Liquid dispensing system and automatic selector therefor

摘要

A dispensing system comprising first and second collapsible storage containers, a pump and a pressure responsive selector coupled to both of the storage containers and to the intake side of the pump. The selector includes a valve movable between a first position in which the selector provides communication between the first storage container and the pump and blocks communication between the second storage container and the pump and a second position in which the selector provides communication between the second collapsible container and the pump and blocks communication between the first collapsible container and the pump. An actuator is responsive to the pressure drop at the selector resulting from the collapse of one of the collapsible containers for moving the valve from one of its positions to the other of its positions.