Air-cooled fan

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Working principle of axial flow fans (airfoil lift principle): Fluid flows axially into the blade channels. As the impeller rotates driven by the motor, the rotating blades exert an axial thrust on the fluid flowing around them. According to fluid dynamics principles, as the fluid flows around the blades, it exerts a lifting force on the blades; meanwhile, based on the principle of action and reaction, the blades also exert a force on the fluid that is equal in magnitude but opposite in direction to the lifting force, namely thrust. This thrust does work on the fluid, increasing its energy and causing it to be discharged axially. The continuous rotation of the blades results in the continuous operation of an axial flow fan. 1. Disassembly of the air-cooled fan: ① Ensure power is off and that all safety measures have been implemented before disassembly ； ②Start removing the protective net, removing it from both sides simultaneously and coordinating the process ； ③Stabilize the A-frame ladder and get ready to enter the tube bundle enclosure; be careful to avoid heat stroke when the temperature is high ； ④Loosen the motor fastening bolts and tensioning bolts, then remove the belt (you can use a rope to pull the belt when removing it; it’s better not to pull it with your hands directly) ； ⑤The hub and shaft are fitted together using tapered sleeves; make proper markings. First, loosen the fastening bolts on the tapered sleeves, then use jacks to push on the hub symmetrically and evenly until it becomes loose ； ⑥Use a chisel to widen the opening of the tapered sleeve, then remove the tapered sleeve ； ⑦Remove the bolts of the upper bearing seat, then loosen the bolts of the lower bearing seat; be careful not to remove them ； ⑧Use a puller to push the shaft out, tie up the pulley, remove the bolts of the lower bearing housing, and place it on the ground slowly, being careful to ensure safety ； ⑨Make proper markings, loosen the bolts holding the tapered sleeve on the pulley, use a jacking rod to push the pulley out, then use a chisel to pry open the tapered sleeve and remove it, placing it in a suitable location; ⑩ Use a snap ring plier to remove the snap ring, and use a puller to extract the lower bearing housing ； Use a chisel to remove the upper and lower bearings; once removal is complete, clean all the components. 2. Inspection of various components: ① Check the wear condition of the shafts, and verify whether there are any scratches or deformations on the contact surfaces ； ② The bending degree of the measuring axis is required to be within 0.05 mm ； ③ Check the wear condition of the bearing: whether there are pitting on the rolling elements, any damage on the inner and outer raceways, as well as the fit between the bearing and the shaft and the bearing housing. The fit between the bearing and the shaft is H7/Js6, while the fit between the bearing and the bearing housing is K7/H6 ； ④ Check whether the belt is aged or broken ； ⑤ Check for cracks in the blades and ensure that the bolts are tight ； ⑥ Once the above issues are resolved, it can be installed. 3. Assembly of the air-cooled fan: ① Apply butter to the lower bearing seat and install the bearing ； ②Install the lower bearing housing and bearings on the shaft, then fit the tapered sleeve (aligning it with the previous markings), followed by installing the pulley; tighten it multiple times ； ③Lift the pulley together with the shaft, install it on the frame, and attach the lower bearing housing bolts ； ④After tightening the bolts, install the bearing housing and bearings, and tighten the bolts of the bearing housing ； ⑤Install the taper sleeve, blades, and hub, aligning with the original markings ； ⑥After installing the blades, use an adjustable angle square to correct their angle. ⑦ Install the belt and adjust its tightness ； ⑧ Install a protective net. 4. Safety precautions for maintenance 1) Before maintaining the equipment, it is necessary to clean it thoroughly; once cleaning is complete, the handover procedures for maintenance should be carried out. 2) Before performing maintenance on the equipment, the power supply must be disconnected. After conducting a second voltage check, a “Do Not Close” sign should be placed on the power source before starting the maintenance work. 3) When lifting and transporting equipment as well as parts and components, there must be a dedicated person to give instructions, and another dedicated person to operate the lifting equipment. The appropriate lifting ropes must be used, and lifting under overload is strictly prohibited. It is also forbidden for anyone to walk or stay under the lifted objects. 4) Maintenance tools, as well as the components that need to be removed, cleaned, or replaced, should be placed neatly in designated areas, to keep the work area clean and unobstructed.