Installation details of mechanical seals for pumps and kettles that cannot be ignored

The correct installation and use of pump mechanical seals can prolong the service life of pump mechanical seals and reduce operating costs. Make meticulous work for each link to ensure the operation of the whole machine and the normal progress of production. So what are the details that cannot be ignored in the installation of mechanical seals for pumps?

1. The area of ​​the shaft sleeve where the mechanical seal is installed should be coated with a thin layer of oil, but if ethylene-propylene, butyl and other rubber sealing elements are used, they should not be in contact with mineral oil and grease. In this case, it is recommended to use Detergent or soap solution for lubrication. This is done to reduce frictional resistance.

2. During installation, attention should be paid to distinguish the installation direction of the left and right static rings and the shaft sleeve. When installing a mechanical seal that prevents axial displacement of the static ring, the snap ring must be placed in the corresponding position of the seal cavity. When installing the mechanical seal, the set screw should be evenly tightened several times. Before fixing the gland, check whether there are foreign particles attached to the friction end face. Push the compensation ring by hand for axial compression. After loosening, the compensation ring can automatically bounce. If there is no sticking phenomenon, then tighten the gland screws evenly.

Installation details of mechanical seals for pumps that cannot be ignored (Fig. 1)

3. When installing the sealing ring covered with PTPE, the outer seam must be away from the installation direction. Severely bending PTPE will lead to failure. When installing the sealing ring of pure PTFE, it needs enough time and slight force to avoid scratches, otherwise it will cause failure. When installing the PTFE V-ring, its V-shaped port must face the high pressure side. When installing the wedge-shaped seal ring, if there is a mounting clip on the spring seat, it should be removed after the mechanical seal is installed on the shaft or shaft sleeve. When installing a mechanical seal that rotates in one direction and adopts a parallel spring drive, special attention should be paid to the direction of rotation of the spring. From the static ring to the rotating ring, the clockwise rotating shaft needs a right-handed spring, otherwise it is a left-handed spring. When installing flexible graphite, the axial bolts should be tightened in sequence in a dry state, so that the flexible graphite can be fully deformed twice, and remember not to cross-tighten.

4. Generally, the shaft sleeve of the cantilever pump is directly pressed and fixed by the impeller, and the key is used for transmission. When installing, according to the custom, first put the whole set of seals on the shaft, install the pump cover, and fix the seal gland. Note that the shaft seal and gland gasket are in place. After fixing the pump cover and the suspension, install the key, impeller and other parts.

5. When tightening the nuts that fix the gland, tighten the nuts evenly to prevent the gland from skewing. After tightening the nut, pay attention to check whether the gap between the gland and the shaft is uniform. If there is any interference, it needs to be disassembled and adjusted to avoid damage to the seal.

6. Assemble the remaining parts of the pump. After installation, turn the pump shaft to check whether there is friction between the static ring, the gland and the shaft sleeve, and between the rotating parts and the sealing chamber. The pump shaft should feel evenly applied after one rotation. If the shaft cannot be rotated or the local force is very large after one rotation, the seal should be checked for installation problems and reinstalled if necessary. It is worth noting that the seal should not be knocked during the assembly process. After the seal is assembled, it should not be knocked or impacted on the shaft, the shaft sleeve and the seal end cap, etc., to avoid damage to the seal ring.

7. After the pump is in place at the site, according to the working structure of the pump or seal, connect the pipeline of the auxiliary seal system. At the same time, ensure that the pipeline system is clean and the working environment of the mechanical seal is clean and tidy. Pay attention to the arrangement of the pipeline to prevent the local residual gas from affecting the circulation.