Classifications

• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L15/00—Washing or rinsing machines for crockery or tableware
  • A47L15/42—Details
  • A47L15/44—Devices for adding cleaning agents; Devices for dispensing cleaning agents, rinsing aids or deodorants
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L15/00—Washing or rinsing machines for crockery or tableware
  • A47L15/0018—Controlling processes, i.e. processes to control the operation of the machine characterised by the purpose or target of the control
  • A47L15/0055—Metering or indication of used products, e.g. type or quantity of detergent, rinse aid or salt; for measuring or controlling the product concentration
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L15/00—Washing or rinsing machines for crockery or tableware
  • A47L15/24—Washing or rinsing machines for crockery or tableware with movement of the crockery baskets by conveyors
  • A47L15/241—Washing or rinsing machines for crockery or tableware with movement of the crockery baskets by conveyors the dishes moving in a horizontal plane

Definitions

• This invention relates to a machine dishwashing process; more particularly, it relates to an improvement in continuous or non-continuous machine dishwashing, whether conducted using a single tank, multitank or conveyor type machine.
• tableware or cookware such as dishes soiled with food remains, trays, cutlery and lipstick-smeared glasses, is intensively sprayed with water in a prewash zone or prewash cycle.
• the water used for the prewash may be cold or preheated fresh water or cooling water from a vapour condensation process, but is generally overflow water of a wash liquor, which is generally sprayed onto the articles under relatively low pressure and in relatively large amounts using suitably located spray nozzles.
• the articles enter the actual wash zone or wash cycle, where they are again vigorously sprayed this time with a wash liquor.
• the wash liquor is generally water at a temperature of from 50 to 60°C to which a liquid or powder-form detergent is added.
• a liquid or powder-form detergent is added to water to provide from 0.1 to 0.3 weight percent of active cleaning agent in solution.
• This resulting wash liquor is sprayed onto the articles by pump means through lower and upper nozzles and, in some cases, through additional lateral nozzles.
• the soil present on the articles is removed or at least swollen or softened and partially dissolved by the wash liquor. In following rinse zones or cycles, the swollen or softened food remains are removed and, at the same time, the wash liquor is rinsed off by water.
• any residues of the wash liquor are removed by water at a temperature of up to about 85°C.
• the final-rinse water consists of fresh water with an added rinse aid, which ensures that only an ultrathin film of water remains on the articles, which can evaporate in a following drying zone.
• An object of the present invention is to provide surprisingly advantageous dishwashing.
• the improved efficiency of cleaning obtainable may reduce labour, water and chemical consumption, hence lower pollution and rejects, while ensuring satisfactory cleaning even in adverse conditions.
• the present invention provides a machine dishwashing process characterised in that a highly concentrated aqueous cleaning formulation is sprayed onto at least partially soiled articles and, after a contact time, the cleaning formulation and soil are removed in one or more subsequent stages.
• the present invention also provides a dishwashing machine adapted to effect such a process, for example by addition of extra spray nozzles and associated systems and/or by modifications to the control systems of the machine.
• the aqueous cleaning formulation may be derived from powder-form or liquid materials.
• the sprayed cleaning formulation comprises at least 0.5 weight percent of one or more active cleaning agents. While, say, 30 weight percent might be regarded as an upper limit, the critical factor is that the formulation must remain sprayable.
• the sprayed cleaning formulation comprises from 0.8 to 10 weight percent, more preferably from 0.9 to 3 weight percent, of one or more active cleaning agents.
• a contact time of at least 2 seconds will be sufficient for the desired chemical, as opposed to mechanical, action. In preferred embodiments, this may be from 5 to 100 seconds, in particular from 8 to 25 seconds. So as to provide the desired prolonged intimate contact or “saturation", the "mechanical effect" of spraying is at least minimised, if not avoided. During this contact time, the articles being washed are not deliberately sprayed.
• a fine, gentle mist-like spray is particularly desirable.
• the belt speed will also be a factor.
• the volume sprayed and/or the number and/or arrangement of spray nozzles is/are selected so that low volume spraying will ensure the desired type of complete coverage and even distribution.
• the nature, volume and concentration of the sprayed formulation may be varied, as may the spray means, depending, for example, on the load and, where appropriate, the motion and/or speed of the conveyor.
• the present low volume/low intensity mist-like application of concentrated cleaning formulation is in contrast to the vigorous high volume spraying used in conventional dishwashing.
• a machine dishwashing process may comprise one or more prewash cycles or zones, which may be optional, for example to remove heavy soil, one or more wash zones and one or more rinse zones.
• the unusually high concentration cleaning solution is sprayed somewhere prior to the final rinse, commonly as at least part of a wash cycle or in a wash zone.
• cleaning agents While all of the cleaning agents required may be included in the sprayed concentrate, it may be advantageous to introduce additional cleaning formulation in a conventional manner at some stage of the process.
• This further material is generally not the same as the sprayed concentrate, but may merely be the same composition further diluted.
• the present system also enables chemicals which would normally be incompatible when mixed in a single product to be used in conjunction, for example oxidising agents, such as hypochlorite, may be used in the spray with, for example, water conditioning agents, such as NTA (nitrilotriacetate) being introduced later.
• oxidising agents such as hypochlorite
• water conditioning agents such as NTA (nitrilotriacetate) being introduced later.
• the concentrated cleaning formulation is generally sprayed more or less throughout the appropriate part of the dishwashing process, it may be used intermittently or occasionally, for example during the wash cycle in a non-conveyor type machine.
• the aqueous cleaning formulation sprayed must be flowable, but may be in the form of a solution, emulsion or slurry, for example.
• a basic cleaning formulation will comprise a source of alkalinity and a source of sequestering activity.
• Such formulations may be adapted to combat particular problems. For example, tea-stain removal might suggest the inclusion of bleaching agents, while products based on amylase may be useful for starch removal without alkalinity.
• a machine for carrying out the present process may be a conveyor transport machine and may comprise a prewash zone, a wash zone, a rinse zone, a final rinse zone and a drying zone. Fresh water is only supplied to the final-rinse zone, subsequently passing cascade-fashion towards the prewash zone in countercurrent to the direction of transport of the dishes.
• a simple product fairly efficient in removing built-up starch residues and stains may be formulated from the following : Potassium hydroxide 20 - 30 wt % Chelating agent(s) 15 - 25 wt % Threshold agent(s) 2 - 4 wt % Dispersing polymer(s) 2 - 4 wt % Wetting agent(s) 1 - 2 wt % Balance water
• Such a product may be blended with water in-­line before being sprayed at a dilution of about 2.5 % through suitable spray nozzles situated within the wash zone immediately before or after the conventional wash zone. Sprayed ware may then pass through part of the wash zone with the pumps turned off (unless there is already sufficient separation between zones) so as to allow a contact time of about 15 seconds, before reaching a further wash or rinse zone. Further detergent may be added by conventional means at other stages to provide additional destaining and prevention of incrustation of machine parts. Thereafter, the ware passes to a final rinse stage where rinse aid may be introduced.
• each nozzle may be delivering as little as 6 1/hour and typically there will be from 3 to 10 nozzles.
• the system is arranged or adapted to ensure that nothing disturbs the desired prolonged intimate contact.
• the speed of the conveyor belt is advantageously selected so that the contact time of the detergent solution, depending on its concentration, is from 5 to 100 seconds, generally about 10 seconds.
• Such a contact time and the high concentration of the detergent solution ensure that all food remains on the dishes, especially grease (fats), starch, stains and protein, are completely removed and bacteria destroyed.
• the detached food remains, together with the detergent solution sprayed on, are washed off by the subsequent stages using conventional spray nozzles, the wash liquor consisting of overflow water from the rinse zone and of rinsed-off, concentrated detergent solution and any additional dosed complementary cleaning formulation.
• the wash liquor consisting of overflow water from the rinse zone and of rinsed-off, concentrated detergent solution and any additional dosed complementary cleaning formulation.
• any loosened food and soil remains still present on the dishes and residues of the wash liquor are rinsed off with clear water at a temperature of about 70°C.
• clear water at a temperature of about 70°C.
• fresh water at a temperature of about 85°C with rinse aid added ensures that only a thin film of water remains on the dishes, which dries rapidly in the following drying zone either through the heat of the dishes or by introduction of hot air.

Landscapes

• Detergent Compositions (AREA)
• Washing And Drying Of Tableware (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (3)

Family

ID=6322513

Family Applications (1)

Country Status (6)

Cited By (18)

Families Citing this family (18)

Citations (19)

Family Cites Families (5)

• 1987
  • 1987-03-07 DE DE19873707366 patent/DE3707366A1/de not_active Ceased
• 1988
  • 1988-03-01 EP EP88301755A patent/EP0282214B2/de not_active Expired - Lifetime
  • 1988-03-01 DE DE8888301755T patent/DE3865324D1/de not_active Expired - Lifetime
  • 1988-03-01 CA CA000560223A patent/CA1324945C/en not_active Expired - Lifetime
  • 1988-03-01 ES ES88301755T patent/ES2026250T5/es not_active Expired - Lifetime
  • 1988-03-02 AU AU12576/88A patent/AU604854B2/en not_active Expired
  • 1988-03-03 DK DK198801148A patent/DK171583B2/da not_active IP Right Cessation

Patent Citations (19)

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