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[ EN ]

Title: Shock Absorbing Means For Flow Control Devices

This application is a continuation-in-part of application serial no. 502,047 fil March 30, 1990 and entitled "Shock Absorbing Sealing Means For Flow Contr Devices".
This invention relates to shock absorbing means for flow control devices, a more particularly to shock absorbing means for reciprocable flow control membe of flow control devices such as valves.
Heretofore, such as shown in U.S. Patent No.3,433,250 dated March 18, 196 safety relief valves have been provided with means to absorb at least some of t impact forces upon reseating of a reciprocable valve member. However, up reseating of the valve member, substantial radial deflection may occur after initial li contact of the valve sealing face with the fixed seat ring. Such radial deflection undesirable and oftentimes results in undue wear and possible damage to t contacting faces.
Also, shock absorbing sealing means for flow control devices such as valve have utilized elastomeric members for absorbing shock. For example, U.S. Pate No. 4,858,642 dated August 22, 1989 shows a pressure operated relief valve i which an elastomeric member is positioned between a valve disc and a disc hold to absorb shock forces upon reseating of the valve member resulting from reduction in pressure after actuation of the valve member. Elastomeric members ar subject to deterioration at high temperatures, such as temperatures over around 50 F for example.
Other impact type valves have utilized fluid metering for absorbing shock forc upon impact of the valve member against a valve seat or for reducing the speed movement of the valve member prior to impact thereby to minimize impact force Such fluid metering arrangements are costly, relatively complex, and do not usu absorb all of the impact forces.
Prior application serial no. 502,047 filed March 30, 1990 shows a sh absorbing sealing means for reciprocable flow control members of flow cont devices such as valves. The specific embodiments illustrated in application serial 502,047 are directed to such shock absorbing means in which the shock absorbi member is mounted on and carried by the reciprocable valve member with t shock absorbing member flexing or deflecting upon contact of the valve mem with a fixed seat ring thereby to absorb the impact forces.
The present invention provides a shock absorbing sealing means reciprocable flow control members, such as valves, in which the shock absorbi member is mounted on the annular seat or nozzle against which the reciproca flow control member seats. The reciprocable flow control member norma comprises a reciprocable valve member in a pressure relief valve, for example, a upon unseating of the valve member at a predetermined high fluid pressure, t valve member oftentimes reseats with an impact force exerted against the seat. minimize wear, damage, leakage, and the like to impacting members, it is desira that the impact forces or energy generated by impact be dissipated or absorb with minimal radial deflection between contacting faces of the seat ring a reciprocable valve member. The seat assembly of the present invention defines nozzle or seat ring extending about a flow passage and a flexible connecti member extends outwardly from the seat ring to means anchoring the seat ring. T flexible connecting member permits by flexure thereof upon impact of the val member against the seat ring a cushioned longitudinal movement of the reciprocabl valve member after contact with the metal seat ring thereby to absorb impact force Bending movements are exerted at the hinging or joining of opposite ends of th flexible connecting member between the anchoring means and the metal seal rin of the seat assembly. Thus, the size of the flexible connecting member and the se ring may be determined depending on the specifications and operating parameter for the valve structure.

It is an object of this invention to provide shock absorbing means for a hi temperature flow control device having a reciprocable flow control member mova along a longitudinal axis and seating against a flexible seat ring.
It is a further object of this invention to provide shock absorbing means such a flow control device including a seat ring defining a nozzle extending ab a flow passage and connected to a generally radially extending flexible connecti which flexes upon contact of the reciprocable flow control member for absorbi impact forces.
An additional object of this invention is to provide shock absorbing means a safety relief valve seated in closed position on a nozzle about the flow passa with a generally radially extending flexible member connected to the nozzle absorbing impact forces upon impact of the relief valve member against the nozz

Other objects, features, and advantages of the invention will be in part and part pointed out hereinafter.
Figure 1 is a schematic view of a safety relief system illustrating a main rel valve and associated pilot valve positioned on a pressure vessel for utilizing t present invention;
Figure 2 is an enlarged cross section of the pilot operated pressure relief val shown in Figure 1 with the reciprocable valve member shown in an open positi to permit fluid flow through the valve for relieving fluid pressure and adapted reseating against the nozzle ring about the flow passage;
Figure 3 is an enlarged fragment of Figure 2 illustrating particularly the sizi of the members forming the shock absorbing sealing means of the present inventi and showing in broken lines the movement of the nozzle ring upon flexing of t flexible member connected to the nozzle ring after impact of the valve memb against the nozzle ring;
Figure 4 is a cross section of another embodiment of the present inventi showing a non-pilot operated pressure relief valve in closed position seated on t flexible nozzle assembly of the present invention; and
Figure 5 is an enlarged fragment of Figure 4 showing the shock absorbi sealing means of the present invention.

Referring now to the drawings for a better understanding of this invention a more particularly to Figure 1 in which a safety relief system is shown illustrating use of the present invention, a pressure vessel or tank is shown generally at having an outlet 12 extending therefrom. A main relief valve is indicated generally

14 and has a main body 16 with a cap or cover 18 secured thereto. A pilot val generally indicated at 20 is mounted on relief valve 14. An inlet line 22 extends fro main valve 14 to pilot valve 20 and an outlet line 24 extends from pilot valve 20 the downstream side of body 16. A control fluid line 26 extends from pilot valve to a dome or dome chamber 28 of main relief valve 14. The pressure release syste illustrated is particularly adapted for high temperature over around 350 F and m be utilized with steam, liquid, or vapor with various types of pressure vessels or flu flow lines extending to main relief valve 14. An exhaust 29 provides a vent atmosphere for pilot valve 20.
Valve body 16 defines an inlet flow passage at 30 and an outlet flow passa at 32. A fluid operated reciprocable valve member is generally indicated at 34 havi dome chamber 28 therein and mounted for reciprocable movement between op and closed positions. Valve member 34 moves to an open position as shown i Figure 2 resulting from a predetermined high fluid pressure being reached i pressure vessel 10 and inlet passage 30 sensed by pilot line 22. Upon a reductio in fluid pressure in pressure vessel 10 and inlet passage 30 as sensed by pilot valv 20, valve member 34 reseats on nozzle assembly 38. Oftentimes, even wit dampening of the movement of valve member 34, and particularly upon a relativ fast reduction in fluid pressure in inlet passage 30 after opening, valve member 3 moves rapidly to closed seated position to exert impact forces against nozzl assembly 38. Impact forces may cause abnormal wear or damage which coul result in fluid leakage in the closed position of valve member 34. An annular se face 36 is provided on the end of reciprocable valve member 34 and has a widt indicated at T1.
A nozzle assembly or seat ring assembly generally indicated at 38 forms a important part of this invention and is mounted about flow passage 32. Nozzl assembly 38 includes an inner nozzle or seat ring indicated at 40, an outer securin or anchoring ring indicated at 42, and a flexible connecting member 44 extendin in a generally radial direction between seat ring 40 and anchor ring 42. For securi or mounting nozzle assembly 38 a sleeve generally indicated at 45 has an inn periphery 46 defining flow passage 32 and a threaded outer periphery 48. The inn annular end 50 of sleeve 45 has an annular recess defining a shoulder 52 and outer peripheral surface 54. Body 16 is internally threaded at 55 and has an inn flange or overhanging lip 56 spaced in opposed relation to annular end 50 to defi a receiving groove therebetween. Anchor ring 42 of nozzle assembly 38 h opposed ends 58 and sealing gaskets 60 which are gripped between lip 56 and e 50 upon threading of sleeve 45 within body 16 tightly against anchor ring 42.
Nozzle or seat ring 40 has an inner peripheral surface 62 and an out peripheral surface 64 which are spaced radially from each other. The center gravity of seat ring 40 is shown at 65. The upper annular end 66 of seat ring defines a seating face having a width W2 for contacting and sealing against face of valve member 34 which has a width T1. The lower annular end 68 of seat ring is received within the inner recess of sleeve 45 and may contact shoulder 52 restrict axial movement of ring 40 and overstressing of seat assembly 38 up impact loads from valve member 34 as will be explained further below.
Flexible connecting member 44 extends in a generally radial direction betwe seat ring 40 and anchor ring 42. Connecting member 44 is hinged to the inn peripheral surface of outer ring 42 about point 72 and hinged to the outer periphe surface 64 of seat ring 40 at point 74. Flexible connecting member 44 flexes aft initial contact of sealing face 36 on valve member 34 with face 66 of seat ring 40 a is constructed and arranged for a predetermined flexure relative to anchor ring for absorbing impact forces with minimal radial and angular deflections of seali face 66 on seat ring 40 and for providing alignment between faces 36 and 66.

As shown in Figure 3, seat ring 40 of nozzle assembly 38 moves an axi distance D after contact of seal face 36 with seat face 66. Distance D is at lea greater than around .002 inch and may be as high as around .030 inch or great depending primarily on such factors as the size of valve member 34 and vario operating parameters. Planar rear face 68 of seat ring 40 is normally spaced fro shoulder 52 and shoulder 52 acts as a stop when contacted by rear face 68 to li the maximum travel S of seat ring 40 past the elastic limit of connecting member after seat face 66 is contacted by seal face 36. The longitudinal axis of flexib connecting member 44 is shown at 76. The thickness of connecting member 4 indicated at T.
Seat ring 40 has a maximum thickness indicated at T2, and a width indicat at W. The center of gravity of seat ring 40 indicated at 65 is offset an axial dista D1 from the centerline of connecting member 44 at hinge point 72 in a directi toward or longitudinally inwardly of seat face 66. Such an offset has been fou desirable in order to minimize any angular or radial deflection of seat face 66 up flexing of connecting member 44 resulting from movement of seat ring 40 after s face 36 contacts seat face 66. An offset distance D1 of at least around .050 inch believed desirable in order to minimize the deflection of seat face 66 to insignificant amount.
Further, in order for the flexing of connecting member 44 to maintain alignm of seat face 66 against seal face 36 upon impacting of valve member 34 agai seat ring 40, it is desirable that the maximum thickness T1 of seat ring 40 be at le around twice the thickness T of connecting member 44. Further, it is desirable th the width W of seat ring 40 be at least around three times the thickness T connecting member 44. Additionally, in order to minimize the angular and rad deflections of face 66 upon flexure of connecting member 44, the longitudinal a

76 of connecting member 44 slopes toward the center of gravity 65 from hinge poi 72 at the inner peripheral surface of outer ring 42 at a positive slope angle sho at angle A in Figure 3. It is believed that angle A should be between around one-h degree and ten degrees in order to obtain optimum results. It is noted that t center of gravity 65 is positioned between valve member 34 and connecting memb

44 in the embodiment of Figures 1-3. It is to be understood that in the eve connecting member 44 is positioned between valve member 34 and the center gravity, connecting member 44 will slope in an opposite direction at a negative slo angle.
Planar face 36 is of a width T1 greater than the width W2 of planar face 66 f the most effective sealing action and with minimal radial and angular deflection occurring after contact. Such an arrangement accommodates any lack concentricity between faces 36 and 66. Seal face 36 is formed of a harder fac material than is seat face 66.

It is apparent from the above that the design of the flexible connecting memb 44 between seat ring 40 and anchor ring 42 may be predetermined in order to ha sufficient flexure to absorb the impact forces while minimizing the deflection of se face 66. While anchor ring 42, connecting member 44, and seat ring 40 are sho as an integral construction in seat assembly 38, it is to be understood th connecting member 44 may be formed of a separate member, if desired, such a Belleville washer, for example.
While metal is a preferred material from which the present invention is forme it is to be understood that other hard material resistant to high temperature, su as certain types of ceramic and composite materials, may be utilized in satisfactory manner. The term "hard" as used in the specification and claims here is interpreted as being "non-elastomeric".
Referring now to Figures 4 and 5, another embodiment of the present inventi is illustrated for a pressure relief valve indicated at 14A which is not pilot operate Pressure relief valve 14A has a valve body 16A including an inlet flow passage 3 and an outlet flow passage 32A. A reciprocable valve member 34A has an annul seal face 36A and is urged into seating engagement by spring 37A.
Improved nozzle assembly 38A has an upper annular seat face 66A engagi seal face 36A on valve member 34A. Nozzle assembly 38A includes an inner se ring 40A, an outer anchor ring 42A, and a flexible connecting member 4 extending in a generally radial direction between the outer periphery 64A of seat ri 40A and the inner periphery of anchor ring 42A. Upon a predetermined high flu pressure being reached in inlet fluid passage 30A, valve member 34A and seal fa 36A are forced outwardly against the bias of spring 37A to permit fluid flow throu fluid passage 32A. Upon a reduction in fluid pressure in inlet 30A, valve memb 34A under the bias of spring 37A moves nozzle assembly 38A to a reseated positi on seat face 60A of seat ring 40A on nozzle assembly 38A.
Flexible connecting member or web 44A functions in the same manner as t embodiment of Figures 1-3 and is generally identical to the embodiment of Figur 1-3. The longitudinal axis 76A of connecting member 44A has a positive slo shown at angle A between hinge points 72A and 74A. Angle A is generally equal angle A in the embodiment of Figures 1-3 and slopes downwardly from seat ri 40A toward anchor ring 42A as in the embodiment of Figures 1-3. Additionally, order to minimize deflection of face 42A after contact against face 20A, the cen of gravity 65A of seat member 40A is positioned forwardly of hinge point 72A tow face 66A as shown at D1. Distance D1 is generally identical to the distance D1 in t embodiment shown in Figures 1-3 thereby to minimize the deflection of face 6 resulting from the flexing of connecting member 44A. Seat ring 40A moves distance D as in the embodiment of Figures 1-3 and rear face 68A of seat ring 4 engages shoulder 52A in abutting contact to limit the movement of seat ring 4 past the elastic limit of connecting member 44A.
While the present invention has been illustrated for utilization with pressure reli valves, it is to be understood that this invention could be utilized with other types fluid flow control devices, such as pumps, check valves, and the like where reciprocable flow control member is provided for seating and reseating against annular seat ring. Thus, it is apparent that modifications and adaptations of t preferred embodiments will occur to those skilled in the art. However, it is to expressly understood that such modifications and adaptations are within the spi and scope of the present invention as set forth in the following claims.