Inflatable Elastomeric Plug For A Dual Containment Piping System

Abstract

An inflatable annular plug for use in creating a seal between an outer conduit and an inner conduit in a dual containment piping system comprises an annular structure for fitting into the piping system. A first connector is bonded to the plug for enabling the plug to be inflated by an external fluid source. A second connector extends through the plug in an axial direction for enabling fluid to flow through the plug and is bonded to the plug at both entrance and exit points. An outer surface of the plug is formed with a plurality of circumferential ribs and lands to form a plurality of axially spaced seals between the outer conduit and the plug. The plug is used in conjunction with a second plug to form a sealed test space between plugs.

1 . An isolation system for isolating a test space in a dual containment piping system having an inner conduit and an outer conduit in spaced apart relationship, the isolation system comprising: 
 a pair of annular inflatable plugs, each of the plugs having at least one pipe passing axially therethrough and at least one pipe passing thereinto, each of the pair of plugs being sized to slide into the piping system with the inner conduit fitting into a central opening in the plugs and the plugs being spaced apart to define a test space therebetween;    connector means coupled to the at least one pipe passing thereinto for enabling a flow of fluid into the plugs to inflate the plugs and form a seal at the interface of the plug with both the outer conduit and the inner conduit;    connector means coupled to the at least one pipe passing axially through the plugs for enabling a flow of fluid into the test space between the plugs for establishing a predetermined pressure therein; and    pressure sensing means for monitor the pressure in the test space to detect a pressure drop therein.    
   
   
       2 . The isolation system of  claim 1  and including a second pipe passing axially through the plugs for enabling continuous sensing of pressure in the test space.  
   
   
       3 . The isolation system of  claim 1  wherein the plugs comprise nylon reinforced SBR.  
   
   
       4 . The isolation system of  claim 3  wherein the plugs having a wall thickness of between about 0.5 inch and 1.5 inch.  
   
   
       5 . The isolation system of  claim 4  wherein the plugs have a corrugated outer circumference defined by a plurality of alternating annular lands and ribs.  
   
   
       6 . The isolation system of  claim 5  wherein the test space is pressurized to a pressure of between about 10 and 15 PSI.  
   
   
       7 . The isolation system of  claim 5  wherein the plugs are inflated to a pressure of between about 35 and 80 PSI.  
   
   
       8 . An inflatable annular plug for use in creating a seal between an outer conduit and an inner conduit in a dual containment piping system, the plug comprising: 
 an annular structure having a length at least as large as a diameter of the plug in an inflated condition;    a first connector bonded to the plug for enabling the plug to be inflated by an external fluid source;    a second connector extending through the plug in an axial direction for enabling fluid to flow through the plug, the second connector being bonded to the plug at entrance and exit points thereof; and    an outer surface of the plug being formed with a plurality of circumferential ribs and lands to form a plurality of axially spaced seals between the outer conduit and the plug.    
   
   
       9 . The inflatable annular plug of  claim 8  and including a third connector extending through the plug in an axial direction for enabling monitoring of pressure on one end of the plug from an opposite end thereof.  
   
   
       10 . The inflatable annular plug of  claim 8  wherein the plug is formed of a fiber reinforced expandable SBR material.  
   
   
       11 . The inflatable annular plug of  claim 10  wherein the wall thickness of the plug is between about 0.5 and 1.5 inch.