METHOD AND DEVICE IN A CLEANING MACHINE

Abstract: A method and a device for separating granules from a return flow of a cleaning fluid being a mixture of a liquid and granules having a higher density than the liquid, the return flow appearing through a treatment chamber (10) and a tank (15) below the treatment chamber (10) in a washing machine having at least one granule collector (19). The granule collector (19) is arranged as a self-contained unit and to enter a collect mode to receive a substantial amount of the return flow and to retain granules therein. The granule collector (19) is also arranged to enter a release mode to release retained granules and to allow the return flow to pass by without retaining granules.

Description: 1 METHOD AND DEVICE IN A CLEANING MACHINE TECHNICAL FIELD This invention relates to a method and a device in a cleaning machine to clean goods using as a cleaning fluid either a liquid mixed with granules or the liquid itself only. The granules have a density higher than that of the liquid. The liquid can be any liquid with cleaning properties but usually consist of water with various additives to enhance and improve the cleaning proper- ties. Goods in this context refer to the soiled objects that are to be cleaned. Goods could be any objects that require to be cleaned but usually refers to pots, pans and other kitchen and cooking utensils that are difficult to clean with traditional cleaning machines. BACKGROUND ART The cleaning fluid is pumped from a tank and discharged under pressure against the goods disposed in a treatment chamber. If the goods are heavily soiled the cleaning fluid consists of a liquid mixed with granules. At the end of the cleaning operation it is necessary to flush the goods with a liquid without the granules in order to remove that granules from the goods. This calls for a separation method that can be activated in order to separate the granules from the cleaning fluid and de-activated when it is desirable to mix granules into the cleaning fluid. If the goods are less soiled, the separa- tion method is never de-activated which enables the cleaning of the goods using a cleaning fluid without granules. After having been discharged against the goods the cleaning fluid is allowed to flow back as a return flow into the tank from which it is re-circulated for as long as it is desired that the cleaning cycle should last. Cleaning machines functioning according to the principle described above exist, using various methods to separate the granules from the cleaning fluid. These methods include using sieves or letting the heavy granules sediment in a partition of the tank. 2 While these machines operate satisfactorily, they have one weakness in common insofar that they are difficult to clean at the end of a working shift. This is due to the fact that the granules remain in the tank in or around the separation device which makes access to cleaning the tank bottom difficult. In view of the increasing demands from users for improved hygienic properties of cleaning machines, some manufacturers have addressed this problem by supplying additional granule collectors in the treatment chamber instead of goods to enable users to remove the granules from the machine. Most machines, however, due to their design, are difficult to clean internally. DISCLOSURE OF INVENTION It is an object of the present invention to overcome the drawbacks of prior art machines and to provide a method and a device for the separation of granules from the cleaning fluid. A further object of the invention is to provide through the design of said apparatus, a simple method for removing the collected granules from the machine. A still further object is to provide a simple machine that can be produced at a low cost. This invention addresses these problems by offering a simple method of combining the separation and the collection of the granules, leaving the tank interior accessible for cleaning and also facilitating the cleaning of the granules themselves as well as the measuring of the amount of granules in the machine to see if more granules are needed. At the same time it simplifies the design of the machine which in turn lowers the manufacturing costs. A collector for granules is provided in the return flow of cleaning fluid including granules through the treatment chamber and the tank to a tank outlet to the pump. The collector may be detachable from the cleaning machine. In a first mode of operation, here referred to as a collect mode, the collector will allow liquid to pass through and by the collector while retaining the granules. In a second mode of operation, here referred to as a release mode, the collector will release previously collected granules into the cleaning fluid and also let the return flow of cleaning fluid to pass by or through the collector without retaining the granules from the liquid. 3 Further features and advantages of the invention are shown in the description below and in the dependent claims. BRIEF DESCRIPTION OF DRAWINGS The invention will now be described in more detail with reference to the accompanying drawings, in which FIG 1 is a perspective view of a cleaning machine with a cut of section according to one embodiment of the invention with collectors in the collect mode, FIG 2 is a corresponding view with collectors in the release mode, FIG 3 is a schematic side view of a first alternative embodiment of collectors according to the invention in the release mode, FIG 4 is schematic view of the collectors of FIG 3 in the collect mode, FIG 5 is a schematic side view of a second alternative embodiment of collectors according to the invention in the release mode, and FIG 6 is schematic view of the collectors of FIG 5 in the collect mode. DETAILED DESCRIPTION As shown in FIG 1 a cleaning machine according to one embodiment of the invention comprises of a treatment chamber 10 in which goods 11 are placed in a washing rack 12. Nozzles 13 in a discharge pipe 14 are provided through which the cleaning fluid including granules is discharged under pres- sure against the goods 11. After impacting the goods 11 the granules, together with liquid, form a return flow. Below the treatment chamber 10 there is a tank 15 receiving the return flow from the treatment chamber 10. From an outlet 21 of the tank 15 the cleaning fluid is taken by a pumping device 16 which discharges the cleaning fluid into a conduit 17 leading to a discharge pipe 18. 4 One or more granule collectors 19 are provided in the return flow, either in the tank 15 as shown in FIG 1 or in the treatment chamber 10. The granule collectors 19 are formed as self-contained units, that is the collectors are separate from the walls of the treatment chamber 10 and the tank 15. FIG 1 shows an embodiment having two granule collectors 19 mounted side by side in the tank 15. The granule collectors shown comprise side walls 22, a bottom side wall 26, a rear gable end wall 24 and a front gable end wall 27, said walls forming together a box or container. Some or all of the walls may be perforated. In the shown embodiment the side walls 22 have been perforated. In other embodiments a net or similar device is used to collect the granules in the granule collectors while allowing the cleaning liquid to pass through openings therein. However, it possible also to use granule collectors 19 that have no openings. In such an embodiment the cleaning liquid will overflow the rim of the granule collectors. It should be noted that even for collectors with perforations or other openings to let the cleaning liquid through, some of the return flow may overflow the rim of the collector. Through the means of various types of actuators, not shown, the collectors 19 can be made to occupy different positions in relation to said flow, so as to change from the collect mode to the release mode and back as desired. The granule collectors may be hinged on at least one shaft 23, so as to rotate from one position to the other by means of the actuators. In other embodiments the granule collectors change the mode of operation through a sliding movement or a combination of a rotating and a sliding movement. The granule collectors 19 may be fitted to the actuating device in such a way that they can be lifted out of the machine together with the collected granules, thus leaving the interior of the machine free from granules and easily accessible for cleaning purposes and also to facilitate the cleaning of the granules. In this way also the measuring of the amount of granules will be facilitated and more granules can easily be added if needed. In the collect mode, as shown in FIG 1 , the granule collectors 19 capture all or a portion of the return flow, and granules will be retained therein 5 while the cleaning fluid is allowed to pass through or by the collectors. In this way the granules will be separated from the cleaning fluid. I should be noted that the granule collectors 19 will not receive the complete return flow. Some part thereof, this part also including granules, will pass by the granule collectors and will be re-circulated to the treatment chamber 10. However, only a few iterations will be required until all granules are collected. The return flow normally is very vigorous and granules already collected in the granule collectors 19 can be forced out thereof. It may be ap- propriate to include a flow director or a coarse screen or a similar device to protect the granule collectors from a direct impact of the return flow. An example of such a device is shown in FIG 3 and FIG 4. FIG 2 shows the collectors 19 in the release mode. After displacement into such a second position, the collectors 19 will release the granules into the cleaning fluid and will not collect any granules from the return flow of the cleaning fluid. FIG 3 shows a first alternative embodiment of granule collectors 19 in the release mode. In this embodiment two opposing side walls 22 of the granule collectors are arranged pivotable on a shaft 23. The side walls 22 are formed with through holes 25. The size of the through holes is smaller than the size of the granules. The granule collector also comprises a rear gable end wall 24 and an opposing front gable end wall (not shown). No granules are captured or retained in this position. To protect the granule collectors 19 from a direct impact of the return flow and also to direct the granules in the return flow towards the granule collectors a flow directing means 28 is arranged above the tank 15. In the flow directing means 28 there is provided a plurality of granule openings 29. The size and location of the granule openings 29 will allow granules to pass through the flow directing means 28 and to enter into the granule collectors 19. Thus, the granule collectors 19 will be filled with granules faster and granules will not be washed away. 6 In FIG 4 the side walls 22 have been pivoted in opposite directions to form a V, and the granule collectors are in the collect mode. The side walls 22 together with the rear gable end 24 and a corresponding front gable end wail (not shown) form a container that will receive fraction by fraction of the granules and retain the granules therein. Preferably, the granule collectors 19 are connected to actuators for rotating the side walls 22 in such a way that the granule collector 19 can be removed from the machine with the granules collected therein. FIG 5 shows a second alternative embodiment of granule collectors 19 in the release mode. In this embodiment a box like granule collector 19 arranged in the treatment chamber 10 comprises side walls 22, rear and front gable end walls 24, 27 and a pivotable bottom side wall 26. The bottom side wall 26 is pivoted to an open position allowing fluid and granules to pass through the granule collector. In FIG 6 the bottom side wall 26 of the granule collectors in FIG 5 has been pivoted into a closed position and the granule collector is in the collect mode. Preferably, the granule collectors 19 are connected to actuators for rotating the bottom side wall 26 in such a way that the granule collectors 19 can be removed from the machine with the granules collected therein. It should be noted that it is not necessary to direct the total of the flow into the collectors. Although this speeds up the separation process, this invention gives a satisfactory result even if only a fraction of the return flow actually passes through the collectors. The reason for this is that the main pumping device circulates the total tank volume so many times during a normal separation period that practically all granules will be collected even if only a fraction of the return flow passes by the collectors.

Claims: 7 CLAIMS 1. Method for separating granules from a return flow of a cleaning fluid being a mixture of a liquid and granules having a higher density than the liquid, the return flow appearing through a treatment chamber (10) and a tank (15) below the treatment chamber (10) in a washing machine having at least one granule collector (19), c h a ra c t e r i s e d by arranging said granule collector (19) as a self-contained unit, by controlling said granule collector (19) into a collect mode to receive a substantial amount of the return flow and to retain granules therein, while allowing a minor amount of the return flow to pass by, and by controlling said granule collector (19) into a release mode to release retained granules and to allow the return flow to pass by without retaining granules. 2. Method according to claim 1 , wherein cleaning fluid is directed through perforated walls of said granule collector. 3. Method according to claim 1 , wherein said granule collector (19) is rotated between a first position in its collect mode and a second position in its release mode. 4. Method according to claim 1 , wherein side walls (22) of said granule collector (19) are rotated between a first position allowing the return flow to pass by between said side walls, said first position constituting the release mode of said granule collector (19), and a second position in which the side walls (22) together with gable ends (24, 27) form a container, said second position constituting the collect mode. 5. Method according to claim 1 , wherein the granule collector (19) is box shaped comprising side walls (22) and a bottom side wall (26), said bottom side wall (26) being rotated between a first position allowing the return flow to pass through, said first position constituting the release mode of said granule 8 collector (19), and a second position in which the bottom side wall (26) closes the granule collector (19) to retain the granules therein, said second position constituting the collect mode. 6. Method according to claim 1 , wherein said granule collector (19) is mounted detachable in the washing machine to be detached therefrom while holding the granules, so as to allow the cleaning of the interior of the washing machine. 7. A device for separating granules from a return flow of a cleaning fluid being a mixture of a liquid and granules having a higher density than the liquid, the return flow appearing through a treatment chamber (10) and a tank (15) below the treatment chamber (10) in a washing machine having at least one granule collector (19), c h a r a c t e r i s e d in that said granule collector (19) is arranged as a self-contained unit, that said granule collector (19) is arranged to enter a collect mode to receive a substantial amount of the return flow and to retain granules therein, while allowing a minor amount of the return flow to pass by, and that said granule collector (19) is arranged to enter a release mode to re- lease retained granules and to allow the return flow to pass by without retaining granules. 8. A device according to claim 7, wherein the granule collector (19) comprises perforated side walls (22), so as to allow the cleaning fluid to pass through the granule collector (19) in either mode. 9. A device according to claim 7, wherein the granule collector (19) is ro- tatably mounted. 10. A device according to claim 7, wherein the granule collector (19) is box shaped with a bottom side, side walls and an open top side. 9 11. A device according to claim 7, wherein side walls (22) of the granule collector (19) are mounted to be rotated between a first position forming an open passage for the return flow, and a second position forming together with opposing gable ends a container for retaining granules appearing in the return flow. 12. A device according to claim 7, wherein a bottom side wall (26) of the granule collector (19) is mounted to be rotated between a first position forming an open passage for the return flow, and a second position forming to- gether with side walls (22) and opposing gable ends a container for retaining granules appearing in the return flow. 13. A device according to claim 7, wherein the granule collector (19) is de- tachably mounted in the washing machine to be detached from the first posi- tion together with granules retained therein. 14. A device according to claim 7 and claim 8, wherein said granule collector (19) is rotatably mounted on a shaft (20) extending through the side walls (22). 15. A device according to claim 7, wherein a flow directing means (28) is provided over the granule collector (19). 16. A device according to claim 15, wherein the flow directing means (28) comprises a panel formed with through holes that are dimensioned to allow passage of granules through the panel and that are arranged vertically above the granule collector (19).

Inventors: ROGMARK BERTIL, ROGMARK, BERTIL
Applicants: NAT CONVEYOR CORP, ROGMARK BERTIL, NATIONAL CONVEYOR CORP., ROGMARK, BERTIL
Application year: 1999
Main classification: A47L15
IPC codes: A47L15