ADVANCED SEALING TECHNOLOGY
INSTALLATION INSTRUCTIONS
AST 40 BEARING ISOLATOR
PREPARATION
1. Disassemble the equipment so that the seal can be
installed over the end of the shaft. Clean the seal
cavity.
2. Remove all sharp edges and burrs from the shaft
especially where the O-ring will slide. Cover threads
and keyway slots with thin tape to prevent cutting the
O-ring.
3. The shaft finish must be smooth, free from nicks and
grooves. It should feel smooth when you run your
fingernail along the shaft (32-63 microinch Ra).
4. The shaft diameter must be .001/-.003 inch of
the nominal shaft size.
5. The shaft must run true in the area where the seal is
installed. No more than .001 inch of runout per inch
of shaft diameter is acceptable. Use a dial indicator
to measure runout.
6. Bearing end play must not exceed .010". Excessive
end play or shaft runout will shorten seal life. Check
with a dial indicator.
INSTALLATION
1. The bearing isolator has three parts: the seal case,
the magnet, and the insulator (Figure 1). The seal
case is the rotating part of the seal, including the
carbon, and has an O-ring on its inside diameter.
The magnet has one lapped face and one unlapped
face. The insulator adapts the magnet to fit the
equipment housing bore and acts as a magnetic
insulator between the magnet and the housing.
2. Disassemble the seal by pulling the seal case straight
back from the magnet. Sliding the seal case across
the magnet will damage the carbon.
3. If the magnet is separate from the insulator, lubricate
the magnet O-ring and the outside diameter of the
magnet with the fluid provided. Install the magnet O-
ring into the insulator. Cover the highly polished
lapped surface of the magnet with a lint-free wiper
and press the magnet into the insulator by hand until
the magnet is squarely seated.
Hammering the
magnet will break it.
4. Press the insulator into the equipment housing using
an installer made of aluminum, brass, wood, or plastic
(Figure 2). Press on the insulator only, not the
magnet. Use a dial indicator to check squareness of
the insulator to the shaft.
5. Without touching the carbon face, remove the O-ring
from the seal case and lubricate it with the fluid
supplied with the seal. Reinstall the O-ring.
6. Completely lubricate the shaft where the O-ring will
slide with a small amount of the same fluid.
7. Slide the seal case along the shaft and into contact
with the magnet (Figure 3). Push the O-ring which
contacts the shaft toward the carbon using an
installer (Figure 4) or thin plastic shim.
NOTE
The seal installer should be familiar with the installation
of mechanical seals and with the plant safety
requirements. If you are in doubt about any phase of
installing this mechanical seal, stop the installation and
get assistance. The decision to use any AST mechanical
seal in a particular service is the customer's
responsibility.
7/12/05
ADVANCED SEALING TECHNOLOGY, 250 North Street A-11, Danvers MA 01923 USA (978) 750-8001 Fax: (978) 750-6980
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