Patent Application
20150219232
The present invention generally relates to an excess flow valve that permits fluid flow through a flow line if the flow is below a predetermined flow rate but minimizes the flow 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 acts in response to a high or a low differential pressure between the upstream pressure and downstream pressure of the capsule. In one known configuration, the excess flow valve is comprised of four components including a housing, a seat, 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, a male iron pipe (MIP), a female iron pipe (FIP), an appliance and other similar installations to provide excess flow protection.
These spring and magnet configurations can be disadvantageous from a cost and assembly perspective due to the number of components. The magnet is especially costly and difficult to procure. Further, the magnet poses constraints on the design of the capsule and excess flow valve that make it difficult to lower cost and provide improvements.
According to one exemplary embodiment, an assembly for limiting excess flow includes a housing having an internal bore defined by a first diameter, a seat held fixed within the internal bore, and a diaphragm defined by a second diameter that is less than the first diameter. The seat provides a sealing surface and the diaphragm is coupled to the seat by at least one leg. The diaphragm is spaced apart from the sealing surface during normal flow conditions and is in engagement with the sealing surface when a predetermined flow condition is exceeded.
In another embodiment according to the previous embodiment, the at least one leg comprises a plurality of legs that are circumferentially spaced apart from each other.
In another embodiment according to any of the previous embodiments, the legs are moveable between a first position during normal flow conditions and are collapsed to a second position when the predetermined flow condition is exceeded.
In another embodiment according to any of the previous embodiments, the diaphragm comprises a solid body having an upstream side and a downstream side, and wherein the legs have a first end attached to the downstream side and a second end attached to the seat.
In another embodiment according to any of the previous embodiments, the second diameter comprises an outermost diameter of the solid body and wherein the solid body is defined by a minimum diameter at the downstream side with a tapered surface extending between the outermost diameter and the minimum diameter.
In another embodiment according to any of the previous embodiments, the seat comprises a rigid ring body having an upstream end face and a downstream end face, the ring body having an inner opening that is aligned within the internal bore, and wherein the downstream end face is seated on the shoulder with the sealing surface comprising a tapered surface extending radially inward from the upstream end face.
In another embodiment according to any of the previous embodiments, the diaphragm includes an outermost peripheral edge that defines the second diameter and wherein the inner opening of the seat defines a surface that extends from a downstream end of the tapered surface to the downstream end face of the seat, and wherein during normal flow conditions fluid flows around the outermost peripheral edge of the diaphragm and through a gap formed between the seat and the diaphragm, and then through openings between the legs and through the inner opening of the ring body.
In another embodiment according to any of the previous embodiments, when the predetermined flow condition is exceeded, the diaphragm engages the tapered surface to prevent flow through the inner opening of the ring body.
In another embodiment according to any of the previous embodiments, the ring body includes a plurality of recesses that receive ends of the legs.
In another embodiment according to any of the previous embodiments, the recesses comprise at least partially curved surfaces, and wherein the ends of the legs comprise enlarged bulbous ends that engage the curved surfaces.
According to another exemplary embodiment, a method of forming an excess flow valve includes molding first and second housing pieces, connecting the first and second housing pieces together to define an internal bore, coupling a diaphragm to a seat with one or more legs such that the diaphragm is moveable relative to the seat, and fixing the seat within the internal bore.
In another embodiment according to any of the previous embodiments, additional steps include molding the first and second housing from a plastic material and forming the at least one leg from a flexible material.
In another embodiment according to any of the previous embodiments, additional steps include forming a plurality of recesses in the seat and inserting a downstream end of each leg into one recess.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
The fitting 10 includes a housing 14 having an internal bore 16 defining a central axis A and extending from an upstream end 18 to a downstream end 20. The bore 16 provides a shoulder 22 within the internal bore 16. A seat 24 is held fixed within the internal bore 16 and provides a sealing surface 26. A diaphragm 28 is coupled to the seat 24 by one or more legs 30. The diaphragm 28 is spaced apart from the sealing surface 26 during normal flow conditions and is in engagement with the sealing surface 26 when a predetermined flow condition is exceeded. This will be discussed in greater detail below.
The diaphragm 28 comprises a solid body 32 having an upstream side 34 and a downstream side 36. The legs 30 have a first end 38 attached to the downstream side 36 and a second end 40 attached to the seat 24. The legs 30 are circumferentially spaced apart from each other about the central axis A. Gaps or openings 42 are formed between adjacent legs 30. The legs 30 are moveable between a first position (
The solid body 32 comprises a shuttle portion of the excess flow valve 12 that is naturally positioned to allow for flow through the valve 12 during normal flow conditions. When a certain flow pressure is reached, i.e. the predetermined flow condition is exceeded, the pressure on the shuttle portion overcomes the resistance of the legs 30 and the shuttle portion will press against the sealing surface 26 of the seat 24 to prevent fluid from being released to the external environment in an excess flow condition. After the pressure is equalized on both sides of the shuttle portion, the resilient force of the legs 30 causes the shuttle portion to return to the original position such that fluid can again flow through the valve 12.
In one example, the solid body 32 comprises a cup-shape with the upstream side 34 comprising a concave surface against which flow pressure F is exerted. The solid body 32 has a lip 44 that extends about the central axis A to form a peripheral edge 46 of the solid body 32. The solid body 32 on the upstream side 34 curves inwardly from the lip 44 to a bottom 48 of the cup-shape. The peripheral edge 46 defines a maximum of an outermost diameter D1 of the solid body 32. The bottom 48 defines a minimum diameter D2 of the solid body 32. The solid body 32 includes a tapered surface portion 50 that extends inwardly from the downstream side of the lip 44 toward the bottom 48 at the minimum diameter.
In one example, the first ends 38 of the legs 30 are attached to a downstream side of the bottom 48 of the solid body 32, and the legs 30 are curved in a radially inwardly direction during normal flow conditions as shown in
As shown in
In one example, the seat 24 comprises a rigid ring body 60 having an upstream end face 62 and a downstream end face 64. The ring body 60 has an inner opening 66 that is aligned with the internal bore 16. In one example, the inner opening 66 is concentric with the axis A. The downstream end face 64 is seated directly on the shoulder 22 with the sealing surface 26 comprising a tapered surface 68 that extends in a radially inward direction from the upstream end face 62. The lip 44 of the solid body 32 is seated against the upstream end face 62 during an excess flow condition.
The inner opening 66 of the seat 24 defines a surface 70 that extends from a downstream end of the tapered surface 68 to the downstream end face 64. During normal flow conditions fluid flows around the outermost peripheral edge 46 of the lip 44 of the diaphragm 28 and through a gap 72 formed between the seat 24 and the diaphragm 28. The fluid then flows through the openings 42 formed between adjacent legs 30 and through the inner opening 66 of the ring body 60 to exit the downstream end 20 of the housing 14. When the predetermined flow condition is exceeded, such as during an excess flow condition, the diaphragm 28 engages the tapered surface 68 to prevent flow through the inner opening 66 of the ring body 60.
As shown in
In one example, the housing 14 (see
One exemplary method of forming the excess flow valve 12 includes the steps of molding the first 90 and second 94 housing pieces, connecting the first 90 and second 94 housing pieces together to define the internal bore 16, coupling the diaphragm 28 to the seat 24 with one or more legs 30 such that the diaphragm 28 is moveable relative to the seat 24, and fixing the seat 24 within the internal bore 16.
In one example, the method includes the steps of molding the first 90 and second 94 housings from a plastic material and forming the legs 30 from a flexible material.
The subject invention offers several advantages over prior designs. The subject invention offers a reduction in components as compared to a four-piece configuration (eliminating a brass fitting, a brass seat, a plate and replacing a plastic housing, for example), resulting in a simpler design. A two-piece configuration is provided with the valve being co-molded or molded in during a two-shot molding process. The legs of the diaphragm have a smaller cross-sectional area as compared to the previous plastic housing, which allows for more efficient flow through the valve. Also, the diaphragm can be manufactured from an elastomer or thermoplastic material with similar properties, with a plastic or rigid base for stability during assembly.
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.
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.
