. Engineering and Contracting . ng Distance Water Stage Recorder. Current is supplied to these circuits from a 110-volt D. line at the Weather Bureau office. A phosphor bronze tape attached to a 21-in. diameter floatand counterweight passes over the sprocket wheel of thesender to which are geared two bent metal contact tubescontaining mercury. Each tube is divided longitudinally byan insulated partition having openings near the bent side of the tube connects with a ground wire, the (145) 648 Engineering and Contractiiu/ for June 9, 1920. other to a line wire. One tube operates
. Engineering and Contracting . ng Distance Water Stage Recorder. Current is supplied to these circuits from a 110-volt D. line at the Weather Bureau office. A phosphor bronze tape attached to a 21-in. diameter floatand counterweight passes over the sprocket wheel of thesender to which are geared two bent metal contact tubescontaining mercury. Each tube is divided longitudinally byan insulated partition having openings near the bent side of the tube connects with a ground wire, the (145) 648 Engineering and Contractiiu/ for June 9, 1920. other to a line wire. One tube operates on rising stage, theother on falling stage. As the float fluctuates up and downin the stilling well with the changing river stage, these con-tact tubes swing through small arcs and make electric con-tacts whenever the stage rises or falls one-twentieth of afoot. At that instant, a steel pawl releases its control overthe movement of the unbalanced contact tube, which swingsquickly back to normal position. This causes the mercury. U. S. Geological Survey Stream Flow Measuring Station on KansasRiver at Topeka, Kan. The Sending Instrument of the LongDistance Water Stage Recorder Is Located in the Re-inforced Concrete Weil and Shelter. to rush to the bent end, where a mercury-on-mercury surfacecontact is made. These tubes have been severely testedwith heavy loads of 120 volts without any failure or sign ofdeterioration, and insure positive, sparkless contacts. Thesealed tubes insure at all times clean mercury sprocket wheel of the sender also forms part of an operated by two pairs of magnets, one for rising, the otherfor falling stage. The operating arms, which are attachedto the magnet armatures, turn the ratchet wheel one notch,each time either magnet is energized, corresponding to achange of stage of one-twentieth of a foot at the arms also are provided with interlocking stops thatprevent the wheel from turning more than one notch, untilthe magnet is
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