What are the classification of the flame detector?
Flame detector is a new word for you, for a long time, for our understanding of the fire is not to grasp, along with the development of science, people gradually know the flame, also invented the understanding of the flame of tools -
Flame detector, which is mainly composed of probe and signal processor two parts.
The classification of the flame detector: 1, ultraviolet flame detector ultraviolet flame detector using ultraviolet light tube as sensing element, the spectral range in O.
Ultraviolet light tube is a kind of solid state pulse device, the signal of pulse frequency is itself and ultraviolet radiation frequency proportional random pulse.
Ultraviolet light tube has two electrodes, usually with ac high voltage.
When the radiation of ultraviolet light on the electrode is strong enough, has a 'avalanche' impulse current between the electrode and its frequency is related to the intensity of the ultraviolet light, up to a few thousand Hertz.
When the fire, no pulse.
2, visible flame detector visible flame detector using photoelectric diode as sensing element, the spectral response range from 0.
33 ~ 0.
Visible flame detector by the probe, chassis parts and cooling equipment, etc.
Furnace flame in the visible light through the probe, the end of the lens through the optical fiber to probe the little room, according to the photodiode.
The photodiode will be visible light signal is converted into a current signal, through the logarithmic amplifier is converted into a voltage signal.
Logarithmic amplifier output voltage signal is converted to current signal through the transmission amplifier.
Then, through the shielding cable transmission to chassis.
In the case, the current signal is converted to voltage signal.
On behalf of the flame of voltage signal was sent to a frequency detection circuit, intensity detecting circuit and fault detection circuit.
Strength detection circuit is equipped with two different threshold, the upper limit and lower limit value.
When the flame intensity than upper limit, the light intensity, said fire;
When strength is lower than the lower limit value, the intensity of lights, said the fire fighting.
Frequency detection circuit used to detect flicker frequency furnace flame, it according to the flame flicker frequency is above or below a set frequency, can correctly judge has no flame furnace.
Fault detection circuit has two limit, in normal circumstances, the value between the upper and lower limit.
Once the chassis signal input circuit malfunction, such as cable bolt of photocell to case, the voltage signal is immediately deviation from the normal range, and a fault alarm signals.
3, infrared flame detector infrared flame detector is the use of lead sulfide or cadmium sulfide photosensitive resistance as a sensing element, the spectral response range from 0.
Infrared flame detector is composed of probe, chassis and cooling equipment.
Burner flame of a burning area of the infrared radiation, through the optical fiber to probe, through the probe of photosensitive resistance is converted into electrical signals, then amplified by the amplifier.
The flame signal by the shielded cable to the chassis, through frequency response after switch and an amplifier, again the same reference voltage (