Patent attributes
A crust breaker and ore feeder device for electrolytic aluminum smelting employs an in-line three-position pneumatic cylinder capable of moving the plunger shaft to a fully raised position, to a fully lowered position, and to an intermediate, partly lowered position. The full stroke is used for a conventional combined ore dispensing and a crust breaking operation; a partial stroke between the fully raised position and the intermediate position permits ore dispensing without a crust breaking; and a partial stroke between the intermediate position and the fully lowered position permits crust breaking operation without ore feeding. The cylinder can take form of a tandem cylinder having upper and lower axially aligned cylinder portions, with rods not connected to one another.
