Air closure for storage hopper - has double acting ram which acts on rack displacing butterfly air admission valve

摘要

The closure selectively admits air and allows it to escape for a pulsating chamber of a piston operated hopper (1). It gives cyclic opening and closing of pipework (8) connected to the chamber, under action of a control. The closure is by butterfly valve (9) controlled by a double acting ram following an oscillating movement on its axis. The ram has a piston fixed to a rack, displacement of which controls rotation of the butterfly valve. The ram is fluid supplied by a timer controlled distributor.