A SEQUENTIAL VALVE HAVING A HOUSING AND A CORROSION-RESISTANT VALVE MEANS RECIPROCALLY MOUNTED THEREIN, SAID VALVE MEANS BEING COOPERABLE WITH THREE SPACED-APART VALVE ELEMENTS IN SIAD HOUSING, SUCH THAT SAID VALVE MEANS MAY BE FORCED INTO OPEN POSITION SEQUENTIALLY WITH RESPECT TO SAID SPACED VALVE ELEMENTS IN ORDER THAT ONE FLUID MAY FLOW AROUND ONE OF SAID VALVE ELEMENTS AFTER ANOTHER FLUID IS SHUT OFF WITH RESPECT TO FLOW AROUND ANOTHER OF SAID VALVE ELEMENTS TO THEREBY PROVIDE FOR PURGING OF SAID VALVE AT THE END OF EACH OPERATING CYCLE THEREOF, AND WHEREIN ONE OF SAID VALVE ELEMENTS IS OPERABLE TO PREVENT THE PURGING FLUID FROM PASSING THROUGH THE VALVE DURING A TIME WHEN PRODUCTS SUCH AS PAINT, OR THE LIKE, ARE BEING DISPENSED THROUGH THE VALVE.