RU58760U1 - SMOKE FIRE DETECTOR - Google Patents

Abstract

The inventive utility model relates to the field of fire alarm, namely, devices for detecting fire, accompanied by the appearance of smoke in enclosed spaces of various buildings and structures, by registering optical radiation reflected from smoke particles and sending a “Fire” notice to the control panel via a loop fire alarm systems, as well as fire alarms with light indicators. The inventive utility model solves the technical problem of increasing the reliability of the detector. This goal is achieved in that in a smoke detector containing a light indicator, terminals for connecting to a fire alarm loop, one-way conduction element, current limiting element, storage capacitor, first current switch, pulse generator, amplifier, comparison circuit, counter, second current switch , a photodiode emitting an infrared diode, a second current-limiting element, an inverter, according to the claimed utility model, an additional contact and a loop voltage control circuit are introduced, with holding an input resistive divider, a comparator, an AND-NOT logic element, a generator. The proposed technical solution improves the reliability of the smoke detector by introducing an additional contact and loop voltage control circuit. An additional contact connected to the positive loop wire provides duplicate detector contact. If one of the contacts malfunctions, the loop voltage control circuit generates a warning signal about the detector malfunction. The detector continues to function normally. This allows maintenance personnel to detect the detector with a faulty contact, eliminate the contact fault and ensure the smooth functioning of the fire alarm system. The industrial model is developed, mastered and manufactured industrially by the ITC Limited Liability Company, St. Petersburg, Russia.

Description

The inventive utility model relates to the field of fire alarm, namely, devices for detecting fires, accompanied by the appearance of smoke in enclosed spaces of various buildings and structures, by registering optical radiation reflected from smoke particles and sending a “Fire” notification to the control panel via a loop fire alarm systems, as well as fire alarms with light indicators.

Known smoke fire detector (Optical smoke electronic smoke detector IP 212-44 "DIP-44" IVS-SIGNAL SPETSAVTOMATIKA, CATALOG of products for fire automation systems manufactured by enterprises of Obninsk, Obninsk, 2002), containing terminals for connecting to the cable fire alarm, LED indicator, current switch, one-way conduction element, current limiting element, storage capacitor, pulse generator, emitting infrared diode, photodiode, amplifier, comparison circuit and counter. In standby mode, the LED indicator is turned off by the current switch, so it is not possible to separate the standby mode from the inoperative state of the detector.

As a prototype of the selected smoke detector described in the patent of the Russian Federation 2250505, 7 G 08 B 17/107, G 08 B 17/12, publ. 04/20/2005, containing a light indicator, terminals for connecting to a fire alarm loop, one-way conduction element, current limiting element, storage capacitor, first current switch, pulse generator, amplifier, comparison circuit, counter, second current switch, infrared photo diode diode, second current limiting element, inverter. This detector is connected to a two-wire fire alarm loop in a three-pin circuit. With this scheme, two contacts are used to connect the detector to the negative cable of the loop into the gap, which allows the control panel to control the presence of the detector in the loop. The third contact is used to connect to the positive loop wire. The LED indicator generates short light pulses with long intervals between these flashes. By this optical signal, it is possible to judge the operability of a smoke detector.

The disadvantage of the prototype is that during the long-term operation of the fire alarm system, the detector’s contact, connected to the positive loop cable and switching consumption current of an insignificant value, may lose its working capacity due to various environmental factors and design reasons, that is, it ceases to conduct current. The control panel does not control the operability of this contact, therefore it is possible to detect such a contact failure in which the detector ceases to perform its function of detecting fire only visually, by the light indicator when checking the operation of the detectors by maintenance personnel. In this case, before the detection of a faulty detector, the integrity of the loop will be violated, and the reception of a fire signal from other detectors of this loop will become impossible. The average expected residence time of a room without protection due to a detector failure can be several days (I. Maslov. Self-diagnosis of detectors. “BDI”, No. 4, 2004).

The inventive utility model solves the technical problem of increasing the reliability of the detector by duplicating the contact and controlling the loop voltage.

This goal is achieved in that in a smoke detector containing a light indicator, terminals for connecting to a fire alarm loop, one-way conduction element, current limiting element, storage capacitor, first current switch, pulse generator, amplifier, comparison circuit, counter, second current switch , a photodiode emitting an infrared diode, a second current-limiting element, an inverter, according to the claimed utility model, an additional contact and a loop voltage control circuit are introduced, with holding an input resistive divider, a comparator, an AND-NOT logic element, a generator.

The technical solution proposed in the utility model increases the reliability of the detector. An additional contact connected to the positive loop wire provides duplication of the detector contact; if one contact fails, the other will work, and the detector will perform its function of detecting fire. In the standby mode of operation, when both detector contacts are in good condition, the voltage of the same magnitude is supplied to the two inputs of the loop voltage control circuit. If one of the contacts fails, the signal at one of the inputs of the loop voltage control circuit disappears, a warning signal about the detector malfunction is formed, which is expressed in the blinking of the indicator light with a higher frequency. The detector continues to function normally. This allows maintenance personnel to detect the detector with a faulty contact, eliminate the contact fault and ensure the smooth functioning of the fire alarm system.

Figure 1 presents the structural diagram of the inventive smoke detector, figure 2 an example of the circuit voltage control loop.

Here

1 - indicator light,

2, 3, 4, 5 - terminals,

6 - storage capacitor,

7 - the first current switch,

8 - pulse generator,

9 - amplifier

10 is a comparison diagram,

11 is a counter

12 - the second current switch,

13 - photodiode,

14 - emitting infrared diode,

15 - current limiting element,

16 - inverter,

17, 18 - element of one-sided conductivity,

19 is a current limiting element,

20 is a loop voltage control circuit,

21 - input resistive divider,

22-25 - current limiting elements,

26 is a comparator,

27 - logical element AND NOT,

28 - generator.

The inventive smoke detector works as follows. When a supply voltage is supplied to the input terminals 2, 5 and 3 through the unilateral conduction elements 17, 18 and the current-limiting element 19, the storage capacitor 6 is charged. The unilateral conduction elements 17, 18 protect other elements of the smoke detector when the polarity of the supply voltage is incorrectly connected. While the voltage at the terminals of the storage capacitor 6 is not enough for the normal operation of the smoke

fire detector, at the output of the comparison circuit 10, a high potential level is formed, which is fed to the reset input of the counter 11 and by which a low logic level is established at its output. The second current switch 12 will be closed and LED 1 will be turned off. At the same time, the low potential level that comes from the output of the counter 11 to the input of the pulse generator 8 allows the operation of this generator 8. At the output of the pulse generator 8, short pulses with a duration of several tens of microseconds are generated with a repetition period of about one second. These pulses are fed to the comparison circuit 10 and through the inverter 16 to the input of the first current switch 7. The first current switch 7 provides discharge of the storage capacitor 6 to the emitting infrared diode 14 and to the LED indicator 1. The pulse of the emitting infrared diode 14 is received by the photodiode 13, fed amplifier 9. The amplified pulse from amplifier 9 is fed to the input of the comparison circuit 10. If the pulses arriving at the comparison circuit 10 are below the set level, then there will be no pulses at the output of the comparison circuit 10 which go to the input of the counter 11, and on the output of the comparison circuit 10, on the contrary, there will be reset pulses of the counter 11. After reaching the specified voltage drop across the storage capacitor 6, a potential is established at the output of the current-limiting element 15, which ensures the normal operation of other detector elements. The value by which the storage capacitor 6 will be discharged will depend on the duration and period of the pulses that appear at the output of the pulse generator 8, as well as the ratio of the charge current of the storage capacitor 6 through the current-limiting element 19 to the discharge current of this capacitor 6 through the first current switch 7 and radiating infrared diode 14. The discharge of the storage capacitor 6 through the output of the first current switch 7 to the LED indicator 1 is much lower current than through the radiating infrared first diode 14. In the standby mode, the LED 1 generates short light pulses with long intervals between the flashes. By this optical signal, it is possible to judge the operability of a smoke detector. In this operating mode, when the detector contacts 2, 5 are in good condition, the voltage of the same magnitude is supplied to the two analog inputs of the comparator 26 of the loop voltage control circuit 20 through the input resistive divider 21. If there are two identical voltages at the input of the comparator, the I-NOT 27 logic element blocks the generator 28. If one of the contacts 2 or 5 fails, the signal at one of the inputs of the comparator 26 disappears, the I-NOT 27 logic element starts the generator 28, which generates a warning signal about malfunction of the detector contact, expressed in the flashing of indicator light 1 with a higher frequency. At the same time, the detector continues to function normally, since the loop voltage is supplied through a working contact 2 or 5.

In standby mode, while the optical density of air is lower than the set level, for each pulse at the output of the pulse generator 8, the counter 11 is reset. When the smoke level reaches the set level, that is, with an increase in the optical density of air, the scattered radiation intensity increases. In this case, for each pulse at the output of the pulse generator 8, the state of the counter 11 will increase by one until the senior discharge of the counter 11 is switched over, according to which the further pulse counting by the counter 11 is prohibited. If there is a high potential level at the high level of the counter 11, the second current key 12, this signal prohibits the operation of the pulse generator 8. In this case, the detector circuit detects the “Fire” state, which is registered by the fire alarm system and is indicated by a constant Eternal LED 1. Display the smoke detector out of this state is only possible to disconnect the supply voltage

time sufficient to discharge the storage capacitor 6 to a value at which a high potential level is established at the output of the comparison circuit 10.

The proposed technical solution improves the reliability of the smoke detector by introducing an additional contact and loop voltage control circuit. An additional contact connected to the positive loop wire provides duplicate detector contact. If one of the contacts malfunctions, the loop voltage control circuit generates a warning signal about the detector malfunction. The detector continues to function normally. This allows maintenance personnel to detect the detector with a faulty contact, timely eliminate the contact fault and ensure the smooth functioning of the fire alarm system.

The industrial model was developed, mastered and manufactured industrially by the ITC Limited Liability Company, St. Petersburg, Russia.

Claims (1)

A smoke detector containing an LED indicator and terminals for connecting to a fire alarm loop, the first of which is connected to the input of a one-way conduction element, the output of which is connected to the input of the first current-limiting element, the output of which is connected to the first output of the storage capacitor and the first output of the first current key, the second terminal of the storage capacitor is connected to the second terminal and the first terminals of the power supply of the pulse generator, amplifier, comparison circuit and counter, output connected to the inputs of the second current switch and the pulse generator, the output of which is connected to the first input of the comparison circuit, the second input of which is connected to the output of the amplifier, and the first output of the comparison circuit is connected to the counter input of the counter, the reset input of which is connected to the second output of the comparison circuit, the second the power output of which is connected to the second power outputs of the counter, pulse generator and amplifier, the inputs of which are connected to the terminals of the photodiode optically connected to the emitting infrared diode, and the first output of the current switch is connected to the output of the one-way conduction element, the first and second terminals of the inverter power are connected respectively to the first and second terminals of the pulse generator power supply, the output of which is connected to the inverter input, and the inverter output is connected to the input of the first current switch, the input of the second current-limiting element is connected to the output of the first current-limiting element, and the output to the second output of the counter power, the anode of the emitting infrared diode is connected to the second output of the first current switch, and the cathode is with a second terminal and a cathode of the LED indicator, the anode of which is connected to the second output of the second current switch and the third output of the first current switch, characterized in that the detector additionally has a terminal connected to the input of the second one-sided conductivity element, the output of which is connected to the input of the first current-limiting element, and the loop voltage control circuit, the second input of which is connected to the first terminal, containing the input resistive divider, the outputs of which are connected to the comparator, the output omparatora through a logical AND-NO element is connected to the generator and output circuit is connected to the anode of the LED.