Abstract:
A fluid safety discharge system for a relief valve having an inlet and an outlet includes a bushing frictionally engaging the relief valve outlet. The relief valve outlet is internally threaded for engaging with a threaded device, such as a discharge line. The bushing may contain a separate body and engagement region for use with hard-plumbed discharge lines. Optionally, an adapter may be used for retrofitting the bushing to an existing relief valve.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates to the safe discharge of fluids and more particularly, to a pressure relief valve having a tamperproof outlet.  
         BACKGROUND INFORMATION  
         [0002]    Common residential and commercial water heaters and boilers generally include a pressurized tank or vessel in which the heated water is stored until required for use. The temperature and pressure of the water stored within the tank will typically vary within predetermined limits when the water heater operates normally. However, when a malfunction occurs, the temperature and/or pressure of the water stored within even a common residential water heater are capable of inflicting severe damage. If the tank itself should fail, for example, due to excessive pressure in the water supply, boiling of the water, or age, high temperature water may be spread explosively from the tank over a considerable distance.  
           [0003]    To avoid these catastrophic results, common residential and commercial water heaters and boilers always include a relief valve that releases water/steam when temperature and/or pressure of the water within the tank exceeds a predetermined value. The discharge side of the relief valve is generally threaded, allowing for the connection of a discharge pipe that releases the heated water into a reservoir or along the floor where there is less danger of injury to individuals.  
           [0004]    While known relief valves are a significant and well-known safety feature of common water heaters and boilers, they often develop slow leaks. Many systems, however, do not utilize reservoirs or drains. As a result, homeowners often permanently plug the outlet of the relief valve to avoid the water from dripping onto the floor. The act of permanently plugging the relief valve is commonplace and has resulted in many injuries and deaths. This is due to the inability of the plugged relief valve to perform as it was intended.  
           [0005]    Furthermore when left exposed, the outlet on the relief valve may become blocked by freezing, rust, improper sizing, and foreign materials such as dirt, leaves, etc. The situations described are also applicable to other relief valves such as those found on any pressurize (CO 2 , NO 2 , O 2 , etc.) tanks, boilers, or water/steam vessels.  
           [0006]    For the above reasons, it would be desirable to provide a fluid discharge system that would allow reduce the possibility of blockage of the relief valve, while still allowing the relief valve to properly function when the condition in the tank or boiler becomes unsafe. Ideally, such a system should be low in cost and easily installable.  
         SUMMARY  
         [0007]    The present invention is a fluid safety discharge system. The system comprises a relief valve and a bushing. The bushing has a body and internal threads. The bushing engages frictionally with a discharge outlet of the relief valve and allows the bushing to disengage from the relief valve at a predetermined pressure, thereby allowing the relief valve to perform as intended even if the bushing or connected piping is plugged. The system may optionally be coupled to a discharge line.  
           [0008]    The bushing may optionally include an adapter portion for use with an existing relief valve. Additionally, the bushing may include a tamper-proof device that further prevents a homeowner from removing it from the relief valve. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    These and other features and advantages of the present invention will be better understood by reading the following detailed description, taken together with the drawings wherein:  
         [0010]    [0010]FIG. 1 is a perspective view of one embodiment of the fluid safety discharge system of the present invention;  
         [0011]    [0011]FIG. 2 is a side view of one embodiment of a bushing of the present invention;  
         [0012]    [0012]FIG. 3 is an end view of one embodiment of the present invention;  
         [0013]    [0013]FIG. 4A is a side view of one embodiment of the body of a bushing;  
         [0014]    [0014]FIG. 4B is an end view of another embodiment of the body of a bushing;  
         [0015]    [0015]FIG. 5 is a cross sectional view of one embodiment of the present invention;  
         [0016]    [0016]FIG. 6 is a side view of another embodiment of the present invention;  
         [0017]    [0017]FIG. 7 is an exploded view of one embodiment of the present invention with an existing relief valve;  
         [0018]    [0018]FIG. 8 is another embodiment of the present invention;  
         [0019]    [0019]FIG. 9 is a plan view of one embodiment of a bushing engagement portion of the present invention having a smooth outer surface;  
         [0020]    [0020]FIG. 10 is a plan view of one embodiment of a bushing engagement portion of the present invention having a multi-sided outer surface;  
         [0021]    [0021]FIG. 11 is an exploded view of one embodiment of the present invention including a tamper-proof device; and  
         [0022]    [0022]FIG. 12 is a perspective view of one embodiment of the present invention assembled having a discharge line. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]    The fluid safety discharge system  10 , FIG. 1, according to the present invention comprises a relief valve body  11  and an internally threaded bushing  20 . The relief valve  11  may be any type of relief valve  11  designed for any type of fluid (i.e. liquid or gaseous). The relief valve  11 , as is well known in the art, has an inlet  12 , an outlet  14 , and a control mechanism represented generally at  13 . The inlet  12  is connected to the potentially hazardous source, e.g. a hot water heater (not shown). In one embodiment, the outlet  14  has walls  15  that are generally smooth.  
         [0024]    The bushing  20 , FIG. 2, has a body portion  22  and a flange portion  23  which also includes a gripping region  21 , FIG. 3, such as a several sided flange which can be gripped by a pipe wrench. In a preferred embodiment, the body  22  is slightly tapered. The body  22  is sized so that when the bushing  20  releases from the outlet  14 , the remaining area for the hazardous material (e.g. hot water or steam) to exit is equal to, or greater than, the area that is required by state or local regulation.  
         [0025]    The surface of the body  22  may be smooth, FIG. 2, or have undulating or alternating high and low protrusions  24 , FIGS. 4A and 4B. In one embodiment, the protrusions  24 ′, FIG. 4A, are annular. In another embodiment, the protrusions  24 ″, FIG. 4B, are longitudinal.  
         [0026]    The protrusions  24  are designed to facilitate a frictional fit with the walls  15  of outlet  14  of the relief valve  11 . It should be noted that the bushing  20  need not create a watertight seal. In cold climates, for example, a water tight seal may allow the liquid to back up in the relief valve  11  outlet  14  and eventually freeze, thus blocking the relief valve  11 . Therefore, a non-water tight seal may be preferable.  
         [0027]    The bushing  20  is typically made of a material having sufficient rigidity to allow the bushing to be secured to the outlet  14  of the relief valve  11 , yet flexible enough allow the bushing  20  to disengage the outlet  14  when sufficient pressure has built up. In a preferred embodiment, the material is a synthetic material, such as plastic, but may also be a metal or composite. The rigidity and flexibility of the material will depend upon the application, but is within the knowledge of one of ordinary skill in the art.  
         [0028]    Additionally, the body  22  includes internal threads  25 , FIG. 5, typically IPS pipe threads, for engaging with a discharge pipe or other similar attachment fittings.  
         [0029]    In a preferred embodiment, the bushing  20 , FIG. 6, is a two-part device that includes a body portion  22  and separate engagement portion  30 . This embodiment is particularly useful when the bushing  20  is coupled to a drain line  32  that is hard plumbed and will not easily disengage from the relief valve  11  such as when discharge pipe  32  passes through or is attached or bracketed to a wall or the like. The drain line  32  would be threaded into the engagement portion  30 .  
         [0030]    In the event that the drain line  32  becomes plugged, the body portion  22  will release from the outlet  14  and the engagement portion  30 , thus allowing the relief valve  11  to function properly. Without a separate body portion  22  and engagement portion  30 , a hard plumbed drain line  32  could prevent the bushing  20  from disengaging. In this embodiment, the cross-sectional area  33  formed by one end of body portion  22  would be sized to provide enough area to meet applicable state or local codes.  
         [0031]    In yet another embodiment, a retrofit system  40 , FIG. 7, may include a bushing  20 , which may be any one of the above-described embodiments, and a bushing adapter  42 . The adapter  42  is adapted to be threaded within an existing relief valve  44  and has an engagement region  46 , typically IPS threads, that engages the outlet threads  48  of the relief valve  44 . The adapter  42  also includes a bushing engagement region  50  that receives a bushing  20  and is sized to ensure that the system  40  complies with local regulations.  
         [0032]    In a further embodiment of a retrofit system  52 , FIG. 8, there is provided a bushing  20 , which may be any one of the above-described embodiments, a bushing engagement portion  54 , and an adapter portion  56 . The adapter portion  56  is sized to fit within an existing relief valve  44  and includes an engagement region  46 , typically IPS threads, that engages the outlet threads  48  of the relief valve  44 .  
         [0033]    The bushing engagement portion  54  is sized to ensure that the system  40  complies with local regulations and is held in place by the adapter portion  56 . The bushing engagement portion  54  can have a smooth outer surface  60 , FIG. 9, to further prevent homeowners from tampering with the system  52  or a multi-sided surface  62 , FIG. 10.  
         [0034]    In a preferred embodiment, the system  52  further includes a tamper-proof element  64 , FIG. 11, including, for example, but not limited to, a crush ring/pin or a locking ring, to prevent homeowners from removing the bushing engagement portion  54  to plug the relief valve  44 .  
         [0035]    In yet another embodiment, the system  52 , FIG. 12 may further include an adapter portion  56  having one or more tabs  57 , and a bushing engagement portion  54 , FIG. 13, having one or more notches  58 . During installation, the installer rotates the bushing engagement portion  54  wherein the tabs  57  on the adapter portion  56  engage the notches  58  on the bushing engagement portion  54 , thereby allowing the bushing adapter  56  to be screwed into the existing relief valve  44 .  
         [0036]    In one embodiment, the tabs  57  are designed to bend or break at a predetermined torque, preventing the bushing from being removed from the valve. This allows the installer to torque the adapter portion  56  to the proper specification while at the same time preventing someone from removing the system  52 . In another embodiment, the tabs  57  engage the notches  58  in a ratchet motion wherein the adapter portion  56  can only be rotated in one direction. Alternatively, the tabs  57  and the notches  58  may be located on the bushing engagement portion  54  and the adapter portion  56  respectively without departing from the present invention.  
         [0037]    When an unsafe condition exists in the tank or other attached device  36 , FIG. 14, the relief valve  11  opens thus mitigating the condition. When the pressure on the outlet  14  of the relief valve  11  reaches a predetermined point, the bushing  20  disengages the outlet  14  of the relief valve  11  thereby allowing the fluid to escape. Bushing  20  will prevent the unsafe blocking of the relief valve outlet by insuring that even if the outlet is plugged or blocked, the bushing  20  will be pushed out of the valve outlet.  
         [0038]    Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims.