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
  • A47L15/24—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
• • 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
  • A47L15/42—Details
  • A47L15/44—Devices for adding cleaning agents; Devices for dispensing cleaning agents, rinsing aids or deodorants
  • A47L15/449—Metering controlling devices
• • 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
  • A47L2401/00—Automatic detection in controlling methods of washing or rinsing machines for crockery or tableware, e.g. information provided by sensors entered into controlling devices
  • A47L2401/30—Variation of electrical, magnetical or optical quantities
• • 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
  • A47L2501/00—Output in controlling method of washing or rinsing machines for crockery or tableware, i.e. quantities or components controlled, or actions performed by the controlling device executing the controlling method
  • A47L2501/07—Consumable products, e.g. detergent, rinse aids or salt

Definitions

• the invention relates to a metering method for supplying a cleaner to a dishwasher, which comprises: at least one cleaning tank, a conductivity sensor arranged in the cleaning tank, a spray device with return of the sprayed cleaning solution into the cleaning tank, and a metering device which feeds the cleaner into the cleaning tank.
• the dishwasher for which the dosing method of the present invention is intended is a so-called GSM commercial dishwasher, which is used, for example, in commercial kitchens.
• Such dishwashers have at least one cleaning tank that contains water. Water from the cleaning tank is fed by a pump to a spray device which sprays the water above the cleaning tank onto the dishes to be washed, the water then falling back into the cleaning tank.
• a detergent is supplied to the water in the cleaning tank by a metering device.
• the dosing device is controlled by a controller depending on the concentration of the cleaning agent in the cleaning tank. This concentration is from one Conductivity sensor determined. This takes advantage of the fact that - assuming constant temperatures - there is a large proportionality between the concentration of the cleaner and the resulting conductivity of the water.
• the conductivity controller compares the measured value supplied by the transmitter with a specified setpoint and activates a metering valve or a metering pump if the setpoint is undershot. When the setpoint is reached again, the metering valve or metering pump is switched off.
• the regulation of the metering of the detergent is influenced by a large number of parameters, for example the type and size of the dishwasher, the type and nature of the respective detergent and the water temperature.
• the dead time must also be taken into account, ie the time between the start of metering the cleaner and the metering becoming effective by increasing the conductivity.
• the intensity of the mixing also plays an important role here.
• Influencing factors that influence the concentration control are mechanical influences such as positioning of the detergent dosing point, positioning of the conductivity measuring cell in the cleaning tank, length of the rinsing line for powdered detergents, flow conditions in the washing liquor, and chemical influences such as solubility of the detergent product, conductivity / concentration behavior of the Detergent product.
• the invention has for its object to provide a metering method for supplying a cleaner to a dishwasher, in which achievable metering accuracy is significantly higher than in conventional controllers. This object is achieved according to the invention with the features specified in claim 1.
• the dosing method according to the invention is based on the use of fuzzy logic, which works with heuristic, vaguely formulated rules.
• fuzzy logic works with heuristic, vaguely formulated rules.
• Characteristic influencing variables of the controlled system are obtained from the system response resulting from the metering.
• the answer consists of a conductivity curve that arises due to the one-time addition. In a way, it is the step response of the train route. It determines certain influencing variables, for example the dead time, the change in concentration, the rate of compensation and / or the change in measured value.
• influencing variables of the controlled system are processed in the subsequent operating phase as a heuristic variable, ie as unsharp parameters of the controlled system, as part of a fuzzy control.
• a heuristic variable ie as unsharp parameters of the controlled system
• fuzzy control which takes place during the subsequent operating phase, only the measured conductivity value or the setpoint deviation is used as the measured variable, while the other influencing variables originate from the previous learning phase.
• a new learning phase is preferably carried out whenever the setpoint deviation exceeds one during the operating phase predetermined minimum time exceeds a limit. In this case, it is assumed that the assessment of the influencing variables carried out in the learning phase is no longer correct and must be carried out again.
• Fig. 1 is a schematic representation of a commercial product
• Fig. 3 is a schematic representation of the fuzzy controller
• Fig. 4 shows another embodiment of the metering part of a dishwasher, which is operated with liquid cleaner.
• the commercial dishwasher GSM shown in FIG. 1 has a conveyor line 10 which transports the dishes to be cleaned in the direction of arrow 11.
• the conveyor section 10 consists of a conveyor belt running over rollers, which is permeable to water.
• Under the conveyor section 10 there are a first cleaning tank 12, a second cleaning tank 13 and a third cleaning tank 14, which are arranged in the manner of a cascade, the water from the first cleaning tank 12 being above an overflow 15 overflows into the second cleaning tank 13. From the second cleaning tank 13, the water runs over an overflow 16 into the third cleaning tank 14 and from this the water is discharged into an outlet 17.
• the running direction of the water is opposite to the transport direction 11 of the conveyor line 10.
• a submersible pump 18 is arranged in each cleaning tank 12, 13, 14 and pumps the water from this cleaning tank to a spray device 19, which sprays the water onto the dishes lying on the transport device 10.
• the spray device 19 is arranged above the cleaning tank, which is open at the top, so that the water sprayed by it falls back into the cleaning tank.
• a rinsing device 20 is arranged above the end section of the conveyor 10 and sprays fresh water, which does not come from any of the cleaning tanks, onto the dishes. Below the rinsing device 20 there is an oblique drain plate 21 which collects the fresh water and directs it into the first cleaning tank 12. The dirt load of the water increases continuously from the first cleaning tank 12 to the third cleaning tank 14.
• Cleaner is introduced into the first cleaning tank 12 by a metering device 22 via a metering line 23.
• the metering device 22 is connected to a water line 24 and contains a valve 25 which can be opened by an electromagnet 26 in order to introduce fresh water into a powder container 27.
• the powder container 27 contains powdered cleaner, which in the inflowing water is dissolved.
• the outlet of the powder container 27 is connected to the metering line 23.
• the concentration of detergent in the water which is in the first cleaning tank 12 is determined by a conductivity sensor 28 which is arranged in the first cleaning tank 12 and measures the conductivity of the water. There is extensive proportionality between the detergent concentration in the water and the measured conductivity.
• the electrical output signal of the sensor 28 is fed to a controller 29 which actuates the electromagnet 26 of the valve 25 as a function of the measured value.
• the valve 25 is only operated in the on-off mode.
• FIG. 2 shows an example of a response of the measuring signal x from the measuring sensor 28 to a metering pulse I, which was generated by the metering device 22 and in which the valve 25 was opened over a predetermined time t v in order to supply the cleaning tank 12 with detergent.
• a dead time T "elapses before the cleaner causes any effects on the sensor 28. This dead time takes into account the opening behavior of the valve 25, the duration of the solution of the powdered detergent in the powder container 27 and the running time of the liquid detergent solution in the metering line 23.
• the dead time T t has ended and an initially steep increase in conductivity begins to a point B, at where the measured value is x B.
• This tip can be attributed to the fact that the cleaner entering the cleaning tank 12 first comes close to the sensor 28 before it is distributed in the bath. This is followed by a drop in the measured value to a point C and finally a slow asymtotic rise to the compensation value D, which represents the last maximum of the curve. This increase is due to the fact that mixing takes place in the cleaning tank during the mixing time T M after the dead time T.
• the difference between the measured value x D at the point in time D and the measured value x A at the point in time when the metering takes effect is called the change in concentration KD.
• the compensation speed is determined by the time T M between points A and D of the response curve.
• the change in measured value MD is also determined.
• the change in the measured value is determined by the slope of the response curve between points A and B.
• the cleaning liquor is diluted by the water which reaches the cleaning tank 12 through the rinsing device 20 or through another water inlet. This water supply takes place continuously both during the learning phase and during the operating phase.
• the rate of dilution W is determined by the gradient of the drop in the response curve following point D.
• the submersible pump 18 and the spray device 19 are also in operation.
• the influencing variables determined from the response curve during the learning phase are therefore the following:
• the controller 29 is shown schematically. It is a fuzzy controller in which the influencing variables explained above are fuzzified.
• certain membership functions MF were defined for each influencing variable. These are triangular curves or trapezoidal curves which divide the different ranges of the values of the influencing variables into semantic terms such as "very high”, “high”, “medium”, “low” and “very low”.
• the corresponding membership value is determined in the membership function MF for the determined value of the influencing variable.
• An interference stage contains various "IF ..., THEN " links of the various influencing variables and finally there is a defuzzification in which the control signal for the metering device 22 is generated.
• the linguistic variables according to rules 1 to 5 are determined and saved during the learning phase. They remain unchanged during an operating phase.
• the variable according to rule 6 is continuously determined during the operating phase and the metering device 22 is controlled as a function of its chronological course.
• the measured value x of the transmitter 28 is fed to the fuzzy controller 29, as well as the setpoint x s to which the conductivity is to be regulated.
• the setpoint deviation Dx x - x s is formed from these two values.
• the output signal of the fuzzy controller 29 can assume the following states:
• the metering device 22a contains a pump 30 which pumps liquid detergent from a liquid container 31 into the metering line 23.
• the controller 29 controls the pump 30 by either switching it on or off.

Landscapes

• Washing And Drying Of Tableware (AREA)
• Detergent Compositions (AREA)
• Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=7815170

Family Applications (1)

Country Status (13)

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Family Cites Families (6)

• 1996
  • 1996-12-18 DE DE19652733A patent/DE19652733C2/de not_active Expired - Lifetime
• 1997
  • 1997-12-10 EP EP97954371A patent/EP0946121B1/fr not_active Expired - Lifetime
  • 1997-12-10 JP JP52726798A patent/JP4001391B2/ja not_active Expired - Lifetime
  • 1997-12-10 DK DK97954371T patent/DK0946121T3/da active
  • 1997-12-10 US US09/331,379 patent/US20020117187A1/en not_active Abandoned
  • 1997-12-10 AT AT97954371T patent/ATE195062T1/de not_active IP Right Cessation
  • 1997-12-10 NZ NZ336803A patent/NZ336803A/xx not_active IP Right Cessation
  • 1997-12-10 ES ES97954371T patent/ES2150293T3/es not_active Expired - Lifetime
  • 1997-12-10 DE DE59702115T patent/DE59702115D1/de not_active Expired - Fee Related
  • 1997-12-10 PT PT97954371T patent/PT946121E/pt unknown
  • 1997-12-10 CA CA002275388A patent/CA2275388A1/fr not_active Abandoned
  • 1997-12-10 WO PCT/EP1997/006888 patent/WO1998026704A1/fr not_active Ceased
• 1999
  • 1999-06-17 NO NO992955A patent/NO992955D0/no not_active Application Discontinuation
• 2000
  • 2000-09-05 GR GR20000402014T patent/GR3034327T3/el not_active IP Right Cessation

Non-Patent Citations (1)

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