US20020001462A1 - Leakage detector for a sealed housing - Google Patents
Leakage detector for a sealed housing Download PDFInfo
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- US20020001462A1 US20020001462A1 US09/927,094 US92709401A US2002001462A1 US 20020001462 A1 US20020001462 A1 US 20020001462A1 US 92709401 A US92709401 A US 92709401A US 2002001462 A1 US2002001462 A1 US 2002001462A1
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- sub
- chamber
- case
- environment
- plug
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B17/00—Details of cameras or camera bodies; Accessories therefor
- G03B17/18—Signals indicating condition of a camera member or suitability of light
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B17/00—Details of cameras or camera bodies; Accessories therefor
- G03B17/02—Bodies
- G03B17/08—Waterproof bodies or housings
Definitions
- This invention relates to the detection of leakage in a casing based on sensing changes in the air pressure.
- Airtight or waterproof cases are used to enclose cameras and other sensitive apparatus to protect them from their operating environment external to the case (herein “environment”), which may have moisture, dust, gases and other harmful elements. Cases may suffer from manufacturing defects and may consequently leak.
- Hayakawa U.S. Pat. No. 5,305,031
- the means for increasing the air pressure and detecting changes is itself a potential source of leakage in addition to possible leakage in the casing.
- Takamura U.S. Pat. No. 4,763,145
- Prager DE 38 37 624 are further examples wherein differential pressure of sub-chambers is used to detect leaks, however not all of such sub-chambers are in communication with the environment.
- this invention provides a case comprising: (a) sealed housing with an outer wall; and (b) a leakage detector firmly located in said wall having: (i) a chamber with first and secondsub-chambers; (ii) first port means by which said first sub-chamber communicates with the environment; (iii) second port means by which said second sub-chamber communicates with the environment; (iv) a partition separating said first sub-chamber from said second sub-chamber which moves in response to the difference in the respective air pressures of said first and second sub-chamber; and (v) indicator means, located proximate said partition and responsive to movement of said partition, for indicating leakage.
- this invention provides a leakage detector for a sealed housing with an outer wall, comprising: (i) a chamber with first and second sub-chambers; (ii) first port means by which said first sub-chamber communicates with the environment; (iii) second port means by which said second sub-chamber communicates with the environment; (iv) a partition separating said first sub-chamber from said second sub-chamber which moves in response to the difference in the respective air pressures of said first and second sub-chamber; and (v) indicator means, located proximate said partition and responsive to movement of said partition, for indicating leakage.
- this invention provides a method of detecting leakage in a case, comprising the steps of: (a) creating a first sub-chamber of pressurized air in communication with the interior of the case; (b) creating a second sub-chamber of air; (c) abutting a portion of said first sub-chamber with a portion of said second sub-chamber where the abutment is in the form of a membrane whose profile changes in response to the relative differences in air pressures of said first and second sub-chambers.
- FIG. 1 is a rear perspective view of an underwater camera housing employing a leakage detector according to the present invention
- FIG. 2 is a perspective view of the leakage detector according to the present invention.
- FIG. 3( a ) is a top view of the detector of FIG. 2;
- FIG. 3( b ) is a side view of the detector of FIG. 3( a ) taken along line II-II therein;
- FIG. 4( a ) is a top view of the injector head of the present invention.
- FIG. 4( b ) is a side view of the injector head of FIG. 4( a ) taken along line II-II therein;
- FIG. 5( a ) is a top view of the plug of the present invention.
- FIG. 5( b ) is a side view of the plug of FIG. 5( a ) taken along line II-II therein;
- FIG. 6 is a side view of the injector head inserted into the detector according to another embodiment
- FIG. 7 is a side view of the plug inserted into the detector
- FIG. 8 is a perspective view of the leakage detector according to the present invention.
- FIG. 9( a ) is a top view of the detector of FIG. 8;
- FIG. 9( b ) is a side view of the detector of FIG. 9( a ) taken along line II-II therein;
- FIG. 10( a ) is a top view of the injector head of the present invention.
- FIG. 10( b ) is a side view of the injector head of FIG. 10( a ) taken along line II-II therein;
- FIG. 11( a ) is a top view of the plug of the present invention.
- FIG. 11 ( b ) is a side view of the plug of FIG. 11( a ) taken along line II-II therein;
- FIG. 12 is a side view of the injector head inserted into the detector
- FIG. 13 is a side view of the plug inserted into the detector
- FIGS. 14 a to 14 f are side and top views of an alternative embodiment of the invention.
- FIG. 1 shows underwater camera housing 10 , which has front part 10 a and rear part 10 b held together by several spring-loaded latches (one, 10 c , is shown in FIG. 1). Silicon or rubber O-ring 10 d provides a waterproof seal between front and rear parts 10 a and 10 b when latched together.
- Leakage detector 20 is connected to housing 10 at hole 15 in rear part 10 b (explained below). Leakage detector 20 has several purposes, in addition to detecting leakage. To pressurize the air in housing 10 , plastic hand or finger pump 99 , is employable with leakage detector 20 through injector head 40 . Leakage detector 20 is plugged with plug 50 .
- detector 20 has a convex, annular upper body 21 with a central port 23 to receive injector head 40 or plug 50 (explained below), and a hollow stem 22 depending downwardly.
- Stem 22 and hole 15 are respectively profiled to create a tight friction fit when stem 22 is inserted in hole 15 and the connection is conventionally sealed with glue, O-rings and ultrasonically bonded.
- the base of body 21 is profiled to hug rear part 10 b in a flush manner.
- Body 21 has three sockets 27 which interact with corresponding wings 28 of injector head 40 or plug 50 (explained below) to create a tight interlock therewith.
- elastic membrane 25 (explained below) and the portion of body 21 proximate membrane 25 is transparent and has a visible scale of graduations 26 to permit viewing of the profile of membrane 25 relative thereto (as shown in FIG. 2).
- Body 21 has atmospheric sub-chamber 30 , in the shape of a partial torus, in communication with the environment by sub-chamber port 31 and detector central port 23 .
- Body 21 has pressurized sub-chamber 32 , in the shape of a partial torus, in communication with the interior of housing 10 through stem 22 .
- Detector central port 23 communicates with sub-chamber 32 by a one-way valve 24 .
- Atmospheric sub-chamber 30 is separated from pressurized sub-chamber 32 by flexible membrane 25 . As the air pressure in sub-chamber 32 increases above atmospheric pressure, the profile of membrane 25 will change. From an initial flat profile, membrane 25 will curve or bulge inwardly into atmospheric sub-chamber 30 .
- the profile of membrane 25 is visible to the user through the transparent portion of body 21 relative to graduations 26 thereon.
- One particular graduation may signify the appropriate pressure for testing particular housing 10 .
- the graduations are usable as visual markers and the exact significance of any particular graduation can be determined by the user based on the particular housing being tested.
- Injector head 40 as shown in FIG. 4, has O-ring 41 and three equi-spaced wings 28 which interact with corresponding sockets 27 of detector 20 for a bayonet or similar type secured interlock with detector central port 23 .
- Plug 50 has a bottom protuberance 51 , upper O-ring 42 and lower O-ring 43 , and three equi-spaced wings 28 which interact with corresponding sockets 27 of detector 20 for a bayonet or similar type interlock with detector central port 23 .
- Upper O-ring 42 and lower O-ring 43 are disposed on plug 50 such that when plug 50 is inserted and secured in detector central port 23 , upper O-ring 42 and lower O-ring 43 bracket sub-chamber port 31 .
- Protuberance 51 is located on plug 50 so that when plug 50 is inserted and secured in detector central 23 , protuberance 51 pushes down and thereby opens valve 24 to permit air from pressurized sub-chamber 32 to enter detector central port 23 .
- Plug 50 also has a gripping means 55 , which may be a coin slot or plastic handle which the user may easily manipulate to insert and secure the wing-socket interlock mentioned above.
- the user drills a hole in housing 10 rear part 10 b with a suitable profile to accept stem 22 of detector 20 in a tight friction fit (and sealed as described above); inserts detector 20 and then inserts injector head 40 into detector central port 23 .
- O-ring 41 is disposed below sub-chamber port 31 so that atmospheric sub-chamber 30 is in direct communication with the environment.
- air is forced through valve 24 , into sub-chamber 32 and then into the interior of housing 10 .
- the resulting increased air pressure will tend to create a curved profile of membrane 25 and the extent of curve will be visible to the user relative to graduations 26 .
- the user will stop pressurizing at a suitable pressure level (after considering the movement of membrane 25 relative to graduations 26 , membrane 25 will have its initial profile), withdraw injector head 40 , and insert and insert and secure plug 50 in detector central port 23 , as shown in FIG. 7.
- a suitable pressure level (after considering the movement of membrane 25 relative to graduations 26 , membrane 25 will have its initial profile), withdraw injector head 40 , and insert and insert and secure plug 50 in detector central port 23 , as shown in FIG. 7.
- the user will observe if membrane 25 changes its initial curved profile. If there is leakage in housing 10 , the air pressure in pressurized sub-chamber 32 will decrease and the curved profile will flatten.
- a suitable period to observe for changes depends on factors like the confidence level sought by the user.
- valve 24 allows pressurized air from pressurized sub-chamber 32 to move into the tiny cracks between plug 50 and proximate portions of detector central port 23 which are circumscribed from above by lower O-ring 43 . If the seal created by lower O-ring 43 leaks, air will escape through sub-chamber port 31 into atmospheric sub-chamber 30 . The result will be a decrease in pressure in sub-chamber 32 and a corresponding change in profile of membrane 25 can be detected by the user. In such a condition, even if the seal of upper O-ring 42 was sufficient to prevent leakage, a change in the profile of membrane 25 would be interpreted as a warning to the user to consider replacing plug 50 because lower O-ring 43 had failed. Also, although atmospheric sub-chamber 30 is typically in communication with the atmosphere during testing for leakage, the operating environment of detector 20 in housing 10 typically has hostile elements and therefore, atmospheric sub-chamber 30 is advantageously sealed therefrom by upper O-ring 42 .
- the profile of membrane 25 that indicates the absence of leakage i.e. the constancy of the profile from the initial curve of membrane 25
- suitable corrective action can be taken. For example, during the quality checking process as the last step in the manufacture of housings, a particular housing 10 which leaked can be rejected or returned for correction.
- housing 10 equipped with detector 20 After successful manufacture and testing (e.g. while it is stored in inventory or being transported), housing 10 equipped with detector 20 provides continuous detection of leakage, whether of housing 10 or plug 50 .
- housing 10 for a camera may be dimensioned 6′′ ⁇ 4′′ ⁇ 2′′ and made of polycarbonate.
- Detector 20 may be dimensioned 1′′ in diameter and body may be 2′′ in height and made mainly of polycarbonate.
- Sub-chamber 30 may be a part toroidal-shaped cylinder with one end closed and the other end open.
- Sub-chamber 32 may be similarly constructed.
- Sub-chambers 30 and 32 are joined at their open ends and separated by membrane 25 , which may a sheet of elastic material covering one open end and sealed conventionally.
- Membrane 25 may be made of such elastic material and dimensions, and secured in place, as are appropriate for the particular application but in any case, membrane 25 must be sufficiently strong to provide an air tight separation between sub-chambers 30 and 32 even while being sufficiently flexible to bulge without undue air pressure.
- membrane 25 may be latex rubber or silicon sheet which is bracketed conventionally over the open end of pressurized sub-chamber 32 .
- Membrane 25 and its connection should be able to withstand pressure up to 8 psi for testing housing 10 for a typical camera.
- Valve 24 may be a conventional silicon or rubber one-way valve but biasing on springs or other conventional means are possible as long as the self-closing sealing action is quick.
- FIGS. 8 - 13 A second embodiment of the invention, as shown in FIGS. 8 - 13 , is very similar to the first embodiment shown in FIGS. 1 - 7 .
- reference numerals which are identical to those in FIGS. 1 - 7 represent similar or identical elements.
- atmospheric sub-chamber 30 is separated from pressurized sub-chamber 32 by oil drop 125 .
- the indication of leakage created by the movement of flexible membrane 25 in the first embodiment is replaced with the indication of leakage created by the movement of oil drop 125 within transparent tube 126 which is itself disposed within a proximate, transparent portion of body 21 to permit viewing of the location of oil drop 125 .
- Tube 1 26 is conventional and is at most 1 millimeter in diameter.
- Oil drop 125 is conventional industrial oil (as can be obtained from suppliers like Texaco) having attributes of low viscosity, non-vaporizing, and surface cohesion appropriate for the detection of a pressure leak according to this invention.
- Injector head 140 is the same as injector head 40 but has an additional cross bars 28 a at the bottom thereof, as shown in FIG. 10.
- Plug 150 (unlike plug 50 as shown in FIG. 5) has no bottom protuberance.
- Valve 124 (unlike valve 24 as shown in FIGS. 3 , 6 , 7 ), is a conventional one-way valve, spring biased into the closed postion. Valve abutment 124 a protrudes above the floor of central port 23 in closed position. Valve 124 is opened by the downward pressing against valve abutment 124 a by cross-bars 28 a of injector head 140 (as shown in FIG. 12) or by plug 150 (as shown in FIG. 13).
- Valve 124 may be a conventional silicon or rubber one-way valve biased in the closed position by quickly acting springs. Other conventional means are possible as long as the self-closing sealing action is quick.
- FIGS. 14 a to 14 f instead of using pump 99 to force air into sub-chamber 32 , pump 99 is used to withdraw air from sub-chamber 32 .
- membrane 25 will change its curved profile in the opposite direction as in the case where air is forced into sub-chamber 32 .
- a spring loaded valve 61 is used that is biased in the closed position. Such a valve 61 is useful for either when air is pumped into sub-chamber 32 or when air is withdrawn from sub-chamber 32 .
- Alternative means of displaying pressure differences between sub-chambers 30 , 32 include an LED display coupled with a pressure sensor or a spring loaded bellows.
Abstract
To test the integrity of waterproof cases for cameras and like apparatus to be used underwater, a casing with a detector is provided. The air inside the casing is pressurized and the detector indicates leakage based on the difference between the pressurized air and atmospheric pressure. A decrease in pressure of the initial level of pressurized air implies leakage.
Description
- This application is a continuation-in-part of international application number PCT CA99/00122, filed Feb. 9, 1999 which is a continuation-in-part of U.S. patent application Ser. No. 08/819,339 (issued as U.S. Pat. No. 5,870,632).
- This invention relates to the detection of leakage in a casing based on sensing changes in the air pressure.
- Airtight or waterproof cases are used to enclose cameras and other sensitive apparatus to protect them from their operating environment external to the case (herein “environment”), which may have moisture, dust, gases and other harmful elements. Cases may suffer from manufacturing defects and may consequently leak.
- Detection of leaks in supposedly waterproof cases has been conventionally attempted by detecting the presence of moisture. Schwomma (U.S. Pat. No. 4,312,580) is a representative example. Not only are moisture detectors difficult and expensive to build and maintain, the detection of moisture comes often too late (e.g. moisture has already entered the casing).
- As well, detection of leaks has been conventionally attempted by observing changes in the air pressure inside the casing after artificially increasing it. Hayakawa (U.S. Pat. No. 5,305,031) is a representative example. One defect of such attempts is that the means for increasing the air pressure and detecting changes, is itself a potential source of leakage in addition to possible leakage in the casing. For example, after using the Hayakawa device to test the integrity of the casing, it is neither clear that the “self-closing” seal will maintain its integrity nor how to test for that post-testing integrity. Takamura (U.S. Pat. No. 4,763,145) and Prager (DE 38 37 624) are further examples wherein differential pressure of sub-chambers is used to detect leaks, however not all of such sub-chambers are in communication with the environment.
- To address the above defects with the conventional approaches, this invention provides a case comprising: (a) sealed housing with an outer wall; and (b) a leakage detector firmly located in said wall having: (i) a chamber with first and secondsub-chambers; (ii) first port means by which said first sub-chamber communicates with the environment; (iii) second port means by which said second sub-chamber communicates with the environment; (iv) a partition separating said first sub-chamber from said second sub-chamber which moves in response to the difference in the respective air pressures of said first and second sub-chamber; and (v) indicator means, located proximate said partition and responsive to movement of said partition, for indicating leakage.
- To address the above defects with the conventional approaches, this invention provides a leakage detector for a sealed housing with an outer wall, comprising: (i) a chamber with first and second sub-chambers; (ii) first port means by which said first sub-chamber communicates with the environment; (iii) second port means by which said second sub-chamber communicates with the environment; (iv) a partition separating said first sub-chamber from said second sub-chamber which moves in response to the difference in the respective air pressures of said first and second sub-chamber; and (v) indicator means, located proximate said partition and responsive to movement of said partition, for indicating leakage.
- To address the above defects with the conventional approaches, this invention provides a method of detecting leakage in a case, comprising the steps of: (a) creating a first sub-chamber of pressurized air in communication with the interior of the case; (b) creating a second sub-chamber of air; (c) abutting a portion of said first sub-chamber with a portion of said second sub-chamber where the abutment is in the form of a membrane whose profile changes in response to the relative differences in air pressures of said first and second sub-chambers.
- Advantages of the present invention will become apparent from the following detailed description taken in conjunction with preferred embodiments shown in the accompanying drawings, in which:
- FIG. 1 is a rear perspective view of an underwater camera housing employing a leakage detector according to the present invention;
- FIG. 2 is a perspective view of the leakage detector according to the present invention;
- FIG. 3(a) is a top view of the detector of FIG. 2;
- FIG. 3(b) is a side view of the detector of FIG. 3(a) taken along line II-II therein;
- FIG. 4(a) is a top view of the injector head of the present invention;
- FIG. 4(b) is a side view of the injector head of FIG. 4(a) taken along line II-II therein;
- FIG. 5(a) is a top view of the plug of the present invention;
- FIG. 5(b) is a side view of the plug of FIG. 5(a) taken along line II-II therein;
- FIG. 6 is a side view of the injector head inserted into the detector according to another embodiment;
- FIG. 7 is a side view of the plug inserted into the detector;
- FIG. 8 is a perspective view of the leakage detector according to the present invention;
- FIG. 9(a) is a top view of the detector of FIG. 8;
- FIG. 9(b) is a side view of the detector of FIG. 9(a) taken along line II-II therein;
- FIG. 10(a) is a top view of the injector head of the present invention;
- FIG. 10(b) is a side view of the injector head of FIG. 10(a) taken along line II-II therein;
- FIG. 11(a) is a top view of the plug of the present invention;
- FIG. 11 (b) is a side view of the plug of FIG. 11(a) taken along line II-II therein;
- FIG. 12 is a side view of the injector head inserted into the detector;
- FIG. 13 is a side view of the plug inserted into the detector;
- FIGS. 14a to 14 f are side and top views of an alternative embodiment of the invention.
- FIG. 1 shows
underwater camera housing 10, which hasfront part 10 a andrear part 10 b held together by several spring-loaded latches (one, 10 c, is shown in FIG. 1). Silicon or rubber O-ring 10 d provides a waterproof seal between front andrear parts Leakage detector 20 is connected tohousing 10 athole 15 inrear part 10 b (explained below).Leakage detector 20 has several purposes, in addition to detecting leakage. To pressurize the air inhousing 10, plastic hand orfinger pump 99, is employable withleakage detector 20 throughinjector head 40.Leakage detector 20 is plugged withplug 50. - As shown in FIGS. 2 and 3,
detector 20 has a convex, annularupper body 21 with acentral port 23 to receiveinjector head 40 or plug 50 (explained below), and ahollow stem 22 depending downwardly.Stem 22 andhole 15 are respectively profiled to create a tight friction fit whenstem 22 is inserted inhole 15 and the connection is conventionally sealed with glue, O-rings and ultrasonically bonded. The base ofbody 21 is profiled to hugrear part 10 b in a flush manner.Body 21 has threesockets 27 which interact withcorresponding wings 28 ofinjector head 40 or plug 50 (explained below) to create a tight interlock therewith. Withinbody 21 is elastic membrane 25 (explained below) and the portion ofbody 21proximate membrane 25 is transparent and has a visible scale ofgraduations 26 to permit viewing of the profile ofmembrane 25 relative thereto (as shown in FIG. 2). -
Body 21 hasatmospheric sub-chamber 30, in the shape of a partial torus, in communication with the environment bysub-chamber port 31 and detectorcentral port 23.Body 21 has pressurizedsub-chamber 32, in the shape of a partial torus, in communication with the interior ofhousing 10 throughstem 22. Detectorcentral port 23 communicates withsub-chamber 32 by a one-way valve 24.Atmospheric sub-chamber 30 is separated from pressurizedsub-chamber 32 byflexible membrane 25. As the air pressure insub-chamber 32 increases above atmospheric pressure, the profile ofmembrane 25 will change. From an initial flat profile,membrane 25 will curve or bulge inwardly intoatmospheric sub-chamber 30. The profile ofmembrane 25, and in particular the crown of a bulged profile, is visible to the user through the transparent portion ofbody 21 relative tograduations 26 thereon. One particular graduation may signify the appropriate pressure for testingparticular housing 10. Generally, the graduations are usable as visual markers and the exact significance of any particular graduation can be determined by the user based on the particular housing being tested. -
Injector head 40, as shown in FIG. 4, has O-ring 41 and three equi-spacedwings 28 which interact withcorresponding sockets 27 ofdetector 20 for a bayonet or similar type secured interlock with detectorcentral port 23. -
Plug 50, as shown in FIG. 5, has abottom protuberance 51, upper O-ring 42 and lower O-ring 43, and three equi-spacedwings 28 which interact withcorresponding sockets 27 ofdetector 20 for a bayonet or similar type interlock with detectorcentral port 23. Upper O-ring 42 and lower O-ring 43 are disposed onplug 50 such that whenplug 50 is inserted and secured in detectorcentral port 23, upper O-ring 42 and lower O-ring 43bracket sub-chamber port 31.Protuberance 51 is located onplug 50 so that whenplug 50 is inserted and secured in detector central 23,protuberance 51 pushes down and thereby opensvalve 24 to permit air from pressurized sub-chamber 32 to enter detectorcentral port 23. - Plug50 also has a gripping
means 55, which may be a coin slot or plastic handle which the user may easily manipulate to insert and secure the wing-socket interlock mentioned above. - As shown in FIG. 6, the user drills a hole in
housing 10rear part 10 b with a suitable profile to acceptstem 22 ofdetector 20 in a tight friction fit (and sealed as described above);inserts detector 20 and then insertsinjector head 40 into detectorcentral port 23. O-ring 41 is disposed belowsub-chamber port 31 so thatatmospheric sub-chamber 30 is in direct communication with the environment. By user manipulation ofpump 99, air is forced throughvalve 24, intosub-chamber 32 and then into the interior ofhousing 10. The resulting increased air pressure will tend to create a curved profile ofmembrane 25 and the extent of curve will be visible to the user relative tograduations 26. The user will stop pressurizing at a suitable pressure level (after considering the movement ofmembrane 25 relative tograduations 26,membrane 25 will have its initial profile), withdrawinjector head 40, and insert and insert andsecure plug 50 in detectorcentral port 23, as shown in FIG. 7. The user will observe ifmembrane 25 changes its initial curved profile. If there is leakage inhousing 10, the air pressure inpressurized sub-chamber 32 will decrease and the curved profile will flatten. A suitable period to observe for changes depends on factors like the confidence level sought by the user. - The opening of
valve 24 by protuberance 51 (as explained above) allows pressurized air from pressurized sub-chamber 32 to move into the tiny cracks betweenplug 50 and proximate portions of detectorcentral port 23 which are circumscribed from above by lower O-ring 43. If the seal created by lower O-ring 43 leaks, air will escape throughsub-chamber port 31 intoatmospheric sub-chamber 30. The result will be a decrease in pressure insub-chamber 32 and a corresponding change in profile ofmembrane 25 can be detected by the user. In such a condition, even if the seal of upper O-ring 42 was sufficient to prevent leakage, a change in the profile ofmembrane 25 would be interpreted as a warning to the user to consider replacingplug 50 because lower O-ring 43 had failed. Also, althoughatmospheric sub-chamber 30 is typically in communication with the atmosphere during testing for leakage, the operating environment ofdetector 20 inhousing 10 typically has hostile elements and therefore,atmospheric sub-chamber 30 is advantageously sealed therefrom by upper O-ring 42. - Thus it is seen that beyond naturally doubling the integrity of the seal of
plug 50, having a pair of O-rings - The profile of
membrane 25 that indicates the absence of leakage (i.e. the constancy of the profile from the initial curve of membrane 25) will be present only if there is no leakage inhousing 10 and no leakage indetector 20. Upon detection of leakage, suitable corrective action can be taken. For example, during the quality checking process as the last step in the manufacture of housings, aparticular housing 10 which leaked can be rejected or returned for correction. After successful manufacture and testing (e.g. while it is stored in inventory or being transported),housing 10 equipped withdetector 20 provides continuous detection of leakage, whether ofhousing 10 or plug 50. - For example,
housing 10 for a camera may be dimensioned 6″×4″×2″ and made of polycarbonate.Detector 20 may be dimensioned 1″ in diameter and body may be 2″ in height and made mainly of polycarbonate. - Sub-chamber30 may be a part toroidal-shaped cylinder with one end closed and the other end open. Sub-chamber 32 may be similarly constructed. Sub-chambers 30 and 32 are joined at their open ends and separated by
membrane 25, which may a sheet of elastic material covering one open end and sealed conventionally.Membrane 25 may be made of such elastic material and dimensions, and secured in place, as are appropriate for the particular application but in any case,membrane 25 must be sufficiently strong to provide an air tight separation betweensub-chambers membrane 25 may be latex rubber or silicon sheet which is bracketed conventionally over the open end ofpressurized sub-chamber 32.Membrane 25 and its connection should be able to withstand pressure up to 8 psi for testinghousing 10 for a typical camera. -
Valve 24 may be a conventional silicon or rubber one-way valve but biasing on springs or other conventional means are possible as long as the self-closing sealing action is quick. - A second embodiment of the invention, as shown in FIGS.8-13, is very similar to the first embodiment shown in FIGS. 1-7. In FIGS. 8-13, reference numerals which are identical to those in FIGS. 1-7 represent similar or identical elements.
- In contrast to the first embodiment, in the second embodiment,
atmospheric sub-chamber 30 is separated frompressurized sub-chamber 32 byoil drop 125. In effect, the indication of leakage created by the movement offlexible membrane 25 in the first embodiment is replaced with the indication of leakage created by the movement ofoil drop 125 withintransparent tube 126 which is itself disposed within a proximate, transparent portion ofbody 21 to permit viewing of the location ofoil drop 125.Tube 1 26 is conventional and is at most 1 millimeter in diameter.Oil drop 125 is conventional industrial oil (as can be obtained from suppliers like Texaco) having attributes of low viscosity, non-vaporizing, and surface cohesion appropriate for the detection of a pressure leak according to this invention. -
Injector head 140 is the same asinjector head 40 but has an additional cross bars 28 a at the bottom thereof, as shown in FIG. 10. - Plug150 (unlike
plug 50 as shown in FIG. 5) has no bottom protuberance. - Valve124 (unlike
valve 24 as shown in FIGS. 3,6,7), is a conventional one-way valve, spring biased into the closed postion. Valve abutment 124 a protrudes above the floor ofcentral port 23 in closed position.Valve 124 is opened by the downward pressing against valve abutment 124 a by cross-bars 28 a of injector head 140 (as shown in FIG. 12) or by plug 150 (as shown in FIG. 13). -
Valve 124 may be a conventional silicon or rubber one-way valve biased in the closed position by quickly acting springs. Other conventional means are possible as long as the self-closing sealing action is quick. - In a third embodiment, as shown in FIGS. 14a to 14 f, instead of using
pump 99 to force air intosub-chamber 32, pump 99 is used to withdraw air fromsub-chamber 32. In thisembodiment membrane 25 will change its curved profile in the opposite direction as in the case where air is forced intosub-chamber 32. As shown in the FIGS. 14a to 14 f, a spring loadedvalve 61 is used that is biased in the closed position. Such avalve 61 is useful for either when air is pumped intosub-chamber 32 or when air is withdrawn fromsub-chamber 32. - Alternative means of displaying pressure differences between sub-chambers30, 32 include an LED display coupled with a pressure sensor or a spring loaded bellows.
- It will be appreciated that the dimensions given are merely for purposes of illustration and are not limiting in any way. The specific dimensions given may be varied in practising this invention, depending on the specific application.
Claims (22)
1. A case comprising:
(a) sealed housing (10) with an outer wall; and
(b) a leakage detector (20) firmly located in said wall having:
(i) a chamber with first and second sub-chambers (30, 32);
(ii) first port means (31) by which said first sub-chamber (30) communicates with the environment;
(iii) second port means (23) by which said second sub-chamber communicates with the environment;
(iv) a partition (25) separating said first sub-chamber from said second sub-chamber which moves in response to the difference in the respective air pressures of said first and second sub-chamber (30, 32); and
(v) indicator means (26), located proximate said partition and responsive to movement of said partition, for indicating leakage.
2. The case of claim 1 , wherein said partition (25) includes a flexible membrane.
3. The case of claim 1 , wherein said detector (20) has a transparent portion so that said partition movement is visible to a user.
4. The case of claim 1 , wherein said second port means (23) has a self-closing, unidirectional valve (24) which mediates between said second sub-chamber (32) and the environment in response to pressure directed into said second sub-chamber (32).
5. The case of claim 1 further comprising injection means (40) for injecting air from the environment through said second port means (23) and into said second sub-chamber (32) to increase the air pressure therein.
6. The case of claim 2 further comprising injection means (40) for injecting air from the environment through said second port means (23) and into said second sub-chamber (32) to increase the air pressure therein.
7. The case of claim 3 further comprising injection means (40) for injecting air from the environment through said second port means (23) and into said second sub-chamber (32) to increase the air pressure therein.
8. The case of claim 4 further comprising injection means (40) for injecting air from the environment through said second port means (23) and said valve (24) into said second sub-chamber (32) to increase the air pressure therein.
9. The case of claim 1 , wherein said detector (20) further comprises a plug (50) insertable into and securable to said second port means (23) which, when secured, creates a seal between the environment and said second sub-chamber (32).
10. The case of claim 2 , wherein said detector (20) further comprises a plug (50) insertable into and securable to said second port means (23) which, when secured, creates a seal between the environment and said second sub-chamber (32).
11. The case of claim 3 , wherein said detector (20) further comprises a plug (50) insertable into and securable to said second port means (23) which, when secured, creates a seal between the environment and said second sub-chamber (32).
12. The case of claim 4 , wherein said detector (20) further comprises a plug (50) insertable into and securable to said second port means (23) which, when secured, creates a seal between the environment and said second sub-chamber (32).
13. The case of claim 9 , wherein said plug (50) is configured to open said valve (24) to release air from said second sub-chamber (32) when said plug (50) is secured to said second port means (23).
14. The case of claim 10 , wherein said plug (50) is configured to open said valve (24) to release air from said second sub-chamber (32) when said plug (50) is secured to said second port means (23).
15. The case of claim 11 , wherein said plug (50) is configured to open said valve (24) to release air from said second sub-chamber (32) when said plug (50) is secured to said second port means (23).
16. The case of claim 12 , wherein said plug (50) is configured to open said valve (24) to release air from said second sub-chamber (32) when said plug (50) is secured to said second port means (23).
17. The case of claim 16 , wherein said plug (50) has first sealing means (42) and second sealing means (43) which, when secured to said second port means (23), (i) bracket said first port means (31) so as to prevent leakage between said first sub-chamber (30) and the environment, and (ii) seal said second sub-chamber (32) from said first sub-chamber (30) and the environment.
18. A leakage detector (20) for a sealed housing (10) with an outer wall, comprising:
(i) a chamber with first and second sub-chambers (30, 32);
(ii) first port means (31) by which said first sub-chamber (30) communicates with the environment;
(iii) second port means (23) by which said second sub-chamber (32) communicates with the environment;
(iv) a partition (25) separating said first sub-chamber (30) from said second sub-chamber (32) which moves in response to the difference in the respective air pressures of said first and second sub-chamber (30, 32); and
(v) indicator means (26), located proximate said partition (125) and responsive to movement of said partition (25), for indicating leakage.
19. The detector of claim 18 , wherein said partition (125) includes a flexible membrane and the detector (20) has a portion proximate said membrane to permit a user to view movement of said membrane.
20. The detector of claim 18 , further comprising a transparent tube (126) which connects said first sub-chamber (30) from said second sub-chamber (32) and said partition includes an oil drop (125) disposed within said tube.
21. A method of detecting leakage in a case, comprising the steps of:
(a) creating a first sub-chamber (32) of pressurized air in communication with the interior of the case;
(b) creating a second sub-chamber of air at atmospheric pressure (30);
(c) wherein a transparent tube (126) connects said first sub-chamber (32) and said second sub-chamber (30) and an oil drop (125) is disposed within said tube (126), wherein said oil drop (125) moves in response to the relative differences in air pressures of said first and second sub-chambers (32, 30).
22. A method of detecting leakage in a case, comprising the steps of:
(a) creating a first sub-chamber (30) in communication with the environment;
(b) creating a second sub-chamber (32) of pressurized air in communication with the interior of the case and with the environment;
(c) abutting a portion of said first sub-chamber (30) with a portion of said second sub-chamber (32) where the abutment takes the form of a partition (25) which moves in response to the difference in respective air pressures of said first and second sub-chambers.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/927,094 US20020001462A1 (en) | 1997-03-18 | 2001-08-09 | Leakage detector for a sealed housing |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/819,339 US5870632A (en) | 1997-03-18 | 1997-03-18 | Leakage detector |
PCT/CA1999/000122 WO2000048041A1 (en) | 1997-03-18 | 1999-02-09 | Leakage detector for a sealed housing |
US09/927,094 US20020001462A1 (en) | 1997-03-18 | 2001-08-09 | Leakage detector for a sealed housing |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/CA1999/000122 Continuation-In-Part WO2000048041A1 (en) | 1997-03-18 | 1999-02-09 | Leakage detector for a sealed housing |
Publications (1)
Publication Number | Publication Date |
---|---|
US20020001462A1 true US20020001462A1 (en) | 2002-01-03 |
Family
ID=25227866
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/819,339 Expired - Fee Related US5870632A (en) | 1997-03-18 | 1997-03-18 | Leakage detector |
US09/927,094 Abandoned US20020001462A1 (en) | 1997-03-18 | 2001-08-09 | Leakage detector for a sealed housing |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/819,339 Expired - Fee Related US5870632A (en) | 1997-03-18 | 1997-03-18 | Leakage detector |
Country Status (2)
Country | Link |
---|---|
US (2) | US5870632A (en) |
WO (1) | WO2000048041A1 (en) |
Cited By (6)
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US20110174377A1 (en) * | 2010-01-20 | 2011-07-21 | Keon Jae Lee | Manufacturing method for flexible device, flexible device, solar cell, and light emitting device |
US20110187915A1 (en) * | 2008-09-08 | 2011-08-04 | Senjung Chen | Waterproof Camera Sealing Device and Sealing Method Thereof |
US20110249965A1 (en) * | 2010-04-12 | 2011-10-13 | Michael Wayne Appel | Lens Guard |
US20150283335A1 (en) * | 2014-04-07 | 2015-10-08 | Medtronic Minimed, Inc. | Waterproof indicator and method of use thereof |
US9733150B2 (en) | 2014-06-24 | 2017-08-15 | Htc Corporation | Water resistance inspection system and inspection method |
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US6572395B1 (en) * | 1999-06-30 | 2003-06-03 | Electrical Wiring Component Applications Partnership | Air expansion compensator |
US6625394B2 (en) | 2001-12-21 | 2003-09-23 | Eastman Kodak Company | Two-shot molded seal integrity indicator, underwater camera, and method |
US6636695B2 (en) | 2001-12-21 | 2003-10-21 | Eastman Kodak Company | Dual action shutter release with thumbwheel brake and methods |
US6574429B1 (en) | 2001-12-21 | 2003-06-03 | Eastman Kodak Company | Underwater camera having viewports bearing on viewfinder tunnel of frame |
US6574435B1 (en) | 2001-12-21 | 2003-06-03 | Eastman Kodak Company | Underwater camera housing having sealed pivotable shutter actuator and method |
US6618555B2 (en) | 2001-12-21 | 2003-09-09 | Eastman Kodak Company | Underwater one-time-use camera having camera frame assembly retained in front housing part at unloading |
US6636697B2 (en) | 2001-12-21 | 2003-10-21 | Eastman Kodak Company | Depressurized underwater one-time-use camera with seal integrity indicator and method |
WO2014042547A1 (en) * | 2012-09-12 | 2014-03-20 | Siemens Aktiengesellschaft | A hermetically sealed apparatus, particularly for use in a subsea environment |
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US3859845A (en) * | 1973-03-05 | 1975-01-14 | Nasa | Leak detector |
DE3110575A1 (en) * | 1981-03-18 | 1982-09-30 | Siemens AG, 1000 Berlin und 8000 München | METHOD AND DEVICE FOR TIGHTNESS TESTING OF ELECTRICAL COMPONENTS |
DE3315266C2 (en) * | 1983-04-27 | 1993-10-21 | Fuji Electric Co Ltd | Semiconductor pressure sensor |
US4763145A (en) * | 1986-03-26 | 1988-08-09 | Fuji Photo Film Co., Ltd. | Water-resistant camera with automatic internal air-pressure adjustment |
US4853722A (en) * | 1987-08-14 | 1989-08-01 | Sea Fathoms Industries | Method and apparatus for extending the depth range of underwater equipment |
DE3837624A1 (en) * | 1988-11-05 | 1990-05-10 | Afriso Euro Index Gmbh | Device for the measurement of pressure changes |
JP2962942B2 (en) * | 1992-07-31 | 1999-10-12 | キヤノン株式会社 | Electronic equipment, storage unit and abnormality detection system |
-
1997
- 1997-03-18 US US08/819,339 patent/US5870632A/en not_active Expired - Fee Related
-
1999
- 1999-02-09 WO PCT/CA1999/000122 patent/WO2000048041A1/en active Application Filing
-
2001
- 2001-08-09 US US09/927,094 patent/US20020001462A1/en not_active Abandoned
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
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US20110187915A1 (en) * | 2008-09-08 | 2011-08-04 | Senjung Chen | Waterproof Camera Sealing Device and Sealing Method Thereof |
US20110174377A1 (en) * | 2010-01-20 | 2011-07-21 | Keon Jae Lee | Manufacturing method for flexible device, flexible device, solar cell, and light emitting device |
US20110249965A1 (en) * | 2010-04-12 | 2011-10-13 | Michael Wayne Appel | Lens Guard |
US8358928B2 (en) * | 2010-04-12 | 2013-01-22 | Aadyn Technology, Llc | Lens guard |
US20150283335A1 (en) * | 2014-04-07 | 2015-10-08 | Medtronic Minimed, Inc. | Waterproof indicator and method of use thereof |
US9733150B2 (en) | 2014-06-24 | 2017-08-15 | Htc Corporation | Water resistance inspection system and inspection method |
US10672252B2 (en) | 2015-12-31 | 2020-06-02 | Delta Faucet Company | Water sensor |
US11217082B2 (en) | 2015-12-31 | 2022-01-04 | Delta Faucet Company | Water sensor |
Also Published As
Publication number | Publication date |
---|---|
US5870632A (en) | 1999-02-09 |
WO2000048041A1 (en) | 2000-08-17 |
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Legal Events
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STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |