Parr Instrument A1120HC10 User Manual

A1120HC10 Magnetic Drive

Operating Instruction Manual

656M

Description

The A1120HC10 magnetic stirrer consists of a internal
rotor assembly with an inner set of magnets and an
outer coupling assembly with a second set of mag­nets. This assembly is intended for medium viscosity
applications and has a torque rating of 16 in-lbs (1.8
Nm).

The A1120HC10 magnetic stirrer can be used with
both the standard stirrer shaft and impeller(s) or
with a gas entrainment stirrer arrangement. It is
designed to stir at speeds up to approximately 2000
rpm. Maximum stirrer speeds are dependent upon
the viscosity of the vessel contents and the resultant
load on the motor.

This magnetic stirrer requires minimal maintenance;
however, it is important to protect these magnetic
stirrers from the heat in the reactor vessel. To pre­vent overheating each magnetic drive includes a
cooling sleeve. The cooling sleeve is held in place
on the housing with a snap ring and seals against
the housing with two O-rings. A steady fl ow of cold

water through this sleeve during all vessel operation
at temperatures above 80 ºC is required. Excessive

heating without use of the cooling water will also
damage the O-rings in the cooling sleeve.

Shaft Removal and Installation

To remove the stirrer shaft hold the A1147HC outer
housing of the magnetic drive assembly, and un­screw the stirrer shaft in a counter-clockwise rotation.
To install a replacement or alternate shaft, hold the
outer housing of the magnetic drive fi rmly and screw
in the new shaft.

*Note: It is important to hold the housing
securely when installing any of the stirrer
shafts so that the threads are fully engaged.

Magnetic Drive Maintenance

All rotating parts in Parr magnetic drives are self
lubricating and do not require servicing during nor­mal opera tions. It is advisable, however, to check the
drive from time to time for any evidence of leakage
into the con fi ned space between the inner and outer
rotors. This can be done without removing the drive
from the vessel head and does not require complete
disas sembly. To inspect the drive:

1. Remove the four socket head screws located near
the top of the outer housing and remove the top
cover from the housing. This will expose the plug
which aligns the inner rotor and carries the prin­ciple O-ring seal.

2. Unscrew the 1136HC2 plug, using a 264AC5 face
spanner inserted into the two holes at the top
of the plug while holding the rotor fi rmly with
a 264AC4 pin spanner inserted into one of the
holes at the bottom of the assembly above the
cooling sleeve. With the plug removed, the sleeve
bushing and thrust washer at the top of the rotor
will be exposed.

3. Check for any evidence of leakage past the O-ring
seal. If vapors from the reactor have produced
solid deposits in or around the rotor housing, the
deposits will have to be removed to keep them
from destroying the bushings or jamming the
rotor. If cleaning is not re quired, replace the plug
and close the drive.

4. If cleaning is required, the A1125HC inner ro tor
can be removed without removing the entire
drive from the bomb head. To remove: Unscrew
and remove the stir rer shaft from the underside
of the ves sel head. Then push the rotor upward
and out of the housing using the stirrer shaft
or other suitable rod inserted through the shaft
opening.

The inner rotor is a laser-welded, sealed unit which
should require no mainte nance, but it can be dam­aged by over heating as mentioned earlier.

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A1120HC10 Magnetic Drive

Bushing Removal

Remove the A1125HC inner rotor assembly from the
1135HC4 housing, the upper thrust washer 1132HC
sits on top of the inner rotor. The lower thrust
washer will be loose and also easily removed. Two
1133HC bushings are located in the 1135HC4 hous­ing. The third 1133HC bushing is located in the end
cap. A 1948HC bushing removal tool is recom­mended to remove these bushings.

Once the inner rotor, thrust washers and bushings
are removed, inspect the housing for any material
deposits that may have collected during operation.
When this unit is completely assembled, there is
about 5 ml of gas space surrounding the inner rotor
assembly. With some applications material may
condense in this area which would necessitate peri­odic cleaning to remove any build up of debris.

Parr Magnetic Drive

Bushing Installation

There are two 1133HC bushings required in the low­er portion of the 1135HC4 housing. A 1947HC bush­ing installation tool is recommended to install these
bushings. Install one bushing into the housing until
it stops against the lower shoulder of the housing.
The second bushing should be installed so that the
top of the bushing is .020” below the larger diam­eter area of the housing. The 1947HC installation
tool will accomplish this. This leaves a small internal
space between the two bushings in the housing.
Install the third 1133HC bushing in the end cap.

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 accidentally 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;
lubricate 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.

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Parr Instrument Company