Air or Gas Circulation Bits
A third type of circulation medium is compressed air or gas, and can be
used with either regular or jet circulation bits. Bits manufactured for air or
gas circulation have special passageways from the bore of the bit to the
bearings, through which a portion of the air or gas is diverted to keep the
bearings cool and purged of dust or cuttings. From the special passageways
to the bearings, the air or gas passes through a number of strategically
located ports or holes in the bearing journal, flows through the bearing
structure and exhausts at the shirttail and gauge of the bit, to flow up the
annulus.
A third type of circulation medium is compressed air or gas, and can be
used with either regular or jet circulation bits. Bits manufactured for air or
gas circulation have special passageways from the bore of the bit to the
bearings, through which a portion of the air or gas is diverted to keep the
bearings cool and purged of dust or cuttings. From the special passageways
to the bearings, the air or gas passes through a number of strategically
located ports or holes in the bearing journal, flows through the bearing
structure and exhausts at the shirttail and gauge of the bit, to flow up the
annulus.
