In the operation of precisionmechanical parts processing manufactures, mechanical seals are widely used in CNC parts processing equipment. When a mechanically sealed part fails, the part must be replaced or the machining accuracy of the part must be improved. In rthe mechanical sealing process, improving the machining accuracy of other components is very beneficial to the effect of the mechanical seal. The sealing effect depends on the smoothness and unevenness of the friction surface of the static and dynamic ring. The width of the friction surface of the static and dynamic ring is generally between 2 and 7 mm. Generally, there are four improvement measures:
1. Mechanical seal vibration and heat treatment: Firstly, whether the clearance between the static ring and the seal cavity is small, it is better to increase the inner diameter of the seal cavity or reduce the outer diameter of the rotation, at least to ensure a clearance of 0.75 mm. When the friction pair is improperly paired, it is necessary to change the dynamic ring material to make it resistant to temperature and corrosion. This will reduce the vibration and heat of the mechanical seal.
2, the treatment of mechanical seal leakage: the general leakage is caused by a variety of reasons, must find a specific cause. In order to minimize the leakage of the mechanical seal, it must be assembled in strict accordance with the technical requirements, while also paying attention to other effects.
(1) The assembly should be clean and clean. Mechanically sealed parts, tools, lubricants, and wiping materials should be very clean. The sealing end face of the static and dynamic ring should be wiped with a soft gauze.
(2) Trimming the chamfer and rounding. The chamfers such as the shaft and the sealing end cover should be smoothed, and the rounded corners of the shaft and the end cover should be sanded and polished.
(3) When assembling the auxiliary sealing ring, the auxiliary sealing ring should not be soaked and washed with gasoline or kerosene to avoid swelling and premature aging. After the static and dynamic ring is assembled, press the compensation ring by hand to check whether it is in place and whether it is flexible; whether the elastic opening ring is positioned reliably. After the moving ring is installed, it must be ensured that it moves axially on the shaft.
3, the pump shaft is large amount of treatment: to eliminate the axial volume, it is necessary to rationally design the axial force balance device. For multistage centrifugal pumps, add axial thrust bearings to the balance plate. The axial force is balanced by the balance disc, and the axial direction of the pump shaft is limited by the axial thrust bearing.
4. Add auxiliary flushing system: The sealing medium containing particles and impurities in the sealed cavity must be washed. Otherwise, the mechanical seal spring will fail due to the precipitation of crystals or the deposition of particles and impurities. If the particles enter the friction pair, it can cause rapid damage to the mechanical seal. The auxiliary flushing system can effectively protect the sealing surface and cool, lubricate, and wash away debris.
The above briefly introduces the application of mechanical seals on rotating equipment. Later, when encountering the problem of mechanical seal failure, we must first analyze the cause of mechanical seal quality accidents, considering the influencing factors of the mechanical seal itself, and also considering the external mechanical seal. Some of the influencing factors, take measures to continuously improve the mechanical seal effect of mechanical parts processing.
