Mechanical seal for kettle Precautions when inspecting the hard ring surface

The failure of rubber ring is related to the use mode. Usually, high pressure is one of the reasons for the failure of imported pressed O-ring. When it is found that the O-ring becomes rectangular or the ring becomes hard, the compression amount needs to be adjusted, otherwise it will generate heat.

(1) Hot cracking;

(2) Ceramic ring fracture;

(3) Nick;

(4) The coating falls off.

Tight assembly of ceramic ring is the main reason for fracture, and non corrosion resistance of assembly is also a common reason.

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 ring surface, especially Stellite alloy. Cobalt based tungsten carbide is not as good as nickel based coating in higher coating materials. Cooling the sealing surface can effectively prevent hot cracking. The solid particles left on the sealing surface often damage the surface. For example, the sand particles on the grinding wheel will damage the hard ring surface during grinding, causing the sealing surface to open or generate crystals between the sealing surfaces. After regrinding the graphite ring, the abrasive will be embedded in the surface of the graphite ring.

The failure of rubber ring is related to the use mode. Usually, high pressure is one of the reasons for the failure of pressed O-ring. When it is found that the O-ring becomes rectangular or the ring becomes hard, the compression amount needs to be adjusted, otherwise it will generate heat.

Therefore, it is necessary to know the service temperature of a synthetic rubber. The swelling of synthetic rubber rings is mostly caused by chemical erosion, and they all have their own characteristics. For example, fluororubber is resistant to high temperature, while ethylene and propylene O-ring will swell when used in petroleum lubricating oil, and ozone will erode NBR. Therefore, NBR products should not be installed in the motor, so high temperature and chemical corrosion usually cause rubber products to harden Main causes of cracks.