FR2674740A1 - DISHWASHER WASHING MACHINE WITH SELF-CLEANING RECIRCULATION FILTER. - Google Patents

Abstract

The invention relates to a dishwashing machine with a self-cleaning recirculation filter. The dish washing machine comprises a washing tub (1, 2) provided with a self-cleaning recirculation filter (5) having a frustoconical part (6), provided with a central opening (13) connecting the interior of the suction tank of a drain pump (8), as well as a cylindrical part (9) which extends from the opening, downwards. A reel (4) directs, towards the filter, a first and a second jets of liquid (16, 17) turned towards the central opening and respectively tangential with respect to the frustoconical part and to the cylindrical part. The central opening (13) is arranged at a level higher than the peripheral edge (15) of the frustoconical part (6) and at the maximum dynamic level (A) of the liquid, located upstream of the recirculation filter (5). Applications: Household appliances

Description

The present invention relates to a dishwashing machine having

  what is called a "recirculation" filter, suitable for cleaning

  automatically during operation of the machine.

  A dishwashing machine of this type is known, for example, from GB-B-2 204 482 and comprises a washing tub having a recirculation filter disposed on the flow path of the water sucked by a circulating pump, adapted to supply at least one rotating watering spool, disposed above the filter itself The filter comprises a portion 1 o having substantially the shape of an inverted truncated cone, with a central opening directly in communication the interior of the tank with the suction of a drain pump Another portion of the filter, substantially cylindrical, extends downwards from the central opening of the inverted frustoconical portion The two parts of the filter are concentric with respect to the axis of rotation of the reel, the latter directing towards the filter, a jet of water substantially tangential to the part

  cylindrical and able to clean it automatically.

  The reel also directs to the filter an additional water jet which is tangential to the inverted frusto-conical portion and therefore correspondingly inclines downwardly towards the central opening. particular, this other jet is able to push down, towards the central opening, and therefore to the hydraulic drain circuit, the dirt particles retained by the frustoconical part of the filter It follows that during operation of the machine, all dirt particles having a specific gravity greater than that of the functional liquid are automatically carried away by the entire recirculation filter. This solution is particularly advantageous, but does not eliminate the problem of dirt particles which, having a specific gravity near or below that of the functional liquid, remain in suspension in the liquid itself, which reduces the general performance of the machine. In fact, during the washing and / or rinsing phases, the recirculation filter is substantially immersed by the water collected at the bottom of the washing tub, in particular in the draining circuit, including the zone of the tank located upstream of the filter That is why, the greater part of the lighter dirt particles, carried by the recirculation filter and pushed towards the central opening of the inclined water jet (which is substantially immersed) , tend to float; as a result, rather than being trapped in the zone of relative calm, enclosed by the cylindrical part of the filter, the light dirt particles return

  suspension in the functional liquid.

  In addition, during a washing and / or rinsing phase, and / or at the end of the phase itself, at least one pause in the operation of the circulation pump may be provided; this normally occurs in the case where the dishwashing machine is carried out as described for example in EP-A-0 237 994, to supply, alternatively, two watering reels As is known, during this pause a rapid increase in the level of liquid collecting at the bottom of the washing tank is observed, with subsequent remixing of the dirt particles previously deposited inside the cylindrical portion of the filter. The remixed dirt particles therefore tend to return suspension

  in the liquid, which degrades the general benefits of the machine.

  The main object of the present invention is to provide a dishwashing machine provided with a self-cleaning recirculation filter, capable of filtering,

  optimally, almost all the dirt brought by the dishes.

  Another object of the present invention is to provide a dishwashing machine of the aforementioned type, in which possible interruptions of the

  not significantly impair the effectiveness of the autonet-

toyant.

  According to the invention, these and other objects are achieved by means of a dishwashing machine comprising a washing tub having a self-cleaning recirculation filter, arranged on the path of the fluid sucked by

  a circulation pump, adapted to feed at least one rotating reel

  the watering device arranged above the filter, the latter comprising a part

  substantially frustoconical, with a central opening connecting directly

  tank to the suction of a drain pump, as well as a cy-

  lindrique which is connected to said opening and extends downwards from the frustoconical portion, said reel being able to direct, towards the filter, at least a first and a second jets of liquid, turned towards said central opening and respectively substantially tangential to the surface of said frusto-conical portion and said cylindrical portion characterized by the fact that said central opening is disposed at an upper level by

  relative to the peripheral edge of the frustoconical part and to the dynamic level

  maximum of the liquid, located upstream of the recirculation filter.

  In the case where the liquid which collects at the bottom of said washing tank has

  dye said dynamic level and a higher static level, when the circulation pump is respectively in service and out of service, said

  central opening of the frustoconical portion of the recirculation filter is

  swam to a level above the static level.

  The features and advantages of the present invention will be better

  understood by reading the description below, made as an example only

  non-limiting with respect to the attached drawing The description refers to the

  attached figure, which shows schematically and partially the main components of the dishwashing machine according to the invention,

  in a preferred embodiment.

  The dishwashing machine mainly comprises a washing tub 1 (shown only partially), the bottom of which is defined by a sump 2 for collecting the washing and rinsing liquid. The collecting sump 2 communicates with the suction (not shown ) of a circulation pump 3, adapted to feed at least one rotary reel 4, for

  water, in known manner, washing dishes.

  The washing tub 1 also houses, beneath the reel 4, a fine-mesh recirculation filter 5 arranged on the path of the flow of

  water which, after having been sprayed on the dishes, is collected in the

  2, to be again sucked by the circulation pump 3 The filter comprises a substantially frustoconical portion 6, with a central opening 13 adapted to directly communicate the interior of the vessel 1 with the suction 7 of a drain pump 8 The filter 5 also comprises a substantially cylindrical portion 9, which is connected to the central opening 13 of the frustoconical part 6 and extends downwards,

  up to a wall 12 connected to the suction of the drain pump 8.

  The suction of the drain pump 8 can also communicate with the bottom of the sump 2, via a siphon-shaped element.

14, which allows its emptying.

  Preferably, as described for example in GB-B-2 204 482 supra, the cylindrical portion 9 of the recirculation filter releasably houses a coarse mesh pump protective filter, not shown for the sake of simplicity. , the recirculation filter S is substantially

  concentric with respect to the axis of rotation of the reel 4 and is made self-

  cleaning, thanks to two jets of water 16, 17 coming out of corresponding additional sprinklers 18, 19, of the reel itself In particular, the jets 16 and 17 are respectively substantially tangential with respect to the surface of the frustoconical part 6 and the part cylindrical 9, the recirculation filter. According to one aspect of the invention, the frustoconical portion 6 of the filter is arranged as shown in the figure, that is to say with the central opening 13

  higher relative to the peripheral edge, corresponding to the graduation 15.

  More specifically, the central aperture 13 of the filter is disposed at a level greater than the maximum dynamic level A of the water, situated upstream of the filter itself; however, the peripheral edge 15 may also be disposed at a level below said dynamic level A. It is recalled that the "dynamic level" means the level reached by the water collected at the bottom of the tank 1, 2, during a washing phase; as is known, this dynamic level is usually higher in the area upstream of the

recirculation filter.

  Therefore, during washing, the water jet 16 is inclined upwards and advantageously extends in the air, rather than being immersed in the water, at least as regards its final section. adjacent to the central opening 13 of the filter In addition, contrary to the known solutions, the recirculation filter 5, according to the invention, subdivides the bottom of the tank 1, 2 into three distinct zones, in which the water reaches Specific levels during the washing phases The dynamic level A above is reached, upstream of the filter 5, in the zone adjacent to the peripheral edge 15 of the frustoconical portion 6 inside the cylindrical portion 9, upstream of the filter of 1 o recirculation, a level B is reached, generally lower than level A, as verified also experimentally; in fact, the interior of the cylindrical portion 9 essentially receives only water cleaning jets 16 and 17 At the bottom of the collection sump 2, downstream of the filter 5 (that is to say in the area adjacent to the suction of the circulation pump 1 5 3), a level C is reached, lower than the levels A and B. As a result, the dirt particles retained by the frustoconical part 6 of the filter are pushed by the jet 16, towards the central opening 13, particularly effectively, despite the unfavorable inclination Indeed, in the worst operating conditions, the jet 16 is immersed in water

  only by its initial section, in which the pressure is higher.

  In addition, because they are practically immersed in the washing liquid, not only the heavier dirt particles, but also those having a specific weight lower than that of the liquid itself, are effectively pushed by the jet 16, towards the central opening 13 Therefore, virtually all the dirt particles retained by the frustoconical portion 6 of the filter fall, by gravity, through the opening 13, inside the cylindrical portion 9 , where they remain trapped, to be evacuated during a subsequent emptying phase It should be noted that, even if the nozzle 18 is partially immersed in the water, the rotation of the reel 4, which is normally rather slow, is not virtually

not altered.

  In a manner known per se, the dirt particles retained by the cylindrical part 9 are also carried away by the jet of water 17, almost all the filter 5 being, then, automatically cleaned during the

operation of the machine.

  In this connection, it should be noted that the jet of water 17 is also particularly effective, since the level B of the water contained inside the cylindrical portion 9 is relatively low, compared to the known solutions. offers another important advantage: since the degree of obstruction of the cylindrical portion 9 of the filter depends on the hydraulic pressure exerted by the liquid contained therein, and therefore on the level B, this

  degree of obstruction is correspondingly reduced.

  Ultimately, the dishwashing machine according to the invention is provided with a self-cleaning filter system 5, particularly simple and practical to filter effectively, and gradually, during operation, all the dirt brought by the This also allows, with equal benefits, to use a frustoconical part 6 with

  mesh larger, compared to known solutions.

  According to another aspect of the invention, in the case where the dishwashing machine is of the batch operation type of the circulation pump 3, during a washing and / or rinsing phase, the central opening 13 of the frustoconical portion 6 of the filter is provided at a level also greater than the "static" level of the water This static level, higher than the dynamic level A and designated by D in the figure, is the level reached by the water in the tank 1 , 2, when the circulation pump 3 is deactivated during a washing and / or rinsing phase. This is why, advantageously, it is avoided that the particles of dirt suspended in the liquid, contained inside the the cylindrical part 9, can overflow in the zone located upstream of the part

  frustoconical 6, from which they should be filtered again.

  Of course, the described dish washing machine can suffer many

  modifications falling within the scope of the invention.

Claims (2)

  A dishwashing machine comprising a wash tank equipped with a self-cleaning recirculation filter, arranged on the path of the fluid sucked by a circulation pump, adapted to supply at least one rotating watering spool disposed above the filter, the latter comprising a substantially frustoconical portion; provided with a central opening directly connecting the tank to the suction of a drain pump, and a cylindrical portion which is connected to said opening and extends downwards from the frustoconical portion, said reel being suitable directing, towards the filter, at least first and second jets of liquid, turned towards said central opening 1 and respectively substantially tangential to the surface of said frustoconical portion and of said cylindrical portion, characterized in that said central opening (13) is arranged at a higher level with respect to the peripheral edge (15) of the frusto-conical part (6) and at the maximum dynamic level (A) of the liquid, located in   upstream of the recirculation filter (5).   The dishwashing machine according to claim 1, wherein the liquid which collects at the bottom of said wash tank reaches said dynamic level and a higher static level, when the circulation pump is respectively in service and out of service, characterized by the fact that said central opening (13) of the frustoconical part (6) of the recirculation filter (5) is arranged at a level above said static level (D).