A CONTINUOUS DISH-WASHING MACHINE

Abstract: The time control of the working procedure of a continuous dish-washer implies a saving of energy thanks to a dividing of the procedure into parts of treatment which only last as long as dish goods are treated. The parts of treatment are controlled by timers provided with control circuits and zero setting circuits for adjusting the time of operation, elimination of disturbances caused by interruptions, zero setting by the input of dish goods etc.

Description: A continuous dish- washing machine The present invention is related to a time control system for the workin process of a continuous dish-washer by which an essential saving of energy can b achieved. Tunnel dish-washers have a conveyor which carries the dish goods through plurality of zones in the longitudinal direction of the machine. It is piorly know to use devices at the conveyor to start and/or stopp the running of the machine a times when the goods is put into or taken out of the machine. If the running i occasionally interrupted or the function of the machine fails, the washing will b insufficient which is first discovered at the re-use of the goods. On the othe hand, the machine can still be running during periods when dish goods for som reason is not remaining in the machine which means losses of energy. By the wa of a more accurate control of the working process it is possible to eliminate suc drawbacks of the machine. By the invention the problem to - drive the machine in well determine intervals is solved without the influence of disturbances in the form of e.g. th opening of doors, a stop of the conveyor etc. At an input of goods a sensin member in the input end of the machine will start an electronic timer which onl counts the time when the machine is runnning and is put to zero as soon a another batch of goods comes into the input end. If no more goods will come th machine is stopped after a predetermined time period. In fact several of the zone in the machine are controlled by its own timer which reduces the use of energy to just the zone where, for the time being, dish goods are treated. The properties which thus make an improvement of the dish washer are more closely defined in the characterizing clause of Claim 1. An example of an embodiment of the invention is described in the following with references to the accompanying drawing which shows in Fig. 1 a vertical projection of a dish-washer according to the invention, Fig. 2 a wiring diagramme of an electronic timer in the dish-washer. In a continuous dish-washer there is a conveyor 10 for conveying dish goods on racks essentially horizontally through the machine. At the input end a pre-washing zone 11 begins having a tank 12 in the bottom and a circulation system 13. A drain 14 is provided in this zone through which exceeding liquid passes off. The next zone is the detergent washing zone 15 which has a separate f OMPI tank 16 and a circulation system 17. The next step is the post-washing zone 1 with a tank 19 having a drain 20 for exceeding liquid which is passed to th pre-washing zone. The tank 19 is a collecting tank for rinsing liquid from th finishing zone 21 which is the final rinse. The spraying system 22 in this zone i supplied via a heater 23 directly from the water mains and rinses then the good with clean, hot water. This is applicable to a three-tank embodiment of th machine. It may also be carried out as a two-tank embodiment which means tha the detergent washing zone and the post-washing zone are merged. After that rack has left the final rinse it is suitably passed to a roller conveyor where th dish goods are self-drying. For the control of the working procedure in the machine it is used a electronic timer according to the wiring diagramme of Fig. 2. The timer has i principle the following working mode. A switch 24 at the input of the machine makes a contact when it is actuate by a rack put into the machine and supplies a start signal on a wire 25 to the inpu of an inverter 26 (a Schmitt trigger) which conducts the inverted and into a rea pulse shape converted signal to a counter 27 which in this example is a standar module MC 14541 according to conventional TTL-technics. The properties of thi counter are important in that the counting speed (the pulse frequency) i externally controlled by an adjustable control circuit 28 and that the counter b an interruption in the control stops at a reached number and proceeds therefro when re-started after the interruption. The output 29 of the counter supplies signal during the time the counting proceeds up to a predetermined number an then the signal ceases. During the counting the signal is amplified by transistor 30 which supplies a control current to a relay 31 controlling a rela contact 32 which makes the conveyor start and switches in the driving circuit (not shown) of the first zones 11,15 and eventually 18 of the dish-washer. As th pulse frequency is adjustable (here by means of a potentiometer 33 in the contro circuit) the period of driving the machine can be synchronized with the conveyin speed of the rack so that the driving ceases at the moment when the rack leave the last zone of that part of the procedure which is controlled by the timer. The above-said interruptions may occur when someone opens a door of th machine or when the conveyor for some reason is blocked. Against i.a. thes events there are safety contacts 34 positioned in the machine. If any one of thos contacts is closed a zero signal is obtained on the output of the inverter 35 t which a number of diods 36 are connected. These dϊods will then short-circuit th control signals to the transistor and the counter. The effect of this short-circui will be that the counter stops on the number it has reached and the relay falls s that the driving circuits are broken and the goods is stopped. When the safet contact is re-opened the control signal is re-established so that the count proceeds counting from the reached number and the procedure goes on. During th interruption no part of the procedure is excluded as the rack and the spray syste stand still until the driving is taken up again. The control circuits for the final rinse are substantially identical with th now described device and make thus a doubling of the timer in the foregoing. I the diagramme we therefore use the same reference-numbers on the component as before but with the addition of a \ The relay contact 32' thus controls drivin circuits for the conveyor and the spray system 22. Of course, it is possible t complete the diagramme with another timer of the same kind as those two whic can control some separate part of the procedure. It may also be noted that th counter 27 has reset circuits which set the counter on zero, when another rack i put into the inlet end and actuates the switch 24. Thus another programme wil start every time a rack is put in independent of the fact that there are, or ar not, racks before in the machine. The saving of energy as mentioned in the introduction comes about by th sharing of the procedure into several zones, whereby the spray system in th respective zone is working only when dish goods are treated in the zone. As th energy losses contain deliberated moisture and heat conducted to a ventilatio device positioned on the machine, these losses are reduced when the several zone of the machine are used only in short intervals. Another advantage of this sharin of the procedure appears in a lower sound level thanks to the fact that the soun sources are fewer.

Claims: Claims _ 1. A continuous dish-washing machine having an inlet end, a conveyor and a outlet end and divided into zones of different treatment of dish goods an provided with a control device which starts the conveyor and driving circuits i the machine on actuation of a sensing member at the inlet end, character i z e d in that the control device is constituted of at least one electronic time (27) provided with a control circuit (28) and adjusting means (33) for the time o operation and a zero setting circuit which by actuation of the sensing member (24 sets the timer on zero. 2. A dish-washing machine according to Claim 1, charaterized in tha some zones in the machine are controlled by one timer and other zones b another. 3. A dish-washing machine according to Claim 1, characterized in that the time of operation is determined by the conveying speed so that th driving ceases when the goods leaves the last zone of the ones controlled by the timer. 4. A dish-washing machine according to Claim 1, characterized in that safety contacts (34) are disposed at doors and/or the conveyor and connected to the control circuit and the driving circuits in a wiring that stops the timer and the machine on actuation of such a contact and re -starts the same from where they stopped when the actuation of the contact ceases.

Inventors: ANDERSSON ANDERS JOHAN RUDOLF, BOREUS CLAES GOERAN, ERIKSSON GUNNAR GILBERT, ANDERSSON, ANDERS, JOHAN, RUDOLF, BOREUS, CLAES, GOERAN, ERIKSSON, GUNNAR, GILBERT
Applicants: ELECTROLUX AB, AKTIEBOLAGET ELECTROLUX
Application year: 1982
Main classification: A47L15
IPC codes: A47L15