Closed loop control system for diamond core drilling
AssigneeBoart Longyear Company
InventorsLouis E. Silay, Raymond B. McKinley
Life of this patent
Estimating the term…
Abstract
A closed loop control system for a core drilling mechanism automatically controls the penetration rate, the weight on the drill bit, and the torque load applied to the drill string, and maintains all three at or below preselected maximum values. The closed loop control system incorporates a controller that receives sensed information and generates corresponding control signals to control the penetration rate and thus the weight on the drill bit and the torque load through a servo valve in a hydraulic drive circuit. One or more sensors are provided to sense the penetration rate of the drill bit, and are coupled with the controller. Similarly, sensors are provided to determine the weight on the drill bit and the torque load applied to the drill string.
Claims10
A control system for controlling operation of a core drilling device, the core drilling device including a drive system to advance and retract a drill string carrying a drill bit, the control system comprising:
- a first sensor in communication with the core drilling device, the first sensor being operative to sense a weight on the drill bit during a pull-down mode of operation, and to generate a corresponding first signal;
- a second sensor in communication with the core drilling device, the second sensor being operative to sense the weight on the drill bit during a hold-back mode of operation, and to generate a corresponding second signal;
- and
- a controller in electrical communication with the respective sensors and with the drive system, the controller being programmed with a preselected maximum value for the weight on the drill bit, wherein the controller is responsive to one of the signals having a value above the respective maximum value to control the drive system to reduce the rate of penetration of the drill bit.
A method of controlling weight on a drill bit, the drill bit being carried by a drill string and driven by a drilling device, the method comprising:
- providing first and second sensors for sensing the weight on the drill bit, wherein the first sensor is operative to sense the weight on bit during a pull-down mode of operation and to generate a corresponding first signal, and wherein the second sensor is operative to sense the weight on bit during a hold-back mode of operation and to generate a corresponding second signal;
- monitoring the first sensor during the pull-down mode;
- monitoring the second sensor during the hold-back mode;
- determining whether the sensed weight on bit exceeds a preselected maximum value for the weight on the drill bit;
- and
- reducing the rate of penetration of the drill string if the sensed weight exceeds the preselected maximum value.
Dependencies are inferred from the claim text.