SU553642A1 - Fire detector - Google Patents

Description

one

The invention relates to the field of automatic detection of fire by ultraviolet radiation of a flame and issuing a signal to fire extinguishing installations and may find application in the field of automatic control of the presence of a flame and control of the combustion of gas burners.

Known fire detector with a photon counter as a flame sensor 1, containing the synchronizer and the selection circuit, performed on the thyristor. The photon counter pulses are amplified and fed to the control electrode of the thyristor. When the pulses coincide with the half-wave supply voltage, the thyristor opens, and a capacitor is charged. When the thyristor is opened with pulses of large porosity, the capacitor has time to discharge, and the relay does not work. When irradiated, the photon counter produces pulses with a frequency of 50 Hz and more, the thyristor opens with each half-wave, the capacitor is charged, and the executive relay is activated.

The disadvantage of this detector is the false alarms when a photon series of background pulses of a series of background pulses are received in standby mode.

The closest technical solution to this invention is a fire detector comprising a sensor connected

with the key element connected to the power source 7 C-circuit, in parallel with the capacitor of which the key and threshold elements are connected, and the executive unit

2

The lack of accuracy of this detector is due to false positives.

The aim of the invention is to increase the reliability of the device weighing.

The goal is achieved by the fact that the proposed detector introduces an additional 7 C-circuit and an additional key element that is connected in parallel to the auxiliary / C-circuit capacitor and connected in series with the threshold element: the execution unit is connected in parallel to the auxiliary C-circuit capacitor that is connected to the power supply .

The drawing shows a schematic diagram of the device.

The device contains a sensor /, two Chain 2 and 3, two key elements 4 C 5, the threshold element 6 and the Executive unit 7.

The detector works as follows.

In standby mode, when the background pulses from the sensor / pass with a high porosity, the threshold element, with a frequency determined by integrating C-circuit 2, switches on key element 5 and discharges the integrating circuit capacitor 3. The charging time of the integrating circuit capacitor 2 to the threshold value is chosen so that the capacitor of the integrating circuit 5 does not have time to charge and issue a signal to the executive unit 7.

When the sensor I is irradiated, the time intervals between the pulses sharply decrease, the key element 4 activated by these pulses discharges the integrating circuit capacitor 2. The threshold element 6 does not send a control pulse to the key element 5, and it is closed. The capacitor of the integrating circuit 3 is charged to a value sufficient to trigger the execution unit 7, which generates a fire alarm. The use of the proposed detector in fire alarm installations increases the reliability of the fire notification, facilitates the work of the fire services, simplifies the fire alarm systems and allows the widespread use of automatic fire suppression installations.

Claims (2)

Invention Formula A fire detector containing a sensor connected to a key element connected to a C-circuit power source, parallel to the capacitor of which a key element and a threshold element are connected, the executive unit is also different in order to increase the reliability of the notice. a circuit and an additional key element that is connected in parallel to the capacitor by an additional C-circuit and in series) is connected to the threshold element; the executive unit is connected in parallel to the capacitor of the additional C-circuit, which is connected to the power SOURCE. Information sources taken into account during the examination: 1. Authorship of the USSR The USSR Law 358711, cl. G 08 B 17/12, dated 1965 2. Authorship certificate USSR L 225741, cl. G 08 At 29/00, dated July 10, 1967 (prototype).