This article briefly discusses shaft seals, a type of friction seal or stuffing box used to prevent liquid leakage between the shaft and bearings of compressors or other fluid transport equipment. It also serves as a sealing device to prevent leakage between the pump shaft and housing. Common shaft seal types include packing seals, compressor shaft seals, and dynamic seals.

Reciprocating pumps typically use packing seals. When transporting media where leakage is not permissible, diaphragm reciprocating pumps can be used. Rotary pumps (including vane pumps and rotor pumps) mainly use packing seals, compressor shaft seals, and dynamic seals.

Packing seals are simple in structure, inexpensive, and easy to maintain. However, they have a high leakage rate and significant power loss. Therefore, packing seals are used for transporting general media, such as water; they are generally not suitable for petroleum and chemical media, especially not for valuable, explosive, or toxic media.

Compressor shaft seals offer excellent sealing performance, very low leakage, and long service life, but they are expensive, and their processing, installation, maintenance, and repair requirements are higher than those for general seals.