US2924351A

US2924351A - Spaced wall insulated storage container

Info

Publication number: US2924351A
Application number: US604744A
Authority: US
Inventors: Hawk Gale Frederick; George S Kiester
Original assignee: Aro Equipment Corp
Current assignee: Aro Equipment Corp
Priority date: 1956-08-17
Filing date: 1956-08-17
Publication date: 1960-02-09
Anticipated expiration: 1977-02-09

Description

Feb. 9, 1960 G. F. HAWK ETAL 2,924,351

SPAOED WALL INSULATED STORAGE CONTAINER Filed Aug. 17, 1956 2 Sheets-Sheet EL ATTORNEYS.

Feb. 9, 1960 G. F. HAWK EPA!- 2,924,351

SPACED WALL INSULATED STORAGE CONTAINER Filed Aug. 1'7, 1956 2 Sheets-Sheet 2 lNVENTORS ATTORNEYS.

United States Patent SPACED WALL INSULATED STORAGE CONTAlNER Gale Frederick Hawk and George S. Kiester, Bryan, Ohio, assignors to The Arc Equipment Corporation,

Bryan, Ohio, a corporation of Ohio Application August 17, 1956, Serial No. $4,744

3 Claims. (Cl. 220-15) This invention relates generally to improvements in container suspension systems and more particularly to improvements in suspension systems for thermally insulated containers of the type adapted to store liquid oxygen and the like.

The requirements for containers of the type adapted to hold and store low temperature materials are relatively stringent. For example, in containers for converter systems utilizing liquid oxygensuch as may be found in apparatus used as a source of breathing oxygen in aircraft designed for high altitude flight-resistance to heat loss should be as high as is practically obtainable. Further, the containers should be relatively sturdy with high resistance to vibration, shock and other mechanical disturbances. Still further, such containers advantageously should be relatively light weight, compact, efiicient, capable of holding a vacuum and economical to manufacture and use. Liquid oxygen containers of the prior art have not proved entirely satisfactory in meeting these requirements, and consequently there has existed a need for a new type of liquid oxygen container.

It is a general object of this invention to provide an improved container and, in particular, an improved container for holding and storing liquid oxygen and the like.

his another object of this invention to provide an improved vacuum container which has high resistance to heat loss and therefore is capable of storing liquid oxygen for substantial periods of time without undue vaporization.

It is still another object of this invention to provide an improved liquid oxygen container which is characterized by its efiiciency, light weight and high resistance to injury from vibration, shock and similar mechanical disturbances.

These and other objects are realized in accordance with the features embodied in specific illustrative embodiments of this invention in which an inner shell suitable for use with liquid oxygen and the like is suspended within an outer shell with a practical minimum of mechanical contact therebetween, and with the space be tween the two shells capable of being evacuated to a relatively high degree. Advantageously, the inner shell is in the form of a sphere to provide minimum surface area for a given volume. Manifestly this results in providing minimum force on the internal surface of the inner shell for a given gas pressure therewithin. The outer or protective shell advantageously is also in the form of a sphere, but is of larger radius than the container such that the inner shell is completely enclosed by the outer The inner and outer shells, hereinafter referred shell. to as the inner and outer spheres, respectively, are maintained spaced from each other by means of a novel beam suspension system which minimizes mechanical contact, and hence heat transfer, between the two spheres.

In accordance with one preferred embodiment of the invention the outer sphere is formed by joining two hemispheres after the inner sphere is dimensionally balanced therein. A band of channel cross section and of 2,924,351 Patented Feb. 9, 1960 cross section, are secured to the band at equally spaced points on the inner circumferential edges: of the band. Each suspension beam is secured transverse to the band, i.e., extending laterally of the inner and outer sphere, and is curved so as to be parallel to the spheres. A pair of spokes is associated with each beam; the inner end of each spoke is fastened to one end of the beam and the outer end of each spoke is fastened to a fitting on the surface of the inner sphere. The spokes are adapted to be fixed in tension after the inner sphere is centered within the outer sphere to maintain the desired dimensional balance between the inner and outer spheres. In this manner the outer sphere, the band, and the arcuate suspension beams all are maintained in spaced relation from the inner sphere the latter being suspended in tension at six points only, namely, the outer ends of each of the spokes. This novel construction is not only substantially free of any eifective heat loss but additionally is highly resistant to vibration and other mechanical disturbances.

In accordance with another preferred embodiment of the invention, the outer shell comprises two spherical segments, each less than a hemisphere and each welded to opposite circumferential edges of a band constituting the central Zone of the outer sphere. As in the first described embodiment three arcuate suspension beams are secured at equally spaced points to the band extending laterally of the inner and outer sphere. One pair of spokes is associated with each arcuate suspension beam and is adapted to be fastened to fittings on the surface of the inner sphere for maintaining the latter in dimensional balance at six points within the outer sphere.

The above and other features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of this invention, however, its advantages and specific objects attained with its use, reference is had to the accompanying drawing and descriptive matter in which is shown and described several illustrative embodiments of the invention.

In the drawing:

Figure 1 is a side elevation partially broken away of one embodiment of a liquid oxygen container embodying the suspension system of the present invention;

Figure 2 is a top plan view of the inner sphere of the container of Figure 1, taken substantially on line 2-2 thereof;

Figure 3 is a perspective view with the band partially broken away showing the arcuate suspension beam in accordance with the invention;

Figure 4 is a view taken substantially on line 4-4 of Figure 2 showing the spoke and fitting construction;

Figure 4A shows an alternative construction for the spoke and fitting; and

Figure 5 is a partial cross section illustrating the construction of another embodiment of the invention.

Referring now to the drawing, the specific illustrative embodiment shown in Figures 1 through 4A thereof comprises a thermally insulated container 10 having an outer sphere 12 and an inner sphere 14. Inner sphere 14 is of smaller radial dimension than outer sphere 12 and is adapted to be supported within the outer sphere with.

a minimum of physical contact therebetween.

Inner sphere 14 is suitable for holding and storing low temperature materials such as liquid oxygen which may be supplied to the inner sphere through an inlet conduit 16 and removed from the inner sphere through an outlet conduit 18. In the particular embodiment of the invention shown in Figure 1 conduits 16 and 18 are connected in parallel to a single pipe 20 extending through outer shell 12 and into inner shell 14. Conduit 16 advantageously may be connected to a filler valve and conduit 18 may be connected to a liquid check valve, such as' are included in oxygen supply systems.

The liquid contents of inner sphere 14 may be indicated by a suitable gauge connected to

electrical terminals

22 and 24 extending through outer shell 12 and connected by

conductors

26 and 28, respectively, to a probe within the inner shell. A conduit 32 is provided on outer shell 12 and is connected by piping 30 to the upper portion of inner shell 14. This permits desired pressures to be built up inside inner shell 14 to enable the container to function properly with suitable oxygen using equipment such as oxygen masks and the like with which the container is utilized.

It will be appreciated that since liquid oxygen vaporizes at a temperature of 183 C., it is necessary that a maximum degree of thermal insulation be maintained between the inner and outer spheres. This is attained in accordance with the invention by means of a novel suspension system comprising three arcuate suspension beams 36 fixed at 120 degree spacings to a band 34 welded to the inner circumference of outer sphere 12. Band 34 extends substantially around the inner circumference. of the outer sphere with only a relatively small gap between its ends. As seen most clearly in Figures 1 and 3, band 34 is of channel cross section and is positioned with its flanges facing inwardly towards the inner sphere. It is a feature of this invention that the lateral curvature of band 34, i.e., the curvature from one flange of the band to the other flange, be greater than the lateral curvature of the adjacent portion of sphere 12. The longitudinal curvature of band 34, i.e., the curvature from one end of the band to the other, conforms to the curvature of the inner surface of the outer sphere. Thus, when the band 34 is welded to the inner surface of sphere 12, the weld defines substantially a single line contact between band 34 and sphere 12. This is clearly shown, for example, in Figure 1 wherein the single line contact between band 34 and sphere 12 is indicated along the wheel line 62.

Three arcuate suspension beams 36 are attached at equally spaced points to band 34. Each suspension beam 36 is of channel cross section and is welded by means of

lugs

38 and 40 on opposite flanges thereof to band 34. Alternatively each suspension beam 36 may be formed with extension flanges extending outwardly from the beam in lieu of

lugs

38 and 40. In this embodiment, the beam extension flanges would be welded to band 34 to secure the beam thereto. The center of curvature of each suspension beam 36 is approximately the same as the centers of curvature of the inner and outer shells so that when the suspension beam is welded at right angles to band 34, the suspension beam is positioned intermediate and in parallel noncontacting relation with the inner and outer shells.

Each suspension beam 36 has at one end thereof an apertured flange 42 and at the other end thereof an apertured flange 46. A collar 50 extends outwardly from the inner face of flange 42 and a collar 52 extends outwardly from the inner face of flange 46. An elongated spoke 54 having a flared neck 56 at one end thereof is positioned through collar 50 and apertured flange 46 such that the collar engages the flared neck to provide a stop for the spoke.

In the embodiment of the invention shown in Figure 4, the other end of spoke 54 also is formed with a flared neck 58. The spoke is dimensionally balanced by drawing tubing 60 into a fitting 66 which advantageously is welded to the outer surface of inner sphere 14. This creates a tension on spoke 54 by virtue of the action of O-ring 68 in tubing 69 on spoke neck 58. After balance is made tubing 60 is welded to fitting 66.

Alternatively, as shown in the embodiment of Figure 4A, tubular member 60a is provided with an interior thread and the other end of spoke 54 is externally threaded to enable the spoke to be adjusted as desired. After the necessary adjustment has been made, the enlarged end of tubular member 60a, abutting fitting 66 is' welded to the fitting to fix the spoke firmly in position.

Fitting 66 advantageously is welded to the outer surface of inner sphere 14 in both embodiments. It can now be seen that inner sphere 14 is supported by spokes 54 positioned in tension at six points on its outer surface-three points are spaced 120 apart on one half of inner sphere 14 and three points are spaced 120 apart on the other half of sphere 14. When the desired dimensional balance has been obtained each spoke is fixed in position by swaging collar 52 on flared neck 56of the spoke to draw the spoke tight in assembly. After the suspension adjustment, collar 52 is welded to fitting 46 to provide additional rigidity to the inner sphere suspension.

When the above described operation is completed the two hemispheres comprising outer sphere 12 are welded together as designated at 62 in Figure 1. The space between the inner and outer spheres then is evacuated to provide additional thermal insulation for inner sphere 14 through a pinch 011, shown covered by cap 64.

In another preferred embodiment of the invention, as shown in Figure 5, the outer sphere may comprise the spherical segments 70 and 72, each smaller than a hemisphere. A band 74 of channel cross section forms the central zone of the outer sphere. Advantageously band 74 is placed with its flanges facing outwardly, that is, away from the inner sphere and the circumferential edges of spherical segments 70 and 72 are welded to the ends of the flanges of band 74 such that the ends of the band are flush with the spherical segments.

It will be appreciated that the construction illustrated in Figure 5 gives rise to several important advantages. Thus, the center band 74, being of channel cross section, provides a means for mounting the container by the use of straps and the like, in lieu of welded brackets, such as mounting brackets 48 shown in the embodiment of Figure 1. This serves to enhance the structural efiiciency of the container since every time a bracket is welded thereto, the chances of introducing leakage due to a faulty weld or induced stresses are increased.

Additionally, the use of the three piece outer sphere construction of Figure 5 permits the use of the center band 74 as the structural member for the support of the inner sphere. This allows the shell thickness of the two spherical segments 70 and 72 to be minimized as these segments need not be constructed as structural members. The resultant savings in weight and cost inherent in the construction of Figure 5 thus are evident. A plurality of arcuate suspension beams 76, similar in construction to previously described arcuate suspension beams 36, are connected to band 74. Advantageously three suspension beams 76 are aflixed to band 74 at equally spaced points on the inner face of the band. Each suspension beam 76 is secured to band 74 by means of a stud 80 extending through suspension beam 76 and band 74 in tight clamping relation thereto. As in the embodiment of Figures 1 through 4 a pair of apertured flanges is provided at the ends of each suspension beam 76 for connection to spokes in the manner .described above.

One alternative construction in which stud 80 is eliminated, comprises forming suspension beam 76 with extended flanges which are adapted to be mated and welded to central band 74. Another alternative construction in accordance with the invention comprises the forming of suspension beams 76 as integral parts of central band 74. Thus in this embodiment, the beams and band are integrally formed, such as in a one piece stamping which is fashioned into a circle and finally welded with the beams at right angles to the spherical segments of the outer sphere.

It will be understood by those skilled in the art that band 74 may be welded to spherical segments 70 and 72 with its flanges facing inwardly toward the inner sphere. This is an alternative embodiment which has been found to provide high advantageous results.

To facilitate the welding operations it is contemplated that the inner and outer spheres may be formed of stainless steel as the latter material is impervious to the diffusion of gases therethrough. It further is contemplated that to enhance the thermal insulation characteristics of the novel container the outer surface of inner sphere and the inner surface of outer sphere will each be plated as with copper, gold and the like, to increase their reflection qualities.

It will be understood by those skilled in the art that modifications may be made in the construction and arrangement of the parts of the above described suspension system liquid oxygen converter without departing from the real purpose and spirit of the invention and that it is intended to cover by the appended claims any modified forms of structures, circuits or use of equivalents which reasonably may be included within their scope.

What is claimed is:

l. A thermally insulated container adapted for holding liquid oxygen and the like comprising an outer sphere, an inner sphere of radius smaller than that of said outer sphere and adapted to be completely enclosed by said outer sphere and means for maintaining said innet sphere in dimensional balance within said outer sphere whereby said inner sphere is substantially parallel to said outer sphere at all points thereof, said means comprising an arcuate band circumferentially atfixed to the inner surface of said outer sphere, said band being formed of channel cross section with the legs of the channel extending inwardly and the web of said channel having a lateral curvature greater than the curvature of said outer sphere whereby the junction of said band and said outer sphere defines a line contact, a plurality of laterally extending arcuate suspension beams afiixed to said band at equally spaced apart points therearound, each of said arcuate suspension beams having a curvature concentric to that of said inner and outer spheres such that each beam is supported in parallel noncontacting relation with the inner and outer spheres, a plurality of fittings aflixed to the outer surface of said inner sphere, each fitting being spaced a fixed distance from an end of an arcuate suspension beam, at spoke connected between each end of an arcuate suspension beam and one of said fittings, means for aflixing each of said spokes in tension between its fitting and arcuate suspension beam to maintain the inner sphere in dimensional balance within the outer sphere and means for enabling the space between said inner and outer spheres to be evacuated to provide a vacuum therebetween.

2. A thermally insulated container adapted for holding liquid oxygen and the like comprising an outer sphere, an inner sphere of radius smaller than that of said outer sphere and adapted to be completely enclosed by said outer sphere, an arcuate band aflixed to the inner surface of said outer sphere and extending circumferentially therearound, a plurality of laterally extending arcuate suspension beams afiixed to said band, said beams having a curvature concentric to that of said inner and outer spheres such that each beam is supported in parallel noncontacting relation with the inner and outer spheres, a fitting afi'ixed to the outer surface of said inner sphere at a fixed distance from each end of each of said arcuate suspension beams, 21 spoke connected between each end of an arcuate suspension beam and one of said fittings and adapted to be placed in tension therebetween to maintain the inner sphere in dimensional balance Within the outer sphere.

3. A thermally insulated container comprising an outer sphere, an inner sphere of radius smaller than that of said outer sphere and adapted to be completely enclosed by said outer sphere and means for maintaining said inner sphere in parallel spaced relation within said outer sphere comprising a first arcuate member circumferentially afiixed to the inner surface of said outer sphere at least three second arcuate members transversely afiixed to said first arcuate member at equally spaced apart points therearound, each of said second arcuate members having a curvature concentric to that of said inner and outer spheres such that each beam is supported in parallel noncontacting relation with the inner and outer spheres, at least six fittings aflixed to the outer surface of said inner sphere, each fitting being spaced from one end of one of said second arcuate members and a spoke connected between each end of each of said second members and one of said fittings and adapted to be placed in tension therebetween for maintaining the inner sphere in dimensional balance with the outer sphere.

References Cited in the file of this patent UNITED STATES PATENTS 2,467,428 Hansen et a1. Apr. 19, 1949 2,577,171 Wiggins et al. Dec. 4, 1951 2,706,575 Soherr Apr. 19, 1955