surroundings. In the state of the art, zeolite is used as moisture adsorbent in dishwashers. Humid air received from the tub by means of the fan is sent to the zeolite-comprising container and after heating up and leaving its moisture therein, the said air is again directed into the tub. By means of this process, an effective dehumidification process is realized by vaporizing the water on the dishes without requiring the realization of the hot rinsing step. Zeolite that fills its moisture adsorption capacity during this time, is regenerated at the next washing step by being heated up to high temperatures by means of a heater placed therein or thereabout and can be used again.
Since zeolite regeneration is realized at very high temperatures, an effective regeneration cannot be provided with a heater outside the container. In cases where the heater is disposed inside the chamber, since zeolite particles directly contacting the heater are exposed to high amount of heat, they burn and lose their desiccation characteristic after some time. In this case, the dishwasher cannot perform an effective dehumidifying in the course of time and makes the user thinks that the machine is broken down. This causes customer dissatisfaction and increase in maintenance and repair rate.
In state of the art International Patent Application No. WO2006061287, positioning of the heater in the flow direction of the air, just before the inlet of the chamber comprising reversible desiccant material is explained.
In the state of the art European Patent Document No. EP358279, a dishwasher is described, comprising a zeolite container positioned around a pipe-type water heater. In this embodiment, waste heat occurring around the heater during the water heating process is used for zeolite regeneration.
In the state of the art European Patent Document No. EP1674030, a dishwasher is described, comprising a chamber having desiccant material therein between the outer cabinet and the tub. In this embodiment, at least one heater is disposed between the desiccant materials arranged as plates so as to make thermal contact with the particles.
The aim of the present invention is the realization of a dishwasher the drying effectiveness of which is increased.
In the dishwasher realized in order to attain the aim of the present invention, explicated in the first claim and the respective claims thereof, a dehumidifying unit having a desiccant material and a heater, an air channel providing the air circulation between the dehumidifying unit and the tub, and a movement mechanism are disposed.
The dishwasher of the present invention comprises a movement mechanism providing the desiccant material to be stirred by moving the heater. The movement mechanism that is activated during the regeneration of the desiccant material moves the heater to which it is connected, in the chamber. The heater is brought to the predetermined positions in the chamber at certain moments of the regeneration process.
In an embodiment of the present invention, the heater moves in the horizontal direction along the container. In this embodiment, the heater performs its movement by going back and forth preferably in the direction between the surface where the inlet port is disposed and the surface where the outlet port is disposed.
In another embodiment of the present invention, at least one opening is located on the container. The ends of the heater are taken out of the container through the openings to be mounted to the movement mechanism. In this embodiment, preferably two openings are present. Two ends of the heater are taken out through these openings and moved along the opening with the effect of the movement mechanism.
In another embodiment of the present invention, a sealing element is disposed on the container. The sealing element occupies the gap between the opening and the heater, thus preventing the desiccant material to leave the container. The sealing element is produced from a material that is flexible and resistant to high temperatures.
In an embodiment of the present invention, the dehumidifying unit comprises temperature sensors that are plunged into the container and that contact the desiccant material particles. The temperature sensors placed into the container at intervals make measurements during the regeneration and send data to the control unit. The control unit adjusts the position of the heater according to the data received from the temperature sensors. The control unit evaluates the data received from the temperature sensors at predetermined time intervals and directs the heater to the least hot region.
In another embodiment of the present invention, the heater is M-shaped. By means of this spaced structure, the movement of the heater in the horizontal direction in the container is provided to be more fluent.
In another embodiment of the present invention, the top side of the container is left empty. Thus, the desiccant material particles displace more easily while the heater moves in the container.
In another embodiment of the present invention, the movement mechanism is disposed in the container.
The desiccant material has reversible feature. Preferably zeolite is used as the desiccant material.
By means of the present invention, a homogeneous heat distribution is obtained in the container and almost all of the desiccant material particles are provided to be regenerated. Thus, total dehumidification capacity is preserved for the next dehumidifying step. Moreover, the heater is prevented from contacting the desiccant material particles in the same region throughout the regeneration and from making them lose their desiccation characteristics. This prevents the drying performance of the dishwasher from decreasing in long term.
The dishwasher realized in order to attain the aim of the present invention is illustrated in the attached figures, where:
Figure 1 – is the schematic view of the dishwasher of the present invention.
Figure 2 – is the sideways cross-sectional view of the dehumidifying unit and the movement mechanism.
Figure 3 – is the top cross-sectional view of the dehumidifying unit and the movement mechanism.
Figure 4 – is perspective view of the dehumidifying unit and the movement mechanism.
Figure 5 – is the rear view of the dehumidifying unit.
The elements illustrated in the figures are numbered as follows:

Dishwasher
Tub
Tub inlet
Tub outlet
Air channel
Fan
Dehumidifying unit
Desiccant material
Heater
Container
Inlet port
Outlet port
Movement mechanism
Opening
Sealing element
Temperature sensor
Control unit

The dishwasher (1) comprises a tub (2) wherein the washing process is performed, a tub inlet (3) providing air entrance into the tub (2), a tub outlet (4) providing the air in the tub (2) to be discharged, an air channel (5) located outside the tub (2), providing a closed air circuit between the tub outlet (4) and the tub inlet (3), a fan (6) disposed on the air channel (5) and providing the air in the tub (2) to be sucked and a dehumidifying unit (7) disposed on the air channel (5) (Figure 1).
The dehumidifying unit (7) comprises a desiccant material (8) adsorbing the air passing therethrough, a container (10) wherein the desiccant material (8) is disposed, at least one heater (9) used during the regeneration of the desiccant material (8), at least partially extending into the container (10) so as to be embedded into the desiccant material (8), an inlet port (11) providing the air coming from the air channel (5) to enter into the container (10) and an outlet port (12) providing the air in the container (10) to pass into the air channel (5) again (Figure 2, Figure 3, Figure 4).
In the drying step of the washing program, humid air in the tub (2) is sucked by means of the fan (6) to be received into the air channel (5). The air passing from the air channel (5) to the dehumidifying unit (7) by means of the inlet port (11) is adsorbed by the desiccant material (8) in the container (10) and heat is emanated. The air dehumidified and heated in the dehumidifying unit (7) leaves the dehumidifying unit (7) by passing through the outlet port (12) and returns to the tub (2) through the air channel (5). Thus, the air leaving the tub (2) as humid completes its closed cycle by returning to the tub (2) in a dry and hotter state. Thus, water remaining on the dishes after the rinsing step is removed.
The desiccant material (8) saturated with moisture in the drying step is regenerated in the next washing step by being heated by means of the heater (9) and regains its adsorbent characteristic.
The dishwasher (1) of the present invention comprises a movement mechanism (13) providing the desiccant material (8) to be stirred by moving the heater (9) in linear direction. The movement mechanism (13) is activated during the regeneration process. By means of the movement mechanism (13), the heater (9) plunged into the desiccant material (8) is moved inside the container (10) and the desiccant material (8) particles displace with the effect of this movement. Consequently, the desiccant material (8) particles close to the heater (9) are prevented from losing their desiccation characteristic by being continuously exposed to high temperatures and almost all of the desiccant material (8) particles in the container (10) are provided to be regenerated by the heater (9) also reaching the desiccant material (8) particles that are away from it. Thus, total dehumidification capacity and hence drying performance are preserved.
In an embodiment of the present invention, the heater (9) moves in the horizontal direction in the container (10). In this embodiment, the heater (9) moves back and forth along the container (10) between the inlet port (11) and the outlet port (12), thus providing the whole desiccant material (8) in the container (10) to be heated.
In another embodiment of the present invention, the dehumidifying unit (7) comprises at least one opening (14) disposed on the container (10) and providing a portion of the heater (9) to be taken out of the container (10) by being passed therethrough. The ends of the heater (9) are taken out of the container (10) through these openings (14) to be mounted to the movement mechanism (13) and move along the opening (14) during the regeneration (Figure 5).
In another embodiment of the present invention, the dehumidifying unit (7) comprises at least one sealing element (15) that prevents the desiccant material (8) from getting out of the container (10) by covering the gap between the opening (14) and the heater (9). The sealing element (15) prevents the desiccant material (8) particles displacing inside the container (10) from leaving the container (10). Moreover, the sealing element (15), by means of its flexible structure, prevents the movement of the heater (9) from being limited (Figure 5).
In an embodiment of the present invention, the dishwasher (1) comprises at least one temperature sensor (16) disposed in the container (10) and a control unit (17) that changes the position of the movement mechanism (13) according to the data received from the temperature sensor (16). In a version of this embodiment, the temperature sensors (16) are placed along the container (10) at intervals. The control unit (17) controls the data received from the temperature sensors (16) at certain time intervals and directs the heater (9) to the least hot region. Thus, a homogeneous heat distribution is provided in the container (10) and almost all of the desiccant material (8) particles are regenerated.
In another embodiment of the present invention, the heater (9) is in corrugated form. In this embodiment the heater (9) is preferably M-shaped. Thus, the desiccant material (8) particles are provided to be homogeneously heated along the vertical cross-sectional area of the container (10).
In another embodiment of the present invention, a portion of the container (10) is left empty in order to facilitate the movement of the desiccant material (8) particles. Thus, when the heater (9) starts moving, the desiccant material (8) particles can shift more easily, facilitating the movement of the heater (9).
In another embodiment of the present invention, the movement mechanism (13) is disposed in the container (10).
In another embodiment of the present invention, the heater (9) moves in the vertical direction in the container (10).
The desiccant material (8) has reversible feature. Preferably zeolite is used as the desiccant material (8).
By means of the present invention, the desiccant material (8) particles are prevented from burning and losing their desiccation characteristic during the regeneration of the desiccant material (8). Thus, drying efficiency of the dishwasher (1) is prevented from decreasing in long term. Furthermore, since a homogeneous heat distribution is provided in the container (10), almost all of the desiccant material (8) particles are provided to be regenerated. Thus, total dehumidification capacity in the next dehumidifying step increases and hence a more efficient drying is provided.
It is to be understood that the present invention is not limited to the embodiments disclosed above and a person skilled in the art can easily introduce different embodiments. These should be considered within the scope of the protection postulated by the claims of the present invention.

Claims

A dishwasher (1) comprising a tub (2) wherein the washing process is performed, a tub inlet (3) providing air entrance into the tub (2), a tub outlet (4) providing the air in the tub (2) to be discharged, an air channel (5) located outside the tub (2), providing a closed air circuit between the tub outlet (4) and the tub inlet (3), a fan (6) disposed on the air channel (5) and providing the air in the tub (2) to be sucked and a dehumidifying unit (7) disposed on the air channel (5), having a desiccant material (8) adsorbing the air passing therethrough, a container (10) wherein the desiccant material (8) is disposed, at least one heater (9) used during the regeneration of the desiccant material (8), at least partially extending into the container (10) so as to be embedded into the desiccant material (8), an inlet port (11) providing the air coming from the air channel (5) to enter into the container (10) and an outlet port (12) providing the air in the container (10) to pass into the air channel (5) again, characterized by a movement mechanism (13) providing the desiccant material (8) to be stirred by moving the heater (9) in linear direction.
A dishwasher (1) as in Claim 1, characterized by the heater (9) that moves in the horizontal direction in the container (10).
A dishwasher (1) as in Claim 1 or 2, characterized by the dehumidifying unit (7) comprising at least one opening (14) disposed on the container (10) and providing a portion of the heater (9) to be taken out of the container (10) by being passed therethrough.
A dishwasher (1) as in any one of the above claims, characterized by the dehumidifying unit (7) comprising at least one sealing element (15) that prevents the desiccant material (8) from getting out of the container (10) by covering the gap between the opening (14) and the heater (9).
A dishwasher (1) as in any one of the above claims, characterized by at least one temperature sensor (16) disposed in the container (10) and a control unit (17) that changes the position of the movement mechanism (13) according to the data received from the temperature sensor (16).
A dishwasher (1) as in any one of the above claims, characterized by the heater (9) in corrugated form.
A dishwasher (1) as in any one of the above claims, characterized by the container (10), a portion of which is left empty in order to facilitate the movement of the desiccant material (8) particles.