Detailed steps and techniques for replacing mechanical seals of various water pumps

Detailed steps and techniques for replacing mechanical seals of various water pumps In order to ensure the normal operation of water pumps, the mechanical seals are generally replaced once every three months. This article provides detailed instructions on how to replace the mechanical seals and the steps for replacing the mechanical seals for your reference. Tools and materials Adjustable wrenches, socket wrenches, flat-blade screwdrivers, flat-blade screwdrivers, sandpaper, clean cotton cloth, grease repair workbench, and a new set of mechanical seals. The method of changing the mechanical seal of the water pump: 1. Install the left part first; install it on the sealing plate 2. Then install the moving ring on the right side of the mechanical seal. The sealing surface of the moving ring and the static ring should be clean. 3. Install the flat key and the good gasket on the impeller. Nut. Before installation, carefully check whether the number of assembled sealing parts is sufficient, whether each component is damaged, especially whether the mechanical seal is damaged, cracks, deformation, etc. in the moving and static rings. If there is a problem, it needs to be repaired or replaced with new spare parts. Check whether the chamfer of the shaft sleeve or gland is proper, if it does not meet the requirements, it must be trimmed. All components of the mechanical seal and their related assembly contact surfaces must be cleaned with acetone or absolute alcohol before installation. The installation process should be kept clean, especially the dynamic and static rings and auxiliary sealing components should be free of impurities and dust. Coat the surface of the moving and static rings with a layer of clean engine oil or turbine oil. The gland should be tightened after the coupling is aligned. The bolts should be tightened evenly to prevent the gland section from deviating. Check each point with a feeler gauge or special tools, and the error should not exceed 005 mm. Check the matching clearance (and concentricity) between the gland and the outer diameter of the shaft or bushing, and ensure that the surroundings are even. Use a feeler gauge to check that the tolerance of each point is not more than 010 mm. The compression of the spring should be carried out according to the regulations. It is not allowed to be too large or too small. The error is required to be ±200 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, the specific pressure will be insufficient and it will not be able to 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. After the moving ring is pressed against the spring, it should automatically spring back. Put the static ring sealing ring on the back of the static ring first, and then install it into the sealing end cover. Pay attention to the protection of 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 never allowed to directly knock the sealing element with tools. When it is necessary to strike, special tools must be used to strike to prevent damage to the sealing element. All sealing rings should be coated with soapy water and other lubricants during assembly, so as to avoid the assembly process. Damage to the rubber ring. Grease is applied between the sealing surfaces of the moving and static rings to prevent the sealing surfaces of the moving and static rings from wearing before the pump starts. When assembling the floating ring, be careful not to knock down the floating ring spring, 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 gently press the floating ring to determine whether there is 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 force from damaging the mechanical seal. For quick-fitting mechanical seals, do not forget to fix the position of the positioning piece radially away from the shaft after the overall assembly is completed. Because the medium sealed by the mechanical seal is different, the temperature of cold water and hot water is different, whether the sealed medium is corrosive, the pressure in the chamber is different, the design of the mechanical seal will be different, and the maintenance process will also be different. Some experience was summed up in the process of seal maintenance: mechanical seals must be assembled, and do not forget to clean and inspect. Look at the two rings first and then the shaft. Don't leak the scars or cracks. Finally, when looking at the rubber ring, the diameter of the air hole must be clearly seen. Various sizes need to be measured, and the gap between the two rings should be adjusted. The tightness must be checked, and the small spring is the key. The bolts must be evenly stressed, and it is a good habit to handle them gently. The mechanical seal of the water pump is one of the most effective ways to seal the main body of the rotating machinery. Its processing accuracy is relatively high, especially the dynamic and static rings. If the disassembly method is improper or improperly used, the mechanical seal after assembly will not only fail to seal. The purpose of this, and it will damage the assembled sealing element. Precautions when disassembling the mechanical seal When disassembling the mechanical seal, it is strictly forbidden to use hand hammers and flat shovel to avoid damage to the sealing elements. If there are mechanical seals at both ends of the pump, care must be taken during the disassembly process to prevent one from losing one's attention. For the mechanical seal that has been worked, if the sealing surface moves 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 original running track of the friction pair will change, and the sealing of the contact surface is easily damaged. If the sealing element is bonded by dirt or condensate, the condensate should be removed before disassembling the mechanical seal. Pumps that use mechanical seals include: chemical pumps, centrifugal pumps, multi-stage pumps, self-priming pumps and various sewage pump products. Keywords: mechanical seals, mechanical seals