US3463196A - Flange protector - Google Patents

Description

1969 E. T. RICHARDSON 3,463,196

FLANGE PROTECTOR Filed Sept. 8, 1967 United States Patent US. Cl. 138-96 Claims ABSTRAT OF THE DISCLOSURE A protector for a flange which has an annular groove and a circle of tapped holes arranged concentrically of the groove in one side of the flange. The protector comprises a thin ring for disposal over the one side of the flange and having plugs extending from the side thereof adjacent the flange for fitting closely within certain of the flange holes. Holes through the ring are adapted to be aligned with the remaining holes in the flange. Annular ridges extend from equal diameter portions of opposite sides of the ring, with the ridge on the same side of the ring as the plugs being adapted to fit closely within the groove of the flange.

This invention relates to an improved device for protecting a flange against corrosion.

In the drilling of an oil or gas well, the drill string extends through the bore of one or more blowout preventers supported above the wellhead. Frequently, the uppermost preventer is of the annular type which has a circle of tapped holes about its upper flange for securing additional equipment above it. Also, there is an annular groove in the upper flange concentrically within the circle of holes for receiving a seal ring between the flange and the additional equipment.

This additional equipment, which may be another annular-type preventer, has a flange on its lower end for connection to the upper flange on the lower preventer by studs received in the full circle of holes. Also, the seal ring is a standard metal A.P.I. ring for forming a pressure-tight connection between the ring groove on the upper flange of the lower preventer and a matching ring groove in the lower flange of the upper preventer.

Usually, however, a bell nipple flange is connected to the upper flange of the annular preventer and, in the use of this equipment, drilling fluid circulated downwardly through the drill string returns through the annulus between the string and the preventer bore and out through the bell nipple flange. Since this does not require a pressure-tight connection between the flanges, the flanges are normally connected by only a few studs, thereby leaving open the unused holes in the circle on the upper flange of the preventer. Also, packing of a less permanent nature than the A.P.I. ring may be disposed between the ring grooves of the flanges.

It has been found, however, that the open holes in the preventer flange, and especially the threads thereof, as well as the temporary packing in the ring groove of the preventer, may be corroded by the drilling fluid. This requires costly repairs of the equipment and also loss of use of the equipment during the downtime. When the groove is protected against corrosion by a standard A.P.I. ring, the severe vibrations which occur at the upper end of the wellhead during drilling operations often deform the ring grooves to such an extent as to render them incapable of holding a seal with the ring. Still further, of course, the ring groove and the stud holes in the preventer flange are susceptible of corrosion and 3,463,196 Patented Aug. 26, 1969 other damage when the preventer is not in use and stored outside, as is often the case.

An object of this invention is to avoid these costly and time-consuming repairs.

A more particular object of this invention is to provide a simple and inexpensive device for protecting both the tapped holes and ring groove of a flange against corrosion, either when a bell nipple flange in connected thereto or when the equipment is out of service.

A further object is to provide such a device which protects the ring groove against corrosion without damaging same, as during vibrations encountered in drilling operations.

These and other objects are accomplished, in accordance with the illustrated embodiment of the present invention, by a thin ring which is adapted to be disposed over one side of the flange and which has plugs extending from the side thereof adjacent the flange for fitting closely within the open tapped holes of the flange. This ring also has holes therethrough which are adapted to be aligned with the remaining flanged holes, when the ring is so disposed, so as to receive the studs which secure equipment above the flange. There are also annular ridges which extend from equal diameter portions of opposite sides of the ring, the lower ridge being adapted to fit closely within the ring groove of the flange and the upper ridge being adapted to fit closely within the matching ring groove of the additional equipment secured above the flange.

The ring is preferably made of a resinous plastic material which will not corrode when exposed to the drilling fluid, and which will also fill the ring grooves in the flange and additional equipment without damaging same, even when subjected to the vibrations of a drilling operation. More particularly, the ring is of such extent and so shaped that it is engaged on its opposite sides both radially inwardly and radially outwardly of the ridges to provide a firm support between the flange and the additional equipment.

In the drawings, wherein like reference characters are used throughout to designate like parts:

FIG. 1 is a vertical sectional view as seen along broken line 1-1 of FIG. 2, of the upper flange of an annular type blowout preventer having a bell nipple flange secured thereabove and a flange protector ring constructed in accordance with the present invention arranged between the two flanges;

FIG. 2 is a cross-sectional view of the drilling equipment of FIG. 1, as seen along broken line 22 of FIG. 1; and

FIG. 3 is a detailed view of a part of the flange protector, as seen in the encircled area indicated at 3 in FIG. 1.

With reference now to the details of these drawings, the annular blowout preventer 10 may be of any well known type, such as that shown on pages 2653-2664 of volume 2 of the 1966-67 issue of the Composite Catalog of Oilfield Equipment and Services. More particularly, the portion of this preventer which is shown in FIGS. 1 and 2 is the upper flange thereof which surrounds the bore 11 through the preventer. As previously mentioned, the preventer is connected to the upper end of the wellhead and, in use, a drill string is adapted to be extended downwardly through the bore 11 of the preventer.

During the drilling operation, drilling fluid is circulated downwardly through the drill string and upwardly in the annulus between the drill string and the bore 11. This drilling fluid then flows outwardly from the well through a bell nipple flange 12 which, as shown in FIG. 1, is connected to the upper flange of the preventer. More partic- 3 ularly, the flange 12 has a bore 13 therethrough adapted to be aligned with the bore 11 through the preventer when so secured.

As shown in FIGS. 1 and 2, the flange 12 is connected to the upper flange of the preventer by studs 14 received through holes 15 of a circle of holes about the flange 12 and anchored in holes 16 of a circle of equally spaced apart, tapped holes arranged in the upper side of the preventer flange concentrically of the bore 11. These studs are threaded at opposite ends so that the lower end may be threaded into the holes 16 and nuts 17 may be threaded down over the upper ends thereof for forcing the lower side of the flange 12 down against the upper side of the preventer flange.

As well known in the art, this equipment is massive and considerable energy is required in securing each stud. Consequently, it is the usual practice to make up only a few of these studs in securing this flange 12 to the preventer flange, because the joint therebetween does not have to be pressure tight. As is apparent from FIG. 2, this leaves a majority of the tapped holes 16 in the upper side of the preventer flange open or empty, and thus exposed to corrosive materials such as the drilling fluid.

The preventer flange has a ring groove 18 about its upper side which is located concentrically within the circle of holes 16 and relatively near the bore 11 of the preventer, and the under side of the flange 12 has a matching groove 19 thereabout for disposal opposite the groove 18. As is also well known in this art, these grooves are adapted to receive a standard metal A.P.I. ring (not shown) therebetween for forming a pressure-tight seal between the flanges. This, of course, is one reason for the considerable energy which is required in making up the studs, because the metal ring must be deformed into sealing engagement with the ring grooves in the two flanges.

As previously described, the flange protector of the.

present invention comprises a thin ring 20 which, in use, is disposed between the opposite faces of the flange 12 and the preventer flange. As shown in FIGS. 1 and 2, this ring 20 has a circle of plugs 21 extending from the lower side of the groove and holes 22 therethrough intermediate certain of the plugs in the circle.

More particularly, these plugs are cylindrical and of a diameter just less than the inner diameter of the threads in the holes for fitting closely therein. The holes 22, on the other hand, are of a diameter just slightly greater than the outer diameter of the threads on the lower ends of the studs 14 for receiving such studs closely therethrough. Thus, in order that they will be aligned with corresponding holes 16 in the preventer flange, adjacent plugs and holes in the ring 20 are equally spaced from one another about the circle of holes 16.

The plugs 21 correspond in number to the open or empty holes 16 in the preventer flange. That is, the plugs are equal in number to the total number of tapped holes less the number of studs 14 to be used in securing the flange 12 to the preventer flange. Consequently, in use, all the holes 16 are either filled by the studs 14 or by the plugs 21.

The ring 20 also has annular ridges 23 and 24 on its lower and upper sides, respectively, for disposal within the ring grooves 18 and 19 of the preventer flange and bell nipple flange. More particularly, these ridges are of substantially the same size and shape as the opposite ends of the standard metal A.P.I. ring so that they fit closely within the flange grooves 18 and 19. Consequently, when the flange 12 is secured by studs 14 to the preventer flange, the ridges 23 and 24 on the ring 20 form a fluid barrier between the bores 11 and 13 and the circle of tapped holes 16 in the preventer flange.

As previously noted, this ring is preferably made of a resinous plastic material, which, for example, may be urathane, which is tough, durable, and corrosion-resistant. At the same time, this material is sufiiciently deformable to permit it to conform to the ring grooves 18 and 19,

without damaging them under conditions of vibration due to the drilling operations.

As also shown in FIG. 1, the opposite sides of the ring 20 radially outwardly of the ridges 23 and 24 and about the plugs 21 are engaged by opposite sides of the flanges as the flange 12 is connected to the preventer flange by means of the studs 14. This then provides a firm support for the flanges, especially during the aforementioned vibrations. Additionally, the portion of the ring intermediate the ridges 23 and 24 and the circle of plugs and holes provides a further barrier to fluids which might escape past the ridges toward the circle of plugs in the holes.

In the interest of providing a firm support for the en tire width of the sides of the flanges, and thereby further inhibiting intrusion of drilling mud between the flanges, the ring 20 extends radially inwardly from the ridges 23 and 24 and outwardly from the circle of plugs and holes a distance suflicient to dispose its inner and outer edges substantially flush with the bores through the flanges as well as the outer diameters of the flanges.

A shown by the detailed view of FIG. 4, there is a double conical taper between each plug 21 and the lower side of the flange protector ring 20. The purpose of this is to fit and accommodate with a similarly shaped surface at the intersection of the upper ends of the tapped holes 16 and the upper side of the preventer flange.

As previously mentioned, when the preventer is not in use, the protector ring 20 may also be useful in preventing corrosion of the ring groove 18 as well as the tapped hole 16. It will be obvious that this requires some additional parts, however, since there would be no plugs 21 for filling the tapped hole 16 which, in use of the flange protector on a blowout preventer flange, were filled by the studs 14. These additional parts may be specially fabricated or may be made up as required in the shop or in the field.

From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the article.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

1. For use in protecting a flange having an annular groove and a circle of tapped holes in one side thereof arranged concentrically of the groove, a device comprising a thin ring adapted to be disposed over said one side of the flange and having plugs extending from the side thereof adjacent the flange for fitting closely within certain of said tapped holes, said ring also having holes therethrough adapted to be aligned with the remaining tapped holes for receiving securing means, and annular ridges extending from equal diameter portions of opposite sides of the ring, the ridge on the same side of the ring as the plugs being adapted to fit closely within the groove of the flange.

2. A flange protector, for use in combination with a flange having a central bore, an annular groove about and concentric with the bore, and a plurality of tapped holes circumferentially spaced and concentric with said bore, said protector comprising a thin ring having a circle of plugs extending from one side thereof and adapted to be aligned with certain of said tapped holes in said flange, a plurality of holes through said ring on said circle intermediate certain of the plugs adapted to be aligned with the remaining tapped holes for receiving securing means, said circle being concentric with the axis of the ring and adjacent plugs and holes being equally spaced from one another about the circle, and an annular ridge extending 5 from each side of the ring concentrically within said circle, each said ridge being of the same radius and the ridge on the same side of the ring as the plugs being adapted to fit closely within the groove of the flange.

3. A flange protector of the character defined in claim 2, wherein the ring, plugs and ridges are of a resinous plastic material.

4. A flange protector of the character defined in claim 2, wherein the ring, plugs and ridges are formed of a single piece of the same material.

5. A flange protector of the character defined in claim 2, wherein each plug is connected to the ring by a portion which tapers outwardly from the plug toward the ring.

References Cited UNITED STATES PATENTS Hewitt et a1. 277--166 XR Scherer.

Gray 13896 Butcher 285368 XR Barton 16685 Olson 277-227 XR US. Cl. X.R.

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