Patent Description:
The present disclosure relates to the field of valves, more particularly to control valves used in fluid based control circuits used to initiate and control the operation of fluid operated control components and other fluid operated components, for example pressure relief and check valves connected to a fluid circuit, the valve configured to move from a closed to an open position and allow fluid in the circuit to pass therethrough, as well as be piloted open to vent a pressure downstream of the valve, i.e., at the valve outlet.

Certain fluid valves, for example a prior check valve <NUM> as shown in <FIG> and <FIG>, which is used in fluid circuits which control the operation of, or operate, fluid controlled or operated equipment, include a first fluid port <NUM> functionable as an upstream inlet, a second fluid port <NUM> functionable as a downstream outlet, and, when the pressure in the first fluid port <NUM> exceeds a predefined pressure, also known as the "cracking pressure", a recessed annular seal sleeve <NUM> having a seat contact recessed from the outer circumferential wall thereof actuates to selectively communicate fluid and pressure between the first fluid port and the second fluid port. Thus, the valve <NUM> can operate as a check valve. In one construct, these valves <NUM> include a main body <NUM> having a central bore <NUM>, a counterbore <NUM> extending inwardly of an outer wall <NUM> of the main body <NUM> and terminating at an annular seat face <NUM> , and a cap <NUM> extending over the outer wall <NUM> into which the counterbore extends and which seals off the counterbore <NUM>. The cap <NUM> includes a boss <NUM> extending inwardly of the counterbore <NUM> and terminating at a boss face <NUM>. A seat ring <NUM> is disposed within the counterbore <NUM> and against the annular seat face <NUM>, and a cage <NUM> functioning as a cage extends between the boss face <NUM> of the cap <NUM> and the seat ring <NUM>. The recessed annular seal sleeve <NUM> is engaged against the back side <NUM> of the seat ring <NUM> opposite to the front side <NUM> thereof facing the annular seat face <NUM>, and a spring <NUM> extends between the cap <NUM> and the recessed annular seal sleeve <NUM> to bias the recessed annular seal sleeve <NUM> against the back side <NUM> of the seat ring <NUM>. The recessed annular seal sleeve <NUM> faces the portion of the central bore <NUM> of the body which is fluidly coupled to the first fluid port <NUM>. When the pressure in the first fluid port <NUM> exceeds the cracking pressure, the recessed annular seal sleeve <NUM> backs away from the back side <NUM> of the seat ring <NUM>, and allows fluid and pressure communication between the first fluid port <NUM> and the second fluid port <NUM>. The seat ring <NUM> includes a circumferential outer surface <NUM> generally of the same geometry of the counterbore inner wall <NUM>, into which extends a circumferential seal groove <NUM> having a seal ring, such as an O-ring <NUM> therein. The O-ring <NUM> contacts the base of the circumferential seal groove <NUM> and the counterbore inner wall <NUM>, and the width of the O-ring <NUM>, and thus of the circumferential seal groove <NUM>, is dictated by the maximum expected pressure difference between the first fluid port <NUM> and the second fluid port <NUM>, plus a safety factor, over the installed life of the valve <NUM>. The thickness "t" of the annular projections or flanks of the seat ring <NUM> between the opposed front side <NUM> or back side <NUM> of the seat ring <NUM> and the circumferential seal groove <NUM> are likewise selected to ensure that the seat ring <NUM> has sufficient strength to withstand the maximum expected pressure difference between the first fluid port <NUM> and the second fluid port <NUM>, plus a safety factor without failing and allowing the O-ring <NUM> to become free of the circumferential seal groove <NUM> and thereby allow uncontrolled flow of fluid and pressure between the between the first fluid port <NUM> and the second fluid port <NUM>. Additionally, this requires the seat ring <NUM> be manufactured of a relatively rigid plastic material, such as Delrin® 511P or a PEEK material.

To ensure that the seat ring <NUM> is biased against the annular seat face <NUM> and thereby ensure that the seat ring <NUM> cannot move when the recessed annular seal sleeve <NUM> engages it, i.e., there is no free space between the seat ring <NUM> and the annular seat face <NUM> or between the seat ring <NUM> and the cage <NUM> when the valve is assembled, the cage <NUM> is sized to bias the seat ring <NUM> against the annular seat face <NUM> upon assembly of the valve <NUM>. The seat ring <NUM> is a solid right annular body, configured to withstand extremes of pressure, and has limited compressibility. To ensure the biasing, the boss <NUM>, and thus boss face <NUM> on the cap <NUM>, which is connected to the main body <NUM> by a plurality of fasteners extending through opening therethrough (not shown) and corresponding threaded openings (not shown) into which threaded fasteners are secured, <NUM> presses an annular face <NUM> of the cage <NUM> against the back side <NUM> of the seat ring <NUM> and thus presses the seat ring <NUM> against the annular seat face <NUM>. Because of the machining and fabricating tolerance ranges of the depth of the counterbore <NUM> from the cap end thereof (where the counterbore begins at outer wall <NUM> of the main body <NUM>) to the annular seat face <NUM>, and thus the distance between the annular seat face <NUM> and the outer wall <NUM> of the main body <NUM> into which the counterbore <NUM> extends, as well as the machining and fabricating tolerance range on the height of the cage <NUM>, on the height of the boss <NUM> and on the thickness of the seat ring <NUM>, to ensure proper loading of the seat ring <NUM> against the annular seat face <NUM>, a purposefully created tolerance stack gap 18a (<FIG>) is present between the inner surface <NUM> of the cap <NUM> and the adjacent outer surface <NUM> of the main body <NUM> surrounding the counterbore <NUM>, i.e., at all ranges of the tolerances of these parts, the tolerance stack gap 18a is present. Without the tolerance stack gap, the valve assembler cannot ensure that the annular face <NUM> of the cage <NUM> biases the seat ring <NUM> against the annular seat face <NUM> such as when the seat ring <NUM>, cage <NUM> and height of the boss <NUM> are at their minimum dimensions and the counterbore <NUM> is at its maximum depth dimension, but still within allowed dimensional tolerances. Thus, the gap is purposefully present to allow the assembler of the valve to a visual indicator on the exterior of the valve that the seat ring <NUM> is properly pushed or biased physically annular seat face <NUM>. If the inner surface <NUM> of the cap <NUM> is secured against the base of the outer wall <NUM>, one is unsure whether the cage <NUM> is actually biased against the seat ring <NUM> and simultaneously biasing the seat ring <NUM> against the annular seat face <NUM>. As a result, when this tolerance stack gap 18a is present between the inner surface <NUM> of the cap <NUM> and the base of the outer wall <NUM>, the ambient fluids around the installed location of the valve <NUM> are able to enter into the tolerance stack gap, and where the valve is located in a corrosive environment such as an offshore or subsea environment and exposed to seawater, cause corrosion, and eventually, stress corrosion cracking of the cap <NUM> or valve body <NUM>, resulting in failure of the valve <NUM> and the need to replace the valve <NUM>. Because the failure of the valve <NUM> will affect the integrity of the fluid circuit to which it is connected, for example a fluid control circuit for an offshore or subsea blowout preventer, the integrity of the ability to close the rams of the blowout preventer can be affected. Therefore, the valves <NUM> of this construct may need to be prematurely replaced prior to the expiration of their useful life and well before the onset of stress corrosion cracking, well before the likelihood of valve failure.

<CIT> discloses a solenoid having an annular magnet structure held within a body by a cover, and the magnet structure is surrounded on three sides by a seal. The seal includes an extending lip on the end thereof distal to the cover, and the lip contacts the interior surface of the body.

<CIT> discloses a valve according to the preamble of claim <NUM> and having a pilot piston which is disposed in a pilot piston bore. An end cap includes a boss extending inwardly of the pilot piston bore.

<CIT> discloses a fuel pump having an internal member including a projecting portion, a portion of which surrounds a fuel passage, within which a piston reciprocates.

<CIT> discloses a valve including a body having a first inlet, a second inlet and an outlet. The valve further includes a shuttle disposed in the body. The shuttle is movable within the body between a first position and a second position, wherein the first inlet is open and the second inlet is closed when the shuttle is in the first position, and wherein the first inlet is closed and the second inlet is open when the shuttle is in the second position. In addition, the valve includes a non-metallic seal assembly disposed adjacent each inlet.

A valve in accordance with the claims is provided.

A valve includes a valve body including a first fluid port opening from the valve body, a second fluid port opening from the valve body, and an interior passage selectively fluidly connecting the first fluid port and the second fluid port, a bore extending inwardly of a first wall of the valve body and having an annular first seat securement surface extending around the an interior passage intermediate of the first fluid port and the second fluid port, a cage disposed in the bore, the cage having an annular second seat securement surface and an opposed first annular surface, the annular second seat securement surface facing the annular first seat securement surface, a cover extending over the first wall of the valve body and the opening of the bore thereof, the cover including a cage engagement surface contacting the first annular surface, and an annular seat having a main body having an opening therethrough and a first seat surface facing and contacting the annular first seat securement surface of the valve body and a second seat surface, facing away from the first seat surface, the second seat surface comprising a first annular region having a first elevation and a second annular region different than the first annular region, and the second annular region comprises at least one projection projecting from the seat to an elevation greater than the first elevation and contacting the annular second seat securement surface.

In an additional aspect, not forming part of the claimed invention, a valve includes a valve body including a first fluid port opening from the valve body, a second fluid port opening from the valve body, and an interior passage selectively fluidly connecting the first fluid port and the second fluid port, a bore extending inwardly of a first wall of the valve body and having an annular first seat securement surface extending around the an interior passage intermediate of the first fluid port and the second fluid port, a cage disposed in the bore, the cage having an annular second seat securement surface and an opposed first annular surface, the annular second seat securement surface facing the annular first seat securement surface, a cover extending over the first wall of the valve body and the opening of the bore thereof, the cover including a cage engagement surface contacting the first annular surface, and an annular seat having a main body having an opening therethrough and a first seat surface facing and contacting the annular first seat securement surface of the valve body and a second seat surface, facing away from the first seat surface, the second seat surface comprising a first annular region having a first elevation and a annular seat including a first compression portion and a second compression portion, wherein the first and second compression portions have different compressibility.

It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, may admit to other equally effective embodiments.

Referring initially to <FIG>, a valve, here configured as a non-gapped check valve <NUM> functional as, for example, a pressure relief valve, is provided, wherein the first cover <NUM> corresponding to the cap <NUM> of the valve <NUM> of <FIG> and <FIG> comes into contact with the adjacent lower cover wall <NUM> of the body <NUM> of the non-gapped check valve <NUM>, such that no gap is present between the first cover <NUM> and the adjacent annular cover wall <NUM> of the body <NUM>, resulting in reduced corrosion of the components and a longer useable valve lifetime. Here, this capability is provided by use of a conforming seat ring <NUM> (<FIG>) having regions of different compressibility. In one aspect, to provide the regions of different compressibility, the conforming seat ring <NUM> includes a plurality of projections <NUM> extending therefrom on the side thereof facing away from the annular seat wall <NUM> (corresponding to the annular seat ledge <NUM> of valve <NUM>) of the non-gapped check valve <NUM>, which projections <NUM> are compressible to provide a physical or dimensional relief for the tolerance stack of the valve components, ensuring that the surface of the first cover <NUM> abuts and contacts the adjacent annular cover wall <NUM> of the body <NUM> over the range of the tolerance stack of the interior components of the valve and the cage <NUM> of the non-gapped check valve <NUM> is in contact with the conforming seat ring <NUM>, and the conforming seat ring <NUM> is thus biased into contact with the annular seat wall <NUM> when the non-gapped check valve <NUM> is assembled, over the entire range of the dimensional tolerance of the components thereof. The projections <NUM> may be in a limited annular region or radial span of the cage facing side of the conforming seat ring <NUM>, and thus the conforming seat ring <NUM> has different compressibility at different annular regions thereof. Additionally, the annular region of lower compressibility may be considered to be at a different elevation of the conforming seat ring <NUM>, i.e., extending outwardly from the annular cap facing surface (second annular face <NUM>) of the conforming set ring, as well as in a different annular region of the annular cap facing surface (second annular face <NUM>) of the conforming seat ring <NUM>.

In one aspect, as shown in <FIG>, the entire conforming seat ring <NUM> is composed of the same material having the same material properties, including the projections <NUM> thereof. However, the projections <NUM> extend outwardly from the second annular face <NUM> of the conforming seat ring <NUM> and are spaced from one another, both radially and, in part, circumferentially, across the second annular face <NUM>. In result, the projections <NUM>, and the open spaces between them, together in aggregate form a region that has greater compressibility, in other words is more readily compressed, than that of the remaining bulk of the conforming seat ring <NUM>. Additionally, the volume or bulk of the projections <NUM> can, when pressed inwardly of the conforming seat ring <NUM>, deform in a radial direction into the space between the adjacent projections <NUM> in the radial direction of the conforming seat ring <NUM> second annular surface <NUM>, and thus have greater compressibility than that of the remaining bulk of the conforming seat ring <NUM>.

Referring to <FIG>, similarly to the non-gapped check valve <NUM> of <FIG> and <FIG>, the non-gapped check valve <NUM> includes the body <NUM> manufactured, when for subsea service, of for example stainless steel, duplex stainless steel, or CRA (nickel alloy), having a generally rectangular outer contour provided of four generally planer outer faces, first through fourth outer surfaces <NUM>, <NUM>, <NUM> and <NUM>, bounded at their opposed ends by a lower cover wall <NUM> and an upper cover wall <NUM>. A first cover <NUM> extends over the lower cover wall <NUM> (<FIG>) , a third adaptor <NUM> extends partially over the second cover wall <NUM>, a first adaptor <NUM> extend spatially over the first outer surface <NUM> and a second adaptor <NUM> extends partially over the fourth outer face <NUM>. Each of first cover <NUM>, and first, second and third adaptors <NUM>, <NUM>, <NUM> are connected the body <NUM> by a fastening paradigm, here by a plurality of threaded fasteners <NUM> extending through openings in the corresponding one of the first cover <NUM>, and the first, second and third adaptors <NUM>, <NUM>, <NUM> and into corresponding threaded apertures provided therefor (not shown) extending inwardly of the first and fourth outer surfaces <NUM> and <NUM>, and the lower cover wall <NUM> and an upper cover wall <NUM>.

Referring to <FIG> and <FIG>, first cover <NUM> includes a main body <NUM> having a generally rectangular perimeter wall <NUM> having generally the same dimensions as the rectangular, in section, body <NUM>, and first cover boss <NUM> extending therefrom and inwardly of a counterbore <NUM> extending inwardly of the cover wall <NUM> of the body <NUM>. A first annular boss <NUM> extends from the counterbore facing side of the main body <NUM> of the first cover <NUM> adjacent the outer perimeter of the first cover boss <NUM>. The outer circumferential surfaces of the first cover boss <NUM> and first annular boss <NUM> together extend as an outer first cover wall <NUM> of a generally right cylindrical profile and having an outer diameter on the order of <NUM> to <NUM> smaller than the inner diameter of the generally right cylindrical inner counterbore wall <NUM>. An annular circumferential limit wall <NUM> extends circumferentially around the first cover boss <NUM> and is engaged against the lower cover wall <NUM> of the body <NUM> of the non-gapped check valve <NUM> with no gap therebetween. A first cover outer seal groove <NUM> extends inwardly of the outer first cover wall <NUM> and a first cover seal ring <NUM> is located therein and is squeezed between the base <NUM> of the first cover outer seal groove <NUM> and the facing inner surface of the inner counterbore wall <NUM>. In this first cover <NUM>, a second first cover boss <NUM> extends from the main body <NUM> in the direction opposed to the first cover boss <NUM>. A spring bore <NUM>, here configured as a generally right cylindrical blind bore or blind hole, extends inwardly of a first cover loading surface <NUM> extending within the inner circumference of the first cover boss <NUM> and generally centered thereon. The first cover <NUM> also includes a first cover loading surface <NUM> which is generally circular, and is bounded at its outer circumference by an inner annular guide wall <NUM> which forms the inner circumferential limit of the first annular boss <NUM> and the outer circumferential limit of the first cover loading surface <NUM>, and the first annular boss <NUM> also includes an annular valve inwardly facing surface <NUM> extending from the terminus of inner annular guide wall <NUM>, distal to the first cover loading surface <NUM>, to the outer first cover wall <NUM>.

The third adaptor <NUM> includes a third adaptor cover main body <NUM> having a third adaptor cover boss <NUM> extending therefrom and into a piston bore <NUM> extending inwardly of the second cover wall <NUM> of the body <NUM>. The third adaptor cover boss <NUM> is a generally right annular member having an third adaptor boss outer circumferential surface <NUM> having a diameter on the order of <NUM> to <NUM> inches (<NUM> to <NUM>) less than the diameter of the piston bore <NUM> and terminating in a generally circular inwardly facing surface <NUM>. A generally circular outer third adaptor face <NUM> is located on the third adaptor <NUM> on the side thereof opposed to the inwardly facing surface <NUM>. An actuator bore <NUM> extends through the third adaptor <NUM> with opposed openings thereof generally centered in the inwardly facing surface <NUM> and the outer third adaptor face <NUM>. As previously described, the third adaptor <NUM> is connected to the upper cover wall <NUM> by plurality of threaded fasteners <NUM> extending through openings (not shown) in the third adaptor <NUM> and corresponding threaded apertures provided therefor (not shown) extending inwardly of the outer cover wall <NUM> and body <NUM>.

First and second adaptors <NUM>, <NUM> here are each configured to receive a threaded nipple therein, and each includes an adaptor body <NUM> having a generally rectangular outer perimeter and a generally circular, in section, female receiver portion <NUM> extending therefrom in the direction away from the body <NUM>, a lower rectangular body <NUM> and an annular outer guide surface <NUM>. A first bore <NUM> extends inwardly of the lower rectangular body <NUM>, and a second threaded bore <NUM> having an inner circumferential surface configured with threads <NUM> fluidly connected to the first bore <NUM> inwardly of the adaptor body <NUM>. As previously described, the first and second adaptors <NUM>, <NUM> are connected to their respective first and fourth outer surfaces <NUM>, <NUM>, by a plurality of threaded fasteners <NUM> extending through openings (not shown) in the adaptor bodies <NUM> of the first and second adaptors <NUM>, <NUM> and corresponding threaded apertures provided therefor (not shown) extending inwardly of the respective first and fourth outer surfaces <NUM>, <NUM> and body <NUM>. An annular seal groove <NUM> extends inwardly of the base of the lower rectangular body <NUM> and around the opening of the first bore <NUM> into the lower rectangular body <NUM>, and a seal ring <NUM> such as an O-ring is received therein and seals against the base of the annular seal groove <NUM> and the adjacent corresponding ones of the first and fourth outer surfaces <NUM>, <NUM> of the body <NUM>.

Body <NUM> is configured with fluid volumes therein, and with active components which are actuable in response to changes in pressure in at least one of the fluid volumes therein, to change a position or state of the actuable components to enable selective communication between the first bore <NUM> and the second threaded bore <NUM> of the first adaptor <NUM> and the first bore <NUM> and the second threaded bore <NUM> of the second adaptor <NUM>. Here, the non-gapped check valve <NUM> is configured to allow substantially free fluid flow from the first bore <NUM> to the second bore <NUM> when the pressure differential therebetween exceeds the cracking pressure of the valve, and block communication between the first bore <NUM> and the second threaded bore <NUM> of the first adaptor <NUM> and the first bore <NUM> and the second bore <NUM> of the second adaptor <NUM> unless the pressure in the first bore <NUM> and the second bore <NUM> of the first adaptor <NUM> exceeds that cracking pressure, for example a pressure difference of <NUM> p. Here, the cracking pressure is a function of the difference between the pressures in the first and second bores <NUM>, <NUM> and the spring constant "k" of a spring <NUM> tending to push and thus seat the modified seal sleeve <NUM> against the conforming seat ring <NUM>, such as the position thereof of <FIG>.

Referring to <FIG> and <FIG>, the counterbore <NUM> extending inwardly of the lower cover wall <NUM> terminates within the body at an annular seat wall113 which circumscribes a central flow passage <NUM> within the body <NUM>, and the central flow passage <NUM> extends therefrom in the direction of the upper cover wall <NUM>, which in turn terminates at an annular rod ledge <NUM> circumscribing a rod alignment passage <NUM> extending from its opening through the annular rod ledge into the piston bore <NUM> extending inwardly of the upper cover wall <NUM>.

The pressure activated active components include a modified seal sleeve <NUM>, the modified seal sleeve <NUM> operating as a seal sleeve having a similar function to that of the annular seal sleeve <NUM> of the valve of <FIG> and <FIG> herein. The spring <NUM> includes a lower portion of which bears against the base <NUM> of the spring bore <NUM> extending inwardly of the first cover <NUM> and an upper portion <NUM> which extends into engagement with the base <NUM> of a piston spring bore <NUM> extending inwardly of the first cover loading surface <NUM> of the lower face <NUM> of the modified seal sleeve <NUM>, generally centered across the surface thereof. Central flow passage <NUM> is in fluid communication with the first bore <NUM> and thus the second bore <NUM> of the first adaptor <NUM> through a first cross passage <NUM> in the body <NUM> extending therebetween. Similarly, the counterbore <NUM> is in communication with the first bore <NUM> and second threaded bore <NUM> of the second adaptor <NUM> through a second cross passage <NUM> in the body <NUM> extending therebetween. Conforming seat ring <NUM> is disposed against, and configured to seal against, annular seat wall <NUM>, and the modified seal sleeve <NUM> is selectively moveable, based on the difference in pressure between the pressures in the first bores <NUM> and second threaded bores <NUM> of the first and second adaptors <NUM>, <NUM> and the spring constant of the spring <NUM>, to either seal against the conforming seat ring <NUM> and thereby prevent fluid communication between the central flow passage <NUM> and the counterbore <NUM> and thus between the first bores <NUM> and second threaded bores <NUM> of the first and second adaptors <NUM>, <NUM>, or to move away from the conforming seat ring <NUM> under the influence of a sufficiently higher pressure in the first bore <NUM> and second threaded bore <NUM> of the first adaptor <NUM> as compared to the pressure in the first bore <NUM> and second threaded bore <NUM> of the second adaptor <NUM> to compress the spring <NUM> and thereby cause the modified seal sleeve <NUM> to move away from the conforming seat ring <NUM>. Thus, in use, when the pressure in the first bore <NUM> of the second adaptor <NUM> is greater than that in the first bore <NUM> of the first adaptor <NUM>, the modified seal sleeve <NUM> seats against an annular region <NUM> of the facing annular surface of the conforming seat ring <NUM>, thereby preventing flow from the first bore <NUM> of the second adaptor <NUM> to the first bore <NUM> of the first adaptor <NUM>, unless this status is physically overridden, or, the pressure in the first bore <NUM> of the first adaptor <NUM> exceeds the pressure in the first bore of the second adaptor <NUM> by a value sufficient to overcome the force of the spring <NUM> tending to push the modified seal sleeve <NUM> seats against an annular region <NUM> of the facing annular surface of the conforming seat ring <NUM>.

A cage <NUM> is disposed in the counterbore <NUM>, and includes a central aperture <NUM> therein extending in the direction between the conforming seat ring <NUM> and the first cover <NUM>. Cage <NUM> is configured to provide a cylindrical guide surface <NUM> surrounding the inner bore thereof, which is configured to allow the modified seal sleeve <NUM> to move linearly toward and away from the conforming seat ring <NUM>, and guide and align this movement. As shown in <FIG>, the modified seal sleeve <NUM> includes a first minor diameter portion <NUM> having a generally right cylindrical seal sleeve outer surface <NUM> extending in the direction between the conforming seat ring <NUM> and the first cover <NUM>, wherein the diameter of the cylindrical seal sleeve outer surface <NUM> of the minor diameter portion <NUM> is <NUM> to <NUM> inches (<NUM> to <NUM>) smaller than the corresponding diameter of the cylindrical guide surface <NUM>. A minor diameter portion seal groove <NUM> extends circumferentially around, and inwardly of, the seal sleeve outer surface <NUM>, and includes therein a pair of seal sleeve back up rings <NUM> and a seal sleeve seal ring <NUM> interposed between the seal sleeve back up rings <NUM>, and contacting both the base of the minor diameter portion seal groove <NUM> and the cylindrical guide surface <NUM> to seal the space between the minor diameter portion seal groove <NUM> and the cylindrical guide surface <NUM> to prevent fluid flow there past or therethrough. Modified seal sleeve <NUM> further includes a seal sleeve major diameter portion <NUM> extending integrally from the first minor diameter portion <NUM> as an integral extension thereof and in the direction of the conforming seat ring <NUM>. Seal sleeve major diameter portion includes an annular extending portion <NUM> extending integrally from the first minor diameter portion <NUM> as an integral extension thereof in the direction of the conforming seat ring <NUM> terminating in an annular seal face <NUM>, which surrounds a central recess <NUM>. The outer surface of the annular extending portion <NUM> includes an outer cylindrical seal sleeve major diameter outer wall <NUM>, and a connecting ledge <NUM> connects the outer cylindrical seal sleeve major diameter outer wall <NUM> and the seal sleeve outer surface <NUM>. The central recess <NUM> includes a central recess surface <NUM>, and a flow balance passage <NUM> opens thereinto and extends through the body of the modified seal sleeve <NUM> to open through the base <NUM> of lower piston spring bore <NUM> of the modified seal sleeve <NUM>.

Cage <NUM> is configured to guide the modified seal sleeve <NUM> to be generally centered along the centerline <NUM> of the cage <NUM> during movement thereof toward and away from conforming seat ring <NUM>, to prevent the modified seal sleeve <NUM> from cocking, or having its longitudinal axis greatly deviate from that of centerline <NUM>, as it moves. Cage <NUM> includes a first outer cage surface <NUM> disposed adjacent to the first cover <NUM> having a diameter on the order of <NUM> to <NUM> inches (<NUM> to <NUM>) less than the corresponding inner circumferential surface <NUM> of the counterbore <NUM>, and a second outer cage surface <NUM> disposed adjacent to the conforming seat ring <NUM> and having a diameter on the order of <NUM> to <NUM> inches (<NUM> to <NUM>) less than the corresponding inner circumferential surface <NUM> of the counterbore <NUM>, a cage lower annular surface <NUM> facing the first cover <NUM>, a cage upper annular surface <NUM> facing, and contacting, the conforming seat ring <NUM>, an annular recess <NUM> extending inwardly of and between the first and second outer cage surfaces <NUM>, <NUM>, and an upper guide surface <NUM> having an inner diameter on the order of <NUM> to <NUM> inches (<NUM> to <NUM>) greater than that of the outer cylindrical seal sleeve major diameter outer wall <NUM>.

Additionally, cage <NUM> includes a circumferential recess <NUM> extending inwardly of the lower annular surface <NUM> and the first outer cage surface <NUM> thereof. Circumferential recess has a lower annular wall <NUM> extending inwardly of the cage <NUM> and facing the first cover <NUM> and terminating at a circumferential pilot wall <NUM> extending therefrom to the lower annular surface <NUM> of the cage <NUM>. A circumferential seal gland <NUM> extends inwardly of the pilot wall <NUM> generally midway between the lower annular wall <NUM> and the lower annular surface <NUM> of the cage <NUM>. A seal ring <NUM>, for example an O-ring, is received in the circumferential seal gland <NUM>, and seals against the base of the circumferential seal gland <NUM> and the inner annular guide wall <NUM> of the first annular boss <NUM> to seal off fluid flow and communication in any gap between the inner annular guide wall <NUM> of the first annular boss <NUM> and the pilot wall <NUM>.

As best shown in <FIG>, <FIG>, conforming seat ring <NUM> has an annular ring shaped body <NUM>, including a first annular face <NUM>, here facing the annular seat wall <NUM> of the valve body <NUM>, an opposed second annular face <NUM> here facing the cage upper annular surface <NUM>, the second annular face <NUM> having a series of the projections <NUM> extending therefrom and which extend outwardly from an inner annular region <NUM> of the second annular face <NUM>. Ring shaped body <NUM> further includes an inner, generally circular, opening <NUM> therethrough having an inner circumferential wall <NUM> terminating at its opposed sides (first and second annular faces <NUM>, <NUM>) at opposed first and second frustoconical faces <NUM>, <NUM> (<FIG>) and an outer circumferential wall <NUM>. Outer circumferential wall includes a circumferential gland <NUM> extending thereinto, within which a conforming seat ring outer seal <NUM> (<FIG>) is positioned to seal between the base of the circumferential gland <NUM> and the inner counterbore wall <NUM> to prevent fluid leakage or fluid communication in any gap between the inner counterbore wall <NUM> and the outer circumferential wall <NUM> of the conforming seat ring <NUM>.

Here, the second annular face <NUM> of the conforming seat ring <NUM> includes the inner annular region <NUM> presenting as a generally flat or planar annular region extending radially outwardly of the intersection thereof with the first frustoconical face <NUM>, an outer annular region <NUM> presenting as a generally flat or planar annular region extending radially inwardly of the outer circumferential wall <NUM>, and an annular intermediate region <NUM>, from which the projections <NUM> project, extending therebetween. Here, inner annular region <NUM> and outer annular region <NUM> are generally coplanar when the conforming seat ring <NUM> is in a free state, i.e., when the conforming seat ring <NUM> is in an unbiased or un-squeezed state prior to the conforming seat ring <NUM> being pressed by the cage <NUM> against annular seat wall113.

The inner annular region <NUM>, outer annular region <NUM> and intermediate annular region <NUM> of the conforming seal sleeve196 are located, and sized, with respect to the cage <NUM> and the modified seal sleeve <NUM>, to ensure that the projections <NUM> contact the cage upper annular surface <NUM>, and the connecting ledge <NUM> of the modified seal sleeve <NUM> can contact only the inner annular region <NUM> of conforming seat ring <NUM>. Thus, as shown in <FIG> the central flow passage <NUM> here is a generally circular in cross-section passage having a diameter D<NUM>, first frustoconical surface <NUM> has a maximum diameter, at the intersection thereof with inner annular region <NUM>, of D<NUM> which is greater than diameter D<NUM>, inner circumferential wall <NUM> has a diameter D<NUM> which is greater than D<NUM> but less than D<NUM>, and the inner annular region <NUM> extends from diameter D<NUM> which is generally equal to diameter D<NUM> to diameter D<NUM>, at which diameter the intermediate annular region <NUM> begins. Connecting ledge <NUM> has an inner diameter D<NUM> greater than both diameter D<NUM> and diameter D<NUM> and an outer diameter D<NUM> greater than inner diameter D<NUM> and less than diameter D<NUM>, all diameters D1 to D<NUM> are centered on centerline C of the conforming seat ring <NUM>. As a result, when modified seal sleeve <NUM> is biased against conforming seat ring <NUM>, it will inherently contact the inner annular region <NUM> thereof, and thus not come into contact with the projections <NUM> of the intermediate region <NUM>. Additionally, the inner diameter of the upper guide surface <NUM> of the cage <NUM> is slightly larger than the outer diameter D<NUM> of the connecting ledge <NUM>, and it extends outwardly therefrom to approximately the same diameter as the outer diameter of the conforming seat ring <NUM>, thereby ensuring that at least a portion of the cage upper annular surface <NUM> faces the projections <NUM> of the intermediate annular region <NUM> of the conforming seat ring <NUM>.

Here, the projections <NUM> extend as integral extensions from the conforming seat ring <NUM>, and here include four annular projections <NUM>-<NUM>, each of the four annular projections <NUM>-<NUM> having an annular base <NUM> and four arcuate projections <NUM> extending integrally therefrom in the direction further away from the annular surfaces <NUM>, <NUM>. Thus the first annular projection <NUM> extends circumferentially at a first projection circumference from the centerline C, and it includes an annular base <NUM> and four arcuate projections <NUM> extending therefrom and equally spaced about the first circumference from the center C. The second annular projection <NUM> extends circumferentially about a second projection circumference about the centerline C greater than the first projection circumference, and it also includes an annular base <NUM> and four arcuate projections <NUM> equally spaced from one another along the second projection circumference from the center C. The third annular projection <NUM> likewise includes an annular base <NUM> and four arcuate projections <NUM> extending therefrom and equally spaced from one another along a third projection circumference about the centerline C greater than the second projection circumference, and the fourth annular projection <NUM> includes and annular base <NUM> and four arcuate projections <NUM> extending therefrom and equally spaced from one another along a fourth projection circumference about the centerline C greater than the third projection circumference.

Between each of the arcuate projections <NUM> (here four) at each of the first to fourth projection diameters is a relief gap <NUM>, and in the aspect of the conforming seat ring <NUM> of <FIG>, these gaps are radially aligned with one another along a radius extending from the centerline C of the conforming seat ring <NUM>. Here, for reference, the first through fourth projection circumferences may be considered to be at the radial center of each of the first through fourth annular projections <NUM>-<NUM>, respectively. Each of the first to fourth annular projections <NUM> to <NUM> has, in a free state, where the projections <NUM> are not compressed or squeezed inwardly toward the main bulk of the body of the conforming seat ring <NUM>, a thickness t<NUM> as shown in <FIG>, and in a maximum compressed state of the projections they have a thickness t<NUM> as shown in <FIG>. Additionally, as shown in <FIG>, the conforming seat ring <NUM>, not including the thickness of the projections <NUM> (<NUM> to <NUM>), has a thickness t<NUM> between the inner and outer annular surfaces <NUM>, <NUM> and the first annular face <NUM> thereof, and this thickness t<NUM> remains relatively constant between the free, i.e., uncompressed or un-squeezed state of the conforming seat ring <NUM> before it is installed in the non-gapped check valve <NUM>, and the thickness of t<NUM> valve-installed state of the conforming seat ring <NUM>. Each of the arcuate projections <NUM> (<NUM> to <NUM>) in this aspect of the conforming seat ring <NUM> has a saw tooth or triangular profile in section (across a radius of the modified seat ring <NUM> centered at centerline C), with opposed sidewalls <NUM>, <NUM> extending along opposed radial sides of each of the first through fourth annular projections <NUM> (<NUM>-<NUM>) and meeting at a peak <NUM>, the length of each peak <NUM> defining an arc extending along the aforementioned one of the first through fourth projection circumferences. Although the projections <NUM> (<NUM>-<NUM>) here are shown as four annular projections <NUM> (<NUM>-<NUM>), each having four arcuate projections <NUM> equally circumferentially spaced along the circumference of the respective firth through fourth projection circumference which they extend, with radially aligned relief gaps <NUM> therebetween, other numbers of annular projections <NUM>, other relief gap <NUM> arrangements, for example relief gaps <NUM> along different ones of the first through fourth projection circumferences that are not radially aligned across the projections <NUM>, other arcuate projection <NUM> profiles such as semi-circular or truncated cone in section, or other ellipsoid or geometric shapes of the arcuate projections <NUM> are specifically contemplated herein. Furthermore, the relief gas <NUM> may have different circumferential lengths in different ones of the projections <NUM> (<NUM> - <NUM>). Additionally, although the projections <NUM> (<NUM>-<NUM>) are centered about the centerline C of the circular, in plan view, conforming seat ring <NUM>, they may have a different center offset from the location of the center C of the circular, in plan view, conforming seat ring <NUM>, or each of the projections <NUM> (<NUM>-<NUM>) may extend around different centers at least one of which may be the same, or different than, the centerline C of the circular, in plan view, conforming seat ring <NUM>. Additionally, the projections <NUM> (<NUM> to <NUM>) here are shown as following a circular circumferential path, although they may trace other paths along the cage <NUM> facing side of the conforming seat ring <NUM>.

As discussed herein with respect to <FIG>, where the seat ring <NUM> has a generally planar surface over its radius and circumference facing the cage <NUM>, the dimensional tolerance stack of the cage <NUM>, the counterbore of the valve body, and the seal ring are such that a purposefully created tolerance stack gap 18a is required to ensure that at certain tolerance limits of these elements, there remains no free space within the valve body between the cage <NUM> and the seat ring <NUM>. Here, the conforming seat ring <NUM>, which is manufactured of a relatively stiff, but deformable material which does not break down in the presence of the hydraulic fluid in the valve, for example a material such as PEEK or Delrin® 511P, includes the four annular projections <NUM>-<NUM> that can be compressed, despite having the same material construct as the adjacent portions of the main body of the conforming seat ring <NUM>, and they thus serve to ensure that the cage <NUM> loads against the conforming seat ring <NUM> such that the first annular face <NUM> of the conforming seat ring <NUM> is pressed against and contacts the second annular face <NUM> of the body <NUM> when the annular cover wall <NUM> of the body <NUM> contacts the circumferential limit wall <NUM> of the first cover <NUM>, over the entire tolerance range of the dimensions of the conforming seat ring <NUM>, first cover <NUM> and cage <NUM>. As a result, the tolerance stack gap 18a, and the resultant corrosion and failure issues attendant with the valve of <FIG> and <FIG>, is eliminated. This is provided by sizing the difference between the free state thickness t<NUM> and the maximum compressed thickness t<NUM> of the projections <NUM> (<NUM>-<NUM>) to be greater than, or equal to, the maximum difference in the tolerance stack of the conforming seat ring <NUM>, first cover <NUM> and cage <NUM>. As a result, when the non-gapped check valve <NUM> is properly assembled, the annular cover wall <NUM> of the body <NUM> can, and always will, contact the circumferential limit wall <NUM> of the first cover <NUM> thereby preventing exposure of these surfaces to an ambient corrosive environment and the eventual stress corrosion cracking experienced in the structure of <FIG> and <FIG>. Additionally, the total height of the conforming seat ring <NUM> of H<NUM>, including the free non compressed height t<NUM> of the projections, is sized such that the lower cover wall <NUM> of the body <NUM> is spaced from the surface of the second cover main body <NUM> extending around the cover boss <NUM> over the entire range of dimensional tolerance of the components of the valve when the cage <NUM> biases the conforming seat ring <NUM> in contact therewith against the annular seat wall113 before the first cover <NUM> is secured against the wall <NUM>, and, at the maximum compressed height H2 of the conforming seat ring <NUM> after the lower cover wall <NUM> of the body <NUM> is in contact with the surface of the second cover main body <NUM> extending around the cover boss <NUM> the cage <NUM> is biased against the conforming seat ring <NUM> and the conforming seat ring <NUM> is biased against the annular seat wall113 so that the conforming seat ring <NUM> is not free to move within the non-gapped check valve <NUM>.

By way of example, assuming the counterbore <NUM> has a depth from the lower cover wall <NUM> to the annular seat wall113 of a depth of <NUM> inches (<NUM>), with a tolerance of +/-(plus or minus) <NUM> inches (<NUM>), the cage <NUM> has a height from the cage lower annular surface <NUM> facing the first cover <NUM> to the cage upper annular surface facing of <NUM> inches (<NUM>) with a tolerance of +/- <NUM> inches (<NUM>), the distance between the first cover loading surface <NUM> and the annular valve inwardly facing surface <NUM> of the cover has a dimension of <NUM> inches (<NUM>) with a tolerance of +/- <NUM> inches (<NUM>), and the conforming seat ring <NUM> thickness, including the projections, is t<NUM> + t<NUM> of <NUM> inches (<NUM>), with a tolerance of +/-<NUM> inches (<NUM>). In this case, the maximum stack distance of the dimensions is the sum of the maximum tolerance dimension of the cage <NUM> of <NUM> + <NUM> inches (<NUM> + <NUM>), the maximum tolerance dimension of the height of the inwardly facing surface <NUM> of <NUM> + <NUM> inches (<NUM> + <NUM>), and the maximum tolerance dimension of the conforming seat ring <NUM> thickness (t<NUM> + t<NUM>), <NUM> + <NUM> inches (<NUM> + <NUM>), which equals <NUM> inches (<NUM>). The minimum stack distance of the dimensions H<NUM>, H<NUM> and t<NUM> is the sum of the corresponding minimum tolerance dimensions of the cage <NUM> of <NUM> - <NUM> inches (<NUM> - <NUM>), the minimum tolerance dimension of the height of the inwardly facing surface <NUM> of <NUM> - <NUM> inches (<NUM> - <NUM>), and the minimum tolerance dimension of the thickness of the conforming seat ring <NUM> (t<NUM> + t<NUM>) of <NUM> - <NUM> inches (<NUM> - <NUM>) tolerance, which equals <NUM> inches (<NUM>). Thus, the maximum depth of the counterbore <NUM> must be less than, or equal to, the minimum stack distance of here <NUM> inches (<NUM>). To ensure that the conforming seat ring <NUM> is firmly secured between the cage <NUM> and the annular seat wall <NUM> before the threaded fasteners <NUM> extending through openings in the first cover <NUM> are tightened into the corresponding threaded apertures provided therefor (not shown) extending inwardly of the lower cover wall <NUM>, the maximum depth of the counterbore is slightly less than the minimum stack distance to leave an indicator gap between the lower cover wall <NUM> and the circumferential limit wall <NUM> of the first cover before assembly as a visual indicator to the valve assembler that the cage <NUM> is contacting the conforming seat ring <NUM> and the conforming seat ring <NUM> is contacting the annular seat wall113 before the threaded fasteners <NUM> extending through openings in the first cover <NUM> are tightened into the corresponding threaded apertures provided therefor (not shown) extending inwardly of the lower cover wall <NUM>. The projections <NUM> are compressible in the direction of the second annular surface of the conforming seat ring <NUM>, for example on the order of <NUM> to <NUM> inches (<NUM> to <NUM>) of compression. For example, the maximum depth of the counterbore is, for the minimum stack distance of <NUM> inches (<NUM>), for example <NUM> inches (<NUM>).

Assuming the tolerance of the depth of the counterbore <NUM> is +/- <NUM> inches (<NUM>), the minimum depth of the counterbore <NUM> is <NUM> inches (<NUM>). Thus, where the maximum stack distance of is present, in this example <NUM> inches (<NUM>), the projections <NUM> must be capable of compressing (being compressed) by an amount equal to the difference between the counterbore <NUM> minimum depth of <NUM> inches (<NUM>) and the maximum stack distance of <NUM> inches (<NUM>).

Relief gaps <NUM> are provided in the projections <NUM> to allow air or other fluid to escape from between the arcuate projections <NUM> (<NUM>-<NUM>) on adjacent ones of the first to fourth projections <NUM> - <NUM> as the threaded fasteners <NUM> extending through openings in the first cover <NUM> are tightened into the corresponding threaded apertures provided therefor (not shown) extending inwardly of the lower cover wall <NUM> and the volume between the adjacent ones of the projections and the facing surface of the cage <NUM> is thereby reduced.

Referring again to <FIG>, non-gapped check valve <NUM> here also includes an override system, here including a pilot piston <NUM> reciprocally moveable in the piston bore <NUM> extending inwardly of the upper cover wall <NUM>, and including an override rod <NUM> extending from an annular piston surface <NUM> facing inwardly of the override piston bore <NUM>, through the rod alignment passage <NUM> to contact the central recess surface <NUM> of the modified seal sleeve <NUM> at the rod end <NUM>. The actuator bore <NUM> through the third adaptor <NUM> communicates with the back side <NUM> of the pilot piston <NUM> within the piston bore <NUM>.

In operation, when the non-gapped check valve <NUM> is functioning as a pressure relief valve, when the pressure in the first cross passage <NUM> in the body <NUM> is at a monitored line pressure below the cracking pressure and the first adaptor <NUM> is connected to a monitored line (not shown), the force of the spring <NUM> and the pressure force of the fluid pressure bearing against the lower face <NUM> of the modified seal sleeve <NUM>, as well as the force of the fluid pressure bearing against the annular connecting ledge <NUM> together exceed the pressure force exerted by the pressure in the first cross passage <NUM> communicating with the central recess surface <NUM> of the modified seal sleeve <NUM> communicated thereto through the central flow passage <NUM> and the opening <NUM> in the conforming seat ring <NUM>, the modified seal sleeve <NUM> will maintain the position thereof shown in <FIG>, wherein the connecting ledge <NUM> thereof contacts the conforming seat ring <NUM> on the inner annular region <NUM> thereof. As shown in <FIG>, connecting ledge <NUM> is a generally frustoconical surface, having a generally flat surface <NUM> extending at an angle α of greater than <NUM> and less than <NUM> degrees, from the adjacent inner annular surface <NUM> of the annular extending portion <NUM> of the modified seal sleeve <NUM>, resulting in a circumferential edge <NUM> which initially engages the inner annular region <NUM> of the conforming seat ring <NUM> in line contact, and allows the generally flat surface <NUM> adjacent to the circumferential edge <NUM> to push inwardly of the inner annular region <NUM> of the conforming seat ring <NUM> to seal off fluid communication between the first cross passage <NUM> fluidly connected to the monitored fluid line when the second cross passage <NUM> is exposed different pressure ambient or different pressure line, for example to the ambient pressure conditions the valve and the first bore <NUM> in the second adaptor <NUM> is functioning as a vent. This is possible because during steady state pressure conditions in the first cross passage <NUM>, the pressure against the lower face <NUM> of the modified seal sleeve <NUM> is equal to the pressure in the first cross passage <NUM> as communicated through the flow balance passage <NUM>.

If the pressure in the first cross passage <NUM> in the body <NUM> changes to a monitored line pressure above the regulated pressure, the force of the spring <NUM> and the pressure force of the fluid pressure bearing against the lower face <NUM> of the modified seal sleeve <NUM>, as well as the force of the pressure bearing against the annular connecting ledge <NUM> together will not exceed the pressure force exerted by the pressure in the first cross passage <NUM> communicating with the central recess surface <NUM> of the modified seal sleeve <NUM> communicated thereto through the central flow passage <NUM> and the opening <NUM> in the conforming seat ring <NUM>, and the modified seal sleeve <NUM> will move in the direction of the position thereof shown in <FIG> and an annular relief gap <NUM> allows fluid communication between the first cross passage <NUM> and the second cross passage <NUM> exposed to a lower pressure ambient or low pressure line, allowing the overpressure condition in the monitored fluid line to vent. Once the pressure is reduced by a sufficient amount, such that the pressure in in the first cross passage <NUM> communicating with the central recess surface <NUM> of the modified seal sleeve <NUM> communicated thereto through the central flow passage <NUM> and the opening <NUM> in the conforming seat ring <NUM> is insufficient to overcome the force of the spring <NUM> and the pressure force of the fluid pressure bearing against the lower face <NUM> of the modified seal sleeve <NUM>, as well as the force of the pressure bearing against the annular connecting ledge <NUM> together, the modified seal sleeve <NUM> will move back to the position thereof in <FIG>.

Modified seal sleeve <NUM> here, in normal operating conditions, i.e., where an overpressure condition is not present in first cross passage <NUM>, is in a pressure balanced state, as the flow balance passage <NUM> allows fluid communication, and equal pressure, on both the seal sleeve lower surface <NUM> and central recess surface <NUM>. However, when a rapid spike in pressure occurs in the monitored fluid line, the flow balance passage <NUM> has an insufficient cross section to allow this pressure to rapidly communicate to the seal sleeve lower surface <NUM>, and the modified seal sleeve <NUM> will move to vent the overpressure condition.

In the event the valve operation needs to be overridden, a force sufficient to push the pilot piston <NUM> in the direction of the modified seal sleeve <NUM> causes the rod end <NUM> to push the modified seal sleeve <NUM> away from the conforming seat ring <NUM> and thereby form the annular relief gap <NUM> (<FIG>) to allow pressure and fluid communication between the valve. This can be accomplished by an adequate fluid pressure supplied through the actuator bore to move the pilot piston <NUM> toward the modified seal sleeve <NUM>, or by a mechanical pin extending from an actuator, such as a solenoid, configured to contact the back side <NUM> of the pilot piston <NUM> and thereby move the pilot piston <NUM> toward the modified seal sleeve <NUM>.

Claim 1:
A valve, comprising:
a valve body (<NUM>) including a first fluid port (<NUM>) opening from the valve body, a second fluid port (<NUM>) opening from the valve body, and an interior passage (<NUM>) fluidly connecting the first fluid port and the second fluid port;
a bore (<NUM>) extending inwardly of a first wall (<NUM>) of the valve body and having an annular first seat securement surface (<NUM>) extending around the interior passage intermediate of the first fluid port and the second fluid port, the second fluid port fluidly connected to the bore;
a cage (<NUM>) disposed in the bore, the cage having an annular second seat securement surface (<NUM>) and an opposed first annular surface (<NUM>), the annular second seat securement surface facing the annular first seat securement surface;
a cover (<NUM>) extending over the first wall of the valve body and the opening of the bore thereof, the cover including a cage engagement surface (<NUM>) contacting the first annular surface; and
an annular seat (<NUM>) having a main body having an opening therethrough and a first seat surface (<NUM>) facing and contacting the annular first seat securement surface of the valve body and a second seat surface (<NUM>), facing away from the first seat surface, characterised in that the second seat surface comprises a first annular region having a first elevation and a second annular region different than the first annular region, and the second annular region comprises at least one projection (<NUM>) projecting from the annular seat to an elevation greater than the first elevation and contacting the annular second seat securement surface,
wherein the at least one projection (<NUM>) extends circumferentially around the opening (<NUM>) in the annular seat (<NUM>),
wherein the at least one projection (<NUM>) includes at least one secondary arcuate projection (<NUM>) projecting therefrom in a direction away from the first annular surface,
wherein at least one secondary arcuate projection (<NUM>) comprises at least two arcuate projections (<NUM>), each arcuate projection (<NUM>) spaced from another of the arcuate projections with a gap (<NUM>) therebetween.