Leak detecting system and method for passing a measured sample of gas to a leak detector

Claim 2

Leak detecting apparatus comprising a first vacuum pump, first conduit means for connecting said first pump to one side of a test piece, a second vacuum pump, second conduit means connecting said second pump to said first conduit means, at least two valves in said second conduit means, said valves confining between them when closed at least one fixed volume of gas, and a leaK detector connected to said second conduit means at a position between said valves and said second pump, said at least two valves comprise a hollow valve body having a partition therein forming a valve chamber on each side of said partition, said partition having a bore therethrough which forms said at least one fixed volume, a valve head in each of said valve chambers to open and close the respective adjacent end of said bore, one portion of said second conduit means being connected to one of said valve chambers, and another portion of said second conduit means being connected to the other of said valve chambers.

Claim 3

A leak detecting method comprising the steps of exposing one side of a test piece to a test gas, pumping gas from the other side of said test piece to create a low pressure gas zone into which said test gas will pass through a leak in said test piece, collecting a fixed volume of gas in said low pressure zone including any test gas which may leak through said test piece, and then communicating said fixed volume of gas to a leak detector through substantially unrestricted passage while preventing additional gas from entering said fixed volume, whereby said detector will be quickly exposed to a known fixed volume of gas.

Claim 4

A leak detecting method comprising the steps of exposing one side of a test piece to a test gas, pumping gas from the other side of said test piece to create a low pressure gas zone into which said test gas will pass through a leak in said test piece, collecting a fixed volume of gas in said low pressure zone including any test gas which may leak through said test piece, and then communicating said fixed volume of gas to a leak detector through substantially unrestricted passage while preventing additional gas from entering said fixed volume, whereby said detector will be quickly exposed to a known fixed volume of gas.

Claim 5

A leak detecting method as claimed in claim 2 comprising collecting a second fixed volume of gas in said low pressure zone, said second fixed volume being larger than the first-mentioned fixed volume; and if said leak detector does not indicate a leak after communication with said first-mentioned fixed volume, then communicating said larger fixed volume to said leak detector while preventing additional gas from entering said larger fixed volume.

Claim 6

A leak detecting method as claimed in claim 2 in which said fixed volume of gas is collected at a preselected pressure.

Claim 7

A leak detecting method as claimed in claim 4 in which said fixed volume is expanded into said leak detector and gas is pumped out of said leak detector before and during said expansion, and said preselected pressure and fixed volume and expansion and pumping are selected so that the expanded pressure in the leak detector does not exceed 10 4 Torr.

Claim 10

The method as claimed in claim 6 in which said valve means comprise first, second and third valves in series along said conduit, said first valve being positioned toward said inlet, said second valve being positioned between said first valve and said leak detector, said third valve being positioned between said second valve and said leak detector, said small fixed volume being formed between said second and third valves, and said large fixed volume being formed between said first and second valves; said method of operating said valves comprising closing said third valve, opening said first and second valves to admit to said fixed volumes test gas which may leak through the test piece, closing said first and secOnd valves to trap gas in said fixed volumes, opening said third valve to transfer only said small fixed volume to said leak detector; and if said leak detector does not indicate a leak when exposed to said small fixed volume, then opening said second valve to transfer only said large fixed volume to said leak detector.

Claim 11

The method as claimed in claim 6 in which said valve means comprise first and second valves in series with each other, third and fourth valves in series with each other and in parallel with said first and second valves, said first valve being positioned toward said inlet, said second valve being positioned between said first valve and said leak detector, said third valve being positioned toward said inlet, said fourth valve being positioned between said third valve and said leak detector, said small fixed volume being formed between said first and second valves, and said large fixed volume being formed between said third and fourth valves; said method of operating said valves comprising closing said second and fourth valves to admit to said fixed volume test gas which may leak through the test piece, closing said first and third valves to trap gas in said fixed volumes, opening said second valve to transfer only said small fixed volume to said leak detector; and if said leak detector does not indicate a leak when exposed to said small fixed volume, then opening said fourth valve to transfer only said large fixed volume to said leak detector.

Claim 12

Leak detecting apparatus comprising conduit means having an opening to receive a test gas which may leak through a test piece, a pump having an inlet connected to said conduit means downstream of said opening, a first valve in said conduit means between said opening and said pump, a second valve in said conduit means in series between said first valve and said pump, said first and second valves having a closed position confining between them when closed a fixed volume portion along said conduit means, means forming a restricted orifice in said conduit means in series between said second valve and said pump, and a leak detector in communication with said conduit means between said second valve and said restricted orifice, said first and second valves being operable to confine between them said fixed volume portion of test gas and then communicate only said fixed volume to said leak detector.

Claim 13

Leak detecting apparatus comprising conduit means having an opening to receive a test gas which may leak through a test piece, a pump having an inlet connected to said conduit means downstream of said opening, a first valve in said conduit means between said opening and said pump, a second valve in said conduit means in series between said first valve and said pump, said first and second valves having a closed position confining between them when closed a fixed volume portion along said conduit means, means forming a restricted orifice in said conduit means in series between said second valve and said pump, and a leak detector in communication with said conduit means between said second valve and said restricted orifice, said first and second valves being operable to confine between them said fixed volume portion of test gas and then communicate only said fixed volume to said leak detector.

Claim 14

Leak detecting apparatus as claimed in claim 9 further comprising valve means forming when closed a second fixed volume portion along said conduit means, said second fixed volume portion being smaller than the first-mentioned fixed volume portion, and said valves and valve means being operable to form both of said fixed volume portions and then communicate first said smaller fixed volume and then the larger fixed volume to said leak detector.

Claim 15

Leak detecting apparatus as claimed in claim 9 further comprising a second pump, second conduit means having one end connected to the inlet of said second pump, the other end of said second conduit means being connected to the first-mentioned conduit means upstream of said first valve and downstream of said opening in said first mentioned conduit means, and a valve in said first-mentioned conduit means upstream of said first valve and upstream of the connection of said second conduit means to said first-mentioned conduit means.

Claim 16

Leak detecting apparatus comprising conduit means having an inlet to receive test gas which may leak through a test piece, a leak detector connected to said conduit means at a location spaced from said inlet, first and second valves in series with each other along said conduit means between said inlet and said leak detector, third and fourth valves along said conduit means between said inlet and said leak detector, said third and fourth valves being in series with each other and in parallel with said first and second valves, said first and second valves confining a fixed volume between them when closed, said third and fourth valves confining between them when closed a fixed volume which is larger then the first-mentioned fixed volume, and said valves being operable to trap gas in said fixed volumes and then transfer only said fixed volumes of gas in sequence to said leak detector starting with the smaller fixed volume.

Claim 17

Leak detecting apparatus comprising conduit means having an inlet to receive test gas which may leak through a test piece, a leak detector connected to said conduit means at a location spaced from said inlet, first and second valves in series with each other along said conduit means between said inlet and said leak detector, third and fourth valves along said conduit means between said inlet and said leak detector, said third and fourth valves being in series with each other and in parallel with said first and second valves, said first and second valves confining a fixed volume between them when closed, said third and fourth valves confining between them when closed a fixed volume which is larger then the first-mentioned fixed volume, and said valves being operable to trap gas in said fixed volumes and then transfer only said fixed volumes of gas in sequence to said leak detector starting with the smaller fixed volume.

Claim 18

Leak detecting apparatus comprising conduit means having an inlet to receive test gas which leaks through a test piece, a leak detector connected to said conduit means at a location spaced from said inlet, two valves in series along said conduit means between said inlet and said leak detector, said valves forming between them when closed a fixed volume in said conduit means, said conduit means having immovable walls everywhere along the portion forming said fixed volume between said valves, both said valves being fully closable, and the valve which is nearest said leak detector being quickly operable between fully open and fully closed position to provide a substantially instantaneous full communication between said fixed volume and said leak detector.

Claim 19

Leak detecting apparatus comprising conduit means having an inlet to receive test gas which leaks through a test piece, a leak detector connected to said conduit means at a location spaced from said inlet, two valves in series along said conduit means between said inlet and said leak detector, said valves forming between them when closed a fixed volume in said conduit means, said conduit means having immovable walls everywhere along the portion forming said fixed volume between said valves, both said valves being fully closable, and the valve which is nearest said leak detector being quickly operable between fully open and fully closed position to provide a substantially instantaneous full communication between said fixed volume and said leak detector.

Claim 20

Leak detecting apparatus as claimed in claim 13 further comprising vacuum pumping means for evacuating said conduit means on its inlet side of the one of said valves which is nearest said leak detector, said pumping means being adapted to perform said evacuation when said one valve is in closed position.

Claim 21

A leak detection method comprising the steps of presenting a test gas atmosphere to one side of a test piece, and exposing the other side of said test piece to an evacuable test zone, connecting a vacuum pump to said test zone while said other side of said test piece is in communication with said test zone to create a low pressure gas region into which said test gas will pass through a leak in said test piece, then collecting a fixed volume of gas in said low pressure region including any test gas which may leak through said test piece, and then communicating said fixed volume of gas to a leak detector while preventing additional gas from entering said fixed volume.

Claim 22

A leak detection method comprising the steps of presenting a test gas atmosphere to one side of a test piece, and exposing the other side of said test piece to an evacuable test zone, connecting a vacuum pump to said test zone while said other side of said test piece is in communication with said test zone to create a low pressure gas region into which said test gas will pass through a leak in said test piece, then collecting a fixed volume of gas in said low pressure region including any test gas which may leak through said test piece, and then communicating said fixed volume of gas to a leak detector while preventing additional gas from entering said fixed volume.

Claim 23

A leak detecting method as claimed in claim 15 in which said fixed volume of gas is communicated to said leak detector through a substantially unrestricted passage.

Claim 24

A leak detecting method as claimed in claim 15 further comprising pumping gas out of said leak detector, and collecting gas in said fixed volume at a preselected pressure; said preselected pressure, size of said fixed volume, and rate of pumping gas out of said leak detector be selected to create a pressure of less than 10 4 Torr in said leak detector before said fixed volume is transmitted to said detector and permit the pressure in the leak detector to increase when said fixed volume of gas at said preselected pressure is transmitted to the leak detector, and said increased pressure being a pressure of less than 10 3 Torr.

Claim 25

Leak detecting apparatus comprising conduit means having an inlet to receive test gas which may leak through a test piece; a leak detector connected to said conduit means at a location spaced from said inlet; first, second, and third valves connected in that order in series with each other along said conduit means between said inlet and said leak detector, with said first valve being nearest said inlet; said second and third valves confining a first fixed volume between them when closed; said first and second valves confining between them when closed a second fixed volume which is larger than said first fixed volume; vacuum pump means connected to said apparatus for evacuating said conduit means on the leak detector side of said third valve even when said third valve is closed and for evacuating said conduit means on the inlet side of said first valve even when said first valve is closed, and a fourth valve in series between said first valve and said pump means for evacuating the inlet side of said first valve.

Claim 26

Leak detecting apparatus comprising conduit means having an inlet to receive test gas which may leak through a test piece; a leak detector connected to said conduit means at a location spaced from said inlet; first, second, and third valves connected in that order in series with each other along said conduit means between said inlet and said leak detector, with said first valve being nearest said inlet; said second and third valves confining a first fixed volume between them when closed; said first and second valves confining between them when closed a second fixed volume which is larger than said first fixed volume; vacuum pump means connected to said apparatus for evacuating said conduit means on the leak detector side of said third valve even when said third valve is closed and for evacuating said conduit means on the inlet side of said first valve even when said first valve is closed, and a fourth valve in series between said first valve and said pump means for evacuating the inlet side of said first valve.

Claim 27

Leak detecting apparatus comprising conduit means having an inlet to receive test gas which may leak through a test piece, a leak detector communicating with said conduit means at a location spaced from said inlet, means along said conduit means for collecting two different size fixed volumes of gas received from said inlet and for transmitting only the smaller of said fixed volumes of gas to said leak detector and then transmitting only the larger of said fixed volumes to said leak detector, vacuum pump means for evacuating said conduit means from the inlet side of said collecting means and from the leak detector side of said collecting means, pressure indicating means communicating with said conduit means to permit collecting said fixed volumes of gas at a preselected pressure, and valve means between the inlet side of said collecting means and said pump means for evacuating the conduit means on the inlet side of said collecting means.

Claim 28

Leak detecting apparatus comprising conduit means having an inlet to receive test gas which may leak through a test piece, a leak detector communicating with said conduit means at a location spaced from said inlet, means along said conduit means for collecting two different size fixed volumes of gas received from said inlet and for transmitting only the smaller of said fixed volumes of gas to said leak detector and then transmitting only the larger of said fixed volumes to said leak detector, vacuum pump means for evacuating said conduit means from the inlet side of said collecting means and from the leak detector side of said collecting means, pressure indicating means communicating with said conduit means to permit collecting said fixed volumes of gas at a preselected pressure, and valve means between the inlet side of said collecting means and said pump means for evacuating the conduit means on the inlet side of said collecting means.

Claim 29

Leak detecting apparatus as claimed in claim 19 in which said leak detector is a mass spectrometer leak detector.

Claim 30

Leak detecting apparatus as claimed in claim 19 in which said valve means comprises a valve and a restricted orifice by-pass around said valve.