| 摘要 |
A moisture damage protection system for an article display case of the type which uses an air pump to inject high pressure air through an air line into a base portion of a transparent, liquid filled tube or column to form bubbles which rise through the liquid in the column is disclosed. The protection system prevents liquid in the column from backing up through the air line into the air pump when the pump is de-energized. A hollow pipe, which may be in the form of one of several support pipes for article support plates surrounding the column, is provided in which the air line from an air outlet port of the pump is inserted. The air line extends upwardly through the hollow pipe to a level above the level of the liquid in the tube, then loops back downwardly through the hollow pipe and out of a base portion of the hollow pipe into an air inlet port in a base portion of the column which is in communication with the liquid in the column. When the pump is de-energized, liquid from the column can not back-up into the air line far enough upwardly through the hollow pipe to reach the loop at the upper end of the air line, whereby liquid from the column can not back-up into the pump when it is de-energized.
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