GB2034927A

GB2034927A - Control apparatus for washing machines

Info

Publication number: GB2034927A
Application number: GB7935775A
Authority: GB
Original assignee: Industrie Zanussi SpA
Current assignee: Industrie Zanussi SpA
Priority date: 1978-10-19
Filing date: 1979-10-15
Publication date: 1980-06-11
Also published as: IT1108926B; DE2938536A1; IT7845729A0; ES485193A1; FR2439255A1

Abstract

A washing machine has a programmer 18 an inlet water valve 8, transducer arrangement 5, 51 for monitoring the amount of water being fed into the tub 7 and control apparatus 18 which controls the water valve so that for each phase of the selected operating cycle of the machine the optimum amount of water is admitted to the tub 7. The apparatus 18 may be implemented by a microprocessor and appropriately controls the valve 8 in accordance with various parameters including the amount of water as measured by the transducer arrangement, the nature of the current and previous operating phases of the machine, etc. <IMAGE>

Description

SPECIFICATION Control apparatus for washing machines The invention concerns apparatus for controlling the amount of water loaded into a clothes washing machine, whereby it is possible to optimise the amount of water which is loaded into the tub, in dependence on the various phases of the preselected cycle and the parameters relating to the jaundry (type of fabric, amount of laundry etc.).

At the present time, for the purposes of controlling the amount of water which is loaded into the tub of a clothes washing machine for domestic use in the various phases of the selected cycle of operation use is made of a pressure monitoring means or suitable devices for measuring the level of water which is loaded into the tub (for example electrical probes disposed at different heights).

In particular, controlling the level of water by means of a pressure monitoring means makes it possible to introduce water into the tub up to one or more predetermined levels which are established by the pressure monitoring means itself. Nonetheless, while still being widely used today, the pressure monitoring means suffers from well-known limits in regard to its accuracy and reliability.

Indeed, the operating point or range of the pressure monitoring means is variable either by virtue of the inherent calibration thereof (hysteresis) or by virtue of progressive ageing thereof. In addition, the pressure monitoring means may directly suffer from damage or trouble (for example contact sticking) or it may be indirectly influenced by relative movement between the pressure monitoring means and the tub, which movements are produced by the various mechanical components of the machine which act on the tub (suspension springs, weight of the ballast, etc.), as well as by the varying amount of water absorbed by the laundry.

Consequently, the amount of water introduced into the tub may vary in each phase of the cycle, relative to the amount of water desired. Even when the level of water introduced into the tub is controlled by means of other devices, for example level sensing means (electrical or optical) which are capable of detecting different levels of water in the tub, the same disadvantages as described above occur.

According to the present invention, there is provided apparatus for controlling the amount of water fed into a clothes washing machine, the machine having a programmer and at least one electrically operated valve for introducing the water, the apparatus comprising water metering means inserted into a supply conduit of the machine, and associated with a transducer, a main memory arranged to be controlled by the programmer and capable of providing information corresponding to the data relating to the various loads of water for the various phases of a preselected cycle of operation of the machine, and comparison means for comparing the information supplied by said memory and the information supplied by the transducer, said comparison means being provided with an output for controlling said electrically operated valve.

The present apparatus is particularly suitable for use in clothes washing machines which are provided with electronic programmers.

The invention will be better understood from the following description which is given by way of non-limitative example, with reference to the accompanying drawings wherein: Figure 1 shows a simplified block diagram of an embodiment of the apparatus according to the invention; Figure 2 shows a simplified block diagram of a second embodiment of the present invention.

Reference will first be made to Fig. 1 which shows a first emdodiment of the invention.

In particular, described below is the use of the apparatus according to the invention in a clothes washing machine provided with a known electronic programmer, such as that which is for example described in our British Patent Application No. 29835/78. Serial No.

2001454. For the purposes of simplification, the drawing does not show the block circuit diagrams relating to such a programmer; one is already described in the above-indicated Patent Application.

The control apparatus of the present invention comprises a water metering means 5 which is preferably of volumetric type, and which is inserted in the water supply conduit 6 and which is arranged to monitor the amount of water which is loaded into the tub 7 of the machine.

The water metering means is associated with a transducer 51 which is capable of generating digital electrical signals (pulses) in dependence on the quantity of water as detected by the measuring means. Simply by way of example, the water metering means.

Simply by way of example, the water metering means 5 may be constructed with a rotor which acts to measure the amount of water passing, and the transducer 51 may comprise at least two opposite magnetic poles which are mechanically connected to the rotor and which act as an electrical generator. In this case, the transducer is a small alternator; it will be seen therefore that the frequency of the electrical current induced in the magnetic poles is proportional to the number of revolutions of the rotor, and thus to the amount of water introduced per unit time.

For the purposes of the present invention, the metering means may be of any suitable construction, among those constructions which are already known from the state of the art, provided that it is always capable of producing a signal which can be converted to a digital signal representing the amount of water in the tub.

The water metering means 5 is hydraulically connected to at least one per se known electrically operated valve 8 and, by way of the transducer 51, drives a digital pulse counter which thus effectively integrates the signal from the transducer to produce digital outputs representing the amount of water in the tub.

The outputs of the counter 9 are in turn connected via a plurality of conductors to a first input 10 of a per se known digital comparator 11 whose other input 12 is connected by way of a plurality of conductors to a further pulse counter 13 which in turn is driven by a memory 14.

A control unit 15 which comprises the devices for manual selection of the parameters to be introduced into the electronic programmer for selecting the optimum washing cycles (as described in our above-mentioned Patent Application) is connected to the memory 14.

The output 16 of the comparator 11 is connected to the interface means 17 of the machine and thereby to the various operating members of the machine (electrically operated valve 8, main motor M, discharge pump PS, etc.).

In practical construction, the functions of the pulse counters 9 and 13, the comparator 11, the memory 14 and the interface means 17 will be carried out by a microprocessor 18 of per se known type.

The mode of operation of the above-indicated apparatus is based on the concept of monitoring the amount of water which is introduced into the tub by means of the above-described water metering means and knowing in advance the amount of water which the absorbed laundry is capable of retaining in dependence on some characteristic parameters such as the type of fabric to be washed, the amount of laundry loaded into the tub and whether the laundry is or is not likely to have been spun, etc.

It will thus be apparent that the amount of water introduced into the tub is related to the total amount of water introduced by way of the electrically operated valve (and measured by the water metering means) and any water which may already be contained in the laundry introduced.

For this purpose, it is necessary in the design phase to calculate the amounts of water which are contained in the soaked laundry and which related to the above-mentioned characteristic parameters and to the possible combinations thereof.

In addition it is necessary to calculate the optimum amounts of water introduced into the machine for each phase in each optimum washing cycle which the machine can carry out, in dependence on the parameters of the washing operation, which are selected by means of the control unit 15.

By arriving at the difference between the various data calculated as referred to hereinbefore, for every possible combination of the parameters of the laundry, the amounts of water which are to be introduced into the hub in each phase of each of the optimum washing cycles are obtained.

Such data are then stored in the memory 14 and will be used to determine the amounts of water which are effectively to be introduced into the tub in the varying phases of the preselected cycle. In practice therefore, in dependence on the varying washing parameters, the user operates the manual selection means which are contained in the control unit 15.

The programmer of the machine is arranged to perform the respective optimum washing cycle.

The memory 14 which contains the data in the above-described manner predetermines the optimum loads to be introduced in the various phases of the preselected cycle.

In this way, for each phase of the cycle in which it is necessary for water to be introduced into the tub, the memory 14 shows the amount of water that the electrically operated valve 8 will actually have to pass into the tub.

This value is expressed in the form of digital pulses which are applied to the comparator 11 by way of the pulse counter 13 which assumes a predetermined state. Then, by way of the interface means 17, the microprocessor 1 8 causes energisation of the electrically operated valve 8 so that water beings to flow into the machine.

The water metering means 5 then begins to measure the amount of water introduced and the associated digital pulses generated are progressively detected by the pulse cunting means 9 which passes such information to the comparator 11, in coded form.

The comparator 11 compares the coded information relating to the amount of water to be introdued into the tub, originating from the memory 14, to the information which is applied at input 10.

As long as the number of pulses detected by the pulse counter 9 is lower than the number of pulses which are passed to the pulse counter 13, the output 16 of the comparator 11 is at a given potential whereby the electrically operated valve 8 continues to pass water into the machine.

As soon as the desired amount of water has been introduced into the machine, the num ber of pulses detected by the pulse counter 9 is equal to the number of pules passed into the counter 13 whereby the output 16 of the comparator 11 changes state; in consequence, the electrically operated valve 8 is deenergised and the input of water into the machine is stopped.

As soon as discharge of the water is required, the microprocessor 18 actuates the discharge pump PS by way of the interface measn 17, in known manner.

Further amounts of water are introduced into the machine, in accordance with the above-described mode of operation.

If the transducer 15 is of analog type, a per se known analog-digital converter must be included in the circuit between the transducer 51 and the pulse counter 9.

A further possible alternative form is represented by using a known comparator 11 of analog type, in which case the transducer 51 would also be of analog type in order directly to drive the input 10 of the comparator 1 1, and in turn it would be necessary to replace the pulse counter 13 by a digital-analog converter for piloting the input 12 of the comparator 11.

Fig. 2 shows a different embodiment of the apparatus according to the invention, which also uses a second water metering means which is disposed in the discharge conduit of the washing machine.

This construction is not different in principle from that already described above with reference to Fig. 1, and it comprises a series of components which are the same as in the above-described embodiment, so that the same reference numerals are used therefor.

The circuit in Fig. 2 also comprises a water metering means 5 on the water supply conduit 6, which is connected to the tub 7 of the machine by way of at least one electrically operated valve 8.

The metering means 5 is associated with a transducer 51 which is connected to a digital pulse counting means 9 which pilots the input 10 of the comparator 1 1.

Provided on the discharge conduit 19, in addition to the discharge pump PS, is a second water metering means 20 which is similar to the metering means 5 and which is also associated with a transducer 21 similar to the transducer 51.

The transducer 51 drives a digital pulse counter 22, with coded signals corresponding to the amounts of water which are discharged in the various phases of the washing cycles, as detected by the metering means 20.

By way of a plurality of conductors, the output of the counter 22 is delivered to an auxiliary memory 23 which is arranged to store the information relating to the amounts of water which are discharged and which is arranged to transmit said information to its output under the control of the microprocessor 18 in which the memory is suitably incoporated.

The output of the auxiliary memory 23 is delivered to a first input 24 of a subtractor 25 whose second input 26 receives the output of the main memory 27.

The memory 27 which is controlled by the control unit 15 in a manner similar to the memory 14 in Fig. 1 is provided with a second output connected to a first input 28 of a second subtractor 29 whose second input 30 is connected to the output of the first substractor 25.

The output of the subtractor 29 in turn is connected to the input 12 of the comparator 11.

The information which is applied to the input 26 in a given operating phase of the machine represents the optimum amount of water required in the tub in the immediately preceding operating phase.

The information which is applied to the input 28 in the same operating phase represents the optimum amount of water required in the tube in the same phase.

For the purposes of the operations carried out by the subtractors 25 and 29, the signal at the input 30 represents the amount of water which has remained in the tub after discharge in the preceding operating phase, while the signal at the input 12 represents the amount of water which is effectively to be introduced into the tub, in order for the tub to have the optimum amount required in the actual operating phase.

The mode of operation of the apparatus is generally similar to that described above with reference to the Fig. 1 construction, as regards the result of accurately controlling the water-input electrically operated valve 8, by way of the interface means 17.

Nevertheless, calculation of the optimum amounts of water required for the various phases of the cycle of the machine is effected from time to time on the basis of direct measurements compared to absolute data stored in the memory 27.

In this way, it is possible to avoid the error, albeit negligible, which is due to the necessity of producing and storing in the memory 14 in Fig. 1, statistical data obtained by extrapolation at the design stage of the machine.

It will be appreciated that the modified embodiment of Fig. 2 could also be adapted for use with various types of components, as already indicated above with regard to possible alternative forms of the circuit of Fig. 1.

The present control apparatus thus makes it possible to determine the amount of water which actually has to be introduced into the tub, in dependence on the various characteristics (type, quantity and with/without spin) of the laundry to be washed.

Thus, the optimum washing cycle is effected each time, and the amounts of water which are strictly required are introduced into the machine, with a consequent saving of water, electrical power and detergent, the whole operation being controlled in a reliable and precise manner by the present apparatus.

In conclusion, it should be pointed out that the present control apparatus may also be embodied in electrical and/or mechanical forms, for example by replacing the memory, the control unit, the subtractor, the comparator and the interface means by equivalent per se known electrical and/or mechanical components which perform substantially the same functions. Consequently, it will be appreciated that the present invention is not limited solely to the control apparatus in its electronic form, but also covers possible electromechanical, pneumatic and other equivalent forms, in which the amount of water introduced into the machine is determined on the basis of data and/or measurements of volumetric values.

Claims

1. Apparatus for controlling the amount of water fed into a clothes washing machine, the machine having a programmer and at least one electrically operated valve for introducing the water, the apparatus comprising water metering means inserted into a supply conduit of the machine, and associated with a transducer, a main memory arranged to be controlled by the programmer and capable of providing information corresponding to the data relating to the varius loads of water for the various phases of a preselected cycle of operation of the machine, and comparison means for comparing the information supplied by said memory and the information supplied by the transducer, said comparison means being provided with an output for controlling said electrically operated valve.

2. Apparatus according to claim 1 wherein the transducer and the memory are capable of supplying digital information and are connected to said comparison means via respective pulse counters.

3. Apparatus according to claim 1 or 2 wherein the memory contains data corresponding to the difference between the optimum amount of water for the various phases of each washing cycle and the amount of water which can be absorbed by various types and quantities of laundry, control means being provided for enabling said memory selectively to supply said data to said comparison means.

4. Apparatus according to claim 1 and comprising a second water metering means in a discharge conduit of the machine and associated with a second transducer, an auxiliary memory arranged to be controlled by the programmer and capable of supplying information originating from said second transducer and relating to the quantities of water discharged in the various operating phases, and differencing means for receiving the information from said main memory and said auxiliary memory and for processing same for providing a signal to said comparison means.

5. Apparatus according to claim 4 wherein the main memory is capable of supplying as a first output information relating to the amounts of water required in the tub in the preceding operating phase and as a second output, information relating to the amounts of water required in a current operating phase.

6. Apparatus according to claim 5 wherein the differencing means comprise a first differencing stage which is arranged to receive information originating from said auxiliary memory and the first output of the main memory, and a second differencing stage which is arranged to receive the output of said first stage and the second output of the main memory, the output of said second stage being capable of supplying a signal to comparison means.

7. Apparatus for controlling the amount of water fed into a washing machine, such apparatus being constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

8. A washing machine incorporating apparatus according to any one of the preceding claims.