Automated chemical metering system and method

A system for controlling the amount of a chemical pesticide injected into a flow stream, said system comprising:

• a mixing tank containing a mixture, in known proportions, of the chemical pesticide to be injected and an inert fluorescent dye;
• a peristaltic pump for injecting said mixture into said flow stream at a first location therealong;
• a controller for controlling the operation of said pump;
• detection means located at a second location downstream from said first location and including a fluorometer, for obtaining a sample of said flow stream at said second location and for producing an output signal related to the amount of said inert fluorescent dye in said sample;
• and
• means for connecting said detection means to said controller so that the controller controls the operation of said pump in accordance with said output signal.

A method of controlling the amount of a chemical introduced into a flow stream, said method comprising:

• creating a combination by mixing, in a known proportion, said chemical and an inert indicator;
• injecting an amount of said combination into said flow stream at an input point;
• determining the amount of said inert indicator in said flow stream at a location downstream from said input point;
• determining from the amount of said indicator in said flow stream the amount of said chemical in said flow stream;
• and
• adjusting, as necessary, the amount of said chemical in said flow stream by altering the amount of said combination injected into said flow stream based on the determined amount of said chemical.

A method of determining the flowrate of a flow stream, said method comprising:

• producing a substance-indicator combination by mixing a substance and an inert indicator in known proportions;
• injecting, at a known injection rate, an amount of said combination into said flow stream at an input point;
• determining the concentration of said indicator in said flow stream at a location downstream of said input point;
• comparing the concentration of said inert indicator in said flow stream with the known proportion of said inert indicator in the combination being injected so as to determine a multiplying factor;
• and
• multiplying the known injection rate by said multiplying factor to determine the flowrate of the flow stream.

A system for controlling the amount of a chemical pesticide injected into flowing water in a water channel in an outdoor environment, said system comprising:

• a mixing tank containing a mixture, in known proportions, of the chemical pesticide to be injected and a fluorescent dye;
• a first, peristaltic pump for injecting said mixture into the water of the water channel at a first location therealong;
• a controller for controlling the operation of said pump;
• a second, sampling pump, located at a second location along the water channel downstream from said first location, for obtaining a sample of the water in the water channel at said second location,
• a fluorometer connected to said sampling pump for receiving said sample from said sampling pump and for producing an output signal related to the amount of dye in said sample;
• and
• means for connecting said fluorometer to said controller so that the controller controls the operation of said first pump in accordance with said output signal.