Importance

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Abstract

A derrick is provided with a vertically movable elevator for suspending a string of elongated well elements, such as pipes. An immovable lower support is provided for suspending the string, and an automatic tong is provided for screwing and unscrewing pipes to and from the string. A manipulator grips and delivers a pipe to an operating position in axial alignment with the well bore. A control system includes position sensors for sensing the positions of a well pipe, one of which sensors is mounted on the elevator, a second sensor is mounted on the automatic tong, and a third sensor is mounted on the manipulator. The control system also includes a programmed logical control unit, through which the sensors are connected to a drive system. The first sensor is connected to a drive for vertically moving the elevator, a drive for closing and opening grippers on the elevator, and a drive adapted to transversely move the automatic tong. The second sensor is connected through the control unit to a drive for vertically moving the elevator, and the third sensor is connected to a drive for longitudinally moving the grippers of the manipulator.

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First Claim