| 摘要 |
The thermal detection and visual alarm unit comprises a plurality of first expansion thermal detectors ( 17 ) with normally closed contacts that are connected in series with a first lamp ( 15 ) to form a first two-terminal circuit ( 21, 23 ), a plurality of second expansion thermal detectors ( 18 ) with normally open contacts connected in parallel, a second lamp ( 16 ) connected in series with the second thermal detectors to form a second two-terminal circuit ( 22, 24 ), the first and second thermal detectors forming a plurality of cells ( 19 ) each combining a first detector and a second detector having respective contact-opening or contact-closing temperatures that are substantially equal, each of said first and second two-terminal circuits being arranged for connection to the terminals of an electrical power supply ( 12 ).
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