Reverse acting rupture disc with laser-defined electropolished line of weakness and method of forming the line of weakness

• US 7,600,527 B2
• Filed: 04/01/2005
• Issued: 10/13/2009
• Est. Priority Date: 04/01/2005
• Status: Active Grant

• Current Assignee: Fike Corporation
• Original Assignee: Fike Corporation
• Inventors: Shaw, Bon F., Krebill, Michael D., Stilwell, Bradford T., Leonard, Brent W.
• Primary Examiner(s): Lee; Kevin L
• Application Number:
  US11/096,466
• Publication Number:
  US 20060237457A1
• Time in Patent Office: 1,656 Days
• Field of Search: 137/68.26, 137/68.27, 137/910, 220/89.2, 220/203.08
• US Class Current: 137/68.27
• CPC Class Codes: B23K 2101/34 Coated articles , e.g. plated or painted; Surface treated articles
• CPC Class Codes: B23K 2103/04 Steel or steel alloys
• CPC Class Codes: B23K 2103/05 Stainless steel
• CPC Class Codes: B23K 2103/08 Non-ferrous metals or alloys
• CPC Class Codes: B23K 2103/16 Composite materials , e.g. fibre reinforced
• CPC Class Codes: B23K 2103/172 wherein at least one of the layers is non-metallic
• CPC Class Codes: B23K 2103/26 Alloys of Nickel and Cobalt and Chromium
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/0622 by shaping pulses
• CPC Class Codes: B23K 26/359 by providing a line or line pattern, e.g. a dotted break initiation line
• CPC Class Codes: B23K 26/364 for making a groove or trench, e.g. for scribing a break initiation groove
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: F16K 17/1606 of the reverse-buckling-type F16K17/1633 takes precedence
• CPC Class Codes: F16K 17/162 of the non reverse-buckling-type F16K17/1633 takes precedence
• CPC Class Codes: Y10T 137/1737 Reverse buckling
• CPC Class Codes: Y10T 137/1744 Specific weakening point

Abstract

A reverse acting rupture disc is provided having a laser defined electropolished line-of-weakness recess, and an improved method of forming an electropolished line-of-weakness recess in a reverse acting rupture disc that assures full opening of the disc upon reversal. A rupture disc blank is pre-bulged, final bulged, and then provided with a layer of resist material. A laser is used to remove at least a portion of the layer of resist material corresponding to a desired line-of-weakness recess in the concave face of the bulged rupture disc. The disc is then subjected to an electropolishing operation to remove metal from the lased area of the rupture disc, thereby forming a lustrous polished line-of-weakness recess in the disc of desired configuration and of a predetermined depth that is related to material thickness. The electropolished line of weakness is defined by spaced opposed channel portions separated by a central raised crown portion wherein the channel portions are of greater depth than the crown portion. The burst/reversal pressure of the disc having an electropolished line-of-weakness recess may be selectively controlled by varying the pre-bulging pressure on the disc.

Claims

1. A pressure relief device comprising:

a relatively thin metallic member having opposed faces;

one of said faces of the member being provided with an elongated line of weakness defined by a recess in said one face,

said elongated line-of-weakness recess being configured to present the outline of an over pressure relief area of the member,

said line-of-weakness recess being defined by spaced opposed channel portions separated by a central raised crown portion, said channel portions being of greater depth than said crown portion.

2. A pressure relief device as set forth in claim 1 wherein said line-of-weakness recess has an electropolished surface.

3. A pressure relief device as set forth in claim 1 wherein said line-of-weakness recess is substantially W-shaped in cross section.

4. A pressure relief device as set forth in claim 3 wherein said crown portion is of generally inverted U-shape.

5. A pressure relief device as set forth in claim 1 wherein the maximum depth of the line-of-weakness recess is at least about 70%±

25% of the cross sectional thickness of the member.

6. A pressure relief device as set forth in claim 1 wherein the maximum depth of the line-of-weakness recess is at least about 70%±

10% of the cross sectional thickness of the member.

7. A pressure relief device as set forth in claim 1 wherein the maximum depth of the line-of-weakness recess is at least about 70%±

5% of the cross sectional thickness of the member.

8. A pressure relief device as set forth in claim 2 wherein said surface of the line-of-weakness recess is a passivated electropolished surface.

9. A pressure relief device as set forth in claim 1 wherein the width of the line-of-weakness recess is from about 0.002 in. to about 0.1 in.

10. A pressure relief device as set forth in claim 1 wherein the width of the line-of-weakness recess is from about 0.010 in. to about 0.080 in.

11. A pressure relief device as set forth in claim 1 wherein the depth of the channel portions are substantially uniform throughout the length of the recess.

12. A pressure relief device as set forth in claim 1 wherein the width of each of the channel portions of the recess is approximately 25% of the overall width of the recess.

13. A pressure relief device as set forth in claim 1 wherein said metallic member has a bulged portion, said line-of-weakness recess being provided in the bulged portion of the metallic member.

14. A pressure relief device as set forth in claim 13 wherein the bulged portion of the metallic member has a convex face and a concave face, said line-of-weakness recess being provided in the concave face of the metallic member.

15. A pressure relief device as set forth in claim 14 wherein said line-of-weakness recess is located adjacent the perimeter of the bulged portion of the metallic member.

16. A pressure relief device as set forth in claim 14 wherein said line-of-weakness recess is of generally C-shaped configuration.

17. A pressure relief precurser product comprising:

a sheet of metallic material presenting a face; and

a layer of resist material applied to said face, a predetermined area of said resist material being eroded such that a residuum of said resist material exists in said area having a thickness less than other portions of said layer, said residuum in contact with said face in said predetermined area.

18. A pressure relief precurser product as set forth in claim 17 wherein said resist material is eroded along a predetermined line, said residuum in contact with said face along said predetermined line.

19. A pressure relief precurser product as set forth in claim 17 wherein said resist material is eroded along a generally C-shaped line, said residuum in contact with said face along said C-shaped line.

20. A pressure relief precurser product as set forth in claim 17 wherein said predetermined eroded area is formed in said resist material by a laser.

21. A pressure relief precurser product as set forth in claim 17 wherein said sheet of metallic material has a bulged portion, said predetermined eroded area being in the bulged portion of the metallic sheet.

22. A pressure relief precurser product as set forth in claim 21 wherein said bulged portion of the sheet of metallic material has opposed convex and concave faces, said predetermined area being on the concave face of the sheet of metallic material.

23. A pressure relief device comprising:

a relatively thin metallic member having opposed faces;

one of said faces of the member being provided with an elongated line of weakness defined by a recess in said one face,

said elongated line-of weakness recess being configured to present the outline of an over pressure relief area of the member,

said line-of-weakness recess being defined by spaced opposed side wall surfaces joined by a bottom wall surface, said surfaces of the line-of-weakness recess having a lustrous surface finish that is no greater than about 4 microinches of average deviation from the mean surface.

24. A pressure relief device as set forth in claim 23 wherein said line-of-weakness recess has a lustrous surface finish that is no greater than about 2 microinches of average deviation from the mean surface.

25. A pressure relief device comprising:

a relatively thin metallic member having opposed faces;

one of said faces of the member being provided with an elongated line of weakness defined by a recess in said one face,

said elongated line-of-weakness recess being configured to present the outline of an over pressure relief area of the member,

said line-of-weakness recess being defined by spaced opposed side wall surfaces joined by a bottom wall surface, said surfaces of the line-of-weakness recess having a lustrous surface finish at least about 6 times smoother than the surface finish of the metallic member.

26. A pressure relief device as set forth in claim 25 wherein said line-of-weakness recess has a lustrous surface finish at least about 8 times smoother than the surface finish of the metallic member.