Unit for heating water in a dishwasher machine

Abstract: A unit for heating water in a dishwasher machine is described comprising at least one filter (3, 5) arranged on the bottom of a washing tank (2) of the dishwasher machine so as to collect and to filter the washing water contained in the tank (2), a tray (8) for collecting the filtered washing water, a suction conduit (11) that takes the washing water towards a recycle pump (12). The unit comprises a flat heating element (13) that is arranged in a way adjacent to the bottom of the tray (8) so as not to hinder the flow of the filtered washing water toward the suction conduit (11).

Description: The present invention refers to a unit for heating water in a dishwasher machine. Dishwashers currently in use are generally provided with devices for heating the washing water (see e.g. US 5 755 244 A, DE 1 984 4898 A). In some cases such heating devices comprise armored electric resistors that are positioned inside the washing tank and in particular on the bottom of the same, in order to be invested by the flow of the washing water before the same flows toward a collection tray arranged in the bottom zone of the washing tank; in this way such resistors can exert a better air or water heating function. Such heaters are activated both in the washing stage of the dishes as well as in the drying stage of the same. However such resistors capture dirty particles that by desiccating cause unpleasant odours and in addition, since they are arranged completely at sight, they can cause scorches to the users because of the residual temperature existing once the washing or drying stages of the dishes is completed. In addition the positioning of the resistors on the tank bottom hinders the flow of the washing water toward the collection tray of the washing water, thus forming sudden pressure changes in the flow of water and increasing the times of execution of the washing or drying stages. The electric resistor, which is usually of tubular type, can be affected by the surface attack of the calcareous substances thus presenting, after several washing stages, overheating problems in some parts that can lead to electric interruptions on the same resistor and therefore to a fast substitution. In view of the state of the art herein described, scope of the present invention is to provide a dishwasher machine which solves at least partially some of the aforesaid disadvantages. According to the present invention, such scope is reached by means of a dishwasher machine as defined in claim 1. Owing to the present invention it is possible to provide a unit for heating water in a dishwasher machine in which the heating element is arranged in a position not at sight and that does not interfere with the flow of the washing water but so that the washing water laps the heating element in order to obtain the maximum heating efficiency. In addition such heating element is arranged in such a way so as to make the access and the handling easy in case of repair or of substitution of the same . The characteristics and the advantages of the present invention will become evident from the following detailed description of an embodiment thereof, that is illustrated as a non-limiting example in the enclosed drawing, Figure 1, that is a schematic view of the heater according to the present invention. With reference to Figure 1a unit 1 for heating water in a dishwasher machine not entirely visible in said Figure is shown. Said unit 1 is arranged under the bottom 2 of a washing tank of the dishwasher and it comprises a filtering wall 3 arranged on the bottom part of washing tank and supported on borders of its tank bottom. Such filtering wall 3 has a hole 4 on its bottom part on the edge of which the upper ends of an cylindrical filter 5 open on top rest. Said filter 5 rests with its bottom on a tube 6 which is arranged horizontally and has a perpendicular end 7 inside the filter 5; in the tube 6 clean water that serves to clean the filter 5 flows. The filter 5 and the tube 6 are arranged inside a tray 8 suitable to collect the filtered washing water; the tube 6 is integral with a side wall 9 of the tray 8. The latter communicates with a discharge pump 10 and with a duct 11 that takes the water to a recycle pump 12. Both the discharge pump 10 as well as the duct 11 are connected with opposite side walls of the tray 8 which is connected on top with the tank bottom 2 of the washing tank of the dishwasher. On the bottom of the tray 8 a flat heating element 13 is arranged, which is made up of a support with a plate resistor inserted between silicone packings, and closed on the bottom by a flange 14. Such position of the heating element 13 allows the heating of the washing water when it flows towards the duct 11 that leads to the recycle pump 12, since great part of the washing water is forced to pass through a zone 15 where the washing water laps the heating element 13 and it gets heated. The position of the heating element 13 does not hinder the flow of the washing water towards the recycle pump 12 in any way; in addition, since the element 13 must heat the already filtered washing water, the possibility of the presence of unpleasant odours in the dishwasher due to the heating of debris by means of contact with the heating element diminishes. The positioning of the heating element 13 at a depth h with respect to the bottom part of a communication duct 20 between the tray 8 and the discharge pump 10, always guarantees the presence of a certain amount of water, even if minimum, on the bottom of the tray 8 and therefore in contact with the heating element 13. This prevents the latter both from reaching high temperatures as well as from the adhesion of dry debris on its surface. The heating element 13 is also easily reachable by means of the single opening of the flange 14 that facilitates the repair or substitution operations of the element 13. The position of the heating element 13 not at sight prevents possible scorches of the user. The heating element 13 can for instance be made up of an insulated steel plate with a resistance applied according to the known thick film technology.

Claims: Dishwasher machine comprising a first filter (3) arranged on the bottom of a washing tank (2) of said dishwasher machine so as to collect and to filter the washing water contained in said tank (2), a tray (8) for collecting the filtered washing water, a suction conduit (11) that takes said washing water towards a recycle pump (12), a flat heating element (13) that is arranged in a way adjacent to the bottom of said tray (8) so as not to hinder the flow of the filtered washing water towards said suction conduit (11), characterized by comprising a second filter (5) which is arranged within said tray (8) and it is supported by tubular means (6) in which the clean water that serves for cleaning the second filter (5) flows, said flat heating element (13) being arranged under said second filter (5). Dishwashine machine according to claim 1, characterized in that said flat heating element (13) comprises an electrical resistor. Diswashing machine according to claim 1, characterized in that said heating element (13) is arranged at a certain depth (h) with respect to a duct (20) for the communication between said tray (8) and a discharge pump (10) of the washing water, so as to always guarantee the presence of a certain amount of water on the bottom of said tray (8) and therefore in contact with said heating element (13).

Inventors: FUMAGALLI SILVANO, FUMAGALLI, SILVANO
Applicants: CANDY SPA, CANDY S.P.A.
Application year: 2001
Main classification: A47L15
IPC codes: A47L15