Abstract:
A reusable pipe fitting plug for temporarily sealing the open hub on a non-threaded female pipe fitting. The pipe fitting plug has a retainer with piercing edges, expandable pins or grit type particles designed to engage the inner portion of a pipe fitting hub in order to anchor the pipe fitting plug. The pipe fitting plug further has an expandable rubber seal or expandable rubber bladder designed to provide a watertight seal.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Application claims the priority of Provisional Application Ser. No. 60/433,334, filed Dec. 13, 2002. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to reusable pipe fitting plugs for temporarily sealing an open hub of a non-threaded female pipe fitting. 
     2. Art Relating to the Invention 
     Reusable pipe fitting plugs provide an inexpensive means to control the unwanted release of fluids or air from an open pipe connection. Reusable pipe fitting plugs can also be used to isolate various sections of a pipe system during construction or maintenance. 
     Conventional reusable pipe fitting plugs are designed with an expandable rubber sealing means that is capable of forming a watertight seal between the pipe fitting plug and the inner surface of the pipe fitting hub. 
     In a typical design, the pipe fitting plug is shaped as a cylinder with a diameter of slightly less than the diameter of the pipe fitting hub that is desired to be plugged. The pipe fitting plug therefore covers the majority of the diameter of the inside of the pipe fitting hub. The expandable rubber sealing means is provided along the circumference of the pipe fitting plug and is capable of filling the gap between the outside of the pipe fitting plug and the inside of the pipe fitting hub. Fluid flow is restricted upon the plugging of the gap with the rubber sealing means. 
     Conventional pipe fitting plugs have a rubber sealing element located within a recess of the cylinder. A tightening means is designed to exert a force through the body of the pipe fitting plug so as to decrease the recess and expand the rubber sealing element. The rubber sealing element expands under the pressure exerted by the tightening means to form a watertight seal between the pipe fitting plug and the pipe fitting hub. 
     One of the drawbacks of conventional pipe fitting plugs is that they can only withstand a limited fluid pressure. When the fluid pressure against the pipe fitting plug passes a threshold value, the rubber sealing element can no longer hold the pipe fitting plug in place and the pipe fitting plug is forced out of the pipe fitting hub. This is known as plug blow out, and results in uncontrolled flooding and damage. 
     Further, debris, dirt and solvent may be deposited within the inner surface of the pipe fitting hub causing slippage between the rubber sealing element and the pipe fitting hub resulting in further undesired consequences. 
     It is therefore desirable to obtain a reusable pipe fitting plug that is capable of withstanding increased fluid pressures and soiled surfaces without becoming disengaged from the pipe fitting hub and causing flooding. 
     SUMMARY OF THE INVENTION 
     The present invention provides a reusable pipe fitting plug for temporarily sealing the open fitting connections of a plumbing system during construction or maintenance which can withstand increased fluid pressure and avoid plug blow out. 
     The present invention provides maximum seal and hold out strength by the use of a pipe fitting plug having a dedicated seal and a dedicated retaining means. 
     The seal is a conventional, expandable rubber ring or inflatable bladder which provides a watertight seal between the pipe fitting plug and the inner wall of the pipe fitting hub. 
     The retaining means is also expandable and provides a means to anchor the pipe fitting plug into the pipe fitting hub. The retaining means enables the pipe fitting plug to withstand increased fluid pressure without failure. The retaining means further prevents slippage caused by debris, dirt and solvent buildup on the inside of the pipe fitting hub. 
     Broadly, the present invention is a pipe fitting plug comprising:
         a body which is watertight;   an expandable sealing means surrounding said body for forming a watertight seal between said body and an interior surface of a pipe fitting hub;   an expandable retaining means for engaging said interior surface of said pipe fitting hub and retaining said plug in said pipe fitting hub; and   one or more adjusting means for causing said sealing means and said retaining means to engage and disengage said interior surface of said pipe fitting hub.       

     Preferably, the sealing means is an expandable rubber ring which expands to form a watertight seal between the body and the interior surface of the pipe fitting hub. The sealing means can alternatively be in the form of an expandable rubber bladder that inflates to form a watertight seal. The sealing means forms a watertight seal with the pipe fitting hub to prevent fluid from moving through or around the plug because the body itself is solid, i.e., watertight/fluidtight and the seal is watertight/fluidtight thereby blocking the whole interior area of the pipe fitting hub. 
     Preferably, the retaining means has a one or more piercing edges or projecting teeth which are movable to engage the interior surface of the pipe fitting and retain the plug in the pipe fitting hub. Alternatively, the retaining means can have one or more expandable pins which are movable to engage the interior surface of the pipe fitting hub and retain the plug in the pipe fitting hub. The retaining means can further have a plurality of grit type particles which serve to retain the plug in the pipe fitting hub. The retaining means provides the increased strength to the plug to allow the plug to withstand increased fluid pressure. 
     The retaining means and the sealing means are both movable so as to engage and disengage the interior surface of the pipe fitting hub. This allows the plug to be inserted into the pipe fitting hub, to seal and be retained in the pipe fitting hub, and to be removed from the pipe fitting hub. 
     Preferably, there is a single adjusting means which operates on both the retaining means and the sealing means such that both the retaining means and the sealing means expand and retract simultaneously. However, the retaining means and the sealing means can each have their own adjusting means. 
     According to one embodiment of the present invention, the adjusting means is composed of an end piece affixed to one end of the body, a housing that slides on the other end of the body, and a controlling force means that extends from the body through the housing, preferably along the axis of the housing. The controlling force means can be a carriage bolt with a threaded fastener or the like. The threaded fastener compresses the housing and the end piece and causes the sealing means and the retaining means to expand and contract. 
     According to another embodiment of the present invention, the adjusting means is composed of an inner chamber within the body, an air valve in communication with the inner chamber and one or more air ports in communication with the sealing means and the inner chamber. The air valve increases the air pressure within the inner chamber and the sealing means through the air ports causing the sealing means and the retaining means to expand. 
     Preferably, the retaining means and the sealing means are located within a recess of the body of the pipe fitting plug. The recess is created between an end piece of the body and a housing which surrounds the body of the pipe fitting plug. The end piece is fixed to the body while the housing moves on the body of the plug. As a result, the adjusting means can cause the housing to move along the body to or from the end piece in order to expand or contract the recess. 
     In one embodiment of the present invention, the adjusting means applies a corresponding force to the retaining means and the sealing means as the recess contracts. As a result, the retaining means and the sealing means are compressed and compelled to outwardly expand. 
     In another embodiment of the present invention, the retaining means is further composed of a tapered cone surrounding the controlling force means of the adjusting means. As the housing and the end piece contract, the expandable pins slide along the outer surface of the tapered cone causing the expandable pins to outwardly expand. 
     In yet another embodiment of the present invention, the sealing means is composed of an inflatable rubber bladder. The retaining means is composed of a plurality of grit type particles. The grit type particles of the retaining means are located within a recess of the sealing means. As the air valve pressurizes the inner chamber of the body, the rubber bladder is forced to inflate and expand outward. 
     This outward expansion causes the piercing edges, the expandable pins or the grit type particles of the retaining means to engage with the inside surface of the pipe fitting hub and also causes the sealing means to conform to the inner wall of the pipe fitting hub to provide a fluidtight seal. 
     The present invention is primarily designed for use in plumbing systems constructed of non-threaded pipes and fittings such as ABS, PVC, polypropylene and the like. In addition, the present invention can be modified to plug a pipe itself, rather than a pipe fitting hub. The plug must be therefore sized accordingly in order to fit the dimensions of the pipe. 
     The present invention is also designed to fit conventional sized piping, namely 1.5, 2, 3, and 4 inch piping, however, any size of piping can be plugged by the present invention. 
     Suitably, the housing can extend in an axial direction outward from the body such that the overall shape of the plug is cylindrical and allow the plug to be inserted a depth into the pipe or pipe fitting hub and to extend a distance out from the end of the pipe or pipe fitting hub. 
     These and other aspects of the present invention may be more fully understood by reference to the following drawings and description which are intended for illustrative purposes only. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of one of the embodiments of the pipe fitting plug of the present invention; 
         FIGS. 2   a – 2   c  are an installed view of a pipe fitting plug according to one of the embodiments of the present invention; 
         FIG. 3   a  is a pre-installation view of one of the embodiments of the present invention; 
         FIG. 3   b  is an installed view of a pipe fitting plug according to one of the embodiments of the present invention; and 
         FIGS. 4   a – 4   b  illustrate a top view and a side view, respectively, of the movable piercing edges of the retaining means according to one embodiment of the present invention; 
         FIG. 5  illustrates an alternative embodiment of the present invention; 
         FIG. 6  illustrates a sectional view of an alternative embodiment of the present invention; 
         FIG. 7  illustrates a sectional view of an alternative embodiment of the present invention; and 
         FIG. 8  illustrates a top view of the grit type particles of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates a preferred embodiment of the present invention. 
     As shown in  FIG. 1 , pipe fitting plug  7  is composed of body  15 , end piece  2  and cylindrical housing  8 . End piece  2  is affixed around the outer circumference of body  15  so that the majority of body  15  can be encompassed by housing  8 . Such an arrangement enables housing  8  to horizontally slide along a surface of body  15  and abut end piece  2 . 
     Housing  8  is guided by controlling force means  11  as housing  8  moves along a surface of body  15 . Controlling force means  11  protrudes through the center of body  15 , end piece  2  and housing  8  and provides a means by which housing  8  and end piece  2  can be tightened together using hex nut  10 . Rubber washer  1  provides a leak-proof seal around the head of controlling force means  11  as controlling force means  11  passes through end piece  2 . Controlling force means  11  can be any threaded fastener or a carriage bolt as illustrated in  FIG. 1 . 
       FIG. 1  illustrates the positioning of recess  14  in which the sealing means and retaining means are preferably located. The sealing means and retaining means are preferably sized so as to be substantially the same size as recess  14 . 
     The retaining means is comprised of front and rear push rings  4   a  and  4   b , retaining ring  5  and O-ring  6 . 
     Front push ring  4   a  and rear push ring  4   b  have inner angled surfaces designed to mate with an angled surface of retaining ring  5 . These angled surfaces work in conjunction to cause retaining ring  5  to protrude towards and anchor into the inside wall of a pipe fitting hub that is desired to be plugged. 
       FIGS. 1 and 2  illustrate a preferred arrangement of retaining ring  5 , front push ring  4   a  and rear push ring  4   b . The angled surfaces of front push ring  4   a  and rear push ring  4   b  serve to wedge beneath or to pinch under retaining ring  5  in order to cause retaining ring  5  to travel away from the center axis of pipe fitting plug  7  and toward pipe fitting hub  12 , see  FIG. 2   a . However, it should be understood that any particular arrangement of front push ring  4   a , rear push ring  4   b  and retaining ring  5  can be utilized in order to achieve the object of the present invention. 
     The sealing means comprises end piece  2 , rubber sealing element  3  and ring  4   a . When end piece  2  and ring  4   a  compress element  3 , element  3  expands to provide a watertight seal between pipe fitting plug  7  and the inside of the pipe fitting hub. Preferably, sealing element  3  is composed of a rubber material capable of expansion upon the exercise of a squeezing force in the direction of the axis of the pipe fitting plug. Rubber sealing element  3  is also preferably formed of a material capable of conforming to the inner wall of a pipe fitting hub  12 . 
       FIGS. 2   a ,  2   c  and  3   a  illustrate the operation the pipe fitting plug according to a preferred embodiment of the present invention. 
     Pipe fitting plug  7  is first inserted into pipe fitting hub  12  at a point of pipe fitting hub  12  that is intended to be plugged. 
     Once the pipe fitting plug is in position, a user manually tightens hex nut  10  mounted around controlling force means  11 , while nylon washer  9  serves as a bearing surface for hex nut  10 . This tightening movement causes a force to be exerted upon housing  8 , and housing  8  correspondingly moves along body  15  toward end piece  2 . The recess  14  between housing  8  and end piece  2  therefore decreases, because end piece  2  remains in a fixed position relative to the movement of housing  8 . 
     As recess  14  contracts and decreases in width, sealing element  3 , front push ring  4   a , rear push ring  4   b , retaining ring  5  and O-ring  6  are compressed together. 
     As shown in  FIG. 2   c , the angled surfaces of front push ring  4   a  and rear push ring  4   b  wedge beneath retaining ring  5  and cause retaining ring  5  to be outwardly extend toward the inner surface of pipe fitting hub  12 . O-ring  6  is provided within retaining ring  5  in order to ensure that retaining ring  5  does not collapse as retaining ring  5  is compressed and allows for expansion of piercing edges of retaining ring  5  to retract from engagement with the inside of pipe fitting hub  12 . 
     As retaining ring  5  outwardly expands, serrated piercing edges located on the upper surface of retaining ring  5  pierce into pipe fitting hub  12 . Once the piercing edges are firmly engaged into pipe fitting hub  12 , pipe fitting plug  7  is capable of withstanding increased fluid pressures without failure.  FIGS. 4   a – 4   b  illustrate the configuration of the serrated piercing edges of the retaining means. 
     Further, sealing element  3  is also caused to expand due to the force applied from front push ring  4   a  and end piece  2 . As depicted in  FIG. 2   c , a portion of sealing element  3  protrudes and conforms to the inner surface of pipe fitting hub  12  in order to form a fluidtight seal. 
     Preferably, retaining ring  5  of the present invention is designed in a “V” shape with serrated or jagged outer edges as shown in  FIGS. 4   a  and  4   b . This “V” shape allows for a sliding along the angled edges of the front and rear push rings as the front and rear push rings are contracted. However, it should be understood that any particular shape of the retaining ring, front push ring and rear push ring can be utilized so as to achieve the object of the present invention. 
     In order to disengage pipe fitting plug  7  from pipe fitting hub  12 , nut  10  is unscrewed thereby releasing pressure from both sealing element  3  and retaining ring  5 . Sealing element  3  disengages the inside of the pipe fitting hub and returns to its original shape. Retaining ring  5  disengages the inside of the pipe fitting hub and returns to its original shape because of O-ring  6 . 
     The pipe fitting plug according to the present invention is also capable of extending to reach and plug a portion of a pipe fitting hub that could not ordinarily be reached through conventional means. Housing  8  and controlling force means  11  can be indefinitely extended in order to easily plug a section of a pipe fitting hub from a distance as shown in  FIGS. 3   a  and  3   b.    
       FIG. 5  illustrates another embodiment of the present invention wherein housing  8  forms part of ring  4   b . Extension  20  is attached to housing  8 . 
       FIG. 6  illustrates another preferred embodiment of the present invention where the retaining means contains one or more expandable pins  19  which extend perpendicular to the longitudinal axis of the pipe fitting plug. 
     As shown in  FIG. 6 , housing  8  slides along body  15  and is capable of compressing body  15  against end piece  2 . Controlling force means  11  protrudes through body  15 , end piece  2  and housing  8  and enables body  15 , end piece  2  and housing  8  to be compressed together using wing nut  10 . 
     The retaining means is composed of one or more expandable pins  19 , tapered cone  16 , clips  17  and spring  18 . Wing nut  10  and controlling force means  11  are capable of compressing housing  8  thereby pushing body  15  toward end piece  2 . As body  15  is pushed toward end piece  2 , expandable pins  19  slide along the outer surface of tapered cone  16  and thereby extend outward toward the inner wall of the pipe fitting hub. As a result, the pipe fitting plug is securely anchored into the pipe fitting hub. 
     The retaining means according to this embodiment also contains clips  17  and springs  18 . Springs  18  help to retract expanding pins  19  when the plug is not compressed. Clips  17  allow for springs  18  and expanding pins  19  to be mounted to the pipe fitting plug in a firm position. 
       FIG. 6  also illustrates the positioning of sealing means  3 . Sealing means  3  is located in a recess formed between end piece  2  and body  15 . As end piece  2  and body  15  are compressed together, the recess formed between end piece  2  and body  15  contracts, and sealing means  3  is compelled to outwardly expand. This outward expansion allows for sealing means  3  to form a fluidtight seal between the pipe fitting plug and the pipe fitting hub. Preferably, the sealing means is composed of a rubber-like material that is durable as well as expandable. 
     In order to disengage the pipe fitting plug from the inner wall of the pipe fitting hub, wing nut  10  is rotated in the opposite direction to allow for housing  8  to decompress body  15  and end piece  2 . As wing nut  10  is loosened, sealing means  3  breaks contact with the inner wall of the pipe fitting hub and expandable pins  19  withdraw from the inner surface of the pipe fitting hub. Thus, the pipe fitting plug can be removed from within the pipe fitting hub and can be reused. 
       FIG. 7  illustrates yet another preferred embodiment of the present invention where the pipe fitting plug is secured to the pipe fitting hub using a plurality of grit type particles  24  while a fluidtight seal is formed using expandable rubber bladder  20 . 
     As shown in  FIG. 7 , expandable rubber bladder  20  is located within a recess of body  15  of the pipe fitting plug. Expandable rubber bladder  20  contains raised outer seal area  21  which allows for expandable rubber bladder  20  to form a fluidtight seal between the pipe fitting plug and the pipe fitting hub. Furthermore, a plurality of grit type particles  24  attach to the inner surface of the expandable rubber bladder, within outer seal area  21 . The plurality of grit type particles  24  serve to affix the pipe fitting plug to the pipe fitting hub to provide a secure attachment. The plurality of grit type particles located between outer seal area  21  of expandable rubber bladder  20  are illustrated in  FIG. 8 . 
       FIG. 7  also illustrates the operation of the adjusting means that allows for the sealing means and the retaining means to expand and contract. 
     The adjusting means according to this embodiment is composed of air valve  23 , inner chamber  25  of body  15  and air ports  22 . Air valve  23  is in communication with inner chamber  25 , which is in turn in communication with expandable rubber bladder  20  via air ports  22 . 
     Air valve  23  is capable of increasing the air pressure within inner chamber  25 . As the pressure within inner chamber  25  increases, so does the pressure within expandable rubber bladder  20 . Thus, air valve  23  is capable of inflating and deflating expandable rubber bladder  20  through the increase or decrease of air pressure within inner chamber  25 . As expandable rubber bladder  20  inflates, a fluidtight seal is formed between the outer seal area  21  of expandable rubber bladder  20  and the pipe fitting hub. 
     As expandable rubber bladder  20  approaches the inner wall of the pipe fitting hub, plurality of grit type particles  24  impregnated within the perimeter outer seal area  21  of expandable rubber bladder  20  affix to the inner wall of the pipe fitting hub. Thus, plurality of grit type particles  24  allow for the pipe fitting plug to be retained in the pipe fitting hub. 
     As air pressure is decreased from within inner chamber  25 , expandable rubber bladder  20  deflates, outer seal area  21  and the plurality of grit type particles  24  break contact with the inner wall of the pipe fitting hub and the pipe fitting plug can be disengaged from the pipe fitting hub. The pipe fitting plug can thus be reused. 
     It will be understood that the claims are intended to cover all changes and modifications of the preferred embodiments of the invention herein chosen for the purpose of illustration which do not constitute a departure from the spirit and scope of the invention.