Control apparatus for exhaust gas recirculating system

Claim 1

Control apparatus for a vacuum operated device comprising, a housing having a tubular section and first and second end covers substantially closing opposite ends of said section, a wall structure extending transversely of said tubular section and intermediate the ends thereof, said wall structure having a first recess, the open side of which faces said first end cover, a vacuum control valve means including a first flexible diaphragm extending transversely of said first recess, means forming a valve port in the closed end of said first recess, a valve member movable by deflections of said diaphragm and adapted to open and close said port, a second diaphragm extending transversely of said tubular section adjacent said first end cover and facing said first diaphragm, said second diaphragm cooperating with said first end cover to form a first vacuum chamber, means mechanically interconnecting said diaphragms, a second recess in said wall section and having the open side facing said second end cover, a third diaphragm extending transversely of said second recess and cooperating with the walls of said second recess to form a second vacuum chamber, a valve plate extending across said second recess and cooperating with said third diaphragm to form a third vacuum chamber, said valve plate and said second end cover cooperating to form a vacuum area, means carried by said valve plate forming a check valve to admit fluid from said vacuum area into said third vacuum chamber, means forming a valve port through said plate, a valve closure member operatively connected with said third diaphragm and adapted to open and close on the last mentioned valve port, and means forming a vacuum reservoir comPrising substantial portions of said tubular section, said wall structure and said second end cover and including said vacuum area.