| 摘要 |
PROBLEM TO BE SOLVED: To provide a very low temperature freezer having a sealing mechanism wherein even though the freezer is operated over a long period of time sealing property is prevented from being deteriorated and being lost. SOLUTION: There are disposed an inner ring 5 radially inwardly of outer rings 2, 3 overlapped axially and an inclined endless coiled spring 9 further inside the inner ring 5. In a region of a predetermined amount of compression of the inclination coiled spring 9 radial reaction force is kept substantially unchanged, so that even though outer surfaces of the outer rings 2, 3 wear to expand inner diameters of the outer rings 2, 3, and hence enlarge the inclination coiled spring 9 to reduce the degree of compression of the inclination coiled spring 9, there can be kept substantially unchanged spring force for energyzing the inner ring 5 to the outside radially by the inclination coiled spring 9. As a result, inner surfaces of the outer rings 2, 3 and a cylinder 13 are kept in a close contact and hence sealing property of a sealing mechanism is secured stably.
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