External pressure type double end face gas film mechanical seal-

External pressure type double end face gas film mechanical seal

　2018-10-17　　

External pressure type double end gas film mechanical seal:

The external pressure double-end air film mechanical seal is formed by two sets of air film seals arranged back to back (face to face), and the structure is shown in Figure 4-12. 207 mechanical seal

Figure 4-12 External pressure type double end gas film mechanical seal

The two sets of seals are filled with clean isolation gas (usually nitrogen), whose pressure is about 0.2MPa higher than the pressure of the sealed medium in the mechanical seal chamber. In this way, a small part of the isolation gas that enters the sealed cavity enters the pump cavity through the inner sealed sealing surface to prevent the leakage of the sealed liquid, and most of the isolation gas enters the environment through the outer sealed sealing surface, and the isolation gas enters the environment. The sealed liquid medium does not touch, it is a clean isolation gas, which fully meets the requirements of environmental protection.

In order to prevent the opening of the inner seal due to the accidental interruption of the external supply of isolation gas, the inner seal adopts a double-balanced structure design, so that no matter the inner seal is subjected to a positive pressure difference (the pressure of the isolation gas is higher than the pressure of the sealed liquid) or a negative pressure difference ( The pressure of the isolation gas is lower than the pressure of the sealed liquid), and the inner seals are all balanced, which can achieve sealing. The hydrodynamic pressure grooves on the sealing surface of the inner seal and the outer seal static ring (or moving ring) are engraved on the outside of the sealing surface. This kind of gas film seal is mainly suitable for all kinds of media without solid particles to ensure that the sealed process liquid medium achieves 'zero leakage' or 'zero escape.' 　　964.html,

The structure of the air film mechanical seal for pumps 　　 internal pressure type double end air film mechanical seal structure