All Fish Are Not in the Sea

Issue 17 and Volume 81.

All Fish Are Not in the Sea Firemen who work around pumpers know that it is possible for fish to find their way into city water mains and to later clog the strainers used as a safeguard on pumper intakes. While making fire flow tests in Chicago, engineers of the Factory Mutual discovered some interesting facts. A 1,500gallon and a 1,000-gallon centrifugal pump at the buildings of the Central Manufacturing District take suction from the city mains. Running at full speed, the larger pump delivered only 996 gallons a minute at a pressure of forty-two pounds instead of 1,500-gallons or better at one hundred pounds pressure. The suction line, normally under 24-pound pressure, showed an 18-inch vacuum. The results suggested some obstruction either in the meter or the fish trap on the pipe leading front the street main. When the cover was removed from the fish trap, the screen was…

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