Leakage detector for a sealed housing

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.

What is claimed is  
     
         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.