Cause of leakage of mechanical seal, cause of leakage of mechanical seal of centrifugal pump
All kinds of centrifugal pump seal are adopted in most of the mechanical seal, mechanical seal is not a bad case of leak, than the old IS centrifugal pump with packing seal the liquid has obvious advantages of centrifugal pump mechanical seal leakage common usually has the following four:
(1) common periodic leakage
(1) the axial channeling of the rotor of the centrifugal pump is large, the auxiliary seal and the axle's interference amount are large, and the movable ring can not move flexibly on the axis. When the pump is turned over, the dynamic and static ring is worn and the compensation displacement can not be obtained.
Countermeasures: when assembling mechanical seals, axial axial momentum should be less than 0.1 millimeters. The interference between auxiliary seal and shaft is moderate. When radial sealing is ensured, the moving ring assembly ensures that it can move flexibly on the shaft.
The sealing surface of oil shortage caused by dry friction or galling seal.
Countermeasures: the height of lubricating oil surface in the oil cavity should be higher than that of the dynamic and static ring seal surface.
(2) leakage due to pressure
The leakage of mechanical seals caused by high pressure and pressure waves
Because the design of spring is much larger than that of pressure and total specific pressure, when the pressure of the sealing cavity exceeds 3Mpa, the sealing end will be larger than the pressure. The liquid film is difficult to form. The seal face is severely worn and the calorific value increases, resulting in the thermal deformation of the sealing surface.
Countermeasures: when assembling the mechanical seals of various centrifugal pumps, the compression of the spring must be carried out according to the regulations, not too large or too small. For mechanical seal under high pressure, measures should be taken. In order to make the end face force reasonable, cemented carbide and ceramic materials with high compressive strength can be used, and the lubrication measures of cooling should be strengthened.
The leakage of mechanical seal caused by the operation of vacuum state
In the process of starting and stopping the pump, the pump inlet is blocked, gas containing reasons such as pumping medium, may make the seal cavity negative pressure, thereby causing the sealing surface friction.
Countermeasures: double end mechanical seals, like IH chemical centrifugal pumps, will be used to improve the lubrication conditions and improve the sealing performance.
(3) leakage caused by medium
The particles and impurities in the medium enter the sealing surface to make the seal fail, and the auxiliary seal of the dynamic and static ring is corroded by weak acid and weak alkali in the medium, and the function is lost.
Countermeasures: to ensure the end cover, the oil chamber cleanliness of lubricating oil is not clean no match; mechanical seal oil chamber oil line should be higher than the sealing surface; according to the different media with different structure of mechanical seal, such as corrosive medium, rubber parts should be used in high temperature resistance, acid and alkali resistant fluorine rubber. Easy to enter in solid position with the tungsten carbide tungsten on alkali friction mechanical seal.
(4) leakage of mechanical seal caused by other problems
There are unreasonable places in mechanical seals such as design, selection, installation and so on
Countermeasure: the amount of spring compression error should be between -2 mm to 2 mm, is too large to increase the surface pressure, friction and excessive heat, easy to cause thermal deformation of the sealing surface and accelerate the end of Tang loss, is a small static ring face pressure is insufficient, cannot install seal; sealing ring gland sealing ring (or shell the face should be chamfered parts) and finishing assembly in order to avoid scratches, sealing ring.
- Close This Page
- Recommendation：
- Browse：
