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September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

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Page 1: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Helium Leak Testing Techniques for Industry.

Leak detection techniques

Page 2: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

If a system is leaking.......

....... you are in trouble!

Leak detection techniques

Page 3: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Finding a leak......

.......can also cause problems!

Leak detection techniques

Page 4: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Environmental

Safety ISO 9000

Product life

Reliability

Product specifications

Marketing advantage

Reasons for Leak Testing:

Leak detection techniques

Page 5: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Leak detection techniques

Application list

Analytical Mass spectrometer systemsElectron beam microscopes

AutomotiveACBrake tubingHeat exchnangerFuel tanksCompressorsEvaporatorsValves Thermostat

Medicine technologyPacemakerElectron microscopeX-ray tubesAmpulla

Power engineeringPower turbine Power condensorHigh voltage components

R&DHe bath cooler3He coolerIon beam acceleratorsUHV ^/XHV systemsHe transfer lines

ITTransfer chambersLoad looksTubing

Vaccum equipmentWhole vacuum programPump housings

Process industryFurnacesSoldering ovensHigh pressure vales

Page 6: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Automotive

BMW

Mercedes/DC

Audi

VW

Ford

Volvo

Peugeot

etc.

Cars Application Sub-systems

Pressure / Vac

Air conditionHe and refrig.

Pre-

tes t

with

He-

LD in

tegr

ated

in a

re

frig

eran

t fill

ing

unit

for A

C

Fuel tanks Walbro etc

tubes, hoses Contitech / Eaton

Valves Buerkert

Heat exchangers Behr

air bags Temic / Dyn.Nobel

high pressure Witzenmanbellows

injection pumps Bosch

Supplier

Leak detection techniques

Page 7: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Types of Leaks

Leaks at connectionsflanges, welding, soldering, grindings ( glass fittings)

Permeation leaksgas transport through materials e.g. elastomeric seals, glass

Porosity leaks castings

Virtual leaksgaps, small volumes in castings, evaporation of liquids, sintered metal, plastic parts

Hot /cold leakscracks open or close due to thermal tensions

Leak detection techniques

Page 8: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Volume of 1 liter

time /s

rise

pres

sure

mba

r

Definition of mbarl/s

Leak detection techniques

Page 9: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Water tap 1 drip per second 1,7x10-1 mbarl/s

Hair between O-ring and flange 1x10-3 - 5x10-2 mbarl/s

Bicycle tube in water 1x10-2 mbarl/s ( bubble test, 1 bubble/sec )

Car wheel loses air 4x10-5 mbarl/s 1,8 1,6 bar in 6 month

Leak detection techniques

Examples of well known leaks

Page 10: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Leak detection techniques

understanding particel size remarks for Helium

mbarl/s for air at 20°C

kg/h

water tight 10-2 10-5 drip

vapour tight 10-3 10-6 sweat

bacteria tight 10-4 10-7 d~10-6 m

fuel and oil tight 10-5 10-8

virus tight 10-6 10-9 d~0,3x10-6 m

gas tight 10-7 10-10

"absolut tight" 10-10 10-11 technical

leak rate range

Understanding of tightness

Page 11: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Procedure medium limit of leak ratembarl/s pressure range quantifiable

rise pressure air & others 10-4 vacuum limited

pressure drop air & others 10-4 overpressure limited

foaming agent air & others 10-5 overpressure no

bubble test air & others 10-4 overpressure limited

supersonic air & others 10-2 overpressure / low pressure no

thermal conductivity air & others 10-5 overpressure / low pressure no

mass spectrometerquadrupole refrigerents;gases 10-7 overpressure yes

mass spectrometermagnet. Sector field

HeliumHydrogen < 10-7 overpressure yes

mass spectrometermagnet. Sector field

HeliumHydrogen < 5x10-12 vacuum yes

Methods of Leak Tests

Leak detection techniques

Page 12: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

a) Leak

b) Desorbtion

c) Leak + Desorbtion

Pressure rise effects in a chamber

Leak detection techniques

Page 13: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Why is Helium a good Test Gas?

Low concentration in air , only 5 ppm, so low natural background

Inert gas, non toxic, non- explosive, environmentally friendly

Good separation in a mass spectrometer ( no cross sensitivity to other gases and no mass fragments

Lighter than air

Very small gas molecule, can easily pass through small holes/gaps

Leak detection techniques

Page 14: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Vacuum methodglobal detection ( He outside )

global detection ( He inside )

Local detection

Overpressure method

Local detection ( sniffing )

Principle Methods of Leak Detection

Leak detection techniques

Page 15: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Helium

3

Test unit( under vacuum)

1 Pressure chamber w Helium

2 Test vessel

3 Leak detector

4 Helium

5 Auxiliary Pump System

1

2

Lowest detectable leak rate < 5x10-12 mbarl/sGlobal Detection

Vacuum Method

Leak detection techniques

Page 16: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Vacuum Method

1 Vacuum chamber

2 Test body

3 Leak detector

4 Helium

5 Auxiliary Pump System for huge vessels

Global Detection

3

Lowest detectable leak rate < 5x10-12 mbarl/s

Leak detection techniques

Page 17: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Vacuum Method

Local Detection

1 Spray gun

2 Test body

3 Leak detector

4 Helium

5 Auxiliary Pump System

(for large vessels)

3

Lowest detectable leak rate < 5x10-12 mbarl/s

Leak detection techniques

Page 18: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

y

Overpressure Method

Local Detection (sniffing) Lowest detectable leak rate < 1x10-7 mbarl/s!!!

1 Sniffer probe

2 Test vessel

3 Leak detector

4 Helium

3

Leak detection techniques

Page 19: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Worked sample

How long does it takes to rise the pressure in a volume of 1 l from 1 to 2 mbar if a leak of 1x10-6 mbarl/s is present?

1x10-6mbarl/s

q L = V /t ∗ Δp

V = 1 l

Δp = 1mbar

q L = 1x10-6mbarl/s

t = V / qL ∗ Δp

= 1l / 1x10-6mbarl/s ∗

1 mbar

= 100 000s

= 277,7h

= 11,5d

Leak detection techniques

Page 20: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Pressure rise method with vacuum ( no Helium )

Example:

Test volume: V = 1m³

Δp: p = 1 · 10-3 mbar until 8 · 10-3 mbar

Time : t = 5 min

QL = ??

Q =

=

=

V t

· Δ

p [mbar · l · s-1]

1000 l 300 s · 7 · 10-3 mbar

2,33 · 10-2 mbar · l · s-1

Δ

p = p2 – p1 = 8 · 10-3 – 1 · 10-3 = 7 · 10-3 mbar

Air leak rate

Leak detection techniques

Page 21: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Partial Flow System

Leak detection techniques

Page 22: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Partial Flow Principle

Chamber

PhoeniXL300

SLD = 2,5 l / s

SP = 60 m³ / h = 16,66 l / s

QHe = 3 · 10-5 mbar · l / s

Auxiliary pump

Test leak

The Helium flow will be splitted into 2 directions

2,5 2,5 + 16,66Flow to LD QL : 3 · 10-5 · = 3,9 · 10-6 mbar · l / s

16,66 2,5 + 16,66Flow to auxiliary pump QP : 3 · 10-5 · = 2,6 · 10-5 mbar · l / s

Total = 3 · 10-5 mbar · l / s

display LD leak rate Test leakFlow ratio γ

=

p QHe =Ssum . p

QL =SLD . p

QL =QHe . SLD /Sp +SLD

p = QHe /Ssum

Ssum = SLD + SP

Leak detection techniques

Page 23: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Partial Flow SystemLeak detection techniques

Page 24: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

1↓ = ... → mbar · l/s kg·h–1 kg·h–1 cm3/h cm3/s Torr · l/s g/a g/a m · cfm lusec Pa · l/s slpm (20 °C) (0 °C) (NTP) (NTP) (F12. 20 °C) (F12. 25°C)

mbar · l/s 1 4.28 · 10–3 4.59 · 10–3 3554 0.987 0.75 1.56 · 105 1.54 · 105 1593 7.52 · 102 100 59.2 · 10–3

kg · h–1 (20 °C) 234 1 1.073 8.31 · 105 231 175 – – 37.2 · 104 1.75 · 105 23.4 · 103 13.86

kg · h–1 (0 °C) 218 0.932 1 7.74 · 105 215 163 – – 34.6 · 104 1.63 · 105 21.8 · 103 12.91

cm3/h (NTP) 2.81 · 10–4 1.20 · 10–6 1.29 · 10–6 1 2.78 · 10–4 2.11 · 10–4 44 – 44.7 · 10–2 2.11 · 10–1 2.81 · 10–2 1.66 · 10–5

cm3/s (NTP) 1.013 4.33 · 10–3 4.65 · 10–3 3600 1 0.760 1.58 · 105 – 1611 760 101 6 · 10–2

Torr · l/s 1.33 5.70 · 10–3 6.12 · 10–3 4727 1.32 1 2.08 · 105 2.05 · 105 2119 1 · 103 133 78.8 · 10–3

g/a (F12. 20 °C) 6.39 · 10–6 – – 2.27 · 10–2 6.31 · 10–6 4.80 · 10–6 1 – 10.2 · 10–3 4.8 · 10–3 6.39 · 10–4 37.9 · 10–8

g/a (F12. 25 °C) 6.50 · 10–6 – – – – 4.88 · 10–6 – 1 10.4 · 10–3 4.89 · 10–3 6.5 · 10–4 38.5 · 10–8

m · cfm 6.28 · 10–4 2.69 · 10–6 2.89 · 10–6 2.24 6.21 · 10–4 4.72 · 10–4 98.16 96.58 1 0.472 6.28 · 10–2 37.2 · 10–6

lusec 1.33 · 10–3 5.70 · 10–6 6.12 · 10–6 4.737 1.32 · 10–3 1 · 10–3 208 205 2.12 1 13.3 · 10–2 78.8 · 10–6

Pa · l/s 1 · 10–2 4.28 · 10–5 4.59 · 10–5 35.54 9.87 · 10–3 7.5 · 10–3 1.56 · 103 1.54 · 103 15.93 7.50 1 59.2 · 10–5

slpm 16.88 72.15 · 10–3 77.45 · 10–3 60.08 · 103 16.67 12.69 2.64 · 106 2.60 · 106 26.9 · 103 12.7 · 103 16.9 · 102 1

Conversion of mass flowes-(Leak Rates)

1 cm3 (NTP) = 1 cm3 under normal condition (T = 273.15 K; p = 1013.25 mbar)NTP = normal temperature and pressure (1 atm; 0 °C) R = 83.14 mbar · l · mol–1 · K–11 cm3 (NTP) · h–1 = 1 atm · cm3 · h–1 = 1 Ncm3 · h–1 = 1 std cch1 sccm = 10–3 slpm = 10–3 N · l · min–1 = 60 sccsSI-System kohärent: 1 Pa · m3 · s–1 = 10 mbar · l · s–1; R = 8.314 Pa · m3 · mol–1 · K–1; M in kg / mol1 cm3 (NTP) · s–1 = 1 sccs = 60 cm3 (NTP) · min–1 60 sccm = 60 std ccm = 60 Ncm3 · min–1

1 lusec = 1 l · μ · s–1 1 · μ = 1 micron = 10–3 Torr 1 lusec = 10–3 Torr · l · s–1

Freon F 12 (CCl2F2) M = 120.92 g · mol–1; Luft M = 28.96 g · mol–1

Achtung: Anglo-amerikanische Einheiten werden uneinheitlich abgekürzt! Beispiel: Standard cubic centimeter per minute → sccm = sccpm = std ccm = std ccpm

Leak detection techniques

Page 25: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Technical DataPhoeniXL300 PhoeniXL300 Dry PhoeniXL300Modul

Lowest detectable He leak rate ( vacuum mode ) mbarl/s <5x10-12 <3x10-11 <5x10-12 / <8x10 -12

Lowest detectable leak rate ( sniffer mode ) mbarl/s <1x10-7 <1x10-7 <1x10-8

Max. detectable He leak rate ( vacuum mode ) mbarl/s > 0,1 > 0,1 > 0,1

Max. permissable inlet pressure mbar 15 15 15

Max. permeissable inlet pressure w partial flow set mbar 1000 - -

Pumping speed during pump down m3 2,5 ( 50 Hz )3 ( 60 Hz )

1,6 ( 50 Hz )1,8 ( 60 Hz )

16/20 ( 50 / 60 Hz ) D16B25/30 ( 50 / 60 Hz )D25B30/36 ( 50 / 60 Hz )Scroll

Pumping speed for Helium l/s > 2,5 > 2,5 > 2,5

Pumping speed with partial flow set and D16B l/s 16 ( 50Hz)

Pumping speed with partial flow set and D25B l/s 25 ( 50 Hz )

Time constant for leak rate signal s < 1 <1 <1

Time until ready for operation min < 2 < 2 < 2

Mass spectrometer

Detectable masses 4He; 3 He ; H2 amu 4; 3 ; 2 4; 3 ; 2 4; 3 ; 2

Relay outputs 4 4 4

SPS inputs 6 6 6

Test port connection

Length of hand unit cable ( option ) m 4 ( max. 32 ) 4 ( max. 32 ) 4 ( max. 32 )

Power consumption 420 VA 350 VA 350 VA

Dimensions ( L x H x D ) mm 495 x 456 x 314 495 x 456 x 314 495 x 456 x 314

Weight kg 40 37,5 29

180° magn. Sector field

DN 25 KF

PhoeniXL300Modul pump connection flange size DN25KF

Leak detection techniques

Page 26: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

PhoeniXL340

LD work station for serial production of small parts

Customised test stations(Customized by OLV)

Leak detection techniques

Page 27: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009

Page 28: Leak detection techniques Helium Leak Testing Techniques ... · September 2009 Helium Leak Testing Techniques for Industry. Leak detection techniques

September 2009