WO2002004734A1

WO2002004734A1 - Improvements in washing machines

Info

Publication number: WO2002004734A1
Application number: PCT/GB2001/002840
Authority: WO
Inventors: James Dyson; André Fraser MONTEIRO
Original assignee: Dyson Limited
Priority date: 2000-07-12
Filing date: 2001-06-26
Publication date: 2002-01-17
Also published as: AU2001266178A1; GB0017116D0; GB2364716A

Abstract

The invention provides a washing machine comprising a casing (12; 112) and a drum (20; 120) for containing articles to be washed, the drum (20; 120) having an outer wall (40; 140) and being mounted within the casing (12; 112) so as to be rotatable about a horizontal or substantially horizontal axis (26), and being water-retentive so that, in use, substantially all of the water used for washing the articles can be contained within the drum (20; 120), a water outlet (46; 146) being provided in the outer wall (40; 140) of the drum (20; 120) and being adapted so as to remain closed when, in use, the articles are being washed, characterised in that a water-receiving water passing through the water outlet (46) and the water-receiving channel (66) is open towards the drum (20). Alternatively, the water-receiving channel (66) is replaced by a watertight chamber (166) provided between the housing (112) and the drum (120) for receiving water passing through the water outlet (146). The invention also provides a method of utilising apparatus of the type mentioned above.

Description

Improvements in Washing Machines

The invention relates to improvements in washing machines.

A domestic washing machine normally consists essentially of a well-perforated, rotating drum into which textile articles to be washed are placed. The perforated drum is mounted inside a stationary, imperforate tank so that water and detergent introduced to the drum are retained within the tank but can pass freely and easily through the perforations into the interior of the drum so that the water levels within the drum and the tank are essentially the same at all times. The perforations are evenly spaced over the whole of the cylindrical surface of the drum. Textile articles to be washed are placed inside the drum and sufficient water and detergent is then introduced to the interior of the drum or tank so as to wet the articles thoroughly. Usually, a specific water level is required inside the drum and therefore in the tank as well. The water is heated to a predetermined temperature, normally selected by the user of the washing machine. The articles are then tumbled within the drum by rotating the drum at speeds of around 50 rpm in order to release dirt from, the fibres of the articles into the water. When the articles have been washed, the water is drained from the tank leaving the wet articles held within the drum. Fresh water is then introduced in order to rinse the articles and the drum is rotated again at similar speeds in order to release any detergent still held within the fibres of the articles. This rinsing process is repeated between two and four times. Each time the rinsing water is drained away from the tank leaving the wet articles held within the drum. When the rinsing process has been completed, the drum is rotated at a much higher speed (usually 800 to 1600 rpm) in order to extract most of the remaining water from the articles. The water is forced out of the drum through the perforations in the outer wall so that the water collects in the tank. The water which is spun out of the articles is pumped out of the tank as it accumulates. The articles, which iπii-t completely dry but have had nearly all of the water used to wash them spun out, can then be removed from the drum. Most of the water removed from the articles during spinning is pumped out of the drum before the drum slows down and stops.

There are a number of disadvantages of the conventional washing machine described above. One is the fact that the washing and rinsing cycles use significant amounts of water. This is due partly to the fact that the rotating drum of the machine sits inside a stationary tank which holds the water to be used. This means that there will be a space, normally annular, between the drum and the tank which must be partially filled with water in order to allow the water level in the drum to reach a specific height. The water which partially fills this space each time water is introduced to the drum is not utilised in the washing and rinsing procedure to the fullest extent possible. It is effectively extra water. However, the "extra" water still requires to be heated to the required temperature before washing because it circulates with the water which is actually used for the washing process. This heating of "extra" water consumes power and takes time which could ideally be saved. Time taken to fill the annular space with water prior to rinsing is also wasted. Another problem associated with the existence of this annular space is that detergent introduced into the tank rather than the drum can collect in the lower area between the drum and the tank wall. In some cases, the effectiveness of the detergent is reduced, sometimes quite seriously, during the washing process resulting in excessive use of detergent by the user or failure by the machine to wash articles to an acceptable standard.

Hitherto, it has been difficult for manufacturers to reduce the volume of the space between the drum and the tank because of the fact that washing machine drums are normally out of balance to a certain extent when they spin at high speeds. This causes vibrations which, whilst undesirable, are generally unavoidable. In order to allow for the vibrations to be present and to prevent the drum from colliding with the tank and causing damage to the machine, the drum is spaced sufficiently far from the tank for collisions to be avoided. This means that the space between the drum and the tank can never be reduced beyond that required to avoid collisions with the present general construction.

Some attempts have been made to retain most of the water used for washing and/or rinsing inside an imperforate drum in order to avoid the need to supply and heat "extra" water. Examples are shown in EP 0 381 423 A and GB 844,755. However, in each of these known arrangements, there is still a portion of the machine in which the wash action is not taking place but water is still present. Thus the amount of "excess" water is reduced, but not eliminated. Other proposals, based on different principles but designed to avoid the use of a tub and drum arrangement, are shown in GB 846,654, GB 578,637, DE 3 935 382, DE 4229 074, DE 3 822 725 and DE 4 310 006.

It is an object of the present invention to provide a washing machine which uses less water than conventional machines during the washing and/or rinsing cycles. It is another object of the present invention to provide a washing machine which consumes less power than known washing machines. It is a further object of the invention to provide a washing machine which takes a shorter time than is currently the norm to heat washing water to the required temperature. It is a still further object of the present invention to provide a washing machine in which the risk of detergent becoming lodged in the space between the drum and the tank is negated. It is a yet further object of the invention to provide a washing machine which makes full use of all of the available water available during washing and/or rinsing.

According to a first aspect of the invention, there is provided a washing machine comprising a casing and a drum for containing articles to be washed, the drum having an outer wall and being mounted within the casing so as to be rotatable about a horizontal or substantially horizontal axis, and being water-retentive so that, in use, substantially all of the water used for washing the articles can be contained within the drum, a water outlet being provided in the outer wall of the drum and being adapted so as to remain closed when, in use, the articles are being washed, characterised in that a water- receiving channel is provided radially outwardly of the water outlet for receiving water passing through the water outlet and the water-receiving channel is open towards the drum.

According to a second aspect of the invention, there is provided a washing machine comprising a casing and a drum for containing articles to be washed, the drum having an outer wall and being mounted within the casing so as to be rotatable about a horizontal or substantially horizontal axis, and being water-retentive so that, in use, substantially all of the water used for washing the articles can be contained within the drum, a water outlet being provided in the outer wall of the drum and being adapted so as to remain closed when, in use, the articles are being washed, characterised in that the drum is substantially enclosed by a housing so that a watertight chamber is provided between the housing and the drum for receiving water passing through the water outlet.

By the term "water-retentive", we mean that the drum is sufficiently impermeable to prevent water from passing freely and easily out of the drum during a normal washing operation. All of the water used for washing articles is retained in direct contact with the articles to be washed during a washing cycle.

The invention also provides a method of washing textile articles or the like utilising a washing machine according to any one of the preceding claims, the method comprising the steps of: a) introducing the textile articles to the interior of the drum; b) introducing water and detergent to the interior of the drum so that all of the said water and detergent is contained within the drum; c) rotating the drum at a speed sufficient to tumble the textile articles through the water and detergent whilst maintaining the said water outlet closed; d) subsequently causing the water outlet to open so as to allow water to pass out of the drum through the water outlet; and e) receiving the water leaving the drum via the water outlet in the water- receiving channel or the housing.

Further preferred and advantageous features are set out in the subsidiary claims.

Such an arrangement allows substantially all of the water required to wash the articles to be contained within the drum in which the articles are contained and used effectively in the washing process. This means that a smaller amount of water than is currently the norm is required to wash and rinse articles. This has the advantage of not requiring additional water to fill the space between the drum and the tank, or the spaces around any water extraction means of the sort contemplated in the prior art, which means that no "wasted" water requires to be heated. This reduces the time taken to fill the machine drum to the required level and to heat the water to the required temperature with consequential energy and time savings. Also the risk of detergent getting trapped and remaining unused in the said space can be negated.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein:

Figure 1 is a schematic cross-sectional side view through a first embodiment of a washing machine according to the invention;

Figure 2 is a front view of the interior of the apparatus of Figure 1, omitting the casing for clarity;^'

Figure 3 a is an enlarged side view of a seal arrangement forming part of the washing machine of Figures 1 and 2;

Figure 3b is an enlarged side view of a valve forming part of the washing inachine of Figures 1 and 2; Figure 4 illustrates an alternative cross-sectional shape of the drum illustrated in Figure 2; and

Figure 5 is a schematic cross-sectional side view, similar to the view of Figure 1, through a second embodiment of the invention.

A washing machine according to the invention is illustrated in Figures 1 and 2. As is conventional, the washing machine 10 comprises a generally rectangular outer easing 12 having support feet 14 and a door 16 located in the front wall of the casing 12 which is hinged at one side and has a releasable catch-type handle 18 at the other side. The door 16 is arranged so as to sealingly engage with the casing 12 around its periphery when in its closed position. Seal 22 is provided between the door 16 and the casing 12 for this purpose. A drum 20 is rotatably mounted within the casing 12. In a conventional machine, the drum 20 would be surrounded by an imperforate tank and the door would sealingly engage with the tank. In the illustrated machine according to the invention, there is no imperforate tank and the door 16 is therefore sealingly engaged with the drum 20. Seal 24 is provided for this purpose. Seal 24 is a rotary seal which will allow the drum 20 to rotate with respect to the door 16 without permitting any water contained within the drum 20 to leak out.

Figure 3 a illustrates an appropriate seal arrangement, although it is to be understood that different types of rotary seal will be equally suitable. The seal 22 is mounted on the door 16 around its outer periphery and is shaped to cooperate with an arcuate edge of the casing 12. The rotary seal 24 is mounted on an inner lip portion 16a of the door 16 and comprises an annular, resilient, inwardly-projecting tongue 24a having a smoothly contoured distal end. The distal end of the tongue 24a engages with and abuts against a smoothly-contoured recess 25 in a front lip 44 of the drum 20. The recess 25 is also annular and the arrangement allows the seal 24 to slide within the recess 25 as the drum 20 rotates with respect to the casing 12. Seals of this type are commercially available and will be known to a skilled reader.

The drum 20 is generally cylindrical in shape, although the exact preferred shape will be described in more detail below. The drum 20 is mounted for rotation about a longitudinal axis 26 and has a shaft 28 extending along the axis 26 away from the side of the drum 20 remote from the door 16. The shaft 28 is mounted on bearings 30 to support the drum 20 and to allow the drum 20 to rotate. A motor 32 is provided which is arranged to rotate the drum 20 about the axis 26. The motor 32 is capable of rotating the drum 20 about the axis 26 at different speeds in the normal way required by washing machines. Further discussion of the operation of the motor 32 is not beneficial and will therefore not be given here.

The shaft 28 comprises a water inlet conduit 34 which can be formed merely by making the shaft 28 hollow or else the shaft 28 can carry a tube or pipe (not shown) capable of remaining stationary whilst the drum 20 rotates about its axis. Merely mounting such a pipe inside the shaft by way of a simple bearing would be sufficient since the pipe would be required to carry no load and would not itself rotate. The water inlet conduit 34 is directly connected or connectable to a mains water supply in the domestic environment, as is required for any domestic washing machine. This inlet conduit 34 forms the inlet via which water is introduced to the drum 20 when washing or rinsing is to be carried out. Alternatively, water can be introduced to the interior of the drum 20 via an inlet 34a (see Figure 2) consisting of a pipe or tube mounted in the door 16 or the seal 24 and connected to a water supply conduit (not shown) within the casing 12, which conduit will be connected in turn to a mains water supply in the normal way. A heater 36 is arranged within the casing 12 for heating the water entering the machine to the required temperature when necessary. Alternatively, a heating arrangement for heating the water after it has entered the drum 20 can be provided in a known manner. The drum 20 is generally cylindrical in shape. It comprises an outer wall 40, a rear wall 42 and a front lip 44. The rear wall 42 defines and closes the rear of the drum 20 and is circular in shape. The shaft 28 is mounted to the rear of the rear wall 42 which has an aperture therein to allow water passing along the water inlet conduit to enter the interior of the drum 20. The outer wall 40 extends between the outermost edge of the rear wall 42 and the front lip 44. The front lip 44 extends parallel to the rear wall 42 but is generally annular in shape so that the door 16 can sealingly engage with the inner edge of the front lip 44 as described above. When the door 16 is sealingly engaged with the inner edge of the front lip 44, the drum 20 is closed at the front.

The outer wall 40 extends between the rear wall 42 and the front lip 44 to form a generally cylindrical drum 20. However, the outer wall 40 is formed from two frusto- conical portions 40a, 40b which increase in diameter as they approach one another. The angle of inclination of the frusto-conical portions 40a, 40b need only be very slight, ie. of the order of 1° to 5°, preferably around 3°. Consequently, the outer wall 40 has a maximum diameter at the circumference at which the frusto-conical portions 40a, 40b meet. In the drawings, the frusto-conical portions 40a, 40b are shown as being of similar dimensions but this is not necessary. The frusto-conical portions 40a, 40b can be dimensioned so that the circumference of maximum diameter is closer to either of the ends of the drum 20 if desired. It is envisaged that physical constraints within the casing 12 will assist in determining the desired position of the circumference of maximum diameter for any given machine.

The outer wall 40 of the drum 20 is imperforate. Water cannot travel through the wall of the drum 20 from the interior of the drum 20 to the exterior except through the valves 46 described below.

A plurality of valves 46 are spaced about the circumference of maximum diameter of the outer wall 40 of the drum 20. In the illustrated embodiment, eight valves 46 are shown but the number of valves can be varied as required. Preferably, the valves 46 are equispaced about the circumference of maximum diameter of the outer wall 40 as shown. Further details of the preferred form of the valves are shown in Figure 3b.

Essentially, each valve 46 consists of an aperture 48 closed by a valve member 50 so as to prevent water from passing through the aperture 48. Each aperture 48 is located in the outer wall 40 of the drum 20 at the point where the frusto-conical portions 40a, 40b meet. The valve member 50 comprises a stopper 52 which is located within a housing 60. The housing 60 is generally cylindrical and has cylindrical side walls 60a and an end wall 60b remote from the outer wall 40 of the drum 20. The end wall 60b has apertures 60c arranged therein. An axial compression spring 62 bears against the end wall 60b and biases the stopper 52 towards the outer wall 40 of the drum 20 so that the stopper 52 is biased into the aperture 48. The distal end of the stopper 52 lies flush with the interior surface of the outer wall 40 of the drum 20 when the valve 46 is in the closed position.

When the drum 20 is rotated at high speeds, the valves 46 are also rotated with the drum 20 at the same high speeds. Each valve 46 will open as soon as the centrifugal forces acting on the respective stopper 52 exceed the force of the compression spring 62 which acts so as to bias the stopper 52 into the aperture 48. As soon as the stopper 52 is moved out of the aperture 48 in the direction of the arrow 64, water is able to flow through the aperture 48, through the apertures 60c and out of the drum 20.

The drum 20 illustrated in Figure 2 has a circular cross-section at all points along its length. This is adequate provided that there are sufficient apertures 48 spaced around the circumference of maximum diameter. If desired, or if it proves necessary through having fewer apertures 48, the outer wall 40 of the drum 20 can be shaped so that the apertures 48 are spaced further from the longitudinal axis 26 than the remainder of the outer wall 40 along the circumference of maximum diameter. A suitable shape is shown in Figure 4. As can be seen, the drum 20 is shaped so that, in the region of the circumference of maximum diameter, the outer wall has a polygonal shape. In the Figure, the outer wall 40 is octagonal. The valves 46 are positioned at each of the eight corners of the circumference. The frusto-conical portions 40a, 40b are each shaped to give a circumference of maximum diameter of this shape. It is perfectly possible for the frusto-conical portions to be essentially cylindrical away from the polygonal circumference of maximum diameter, but equally it is possible for the polygonal cross- section to be continued away from the circumference of maximum diameter. Thus different shapes of drum are possible within the normal confines of washing machines.

Arranged radially outwardly of the circumference of maximum diameter of the drum 20 is an annular channel 66. As can be seen from Figures 1 and 2, the annular channel 66 is generally U-shaped, having side walls extending towards the drum 20 and a bottom wall opposite the valves 46 and closing the channel 66. The channel 66 is open on the side facing the drum 20. The channel 66 extends around the drum 20 on either side thereof from the top down to a point substantially level with the bottom of the drum 20. A trough 68 is positioned below the drum 20. The trough 68 extends sufficiently far to either side of the drum to overlap with the annular channel 66 as shown in Figure 2. The volume of the trough 68 is sufficient to hold the maximum amount of water likely to be spun out of a load of washing during a spin cycle when the washing machine is in use. This could be approximately 10 to 15 litres. A conduit 70 leads from the trough 68 to a drain via a pump 72. The pump is powered via the motor 32.

The washing machine 10 illustrated in the drawings and described above operates in the following manner. Clothes or other textile articles to be washed are placed in the drum 20 by way of the door 16. The door 16 is then closed so that the seals 22, 24 are effective to seal the drum 20 and ensure that it is watertight. Water for washing is then introduced via the water inlet conduit 34 (or via the inlet 34a) to wet the articles to be washed and to fill the drum 20 to the desired level. The water which is introduced to the drum 20 can be heated by the heater 36 as it enters the drum 20, or it can be heated after it has entered the drum 20 by other heating means (not shown). Because the drum 20 is imperforate and the valves 46 are closed, all of the water used for washing is contained within the drum 20. There is no annular space between the drum 20 and an external tank which requires to be filled and therefore no "wasted" water requiring to be pumped in and heated. The saving in water, filling time, heating time and heating energy is considerable.

Detergent is introduced to the interior of the drum 20 in any one of a number of conventional ways. A soap tray can be provided, or else the user can place detergent into the interior of the drum 20 by way of tablets, detergent balls or other means. In any event, detergent is introduced to the interior of the drum 20 before the washing cycle commences. The washing cycle consists of short periods of slow rotation of the drum 20 at speeds of around 50 rpm. Consecutive periods of rotation are in opposite directions if desired. During these periods of rotation, the articles to be washed are tumbled within the drum 20 so that they are agitated against one another. This agitation releases dirt from the fibres of the articles into the water. This cycle lasts between 10 and 20 minutes.

Once the articles within the drum 20 have been washed, the washing water is required to be removed from the drum 20. In-order to achieve this, the drum 20 is rotated at a higher speed than is used during the washing cycle. At speeds above about 60 rpm the articles are held against the wall 40 of the drum 20 and the water held within the fibres of the articles is flung against the wall 40. The centrifugal forces acting on the stoppers 52 of the valves 46 causes the valves 46 to open and the water passes towards and through the apertures 48. As the drum 20 is still spinning, the water is flung away from the drum 20 and into the annular channel 66 where it drains down to the trough 68. The water collects in the trough 68 from where it can be removed by the pump 72 via the conduit 70 to a drain.

When sufficient water has been removed from the drum 20, the drum 20 is slowed to a stop. Clean water is then introduced to the drum 20 via the water inlet conduit 34 (or inlet 34a) to rinse the articles held within the drum 20. The rinsing water does not need to be heated, but there is still a water saving because no annular space between a tank and the drum requires to be filled. The filling time is therefore shortened and the total water consumption is reduced. The drum 20 is again rotated at slow speeds for short periods to agitate the articles so as to release detergent retained within the fibres of the articles into the water. When this has been completed, the water is again removed from the drum 20 in the same way, ie by raising the rotational speed of the drum 20 above 60 rpm and allowing the water to pass through the apertures 48 when the valves 46 are opened. The water is collected in the trough 68 and removed via the conduit 70. This rinsing process is repeated as often as necessary, normally between two and four times.

When the articles have been fully rinsed, the rotational speed of the drum 20 is increased to the required spirining speed, normally between 800 and 1600 rpm. Any water remaining within the fibres of the articles is flung towards the wall 40 of the drum 20 under the centrifugal forces caused by the rotation of the drum 20. The valves 46 open under the action of the centrifugal forces and the water is again allowed to pass through the valves 46, into the annular channel 66 and then into the trough 68. At the end of the spinning cycle, the washed and spun articles can be removed from the washing machine 10 via the door 16.

In this way, the normal cycles of a washing machine can be carried out in the absence of a separate tank surrounding the drum in which the articles to be washed are placed. There is therefore no annular space surrounding the drum which requires to be filled with water before washing or rinsing can take place. There are consequential savings to be made in the time taken to fill the drum to the desired level, to heat the water to the desired temperature and to empty the drum. The potential savings in water consumption and power consumption are also considerable. In the event that slight leakage occurs through the valves during the washing and rinsing cycles, the leaked water is caught by the annular channel and collected in the trough. It is envisaged that the rate of leakage, even in the worst cases, will be small enough not to reduce the quantity of water in the interior of the drum to any significant extent. A second embodiment of the invention is shown in Figure 5. As before, the washing machine 100 illustrated has a generally rectangular outer casing 112 with support feet 114 and a door 116 mounted in the front of the casing 112. The door 116 is hinged on one side and has a catch-type handle for opening the door 116 on the other side. A drum 120 is mounted inside the casing 112 and is rotatable by means of bearings 130 about a shaft 128 fixed to the rear wall of the casing 112, or alternatively to a frame of the machine. The drum 120 is constructed as described above in relation to the embodiment shown in Figures 1 and 2 and has an outer wall 140 made up of two frusto-conical portions 140a, 140b which meet at a circumference of maximum diameter. The drum 120 is imperforate and valves 146 are equispaced about the circumference of maximum diameter.

Arranged radially outwardly of the drum 120 is an imperforate housing 166 which surrounds and encloses the drum 120. The housing 166 is sealed against the door 116 when the door 116 is closed by means of the seal 124. The drum 120 is sealed against the housing 166 by way of a rotary seal 125 which can be similar to the rotary seal 24 illustrated in Figure 3a and described above. A watertight chamber 167 is thereby created between the drum 120 and the housing 166. The drum 120 is also watertight when the door 116 is closed. The chamber 167 has a lower wall 168 which slopes towards a central area in which an outlet 170 is located. The outlet 170 consists of a conduit which leads to a two-way valve 171. From one side of the two-way valve 171 , a first conduit 173 a leads to a drain outlet 174 via a first pump 172a. From the other side of the two-way valve 171, a second conduit 173b leads to a drum inlet 134 via a second pump 172b. The inlet 134 is located in the door 116 or the seal 124 and is arranged to introduce water into the interior of the drum 120. The conduit 173b comprises a flexible pipe at least in the area of the door hinge to allow the door 116 to be easily opened and closed without dislodging or affecting the performance of the inlet 134. A water inlet 135 is arranged in the casing 112 and adapted so as to be connectable to a mains water supply, as is conventional in washing machines. The water inlet leads to a soap tray 180 for receiving and holding soap powder for use in the washing machine. The soap tray has an outlet 182 leading directly to the chamber 167 between the housing 166 and the drum 120 for purposes which will be described below.

A motor 132 is provided in the casing 112 and is connected to the drum shaft 128 to cause the drum 120 to rotate at different speeds as is normally required for washing machines. The motor 132 is also arranged to drive the first and second pumps 172a, 172b in the manner described below. The pumps 172a, 172b could equally be driven separately from the drum.

The housing 166 replaces the annular channel 66 and trough 68 illustrated in Figures 1 and 2 and described above. However, its function is exactly the same as the channel 66 and trough 68 for the purposes of removing water from the interior of the drum 120 when required. As before, when the annular velocity of the drum 120 is sufficient to open the valves 146, water will pass through the apertures in the drum 120 and then into the chamber 167 which will collect the water which has left the drum 120. The water will collect, inevitably, in the lower portion of the chamber 167 and, when the collected water is required to be removed from the washing machine, the valve 171 is positioned so as to open the conduit 172a to the outlet 170 and the first pump 172a is operated so that water is directed from the chamber 167 to the drain outlet 174. Thus the drum 120 can be emptied of water which has been spun out of the textile articles which are being washed.

The arrangement shown in Figure 5 has an important advantage over that shown in Figures 1 and 2. The advantage relates to the step of introducing water and detergent into the machine. When the textile articles have been placed in the drum 120, water is introduced to the machine 100 via the inlet 135. The water passes to the sb'ap tray 180 in which soap powder has been placed by the user. The flow of the water carries the soap powder into tne chamber 167 between the housing 166 and the drum 120. Slow rotation of the drum 120 at this stage causes the soap powder (detergent) to be mixed thoroughly with the water which will then be used for washing. There can be no significant risk that there will be any failure of the soap powder to be used in the washing cycle or that lumps of the powder will accumulate in the lower area of the chamber 167. Use of soap powder is thus optimised and the water/detergent mixture subsequently introduced to the drum 120 in order to carry out the washing process is well mixed and ready for use. Heating by way of a heater 136 can also take place during the mixing cycle.

Once the soap powder has been mixed with the water, the two-way valve 171 is positioned so as to open conduit 173b and pump 172b is operated. This removes the water/detergent mixture from the chamber 167 and passes it through the conduit 173b and the inlet 134 into the interior of the drum 120. The water passes through a filter 175 positioned in the conduit 173b so that any large particles entrained within the water are removed. This step can take place either whilst the drum 120 is stationery or whilst the drum 120 continues to rotate at the slow speeds achieved during mixing of the water and detergent. The washing cycle then proceeds as described above in relation to Figures 1 and 2, but with the water removed from the drum 120 being collected in the chamber 167 instead of the channel 66 and trough 68. When the water collected in the chamber 167 is to be drained away, the valve 171 is positioned so that the conduit 173a is opened and the pump 172a is operated so that the water in the chamber 167 is passed to the drain 174. Also, if any minor leakage occurs through the valves 146 during any of the washing and rinsing cycles, the pump 172b returns the leaked water to the interior of the drum 120.

The invention is not limited to the precise embodiment illustrated in the drawings and described above. Many modifications and variations will be apparent to a skilled reader. For example, the design and construction of the valves 46 can be varied to Suit specific needs and requirements and different arrangements will be suitable. All that is required is a valve which will open when the water is required to be removed from the drum. Alternative designs of valve which will open under the action of centrifugal forces at specific spin speeds are equally as acceptable as the design illustrated in Figure 3b. A similar effect can be achieved using control techniques which detect the spin speed of the drum and are activated when, for example, the speed of rotation of the drum reaches a predetermined value. Other modifications are also within the scope of the invention, for example providing sufficiently small perforations in the drum to allow water to be retained within the drum at low rotation speeds but to be spun out of the drum during a spinning cycle.

Claims

Claims:

1. A washing machine comprising a casing and a drum for containing articles to be washed, the drum having an outer wall and being mounted within the casing so as to be rotatable about a horizontal or substantially horizontal axis, and being water-retentive so that, in use, substantially all of the water used for washing the articles can be contained within the drum, a water outlet being provided in the outer wall of the drum and being adapted so as to remain closed when, in use, the articles are being washed, characterised in that a water-receiving channel is provided radially outwardly of the water outlet for receiving water passing through the water outlet and the water-receiving channel is open towards the drum.

2. A washing machine comprising a casing and a drum for containing articles to be washed, the drum having an outer wall and being mounted within the casing so as to be rotatable- about a horizontal or substantially horizontal axis, and being water-retentive so that, in use, substantially all of the water used for washing the articles can be contained within the drum, a water outlet being provided in the outer wall of the drum and being adapted so as to remain closed when, in use, the articles are being washed, characterised in that the drum is substantially enclosed by a housing so that a watertight chamber is provided between the housing and the drum for receiving water passing through the water outlet.

3. A washing machine as claimed in claim 1 or 2, wherein, apart from the water outlet, the drum is substantially imperforate.

4. A washing machine as claimed in claim 3, wherein the water outlet consists of a plurality of apertures spaced around the cylindrical outer wall of the drum.

5. A washing machine as claimed in claim 4, wherein each aperture is closed by a valve adapted to remain closed during a washing cycle.

6. A washing machine as claimed in claim 5, wherein each valve is adapted to open during a spinning cycle.

7. A washing machine as claimed in claim 6, wherein each valve comprises a biasing portion for biasing the valve into a closed position, the biasing portion being located so as to be exposed to water contained within the drum during a spinning cycle.

8. A washing machine as claimed in claim 7, wherein the biasing portion comprises a spring-loaded stopper located so as to close the respective aperture.

9. A washing machine as claimed in any one of claims 4 to 8, wherein the apertures are spaced radially further from the axis than the remainder of the outer wall of the drum.

10. A washing machine as claimed in claim 1 and any one of claims 3 to 9, wherein a water-collecting trough is provided for collecting water received by the water- receiving channel.

11 A washing machine as claimed in claim 10, wherein a pump is provided for removing water from the water-collecting trough.

12. A washing machine as claimed in any one of claims 1 to 11, wherein a water inlet is provided, the water inlet being concentric with the axis about which the drum is rotatable.

13. A washing machine as claimed in any one of claims 1 to 11, wherein the drum is delimited in part by a door via which articles to be washed can be introduced to the interior of the drum, and a water inlet is provided, the water inlet being located in the door.

14. A washing machine as claimed in claim 2 and any one of claims 3 to 9, wherein a pump is provided for removing water from the watertight chamber.

15. A washing machine as claimed in claim 14, wherein a water inlet is provided, the inlet communicating with the watertight chamber.

16. A washing machine as claimed in claim 15, wherein the water inlet is arranged to pass water through a soap tray.

17. A washing machine as claimed in claim 15 or 16, wherein a conduit is provided between the watertight chamber and the interior of the drum to allow water to be passed from the chamber to the drum.

18. A washing machine as claimed in claim 17, wherein a pump is provided in the said conduit.

19. A washing machine substantially as hereinbefore described with reference to any of the embodiments shown in the accompanying drawings.

20. A method of washing textile articles or the like utilising a washing machine according to any one of the preceding claims, the method comprising the steps of: a) introducing the textile articles to the interior of the drum; b) introducing water and detergent to the interior of the drum so that all of the said water and detergent is contained within the drum; c) rotating the drum at a speed sufficient to tumble the textile articles through the water and detergent whilst maintaining the said water outlet closed; d) subsequently causing the water outlet to open so as to allow water to pass out of the drum through the water outlet; and e) receiving the water leaving the drum via the water outlet in the water- receiving channel or the housing.

21. A method as claimed in claim 20, wherein the water outlet is caused to open under centrifugal forces created by rotation of the drum above a predetermined speed.

22. A method as claimed in claim 21, wherein the predetermined speed at which the water outlet is caused to open is greater than lOOrpm.

23. A method as claimed in any one of claims 20 to 22, further comprising the step of mixing the water and detergent together before introducing them to the interior of the drum.

24. A washing machine as claimed in any one of claims 20 to 23, further comprising the step of rinsing the textile articles subsequent to washing by: a) introducing clean water to the interior of the drum so that all of the said water is contained within the drum; b) rotating the drum at a speed sufficient to tumble the textile articles through the water whilst maintaining the said water outlet closed; c) subsequently causing the water outlet to open so as to allow water to pass out of the drum through the water outlet; and d) receiving the water leaving the drum via the water outlet in the water- receiving channel or the housing.

25. A method as claimed in claim 24, wherein the rinsing step is repeated between two and four times.

26. A method as claimed in any one of claims 20 to 25, further comprising a spinning step in which the drum is rotated at a speed of between 800 and 2000 rpm.

27. A method of washing textile articles or the like substantially as herein before described with reference to any of the embodiments shown in the accompanying drawings.