DISHWASHER WITH ADDITIVE DISTRIBUTOR MEANS AND REGENERATION CIRCUIT FOR A WATER DECALCIFYING SYSTEM

Abstract: A first actuator (17) for additive distributor means (14) and a second actuator (13) for a regeneration circuit (9÷11) of a feed water decalcifying system (5, 8) are disposed in parallel and adapted to be connected to a power supply (8, 9) via a single switch (20) controlled by the program control unit (21) of the machine. The first and second actuators (17, 13) have different response times and are selectively operable by clos­ ing the switch (20) for periods of corresponding durations.

Description: The present invention relates to an automatic dishwasher, particularly of the domestic type comprising a program control unit and a liquid flow circuit for the regeneration of the feed water decalcifying system with a regeneration circuit including an electrically controlled actuator. Such a dishwasher is known from GB-B-1015 526, As generally known, the decalcifying system substantially comprises an ion-exchange resin decalcifyer and means for directing the water to be supplied to the washing tub therethrough. The decalcifyer has to be periodically regenerated by flushing it with a salt solution, and is to this purpose connected via a control valve to a salt container adapted to have a metered quantity of regenerating water supplied thereto. The supply of the detergent, the distribution of the gloss finish and the regeneration of the decalcifyer are carried out at different times and for different periods during the operating cycle of the dishwasher, which therefore requires different actuators controlled by the program control unit through associated control elements for actuating the different distributors and the regeneration valve in the proper manner. For reducing the number of actuators and thus improving the operational reliability it has been proposed to employ detergent and additive distributors of an integrated type, i.e. having a common support body and actuated by a single actuator, preferably of a construction as described in the patent application DE-A-3,304,037. In particular, a simple memory device enables such distributors to release a metered quantity of gloss finish only after a closure flap of a compartment adapted to house a metered dose of detergent has been previously opened. Even when employing a distributor of this type, the dishwasher has still to be provided with respective switches for the separate control of the actuators for actuating the distributor and for controlling the decalcifyer regeneration operation. It is an object of the present invention to provide a dishwasher of a simplified and reliable construction, in which a single control element is capable, in cooperation with a minimum number of actuators, of selectively controlling the supply of the detergent, the release of the additve substance and the regeneration of the feed water decalcifying system of the machine. According to the invention, this object is attained in a dishwasher comprising a program control unit, additive distributor means including at least a first electrically controlled actuator, and a feed water decalcifying system with a regeneration circuit including at least one second electrically controlled actuator, whereby said first and second actuators are disposed in parallel and adapted to be connected to an electric power supply via a single switch controlled by said program control unit so as to close for at least one relatively short additive distribution period and at least one relatively long period for the regeneration of said decalcifying system, said first and said second actuator having respective response times shorter and longer, respectively, than the duration of said relatively short period. By suitably programming the program control unit in a per se known manner it is thus possible to selectively control the actuators for the regeneration of the decalcifyer and for the distribution of the additive by the use of a single control element to thereby improve the operational reliability of the machine. The characteristics and advantages of the invention will become more clearly evident from the following description, given by way of example with reference to the accompanying drawing. The only figure of the drawing shows a diagrammatical illustration of a preferred embodiment of a dishwasher according to the invention, substantially comprising a dishwashing tub 1 having its bottom portion connected to a discharge pump 2 and a circulation pump 3 adapted to feed rotary spray arms 4. Tub 1 is connected to a water supply via a feed conduit 5 including a series of a supply valve 6, a free jet air gap 7 and a decalcifyer 8. The end portion of conduit 5 is preferably of a construction as described in the patent EP-B-0.022.911. The dishwasher is also provided with a flow circuit for the regeneration of the active substance of decalcifyer 8, substantially comprising a metering receptacle 9 and a container 10 for containing a salt or another regenerating substance. Receptacle 9 and free jet air gap 7 are preferably of a construction as described in GB-B-2,063,658; in particular, the bottom portion of receptacle 9 is connected to decalcifyer 8 via a regeneration conduit 11 in which salt container 10 and a valve 12 actuated by an electrically controlled actuator 13 are disposed in series. The dishwasher further comprises distributor means 14 disposed adjacent the loading door (not shown) for the supply of additive substances such as a detergent and a gloss finish. Distributor means 14 is preferably of a construction as described in the already named DE-A-3,304,037, and comprises a detergent compartment 15 provided with a closure flap, and a gloss finish compartment 16. The closure flap of compartment 15 is adapted to be opened by an actuator 17, for instance a solenoid or a thermistor device, in response to a short control pulse having a maximum duration of a few seconds. Additive compartment 16 is adapted to release a metered amount of gloss finish or the like under the control of actuator 17, but only when the latter receives a short control pulse after the closure flap of compartment 15 has already been opened. According to an aspect of the invention, actuators 13 and 17 are disposed in parallel and adapted to be connected to the terminals 18, 19 of an electric power supply via a single controlled switch 20, preferably of the electronic type, actuated by the program control unit 21 of the machine. Actuator 13 is of the delayed response type and may to this purpose be of a construction as described in Italian Patent Application No. 67994 A/80, filed on 23.01.1980 in the name of Libero Elettrotecnica S.n.c.. In particular, actuators 13 and 17 have respective response times longer and shorter, respectively, than the duration of the relatively short periods during which program control unit 21 causes switch 20 to close for actuating distributor means 14, as will become evident as the description proceeds. By suitably programming the operating times and periods of program control unit 21 in a per se known manner it is thus possible to preset the selective actuation of distributor means 14 and regeneration valve 12. Program control unit 21 of course controls all of the functional component of the machine in the conventional and therefore not decribed manner. Considering only the more significant phases of the operating cycle of the dishwasher, receptacle 9 contains a metered amount of regeneration water derived from conduit 5 after the immision of water to tub 1. At this time a washing phase may be initiated by actuating circulation pump 3 and closing switch 20 for a period of a few seconds. i.e. for a period shorter than the response time of actuator 13. This results in the actuation only of actuator 17, causing compartment 15 of distributor means 14 to be opened for releasing the detergent previously supplied thereto into tub 1. In a final phase of the operating cycle of the machine, program control unit 21 causes switch 20 to close again for a short period shorter than the response time of actuator 13 to thereby release a metered amount of gloss finish from compartment 16. Subsequently switch 20 is caused to close for a period of a few minutes, i.e. longer than the response time of actuator 13, to thereby cause the latter to open valve 12. The simultaneous energization of actuator 17 does not produce any result with respect to distributor means 14, as the latter has already been previously actuated. In the conventional manner the opening of valve 12 permits the water contained in receptacle 9 to flow by gravity along conduit 11 through salt container 10 and valve 12 and into decalcifyer 8 which is thereby regenerated. The closing times of the single switch 20 may of course be controlled by program control unit 21 in a different manner which is not part of the present invention. The regeneration phase may thus for instance be initiated at the beginning of the washing phase contemporaneously with the release of the detergent from distributor compartment 15. Alternatively the regeneration phase may be initiated contemporaneously with the release of the gloss finish from distributor compartment 16. In each case it is sufficient that at the preselected instant for actuating the respective distributor compartment 15 or 16, program control unit 21 causes switch 20 to close for a period longer than the response time of actuator 13, i.e. for a period permitting the latter to open regeneration valve 12. In any case the volume of water retained in receptacle 9 is suitably smaller than or equal to the volume of resin container 8 to thereby prevent any of the regeneration liquid from entering tub 1 during the regeneration phase, irrespective of when it occurs during the operating cycle of the machine. The described dishwasher may of course be modified in any suitable manner within the scope of the invention. Thus distributor compartments 15 and 16 may be separate from one another and each provided with a separate actuator 17 connected in parallel with the other actuators and having a suitable response time shorter than that of actuator 13.

Claims: A dishwasher comprising a program control unit (21), additive distributor means (14) including at least a first electrically controlled actuator (17), and a feed water decalcifying system with a regeneration circuit including at least one second electrically controlled actuator (13), whereby said first and second actuators (17, 13) are disposed in parallel and adapted to be connected to an electric power supply (18, 19) via a single switch (20) controlled by said program control unit (21) so as to close for at least one relatively short additive distribution period and at least one relatively long period for the regeneration of said decalcifying system (5, 8), said first and said second actuator (17, 13) having respective response times shorter and longer, respectively, than the duration of said relatively short period.

Inventors: MILOCCO, CLAUDIO
Applicants: INDUSTRIE ZANUSSI S.P.A.
Application year: 1987
Main classification: A47L15
IPC codes: A47L15