Vacuum Pumps

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Vacuum Pumps
Basics
• vac·u·um
– noun 1. a space entirely devoid of matter.
– 2. an enclosed space from which matter, especially air, has been partially removed so
that the matter or gas remaining in the space exerts less pressure than the atmosphere (
opposed to plenum). (dictionary.com)
• Exhaust pressure= atm generally
• Base pressure = pressure pump gets down to
• Compression ratio = exhaust/base= big
number
• Boyles Law P1V1=P2V2
History of vacuum pumps
• Suction pumps go way back
(Romans, Byzantine empire, etc)
• Major improvements on the idea of
vacuum made by Galileo,
Evangeilist Torricelli, and Blaise
Pascal
• Otto von Guericke made first pump
and famous for Magdeburg
hemispheres experiment
Types of Vacuum pumps
• Positive displacement pumps
– Expand a cavity, seal, exhaust, repeat
• Momentum transfer pumps
(molecular pumps)
– High speed liquids or blades to knock
gasses around
• Entrapment
– Create solids or adsorbed gases
(cryopumps)
Roughing pumps
• Pumps from atm pressure down to rough
vacuum (0.1 Pa, 1X10-3 torr)
• Necessary because turbo pumps have trouble
starting from atmospheric pressure
• Usually Rotary Vane pumps
• Can have oil or not
Rotary vane pumps
Oil Sealed Rotary Pumps Understanding Gas Ballast www2.avs.org/chapters/nccavs/pdf/Gas_Ballast_OilSealedPumps.pdf
Rotary vane pumps
Condensation of vapor in the gas mixture is a problem with these
pumps. Solution Ballasting
Works by increasing the gas/vapor ratio (air is mostly gas)
As you might imagine this interferes with the final vacuum
Types
• One stage or two stage
• Belt Drive or direct drive
Slower 400-600
RPM
Bigger, Cheaper
Faster 1500 to
1725 RPM
Smaller, lighter
Turbo (molecular) pumps
• Gas molecules interact with
spinning blades and are
preferentially forced downward
• High vacuum (10-6 Pa) requires
rotation of 20,000 to 90,000
revolutions per minute
• Generally work between 10-3
and 10-7 Torr
• Ineffective before gas is in
“molecular flow”
Turbo (molecular) pumps
• Options:
– Bearings: Ceramic (oil lubricated) Magnetic
(supported w/out physical contact), also hybrid
– Rotor options (Blade configuration)
– Cooling (air or water)
Pump Care
Rough pumps shouldn’t need a lot of maintenance
If they do repair kits are available:
Minor kit includes all necessary seals (shaft seals, valves, o-rings, etc)
Major kit includes Minor Kit components plus vanes, springs, plugs, etc.
Seem to be available for most major brands and types
Turbopumps should need even less maintenance, bearings can wear out but
must be replaced by manufacturer for balancing.
http://www.sisweb.com/vacuum/sis/iseries-maintkit.htm
Pump specs
Displacement
Spec sheet for an
Edwards A65209903
RV rotary vane pump
$3171
50Hz
60Hz
Speed (Pneurop 6602)
3.7 m3h-1 / 2.2 ft3min-1
4.5 m3h-1 / 2.6 ft3min-1
50Hz
60Hz
Ultimate pressure (high vac mode)
3.3 m3h-1 / 2 ft3min-1
3.9 m3h-1 / 2.3 ft3min-1
2.0 x 10-3 mbar / 1.5 x 10-3 Torr
Ultimate pressure GB I (high vac mode)
3.0 x 10-2 mbar / 2.3 x 10-2 Torr
Ultimate pressure GB II (High throughput mode)
1.2 x 10-1 mbar / 9.1 x 10-2 Torr
Max inlet pressure for water vapour
80 mbar / 60 Torr
Max water vapour pumping rate – GB I
60 g/h
Max water vapour pumping rate – GB II
220 g/h
Max allowed outlet pressure
1 bar gauge / 14 psig
Max allowed inlet and gas ballast pressure
0.5 bar gauge / 7 psig
Motor power 50/60Hz
Nominal rotation speed 50/60Hz
450 / 550W
1500 / 1800rpm
Weight (without oil)
Oil capacity min/max
Recommended oil
Inlet flange
Exhaust flange
Noise level
Operating temperature range
25 kg / 55 lb
0.42/0.7 litres
Ultragrade 19
NW25
NW25
48 dBA @ 50 Hz
12 – 40 °C
Subset of specs for Edwards EXT 556H turbomolecular pump
Pumping Speed
Compression ratio
Ultimate Pressure (mbar)
Max continuous inlet pressure (light gas
pumping)†
Pump rotational speed
N2 ISO63/63CF (DN40NW)(ISO100)
He ISO63/63CF (DN40NW)(ISO100)
H2 ISO63/63CF (DN40NW)(ISO100)
N2
He
H2
With RV backing pump ISO/CF
With diaphragm backing pump ISO/CF
Outlet flange
Recommended backing pump*
Vent port
Purge port
Water cooling (water at 15 °C, ambient
temp at 40 °C)
Forced air cooled, 35 °C ambient
Nominal rotational speed
Standby rotational speed
Programmable power limit settings
Start time to 90% speed
Analogue outputs
Cooling method?
Ambient air temperature for forced air
cooling
Min cooling water flow rate (water 15
°C)
Water temp range
Max inlet flange temp
61 ls-1 (42 ls-1) (66 ls-1)
57 ls-1 (49 ls-1) (59 ls-1)
53 ls-1 (48 ls-1) (54 ls-1)
>1 × 1011
1 x 106
5 x 104
<5 x 10-9 / 5 x 10-10
<5 x 10-8 / 5 x 10-9
DN16NW
RV5/XDS5
1/8 inch BSP
1/8 inch BSP
2 × 10-2 mbar
1 × 10-2 mbar
90000 rpm
Variable from 49500 to 90000 rpm
(63000 rpm default)
Variable from 50-120W (80W default)
110 s ‡
Rotational speed;
Power consumption; Pump temp; Controller temp
Forced air / water
5 - 35 °C
15 l h-1
10 - 20 °C
100 °C
Turbo pumps: opposite
Pump Speed
Rotary Vane:
Pump speed lower at low vacuum
Pressure
Useful fitting terminology
• Flanges
– Standard quick Release (QF, KF,
NW, or DN)
• Named based on internal diameter
DN16KF is 16mm (16-50mm)
– Large Quick releases (LF, LFB, MF
or ISO)
• Clamps or bolts (63-500mm)
– Conflat (CF) used in ultra high
vacuum settings, usually metal
to metal seals
• Sizing odd: Europe inner diamter in
mm, NA outer diameter in inches
Sizes we will likely find.
www.vacuumresearchcorp.com/pdfs/valves/nwflanges06.pdf
Pumps on the Delta S
• Pumping system for Analyzer
– Turbo molecular pump TPH 050
– Vacuum pump E2 M1, 52
• Differential Pumping system
– Turbo molecular pump TPH 050
– Turbo molecular pump TPH 240
– Vorvakuumpumpe E2 M5, 50160 Hz
Turbo molecular pump TPH 050
Turbo molecular pump TPH 240
Units of pressure for your notes
Pascal
(Pa)
Bar
(bar)
1 Pa
≡ 1 N/m2
10−5
1 bar
105
1 at
Technical atmosphere
(at)
Pound-force
per
square inch
(psi)
Atmosphere
(atm)
Torr
(Torr)
1.0197×10−5
9.8692×10−6
7.5006×10−3
145.04×10−6
≡ 106 dyn/cm2
1.0197
0.98692
750.06
14.5037744
0.980665 ×105
0.980665
≡ 1 kgf/cm2
0.96784
735.56
14.223
1 atm
1.01325 ×105
1.01325
1.0332
≡ 1 atm
760
14.696
1 Torr
133.322
1.3332×10−3
1.3595×10−3
1.3158×10−3
≡ 1 Torr;
≈ 1 mmHg
19.337×10−3
1 psi
6.895×103
68.948×10−3
70.307×10−3
68.046×10−3
51.715
≡ 1 lbf/in2

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