GB2056623A - Clapper retainer for a swing check valve - Google Patents

Abstract

A check valve (10) comprising a casing (20) having a fluid-inlet port (28) and a fluid outlet port (30), and having a valve chamber (26) defined within the casing (20), a pin hanger recess defined by a pin hanger (48), a valve clapper (58) having a clapper pin (68) and being supported within the valve chamber (26) for movement between a seated position and an open position by having the clapper pin (68) positioned in the pin hanger recess, and a resilient clapper retainer split ring (82) positioned within a retainer groove provided in the casing interior, the split ring (82) cooperating with the pin hanger recess to confine the clapper pin (68) in the pin hanger recess. <IMAGE>

Description

SPECIFICATION Clapper retainer for a swing check valve This invention relates to swing-type check valves and, in particular, to a clapper retainer for a swingtype check valve.

The servicing of hydrocarbon producing wells requires the utilization of fluids having relatively high velocities in the order of 40 to 60 feet per second. Typically, swing-type check valves are provided to assist in the control of these relatively high velocity fluids.

Conventionally, a swing-type clapper check valve has a flap or clapper forming the valve member, the clapper having an arm connected thereto. The clapper arm is provided with a clapper pin boss, through which extends a clapper pin in a direction substantially perpendicular to the arm. The ends of the pin may typically be provided with bushings. A pin hanger is formed in the valve casing and has a recess therein formed on the interior of the casing.

The bushings on the ends of the pin are received within the recess in the hanger to support the clapper in a dampening relationship within the casing. The clapper is thus pivotally movable with respect to the axis of the pin and swings on the bearing surfaces provided by the bushings within the recess into and out of the flow path defined between the fluid inlet and fluid outlet in order to interdict or permit the flow of fluid through the valve.

It has been observed when swing-type clapper check valves are utilized to assist in controlling the relatively high pressure and high velocity fluids used in well servicing that the clapper pin has a tendency to unseat from the grasping relationship with the hanger. It is believed that this occurrence results from turbulence and eddies generated from the passage of the high velocity fluid through the valve.

The fluid flow and the eddies therefrom impart a fluttering movement to the clapper which is believed to unseat the clapper pin from the support provided by the hanger.

A solution utilized by the prior art to correct this perceived disadvantage is to fasten plates on the boss in order to restrain the ends of the clapper pin.

The plates are typically held in place by screws threaded into the top of the boss. However, most valve structures in the area of the clapper boss do not exhibit sufficient surface in which the fastening holes for the retainer plates may be drilled and tapped. Further, the quality of the clapper casting and alignment within the valve chamber makes positioning of the retainer plates difficult.

It is well-known in the swing-type clapper check valve art to utilize resilient biasing elements in order to maintain valve clappers in the closed position.

Believed exemplary of this practice are the devices shown in United States Patent 387,802 and United States Patent 1,427,148. Another device, such as that exhibited in United States Patent 2,814,308 utilizes a pivotally mounted valve disc having flaps which are biased into contact with reservoir-defining walls in order to maintain the flaps closed about a fluid port.

United States Patent 3,955,592 also appears to disclose a check valve with a sectional valve body adapted for interposition in a fluid flow line, the valve hanging a pivotallymounted clapper movable toward and awayfrom a valve seat. This valve appears to have a hanger provided inthe valve body and includes a biasing element for urging the clapper toward a normally closed position.

The check valve disclosed in United States Patent 3,933,173 appears to exhibit a check valve of the swing-type that utilizes valve supporters received within recesses provided in the valve casing. The supporters appears to be substantially circular members. In some portions of the last-reference patent the valve supporters appear insertable into a clapper-retaining relationship within the casing in a direction substantially parallel to the direction of fluid flow through the valve.

According to the present invention a check valve which has a casing provided with a fluid inlet port and a fluid outlet port, and forming a valve chamber; and a valve clapper supported within the valve chamber, for pivotal movement between a seated position and an open position, by means of a clapper pin located in a pin hanger recess formed in the casing also, has a resilient clapper retainer disposed in a retainer recess formed in the valve chamber, to confine the clapper pin in the pin hanger recess.

The retainer recess may conventionaly be in the form of an elongate annular groove disposed in a plane, substantially parallel to the fluid flow path through the valve between the inlet port and outlet path; The clapper retainer may be in the form of a resiliently deformable ring-like element, the ring-like element being resiliently deformable to permit withdrawal from and insertion into the retainer recess.

Preferably, the clapper retainer is in the form of a split ring having first and second ends, with the first and second ends cooperating with the hanger recess to confine the clapper pin in the hanger recess.

The first and second ends may be bent to define graspable hooks to be grasped for resiliently deforming the split ring to reduce its peripheral dimension for insertion or withdrawal thereof from the retainer recess.

The invention also includes a method of locating a hanger pin of a valve clapper in a pin hanger recess defined by a pin hanger within a check valve casing.

which method comprises removably disposing a resilient clapper retainer in a groove provided in the casing interior such that the clapper retainer extends over the pin hanger recess to confine the hanger pin within the recess.

The resilient clapper retainer may conveniently be disposed in the groove by resiliently defoming the clapper retainer, inserting it into the casing interior, and releasing the clapper retainerto expand into the groove and extend over the pin hanger recess.

One example of a valve according to the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a side elevational view of a swing-type clapper check valve in-which a clapper retainer in accordance with the instant invention is disposed; and, Figures 2 and 3 are, respectively, a plan view of the valve taken along section lines 2-2 of Figure 1 and an end view of the valve taken along section lines 3-3 of Figure 1, while Figure 2A is an enlarged view of a portion of Figure 2.

Throughout the following description similar reference numerals refer to similar elements in all Figures of the drawings.

Referring to the Figures, a swing-type clapper check valve generally indicated by reference character 10 is disposed in a flow control relationship with an inlet pipe 12 and an outlet pipe 14 (Figure 1). The valve 10 is connected to the inlet and outlet pipes at mounting flanges 16 and 18 provided on the valve 10 and the inlet and outlet pipes respectively, and secured-in position by any suitable connection arrangement, such as an array of bolts and studs 19 in a manner known-to those skilled in the art.

Typically, the check valve 10 finds utility in the control of relatively high velocity fluids carried by the pipes 12 and 14. These fluids, having velocities in the range of 40 to 60 feet per second, are utilized for well servicing and the like.

The check valve 10 includes a valve casing 20 adapted to define a relatively high pressure containment vessel through which the high velocity well servicing fluid may pass. The fluid flows in a direction indicated by the flow vector arrow V from the inlet pipe 12, through the valve 10 and to the outlet pipe 14. The flow vector arrow V is contained in a horizontal plane generally normal to the planes of Figures 1 and 3 and generally parallel to the plane of Figure 2.

The casing 20 is a substantially thick-walled memberfabricated, as by casting, from a high strength material such as ASTM A148 Gr. 150-125 steel. The casing 20 includes a bonnet or cover portion 22 which is removably connected, as by threads 24, at the upper portion of the casing 20. The interior of the casing 20 and the bonnet 22 cooperate to define a valve chamber 26 which communicates with the interior of the inlet pipe 12 through an inlet port 28 and to the interior of the outlet pipe 14through through an outlet port 30. A bleed opening 32 is provided through the bonnet 22 and permits communication between the valve chamber 26 and the atmosphere.

The bleed opening 32 is normally capped by a threaded stopper 34. Sealed integrity at the interfaces between the bonnet 22 and the casing 20 is insured by the provision of 0-rings 36 and 38. Of course, leakage may be inhibited from the chamber 26 by any other suitable sealing arrangement.

A valve seat 42 is defined along the circumferential edge of an axially inwardly extending neck portion 44 defined by the structure of the casing. The neck 44 cooperates with the interior of the casing 20 to define a cut out region 46 in which is disposed a clapper pin hanger 48. The hanger 48 is suitably affixed, as by welding or casting, to the interior of the casing 20. The clapper pin hanger 48 has recess 50L and 50R defined therein, the recesses 50L and 50R being respectively located on the left and right sides of the vertical centerline VCL of the valve 10 (Figure 3). The hanger 48 hasrims 49 surrounding the recesses 50 therein. A shoulder abutment 54 is also defined within the chamber 26 for a purpose made clearer herein.

Movably disposed within the valve chamber 26 is a valve member, or clapper, 58. The clapper is a substantially circular member when viewed from the end view (Figure 3) and-is thus configured to cover the inlet port 28 when the clapper 58 occupies the seated position (shown in solid lines in the Figures).

The clapper-58 may be provided with a rubberized covering 60,-if desired.

Attached to the clapper 58 is a clapper arm 64. The arm 64 has an opening 66 therethrough and receives a clapper pin 68. The pin 68 extends perpendicularly to the arm 64 and each end 70L and 70R thereof is provided with a bushing 72L and 72R, respectively.

The ends 70 and bushings 72 on the arm 64 are received within the recesses 50 of the hanger 48 and thereby act to support the clapper 58 in a depending relationship within the valve casing. As is appreciated by those with skill in the art, the clapper 58 is pivotally movable in a direction 74 (Figure 1) with respect to the.axis of its pin 68 from the seated to the open position (shown in dot-dash lines in the Figures). The pivotal movement of the clapper is facilitated by the bearing surfaces defined between the bushings 72 and the recesses 50 on the interior of the hangerA8.

- When in the seated position, as shown in solid lines in the Figures, the clapper 58 is operative to interdict fluid flow between the inlet pipe 12 and the outlet pipe 14. However, when the pressure of the fluid inroduced from the inlet pipe 12 in the direction of the vector V exceeds a predetermined pressure the clapper 58 pivotally responds to the force imposed thereby to pivot in the direction 74 toward the open position. In the full open position, as shown in dot-dash lines in the Figures, the portion of the clapper 58 distant from the clapper arm 64 is received in and abuts against the shoulder 54 thus forming a valve stop.Similarly, the movement of the clapper arm 64 due to the pivotal movement of the clapper valve 58 is accommodated by the contour of the recess 46 defined within the casing 20. Although those skilled in the art will appreciate that what has been heretofore described is substantially conventional swing check valve structure, it has been set forth in order to impart an understanding of the environment in which the instant invention is disposed.

As noted, in those instances when the check valve 10 is utilized in the control of relatively high pressure, high velocity well servicing fluids, the ends 70 of the clapper pin 68 having the bushings 72 thereon tend to separate from their engagement within the recesses 50 of the hanger 48. It is in order to prevent this occurrence and to maintain and to confine the clapper pin within the recess in the hanger that a clapper retainer generally indicated by reference character 80 is disposed in accordance with this invention. The clapper retainer 80 most preferably takes the form of a resilient wire ring-like element 82 fabricated from a suitable material, as spring steel.It is, of course, understood that any suitable material which provides some deformable resiliency may be utilized as the retainer 80 if appropriately configured in the manner set forth herein.

As best seen in Figures 2 and 2A, the ring-like resilient retainer element 82 is configured in a substantially closed circular arrangement with first and second ends 84L and 84R respectively therein.

The ends 84 are bent inwardly to define hook elements 86L and 86R. The undersides 88L and 88R (Figure 3) of the hook elements 86 are disposed in abutting relationship as at 90 with the top of the rims 49 of the hanger 48. The retainer element 82, and specifically the undersides 88 of the ends thereof, close the openings in recess of the hanger and confine the bushings 72 on the ends of the clapper pin 68 in order to contain the pin 68 in operative contact with the bottom of the recesses 50 of the hanger 48. That is, the undersides 88 of the retainer element 82 abut each rim 49 (Figures 2 ana 2A) of the recesses 50 in order to close the open top thereof to prevent the pin 68 from leaving the recesses 50 in the hanger.The undersides 88 of the retainer may simultaneously abut the top of the bushings 72 (if they are co-equal in height with the rims 49 of the recess) to assist in confining the pin 68 in the recess 50. In some instances, of course, the pin 68 (or bushings 72, if used) may be of such a large diameter as to protrude above the rims 49 of the hanger 48 and thus the retainer may bear only against the pin (or bushings) to confine the pin in the hanger. Conversely, in other instances, the recess 50 may be so deep as to completely accommodate the pin -(or bushing), and the retainer thus bears against only the rims of the recess. It is noted that both circumstances also lie within the contemplation of the invention.

The retainer element 82 is received within a groove 92 defined within the casing 20. The groove 92 is suitably machined or otherwise provided (e.g., as by casting) within the casing 20 and is disposed in a plane therein substantially parallel to the plane containing the flow vector V of the fluid flow. That is to say, the groove 92 is believed best disposed within the casing 20 in a plane 94 (Figure 3) substantially parallel to the horizontal plane containing the flow vector V of the valve 10. In such an orientation the groove 92 is spaced away from direct exposure to well servicing fluid.Consequently, such a disposition is believed to provide an advantage in enhancing the operative life of the retainer 80. of course, the retainer 82 may be received by a groove oriented in a plane other than the plane 94 and remain within the contemplation of this invention, so long as the undersides of the retainer abut the pin (or bushing) orthe rim of the recess or both to confine the pin within the recess. In this event, of course, it may be necessary to bend or otherwise configure the ring-like retainer element 82.

In order to insert and remove the retainer 80 from the groove 92 it is simple to remove the bonnet 22 from the housing 20 so as to permit access to be had to the valve chamber 26. The retainer element 82 is then grasped at the hooked ends 86 thereof and a deforming force is applied thereto in the direction of arrows 96 (Figure 2). The resiliency of the retainer element 82 permits response to the deforming force to occur so that the diametrical dimension of the retainer element 82 is reduced to permit insertion or removal of the retainer into the chamber 26 of the check valve 10. With the retainer element 82 introduced into a portion of the groove 92 the deforming force may be removed from the hooked ends 86 thereof. The resiliency of the retainer element 82 permits expansion of the diametrical dimension defined by the retainer and seats the retainer element 82 in the groove 92. The removal of the retainer element 82 is similarly effected.

In view of the foregoing it may therefore be appreciated that in accordance with this invention a resilient clapper retainer may be provided within a swing-type clapper check valve so as to close the recess defined in the hanger to prevent the clapper pin from leaving the recess as the clapper pivotally moves within the chamber and thus confine the pin therein. The retainer may abut the pin (or bushings, if used), the rims of the recess, or both as it confines the pin within the recess during the opening and closing movements of the clapper.

Having described a preferred embodiment of the invention those skilled in the art having benefit of the teachings herein disclosed may effect modifications thereto which are to be construed as lying within the contemplation of this invention as defined by the appended claims.

Claims (10)

1. A check valve having a casing provided with a fluid inlet port and a fluid outlet port, and forming a valve chamber; a valve clapper supported within the valve chamber, for pivotal movement between a seated position and an open position, by means of a clapper pin located in a pin hanger recess formed in the casing; and a resilient clapper retainer disposed in a retainer recess formed in the valve chamber, to confine the clapper pin in the pin hanger recess.

2. A check valve according to claim 1, in which the retainer recess is in the form of an elongate part annular groove.

3. A check valve according to claim 2, in which the elongate groove is disposed in a plane substantially parallel to the fluid flow path through the valve between the inlet and outlet ports.

4. A check valve according to any one of claims 1 to 3, in which the clapper retainer is in the form of a resiliently deformable ring-like element, the ring-like element being resiliently deformable to permit withdrawal from and insertion into the retainer recess.

5. A check valve according to claim 4, in which the clapper retainer is in the form of a circlip having first and second ends which cooperate with the hanger recess to confine the clapper pin in the hanger recess.

6. A check valve according to claim 5, in which the first and second ends are bent to form hooks which can be grasped by a suitable tool for resiliently deforming the circlip to reduce its peripheral dimension for insertion or withdrawal thereof from the retainer recess.

7. A check valve according to claim 5 or claim 6, in which the first and second ends of the circlip cooperate with the hanger recess by resiliently abutting the clapper pin to urge the clapper pin into the hanger recess.

8. A check valve according to claim 1, substantially as described with reference to the accompanying drawings.

9. A method of locating a hanger pin of a valve clapper in a pin hanger recess defined by a pin hanger within a check valve casing, which method comprises removably disposing a resilient clapper retainer in a groove provided in the casing interior such that the clapper retainer extends over the pin hanger recess to confine the hanger pin within the recess.

10. A method according to claim 9, in which the resilient clapper retainer is disposed in the groove by resiliently deforming the clapper retainer, inserting it into the casing interior, and releasing the clapper retainer to expand into the groove and extend over the pin hanger recess.