Abstract:
A tool and method of utilizing the tool to release pressurized gas trapped between a main valve and a safety valve of a portable liquified petroleum gas tank is disclosed. The tool includes a tank safety valve release member structured to be coupled with the outlet of the fuel tank. The tank safety valve release member is configured to be inserted into the tank outlet and move the tank safety valve to an open position so that pressurized gas can escape to atmosphere.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a tool and a method for using the tool for resetting a safety valve installed on a propane tank.  
           [0003]    2. Description of Related Art  
           [0004]    An overfill prevention device (“OPD”) is a safety valve incorporated into the filling valve of a liquefied petroleum gas, e.g. propane, tank. The OPD is designed to shut off the flow of gas to a tank after the tank has been filled to a predetermined capacity, e.g. 80% capacity. This allows the gas to expand when the tank is subjected to high temperatures, thereby minimizing the potential for an explosion. In the United States, as of Apr. 1, 2002, all propane tanks weighing between four and 40 pounds require the OPD as a safety device.  
           [0005]    [0005]FIG. 1 illustrates the valve assembly  30  of a typical propane tank that is used in a variety of home applications. As shown in FIG. 1, the valve assembly  30  includes a main valve  34  that is manually operated with a rotatable handle  36  and an OPD  32  that is disposed within outlet  33 . Without the OPD  32 , there is no device to prevent gas from flowing out of the tank when the main valve is opened. Within the OPD  32  lies a spring biased safety valve  40  that is designed to cut off the flow of gas when there is nothing exerting pressure on it, such as a connected regulator, from the outside of the tank. This prevents the leakage of gas when the main valve  34  is not fully closed and there is nothing attached to the outlet  33  of the tank.  
           [0006]    Devices, such as barbeque grills, that utilize gas from propane tanks include regulators that attach directly to the propane tanks. FIG. 2 illustrates a regulator assembly  50  that includes an attachment portion  52  that is designed to engage the valve assembly  30  of FIG. 1 and provide a seal so that gas cannot escape around the regulator when the main valve is opened. The regulator assembly  50  also includes a safety device that ensures that the proper pressure is being used. Regulator assemblies  50  used in conjunction with propane tanks in the United States now require a thermal fuse as well as a spring loaded safety shutoff device  51 . The safety shut-off  51  device typically includes a free floating ball bearing  60  and a spring  61  that biases the ball bearing  60  towards a closed position. The safety shut-off device  51  reacts to a dramatic increase in line pressure by fully biasing the ball bearing  60  to the closed position, thereby blocking flow of gas into the regulator  62 . Also, if the regulator assembly  50  is exposed to excessive heat, the thermal fuse, which is made of a plastic material, will melt and thereby block the flow of gas.  
           [0007]    Any impurities contained in the gas can create problems with the operation of the system, as any contaminants introduced by other means, such as such as dropping the regulator assembly  50  on the ground. Contaminants such as dirt or non-gaseous fuel can build up in the regulator assembly  50  and affect the proper functioning of the ball bearing  60  and spring  61 . For example, contaminant build-up may cause the ball bearing  60  to stick in the closed position regardless of whether the safety shut-off device  51  has been tripped. For example, this may happen after the regulator assembly  50  is removed from the valve assembly  30  of the propane tank and the ball bearing  60  is allowed to move into the closed position via gravity, without the influence of the spring  61 . Thus, if the ball bearing  60  is stuck in the closed position, the safety shut-off device  51  will not necessarily be fully reset upon attachment of the regulator assembly  50  to the tank valve assembly  30  because the flow of gas from the tank may not necessarily push the ball bearing  60  back to an open position.  
           [0008]    The safety features of the OPD can create problems for those using propane tanks, particularly when the regulator assembly is removed from the tank and then reinstalled. Once the cut-off valve is engaged, which occurs when the regulator assembly is removed from the valve assembly, it should reopen by re-attaching the regulator assembly. However, the reattachment of the regulator assembly may not fully open the cut-off valve if the user neglects to fully re-attach the regulator assembly. This can impede the flow of gas by as much as 80%. Further, there may be a small volume of high pressure gas that gets trapped in a cavity between the main valve and the cut-off valve that further impairs the opening of the cut-off valve by creating extra resistance.  
           [0009]    This problem has frustrated many users of gas tanks equipped with the OPD. Although there is typically some flow upon reattachment of the regulator assembly to the tank valve assembly, in many cases, the flow is not adequate to ensure the proper functioning of the device utilizing the gas.  
           [0010]    For example, insect trapping devices, such as the device disclosed in U.S. Pat. No. 6,145,243, are specifically designed to utilize propane from a typical tank at a specific pressure. A regulator is used to deliver propane to the device at a constant predetermined pressure and the device performs a combustion operation to create a CO 2  laden out flow for attracting insects. If the propane enters the regulator at a pressure below the predetermined level, the insect trapping device will not operate properly, as the out flowing CO 2  content will be too low, or the combustion operation may not even commence. Thus, if the regulator assembly of an insect trapping device is not attached to the gas tank properly, the device may not function at all. This may be interpreted by the user as a problem with the insect trapping device itself rather than a problem with the propane tank connection.  
         SUMMARY OF THE INVENTION  
         [0011]    It is an aspect of the present invention to provide a reset tool for releasing pressurized gas trapped between a main valve and a tank safety valve on an outlet of a gas fuel tank. The outlet has a threaded portion and the tool includes a tank safety valve release member having a threaded portion. The release member is configured to be inserted into the tank outlet with the threaded portion of the release member engaging the threaded portion of the tank outlet so that rotation of the release member advances the release member into the outlet and into engagement with the safety valve to move the safety valve to an open position. The release member has a structure defining at least one gas escape path to enable the pressurized gas trapped between the main valve and the safety valve to escape to atmosphere when the safety valve has been moved to its open position. The tool further includes a drive part connected to the release member for allowing a user to rotate the tool to advance the release member in the outlet.  
           [0012]    It is a further aspect of the present invention to provide a reset tool for opening a regulator safety valve on a regulator assembly of a gas utilizing device. The regulator assembly is constructed to be coupled to an outlet of a gas fuel tank to establish gas fuel delivery between the tank and the device. The regulator assembly has a collar with a threaded interior configured to be engageable with a threaded exterior of the tank outlet. The tool includes a regulator safety valve release member having a threaded exterior. The release member is configured to be inserted into the collar of the regulator assembly with the threaded exterior of the release member engaging the threaded interior of the collar so that rotation of the release member into the collar and into engagement with the safety valve to move the safety valve to an open position. The tool further includes a drive part for allowing a user to rotate the tool to advance the release member in the collar.  
           [0013]    It is a further aspect of the present invention to provide a method for releasing gas trapped between a main valve and a tank safety valve on an outlet of a gas fuel tank. The method includes inserting a tank safety valve release member into the outlet of the fuel tank, engaging the release member with the tank safety valve to move the safety valve to an open position, and allowing the pressurized gas trapped between the main valve and the safety valve to escape.  
           [0014]    It is a further aspect of the present invention to provide a method for opening a regulator safety valve on a regulator assembly of a gas utilizing device. The method includes inserting a regulator safety valve release member into the regulator assembly, engaging the release member with the regulator safety valve, and moving the regulator safety valve to an open position with the release member.  
           [0015]    These and other aspects, features, and advantages of this invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are part of this disclosure and which illustrate, by way of example, the principles of this invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    Features of the invention are shown in the drawings, which form part of this original disclosure, in which:  
         [0017]    [0017]FIG. 1 is a cross-sectional view of a gas tank valve assembly with an OPD;  
         [0018]    [0018]FIG. 2 is a cross-sectional view of a regulator assembly of a gas utilizing device;  
         [0019]    [0019]FIG. 3 is a perspective view of an OPD reset tool;  
         [0020]    [0020]FIG. 4 is a top exploded view of the gas tank valve assembly of FIG. 1, the OPD reset tool of FIG. 3, and the regulator assembly of FIG. 2;  
         [0021]    [0021]FIG. 5 is a cross-sectional view taken along line  5 - 5  of FIG. 4;  
         [0022]    [0022]FIG. 6 is a perspective view of the gas tank valve assembly, the OPD reset tool, and the regulator assembly of FIG. 4 in the fully engaged position;  
         [0023]    [0023]FIG. 7 is a top view of FIG. 6; and  
         [0024]    [0024]FIG. 8 is a cross-sectional view taken along line  8 - 8  of FIG. 7. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]    The present invention is directed to an overfill prevention device (“OPD”) reset tool  10 , illustrated in FIG. 3, that is part of an overall system that includes a gas tank valve assembly  30  and a regulator assembly  50  that is located on a gas utilizing device.  
         [0026]    A typical gas tank valve assembly  30  is illustrated in FIGS. 1, 4,  5 ,  6 ,  7 , and  8 . The valve assembly  30  includes an OPD  32  and a main valve  34 . The main valve  34  includes a rotatable handle  36  that can be grasped and rotated by an operator to either open or close the main valve  34 . FIG. 5 shows the main valve  34  in an open position and FIG. 8 shows the main valve  34  in a closed position. The OPD  32  is disposed within a tank outlet  33  and includes a spring-loaded safety valve  40  that is biased by a spring  42  to a closed position. A cavity  38  lies between the main valve  34  and safety valve  40  and receives the safety valve  40  when the safety valve  40  is in the open position. In order for gas to exit the fuel tank, the main valve  34  must be in the open position and suitable force must be applied to the safety valve  40  of the OPD  32  such that the spring  42  is compressed and the safety valve  40  is in the open position. The tank outlet  33  includes a threaded portion  43 . The threaded portion  43  includes exterior threads  44  and interior threads  46 .  
         [0027]    A typical regulator assembly  50  is illustrated in FIGS. 2, 4,  5 ,  6 ,  7 , and  8 . The regulator assembly  50  includes an attachment portion  52  that attaches directly to the gas tank valve assembly  30  and a regulator  62 . The attachment portion  52  includes a rotatable collar  54  and an engaging portion  56 . The collar  54  is provided with threads  55  to receive the matching exterior threads  44  of the tank outlet  33 . The engaging portion  56  includes a hollow shaft and a shut-off device  51  disposed within the hollow shaft  58 . The shut-off device  51  typically includes a free floating ball bearing  60  and a spring  61 . The engaging portion  56  is shaped to engage the safety valve  40  of the OPD  32  such that a mechanical seal is created between the two parts. As the collar  54  is tightened onto the valve assembly  30 , the engaging portion  56  provides the suitable force needed to move the safety valve  40  to the open position against the spring bias. When the collar  54  is fully tightened, the safety valve  40  is in the fully opened position such that the gas flow is not obstructed. As long as the ball bearing  60  in the regulator assembly  50  is able to freely move back against the bias of spring  61 , when the rotatable handle  36  of the main valve  34  is turned to the fully open position, gas will enter the regulator  62 .  
         [0028]    In proper operation, before the regulator assembly  50  is removed from the valve assembly  30 , the rotatable handle  36  of the main shut off valve  34  is turned to the fully closed position. Once the main shut off valve  34  is fully closed, the regulator assembly  50  can be removed by unscrewing the collar  54  from the valve assembly  30 . As the collar  54  is removed, the spring  42  biases the safety valve  40  of the OPD  32  towards the closed position. When the regulator assembly  50  is free from the valve assembly  30 , the safety valve  40  is in the fully closed position, thereby sealing off the cavity  38  from the outside of the tank.  
         [0029]    Depending on the exact sequencing of events, pressurized gas may accidentally get trapped between the main shut off valve  34  and the safety valve  40  of the OPD  32  in the cavity  38 . This may create problems when the regulator assembly  50  is reattached to the valve assembly  30 . Often, when the regulator assembly  50  is reattached to the valve assembly  30 , the safety valve  40  of the OPD  32  does not fully open because of the pressure being exerted on it from the gas located within the cavity  38 . Similarly, the ball bearing  60  in the regulator assembly  50  may not be in the correct position to allow for the full flow of gas into the regulator  50 . This causes the gas utilizing device to not function properly. The OPD reset tool  10  insures that both the valve assembly  30  and the regulator assembly  50  function properly once the regulator assembly  50  is attached to the valve assembly  30 .  
         [0030]    The OPD reset tool  10  includes a tank safety valve release member  12  and a regulator safety valve release member  14  and a drive part  16  disposed between the tank safety valve release member  12  and the regulator safety valve release member  14 . The tank safety valve release member  12  is shaped such that it can be inserted into a gas tank valve assembly  30 . In the preferred embodiment, once the tank safety valve release member  12  of the tool  10  is fully inserted into the gas tank valve assembly  30 , it becomes fully engaged with the valve assembly  30 , as illustrated in FIGS. 6, 7, and  8 . The tank safety valve release member  12  may be substantially smooth on the outside, or it may include a threaded portion  18 . Preferably, the tank safety valve release member  12  includes the threaded portion  18  and the threaded portion  18  is engageable with the threaded portion  43  of the tank outlet  33 . This allows for the tightening and indexing of the tool  10  such that when the tool  10  is fully tightened, it moves the safety valve  40  into the fully open position. When the safety valve  40  is in the open position, any pressurized gas located on the opposite side of the safety valve  40  will escape past the reset tool  10  and out into the atmosphere, as illustrated in FIG. 8. Thus, the reset tool  10  “resets” the valve assembly  30  such that it is ready to receive the regulator assembly  50  and function properly.  
         [0031]    A cross-section of the preferred embodiment of the reset tool  10  is illustrated in FIG. 5. The tank safety valve release member  12  of the tool  10  further includes an engaging surface  20  that is shaped such that it provides the necessary force to open the safety valve  40  and allows for gas to escape out of the valve assembly  30  to the atmosphere. As shown in the figures, the tank safety valve release member  12  of the reset tool  10  is substantially solid. Alternatively, the tank safety valve release member  12  may be substantially hollow or contain holes such that any gas that escapes out of the valve assembly  30  escapes to the atmosphere through the holes or the hollow center. Also, the tank safety valve release member may be shaped such that it includes threads that engage the exterior threads  44  of the tank outlet  33 . In the preferred embodiment, the engaging surface  20  includes at least one bevel  22  so that the reset tool  10  contacts the safety valve  40  at two opposite points  23 , rather than create a complete seal between the tool  10  and the safety valve  40 . Preferably, the engaging surface  20  includes two bevels  22 . As shown in FIG. 3, the threads  18  that are disposed on the tank safety valve release member  12  are not continuous about the circumference of the tool  10 , but instead are interrupted by at least one substantially flat portion  24 . This allows for gas to escape out of the cavity  38  in a path defined between the tank outlet  33  and the flat portions  24  and into the atmosphere.  
         [0032]    The regulator safety valve release member  14  of the reset tool  10  is shaped such that it can be inserted into the attachment portion  52  of the regulator assembly  50 . Once the regulator safety valve release member  14  of the tool  10  is fully inserted into the regulator assembly  50 , it becomes fully engaged with the regulator assembly  50 , as illustrated in FIGS. 6, 7, and  8 . The regulator safety valve release member  14  may be substantially smooth on the outside, or it may include threads  26  that match the threads  55  located within the collar  54  of the regulator assembly  50 . Preferably, the regulator safety valve release member  14  includes threads  26 .  
         [0033]    The regulator safety valve release member  14  further includes a cavity  28  that is sized and shaped to received the engaging portion  56  of the regulator assembly  50 . A protrusion  29  is disposed within the cavity  28  such that it can be inserted into the hollow shaft  58  of the engaging portion  56  of the regulator assembly  50 . The protrusion  29  extends to the shut-off device  51  when the tool  10  is fully engaged with the regulator assembly  50 . The ensures that the ball bearing  60  is free to move and will not block the flow of gas once the regulator assembly  50  is reattached to the valve assembly  30 .  
         [0034]    The drive part  16  is preferably shaped to receive a leveraging tool. For example, the drive part  16  is shaped to receive a person&#39;s hand such that a person could grasp the tool and fully engage it with the valve assembly and the regulator assembly. In the preferred embodiment, illustrated in FIG. 3, the drive part  16  is substantially hexangonal in shape. This way, a wrench or the like, can be used to properly tighten the reset tool  10  with respect to the valve assembly  30  and/or the regulator assembly  50 .  
         [0035]    The reset tool  10  may be manufactured from any suitable material that will allow the proper tolerances and stiffness to ensure that the tool  10  functions properly. Preferably, the tool  10  is manufactured from metal or plastic. More preferably, the tool  10  is injection molded from a plastic with suitable hardness so as not to distort when the tool  10  is fully tightened and engaged with the valve assembly  30  or the regulator assembly  50 .  
         [0036]    In operation, before the regulator assembly  50  is attached to the valve assembly  30 , the tank safety valve release member  12  of the reset tool  10  is inserted into the valve assembly  30  and fully tightened. In the preferred embodiment, the tank safety valve release member  12  of the reset tool  10  includes threads  18  and is inserted into the valve assembly  30  and rotated in the counter-clockwise direction until the tool  10  cannot rotate any further. This ensures that the safety valve  40  is fully opened to allow for any gas located in the cavity  38  to escape to the atmosphere.  
         [0037]    The hollow shaft  58  of the regulator assembly  50  is then aligned with the protrusion  29  of the regulator safety valve release member  14  of the reset tool  10 . While holding the rest tool  10  in place, the collar  54  of the regulator assembly  50  is attached to the regulator safety valve release member  14  of the reset tool  10  and fully tightened. In the preferred embodiment, the regulator safety valve release member  14  of the reset tool  10  includes threads  26  and the collar  54  is attached to the regulator safety valve release member  14  and rotated in the clockwise direction until the collar  54  cannot be tightened any further. This ensures that the ball bearing  60  is repositioned so as to allow the flow of gas into the regulator  62  once the regulator assembly  50  is reattached to the valve assembly  30 .  
         [0038]    In the preferred embodiment, while holding the reset tool  10  in place, the collar  54  can then be rotated in the counterclockwise direction so as to loosen and become detached from the reset tool  10 . The rest tool  10  can then be rotated in the clockwise direction and removed from the valve assembly  30 . The OPD  32  is now reset and the regulator assembly  50  is ready to be attached to the valve assembly  30  of the gas tank.  
         [0039]    Alternatively, the tank safety valve release member  12  of the reset tool  10  is inserted into the valve assembly  30  and fully tightened. This ensures that the safety valve  40  is fully opened to allow for any gas located in the cavity  38  to escape to the atmosphere. The reset tool  10  is then loosened from the valve assembly  30  and removed.  
         [0040]    The regulator safety valve release member  14  of the reset tool  10  can then be inserted into the collar  54  of the regulator assembly  50 , by aligning the protrusion  29  of the reset tool  10  with the hollow shaft  58  of the regulator assembly  50 , and fully tightened. This ensures that the ball bearing  60  is repositioned so as to allow the flow of gas into the regulator  62  once the regulator assembly  50  is reattached to the valve assembly  30 . The reset tool  10  is then loosed from the regulator assembly  50  and removed.  
         [0041]    The regulator assembly  50  of the gas utilizing device is now ready to be attached to the tank valve assembly  30 . For example, an insect trapping device as described in co-owned and co-pending U.S. patent application Ser. No. 10/264,260, herein incorporated by reference in its entirety, or as described in co-owned U.S. Pat. No. 6,145,243, herein incorporated by reference in its entirety, is now ready to be attached to a propane tank. Upon attachment, the insect trapping device will now receive the proper flow of gas and will provide the proper combustion to create the proper CO 2  laden out flow for attracting insects.  
         [0042]    While preferred embodiments of the invention have been shown and described, it is evident that variations and modifications are possible that are within the spirit and scope of the preferred embodiments described herein.  
         [0043]    It is understood that any references to direction are in conformance with the current standard fittings used in such equipment and are not intended to characterize the devices as being used in any particular orientation, or as otherwise limiting.