U.S. patent number 3,613,934 [Application Number 04/788,799] was granted by the patent office on 1971-10-19 for inner container support structure for dewar vessel.
This patent grant is currently assigned to Cryogenic Engineering Company. Invention is credited to Kenneth R. Leonard.
United States Patent |
3,613,934 |
Leonard |
October 19, 1971 |
INNER CONTAINER SUPPORT STRUCTURE FOR DEWAR VESSEL
Abstract
A dewar container has one end of a bellows supported above the
outer wall and the other end connected to a closure plate affixed
to the top of the inner container's neck tube so that the inner
storage container is pendularly suspended from the outer wall by
the neck tube and bellows. A cylindrical support surrounds the
bellows and extends downwardly from the closure plate to a support
adapter on the outer wall. The cylindrical support is free to move
up and down with respect to the outer wall's support adapter as the
inner container undergoes its pendular motion, but a tab and slot
arrangement prevents more than a predetermined amount of both
upward and rotational motion of the support with respect to the
outer wall, while engagement of the support with the adapter limits
downward motion of the inner container with respect to the dewar's
outer wall. The inner containers of dewar vessels are frequently
supported within the vessel's outer walls by means of a relatively
long neck tube affixed to the inner container. In order to prevent
undue heat leak from the dewar's surroundings into the container
interior through the neck tube, however, the neck tubes are
frequently made of a thin low heat conductive material. But because
of the thin neck tube walls, it has been necessary to provide
auxiliary supports to prevent the type of relative motion between
the inner container and the dewar's outer wall that would damage
the neck tube. Alternatively, if it is desired to eliminate
auxiliary supports between the inner container and the outer walls,
it has been necessary to make the vessle's neck tube sufficiently
strong to withstand both the tension and bending stresses to which
the neck tube is subjected as well as torsional stresses which
occur from time to time. This type of solution, however, has
resulted in an increase in the overall heat conductivity of the
thusly strengthened neck tubes. One solution to the above problems
has been to suspend the neck tube and thereby the inner container
from the outer wall by a bellows arrangement. In this manner, a
certain amount of flexibility has been provided between the
vessel's outer and inner walls so as to permit the vessel's neck to
be somewhat thinner. In thusly structured devices, however, the
combined load of the fluid in the inner container and the forces
due to the space between the vessel's walls having been evacuated,
has compressed the bellows to the point where it is not
sufficiently flexible to accomplish its intended purpose.
Similarly, a bellows that is made sufficiently strong to avoid such
loads is not sufficiently flexible to begin with. Consequently, it
is an object of this invention to provide a support structure for
the inner container of a dewar vessel wherein the inner container
is pendularly suspended within the vessel's outer walls by a
flexible bellows, but wherein the bellows is not required to be so
heavy as to either lose its intended flexibility or be so thin that
it will be compressed to the point where it loses its flexibility.
An additional drawback of the previous types of bellows suspension
systems is that the bellows are not well suited for withstanding
torsional loads caused by relative rotation between the vessel's
inner and outer walls. Consequently, it is another object of this
invention to provide a flexible bellows suspension system for a
dewar's inner container wherein the bellows is substantially
isolated from torsional loads. In accordance with the principles of
the invention a bellows is connected between the top of the inner
container's neck tube and the vessel's outer walls so that the
inner storage container is pendularly suspended and adapted for
both pendular and vertical axial motion with respect to the dewar's
outer walls. A motion limiting compression support is affixed to
the top of the neck tube. This member is adapted to move upwardly a
predetermined amount but, engages a support adapter on the dewar's
outer wall after the bellows is contracted to the point where the
inner container undergoes a certain predetermined amount of
downward motion relative to the vessel's outer wall. In this
manner, the inner container and the neck tube are permitted to
undergo pendular motion without the neck tube being subjected to
bending stresses so that the neck tube can be made thinner than
otherwise required. In addition, a tab is either located on the
outer wall's support adapter so as to engage a slot in the
compression support; or the tab is located on the compression
support so as to engage a slotted element on the vessels outer
wall. In either case, the tab and slot structure prevents the
bellows from being subjected to torsional stresses so that the
bellows can be made thinner and thereby more flexible. The
foregoing and other objects, features, and advantages of the
invention will be apparent from the more particular description of
preferred embodiments thereof, as illustrated in the accompanying
drawings, wherein the same reference numerals refer to the same
parts throughout the various views. The drawings are not
necessarily intended to be to scale, but rather are presented so as
to illustrate the principles of the invention in clear form.
Inventors: |
Leonard; Kenneth R. (Boulder,
CO) |
Assignee: |
Cryogenic Engineering Company
(Denver, CO)
|
Family
ID: |
25145594 |
Appl.
No.: |
04/788,799 |
Filed: |
January 3, 1969 |
Current U.S.
Class: |
220/560.1;
220/918 |
Current CPC
Class: |
F17C
3/08 (20130101); F17C 2203/0629 (20130101); F17C
2205/0305 (20130101); F17C 2270/0509 (20130101); F17C
2203/018 (20130101); F17C 2203/01 (20130101); Y10S
220/918 (20130101); F17C 2201/0104 (20130101); F17C
2201/032 (20130101); F17C 2203/0391 (20130101) |
Current International
Class: |
F17C
3/00 (20060101); F17C 3/08 (20060101); B65d
025/00 () |
Field of
Search: |
;220/9A,14,9E,15 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Leclair; Joseph R.
Assistant Examiner: Garrett; James R.
Claims
The embodiments of the invention in which an exclusive property or
privilege are claimed are defined as follows:
1. A neck suspension for a vacuum insulated double walled storage
vessel having an inner storage container thereof suspended from an
outer wall by a low thermal-conductivity neck tube, the suspension
for said neck tube comprising:
a bellows affixed to said outer wall;
connecting means for connecting said bellows to said neck tube so
that said inner storage container is pendularly suspended from said
outer wall by said neck tube and bellows, and adapted for pendular
and vertical axial motion with respect to said outer wall;
limit means spaced apart from said inner storage container and
disposed externally of said bellows for limiting both upward and
downward vertical motion of said inner container with respect to
said outer wall to a predetermined amount; and
additional rotation limiting means disposed externally of said
connecting means to limit rotational motion of said inner storage
container with respect to said outer wall.
2. A neck suspension for a double walled storage vessel having an
inner storage container thereof suspended from an outer wall by a
low thermal-conductivity neck tube, the suspension for said neck
tube comprising:
a bellows affixed to said outer wall;
connecting means for connecting said bellows to said neck tube so
that said inner storage container is pendularly suspended from said
outer wall by said neck tube and bellows, and adapted for pendular
and vertical axial motion with respect to said outer wall;
limit means for limiting both upward and downward vertical motion
of said inner container with respect to said outer wall to a
predetermined amount; and
wherein said limit means includes a support affixed to said
connecting means and extending toward said outer wall, but movable
with respect to said outer wall from an upper position to a lower
position when said support is in contact with said outer wall
whereby said inner container has a predetermined minimum lower
position with respect to the outer wall.
3. The apparatus of claim 2 including a rotation limiting means for
limiting rotational motion of said inner storage container with
respect to said outer wall.
4. The apparatus of claim 2 including an upper motion limiting
means operative in combination with said support means to limit
upward motion of said inner storage container with respect to said
outer wall.
5. The apparatus of claim 4 including a rotation limiting means for
limiting rotation of said inner storage container with respect to
said outer wall.
6. The apparatus of claim 4 wherein said upper motion limiting
means is affixed to said outer wall and engageable with said
support when said support is in a predetermined upper position.
7. The apparatus of claim 6 including a rotation limiting means for
limiting rotation of said inner storage container with respect to
said outer wall.
8. The apparatus of claim 6 wherein said support has a slot therein
said upper motion limiting means having an end thereof extending
into said slot so as to limit upward motion of said support by
engagement of said end with the lower end of said slot and to limit
rotational motion of said support and thereby said inner container
by engagement of a side of said limiting means with a side of said
slot.
9. The apparatus of claim 6 wherein said means for limiting upward
motion of said support includes a slotted means affixed to said
outer wall and a means affixed to said support and extending
therefrom into the slot on said slotted means whereby upward motion
of said support is limited by engagement of said means extending
therefrom with said slot; and rotational motion of said support is
limited by engagement of the sides of said extended means with the
sides of the slot.
10. A neck suspension for a double walled storage vessel having an
inner storage container thereof suspended from an outer wall by a
low thermal conductivity neck tube, the suspension for said neck
tube comprising:
a first collar affixed to the top of said neck tube and extending
outwardly therefrom;
a second collar affixed to said outer wall;
a bellows connected between said first collar and said second
collar so that said neck tube and thereby said inner container are
pendularly suspended within said outer wall by means of said
flexible bellows;
a support member surrounding said bellows and affixed at an upper
end to said first collar and extending downwardly toward said
second collar, said support member being adapted to move upwardly
and downwardly with said inner container, but limited in its
downward motion by engagement with said second collar so as to
correspondingly limit downward motion of said inner container with
respect to said outer wall.
11. The apparatus of claim 10 including an outwardly projecting arm
on said support member; and a slotted stanchion affixed to said
outer wall, said arm extending into said slotted stanchion so as to
have an upper surface thereof engageable with said slotted
stanchion upon a predetermined amount of upward motion of said
inner storage container with respect to said outer wall, and a side
surface thereof engageable with a side of said slotted stanchion
upon more than a predetermined amount of rotation of said inner
storage container with respect to said outer wall.
12. The apparatus of claim 10 an including an inwardly projecting
arm affixed to said outer wall; and a slot in said support member,
said arm extending into said slot and engageable with a lower
portion of said slot upon a predetermined amount of upward motion
of said inner storage container with respect to said outer wall,
and engageable with a side portion of said slot upon a
predetermined amount of rotation of said inner storage container
with respect to said outer wall.
Description
In the drawings:
FIG. 1 is a pictorial view of a dewar vessel of the type in which
this invention finds particular utility and illustrates one
embodiment of the invention's means for limiting the torsional
stresses that are transmitted to the bellows;
FIG. 2 is a fragmentary sectional view taken along the arc 2--2 in
FIG. 1;
FIG. 3 is a pictorial view of the neck of a dewar vessel employing
an alternative embodiment of the tab means for preventing torsional
stresses from being transmitted to the bellows;
In FIGS. 1 and 2, a conventional dewar vessel 10 has an outer wall
12 spaced from an inner container wall 14 by a vacuum space 16.
The vacuum space preferably contains one or another of a variety of
bulk insulation materials such as a laminated insulation or
suitable opacified powder. These matters, however, form no part of
the instant invention and will not be further discussed.
The inner container 14 is supported from the outer container 12 by
means of a low thermal conductivity neck tube 18 which is
preferably made of a fiberglass reinforced expoxy resin or
stainless steel and should have as thin a wall as possible
compatible with the strength required to support the inner
container 14 and its contents.
A support adapter or collar 20 is welded or otherwise suitably
connected in a gas tight manner to an extension 22 of the vessel's
outer wall 12. Similarly, an upper collar or closure plate 24 is
affixed at 26 by means of a gas tight seal about the outer
circumference of the low conductivity neck tube 18; and a flexible
bellows 28 is connected between flange 30 on the lower collar 20
and flange 32 on the upper collar 24. In this manner, the inner
container 14 is pendularly suspended from the dewar's outer wall 12
by means of the flexible bellows 28 so that the inner container is
free to undergo motion within the vacuum space 16.
A cylindrical support 36 is welded at 38 to the outer circumference
of the upper collar 24 which also functions as a closure plate for
the vacuum space 16. The cylindrical support has a plurality of
vertical slots 40 about its circumference and extends downwardly
about the bellows 28 so as to be slidably disposed about a shoulder
42 on the outer wall's support adapter 20. The cylindrical support,
therefore, is permitted to move upwardly or pivot back and forth
about its lower outside rim 44 as it follows motion of the upper
collar 24 which moves with the pendular or vertical motion of the
inner container. When the inner container moves a predetermined
distance downwardly with respect to the outer wall 12, however, the
lower surfaces 46 of the cylindrical support bear against the
shoulder 42 of the outer wall's support adapter 20 so as to
rigidify the connection between the vessel's inner and outer walls.
In this manner, the bellows 28 is permitted to have its walls
desirably thin so as to be sufficiently flexible when the neck tube
18 is normally loaded, but both the bellows 28 and the neck tube 18
are supported by the cylindrical support 36 when the neck tube is
subjected to high loads.
In the FIG. 1 and 2 embodiments, a plurality of bent tabs or pins
50 have their lower portions 52 welded to the outer circumference
of the support adapter 20, while their other ends 54 extend
inwardly through the vertical slots 40 on the cylindrical support
36. This structure permits the cylindrical support to move upwardly
or pivot until the lower surface 56 of one of the vertical slots 40
is brought into engagement with the lower surface 58 of the
corresponding tab 50. This structure, therefore, functions to limit
the upward motion of the inner storage container with respect to
the outer walls.
In addition, rotational motion of the clindrical support, and
thereby the inner container, is limited by one of the sides 60 of
one of the tabs 50 with a corresponding side 62 of one of the
vertical slots 40. Consequently, although the structure permits a
predetermined small amount of rotation to be transmitted to the
flexible bellows 28, the bellows is thusly isolated from large
torsional stresses of the type which would otherwise require a
substantially stronger bellows and neck structure.
The FIG. 3 embodiment of the invention is substantially the same as
that illustrated in FIGS. 1 and 2 except that a plurality of tabs
70 and slotted stanchions 72 are substituted for the first
embodiment's combination of tabs 50 and slots 40. In the FIG. 3
embodiment, the tabs 70 are affixed to the cylindrical support 36
and extend outwardly into slots 74 of the stanchions 70 which are
affixed at their lower ends 76 to the dewar's outer wall 12. In
this manner, the upward motion of the support cylinder 36 is
limited by engagement of one of the upper surfaces 78 with the
inner top portion 80 of a corresponding stanchion; and rotary
motion of the cylindrical support 36 is limited by engagement of a
side 82 of one of the tabs 70 with one of the inside surfaces 82 of
one of the stanchions 72. In all other respects, the second
embodiment's structure is substantially equivalent to that of the
first, and, hence, will not be further discussed. Those skilled in
the art, however, will appreciate that both embodiments provide a
structure whereby the inner container can be pendularly suspended
without requiring either an undesirably rigidified bellows or an
overly thick neck tube. Similarly, it will be appreciated that both
embodiments prevent substantial torsional stresses from being
transmitted to the bellows.
While the invention has been particularly shown and described with
reference to preferred embodiments thereof, it will be understood
by those skilled in the art that various changes in form and detail
may be made therein without departing from the spirit and scope of
the invention. For example, although the invention has been
described in connection with a dewar having a cylindrical neck, it
will be appreciated that the invention is equally applicable to
dewars having square necks or, in its broader aspects, to vessels
having the storage container's support structure located
substantially within the vessel's outer walls rather than extending
outwardly therefrom as has been illustrated.
* * * * *