GB2136456A

GB2136456A - Method and apparatus for washing textiles

Info

Publication number: GB2136456A
Application number: GB08406220A
Authority: GB
Inventors: Walter Heissmeier; Irmgard Rothmund
Original assignee: Licentia Patent Verwaltungs GmbH
Current assignee: Licentia Patent Verwaltungs GmbH
Priority date: 1983-03-11
Filing date: 1984-03-09
Publication date: 1984-09-19
Also published as: DE3308611C2; FR2542339A1; DE3308611A1; IT1175442B; IT8419955A0; GB2136456B; GB8406220D0

Abstract

In a method of washing textiles in a drum-type washing machine, the washing drum (2) of which comprises perforations (3) over its whole generated surface for the passage of water or detergent solution, the drum is so rotated at a speed just sufficient to cause the items of washing to bear against the inner wall of the drum under centrifugal force and the items of washing are sprayed with detergent solution through the perforations in the drum wall until they become saturated a small surplus of free detergent solution is formed in the drum, thus reducing water and energy consumption. <IMAGE>

Description

SPECIFICATION Method and apparatus for washing textiles The invention relates to a method and an apparatus for washing textiles in a drum-type washing machine, the washing drum of which comprises over its whole generated surface perforations for the passage of water or detergent solution.

In the known drum-type washing machines, the washing to be washed is washed in a heated detergent solution flowing through the perforations in the washing drum. As a result of mechanical movement of the washing backwards and forwards, the elimination of the dirt from the washing to be washed is effected by means of the detergent present in the detergent solution. The heating up of the detergent solution is generally taken care of by a heating element which is disposed in the bottom region of a wash tub receiving the washing drum inside it. Carrying out this method, wherein the washing is conveyed through the detergent solution by the rotating washing drum during the washing operation is extremely expensive in energy, however, because of the heating up of the detergent solution consisting of a comparatively large amount of water.Furthermore, a large amount of water also requires an increased addition of detergents in order to prepare a more effective detergent solution.

In order to reduce the energy consumption, a method has already become known for drum-type washing machines (DE-OS 31 34 546) which consists essentially in that, in a first washing phase in the presence of a detergent, a comparatively small amount of water is first fed to the washing and is then heated up to a desired washing temperature. In a second washing phase, a further amount of water, which is cold however, is supplied to the heated detergent solution, likewise with the addition of detergents, but is no longer heated up and is only intended to serve to keep the dirt eliminated from the washing in solution in a higher proportion of detergent solution.

It is an object of the present invention to provide a method of washing wherein the water consumption and hence also the energy consumption can be still further reduced without a deterioration or impairment of the washing or cleaning effect occurring. It is a further object of the invention to provide an apparatus suitable for carrying out such a method.

The invention provides a method of washing textiles in a drum-type washing machine, wherein in one-or more washing and/or rinsing operations the drum is rotated at a speed at or slightly above that required to maintain items of washing held against the force of gravity in a ring of washing distributed around the periphery of the drum whilst a washing and/or rinsing liquid is sprayed onto the ring of washing from the exterior of the drum through perforations in the wall of the drum in a quantity just sufficient to saturate the said ring of washing and/or just sufficient to form a free body of washing and/or rinsing liquid within the drum.

The invention further provides an apparatus adapted to operate in accordance with the method of the invention.

The advantages which can be achieved by the invention are to be seen, inter alia, in that the washing of items of washing can be carried out in a drum-type washirg machine practically without any free detergent solution and so with a minimum of water, detergent and energy consumption, without a deterioration in the washing results hitherto usual. The proposed economy method of washing thus contributes to the reduction of environmental pollution.

The invention is illustrated by way of example in the accompanying drawing, the single figure of which is a diagrammatic elevation illustrating the construction of a washing drum such as is particularly well suited for the proposed economy method of washing.

A washing drum, which is provided, over its whole generated surface, with perforations for the passage or entry of water or detergent solution, is first operated briefly, after the insertion of the items of washing to be washed, at a speed of rotation which is between 800 to 1000 revolutions per minute (with a washing-drum diameter of 480 mm). Then the speed is lowered to a value which is somewhat higher than the usual speed of the apparatus required to produce a centrifugal force of 1 g (about 80 revolutions per minute), at which dry items of washing still just bear against the rotating wall of the drum. Thus a satisfactory adhering of the items of washing to the inner wall of the drum is achieved in the form of a ring of washing. As a further method step, the detergent solution necessary for thoroughly moistening the items of washing is prepared.For this purpose, only such an amount of water is heated up in a heated water tank or by an electrical continuous-flow heater that, after the admixture of fresh or cold water, an amount of detergent solution results which is sufficient to saturate a certain amount of washing adequately with detergent solution without free detergent solution forming in the washing machine. The amount of water heated up and possibly mixed with cold water and so brought to the particular washing temperature necessary is supplied, with the addition of the detergent needed, to a storage tank or reservoir which may be provided with an appropriate thermal insulation. As a result, the effect is achieved that a uniform solution or suspension is formed before the actual supply of the detergent solution.The hot and concentrated detergent solution produced in this manner is then sprayed, possibly with a further addition of water for the purpose of dilution, from the outside, through the perforations in the washing drum, onto the items of washing forming a ring of washing adhering to the inner wall of the drum until they are saturated or somewhat below: A method would also be conceivable wherein the items of washing were sprayed with detergent solution until the formation of a free detergent solution was reported to a programme control unit. This free detergent solution formed could then be supplied to the washing again by pumping back. The wetting of the washing can also be briefly interrupted the speed of rotation of the washing drum being reduced to a washing speed of about 50 revolutions per minute.This measure is effected for the purpose of piling the washing afresh. Then the speed is increased again to 80 resolutions per minute and further wetting of the washing is effected. During the spraying of the items of washing with the hot detergent solution, the washing drum is operated at an intermediate speed which is below the usual centrifugal speed but above the usual speed of the apparatus for dry washing of about 80 revolutions per minute. Thus a uniform complete absorption by the items of washing is achieved without these coming detached from the drum wall during this operation. The conveying of the detergent solution from the storage tank or reservoir to a spray nozzle device can be carried out by a separate pump, a siphon or by a water-jet pump with which a dilution of the detergent solution can also be carried out at the same time.

Furthermore, an appropriate reheating of the detergent solution can be effected by this means, if necessary. After the saturation of the items of washing with detergent solution has been reported, the intermediate speed of the washing drum is reduced to about 50 revolutions per minute to release the items of washing or the ring of washing bearing against the inner wall of the drum. The operation of releasing the items of washing may be carired out repeatedly in an advantageous manner. Before reducing the drum speed, a further reheating may possibly be carried out by means of radiant heat or by means of hot air. After the detachment of the items of washing saturated with detergent solution for the drum wall, these are subjected, in the following washing operation, to the usual mecahnical actions (with or without reversal of the drum) to loosen the dirt.

After each of the centrifugal operations ending the mechanical washing operation, the washing drum is again operated at a speed of the apparatus of about 80 revolutions, somewhat below the centrifugal speed, for the purpose of forming a ring of washing bearing against the inner wall of the drum. The rinsing water is sprayed in the same way as the detergent solution onto the items of washing (ring of washing) bearing against the inner wall of the drum, likewise through the perforations in the washing drum, until they are saturated.

The saturation of the items of washing with detergent solution or rinsing water and the formation of a free detergent solution is monitored by one or more sensors or the like. The temperature measurement is effected with a temperature-sensing member of the usual type which is preferably taken through the axis of the washing drum. Other arrangements would be conceivable. The monitoring of the temperature may also be effected in such a manner that the inflow temperature of the detergent solution is measured and the reheating of the detergent solutions which may be necessary therein is carried out periodically.

The washing drum 1 , which is illustrated in the drawing and which is particularly well suited for the economy method described above, is surrounded by a wash tub 2 and comprises, in its rotating generated surface, a plurality of perforations which may appropriately consist of punched holes 3 with outwardly directed giilplates 4 obtained by stamping in. The gill-plates 4 are staggered in arrangement in such a manner that the gill-plates of one row 5 extend in the diagonal direction in relation to the width of the drum wall. Disposed above the washing drum 2 is a spray nozzle device 6 directed onto the outer wall of the drum and in communication with the storage tank or reservoir already mentioned for the detergent solution. During the spraying operation, the washing drum 2 rotates in the direction of the arrow in which the best possible spraying effect on the items of washing is ensured.

Claims

1. A method of washing textiles in a drum-type washing machine, wherein in one or more washing and/or rinsing operations the drum is rotated at a speed at or slightly above that required to maintain items of washing held against the force of gravity in a ring of washing distributed around the periphery of the drum whilst a washing andtor rinsing liquid is sprayed onto the ring of washing from the exterior of the drum through perforations in the wall of the drum in a quantity just sufficient to saturate the said ring of washing and/or just sufficient to form a free body of washing and/or rinsing liquid within the drum.

2. A method of washing textiles in a drum-type washing machine, the washing drum of which comprises perforations for the passage of water or detergent solution over its whole generated surface, comprising the following steps: a) placing items of washing in the washing drum, and then briefly rotating the drum at a speed which lies between 800 and 1000 revolutions per minute; b) reducing the speed of rotation of the drum to a value which is somewhat higher than the usual speed of the apparatus of about 80 revolutions per minute; c) spraying a pre-heated detergent solution from the exterior of the washing drum through the perforations therein and onto the items of washing forming a ring of washing at the inner wall of the drum until they are saturated or below or until the formation of a free detergent solution is reported to a programme control unit;; d) during the spraying of the items of washing with hot or cold detergent solution, operating the washing drum at a speed of rotation which is below the centrifugal speed but above the usual speed of the apparatus; e) after the saturation of the items of washing with detergent solution has been reported, reducing the speed of the washing drum to loosen the items of washing from the drum wall, f) in the following washing operation, subjecting the loosened items of washing subjected to a mechanical action, and g) after each of the centrifugal operations ending the mechanical washing operation, operating the washing drum at a speed of the apparatus somewhat below the centrifugal speed and supplying rinsing water to the items of washing bearing against the drum wall by spraying in, likewise through the perforations in the washing drum.

3. A method as claimed in Claim 2, wherein a reheating of the detergent solution is effected after the saturation of the items of washing with detergent solution has been reported and before the speed of the drum is reduced.

4. A method as claimed in Claim 3, wherein the reheating step is effected by means of radiant heat or by means of hot air.

5. A method as claimed in Claim 3, wherein the saturation of the items of washing with detergent solution or rinsing water or the formation of a free detergent solution is monitored by a sensor or the like.

6. A method as claimed in Claim 2, characterised in that, when a free detergent solution is formed, this is recirculated to the washing by pumping.

7. An apparatus for carrying out a method of washing textiles in a drum-type washing machine as claimed in any one of Claims 1-6, wherein the perforations in the generated surface of the washing drum consist of punched holes with outwardly directed gill-plates achieved by stamping.

8. An apparatus as claimed in Claim 7, wherein the gill-plates are staggered.

9. An apparatus as claimed in Claim 7 or 8, wherein the gill-plates of one row are disposed extending in the diagonal direction in relation to the width of the drum wall.

10. An apparatus for carrying out a method of washing textiles in a drum-type washing machine as claimed in any one of Claims 1-6, wherein a heated water tank or an electric continuous-flow heater serves to heat up the water for the spraying operation.

1 1. An apparatus as claimed in Claim 10, wherein the heated tank or the electric continuous-flow heater for preparing the detergent solution to be sprayed is followed by a storage tank with which a spray-nozzle device directed onto the outer drum wall is brought into communication.

12. An apparatus as claimed in Claim 1 1, wherein a separate pump, a siphon or a wate'et pump serves to convey the detergent solution out of the storage tank to the spray-nozzle device.

13. A method as claimed in Claim 1 or 2, substantially as described herein.

14. An apparatus as claimed in Claim 7, substantially as described herein with reference to the accompanying drawing.