GB2199675A

GB2199675A - Tableware washer control

Info

Publication number: GB2199675A
Application number: GB08730285A
Authority: GB
Inventors: Sang Kwon Kim
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 1986-12-31
Filing date: 1987-12-30
Publication date: 1988-07-13
Also published as: DE3744558A1; FR2609193A1; KR880007046A; GB8730285D0; KR910001073B1

Description

219967,5 1.

A CO M OL CIRCUIT FOR A TABLEWARE WASHER DESCRIPTION r .I The present invention relates to a control circuit for a tableware washer and more paticularly to a circuit which is designed not only to make it possible to dry tableware after being washed but also to prevent the malfunction of a microcomputer used as a system controller.

Recently, demand-for tableware washers has grown at a steady pace thanks to the improvement of living standards. These tableware washers are now required to function not merely as washers but also as driers.

In conventional tableware washers, it is difficult to produce the intended washing effect as these use a mechanical timer. Also, it is impossible to wash efectively in warm water they can not accurately control the temperature of the washing water.

Furthermore, these conventional tableware washers suffer from the disadvantages that they can not dry provided with drying tableware and that it is not only difficult for users to easily keep track 1 of the process in progress visually but also impossible for the users to adjust the washing time precisely in order to obtain the desired results.

It is an object of the present invention to provide an improved control circuit for a tableware washer aimed at allowing washers to dry as well as effectively wash tableware, making it possible to display the progress of each process visually.

It is another object of the present invention to provide a control circuit for a tableware washer aimed at preventing the microcomputer which is employed as the system controller from malfunctioning when the main power source is tur-ned on or off.

'Me present invention will now be described by way of illustrative example with reference to the accompanying drawings, in which; Figure 1 is a sectional view showing a tableware washer according to the present invention; Figure 2 is a perspective view of a tableware washer of Figure 1; Figure 3 is a schematic block diagram of the embodiment of the V cl present invention Figure 4 is a circuit diagram of the embodiment of Figure 3 Figure 5 is a waveform diagram useful for describing the operation of the initializer section of Figure 4 Figure 5 illustrates conventional initializer circiuts; and Figure 7 is a flow chart illustrating the operation of the micro- computer in the embodiment of Figure 3.

Referring to Figures 1 and 2, a tableware washer according to the present invention comprises a washing pump WP for washing table- ware, an impeller, a plate-rack, a water feeding valve V which controls water feeding into the washer, a draining pump DP for draining water to the outside and a heater H for heating up the water fed in by the water feeding valve V and also for drying the washed tableware.

Referring now to Figures 3 and 4, there is shown the preferred embodiment of the present invention.

1 t A microcomputer 1 performs all the processing or control of the system.

A usual power supply section 2 aupplies regulated DC voltage and current to the whole circuit.

An initializer section 3 is designed to prevent microcomputer malfunction when the power is first applied to the microcomputer 1 or when the power goes off.

A temperature detecting section 4 comprises a thermistor 'EH, resistors R 6 to R8 and an A/D converter. This section 4 heats up the washing water to a preset temperature (about 6TC) and keeps the temperature inside the washer stable during the drying of the tableware.

A driving section 5 comprises a relay RY for running the heater H, triacs T 1 to T 3 for driving the washing pump WP, the water feeding valve V and the draining pump DP and a buzzer BZ which gives a sound when each process is terminated of when any key in the key input section 7 inputs.

The door condition detecting section 6 detects whether the door 1 17 switch DR the washer is open or closed.

The key input section 7 includes keys for normal washing, strong washing, rinsing and drying.

Also, a pair of water level detecting switches ESW and a float switch FSW are included in the key input section 7.

A display section 8 displays visualIytheprocess selected by each key in the key input section 7.

One of the light-emitting diodes LEDl, to LED4 turns on while normal washing, strongwashing, rinsing or drying operation proceeds.

Also, one of the light-emitting diodes LED5 to LED8 turns on in is the same manner as the first four diodes LED1 to LED4 and displays the preset time during which each of the above-described operations proceeds.

In Figure, 4, R, to R30 are resistors, Qi to Q15 are transistors, W is a zener diode, D, to D6 are diodes, Cl to C9 are capacitors and 9 is a usual frequency detecting section.

1he operation of the embodiment described above is explained hereunder.

When the power is turned on for the first time DC voltage V1 is supplied to the microcomputer 1 by a usual power supply section 2 as shown in Figure 5. If a P-MOS (P Channel Metal Oxide Semiconductor)- type microcomputer is employed, it 1 is apt to malfunction unless its reset port (INIT) is kept at the high state for a given period of time (AT) until the voltage of its power input port (VCC) reaches a normal voltage level (VDD).

Also, when the power goes out, the reset port (INIT) of the P41OS-type microcomputer must be kept at the high state for given period of time T) beforehand.

Figure 6 illustrates three conventional initializer circuits for preventing malfuction of the microcomputer. The circuits have disadvantages that they are not only unable to produce a satisfactory effect due to errors in a zenor diode or a capacitor but are also unable to serve as a counter-measure against the malfunctioning of the microcomputer particularly when the main power is turned on/off repeatedly during a short period of time.

Referring again to Figure 4, input voltage V1 through the smoothing V, capacitor Cl is divided by resistors R2 and R3 in the initializer section 3 and the divided voltage V2 is inputted to the base of the transistor Q2 Ihus, the transistor Q2 turns on and the transistor Q3 conversely turns off causing its collector to be in the high state until the divided voltage V2 rises to the voltage level VDD + VQ2BE after the normal voltage VDD is applied to the power input port VCC of the microcomputer 1. When the divided voltage V2 becomes equal to the voltage VDD + VQ2BE under such a condition the transistor Q2 turns-6ff'y 'the transistor Q3 turns on and accordingly, the collector of the transistor Q37 which is connected to the reset port INIT of the microcomputer 1, goes to the low state. Thus, the microcomputer 1 is prevented from malfunctioning when power if first inputted. Also, the initial izer section 3 ofIthe present invention functions in the same manner as described hereinabove even when the power goes out.

After the microcomputer 1 is in the normal operating condition., it waits for key inputs from the key input section 7.

When a normal washing-or a strong washing key is selected, the microcomputer 1 functions as shown in the flowchart of Figure 7.

Firstly, the outputs 03 and 0 4 of the microcomputer 1 go to the high state and the triacs T 2 and T 3 are turned on. Thus, the water feeding valve V opens and feeds water into the washer and, at the same time, water within the washer is drained to the outside by the operation of the draining pump DP. This is to remove leftovers and water left in the washer before the washing of the tableware is carried out.

Next, depending on what process is selected, the microcomputer 1 will alter its performace. For instance, when a normal microcomputer 1 will alter its performan-ze. For instance, when a normal washing process is selected, the draining and the water feeding processes as above-described are carried out for a given period of time and the preset normal washing time(about 25 minutes) is started in the memory. Then, the draining comes to a stop by the turning of the output 04 of the microcomputer 1 to the low state through the water feeding still goes on. When the water fed into the washer gets to a certain level, the float switch FSW is closed making the input IN4 of the microcomputer 1 jump to the high state and accordingly, the output 03 thereof jumps to the low state. Thus, the water feeding valve V stops feeding water.

At this time, the output 02 OE the microcomputer 1 goes to the high state, the triac T1 is turned on and the washing pump WP is thereby made to operate and wash the tableware. Also the V output 01 of the microcomputer 1 goes to the high state or to the low state depending on the water temperature information inputted from the temperature detecting section 4. For instance, when the temperature of the washing water is below about 60% the output 01 of the microcomputer 1 goes to the high state, the relay RY is energized and the heater H is thereby started. When it is above 60% the heater H is made to cease to operation because the output 01 goes to the low state. The reason that the tableware is washed in warm waf?t-i;to-improve washing effectiveness.

After the washing time preset by the microcomputer 1 is completed, a rinsing process is carried out.

After the rinsing process, the outputs 01 to 04 of the microcom puter 1 to the low state and the heater H, the washing pump WP, the water feeding valve V and the draining pump DP in the driving section 5 are. all stopped for about two seconds. lhis is to make swirling water settle and to make subsequent draining smooth.

After the two seconds are over, the output 04 of the microcomputer 1 jumps to the high state, the triac T3 is made to turn on and the draining pump DP is thereby started. After the lapse of a given period of time for draining, the water feeding valve V opens enabling water feeding and draining to be performed to eliminate food waste and dirty water from the washer.

Next, the outputs 0 and 0 of the microcomputer 1 jump to the 4 low state and the water feeding and draining are made to stop, thus stopping any water turbulence. Thereafter, the water is drained out by the draining pump DP. After this draining is completed, the Output 03 Of the midrocomputer 1 jumps to the high state and water is fed into the washer until the float switch FSW is closed. When the float switch FSW is closed, the water feeding comes to an end and then a rinsing process in cold water is followed for a certain period of time preset by the microcomputer 1. At this juncture, the output 04 of the microcomputer 1 is kept at the high state and other outputs 01 to 0 3 at the low state.

Upon completion of the rinsing process in cold water, the draining, the water feeding and the water heating processes as the water is heated to about 60% the Output 02 Of the microcomputer 1 goes to the high state and the rinsing in warm water is performed for a period of time. After the rinsing is completed, the output 04 of the microcomputer 1 jumps to the high v r:

T- - ill - stateand the draining pump DP starts to operat e.

A drying process is followed after the whole rinsing process is completed. , At this time, the state of the output 01 of the microcomputer 1 is controlled depending on the input signal from the temperature detecting section 4. When the temperature in the washer is above 60% the heater H is turned off and, when it is below 60% the heater H is turned on resulting in that the temperature in the washer is kept a-t-'about-60'C.

Once the drying process for a given period of time is completed, all processed from washing to drying are brought to a close.

Meanwhile, a pain of water level detecting switches ESW act as safety switches to stop further water feeding when the float switch FSW is out of order during the water feeding process.

If the door is opened during the operation of the washer, the door switch DR is turned off and cuts off the power supplied to the heater H, the washing pump WP and the water feeding valve V,thereby avoiding danger to the user. Also, the door condition detecting section 6 outputs a high level signals to the micro- computer 1 enabling : to detect the door opening.

The frequency detecting section 9 is connected to the AC input line and outputs the square wave of 60Hz to the microcomputer 1 as the time control signal.

As described hereinabove, the present invention is designed not only to automatically carry out a complete washing and drying process with the user needing only-t-6--pxish-the key for normal- washing, strong washing, rinsing or drying but also to promote effective washing by the precise control of each process with the advantage of special characteristics to prevent the microcomputer from malfunctioning.

1

Claims

1. A control circuit for a tableware washer including a microcomputer as its controller, the circuit comprising a power source; an initializer means between said source and a reset port of said microcomputer; a temperature detecting means of the washing water during a washing or a rinsing process or of the inside ofsaid washer during a drying process a driving means connected to and receiving control signals from said microcomputer, said driving means including a relay for driving a heater, three triacs for driving a washing pump, a water feeding valve and a draining pump, and switching transistors which trigger said triacs and said relay; a key input means including keys for normal washing, strong washing, rinsing and drying processes a door condition detecting means which outputs a door open detecting signal to said microcomputer when a door is open during the operation of said washer; and 1 - 14 means for displaying visually a process selected by each key in said key input means.

2. A control circuit according to claim 1, wherein said initializer means includes divide resistors and two switching transistors which operate reversely to each other, the base of one of said transistors being connected to said divide resistors, the collector of the other of said transistors being connected to the reset port of said microcompuL-eY-.--'

3. A control circuit according to claim 1, wherein said temperature detecting means includes a therTnistor, divide resistors and a A/D converter for interfacing with said microcomputer.

4. A control circuit according to claim 1, wherein said driving means further includes a buzzer giving a sound when each process is terminated or when any key in said key input means inputs.

5. A control circuit according to claim 1, wherein said key input means further includes a float switch for controlling the water feeding and a pair of water level detecting switches acting as safety switches dien said float switch is out of order during the water feeding.

k j i - 1) -

6. A control circuit according to claim 1, wherein said means for displaying includes four light-emitting diodes to disply normal washing, strong washing, rinsing and drying processes and other four light-emitting diodes to display preset times for the completion of said normalwashing, strong washing, rinsing and drying processes respectively.

7. A dishwasher including a microcomputer as controller, and including: a power source; an initialiser means connected between said source and a reset port of said microcomputer temperature detecting means for detecting t"he temperature during a washing or rinsing process or of the inside of said washer during a drying process; driving means responsive to control signals from said microcomputer, and including means for driving a heater, and means for driving a washing pump, a water feeding valve and a draining pump, key input means including keys for selecting washing, and drying processes; and means for displaying visually a process selected by means of said key input means.

its

8. A control circuit for a tableware washer substantially as herein described with reference to Figures 1 to 5 and 7 of the accompanying drawings.

Published l9se at The Patent Office; State House. 6671 High Rolborn, London WC1R 4TP. FVrther copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by MWtiplex techniques ltd. St Mary Cray, Kent. Con. 1187.