Cleaning and liquid contact with solids – Apparatus – With plural means for supplying or applying different fluids...
Patent
1992-03-26
1993-08-31
Coe, Philip R.
Cleaning and liquid contact with solids
Apparatus
With plural means for supplying or applying different fluids...
134199, A47L 1516, A47L 1544
Patent
active
052400190
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND
1. Field of the Invention
This invention relates generally institutional dishwashing machines, and more specifically to such machines comprising a circuit for a detergent solution which is highly concentrated in relation to the wash liquor, and which is pump-circulated in a wash zone through the machine load.
2. Discussion of Related Art
In the context of the invention, the expression "machine load" or "dishes" is meant to encompass all the articles to be washed in dishwashing machines, more particularly plates, cups, cutlery and the like. Whereas normal wash liquor typically contains approximately 2 to 6 g detergent per liter of water, a "highly concentrated" detergent solution is one which contains approximately 30 to 80 g detergent per liter water. In institutional dishwashing machines (or IDWMS for short), the machine load is transported, for example on a belt, through various successive zones, more particularly a prerinse zone, a wash zone and a final-rinse zone.
In one known process for washing soiled dishes in a dishwashing machine comprising a wash zone, the prerinsed dishes are treated in the wash zone with a separately circulated, highly concentrated detergent solution. The detergent solution flowing down from the dishes flows into a collecting tank and from there to an external collecting tank or stock liquor container which is followed by a circulating pump supplying the circuit of the detergent solution. In the stock liquor container, the detergent solution is temporarily stored in the circuit. The concentration and amount of detergent solution in the circuit are also restored by controlling the solution in the stock liquor container. This requires sensors and corresponding feed pipes for fresh water and detergent concentrate.
EP-A-0 282 214 describes a process in which highly concentrated detergent solution is sprayed onto the dishes to be washed. This process is carried out in standard dishwashing machines in which a so-called spray arc is installed for spraying the highly concentrated detergent solution. The highly concentrated detergent solution is not collected or circulated separately in a circuit. Accordingly, there is no system separation between the highly concentrated detergent solution and the normally concentrated wash liquor although this would be desirable, for example for further minimizing the consumption of detergent.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an institutional dishwashing machine in which the detergent solution is transported in highly concentrated form in the wash zone in a circuit comprising a pump/spray system, i.e. in a circulatory process parallel to the normal washing process, without any need for a controlled regulating system for making up losses of liquid from the circuit during spraying of the dishes, i.e. without any need for a collecting tank outside the machine.
In one embodiment of the present invention, a dishwashing machine includes a circuit for a highly concentrated detergent solution which leads through the machine load and through a collecting trough, a system for controlling the level in the collecting trough consisting of an opening which is provided with a one-way or non-return flap, which is permeable towards the collecting trough and which leads to a metering tank accommodating the wash liquor, and by a system for controlling the concentration of the detergent solution via control of a metering pump integrated into the circuit.
The one way or non-return flap valve acts like a sluice way between the metering tank accommodating the normally metered wash liquor and the collecting trough accommodating the highly concentrated detergent solution, whereby wash liquor will flow from the metering tank into the collecting trough as long as a predetermined minimum level is not exceeded in the collecting trough. If, by contrast, the liquid in the collecting trough rises above a predetermined level, the sluice-like opening is closed by the pressure of the detergent solution. A "sluice" is basically an a
REFERENCES:
patent: 3144872 (1964-08-01), Kearney
patent: 3457929 (1969-07-01), Madden
patent: 4190481 (1980-02-01), Goffredo
patent: 4211517 (1980-07-01), Schmid
Coe Philip R.
Henkel Kommanditgesellschaft auf Aktien
Jaeschke Wayne C.
Szoke Ernest G.
Watov Kenneth
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