CA2151862A1 - Method of manufacturing pressure vessel liners - Google Patents
Method of manufacturing pressure vessel linersInfo
- Publication number
- CA2151862A1 CA2151862A1 CA002151862A CA2151862A CA2151862A1 CA 2151862 A1 CA2151862 A1 CA 2151862A1 CA 002151862 A CA002151862 A CA 002151862A CA 2151862 A CA2151862 A CA 2151862A CA 2151862 A1 CA2151862 A1 CA 2151862A1
- Authority
- CA
- Canada
- Prior art keywords
- blank
- rollers
- forming
- wall thickness
- pressure
- 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.)
- Abandoned
Links
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 7
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 20
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 20
- 230000003247 decreasing effect Effects 0.000 claims 2
- 230000035515 penetration Effects 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 14
- 210000003739 neck Anatomy 0.000 description 18
- 239000000463 material Substances 0.000 description 7
- 230000008569 process Effects 0.000 description 5
- 238000003860 storage Methods 0.000 description 5
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 239000003345 natural gas Substances 0.000 description 2
- 238000009987 spinning Methods 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 235000000396 iron Nutrition 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D51/00—Making hollow objects
- B21D51/16—Making hollow objects characterised by the use of the objects
- B21D51/18—Making hollow objects characterised by the use of the objects vessels, e.g. tubs, vats, tanks, sinks, or the like
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
- B21D22/14—Spinning
- B21D22/16—Spinning over shaping mandrels or formers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D51/00—Making hollow objects
- B21D51/16—Making hollow objects characterised by the use of the objects
- B21D51/24—Making hollow objects characterised by the use of the objects high-pressure containers, e.g. boilers, bottles
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2203/00—Vessel construction, in particular walls or details thereof
- F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
- F17C2203/0634—Materials for walls or layers thereof
- F17C2203/0636—Metals
- F17C2203/0646—Aluminium
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
- F17C2223/01—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the phase
- F17C2223/0107—Single phase
- F17C2223/0123—Single phase gaseous, e.g. CNG, GNC
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
- F17C2223/03—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the pressure level
- F17C2223/036—Very high pressure (>80 bar)
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
- Shaping Metal By Deep-Drawing, Or The Like (AREA)
Abstract
Previously, aluminum pressure vessels have been formed from drawn tubes of uniform thickness. The invention provides a method of manufacturing aluminum pressure vessels directly from extruded tubes, the vessels having at least one threaded neck, comprising:
a) using a flow forming method to provide a blank having greater wall thickness adjacent the ends thereof than in the centre; b) forming hemispherical ends on said blank;
and c) forming an outwardly extended threaded neck.
a) using a flow forming method to provide a blank having greater wall thickness adjacent the ends thereof than in the centre; b) forming hemispherical ends on said blank;
and c) forming an outwardly extended threaded neck.
Description
2151~62 This invention relates to the manufacture of an impermeable, tubular, seamless aluminum pressure vessels for containing fluids and gases under pressure, such as natural gas or propane storage tanks for vehicles. In particular, the invention relates to a method of manufacture of aluminum pressure vessel lines having a hemispherical end with a threaded neck.
For applications such as storage of natural gas in natural gas-fuelled vehicles, it is necessary to provide a storage tank which can sustain a high number of pressurizations and depressurizations without weakening, and at the same time is of minimum weight. One solution has been to provide an inner liner of a metal such as aluminum which is overwrapped by a layer of glass fibre and polyester resin. The inner liner provides impermeability to the stored fluid, but is relatively expansible and alone would not withstand the internal pressures.
According to current methods, the aluminum vessel is produced by extrusion, drawing and forming. Initially a tube is formed by extruding the pliable heated aluminum through a die. The tube is permitted to cool and is then drawn through a second die of reduced diameter, to reduce the diameter of the tube and provide a cylindrical tube of-strengthened aluminum. The tube is cut to the desired length, leaving enough material to form the hemispherical ends and neck. The rounded ends of the vessel are then formed by heating the tube to about 450 degrees C. and rotating the tube in a chuck while engaging the end of the tube with a roller which applies pressure repeatedly following an arc from the end of the tube towards the centre to form the hemispherical end and then longitudinally to form an external neck.
In almost all cases, a threaded neck, external or internal, is required for connecting fittings to the vessel. This means that a greater thickness of material is required in the area of the neck. For certain applications, such as vehicle fuel storage, pressure vessels having internal, rather than external necks are desired. Such vessels have certain advantages, such as requiring less storage space. To provide a threaded neck requires considerable thickness in the vicinity of the neck. Using conventional means for forming the vessel requires that this thickness be consistent throughout the tube, prior to forming the neck, which causes the thickness of the material to be greater than is necessary in the central cylindrical area of the 25 vessel. This adds to the weight and expense of materials for the vessel.
There is therefore a need for a method of manufacturing pressure vessels in which increased thickness of the vessel is provided in one or both ends 5to accommodate a threaded neck.
It is therefore a principle object of the present invention to provide a thin-walled and hence lightweight aluminum liner directly from extruded aluminum pipe or tube without requiring the necessity for "extruded" pipe 10to be "drawn" in an independent process step.
It is a further object of the present invention to flow form, from an extruded aluminum pipe, a pressure vessel liner which has a reduced wall thickness of up to 80% of the cylindrical wall compared to currently 15produced pressure vessels, with increased wall thickness at each end.
The invention provides a method of manufacturing from an extruded aluminum tube of initial constant thickness, an impermeable tubular seamless pressure 20vessel liner of minimal constant cylindrical wall thickness throughout a central section thereof, the liner having a tapering inner wall, thickening towards its cylindrical extremities leading into a hemispherical section with a continuing thickness of that section to 25terminate in an end of maximum thickness suitable for 2151~62 accepting internally threaded valvings.
In drawings which illustrate a preferred embodiment of the invention:
Figure 1 is a cross-sectional view of a pressure 5vessel having a threaded neck;
Figure 2 is a cross-sectional view of a tube for forming into a pressure vessel having a threaded neck according to the invention;
Figures 3 through 6, show schematically, the forming 10stages which produce the tube according to Figure 2; and Figure 7 shows schematically, an intermediate stage prior to forming hemispherical ends.
Figure 1 illustrates in cross-section an aluminum pressure vessel 10 having a threaded neck 12 and 15hollow interior 11. Cylindrical walls 14 of the vessel will desirably be approximately .125 inches in thickness. Internal neck 12 has a threaded aperture 16 which is typically 1.25 inches in diameter to accept standard threaded fittings. The thickness of the wall 20of the vessel in the vicinity of the internal neck 12 will be approximately .250 inches to provide a neck of sufficient thickness to support a thread.
Figure 2 illustrates the preferred configuration according to the invention of the extruded aluminum tube 2520 prior to formation into the pressure vessel as shown in Figure 1. It has hollow cylindrical interior 21 and wall 22 in the central region having the desired thickness of about .125 inches. The wall of the vessel adjacent the ends at 24, however, has an increased thickness of about .250 inches. While the inner surface 25 of the vessel forms a smooth cylinder, the outer surface of the wall forms an outwardly tapering shoulder 23 between regions 22 and 24. A tube formed in this manner permits the vessel shown in Fig. 1 to be formed according to standard "spinning" methods, described hereafter, providing sufficient thickness in the vicinity of the internal neck without excess thickness in the cylindrical walls.
The configuration of aluminum tubing blank shown in Figure 2 is formed generally as follows. It is formed following a method referred to as "flow forming" which utilizes an existing machine disclosed in United States Patent No. 3,517,534 entitled "Apparatus For Working Tubes" issued June 30, 1970 to assignee Koehring Co. and naming Kenneth A. Schaefer and John A. Werner as inventors. This machine ("The Werner Machine") utilizes three or four axially spaced rollers to apply large radial and axial deforming pressures to a tubular metal blank chucked at one end to a rotating mandrel. The working of the rollers is determined by a gauge which 21518-&2 co-operates with the hydraulic cylinder acting on the rollers. The axial movement of the rollers is also carefully controlled. The machines of this type as disclosed are useful for producing metal cylinders having an extremely smooth finish and surfaces which are axially straight and circumferentially round. It has been discovered that this method is useful for producing aluminum pressure vessels according to this invention.
Referring specifically to Figures 3 through 6, which are schematic representations of the steps required to produce the tubular blank according to Figure 2, the process starts utilizing an extruded aluminum pipe 25, which in the preferred embodiment has an outside diameter of 12 inches, cut to a predetermined length.
The wall thickness of this pipe 25 may vary .200 inches to .500 inches. The tube 25 is then fatigue tested using conventional methods to avoid early failure in a finished product.
The pipe 25 is mounted on the mandrel 26 (Figure 6) of a flow forming machine, of the type referenced above.
With the mandrel 26 spinning in the direction of arrow 27, at a predetermined and preset rpm, for example, 400 feet per minute, which is dependent on the outside diameter of the pipe, rollers 28 (only one shown) are led on to the pipe at a predetermined position 29, 21518~2 (Figure 4).
It is noted at this point, that the "predetermined position" 29 that initiates the commencement of the forming step, is selected by a proximity switch (not shown) on the carriage 31, which indicates the point where the rollers 28 are pressed into the pipe material.
Figure 4 shows the rollers 28 being pushed into the material of the pipe 25 by hydraulic pressure in the direction arrow 30. At the same time, the roller carriage 31 is initiated to move along the pipe 25 at a predetermined speed in the direction of arrow 32.
By controlling the hydraulic pressure being applied through rollers 28 and the speed in direction 32, a longitudinal tapered section 24 is formed (Figure 5).
With a mandrel having a predetermined feed per revolution of 15 to 30 inches per minute, a taper of to 2 inches in length can be formed. When the roller carriage 31 arrives at a predetermined position at the other end of the pipe 25, the rollers 28 are slowly disengaged, see Figure 5, and a further elongate tapered section 24 is formed. The taper being reverse to that previously described.
Using this procedure it will be appreciated that what is produced is a pipe with a substantially thin centre section, tapered at both ends, those ends being at the original wall thickness of the extruded pipe.
This flow forming process "irons" the extruded pipe into a much closer tolerance than the original pipe, as least as regards roundness, straightness, and wall thickness is concerned. At the same time, the tensile strength of the material is improved, ie: the compressive stress of the cold working process increased the yield and tensile strength of the aluminum.
The next step in the process, which is to spin form each end 33 (Figure 1) of the tube 20, into substantially closed, dome-shaped ends 34 with outwardly extending necks 12, the latter being finally threaded for valve or the like attachments.
During this end closing process or cycle, the external tapered section is first spun into a straight length (Figure 7), prior to completing the final radius of the dome. With this procedure there is an increased wall thickness in the ends of the liner before the true radius of the dome 34 starts.
As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.
For applications such as storage of natural gas in natural gas-fuelled vehicles, it is necessary to provide a storage tank which can sustain a high number of pressurizations and depressurizations without weakening, and at the same time is of minimum weight. One solution has been to provide an inner liner of a metal such as aluminum which is overwrapped by a layer of glass fibre and polyester resin. The inner liner provides impermeability to the stored fluid, but is relatively expansible and alone would not withstand the internal pressures.
According to current methods, the aluminum vessel is produced by extrusion, drawing and forming. Initially a tube is formed by extruding the pliable heated aluminum through a die. The tube is permitted to cool and is then drawn through a second die of reduced diameter, to reduce the diameter of the tube and provide a cylindrical tube of-strengthened aluminum. The tube is cut to the desired length, leaving enough material to form the hemispherical ends and neck. The rounded ends of the vessel are then formed by heating the tube to about 450 degrees C. and rotating the tube in a chuck while engaging the end of the tube with a roller which applies pressure repeatedly following an arc from the end of the tube towards the centre to form the hemispherical end and then longitudinally to form an external neck.
In almost all cases, a threaded neck, external or internal, is required for connecting fittings to the vessel. This means that a greater thickness of material is required in the area of the neck. For certain applications, such as vehicle fuel storage, pressure vessels having internal, rather than external necks are desired. Such vessels have certain advantages, such as requiring less storage space. To provide a threaded neck requires considerable thickness in the vicinity of the neck. Using conventional means for forming the vessel requires that this thickness be consistent throughout the tube, prior to forming the neck, which causes the thickness of the material to be greater than is necessary in the central cylindrical area of the 25 vessel. This adds to the weight and expense of materials for the vessel.
There is therefore a need for a method of manufacturing pressure vessels in which increased thickness of the vessel is provided in one or both ends 5to accommodate a threaded neck.
It is therefore a principle object of the present invention to provide a thin-walled and hence lightweight aluminum liner directly from extruded aluminum pipe or tube without requiring the necessity for "extruded" pipe 10to be "drawn" in an independent process step.
It is a further object of the present invention to flow form, from an extruded aluminum pipe, a pressure vessel liner which has a reduced wall thickness of up to 80% of the cylindrical wall compared to currently 15produced pressure vessels, with increased wall thickness at each end.
The invention provides a method of manufacturing from an extruded aluminum tube of initial constant thickness, an impermeable tubular seamless pressure 20vessel liner of minimal constant cylindrical wall thickness throughout a central section thereof, the liner having a tapering inner wall, thickening towards its cylindrical extremities leading into a hemispherical section with a continuing thickness of that section to 25terminate in an end of maximum thickness suitable for 2151~62 accepting internally threaded valvings.
In drawings which illustrate a preferred embodiment of the invention:
Figure 1 is a cross-sectional view of a pressure 5vessel having a threaded neck;
Figure 2 is a cross-sectional view of a tube for forming into a pressure vessel having a threaded neck according to the invention;
Figures 3 through 6, show schematically, the forming 10stages which produce the tube according to Figure 2; and Figure 7 shows schematically, an intermediate stage prior to forming hemispherical ends.
Figure 1 illustrates in cross-section an aluminum pressure vessel 10 having a threaded neck 12 and 15hollow interior 11. Cylindrical walls 14 of the vessel will desirably be approximately .125 inches in thickness. Internal neck 12 has a threaded aperture 16 which is typically 1.25 inches in diameter to accept standard threaded fittings. The thickness of the wall 20of the vessel in the vicinity of the internal neck 12 will be approximately .250 inches to provide a neck of sufficient thickness to support a thread.
Figure 2 illustrates the preferred configuration according to the invention of the extruded aluminum tube 2520 prior to formation into the pressure vessel as shown in Figure 1. It has hollow cylindrical interior 21 and wall 22 in the central region having the desired thickness of about .125 inches. The wall of the vessel adjacent the ends at 24, however, has an increased thickness of about .250 inches. While the inner surface 25 of the vessel forms a smooth cylinder, the outer surface of the wall forms an outwardly tapering shoulder 23 between regions 22 and 24. A tube formed in this manner permits the vessel shown in Fig. 1 to be formed according to standard "spinning" methods, described hereafter, providing sufficient thickness in the vicinity of the internal neck without excess thickness in the cylindrical walls.
The configuration of aluminum tubing blank shown in Figure 2 is formed generally as follows. It is formed following a method referred to as "flow forming" which utilizes an existing machine disclosed in United States Patent No. 3,517,534 entitled "Apparatus For Working Tubes" issued June 30, 1970 to assignee Koehring Co. and naming Kenneth A. Schaefer and John A. Werner as inventors. This machine ("The Werner Machine") utilizes three or four axially spaced rollers to apply large radial and axial deforming pressures to a tubular metal blank chucked at one end to a rotating mandrel. The working of the rollers is determined by a gauge which 21518-&2 co-operates with the hydraulic cylinder acting on the rollers. The axial movement of the rollers is also carefully controlled. The machines of this type as disclosed are useful for producing metal cylinders having an extremely smooth finish and surfaces which are axially straight and circumferentially round. It has been discovered that this method is useful for producing aluminum pressure vessels according to this invention.
Referring specifically to Figures 3 through 6, which are schematic representations of the steps required to produce the tubular blank according to Figure 2, the process starts utilizing an extruded aluminum pipe 25, which in the preferred embodiment has an outside diameter of 12 inches, cut to a predetermined length.
The wall thickness of this pipe 25 may vary .200 inches to .500 inches. The tube 25 is then fatigue tested using conventional methods to avoid early failure in a finished product.
The pipe 25 is mounted on the mandrel 26 (Figure 6) of a flow forming machine, of the type referenced above.
With the mandrel 26 spinning in the direction of arrow 27, at a predetermined and preset rpm, for example, 400 feet per minute, which is dependent on the outside diameter of the pipe, rollers 28 (only one shown) are led on to the pipe at a predetermined position 29, 21518~2 (Figure 4).
It is noted at this point, that the "predetermined position" 29 that initiates the commencement of the forming step, is selected by a proximity switch (not shown) on the carriage 31, which indicates the point where the rollers 28 are pressed into the pipe material.
Figure 4 shows the rollers 28 being pushed into the material of the pipe 25 by hydraulic pressure in the direction arrow 30. At the same time, the roller carriage 31 is initiated to move along the pipe 25 at a predetermined speed in the direction of arrow 32.
By controlling the hydraulic pressure being applied through rollers 28 and the speed in direction 32, a longitudinal tapered section 24 is formed (Figure 5).
With a mandrel having a predetermined feed per revolution of 15 to 30 inches per minute, a taper of to 2 inches in length can be formed. When the roller carriage 31 arrives at a predetermined position at the other end of the pipe 25, the rollers 28 are slowly disengaged, see Figure 5, and a further elongate tapered section 24 is formed. The taper being reverse to that previously described.
Using this procedure it will be appreciated that what is produced is a pipe with a substantially thin centre section, tapered at both ends, those ends being at the original wall thickness of the extruded pipe.
This flow forming process "irons" the extruded pipe into a much closer tolerance than the original pipe, as least as regards roundness, straightness, and wall thickness is concerned. At the same time, the tensile strength of the material is improved, ie: the compressive stress of the cold working process increased the yield and tensile strength of the aluminum.
The next step in the process, which is to spin form each end 33 (Figure 1) of the tube 20, into substantially closed, dome-shaped ends 34 with outwardly extending necks 12, the latter being finally threaded for valve or the like attachments.
During this end closing process or cycle, the external tapered section is first spun into a straight length (Figure 7), prior to completing the final radius of the dome. With this procedure there is an increased wall thickness in the ends of the liner before the true radius of the dome 34 starts.
As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of manufacturing impermeable tubular aluminum pressure vessel liners having at least one threaded neck, comprising:
a) Providing a hollow cylindrical extruded aluminum blank having axially straight inner and outer surfaces and substantially constant wall thickness throughout;
b) Mounting said block coaxially on a mandrel which is rotated about a longitudinal axis;
c) Reducing the wall thickness of a central section of said blank by initially applying radially inwardly directed pressure to the surface of said blank at a first predetermined position adjacent a first end of said blank, by one or more rollers, which rotate about an axis parallel to the axis of said blank;
d) Moving said rollers axially along said blank while increasing the pressure to the surface of the blank, thereby forming a first longitudinally extending section of the blank with gradually tapering and decreasing wall thickness;
e) Moving said rollers axially along said centre section of said blank while controlling the depth of radial penetration of said rollers to a second predetermined position adjacent the second end of said blank;
f) Decreasing the pressure to the surface of said blank by said rollers while continually moving said rollers axially along said blank to form a second longitudinally extending section with gradually tapering and increasing wall thickness;
g) Forming hemispherical ends on said blank by spin forming each end of said blank such that each tapered section is planar with said central section and completing, as by spin forming, the ends of said blanks into substantially closed outwardly extending neck portions;
h) Forming threads in each said neck portion for the attachment of ancillary fittings.
a) Providing a hollow cylindrical extruded aluminum blank having axially straight inner and outer surfaces and substantially constant wall thickness throughout;
b) Mounting said block coaxially on a mandrel which is rotated about a longitudinal axis;
c) Reducing the wall thickness of a central section of said blank by initially applying radially inwardly directed pressure to the surface of said blank at a first predetermined position adjacent a first end of said blank, by one or more rollers, which rotate about an axis parallel to the axis of said blank;
d) Moving said rollers axially along said blank while increasing the pressure to the surface of the blank, thereby forming a first longitudinally extending section of the blank with gradually tapering and decreasing wall thickness;
e) Moving said rollers axially along said centre section of said blank while controlling the depth of radial penetration of said rollers to a second predetermined position adjacent the second end of said blank;
f) Decreasing the pressure to the surface of said blank by said rollers while continually moving said rollers axially along said blank to form a second longitudinally extending section with gradually tapering and increasing wall thickness;
g) Forming hemispherical ends on said blank by spin forming each end of said blank such that each tapered section is planar with said central section and completing, as by spin forming, the ends of said blanks into substantially closed outwardly extending neck portions;
h) Forming threads in each said neck portion for the attachment of ancillary fittings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002151862A CA2151862A1 (en) | 1995-07-24 | 1995-07-24 | Method of manufacturing pressure vessel liners |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002151862A CA2151862A1 (en) | 1995-07-24 | 1995-07-24 | Method of manufacturing pressure vessel liners |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2151862A1 true CA2151862A1 (en) | 1997-01-25 |
Family
ID=4156048
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002151862A Abandoned CA2151862A1 (en) | 1995-07-24 | 1995-07-24 | Method of manufacturing pressure vessel liners |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2151862A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014140610A1 (en) | 2013-03-14 | 2014-09-18 | Luxfer Gas Cylinders Limited | Method of manufacturing pressure vessel liners |
| CN110640042A (en) * | 2019-09-25 | 2020-01-03 | 中材科技(成都)有限公司 | A kind of gas storage bottle processing method |
-
1995
- 1995-07-24 CA CA002151862A patent/CA2151862A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014140610A1 (en) | 2013-03-14 | 2014-09-18 | Luxfer Gas Cylinders Limited | Method of manufacturing pressure vessel liners |
| JP2016520430A (en) * | 2013-03-14 | 2016-07-14 | ラックスファー ガス シリンダーズ リミテッド | Manufacturing method of pressure vessel liner |
| CN110640042A (en) * | 2019-09-25 | 2020-01-03 | 中材科技(成都)有限公司 | A kind of gas storage bottle processing method |
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| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |
Effective date: 19990726 |