Special Operating Procedures For Use When Removing Plastic Residue - Techne IFB-201 Operator's Manual

Heater Cycle Time
High Cut Back
Low Cut Back
As the fluidised bath heats up the fluidisation will become more vigorous, due to the expansion of
the fluidising air. Units fitted with the automatic fluidising air control system will automatically
reduce the air input so as to keep a constant level of fluidisation. Manually operated units must
have fluidising air flow reduced until the level of fluidisation returns to its original state. The
following table indicates the flow rates that are factory set on an auto-air unit
Ambient to 200ºC
200ºC to 400ºC
400ºC to 600ºC
The fluidised bath should be operated with the bath lid fitted to reduce heat loss during the heat
up period, and to increase the efficiency of the fume extraction system. As the temperature of the
fluidised bath approaches the set point, the heater indicator, situated in the temperature controller
fascia, will cycle on and off, until the actual temperature reaches the set point temperature.
It may be desirable, depending on the process being carried out in the fluidised bath, to check the
actual bath temperature with an independent temperature sensor. Any offset in the temperature
may be corrected by adjustment of the temperature controller (an instruction manual for the
temperature controller is included with this manual). Further temperature checks may be made at
various points within the fluidised bath to ensure good temperature uniformity is being achieved
throughout the bed. Slight adjustment of the fluidising air flow rates will reduce any excessive
temperature gradients.
CAUTION: Care should be taken when handling hot parts which have been removed from a
fluidised bath. We recommend that protective clothing (gloves, aprons, and visors, etc) be worn at
all times when working with fluidised baths and that the installation and maintenance procedures
outlined in this booklet be followed explicate.

Special operating procedures for use when removing plastic residue

The industrial fluidised bath detailed in this manual is suitable for 'burning off' plastic residue from
plastic machine tools, and is effective on the full range of polymers. In addition, the bath is also
effective on rubber, epoxy resins and various paints. The bath provides a safe, dry, and fast
means of removing all plastic residues with the minimum effort.
The process is controlled at a uniform temperature so that distortion of tooling due to uneven
heating which occurs when using other heating methods is avoided. Furthermore, as the fluidised
bed is non-abrasive, physical damage to parts is minimal.
The cleaning process relies on heat being transferred from the fluidised bed to the immersed
tools, the heat degrading the plastic residue. Objects to be cleaned should be supported in a
basket or suitable holder for ease of handling and lowered into the fluidised bed.
To avoid physical damage and local overheating, it is important to ensure that any items placed in
the bed are supported and not allowed to rest either on the porous plate at the bottom of the bed
or against the wall of the inner container. The bath should be operated generally in the
temperature range of 450ºC to 500ºC, depending on the polymer to be removed. The process
time depends upon the thermal mass of the object, the amount and type of polymer to be
removed. During the first two thirds of the process time the polymer is reduced to a tar mix, in this
phase all the initially combustible products of the polymer are emitted from the fluidised bath in
the form of fumes that must be extracted and treated by suitable fume handling equipment.
HCT
HCB
LCB
220 l/min
180 l/min
150 l/min
25
0.3 sec
17ºC
17ºC
0.3 sec
62ºF
62ºF