Methods for decreasing stress in flange bolting

Patent metadata

Field	Value
Publication number	US-11959567-B2
Application number	US-201917267250-A
Country	US
Kind code	B2
Filing date	Aug 30, 2019
Priority date	Aug 30, 2018
Publication date	Apr 16, 2024
Grant date	Apr 16, 2024

Abstract

Systems: and methods for decreasing bending stress in flange bolting for a connection between a flange and an adjacent piece of equipment is provided. The flange connection includes a single flange with multiple bolts extending: therethrough. The bolts are threaded into the adjacent piece of equipment at one end, and a nut is disposed at an opposite end. of each bolt to provide a means for tightening and/or securing the flange connection. The equipment to which the flange is attached may include subsea well equipment with relatively large outer diameters. The disclosed flange connection utilizes: an initial region of a counterbored (or unthreaded) hole in the mating equipment piece just prior to the start of the thread formed through the equipment. Additionally, a compound hub flange connection is disclosed to further reduce the bending stress on the bolts.

First claim

What is claimed is:

1. A system, comprising:
an upper compound hub flange comprising an aperture, an inner hub face, and an outer hub face, wherein the outer hub face is arranged radially outward with respect to the inner hub face;
a lower compound hub flange adjacent the upper compound hub flange and having an aperture extending therethrough, wherein the aperture is aligned with the aperture of the upper compound hub flange, wherein the lower compound hub flange further comprises an inner hub face and an outer hub face, wherein the inner hub face and the outer hub face of the lower compound hub flange are disposed adjacent to the inner hub face and the outer hub face of the upper compound hub flange, and wherein each of the apertures is arranged radially outward with respect to each of the outer hub faces; and
a bolt extending through the apertures of the upper compound hub flange and the lower compound hub flange to couple the upper compound hub flange to the lower compound hub flange;
wherein a circumferential groove is formed between the inner hub faces of the upper and lower compound hub flanges and the outer hub faces of the upper and lower compound hub flanges when the bolt couples the upper compound hub flange to the lower compound hub flange, wherein the circumferential groove does not provide a sealing surface; and
wherein there is a gap between the outer face of the upper compound hub flange and the outer face of the lower compound hub flange.

2. The system of claim 1 , wherein the circumferential groove is hexagonal in shape when viewed from a circumferential direction.

3. The system of claim 1 , wherein the circumferential groove provides increased flexibility between the inner and outer hub faces of each of the upper and lower compound hub flanges to improve flange performance when the system is subjected to a thermal gradient.

4. The system of claim 1 , wherein there is a gap between the aperture of the upper compound hub flange and the aperture of the lower compound hub flange, wherein the bolt extends through the gap.

5. The system of claim 1 , wherein a nut is threaded on each end of the bolt to secure the upper compound hub flange and the lower compound hub flange in compression.

6. The system of claim 1 , wherein a gasket is disposed between the upper compound hub flange and the lower compound hub flange.

7. A system comprising;
a compound hub flange comprising an aperture extending therethrough, an inner hub, and an outer hub, wherein a groove is formed between the inner hub and the outer hub, wherein the groove does not provide a sealing surface;
a piece of equipment adjacent the compound hub flange and having an aperture extending therethrough and aligned with the aperture of the compound hub flange, wherein the piece of equipment has a continuous face facing the compound hub flange and contacting both the inner hub and the outer hub of the compound hub flange; and
a bolt extending through the compound hub flange and threaded into the piece of equipment to connect the compound hub flange to the piece of equipment.

8. The system of claim 7 , wherein a first axial portion of the aperture through the piece of equipment is unthreaded, and wherein a second axial portion of the aperture through the piece of equipment is threaded.

9. The system of claim 8 , wherein the first axial portion has a length of about 3 inches.

10. The system of claim 8 , wherein the first axial portion has a length of about 1.5 inches.

11. The system of claim 7 , wherein the aperture of the piece of equipment is fully threaded.

12. The system of claim 7 , wherein the groove provides increased flexibility between the inner hub and outer hub of the compound hub flange to improve flange performance when the system is subjected to a thermal gradient.

13. The system of claim 7 , wherein there is a gap between the aperture of the compound hub flange and the aperture of the piece of equipment, wherein the bolt extends through the gap.

Assignees

• Dril Quip Inc

Inventors

• Manning Mark A
• Rye Justin
• Santos Flavio

Classifications

• F16L23/032 Primary

  characterised by the shape or composition of the flanges · CPC title

• E21B17/046

  with ribs, pins, or jaws, and complementary grooves or the like, e.g. bayonet catches · CPC title

• F16L23/036 Primary

  characterised by the tensioning members, e.g. specially adapted bolts or C-clamps · CPC title

• F16L23/02

  the flanges being connected by members tensioned axially (F16L23/12 takes precedence) · CPC title

• F16B7/18

  using screw-thread elements {(F16B7/025 takes precedence; for turnbuckles F16B7/06)} · CPC title