| 摘要 |
A vacuum container has a vessel and an installed air extraction device covering the vessel. The installed air extraction device has a cap, an air extraction device disposed in the cap, and an air inlet valve passing through a center of the cap. The cap has an inner cover, an outer cover, and a hollow interior defined between the inner cover and the outer cover. An inner sleeve extends downward from the center portion of the outer cover. A spring encloses the middle portion of the air inlet valve. Another spring encloses the inner sleeve.
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