GB2191082A

GB2191082A - Dishwashing machine

Info

Publication number: GB2191082A
Application number: GB08713117A
Authority: GB
Inventors: Claudio Milocco; Gianni Santarossa; Sergio Tassotti
Original assignee: Industrie Zanussi SpA
Current assignee: Industrie Zanussi SpA
Priority date: 1986-06-04
Filing date: 1987-06-04
Publication date: 1987-12-09
Also published as: ES1002532U; IT8634035V0; FR2601869B3; GB2191082B; ES1002532Y; GB8713117D0; DE8707203U1; FR2601869A3; IT211138Z2

Abstract

In a dishwashing machine comprising a washing tub 3, rotary spray arm 6, circulating pump 5, discharge pump 9, and filter comprising an outer fine-mesh filter 7 and an inner coarse-mesh filter 8, at least part of water jet 11 is intercepted by pipe 12 in each revolution of the spray arm to form a jet 14 which is directed at deposited solid detergent at the intake 1 of the discharge pump in order to disturb it and enable it to be recirculated. In modifications, the pipe may intercept an intermittent jet of water, or may be of different configuration in order to intercept one of the conventional jets from the spray arm in the case where jet 11 is not provided. <IMAGE>

Description

SPECIFICATION Dishwashing machine with detergent recovery facility The present invention relates to a dishwashing machine provided with an arrangementfor recovering undissolved detergent deposited on the bottom ofthe water collectortank ofthe machine.

As is known, dishwashing machines generally comprise, on the bottom of the washing tub, a water collectortankfrom which a circulating pump and a discharge pump drawthe water to which detergent, normally in powder form, is added during the washing operation.

The collector tank houses a fine-mesh recirculating filter which is disposed in the flow path of the water which is drawn in by the circulating pump. Preferably, as described for example in Italian patent application No. 45740A/85 filed on 19th September 1985 by the present applicants, the recirculating filter substantially separates the intake cavity of the circulating pump from the intake cavity ofthe discharge pump which are in an intercommunicating condition byway of a valve arrangement which permits discharge ofthe washing solution from both the cavities.

The recirculating filter is shaped with an opening connecting the inside ofthewashing tub directly to the intake of the discharge pump. Disposed in that opening is a pump-protecting filter of large-mesh type which can be kept automatically cleaned by means of a continuous or intermittent coaxial jet of water as described in Italian utility model No. 198 766.

As is known, a certain amount ofdetergentwhich is not dissolved in the washing water tends to be deposited on the bottom of the collectortank ofthe dishwashing machine, where it remains unused.

It would be desirable, and this is the aim ofthe present invention, to provide a dishwashing machine which is capable of limiting the detergent wastage by recovering detergent deposited on the bottom ofthecollectortank.

According to the present invention, there is provided a dishwashing machine comprising a washing tub, a circu lating pum p, a fine-mesh fi Iter which is disposed in the flow path of waterwith detergent added thereto drawn in by the circulating pump,thefine-meshfilterbeing formed with an opening directly connecting the interior of said tub to the intake of a discharge pump, in which opening a wide-mesh filter is disposed, and spray means for directing an intermittent jet of water at the intake of the discharge pump, downstream ofthe wide-mesh filter, to remove the detergent deposited thereat.

The features and advantages ofthe invention will be clear from the following description with reference to the accompanying drawing showing a diagrammatic view in section of a preferred embodimentofdishwashing machine according to the present invention.

Referring to the drawing, the dishwashing machinecomprisesawashingtub3(onlypartof which is shown) provided on its bottom with a tank4 for collecting thewashing and rinsing water.

Disposed in the tank 4 is a circulating pump 5 operable to supply at least one rotary arm 6 for spraying the dishes to be washed (not shown), in known manner. The washing tub 3 houses a filter 7 of fine mesh type which is disposed in the flow path of the water which, after having been sprayed on to the dishes, is collected in the tank4 and is drawn in again by the circulating pump 5. In known manner, the filter 7 is formed with a frustoconical opening 2 directly connecting the interior ofthe tub 3 to the intake 1 of a discharge pump 9. Removably positioned in the frustoconical opening 2 is a pump-protecting filter 8 of large mesh type, which is of a corresponding shape and which is disposed substantially in the flow path of the water that is drawnfromthetank4bythedischargepump9.

As described for example in Italian untility model No. 198766, provided on the lower side of the rotary arm 6 is at least one additional opening 10 which is operable to produce a corresponding continuous jet of water 11 which is substantially aligned with the wide-mesh filter 8 and which is capable of intermittently providing for automatic cleaning by causing the notverysolid lumps of dirt collected therein to become mushy.

At least one pipe 12 which is preferably fixed with respectto the filter 8 and which is coaxial therewith extends with one end disposed atthe location ofthe intake 1 of the discharge pump 9, downstream ofthe filter 8, and with the opposite end preferably disposedata level higherthanthehighestdynamic level of the water in the tub indicated at 13 and shown by dash-dotted lines. As is known, the term dynamic level means the level of the water which is collected onthe bottom ofthewashingtub3when the circulating pump 5 is in operation.

Preferably, the upper end of the pipe 1 2 is of a funnel-shaped configuration in ordertemporarilyto interceptatleastpartofthewater jet 11, in each revolution of the arm 6. The water jet 11 is thus transformed bythe pipe 12 into an impulse jet 14 which is directed towards the intake 1 at a frequency which is dependent on the speed of rotation (which is relatively low) of the arm 6. Therefore the intake 1 ofthe discharge pump 9 which is a relatively calm area in which acertainamountofundissolvedand thus unused detergent normally tends to be deposited is periodically put into a condition of slight agitation by the effect ofthe jet of water 14 produced bythe pipe 12.That agitation which inthe embodiment described herein, at the location of the intake 1, assumes lines offlowwhich are substantiallytoroidal and concentric with respect to the pipe 12 causes removal of the detergent which is deposited thereat, and which can thus be returned to circulation by the pump 5, passing through the filter 2 in theform of solution. It should be noted thatthe presence of the pipe 12 does not materially alterthe self-cleaning effect ofthe filter 8 and at the same time makes it possible to minimise detergent wastage, as is the aim of the present invention.

Anotherimportantaspectofthe machine lies in the fact that intermittent agitation at the intake 1 of the discharge pump, which occurs at a relatively low frequency and which involves a limited region of the tank4, does not maintain the particles of dirt accumulated in that region in a condition of suspension but permits them to be redeposited on the bottom ofthe tank between one pass and another ofthe jet 11 overthe pipe 12. That prevents the particles of dirtfrom being drawn in by the pump 5 and causing undesirable blockage of the filter 7.

It will be appreciated that the dishwashing machine described hereinbefore may be the subject of any modifications within the scope of the invention. For example the pipe 12 may be of a different configuration in order to intercept one of the conventional jets from the rotary arm 6, in case the additional jet 11 is not provided.

Alternativelythe pipe 12 may intercept a fixed intermittent jet of waterwhich is provided within the washing tub 3 and/or it may be arranged in a different mannerto cause an impulse agitation effect in the lower region of the tank4 where undissolved detergenttendsto be deposited.

Claims

1. Adishwashing machine comprising a washing tub, a circulating pump, a fine-mesh filterwhich is disposed in the flow path of water with detergent added thereto drawn in by the circulating pump, the fine-mesh filter being formed with an opening directly connecting the interior of said tub to the intake of a discharge pump, in which opening a wide-mesh filter is disposed, and spray means for directing an intermittentjetofwateratthe intake of the discharge pump, downstream of the wide-mesh filter, to remove the detergent deposited thereat.

2. A dishwashing machine according to claim 1 wherein the circulating pump is arranged to feed at least one rotary arm arrangement for producing at least one continuous jet of water, the spray means comprising hydraulic connecting means operable to intercept intermittently and at least partially said continuous jet of water and to carry it to the intake of the discharge pump.

3. A dishwashing machine according to claim 2 wherein said continuous jet of water is periodically dirnctedagainstthewide-meshfilterand is substantially coaxial therewith,the hydraulic connecting means comprising at least one pipe of which one end is capable of intercepting at least partially said continuousjet ofwater and ofwhich the other end is disposed in association with the intake of the discharge pump, the pipe being fixed with respect to the wide-mesh filter and substantially coaxial therewith.

4. Adishwashing machine according to claim 3 wherein the first end of said pipe is of a funnel-shaped configuration.

5. Adishwashing machine according to claim 3 or4wherein the first end of said pipe is disposed at a level higherthan the dynamic level of the water in the tub when the circulating pump is operating.

6. A dishwashing machine constructed and arranged to operate substantially as hereinbefore described with reference to the accompanying drawing.