Improved Dishwasher and Fluid Dispensing Means

The invention to which this application relates a fluid dispensing means which has, although not necessarily exclusively, the ability to improve the utilisation in a dishwasher, either domestic or industrial versions . The improvement allows the improved dispersion of fluid throughout the dishwasher cabinet. Cabinet is the term used herein to describe the housing which defines the internal cavity within which the utensils to be washed are stacked, typically, but not necessarily exclusively, in coated wire trays and in which cavity the fluid is to be dispersed.

In normal usage, conventional dishwashers incorporate one or more arms, referred to as spray arms, which are provided to rotate about an axis, the said axis is typically a common vertical axis for all of the arms at the centre of the cabinet. As the spray arms rotate, cleaning fluid such as water, or water and detergent, is deposited from the same via a number of spaced outlets, provided along the length of the arms. The outlets are spaced and shaped to improve the dispensation of the fluid and are fixed with respect to the spray arm.

A problem with conventional dishwashers is that the fluid is dispersed from the spray arm outlets in a fixed circular path as the arm rotates. This therefore means that while the number of outlets, and the spacing of them, can be selected to provide an optimum pattern, it is still not possible to ensure that all utensils within the dishwasher can be covered or washed effectively and uniformly. A further problem is that the spray arms can become trapped or snagged and hence are prevented from rotating, typically by an item of cutlery protruding, a pan lid protruding or the like. The spray arm is then, for the duration of that wash cycle, held in the same position and so fluid will only be deposited at a series of fixed locations which,

in turn, means that the remaining utensils will not be washed properly.

EP 1010390 discloses a rotatable assembly for use in a spray arm for a dishwasher. The assembly includes a rotatable member with a channel through which fluid passes. The member includes a vane which protrudes from the assembly. However the use of the vane and the assembly is generally problematic and the assembly is subject to drainage and/or malfunction.

US6263888 discloses an arrangement whereby the disposal of fluid within the cabinet is monitored and a chaotic disposal pattern according to specific parameters is required to be achieved and controlled.

US2004/ 195361 relates to the provision of a rotatable arm . which is mounted to rotate wit respect to a rotatable spray arm. However the provision of these additional arms means that the same protrude and reduce the available utensil space in the cabinet and are susceptible to damage.

EP l 365079 discloses a nozzle assembly in which there is provided a nozzle mounted in a housing. The introduction of fluid into the housing causes the rotation of the nozzle. The nozzle is mounted so that the axis of rotation of the same is offset from the centre axis of the hole through which the nozzle protrudes to provide a specific spray pattern of fluid from the nozzle.

The aim of the present invention is to provide improved apparatus for the dispersal of fluid in a dishwasher to provide improvements in the repeatability of the washing action in that the cleaning performance of the dishwasher is repeated more

reliably on each washing cycle and provides a wider spread of the distribution of the fluid throughout the dishwasher cabinet.

In a first aspect of the invention there is provided a dishwasher, said dishwasher having a cabinet in which items to be washed are placed and, in said cabinet, there is provided at least one spray arm, said spray arm including one or more outlets through which fluid is dispersed to aid the washing of the items and is provided to be rotatable about an axis of rotation and wherein at least one of the outlets is provided in a rotatable member, mounted in the spray arm said member rotatable about an axis which is spaced from but parallel with the axis of rotation of the spray arm.

In one embodiment the member is rotatable when fluid is supplied to the same.

In one embodiment the rotatable member has at least one channel therein. In one embodiment the channel leads from a first side of the member and passes through to a second, opposing side of the member to allow the passage of the fluid therethrough. Typically, the channel is provided to allow the flow of fluid. In one embodiment at least one channel is positioned and/or shaped so as to cause the flow of the fluid to also cause the member to rotate as the fluid flows through the channel.

Typically, the said rotatable member is provided as part of an assembly which includes a housing or race and the race is provided with a port which allows the fluid to pass through the same and then flow into the channel in the rotatable member. In one embodiment the opening into the channel is partially offset from the exit of the port to improve the ability for the

flow of fluid to cause the member to rotate with respect to the housing.

In one embodiment, the spray arm is provided with an aperture for the reception of a rotatable assembly having located therein at least one rotatable member and in communication with the fluid supply in the spray arm.

In a further embodiment, the said spray arm includes a series of rotatable members at spaced locations which are spaced from the axis of rotation of the spray arm. In one embodiment one of the rotatable assemblies may be provided at the rotational axis of the spray arm.

In one embodiment, the said fluid flows upwardly from the spray arm.

Typically the said rotatable members in the assemblies mounted on the spray arms are orientated so as to rotate about a substantially vertical axis. However, to suit particular requirements the said angle of orientation of the axis with respect to the spray arm can be selected so as to allow the optimum or desired dispersion of fluid from the rotatable members and hence the spray arms. In addition or alternatively the assembly itself can be adjusted to change the angle and/or the angle of the channel within the member can be altered to achieve the required dispersion of fluid.

Thus, in accordance with this aspect of the invention, the fluid is dispersed, firstly with respect to the rotation of the spray arm with respect to the spray arm axis of rotation in the dishwasher cabinet and secondly with respect to the rotation of the rotatable members with respect to the spray arm, said rotatable

members rotated by the movement of the fluid through the same.

In whichever embodiment, it is envisaged that the interior of the spray arm will have one or more ducts for the supply of fluid to each of the rotatable member and that the supply of the fluid into the duct in the spray arm will be provided in a conventional manner.

Within the spray arm there can be provided a single duct or alternatively, a series of smaller ducts can be provided each duct leading to a particular rotatable member or other form of outlet and it will therefore be appreciated that a person skilled in the art, will be readily able to form the duct or ducts in the spray arm accordingly to provide the optimum flow of fluid.

In a further aspect of the invention there is provided a rotatable assembly in connection with a fluid supply to allow fluid to be . introduced from the assembly in a pattern, said assembly introducing a housing with a port through which fluid enters the assembly and passes into at least one channel provided in a member which is rotatable with respect to the housing and from which channel the fluid exits the assembly and wherein said channel has a longitudinal axis which is offset to the axis of rotation of the member.

Typically the face of the member from which the fluid exits the channel is substantially planar with no protrusions.

In one embodiment the port in the housing is positioned at the axis of rotation of the member and therefore partially offset with respect to the channel inlet but still allowing the passage of fluid from the port and into the channel to create rotation of the member. In one embodiment the channel longitudinal axis is at

an angle to the axis of rotation of the member, typically an acute angle.

In one embodiment the rotatable assembly includes a plurality of channels provided in the member. In one embodiment the plurality of channels lead from a common port, with the exits from the channels spaced on the external surface of the member.

Typically, the rotatable member is mounted within a housing which acts as a race, said race provided with a port through which the fluid passes into the channel in the rotatable member, said fluid passing through the channel and leaving the channel as the rotatable member rotates. Typically the channel in the member is formed so as to cause the member to rotate as the fluid passes therethrough. In one embodiment there is provided a stepped portion at the interface between the port and channel as an anti-clogging feature and a cage may also be provided in accordance with the applicant's patent application US2004/0071375 to prevent clogging by debris.

In a further aspect of the invention there is provided a dishwasher having a plurality of fluid outlets for dispensing fluid into the dishwasher cabinet, and wherein at least one of said outlets is provided by an assembly including a member which is rotatable to dispense fluid therefrom, into the cavity, said member having at least one channel passing between opposing first and second sides of the member, wherein said channel has a longitudinal axis, which is angularly offset to the axis of rotation of said member.

Thus, in this embodiment, the fluid enters the cabinet from each channel outlet in a path which allows the fluid to flow onto more than one particular location within the cabinet as the member of each assembly rotates . Typically, in whichever of

the aspects and embodiment herein described, the rotatable member rotates under the force of fluid passing through the channel therein and therefore no power or drive means is required to be provided to the rotatable member other than the supply of the fluid itself.

In one embodiment the rotatable assemblies are located in any or any combination of the walls, floors or ceilings of the cavity of the dishwasher and at selected positions, typically to maximise the spread and cleaning action of the fluid on the items in the dishwasher. The same can also be directed to areas within the cabinet which previously would have been difficult to access with conventional fluid spray means.

In one embodiment, no or a reduced number of spray arms are required.

Typically, the rotatable member can rotate under a relatively low pressure and low flow rate of fluid thereby ensuring that the rotation of the member will occur under normal dishwasher fluid supply and pressure conditions.

Typically, the assemblies are provided at selected locations on the walls and/or spray arms of the dishwasher.

Specific embodiments of the invention are now described with reference to the accompanying drawings, wherein:-

Figure I a illustrates a rotatable assembly for use in the invention in accordance to one embodiment;

Figure I b illustrates an alternative embodiment of a rotatable assembly;

Figures 2a and 2b illustrate the incorporation of a rotatable member in spray arms in a dishwasher cabinet in accordance with one embodiment of the invention; and

Figure 3 illustrates the incorporation of rotatable members in a dishwasher cabinet in accordance with a further embodiment of the invention.

Referring firstly to Figure I a, there is illustrated a rotatable member which can be used in accordance with the invention in one embodiment. The rotatable member incorporates a race which is a housing 2 having side walls 4 which engage a rotatable member 14 therein and a face 6. The face 6 is provided with a shaped port 8 through which a fluid supply can enter as indicated by arrow 10. The angle of supply of the fluid can be provided to suit optimum conditions and flow rate. The fluid which enters the port passes through the same to reach a channel 12 provided in the rotatable member 14. The channel has a longitudinal axis 15 which is offset from the axis 16 about which the rotatable member rotates. The offsetting of the channel 12 and the straight shape of the same means that the fluid can still easily pass through the channel to exit and be dispersed from the rotatable member in a path illustrated by the broken lines 20 and arrow 31. Furthermore, as the fluid passes through the rotatable member, it acts as a drive means to cause the member to rotate about the axis 16 which in turn causes the path of dispensation of the fluid to be achieved.

In Figure Ib a similar rotatable assembly is shown and the same reference numerals are used as appropriate. However, in this case, two channels are provided 12, 12', both fed with fluid from port 8, but leading to spaced openings 21 on the face 19 of the member 14. In practise this can be used to increase fluid flow

from the assembly. Also, although two channels are shown any suitable number can be used to suit specific requirements.

In each case, the rotatable members dispense fluid in a substantially circular path when rotated and the external face 19 of the member 14 has no protuberances such as veins as none are required for the direction of fluid or to cause rotation of the member.

Figure 2a illustrates a dishwasher cabinet 32 of a conventional form, the dishwasher cabinet having a first upper tray 34 and a second lower, spaced tray 36, each provided for the reception of items 38 therein to be washed within the cabinet. Also provided can be one or more spray arms 40, 42 (in this case two are shown) each mounted for rotation about a vertical axis 44 as shown so as to allow the dispensation of fluid through the spray arms and onto the utensils held in the trays . The remainder of the operation of the dishwasher in terms of the washing is not described in detail as the same general operation will occur as with conventional dishwashers. However, in each of the spray arms, there is provided one or more rotatable members in accordance with the invention and the upper side 46 of one of such spray arms is shown in detail in Figure 2b.

In use, the fluid to be supplied into the dishwasher cabinet, passes through the interior of the spray arm 42 along a series of ducts (not shown), the ducts leading respectively to one or a number of the rotatable members from a centre supply funnel 50 so as to supply fluid for dispensation through the rotatable members 14 in the manner described in Figure 1. Thus, in accordance with this embodiment of the invention, the fluid is dispensed in a rotating manner as indicated by arrow 52 from each of the rotatable member channels 12 and each of the rotatable members is rotated about their own axis of rotation 16

and the assemblies also move in a circular path 54 due to the rotation of the spray arm about axis 44. It is therefore shown how the rotational axes 16 of the rotatable assemblies are offset and spaced from the spray arm axis of rotation 44.

It will therefore be appreciated that due to the dual rotation formation which is achieved, i.e rotation of each member about its axis 16 and the spray arm about axis 44, the dispensation of the fluid within the cabinet is greatly improved such that a greater proportion of the utensils, when held within the trays, will be directly contacted by dispensed fluid than is the case in the conventional systems wherein the dispensed fluid only pas ses in a first rotational path caused by the rotation of the spray arms, as outlets are conventionally in a fixed position on the spray arms. The fact that the rotational members are self rotating inasmuch that the passage of the fluid causes the rotation, means that no additional drive or power is required thereby the improvement is obtained without the need to complicate or add to the expense of the dishwasher.

Figure 3 illustrates an alternative embodiment wherein rather than spray arms being provided at all or, alternatively, in addition to spray arms being provided, the rotatable assemblies of Figure 1 can be positioned in the walls 58, base 60 or top face 62 of the dishwasher cabinet as shown at spaced locations. In this embodiment, the fluid is supplied behind the walls of the cabinet to the assemblies to pass from the ports and into the channels in the members 14 thereby causing the same to rotate and hence the fluid to be dispensed through the channels in a path 64 into an area of the dishwasher cavity in the cabinet. In this embodiment, there is therefore the advantage that the spray arms need not be provided at all and hence the disadvantages of the spray arms being liable to snagging are minimised as the water is still dispensed in a circular path as the members rotate.

A further advantage of this particular embodiment is that as spray arms are not provided the same need not be attached to the trays and hence, rather than the trays being required to be unloaded, once the utensils are cleaned, the trays themselves can be removed from the dishwasher and placed into, for example, a drawer and simply removed from the trays in the drawer when the same are required to be used. This would allow further empty trays to be inserted into the dishwasher for the reception of the further utensils and therefore it will be appreciated that because the spray arms are not required to be provided, a number of trays can be provided with the dishwasher and used in the manner as described.

A further advantage of either embodiment is that the rotatable assemblies in accordance with the invention can be selectively positioned to provide the most effective cleaning action.

The provision of the rotational members herein described therefore clearly improves the dispensation and dispersion of the fluid within a dishwasher cabinet. This improvement in dispersion in turn provides an improvement in the cleaning of the utensils and the efficiency of operation of the dishwasher.