1. Tungsten carbide dynamic ring
   
2. Silicon carbide stationary ring
   
3. Chrome steel dynamic ring
   
4. Carbon stationary ring
   
5. Perfluoroelastomer O-ring
   
6. VitonÆ O-ring
   
7. PTFE backup ring
   
8. Compression spring
   
9. Integral pump
   
10. Media excluder ring
    
    

Mechanical Seal

The function of the mechanical seal is to separate the rotating agitator shaft, the material being processed and the bearings. The pressurized double-acting mechanical seal accomplishes this with two sets of highly polished seal faces constructed of quality materials. On the process side, NETZSCH utilizes tungsten carbide and silicon carbide. These materials have been selected for their abrasion resistance. The seal face materials on the atmospheric side are chrome steel and carbon. The tungsten carbide and the chrome face rotate with the agitator while the silicon carbide and carbon ring are held stationary in the seal housing. This sliding action between the seal faces creates the sealing surfaces.

Seal Reservoir

A seal fluid provides lubrication to the seal faces and acts as a cooling medium, increasing the life of NETZSCH seals. The seal fluid circulates from the mechanical seal to the seal reservoir where it is cooled and returned to the seal. An integral pump located in the mechanical seal provides the circulation, eliminating the need for an external seal fluid pump. A thin film of seal fluid between the seal faces provides a continuous rinsing action. Any fluid compatible with the material processed can be used.

Seal Protection Switches

NETZSCH mechanical seals are protected by three standard seal protection switches. A pressure switch on the process feed piping protects the seal from high process pressure. Similarly, an air pressure switch located on the seal reservoir monitors constant seal pressure. A liquid level switch monitors seal fluid level to ensure that the seal operates with lubrication and cooling. The seal protection switches are engineered to increase the service life of the mechanical seal and the mill.