A compactor for compacting fluid-laden incompressible metal chips and shavings comprising, in combination:
- a compaction chamber forming an enclosing wall, an opening to the chamber through which the metal chips and shavings are introduced, the chamber having a first end adjacent which metal pellets are formed from the metal chips and shavings;
- a first piston closing a second end of the chamber opposite the first end;
- a barrier adjacent the first end of the chamber, the barrier being movable between a first position at which the barrier blocks the first end to prevent metal pellets in the chamber from being discharged through the first end and a second position at which the barrier permits metal pellets to be discharged, the barrier being so disposed and arranged with respect to the enclosing wall of the chamber to permit fluid to be expelled from the chamber between the barrier and the enclosing wall when the barrier is in its first position;
- first drive means for moving the first piston between positions relative to a second end of the chamber, the first drive means comprising a hydraulic cylinder containing a second piston connected to the first piston, the second piston being operated by hydraulic pressure, a hydraulic circuit connected to the cylinder to operate the second piston, the hydraulic circuit including a hydraulic conduit connected to a source of low pressure, and connection means selectively connecting a source of high pressure to the conduit, the second piston being responsive to the source of low pressure to move the first piston between a first position in which the first piston permits the metal chips and shavings to enter the chamber through the opening between the first piston and the first end;
- and
- a second position in which the first piston blocks the opening and imparts a first compacting pressure on the metal chips and shavings in the chamber when the barrier is in its first position, the first compacting pressure being of such magnitude as to expel fluid from the metal chips and shavings and from the chamber and to form a loosely compacted pellet from the metal chips and shavings in the chamber, the loosely compacted pellet having substantial interstices therein;
- and
- the second piston being responsive to the source of high pressure to operate the first piston to move between its second position and a third position in which the first piston imparts a second compacting pressure on the loosely compacted pellet in the chamber when the barrier is in its first position, the second compacting pressure being greater than the first compacting pressure and being of such magnitude as to expel fluid from the loosely compacted pellet and from the chamber to form a compact metal pellet from the loosely compacted pellet substantially devoid of fluid and interstices,
- the second piston being further responsive to the source of low pressure to move the first piston to a fourth position when the barrier is in its second position to discharge the compact metal pellet from the chamber;
- second drive means for operating the barrier between its first and second positions;
- and
- feed means for feeding metal chips and shavings through the opening in the chamber when the first piston is in its first position.