GB190718949A - Improvements in or connected with Mercurial Thermostats or Temperature Alarms. - Google Patents

Abstract

18,949. Weguelin, W. H. Aug. 22. No Patent granted (Sealingfee not paid). Alarms, fire and temperature.-The mercury thermometers a used in firealarm systems are protected from accidental breakage and provided with means for detecting such breakage. The thermometers a are fixed in a shield c having a slot in one side and provided with a metal cover d with an opening in front and with extensions d<2> which protect the bulb while allowing free access of air. The connexions leading to the thermometer are fixed or cemented in the case in zigzag grooves h, and the device is screwed to a wall or ceiling block i. The thermometer is made with a vacuum above the mercury and has the usual wires e, f sealed in the glass, these wires being connected by the mercury when the temperature rises to a predetermined point. An additional wire g is sealed preferably at the top of the mercury in its lowest position, by means of which one of the circuits of the usual double-loop system is normally connected through the mercury in the thermometers. If one of the bulbs breaks, this circuit is broken, while all the remaining thermometers can still give the usual signal by reason of the double loop.