Technical paper . A. ELEVATION OF TROUGH BARRIER WITH SIDE FRAME REMOVED, AND END S. LONGITUDINAL ELEVATION OF TROUGH BARRIER. ROCK-DUST BARRIERS. 41 the catch, by interposing a sheet of brass, will not exceed 15 pounds;aiid if 1 pound be allowed for the turning friction of the lever, theforce required to trip it is about 16 pounds. The tripping wires arcfastened to the tripping lever at points twice the distance from theaxis, 13, that the catches are, hence the pull required to trip tholever is about 8 pounds. For 6 levers the pull on one wire is about4S pounds, and for 12 levers, 6 on
Technical paper . A. ELEVATION OF TROUGH BARRIER WITH SIDE FRAME REMOVED, AND END S. LONGITUDINAL ELEVATION OF TROUGH BARRIER. ROCK-DUST BARRIERS. 41 the catch, by interposing a sheet of brass, will not exceed 15 pounds;aiid if 1 pound be allowed for the turning friction of the lever, theforce required to trip it is about 16 pounds. The tripping wires arcfastened to the tripping lever at points twice the distance from theaxis, 13, that the catches are, hence the pull required to trip tholever is about 8 pounds. For 6 levers the pull on one wire is about4S pounds, and for 12 levers, 6 on each wire, it is about 96 advance vane has about 8 square feet of exposed surface, and asone edge is hinged, the pressure required to operate the barrier isabout 24 pounds per square foot of vane surface. Such a pressurewould be given by an air current having a velocity of 70 miles perhour, or about 102 feet per second, as calculated from the Smeatonformula, P = V2, or if one uses the Martin formula, P = V2,by a current with a velocity of 113 feet per second. I
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectminesandmineralresou
