Definition - What does Percussion Hammer mean?
The percussion hammer is a part of the down-the-hole (DTH) equipment and is attached to the end of a drill string.
A percussion hammer is mainly used for drilling boreholes in hard rock. The DTH system requires a minimal amount of rotational torque to cut rock that also allows the hammer to drill straight. Vibrations from the DTH percussive hammer can stimulate the formation to enhance production capability, reducing the need for hydraulic fracturing.
Trenchlesspedia explains Percussion Hammer
The percussion hammer is driven by compressed air that is directed to the hammer via the rotation spindle and drill pipes. The exhaust air from the action of the hammer is discharged through holes in the drill bit which also cleans the drilled hole.
Rotation and feed force is transmitted to the percussion hammer via the drill pipes from a rotation unit. Rotation to the drill bit is imparted from the splined union between the driver chuck which is threaded to the front end of the casing, and the drill bit.
The feed force to the drill bit is transmitted from the front end of the driver chuck, and the axial movement of the drill bit is limited by the split stop ring. Water is prevented from entering the hammer through the drill bit using a check valve during the period when the compressed air supply is shut off.
Once the compressed air has imparted its pressure energy to the piston, it comes out as exhaust through air channels on the splines of the drill bit and chuck.