Views: 1 Author: Site Editor Publish Time: 2021-10-23 Origin: Site
After the paper machine has been installed and operated for a period of time, the gearbox has leaked to different degrees at each meshing point, forming a gathering oil area at the paper machine base plate. This situation analysis summarizes the following reasons:
(1) Due to the uneven distribution of the mass center of gravity of the drying cylinder (the drying cylinder weighs about 5 tons), and the drying cylinder is heated by steam, during the operation of the equipment, high-pressure steam will form condensate in the drying cylinder. The condensate drainage is unfavorable, and a centrifugal force is formed in the dryer. The dryer can only move to both ends of the dryer to release this force, causing a certain frequency of vibration at the gear mesh. Usually modern multi-cylinder paper machines are composed of 55-80 cylinders. Such vibrations occur together during operation, resulting in leakage at each meshing position, which is the main cause of leakage;
(2) Since the drying cylinder of the paper machine is heated by saturated steam, the steam temperature is 120°C-130°C. The self-absorbing heat of the metal frame in the airtight hood can reach 150℃, and the thermal expansion and contraction make the gap between the matching positions of individual parts too large (such as the joint point of the drying cylinder and the gear box), resulting in leakage;
(3) Apply sealant between the meshing surfaces of each part of the gearbox, and long-term high-temperature vibration will cause the seal to fail and leak;
(4) The gearbox of the paper machine is a casting, which must be treated with aging during the production process. If the aging time is short, the internal stress of the gearbox is not completely eliminated, and the installed gearbox will continue to deform during operation, which will lead to leakage;
(5) In the process of installation or maintenance, the material of the bearing gland, gear gland, and gear axle shaft is different, and the coefficient of thermal expansion during operation is also different. Therefore, the expansion gap is required to be greater than a certain standard during installation. In the actual operation and installation process of the gearbox, due to improper maintenance and installation process, the expansion gap is less than the standard value, which will cause the gearbox to withstand the strong expansion force of the components in the gearbox during operation, resulting in deformation and leakage;
(6) In order to ensure the sealing effect of the joint surface of the gearbox of the paper machine, there are also clear regulations on the extension of the cold and hot tightening bolts of each bolt. However, in the actual maintenance work, if the bolts are not tightened as required, the joint surface will deform and leak.