GB2051413A

GB2051413A - Washing machine

Info

Publication number: GB2051413A
Application number: GB8017652A
Authority: GB
Original assignee: Licentia Patent Verwaltungs GmbH
Current assignee: Licentia Patent Verwaltungs GmbH
Priority date: 1979-05-30
Filing date: 1980-05-29
Publication date: 1981-01-14
Also published as: DE2921911C2; GB2051413B; IT8022401A0; IT1130687B; FR2457921A1; DE2921911A1

Abstract

An automatic washing machine has a measuring device for detecting either the volume or weight of water needed to fill a washing chamber of the machine to a predetermined level and determining in dependence thereon the quantity of washing agent to be used and in conjunction with a programme unit, the number of the rinsing operations to be performed. A more absorbent load of washing is therefore supplied with more detergent and given more rinses than a less absorbent load. The quantity of detergent may be indicated to an operator or provided automatically by the machine from a reservoir.

Description

SPECIFICATION Washing machine The present invention relates to a washing machine and has particular reference to control means for such a machine.

In German (Fed. Rep.) patent specification No. 27 53241 there is disclosed a device for the metered discharge of a liquid detergent product into a water flow used in a washing machine, wherein to achieve optimum concentrations the quantity of agent to be added should be in a specific ratio to the quantity of water. The known device is equipped with a pump for the metered supply of the detergent product. An electronic control system can be provided for counting the number of strokes of the pump piston and for stopping the pump when a predetermined number of strokes has been carried out.

Furthermore, in German (Fed. Rep.) patent specification No. 2832216 there is disclosed an electronic programme control for washing machines into which various parameters at selector devices are fed before the start of the programme. Thus, amongst others, parameters such as the type of wash, the quantity of wash, the degree of dirt in the wash and the hardness of the water can be fed in. The front panel of the washing machine includes a pull-out washing agent container with separate compartments, an indicator element for the pre-wash agent and an indicator element for the main wash agent. The two indicator elements provide single-digit indications. Lighting up of the elements indicates the quantities of washing agent to be fed into the relevant compartments of the washing agent container for the pre-wash and the main wash respectively.This washing agent quantity is preferably characterised by the numeral visible on the corresponding indicator element, which states how often a suitable measuring cup, filled with washing agent should be emptied into the relevant compartment of the washing agent container.

In conventional automatic washing machines, the programme squences are fixed in advance and relate, like the instructions for the amounts of washing agent to be used, to maximum loading of the machine with, for instance, 4 or 5 kg dry weight of wash articles. The quantity of water introduced into the washing machine drum is, by constrast, variable, since it is established by a measurement of the filled level. This has the effect that, for the purpose of obtaining constant filled levels, in addition to the minimum quantity of water (reaching the filled level mark with the machine unloaded), according to the quantity and nature (especially absorption capacity) of the articles to be washed, an additional quantity of water adapted thereto is automatically introduced to serve for wetting of the articles to be washed.This additional quantity of water necessary for wetting the wash is termed "linked wash liquor According to the present invention there is provided an automatic washing machine cyclically operable to perform a number of washing and rinsing operations in each cycle, the machine comprising program control means for controlling the number of rinsing operations performed in each cycle, measuring means for measuring the quantity of inflowing water required to fill a washing chamber of the machine to a predetermined level and for providing a control signal having a value indicative of such measured quantity, and evaluating means for comparing the value of such control signal with predetermined values and determining in dependence on the comparison result preferred values for the quantity of a washing agent to be supplied to and the number of rinsing operations to be performed by the machine.

With a machine embodying the invention, optimum washing conditions are always obtained by a correct metering of the washing agent, so as to avoid adverse washing results due to insufficient usage of washing agent, which oblige a second rinsing operation and also unnecessary consumption of the washing agent and consequent damage to fabrics. Similarly, the rinsing operations following the washing operations are reduced to the minimum number required, resulting in savings in water, energy and washing time. At the same time, due to the rationed quantity of tenside- and phosphate-containing discharge water, pollution of the environment is reduced.

For obtaining a constant water level, the following quantities of water introduced automatically into a washing machine, for example as a function of the dry weight of articles of the same type, have been established.

water quantity introduced Total quantity for quantity of washing Dry weight achieving "stand- Portion of quantity agent for constant of wash ard level" for wetting wash concentration of 8 g/l o kg 11 1 88 g 1 kg 141 31 112 9 2 kg 17 1 61 136 g 3kg 21 1 101 168 g 4 kg 24 1 13 1 192 g From this it follows that when such a washing machine (without additional equipment) is used, the concentration relationships-whether related to the weight or to the volume of the washing agent the washing solutions used (e.g. constant 8 g/l or 15 ml/l) can hardly be reproduced, as it is almost impossible to estimate the quantity of washing agent to be fed in for each particular application.

Other possibilities of variation in respect of the quantities of water introduced are given by the filled levels, e.g. low level, normal level and high level of the known automatic washing machines, that can be selected directly by the user or are determined by the washing programme. In a machine embodying the invention, the fundamental difference between the possible filled levels lies in the fact that-if the low water level is selected-the quantity of water introduced over and above the minimum quantity serves essentially only for wetting the particular articles to be washed, whereas when the normal or high level is selected the wash is not merely wetted but is more or less completely submerged in the wash liquor.The result is that for a desired constant concentration of washing agent (e.g. 8 g/l or 1 5 ml/l) the absolute value of the entire introduced quantity of water is the determining factor, whereas the necessary number of the rinsing operations depends upon the quantity and the nature of the wash, which is characterised by the quantity of water necessary for wetting the wash, the so-called linked wash liquor. The value of the linked wash liquor can be represented with sufficient accuracy by the quantity of water necessary for reaching the low level, plus a constant which corresponds to the quantity of water for reaching the low level when the machine is empty.

The quantity of water flowing into the wash tank of the washing machine until the set level is reached can be measured, for example, by means of a water meter. The measurement cannot be completed, however, until a certain time after the washing machine has come into operation, since until the wash is completed saturated the water that has reached the filled level will gradually fall again in level and topping up again to the set level has to be repeated. After the final reading has been taken, the quantity of washing agent to be added can be calculated in suitable devices in the machine by multiplying by one of a number of stored metering instructions. The metering instructions stored in the machine (e.g. 8 g/l or 15 ml/l) are adapted at least to individual water hardness ranges.A value corresponding to the quantity of filling water could be obtained by other means, however, for example by measuring the increase in weight or the inertia of the drum.

The succeeding addition of washing agent-in liquid or solid form-is carried out either automatically, for example from a storage vessel incorporated in the machine, or else the user is requested. for example by means of an indication such a a light-emitting diode, to place the calculated quantity (e.g. "50 g" or "1 /2 a cup") of washing agent in the feed chamber. Where the introduction is manual the washing agent is, for example, flushed in subsequently. With manual metering, all the additives to be used for this washing programme sequence are indicated simultaneously. They must then be stored, as in conventional automatic washing machines, in corresponding feed chambers provided for this purpose.The quantity of washing agent necessary for the main washing operation is either indentical to that for the pre-wash or it is in a fixed, predetermined ratio thereto. With automatic metering, the feed of washing agent is carried out on the basis of a weight metering instruction (e.g. 8 g/l) or a volume metering instruction (e.g. 15 ml/l) in accordance with the quantity of water introduced. The feeding of the solid or liquid washing agent is carried out by means of appropriate metering devices, whereby solid or liquid washing agents can either be stored in any desired storage manner or can be supplied in prepared form, such as portioned or in sachets. A solid washing agent can, of course, be in pelletized form.

The number of rinsing operations to be carried out in a washing programme can be established from experiments, with only an acceptable amount of washing agent residue being permitted to remain in the wash after these rinsing operations. Such washing experiments, with different types of wash, quantities of wash and mixtures, provide values about the number of rinsing operations necessary for a washing agent concentration which is constant but adapted to the water hardness, in order to satisfy specific requirements in respect of permitted washing agent residues. These values are plotted against the relevant quantities of water necessary for wetting the wash and for the low level, a fixed relationship being found between the absorption capacity and the clear washing (rinsing) performance of the wash, as shown in Fig. 1.

Consequently, for washed articles having an absorption capacity of O to 4 I water two rinsing operations, from 4 to 8 I three rinsing operations, from 8 to 12 four rinsing operations and from 12 to 16 I five rinsing operations are necessary.

Since in a machine embodying the invention, a continuous determination and evaluation of washing agent concentration is intentionally dispensed with, it is only necessary, for instance, to start from an always constant, optimum concentration of washing agent for each hardness range. This has a positive beneficial effect, beyond this application, upon the entire washing process. Changes in the quantity of wash articles fed into the drum and in the type of articles have an effect upon the so-called linked wash liquor, i.e. the type and quantity of articles are characterised by the quantity of water absorbed by the articles. This quantity of water can be associated with a specific number of rinsing operations.The determining factor for the control of the rinsing operations, although independent of the selected water level, is only the additional water absorption required as a function of the wash articles for reaching the low water level, since it alone is a measure of the quantity and nature of the articles to be washed and thus a parameter for the number of washing operations. The values obtained for the number of washing operations show, for a constant and sufficient concentration of washing agent, differences ranging from two washing operations up to the hitherto conventional five rinsing operations.

As the table below shows, with properly adapted metering guidelines-independently of the prevailing water hardness constant number of rinsing operations is obtained for a specific type of article to be washed. The stated values are stored in the washing machine, so that as soon as the relevant reading is available, the number of necessary rinsing operations can be automatically determined by comparison and then fed to the washing programme.

The number of the necessary rinsing operations as a function of the water hardness for various types of wash articles and quantities of articles for a given metering are as follows: Number of necessary rinsing operations 1 kg wash 2 kg wash Type Hardness range Hardness range of wash I Il Ill IV I II Ill IV Frotte 2 2 2 2 3 3 3 3 (cotton) Half-linen 2 2 2 2 3 (2)3 3 2 Shirts 2 2 2 2 2 2 2 2 (cotton /synthetic 50/50) Synthetics 2 2 2 2 3 3 3 3 3 kg wash 4 kg wash Frotte 4 4 4 4 5 5 5 5 (cotton) Half-linen 3 3 3 3 4 4 4 (3)4 Shirts 3 3 (2)3 2 3 3 3 3 (cotton / synthetic) Hardness range Hardness of water Metering instruction 0-7 'dH 7 g/l II > 7-14 dH 8 g/l Ill > 14-21 dH 9 g/l IV > 21 dH 10 g/l The determining of the value of the linked wash liquor can be carried out either at the commencement of a washing process or-in order to reduce the time for the programme sequencc at a later stage particularly in the case of weight or inertia measurements. In the case of weight measurement, for example, the reading for the linked wash liquor can be obtained from the difference between the weight of the wash drum filled with dry articles (which is determined and stored at the start of the washing operation) and of the drum filled with wet articles, for example after the wash liquor has been pumped out after the pre-wash or main wash.The evaluating of the reading is carried out either in the sense of a possible reduction of the number of rinsing operations while retaining the water level hitherto used for washing, or for a constant number of rinsing operations with the quantity of water used for washing being varied by a variable water level adapted to the reading. It is also possible, by setting down the limiting parameters, to combine both methods of operation.

Embodiments of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Figure 1 is a diagram showing the relationships between the number of washing operations and quantities of water required to reach a predetermined filling level of the washing chamber of a washing machine, Figure 2 is a schematic diagram of control means in a washing machine according to a first embodiment of the invention, and Figure 3 is a schematic diagram of control means in a washing machine according to a second embodiment of the invention.

Referring now to Fig. 2 there is shown a washing machine control circuit for controlling the number of rinsing operations to be performed by the machine and quantity of washing agent to be used by the machine. The circuit comprises a switch 1 to switch on the machine and thereby energise a solenoid-operated valve 2 for the supply of water via a low level switch 3. This permits supply of the water via a water meter 4, to the wash tank of the washing machine. The water meter 4 measures the quantity of water necessary for reaching a predetermined low level in the tank and actuates a pulse transmitter to supply, according to the quantity of water that flows into the wash tank, a number of pulses per litre of water to a 'metering" evaluation circuit 6 and a "washing" evaluation circuit 7.

Simultaneously with the actuating of the switch 1, a timing device 5 is brought into operation. The device 5 delays transmission of the reading for the introduced quantity of water from the circuits 6 and 7 to, respectively, a washing agent quantity meter or indicator 8 and a washing operation program control unit 9. This delay is automatically provided to ensure complete wetting of the wash up to the point where no further topping up is necessary to maintain filling at the predetermined low level. After expiry of the time delay provided by the timing device 5, the measured result is then transmitted from the evaluation circuits 6 and 7 to the indicator or meter-which may be a flushing-in feed device-8 for the addition of the washing agent and to the program control unit 9 for carrying out the rinsing operations.

In Fig. 3 there is shown a control circuit for a machine with controllable filling to a normal or high level. In this case, a distinction must be made between reaching the low level, which is used to determine the control of the rinsing operations, and reaching the normal or high level, which is responsible for correct metering of washing agent. When the switch 1 is actuated, the solenoid valve 2 is energized via the low level switch 3 and also via a normal or high level switch 10, so that the water supply is effected through the water meter 4. The water meter 4 measures the quantity of water required until the set lower level is attained and actuates a pulse transmitter to supply, corresponding to the quantity of water flowing into the wash tank, a number pulses per litre of water to the evaluation circuits 6 and 7.

On actuation of the switch 1, the timing device 5 is simultaneously brought into operation, which delays the transmission of the reading for the quantity of water introduced into the wash tank to the meter or indicator 8 and to the programme control unit 9, so that a delay is automatically provided to allow for complete saturation of the wash articles when no further feed of water is necessary.

After the expiry of the time delay provided by the timing device 5, the measured result is then transmitted only from the evaluation circuit 7 to the programme control unit 9. Simultaneously, the timing device 5 bypasses the switch 3 and energizes the valve 2 via the switch 10, so that the water supply to the washing machine is resumed. Corresponding to the total quantity of water introduced into the washing machine, all the pulses emitted by the pulse transmitter are now transmitted only to the circuit 6, since the supply to the circuit 7 has been interrupted by the timing device 5. When the high level is reached, the switch 10 interrupts the electricity supply to the valve 2 so that this valve closes. Simultaneously, the measured result at the circuit 6 is transmitted via the level switch 10 to the indicator or meter 8.

Claims

1. An automatic washing machine cyclically operable to perform a number of washing and rinsing operations in each cycle, the machine comprising program control means for controlling the number of rinsing operations performed in each cycle, measuring means for measuring the quantity of inflowing water required to fill a washing chamber of the machine to a predetermined level and for providing a control signal having a value indicative of such measured quantity, and evaluating means for comparing the value of such control signal with predetermined values and determining in dependence on the comparison result preferred values for the quantity of a washing agent to be supplied to and the number of rinsing operations to be performed by the machine.

2. A machine as claimed in claim 1, further comprising regulating means for regulating the filling level of the washing chamber.

3. A machine as claimed in either claim 1 or claim 2, the evaluating means being adapted to control each of the program control means and washing agent quantity control means for exercising a control function in relation to the quantity of washing agent to be supplied, and the machine further comprising time delay means to provide a delay in such control by the evaluating means.

4. A machine as claimed in claim 3, further comprising a water inlet valve operable to control the flow of water into the washing chamber and switching means for controlling the operation of the valve.

5. A machine as claimed in either claim 3 or claim 4, the measuring means comprising a water meter for measuring the quantity of water flowing into the washing chamber and a pulse transmitter for transmitting to the evaluating means a plurality of signal pulses indicative of the quantity measured by the meter.

6. A machine as claimed in any one of claims 3 to 5, the time delay means being adapted to delay the control of the program control means and washing water quantity control means by the evaluating means for a predetermined period of time sufficient to permit addition of supplementary water to the washing chamber to compensate for water absorption by articles in the chamber.

7. A machine as claimed in any one of claims 3 to 6, the washing agent quantity control means comprising indicating means for indicating the respective preferred value.

8. A machine as claimed in any one of the preceding claims, the measuring means being adapted to measure inflowing water required to fill the washing chamber to a further level above the first-mentioned level, and the machine further comprising a sensor for sensing filling of the chamber up to the lower level and interrupting the supply of water thereto and means for resuming supply of water to the chamber to fill the chamber to the higher level.

9. A machine as claimed in any one of the preceding claims, the measuring means comprising weight sensing means for sensing the weight of water filling the chamber to said predetermined level.

10. A machine as claimed in any one of claims 1 to 8, the measuring means comprising inertia measuring means for measuring the combined inertia of movable means defining the washing chamber and water filling the chamber to said predetermined level.

11. A machine as claimed in any one of the preceding claims, the measuring means comprising a storage device for storing and comparing electrical signals representative of such measured quantity of water with electrical signals representative of different quantities of washing agent to be supplied and different numbers of rinsing operations to be performed for different measured quantities of water.

1.2. A machine as claimed in any one of the preceding claims, further comprising storage means for washing agent and metering means controllable by the evaluating means to supply a metered quantity of the agent from the storage means to the washing chamber.

13. A machine as claimed in any one of claims 1 to 11, further comprising a feed chamber for holding washing agent to be consumed in an operating cycle of the machine and optical display means controllable by the evaluating means to provide an optical display of the quantity of washing agent to be introduced into the feed chamber.

14. A machine as claimed in any one of the preceding claims, comprising means for feeding washing agent in liquid or solid particulate form.

15. A machine as claimed in claim 1, the measuring means being adapted to provide an electrical control signal.

16. A machine as claimed in claim 15, the measuring means being adapted to provide the control signal in digital form.

17. A machine as claimed in any one of the preceding claims, the evaluating means being adapted to determine preferred values providing for a variable number of rinsing operations with a constant filling level of the chamber.

18. A machine as claimed in any one of claims 1 to 16, the evaluating means being adapted to determine preferred values providing for a constant number of rinsing operations with a variable filling level of the chamber.

19. A machine as claimed in any one of claims 1 to 16, the evaluating means being adapted to determine preferred values providing for a variable number of rinsing operations with a variable filling level of the chamber.

20. A machine as claimed in claim 3, comprising a water inlet valve operable to control the flow of water into the washing chamber, and start switching means and first and second level switching means for controlling the operation of the valve, the first level switching means and the second level switching means being adapted to interrupt supply of water to the washing chamber on filling of the chamber to, respectively, said predetermined level and a further level above said predetermined level.

21. A machine as claimed in claim 20, the evaluating means comprising a first evaluating circuit for determining the quantity of washing agent to be supplied and correspondingly controlling the washing agent quantity control means and a second evaluating circuit for determining the number of rinsing operations to be performed and correspondingly controlling the program control means, the measuring means comprising a water meter for measuring the quantity of water flowing into the washing chamber and supplying signal pulses indicative of the measured quantity to the second evaluating circuit during filling of the chamber up to the lower level and only to the first evaluating circuit during filling from the lower level to the upper level, and the time delay means being adapted to delay control of the program control means by the second evaluating circuit until filling of the chamber to the lower level, to bypass the first level switching means to permit the supply of water to the chamber to continue through the inlet valve under the control of the second level switching means so as to fill the chamber to the upper level, and to delay control of the washing agent quantity control means by the first evaluating circuit until filling of the chamber to the upper level.

21. An automatic washing machine substantially as hereinbefore described with reference to Figs. 1 and 2 of the accompanying drawings.

22. An automatic washing machine substantially as hereinbefore described with reference to Figs. 1 and 3 of the accompanying drawings.