Patent Document

CLAIM OF PRIORITY 
   This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 60/507,265, filed on Sep. 30, 2003, which is hereby incorporated by reference. 

   BACKGROUND 
   The present invention relates generally to bleed valves used in systems comprising a pressurized fluid. More specifically, the present invention relates to methods and apparatus for automatically venting a portion of a fluid from at least a portion of a pressurized system. 
   Pressurized systems typically comprise a pressurized fluid, such as a liquid or gas, which is contained within the system at a pressure that is different from the pressure of the environment surrounding the system. A pressurized system may also comprise a valve for venting a portion of the pressurized fluid to change the pressure of the fluid or to equalize the pressure of the fluid of the system with the pressure of the surrounding environment. Such a valve for venting a portion of the pressurized fluid may be referred to herein as a “vent,” “bleed valve,” “venting valve,” or “release valve.” 
     FIG. 1  illustrates an example of a pressurized system  38  comprising a first pressurized device  40  connected to a second pressurized device  42  through a pressurized passage  48 . The pressurized passage  48  may be connected to the first pressurized device  40  through a first releasable interface  44  and to the second pressurized device  42  through a second releasable interface  46 . The first releasable interface  44  and the second releasable interface  46  may each be configured to prevent the passage of -a fluid (not shown) when closed and to allow the passage of the fluid when opened. When the first releasable interface  44  and second releasable interface  46  are both open, a pressurized fluid may flow between the first pressurized device  40  and the second pressurized device  42  through the pressurized passage  48 . For example, if the first pressurized device  40  is at a higher pressure than the second pressurized device  42  when the first releasable interface  44  and second releasable interface  46  are opened, the pressurized fluid will flow from the first pressurized device  40  to the second pressurized device  42  until the relative pressures of the first pressurized device  40  and the second pressurized device  42  are equalized or one of the pressurized interfaces  44 ,  46  are closed. 
   By way of example, the pressurized system  38  may be used to fill scuba tanks or other pressurized devices with a compressible fluid. Thus, for example, the first pressurized device  40  may comprise a pressurized air source used to fill or pressurize the second pressurized device  42  which in turn may comprise, for example, a scuba tank. As another example, the first pressurized device  40  may comprise a large scuba tank used to fill a smaller scuba tank (i.e., the second pressurized device  42 ) with compressed air. 
   An artisan will recognize that the pressurized system  38  can be adapted to accommodate a wide range of fluid pressures. For example, scuba tanks are typically rated to withstand air pressures ranging from approximately 1800 PSI (i.e., approximately 124 bar) to approximately 3000 PSI (i.e., approximately 206 bar) or higher in the United States. In other countries, scuba tanks are rated to withstand air pressures ranging from approximately 3000 PSI (i.e., approximately 206 bar) to approximately 4500 PSI (i.e., approximately 310 bar). 
   The pressurized system  38  may also comprise a vent  50  coupled to the pressurized passage  48 . The vent  50  may also be coupled to a vent controller  52  configured to manually open and close the vent  50  to alter the pressure of the fluid in at least a portion of the pressurized system  38 . For example, if the first releasable interface  44  is closed and the second releasable interface  46  is open, opening the vent  50  with the vent controller  52  will alter the pressure in the passage  48  and the second pressurized device  42 . Similarly, if both releasable interfaces  44 ,  46  are closed, opening the vent  50  will only alter the pressure of the fluid in the passage  48 . 
     FIG. 2  illustrates an adapter  54 , such as the model 910C refill adapter available from Submersible Systems, Inc. of Huntington Beach Calif. The adapter  54  comprises a screw  56  and a yoke  58  configured to attach the adapter  54  to a first pressurized device (not shown), such as a scuba tank or other pressurized container. The adapter further comprises a fitting  60  configured to provide a fluid passage from the first pressurized device to a second pressurized device (not shown). The fitting  60  includes a vent hole  62  and a bleed screw  64  configured to open and close the vent hole  62 . The bleed screw  64  comprises a threaded stem  67  and a sealing device  68 , such as an o-ring or soft seat. 
   Charging adapters or refill adapters, such as the adapter  54  shown in  FIG. 2 , typically need a vent or release valve incorporated into their design to relieve the pressure on the fittings. For example, as shown in  FIG. 3 , the adapter  54  may be threaded onto a regulator  66 , such as the “Spare Air” regulator available from Submersible Systems, Inc., located in Huntington Beach, Calif. Typically, when filling a pressurized container (not shown) configured to attach to the regulator  66 , the adapter  54  is threaded onto the regulator  66  by the action of fingertips or special tools (not shown). For example, a user can grip the fitting  60  by hand and screw it onto the regulator  66 . 
   When the fitting  60  is not under pressure, screwing it onto the regulator  66  requires overcoming only a small resistance, such as that required to compress an o-ring (not shown). However, to unscrew and remove the adapter  54  from the regulator  66  requires that the fluid pressure be discharged from the fitting  60 . Typically, removing the adapter  54  from the regulator  66  involves first turning the bleed screw  64  by hand to release the pressure on the threads of the fitting  60  and then turning the fitting  60  by hand to unscrew it from the regulator  66 . 
     FIG. 4  illustrates instructions for filling a pressurized tank, referred to as “SPARE AIR,” from a scuba tank using a refill adapter, such as the adapter  54  shown in  FIG. 2 . As the instructions indicate, the operation of filling the pressurized tank is complicated by the need to turn two different valves in a particular sequence. In fact, if the instructions are not followed, the act of refilling will not even occur. For example, in normal operations, an operator must first screw the adapter to the corresponding threaded part. This is typically a one-way check valve on the device to be filled. Then, before opening the valve that would allow the gas or fluid to travel from the storage device or fill station, the operator must first be sure to close the vent valve of the adapter to prevent the contents from leaking out the fittings instead of refilling the device. The same problem arises after the device to be recharged is full. After shutting off the main flow control valve from the storage tank or refill station, the operator must now open the vent valve by turning it in the opposite rotation used to close it. 
   Typically, even experienced operators may make a mistake and not remember to close the vent before starting to fill, or attempt to unscrew it without first relieving the pressure. This would make it very difficult or impossible to unscrew due to the increased pressure load on the threads. This sometimes leads to the operator employing a hammer or large wrench in order to break free what are thought to be slightly stuck threads. In some cases this forcing action can shorten the life-span of the parts or even result in a sudden failure of the parts involved. This can also produce a small explosion of compressed gas that can cause the adapter or pieces thereof to fly through the air, possibly resulting in injury. 
   Further, the construction of some existing types of vent valves has been prone to easily, yet accidentally, unscrewing the vent valve so much that it is completely removed from the vent hole and lost. Additionally, some existing devices are prone to wear over time and have a tendency to either develop leaks or, even worse, completely fail under pressure, which could lead to serious injury. 
   Thus, it would be advantageous to develop a technique and device for automatically venting a fluid from a pressurized system to allow an element or component of the system to be safely removed from the system. 
   SUMMARY 
   The invention provides methods and apparatus for automatically venting a portion of a fluid from at least a portion of a pressurized system. An embodiment of the invention provides an improved method for refilling pressurized containers. Another embodiment of the invention provides an adapter with an automatic bleed valve for high pressure connections in systems configured to charge or refill lines, cylinders, or other sealed systems. This invention has overcome the stated shortcomings. 
   When being screwed in place to it&#39;s corresponding part such as a check valve, the users fingers are in contact with a knurled raised ring that serves both as a gripping surface to screw the adapter into place and as the housing for an eccentric shaped surface. This exerts force and movement to a moveable pin having a conical end (preferably made of a semi-elastic material such as nylon). The pin then creates a seal with its conical end against an orifice contained in the body of the threaded port of the adapter. 
   The operator does not need to worry about the action of opening or closing the vent valve because the simple motion of rotating the knurled ring for purposes of screwing the adapter on and off will cause the cam surface (cut into a counter bored surface of the ring) to close and open the vent. In particular, rotating the ring in one direction seats the pin to seal the vent hole and turning the ring in the opposite direction will allow the pin to unseat and thus cause the valve to vent. All of this occurs without the operator&#39;s attention. Thus, using a high-pressure refilling device or an adapter between two pressurized devices is simple and safe. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings, which illustrate what are currently considered to be best modes for carrying out the invention: 
       FIG. 1  is a block diagram of a pressurized system; 
       FIG. 2  is a photograph of an adapter with a manual bleed screw; 
       FIG. 3  is a photograph of the adapter of  FIG. 2  coupled to a regulator; 
       FIG. 4  is an illustration of refill instructions employing the adapter of  FIG. 2 ; 
       FIG. 5  is a block diagram of a pressurized system with an automatic vent, according to an embodiment of the invention; 
       FIG. 6  is a schematic diagram of an adapter assembly with an automatic vent, according to an embodiment of the invention; 
       FIG. 7  is a schematic diagram illustrating the interconnection of various components of the adapter assembly shown in  FIG. 6 , according to an embodiment of the invention; 
       FIG. 8  is a detailed schematic of the adapter fitting shown in  FIG. 7 , according to an embodiment of the invention; 
       FIG. 9  is a detailed schematic of the swivel nut shown in  FIG. 7 , according to an embodiment of the invention; 
       FIG. 10  is a detailed schematic of the swivel fitting shown in  FIG. 7 , according to an embodiment of the invention; 
       FIG. 11  is a detailed schematic of the pin vent shown in  FIG. 7 , according to an embodiment of the invention; 
       FIG. 12  is a detailed schematic of the cam ring shown in  FIG. 7 , according to an embodiment of the invention; 
       FIG. 13  is a cross-sectional cut view of the swivel fitting shown in  FIG. 7  illustrating the cam ring positioned to allow fluid to escape past the pin vent, according to an embodiment of the invention; 
       FIG. 14  is a cross-sectional cut view of the swivel fitting shown in  FIG. 7  illustrating the cam ring positioned to push down on the pin vent and prevent fluid from flowing out of the vent hole, according to an embodiment of the invention; 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 5  illustrates a block diagram of a pressurized system  53  according to an embodiment of the invention. The pressurized system  53  comprises a first pressurized device  40  configured to be coupled to a second pressurized device  42  through a pressurized passage  49 . The pressurized passage  49  is configured to be coupled to the first pressurized device  40  through a first releasable interface  44  and to the second pressurized device  42  through a second interface  70 . The second interface  70  comprises an automatic bleed valve (not shown) which is configured to seal a vent hole (not shown) when the second interface  70  is attached to the second pressurized device  42  and to unseal the vent hole before the second interface  70  is detached from the second pressurized device  42 . 
   By way of example, the pressurized system  53  may be used to fill scuba tanks or other pressurized devices with a compressible fluid such as air. Thus, for example, the first pressurized device  40  may comprise a pressurized air source used to fill or pressurize the second pressurized device  42  which in turn may comprise, for example, a scuba tank. As another example, the first pressurized device  40  may comprise a large scuba tank used to fill a smaller scuba tank (i.e., the second pressurized device  42 ) with compressed air. However, an artisan will recognize from the disclosure herein that the adapter of the present invention may be used to fill scuba tanks of any size and that the relative sizes of the first pressurized device  40  and the second pressurized device  42  are not limiting. 
   In an exemplary embodiment, the second pressurized device  42  comprises a miniature scuba tank for storing approximately three cubic feet of air and having a length of approximately 13.4 inches, a diameter of approximately 2.25 inches, and a pressure rating of approximately 3000 PSI. In another exemplary embodiment, the second pressurized device  42  comprises a miniature scuba tank for storing approximately 1.7 cubic feet of air and having a length of approximately 8.75 inches, a diameter of approximately 2.25 inches, and a pressure rating of approximately 3000 PSI. An artisan will recognize from the disclosure herein that the pressurized system  53  can be adapted to accommodate a wide range of fluid volumes and pressures. 
     FIG. 6  is a schematic diagram of an adapter assembly  12  according to an embodiment of the invention. The adapter assembly  12  comprises a screw  1 , a yoke  10 , an adapter fitting  2 , a swivel fitting  3 , a swivel nut  4 , a ring vent or cam ring  5 , and a retaining ring  6 .  FIG. 7  illustrates the interconnection of various components of the adapter assembly shown in  FIG. 6 . The adapter fitting  2  and swivel fitting  3  are configured to couple together to form a fluid passage  24  having a first end  16  and a second end  18 . As shown in  FIG. 7 , the swivel fitting  3  comprises a resealable vent  14  configured to release pressure from the fluid passage  24  when unsealed. 
   The screw  1  and yoke  10  are configured to secure the adapter assembly  12  to a first pressurized device (not shown), such as a scuba tank, so that the adapter fitting  2  may interface with the first pressurized device. The swivel nut  4  is configured to slide over the swivel fitting  3  and to thread onto the adapter fitting  2  to secure the adapter fitting  2  to the swivel fitting  3  and yoke  10 . Thus, the swivel nut  4  holds the flange of the adapter fitting  2  firmly against the opening of the yoke  10  while allowing the swivel fitting  3  to rotate. A washer  7  and a seal  8 , such as an o-ring, are placed at the interface of the adapter fitting  2  and swivel fitting  3  to allow the swivel fitting  3  to rotate freely while maintaining a pressure seal for the fluid passage  24  between the adapter fitting  2  and the swivel fitting  3 . The swivel fitting  3  is configured to interface with a second pressurized device (not shown), such as a miniature scuba tank, at the second end  18  of the fluid passage  24 . 
   In operation, the adapter assembly  12  is configured to automatically seal the vent  14  when attached to the second pressurized device and to automatically unseal the vent  14  before being detached from the second pressurized device. Thus, the adapter assembly  12  can be safely used to transfer fluid in a pressurized system. For example, the adapter assembly  12  shown in  FIGS. 6 and 7  can be used to fill a small scuba tank with compressed air from a larger scuba tank. The adapter fitting (not shown) is attached to the scuba tank by the yoke  10  and screw  1 . The swivel fitting  3  is attached to a one way check valve (not shown) of a regulator  66  that is attached to the small scuba tank. In an embodiment, the small scuba tank is a “Spare Air” tank available from Submersible Systems, Inc. of Huntington Beach, Calif. 
   The adapter assembly  12  is attached to the small scuba tank by turning the cam ring  5  which causes the swivel fitting  3  to rotate and thread onto the check valve. As discussed in more detail below, turning the cam ring  5  to attach the adapter assembly  12  to the check valve of the regulator  66  automatically seals a vent hole. Thus, the cam ring  5  is simultaneously used to seal the vent  14  (shown in  FIG. 7 ) and to screw the adapter assembly  12  to the check valve. With the vent sealed, the small scuba tank can then be filled with compressed air from the scuba tank. 
   After filling the small scuba tank, the adapter  12  is detached from the regulator  66  by turning the same cam ring  5  to unscrew the swivel fitting  3  from the check valve. As discussed in more detail below, turning the cam ring  5  to detach the swivel fitting  3  from the regulator  66  automatically unseals the vent  14  and releases the pressure on the threads of the swivel fitting  3 . By continuing to turn the cam ring  5 , the swivel fitting  3  is unscrewed from the check valve. Thus, turning the cam ring  5  automatically releases the pressure in the adapter assembly  12  before unscrewing the swivel fitting  3  from the check valve. Although the adapter assembly  12  can be used to fill a small scuba tank with compressed air from a larger scuba tank, an artisan will recognize from the disclosure herein that the invention is not so limited. In fact, the adapter assembly can be used to transfer fluids between pressurized devices regardless of the relative sizes of the devices. 
   Referring again to  FIGS. 6 and 7 , the vent  14  in the swivel fitting  3  selectively allows a pressurized fluid (not shown) to flow in or out of the fluid passage  24 . The swivel fitting  3  further comprises a moveable pin  9  formed from a semi-elastic material such as nylon configured, sized and positioned in the vent  14  so as to prevent fluid from flowing through the vent  14  when the pin  9  is pressed into the vent  14 . An embodiment of the pin  9  is described in greater detail below with respect to  FIG. 11 . The cam ring  5  is configured to slide over the swivel fitting  3  and the vent  14 . The cam ring  5  is held in place with the retaining ring  6  positioned in slot  30  so that the cam ring  5  is allowed to rotate over the swivel fitting  3 . As will be discussed in more detail below, the cam ring  5  is configured to press down on the pin  9  as it is rotated over the swivel fitting  3 . 
   The attached Appendix includes a presentation with photographs and text demonstrating a use of the adapter assembly according to an embodiment of the invention. The Appendix forms a part of the application. 
     FIG. 8  is a detailed schematic of the adapter fitting  2  shown in  FIG. 7 , according to an embodiment of the invention. The adapter fitting  2  comprises an adapter interface  22  configured to engage a first pressurized device (not shown) and to allow a fluid (not shown) to pass between the first pressurized device and the first end  16  of the fluid passage  24 . 
     FIG. 9  is a detailed schematic of the swivel nut  4  shown in  FIG. 7 , according to an embodiment of the invention. The swivel nut  4  may comprise internal screw threads  26  configured to engage the threads of the adapter fitting  2  shown in  FIG. 7 . 
     FIG. 10  is a detailed schematic of the swivel fitting  3  shown in  FIG. 7 , according to an embodiment of the invention.  FIG. 10  illustrates the slot  30  and the fluid passage  24  through the swivel fitting  3 .  FIG. 10  also shows an approximate representation of the shape and size of the vent  14  through the side of the swivel fitting  3 . In an exemplary embodiment, the upper diameter of the vent  14  is approximately 0.25 inches or larger and is configured to receive and to be sealed by the pin shown in  FIG. 11 . 
     FIG. 11  is a cross-sectional (through the center) side view schematic of the pin  9  shown in  FIG. 7 , according to an embodiment of the invention. The dimensions are in inches and are for exemplary purposes. As shown, the pin  9  is configured and sized so as to be positioned into the vent hole  14  shown in  FIG. 10  and to seal the vent hole  14  when pressed into the vent hole  14  by the cam action of the cam ring  5  shown in  FIG. 7 . Although not shown, a top view of the entire pin  9  (i.e., not a cross-section of the pin  9 ) shown in  FIG. 7  would be circular having a diameter of approximately 0.25 inches. In a preferred embodiment, the pin  9  comprises nylon. 
     FIG. 12  is a detailed schematic of the cam ring  5  shown in  FIG. 7 , according to an embodiment of the invention. A portion of the inside diameter of the cam ring  5  is removed to form a recessed area  20  configured to fit over the pin  9  shown in  FIG. 7 . The cam ring  5  can also be formed or molded to create the recessed area  20 . The recessed area  20  is tapered or formed in the shape of a “half moon” so as to provide a cam action wherein rotating the cam ring  5  around the swivel fitting  3  presses the pin  9  into the vent  14  shown in  FIG. 10  and prevents the fluid (not shown) from passing between the vent  14  and the fluid passage  24 . 
     FIG. 13  is a cross-sectional cut view of the swivel fitting  3  shown in  FIG. 7  illustrating the cam ring  5  positioned around the swivel fitting  3  and over the pin  9  and vent  14 . As shown, the recessed area  20  of the cam ring  5  is positioned so as to allow fluid (not shown) flowing in the fluid passage  24  to flow around the pin  9  and out of the vent  14 . 
     FIG. 14  is a cross-sectional cut view of the swivel fitting  3  shown in  FIG. 7  illustrating the cam ring  5  positioned around the swivel fitting  3  and over the pin  9  and vent  14 . As shown, the recessed area  20  of the cam ring  5  is positioned so as to push down on the pin  9  and prevent fluid flowing in the fluid passage  24  from flowing out of the vent  14 . 
   Although the foregoing invention has been described in terms of certain preferred embodiments, other embodiments will be apparent to those of ordinary skill in the art. Additionally, other combinations, omissions, substitutions and modifications will be apparent to the skilled artisan in view of the disclosure herein. Accordingly, the present invention is not intended to be limited by the reaction of the preferred embodiments, but is to be defined by reference to the appended claims.

Technology Category: 7