An ultraviolet sensor for monitoring the state of a boiler combustion flame

Abstract

The utility model discloses a kind of ultraviolet sensors for boiler combustion flame state monitoring, it is related to optical boiler combustion control sensing technical field, device includes metal shell, photoelectric conversion module, semiconductor ultraviolet detector and quartz optical fiber.Metal shell has inner cavity and pipe body passage;Photoelectric conversion module is fixed in inner cavity inside;Semiconductor ultraviolet detector is fixed in one end of pipe body passage close to inner cavity, its pin is connected with photoelectric conversion module;Quartz optical fiber one end is incident end, the other end is exit end, exit end is embedded in the other end of pipe body passage, and semiconductor ultraviolet detector is opposite and concentric shaft setting.This utility model passes through quartz optical fiber and conduction to sensor far from high temperature area with flame ultraviolet light signal, combine the heat isolation and electromagnetic shielding effect of metal shell, realize the high sensitivity, high stability detection of weak ultraviolet light signal, effectively avoid high temperature environment influence and external signal interference, improve the reliability and precision of boiler flame state monitoring.

Description

Technical Field

[0001] This utility model relates to the field of light boiler combustion control sensing technology, specifically an ultraviolet sensor for monitoring the state of boiler combustion flame. Background Technology

[0002] Boiler combustion is widely used in power generation, industrial heating, and other fields, and monitoring the combustion state of the flame is a crucial aspect of industrial boiler control. Currently, the market uses intensity detection of characteristic light emitted during flame combustion to determine the combustion state of the boiler flame. Optical sensors used for flame combustion state monitoring include infrared sensors, visible light sensors, and ultraviolet (UV) sensors. Among them, UV sensors monitor the ultraviolet light emitted during high-temperature combustion in flames (especially gaseous hydrocarbon fuels), offering advantages such as fast response speed and strong resistance to background infrared radiation.

[0003] Currently, most flame ultraviolet monitoring devices on the market are based on photocathode photomultiplier tubes. While these sensors offer high sensitivity, they generally suffer from drawbacks such as large size, the need for high-voltage operating conditions, and fragile, easily damaged structures. In contrast, ultraviolet detectors based on wide-bandgap semiconductor materials exhibit significant advantages in miniaturization.

[0004] However, when applied to boiler flame monitoring, the ultraviolet signal of the flame is relatively weak and attenuates significantly during transmission in the air. The detector must be placed close to the high-temperature flame, which can easily exceed the operating temperature limit of conventional electronic components (usually below 100°C), causing the photoelectric conversion circuit to fail. Moreover, these detectors are also sensitive to non-flame ultraviolet sources in the environment, such as electric arcs and sunlight, which poses a high risk of false alarms. Utility Model Content

[0005] The purpose of this invention is to provide an ultraviolet sensor for monitoring the combustion flame status of boilers, in order to solve the above-mentioned problems.

[0006] The technical solution of this utility model is: An ultraviolet sensor for monitoring the state of boiler combustion flame includes: a metal housing with an inner cavity and a tube channel connecting the inner cavity; a photoelectric conversion module fixed inside the inner cavity of the metal housing; the photoelectric conversion module converts the current signal generated by the semiconductor ultraviolet detector into a measurable voltage or current signal or a digital signal; the gain of the photoelectric conversion module is greater than 1 GΩ. The photoelectric conversion module is equipped with a metal shield to effectively shield the coupling of weak external signals caused by the high gain, avoiding any impact on the signal stability of the photoelectric conversion module. The semiconductor ultraviolet detector is fixed inside the tube channel of the metal housing near one end of the inner cavity, and the pins of the semiconductor ultraviolet detector are connected to the photoelectric conversion module; the semiconductor ultraviolet detector converts the ultraviolet light in the received light signal into a current signal; a quartz optical fiber, one end of which is the flame light incident end and the other end of which is the flame light emitting end, is used to guide the radiation fiber in the flame to the wide bandgap semiconductor ultraviolet detector, and the emitting end is embedded in the other end of the tube channel of the metal housing, opposite to the semiconductor ultraviolet detector, and the quartz optical fiber and the semiconductor ultraviolet detector are arranged concentrically. To improve the measurement accuracy of ultraviolet light from boiler combustion flames and reduce optical loss, the quartz optical fiber is metal-armored.

[0007] In use, the incident end of the quartz optical fiber is fixed at the boiler flame monitoring window to monitor the boiler combustion flame. The ultraviolet light of the flame passes through the quartz optical fiber and is transmitted through the emitting end of the quartz optical fiber to the semiconductor ultraviolet detector located inside the metal casing. The metal casing is far away from the combustion flame so that its internal operating temperature can be kept below 85°C. The semiconductor ultraviolet detector converts the light signal into a current signal. The photoelectric conversion module converts the current signal generated by the semiconductor ultraviolet detector into a measurable voltage / current / digital signal. The voltage / current / digital signal is then transmitted to the boiler combustion control system through wires.

[0008] Furthermore, in order to improve the transmission efficiency of ultraviolet light from the boiler combustion flame, the emitting end of the quartz optical fiber is a lens structure; the diameter of the quartz optical fiber is between 200 micrometers and 300 micrometers, and the quartz optical fiber is a bundled fiber with 20 to 50 fiber cores.

[0009] Furthermore, the optical window of the semiconductor ultraviolet detector is equipped with a quartz lens to improve the light collection efficiency of the semiconductor ultraviolet detector.

[0010] Furthermore, the response band of the semiconductor ultraviolet detector is 180nm~400nm. This response band can accurately cover the characteristic ultraviolet spectrum generated when gaseous hydrocarbons burn in boiler flames, effectively improving the accuracy of flame identification and the ability to resist background interference.

[0011] Furthermore, the output signal of the photoelectric conversion module is either an analog signal or a digital signal, wherein the analog signal is either a voltage signal or a 4mA~20mA current signal. By using multiple signal output formats, the device can flexibly adapt to different industrial control system interfaces, thereby improving the device's compatibility.

[0012] Furthermore, the incident end of the quartz optical fiber has a temperature resistance greater than 300°C; the light guiding efficiency of the quartz optical fiber at wavelengths of 200nm to 400nm is higher than 70%. The high temperature resistance and high light guiding efficiency ensure that the ultraviolet light signal can still be stably and efficiently transmitted to the semiconductor ultraviolet detector in a high-temperature environment, thereby improving the signal transmission quality.

[0013] Furthermore, the distance between the emitting end of the quartz optical fiber and the semiconductor ultraviolet detector is 0cm to 3cm. By controlling the short distance or close connection between the emitting end and the semiconductor ultraviolet detector, the diffusion and attenuation of the light signal in the air are minimized, thereby further improving the detection sensitivity and response speed.

[0014] Compared with the prior art, the beneficial effects of this utility model are: This invention utilizes quartz optical fiber to guide the ultraviolet light signal of the boiler flame over a long distance to a semiconductor ultraviolet detector far from the high-temperature area. Combined with a metal casing for thermal isolation and electromagnetic shielding of the photoelectric conversion module, it achieves high sensitivity and high stability detection of weak ultraviolet light signals under harsh environments with strong interference and high temperature. This effectively solves the problems of traditional ultraviolet sensors being prone to overheating failure of electronic components due to proximity to high-temperature flames and being susceptible to external electromagnetic interference, significantly improving the reliability and accuracy of boiler combustion flame status monitoring. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the internal structure of this utility model.

[0016] Figure 2 This is a schematic diagram showing the change of the output voltage signal of this utility model over time.

[0017] Figure 3 This is a schematic diagram of the response speed of this utility model.

[0018] Among them, 101 is the incident end, 102 is the quartz optical fiber, 103 is the output end, 104 is the semiconductor ultraviolet detector, 105 is the photoelectric conversion module, and 106 is the metal casing. Detailed Implementation

[0019] The following is combined Figures 1 to 3The specific embodiments of this utility model will be described in detail below. In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0020] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0021] It should be noted that the circuit connections involved in this utility model all adopt conventional circuit connection methods and do not involve any innovation.

[0022] Example like Figure 1As shown, an ultraviolet sensor for monitoring the combustion flame status of a boiler includes: a metal housing 106, a photoelectric conversion module 105, a semiconductor ultraviolet detector 104, and a quartz optical fiber 102. The metal housing 106 has an inner cavity and a tube channel connecting the inner cavity. The photoelectric conversion module 105 is fixed inside the inner cavity of the metal housing 106. The photoelectric conversion module 105 converts the current signal generated by the semiconductor ultraviolet detector 104 into either an analog signal or a digital signal. The analog signal is either a voltage signal or a 4mA~20mA signal. Multiple signal output formats allow the device to flexibly adapt to different industrial control system interfaces, improving the device's compatibility. The photoelectric conversion module 105 has a gain greater than 1 GΩ. The photoelectric conversion module 105 is equipped with a metal shielding cover to effectively shield the coupling of weak external signals caused by the high gain, avoiding any impact on the signal stability of the photoelectric conversion module 105. A semiconductor ultraviolet detector 104 is fixed within the pipe channel of a metal casing 106, near one end of the inner cavity. The pins of the semiconductor ultraviolet detector 104 are connected to a photoelectric conversion module 105. The semiconductor ultraviolet detector 104 converts the ultraviolet light in the received optical signal into a current signal. A quartz optical fiber 102 has one end as the flame light incident end 101 and the other end as the flame light emitting end 103. The incident end 101 is close to the flame, and the emitting end 103 is embedded in the other end of the pipe channel of the metal casing 106. The quartz optical fiber 102 guides the radiation from the flame to the wide-bandgap semiconductor ultraviolet detector 104. The emitting end 103 and the semiconductor ultraviolet detector 104 are positioned opposite each other, and the quartz optical fiber 102 and the semiconductor ultraviolet detector 104 are concentrically aligned. This improves the measurement accuracy of ultraviolet light from boiler combustion flames and reduces light loss. The quartz optical fiber 102 is metal-clad.

[0023] In use, the incident end 101 of the quartz optical fiber 102 is fixed at the boiler flame monitoring window to monitor the boiler combustion flame. The ultraviolet light of the flame passes through the quartz optical fiber 102 and is transmitted through the emitting end 103 of the quartz optical fiber 102 to the semiconductor ultraviolet detector 104 located inside the metal casing 106. The metal casing 106 is far away from the combustion flame so that its internal operating temperature can be lower than 85°C. The semiconductor ultraviolet detector 104 converts the light signal into a current signal. The photoelectric conversion module 105 converts the current signal generated by the semiconductor ultraviolet detector 104 into a measurable voltage / current signal / digital signal. The voltage / current signal / digital signal is transmitted to the boiler combustion control system through a wire.

[0024] To improve the transmission efficiency of ultraviolet light from boiler combustion flames, the output end 103 of the quartz optical fiber 102 is a lens structure; the diameter of the quartz optical fiber 102 is between 200 micrometers and 300 micrometers, and the quartz optical fiber 102 is a bundled fiber with 20 to 50 fiber cores.

[0025] The optical window of the semiconductor ultraviolet detector 104 is equipped with a quartz lens to improve the light collection efficiency of the semiconductor ultraviolet detector 104.

[0026] The semiconductor ultraviolet detector 104 has a response band range of 180nm~400nm. This response band can accurately cover the characteristic ultraviolet spectrum generated by the combustion of gaseous hydrocarbons in boiler flames, effectively improving the accuracy of flame identification and the ability to resist background interference.

[0027] The incident end 101 of the quartz optical fiber 102 has a temperature resistance greater than 300℃; the light guiding efficiency of the quartz optical fiber 102 at wavelengths of 200nm~400nm is higher than 70%. The high temperature resistance and high light guiding efficiency ensure that the ultraviolet light signal can still be stably and efficiently transmitted to the semiconductor ultraviolet detector 104 in a high-temperature environment, thus improving the signal transmission quality.

[0028] The distance between the emitting end 103 of the quartz optical fiber 102 and the semiconductor ultraviolet detector 104 is 0cm to 3cm. By controlling the short distance or close connection between the emitting end 103 and the semiconductor ultraviolet detector 104, the diffusion and attenuation of the light signal in the air are minimized, thereby further improving the detection sensitivity and response speed.

[0029] like Figure 2 As shown, the peak-to-peak fluctuation of the output voltage signal of the photoelectric conversion module 105 under ultraviolet light irradiation is less than 20mV, and the signal fluctuation is <1.5%, indicating that the photoelectric conversion module 105 has strong anti-interference ability and excellent output signal stability; Figure 3 As shown, the photoelectric conversion module 105 has a light response speed of <30ms, which can meet the monitoring requirements of boiler flame combustion status.

[0030] The above-disclosed embodiments are merely preferred embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. An ultraviolet sensor for monitoring the combustion flame status of a boiler, characterized in that, include: The metal outer shell (106) has an inner cavity and a tube channel connecting the inner cavity; The photoelectric conversion module (105) is fixed inside the cavity of the metal shell (106); A semiconductor ultraviolet detector (104) is fixed in the pipe channel of the metal shell (106) at one end near the inner cavity, and the pins of the semiconductor ultraviolet detector (104) are connected to the photoelectric conversion module (105). The quartz optical fiber (102) has a flame light incident end (101) at one end and a flame light emitting end (103) at the other end. The emitting end (103) is embedded in the other end of the pipe channel of the metal shell (106) and is arranged opposite to the semiconductor ultraviolet detector (104). The quartz optical fiber (102) and the semiconductor ultraviolet detector (104) are arranged concentrically.

2. The ultraviolet sensor for monitoring the combustion flame state of a boiler according to claim 1, characterized in that, The output end (103) of the quartz optical fiber (102) is a lens structure; the diameter of the quartz optical fiber (102) is between 200 micrometers and 300 micrometers, and the quartz optical fiber (102) is a bundled optical fiber with a fiber core count of 20 to 50 cores.

3. The ultraviolet sensor for monitoring the combustion flame state of a boiler according to claim 1, characterized in that, The optical window of the semiconductor ultraviolet detector (104) is equipped with a quartz lens.

4. The ultraviolet sensor for monitoring the combustion flame state of a boiler according to claim 1, characterized in that, The response wavelength range of the semiconductor ultraviolet detector (104) is 180nm~400nm.

5. The ultraviolet sensor for monitoring the combustion flame state of a boiler according to claim 1, characterized in that, The output signal of the photoelectric conversion module (105) is either an analog signal or a digital signal, wherein the analog signal is either a voltage signal or a 4mA~20mA current signal.

6. The ultraviolet sensor for monitoring the combustion flame state of a boiler according to claim 1, characterized in that, The incident end (101) of the quartz optical fiber (102) has a temperature resistance greater than 300℃.

7. The ultraviolet sensor for monitoring the combustion flame state of a boiler according to claim 1, characterized in that, The distance between the output end (103) of the quartz optical fiber (102) and the semiconductor ultraviolet detector (104) is 0cm to 3cm.

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