Precautions for mechanical seals when inspecting hard ring surfaces1

Precautions for mechanical seals when inspecting the surface of the hard ring When the rectangle or ring becomes stiff, the amount of compression needs to be adjusted, otherwise it will heat up. (1) Thermal cracking; (2) The ceramic ring is broken; (3) notches; (4) The peeling off of the coating. Over-tightening of the ceramic ring is the main reason for cracking, and it is also a more common reason for the assembly of non-corrosion-resistant mechanical seals. Because the linear expansion rate of the coating material and the base material is different, when the temperature rises and the dyeing and finishing mechanical seal is high, cracks will appear on the surface of the ring, especially for Stellite alloys. Among the more advanced coating materials, cobalt-based tungsten carbide is inferior to nickel-based coatings. Cooling the sealing surface can effectively prevent thermal cracking. The solid particles remaining on the sealing surface often damage the surface. For example, the sand on the grinding wheel during grinding will damage the surface of the hard ring, resulting in the opening of the sealing surface or between the sealing surface. During the formation of crystals, and after regrinding the graphite ring, the abrasive will be embedded in the surface of the graphite ring. The failure of the rubber ring is related to the way of use. Usually, high pressure is one of the reasons for the failure of the pressed O-ring. When it is found that the O-ring becomes a rectangle or the ring becomes hard, the compression amount needs to be adjusted, otherwise it will heat up. Therefore, it is necessary to understand the use temperature of a synthetic rubber. The swelling of synthetic rubber rings is mostly caused by chemical erosion. They all have their own characteristics. For example, fluororubber can withstand higher temperatures, while ethylene and propylene ○-rings will swell when used in petroleum lubricating oil. Rubber has an erosive effect, so nitrile rubber products should not be installed in the motor, so high temperature and chemical corrosion are usually the main reasons for hardening and cracking of rubber products. Cuts and nicks on the rubber parts during installation are also common causes of seal failure. Old set screws on the shaft, keyways, splined shafts, sharp shoulders and other signs can damage the rubber parts.