Курсовая работа по модулю/дисциплине «Инжиниринг кип» на тему: «Fire and Gas Detection Philosophy»
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| Thermal sensors (Figure 1).
They work as a thermostat, that is, they measure and react to changes in temperature in the room. They can be installed anywhere in the house where the implementation of other detectors is not available. Thermal linear detectors are recommended for use in dusty, polluted, aggressive environments or at low temperatures. Since such detectors can be used in an aggressive environment, they have found popularity in industrial fire safety. Figure 1. Thermal sensors And standard thermal sensors are disposable and reusable. The first are allowed for use in small rooms. When triggered, the sensor sensor element exhausts its life and the detector must be replaced. Reusable, as the name implies, do not change after each operation. If we classify the heat detector by the type of reading parameter, then distinguish: Threshold; Differential; Combined. The first (threshold or maximum) is triggered when the permissible temperature level in the house is exceeded. According to this principle, the very first models of heat detectors were produced. They are not positioned as rapid response sensors, because the fire signal was given when the fire had already flared up enough and heat appeared. Differential analyzes the rate of temperature rise in the environment of its placement. If the heating of the medium deviates from the norm, the detector gives a signal about the beginning of a fire. Combined is a mixture of the first and second types. Taking the best qualities, it works if it notices too fast heating of the air and if the temperature has reached a threshold value. It is universal, more reliable and in demand in fire alarm systems. Thermal sensors have a special feature – there is no reaction to materials that do not emit heat. If you place such a detector on a high ceiling, because of the long distance, you can find out about the source of the fire much later or not at all. Smoke detectors (Figure 2) Figure 2. Smoke detectors Smoke detectors or smoke traps are more effective due to design features. They do not need to react to heat, measure it. The reaction to smoke can help prevent a fire even at the smoldering stage. There are differences in the operation of smoke traps, so they can be divided into two types according to their structure: Optical analyzers are common analyzers, the principle of operation of which is based on the operation of a light emitter together with a photodetector. Optical are divided into point and linear. Point smoke fire sensors send signals to the environment that dissipate if there is no smoke in the atmosphere. If the rays are reflected and hit the photodetector, then they are reflected from the smoke, and the alarm will turn on. Linear fire smoke detectors work as a receiver-transmitter. A beam of light is sent to the sensing element using an LED. If the goal is achieved, then the air is clean and there are no obstacles. If the light beam does not reach its target, the sensor gives an alarm signal. Ionization detectors are rare detectors whose principle of operation consists of constant monitoring of air through ventilation. A chamber containing oppositely charged particles is installed in the detector. With constant air intake, if smoke particles get inside, then electrons begin to react to them. The detector captures the reaction and sends an alarm signal. It is recommended to mount the smoke traps on the ceiling, closer to the hood, to ensure a quick effect and extinguish the incipient hearth before it develops into a real fire. Features of point sensors – they are not susceptible to black smoke. They require maintaining cleanliness to the room and regular cleaning. False positives can be triggered through steam and insects. Often, fire smoke detectors are used by electronics enthusiasts and are assembled on the basis of an Arduino controller. жүктеу/скачать 235,25 Kb. Достарыңызбен бөлісу:
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