GB2327766A - Leak detection apparatus - Google Patents
Leak detection apparatus Download PDFInfo
- Publication number
- GB2327766A GB2327766A GB9715843A GB9715843A GB2327766A GB 2327766 A GB2327766 A GB 2327766A GB 9715843 A GB9715843 A GB 9715843A GB 9715843 A GB9715843 A GB 9715843A GB 2327766 A GB2327766 A GB 2327766A
- Authority
- GB
- United Kingdom
- Prior art keywords
- chamber
- component
- gas
- test
- helium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000001514 detection method Methods 0.000 title description 6
- 238000012360 testing method Methods 0.000 claims abstract description 65
- 239000007789 gas Substances 0.000 claims abstract description 50
- 239000001307 helium Substances 0.000 claims abstract description 45
- 229910052734 helium Inorganic materials 0.000 claims abstract description 45
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims abstract description 45
- 238000004519 manufacturing process Methods 0.000 claims abstract description 5
- 239000000203 mixture Substances 0.000 claims abstract description 5
- 230000001105 regulatory effect Effects 0.000 claims description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- 238000005070 sampling Methods 0.000 claims description 6
- 239000012298 atmosphere Substances 0.000 claims description 4
- 238000000034 method Methods 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 230000005484 gravity Effects 0.000 claims description 2
- 238000010998 test method Methods 0.000 claims description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 5
- 238000004949 mass spectrometry Methods 0.000 description 4
- 238000011109 contamination Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
- G01M3/20—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material
- G01M3/22—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators
- G01M3/226—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators for containers, e.g. radiators
- G01M3/229—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators for containers, e.g. radiators removably mounted in a test cell
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
- G01M3/20—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material
- G01M3/202—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material using mass spectrometer detection systems
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Examining Or Testing Airtightness (AREA)
Abstract
Apparatus for detecting a fabricated component for leaks has: a gas application chamber 11 for applying helium to the component after fabrication so that some of it is held temporarily in interstice(s) of the component (if it has a gross leak), a closable test chamber 15 for receiving the component from the gas application chamber and enclosing any helium diffusing from the interstice(s) of the component for its mixture with the ambient gas in the test chamber, and a mass spectrometer 22 arranged to sample the mixed gas in the test chamber for presence of helium.
Description
LEAK DETECTION APPARATUS
The present invention relates to a leak detector, particularly though not exclusively for detection of leaks in electronic components.
Many electronic components, for instance including silicon chips, have their constituent elements contained within a plastics, ceramic or metal case or housing for instance, referred to herein as a "casing" The casing is sealed and typically contains a nitrogen atmosphere to avoid contamination and degradation of the elements in use.
The casing can leak, which defeats its object. To test for leaks, the nitrogen atmosphere includes a trace of helium. This can be tested for by evacuation of the surrounding atmosphere. If helium is detected in a test chamber; then a leak in the container can be inferred. However such a test can detect only a "fine" (but none the less serious) leak, and does not detect a "gross" leak, of such large size that the nitrogen atmosphere with its helium has all diffused from the casing. Even if all the helium has not diffused through the gross leak, the evacuation of the chamber can draw substantially all the helium from the component such that there is insufficient left to test for. Normal testing relies upon the helium leaking from the component into the test chamber only after evacuation ofthe test chamber, i.e. leaking from the component during testing.
Gross leaks can be tested for by submerging the component and watching for bubbles from it. This is unreliable.
The object of the my invention is to provide an improved method and apparatus for leak detection.
It is based on application of helium to the component so that it is held temporarily in interstice(s) of the component, which are not exposed in a component not having a gross leak, followed by enclosure of the component in a test chamber and testing for presence of helium diffusing from the interstice(s).
According to one aspect of my invention, I provide apparatus for detecting a fabricated component for leaks, the apparatus comprising:
a gas application chamber for applying detectable gas to the component after fabrication so that some of it is held temporarily in interstice(s) of the component (if it has a gross leak),
a closable test chamber for receiving the component from the gas application chamber and enclosing any detectable gas diffusing from the interstice(s) of the component for its mixture with the ambient gas in the test chamber, and
means for sampling the mixed gas in the test chamber for presence of detectable gas.
Preferably means is provided for automatic transfer of the component from the gas application chamber to the test chamber. This can be a gravity chute, exposed to the ambient atmosphere.
Conveniently the test chamber closely confines the component, minimising the air space within the chamber around the component. This increases the concentration in the air of the detectable gas carried into the test chamber in the interstice(s) of the component. It also reduces the volume to be evacuated - see below - and increases component throughput.
Preferably the sampling means includes a mass spectrometer, having its own vacuum system. A bleed between the test chamber and the chamber of the mass spectrometer allows a regulated flow from the former to the latter to be drawn by the pump. As in the preferred embodiment, I prefer to provide an additional pump for drawing the gas from the test chamber in a duct off which the bleed is branched. This duct conveniently has a throttle causing a pressure drop across it, whereby the regulated flow taken off at the branch which is downstream can be kept small.
Whilst I can anticipate that other gases may be suitable as detectable gas, I prefer to use helium.
The helium application chamber can be a pressure container in which the helium is forced under pressure into the interstices(s) of the component (if this has a leak). However, in the interests of economy, I prefer for the chamber merely to have doors which allow flow of any appreciable gas pressure, with the helium being blown at low pressure over the component.
Use of helium is convenient in testing electronic components in allowing the mass spectrometer to be utilised for a fine leak test after a gross leak has been carried out as above. For this the test chamber is pumped down to a level of vacuum such as to induce a flow - of nitrogen and helium - from within the casing. However it should be noted that my apparatus can find application in testing other components, such as castings, where gross leaks only are of interest.
According to another aspect of the invention, I provide a method of testing a component for leaks consisting in the steps of:
applying detectable gas in a gas application chamber to the component after fabrication so that some of it is held temporarily in interstice(s) of the component (if it has a gross leak),
transferring the component from the gas application chamber to a closable test chamber,
enclosing the component and any detectable gas diffusing from the interstice(s) of the component for its mixture with the ambient gas in the test chamber, and
sampling the mixed gas in the test chamber for presence of detectable gas.
To help understanding of my invention, I will now describe a preferred embodiment by way of example and with reference to the accompanying drawings, I which:
Figure 1 is a partially sectioned side view of a component to be tested;
Figure 2 is a diagrammatic view of leak detection apparatus in accordance with my invention; and
Figure 3 is a cross-sectional view of a gross leak test valve in the apparatus.
Referring to the drawings, the apparatus shown is for testing a fabricated component 1, which is an electronic circuit having a metal casing 2 of two parts 3,4 joined at a weld 5 and contact pins 6 leaving the casing via glass insulation 7. The weld can have minor imperfections or the glass can be cracked for instance such as to cause fine leaks. One of the pins can be missing or the parts of the casing can have been offered up together out of alignment such as to cause the welding discharge to overheat and melt away a part ofthe casing. These are gross leaks. An extreme case of a gross leak is total omission of the lid 4 of the casing. Prior to and during welding the component will have been filled with a helium containing nitrogen atmosphere, for fine leak testing.
In a helium application chamber 11, the fabricated component is subjected to jets of helium from nozzles 12, typically for half a second. If there is a gross leak such as at 8, the some of the helium permeates inside the casing. Even if the lid 4 is missing, helium becomes temporarily held between the elements 9 of the component and a board 10. The chamber has loosely fitting doors 13, which allow helium to escape (and air to diffuse into the chamber when the helium jets are turned off). One door is for infeed of the component and another is for its outfeed. The feed arrangements form no part of this invention and will not be described. After application of helium to the component, it is allowed to move down a chute 14 to a test chamber 15, which it enters via a hermetically sealable door 16. Travel down the chute disperses all helium from around the casing of the component, leaving only that temporarily in its interstices, with the result that this is the only helium carried into the test chamber (except in the majority of cases where the component is sealed as intended and there is helium in the enclosed nitrogen atmosphere).
On entry of the gross leak component into the test chamber 15 and closing of the door 16, the helium diffuses from the interstices and mixes with the air in the chamber, albeit at low concentration but one which is higher than the normal ambient concentration of helium.
The test chamber has three valves 17,18,19. The first 17 is a gross leak test valve, connecting the chamber to a duct 20; the second 18 is a roughing valve, connecting the chamber to a rotary vacuum pump 21; the third 19 is a fine leak test valve, connecting the chamber to a mass spectrometry leak detector 22, with its own internal vacuum system (not shown). The gross leak test valve comprises a pair of ports 23,24 respectively leading from the chamber and to the duct 20. The ports 23,24 are covered outside the chamber by a rubber diaphragm 25. A vacuum chamber 26 is arranged on the outside of the diaphragm, whereby the valve can be opened by suction of the diaphragm from the ports. The outlet port 23 has a needle valve 27 fitted in its inlet orifice for regulating flow through it. The valves 18,19 are proprietary pneumatically operated bellows valves and will not be further described.
The duct 20 leads to the mass spectrometry detector 22, via a further needle valve 28, and onto the pump 21 downstream of the roughing valve 18.
Use of the apparatus in testing for both a gross leak and a fine leak will now be described. With the component in the test chamber and the roughing and the fine leak test valves 18,19 closed, any helium escaping from a gross leak mixes with the air in the chamber. The gross leak test valve 17 is opened with the vacuum pump operating.
The helium containing air is drawn at a rate proportional to the setting of the needle valve 27 into the duct. The pumps in the mass spectrometry detector 22 are also operating, drawing a small flow regulated by the needle valve 28 into the detector.
The valves are set such that the detector's pump is able to maintain sufficient vacuum for detection of the presence of helium in the sample of the gas bled through the valve 28. For this the valve 28 is more nearly closed. If the component is one which fills the test chamber more rather than less, the valve 27 is opened less to maintain the flow for the time necessary for the mass spectrometry. It should however be noted that the chamber should be as close in dimension to that of the component, to minimise the volume of air and maximise its concentration of helium. This is because in the nature of the test relying upon traces of this low molecular weight gas still being in the interstices of the component after passage down the chute, it is advantageous for the concentration of helium to be maximised by minimising the volume of air.
If helium is detected, the component will have a gross leak.
After the gross leak test, its valve 17 is closed and the roughing valve 18 is opened. This draws out the air from the test chamber to a sufficient vacuum level by the pump 21. The roughing valve is then closed and the fine leak test valve is opened.
The test chamber is then directly open to the detector. If there is a fine leak, nitrogen with helium or pure helium, for instance in accordance with the internal atmosphere of the component, is drawn from the component and the chamber. The helium is detected if there is a fine leak.
I have noted that the apparatus is reliable in terms of helium contamination provided that the chamber is of high grade material and easily cleaned and the other components are of standard vacuum technology materials. I believe this to be because of the low - but detectable if there - levels of helium present at any time.
Claims (19)
1. Apparatus for detecting a fabricated component for leaks, the apparatus comprising:
a gas application chamber for applying detectable gas to the component after
fabrication so that some of it is held temporarily in interstice(s) of the
component (if it has a gross leak), a closable test chamber for receiving the component from the gas application
chamber and enclosing any detectable gas diffusing from the interstice(s) of
the component for its mixture with the ambient gas in the test chamber, and
means for sampling the mixed gas in the test chamber for presence of
detectable gas.
2. Apparatus as claimed in claim 1, including means for automatic transfer of the component from the gas application chamber to the test chamber.
3. Apparatus as claimed in claim 2, wherein the automatic transfer means is a gravity chute, exposed to the ambient atmosphere.
4. Apparatus as claimed in any preceding claim, wherein the test chamber is adapted to closely confine the component, minimising the air space within the chamber around the component, whereby the concentration in the air of the detectable gas carried into the test chamber in the interstice(s) of the component is increased.
5. Apparatus as claimed in any preceding claim, wherein the gas application chamber is a pressure container in which the gas can be forced under pressure into the interstices(s) of the component (if this has a leak).
6. Apparatus as claimed in anyone of claims 1 to 4, wherein the chamber includes doors which allow flow of any appreciable gas pressure, the gas application chamber being adapted to blow gas at low pressure over the component.
7. Apparatus as claimed in any preceding claim, wherein the sampling means includes:
a mass spectrometer, having a pump, and
a bleed between the test chamber and the chamber of the mass spectrometer
adapted to allow a regulated flow from the former to the latter to be drawn by
the pump.
8. Apparatus as claimed in claim 7, including an additional pump for drawing the gas from the test chamber in a duct off which the bleed is branched.
9. Apparatus as claimed in claim 8, wherein the duct has a throttle causing a pressure drop across it, whereby the regulated flow taken off at a branch which is downstream can be kept small.
10. Apparatus as claimed in claim 9, wherein the test chamber has: . a gross leak test valve, connecting the chamber to the duct,
a roughing valve, connecting the chamber to the additional pump and
a fine leak test valve, connecting the chamber to the mass spectrometer.
11. Apparatus as claimed in claim 10, wherein the gross leak test valve has a pair of ports respectively leading from the chamber and to the duct, the ports being covered outside the chamber by a rubber diaphragm and a vacuum chamber being arranged on the outside of the diaphragm, whereby the valve can be opened by suction of the diaphragm from the ports.
12. Apparatus as claimed in claim 11, wherein the port leading from the chamber has a needle valve fitted in its inlet orifice for regulating flow through it.
13. Apparatus as claimed in claim 12, the duct leads to the mass spectrometer detector, via a further needle valve, and onto the additional pump downstream of the roughing valve.
14. Apparatus as claimed in any preceding claim, wherein the apparatus is adapted to use helium as the detectable gas.
15. Apparatus for detecting a fabricated component for leaks substantially as hereinbefore described with reference to Figures 2 and 3 of the accompanying drawings.
16. A method of testing a component for leaks consisting in the steps of:
applying detectable gas in a gas application chamber to the component after
fabrication so that some of it is held temporarily in interstice(s) of the
component (if it has a gross leak),
transferring the component from the gas application chamber to a closable test
chamber,
enclosing the component and any detectable gas diffusing from the
interstice(s) of the component for its mixture with the ambient gas in the test
chamber, and
sampling the mixed gas in the test chamber for presence of detectable gas.
17. A method as claimed in claim 11, wherein the detectable gas is helium.
18. A method as claimed in claim 12, wherein an additional fine leak test is carried out in which:
the test chamber is pumped down to a level of vacuum such as to induce a
flow - of nitrogen and helium - from within the casing and
the flow is tested for presence of helium.
19. A method oftesting a component for leaks substantially as hereinbefore described with reference to Figures 2 and 3 of the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9715843A GB2327766A (en) | 1997-07-28 | 1997-07-28 | Leak detection apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9715843A GB2327766A (en) | 1997-07-28 | 1997-07-28 | Leak detection apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9715843D0 GB9715843D0 (en) | 1997-10-01 |
| GB2327766A true GB2327766A (en) | 1999-02-03 |
Family
ID=10816537
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9715843A Withdrawn GB2327766A (en) | 1997-07-28 | 1997-07-28 | Leak detection apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2327766A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1279939A3 (en) * | 2001-07-19 | 2003-10-22 | Mocon, Inc. | Apparatus for conducting leakage tests on sealed packages |
| WO2008049915A2 (en) * | 2006-10-27 | 2008-05-02 | Boehringer Ingelheim International Gmbh | Method for sterilizing a film container |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1350187A (en) * | 1972-02-01 | 1974-04-18 | Jenkins A | Method and apparatus for leak testing sealed containers |
| GB1382720A (en) * | 1971-09-24 | 1975-02-05 | Varian Associates | Leak detecting system and method for passing a measured sample of gas to a leak detector |
| GB1519499A (en) * | 1974-08-28 | 1978-07-26 | Leybold Heraeus Verwaltung | Testing articles for fluid-tightness |
| US4663963A (en) * | 1985-07-04 | 1987-05-12 | Alcatel | Machine for leak testing parts by the "penetration" method |
| US5238172A (en) * | 1991-04-19 | 1993-08-24 | Alcatel Cable | Method of detecting sealing faults in a protective tube for protecting an electrical and/or optical cable, a cable, and an installation for implementing the method |
| US5345814A (en) * | 1990-12-28 | 1994-09-13 | Whirlpool Corporation | Method and apparatus for testing vacuum insulation panel quality |
-
1997
- 1997-07-28 GB GB9715843A patent/GB2327766A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1382720A (en) * | 1971-09-24 | 1975-02-05 | Varian Associates | Leak detecting system and method for passing a measured sample of gas to a leak detector |
| GB1350187A (en) * | 1972-02-01 | 1974-04-18 | Jenkins A | Method and apparatus for leak testing sealed containers |
| GB1519499A (en) * | 1974-08-28 | 1978-07-26 | Leybold Heraeus Verwaltung | Testing articles for fluid-tightness |
| US4663963A (en) * | 1985-07-04 | 1987-05-12 | Alcatel | Machine for leak testing parts by the "penetration" method |
| US5345814A (en) * | 1990-12-28 | 1994-09-13 | Whirlpool Corporation | Method and apparatus for testing vacuum insulation panel quality |
| US5238172A (en) * | 1991-04-19 | 1993-08-24 | Alcatel Cable | Method of detecting sealing faults in a protective tube for protecting an electrical and/or optical cable, a cable, and an installation for implementing the method |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1279939A3 (en) * | 2001-07-19 | 2003-10-22 | Mocon, Inc. | Apparatus for conducting leakage tests on sealed packages |
| WO2008049915A2 (en) * | 2006-10-27 | 2008-05-02 | Boehringer Ingelheim International Gmbh | Method for sterilizing a film container |
| WO2008049915A3 (en) * | 2006-10-27 | 2009-01-08 | Boehringer Ingelheim Int | Method for sterilizing a film container |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9715843D0 (en) | 1997-10-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |