GB2233220A - Spray arm mounting in dishwashing machine - Google Patents

Abstract

A rotary spray arm assembly 1 of a dishwashing machine is mounted on a pin 4 projecting from a tube 5 having an annular internal cavity 6 through which wash liquid is supplied to the arm and a flange 8 having opening 11 coincident with cavity 6 and an upwardly-extending peripheral portion 12 is interposed between the base of the arm assembly and the tube, said portion being designed to deflect wash liquid passing through gap 16 in use upwardly against the bottom of the spray arm assembly. <IMAGE>

Description

DISHWASHING MACHINE ROTATING ARM ASSEMBLY The invention relates to dishwashing machines and in particular to a rotating arm assembly thereof which is of such a configuration as to permit effective recovery of the washing solution which is dispersed during the phase of washing the crockery.

As is known, present dishwashing machines are provided with two rotating arm assemblies disposed one above the other and connected by way of a recirculating conduit to an electric pump for producing circulation of the washing solution and spraying thereof over the crockery during each crockery washing programme. Each of the arm assemblies has a hollow interior and is provided with a plurality of nozzles for spraying the washing solution over the crockery.

It is also provided with a central cavity which can be fitted on to a corresponding pin member accommodated in a rigid tubular portion connected to the recirculating conduit of the machine and that arm assembly is loosely mechanically coupled to the tubular portion to permit rotary movement of the arm assembly about the respective pin member, whereby a gap is defined in the coupling zone, through which the washing solution which can pass through the tubular portion and the arm assembly is partially dispersed to the exterior and collected in the subjacent drain region of the washing vessel of the machine in which the above described circulating pump is disposed.Consequently, dishwashing machines provided with arm assemblies of that type require the provision of circulating pumps which are designed to produce flow rates and pressure heads which are greater than those actually required in order to be able to produce spray pressures which are sufficient to give satisfactory crockery washing results and also to recirculate the quantity of washing solution which is dispersed through the gap at each arm assembly and collected in the drain region of the machine. It would therefore be desirable, and this is the aim of the present invention, to provide a washing solution spray arm assembly for dishwashing machines such as to improve the recovery of the washing solution which is dispersed at the location of the mechanical arm assemblytubular portion connection, using same to improve the crockery cleaning action.

Accordingly to the present invention, there is provided a dishwashing machine comprising a washing vessel, at least one pump for circulating crockery washing solution which is connected by way of a recirculating conduit to a vertically extending rigid tubular portion, and an internally hollow arm assembly provided with nozzles for spraying the washing solution onto the crockery and also being mechanically couplable to the upper end of said tubular portion in such a way that it can be driven in rotation during the performance of any washing programme of the machine, the arm assembly comprising deflection means disposed in the region of the coupling between the arm assembly and the upper end of said tubular portion and capable of determining the flow of the washing solutio towards the arm assembly and diverting towards the arm assembly the solution which is dispersed externally through said coupling zone.

The invention will be further described by way of non-limitative example with reference to the accompanying drawing in which the sole figure is a sectional front view of the arm assembly of an embodiment of the invention.

As can be seen from the accompanying drawing which illustrates an arm assembly 1 for spraying the washing solution over the crockery in a dishwashing machine, it will be noted that the arm assembly, in the usual manner, is internally hollow and is provided with a plurality of spray nozzles 2 which are disposed on the upper part thereof, and a central cavity 3 which can be fitted onto a corresponding pin member 4 projecting upwardly from a rigid tubular portion 5 disposed within the washing vessel (not shown) and connected by way of a washing solution recirculating conduit to a conventional circulating pump (both the conduit and the pump are not shown), the pump being accommodated in the drain region for collecting the washing solution (not shown) provided in the lower part of the washing vessel of the machine.The rigid tubular portion 5 is provided with an annular internal cavity 6 defined between the internal wall of the tubular portion 5 and the external wall of a vertical tube 7 disposed concentrically in the interior of the tubular portion; the crockery washing solution circulates by way of the cavity during the performance of the various washing programmes of the machine.To permit mechanical coupling of the spray arm assembly 1 to the tubular portion 5, which coupling is of a loose nature to permit rotary actuation of the arm assembly, fitted beforehand to the free upper end of the tubular portion 5 is a circular flange 8 of reduced thickness and provided with vertical mutually concentric walls 9 and 10 which can be respectively fitted against the corresponding external and internal walls of the vertical tube 7 and the tubular portion 5, while also being provided with a circular through opening 11 which is coincident with the internal cavity 6 of the tubular portion 5 and capable of permitting circulation of the washing solution towards the spray arm assembly 1.

The circular flange 8 is also provided with a circular peripheral edge 12 which is inclined and extended upwardly so as to be directed towards the underneath surface of the arm assembly 1. In turn the arm assembly 1 is provided with a widened circular portion 13 which can be fitted against the circular flange 8 and which is shaped in such a way as to provide a flat annular surface 14 capable of coming to bear against the corresponding flat upper surface 15 of the flange 8 in the position in which the widened portion 13 and the flange 8 are coupled together.

To permit rotary movement of the arm assembly 1, it is fixed on the pin member 3 with a slight amount of axial play in such a way that it can be displaced vertically from a rest position in which the flat surfaces 14 and 15 of the widened portion 13 of the arm assembly 1 and the flange 8 are in abutment with each other in the inoperative condition of the arm assembly, to a working position in which the above mentioned flat surfaces are moved away from each other in the vertical direction by the thrust force exerted by the washing solution as it passes through the tubular portion 5 and the arm assembly 1, during the performance of any washing programme of the machine, thus defining a gap 16 for the washing solution to pass towards the outside of the tubular portion 5.In that way, by virtue of the presence of the circular inclined edge 12, the washing solution which is dispersed through the gap 16 is diverted upwardly against the bottom surface of the spray arm assembly 1, applying thereto a further thrust force which is added to the dynamic thrust force produced by the flow of the washing solution through the arm assembly and which increase the torque for rotation of the arm assembly.

The arm assembly of the above discussed configuration makes it possible effectively to recover the washing solution which issues through the gap 16 which, by virtue of the thrust force applied against the arm assembly 1 during its entire rotation about its vertical axis, makes it possible to use circulating pumps of sizes such as to provide the flow rates and pressure heads which are actually required by the washing programmes, with the consequence of reduced production costs for same, while making it possible to achieve equal levels of washing performance.

Claims (3)

1. A dishwashing machine comprising a washing vessel, at least one pump for circulating crockery washing solution which is connected by way of a recirculating conduit to a vertically extending rigid tubular portion, and an internally hollow arm assembly provided with nozzles for spraying the washing solution onto the crockery and also being mechanically couplable to the upper end of said tubular portion in such a way that it can be driven in rotation during the performance of any washing programme of the machine, the arm assembly comprising deflection means disposed in the region of the coupling between the arm assembly and the upper end of said tubular portion and capable of determining the flow of the washing solutio towards the arm assembly and diverting towards the arm assembly the solution which is dispersed externally through said coupling zone.

2. An arm assembly according to claim 1 in which said deflection means comprise a circular flange which can be fitted onto the upper end of said tubular portion and which is provided with a through opening which is coincident with the internal cavity of said tubular portion and also provided with a circular peripheral edge which is inclined and directed towards said arm assembly.

3. A dishwashing machine constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.