Elevator load control arrangement for a computer-controlled oil drilling rig
AssigneeBJ-Hughes Inc.
InventorsLoren B. Sheldon, James R. Tomashek, Donald H. Ward
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Abstract
A computer-controlled oil drilling derrick is characterized by apparatus for determining the load supported by a traveling block during motion thereof from a first to second position within an oil drilling rig. The apparatus is operative to output a signal functionally related to the net load on the traveling block. Further, the apparatus outputs an appropriately scaled signal functionally related to the load on the traveling block when in a substantially static condition.
Claims9
In an oil drilling rig having a traveling block arrangement, including an elevator, adapted to support a length of drill string as it is lowered into or lifted out of a well bore and having load sensor means for continuously generating an electrical signal representative of the load imposed on the traveling block arrangement, wherein the improvement comprises:
- first sampling means for sampling the signal generated by the sensor at a predetermined time prior to the elevator acquiring a load;
- and,
- comparator means for generating a signal functionally related to the difference between the signal sampled by the first sampling means and the signal generated by the load sensor means and representative of the instantaneous net weight supported by the traveling block arrangement.
Dependencies are inferred from the claim text.