Each mechanical seal, only for the specified scope can be effective. Improper selection, will make the sealing performance significantly reduced, shortened life, and even failure. The main parameters of model selection are as follows:

I. medium pressure P of the sealing chamber

Medium lubricity is good, high viscosity, P≤ 0.8mpa choose non-equilibrium type. Medium lubricity is poor, low viscosity, P≥ 0.5mpa

II. Linear velocity V

V≤25m/s is of rotary type. V≥25m/s is a stationary type.

III. PV value

The PV value relates to the stability (vaporization) of the fluid film between the sealing surfaces and the wear resistance of the friction pair. Examples of PV limit values:

IV, sealing medium temperature T

In the absence of external cooling, the maximum temperature of the mechanical seal generally depends on the safe use temperature of the auxiliary sealing material. See the following table:

V, the particularity of the medium.

1, viscosity: low viscosity medium easy dry friction appropriate to choose the balance type. High viscosity medium, should use forced transmission structure.

2, corrosion and chemical solvents: a, strong corrosion should be sealed with external type of four fluorine bellows.

B. the applicable table of auxiliary seals in different chemical media is as follows

3. Containing suspended solid particles: tungsten carbide/tungsten carbide or silicon carbide/silicon carbide should be used for stationary and static ring materials. When the particles are easy to block the sealing chamber, washing liquid after filtration or separation by auxiliary device should be used to flush the end surface.

4, highly toxic or gas medium: it is appropriate to use double end mechanical seal.

Below Parts notes (translation): 1.static ring,2.dynamic ring, 3.press gland, 4.push ring, 5.spring, 6.positioning ring, 7.shaft sleeve, 8.seal ring for dynamic ring, 9.seal ring for static ring, 10.seal ring for shaft sleeve