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DETERMINATION OF WASH LOAD SIZE

IP.com Disclosure Number: IPCOM000005736D
Original Publication Date: 1988-Oct-01
Included in the Prior Art Database: 2001-Oct-31
Document File: 2 page(s) / 111K

Publishing Venue

Motorola

Related People

Rolf Kowalewski: AUTHOR

Abstract

The effectiveness of a washing machine to cleanly wash clothes is determined by many factors, most of them relating to the size of the wash load or the amount of clothes washed at one time. Some attempts have been made in the past to allow the load size lo be determined by the user by incorporating scales in the lids of washing machines, but the acceptance of these can best be judged by theirdisappearance. If this determina- tion of wash load could be accomplished automatically a more effective use of the washing machine could be the result.

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MOTOROLA Technical Developments Volume 8 October 1988

DETERMINATION OF WASH LOAD SIZE

by Rolf Kowalewski

   The effectiveness of a washing machine to cleanly wash clothes is determined by many factors, most of them relating to the size of the wash load or the amount of clothes washed at one time. Some attempts have been made in the past to allow the load size lo be determined by the user by incorporating scales in the lids of washing machines, but the acceptance of these can best be judged by theirdisappearance. If this determina- tion of wash load could be accomplished automatically a more effective use of the washing machine could be the result.

   An arrangement of the components of a typical washing machine is shown in Fig. 1. The tub (I), transmis- sion (2), motor (3) and water valves (5) are common to every washing machine built in recent times. Usually the motor control (4), logic (7), input and display (8) consist of a mechanical timer. The trend is however to replace these items by reasonably 'smart' electronic controls. The water level sensor (6) is usually capable of detecting only a few, discrete water levels and is therefore not capable of drawing any useful information from the above discussed facts and it might prove difficult to improve its sensitivity due to the harsh environment produced by the detergent solutions and temperatures used.

   With the addition of the water flow meter (9) in the relatively clean water supply it is possible to repeatedly measure exact volumes of water input and thus draw conclusions as to wash load size and hence amount of detergent to be added and amount of water to be used. It would be practical to automatically meter liquid detergent added by the detergent dispenser (10).

The following events can now be observed if some "fill" agitation is used lo insure complete wetting and submersion of clothes as water level permits:

1)

If a fixed water level (e.g. 5 gallons) is reached when an "empty" volume (also 5 gallons) has been filled into the tub, either of two conditions must exist:
a) The tub has no clothes in it - it is "empty': or
b) The amount of wet clothes above the water has suspended the exact volume of water displaced by the clothes submerged.

If the fixed water level is reached before "empty" volume has been filled into the tub-either of the follow- ing must be true:

a) All clothes are submerged and have displaced their weinht of wnterifimt anllmntinn~ which k em~rl to the difference between the "empty" and

2)

3)

-. ..-.-. ~ ..-.----... r .._..,, . . ..-.. .___I__.
the actual fill volume.
b) Not all clothes are submerged and only their...