SEAL: PURPOSE:
— Prevent
leakage of fluid from a closed container/system to atmosphere.
— Prevent
leakage of air from atmosphere to inside of the container/system.
— Prevent
contamination.
— Maintain
pressure inside the system.
CLASSIFICATION OF SEALS:
Seals are classified in two ways:
•
Static seals:
It is used when there is no relative motion between two parts to be sealed.
•
Dynamic seals:
It is used when there is some relative motion between two parts to be sealed.
STATIC SEALS (GASKETS):
•
A gasket is a packing designed to go
between two rigid parts in stationary relationship.
•
Gaskets are positioned between the joint
faces and then they are tightened enough.
•
The gasket material must flow into the
hills and valleys of the joint face and make a tight seal with no pathways for
leakage.
•
The gasket must be able to maintain this
seal under all the operating conditions of the system including extremes of
temperature and pressure.
