FIRE SIGNALUnfortunately, not all premises are equipped with fire detectors. Especially dangerous in this respect, workshops and warehouses, areas with hay or fuel and lubricants. Offer the design of fire alarm is simple device that does not require for the manufacture of scarce materials.

The sensor in it is in plastic tape or nylon fishing line. She stretched under the ceiling of the room; its ends held in a horizontal position two signal flag. In the event of hearth deck, tape or fishing line melts, freeing the signal flags, which, under the action of the counterweights be in a vertical position, and thus the arisen danger. Parallel to the visual alarms it is possible to arrange also the alarm system via the normal elektrosvarka or siren including contacts can be closed by turning the axis of the box is melted or breakage of the tape.
Fig. 1. Mechanical diagram of fire alarm of nylon fishing line.
Fig. 1. Mechanical diagram of fire alarm of nylon fishing line.
Fig. 2. Diagram of a differential sensor responsive to the rate of increase in temperature
Fig. 2. Diagram of a differential sensor responsive to the speed of increasing temperature:
And with a slow increase of temperature, both threads are changing the same; — with a sharp increase in temperature primarily extends unsecured thread.
A variant of this alarm is a differential sensor: it responds not to absolute temperature, and the speed of its growth. The base fixture — two nylon fishing line. One is placed in a screen having thermal inertia, and other such screen does not. If the speed of ascending temperature is low — for example, when the increase in temperature from night to day (difference of about 20°) — both filaments are heated almost identically, and angular displacements of the rocker arm, which is attached to both of the line, is not observed. With sharp increase of temperature (when the fire) warm up the filaments without heat shield ahead of the heating filament with shield: this causes a rotation of the rocker arm and circuit contacts fire detector.
N. BEZBORODOV, Dolgoprudny, Moscow oblast

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