TYPE MS8 - METAL BELLOWS SEAL
GENERAL APPLICATION INFORMATION
NTI type MS8
is an aircraft and marine precision - welded bellows seal designed
for extreme applications of speed, temperature and pressure, designed
for example: aircraft turbines, nuclear and submarine applications.
NTI seal materials used for the manufacture of metal bellows must
guarantee that the bellows will have the following characteristics:
workability, pressure resistance, temperature resistance, corrosion
resistance and reliability in service, The flexible element, which
must perform elastically under extreme conditions, must be particularly
corrosion resistant. Because of the think wall, the choice of
a suitable material is very important.
STANDARD
OPERATIONAL
CAPABILITIES
|
Pressure
Range-
|
0
to 150 P.S.I.
|
|
Temperature
Range-
|
-385°F
to +750°F
|
|
Speed
Range-
|
0
to 25,000 F.P.M. at seal face
|
MATERIALS
Generally, low expansion alloys are used in the various parts and AM 350 steel for the bellows. Face materials are chosen on the basis of the media to be sealed, shaft speed, and the mating face against which it is to be run. All materials will be recommended and a NTI seal control number assigned upon receipt of complete operating information.
MATING RINGS
Bellows seals
are generally applied in extreme environmental conditions and
the design of the mating ring is critical. To assure a successful
application, it is recommended that you order your mating rings
from NTI.
Important: Mounting and clamping of rings should not distort
the faces.
INSTALLATION AND HOUSING FITS
The extreme temperature conditions usually present when applying a bellows seal make the choice of materials and interference fits important. The normal method of assembly is to press the seal into the housing. Interference between seal and housing should range from .001" to .005" for all sized from ¼" to, and including 2" seals. All sizes from 2 ¼" to, and including 4" seals should have an interference from .002" to .007". Note: NTI seals O.D. is furnished with a finish of 30 microinches RMS. The housing I.D. should be provided with the same finish. A flanged bellows seal should also be considered for servicing your unit.