In the centrifugal pumps the rotor, on which the impeller is
mounted, revolves in the stationary housing of the pump and there is minor gap
between the two. The centrifugal pump pumps a variety of fluids and sometimes these
fluids can be highly hazardous to the humans and environment.
The most effective method of preventing the leakage of the fluid
from the centrifugal pump to the external surroundings is
using the mechanical seals. The mechanical seals help sealing the rotating part
of the shaft against the stationary part of the pump housing. Thus the
mechanical seals are the devices that form the packing between the rotor and
the stationary part of the centrifugal pumps to prevent the leakage of the
fluid being pumped by the pump. There are two main parts of the mechanical
seals: one is the stationary part, which is connected to the pump housing and
the other is the rotating part which is connected to the rotating shaft.
Prior to the mechanical seals, the compression
packing like gland packing were used as the sealants though they are still
being used in number of applications. The mechanical seals are especially used
in the process applications where the centrifugal pumps handle hazardous
chemicals like HCL, sulfuric acid, etc. to meet the safety and the
environmental standards as per the federal regulations.