A drill string section of a drill string for drilling in the ground having arranged on the outside of the drill string section at least one marking by means of which abrasion can be recognized.

A down the hole rock drilling machine and a method of drilling rock. The drilling machine includes a reciprocating piston, which has a sleeve-like configuration. Inside a central opening of the piston is arranged one or more fluid passages for conveying pressurized fluid during the work cycle of an impact device of the drill machine.

A down the hole rock drilling machine and a method of drilling rock. The drilling machine includes a reciprocating piston, which has a sleeve-like configuration. Inside a central opening of the piston is arranged one or more fluid passages for conveying pressurized fluid during the work cycle of an impact device of the drill machine.

The invention relates to a rotary drilling tool and to a method for producing a borehole in the ground, having a base body, a removal device which has at least one hammer unit which comprises a hammer element driven in axially reversing manner, and a discharge line for discharging removed ground material and drilling suspension. According to the invention it is provided that a pumping device is arranged on the base body along the discharge line, and that the pumping device is configured for pumping off the removed ground material with drilling suspension through the discharge line.

The invention relates to a rotary drilling tool and to a method for producing a borehole in the ground, having a base body, a removal device which has at least one hammer unit which comprises a hammer element driven in axially reversing manner, and a discharge line for discharging removed ground material and drilling suspension. According to the invention it is provided that a pumping device is arranged on the base body along the discharge line, and that the pumping device is configured for pumping off the removed ground material with drilling suspension through the discharge line.

A system and method of fabricating a percussion tool that includes one or more surfaces modified using the ferritic nitrocarburization process. The percussion tool includes a piston positioned in sliding contact within a casing. The piston includes an inner wall and an outer wall, where the inner wall defines a passageway extending longitudinally therethrough. The outer wall is positioned in close fitting relationship with an internal surface of the casing. One or more surfaces of at least one of the casing's internal surface and/or the piston's outer wall are modified using the ferritic nitrocarburization process.

A system and method of fabricating a percussion tool that includes one or more surfaces modified using the ferritic nitrocarburization process. The percussion tool includes a piston positioned in sliding contact within a casing. The piston includes an inner wall and an outer wall, where the inner wall defines a passageway extending longitudinally therethrough. The outer wall is positioned in close fitting relationship with an internal surface of the casing. One or more surfaces of at least one of the casing's internal surface and/or the piston's outer wall are modified using the ferritic nitrocarburization process.

A directional drilling apparatus using a water hammer unit according to the present invention includes a hammer body in which a bit unit configured to perform boring work is installed to be movable upward and downward at an end portion of the hammer body, a piston slidably installed on the hammer body and including an operating fluid discharge part formed in a longitudinal direction, a drive unit installed between the hammer body and the piston to support an upper portion of the piston and configured to move the piston upward and downward using water supplied through a rod connected to the hammer body, a hammer unit including a rotary shaft coupled to a bit by a first coupling part so as to transmit a rotational force in a state in which the hammer unit passes through the piston installed on the hammer body and is moved upward or downward by the bit, and a mud motor unit coupled to the hammer body and configured to rotate the rotary shaft.

A multi-fluid drilling system 10 drilling is disclosed for drilling a hole or well 11. The system 10 is coupled to a dual wall drill string 12. The drill string 12 is configured to enable separate flow of a first fluid 14 and a second fluid 16. The system 10 has a hammer 22 and a downhole motor 24. Both the hammer 22 and the motor 24 are supported by and are coupled to the drill string 12. The motor 24 is uphole of the hammer 22. The hammer 22 is arranged so that when supported by the drill string 12 the first fluid 14 when flowing through the drill string 12 is able to flow to and power the hammer 22. As the motor 24 is disposed between the hammer 22 and the drill string 12 the first fluid 14 is also able to flow through the motor 24. To this end the motor 24 has a channel 25 to enable the first fluid to flow from the drill sting 12 to the hammer 22. The channel 25 acts as a part of a flow path or conduit for the first fluid 14.

A multi-fluid drilling system 10 drilling is disclosed for drilling a hole or well 11. The system 10 is coupled to a dual wall drill string 12. The drill string 12 is configured to enable separate flow of a first fluid 14 and a second fluid 16. The system 10 has a hammer 22 and a downhole motor 24. Both the hammer 22 and the motor 24 are supported by and are coupled to the drill string 12. The motor 24 is uphole of the hammer 22. The hammer 22 is arranged so that when supported by the drill string 12 the first fluid 14 when flowing through the drill string 12 is able to flow to and power the hammer 22. As the motor 24 is disposed between the hammer 22 and the drill string 12 the first fluid 14 is also able to flow through the motor 24. To this end the motor 24 has a channel 25 to enable the first fluid to flow from the drill sting 12 to the hammer 22. The channel 25 acts as a part of a flow path or conduit for the first fluid 14.