摘要 |
A device for cleaning opposing surfaces (13, 14) of concentric columns (11, 12) is formed from a strip of material (20) configured as a spiral having inside and outside edges (21, 22) such that each edge (21, 22) forms a helix. The device (10) is utilized by introducing it between the concentric columns (11, 12). The strip (20) inside edge (21) abuts the opposing surface (13) of the inner column (11), and the outside edge (22) abuts the opposing surface (23) of the outside column (12). The device (10) is forced to travel along the lengths of the columns (11, 12) by an hydraulic fluid downflow thereby scraping deposits from the opposing surfaces (13, 14).
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