Address:Jinghu District Wuhu City, Anhui Province, China
TJ-0762-21-2 shaft seal
TJ-0762-21-2 shaft seal
Shaft seal is a friction seal or packing box used to prevent liquid leakage between the shaft and bearings of compressors or other fluid conveying equipment, and is also a sealing device set up to prevent leakage between the pump shaft and the casing.
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Description
The function of shaft seals
Prevent high-pressure liquid from leaking out of the pump and prevent air from entering the pump. Although the position of the shaft seal in the pump is not significant, the normal operation of the pump is closely related to the shaft seal. If the shaft seal is improperly selected, not only does it require frequent maintenance during operation, resulting in the leakage of many transported liquids, but it may also cause fires, explosions, and poisoning accidents due to the leaked flammable, explosive, and toxic liquids, with unimaginable consequences. Therefore, it is necessary to choose a reasonable shaft seal structure to ensure the safe operation of the pump.
1. Due to the unequal pressure between the inside and outside atmosphere of the cylinder, steam or air outside the cylinder will inevitably leak out or enter along the radial gap between the main shaft and the cylinder, causing loss of working fluid, deteriorating the operating environment, and heating the journal or causing steam to enter the bearing chamber, causing deterioration of the oil quality. The air leakage also damages the vacuum, thereby increasing the extraction load. This will reduce the efficiency of the unit. Therefore, steam seals are installed at both ends of the rotor passing through the cylinder, This type of steam seal is called shaft end steam seal or shaft seal. The high-pressure shaft seal is used to prevent steam from leaking out of the cylinder, and the low-pressure shaft seal is used to prevent air from leaking into the cylinder.
2. During the operation of the steam turbine, a portion of the steam must inevitably leak into the atmosphere from the shaft end, causing loss of working fluid and heat, and also affecting the working environment of the steam turbine generator. If the adjustment is not appropriate and the leakage is too large, it will also increase the temperature of the bearings near the shaft seal or cause water to enter the bearing oil. For this reason, shaft seal heaters have been installed in various units to recover and utilize the shaft seal leakage of steam turbines
3. Prevent steam and valve stem leakage in the cylinder from leaking outward, polluting the environment of the turbine room and the lubricating oil quality of the bearings. Prevent high-temperature steam from flowing through the turbine shaft during normal operation of the unit, causing it to be heated and causing bearing overheating. Prevent air leakage into the vacuum part of the cylinder. Ensure the vacuum effect and degree of the condenser during unit startup. Recycle steam seals and valve stem leaks to reduce fluid and energy losses.
4. During the entire hot shutdown process where the turbine is tripped and the condenser needs to maintain vacuum, air leakage into the turbine is prevented, accelerating internal cooling of the turbine and causing bending of the main shaft.
