Automatic developing system for photographic paper - has stepped distribution valve connecting compressed air to various processing liq. containers to force selected liq. into bath

摘要

Several containers are provided for different processing liquids. Each container is connected to a gas line (57) conveying gas under pressure to the container. The gas drives the liq. up through an outlet line (56) into a collection line. A distribution valve (70) determines which liq. passes to the collection line. This valve is located in the has lines and not in the liq. lines leading from the containers to the developer vessel. A sensor detects the flow of liq. and actuates a timer that moves the distribution valve on after a given time has elapsed. The distribution valve's input is connected to the source of compressed gas, e.g. an air pump, and its outputs are connected to the gas lines leading to the containers. The sensor is located in the collection line. The distribution valve is driven by a stepping motor (72). A two-way valve is located between the distribution valve and the pressure source and connects the valve either to that pressure source or a suction source. Suction is applied to the gas lines at the end of each step. The suction pump is the opposite end of the pressure pump.