Reasons and Judgment of Drill Pipe Drill Down in Rotary Drilling Rig

Reasons and Judgment of Drill Pipe Drill Down in Rotary Drilling Rig

After the current rotary drilling rig is used for a period of time, when the drill rod is raised or lowered to return the operating handle to the neutral position, the drill rod is not immediately stopped, and it always descends by several tens of centimeters before it stops its movement. As the drilling rod of the rotary drilling rig is slipped down, this article discusses the common reasons for slipping down the drill pipe of the rotary drilling rig and the conventional judgment:

1, the cause of the failure

The drill rod is fixed on the main hoist drum by a wire rope, and the drill rod can be raised or lowered accordingly when the drum is reeled or the wire rope is put. The power of the reels comes from the main winch motor that has been decelerated many times, and its stopping is achieved by a brake directly mounted on the reducer. During the process of raising or lowering the drill pipe, if the operating handle is returned to the neutral position and the drill rod can not be stopped quickly, there are three reasons for this: First, the brake lag; Second, the two hydraulic locks at the end of the motor end Failure, the motor cannot immediately stop the rotation under the effect of the wire rope torque; the third reason is easily overlooked. All drilling rigs have a drill rod release function. This function is provided by the solenoid valve 3 to release the brake signal oil, and then The solenoid valve 2 is connected to the inlet and outlet ports of the main winding motor through two oil pipes so as to ensure that the drill bit can always contact with the working surface and have a certain pressure during the drilling process. In other conditions, the solenoid valve 2 disconnects the two tubings from the inlet and outlet ports of the motor. If the disconnection is not timely, the above-mentioned failure phenomenon will occur.

2, determine the method

(1) Judging solenoid valve 2

Determine whether the solenoid valve 2 is closed tightly: Remove the two oil pipes leading to the solenoid valve 2 at the motor, and plug the two oil ports on the motor end with two plugs. Then, operate the main winch mechanism. If it works normally, it means the fault. The solenoid valve 2 does not close 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 its two cylinders, if it does not work, then remove the lock and conduct a careful inspection. If no reason can be found, a ready-to-use lock can be used as an installation test to find out the cause of the fault. Since the hydraulic lock of the secondary winch is the same as that of the main winch, the lock of the secondary winch can also be borrowed and replaced one by one.