Telegraph engineering : a manual for practicing telegraph engineers and engineering students (1922)
Hausmann, Erich, 1886- · New York : D. Van Nostrand Company · leaf 216
ter and a grounding switch. Fire-alarm boxes that are wound by the act of pullingthe starting lever, termed sector boxes, are also used, themechanisms being driven either by springs or weights. 3. Public Alarms. — In villages or towns having volun-teer fire brigades, the volunteers are called by… … Fig. 6. Fig. 7. 202 TELEGRAPH ENGINEERING blowing machine with a two-bell steam gong. This t5^eof public alarm gives satisfactory results where a steampressure of 80 pounds per square inch is maintained.The weight-driven mechanism opens the whistle valvesimultaneously with the circuit openings, and…
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