The hydraulic system is the muscle of the crawler mounted drill rig, and its control is a vital part of the overall control system. Hydraulic valves are used to direct the flow of hydraulic fluid to different actuators, such as cylinders and motors.
[pdf] An enlarged pipe at the top of a casing string that serves as a funnel to guide drilling tools into the top of a well. The bell nipple is usually fitted with a side outlet to permit drilling fluids to flow back to the surface mud treating equipment through another inclined pipe called a flowline.
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