Tungsten Carbide Mechanical Seals

Tungsten carbide mechanical seals are being used increasingly on fluid pump to replace packed gland and lip seal. tungsten carbide mechanical seal Pump with mechanical seal perform more efficiently and generally perform more reliably for extended periods of time.

According to the shape, those seals are also called tungsten carbide mechanical seal rings. Due to the superiorities of tungsten carbide material, tungsten carbide mechanical seal rings shows high hardness, and the most important is that they resist corrosion and abrasion well. therefore, tungsten carbide mechanical seal rings are having wider use than seals of other materials.

Tungsten carbide mechanical seal is provided to prevent pumped fluid from leaking out along the drive shaft. The controlled leakage path is between two flat surfaces associated with the rotating shaft and the housing respectively. The leakage path gap varies as the faces are subjected to varying external load which tend to move the faces relative to each other.

The products require a different shaft housing design arrangement compared to that for the other type of mechanical seal because the mechanical seal is a more complicated arrangement and mechanical seal does not provide any support to the shaft.

Tungsten carbide mechanical seal rings come in two primary types:
Cobalt bound (Ammonia applications should be avoided)
Nickel bound (May be used in Ammonia)
Typically 6% binder materials are used in tungsten carbide mechanical seal rings, although a wide range is available. Nickel-bonded tungsten carbide mechanical seal rings are more prevalent in the wastewater pump market due to their improved corrosion resistance compared with cobalt bound materials.

In order for the tungsten carbide mechanical seal to perform over an extended time period with low frictional the mechanical seal faces are generally hydrodynamically lubricated. The fluid film will need to carry substantial load. If the load becomes to high for the film surface contact will take place with consequent bearing failure. This lubricating film is generally of the order of 3 micrometres thick , or less. This thickness is critical to the required sealing function. Tungsten carbide mechanical seal often have one face of a suitable solid lubricant such that the mechanical seal can still operate for a period without the fluid film.