Mechanical Pump Oils
F16
Scientific Instrument Services, Inc.
TM
Phone: 908-788-5550
www.sisweb.com/catalog/08/F16
W
henever selecting mechanical pump fluids for use in
mass spectrometers, it is important to select the fluid
with the lowest vapor pressure. The vapor pressure of
the oil is important because it determines the ultimate vacuum the
pump can achieve. Lower vapor pressures will allow the user to
minimize backstreaming, significantly reduce pumpdown time and
maximize vacuum. The major mineral based oils used for rough
pumps in mass spectrometers include Inland 19, Invoil
®
20, Inland
33 and Inland 45. Any of these pump fluids can be used in all BOC
Edwards, Alcatel, Welch and other mechanical rough pumps.
Inland 19
Invoil 20
Inland 33
Inland 45
Inland TW Fomblin YO6/6
Vapor
Pressure
3 x 10
-5
3 x 10
-6
1 x 10
-6
1 x 10
-7
1 x 10
-6
3 x 10
-6
(torr)
The selection of a specific grade of pump oil utilized depends
on the users needs including the mass range of the mass
spectrometer, the system cleanliness required, the sensitivity
required and the cost the user is willing to pay.
Inland 19
is the basic mineral oil used in most mass spectrom-
eter vacuum pumps. It has been engineered for use with all
mechanical vacuum pumps, providing for minimal backstreaming.
Invoil 20
is a better grade of mineral oil for use in mechanical
rough pumps. It has been distilled to remove the majority of the light
fractions present in the base oil. These light fractions represent
weak links in oil and tend to provide a source of attack for reactive
gases. In addition they can easily migrate into the vacuum system
to increase mass spec background. Invoil 20 will provide for better
pumping efficiency, lower vacuum and longer vacuum pump life in
comparison to Inland 19 or similar oils.
Inland 33
is manufactured to enhance the oxidation resistance
of the fluid providing outstanding chemical stability. The process
also provides a clear oil base virtually free of impurities.
Inland 45
is the newest and best grade of oil for mechanical
vacuum pumps for mass spectrometers. It is a highly refined and
distilled pump oil which will provide for optimum vacuum levels and
minimal mass spectrometer background. It is recommended for
mass spectrometers such as high resolution instruments which
require the cleanest system, highest vacuum levels and optimum
pumping efficiency. This oil is now recommended for the Agilent
mass spectrometer systems.
Inland TW
mechanical pump fluid is specifically recommended
for applications where exposure to reactive or corrosive gases is
prevalent, such as electrospray and particle beam.
Fomblin PFPE
oils are non-flammable chemically inert fluids
for use in areas where there are high levels of oxygen or where
serious corrosion is a problem. This oil is identical to Krytox.
Several manufacturers recommend this pump fluid for uses such as
in the Agilent Particle Beam mass spectrometer.
Selection of Oils for Mechanical Rough Pumps
Vapor
Boiling
Pressure
Point
Viscosity
Pour
Flash
Fire
Density
@25°C
@.01 Torr
@40°C
@100°C
Point
Point
Point
@25°C
Product
(Torr)
(°C)
(CST)
(°C)
(°C)
(°C)
(gm/cc)
Reclaimable
Inland 19
3 x 10
-5
112
51
8.1
-15
213
244
Invoil 20
3 x 10
-6
127
58
8.5
-10
224
259
Invoil 21
112
54
8.1
-15
213
244
Inland 45
1 x 10
-6
133
49
6.9
-59
268
288
0.83
Yes
Inland 77
1 x 10
-4
138
90
9.9
-9
257
291
0.87
No
Inland TW
<1 x 10
-6
158
-12
243
270
Inland HVTW
<1 x 10
-6
161
105.9
12.9
-12
249
277
0.86
Yes
Fomblin
6 x 10
-6
>250
22
4
-45
None
None
1.88
Yes
Y06/6
Fomblin
3 x 10
-6
>250
47
7.5
-40
None
None
1.89
Yes
Y14/6
Fomblin
3 x 10
-6
>250
54
None
None
1.89
Yes
Y16/6
Fomblin
1 x 10
-6
>250
72.4
10
-35
None
None
1.89
Yes
Y25/6
Inland FF-10
1 x 10
-4
----
28.8
4.5
----
199
221
0.85
No
Inland 33
<1 x 10
-6
166
67
9.3
-10
247
275
0.86
Yes
3 x 10
-5
56
8.9
8.6
-45
0.86
No
0.86
Yes
0.86
Yes
0.86
No
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