Method of rinsing in a dishwasher and device for carrying out the method

Abstract: The invention relates to a method and to a device for carrying out the method for rinsing in a dish washer with a rinse water (12) circuit, in which the rinse water (12) is evacuated from the sump of the wash chamber (29) by means of a circulating pump (30) and, passing through a filter (10), is supplied to the spray devices (24,25) in the wash chamber (29), the filter (10) being cleaned in counterflow to the rinse water (12) by means of introduced cleaning water (22). During the entire rinsing procedure the filter (10) is cleaned in counterflow, the dirt particles in the filter (10) being kept in suspension. The cleaning water (22) is supplied to the rinse water circuit and preferably removed therefrom.

Description: The invention relates to a method for rinsing in a dishwasher with a rinse water circuit in which the rinsing water is evacuated by a circulating pump from the sump of the wash chamber and, passing through a cylindrical filter, is supplied to the spray devices in the wash chamber, the filter being cleaned in counterflow to the rinse water by means of supplied cleaning water during the overall rinsing procedure, and to a device for carrying out the method. A method of the above named type is known from FR-A-2081286 and US-A-3989054. In these documents the rinse water passing through the fixed filter and the cleaning water are supplied in common to the rinse water circuit upstream the circulating pump. DE-OS 14 28 358 discloses a method in which a partial flow of the fresh water is used as cleaning water. In order that the filter is acted upon by the cleaning water over its entire exterior, it is necessary to have a spray device surrounding the filter, which is provided with a plurality of nozzles directed at the filter. In this respect it is also possible to use a spray device with only one single nozzle, which is oriented obliquely at the exterior of the filter and in this way causes the filter to move rotarily. The cleaning phase however is separated from the rinsing procedures, as in that case the outflow from the filter is open. The cleaning procedure in another dishwasher known from DE 37 23 721 A1 operates in a similar manner. Here also, in order to clean the filter, the counterflow principle is used for the cleaning water. The cleaning procedure is effected in special cleaning stages provided in the working cycle. In this case the rotary movement of the filter may be achieved in various ways. Fresh water is likewise used as cleaning water. It is the purpose of the invention to provide a method and a device for carrying out the method of the type already mentioned, in which and by means of which cleaning of the filter may be carried out during the entire spraying procedure in a more effective way. This purpose is fulfilled according to claim 1. DE-B-1269776 discloses a device for cleaning a filter in a dishwasher in which the filter screen, cleaned in couterflow to the rinse water, is fixed with respect to cleaning nozzles. The filter according to such document is placed upstream the circulating pump. The device for carrying out the method is made according to claim 6. In the method according to the invention the filter is acted upon by cleaning water during the overall rinsing procedure. This leads to a situation in which the dirt particles cannot come to rest in the filter and are kept permanently in suspension. This permanent cleaning operation is enabled by the fact that the cleaning water is supplied to the rinse water circuit. In order to avoid overcharging the latter, the method is further developed in such a way that a partial flow of the rinse water is used as cleaning water, being removed from the rinse water circuit in front of the filter. Propulsion of the filter in the method according to the invention may be undertaken in various ways, similarly to prior art, one preferred development being characterised in that, when the lower spray device is in the form of a reaction wheel, the filter is non-rotarily connected to the spray device and is rotated therewith. In the device for carrying out the method, the supply of cleaning water is such that the input for the cleaning water is in the form of a wide-slot nozzle, which acts upon the filter over its entire vertical dimension. A constructively simple solution for propulsion and for rotary mounting of the filter is characterised in that the closed end face of the filter is non-rotarily connected by means of a shaft to the rotatably mounted lower spray device, and in that this shaft is rotarily mounted at least in bearing members of the filter housing, which leave free a passage for the rinse water supplied to the rinse water circuit. The rotary mounting can be further improved in that the filter, with its input for the rinse water to be filtered, is freely rotatably mounted in a fluid-tight manner in the filter housing. The invention will be explained in more detail with reference to an embodiment given by way of example and illustrated in the drawing. Shown are: Figure 1: a perspective, partly sectional view of a filter device suitable of the method according to the invention, with cleaning device, and Figure 2: a basic circuit diagram for illustrating the method. In Figure 1, a hollow cylindrical filter 10 is entirely enclosed on the end face 16 which is at the top in the drawing. The opposite, lower end face 17 of the filter 10 has an input 19 for the rinse water 12 to be filtered, which is supplied from the circulating pump UP of the rinse water circuit. This rinse water 12 must pass through the filter 10, the dirt particles being retained in the filter 10. The filter 10 is rotatably mounted in a filter housing 11. The filter housing 11 surrounds the filter 10 and forms an annular chamber relative thereto. In addition, the filter housing 11 is provided with an input 13 for cleaning water 22, in the form of a wide-slot nozzle, so that the cleaning water 22 is supplied over the entire height of the filter 10. In order that the entire outer side is acted upon by cleaning water, the filter 10 must be rotated. In the embodiment there is rigidly connected to the upper end face 16 of the filter 10 a shaft 14, which is connected in a way not shown, e.g. non-rotarily, to the lower spray device rotatably mounted in the wash chamber, and which is propelled according to the principle of the reaction or Barker's wheel. The upper end face of the filter housing 11 is in the form of a passage 15, from which the rinse water 12 passing through the filter 10, together with the cleaning water 22 supplied through input 13, is passed to the rinse water circuit. In this region the filter housing 11 has simply bearing members 18 for rotarily mounting the shaft 14, so that a sufficiently large cross-section remains for the passage 15. As is further to be seen from Figure 1, after the rinsing procedure, and with valve 21 open, the rinse water circuit inclusive of the filter device is emptied with a lye pump LP, 28, the dirt particles retained in the filter 10 flowing out through the input 19. Due to the constant supply of cleaning water 22 in counterflow to the rinse water 12, the dirt particles cannot settle securely on the inner wall of the filter 10; they are kept in constant suspension in the filter 10, so that in this way automatic cleaning of the filter 10 is achieved, even if said filter has an extremely fine mesh. In order to avoid additional load on the rinse water circuit by the cleaning water 22, a portion of the rinse water itself may be used as cleaning water 22. Therefore a partial flow is removed from the rinse water circuit in front of the filter 10, as Figure 2 shows. By means of this development, control of the rinsing procedures may remain undisturbed, as the amount of rinse water introduced into the rinsing procedure by the permanent cleaning of the filter 10 does not change. As shown diagrammatically in the illustration according to Figure 2, an upper spray device 25 and a lower spray device 24 are rotarily mounted in the wash chamber 29 provided with the sump 23. It is propelled in a known way by the emerging rinse water. During the rinsing procedure, the circulating pump 30, identified as UP, evacuates the collected rinse water in the sump 23 through the fine filter 31 and the coarse filter 32 and fine filter 33 located parallel therewith and mounted in series, and supplies it to the rinse water pipe 20 of the rinse water circuit. At the rinse water pipe 20 the rinse water 12 to be filtered, the partial flow of the rinse water used as cleaning water 22, and the rinse water 26 for the upper spray device 25 are diverted. Both partial flows 12 and 22 are unified at the outlet 15 of the filter device and are supplied to the lower spray device 24. Thus the rinse water circuit is closed. The fine filters 31 and 33 and the coarse filter 32 are manually removed and cleaned. In this arrangement, the filter 10 is preferably in the form of a fine-meshed filter. After the rinsing procedure, the valve 21 is opened and the rinse water circuit is emptied through the non-return valve 27 and the lye pump LP which is provided with reference numeral 28, the dirt particles passing through the input 19 out of the filter 10. If the rotary mounting of the filter 10 is to be improved, then the input 19 of the filter 10 may be additionally mounted, yet in a fluid-tight manner in the underside of the filter housing 11.

Claims: Method for rinsing in a dishwasher with a rinse water circuit in which the rinsing water is evacuated by a circulating pump from the sump of the wash chamber and, passing through a cylindrical filter, is supplied to the spray devices in the wash chamber, during the overall rinsing procedure the filter being cleaned in counterflow to the rinse water by means of supplied cleaning water, characterised in that the filter (10) is rotated, and in that the rinse water (12) passing through the filter (10) and the cleaning water (22) are supplied in common to the rinse water circuit downstrean the circulating pump (30). Method according to Claim 1, characterised in that the filter (10) is rotated by means of a drive device. Method according to Claim 1, characterised in that the filter (10) is rotated by a partial cleaning flow (22) impinging tangentially on the outer side of the filter (10). Method according to Claim 1, characterised in that when the lower spray device (24) is in the form of a reaction wheel, the filter (10) is non-rotarily connected to the spray device (24), and is rotated therewith. Method according to one of Claims 1 - 4, characterised in that there is used as cleaning water (22) a partial flow of the rinse water, which is removed from the rinse water circuit before the filter (10). A device for cleaning a filter in a dishwasher in which rinsing water is evacuated by a circulating pump (30) from the sump of the wash chamber and, passing through a hollow cylindrical filter (10), is supplied to spray devices in the wash chamber, the filter being cleaned in counterflow to the rinse water by means of supplied cleaning water, the device comprising a filter housing (11), the hollow cylindrical filter (10), and an annular chamber surrounding the filter, the annular chamber being formed between the filter housing and the filter, characterised in that the hollow cylindrical filter (10) is rotarily mounted in the filter housing (11), the filter (10) being closed at one end face (16) and provided on the opposite end face with an input (19) for the rinse water (12) to be filtered, the filter housing (11) having an input (13) for the cleaning water (22), and in that the filter housing (11), facing away from the input (19) for the rinse water (12), is incorporated as an output for the cleaning water (22) unified with the rinse water (12) in the rinse water circuit downstream the circulating pump (30). Device according to Claim 6, characterised in that the input (13) for the cleaning water (22) is in the form of a wide-slot nozzle, which acts upon the filter (10) over its entire vertical dimension. Device according to Claim 6 or 7, characterised in that the closed end face (16) of the filter (10) is non-rotarily connected by means of a shaft (14) to the rotarily mounted lower spray device (24), and in that the shaft (14) is rotarily mounted at least in bearing members (18) of the filter housing (11), leaving free a passage (15) for the rinse water supplied to the rinse water circuit. Device according to one of Claims 6 - 8, characterised in that the filter (10), with its input (19) for the rinse water (12) to be filtered, is freely rotatably mounted in a liquid-tight manner in the filter housing (11). Device according to one of Claims 6 - 9, characterised in that the filter (10) is in the form of a fine-meshed ultrafine filter. Device according to one of Claims 6 - 10, characterised in that the filter housing (11) is heart-shaped at least in the upper cross-sectional area associated with the outlet.

Inventors: KLOSS GERD, MAURER CHRISTA, RAUBER LUDWIN, RHEIA REINOLD, KLOSS, GERD, MAURER, CHRISTA, RAUBER, LUDWIN, RHEIA, REINOLD, Kloss, Gerd, c/o Whirlpool Italia S.p.A., Maurer, Christa, c/o Whirlpool Italia S.p.A., Rauber, Ludwin, c/o Whirlpool Italia S.p.A., Rheia, Reinold, c/o Whirlpool Italia S.p.A.
Applicants: BAUKNECHT HAUSGERAETE, WHIRLPOOL EUROP, BAUKNECHT HAUSGERAETE GMBH, WHIRLPOOL EUROPE B.V.
Application year: 1995
Main classification: A47L15
IPC codes: A47L15