Reasons and judgments of the drill pipe slipping during the use of engineering drilling rig

1, the cause of the failure

    The drill pipe is fixed on the main hoisting reel by a wire rope, and the drill pipe can be raised or lowered correspondingly when the reel is wound or the wire rope is placed. The power of the reel comes from the main hoisting motor that has been decelerated several times. Its stopping is achieved by the brake directly mounted on the reducer. During the lifting or lowering of the drill pipe, if the operating handle is returned to the neutral position and the drill pipe cannot be stopped quickly, there may be three reasons: one is the brake lag; the other is the two hydraulic locks at the motor end outlet. Failure, the motor can not stop rotating immediately under the action of the wire rope torque; the third reason is easily overlooked, all the engineering rigs have a drill rod release function, which is provided by the solenoid valve 3 to release the brake signal oil, Then,   the solenoid valve 2 is connected to the inlet and outlet ports of the main hoisting motor through two oil pipes, thereby ensuring that the drill bit can always contact the working surface and have a certain pressure during the drilling process. In other working conditions, the solenoid valve 2 disconnects the two oil pipes leading to the motor inlet and outlet ports, and if the disconnection is not timely, the above-mentioned failure phenomenon will occur.

    2, the method of judgment

    (1) Judging the solenoid valve 2

    Judging whether the solenoid valve 2 is closed tightly: remove the two oil pipes leading to the solenoid valve 2 at the motor, and block the two oil ports of the motor end with two plugs respectively, and then operate the main hoisting mechanism. If it works normally, it indicates the fault. The solenoid valve 2 is not closed tightly; if it is still abnormal, its components must be inspected.

    (2) Judging the hydraulic lock

    Determine whether there is a problem with the hydraulic lock: First adjust the two lock cylinders. If it does not work, remove the lock and check it carefully. If the reason is not found, you can use the ready-made lock to do the installation test to find out the cause of the fault. Because the hydraulic lock of the auxiliary hoist is the same as that of the main hoist, it is also possible to borrow the lock of the auxiliary hoist and use the method of replacing one by one to identify the quality of the main hoist lock. If there are no problems with both locks, check the next step.

    (3) Judging the brake signal oil

    Check the speed of the brake signal oil supply and disconnection: the current engineering rig, the flow rate of the signal oil can be adjusted, that is, the time of the main hoist release brake can be adjusted. Therefore, for both types of drilling rigs, the flow of the signal oil can be adjusted by its regulating valve.   If the working condition of the machine is still abnormal, it is necessary to check whether the oil pipe of the brake signal oil is blocked. If these inspection sites are normal, you can only continue to check.

    (4) Judging the brake

Dismantle the brake: See if the brake piston moves smoothly in the working line, and repair or replace it for the cause of the malfunction.