Additive metering control system

A control system for metering the amount of a dry additive discharged from a dry additive metering container, which metering container is associated with a dry additive inventory container, and for metering the amount of a liquid additive discharged from a liquid additive container, which discharged amounts are for mixing with a primary substance discharged from a primary substance container, said system comprising:

• means for determining the amount of the dry additive being discharged from the dry additive metering container;
• means for determining the amount of the liquid additive being discharged from the liquid additive container;
• means for sensing the amount of the primary substance being discharged from the primary substance container;
• means, responsive to said dry additive determining means, said liquid additive determining means, and said primary substance sensing means, for controlling the amount of the dry additive being discharged from the dry additive metering container and for controlling the amount of the liquid additive being discharged from the liquid additive container;
• and
• said means for sensing the amount of the primary substance including:
• means for generating a first voltage level proportional to the flow rate of the sensed primary substance;
• means for simulating a flow rate of the primary substance by generating a second voltage level representing the simulated flow rate;
• and
• means for switchably communicating said first voltage generating means and said simulating means with said controlling means.

A method of metering additives to be blended with a primary substance in a system having a dry additive stored in a dry additive inventory container associated with a dry additive metering container and also having a liquid additive stored in a liquid additive container, said method comprising the steps of:

• receiving data pertaining to concentrations of the dry additive and the liquid additive to be obtained in the blending thereof with the primary substance, to density of the dry additive, and to first required flow rates of the dry additive and the liquid additive;
• determining if said method is to be performed in an automatic mode or a manual mode;
• testing the flow rate of the primary substance;
• monitoring the actual flow rate of the liquid additive as it is discharged from the liquid additive container;
• calculating a second required liquid additive flow rate using the concentration data and the flow rate of the primary substance;
• normalizing the actual and the first and second required liquid additive flow rates;
• subtracting the normalized actual liquid additive flow rate from the normalized second required liquid additive flow rate when the method is performed in the automatic mode;
• subtracting the normalized actual liquid additive flow rate from the normalized first required liquid additive flow rate when the method is performed in the manual mode;
• generating a liquid additive error signal from the result of the operative one of said subtracting steps;
• controlling the discharge rate of the liquid additive in response to the liquid additive error signal;
• evaluating the weight of the dry additive stored in the dry additive inventory container;
• determining if the dry additive metering container is being filled with the dry additive;
• calculating a second required dry additive discharge rate using the concentration data and the flow rate of the primary substance;
• computing the change in weight of the dry additive in the dry additive metering container over a predetermined period of time to thereby obtain an actual dry additive discharge rate;
• normalizing the actual and the first and second required dry additive discharge rates;
• subtracting the normalized actual dry additive discharge rate from the normalized second required dry additive discharge rate when the method is performed in the automatic mode;
• subtracting the normalized actual dry additive discharge rate from the normalized first required dry additive discharge rate when the method is performed in the manual mode;
• generating a dry additive error signal from the results of the operative one of said subtracting steps;
• and
• controlling the dry additive discharge rate in response to the dry additive error signal.

An additive metering control system, comprising:

• an additive container;
• means for causing mechanical vibrations in said additive container;
• additive determining means for determining the amount of an additive being discharged from said additive container, said additive determining means including:
• means for detecting the weight of the additive and the mechanical vibrations and for generating an electrical signal proportional to the detected weight, said electrical signal having a frequency component within a predetermined range of frequencies in response to the detected mechanical vibrations;
• and
• filter means for removing from said electrical signal said frequency component created by the detected mechanical vibrations;
• primary substance sensing means for sensing the amount of a primary substance being discharged from a primary substance container;
• and
• means, responsive to said additive determining means and said primary substance sensing means, for controlling the amount of additive being discharged from said additive container.

A control system for metering the amount of a dry additive discharged from a dry additive metering container, which dry additive metering container is associated with a dry additive inventory container, and for metering the amount of a liquid additive discharged from a liquid additive container, which discharged amounts are for mixing with a primary substance discharged from a primary substance container, said system comprising:

• means for determining the amount of the dry additive being discharged from the dry additive metering container, said means including:
• hydraulic load cell means associated with the dry additive metering container for detecting the weight of the metering container and the dry additive contained therein and for generating a first electrical signal proportional to the detected weight;
• electronic filter means for filtering a predetermined range of frequencies from the first electrical signal;
• means for converting the filtered first electrical signal into a digitally-coded format;
• and
• first memory means for storing the digitally-coded first electrical signal;
• means for determining the amount of liquid additive being discharged from the liquid additive container;
• means for sensing the amount of the primary substance being discharged from the primary substance container;
• and
• means, responsive to said digitally-coded first electrical signal, said liquid additive determining means, and said primary substance sensing means, for controlling the amount of the dry additive being discharged from the dry additive metering container and for controlling the amount of the liquid additive being discharged from the liquid additive container.

A metering control system for controlling the amount of a liquid additive discharged from a liquid additive container into a primary substance, comprising:

• means for determining the amount of the liquid additive being discharged from the liquid additive container, said liquid additive determining means including:
• means for monitoring the actual flow rate of the additive and for generating an electrical signal proportional to the monitored actual flow rate;
• means for converting the electrical signal into a digitally-coded format;
• and
• means for electronically retaining the digitally-coded signal;
• means for sensing the amount of the primary substance being discharged from a primary substance container;
• and
• means, responsive to the digitally-coded signal in said electronic retaining means and to said primary substance sensing means, for controlling the amount of the liquid additive being discharged from the liquid additive container, said controlling means including:
• central processing means for generating liquid container control data;
• means for discharging the liquid additive from the liquid additive container;
• and
• data bus means connecting said central processing means to said discharging means so that said liquid container control data can be transmitted to said discharging means.