GB1603827A

GB1603827A - Washing machines

Info

Publication number: GB1603827A
Application number: GB21692/77A
Authority: GB
Original assignee: TI Domestic Appliances Ltd
Current assignee: TI Domestic Appliances Ltd
Priority date: 1977-05-23
Filing date: 1977-05-23
Publication date: 1981-12-02
Also published as: IT1115983B; DE2822077A1; IT7849498A0

Description

(54) IMPROVEMENTS IN OR RELATING TO WASHING MACHINES (71) T.I. DOMESTIC APPLIANCES LIMITED, a British Company, of Radiation House, North Circular Road, London, NW10 0JP, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to washing machines and has particular reference to domestic wash- ing machines of the fully automatic kind.

A conventional, fully-automatic domestic washing machine has an electromechanical control system able to control the machine and progress it through each of a number of different washing machine cycles or programs.

The user determines which program is to be followed and once the machine is set to that program it will automatically cycle through to the end thereof.

Some fully-automatic machines perform wash/rinse programs that is to say a program in which articles are subjected to one or more washes and one or more rinses. Other fullyautomatic machines perform wash/rinse/spin programs and in this case there is added one or more "spins" to the wash/rinse program just described. There are, of course, still other fully automatic machines which subject articles to a "tumble dry" after the "spin" just mentioned.

The present invention refers to all such machines which are herein classified as "washing machines".

In addition, it is known to provide the washing machine with some means of indicating to a user the stage in a selected program that the machine has reached. Some machines have a series of "indicators" which light up in turn as the machine enters the particular stage identified by one of the indicators. Other machines have a dial over which moves an indicator, for example a pointer on a control knob, which identifies the particular stage in the program reached by the machine.

However, in both cases, the indications are approximate only because they show merely that the machine has reached a particular stage in a program. Moreover, the user has to guess how much time must elapse before the machine will reach the end of the particular program.

The duration of some stages differs from program to program and, in any event, even if the user has become familiar with those durations there are other factors affecting the total duration of a program, the effect of which is not readily predictable. For example, water heating time depends upon inlet water temperature and this varies, filling times may also vary in dependence upon changes in inlet water pressure. Thus, for the reasons set forth, a user is normally unable to estimate even roughly what time must elapse before the machine reaches the end of the program through which it is working.

According to the present invention, a washing machine has a control system for progressing the machine automatically through a number of different selectable programs, and a visual display system, the control system being adapted to cause the display system to display numerically the time that must elapse before the machine reaches the end of the selected program and to decrement the displayed time in accordance with the progress of the machine through the selected program.

The control system may also receive an input or inputs which correct the program time if for some reason there is a departure from that time.

Thus, the washing machine may have a control system for progressing the machine automatically through a number of different, selectable programs, a sensing device responsive to a condition that affects the time required to progress the machine through a selected program, and a visual display system, the control system being adapted to cause the display system to display numerically a time that must elapse before the machine reaches the end of a selected program, the displayed time taking into account the sensed value of the condition, and to decrement the displayed time in accordance with the progress of the machine through the selected program.

The time displayed at the commencement of a program may be the time that the control unit has been preset or programmed to indicate for that particular program. The time will have been calculated on the assumption that, based on information received by the various sensing devices, each stage in the program will take a certain time or a calculated time is "written in" to the control unit. However, if a different heating time than that assumed is required to bring a volume of water taken into the machine to a desired temperature, or if a different time than is assumed is required to take water into the machine, the control system will take account of this and automatically correct the displayed time.

Accordingly, the washing machine may have a control system for progressing the machine automatically through a number of different, selectable programs, a sensing device responsive to the temperature of water entering the machine at the commencement of a program, and a visual display system, the control system being adapted to cause the display system to display numerically a time that must elapse before the machine reaches the end of a selected program, the displayed time taking into account the temperature of water entering the machine, and to decrement the displayed time in accordance with the progress of the machine through the selected program.

The heating time will depend upon the temperature of water entering the machine and upon the volume of water that has entered. The filling time will vary with water pressure and will depend upon the accurate operation of water level responsive means which control the intake of water.

In the case of those washing machines that incorporate a tumble dry sequence, the control system may control this sequence also. Further inputs to the control system will then include an indication of ambient temperature because this affects the duration of a tumble dry stage.

The control unit may also be programmed to respond to changes in voltage of the electrical supply system by which the machine is energised.

Changes in supply voltage will affect, inter alia, the time taken for water in the machine to be heated to the temperature required for a particular stage in a machine program.

By way of example only, an embodiment of the invention will now be described in greater detail with reference to the accompanying drawings in which: Figure 1 is a simplified, explanatory block schematic of the embodiment, Figure 2 is a more detailed schematic of the embodiment, and, Figure 3 is an explanatory flow chart.

The washing machine to which the control system is fitted is, itself, of a construction conventionally adopted for washing machines able to be cycled automatically through each of a number of washing programs any one of which can be selected at will by a user. The machine will, therefore, not be further described except where required to illustrate the functions of the control system.

The control system shown schematically in Figure 1 includes a microprocessor indicated by block 1 and programmed to respond to an input from each of a series of user control buttons 2. Each button 2 indicates a different program and actuation thereof initiates the indicated program.

The buttons may be of the so-called "touch" type which require a user simply to touch a desired button to initiate the program indicated by the button. Alternatively, a rotatable control knob may be provided for use in program selection, or, "push" buttons may be used.

The microprocessor is programmed, on receipt of an input from a program button to energise a digital display 3 to indicate the assumed time that the selected program will take. The display may indicate the time in minutes only or in hours and minutes.

As the machine progresses through the selected program, the microprocessor will correct the displayed time in a manner such that at any one instant after the correction has been completed, the displayed time is the time that must elapse before the machine reaches the end of the selected program.

The information received at first by the sensors or the predetermined time for a stage of the program may be such as to require the assumed time to be corrected in order for it to be an accurate time, and at an early stage in the program this correction is made.

In addition, the microprocessor may receive inputs indicating the commencement and end of certain stages whose time duration may vary in a manner unknown to the microprocessor and the user. For example, the time to fill may be different from the predetermined time assumed by the microprocessor, also where a program involves a water heating stage, the time taken to reach a requisite water temperature will depend upon the temperature of water flowing into the machine and thus the temperature of water in the tub at the end of the fill period. In such a case, the microprocessor is programmed to assume a particular time duration for a water heating stage which may be an assumption made that the water will be at a certain temperature at the end of the fill, or an assumption that the water will be at the temperature being sensed by the thermistor as soon as water starts entering the tub. On this assumption the microprocessor will make a forecast of the time it will take to heat the water to the wash temperature, based on a known rate of temperature rise for a particular amount of water drawn. In the event that the time required to carry out the water heating stage will be different from the assumed forecast time due to the temperature of the water in the tub after fill being different from the first assumed time, the microprocessor will make the appropriate correction to the displayed time as soon as the necessary correction has been determined.

The drawing shows that the microprocessor has three inputs. One represents fill time which will vary with inlet water temperature, the accuracy of water level responsive means and the program selected, another represents the temperature sensed by the sensing device, and the third the electrical supply voltage.

By way of example, for a particular program, the microprocessor is programmed on the assumption that the water in the tub at the end of the fill, will be at a temperature of 1 50C, but ti will be appreciated that it could equally well have been programmed to assume that the temperature would be the same as that being sensed at the start of or just before the fill, and that the fill time for wash is 4 minutes.

Other information in the microprocessor will relate to the program itself, thus a part of a particular program may be as follows:- main wash requires an intake of 25 litres of water which is then to be heated to 90 C. There then follows a wash, at that temperature, of duration 10 minutes after which there may be a top-up inflow of cold water. The water is then pumped out and the machine then cycles through a spin stage, a first fill rinse stage, an agitate stage, a pump out stage, a spin stage, a second fill rinse stage and so on. For such a program, the microprocessor will display a time of 110 minutes.

However, the machine may be connected to a cold and a hot water supply and at first the microprocessor may initiate the flow of hot water into the machine only. Thus, water inlet temperature will be 60"C and not 150C. This higher inlet temperature will be sensed by an appropriate device in the tub of the machine and the microprocessor will immediately operate the display to reduce the indicated time by an appropriate amount say 15 minutes.

The amount may flunctuate somewhat as the incoming water cools slightly on contact with cold parts of washing machine.

The fill time for a wash may be 3 minutes and not 4 as mentioned above and a correction will be made for this equal to one minute. By the time the appropriate volume of water has been admitted the display will have reached a steady figure having been corrected for incoming water temperature. The microprocessor will then know that there is a particular volume of water to be heated from somewhat below 60 C to 900C and that this should take 18 minutes.

However, if the supply voltage changes heating will take a different time. Another variable is the actual volume of water drawn in which may be different from that for which the microprocessor has been programmed because of an inaccurate water level responsive device. A different volume of water requires a different heating period.

At the end of the heating period, the time taken is 20 minutes instead of 18 as mentioned above. The microprocessor will then amend the time taken for the wash period from 10 minutes to 8 minutes so that the total time-to-run remaining will still be accurate.

The microprocessor may also receive further inputs indicating other stages whose duration may vary.

The digital display may comprise an array of light emitting diodes or a liquid crystal display, those being energised in the now well known manner.

Figure 2 shows the embodiment of Figure 1 in greater detail and there now follows a description of a simple program for a washing machine and of how the self-correction feature may be carried out in practice.

The microprocessor 1 is readily obtainable from manufacturers of such devices and will not be described further. The design is specifically related to the programming required so that the microprocessor will perform the logic functions required of it. The microprocessor will require input and output interfaces in order that instructions from various external sources may be fed into it and in order that its outputs can be translated into operations of switching devices such as relays etc. which can control the operating mechanical functions of the washing machine. The input and output interfaces are indicated at 4 and 5 respectively.

The design and manufacture of the interfaces is known and may include conventional momentary contact switches or touch sensitive switch controls on the input side and reed switches, triacs, with or without relays on the output side.

The output interface 5 receives signals from the microprocessor 1 which will control such functions as a water inlet solenoid on output 6, a water heater element on output 7, the machine motor in wash mode on output 8, the motor in spin mode on output 9, a drain pump on output 10 etc..

Signals from a water level switch responsive on input 11 and a water temperature sensing thermistor on input 12 as well as wash sequence selector switches on inputs 13, 14 and 15, and a start switch input 16 feed the input interface 4.

The interface 5 will also give an output signal to an LED digital display 3 giving the time of run in minutes of the sequence selected making certain assumptions that have been programmed into the microprocessors, e.g. that the time to fill will be, say 2 minutes, that the temperature of the water in the drum immediately after filling will be, say 400C, and that the rate of temperature rise during the heat up period will be say 2 per minute.

The microprocessor 1 will have programmed into it a time-base function with a look-up table with basic standard times for selected wash sequences which would be modified by addition or subtraction to compensate for errors actually occurring which are fed in from external sensing devices which will cause the digital display to reduce minute by minute.

This capability of comparing progress against the forecast will now be explained, as well as certain logic sequences, in the following simple example of a wash sequence. In this example, the sequence is: 1. Water inlet solenoid valve is energised and drum fills with water.

2. Water reaches the required level, water inlet solenoid valve is deenergised, wash motor is energised, and water heater is energised.

3. Water reaches the required temperature, water heater is switched off, but wash motor continues for further 10 minutes.

4. After 10 minute wash, motor is deenergised and drain pump motor is energised for 2 minutes.

5. After 2 minutes all water has been pumped out and machine is switched off.

To set the machine into operation, it may be first necessary to select the particular wash sequence required as above which may be for a wash at 94 C by making momentary contact of the appropriate sequence selector switch which provides an input on input 13 for instance. The signal transmitted to the interface 4 will cause the microprocessor to search immediately for the address of the appropriate sequence required in the look-up table with its standard sequence time. It may then be necessary to make momentary contact of a start switch which will transmit a signal on input 16 to the interface which will feed the necessary information to the microprocessor which will start the wash sequence and at the same time may cause the other sequence selector switches to become inoperative until the end of the sequence and this is well known in the art.

The microprocessor will now proceed on its selected logic program by sending out a signal to the output interface which will cause the water inlet solenoid valve to be energised and maintained energised until the microprocessor receives information via the water level switch on the machine via input 11 and the input interface 4 that the desired level has been reached, and the logic sequences will continue as described, including the fixed time periods of wash and pump out which will have been determined by the initial sequence selection, to the end of wash sequence selected.

On initiating the initial wash sequence the microprocessor will be programmed to make the assumption as described that the drum will take 2 minutes to fill and that the water temperature in the drum after filling will be 40"C and therefore the whole wash sequence will take the following time to complete: Fill = 2 minutes Heat water to 940C from 40 C = 54 C rise at 2 per minute = 27 minutes Wash at temperature = 10 minutes Pump out = 2 minutes TOTAL = 41 minutes This information will be transmitted to the digital display 3 and cause the corresponding numerals to be displayed.

Suppose, however, that the time to fill is, in fact, 3 minutes, the microprocessor time base will indicate that 2 minutes has elapsed and will now show 39 minutes run time, but the signal has not yet been received to confirm that the operation is completed and in this circumstance the microprocessor will 'hold' the figure of 39 minutes until the signal is received.

If, on the other hand, the time taken to fill is only 1 minute, the confirmation signal will be received by the microprocessor when the information the latter is transmitting to the digital display is to read 40 minutes. The microprocessor will have been programmed, however, to transmit the information to cause the digital display to read 39 minutes time to run when the confirmation of fill signal is received and therefore the display will jump to 39 minutes as soon as the fill signal is received. In other words, the signal from the water level indicator to say that the level has been reached is the logic impulse to tell the microprocessor the correct time to run (as far as it is confirmed at this stage): the signal overrides the time base logic impulse, either by holding until the signal from the water level indicator is received if filling takes longer than the time or jumping when the signal from the water level indicator is received if the filling takes shorter than the time.

Immediately the information is fed to the microprocessor that the selected water level has been reached, the microprocessor will transmit signals causing the water inlet solenoid valve to be deenergised and the water heater element and wash motor to be energised. The look-up table will contain the information that at this point in the sequence the impulse being received from the water temperature sensing device should be that the water temperature is 40 C.

However, it is possible that the temperature of the water supply was such that after allowing for the initial entry of cold water and the subsequent cooling in the tub during entry of hot water, that at the completion of filling the temperature is only 34cm. The time base in the look-up table will be impulsing information to show 39 minutes run time, which will be incorrect because in fact at the rate of temperature rise with which it is programmed, the time to heat to 94"C will be 42 minutes, this information overrides the time base and the time-to-run display will therefore be held at 39 minutes.

Conversely, if the temperature in the tub after filling is say 42 C then this information again overrides the time base and the time-torun display will be advanced by the microprocessor immediately to 38 minutes.

As already stated the early forecast before the water fill may be substantially inaccurate and a correction of many minutes might be required to correct the displayed time if the temperature after fill were substantially different from the temperature assumed by the microprocessor before the fill. However, washing machines are designed for either cold fill only, or for hot and cold fill. If the machine is for cold fill only, the look-up table may be programmed to make the assumption that the temperature after filling is say 1 5 C and that therefore the time to heat is accordingly longer and in this case the forecast will be substantially more accurate because the water temperature will not vary very much. If the machine is a hot and cold fill machine, water from the hot supply may be at approximately 600C in which case if the wash sequence required water at 400 it could happen particularly if the hot supply exceeded 60 C, that the temperature would be substantially above 400C if only hot water were drawn to the detriment of the wash itself.

It is possible by the judicious mixing of the correct amounts of hot and cold water respectively that the temperature of 40"C could be achieved almost exactly. It would be possible, to arrange the look-up information and programming of the microprocessor so that the information from the temperature sensing device were immediately instrumental in energising the cold and hot inlet water solenoid valves in order to achieve, as far as was possible, (i.e. to near the maximum of the hot inlet water temperature) the temperature required for the selected wash sequence. Such a machine would be capable of making very accurate forecasts immediately the fill was complete.

Furthermore, it would be possible for the microprocessor to be programmed so that if for instance a wash sequence temperature was required of 60"C and let us say that the hot supply were cold, this information could be passed almost immediately to the microprocessor which could make the adjustment to the forecast time-to-run almost as soon as water started to enter the machine.

It will, of course, be appreciated that the method of correction described is not limited only to the functions described and that wash sequences are normally more complicated requiring rinses and spinning for water extraction, but the principle as described applies also to more complicated sequences. Furthermore, the corrections need not be limited to impulses from sensing devices which monitor functions of the machine but also impulses indicating, for example variations in the voltage supply which will affect the time to heat the water and therefore possibly the total time to run. Also the time-to-run need not necessarily be modified in order to compensate for variations to the programmed forecast time in the look-up table if the initial water temperature were different to that to give the programmed heat-up-time.

It would be possible to reduce the wash time after the heat-up period by the amount that the heat up time exceeded the forecast. In this case the overall wash time would remain constant but that part of it at the finial temperature would be reduced. Another way that a correction could be made would be to increase or decrease the heat input of the heater element.

Figure 3 illustrates in the form of a flow chart the sequence of operations described above with reference to Figure 2.

WHAT WE CLAIM IS:- 1. A washing machine having a control system for progressing the machine automatically through a number of different selectable programs, and a visual display system, and in which the control system is adapted to cause the display system to display numerically the time that must elapse before the machine reaches the end of the selected program and to decrement the displayed time in accordance with the progress of the machine through the selected program.

2. A washing machine having a control system for progressing the machine automatically through a number of different, selectable programs, a sensing device responsive to a condition that affects the time required to progress the machine through a selected program, and a visual display system, and in which the control system is adapted to cause the display system to display numerically a time that must elapse before the machine reaches the end of a selected program, the displayed time taking into account the sensed value of the condition, and to decrement the displayed time in accordance with the progress of the machine through the selected program.

3. A washing machine having a control system for progressing the machine automatically through a number of different, selectable programs, a sensing device responsive to the temperature of water entering the machine at the commencement of a program, and a visual display system, and in which the control system is adapted to cause the display system to display numerically a time that must elapse before the machine reaches the end of a selected program, the displayed time taking into account the temperature of water entering the machine, and to decrement the displayed time in accordance with the progress of the machine through the selected program.

4. A machine as claimed in claim 2 in which the control system incorporates information indicating an approximate program time for each delectable program, and in which the control system is adapted to correct the approximate time to take account of the sensed value and to cause the display system to display the corrected time.

5. A machine as claimed in claim 3 in which the control system incorporates information indicating an approximate program time for each selectable program, and in which the control system is adapted to correct the approximate time to take account of the sensed temperature and to cause the display system to display the corrected time.

6. A machine as claimed in claim 1 and comprising a sensing device responsive to a condition affecting the implementation of a program, and in which the displayed time takes account of the sensed condition.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. programmed to make the assumption that the temperature after filling is say 1 5 C and that therefore the time to heat is accordingly longer and in this case the forecast will be substantially more accurate because the water temperature will not vary very much. If the machine is a hot and cold fill machine, water from the hot supply may be at approximately 600C in which case if the wash sequence required water at 400 it could happen particularly if the hot supply exceeded 60 C, that the temperature would be substantially above 400C if only hot water were drawn to the detriment of the wash itself. It is possible by the judicious mixing of the correct amounts of hot and cold water respectively that the temperature of 40"C could be achieved almost exactly. It would be possible, to arrange the look-up information and programming of the microprocessor so that the information from the temperature sensing device were immediately instrumental in energising the cold and hot inlet water solenoid valves in order to achieve, as far as was possible, (i.e. to near the maximum of the hot inlet water temperature) the temperature required for the selected wash sequence. Such a machine would be capable of making very accurate forecasts immediately the fill was complete. Furthermore, it would be possible for the microprocessor to be programmed so that if for instance a wash sequence temperature was required of 60"C and let us say that the hot supply were cold, this information could be passed almost immediately to the microprocessor which could make the adjustment to the forecast time-to-run almost as soon as water started to enter the machine. It will, of course, be appreciated that the method of correction described is not limited only to the functions described and that wash sequences are normally more complicated requiring rinses and spinning for water extraction, but the principle as described applies also to more complicated sequences. Furthermore, the corrections need not be limited to impulses from sensing devices which monitor functions of the machine but also impulses indicating, for example variations in the voltage supply which will affect the time to heat the water and therefore possibly the total time to run. Also the time-to-run need not necessarily be modified in order to compensate for variations to the programmed forecast time in the look-up table if the initial water temperature were different to that to give the programmed heat-up-time. It would be possible to reduce the wash time after the heat-up period by the amount that the heat up time exceeded the forecast. In this case the overall wash time would remain constant but that part of it at the finial temperature would be reduced. Another way that a correction could be made would be to increase or decrease the heat input of the heater element. Figure 3 illustrates in the form of a flow chart the sequence of operations described above with reference to Figure 2. WHAT WE CLAIM IS:-

1. A washing machine having a control system for progressing the machine automatically through a number of different selectable programs, and a visual display system, and in which the control system is adapted to cause the display system to display numerically the time that must elapse before the machine reaches the end of the selected program and to decrement the displayed time in accordance with the progress of the machine through the selected program.

7. A machine as claimed in claim 6 and

further comprising at least one sensing device responsive to an external condition affecting the program time, the or each said further device inputting to the control system, the latter being adapted to respond to each said input to correct the displayed time in accordance with the sensed condition.

8. A machine as claimed in any one of the preceding claims in which the displayed time is made up of times allotted for the implementation of each stage of a selected program, and in which the control system is adapted to adjust the time allotted to one or more stages when information is received by the control system indicating that there will otherwise be a departure from the displayed time, the displayed program time remaining unaffected by such adjustments.

9. A machine as claimed in claim 8 in which the control system is preset, for each selectable program, to display a time that is based on assumed times of implementation, and in which the control system is also adapted to adjust one or more of the assumed times on receipt of said information.

10. A machine as claimed in any one of the preceding claims and further comprising means for indicating to the control system the termination of a stage in a program, the completion time of which stage may vary, and in which the control system is adapted to adjust the time to be displayed in accordance with such indication.

11. A machine as claimed in claim 10 in which the control system operates, in respect of a stage the completion of which takes longer than an initially assessed time, to hold or increase the displayed time until the indication of termination is received.

12. A machine as claimed in claim 10 in which the control system operates, in respect of a stage the completion of which is effected in a time shorter than an initially assessed time, to cause the displayed time to change, on receipt of the termination indication, to take account of the shorter completion time.

13. A machine as claimed in claim 8 in which the control system is adapted, for each program, to cause the visual display system to display, when a particular program is selected, a predetermined time that must elapse before the machine reaches the end of the particular program, and in which the predetermined time is made up of times allotted for the implementation of each stage of the program, and in which the control system is also adapted to adjust the time allotted to a stage or stages or the conditions of implementation of a stage when information is received by the system indicating that there would otherwise be a departure from the displayed time, the adjustment being such that the displayed time remains unaffected by the change.

14. A washing machine substantially as herein described with reference to and as illustrated by Figure 1 or Figures 2 and 3 of the accompanying drawings.