The controlled clearance seal is also commonly called a floating labyrinth seal. The design principle of the seal is to have a precise control of clearance between the rotating shaft and the inside diameter of the seal ring. In operation, under ideal conditions, there is a pressure differential across the seal with the air side pressure being higher than the oil side. This differential prevents oil leakage and holds the carbon sealing ring against the oil side mating ring while the shaft turns freely within the sealing ring.


APPLICATIONS

Controlled clearance seals provide reliable shaft sealing where temperatures, speeds and limited lubrication prohibit the use of conventional face type seals. This is excellent for sealing gases at cryogenic or hot temperatures. The small compact design allows the use
of this seal in centrifugal compressors, gas turbines and other high speed applications.


CONSTRUCTION:

2. METAL RETAINING BAND: A compression fit with the carbon has two
functions: provide tensile strength and to control the thermal expansion of the metal/carbon composite to closely match that of the rotating shaft to obtain a controlled clearance.

3. OUTER SHELL OR HOUSING: The metal housing provides a mating face for the carbon or a separate mating face can be used.

4. SPRING: Usually a wave spring holds the carbon against the mating face during start-up and shut down and allows for a small reverse pressure. Normal positive operating pressure holds the carbon in place.

ADVANTAGES

Small Compact Size
· Rugged
· Long Life
· Low Heat
· Seal-Centering, Self-Aligning
· No Elastomeric Parts
· High and Low Temperature Capabilities
· High Speed Capabilities
· Unlimited Axial Shaft Movement