The Research On Invariable Drilling Pressure Servo Control System Of Electric Drive Drilling Rig

In this article, it researched and made an experiment on the rising control system of theelectrical drive rigs, and through the PLC to control the drawworks and the hydro-discservo-brake, keeps the pressure between the drilling bit and the rock constant to realize theinitiative and drilling in invariable drilling pressure.When the drill bit in the bottom of the well, set the drilling pressure, launch theinvariable drilling pressure drilling model. The signal of the deadline tension keeps ininitiative, in the condition of no external interference, PLC control the three position four-waydirectional control valve in the middle position, the piston rod of the hydraulic cylinder doesnot make the stretching, the drilling bit does not change the position, and the pressure keepinvariable;When the drilling tubular move upward, because of the external interference, thepressure between drilling bit and rock become lower, the tension of deadline become bigger,the sensor test the pressure signal and sent it to the controller, compare with the settingpressure, the deviation through the control adjustor to sent the order to the three positionfour-way directional control valve and the motor, the valve in the left position, the motor drivethe throttle valve adjust the knob to change the mouth size to control the flow rate of thehydraulic oil into the no rod chamber, the hydraulic oil of the rod chamber flow out of thecylinder back to the oil tank. So the rod extend to make the drilling bit in the same position,the pressure will keep invariable.When the drilling tubular move downward, because of the external interference, thepressure between drilling bit and rock become higher, the tension of deadline become smaller,the sensor test the pressure signal and sent it to the controller, compare with the settingpressure, the deviation through the control adjustor to sent the order to the three positionfour-way directional control valve and the motor, the valve in the right position, the motordrive the throttle valve adjust the knob to change the mouth size to control the flow rate of thehydraulic oil out of the no rod chamber back to the oil tank, the hydraulic oil of the rodchamber flow into the cylinder. So the rod shrink to make the drilling bit in the same position,the pressure will keep invariable.