GB2262363A

GB2262363A - Determination of operating parameters of a washing machine

Info

Publication number: GB2262363A
Application number: GB9224891A
Authority: GB
Inventors: Johannes Spielmann; Lothar Knopp; Klaus Ruhnau
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-12-13
Filing date: 1992-11-27
Publication date: 1993-06-16
Anticipated expiration: 2012-11-27
Also published as: FR2685016A1; ITMI922841A1; DE4141213A1; JPH05245289A; DE4141213C2; ITMI922841A0; IT1256716B; GB2262363B; GB9224891D0; KR930013336A

Description

DETERMINATION OF OPERATING PARAMETERS OF A WASHING MACHINE Re present

invention relates to a method of determining operating parameters, especially dry laundry mass, water level and absorbed washing solution quantity,in a drum washing machine and to a washing machine for carrying out the method.

Devices for ascertaining the dry mass of the laundry introduced into a drum washing machine, in which measuring sensors fc-, rnec:hanic;.,",, stresses are mounted on machine components loaded by the laundry mass, for example a carrying spider for a soapy water container, are part 04r- t t thal.

he St-:Le Olf: the art (DEE-OS 30 25 003) Devices of - kind, for examp le str a.i n gauges or pic-zoeletric pick-ups;-pprc)pria'i-.e evaluet-ing circuits, and the evaluation of their, signals are reta.t.1,je'y expensive and not always particularly accurate.

TI-iere re-mains a need fora method by which washing machine operating pararleters, such as dry laundry mass, may be ascertainable with additional complication. At the same timne, the accuracy in such parameters shall preferably be inc."eased and the je,satility enhanced, so that, for example, water level in the sc)aDl :y of the washing agent can be water container and the quant i 411 deteri-nined.

According to a first aspect of the present invention there is provided a method f o r determining operating parameters, such as dry laundry mass, water level and tied washing solution, in a drum washing machine with a resiliently suspended soapy water container and a measuring device coupled thereto for detecting the water level in the soapy water container, wherein the height position of the water level is ascertained as a measurement value with respect to a fixedly located component of the washing machine, and the height position measurement values are after each filling of the container with laundry or with water fed to a computer which is caused by a program control device to store individual measurement values and to set stored and, optionally also, actual measured values into relation after each step forward in the program and to cause the computation results to store and/or indicate and/or operation.

initiate a f ur th er computing The ascertaining of the height position of the water level relative to, for example, the base of the washing machine housing in addition to the known ascertaining of the water level with respect to the base of the container opens up a number of possibilities for the ascertaining of parameters significant for washing processes in a washing machine. In that case, the water level without water filling can be set to zero and the height position equal to the height position of the container base above the housing base.

FGr examp ie, according to an advantageous ref inemient ofth e method, the drum can be driven for at least one reiolution and th e height pjsition measurement value can be stored thereafter t h e loading of the washing machine with laundry and the starting of the program sequence. Thereby, the introduced laundry mass will lower the container against the force of the resilient means supporting it arid against the frictional force of any friction dampers damping the movement of the container.

A development of this variant- of the method co,,sists in a difference form.ation between the height position measurement values,,, iith unloaded and with loaded container and setting this difference into reiation with the spring proper-ties in order to ascertain the mass o' the introduced dry laundry by computation.

For ascertaining the supplied quantity of water, the method can is be developed further in that during the introduction of water into the container, the height position of the water level is inter alia ascer ta i ned through the difference between the 1 o,,.,er i n 9 of the container by reason of the water masses further loading the resilient means and the opposite raising of the water level with respect to the container base and is a measure for the supplied quantity of water'. This difference is initially independent on the properties of the introduced laundry, because this is not wetted at the outset by the water-. The lowering of the container in dependence on the introduced' quantity c-10 water is not linear in this program portion because of the different surface contents of the surface at different heights.

By means of a suitable development of the method, in which after the detection of the quantity of water, the drum is turned for a predetermined time and the laundry is wetted, the height position measurement is determined anew immediately after stopping of the drum and the ascertained measurement value is subjected to a computing process in which the absorbed quantity of water is determined in dependence on the reduction in water level that has occurred due to water absorption in the laundry, wherein the absolute absorptive capacity of the laundry can be ascertained. This value, too, can be stored and kept ready as parameter for use in deciding the future program sequence. Moreover, it can be indicated in suitable form at the operating panel of the washing machine.

The absolute absorptive capacity of the laundry can be used to determine the specific absorptive capacity of the laundry, in particular by correlating the computed dry mass of the laundry and the computed absorbed quantity of water.

Moreover, according to a further development of the method, the specific absorptive capacity of the laundry serves as determinant for ascertaining of the kind of laundry. By this means the selection of a suitable washing program sequence and optionally also of a suitable washing temperature can be effected. If the washing machine includes a device for the automatic metering of washing agents kept in storage, a start signal from the operator can, after loading of the washing machine with laundry, suffice in some circumstances to select the washing program sequence which is the most suitable and economical and to set it into motion.

0 S 4 t i,-,n Pre'erabbly, the height po 1 1 measurernent vali-ies are obser.,,ed dur- ing the drum movement and with the water feed shut off and, in the case of an increase of the r,easirement values abo..,,e a r),,edetet- mined threshold value, the increase is classified as foam. As a result, measures which reduce, prevent or- reverse formation of foam can be taken almost immediately foam occurs. These may concern on the one hand the frequency of the drum movernent and on the other hand the water heating or, during rinsing, the water feed and optionally also intermediate spinning operations.

the method can advantageously be developed further for application in a spinning program phase, in which the wate,- fe-d is b]G,-ked and the water level measurement value or conDuted value is er-,,, jal to zero, in that the height position measurement value and the rotational speed of the drive -motor or of the drum are observed and, or, a change in the measurement value in a rhythm similar or equal to the rf-- ,'Lational speed of the drum and with an amplitude above a threshold value, an associated imbalance is classified as a criterion for a change in the spinni9 program phase. The relation between height position measurement value and rotational speed of the drum thus permits reliable ascertaining of imbalance, the recognition of which can be used for the spinning program. control The spinning program can be (--,ptimised even further when bet,.jeen at least two spinning phases and while the drum is at standstill the height position measurement value, which was ascertained and stored dr M f 1]C), ading of after at least one rotation of the U 0 wing the]c Lhe washing machine with laundry, is compared with the height measurement T" is value ascertained during the standstill of the drum between the spinning phases and/or immediately after the - for the time being last spinning phase, the computed difference being a measure for the ascertained residual moisture in the laundry. Since certain residual moisture values must be reached, or suitably high residual moisture values suffice for some requirements, the structuring of the spinning program sequence can by contrast to previously practised rigid associations with coarse selection criteria (for example "white and coloured laundry" with high spinning speeds; "synthetic" with low spinning speeds) be adapted continuously or in fine steps to a range of selection criteria. Correspondingly, the method can be developed further in that the computed value of the residual moisture can be used as a criterion for the decision on whether a spinning stage should be performed with an adjoining further spinning phase and/or at which rotational speed such an adjoining spinning phase should be carried out or should or can be prolonged or shortened.

According to a second aspect of the present invention there is provided a washing machine with a soapy water container resiliently suspended in a housing frame and with a level-measuring device for the water level, which device is arranged for the detection of the water level in the container relative to its base, the machine being adapted to perform the method according to the first aspect of the invention in that the measuring device is additionally arranged for the detection of the water level in the container relative to the housing frame.

T" 7 xa,'ples of the method and embodiments of the washinc machine of the present invention will no,,.,, be more particularly described with reference to the accompanying drawings, in which Fig. 1 is a schematic view of a soapy water container, laundry drum and water level measuring device in a washing machine embodying the invention, Fig, 2 is a schematic sectional of a f irst form of the measuring device, Fig. 'I is a schematic sectional viea of a second forri. of the measuring device; a S c h e,,-n at i c v i c-,,-/ S h owi n 9 a s i g na 1 s It- ate 01: t I e measuring device in the case where the drum is filled laundry only; Fiq. 5 is a schematic viej similar to Fig. 5, but showing a signal state when the drum is additionally filled with water; and Fig. 6 is a diagram illustrating steps in performance of a method exemplifying the invention.

Referring now to the drawings there is shown in Fig. 1 part of a washing machine with a laundry drum 2 horizontally mounted in a soapy viater--9rtair.er spring legs 4, which contain friction shock absorbers and the ends of which are pivotably connected with a base plate 5 of the washing machine. The interior of the container 1 is connected by wa.v of a connecting duct 6, which co,,,r.municates with the base of the 1. The container 1 bears by way of a saddle 3 on 9 container, with a hollow cylindrical or prismatic housing 7, in which a float 8 is guided to be vertically movable. The housing and float represent a height position measuring device 9, which is connected by means of a rod 10 of the float 8 with a position transmitter 11. The transmitter is arranged in fixed location in the housing structure 12 of the washing machine, for which reason the rod 10 and a guide 13 thereof must be constructed to be flexible or resilient. A Bowden cable pull could serve as the rod and guide. The casing of the Bowden pull, thus the guide 13, is enlarged at its upper end to form a core housing 14, which is guided to be longitudinally movable in a coil 15. In order that the core housing 14 can maintain adefined zero position, it is suspended by a light spring 16 at the housing 17 of the position tr an sm i tter.

A core 18, which consists of ferromagnetic material and is firmly 15 connected with the upper end of the transmitter rod 10, is guided within the core housing 14. According to thepri'nciple of the circuit in which the coil 15 is incorporated, the core 18 can be magnetised or not magneti sed. Terminals 19 of the coil 15 are connected with evaluation equipment (not shown).

Two forms of height position measuring device 9 are illustrated in Figs. 2 and 3. In Fig. 2 a hollow cylindrical transmitter housing 7 is connected by way of a large duct 6 with the container 1. A duct 20, through which flushing of the housing 7 can take place on the inflow of the water, opens at the upper side of the housing. The float 8 is rigidly fastened to the rod 10 and is guided by its outer casing, which can be ribbed for reduction in friction,in the housing 7. 'the rod jo is guided through a tight upper openina in the transmitter housing so that the float 8 cannot cant over in the - 8 has two or rriore uniformly distributed passages housing. The f I oat.

21 through which water flowing into the housing from the feed duct 20 can pass away downwardly to the container 1.

The measuring device 9 illustrated in Fig. 3 operates on a pressure cell measurement principle and comprises a housing 24 connected by way of a rigid connecting duct 6 with the container 1. In place of a float, a diaphragm 22 -clamped firmly and Zealingly in the housing. In the case of increasing pressure due to water ri sing in the container 1, the diaphragm i s deflected upwardly. Ar. --.quilib- iu,n sets in between the pressure 4 in the container and a spring 2, which is disposed between the diaphragm, and the upper part of the housing 24. Similarly to the device 9 of Fig. 2, a transmitter rod 19 is mounted at the diaphragm and moves together with the diaphragm. It t Lransmits the diaphragm deflection to a position transmitter (11 in Fig. 1 rigidly secured to the housing structure 12. A duct 25 opens on the righthand side and serves for the feed of fresh wtater, so that t.he interior of the housing 24 underneath the diaphragmi can be flushed free of deposits. A method for ascertaining the mass of laundry charge placed in the container 1 and for ascertaining the quantity of water that has 1 1 owed into the container 1 will no!.,j be explained by reference tc Figs. 4 and 5. The container 1 in Fig. 4 is without water. 25 Consequently, the float 8 of -t11-he height position measuring device 9, - the base of the transmitter housing 7.In the coT.ple'tc-1j, lies all unloaded position, which can be calibrated by carrying out one to two revolutions of the empty drum, the container 1 assumes a position in which a pointer 26 of the rod 10 points to the mark "0" of the height position measuring scale 27. As soon as the laundry 28 has been introduced into the drum 2 and the drum has revolved at least one in order that the laundry can tumble within the drum, and, through its energy thereby acting on the container 1, overcomes the frictional force of the friction dampers within the spring legs 4 (Fig. 1), the container together with the measuring device 9 lowers into a position illustrated in which the pointer (26) points to the mark "4 Kg" of the scale. The deflection of the container on the introduction of a mass of 4 kilograms is generally between 3 and 4 millimetres.

In Fig. 5, a 6 litre quantity of water 29 has been filled into the container 1 through suitable filling duct means. Due to the weight of the water quantity, the container 1 lowers out of the position, illustrated in Fig. 4, i.e. the position in which the pointer 26 pointed to the mark "4 Kg". At the same time, however, due to the filling of the housing 7 with water from the container, the float 8 rises into a position causing the pointer 26 to point to the mark "4 Kg + 6P' of the scale 27.

As soon as the laundry 28 has been wetted to a greater extent through the rotation of the drum 2, water gets through the binding in the laundry fibres above the water surface level, so that the water surface level falls although the water quantity 29 present in the container 1 has not reduced. Thereby, the pointer 26 falls to below the value "4 Kg + 6P' on the scale 27.

T" A washing program now be explained iith reference to the diagram in Fig. 6. The statuses drawn in circles represent program points, wherein the less strongly drawn circles are points which arise at least theoretically because the associated prograTi courses interengage. The thick c3nrecting lines between the status circles represent the courses of the respective status changes in the direction towards the less strongly drawn circles, but at least the L.heoretical courses.

F The abscissa in the diagram of Fig. 6 denotes the mass o-1 L1In e -7 contents in the container, including the drum space. the- Lainer zero point of the abscissa represents the mass value of the cont when emDty.

Pnce the container is suspended or supported resiliently, a certain reference point of the container, for example the lowest point is ci: its base, will lower perceptibly on the introduction of a further mass. This lowering is perceived as a downward def lection of the 2 6 i ts pointer 26 on the ordinate. Since', however, the pointer c operatively connected with the floa- 8, which indic-tes the water - point of its base, the pointer leiel 'in the container above the 1 owe s t deflection, which is initially downward, is adjusted upwardly as soon as 'the water surface level is raised. Correspondingly, the pointer deflection is again adjusted downwardly when the water surface level -ainer by the par t of falls, for example on absorption of wate. in the conll the laindry above the water surface level. The pointer deflections can be read of,' on the ordinate of the diagram of Fig. 6.

T- The characteristic curve 30 is a theoretical characteristic which indicates the water level in dependence on the water quantity (kilograms) added to the container for the case that the container is mounted completely rigidly at, and in invariable location with respect 5 to, the washing machine housing (thus for rigid support legs). Because of the geometry of the container - the hollow body filled by the added quantity of water is a cylindrical section - the curve 30 as well as all the curves derived therefrom extend with clearly degressive slope in the lower detection range.

BY comparison therewith, the solidly drawn characteristic curve 31 denotes the deflection of the pointer 26 (Figs. 4 and 5) on charging of the not rigid, thus resiliently supported container with a respective water mass, the value of which is denoted at the line by small numbers (in litres or kilograms). The spacing of the locii of the curve 31 from the same locii of the curve 30 on the abscissa is fixed by the spring constant (curve 32) of the spring legs 4 supporting the container. The spring constant is typically 0.8 millimetres per kilogram.

The lowering of the drum along the curve 32 can take place only when the float cannot be raised through the introduction of a mass into the container. This applies, for example, on loading of the container or drum with laundry. If, for example, starting from the zero point, the drum 3 is loaded with laundry 28 with a mass of four kilograms, and the frictional force of the friction dampers integrated in the spring legs 4 is overcome by at least one revolution of the laundry drum with the dry laundry, the oscillating c ontainer system reaches a status I and deflects the pointer downwardly through 3.2 millimetres on the scale 27.

1he pointer defection was initially measaured with the containe. unloaded in order to calibrate the measuring systen, to zero. Af ter the lowering of the container in consequence of the loading with, laundry, the status I is stored. The pointer deflection is used to determine the mass of the introduced laundry by means of a microprocessor of the washing machine, taking into consideration parameters such as mass of the oscillating system, spring constants and further influences on the oscillatory system. The value of this can, i-i" desired,be indicated for the operator in a display oil the operating panel.

Starting from the status I, wlater is now added to the container, initially in a quantity of 6 litres, Thereby, the float rises and the 33 to the height of a status p,intei- 9-6 rises according to the curie.

II, in which the le-iel of the water in the container indeed touches the drum and the laundry lying therein, but, without intermixing of the laundry and the water, causes hardly any wetting of the laundry. In the status II, the pointer 26 reaches a height at which the measuring device generates a signal for the switching-off of the water feed. A water inlet valve is accordingly closed.

If the drum is rotated with a water level below 6 litres, then a 1 part of the added water wets the laundry. A status III is then eithec not reached, for example in the case of time control of the water feed, or more than 6 litres oil water has flowed in at a water level height similar to the status II, for example as for a later status IV.

A. nethod is therefore prefereed in which the drum is st-ltionary during the fi's"-- water filling.

ir The drum is then moved in reversing manner in a time-limited phase, whereby the laundry is repeatedly immersed in the soapy water and is rained on from above by the quantities of water raised by the illustrated triangular section entraining members in the drum (Figs. 4 and 5). In that case, the laundry takes up an indefinite quantity of water and thereby reduces the water level relative to the container base. At the end of this phase, the drum is stopped and the new water level, which has set in for the status III, is immediately measured.

The amount by which the water surface level has dropped indicates the quantity of the water absorbed by the laundry. No other interpretation of the lowering of the pointer 26 is possible, since no measure was contained in the program sequence which could have effected a change in mass of the container. Thus, a first provisional conclusion concerning the water-absorbing capacity of the laundry is is possible. From this, a probably required replenishing quantity can be computed for the second stage of the water feed and preset for the control of the water feed.

After renewed opening of the water inlet valve, the water quantity now rises according to the curve 34 to a status IV. Now, 6 litres of water are disposed as free washing solution and two litres of water are disposed as absorbed or tied washing solution in the container. In that case, the float 8 is raised again, but the height position of the pointer 26 lowered somewhat in correspondence with the added quantity of replenishing water. Since the raise of the water surface level predominates over the lowering of the system, a slight rise of the height position measurement value results by comparison with the status III. This rise, however, lies below the height position after the feed of the first 6 litres of water, because 2 litres of water now make up more mass in the container.

- is - The height position is s!lbsc-quentLly lo red;2ain in reve-sing manner in a time-limited phase. The laundry takess up a ii-urther indefinite quantity o, water, in the present example about 1 litre of water, so that a new status V arises as soon as the drum stands still again.

The measurement values which have been obtained and stored in the meantime permit computation that the laundry has so far absorbed e tota 1 of three litres of water and is probably no longer capable ol absorbing further water to a noteworthy extent. Through the described cycles i n conjunction,mii th a washing machine equipped with the measuring equipment, the water -absorbing capacity of the;,,.jr.dry can beascertained very accurately and the presumed further w,- U capacity can be estimated in advance.

In the next replenishing cycle, only a quantity of one litre is - t is adtic-r-',, so thUt Lhe water level gets, as the difference between the increase in the level and the lowering due to the mass, to a status'li. 1 if the laiinr-,lry is no longer capable of absorption, each change in water level then remains on the curve 35 and the water lejel initiall.., at th- status VI.

This new height position measurennient value is again fed to the computer, which from this can compute the entire water absorption 0-.:' the laundry. The microprocessor control can compute the specifi wate-abscrbing capacity from the parameters "filled-in quantity of .iater" and "qLjantity of water absorbed by the laundry" and determine, by reference to a stored table, the class ol laundry of which the introduced laundry charge is composed. If the laundry absorbs - 16 water for relatively high weight, then a synthetic fibre is likely, as this does not absorb very much water. If, thereagainst, a cotton laundry charge is concerned, a relatively large amount of water may be absorbed for a relatively low mass of laundry. The curve 35 would then lie relatively far to the right.

In the case of the illustrated example, a laundry charge of synthetic fibres is involved, because the absorbed quantity of water of three litres stands in relation to four kilograms of laundry as a low proportion of absorbed water. A cotton laundry charge of this order of magnitude could absorb more than three times as much water, thus about 10 to 12 litres.

Since the water feed is terminated after this last water take-up cycle, preliminary washing can begin with reversing movement of the drum. After termination of the preliminary washing operation, the free washing solution is pumped away without further movement of the laundry in the drum. In that case, the height position measurement value moves on the curve 35 downwardly to status VII. In this status, there is no longer any free washing solution in the container, but only the mass of laundry (4 kilograms) plus the absorbed washing solution (3 kilograms). Correspondingly, the height position measurement value is 5.6 millimetres below "0" Ir -he 'beginning of the 7-,ain washinz 511a ---r 1 s again al]owed in at t operation. In that case, the height position measurement value nc..,i rises along the curve 35 beyond the A greater quantity o-IF water (here main washing. Correspondingly, the in the status VIII rises to nearly status VI and into a status 'I'LI I1. 13 litres) is then needed for the height position measurement value 15 millimetres above "0". " t the m end of the main washing operation, the soapy water is pumped out of the container, while the water level falls further down along the j until the statu.s 'ITI, as at the end of curve 35) beyond the status 1 J.

the preliminary washing operatiGn, is reached. -us IX, which In the rinsing phase, the water leve reaches a stal.

results in a height position -,teasirenent value of, for example, 5,2 millimetres, several times along the curve 35. During the rinsing ---r level is changed several times along the curve 35 operaticn, the or 1,j,.,iererJ to the status VII at which no nore free washing solution is Present in the container.

A fl t er completion of the rinsing operation, no free washing soitirin is present in the container and the status VII is reached. A.

spinning program phase then begins. The drum is moved at a slowly rising rotational speed and in that case deflects out of a circular locus by reason of an undefined imbalance. In that case, the container oscillates up and down v i i t h a corresponding undefined amp]-it,,jdc-. This amplitude produces a deflection of the pointer 6 L,.-,iieen minimum and maximum height position measurement values. These values can be recorded and co-mpared in the microprocessor with a stored threshold liatue. The reaching or exceeding of such threhsol,-,' a values is then converted into a termination signal for the spinning. After termination and slowly reversing drum movement, during which the laundry redistributes in the drum, spinning can be resumed until an imbalance - represented by the minimum and maximum height position measurement values - which is reasonable for the final spinning speed is present. The tumbling movement of the container can also be measured during the drum rotation at the desired final spinning speed in order to be able to reduce the speed at any time if an unacceptable imbalance arises.

Ascertaining of residual moisture can be undertaken at standstill of the drum during the reversing intervals of the spinning program phase. For this purpose, the height position measurement value is recorded and set into relation with the stored measurement value associated with the dry mass of the laundry introduced before the first inflow of water. Thedifference between the two measurement values is a measure for the washing solution still in the laundry, i.e. the absolute quantity of residual moisture in the laundry. The precentage residual moisture is obtained in relation to the dry mass of the laundry.

The curve 36 indicates the highest water-absorbing capacity for a laundry charge of synthetics present in, for example, the maximum charge capacity, such as 5 kilograms. In the case of a laundry charge of maximum charge capacity, but of a material more capable of absorption, this curve 36 lies further to the right. For example, a laundry charge, weighing 5 kilograms, of cotton terry towelling would have a maximum water-absorbing capacity of 15 litres (= 300%) and in saturated state would lead to oscillation of the height position measurement value along the curve 37 illustrated in chain-dotted lines at the far right.

The lower dashed) limiting line 33 indicates the iiater L. 1 ev e 1 i n the container for the case that water contact by the 'Clater level has not yet taken place. Even if this water level is exceeded after the first filling of the container with,iater (6 litres", the laundry is j - wetted only insubstantially. The reasons for this are that only laundry items actually lie at the base of the drum and that completely dry laundry, particularly if contaminated with fat components, may not readily absorb water.

By means of the method hereinbefore described, the entire process can be automated in a respective staging after the introduction of the laundry. As soon as the weight of the laundry has been indicated at the operating panel to the operator, the oDerator can meter and put ilr a quantity oil washing agent appropriate for preliminary washing.

m.;:, A' t e r a s c e r t a i n i n 9 the S p e c i f ii c.i a t e c - a b s o r b i n 9 capacity 0 f t h e.

is introduced laundry, the laundry can be classified and indicated at the panel. According to dry mass and type of laundry, the operator can, then meter and put in the washing agent quantity required for the main washing operation. The selection of the l,iashi:ng agent quantities can, however, also be undertaken by the microprocessor and indicated as an instruction at the panel. If the washing machine is equipped with a system for automatic metering c-10 washing agents stored in the viashiri-, machine, for example, in liquid form, then the entire washing process can even take place completely automatically after the operator has loaded the aundry Into the machine and entired a start signal at the panel.

Claims

CLAIMS ro 1. A method of determining operating parameters of a

programcontrolled washing machine with a resiliently mounted water container housing a laundry dr um, the method comprising the steps of ascertaining the height position of water level in the container as a measurement value with respect to a fixed reference point in the machine on each occassion of introduction of water into the container and laundry into the drum, storing th.e ascertained height position measurement values in computing means, processing ascertained height position measurement values in the computing means, and carrying out at least one of a storage step, on indicating step and a step of initiation of a computation procedure in response to the processing result, the steps of storing, correlating and carrying out being performed in dependence on advance of the control program of the mach i ne.

2. A method as claimed in claim 1, wherein the correlated values compirse stored height position values.

3. A method as claimed in claim 2, wherein the correlated values comprise instantaneously ascertained height position values.

4. A method as claimed in any one of the preceding claims, wherein the steps of ascertaining and storing are performed after rotation of the drum through at least one revolution following introduction of laundry into the drum and starting of the program.

T r, A 7Ethod as claimed in any one of the preceding claims, wherein the steo of correlating comprises determining the difference bet,.,ieen ascertained height position ialues f or respectively loaded and unloaded states of the container, correlating the determined difference with a value indicative of the resilience of the container mounting, and determining from the correlation result the dry mass of laundry in the drum.

6. A method as claimed in any one of the preceding claims, wherein,he step of ascertaining comprises detecting the extent of lowering G', the container on its resilient mounting on introduction of water intc the container, detecting the extent of rise of the water within th. e container, and determining the quantit/ of introduced water as a f unction of the difference between the detected extents.

7. A method as claimed in claim 6, further comprising the steps of - he rotating the drum for a predetermined time after determination of t - v introduced,.iate!- quantity to cause laundry in the drum to be wetted b. the water, stopping the drum rotation and reascertaining the height position cif the water level, and determining the quantity of absorbed by the laundry as a function of the difference between height 20 position values ascertained respectively before and after the dru-. rotation.

8. A method as claimed in claim 7 when appended to claim 5, comprising the step of determining the specific absorptive capacity in dependence on the determined dry mass of the laundry and determined water quantity absorbed by the laundry.

9. A method as claimed in claim 8, comprising the step of determining the type of laundry in dependence on the determined specific absorptive capacity thereof.

10. A method as claimed in claim 1, comprising the steps of rotating the dr um af ter termination of water feed into the container, continuously ascertaining the height position of the water level during the rotation, and classifying as foam any increase of the ascertained height position measurement value beyond a predetermined threshold value.

11. A method as claimed in claim 1, comprising the steps of rotating the drum in a spinning phase of the program with water feed to the drum shut off and with the ascertained height position equal to zero at the outset of rotation, continuously ascertaining the height position by measuring means also responsive to machine oscillation, monitoring the rotational speed of the drum directly or indirectly, recognising drum imbalance from fluctuation in the height posi-tion value in a rhythii similar or equal to the monitored rotational speed and at an amplitude above a predetermined threshold value, and classifying such recognised imbalance a criterion for a change in the program.

1 Ir 12. A meethod as claimed in cla-im 4, comprising the step of the height position value ascertained and stored after the drum rotation with at least one of a height position value ascertained during standstill of the drum between two spinning phases of the f e program. and a height position value ascertained immediately alt r t 1 ermination o-O a designated final such spinning phase of the program, and determining the residual moisture in the laundry from the comparison- result.

13). A me t ho d a s claimed i n c 1 a 1 ri 11 ' comprising the step 01::

determining at least one of number, duration and drum rotational speed of any further spinning phase of the program in dependence on the determined residual moisture.

11,. A -,,ethod as -]aimed in claim 1 and substantially as hereinbefore described reference to Fig. 6 of the accompanying drawings.

15. A program-control led washing machine for performance of the method claimed in claim 1, comprising a water container resiliently mounted in a body structure of the machine, a laundry drum housed in the container. and a level measuring device lor measuring the level of water in the container relative to the base thereof and relative to a reference point fixed with respect to the body structure.

1, 16. A washing machine as claimed in claim 15, wherein the level measuring device comprises a housing rigidly connected to the container and disposed in flow communication therewith by way of duct means connected to the container in a base region -19.hereof, a float arranged in the housing to be raisable and lowerable by water entering and leaving the housing, an elongate signal element displaceable by the float, and a position sensor fixedly connected to the body structure and co-operable with the signal element to detect the position thereof and to provide a signal indicative of the detected position.

17. A washing machine as claimed in 15, wherein the level measuring device comprises a housing rigidly connected to the container and disposed in flow communication therewith by way of duct means connected to the container in a base region thereof, a diaphragm is arranged in the housing to seal off a pressure chamber communicating with the duct means and to be deflectable by change in pressure in the chamber, biassing means to bias the diaphragm against deflection by pressure increase in the chamber, an elongate signal element displaceable by the diaphragm, and a position sensor fixedly connected to the body structure and co-operable with the signal element to detect the position thereof and to provide a signal indicative of the detected position.

18. A washing machine as claimed in claim 14 or claim 15, wherein the elongate signal element comprises a rod or cable provided at afree end thereof with signal means-.

I 19. A washing machine as claimed in claim 18, wherein the siqra means coimprises a core of ferromagnetic material and the sensor comprises a fixedly disposed coil surrounding a path of movement e,' the core and means to derive Irom the coil a signal indicative of depth of entry of the core into the coil.

C 2 (). A washing machine as claimed in claim 18, wherein the signal means comprises a first electrode and the sensor comprises a second electrode and means to derije from the common capacitance of the elc-ctr3des a signal indicative of the spacing or overlap of -IC he electrodes.

21. A viashing machine as claimed in claim 18, wherein the signal rneans co:-priIses a;.,iper element of an adjustable resistor and the sensor comprises means to derive from the resistor a signal indicative -.1 of the stet.ing of the wiper element.

is 22. A washing miachine as claimed in claim 18, wherein the signal means comprises a portion o, the rod or cable with optical"j dtinquishable regions and the sensor comprises means to provide a ist light beam in a path of moiement of said portion and means to deri:e from r-eflectance or transmission of the beam by the regions a signal indicative of the position of said portion.

ir 23. A washing machine as claimed in claim 8, wherein the signal means comprises a pressure-exerting portion of the rod or cable and the sensor comprises a piezoelectric pressure detector to detect the exerted pressure and means to provide a signal indicative of the 5 detected pressure.

24. A washing machine as claimed in claim 18, wherein the signal means comprises a portion of the rod or cable with, an acoustically reflective surface and the sensor comprises transmitter -receiver means to transmit sound waves to and receive reflected sound waves from said portion and means to derive from the reflected waves a signal indicative of the position of said portion.

25. A washing machine substantially as hereinbefore described with reference to Fig. 1 of the accompanying drawings.

26. A washing machine substantially as hereinbefore described with reference to Fig. 2 of the accompanying drawings.

27. A washing machine substantially as hereinbefore described with reference to Fig. 3 of the accompanying drawings.

28. A washing machine substantially as hereinbefore described with reference to Figs. 4 and 5 of the accompanying drawings.

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