AUTOMATIC FIRE ALARM.

Otago Witness, Issue 2915, 26 January 1910, Page 15

AUTOMATIC FIRE ALARM.

A number of persons connected with fire insurance companies, builders, electricians, and others gathered at 171 Princes street on Thursday afternoon to witness a demonstration of the Reichel automatic fire alarm. The inventor of the system is Mr L. T. Reichsl, late chief electrician. New Zealand Government Public Works Department, and it is claimed to be the most decided Advance in automatic fire alarms that has been made in recent times. It works on an entirely new and. novel principle, that of thermoelectricity, in which a current of electricity is generated by direct application of heat to certain metals. Simplicity, sensitiveness, and reliability .a.re its outstanding- features. The novelty erf the system commands attention. There m no expansion of metals or fluids, or fusing of wires, as in nearly every other electric system. _ No battery is required to operate the indicators. The hot air striking upon the thermopiles generates a current of electricity sufficiently strong to close a relay circuit which brings the alarm bells into action and calls no the brigade, with which, of course, the instillation is connected. The thermopiles themselves are about 4in in diameter, and consist of a number of thermo-couples of dissimilar metals mounted on a porcelain base. Part of. the metals is exposed, the rest being sunk in the base. An outbreak of fire causes a difference in temperature between the exposed and hidden metals, and this difference causes the current to flow. A slow rise of temperature such as occurs on a. hot day warms up the thermopiles evenly, and no current is generated. The system is thus immune against, false alarms. The thermopiles are fixed on the ceilings of the rooms to be protected, and are connected bv wires with the indicator board, which is mounted in the street window o>f the buildincr protected. There is one indicator for each floor, and means are provided for testing an entire installation in a few seconds. T he brigade is automatically disconnected while' the testing takes place. The system was given a five months' trial in the Government Buildings. Wdlin.aton. and Mr Holme* (the engincsr-in-chief) and Oaptain Hugo (inspector of fire _ brigades) expressed their approval of it in the Ktronn-est manner. Mr Rachel has but lately arrived from England and America.. where large companies made offers for the risrhts to Work the invention. Two large buildings in Wellington are already being equipped with the system, and the apparatus is now being- introduced into every citv in tha Dominion. The demonstration given on _ Thursday . afternoon wa-s of a most convincing nature, the whole and every part, being fhoroucrhly tested, auwarently to the entire satisfaction of those present.. A practical test showed that. a. sudden increase in the heat to the extent of mere.lv one degree caused the alarm to register in 10 seconds. while to illustrate that a slow rise in temperature does not aftect the alarm, there was an incubator on the premise* that had been warmed ur> slowly to 100 degrees of heat and which had no effect on the alarm. The sensitiveness of the thermoniiles mav be. trauged from the fact that bv mereilv breathing on them an alarm can be registered in three seconds, the warmth of the breath applied -to certain, mete Is contained in the thermopile creating the current of electricity.