Mechanical seal for kettle Repair plan
With the requirements of production safety and environmental protection, mechanical seals are used more and more widely. At present, most of the rotating equipment in enterprises use mechanical seals to protect the dynamic and static sealing surfaces from leakage, but mechanical seals are relatively precise parts of the equipment
In the process of operation and maintenance, the requirements for technicians are relatively high. Here are some problems about mechanical seal repair.
1. Installation of mechanical seal
Most of the reasons for the good or bad operation and the long or short life of the mechanical seal in the use process are the working environment of the mechanical seal given by the equipment itself. Therefore, it is necessary to carefully check the equipment before installing the mechanical seal, which will reduce the possibility of mechanical seal failure and improve the mechanical seal performance
The service life of the equipment shall be checked in the following aspects:
(1) The hole diameter and depth dimension of the seal chamber shall be the same as those on the installation drawing of the seal components, and the general tolerance shall be within ± 0.13mm; The dimensional deviation between the shaft and the shaft sleeve shall be within ± 0.03 - ± 0.05. The axial displacement of the shaft shall be checked, and the total displacement shall not exceed 0.25mm in theory; Axial
The radial runout is generally less than 0.05mm. Excessive radial runout may cause wear between seal shaft sleeve and shaft; The self inspection leakage of the sealing surface increases, thus affecting the overall working environment of the seal and reducing the service life of the seal
(2) Check the bending of the shaft, and the maximum bending should be less than 0.07mm.
(3) The alignment between the seal cavity hole and the shaft should be less than 0.13mm. The misalignment between the seal cavity hole and the shaft will affect the dynamic load between the sealing surfaces, thus reducing the seal operating life.
2. Check the seal before installation
Whether it is a new mechanical seal or a repaired mechanical if, the following items need to be carefully checked: check all parts, which should be clean and free of dirt, especially the sealing surface; Check that the rotating parts, transmission pins and spring pins can move freely; Check the set screws of rotating parts.
3. Startup and use of mechanical seal
Correct use is critical to the service life of mechanical seals. Generally, the following precautions are used for trial and most mechanical seals
(1) Most mechanical seals are designed to work in a liquid environment, so the sealing surface must be immersed in liquid before starting. Dry operation may damage the sealing surface and affect the service life. Inching equipment has little influence, but full speed operation needs to ensure that the sealing equipment is in the working fluid.
(2) It is better not to cut off the cooling or flushing system, no matter whether the equipment is running or not, especially when the hot medium transported by the equipment will crystallize after cooling.
(3) It is normal for newly installed equipment to have slight leakage at the first operation. With the running in of the seal, the leakage will be reduced to no leakage.
