Detailed steps and techniques for replacing mechanical seals in various water pumps
In order to ensure the normal operation of the water pump, the
mechanical seal is generally replaced once every three months. This article describes in detail how to replace the mechanical seal and the steps for replacing the mechanical seal for your reference. Tools and Materials Adjustable wrench, socket wrench, flat-blade screwdriver, flat-blade screwdriver, sandpaper, clean cotton cloth, grease repair workbench, new set of machine 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 mechanical seal on the moving ring on the right. The sealing surfaces of the moving ring and the static ring should be clean. 3. Then install the flat key and the gasket on the impeller. nut. Before installation, carefully check whether the number of assembled sealing parts is sufficient and whether each component is damaged, especially whether the dynamic and static rings of the mechanical seal have defects such as bumps, cracks and deformations. If there is a problem, it needs to be repaired or replaced with a new spare part. 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 and their related assembly contact surfaces must be cleaned with acetone or anhydrous alcohol before installation. It should be kept clean during installation, especially the dynamic and static rings and auxiliary sealing elements should be free of impurities and dust. Apply a layer of clean engine oil or turbine 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 evenly tightened to prevent deflection of the gland section. Use a feeler gauge or special tool to check each point, and the error should not exceed 005 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 the circumference. 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. 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, 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. For the quick-installed mechanical seal, do not forget to fix the position of the radial movement of the positioning piece 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, and 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: the mechanical seal should be assembled, and the cleaning and inspection should not be forgotten. Look at the two rings first, then look at the shaft. Do not leak the scars and cracks. Finally, when looking at the rubber ring, the diameter of the air hole should 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 force of the bolts should be uniform, and it is a good habit to handle with care. The mechanical seal of the water pump is one of the most effective ways to seal the body of the rotating machinery. purpose, and will damage the built-up sealing elements. Precautions when disassembling 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 at both ends of the pump, care must be taken during disassembly to prevent one from losing the other. For the mechanical seal that has 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 to continue use. Because after loosening, the original running track of the friction pair will change, and the sealing of the contact surface will be easily damaged. If the sealing element is stuck by dirt or condensate, remove the condensate before disassembling the mechanical seal. Pumps with mechanical seals include: chemical pumps, centrifugal pumps, multi-stage pumps, self-priming pumps and various sewage pump products.
