US5317900A — Ultrasensitive helium leak detector for large sys…

Claim 1

Independent Claim 161 words

A leak detector for sensing a test gas leaking into a vacuum chamber comprising a vacuum chamber having an opening, a momentum transfer pump having means to compress the gases coming from the vacuum chamber, connected to said opening of said vacuum chamber, an entrainment pump connected to receive the gases exhausted from said momentum transfer pump, said entrainment pump having means for entrapping the active exhaust gases coming from the vacuum chamber, but not the noble gases, which remain in a gaseous state, a mass spectrometer connected to receive the output from said entrainment pump, the entrapment of the active exhaust gas by said entrainment pump reducing the total pressure at said mass and measurement by said mass detector of extremely small amounts of the noble gas, and a second momentum transfer pump for evacuating gases after the noble gases have accumulated, and a positive displacement pump for exhausting the gases to the atmosphere from said second momentum transfer pump.

Claim 2

Dependent Claim 161 words

A leak detector for sensing a test gas leaking into a vacuum chamber comprising a vacuum chamber having an opening, a momentum transfer pump having means to compress the gases coming from the vacuum chamber, connected to said opening of said vacuum chamber, an entrainment pump connected to receive the gases exhausted from said momentum transfer pump, said entrainment pump having means for entrapping the active exhaust gases coming from the vacuum chamber, but not the noble gases, which remain in a gaseous state, a mass spectrometer connected to receive the output from said entrainment pump, the entrapment of the active exhaust gas by said entrainment pump reducing the total pressure at said mass and measurement by said mass detector of extremely small amounts of the noble gas, and a second momentum transfer pump for evacuating gases after the noble gases have accumulated, and a positive displacement pump for exhausting the gases to the atmosphere from said second momentum transfer pump.

Claim 3

Dependent Claim 15 words

The leak detector as recited in claim 1 in which the noble gas is helium.

Claim 4

Dependent Claim 15 words

The leak detector as recited in claim 1 in which the noble gas is argon.

Claim 5

Dependent Claim 38 words

The leak detector as recited in claim 1 wherein said momentum transfer pump used to compress the gas from the vacuum chamber is a magnetic turbomolecular pump, and said second momentum transfer pump is a standard turbomolecular pump.

Claim 6

Dependent Claim 17 words

The leak detector as recited in claim 1 wherein said momentum transfer pumps are standard turbomolecular pump.

Claim 7

Dependent Claim 18 words

The leak detector as recited in claim 1 wherein said momentum transfer pumps are a molecular drag pump.

Claim 8

Dependent Claim 17 words

The leak detector as recited in claim 1 wherein said momentum transfer pumps are a diffusion pump.

Claim 9

Dependent Claim 17 words

The leak detector as recited in claim 1 wherein said entrainment pump is a pelletized getter pump.

Claim 10

Dependent Claim 19 words

The leak detector as recited in claim 1 wherein said entrainment pump is of the cartridge type of getter.

Claim 11

Dependent Claim 17 words

The leak detector as recited in claim 1 wherein said entrainment pump is of the cryopump type.

Claim 12

Dependent Claim 17 words

The leak detector as recited in claim 1 wherein said entrainment pump is of the sorption type.

Claim 13

Dependent Claim 15 words

The leak detector as recited in claim 1 wherein said mass spectrometer is a quadrupole.

Claim 14

Dependent Claim 18 words

The leak detector as recited in claim 1 wherein said mass spectrometer is of the magnetic sector type.

Claim 15

Dependent Claim 22 words

A leak detector as recited in claim 1 for sensing a test gas leaking from a device contained in said vacuum chamber.

Claim 16

Dependent Claim 162 words

A process for sensing a noble gas leaking into a vacuum chamber comprising the steps of: providing a vacuum chamber having an opening, connecting a momentum transfer pump to said opening of said vacuum chamber, connecting an entrainment pump to receive the exhaust gases from said momentum transfer pump, said entrainment pump entrapping the active exhaust gases coming from the vacuum chamber, but not a noble gas, which remains in a gaseous state, and connecting a mass spectrometer to receive the output from said entrainment pump, the entrapment of the active exhaust gases by said entrainment pump reducing the pressure at said mass spectrometer detector, thus making possible the detection and measurement by said mass spectrometer gas detector of extremely small amounts of the noble gas, and connecting a momentum transfer pump and positive displacement pump by means of a duct in which a valve is located, whereby the noble gases and residual gases can be evacuated before continuing with subsequent tests.

Claim 17

Dependent Claim 162 words

A process for sensing a noble gas leaking into a vacuum chamber comprising the steps of: providing a vacuum chamber having an opening, connecting a momentum transfer pump to said opening of said vacuum chamber, connecting an entrainment pump to receive the exhaust gases from said momentum transfer pump, said entrainment pump entrapping the active exhaust gases coming from the vacuum chamber, but not a noble gas, which remains in a gaseous state, and connecting a mass spectrometer to receive the output from said entrainment pump, the entrapment of the active exhaust gases by said entrainment pump reducing the pressure at said mass spectrometer detector, thus making possible the detection and measurement by said mass spectrometer gas detector of extremely small amounts of the noble gas, and connecting a momentum transfer pump and positive displacement pump by means of a duct in which a valve is located, whereby the noble gases and residual gases can be evacuated before continuing with subsequent tests.

Claim 18

Dependent Claim 80 words

The process for sensing a noble gas leaking into a vacuum chamber as recited in claim 15 wherein the entrainment pump connected on the exhaust side of the momentum transfer pump removes active gases, collecting and containing noble gases, and measuring the level of these noble gases continuously during leak checking, said process further involving the rapid evacuation of the exhaust gases when the leak test is complete, such that another test can be started without first pressurizing the chamber.

Claim 19

Dependent Claim 65 words

The process for sensing a noble gas leaking into a vacuum chamber as recited in claim 15 wherein said momentum transfer pump serves to increase the concentration of noble gases that leak into a high vacuum chamber by the steps of collecting, compressing and containing those noble gases in a reduced volume consisting of conduits, valves, entrainment pump and a housing containing said mass spectrometer.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1997-06-06	1997-12-06	1998-06-07	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2001-06-06	2001-12-06	2002-06-07	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2005-06-06	2005-12-06	2006-06-07	$7700.00	Window Closed / Lapsed

Ultrasensitive helium leak detector for large systems

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