US 5,500,050 A · Ratio feed detergent controller and method with automatic feed rate learning capability

Abstract

A detergent dispenser controller for use with a washing device, such as a dishwasher, that measures detergent concentration in a water tank by measuring the conductivity of the detergent solution in the water tank. The detergent controller automatically learns the feed rate of the detergent dispenser used, regardless of the type of detergent dispenser being used. For each detergent feed cycle, the controller computes a Feed Factor equal to the amount of detergent feed on time required for each unit increase in the detergent concentration, which is the inverse of the detergent feed rate. The controller stores the computed Feed Factor for the last N feed cycles in a non-volatile memory, and computes a running average of the N feed factors stored in the non-volatile memory. Whenever the detergent dispenser is powered on, it determines the difference between the measured wash tank detergent concentration and a specified detergent concentration set point value. The computed average feed factor and the difference between the set point and the current detergent concentration are multiplied to compute a detergent feed on time. The detergent dispenser is then turned on for the computed feed on time, and after a suitable subsequent mixing period, the change in detergent concentration during the last feed cycle is determined and a new Feed Factor is computed and stored. The detergent concentration is preferably measured using logarithmic measurement units, and separate Feed Factors may be computed and used for at least two detergent concentration ranges.

Claims32

Dependent claims

A detergent dispenser controller for use in conjunction with a detergent dispenser that dispenses detergent from a detergent supply into a dishwasher and a conductivity sensor that generates signals corresponding to detergent concentration in a wash tank in the dishwasher, the controller comprising:

a non-volatile memory;
dispenser control circuitry coupled to said detergent dispenser;
an analog to digital converter coupled to said conductivity sensor for converting said conductivity sensor generated signals into digitized conductivity values;
and
a data processor coupled to said non-volatile memory and said dispenser control circuitry and said analog to digital converter, said data processor including control programming executed by said data processor for:
(A) enabling operation of said detergent dispenser for periods (detergent dispensing periods) of time separated by detergent mixing periods during which operation of said detergent dispenser is disabled;
(B) storing digitized detergent concentration values corresponding to said digitized conductivity values, including digitized detergent concentration values associated with said detergent's concentration before and after each said detergent dispensing period, and computing a first detergent concentration differential value based on said digitized detergent concentrations after and before said chemical dispensing period;
(C) for each of at least a subset of said periods during which said detergent dispenser is enabled, generating a detergent feed factor corresponding to the ratio of each said detergent dispensing period of time to said first detergent concentration differential;
(D) storing said detergent feed factor in said non-volatile memory;
(E) computing an average of said detergent feed factors for a predefined number of said detergent dispenser periods;
(F) computing a second detergent concentration differential value corresponding to a detergent concentration set point and said digitized conductivity value prior to each detergent dispensing period;
(G) computing a feed time value corresponding to said average detergent feed factor and said second detergent concentration differential value;
(H) enabling operation of said detergent dispenser for said computed feed time value;
and
(I) disabling operation of said detergent dispenser whenever said digitized conductivity value corresponds to a detergent concentration at or above said detergent concentration set point.

12 more elements

A method of controlling a detergent dispenser that dispenses detergent from a detergent supply into a dishwasher, wherein the dishwasher includes a conductivity sensor that generates signals corresponding to detergent concentration in a wash tank in the dishwasher, the method comprising the steps of:

converting said conductivity sensor generated signals into digitized conductivity values;
using a programmed digital data processor, performing the steps of:
(A) enabling operation of said detergent dispenser for periods (detergent dispensing periods) of time separated by detergent mixing periods during which operation of said detergent dispenser is disabled;
(B) storing digitized detergent concentration values corresponding to said digitized conductivity values, including digitized detergent concentration values associated with said detergent's concentration before and after each said detergent dispensing period, and computing a first detergent concentration differential value based on said digitized detergent concentrations after and before said chemical dispensing period;
(C) for each of at least a subset of said periods during which said detergent dispenser is enabled, generating a detergent feed factor corresponding to the ratio of each said detergent dispensing period of time to said first detergent concentration differential;
(D) storing said detergent feed factor in a non-volatile memory;
(E) computing an average of said detergent feed factors for a predefined number of said detergent dispenser periods;
(F) computing a second detergent concentration differential value corresponding to a detergent concentration set point and said digitized conductivity value prior to each detergent dispensing period;
(G) computing a feed time value corresponding to said average detergent feed factor and said second detergent concentration differential value;
(H) enabling operation of said detergent dispenser for said computed feed time value;
and
(I) disabling operation of said detergent dispenser whenever said digitized conductivity value corresponds to a detergent concentration at or above said detergent concentration set point.

9 more elements

A chemical dispenser controller for use in conjunction with a chemical dispenser that dispenses a chemical into a receiving device and a concentration sensor that generates signals corresponding to said chemical's concentration in the receiving device, the controller comprising:

a non-volatile memory;
dispenser control circuitry coupled to said chemical dispenser;
a signal receiver that receives said concentration sensor generated signals;
a data processor coupled to said non-volatile memory, said dispenser control circuitry and said signal receiver, said data processor including control programming executed by said data processor for:
(A) enabling operation of said chemical dispenser for periods of time (chemical dispensing periods) separated by chemical mixing periods during which operation of said chemical dispenser is disabled;
(B) storing digitized concentration values corresponding to said received concentration sensor generated signals, including digitized concentration values associated with said chemical's concentration before and after each said chemical dispensing period, and computing a first chemical concentration differential value based on said digitized concentrations values after and before said chemical dispensing period;
(C) for each of at least a subset of said chemical dispensing periods, generating a chemical feed factor corresponding to the ratio of each said chemical dispensing period of time to the change, if any, in said chemical concentration during said chemical dispensing period;
(D) storing said chemical feed factor in said non-volatile memory;
(E) computing an average of said chemical feed factors for a predefined number of said chemical dispenser periods;
(F) computing a second chemical concentration differential value corresponding to a chemical concentration set point and said digitized concentration value prior to each chemical dispensing period;
(G) computing a feed time value corresponding to said average chemical feed factor and said second chemical concentration differential value;
(H) enabling operation of said chemical dispenser for said computed feed time value;
and
(I) disabling operation of said chemical dispenser whenever said digitized concentration value corresponds to a chemical concentration at or above said chemical concentration set point.

11 more elements

A method of controlling a chemical dispenser that dispenses chemical from a chemical supply into a receiving device, wherein the receiving device includes a concentration sensor that generates signals corresponding to chemical concentration in the receiving device, the method comprising the steps of:

receiving said concentration sensor generated signals;
using a programmed digital data processor, performing the steps of:
(A) enabling operation of said chemical dispenser for periods (chemical dispensing periods) of time separated by chemical mixing periods during which operation of said chemical dispenser is disabled;
(B) storing digitized chemical concentration values corresponding to said received concentration sensor generated signals, including digitized chemical concentration values associated with said chemical's concentration before and after each said chemical dispensing period, and computing a first chemical concentration differential value based on said digitized chemical concentrations after and before said chemical dispensing period;
(C) for each of at least a subset of said periods during which said chemical dispenser is enabled, generating a chemical feed factor corresponding to the ratio of each said chemical dispensing period of time to said first chemical concentration differential;
(D) storing said chemical feed factor in a non-volatile memory;
(E) computing an average of said chemical feed factors for a predefined number of said chemical dispenser periods;
(F) computing a second chemical concentration differential value corresponding to a chemical concentration set point and said digitized concentration value prior to each chemical dispensing period;
(G) computing a feed time value corresponding to said average chemical feed factor and said second chemical concentration differential value;
(H) enabling operation of said chemical dispenser for said computed feed time value;
and
(I) disabling operation of said chemical dispenser whenever said digitized concentration value corresponds to a chemical concentration at or above said chemical concentration set point.

9 more elements

Dependencies are inferred from the claim text.

Ratio feed detergent controller and method with automatic feed rate learning capability

Life of this patent

Ratio feed detergent controller and method with automatic feed rate learning capability

Life of this patent

Abstract

Claims32