24
5. Handling precautions
About applicable organic solvents
This unit has been designed to use isopropyl alcohol and ethanol. Note that the following restrictions
shall apply when other organic solvents are used.
(1) Restrictions because of explosion limit oxygen concentration
When N
2
gas, organic solvents, and air (oxygen) are mixed, explosion will occur when the
oxygen concentration is over the oxygen concentration limit and if there is an ignition source.
This means that it is desirable the oxygen concentration limit of a solvent is as high as possible.
The oxygen concentration limit for this unit is 9
％
. Do not use any organic solvent whose oxygen
concentration limit is below 9
％
.
（
See “Oxygen concentration limit table” on P.25. Also, calculate
limits for organic solvents not shown in the table using the “calculation method of concentration
limits”.
(2) Restrictions because of the boiling point
Although the unit recovers solvent by cooling it in the condenser (cooling trap), the outlet
temperature of the condenser (TRAP TEMP MONITOR) may become considerably high
depending on the outlet temperature, amount of liquid that is sent, environmental temperature, or
duration of sending liquid.
〔
Example
〕
Environmental temperature: 35
℃
Amount of liquid to send: 2000mL/H
（
ethanol
）
Air amount: 0.5m
3
/min
Liquid sending time: 30 min
Outlet temperature: 100
℃
Condenser outlet temperature: 37
℃
Thus a solvent with a lower boiling point may not be condensed efficiently. (See “Table of oxygen
concentration limit” on P.25.) In fact, you do not need to set inlet and outlet temperature higher
when you use a solvent with a low boiling point. For example, you can operate the unit with lower
condenser outlet temperature by reducing the air amount and amount of liquid to send for
solvents with a low boiling point such as methylene chloride.
〔
Example
〕
Environmental temperature: 25
℃
Amount of liquid to send:1170mL/H
（
methylene chloride
）
Air amount: 0.45m
3
/min
Liquid sending time:20 min
Outlet temperature: 38
℃
Condenser outlet temperature:14
℃
(3) Restrictions because of boiling points
When the solvent contains an organic solvent with a high melting point or water, too low trap
temperature might cause it condensate in the condenser. In such a case, raise the trap
temperature by increasing air amount, increasing the inlet temperature, or increasing the amount
of liquid to send, or stop the freezer once with DEFROST switch and allow condensed solvent or
water to solve. (When the trap temperature is lower than the melting point before sending solvent,
watch the trap temperature a while because that temperature will rise once sending of solvent is
started.)
When you use a water soluble solvent, try to disconnect this unit and operate with ADL311S or
GB210A only.
(4) Restrictions because of corrosion resistance
This unit has been designed to use isopropyl alcohol and ethanol. When other solvents are used,
care must be taken because service lives will differ from part to part. See the table of corrosion
resistance on P.26 and the piping system drawing that shows parts made of materials other than
stainless steel or glass on P.27. In terms of this unit, components other than the liquid sending
tube are exposed to thin solvent steam only and will not immediately corrode even if they are
exposed to chemicals marked with
△
or × in the corrosion resistance table, if any abnormalities
such as abnormal increase speed of oxygen concentration or a gas leakage in the pipe path,
replace defective parts immediately because service life of some parts may be shortened due to
solvents other than ethanol and isopropyl alcohol.
