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The transmission system of an oil drilling rig is a device that transfers the energy from the power source to various working machines, enabling the hoisting, rotation, circulation and other systems of the drilling rig to work in coordination. The following is a detailed introduction to its composition and characteristics: Ⅰ. Components Gearbox: It is used to reduce the rotational speed and increase the torque to meet the rotational speed and torque requirements of different working machines. For example, the drawworks requires a large torque to hoist and lower the drilling tools. Through the gearbox, the high rotational speed and low torque of the power source can be converted into the low rotational speed and high torque required by the drawworks. Clutch: It is a component in the transmission system used to connect and cut off the power transmission. It allows the working machine to engage with the power source when needed to obtain power for operation, and can also cut off the power when not needed to achieve the independent operation or stop of the working machine. Common types include jaw clutches and friction clutches. Coupling: It is used to connect the shafts of different components, transmit torque and rotational motion, and at the same time compensate for the installation errors and relative displacements between the shafts. For example, when connecting the shafts of the power source and the gearbox, and the gearbox and the working machine, the coupling can ensure the effective transmission of power and adapt to the slight deformation and displacement of the shafts during the operation of the equipment. Drive shaft: It is an important component for power transmission, usually made of high-strength steel, and is used to transmit torque and rotational motion between different components. The drive shaft needs to have sufficient strength and stiffness to withstand the huge torque and bending moment during the transmission process. Chain and sprocket for workover rig: In the transmission system of some oil drilling rigs, chains and sprockets are used to transmit power. The chain is put on the sprocket, and the rotation of the sprocket drives the chain to move, thus transmitting power from one component to another. Chain drive has the advantages of high transmission efficiency and can adapt to a relatively large center distance. Belt drive device: Generally composed of banded V belts and pulleys, it transmits power through the frictional force between the belt and the pulleys. Belt drive has the characteristics of smooth transmission, buffering and vibration absorption, and overload protection. It is often used in parts where the requirements for transmission accuracy are not high and a certain degree of flexible transmission is needed. Ⅱ. Transmission ModesIn actual oil drilling rigs, a composite transmission system that combines multiple transmission modes is usually adopted according to factors such as the type of the drilling rig, working conditions, and performance requirements, so as to give full play to the advantages of various transmission modes and meet the complex requirements of oil drilling operations. Mechanical Transmission System Composition and Functions of Components Gear transmission: Composed of meshing gears, it transmits power and motion through the meshing of the teeth of the gears. It can achieve a large transmission ratio, has high transmission efficiency, a compact structure, and reliable operation. It is often used in components such as gearboxes and transfer cases to meet the rotational speed and torque requirements of different working machines. Chain transmission: Composed of a chain and sprockets, the chain is put on the sprockets, and the rotation of the sprockets drives the chain to move, thereby transmitting power to other components. It is suitable for the transmission between two shafts with a relatively large center distance, can adapt to harsh working environments, and has a relatively high transmission efficiency. For example, the winch drive part of the drilling rig may use chain transmission. Belt drive: Generally composed of a belt and pulleys, it relies on the frictional force between the belt and the pulleys to transmit power. It has the advantages of smooth transmission, buffering and vibration absorption, and the belt will slip on the pulley to play a protective role when overloaded. It is often used in the transmission of auxiliary equipment of the drilling rig where the requirements for transmission accuracy are not high and a certain degree of flexible transmission is needed. Characteristics: The mechanical transmission system has high transmission efficiency, reliable operation, can transmit large torque and power, has a relatively simple structure, and low maintenance cost. However, the transmission ratio is fixed, the flexibility is poor, there are many components, and the requirements for installation and debugging are relatively high. Hydraulic Transmission System Composition and Functions of Components Torque converter: It is the core component of the hydraulic transmission system, mainly composed of a centrifugal pump impeller, a turbine, and a guide wheel. The pump impeller is connected to the power source and converts mechanical energy into the kinetic energy of the liquid; the turbine is connected to the working machine and converts the kinetic energy of the liquid into mechanical energy for output; the guide wheel plays the role of changing the flow direction of the liquid and increasing the torque. The torque converter can automatically change the output torque and rotational speed under different working conditions, enabling the drilling rig to have good adaptability. Hydraulic pump: It converts mechanical energy into hydraulic energy, provides high-pressure oil for the hydraulic transmission system, and drives the execution components such as the torque converter and the hydraulic motor to work. Hydraulic motor: It converts hydraulic energy into mechanical energy and is used to drive the working machines of the drilling rig, such as the drawworks and the oil drilling rotary table. The hydraulic motor has good speed regulation performance and a large torque output capacity. Characteristics: The hydraulic transmission system has good overload protection performance. When the working machine encounters an overload, the torque converter will automatically slip to protect the equipment from damage. At the same time, it has stepless speed regulation performance, can smoothly adjust the rotational speed and torque according to the work requirements, and has strong buffering and vibration absorption capabilities, which can make the start and operation of the drilling rig more stable. However, the transmission efficiency of the hydraulic transmission system is relatively low, especially at low loads, and the system structure is complex, with high maintenance costs. Electric Transmission System Composition and Functions of Components Generator: It converts mechanical energy into electrical energy and provides a power source for the electric transmission system. It is usually driven by a diesel engine or other power sources to generate three-phase alternating current. Electric motor: It converts electrical energy into mechanical energy and drives each working machine of the drilling rig. According to different working requirements, different types and powers of electric motors can be selected. For example, DC motors have good speed regulation performance, and AC variable frequency motors have the advantages of high efficiency, energy conservation, and a wide speed regulation range. Frequency converter: It is used to adjust the power frequency of the AC motor, thereby achieving stepless speed regulation of the motor. By changing the output frequency of the frequency converter, the rotational speed of the motor can be precisely controlled to meet the requirements of different working conditions during the drilling process. Control system: It includes various electrical components, controllers, and sensors, etc., and is used to monitor, control, and protect the electric transmission system. It can realize operations such as starting, stopping, speed regulation, and forward and reverse rotation of the motor, and at the same time monitor parameters such as the voltage, current, and temperature of the system. When an abnormal situation occurs, it will take timely protective measures to ensure the safe operation of the system. Characteristics: The electric transmission system has high transmission efficiency, good speed regulation performance, can achieve precise speed control and torque control, is easy to realize automation and intelligent control, and can improve the efficiency and quality of drilling operations. In addition, the electric transmission system operates stably, has low noise, and causes little pollution to the environment. However, the electric transmission system requires a reliable power supply, has high requirements for the stability of the power grid, and the equipment investment cost is relatively large. Composite Transmission System Composition and Forms: The composite transmission system is a transmission system that combines multiple transmission modes such as mechanical transmission, hydraulic transmission, and electric transmission. Common composite transmission forms include mechanical-hydraulic composite transmission, mechanical-electric composite transmission, and hydraulic-electric composite transmission, etc. For example, in some large oil drilling rigs, the mechanical-hydraulic composite transmission mode of diesel engine-torque converter-gearbox may be adopted to drive the winch, taking advantage of the good adaptability of the torque converter and the high efficiency of gear transmission to meet the working requirements of the winch; at the same time, the electric transmission mode is adopted to drive the rotary table to achieve precise speed regulation and control of the rotary table. Characteristics: The composite transmission system can give full play to the advantages of various transmission modes, select appropriate transmission modes according to the characteristics and working condition requirements of different working machines of the drilling rig, thereby improving the overall performance and adaptability of the drilling rig. It can ensure the reliability and transmission efficiency of the drilling rig while achieving better speed regulation performance and automation control level. However, the system structure is complex, and the design, installation, and maintenance are more difficult.    

The oil drilling rotary swivel is a key piece of equipment in oil, gas and other drilling operations. Today, let's learn about the rotary swivel together. Ⅰ.Working Principle During the drilling process, the swivel is suspended on the traveling block and connected to it through the bail. The winch pulls the traveling block through the wire rope, thus driving the swivel to move up and down. The power equipment (such as the rotary table or top-drive) drives the drill string to rotate, and the central tube of the swivel rotates accordingly, enabling the drill string to carry out rotary drilling. At the same time, the drilling fluid is pumped out from the surface mud pump, enters the central tube through the gooseneck tube, and then flows to the bit through the inside of the drill string, cooling and lubricating the bit and carrying the cuttings to the surface. Ⅱ.Main Functions Torque Transmission: In cooperation with the rotary table or top-drive, it transmits power to the drill string, allowing the bit to rotate and break the rock. Load-Bearing: It suspends the rotating drill string, bears most or even all of the weight of the drill string, provides upper bearing support for it, and at the same time bears various axial and radial loads generated during the drilling process to ensure the stability of the drilling operation. Drilling Fluid Conveyance: As a passage for the drilling fluid, it introduces high-pressure drilling fluid into the rotating drill string, conveys the drilling fluid prepared on the surface to the wellbore, and plays roles such as cooling the bit, carrying cuttings, and stabilizing the wellbore. Ⅲ.Requirements for the Swivel Strength and Rigidity of Load-Bearing Parts: All load-bearing parts need to have sufficient strength and rigidity to bear the entire weight of the drill string and various axial and radial loads generated during the drilling process. For example, for a well several kilometers deep, the weight of the drill string can reach hundreds of tons. The load-bearing components of the swivel, such as the bail and main bearings, need to be reasonably designed and made of excellent materials to meet the load-bearing requirements. Reliable Sealing System: The high-pressure drilling fluid sealing system must work reliably, have a long service life, and be quickly and conveniently replaced to prevent the leakage of drilling fluid and the entry of external impurities. Good Rotation Performance: It should ensure that the drill string can rotate flexibly and stably, with a low friction coefficient and high rotation accuracy. High-quality bearings and a reasonable structural design are the keys to achieving good rotation performance. Good Oil Sealing: The oil seal should be in good condition and be able to automatically compensate for the wear of the sealing elements during the working process. Ⅳ.Composition and Structural Features The swivel generally consists of the following three parts: Load - Bearing SystemIt includes the central tube and its joints, the housing, the trunnions, the lifting bail, and the main bearings, etc. 1.Central Tube: As a passage for the drilling fluid, its internal space allows the drilling fluid to flow smoothly from the surface to the bit. The central tube needs to have good wear - resistance and corrosion - resistance to withstand the long - term scouring and erosion of the drilling fluid. 2.Lifting Bail: It is used to suspend the swivel. By connecting with the traveling block, the swivel can move up and down with the traveling block, thus realizing the tripping operation of the drill string. The bail needs to have sufficient strength to bear the weight of the drill string and various loads generated during the drilling process. 3.Main Bearings: They support the rotation of the central tube, enabling the drill string to rotate flexibly. The main bearings need to have characteristics such as high load-bearing capacity, low friction coefficient, and long service life to ensure stable operation during long-term drilling operations.The weight of the drill string is transmitted to the hook through the kelly, the central tube, the main bearings, the housing, the trunnions, and the bail. Drilling Fluid SystemIt includes the gooseneck tube and the drilling fluid washpipe assembly. 1.Gooseneck Tube: It connects the surface drilling fluid circulation system and the central tube. Its shape is usually gooseneck-like, which is convenient for the introduction of the drilling fluid and, to a certain extent, alleviates the impact force when the drilling fluid flows. 2.Washpipe Assembly: It is installed outside the central tube and plays a sealing role to prevent the drilling fluid from leaking from the gap between the central tube and the swivel housing. The washpipe assembly usually consists of a washpipe, sealing elements, etc. The performance of the sealing elements directly affects the sealing effect of the swivel.High-pressure drilling fluid flows into the rotating central tube through the gooseneck tube and the washpipe and reaches the inside of the drill string. Drilling fluid sealing devices are installed at the upper and lower parts of the washpipe to prevent the leakage of high-pressure drilling fluid. Auxiliary SystemIt includes the centralizing bearings, anti-jump bearings, and oil seal devices.The inner cavity of the housing forms an oil sump to lubricate the main bearings, centralizing bearings, and anti-jump bearings.The upper and lower oil seal boxes are mainly used to prevent the drilling fluid, oil, and water from leaking into the oil sump and the leakage of oil, to ensure the normal operation of each bearing.The upper and lower centralizing bearings radially position the central tube to ensure its stable operation with small swing, to improve the working conditions of the drilling fluid and oil seals and extend their service life.The anti-jump bearings are used to bear the impact and vibration transmitted by the drill string during the drilling process and prevent the axial movement of the central tube. Ⅴ.Maintenance and Upkeep of the Drilling Swivel Daily Inspection 1.Appearance Inspection: Check the appearance of the swivel daily to see if there are obvious signs of wear, cracks, deformation, or leakage. Pay special attention to key parts such as the gooseneck tube, central tube, and bail, as well as the sealing conditions of all connection parts. 2.Connection Parts Inspection: Check whether all connection bolts and nuts are loose to ensure that the connection between the bail and the traveling block, the connection between the gooseneck tube and the drilling fluid manifold, and the connection between the central tube and the drill string are firm and reliable. Loose connections may lead to leakage or equipment failure. 3.Drilling Fluid Passage Inspection: Observe the flow of the drilling fluid to ensure that the drilling fluid passage is unobstructed. Check for any blockages or abnormal pressure fluctuations. If there are any abnormalities, clean or investigate the cause in a timely manner. Lubrication Maintenance 1.Bearing Lubrication: Regularly lubricate the rotating parts of the swivel, such as the main bearings and auxiliary bearings. Use the appropriate lubricant according to the recommendations of the equipment manufacturer and control the amount of lubricant. Over-lubrication may lead to seal failure, while insufficient lubrication will accelerate bearing wear. Generally, set a reasonable lubrication cycle according to the operating environment and usage frequency, such as lubricating after a certain number of working hours or after completing a certain amount of drilling footage. 2.Sealing Element Lubrication: For sealing elements, such as the washpipe seals, proper lubrication is also required to reduce friction and wear and improve the sealing performance. Use a special seal lubricant and apply it according to the specified method and frequency. Maintenance of Rotating Parts 1.Bearing Inspection and Maintenance: In addition to lubrication, regularly check the operating conditions of the bearings, such as whether there are abnormal noises, vibrations, or heat-generation phenomena. If problems are found with the bearings, repair or replace them in a timely manner. Tools such as vibration monitors and temperature sensors can be used to monitor the bearings to detect potential problems at an early stage. 2.Central Tube Rotation Inspection: Ensure that the central tube can rotate flexibly without jamming. Check whether the fit clearance between the central tube and other components is normal. If there are any abnormalities, adjust or repair them in a timely manner. Regular Maintenance and Repair 1.Maintenance Plan Formulation: Formulate a detailed maintenance plan according to the recommendations of the equipment manufacturer and the actual usage situation, including regular comprehensive inspections, maintenance, and repair work. Carry out maintenance according to the plan to ensure that the equipment is always in good operating condition. 2.Professional Repair: For complex faults or repair work, it should be operated by professional repair personnel. The repair personnel should have relevant knowledge and skills, be familiar with the structure and working principle of the swivel, and use appropriate tools and equipment for repair to ensure the repair quality. Ⅵ.Common Faults and Troubleshooting Methods of the Drilling Swivel Leakage of Mud at the Connection between the Gooseneck Tube and the Swivel Flange or the Union of the Water Hose Deterioration or Damage of the Short-shaped Rubber Gasket: Replace the short-shaped rubber gasket. Rust or Damage of the Sealing Surfaces: Clean, derust, or weld - repair each sealing surface. High Temperature and Short Service Life of the Washpipe Lower Packing Box Assembly during Operation Blockage of the Lubricating Oil Nozzle, Inability to Inject Lubricating Grease: Disassemble and clean the blockage of the oil nozzle or replace the parts. Too Tight Fit between the Packing Lip and the Washpipe Sealing Surface            Over-tightening of the Lower Packing Cap: Loosen it and then appropriately adjust the tightness of the lower cap.            Too Small Inner Diameter of the Packing Lip or Too Large Outer Diameter of the Washpipe: Select the appropriate washpipe and packing for assembly. Unsmooth Swing of the Bail or Loose Fit with the Pin Rust or Foreign Matter in the Pin and the Bail Hole: Clean, derust, remove the foreign matter, and then inject lubricating grease. Serious Wear of the Pin and the Hole due to Lack of Oil             Blockage of the Oil Nozzle: Clean the oil nozzle.             Wear of the Pin: Replace the pin. Overheating of the Swivel Housing, Temperature Exceeding 60℃ Lack of Lubricating Oil: Add oil to the oil level gauge scale. Excessive Oil Addition: Open the plug to drain the oil to the oil level gauge scale. Entry of Mud and Other Impurities into the Lubricating Oil: Disassemble the oil drain plug, drain all the oil, clean the housing, and add new oil to the oil level gauge scale. Serious Oil Leakage from the Lower Oil Packing Box during Operation, No Oil in the Housing:Disassemble and inspect to replace the worn-out oil seal sleeves, oil seals, packing and other sealing parts.