Flange for pressure vessel with undercut fillet

Patent metadata

Field	Value
Publication number	US-12012190-B2
Application number	US-202117411259-A
Country	US
Kind code	B2
Filing date	Aug 25, 2021
Priority date	Aug 25, 2021
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

A flange for a pressure vessel includes a rim, a sealing seat, and an undercut fillet. The rim has an annular surface for abutting an annular end of a cylindrical wall of the pressure vessel. The sealing seat has a cylindrical surface for abutting an inner surface of the cylindrical wall of the pressure vessel nearby the annular end. The undercut fillet is disposed between the rim and the sealing seat. A concave surface of the undercut fillet extends the annular surface of the rim radially inward and then curves back outward to intersect the cylindrical surface of the sealing seat. The undercut fillet of the flange helps distribute stress produced from a pressure differential between the inside and outside of the pressure vessel.

First claim

We claim:

1. A flange for a pressure vessel comprising:
a rim with an annular surface for abutting an annular end of a cylindrical wall of the pressure vessel;
a sealing seat with a cylindrical surface for abutting an inner surface of the cylindrical wall of the pressure vessel nearby the annular end;
an undercut fillet between the rim and the sealing seat, wherein a concave surface of the undercut fillet extends the annular surface of the rim radially inward and then curves back outward to intersect the cylindrical surface of the sealing seat,
wherein the concave contour includes a sequence of arc segments, with each of the arc segments having a respective radius selected to distribute a stress in a distribution along the concave contour and to limit a maximum concentration of the stress in the distribution, the stress produced when an external pressure outside the pressure vessel is higher than an internal pressure inside the pressure vessel; and
wherein the sequence of arc segments includes a first arc segment and a second arc segment, the first arc segment adjoining an inner edge of the annular surface of the rim at a first continuous slope and the second arc segment adjoining the first arc segment at a second continuous slope.

2. The flange of claim 1 , wherein the concave surface of the undercut fillet is shaped to form a void between the concave surface and the inner surface of the cylindrical wall of the pressure vessel when the annular surface of the rim abuts the annular end of the cylindrical wall of the pressure vessel and the cylindrical surface of the sealing seat abuts the inner surface of the cylindrical wall of the pressure vessel.

3. The flange of claim 1 , wherein the concave surface of the undercut fillet is disposed inside an imaginary solid cylinder, which has a curved outside encompassing the cylindrical surface of the sealing seat and a flat end within a plane encompassing the annular surface of the rim.

4. The flange of claim 1 , wherein the concave surface is shaped to distribute a stress in a distribution around the concave surface and to limit a maximum concentration of the stress in the distribution, the stress produced when an external pressure outside the pressure vessel is higher than an internal pressure inside the pressure vessel.

5. The flange of claim 1 , wherein the concave surface of the undercut fillet is rotationally symmetric about a symmetry axis, and the concave surface of the undercut fillet has a concave contour in a cross-sectional plane encompassing the symmetry axis.

6. The flange of claim 5 , wherein the concave contour is shaped to distribute a stress in a distribution along the concave contour and to limit a maximum concentration of the stress in the distribution, the stress produced when an external pressure outside the pressure vessel is higher than an internal pressure inside the pressure vessel.

7. The flange of claim 1 , wherein the sequence of arc segments is optimized to minimize the maximum concentration of the stress in the distribution, so that the respective radius R 1 of the first arc segment equals 0.446×L and the respective radius R 2 of the second arc segment equals 0.876×L, where L equals 0.040×R and is an axial length of the concave contour of the undercut fillet, and R is an outer radius from the symmetry axis of the cylindrical surface of the sealing seat and an inner radius of the inner surface of the cylindrical wall of the pressure vessel, and so that the second continuous slope between the first and second arc segments has an angle of 42° from the symmetry axis in the cross-sectional plane.

8. A flange for a pressure vessel comprising:
a rim with an annular surface for abutting an annular end of a cylindrical wall of the pressure vessel;
a sealing seat with a cylindrical surface for abutting an inner surface of the cylindrical wall of the pressure vessel nearby the annular end;
an undercut fillet between the rim and the sealing seat, wherein a concave surface of the undercut fillet extends the annular surface of the rim radially inward and then curves back outward to intersect the cylindrical surface of the sealing seat
wherein the concave contour includes a sequence of arc segments, with each of the arc segments having a respective radius selected to distribute a stress in a distribution along the concave contour and to limit a maximum concentration of the stress in the distribution, the stress produced when an external pressure outside the pressure vessel is higher than an internal pressure inside the pressure vessel; and
wherein the sequence of arc segments includes a first, second, third, and fourth arc segment,
the first arc segment adjoining an inner edge of the annular surface of the rim at an offset X radially outward from the cylindrical surface of the sealing seat and at a first continuous slope perpendicular to the symmetry axis in the cross-sectional plane, the first arc segment having the offset X≈0.130×L and a radius R 1 ≈0.446×L, where L≈0.040×R is an axial length of the concave contour of the undercut fillet and R is an outer radius from the symmetry axis of the cylindrical surface of the sealing seat,
the second arc segment adjoining the first arc segment at a second continuous slope having a length Y≈0.054×L and an angle of 42° from the symmetry axis in the cross-sectional plane, the second arc segment having a radius R 2 ≈0.876×L,
the third arc segment adjoining the second arc segment at a third continuous slope substantially parallel to the symmetry axis in the cross-sectional plane, the third arc segment having a radius R 3 ≈0.200×L, and
the fourth arc segment adjoining the third arc segment at a fourth continuous slope and a linear extension adjoining the fourth arc segment at a fifth continuous slope perpendicular to the symmetry axis in the cross-sectional plane, the fourth arc segment having a radius R 4 ≈0.260×L, the linear extension perpendicularly intersecting the cylindrical surface of the sealing seat and having a length Z=0.244×L.

9. A flange for a pressure vessel comprising:
a rim with an annular surface for abutting an annular end of a cylindrical wall of the pressure vessel;
a sealing seat with a cylindrical surface for abutting an inner surface of the cylindrical wall of the pressure vessel nearby the annular end;
an undercut fillet between the rim and the sealing seat, wherein a concave surface of the undercut fillet extends the annular surface of the rim radially inward and then curves back outward to intersect the cylindrical surface of the sealing seat; and
wherein the sealing seat includes one or more grooves in the cylindrical surface of the sealing seat, each of the grooves for receiving an O-ring for forming a seal between the cylindrical surface of the sealing seat and the inner surface of the cylindrical wall of the pressure vessel.

10. The flange of claim 9 , wherein the sealing seat further includes a plurality of threaded recesses in the cylindrical surface of the sealing seat between the grooves and an intersection at which the concave surface of the undercut fillet intersects the cylindrical surface of the sealing seat, the threaded recesses for receiving a plurality of threaded fasteners for fastening the cylindrical wall of the pressure vessel to the flange.

11. The flange of claim 9 , wherein an inner radius of the annular surface of the rim from a symmetry axis is greater than an outer radius of the cylindrical surface of the sealing seat from the symmetry axis, which is the symmetry axis of rotational symmetry of both the cylindrical surface of the sealing seat and the annular surface of the rim.

12. An endcap including the flange of claim 9 ,

Assignees

• Us Navy
• Us Navy

Inventors

• Caldwell Jesse T
• Wiedemeier Brandon J

Classifications

• B63G8/001

  Underwater vessels adapted for special purposes, e.g. unmanned underwater vessels; Equipment specially adapted therefor, e.g. docking stations (self-propelled or direction controlled diving chambers with mechanical link to a base B63C11/42) · CPC title

• B63G2008/002

  unmanned · CPC title

• F17C13/06

  Closures, e.g. cap, breakable member ({for autoclaves B01J3/03}; closures for {large} containers in general B65D {B65D90/54}; {for pressure vessels in general F16J13/00}) · CPC title

• F17C2205/0311

  Closure means · CPC title

• F17C2260/011

  Improving strength · CPC title