Introducing an on-site repair technology for bearing wear in tube bundle dryers (case)

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The bearing position and spacer sleeve installation position of the tube bundle dryer in the starch workshop of a biotechnology company showed wear. The maximum wear amount reached 1cm. The matching form from front to back is as follows: Pressure plate, large gear, spacer sleeve, adapter sleeve, spacer sleeve. After analysis, it is believed that the cause of the wear of the bearing position and spacer sleeve is that the gear pressure plate and the adapter sleeve pressure plate are loose or the preload force is insufficient, causing the adapter sleeve, spacer sleeve and the shaft to move relative to each other, resulting in wear of the shaft diameter. 1. Comparison of several common repair processes. For this kind of transmission part wear problem, the traditional repair process often involves disassembling the equipment and transporting it to a machine repair shop for repair welding processing. The downtime is long, and the repair welding process can easily cause thermal stress, leading to shaft deformation and bending, causing irreversible damage. The traditional brush plating treatment generally has requirements on the thickness of the coating and cannot reach centimeter-level thickness. In addition, no matter which of the above repair processes is used, it is impossible to achieve the conditions for equipment startup and operation in the short term. Therefore, the above solutions are obviously not suitable for the repair requirements of the dryer shaft wear. In view of the wear of the shaft, an on-site repair plan using polymer composite materials was determined based on several traditional repair processes. For bearing wear problems, polymer composite materials can select different equipment repair processes based on equipment speed, bearing model, usage requirements and other parameters. Among them, the most commonly used is the mold repair process (see the figure below). This repair process uses material characteristics and combines the actual conditions of the site to process repair tooling. It is an on-site repair process that uses the molding method to repair worn parts according to the positioning parts. It has the characteristics of short repair time, high repair accuracy, low repair cost, no secondary damage to the equipment, and easy operation. 2. Plan implementation process 1. First, bake the worn parts with oil to remove the grease that has penetrated into the metal micropores. ； 2. Use a polisher to polish the worn area and clean it with alcohol or acetone. ； 3. Assemble the mold to the repaired part, observe the fastening of the mold, then disassemble and apply release agent for later use. ； 4. Mix 2211F metal repair material according to the proportion and stir evenly until there is no color difference. ； 5. Use 2211F metal repair material to fill in the worn position and slightly exceed the wear amount. ； 6. Assemble the mold and wait for the material to solidify ； 7. After curing, disassemble the mold and remove excess material, then apply material again to assemble the adapter sleeve, spacer sleeve and bearing. 8. Check the pressure plate in time when the machine is shut down during later use, and deal with any looseness in time.