VAPOUR-CONDENSING DEVICE FOR A DISH-WASHER

Abstract: This invention relates to a device for a dish-washer comprising a tub (17) in which liquid is circulated for cleaning dish in the tub. The tub communicates with athmosphere via an open passage comprising a condensator chamber (12, 14) which is placed outside and at distance from the outer surface of the tub.

Description: This invention relates to a device for a dish-washer comprising a tub in which liquid is circulated for cleaning dish which is placed in the tub, according to the preamble of Claim 1. Such a device is known from DE-A-30 38 080 When using such machines it is desirable to pick out the dish from the machine completely dry. In order to dry the dish heat is supplied by means of a an element which is heated by electricity at the end of the dish-procedure. Thus, the moisture which is present in the tub is taken up by the warm air which is then vented to the ambient or condensated. By venting the air between the tub and an outer surrounding shell of the machine, which is a common method, there is however a risk for corrosion problems since the moisture condensates on different metal parts of the machine. If the vent passage ends outside the machine and the machine is placed open there is a risk for injuries because of the outflowing heat moisture saturated air. If, on the other hand, the vent passage is hidden in a built in arrangement outside the machine there is a risk for moisture precipitation on interior fittings and under the work top. It is also known to use separate interior means for condensating the water, see i.e. DE 1.962.049, FR 2.491.322 and GB 1.245.570. However these systems are rather complicated since there is a demand for water supply, pumps, fans and channel means for directing the flow of air to certain areas. Another condensation method which is very simple and used frequently is to allow the air to self-circulate in the tub which means that the water condensates on the cold tub walls. The condensate flows down from the walls and is collected in a sump at the bottom of the tub from which the water then is removed by activating the drain pump. It is however diffucult to keep the walls of the tub as cold as necessary since the tub normally is surrounded by a sound-absorbing layer which also works as a heat-insulation against the surrounding colder air. It is also common to use a combination of the methods mentioned above. Moreover if the machine is not equipped with a vent passage for the heated air the machine has to be provided with an opening towards atmosphere in order to equalize the overpressure which is created when the lid is moved to its closed position or when the water is heated. It is also a fact than in case the tub is made of plastic it is not possible to use too large power for the heating element during the drying phase since the heat could damage the material. In order to avoid the problems mentioned above it is, according to the present invention, suggested to use a simple and reliable device working as a pressure equalizer and according to the condensation model but not necessarily having a heat supply during the drying cycle and where cooling of the air is so effective that almost all moisture is precipitated as a condensate within the machine. This is achieved by an invention having the characteristics mentioned in claim 1. Further embodiments of the invention are defined in Claims 2 to 5 An embodiment of the invention will now be described with reference to the accompanying drawing where Fig. 1 is a partly cut vertical projection of the tub wall seen from the inside whereas Fig. 2 is a cut on the line II-II in Fig. 1, Fig. 3 is a diagrammatic front view of another embodiment of the invention with an associated lid open. In the Figures 10 is one of the vertical walls in the tub the wall having an opening through which a tube 11 is inserted. This tube is a part of a box 12 placed outside the tub the box at its upper part having three sleeves 13 on which three hoses 14 are fastened. The hoses 14 each have a U-shaped part which in the embodiment shown in Figure 1 and 2 have different radius of curvature so that they can be placed in the same vertical plane. Each hose also has an outlet opening 15 which is placed below the tube 11. The tube 11, box 12 as well as the hoses 14 are preferably made of plastic. The box 12 and the pipes 14 together form a condensation chamber. Also in the arrangement shown in Fig. 3 the box 12 is placed outside one of the vertical tub walls 10 the hoses 14 however being placed above the roof part 16 of the tub and continuing down between the outer cover 17 and the second side wall 18 of the tub so that the hoses end above the bottom plate 19 of the cover. The hoses 14 are preferably placed so that the largest possible length slopes towards the box 12. In order to take care of the few drops of water which could be the result of condensation in the end part of the hoses there is a plate of plastic or a small plastic container 20 below the openings 15 from which the water easily evaporates. The device operates in the following way. The heated dish-water in the tub during the dish-washing procedure transfers its heat to the walls of the tub and to the dish. When the dish-water is emptied the surrounding tub walls will first be cooled which means that the steam which is present in tub partly is precipitated as water drips on these walls the drips flowing down the walls and being collected in the sump at the bottom of the tub. Since the tub via the tube 11 is vented to the ambient a part of the heated moisture air will flow through the box 12 and further through the hoses 14 to outlet 15 from which it continues into the space between the tub and the outer cover 17 of the machine or to the surrounding interior fittings. When the air passes the box 12 and flows to the highest point of the hoses 14 the moisture will precipitate on the surrounding surfaces and return through the hoses 14 back to the box 12 from which it by means of the tube 11 is returned to the sump of the tub. The air which flows out through the openings 15 will thus be effectively dehumidified. Because the box as well as the pipes are placed at a distance from the wall of the tub the surfaces surrounding the flowing humid air will be cooled effectively by the ambient air. Thus by the suggested arrangement it is possible to compensate the loss of the cooling effect of the tub wall when increasing the sound insulation of the tub as well as it is possible to compensate a corresponding deterioration depending on a worse thermal conductivity if i.e. the tub is made of plastic instead of metal. It should be observed that a result of the drying procedure to a large extent is guided by the temperature of the final rinsing water. The higher temperature the better drying result. Even if this invention primarily is intended to be used without a following additional heating during the drying procedure it is of course possible to use said arrangement also in combination with such a drying procedure. It is also possible within the scope of the invention to vary the shape of the condensation chamber within wide limits i.e. by using another number of pipes or an integrated box and pipes an so on.

Claims: Device for a dish-washer comprising a tub in which liquid is circulated for cleaning dish in the tub, the tub communicating with atmosphere via an open passage, forming a condensation chamber (12, 14) which is placed outside and at a distance from the outer surface of the tub, characterized in that the chamber comprises one or several conduits (14) which at least partly are shaped as a U which is placed upside down, the conduit or conduits (14) being associated with a common box (12) or the like communicating with the tub. Device according to claims 1, characterized in that the conduit or conduits (14) extend along one of the vertical side walls (10) of the tub and open between the tub and a cover or the like surrounding the tub. Device according to claims 1, characterized in that at least one of the conduits (14) extend from one side wall (10) of the tub above the roof part (16) of the tub. Device according to claim 3, characterized in that the conduit (14) or conduits extends to the opposite side wall (18) of the tub. Device according to claim 4, characterized in that the conduit (14) or conduits continue down below the outside of the opposite side wall (18).

Inventors: DYGVE, HANS GUSTAV ELOF
Applicants: AKTIEBOLAGET ELECTROLUX
Application year: 1990
Main classification: A47L15
IPC codes: A47L15