1. Use of mining axial-flow counter-rotating main fans The FKD and FK series axial fans are successfully designed on the basis of the original energy-saving fans used in coal mines through technical improvement, improvement of structure, and improvement of performance. They have the unique advantages of high aerodynamic efficiency, being well matched with the ventilation network, and having extremely significant energy-saving effects; this series of energy-saving fans have been used in many mines in the country's metallurgical, nonferrous metals, gold, chemical, building materials and nuclear industries. This series of mining energy-saving fans are generally used in the main fans, auxiliary fans, and local fans used in large and medium-sized key mines in various systems, and ideal technical results and economic benefits have been achieved.   In order to expand the performance range of this series of fans and meet the needs of non-coal mines of various large, medium and large fans, all types of ventilation networks with low, medium and high resistance and large, medium and small air volumes can be selected to operate in high-efficiency areas. Main fans, auxiliary fans and multi-stage fan stations are used. This series of fans adopts three hub ratios of 0.40, 0.54, and 0.60, and two structural types: single machine and counter-rotating.   2. Characteristics of mining axial-flow counter-rotating main fans 1. Structural characteristics of the fan (1). FKD series fans are composed of collector, primary main machine, secondary main machine, diffuser, round-to-square joint, muffler, diffusion tower and other components; FK series fans are composed of collector, main machine, diffuser and other components. Each component is connected with bolts for easy maintenance.   (2) This series of fans adopts a direct connection between the motor and the impeller, which reduces ventilation resistance losses such as the S-type air duct, improves efficiency, and also reduces safety hazards and maintenance troubles caused by the S-type air   (3) The two-stage working impellers of the FKD series fans rotate in opposite directions. The first and second stages of blades are each other's guide vanes, and there is no fixed guide vane, which reduces the energy consumption of the guide vanes, simplifies the structure, and improves efficiency.   FK series fans are composed of a set of impellers and static guide vanes;(4) FKD and FK series fans are equipped with high-quality fan special motors, and the motors are placed in the flow channel for easy heat dissipation and diversion. This is conducive to the heat dissipation of the motor, thereby increasing the safety of the fan operation.   (5). FKD and FK series fans are equipped with non-stop refueling devices and oil discharge devices, which can be filled with lubricating oil during operation. When stopping, the oil discharge cap can be opened to eliminate waste oil.   (6) Temperature measuring elements are embedded between the bearings and stator windings of the motor, which can display the temperature of each part of the fan during operation.   (9) The wind blades adopt a twisted wing shape, which has good aerodynamic performance, a wide efficient area, and significant energy-saving effect.   (10) The blades are adjustable structures, and the blade angle can be adjusted according to different working conditions to keep the fan running in the efficient area.   2. Performance characteristics of fans (1). This series is a highly efficient, energy-saving, low-noise, and large air volume fan.   (2) The hump area of this series of fans is narrow and the wind pressure is relatively stable, the airflow surge phenomenon is weak, and the airflow is stable.   (3) This series of fans has a wide range of efficient areas and can adapt to changes in mine production. When ventilation parameters change, they still operate at high efficiency.   (4) According to production needs, the cyclone machine can also be operated alone. Compared with stand-alone operation, the air volume for the cyclone machine can be increased by 45%-70%, and the wind pressure is increased by-192%. Compared with series operation, the air volume is increased by about 20%, and the wind pressure is increased by about 50%.   3. Description of the special components supporting the main axial flow counter-rotating fan for mining (1). Silencers This series of silencers is a muffler specially designed and supporting fan. It adopts a composite and muffler wall combination structure to solve the problem of high outlet noise of the axial flow fan, thereby ensuring a good environment for users. The performance of the fan is fully considered in design, and the internal structure of the muffler is optimized to greatly reduce its resistance; the manufacturing process takes into account the user's on-site environment and adopts anti-corrosion measures.   (2) Diffusion towers This series of diffusion towers are designed with streamlined shapes to ensure that the direction of air flow does not change during the change process. Its first role is to change the direction of air flow, protect the surrounding environment and reduce noise; its second role is to reduce the dynamic pressure loss of the fan, convert it into effective static pressure, and improve the efficiency of the fan.   (3) Online monitoring and early warning system This system can accurately reflect and record the operating curve, wind pressure, air volume, wind speed, bearing and stator temperature, current, voltage, vibration and other parameters of the fan, and can record, archive and fault alarm. It can be called up from the computer at any time, which belongs to the advanced domestic technology.   (4) Supporting fan special distribution system This system is specially designed according to the requirements of the "Coal Mine Safety Regulations" and the particularity of the fan to meet various protections for the fan motor (motor overload, loss of voltage, short circuit and other protections).   (5). Damper This series of fans can be equipped with different types of dampers according to user needs. One is a butterfly valve plus test air duct, and the other is a fully sealed damper. The above air doors can be equipped with automatic control systems to control the opening and closing of the air doors.   3. Installation and debugging of mining axial-flow counter-rotating main fans 1. Handle the installation site according to the fan specifications, and the ground of the base must be flat and consolidated.   2. Before installation, all parts of the fan must be inspected: a. Whether the parts are complete;b. Whether the impeller is flexible;c. Whether the blade rubs against the cylinder wall;d. Whether the blade is installed firmly;e. Whether the blade is damaged. Problems discovered must be dealt with in a timely manner, and hidden dangers of accidents must never be allowed.   3. During installation, hoist the various components of the fan to the laid rails in order, pad the sealing rings where needed, connect the various components firmly with bolts, and connect the power cord and the thermometer gauge cord according to the motor's instructions.   4. Check whether the inlet and outlet oil circuits are smooth, and inject No. 2 molybdenum disulfide lithium-based lubricating oil (or better quality lubricating grease).   5. Check each component, and after the manual brake is correct, you can carry out trial operation.   6. For motors that have been transported for long distances or have been used for a long time, the insulation resistance of the stator must be measured before use (the insulation resistance must not be less than 0.5 megohm 380V). Only after passing the inspection can the power supply be connected and the fan can be started. During trial operation, the current, voltage, motor stator and bearing temperature should be observed frequently, and any abnormalities should be found should be stopped immediately for inspection.   4. Operation and maintenance of mining axial-flow counter-rotating main fans 1. Before starting the fan, it is necessary to check whether there is any foreign matter in the flow passage to prevent the impeller of the fan from being hit by foreign matter and causing damage to it.   2. Before starting the fan, please read the starting instructions and the motor operating instructions in detail, and operate the starting equipment as required. FKD starts the fan in the order of the first stage and the second stage (FK starts directly), and adjusts the rotation direction to ensure the normal operation of the fan.   3. Observe in time after the fan starts and reaches normal operation: a. Whether the current of the motor exceeds the rated current;b. Whether there is any abnormal sound in the fan flow channel. If any problem is found, stop the machine for inspection in time, and only enter normal operation after the cause is ascertained and the fault is eliminated.   4. During the use of the fan, operation records should be provided, and the system should record the operation of the fan, including: a. The fan start-up and shutdown time, reasons for shutdown;b. ambient temperature, humidity and atmospheric pressure;c. motor working voltage, working current, temperature of each bearing, and temperature of the motor stator. Items exceeding the indicators must be stopped immediately for inspection;d. Air pressure and air volume of the fan;e. Time, quantity and brand of molybdenum disulfide lithium-based lubricating oil for motor bearings;f. Abnormal conditions found during regular inspections;g. Details of the failure and elimination.   5. During the operation of the fan, the motor must be maintained according to the motor manufacturer's instructions, and appropriate amount of molybdenum disulfide lithium-based lubricating oil must be added.   6. Regularly stop the fan and comprehensively check whether each component meets the requirements: a. Check the front and rear bearings of the motor. If you find a problem, replace the bearing according to the model and replace the molybdenum disulfide lithium-based lubricant.   b. Check whether the blade is loose and whether the installation angle of the blade is the same as originally set. Problems discovered must be dealt with in a timely manner.   c. Adjustment method of blade installation angle: Select the required installation angle according to the characteristic curve of the fan and the ventilation requirements of the mine. Open the hub cover plate, loosen the leaf nut, press the selected installation angle on the scale on the hub drum surface, align the front of the blade with the scale line, disable the leaf nut, lock the nut, cover the cover plate, and the adjustment is completed.   Note: After blade adjustment is completed, be sure to check whether the installation angles of each blade are consistent, otherwise it will be adjusted again.   8. Always check the reliability of measuring instruments to prevent accidents caused by failure of thermometers, ammeters, etc.   9. Drivers, etc. conduct frequent inspections. Once abnormal sounds, vibration, heating, etc. are found, they should immediately stop the machine and handle it, and can only be started after the fault is eliminated.   5. Inspection and transportation of mining axial-flow counter-rotating main fans 1. The fan has been debugged before leaving the factory and passed the inspection. Adopt simple packaging.   2. The whole machine of the small fan is shipped from the factory, and the main machine of the large fan, the diffuser and its accessories are manufactured and transported separately.   3. This series of fans can be transported by land or water.   4. Carry a packing list, instructions for use, and product certificate at random.