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BASIC VACUUM PRACTICE. To move a particle in a (straight) line over a large distance. Why is a Vacuum Needed?. (Page 5 manual). To provide a clean surface. Why is a Vacuum Needed?. (High)Vacuum. Atmosphere. Contamination (usually water). Clean surface. HOW DO WE CREATE A VACUUM?.

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why is a vacuum needed1
To provide a clean surfaceWhy is a Vacuum Needed?

(High)Vacuum

Atmosphere

Contamination

(usually water)

Clean surface

slide5
VACUUM PUMPS

(METHODS)

Gas Transfer

Vacuum Pump

Entrapment

Vacuum Pump

Kinetic

Vacuum Pump

Adsorption

Pump

Positive Displacement

Vacuum Pump

Drag

Pump

Rotary

Pump

Fluid Entrainment

Pump

Ion Transfer

Pump

Reciprocating

Displacement Pump

Cold Trap

Ejector

Pump

Bulk Getter

Pump

Getter

Pump

Gaseous

Ring Pump

Diaphragm

Pump

Liquid Ring

Pump

Turbine

Pump

Liquid Jet

Pump

Diffusion

Pump

Getter Ion

Pump

Sublimation

Pump

Piston

Pump

Rotary

Piston Pump

Gas Jet

Pump

Diffusion

Ejector Pump

Self Purifying

Diffusion Pump

Axial Flow

Pump

Evaporation

Ion Pump

Multiple Vane

Rotary Pump

Sliding Vane

Rotary Pump

Vapor Jet

Pump

Fractionating

Diffusion Pump

Radial Flow

Pump

Sputter Ion

Pump

Rotary

Plunger Pump

Molecular

Drag Pump

Dry

Pump

Roots

Pump

Cryopump

Turbomolecular

Pump

Condenser

VACUUM PUMPING METHODS

barometer
BAROMETER

Mercury: 13.58 times heavier than water: Column is 13.58 x shorter :

10321 mm/13.58=760 mm (= 760 Torr)

10.321

mm

29,9

in

760

mm

WATER

MERCURY

(Page 12 manual)

slide7
PRESSURE OF 1 STANDARD

ATMOSPHERE:

760 TORR, 1013 mbar

AT SEA LEVEL, 0O C AND 45O LATITUDE

pressure equivalents
Atmospheric Pressure (Standard) =

gauge pressure (psig)

pounds per square inch (psia)

inches of mercury

millimeter of mercury

torr

millitorr or microns

pascal

bar

millibar

0

14.7

29.9

760

760

760,000

101,325

1.013

1013

Pressure Equivalents
slide9
PARTIAL PRESSURES OF GASES CORRESPOND TO THEIR RELATIVE VOLUMES

PARTIAL PRESSURE

PERCENT BY

VOLUME

GAS

SYMBOL

PASCAL

TORR

N2

O2

A

CO2

Ne

He

Kr

H2

X

H2O

78

21

0.93

0.03

0.0018

0.0005

0.0001

0.00005

0.0000087

Variable

593

158

7.1

0.25

1.4 x 10-2

4.0 x 10-3

8.7 x 10-4

4.0 x 10-4

6.6 x 10-5

5 to 50

79,000

21,000

940

33

1.8

5.3 x 10-1

1.1 x 10-1

5.1 x 10-2

8.7 x 10-3

665 to 6650

Nitrogen

Oxygen

Argon

Carbon Dioxide

Neon

Helium

Krypton

Hydrogen

Xenon

Water

THE ATMOSPHERE IS A MIXTURE OF GASES

(Page 13 manual)

slide10
P (mbar)

1013

32

6.4

0.13

6.6 x 10 -4

10 -24

T (O C)

100

25

0

-40

-78.5

-196

(BOILING)

(FREEZING)

(DRY ICE)

(LIQUID NITROGEN)

VAPOR PRESSURE OF WATER AT VARIOUS TEMPERATURES

(Page 14 manual)

pressure ranges
PRESSURE RANGES

RANGE

ROUGH (LOW) VACUUM

HIGH VACUUM

ULTRA HIGH VACUUM

PRESSURE

759 TO 1 x 10 -3 (mbar)

1 x 10 -3 TO 1 x 10 -8 (mbar)

LESS THAN 1 x 10 -8 (mbar)

(Page 17 manual)

gas flow conductance
GAS FLOWCONDUCTANCE

(Page 24 manual)

viscous and molecular flow
Viscous Flow

(momentum transfer

between molecules)

Molecular Flow

(molecules move

independently)

Viscous and Molecular Flow
flow regimes
FLOW REGIMES

Viscous Flow:

Distance between molecules is small; collisions between

molecules dominate; flow through momentum transfer;

generally P greater than 0.1 mbar

Transition Flow:

Region between viscous and molecular flow

Molecular Flow:

Distance between molecules is large; collisions between

molecules and wall dominate; flow through random motion;

generally P smaller than 10 mbar

-3

(Page 25 manual)

mean free path
1013 mbar (atm)

1 x 10-3 mbar

1 x 10-9 mbar

#

mol/cm3

3 x 10 19

4 x 10 13

4 x 10 7

(30 million trillion)

(40 trillion)

(40 million)

2 inches

5.1 cm

2.5 x 10-6 in

6.4 x 10-5 mm

31 miles

50 km

MFP

MEAN FREE PATH

MOLECULAR DENSITY AND MEAN FREE PATH

flow regimes1
Mean Free Path

Characteristic Dimension

is less than 0.01

Viscous Flow:

Mean Free Path

Characteristic Dimension

is between 0.01 and 1

Transition Flow:

Mean Free Path

Characteristic Dimension

is greater than 1

Molecular Flow:

FLOW REGIMES
conductance in viscous flow
Conductance in Viscous Flow

Under viscous flow conditions doubling the

pipe diameter increases the conductance

sixteen times.

The conductance is INVERSELY related to

the pipe length

(Page 28 manual)

conductance in molecular flow
Conductance in Molecular Flow

Under molecular flow conditions doubling

the pipe diameter increases the conductance

eight times.

The conductance is INVERSELY related to

the pipe length.

slide21
Series Conductance

RT = R1 + R2

SYSTEM

1 = 1 + 1

C2

CT

C1

C1

1 = C1 + C2

CT

C2

C1 x C2

CT = C1 x C2

C1 + C2

PUMP

(Page 29 manual)

gas load
GAS LOAD

Permeation

Outgassing

Real

Leaks

Virtual

Diffusion

Backstreaming

GAS LOAD (Q) IS EXPRESSED IN:

mbar liters per second

pumpdown curve
Pumpdown Curve

10+1

10-1

Volume

10-3

10-5

Surface Desorption

Pressure (mbar)

10-7

Diffusion

10-9

Permeation

10-11

10 1

10 7

10 11

10 3

10 5

10 13

10 15

10 17

10 9

Time (sec)

roughing pumps
Roughing Pumps

2

(Page 39 manual)

slide25
VACUUM PUMPS

(METHODS)

Gas Transfer

Vacuum Pump

Drag

Pump

Fluid Entrainment

Pump

Ejector

Pump

Bulk Getter

Pump

Gaseous

Ring Pump

Getter Ion

Pump

Sublimation

Pump

Evaporation

Ion Pump

Fractionating

Diffusion Pump

Molecular

Drag Pump

Turbomolecular

Pump

Condenser

VACUUM PUMPING METHODS

Entrapment

Vacuum Pump

Kinetic

Vacuum Pump

Adsorption

Pump

Positive Displacement

Vacuum Pump

Rotary

Pump

Ion Transfer

Pump

Reciprocating

Displacement Pump

Cold Trap

Getter

Pump

Diaphragm

Pump

Liquid Ring

Pump

Turbine

Pump

Liquid Jet

Pump

Diffusion

Pump

Piston

Pump

Rotary

Piston Pump

Gas Jet

Pump

Diffusion

Ejector Pump

Self Purifying

Diffusion Pump

Axial Flow

Pump

Multiple Vane

Rotary Pump

Sliding Vane

Rotary Pump

Vapor Jet

Pump

Radial Flow

Pump

Sputter Ion

Pump

Rotary

Plunger Pump

Dry

Pump

Roots

Pump

Cryopump

pump operating ranges
Rotary Vane Mechanical Pump

Rotary Piston Mechanical Pump

Dry Mechanical Pump

Sorption Pump

Blower/Booster Pump

Venturi Pump

PUMP OPERATING RANGES

Ultra High

Vacuum

Rough Vacuum

High Vacuum

High Vac. Pumps

Ultra-High Vac. Pumps

10-12

10-6

10-2

10-10

10-8

1

10+2

10-4

P (mbar)

vacuum system use
Chamber

High Vac. Pump

Roughing Pump

Foreline Pump

Hi-Vac. Valve

Roughing Valve

Foreline Valve

Vent Valve

Roughing Gauge

High Vac. Gauge

1

2

3

3a

4

5

6

7

8

9

VACUUM SYSTEM USE

9

8

1

7

8

5

4

7

2

6

3

3a

(Page 44 manual)

how the pump works
How the Pump Works

(Page 46 manual)

oil backstreaming
2OIL BACKSTREAMING

PRESSURE LEVELS: LESS THAN 0.2 mbar

blower booster pump
Blower/Booster Pump

(Page 61 manual)

vacuum system use1
Chamber

Foreline

Roughing Valve

Roughing Gauge

Roughing Pump

Foreline

Foreline Valve

Foreline Gauge

High Vacuum Valve

Booster/Blower

Vent Valve

High Vacuum Gauge

1

2

3

4

5

6

7

8

9

10

11

12

12

11

1

4

3

2

9

10

7

6

8

5

VACUUM SYSTEM USE

(Page 62 manual)

sorption pump components
Sorption Pump Components

(Page 54 manual)

vapor pressure
Vapor Pressure

(Page 56 manual)

cryo sorption
Cryo-sorption

(Page 55 manual)

high vacuum pumps
HIGH VACUUM PUMPS

3

(Page 63 manual)

slide42
VACUUM PUMPS

(METHODS)

Gas Transfer

Vacuum Pump

Drag

Pump

Fluid Entrainment

Pump

Ejector

Pump

Bulk Getter

Pump

Getter Ion

Pump

Sublimation

Pump

Evaporation

Ion Pump

Fractionating

Diffusion Pump

Molecular

Drag Pump

Turbomolecular

Pump

Condenser

VACUUM PUMPING METHODS

Entrapment

Vacuum Pump

Kinetic

Vacuum Pump

Adsorption

Pump

Positive Displacement

Vacuum Pump

Rotary

Pump

Ion Transfer

Pump

Reciprocating

Displacement Pump

Cold Trap

Getter

Pump

Gaseous

Ring Pump

Diaphragm

Pump

Liquid Ring

Pump

Turbine

Pump

Liquid Jet

Pump

Diffusion

Pump

Piston

Pump

Rotary

Piston Pump

Gas Jet

Pump

Diffusion

Ejector Pump

Self Purifying

Diffusion Pump

Axial Flow

Pump

Multiple Vane

Rotary Pump

Sliding Vane

Rotary Pump

Vapor Jet

Pump

Radial Flow

Pump

Sputter Ion

Pump

Rotary

Plunger Pump

Dry

Pump

Roots

Pump

Cryopump

pump operating ranges1
PUMP OPERATING RANGES

Ultra High

Vacuum

Rough Vacuum

High Vacuum

Roughing Pumps

Liquid Nitrogen Trap

Diffusion Pump

Turbo Pump

Cryo Pump

Ion Pump

Tit. Subl. Pump

10-12

10-6

10-2

10-10

10-8

1

10+2

10-4

P (Torr)

vacuum system use2
Chamber

High Vac. Pump

Roughing Pump

Fore Pump

Hi-Vac. Valve

Roughing Valve

Foreline Valve

Vent Valve

Roughing Gauge

High Vac. Gauge

1

2

3

3a

4

5

6

7

8

9

VACUUM SYSTEM USE

9

8

1

7

8

5

4

8

2

2

6

3

3a

pump construction
Pump Construction

(Page 66 manual)

pumping speed
1

2

3

4

Critical Point

Pumping Speed (Air)

1. Compression Ratio Limit

2. Constant Speed

3. Constant Q (Overload)

4. Mechanical Pump Effect

10-10

10--3

10--1

Inlet Pressure (Torr)

Pumping Speed
how the ln2 trap works
How the LN2 Trap Works

Approximate Vapor

Pressure (mbar)

Gas

Water (H2O)

Argon (A)

Carbon Dioxide (CO2)

Carbon Monoxide (CO)

Helium (He)

Hydrogen (H2)

Oxygen (O2)

Neon (Ne)

Nitrogen (N2)

Solvents

10-22

500

10 -7

>760

>760

>760

350

>760

760

<10 -10

(Page 79 manual)

turbomolecular pump
Turbomolecular Pump

INLET FLANGE

ROTOR BODY

STATOR BLADES

HIGH PUMPING SPEED

HIGH COMPRESSION

BEARING

EXHAUST

HIGH FREQ. MOTOR

BEARING

(Page 81 manual)

rotor stator assembly
Rotor - stator assembly

(Page 82 manual)

pump operation
Pump Operation

Molecule

V

Moving Wall with Speed V

Principle of the Turbomolecular Pump

(Page 83 manual)

roughing through the turbo
6

7

Chamber

Turbo Pump

Roughing Pump

Vent Valve

Roughing Gauge

High Vac. Gauge

1

2

3

4

5

6

1

4

5

2

2

3

Roughing through the turbo

(Page 91 manual)

cryosorption in charcoal
Cryosorption in charcoal

(Page 98 manual)

gauges
Gauges

5

(Page 123 manual)

gauge operating ranges
Bourdon Gauge

Capacitance Manometer

Thermocouple Gauge

Pirani Gauge

Hot Fil. Ion Gauge

Cold Cathode Gauge

McLeod Gauge

Gauge Operating Ranges

Ultra High

Vacuum

Rough Vacuum

High Vacuum

Residual Gas Analyzer

Spinning Rotor Gauge

10-12

10-6

10-2

10-10

10-8

1

10+2

10-4

P (mbar)

heat transfer gauges

Heat Transfer Gauges

Thermocouple gauge

and

Pirani Gauge

rga spectrum
NORMAL (UNBAKED)

SYSTEM

H2O

RELATIVE INTENSITY

(A)

N2,, CO

H2

CO2

MASS NUMBER (A.M.U.)

RGA SPECTRUM
rga spectrum1
N2

SYSTEM WITH

AIR LEAK

H2O

RELATIVE INTENSITY

(B)

O2

H2

CO2

MASS NUMBER (A.M.U.)

RGA SPECTRUM
leak detection

LEAK DETECTION

9

(Page 249 manual)

problems that appear to be leaks
Permeation

Diffusion

Real

Leaks

Virtual

Outgassing

Backstreaming

Problems that appear to be Leaks
double o ring sealed shafts
Double O ring sealed shafts

Atmosphere

(760 torr)

Vacuum

differential pumping
Differential Pumping

Atmosphere

(1013 mbar)

Vacuum

1 mbar

To Pump

permeation leaks

PERMEATION LEAKS

Permeation “leaks” are different than real leaks because the only way to stop them is to change to a less permeable material

leak rates over time
Leak Rates over Time

LEAK RATES

10 -1 STD CC/SEC --- 1 CC/10 SEC

10 -3 STD CC/SEC --- 3 CC/HOUR

10 -5 STD CC/SEC --- 1 CC/DAY

10 -6 STD CC/SEC --- 1 CC/2 WEEKS

10 -7 STD CC/SEC --- 3 CC/YEAR

10 -9 STD CC/SEC --- 1 CC/30 YEARS

helium
HELIUM
  • Helium is very light and small
  • Low concentration in air (0.0005%)
  • Permits dynamic testing
  • Permits non-destructive testing
  • Helium is safe
conventional leak detector
Test Piece

Test Port

High Vac. Pump

Roughing Pump

Fore Pump

RoughingValve

Test Valve

Pump Valve

Spectrometer Tube

Cold Trap

Roughing Gauge

Vent Valve

1

2

3

4

5

6

7

8

9

10

11

12

5

CONVENTIONAL LEAK DETECTOR

1

2

12

11

10

9

7

6

8

3

4

ion separation in magnetic field
Ion Separation in Magnetic Field

Ion Gauge

Ion Source

To Pre-Amplifier

Magnetic Field

Deflects He Ions

90O, other ions

more or less than

90O.

Lighter ions:

more

Collector

He ions pass

through slit and

are collected

Heavier ions:

less

ad