HIGH FREQUENCY PERCUSSION HAMMER Russian patent published in 2018 - IPC E21B4/14 

FIELD: drilling.

SUBSTANCE: invention relates to the field of drilling, specifically to a hydraulic percussion device. Fluid pressure driven, high frequency percussion hammer comprises housing (8, 9, 10) which in one end thereof is provided with drill bit (11), designed to act directly on the hard formation, which percussion hammer further comprises hammer piston (20), movably received in said housing (8, 9, 10) and acts on drill bit (11). Hammer piston (20) has longitudinally extending bore (41) having predetermined flow capacity and closeable in the upstream direction by valve plug (23) that follows hammer piston (20) during its stroke until the plug is mechanically stopped, which valve plug (23) is controlled by an associated valve stem slidably received in a valve stem sleeve, said valve stem comprises stopping means (50), able to stop valve plug (23) and promptly returns plug (23) by a predetermined percentage of the full stroke length of hammer piston (20) and separates valve plug (23) from seat seal on hammer piston (20), such that said bore thus being opened and allows bore fluid to flow freely through the bore, such that hammer piston (20) can recoil by little resistance. Stopping means (50) includes magnet (58), which magnet cooperates with the valve stem in order to be able to retain the valve stem and thus the valve plug (23) during predetermined conditions.

EFFECT: providing high impact frequency and efficiency of the device.

11 cl, 32 dwg