For a better sealing and reliable performance, all GN centrifugal pump utilize mechanical seal.
It is one of the most important parts for centrifugal pump. Cost of mechanical seal is much more higher the common sealing material.
For saving cost, many Chinese company used packing for sealing the centrifugal pump. It is easier for mud leak with the packings.
Common material for packing are 2 kinds:
1) Asbestos packing: In many European countries, asbestos is forbidden as bad to human health
2) Aramid fiber packing: it is also a kind of chemical material, and but good for sealing