Passive liquefier batch transition process

摘要

A method and apparatus for blending consecutive batches of photographic emulsions which includes two modified passive liquefaction apparatus, each capable of independent batch melt production. Each modified liquefaction apparatus has a metering pump associated therewith to draw melt therefrom and deliver the melt to a surge pot from which the melt can be pumped to the coating operation. Each metering pump is flow controlled and the discharge lines combined to allow for static in-line mixing of the two metering pump discharges. A control system allows for regulated flow from each of the metering pumps such that the transition of drawing from the first liquefaction apparatus to the second liquefaction apparatus occurs well in advance of the exhaustion of the melt in the liquefaction apparatus. During the transition period, total flow from the first liquefaction apparatus is constantly decreased and total flow from the second liquefaction apparatus is constantly increased with total flow from the two liquefaction apparatus remaining the same. In such manner, when melt in the first liquefaction apparatus is exhausted, 100% of the flow is coming from the second liquefaction apparatus thereby providing for a smooth transition with little variation in the sensitometric parameters of the melt.