380
16.
VACUUM TECHNIQUE
changing the pressure
at C, the gas in ] can be brought to the
exact pressure
desired and sealed or at the constriction.
16—22.
Cleaning Processes—Rubber
tubing should
be
washed with a solution of caustic potash (sodium hydroxide,
_
NaOH), then carefully washed in distilled water and dried.
'
Air\
:-f
'-‘=---.‘.
…
A
FIG. 16—14.
Cleaning mercury.
For cleaning glassware, a saturated solution of potassium
bichromate in sulphuric acid is used. This is much more effective
'
if used hot. When cleaned, the glass should be carefully washed
in distilled water and dried by drawing warm dry air through it.
A very simple and effective way of cleaning mercury is shown
F
TË…ËËÎ
ColdAir
,
Cold
'
%
B
'?…f
o
4.;__;1
12,3
.
.
ië‘{
A
-
x!“
aggl
‘
l*—Î_ïÎ
_
‘
_
Êf
.
ë
._
_
.
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î—E53
_m‘
Laï—
-
.
_
.
,
_
F1G-16—15- Cleaning
-
FIG.16—16.
Distilling—‘memury.
__
' _
_
'
'
mercury.
,
,
'
'
f
_.
*
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