Abstract: The invention provides a method for the removal of contaminating materials from pipework, the contaminating materials comprising deposits on the pipework which cause a reduction in the effective internal diameter of the pipes and thereby effect a reduction in the rate of flow of a fluid through the pipework, the method comprising treating the contaminating materials with at least one carbamate salt. The methods is also suitable for the treatment of contaminating materials which have a particularly deleterious effect on fluid flow and comprise partial or total blockages of the pipework. The carbamate is preferably in the form of an aqueous solution, and a preferred carbamate salt is ammonium carbamate. The treatment may be carried out in the presence of an additive such as caesium carbonate or ammonium bicarbonate. Optionally the treatment may be accompanied by a pre-treatment or post-treatment with aid, this being followed by a water wash.

Abstract: A drill rod changer assembly for a drill rig includes an elongated support shaft having a housing at each end for retaining ends of drill rods, the support shaft being adapted for removable attachment to a drill rig structure, a carousel-type drill rod spacer on the shaft and a pair of gripper arms adapted for removable attachment to a drill rig structure at spaced apart positions adjacent each end of the support shaft. A hydraulic actuation device rotates the support shaft and carousel drill rod spacer between a rod storage position and a rod usage position. Each gripper arm is moved between the drill rod storage and usage positions by hydraulic actuation devices on each arm. Each gripper arm carries a sliding gate member that opens and closes the housings in response to movement of the gripper arm.

Abstract: A fluid powered mechanism has a housing with a generally cylindrical shape and circumferentially adjacent axially extending primary and secondary fluid passageways. Exhaust direction and rotary limit speed are controlled by a flow reversing and regulating ring having a first face with a thru slot and an adjacent blocking flange and a second face having a turning flange which is the reverse of the blocking flange of the first face. The flow reversing and regulating ring is color coded to indicate the size of the fluid flow passageways and, thus, the limit speed provided by the ring. The rotational limit speed and the exhaust direction are determined by selection of the color-coded flow reversing and regulating ring and by its orientation in the tool.