16—3.
PUMPS REQUIRING A FORE VACUUM 359
_
Inst2ead
of mercury, certain
cils1 may be used in diffusion
pumps.
These speaal 0113 have a very low vapor pressure at
room temperature so that liquid air or C02 traps are not needed.
/
,
_
H
,
<"
'
.
.
C3
_
,
Cz
,
F
—
"
c.
"(\
.
a
_
A
:
«.
E
.
"
_;'\%—‘°._—, :‘_____:°
.
'
.
_
,
f
FiG. 16—6. A çompaet three—stage
_
-
?
A_two-stagemetal system is
The annu1ar
*_
area at the jet _(C) between the umbr€Ha and the main (outer)
_
wall Will
”range of pressures over which the pump
-
is most effective, This gap 'i—s small_in
the rst stage (annuleir
PUMPS REQUIRING A FORE VACUUM 359
_
Inst2ead
of mercury, certain
cils1 may be used in diffusion
pumps.
These speaal 0113 have a very low vapor pressure at
room temperature so that liquid air or C02 traps are not needed.
/
,
_
H
,
<"
'
.
.
C3
_
,
Cz
,
F
—
"
c.
"(\
.
a
_
A
:
«.
E
.
"
_;'\%—‘°._—, :‘_____:°
.
'
.
_
,
f
FiG. 16—6. A çompaet three—stage
_
-
?
A_two-stagemetal system is
The annu1ar
*_
area at the jet _(C) between the umbr€Ha and the main (outer)
_
wall Will
”range of pressures over which the pump
-
is most effective, This gap 'i—s small_in
the rst stage (annuleir