Abstract: A main winch system of a rotary drilling rig includes a main action loop, a pilot control loop, and a feedback control loop. The main action loop includes an engine, a hydraulic pump, a main control valve, a balance valve, a main winch motor, and an oil tank. The pilot control loop includes a pilot handle, a solenoid valve I, a pressure relay, and the main control valve in the main action loop. The feedback control loop includes a solenoid valve II and the hydraulic pump and the main control valve in the main action loop. In response to a lifting action of the pilot handle for the main winch, under the control of a button, the solenoid valve II is energized continuously, and the solenoid valve I is energized and de-energized according to a given rule.

Abstract: A test device for testing and commissioning comprehensive performance of a rotary drilling rig is provided. Dynamometer motors in the test device are provided on a foundation. A torque transmission gearbox is fixed on a gearbox anchoring plate through a gearbox adapter plate. A speed-increasing corner gearbox is provided on the torque transmission gearbox and connected to the dynamometer motors through a transmission shaft, a torque sensor, and a motor coupling sequentially. A drive sleeve is provided in a connecting shaft of the torque transmission gearbox. A lower end of the drive sleeve is connected to a hydraulic loading cylinder through a rotating bearing, a rotating support, and a tension-pressure sensor. The rotating support is fixed in the foundation. The hydraulic loading cylinder is connected to a hydraulic station through a hydraulic pipe. The tension-pressure sensor and a pressure control valve are connected to a computer software control system.

Abstract: A push-pull force control method for a horizontal directional drilling machine with the following steps is provided. According to a correspondence relationship between a motor displacement and a maximum push-pull force of a drilling machine, the motor displacement is first adjusted, so that the required push-pull force can be obtained through the adjustment of the subsequent steps. Then, an oil feeding pressure of the motor is controlled according to a relationship between the push-pull force and the working pressure difference of the motor. Finally, the push-pull force of the motor is controlled in real time according to the oil feeding pressure of the motor to be equal to the required push-pull force value.

Abstract: A double-walled drill pipe includes an outer drill pipe, an inner drill pipe and a drill pipe sealing apparatus. The outer drill pipe includes an axial through hole and a wall surface through hole, and the wall surface through hole is disposed in a wall surface of the outer drill pipe to connect the outside of the double-walled drill pipe and the axial through hole. The inner drill pipe is rotatably disposed in the axial through hole, and includes a fluid guiding hole connected to the wall surface through hole. The drill pipe sealing apparatus is disposed between the outer drill pipe and the inner drill pipe. The drill pipe sealing apparatus is axially located between a driving end and a connecting port of the wall surface through hole connected to the axial through hole. A drilling machine including the double-walled drill pipe is also provided.

Abstract: A push-pull force control method for a horizontal directional drilling machine and a horizontal directional drilling machine are provided. The control method includes: adjusting a working displacement of a motor to enable a maximum push-pull force Fmax corresponding to the working displacement to be greater than a set push-pull force Ft; calculating a working pressure difference ?P of the motor according to the set push-pull force Ft; calculating a working pressure required by the motor according to the working pressure difference ?P and a collected first oil return back pressure of the motor; and adjusting an oil feeding pressure of the motor to enable the oil feeding pressure of the motor to be equal to the working pressure required by the motor. The method accurately and fast controls the push-pull force of the horizontal directional drilling machine.

Abstract: A double-walled drill pipe includes an outer drill pipe, an inner drill pipe and a drill pipe sealing apparatus. The outer drill pipe includes an axial through hole and a wall surface through hole, and the wall surface through hole is disposed in a wall surface of the outer drill pipe to connect the outside of the double-walled drill pipe and the axial through hole. The inner drill pipe is rotatably disposed in the axial through hole, and includes a fluid guiding hole connected to the wall surface through hole. The drill pipe sealing apparatus is disposed between the outer drill pipe and the inner drill pipe. The drill pipe sealing apparatus is axially located between a driving end and a connecting port of the wall surface through hole connected to the axial through hole. A drilling machine including the double-walled drill pipe is also provided.

Abstract: A detachable and combined drive key of a power head of a rotary drilling rig is provided. The drive key includes torque transfer keys and a pressure transfer key. Each torque transfer key is respectively assembled on a key groove on an inner wall of the drive sleeve. The pressure transfer key is assembled at a bottom of a drive sleeve and includes a circular ring structure and a plurality of pressure pads. Each pressure pad has a width less than the torque transfer key. A central surface of each pressure pad is aligned with a central surface of each torque transfer key. The drive sleeve, the torque transfer keys, and the pressure transfer key are combined to form an integrated drive key with a same circular cross-section.