Mechanical seals in the use of the process, if the use of a long time is easy to use overheating, in this regard, the next to its impact on the use of equipment overheating to understand, in order to better use equipment.
According to the different working conditions and the nature of the medium, there are high temperature resistance, low temperature resistance seals, high pressure resistance, corrosion resistance seals, particle medium seals and seals adapted to the light hydrocarbon medium that is easy to vaporize, etc., should be selected according to different structural types and materials of seals.
There is a gap in one or two end faces, which indicates that the distance between the two end faces is too large, and when the two end faces are forcibly closed, there will be a gap. The common cause of end separation is the sudden evaporation of the inlet seal medium. For example, water, especially in hot water systems or liquids containing condensed water, expands as it evaporates, thus separating the two ends. The cavitation phenomenon of the pump coupled with the blockage of the seal may also be the cause of the notch on the end face of the seal. In this case, it is not due to vibration and the coupling is not caused by this, because it is not enough to make the end face notch.
Reducing the temperature of the end face is a common method to prevent the damage of the end face caused by the rapid evaporation of the medium. At the same time, the use of good thermal conductivity material group is also advantageous, such as the use of nickel-based cemented carbide and copper impregnated graphite group, in addition, the use of balanced mechanical seals, or the use of special corrosion resistant seal gland from the external injection of liquid cooling, or direct cooling of the cavity seal, etc., to reduce the temperature of the seal end face is very effective.
For failed seals, the end faces of friction pairs often leave very fine radial cracks, or radial cracks with blister marks, or even cracks. This is caused by the overheating of the seal, especially the ceramic and cemented carbide sealing surface is easy to produce such damage. Poor lubricity of the medium, overload, high operating temperature, high linear speed, improper combination of paired materials, etc., any one of these factors, or the superposition of several factors, can produce too much friction heat, if the friction heat can not be distributed in time, it will produce thermal cracks in the dyeing and finishing mechanical seal, resulting in excessive wear and high leakage.
To solve the problem of sealing overheating, in addition to changing the end area and reducing the load, it can also be solved by using a static seal and adding a guide jacket to force cooling the circulating fluid guide sealing surface, or opening a fluid power groove on the seal end face. There are many small heat spots and isolated discoloration areas on the friction end face, which indicates that the seal is deformed and distorted under the influence of high pressure and heat. For the thermal deformation of the end face, the general calculation method is not allowed, and the finite element method should be used to calculate in order to improve the design of the seal ring.