Low Temperature Storage Vessel

Abstract

A low temperature storage vessel for storing receptacles containing perishables has a tray rotatable about a vertical axis, access to the tray being had through a laterally offset upper opening. The tray is supported for rotation on a vertical screw that bears on the upper end of an elongated vertical pivot. Manipulation of the screw raises and lowers the tray. In the lowered position, the tray rests on the container bottom for stability during transport. In the raised position, the tray is rotatable and can be raised above ice formations.

Description

The invention relates to a low temperature storage vessel, for storing perishables in a cryogenic liquid such as liquid nitrogen, more particularly for preserving biological products such as bovine semen for centers of artificial insemination.

Such low temperature storage vessels are well-known for storing perishable commodities in special receptacles, such as canisters, which are placed in the vessel.

Such a storage vessel, comprises an inner wall and an outer wall defining therebetween an insulation space under vacuum, an opening through the top part of the vessel affording access to the storage space, the opening being offset from the vertical axis of said vessel and the axis passing through that opening. A revolvable tray adapted for supporting receptacles such as canisters is disposed in the storage space, and a pivot integral with the bottom part of the inner wall extends vertically along the vessel axis in the storage space, up to about the opening. A sleeve fixedly attached to the tray is revolvably mounted around that pivot, the tray resting on the pivot at the upper portion of the sleeve, whereby the tray revolves around the pivot.

In the case of a storage vessel having the above structure, the revolvable tray with its load of canisters rests entirely on the axial pivot through the upper portion of the sleeve. This leads to the drawback that the tray, when loaded with many canisters, is generally heavy and the axial pivot, which is fixedly attached to the inner wall only at its narrow lower end, is very fragile. Therefore, during transportation of the storage vessel, the pivot encounters important flexural stresses which may distort it with respect to the vertical axis of said vessel, and which may even break it at its lower end.

The storage vessel according to the present invention eliminates these drawbacks. According to the invention, the storage vessel is further provided with means for vertically positioning the revolvable tray, especially in a lower position allowing the tray to rest entirely on the innerside of the bottom part of the thermally insulated wall and in upper positions allowing the tray to be spaced from the bottom of the wall and to revolve.

In this way it is possible to transport the storage vessel with full safety, by placing the tray with its load of canisters in the lower position in which the tray rests on the bottom part of the thermally-insulated wall.

In addition, these positioning means bring about the following further advantages:

1. By placing the tray in an upper position spaced from the bottom part of the storage vessel, it is possible to prevent the tray from rubbing against the solid deposits, such as ice, which necessarily accumulate in the bottom part of the storage space, during storage use of the vessel. Therefore, whatever the thickness of these deposits, it is possible to raise the tray and prevent it from becoming blocked by ice accumulation and to drive the tray around the axial pivot. Perfect working of the tray is in this manner always ensured.

2. By placing the tray in an upper position, it is possible to have easier access, through a trap in the bottom part of the tray, to the space between the tray and the bottom part of the thermally insulated wall of the vessel, when removal of solid deposits or cleaning is desired.

The invention will now be more fully understood by reference to the accompanying drawings in which:

FIG. 1 is a diametral section of a low temperature storage vessel according to the invention; and

FIG. 2 is an enlarged fragmentary section of the central part of the vessel shown in FIG. 1.

As shown in FIG. 1, a low temperature storage vessel in accordance with the invention comprises a thermally insulated wall 1 defining a low temperature storage space 2, symmetrical with respect to its vertical axis 3. Wall 1 comprises an outer stainless steel wall 4 and an inner stainless steel wall 5 defining therebetween an insulation space 6 which may contain an insulating material and which has been evacuated through vacuum connection stem 18. Insulation space 6 is exposed to an adsorbent 19 in a recess defined by the inner wall 5 at the bottom thereof, communicating with space 6 through the perforations of a metal sheet 20 enclosing the adsorbent. Adsorbent 19 ensures the preservation of the vacuum during the storage vessel life. A safety vacuum device 21 is disposed at the top part of the outer wall 4. An opening 7 extends through the thermally insulated wall 1, at its top, and allows access to the storage space 2. The axis 8 of opening 7 is offset from the vertical axis 3 of the storage vessel, and axis 3 passes through opening 7. A closure 9 having a peripherally protruding shoulder 26 is made of insulating material such as expanded plastic and closes the eccentric opening 7 during storage use of the vessel. Closure 9 fits loosely in the opening 7, to define therewith an annular passage for avoiding any pressure rise within the storage vessel.

The bottom part of the inner wall 5 bears an axial tubular pivot 11 extending vertically along the storage vessel axis 3 in the storage space 2 up to about opening 7. The pivot 11 is integral with the inner wall 5, and therefore with the insulated wall 1.

A revolvable tray 12 is provided for placing therein receptacles such as canisters 21. This tray is fixedly attached to a cylindrical sleeve 13, revolvably mounted around the pivot 11. An upper plug 14 in the sleeve 13 rests upon an upper plug 15 in the pivot 11, through a screw 16, the function of which will be explained hereinafter.

A bearing 17, disposed at about 1/3 of the height of pivot 11, ensures correct centering of the sleeve 13 on the pivot 11. The neck 10 of the opening 7 alone suspends the inner wall 5, with the pivot 11, the plate 12 and its load of canisters 21, from the outer wall 4.

During storage, the stopper 9 closes opening 7, and the tray 12 with its load of canisters 21 is immersed in liquid nitrogen 27, thereby to cool and preserve the biological substance contained by the receptacles 21. When access to any canister 21 is wished, stopper 9 is revolved. Then the tray 12 is rotated by a removable driving rod 25 (shown in dotted lines in FIG. 2), which is fitted on the upper plug 14 of the sleeve 13. Canisters 21, covering the whole of the tray 12, thus all pass beneath the eccentric opening 7, until the chosen canister can be removed through that opening.

The storage vessel also has means for positioning vertically the tray 12 in the storage space 2 in a lower position shown in FIG. 1 with dotted lines, wherein the plate rests entirely on the inner side of the bottom part of the wall 1 or inner wall 5 through flanges 28, and in upper positions, shown for example in full lines in FIG. 1, wherein tray 12 is spaced from that bottom part. The positioning means comprise the manually adjusting screw 16, fitted through the upper plug 14 of the sleeve 13, and bearing on the upper plug 15 of the axial pivot 11. To that end, the adjusting screw 16 is received in a threaded bore 29 of the upper plug 14.

When it is desired to transport the storage vessel by means of the casters 22, disposed at the bottom of the storage vessel, the screw 16 is manually unscrewed by access thereto through the opening 7, so as to make the tray 12 rest in a lower position, entirely on the bottom part of the insulated wall 1. When the storage vessel is to be in use and stationary, the screw 16 is manually screwed, so as to raise the tray 12 to an upper position, supported entirely on the pivot 11, through the upper portion of the sleeve 13, in which position the tray 12 is revolvable around the pivot 11.

A cleaning trap 24 is disposed in the bottom plate 23 of the tray 12. It allows access to the space between plate 23 and the bottom part of inner wall 5, wherein ice and other solid deposits can accumulate. When cleaning is desired, easier access to this space is had by lifting the tray 12 by means of the adjusting screw 16.

Claims

Having described our invention, we claim:

1. A low temperature storage vessel for storing receptacles containing perishables, comprising a thermally insulated wall defining a low temperature storage space, an opening through the top part of said wall giving access to said storage space, said opening being laterally offset from the center of the vessel, a pivot upstanding from the bottom of the vessel, a revolvable tray in said storage space for supporting said receptacles, a vertical sleeve surrounding and revolvably mounted about said pivot, said tray being fixedly secured to said sleeve, means for vertically positioning said tray in said storage space, comprising a threaded plug disposed in the upper end of said sleeve, a vertical manually adjustable screw extending through said threaded plug and bearing at its lower end on the upper end of said pivot, whereby by manipulation of the upper end of said screw said tray can be positioned in a lower position in which said tray rests entirely on the bottom of the vessel and upper positions in which said tray is spaced from the bottom of the vessel and is revolvable about said pivot.

2. A low temperature storage vessel for storing receptacles containing perishables, comprising a thermally insulated wall defining a low temperature storage space, an opening through the top part of said wall giving access to said storage space, said opening being laterally offset from the center of the vessel, a pivot upstanding from the bottom of the vessel and extending a major portion of the height of the vessel, a vertical sleeve surrounding and revolvably mounted on said pivot, a revolvable tray in said storage space for supporting said receptacles and fixedly secured to said sleeve, and means acting between the upper end of said sleeve and the upper end of said pivot and accessible through said opening for manual adjustment to move said sleeve vertically relative to said pivot thereby to position said tray selectively in a lower position in which the tray rests entirely on the bottom of the vessel or in upper positions in which said tray is spaced from the bottom of the vessel and is revolvable about said pivot.

3. A vessel as claimed in claim 2, said means comprising screw means passing through the upper end of said sleeve and bearing on the upper end of said pivot and having an exposed upper end for manual adjustment thereof.