Parr Instrument Magnetic Drive - Manual (Page 5)

Parr Magnetic Drives
w w w . p a r r i n s t . c o m 5
Disassemble the Outer Drive
1. Remove the four socket head screws located near
the top of the outer housing; then lift the cover
from the housing to expose the upper snap ring.
Peel the snap ring out of its groove with a small
screwdriver; slide it upward and remove it.
2. Take a firm grip on the outer drive housing and
pull it upward to separate the outer assembly from
the magnetic drive housing. The lower bearing may
not come out with the housing. If not, remove at
this time.
Reassemble the Outer Drive
1. Slide the lower spiral snap ring back into its
groove; then slide the lower ball bearing onto the
inner hous ing. The inner magnets should hold the
bearing at the middle of the housing.
2. Slide the outer drive assembly over the rotor,
thereby pushing the lower bearing down against
the lower spiral snap ring. Hold both parts firmly
during this step so that the magnets do not slam
the outer drive into place.
3. Insert the upper wave spring into its groove in
the outer drive housing and slide the ball bearing
into place against the wave spring, then anchor
the bearing by pushing the retaining snap ring
downward until it snaps into its groove above the
bearing. During this step sufficient pressure must
be applied against the snap ring and force the
wave spring downward and allow the snap ring to
drop bearing to force the wave spring down ward
and allow the snap ring to drop into its groove. This
can be done with a pair of screw drivers, using
alternating pressure on the snap ring. This must be
done carefully to be sure that the screw drivers do
not slip and damage the seals in the bearings. To
simplify the opera tion, Parr offers a magnetic drive
assem bly tool (Part No. 2086HC) consisting of a
properly sized cup which can be pushed downward
against the snap ring to force it into its groove.
There are cups on the 2086HC assembly tool to fit
both the small and larger Parr magnetic drives.
4. Replace the top cover and secure it with the four
socket head screws.
When replacing the bushings in the magnetic drive
housing, slide the parts into place carefully and be sure
to separate the two lower bushings with a spacer. A
specially designed bushing insertion tool is available
for this operation (See Page 8). Using the insertion tool,
slide a bushing onto the end of the tool with the longest
shank, then insert the tool with the bushing into the
opening in the rotor chamber and push it down until the
shoulder on the tool strikes the bottom of the chamber.
This will position the bushing properly. Then drop the
spacer into the opening and use the short end of the
installation tool to insert the upper sleeve bushing,
again pushing the tool downward until it strikes the
bottom of the plug. When properly installed, the top of
the upper bushing should be flush with the bottom of
the rotor chamber.
After cleaning the rotor and the chamber, install the
inner rotor as follows:
1. Set the lower thrust washer into posi tion so that it
will be available to cushion the rotor if it should ac-
cidentally slam into the bottom of the chamber.
2. Lower the rotor into the chamber slowly, but be
prepared to resist the strong pull of the outer
magnets during this operation. Use the same rod
employed when removing the rotor to resist the
strong pull during assembly.
3. Replace the upper sleeve bushing and the O-ring
in the top plug; insert the upper thrust washer; lu-
bricate the threads with 424HC2 anti-seize lubricant
(careful not to get any on the O-ring) and screw the
top plug into place. Then replace the top cover and
secure it with the four socket head screws.
The O-Ring Seal
The O-ring, which seals the top plug in Parr magnetic
drives, is made of PTFE. If solvent attack becomes a
problem, the O-ring may have to be replaced with an
O-ring made of another material.
Servicing the Outer Drive
The outer drive is supported by two high quality sealed
ball bearings which do not require lubrication. Any oil
leak or noise from the bearing will indicate that the
seal or the bearing has failed and the bearing must be
replaced.