Seal protecting method for use with spiral-flow barrel finishing machine

Abstract

Any part of an abrasive media in a solid particle or liquid form is prevented from entering a seal and/or the area where a rotary shaft bearing for a rotating barrel is sealed, thereby protecting the bearing and/or its seal against any possible damage that may be caused by abrasive media. A the barrel finishing operation performed by rotating a rotating barrel rotatably mounted inside a cylindrical stationary barrel on a lower portion thereof in a spaced relationship to the stationary barrel. The stationary barrel has an outer bottom plate at the bottom end thereof. At least one blade is mounted on the back side of a rotating plate forming the bottom end of the rotating barrel, and is rotated by rotating the rotating plate to any part of the abrasive media existing between the back side of the rotating plate and the top side of the outer bottom plate in the direction remote from the rotary shaft, thereby developing a negative pressure or vacuum area located on the back side of the rotating plate and on the side of the blade nearer to the rotary shaft. Air is then drawn from the atmosphere into the vacuum area by the action of the negative pressure, and thus an air layer is created in the vacuum area. The air layer prevents that part of the abrasive media from entering the rotary shaft bearing and/or its seal.