Reverse circulation down-the-hole hammer

When percussion or hammer drilling the percussion mechanism is called a DTH or down the hole hammer. This drilling tool is located directly above the down hole hammer bit. The driller transfers weight to the bit through the drill pipe as well as provides some rotation. Through the use of a compressor, the pressurized air is forced to the down hole hammer. As the drilled hole gets deeper the driller adds more drill pipe to the string. The piston strikes the impact zone of the hammer bit; hammers are always used as part of a casing advancement system and can be used in reverse circulation applications. DTH hammers are common when drilling blast holes and water wells.