CA1304650C - Method of manufacturing metal rupture discs - Google Patents
Method of manufacturing metal rupture discsInfo
- Publication number
- CA1304650C CA1304650C CA 545584 CA545584A CA1304650C CA 1304650 C CA1304650 C CA 1304650C CA 545584 CA545584 CA 545584 CA 545584 A CA545584 A CA 545584A CA 1304650 C CA1304650 C CA 1304650C
- Authority
- CA
- Canada
- Prior art keywords
- rupture disc
- laser
- rupture
- line
- disc
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K17/00—Safety valves; Equalising valves, e.g. pressure relief valves
- F16K17/02—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side
- F16K17/14—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side with fracturing member
- F16K17/16—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side with fracturing member with fracturing diaphragm ; Rupture discs
- F16K17/1606—Safety valves; Equalising valves, e.g. pressure relief valves opening on surplus pressure on one side; closing on insufficient pressure on one side with fracturing member with fracturing diaphragm ; Rupture discs of the reverse-buckling-type
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Plasma & Fusion (AREA)
- Safety Valves (AREA)
- Laser Beam Processing (AREA)
Abstract
ABSTRACT
This invention provides a method of creating lines of weakness in rupture discs using a laser beam, to provide improved results for consistency for the lines of weakness compared to conventional mechanical methods.
This invention provides a method of creating lines of weakness in rupture discs using a laser beam, to provide improved results for consistency for the lines of weakness compared to conventional mechanical methods.
Description
~3~ S~
This invention relates to a method of manufacturing metal rupture discs; more particularly, -this invention relates to an improved method of crea-ting lines of weak-ness or score lines in metal rupture discs.
In the prior art, rupture discs are normally pro-vided with weakened lines - i.e. the lines which rup-ture, by mechanical means. Typically, the material forming the weakened lines will be made by a blade pres-sing or scoring the metal. There are several disadvan-tages to this known type of process which basically in-volve the difficulty of obtaining constantly reproduc-ible results for given rupture pressures; also, such conventional techniques are quite expensive and result in a fairly costly product.
A more recent proposal is that disclosed in Canadian Patent 1,088,285 wherein rupture discs are pro-vided with a line of weakness by using a corrosive fluid to create scores in the metal. This technique is stated to provide improved results and may be more economical than the conventional techniques.
The present invention provides a further alterna-tive for creating a line of weakness, and according to this invention, the method of providing a line of weak-ness in a rupture disc comprises providing a metal sec-tion of a desired configuration, exposing preselected areas of said metal disc to a laser beam to create a displacement of metal in said section or to provide a weakened metal section.
In greater detail of the present invention, appli-cant has found that improved results can be obtained by forming the lines of weakness in a rupture disc using a laser beam, in which the laser is of a type wherein either a given depth of metal is removed by the action of the laser beam or alternately, the laser beam is eff-ective to alter the properties of the metal and create a line of weakness in the metal.
9~
~4~SO
The present invention is appllcable to various types of rupture discs such as -those well known in the art and used for the purpose of rup-turing under pre-determined pressure limits. Typically, such rupture discs may be the so-called conven-tional tension discs or a reverse buckling compression loaded disc.
One advantage of the present invention is that the rupture disc configuratlon can be initially formed and then subjected to the action of a laser beam or al-ter-nately, a laser beam can be used to create a line of weakness in sheet metal which can then be formed into a rupture disc.
A typical rupture disc normally has several lines of weakness and accordingly, conventional patterns forming the lines of weakness can be created using the method of the present invention.
With the method of the present invention, the use of a laser beam for creating the lines of weakness as noted above, may be one of two different types - a first type being where the heat generated by the laser beam on the surface of the material is such that metal is dis-placed from the material to create a line of weakness in the form of a groove or the like. To this end, basic-ally the material is removed along a predetermined sec-tion from the substrate material to create the line of weakness, it being understood that such lines of weak-ness do not extend through to the opposed surface of the substrate material.
The type of laser used for this invention may be any so-called "hot laser" which produces a light beam using a high temperature for the purpose of creating the line of weakness. Typically, the type of laser equip-ment may be any suitable laser equipment known to those skilled in the laser art for this purpose although pre-ferred equipment is that known as an ND Yag laser, which is a bottom end laser, or a C02 laser.
~3~
In an al-ternate embodiment, -the laser may be used so that the beam generated by the laser device creates a line of stress ~ i.e. a weakened line, in the rnaterial without displacing or removing any of the material. In this way, a rupture disc will not have any score lines on it per se but will be rupturable at a prede-termined pressure depending on the amount of stress created in the material. In turn, this will depend on the actual material used for the rupture disc and this may be var-ied according to the pressure rupture characteristics desired in the rupture disc. In one embodiment, accord-ing to the present invention, the method can initially form the rupture disc into its desired configura-tion, and then subject the resulting contoured product to the action of a laser beam. Thus, pre-formed rupture discs can be employed which are produced by conventional tech-niques in terms of their contours and configurations.
Substantially more uniform rupture characteristics can be obtained using the techniques of the present inven-tion, and as such, the resulting rupture discs provide a higher degree of reliability for rupturing at a given pres-sure. In addition, the present invention also provides an economical alternative method to conventional knife-blade scoring techniques relying on mechanical methods, or electro deposition methods.
In carrying out the method of the present invention, the weakened lines may be created in any rupture disc on either one or both sides of the rupture disc, as may be required for any given purpose. Thus, in some cases, it is desirable to provide a weakened line(s) in the concave or convex side only but in other cases, it may be desir-able to provide such weakened lines in both sides of the disc.
The rupture discs which are used for the method of the present invention can be made out of any suitable conventional material as is well known to those skilled ~a3~ 0 in the art; typically these are various types of metal-lic materials and more speciEically, are metallic alloys.
In using the method to create the lines of weakness, either the laser device can be movably mounted to rotate or traverse about a laser disc or disc blank which is otherwise mounted in a fixed manner or alterna-tely, the rupture disc or disc blank may be mounted for movement about a fixed laser beam. Suitable devices for rnovement of the laser or of the rupture disc or blank are known and can be used for this purpose; such devices will create a path of movement corresponding to a pre-deter-mined design or pattern to provide the desired line of weakness or stress in the rupture disc. Normally, sev-eral lines of weakness are provided in a given pattern eg. typically such lines may radiate from a central area of the rupture disc outwardly towards the periphery of the disc - other patterns are employed and it will be evident to those skilled in the art which pattern can be employed for any given purpose.
As rupture disc can be designed to rupture at dif-ferent pressures, which in turn partially depends on the type of metallic substance used to form the rupture disc, the laser treatment can be varied and create lines of weakness of different characteristics to create diff-erent bursting characteristics. For example, applicant has found that laser power variations using the ND Yag laser device with power settings of under 10 Joules can suffice for creating different types of lines of weak-ness.
130~
E _MPLE'S
A plurality of sheet me-tal discs were formed from "Inconel 600*" ma-terial of a thickness of 10,000's of an inch, into flat sea-ted rupture discs, each having a dia-meter of 2 inches. Using an ND Yag laser, each of the pre-formed rupture discs were laser scored with a conven-tional score pattern using a constant power level to form a series of scored tension-type rupture cliscs. The discs were then tested to determine the burst pressure, by sec-uring the individual rupture discs into a set-up in a test jig. Pressure was applied to the individual rupture discs using a variable pressure source; in the following table, the results given are for burst pressure of diff-erent series (A-C) of pre-formed discs, each series of discs being formed as described herein by laser treatment Each series of rupture discs was found, during test-ing, to successfully rupture along the pre-determined score lines created by the laser treatment, with the burst pressures being noted for the different discs.
Testing was carried out at room temperature (72F).
SERIES
NUMBER SCORING BURST PRESSURE
In the above examples, the rupture disc material was moved relative to the source of the laser beam and under the "scoring", the relative movement in inches per minute is given. Test A is a standard where the rupture disc material was not treated; test B utilized a movement of 3 inches per minute and test C a movement of 2 inches per minute, all along a predetermined scoring pattern out-line. In effect, the slower the movement the greater the dwell time of the laser beam and consequently the greater the depth of the score made in the material of the disc.
* = Trade Mark ~3~
As will be seen, Erom the results given above, the rup-ture disc of test B had a burst pressure of 1,000 psig versus that of test C a burst pressure oE 875 psig where the latter was subjected to a greater duration of the laser beam.
This invention relates to a method of manufacturing metal rupture discs; more particularly, -this invention relates to an improved method of crea-ting lines of weak-ness or score lines in metal rupture discs.
In the prior art, rupture discs are normally pro-vided with weakened lines - i.e. the lines which rup-ture, by mechanical means. Typically, the material forming the weakened lines will be made by a blade pres-sing or scoring the metal. There are several disadvan-tages to this known type of process which basically in-volve the difficulty of obtaining constantly reproduc-ible results for given rupture pressures; also, such conventional techniques are quite expensive and result in a fairly costly product.
A more recent proposal is that disclosed in Canadian Patent 1,088,285 wherein rupture discs are pro-vided with a line of weakness by using a corrosive fluid to create scores in the metal. This technique is stated to provide improved results and may be more economical than the conventional techniques.
The present invention provides a further alterna-tive for creating a line of weakness, and according to this invention, the method of providing a line of weak-ness in a rupture disc comprises providing a metal sec-tion of a desired configuration, exposing preselected areas of said metal disc to a laser beam to create a displacement of metal in said section or to provide a weakened metal section.
In greater detail of the present invention, appli-cant has found that improved results can be obtained by forming the lines of weakness in a rupture disc using a laser beam, in which the laser is of a type wherein either a given depth of metal is removed by the action of the laser beam or alternately, the laser beam is eff-ective to alter the properties of the metal and create a line of weakness in the metal.
9~
~4~SO
The present invention is appllcable to various types of rupture discs such as -those well known in the art and used for the purpose of rup-turing under pre-determined pressure limits. Typically, such rupture discs may be the so-called conven-tional tension discs or a reverse buckling compression loaded disc.
One advantage of the present invention is that the rupture disc configuratlon can be initially formed and then subjected to the action of a laser beam or al-ter-nately, a laser beam can be used to create a line of weakness in sheet metal which can then be formed into a rupture disc.
A typical rupture disc normally has several lines of weakness and accordingly, conventional patterns forming the lines of weakness can be created using the method of the present invention.
With the method of the present invention, the use of a laser beam for creating the lines of weakness as noted above, may be one of two different types - a first type being where the heat generated by the laser beam on the surface of the material is such that metal is dis-placed from the material to create a line of weakness in the form of a groove or the like. To this end, basic-ally the material is removed along a predetermined sec-tion from the substrate material to create the line of weakness, it being understood that such lines of weak-ness do not extend through to the opposed surface of the substrate material.
The type of laser used for this invention may be any so-called "hot laser" which produces a light beam using a high temperature for the purpose of creating the line of weakness. Typically, the type of laser equip-ment may be any suitable laser equipment known to those skilled in the laser art for this purpose although pre-ferred equipment is that known as an ND Yag laser, which is a bottom end laser, or a C02 laser.
~3~
In an al-ternate embodiment, -the laser may be used so that the beam generated by the laser device creates a line of stress ~ i.e. a weakened line, in the rnaterial without displacing or removing any of the material. In this way, a rupture disc will not have any score lines on it per se but will be rupturable at a prede-termined pressure depending on the amount of stress created in the material. In turn, this will depend on the actual material used for the rupture disc and this may be var-ied according to the pressure rupture characteristics desired in the rupture disc. In one embodiment, accord-ing to the present invention, the method can initially form the rupture disc into its desired configura-tion, and then subject the resulting contoured product to the action of a laser beam. Thus, pre-formed rupture discs can be employed which are produced by conventional tech-niques in terms of their contours and configurations.
Substantially more uniform rupture characteristics can be obtained using the techniques of the present inven-tion, and as such, the resulting rupture discs provide a higher degree of reliability for rupturing at a given pres-sure. In addition, the present invention also provides an economical alternative method to conventional knife-blade scoring techniques relying on mechanical methods, or electro deposition methods.
In carrying out the method of the present invention, the weakened lines may be created in any rupture disc on either one or both sides of the rupture disc, as may be required for any given purpose. Thus, in some cases, it is desirable to provide a weakened line(s) in the concave or convex side only but in other cases, it may be desir-able to provide such weakened lines in both sides of the disc.
The rupture discs which are used for the method of the present invention can be made out of any suitable conventional material as is well known to those skilled ~a3~ 0 in the art; typically these are various types of metal-lic materials and more speciEically, are metallic alloys.
In using the method to create the lines of weakness, either the laser device can be movably mounted to rotate or traverse about a laser disc or disc blank which is otherwise mounted in a fixed manner or alterna-tely, the rupture disc or disc blank may be mounted for movement about a fixed laser beam. Suitable devices for rnovement of the laser or of the rupture disc or blank are known and can be used for this purpose; such devices will create a path of movement corresponding to a pre-deter-mined design or pattern to provide the desired line of weakness or stress in the rupture disc. Normally, sev-eral lines of weakness are provided in a given pattern eg. typically such lines may radiate from a central area of the rupture disc outwardly towards the periphery of the disc - other patterns are employed and it will be evident to those skilled in the art which pattern can be employed for any given purpose.
As rupture disc can be designed to rupture at dif-ferent pressures, which in turn partially depends on the type of metallic substance used to form the rupture disc, the laser treatment can be varied and create lines of weakness of different characteristics to create diff-erent bursting characteristics. For example, applicant has found that laser power variations using the ND Yag laser device with power settings of under 10 Joules can suffice for creating different types of lines of weak-ness.
130~
E _MPLE'S
A plurality of sheet me-tal discs were formed from "Inconel 600*" ma-terial of a thickness of 10,000's of an inch, into flat sea-ted rupture discs, each having a dia-meter of 2 inches. Using an ND Yag laser, each of the pre-formed rupture discs were laser scored with a conven-tional score pattern using a constant power level to form a series of scored tension-type rupture cliscs. The discs were then tested to determine the burst pressure, by sec-uring the individual rupture discs into a set-up in a test jig. Pressure was applied to the individual rupture discs using a variable pressure source; in the following table, the results given are for burst pressure of diff-erent series (A-C) of pre-formed discs, each series of discs being formed as described herein by laser treatment Each series of rupture discs was found, during test-ing, to successfully rupture along the pre-determined score lines created by the laser treatment, with the burst pressures being noted for the different discs.
Testing was carried out at room temperature (72F).
SERIES
NUMBER SCORING BURST PRESSURE
In the above examples, the rupture disc material was moved relative to the source of the laser beam and under the "scoring", the relative movement in inches per minute is given. Test A is a standard where the rupture disc material was not treated; test B utilized a movement of 3 inches per minute and test C a movement of 2 inches per minute, all along a predetermined scoring pattern out-line. In effect, the slower the movement the greater the dwell time of the laser beam and consequently the greater the depth of the score made in the material of the disc.
* = Trade Mark ~3~
As will be seen, Erom the results given above, the rup-ture disc of test B had a burst pressure of 1,000 psig versus that of test C a burst pressure oE 875 psig where the latter was subjected to a greater duration of the laser beam.
Claims (20)
1. A method of forming a score line for a rupture disc comprising providing a rupture disc surface of a metal-lic nature, and creating a weakened line of resistance in said metallic material by subjecting said metallic mater-ial to the action of a laser beam.
2. A method, as defined in Claim 1, wherein said rup-ture disc comprises a pre-formed rupture disc.
3. A method as defined in Claim 1, wherein said rupture disc comprises a rupture disc blank.
4. A method as defined in Claim 1, wherein said laser beam creates a score line in the surface of said metal-lic material.
5. A method as defined in Claim 1, wherein said laser beam creates a line of stress in the surface of said metallic material.
6. A method as defined in Claim 1, 2 or 3, wherein said laser is a ND Yag laser or a CO2 laser.
7. A method as defined in Claim 4 or 5, wherein said laser is a ND Yag laser or a CO2 laser.
8. A method as defined in Claim 1, 2 or 3, where a weakened line of resistance is created on a concave side of a rupture disc.
9. A method as defined in Claim 4 or 5, where a weak-ened line of resistance is created on a concave side of a rupture disc.
10. A method as defined in Claim 1, 2 or 3, where a weakened line of resistance is created on a convex side of a rupture disc.
11. A metallic rupture disc having a weakened line of resistance in said metallic material formed by the action of a laser beam.
12. The rupture disc as defined in Claim 11, wherein said rupture disc comprises a pre-formed rupture disc.
13. The rupture disc as defined in Claim 11, wherein said rupture disc comprises a rupture disc blank.
14. The rupture disc as defined in Claim 11, wherein a score line in the surface of said metallic material has been provided by a laser beam.
15. The rupture disc as defined in Claim 11, wherein a line of stress in the surface of said metallic material is created by a laser beam.
16. The rupture disc as defined in Claim 11, 12 or 13, wherein said laser is a ND Yag laser or a CO2 laser.
17. The rupture disc as defined in Claim 14 or 15, wherein said laser is a ND Yag laser or a CO2 laser.
18. A method as defined in Claim 11, 12 or 13, where the rupture disc has a weakened line of resistance on a con-cave side.
19. The rupture disc as defined in Claim 14 or 15, where the rupture disc has a weakened line of resistance cre-ated on a concave side.
20. The rupture disc as defined in Claim 11, 12 or 13, where the rupture disc has a weakened line of resistance created on a convex side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 545584 CA1304650C (en) | 1987-08-27 | 1987-08-27 | Method of manufacturing metal rupture discs |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 545584 CA1304650C (en) | 1987-08-27 | 1987-08-27 | Method of manufacturing metal rupture discs |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1304650C true CA1304650C (en) | 1992-07-07 |
Family
ID=4136353
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 545584 Expired - Lifetime CA1304650C (en) | 1987-08-27 | 1987-08-27 | Method of manufacturing metal rupture discs |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1304650C (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100006547A1 (en) * | 2005-04-01 | 2010-01-14 | Fike Corporation | Reverse acting rupture disc with laser-defined electropolished line of weakness and method of forming the line of weakness |
| EP2164674A1 (en) | 2007-06-18 | 2010-03-24 | Donadon Safety Discs and Devices S.R.L. | Method for production of safety /rupture discs having pre-calculated breaking threshold |
| WO2014141307A1 (en) | 2013-03-12 | 2014-09-18 | Donadon Safety Discs And Devices S.R.L. | Safety discs |
| EP2875270A1 (en) | 2012-07-18 | 2015-05-27 | Fike Corporation | Rupture disc having laser-defined reversal initiation and deformation control features |
-
1987
- 1987-08-27 CA CA 545584 patent/CA1304650C/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100006547A1 (en) * | 2005-04-01 | 2010-01-14 | Fike Corporation | Reverse acting rupture disc with laser-defined electropolished line of weakness and method of forming the line of weakness |
| US8414788B2 (en) * | 2005-04-01 | 2013-04-09 | Fike Corporation | Reverse acting rupture disc with laser-defined electropolished line of weakness and method of forming the line of weakness |
| EP2164674A1 (en) | 2007-06-18 | 2010-03-24 | Donadon Safety Discs and Devices S.R.L. | Method for production of safety /rupture discs having pre-calculated breaking threshold |
| EP2875270A1 (en) | 2012-07-18 | 2015-05-27 | Fike Corporation | Rupture disc having laser-defined reversal initiation and deformation control features |
| WO2014141307A1 (en) | 2013-03-12 | 2014-09-18 | Donadon Safety Discs And Devices S.R.L. | Safety discs |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed | ||
| MKLA | Lapsed |
Effective date: 19950107 |