The shaft seal  of the rotary pump (including vane pump, rotor pump and so on) has packing seal, mechanical seal and dynamic seal.
    1 packing seal
    Packing seal has the advantages of simple structure, cheap price, convenient maintenance, but the leakage is large and large power loses. So the packing seal is generally used for conveying media, such as water; It generally does not apply in petroleum and chemical medium, it can’t be used in expensive, explosive and toxic medium in particular.
    2 mechanical seal
    The sealing effect of the mechanical seals (also known as end face seal) is good, the amount of leakage is small and long life, but the price is expensive. The processing and installation of maintenance than the general requirements of high seal.
    Mechanical seal for transporting oil and chemical medium. It can be used for various viscosity, strong corrosive and containing particles of the medium. American Petroleum Institute API 610 standard (8th Edition) provides: in addition to the user specified shall equipment container type mechanical seal.
    3 dynamic seal
    Dynamic seal can be divided into two types: the back seal and the auxiliary impeller seal.