Correct disassembly and inspection method of mechanical seal

Correct disassembly and inspection method of mechanical seal

Precautions and repair methods when disassembling and inspecting the mechanical seal; when disassembling the mechanical seal, it is strictly forbidden to use a hand hammer and a flat shovel to avoid damage to the sealing element. If there are mechanical seals on both ends of the pump, care must be taken during disassembly to prevent damage. For the used mechanical seal, if the mechanical seal moves on the sealing surface when the gland is loose, the dynamic and static ring parts should be replaced, and should not be re-tightened for continued use. Because after loosening, the mechanical seal track of the original running rail of the friction pair will change, and the sealing of the contact surface is easily damaged. If the sealing element is stuck by dirt or condensate, remove the condensate before disassembling the mechanical seal. Before installation, carefully check whether the number of assembly sealing parts is sufficient, whether each component is damaged, especially whether the dynamic and static rings have defects such as bumps, cracks and deformation. If there is a problem, it needs to be repaired or replaced. Check whether the chamfer of the bushing or gland is appropriate, if it does not meet the requirements, it must be trimmed. The components of the mechanical seal must be cleaned with acetone or anhydrous alcohol for the mechanical shaft seal before installation. Keep it clean, especially the moving and static rings and auxiliary sealing elements should be free of impurities and dust. Apply a layer of clean engine oil to the surfaces of the dynamic and static rings. Tightening of the gland should be carried out after the coupling is aligned. The bolts should be tightened evenly to prevent the section of the gland from being deflected. Check each point with a feeler gauge or a special tool, and the error should not be greater than 0.05 mm. Check the matching clearance (and concentricity) between the gland and the shaft or the outer diameter of the shaft sleeve. It must be uniform around it. Use a feeler gauge to check that the tolerance at each point is not greater than 0.10 mm. The amount of spring compression should be carried out according to the regulations, and it is not allowed to be too large or too small. The error is required to be ±2.00 mm. If it is too large, it will increase the specific pressure of the section and accelerate the wear of the section. If it is too small, it will cause insufficient specific pressure and cannot play a sealing role. After the spring is installed, it must move flexibly in the spring seat. When using a single spring, pay attention to the direction of rotation of the spring. The direction of rotation of the spring should be opposite to the direction of rotation of the shaft. After the moving ring is installed, it must keep moving flexibly, and it should be able to spring back automatically after pressing the moving ring against the spring. First put the static ring sealing ring on the back of the static ring, and then put it into the sealing end cover. Pay attention to protect the static ring section, ensure the verticality of the static ring section and the center line of the end cover, and align the anti-rotation groove on the back of the static ring with the anti-rotation pin, but do not make them touch each other. During the installation process, it is not allowed to directly hit the sealing element with a tool. When it needs to be hit, it must be hit with a special tool to prevent damage to the sealing element. All sealing rings should be coated with soap and water and other lubricants during assembly, so as to avoid the assembly process. Damaged rubber ring. Grease is applied between the sealing surfaces of the dynamic and static rings to prevent the sealing surfaces of the dynamic and static rings from being worn before the pump starts. When assembling the floating ring, be careful not to knock down the spring of the floating ring, so as not to affect the floating performance of the floating ring after the spring is knocked down. After the floating ring is assembled, you can press the floating ring lightly to determine whether it has good floating performance. When installing the seal, handle it with care to prevent damage to the seal, and clean the seal and cavity during installation. When tightening the mechanical seal gland, the tightening bolts should be evenly stressed to prevent uneven stress from damaging the mechanical seal.