Abstract: A closed granular chemical handling system comprising a dispensing valve and a receiving valve. The dispensing valve and the receiving valve are automatically opened when the valves are coupled together, and are automatically closed when the valves are uncoupled from one another. The valves are configured so that the receiving valve always is the first to open and the last to close. The valves are driven together by a camming structure having a neutral portion that acts as a delay between the opening and closing of both valves so as to allow granular material to flow from between the valves through the receiving valve.