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Publication numberUS3889835 A
Publication typeGrant
Publication dateJun 17, 1975
Filing dateMay 10, 1974
Priority dateMay 10, 1974
Publication numberUS 3889835 A, US 3889835A, US-A-3889835, US3889835 A, US3889835A
InventorsRichard H Avant, Peter R Webster
Original AssigneeBernzomatic Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
One-piece pressure container
US 3889835 A
Abstract
A pressure container made of aluminum, for example, is disclosed and includes a generally cylindrical body and a self-standing integral bottom which has a downwardly extending peripheral skirt portion. The bottom of the container has an inside radius of about R1 and an exterior configuration which, in vertical cross-section along a diameter line includes:
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United States Patent [191 Avant et al.

[ 1 ONE-PIECE PRESSURE CONTAINER [75] Inventors: Richard H. Avant, Rochester; Peter R. Webster, Greece, both of NY.

[73] Assignee: BernzOmatic Corporation,

Rochester, NY.

[22] Filed: May 10,l974

21 Appl. No.: 468,962

[52] US. Cl. 220/3; 220/66; 220/70 [51] TM. CI. ..F17c 1/14; B65d l/16; B65d H42 [58] Field of Search 220/3, 66, 67, 70, 73, 220/74; 215/1 R, 1 C

[56] References Cited UNITED STATES PATENTS 79,692 7/1868 Scantlin et al. 220/70 7 651,884 6/1900 Platz 220/70 1,878,709 9/1932 Kerr..... 220/73 X 2,541,065 2/1951 Jabour 220/3 3,038,627 6/1962 Daley 220/3 3,115,281 12/1963 vSomme.... 220/70 X 3,279,640 10/1966 Dodson 220/67 X 3,409,167 11/1968 Blanchard... 220/66 3,434,626 3/1969 Kinslow, Jr. 220/66 FOREIGN PATENTS OR APPLICATIONS 11,593 7/1889 United Kingdom 220/70 432,718 8/1935 United Kingdom.... 220/3 1,344,861 10/1963 France 220/3 Sweden 220/70 June 17, 1975 Primary Examiner-William 1. Price 1 Assistant Examiner-Stephen Marcus I Attorney, Agent, or Firm-Burge ss, Dinklage Sprung [5 7] ABSTRACT A pressure container made of aluminum, for example, is disclosed and includes a generally cylindrical body and a self-standing integral bottom which has a down The thinnest portion of the bottom is in the upwardly curved portion and is not less than about 1.5, preferably 2 times the wall thickness of the cylindrical body.

8 Claims, 2 Drawing Figures portion PAIENTEDJUN 11 ms :19; 8 89,8 35

FIG. I.

PRIOR RT ONE-PIECE PRESSURE CONTAINER BACKGROUND This invention relates to a one-piece pressure container preferably made of aluminum which is especially suited for use as a fire extinguisher where the contents are under relatively high pressure. More particularly, this invention relates to a one-piece aluminum pressure container having an integral self-standing bottom which meets contemporary safety standards.

Impact extruded aluminum containers have been used for fire extinguishers and the like where the contents are under pressure. At first, such containers were formed with a domed bottom, and, if the container was to be self-standing, a separate plastic or metal bottom cap had to be attached over the domed bottom. It was then proposed to reverse the bottom of the container and impact extrude the container with an integral skirt portion. However, because of certain unique cold flow characteristics of aluminum under high impact, it was found that reversing the bottom to form a skirt portion resulted in the formation ofa concentric, unfused seam which reached depths as great as about 0.14 inch. This created an undesirable structural defect which resulted in the skirt portion falling off when the container was subjected to high impact such as by dropping a loaded or charged fire extinguisher onto a hard surface.

The present invention overcomes this structural problem and provides a self-standing integral bottom structure for aluminum pressure containers that can be formed as a part of the container by impact extrusion in one step. The pressure container of the invention is structurally sound and meets all requirements of Underwriters Laboratories, Inc. (UL) for fire extinguishers and the like.

SUMMARY The pressure container of the invention comprises a generally cylindrical body and a self-standing integral bottom having a peripheral skirt portion, said bottom having an inside radius of about R and an exterior configuration which, in vertical cross-section along a diameter line, includes:

i. a disc-like, circular central portion;

ii. a concentric upwardly curved portion contiguous with the central portion and having a radius of about 0.22 R;

iii. a concentric downwardly curved portion contiguous with the skirt portion and having a radius of about 0.19 R; and

iv. a generally flat concentric portion contiguous with and between the curved portions.

The thinnest portion of the bottom is in the upwardly curved portion and is not less than about 1.5, preferably about 2 times the wall thickness of the cylindrical body.

With a bottom structure as described, it is now possible to form a one-piece aluminum pressure container in one step having an integral bottom with a concentric seam no greater than about 0.03 to about 0.06 inch deep, preferably no greater than about 0.04 inch deep.

DESCRIPTION OF THE DRAWING The present invention will be more fully understood from the following description taken in conjunction with the accompanying drawing wherein:

FIG. 1 is a vertical cross-sectional view, partly broken away, along the longitudinal axis of the pressure container of the present invention; and

FIG. 2 is vertical cross-sectional view, partly broken away, of an integral bottom structure according to the prior art.

DESCRIPTION Referring now to the drawing and in particular FIG. 1, the pressure container of the invention which is preferably formed from aluminum is shown to include a generally cylindrical body 10 and a self-standing integral bottom which is generally identified by reference numeral 12. An otherwise conventional threaded neck portion 14 is formed at the upper portion of the container as shown. The upper or neck portion of the container can have any configuration, depending on the use intended for the container and the neck structure shown in the drawing is only for purposes of illustration and is not intended to be otherwise limiting.

The integral bottom 12 is shown to have an inside radius R and an exterior configuration which, in vertical cross-section along a diameter line includes, central portion 20 having a diameter d, upwardly curved portion 22 which is concentric with and contiguous to the central portion 20 and having a radius R equal to about 0.22 R, a concentric, downwardly curved portion 26 joined to or contiguous with the skirt portion 28 and having a radius R equal to about 0.19 R and a generally flat concentric portion 24 which is contiguous with and between the curved portions 22 and 26.

The thinnest portion of the bottom 12 is positioned or located in the upwardly curved portion 22 and is identified in the drawing by reference character e. The thickness e is not less than about 1.5, preferably 2 times the wall thickness f of the cylindrical body 10.

To prevent rocking and to insure upright stability of the container, the central portion 20 lies in a horizontal plane which is higher than the horizontal plane of the lower end of the skirt portion 28.

In a further preferred embodiment the central portion 20 has a diameter d as shown and the diameter of the central 20, together with the upwardly curved portion 22 is about 1.5 d. This is shown in the drawing by the diameter line c. The diameter of the central portion d, together with the upwardly curved portion 22 and the flat portion 24 is preferably about 2 d. This is shown in the drawing by diameter line a. The width b of the flat portion 24 will vary, depending on the size of the container, whereas the relationship between the radii R, R and R will remain fairly constant as described above.

The lower end of the skirt portion 28 is preferably curved and has a minimum radius R, which is equal to about 0.045 R.

FIG. 2 of the drawing depicts a concentric seam 18 which radiates from the curved portion 16 of the bottom of the prior art container. This seam 18 is formed due to certain unique cold flow characteristics of aluminum under high impact and reaches depths as great as about 0.14 inch. The bottom structure of the invention as shown in FIG. 1 practically eliminates this undesirable unfused seam 18 and provides a smooth transformation from the'central portion 20 up through the portion 22, across the portion 24, down through the portion 26 and finally down to the skirt 28. In practice it has been found that a certain residual seam or surface roughening will occur in the downwardly curved portion 26. However, this does not detract from the structural integrity of the container of'the invention" and it has been found that a concentric seam 30, as shown in FIG. 1 in the downwardly curved portion 26, can be tolerated with depths between about 0.03 to about 0.06 inch and preferably no greater than 0.04 inch deep.

When an aluminum slug is inserted into the cavity of an impact extrusion die, it is believed that a lower portion of the slug cold flows along the bottom of the die conforming to the configuration thereof, while an upper zone flows outwardly to the side of the die cavity. With a sharp radius such as shown by reference numeral 16 in FIG. 2, the aluminum in the lower zone is believed to flow over the radius 16 and into the downwardly extending skirt portion faster than aluminum flowing from the upper portion of the slug. This is thought to account for the undesirable formation of an unfused seam 18 which can cause the skirt portion to fall off upon impact. In the present invention, the upwardly curved portion 22 containing the minimum bottom thickness e is believed to function as a gate area for the cold flowing aluminum and the flat portion 24, following the upwardly curved portion 22, is believed to function as a pressure retard zone which compensates for the differences in cold flow characteristics of the aluminum. In other words, the flat portion 24 acts as a pressure retard zone in cooperation with the gate e, which cause the aluminum to cold flow at substantially the same rates and thereby form the downwardly curved portion 26 and the downwardly extending skirt portion 28 without the formation of an undesirable unfused seam 18, such as shown in FIG. 2 of the drawing.

What is claimed is:

1. Pressure container comprising a generally cylindrical body and a self-standing integral bottom having a peripheral skirt portion, said bottom having an inside radius of about R and an exterior configuration which,

in vertical cross-section along a diameter line, includes: i. a disc-like, circular central portion;

ii. a concentric upwardly curved portion contiguous with said central portion and having a radius of about 0.22 R;

iii. a concentric downwardly curved portion contiguous with the skirt portion and having a radius of about 0.19 R; and

iv. a generally flat concentric portion contiguous with and between the curved portions.

2. Pressure container of claim 1 wherein the thinnest portion of said bottom is in the upwardly curved portion and is not less than 1.5 times the wall thickness of the cylindrical body.

3. Pressure container of claim 1 wherein said central portion lies in a plane higher than the horizontal plane of the lower end of the skirt portion.

4. Pressure container of claim 1 wherein said central portion has a diameter d and the diameter of the central portion, together with the concentric upwardly curved portion is about 1.5 d.

5. Pressure container of claim 1 wherein said central portion has a diameter d and the diameter of said central portion, together with the concentric upwardly curved portion and the concentric generally flat portion is about 2 d.

6. Pressure container of claim 2 wherein said thinnest portion is not less than about 2 times the wall thickness of the cylindrical body.

7. Pressure container of claim 1 wherein the lower end of the skirt portion is curved and has a minimum radius of about 0.045 R.

8. Pressure container of claim 1 wherein said downwardly curved portion has a concentric circular seam with a depth in the range of about 0.03 to about 0.06

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US79692 *Jul 7, 1868 scantlin
US651884 *Feb 17, 1900Jun 19, 1900Hermann PlatzReceptacle for gases, &c., and process of manufacturing same.
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US2541065 *Dec 30, 1944Feb 13, 1951Specialties Dev CorpHigh-pressure container
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4402909 *Oct 28, 1981Sep 6, 1983Chemplex Industries, Inc.Vials for comminuting and blending samples for spectrochemical analysis
US4609118 *Feb 13, 1984Sep 2, 1986Simmel S.P.A.Convex type bottom with a bearing rim for bottles for industrial gases obtained by means of hot forging from a steel billet
US5598729 *Oct 26, 1994Feb 4, 1997Tandem Systems, Inc.System and method for constructing wall of a tube
US5845527 *Feb 3, 1997Dec 8, 1998Tandem Systems, Inc.System and method for constricting wall of a tube
US5992830 *Dec 15, 1997Nov 30, 1999Olin CorporationHigh pressure quartz glass bubbler
US6045125 *Aug 17, 1999Apr 4, 2000Olin CorporationHigh pressure quartz glass bubbler ampoule and assembly
US6212926Apr 21, 1999Apr 10, 2001Tandem Systems, Inc.Method for spin forming a tube
US6213325Nov 22, 1999Apr 10, 2001Crown Cork & Seal Technologies CorporationFooted container and base therefor
US6296471 *Aug 26, 1998Oct 2, 2001Crown Cork & Seal Technologies CorporationMold used to form a footed container and base therefor
DE3327171A1 *Jul 28, 1983Aug 30, 1984Simmel SpaFlasche fuer technische gase
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DE102005010281B3 *Mar 7, 2005Oct 5, 2006Rothenberger AgDruckgasquelle mit Brenngasfüllung
DE102005010282B3 *Mar 7, 2005Nov 2, 2006Rothenberger AgDruckgasquelle mit Brenngasfüllung
EP0117849A2 *Jan 30, 1984Sep 5, 1984Simmel Difesa S.R.L.Convex type bottom with a bearing rim for bottles for industrial gases obtained by means of hot forging from a steel billet and fixture for forming said bottom
EP1701085A2Feb 14, 2006Sep 13, 2006Rothenberger AGSource of pressure gas with combustion gas for manual operation
EP1701086A2Feb 14, 2006Sep 13, 2006Rothenberger AGSource of pressure gas with combustion gas for manual operation
WO1999030813A1 *Dec 14, 1998Jun 24, 1999Olin CorpHigh pressure quartz glass bubbler ampoule and assembly
Classifications
U.S. Classification220/581, 220/606
International ClassificationF17C1/14
Cooperative ClassificationF17C2203/0646, F17C2223/035, F17C2260/011, F17C2201/032, F17C1/14, F17C2203/0617, F17C2205/018, F17C2201/056, F17C2203/011, F17C2270/0754, F17C2201/0109, F17C2203/0658
European ClassificationF17C1/14
Legal Events
DateCodeEventDescription
Jan 23, 1984ASAssignment
Owner name: NEWELL COMPANIES, INC., A DE CORP.
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:BERNZ O MATIC CORPORATION A NY CORP;REEL/FRAME:004213/0173
Effective date: 19831220