Leak detection system

Claim 2

In a leak-detection system for detecting leaks in vacuum vessels and containers, which system comprises helium-detection means for sensing the presence of helium, which helium is a probe gas injected into a vacuum vessel or container being tested for leaks, high-vacuum pump means connected to said helium-detection means for forming a high vacuum in said helium-detection means, means for directing helium probe gas from a leak to the outlet of said high-vacuum pump means, and support pump means connected to the outlet of said high-vacuum pump means for exhausting the system to the environmental surroundings, the improvement comprising: said high-vacuum pump means comprising a molecular drag pump having an inlet in fluid communication with the interior of said helium-detection means, and an outlet in fluid communication with said means for directing.

Claim 3

The improvement according to claim 1, wherein said means for directing introduces the helium probe gas from a leak to said outlet of said molecular drag pump in a flow having turbulent flow characteristics.

Claim 4

The improvement according to claim 2, wherein said flow also comprises laminar and transitional flow characteristics.

Claim 5

The improvement according to claim 2, wherein said means for directing comprises conduit means in fluid communication with said outlet of said molecular drag pump for fluidly coupling said outlet with the leaking helium.

Claim 6

The improvement according to claim 1, wherein said support pump means comprises at least one oil-free pump having an inlet fluidly coupled to said outlet of said molecular drag pump; said means for directing directing the leaking helium probe gas between said outlet of said molecular drag pump and said inlet of said at least one oil-free pump.

Claim 7

The improvement according to claim 5, wherein said support pump means comprises a plurality of oil-free dry pumps, at least one thereof being a dry diaphragm pump and at least one thereof being a dry piston pump.

Claim 8

The improvement according to claim 6, wherein said support pump means comprises a pair of series-connected diaphragm pumps, and a pair of series-connected piston pumps, said diaphragm pumps being positioned upstream and closer to said molecular drag pump as compared to said piston pumps, each said pump of said support pump means comprising an inlet and an outlet.

Claim 9

The improvement according to claim 7, further comprising means for introducing leaking helium probe gas between one said outlet of one said pump of said support pump means and one said inlet of another, directly adjacent pump of said support pump means for detecting gross leaks.

Claim 10

The improvement according to claim 5, wherein support pump means comprises a plurality of dry pumps connected in series, each of said plurality of pumps having an inlet and an outlet; and means for introducing leaking helium probe gas between one said outlet of one of said plurality of pumps and one said inlet of another, directly adjacent pump of said plurality of pumps, whereby gross leaks may be detected.

Claim 11

The improvement according to claim 1, further comprising means for injecting a stream of higher-pressure ambient gas into said outlet of said molecular drag pump for purging said helium-detection means and the remainder of the system of accumulated helium.

Claim 12

A leak-detection system for detecting leaks in vacuum vessels and containers, comprising: a mass spectrometer comprising a detecting chamber and means for sensing the presence of a probe gas in said detecting chamber, said detecting chamber being evacuated to a high vacuum; first pump means connected to said detecting chamber for forming a high vacuum therein; said first pump means comprising a molecular drag pump having an inlet port coupled connected to said detecting chamber, and an outlet exhaust port; second pump means having an inlet port connected to said exhaust port of said molecular drag pump, said second pump means also having an outlet port; a third pump means having an inlet port connected to said outlet port of said second pump means, and an outlet port, said second and third pump means supporting said molecular drag pump; means for introducing leaking probe gas into at least one of said exhaust port of said molecular drag pump and said exhaust port of said second pump means, whereby the probe gas by dynamic mixing flows backwardly into said detecting chamber of said mass spectrometer.

Claim 13

A leak-detection system for detecting leaks in vacuum vessels and containers, comprising: a mass spectrometer comprising a detecting chamber and means for sensing the presence of a probe gas in said detecting chamber, said detecting chamber being evacuated to a high vacuum; first pump means connected to said detecting chamber for forming a high vacuum therein; said first pump means comprising a molecular drag pump having an inlet port coupled connected to said detecting chamber, and an outlet exhaust port; second pump means having an inlet port connected to said exhaust port of said molecular drag pump, said second pump means also having an outlet port; a third pump means having an inlet port connected to said outlet port of said second pump means, and an outlet port, said second and third pump means supporting said molecular drag pump; means for introducing leaking probe gas into at least one of said exhaust port of said molecular drag pump and said exhaust port of said second pump means, whereby the probe gas by dynamic mixing flows backwardly into said detecting chamber of said mass spectrometer.

Claim 14

The leak-detection system according to claim 11, further comprising a fourth pump means having an inlet port connected to said exhaust port of said third pump means, and an outlet port; and a fifth pump means having an inlet port connected to said exhaust port of said fourth pump means and outlet port, said fourth and fifth pump means serving also as support pumps, for bringing the exhaust of the system up to atmospheric.

Claim 15

The leak-detection system according to claim 12, wherein said means for introducing leaking probe gas further comprises means for introducing the leaking probe gas at the exhaust port of at least one of said third and fourth pumps.

Claim 16

The leak-detection according to claim 13, wherein each of said second and third pump means comprises a diaphragm pump, and each of said fourth and fifth pump means comprises a piston pump.

Claim 17

The leak-detection system according to claim 11, further comprising air purging means for injecting ambient gas into the exhaust port of one of said pump means for purging the system of any accumulated probe gas.

Claim 18

The leak-detection system according to claim 15, wherein said probe gas is helium; and said means for introducing the probe gas comprises means for injecting helium to a respective said exhaust port such that the helium has turbulent, laminar, and transitional flow characteristics.

Claim 21

The method according to claim 17, wherein said step of directing comprises directing helium probe gas; and said step of sensing comprises sensing the presence of helium with a mass spectrometer.

Claim 22

The method according to claim 17, further comprising the step of introducing an outflow of probe gas to the exhaust outlet of another pump supporting the molecular drag pump, whereby gross leaks may be detected.