Shaft seal device
The seal between the rotating shaft and the fixed housing is called the shaft seal. Its function is to prevent liquid leakage from the pump to the outside, or when the pressure in the pump is lower than atmospheric pressure, to prevent air leakage into the pump. Although the position of the shaft seal device is not large, it is very important for the normal operation of the machine, and it is one of the most prone parts to failure. The most commonly used shaft seal devices are packing seal, mechanical seal and floating seal. The requirements of the design of the sealing device are reliable sealing, long-term operation, low power consumption and adaptation to the change of pump operation state
In addition, the performance, temperature and pressure of the liquid should be considered。
1. Packing seal
Fig. 1-64 is the most widely used soft packing seal, also known as packing box seal. It uses oil-immersed graphite asbestos rope as the packing, which is placed in the packing box (packing box), compressed by the sleeve and gland, and achieved the seal by the deformation of the packing. When soft packing is used, a liquid seal ring is installed in the middle of the packing layer to introduce high-pressure liquid flow here, which can not only seal, but also lubricate and cool. In order to avoid too much friction between the packing and the pump shaft, the compactness of the packing should not be too large.
There are many kinds of fillers. In addition to asbestos, the basic materials can also be metal synthetic rubber, synthetic resin, leather shed hemp, slurry pump manufacturers, flexible asbestos fillers suitable for high and low temperature corrosive media and carbon fiber fillers suitable for high speed and high pressure,