For pumps that cannot be ignored Mechanical seal for kettle Installation details

The correct installation and use of pump mechanical seal can extend the service life of pump mechanical seal and reduce operating costs. Work carefully for each link to ensure the normal operation and production of the whole machine. What details can not be ignored in the installation of mechanical seals for pumps?

1. The shaft sleeve area where the mechanical seal is installed shall be coated with a thin layer of oil. However, if ethylene propylene, butyl and other rubber sealing elements are selected, they cannot contact with mineral oil and grease. In this case, detergent or soap liquid is recommended for lubrication. This is done to reduce frictional resistance.

2. During installation, attention shall be paid to distinguishing the installation directions of left and right stationary rings and shaft sleeves. When installing mechanical seals that prevent axial displacement of stationary rings, snap rings must be placed at the corresponding positions of seal cavities. When installing the mechanical seal set screws, they should be tightened evenly in several times. Before fixing the gland, check whether there are foreign particles attached to the friction end face. Push the compensation ring manually for axial compression. After loosening, the compensation ring can spring back automatically without stagnation, and then lock the gland screws evenly.

Installation details of mechanical seal for pump that cannot be ignored (Fig. 1)

3. When installing the sealing ring wrapped with PTPE, the outer seam must be away from the installation direction. Severe bending of PTPE will lead to failure. When installing the pure tetrafluoroethylene sealing ring, it needs enough time and slight force to avoid scratches, otherwise it will cause failure. When installing the PTFE V-ring, its V-mouth must face the high-pressure side. When installing the wedge seal ring, if there is a mounting clip on the spring seat, remove the mechanical seal after installing the shaft or shaft sleeve. When installing the mechanical seal with one-way rotation and parallel coil spring transmission, pay special attention to the rotation direction of the spring. From the static ring to the rotating ring, the clockwise rotating shaft needs a right rotating spring, and vice versa. When installing the flexible graphite, the axial bolts shall be tightened in sequence in a dry state to make the flexible graphite fully deformed for the second time. Remember not to cross tighten.

4. Generally, the shaft sleeve of the cantilever pump is directly pressed and fixed by the impeller and driven by the key. During installation, the complete set of seals can be installed on the shaft, the pump cover can be installed, and the seal gland can be fixed according to the custom. Note that the shaft seal gasket and gland gasket shall be installed in place. After fixing the pump cover and the suspension, install the key, impeller and other parts.

5. When tightening the nuts for fixing the gland, tighten the nuts evenly to avoid the deflection of the gland. After tightening the nuts, pay attention to check whether the clearance between the gland and the shaft is even. If there is interference, it needs to be disassembled and adjusted to avoid damage to the seal.

6. Assemble the other parts of the pump. After installation, rotate the pump shaft to check whether there is friction between the stationary ring, gland and shaft sleeve, and between the rotating part and the seal chamber. The force should be uniform when the pump shaft rotates for one week. If the shaft cannot be rotated or the local force is too large for one revolution, check the seal for installation problems, and reinstall it if necessary. It is worth noting that the seal shall not be knocked during the assembly process. After the seal assembly is completed, the shaft, shaft sleeve and seal end cover shall not be knocked or impacted to avoid damage to the seal ring.

7. After the pump is in place at the site, the pipeline of the auxiliary sealing system shall be connected according to the pump or sealing working structure. At the same time, the pipeline system shall be kept clean, and the working environment of the mechanical seal shall be kept clean. Pay attention to the pipeline layout to prevent local trapped gas from affecting the circulation.