US Patent 7143773 Intermittent pressure module for a vacuum regulator

An intermittent pressure module for controlling the position of a valve between two positions comprising diaphragm means; a plurality of ports associated with said diaphragm means for exposing said diaphragm means to a selected pressure in said first position, and ambient pressure in said second position; swing means associated with said diaphragm means and said valve means for intermittently displacing said valve means when said diaphragm means is exposed to said selected pressure in said first position and ambient pressure in said second position.