| 摘要 |
<p>PURPOSE:To provide a cryogenic temperature container of such stability that there is no vacuum leak into an inner cylinder, by making the bottom plate of the inner cylinder from a fiber-reinforced plastic of quasi-isotropy and making the outside diameter of the bottom plate befoe assembly larger than the inside diameter of the inner cylinder. CONSTITUTION:The directions of fibers of a glass fabric for making the bottom plate 3 of an inner cylinder 2 cross at 45 deg. with each other. The bottom plate 3 is made of a fiber-reinforced plastic wherein such glass fabrics are alternately stratified. The inside diameter diameter D1 of the inner cylinder 2 is smaller than the outside diameter D0 of the bottom plate 3 before they are coupled to each other. The difference between the inside diameter D1 and the outside diameter D0 is set to correspond to the expansion of the inner cylinder 2 which is caused when the air in a heat insulator between an outer cylinder and the inner cylinder and the bottom plate 3 is removed. The bottom plate 3 is press-fitted and bonded in the inner cylinder 2 so that they are coupled to each other. The bottom plate 3 undergoes a uniform thermal contraction in all direction. The thermal contraction is held down as a whole, so that vacuum leak is prevented. A plastic reinforced by short fibers oriented at random may also be press-formed as the bottom plate 3.</p> |
