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5. Handling Precautions
Drying method under proper condition
（１）
Different drying sample ask for different drying condition. Spray drying method is not
workable for all samples. Normally, this method is not applicable for the substance with
thermo plasticity (such as low melting, thermo softening substance: sugar, fat etc.).
Therefore, when using this unit for drying these substances, its recovery rate will be
significantly lower.
（２）
Spray drying method is very suitable for some substance. After drying, there is almost no
powder attached on the blower. As to the reason why there are always some powder
attached on the blower, besides the above mentioned characteristics of the substances,
the reason is that the solvent can not be evaporated. Increase the heat can reduce the
water in the powder. So this problem can be solved by increase the inlet temperature or
increase the flow of dry air, also it can improved by reduce the sample delivery volume. If
the problem is caused by the substance itself, it can be adjusted by adding some special
additive to the sample.
（３）
If the powder attachment phenomenon is very serious in the drying chamber, generally it is
caused by the following reason: sample concentration too high; inlet temperature too low;
sample delivery quantity too high; Spray air pressure too high or too low etc. After drying,
70-85% of samples will be recycled to the product catcher, the remaining 15-30% samples
will be attached to the drying chamber. If there are serious problems on the chamber,
please adjust following the above instructions.
（４）
If the hygroscopicity of the sample is high, it will leave wet powder inside the product
catcher. In this case you can follow the instruction in (2) to improve its drying condition,
and can increase the temperature to operate for the product catcher.
（５）
After drying, there are some small particles (under
μ
) which can not be caught by the
blower; these powders will be discharged outside. If the powder is too much, please lower
the dry air flow or decrease spray air pressure to solve the problem. The lower the sample
concentration, the small the particle diameter is. The sample concentrations can be
adjusted when necessary.
（６）
During operation, when the sample attached to the head of the spray nozzle, the spray
direction may change. In this case, please turn on the NOZZLE BLOW switch, use
compressed air to blow away the attachments on the nozzle head. If dirtiness still exists,
disassemble the nozzle; wipe the nozzle head with wet tissue.
（７）
Some samples will cause static electricity on the blower. In this case, remove the static
electricity by applying proper methods. Sometimes you can install wires on the glass to
connect to the ground. If this still can not solve the problem, you can remove the static
electricity and direct contacts the cyclone.