IMMERSION AIR HAMMER Russian patent published in 2007 - IPC E21B4/14 

FIELD: mining and construction, particularly down-hole impacting means, namely fluid operated immersion hammers for well drilling in rock having average and high strength.

SUBSTANCE: immersion air hammer comprises body, stepped striker having turning in stem center, idle stroke chamber and working stroke chamber, supply and discharge channels and drilling tool. Working stroke chamber includes annular controllable chamber and end constant-pressure chamber. Stepped shell enclosing striker is installed in the body so that supply and discharge channels extend in longitudinal direction and annular cavity is created in-between. Longitudinal channel extending through annular cavity is created in shell. The longitudinal channel is permanently opened in idle chamber and has radial outlet facing inner shell surface to provide periodic opening thereof in end constant-pressure chamber with striker stem end edge.

EFFECT: increased impact power due to intensive idle stroke of striker and improved economical efficiency due to possibility of total exhaust air usage for well bottom cleaning without additional air intake and increased hammer service life due to isolation of hammer interior from annular space medium carrying abrasive dust.

1 dwg