concentrator

1. One who concentrates.

2. A hub.

3. An apparatus for the separation of dry comminuted ore, by exposing it to intermittent puffs of air.

4. A frame or ring of wire or hard paper fitting into the cartridge case used in some shotguns, and holding the shot together when discharged, to secure close shooting; also, a device for slightly narrowing the bore at the muzzle for the same purpose.

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