Abstract:
A valve for limiting excess flow includes a one-piece body having a seat, a diaphragm, and a plurality of flexible legs attaching the seat to the diaphragm and spacing the seat from the diaphragm, wherein the legs flex to seat the diaphragm within the seat if excess flow exceeds a limit.

Description:
BACKGROUND OF THE INVENTION 
     The present invention generally relates to an excess flow check valve that permits fluid flow through a flow line if the flow is below a predetermined flow rate but minimizes the flow line if the flow rate rises above the predetermined limit to prevent uncontrolled flow or discharge of fluids. 
     Excess flow valves are typically used in a capsule to facilitate its installation in various flow lines, fittings, pipe systems, appliances and the like. The excess flow valve actuates in response to a high or a low differential pressure between the upstream pressure and downstream pressure of the capsule, which usually have four portions, a seat, a housing, a valve plate or body, and a spring or magnet to bias the valve plate. The capsule may be inserted in various flow passageways including a valve body, a connector fitting, a hose fitting, a pipe nipple, a tube, an appliance and other similar installations to provide excess flow protection. 
     A capsule facilitates assembly of the individual components into a self-contained compact package, provides for easy insertion of the capsule into a fitting or tube, provides means for substantially restricting flow, provides means for allowing small leakage flow for automatic valve resetting, precisely positions and retains the components of the valve for proper operation, provides a unique structure for coupling the two capsule components, permits flow testing as a capsule to verify performance and provides a compact configuration to minimize the size, diameter and length required to accommodate the capsule. 
     According to an embodiment described herein, a valve for limiting excess flow includes a one-piece body having a seat, a diaphragm, and a plurality of flexible legs attaching the seat to the diaphragm and spacing the seat from the diaphragm, wherein the legs flex to seat the diaphragm within the seat if excess flow exceeds a limit. 
     SUMMARY OF THE INVENTION 
     The capsule described herein achieves its purpose by replacing the magnet, plate and housing with a single piece having a flexible diaphragm. Legs attaching to the diaphragm have a small cross-sectional area to allow for more efficient flow through the capsule. Also, the capsule is manufactured using a silicone or rubber that is more common, and less costly than a rare earth magnets, which may be required for biasing a valve body used in other excess flow valves. Also, the capsule described herein eliminates a need for assembling as the capsule is made in one-piece. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a gas coupling pipe including an excess flow capsule. 
         FIG. 2  shows a first embodiment of an excess flow capsule used in the pipe of  FIG. 1  in a first position. 
         FIG. 3  shows the first embodiment of an excess flow capsule used in the pipe of  FIG. 1  in a second position. 
         FIG. 4  shows a second embodiment of an excess flow capsule used in the pipe of  FIG. 1  in a first position. 
         FIG. 5  shows the second embodiment of an excess flow capsule used in the pipe of  FIG. 1  in a second position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the Figures, gas connector  5  includes a fluid pipe  10 , includes an inlet coupling  15 , an outlet coupling  20 , and an excess flow capsule  25 . The pipe may carry different fluids, such as natural gas, or other gases or liquids. The capsule  25  is molded or cast in one-piece of a flexible, fluid resistant material such as rubber or silicone or the like. 
     The pipe  10 , which may have corrugations  30 , has a non-corrugated area  35  that holds the capsule  25 , which is bounded by a radially inwardly depending shoulder  40 , which may be a groove, and an expanded area  45  for interacting with the excess flow capsule  25  as will be discussed infra. The pipe  10  extends along an axis  47 . 
     The expanded area  45  has an increased diameter D e  relative to the diameter D c  of the non-corrugated area  35  to provide more area for fluid flow around and through the capsule  25 . 
     The inlet coupling  15  and the outlet coupling  20  each have a housing  50  that surrounds flared ends  55 , as are known in the art, of the pipe  10 . The housings  50  each have an internal thread  60  for mating with external threads (not shown) of a gas supply line (not shown) at the inlet coupling  15  and a with the external threads (not shown) of an appliance (not shown) at the outlet coupling  20 . 
     Referring now to  FIGS. 2 and 3 , the one-piece capsule  25  has three basic components, a valve seat  65 , two or more legs  70 , and a valve plate  75  or diaphragm. The valve seat  65 , which is generally cylindrical, has a centrally disposed flow passageway or orifice  80 , has a base  85  with a diameter D b  and upstream portion  90  extending from said base  85  and having a diameter D u  from which the integral flexible legs  70  extend in an upstream direction therefrom. The diameter D b  is less than the diameter D u  to allow the legs to bow radially outwardly during operation. The valve seat  65  has an internal shoulder  95 , which may have a tapered portion  97  for seating the valve plate  75 , that is spaced from the top  100  of the upstream portion  90  a distance that correlates to a height of an edge  105  extending about the periphery  110  of the circular valve plate  75 . 
     The legs  70  each have curved portions  115  that allow the legs  70  to blend into the top  100  of the upstream portion  90  of the valve seat  65  and extend upstream towards to the valve plate  75 . The legs terminate in a curved portion  120 . The curved portion  120  bends at about a 90° angle relative to the leg  70  and the valve plate  75 . The valve plate  75  (also known as a plug or a diaphragm) may have an angled shoulder  122  on an outside downstream portion, which mates with the taper portion  97  of the shoulder  95  to minimize flow as will be discussed infra. 
     A notch  125  may be cut in the valve plate  75  and a corresponding notch  130  may be cut in the shoulder  95  to allow the capsule  25  to reset itself if an excess flow condition (i.e., where flow exceeds a given limit as if there is no downstream back pressure) no longer exists. The valve plate  75  may also have a pin-hole  135  cut through it for the same purpose. 
     During normal operation in which there is no excess flow, fluid, such as natural gas, flows through the pipe  10 , around the valve plate  75 , between the legs  70  and through the flow passageway  80 . Because the expanded area  45  increases the area of flow of gas around the capsule  25  and because there is a lot of room around the valve plate  75 , there is relatively little pressure drop as the fluid flows by the valve plate  75 . Legs  70 , therefore, do not flex and the valve plate  75  stays in position A (see  FIG. 2 ) and the curved portion  120  is still at about 90°. 
     If there is a breakage or the like in the pipe  10 , gas flow through the capsule  25  may not be limited by an appliance (not shown) and there is a risk that gas may flow above a given limit without obstruction. The pressure drop downstream of the cartridge  25  increases greatly due to the increased flow and the valve plate  75  is induced towards the valve seat  65  as the legs  70  flex to seat against the shoulder  95  as shown in position B (see  FIG. 3 ) The curved portion  120  of the legs  70  increases in bend from about 90° to about 180° (the leg doubles over) and migrates down the leg  70  as the valve plate moves to be seated in position B. In other words, each leg  70  flexes about the curved portion  120  above the valve plate as the valve plate moves to position B. Each leg  70  bends radially inwardly until there is an upper portion  140  of the leg  70  (see  FIG. 2 ) adjacent and may become parallel to a lower portion  145  of the same leg  70 . The lower portion  145  of the leg may bow radially outwardly away from the axis and the upper portion  140  of the leg may bow radially inwardly towards the axis  47 . 
     Fluid may leak through the notches  125 ,  130  or hole  135  to allow pressure to equalize upstream and downstream of the valve plate  75 . After the pressure is equalized, such as if the pipe  10  is fixed, the flexibility of the legs  70  allows them to return the valve plate to return to position A, thereby allowing gas to flow through the cartridge  25 . 
     Referring now to  FIGS. 4 and 5 , another embodiment of the cartridge  25  is shown. The main difference between the two embodiments is that the legs  200  are mounted between the valve plate  75  and the valve seat  65 . In position C as shown in  FIG. 4 , the legs  200  are integrally mounted to the bottom  205 , of the valve plate and integrally mounted to a radially inner surface  210  of the shoulder  95  below the tapered portion  97 . A center portion  215  of the legs  200  may be bowed radially inwardly relative to the radially inner surface  210  and the bottom  205  and is designed to flex radially inwardly towards the axis  47 . 
     During normal operation in which there is no excess flow, fluid, such as natural gas, flows through the pipe  10 , around the valve plate  75 , between the legs  200  and through the flow passageway  80 . Because the expanded area  45  increases the area of flow of gas around the capsule  25  and because there is a lot of room around the valve plate  75  and around the legs  200 , there is relatively little pressure drop as the fluid flows by the valve plate  75 . Legs  200 , therefore, do not flex and the valve plate  75  stays in position C (see  FIG. 4 ). 
     As above, if there is a breakage or the like in the pipe  10 , gas flow through the capsule  25  may not be limited by an appliance (not shown) and there is a risk that gas may flow above a given limit without obstruction. The pressure drop downstream of the cartridge  25  increases greatly due to the increased flow and the valve plate  75  is induced towards the valve seat  65  as the legs  200  flex to seat against the shoulder  95  (or surfaces  97  and  122 ) as shown in position D in  FIG. 5 . The center portion  215  of the legs  70  increases from its bowed position in position C until the valve plate is seated against the shoulder  95  in the valve seat  65 . 
     As above, fluid may leak through the notches  125 ,  130  to allow pressure to equalize upstream and downstream of the valve plate  75 . After the pressure is equalized, such as if the pipe  10  is fixed, the flexibility of the legs  70  allows them to return the valve plate to return to position A, thereby allowing gas to flow through the cartridge  25 . 
     Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments. 
     The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.