Abstract: A supply tube isolation system for use with a chemical delivery system includes a feedback tube connected between the manifold and each of the supply tubes connected between the chemical supply containers and the chemical pumps of the chemical delivery system. A controllable valve means is provided at or near the junction of the feedback tube and the supply tube so as to effectively segment the supply tube into first and second portions, where the first supply tube portion is that which is connected between the valve means and the manifold, and the second tube portion is that which is connected between the valve means and the chemical supply container. During delivery of the chemical to one or more destinations within the delivery system, the valve means is positioned so as to close the feedback tube and connect the first and second portions of the supply tube.

Abstract: A chemical dispensing system controller is used in conjunction with a mechanism for dispensing specified chemicals and a device that transmits trigger signals to the control system for requesting chemicals to be dispensed. The controller receives and accumulates sequences of the transmitted trigger signals. Each trigger signal sequence is preceded and followed by a period of time of predefined duration during which no trigger signals are received. At least some of the trigger signals in some of the trigger signal sequences are not received simultaneously. Also, the number of distinct chemical feed requests that can be communicated using the accumulated trigger signals exceeds the number of distinct trigger signals. The controller maps a first subset of the accumulated trigger signal sequences into chemical feed requests, each of which requests a quantity of a corresponding chemical. The controller enables the dispensing of chemicals in accordance with the chemical feed requests.