Facts and Fancy about Ventilation—II

Leonard Hill
1912 Scientific American  
Representative of Modern Mammoth Construction OUR frontispiece shows one 'of four large ' gate valves recently shipped by a well-known firm of Bridgeport, Connecticut, to a Canadian Colliery at Union Bay, B. C., to be used in connection with a hydro-electric plallt there. The valves consisted of two 72-inch and two 50inch standard iron body taper seat wedge gate valves with by-passes and spur gears. While such large valves are most commonly supplied for low-p,ressure work, the 72-inch on this
more » ... e 72-inch on this order will be used under a hydraulic working load of 125 pounds, and the 50-inch und�r a load of 165 pounds per square inch. They are massively constructed and have a large factor of safety, although built to retain as grace ful lines as possible in such large castings. The two mammoth 72-inch valves weigh 51,020 pounds and 49,080 pounds net each, respectively, averaging just about twenty-five rons apiece, this being about six tons heavier each than the low-pressure type. Of the two valves, the heavier, which was built to sustain a some what more severe strain than its companion, was tested to 240 pounds working pressure, and the other was tested to 175 pounds pressure by the customer?s in spectors. Both 50-inch valves, which weighed 20,010
doi:10.1038/scientificamerican12071912-367bsupp fatcat:vrjdyvp72zdbjfzignco6kehdm