Abstract:
A plumbing pipe plug apparatus configured for insertion into a section of pipe and adapted to radially expand so as to engage the inner surface of the pipe and form a positive seal therewith is disclosed. The pipe plug is adapted with a conduit having a check valve that opens in response to fluid pressure to enable the injection into the plumbing system of a pressurized fluid, such as water, to pressurize the system downstream of the plug to allow for leak inspection and pressure testing.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
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   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
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   COPYRIGHT NOTICE 
   A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyrights rights whatsoever. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a pipe leak testing apparatus, and more particularly to a plumbing pipe plug for testing plumbing systems for fluid integrity. 
   2. Description of Related Art 
   Plumbing and piping systems are typically constructed by connecting sections of pipe with fittings, valves, and other accessories. It is customary for plumbing systems to be pressure tested for leaks prior to entering service. Such tests require that the plumbing system, or a section thereof, be pressurized and inspected for leaks. In addition, it is often necessary to isolate a section of pipe for various reasons. For example, maintenance matters and safety considerations often require that a particular section of pipe connected to a system be isolated from the rest of the system while work is being performed. 
   Accordingly, there exists a need for an easy to install pipe test plug for isolation of piping systems during testing, repair and maintenance, for bypassing of damaged lines, and for isolation of piping systems during construction. More particularly, there exists a need for a pipe plug apparatus configured for insertion into a section of pipe and adapted to radially expand so as to engage the inner surface of the pipe and form a positive seal therewith. There further exists a need for such an apparatus wherein a pressurized fluid, such as water, may be injected into the pipe system to pressurize the system to allow for leak inspection and pressure testing. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention addresses the needs in the art by providing a plumbing pipe plug apparatus configured for insertion into a section of pipe and adapted to radially expand so as to engage the inner surface of the pipe and form a positive seal therewith. The plumbing pipe plug is further adapted to enable the injection into the plumbing system of a pressurized fluid, such as water, to pressurize the system downstream of the plug to allow for leak inspection and pressure testing. 
   Accordingly, it is an object of the present invention to provide a plumbing leak detection apparatus. 
   Another object of the present invention is to provide a plumbing pipe plug apparatus configured for insertion into a section of pipe and adapted for radial expansion to form a seal. 
   Still another object of the present invention is to provide a plumbing pipe plug apparatus adapted for pressurizing a section of pipe by forming a positive seal while providing a conduit for a pressurized fluid, such as water, to enter the pipe. 
   In accordance with these and other objects, which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  depicts a side view of a plumbing pipe plug apparatus according to the present invention; 
       FIGS. 2 and 3  are perspective views thereof; 
       FIGS. 4–6  are perspective sectional views thereof; 
       FIG. 7  is a sectional view depicting fluid flow and a descriptive flow chart; and 
       FIGS. 8–10  illustrate the plumbing pipe plug apparatus inserted within a section of pipe. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   With reference now to the drawings  FIGS. 1–10  depict a plumbing pipe plug apparatus, generally referenced as  10 , according to the present invention. Plumbing pipe plug apparatus  10  is generally cylindrically shaped for insertion within a section of pipe or tubing. Pipe plug  10  relies primarily on pneumatically actuated radial expansion to form a seal with the inner surface of a pipe or tube. More particularly, pipe plug  10  includes a cylindrical conduit  12  axially disposed within a generally cylindrical, pneumatically expandable body  14  configured for manual insertion in, and sealing engagement with a section of pipe. Referring to  FIG. 1 , pipe plug  10  has a pneumatically expandable body  14  in the form of a pneumatic expandable bladder that has a diameter and length suited to the general diameter of the pipe or tubing in which it is installed for operation. Expandable body  14  includes an inlet port  16 , that preferably comprises a schrader valve to facilitate connection to a hose from a compressed air source for filling expandable body  14  with air so as to effect radial expansion thereof. Accordingly, inlet port  16  functions as a connection port for connection of a hose for filling expandable body  14  with a fluid, such as compressed air. The selective introduction of compressed air via inlet port  16  functions to cause radial expansion of body  14  until the peripheral edge of body  14  engages the inner wall of the conduit and forms a positive seal. 
   Pipe plug apparatus  10  further includes a rigid cylindrical conduit  12 , axially disposed relative to body  14 . Rigid cylindrical conduit  12  includes an inlet  20  and an outlet  22 . Inlet  20  is preferably threaded and outlet  22  may be threaded as best depicted in  FIG. 5 . Inlet  20  provides a connection port for connection of a hose  23  in fluid communication with a pressurized fluid source, such as a source of pressurized water, for pressurizing the pipe downstream of the plug. More particularly, once the apparatus is inserted into a vertical section of pipe and a seal is formed by radial expansion of body  14 , water may be injected above the apparatus thereby pressurizing the pipe to allow for leak testing. 
   Conduit  12  further includes a spring biased valve assembly, generally referenced as  30 , disposed therein. Valve assembly  30  functions as a back flow prevention device or check valve to allow water under sufficient pressure to flow into the pipe downstream of the plug via conduit inlet  20  and outlet  22 , while preventing backflow. More particularly, valve assembly  30  includes first and second mounting plates, referenced as  32  and  34  respectively, and an elongate rod  36  received within axial apertures on the mounting plates so as to be axially disposed in slidable engagement with mounting plates  32  and  34 . Each mounting plate  32  and  34  defines an axial aperture for receiving rod  36  and a plurality of radially spaced apertures  38  to allow for fluid flow past each plate. Rod  36  further includes a valve body  39  sized and shaped for seated sealing engagement with conduit end  22 . As best depicted in  FIG. 5 , the valve assembly  30  is biased to a closed position by a helical spring  40  disposed in surrounding relation with rod  36  between a stop  42  connected to the rod and plate  34 . Helical spring  40  thus biases the valve assembly  30  to a closed configuration wherein valve body  39  is sealingly seated within outlet  22  thereby preventing backflow. In addition, when hose  23  is connected to inlet  20  and pressurized water flows into conduit  12 , through plate apertures  38 , the pressure acting on valve body  39  causes valve assembly  30  to open by unseating the valve body from its sealed configuration thereby allowing water to flow through the apparatus into the pipe system. When the user turns the water supply off, spring  40  causes valve body  39  to retract to the seated position thereby closing valve assembly  30  and maintaining the pressure within the downstream pipe system by preventing backflow. The valve assembly may be manually opened by the user by pushing on knob  42  on rod  36  thereby unseating valve body  39  and effectively opening the valve. 
   As best illustrated in  FIGS. 8–10 , leak testing apparatus  10  is employed by first inserting apparatus  10  into a section of pipe and inflating expandable body  14  by connection of a compressed air hose to schrader valve  16  thereby causing body  14  to radially expand until sealing engagement is achieved with the inner surface of the surrounding pipe. A water hose  23  is then threadably connected to conduit end  20  and water flow is initiated. Water flows through conduit  12  and plate apertures  38  until reaching valve body  39  wherein the water pressure acts on the valve assembly by overcoming the biasing force thereby forcing valve body  39  from its seated configuration to a longitudinally spaced open configuration whereby water is allowed to flow out of outlet  22  into the pipe system. Once sufficient water is introduced though apparatus  10  into the pipe system to adequately pressurize the system water flow is terminated and spring  40  retracts valve body  39  to the seated position thereby closing the valve and maintaining pressure on the pipe system downstream of apparatus  10 . After leak testing is completed water may be drained from the pipe system by pushing knob  42  projecting from inlet end  20  so as to unseat valve body  39  thereby opening the valve and allowing water to flow from the pipe system in reverse flow via outlet  22  conduit  12  and inlet  20 . Finally, the user bleeds air from expandable body  14  using Schrader valve  16  thereby contracting body  14  such that the apparatus may be removed from the pipe section. 
   The instant invention has been shown and described herein in what is considered to be the most practical and preferred embodiment. It is recognized, however, that departures may be made therefrom within the scope of the invention and that obvious modifications will occur to a person skilled in the art.