Apparatus of the renewal of the solutions of automatic processing of photographic films

摘要

An automatic replenishing system for maintaining the chemical concentration of the liquid in a film processing tank, which automatically energizes a replenishing pump at regular timed intervals (e. g. every 30 seconds) regardless of whether or not the control circuitry indicates a need for replenishment, and which includes an element for sensing the density and velocity of the film and for producing a combined signal which controls the running time of the pump after each energization. The replenishing system also includes a second replenishing pump for maintaining the condition of the liquid in the processing tank, which second pump is energized automatically after a predetermined number of said regular timed intervals, or after a predetermined number of said regular timed intervals in which a zero film density or non-use condition has been detected for a preset running time.