Smoke and clean air generating machine for detecting the presence and location of leaks in a fluid system

Abstract

A smoke and clean air generating machine for detecting the presence and location of leaks in a fluid system (e.g. the evaporative or brake system of a motor vehicle). A source of gas (e.g. air or nitrogen) under pressure is delivered to a smoke generating apparatus or to a flow meter by way of a multi-position selector valve. With the selector valve in a first position, gas is delivered to the system under test via the flowmeter to detect the presence of a leak in need of repair depending upon the reading of the flow meter. With the selector valve in a second position, gas is delivered to the smoke generating apparatus so that smoke can be supplied to the system under test to locate the leak. With the selector valve in a third position between the first and second positions, pressure is bled from the machine to disable the smoke generating apparatus and thereby terminate the production of smoke.

1 - 18 . (canceled)  
   
   
       19 . A method for testing a closed fluid system for an unacceptable leak and for identifying the location of the unacceptable leak in the fluid system under test provided that an unacceptable leak is detected, said method comprising the steps of: 
 connecting a source of gas under pressure to a multi-position selector valve;    connecting a gas flow meter in a leak test line running between the fluid system under test and the selector valve;    connecting a smoke generator in a leak locator line running between the fluid system under test and the selector valve;    placing the multi-position selector valve in a first position for causing gas under pressure to flow from the source thereof through the leak test line to the fluid system under test by way of the gas flow meter;    monitoring the flow of gas under pressure in the leak test line to determine if an unacceptable leak is present in the fluid system under test depending upon a reading of the gas flow meter;    placing the multi-position selector valve in a second position if it is determined that the fluid system under test has an unacceptable leak for causing gas under pressure to flow from the source thereof through the leak locator line for blowing smoke produced by the smoke generator to the fluid system under test; and    observing the location in the fluid system under test from which the smoke being blown by the gas under pressure escapes for identifying the corresponding location of the unacceptable leak.    
   
   
       20 . The method recited in  claim 19 , including the additional step of connecting a unidirectional check valve in the leak test line between the gas flow meter and the fluid system under test to prevent the flow of smoke through the leak test line from the fluid system under test to the gas flow meter.  
   
   
       21 . The method recited in  claim 19 , wherein the gas under pressure is a non-flammable gas.  
   
   
       22 . The method recited in  claim 21 , where the non-flammable gas under pressure is nitrogen.  
   
   
       23 . The method recited in  claim 21 , wherein the non-flammable gas under pressure is carbon dioxide.  
   
   
       24 . The method recited in  claim 19 , wherein the gas under pressure is air.  
   
   
       25 . The method recited in  claim 19 , wherein the step of monitoring the flow of gas under pressure to determine if a leak is present includes the additional step of comparing the reading of the gas flow meter when the leak test line is connected to the fluid system under test with the reading of the gas flow meter when the leak test line is connected to a closed fluid system having no leak or a leak of acceptable size.  
   
   
       26 . The method recited in  claim 25 , wherein the gas flow meter has a moving indicator ball.  
   
   
       27 . The method recited in  claim 26 , wherein the step of monitoring the flow of gas under pressure to determine if a leak is present includes the additional steps of visually reading the position of the moving indicator ball of the gas flow meter when the leak test line is connected to the fluid system under test and then comparing the visual position with the reading of the moving indicator ball of the gas flow meter when the leak test line is connected to the closed fluid system having no leak or a leak of acceptable size.  
   
   
       28 . The method recited in  claim 19 , wherein the closed fluid system under test is the fuel vapor recovery system of a motor vehicle.  
   
   
       29 . The method recited in  claim 19 , including the additional step of the gas under pressure from the source thereof blowing a supply of oil carried by the smoke generator against a heated heating element of the smoke generator for producing the smoke to be blown by the gas under pressure flowing through the leak locator line to the system under test when the selector valve has been placed in the second position.  
   
   
       30 . Apparatus for testing a closed fluid system for an unacceptable leak and for identifying the location of the unacceptable leak in the fluid system under test provided that an unacceptable leak is detected, said apparatus comprising: 
 a multi-position selector valve;    a source of gas under pressure connected to said multi-position selector valve;    a first gas line running between the fluid system under test and said selector valve;    a gas flow meter connected in said first gas line;    a second gas line running between the fluid system under test and said selector valve; and    a smoke generator connected in said second gas line,    said multi-position selector valve being placed in a first position to cause gas under pressure to flow from the source thereof through said first gas line to the fluid system under test by way of said gas flow meter, a reading of the gas flow meter providing an indication of an unacceptable leak in the fluid system under test,    said multi-position selector valve being placed in a second position if it is indicated that the fluid system under test has an unacceptable leak to cause gas under pressure to flow from the source thereof through said second gas line to the fluid system under test by way of said smoke generator for blowing smoke generated by said smoke generator to the fluid system under test, the location in the fluid system under test from which the blown smoke escapes identifying the location of the unacceptable leak therein.    
   
   
       31 . The apparatus recited in  claim 30 , further comprising a unidirectional check valve located in said first gas line between said gas flow meter and the fluid system under test to prevent the flow of smoke through the first gas line from said system under test to said gas flow meter.  
   
   
       32 . The apparatus recited in  claim 30 , wherein said gas under pressure is a non-flammable gas.  
   
   
       33 . The apparatus recited in  claim 32 , wherein said non-flammable gas under pressure is nitrogen.  
   
   
       34 . The apparatus recited in  claim 32 , wherein said non-flammable gas under pressure is carbon dioxide.  
   
   
       35 . The apparatus recited in  claim 30 , wherein said gas under pressure is air.  
   
   
       36 . The apparatus recited in  claim 19 , wherein said closed system under test is the fuel vapor recovery system of a motor vehicle.  
   
   
       37 . Apparatus for testing a closed fluid system for an unacceptable leak and for identifying the location of the unacceptable leak in the fluid system under test provided that an unacceptable leak is detected, said apparatus comprising: 
 a source of gas under pressure;    a gas flow meter; and    a smoke generator;    said gas flow meter located between the source of gas under pressure and the fluid system under test during a leak testing mode of operation, whereby gas under pressure flows from said source thereof to said fluid system under test by way of said gas flow meter, a reading of said gas flow meter providing an indication of an unacceptable leak in said fluid system,    said smoke generator located between the source of gas under pressure and the fluid system under test during a leak locating mode of operation if it is indicated that the fluid system under test has an unacceptable leak, whereby gas under pressure flows from said source thereof to said fluid system by way of said smoke generator for blowing smoke generated by said smoke generator to said fluid system, the location in said fluid system from which the blown smoke escapes identifying the location of the unacceptable leak therein.    
   
   
       38 . The apparatus recited in  claim 37 , further comprising a unidirectional check valve located between the system under test and the gas flow meter to prevent the flow of smoke generated by said smoke generator from flowing from the system under test to said gas flow meter.  
   
   
       39 . The apparatus recited in  claim 37 , wherein said closed system under test is the fuel vapor recovery system of a motor vehicle.  
   
   
       40 . The apparatus recited in  claim 37 , wherein said gas flow meter has a moving indicator ball.