| 摘要 |
A method of cleaning a vertically positioned filter element in p a filter tank for treating influent liquid, the filter element having a precoat layer of ion exchange resin or diatomaceous earth comprises draining the influent liquid from the filter tank until the level of the influent liquid is at least below the filter element, then passing a gas to a lower portion of the filter element and through the filter element in reverse flow to the normal operation of the filter element while simultaneously gradually admitting wash liquid to the filter tank and submerging the filter element in the wash liquid to form a gradually increasing vertical liquid-gas interface along the filter element to clean the filter element, and thereafter passing backwash liquid through the filter element in reverse flow to the normal operation of the filter element. The wash liquid may be water at 100-200 DEG F, alcohols, CCl4, detergent or soap solution. The filter elements may be nylon wound. |
