AUTOMATIC CONTROL FOR ROTARY DRILL

• US 3,613,805 A
• Filed: 09/03/1969
• Issued: 10/19/1971
• Est. Priority Date: 09/03/1969
• Status: Expired due to Term

• Current Assignee: Becor Western, Inc. (Caterpillar Incorporated)
• Original Assignee: Jon R. Lindstad, Thomas A. Stoner
• Inventors: Stoner, Thomas A., Lindstad, Jon R.
• Primary Examiner(s): Novosad, Stephen J.
• Application Number:
  US04/854,963
• Time in Patent Office: 776 Days
• Field of Search: 175/27,38,51,48,114,113,122,162 166/250,53,64 73/151,151.5 173/2,4,22
• US Class Current: 340/853.6
• CPC Class Codes: E21B 21/08 Controlling or monitoring pressure or flow of drilling fluid, e.g. automatic filling of boreholes, automatic control of bottom pressure valve arrangements therefor E21B21/10
• CPC Class Codes: E21B 44/00 Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions

Abstract

An automatic blasthole drill, in addition to rotary and downfeed speed controls, has an automatic depth control to effect collaring and automatic hoist when desired depth is reached, an automatic water injection system responsive to the depth control and air pressure devices to control the amount and turnoff of water injection, and air-pressure-responsive protective devices to vary water injection and to trigger automatic shut down. The circuits and devices for effecting the mentioned controls are disclosed in detail. A copending application incorporated by reference discloses a downfeed speed and force control responsive to rotary torque.

Claims

1. A rotary earth-boring drill having a drill mounted for rotary and axial feed motion, a controlled rotary drive motor connected to rotate said drill, and a controlled downfeed drive motor connected to axially downfeed and hoist said drill, in combination therewith, a depth counter system having a pulse-generating member connected to be driven by said downfeed drive motor to generate a pulse signal for each increment of downfeed movement, and an adjustable counter connected to receive said pulses and to register said pulses and to energize a relay when a preset number of pulses have been generated;

and a downfeed drive control connected to cause said downfeed drive motor to hoist said drill when said relay is energized.

2. A rotary earth-boring drill as set forth in claim 1, wherein said depth counter system has a second adjustable counter connected to receive and register said pulses and to actuate a switch when a preset number of pulses have been generated;

and a rotary speed control connected to control the speed of said rotary drive motor and responsive to said switch to accelerate said motor to a preset speed when said switch is actuated.

3. An automatic control system for a rotary drill comprising the combination of a rotary drill mounted for rotary and axial downfeed movements;

a rotary drive motor connected to said rotary drill to rotate said rotary drill and responsive to a rotary speed control means to operate at preset speeds responsive To a collaring depth command signal;

a downfeed drive motor connected to said rotary drill to impart axial downfeed and hoist movements to said rotary drill and responsive to a downfeed speed control means to operate at preset speeds responsive to a pressure command signal and to a total depth command signal; and

a depth counter connected to said downfeed drive motor to sense distance of downfeed movement of said rotary drill and to generate said collaring depth command signal to said rotary speed control at a preset depth and to generate said total depth command signal to said downfeed speed control at another preset depth.

4. An automatic control system for a rotary blasthole drill as set forth in claim 3, wherein said rotary drill is hollow and an air compressor is connected to the top end of said vertical hollow rotary drill and forces air through and out the bottom end of said hollow rotary drill;

and an air pressure sensor is connected to measure the air pressure in said hollow rotary drill and generate an electrical air pressure signal proportional to said air pressure;

an air pressure monitor connected to receive said air pressure signal and generate a command signal to said downfeed speed control slowing down or reversing the direction of downfeed of said rotary blasthole drill responsive to said air pressure signal.

5. An automatic control for a rotary blasthole drill comprising the combination of a hollow rotary drill mounted for rotary movement and axial movement;

a rotary drive motor connected to said rotary drill to rotate said rotary drill;

a rotary speed control means connected to operate said rotary drive motor at a preset speed and to alter said preset speed responsive to a collaring command signal;

a downfeed drive motor connected to said rotary drill to impart downfeed and hoist movements to said rotary drill;

a downfeed speed control connected to operate said downfeed drive motor at a preset speed and to alter said preset speed responsive to said collaring command signal and to a pressure command signal and to a total depth command signal;

an air compressor connected to the top end of said hollow rotary drill to force air through and out the bottom end of said hollow rotary drill;

a water injection system connected to force water into said air being forced through said hollow rotary drill and to shut off said water responsive to a water command signal;

an air pressure sensor connected to measure the air pressure in said hollow rotary drill and to generate an electrical air pressure signal proportional to said air pressure;

an air pressure monitor connected to receive said air pressure signal and to generate a pressure command signal to said downfeed speed control slowing down or reversing the direction of axial movement of said rotary drill when said air pressure exceeds a preset amount and to generate a water command signal to said water injection system shutting off said water when said air pressure signal exceeds another preset amount;

a collaring depth counter connected to said downfeed drive motor to sense the amount of downfeed movement of said rotary drill and to generate a collaring command signal to said downfeed speed control and said rotary speed control reducing said preset linear and rotary speeds of said rotary blasthole drill until said rotary drill travels a preset linear distance into the earth;

a total depth counter connected to said downfeed drive motor to sense the amount of linear movement of said rotary drill and to generate a total depth command signal to said downfeed speed control to hoist said rotary drill when said rotary drill travels a preset linear distance into the earth; and

a wet depth counter connected to said downfeed drive motor to sense the amount of linear movement of said rotary blasthole drill and to generate a water command signal to said water injection system turning off the water when said rotary blasthole drill travels a preset linear distance into the earth.

6. An automatic control system for a blasthole drill as set forth in claim 5, wherein said water injection system comprises the combination of a water pump connected to a source of water and connected to pump said water through an exhaust line when the pump is rotated;

a motor connected to rotate said water pump;

a plurality of flow control valves connected in a parallel configuration to said exhaust line;

a common outlet line connecting the exhaust ports of said flow control valves with said air flowing into said hollow rotary blasthole drill;

a selector switch connected to open a preset flow control valve or combination of flow control valves until said water command signal is received and when said water command signal is received and removed a different flow control valve or combination of flow control valves is opened allowing less water to flow than said preset flow control valve or combination of flow control valves.

7. An automatic control for a rotary blasthole drill as set forth in claim 5, wherein means driven by said downfeed drive motor sequentially energizes a plurality of relays during downfeed and hoist;

said relays are connected to sequentially deenergize during downfeed and to hold during hoist; and

said relays have contacts connected to command said downfeed speed control to retract said drill when more than one of said relays is simultaneously held energized.