Industrial dishwasher chemical dispenser

In a dishwasher system having conductivity measuring means for measuring the conductivity of wash water used by said system, a detergent dispenser for adding detergent to wash water used by said system, and a rinse agent dispenser for adding rinse agent to rinse water used by said system,

• a dispenser controller coupled to said conductivity measuring means, detergent dispenser and rinse agent dispenser comprising:
• concentration selection means for selecting a target dish water detergent concentration level which is calibrated in predefined logarithmically scaled units providing proportionally uniform resolution over a predefined range of selectable concentration levels;
• comparison means for converting the conductivity measurements obtained by said conductivity means into detergent concentration measurements calibrated in said predefined logarithmically scaled units, and for comparing said target concentration level with said detergent concentration measurements;
• and
• detergent dispenser control means, responsive to said comparison means, for turning said detergent dispenser on and off in response to the relative levels of said detergent concentration measurements and said target dish water detergent concentration level;
• and
• means for determining the rate of increase of said detergent concentration measurements, and means for denoting a detergent feeding failure when said rate of increase remains, for a first predefined period of time, less than the rate required to increase said detergent concentration to said target dish water detergent concentration level within a second predefined period of time;
• wherein said first predefined period of time is shorter than said second predefined period of time;
• whereby a detergent feeding failure can be quickly detected by detecting when the rate of increase of detergent concentration is too low to reach said specified target level.

In a dishwasher system having water routing means for receiving wash water and rinse water to be used by said system, ion concentration measuring means for measuring the conductivity of the wash water used by said system, a detergent dispenser for adding detergent to the wash water used by said system, and a rinse agent dispenser for adding rinse agent to the rinse water used by said system, a controller comprising:

• concentration selection means for selecting a target dish water detergent concentration level which is calibrated in predefined logarithmically scaled units, wherein each logarithmically scaled unit corresponds to a predefined percentage change in the conductivity of said system's wash water;
• comparison means for comparing said target concentration level with the conductivity level measured by said ion concentration measuring means;
• dishwasher type selection means for specifying whether said dishwasher system is a batch or conveyor mode dishwasher system;
• and
• logic means, responsive to an indication from said dishwasher type selection means that said dishwasher system is a batch mode dishwasher system, for preventing the dispensing of detergent into the wash water used by said system during rinse cycles even when the conductivity level measured by said ion concentration measuring means is less than said selected target concentration level level, and for limiting the dispensing of rinse agent to a predefined portion of said system's rinse cycle.

In a dishwasher system having means for receiving wash water to be used by said system, ion concentration measuring means for measuring the conductivity of the wash water used by said system, and a detergent dispenser for adding detergent to the system's wash water, a detergent dispenser controller including:

• means for specifying a target dish water conductivity level;
• and
• detergent feeding failure detection means for determining the rate of increase of said conductivity level measured by said ion concentration measuring means, and for denoting a detergent feeding failure when said rate of increase remains, for a first predefined period of time, less than the rate required to increase said conductivity level to said target conductivity level within a second predefined period of time;
• wherein said first predefined period of time is shorter than said second predefined period of time;
• whereby a detergent feeding failure can be quickly detected by detecting when the rate of increase of the wash water conductivity is too low to reach said specified target level within a predetermined amount of time.