The application prospect of ultraviolet flame sensor will be broader
Human five sense organs are very complex and sensitive "sensors", but most people's five sense organs can only "qualitatively" perceive external information, not quantitative perceiving, and there are many physical quantities that human five senses cannot perceive. For example, they can perceive visible light for vision, but they cannot perceive the invisible spectrum with a wider frequency domain. These invisible lights can be sensed by infrared and ultraviolet flame sensors.
The five human tubes are very complex and sensitive"sensors",But most people’s facial features are only Can "qualitatively" perceive external information, but cannot perceive quantitatively,And there are many physical quantities that are human Not felt by the five senses. For example, they can perceive visible light for vision, but they cannot perceive the invisible spectrum with a wider frequency domain. These invisible lights can be sensed by infrared and ultraviolet flame sensors.
The ultraviolet flame sensor uses photoelectrons Emission effect photocell, span>It is characterized by responding only300,< /span>High sensitivity
UV tube is a cold cathode discharge diode, which utilizes the photoelectron emission effect of the cathode similar to a photocell. The special gas is sealed in the tube as the working medium of the discharge tube. A voltage is applied between the photocathode and the anode, which are only sensitive to ultraviolet light. The ultraviolet light passes through the glass cover and hits the cathode. Due to the action of the electric field, photoelectrons are attracted to the anode, but the output current is weak. If the applied voltage is increased, the electric field becomes stronger, and the photoelectrons are sufficiently accelerated to collide with the gas molecules in the tube to ionize the gas molecules. The electrons generated by gas ionization collide with gas molecules again, and finally cause a discharge phenomenon, thereby obtaining a large signal current. When working under DC voltage, if no special damping circuit is formed, the discharge will continue.
The UV tube is vacuum-sealed, and air pressure, temperature, humidity and other climatic factors have little effect on its use. When applied to 150 ~ 200C, the harmful substances on the glass bulb and lead of the tube will evaporate to the electrode due to thermal movement, and the spectral range will be expanded. However, the discharge purification electrode can still meet the requirements of fire monitoring, and the total life will be reduced. Strong vibration or shock will also affect the parameters of individual UV lamps. This is due to the harmful substances in the cathode returning to the cathode during the treatment process, resulting in the expansion of the spectral range. The processing requirements in the UV tube are very strict, and pollution should be minimized. The UV lamp can be stored for a long time, and the parameters of the lamp over the years will not change much.8 , Still does not affect the use. From the structural point of view, the parameters of the spherical cathode are easy to control because the discharge area is small and stable.
With the development of new mechatronics technology, the performance of the UV flame sensor will be further improved, its detection results will be more accurate, the detection distance will be longer, and dynamic detection Performance will be better,So the application prospect of ultraviolet flame sensor will be broader.