An ultraviolet flame detector for monitoring flame combustion conditions in an aeroengine
By employing a double-lens design and nano-aerogel thermal insulation material in the ultraviolet flame detector for aero-engines, combined with convex lens focusing and phototube structure optimization, the problems of reduced sensitivity and optical lens contamination at high temperatures were solved, achieving stable detection in high-temperature environments.
Patent Information
- Application Number
- CN202611315746.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-27
- Publication Date
- 2026-11-03
AI Technical Summary
Existing ultraviolet flame detectors for aero-engines suffer from reduced sensitivity in high-temperature environments, their optical lenses are easily contaminated, affecting detection accuracy, and their phototubes lack sufficient sensitivity, making them prone to missed detections.
By employing a double-lens design and nano-aerogel insulation material, combined with convex lens focusing and optimized internal structure of the phototube, the high temperature resistance and anti-pollution performance are improved.
Maintaining the sensitivity and reliability of the detector in high-temperature environments, reducing the impact of optical lens contamination on detection, and improving the sensitivity and anti-interference capability of the phototube.
Smart Images
Figure CN123028696A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of flame detectors, specifically relating to an ultraviolet flame detector for monitoring the combustion of flames in aircraft engines. Background Technology
[0002] Aircraft engine flame detectors are essential components of aircraft engine systems. Ultraviolet flame detectors monitor the flame intensity in the engine's afterburner and determine the combustion status based on the flame intensity, thus identifying whether the engine has stalled during afterburning.
[0003] Existing engine ultraviolet flame detectors suffer from several drawbacks: short-term high temperatures of 245°C (not exceeding 10 minutes per flight hour) reduce the sensitivity of the ultraviolet phototube and shorten the lifespan of the PCB board and photosensitive light; optical lenses are easily contaminated, affecting detection accuracy; and the phototube's sensitivity is insufficient, leading to missed detections. Therefore, developing a high-temperature resistant and contamination-resistant ultraviolet flame detector for aero-engines is essential. Summary of the Invention
[0004] The purpose of this invention is to provide an ultraviolet flame detector for monitoring the combustion of flames in aircraft engines, thereby addressing the aforementioned problems.
[0005] This invention is mainly achieved through the following technical solutions: An ultraviolet flame detector for monitoring the combustion of flames in an aero-engine includes a housing, a convex lens, a plane mirror, and a phototube. The housing has a window on one side and a detachable rear cover assembly on the other side. From the outside to the inside, the convex lens and the plane mirror are arranged sequentially at the window. The phototube is positioned on the side of the rear cover assembly closest to the plane mirror, and a PCB board is placed between the phototube and the rear cover assembly. A nano-aerogel layer is deposited on the inner surface of the housing, and nano-aerogel is filled between the PCB board and the rear cover assembly.
[0006] To better realize the present invention, a limiting installation end is further provided on the inner periphery of the window, and a lens pressure ring is detachably provided on the inner side. A convex lens is provided between the lens pressure ring and the limiting installation end, and a plane mirror is installed in the middle of the lens pressure ring.
[0007] To better realize the present invention, one end of the lens retaining ring is further connected to the window opening thread.
[0008] To better realize the present invention, the inner thread of the window is further provided with a connecting ring, and a convex lens is provided between the connecting ring and the limiting mounting end, and one end of the lens pressure ring is connected to the internal thread of the connecting ring.
[0009] To better realize the present invention, both the convex lens and the plane mirror are made of high-temperature resistant, high-purity quartz glass JGS1 material, and the convex lens and the plane mirror form a double-layer lens cavity to achieve a heat insulation effect.
[0010] To better realize the present invention, the focusing distance of the convex lens is 15mm and the diameter is 40mm.
[0011] To better realize the present invention, the thickness of the nano-aerogel layer is further 3~6mm.
[0012] To better realize the present invention, the phototube 4 is further welded and fixed on the PCB board 7, and a connector is installed on the top of the housing. The ultraviolet phototube is used to generate current and discharge under ultraviolet light irradiation. The PCB board is used to obtain a voltage signal related to the received radiation energy after being conditioned by a signal conditioning circuit, and output through the connector 9.
[0013] To better realize the present invention, the wavelength of the ultraviolet light is further defined as 185~260nm.
[0014] In aero-engines, flame detectors are frequently exposed to high-temperature combustion environments; therefore, they require high-temperature resistance and contamination resistance. To improve the detector's high-temperature resistance, this invention employs a double-lens design and nano-aerogel insulation material filling technology. By placing two lenses at the detector's optical window, heat energy is reduced from entering the flame detector through the observation window, thus protecting the internal photosensitive elements. Simultaneously, filling the detector with high-temperature insulation material can reduce internal temperature changes in a short time, effectively improving the detector's high-temperature resistance.
[0015] This invention utilizes an ultraviolet (UV) phototube as the sensing element. It is a sealed glass tube that transmits UV light and contains an anode and cathode, along with a special gas. The cathode is made of a metallic material sensitive only to UV light. Applying a voltage across the UV phototube establishes an electric field between the electrodes. When UV light irradiates the tube, a photoelectric effect occurs, emitting photoelectrons from the photocathode surface. Under the influence of the electric field, these photoelectrons collide at extremely high speeds with surrounding gas molecules, ionizing them into positive ions and electrons. These ions then travel to the anode, rapidly generating a large current and discharging. A subsequent signal conditioning circuit then conditions this current to obtain a voltage signal related to the received radiation energy.
[0016] To improve the detector's resistance to contamination, this invention employs convex lens focusing and optimized internal phototube structure techniques. By using convex lens focusing technology, the refractive index, transmittance, and Poisson's ratio parameters of the lens are determined based on the positions of the anode and cathode of the phototube, improving the lens's ability to collect ultraviolet radiation and thus enhancing sensitivity. This allows light to be more concentrated into the phototube, thereby improving its sensitivity and anti-interference performance. Simultaneously, by optimizing the internal structure of the phototube, the gap between the anode and cathode is shortened, and the structural strength of the anode and cathode metal materials is increased to prevent accidental contact due to vibration. The shortened distance between the anode and cathode allows for conduction even with less ultraviolet light energy due to lens contamination, improving contamination resistance and sensitivity. This, in turn, maintains the detector's sensitivity and reliability.
[0017] The beneficial effects of this invention are as follows: This invention employs ultraviolet light detection technology to monitor the combustion of flames in aero-engines. It utilizes a double-lens system consisting of a convex lens and a plane mirror, and fills the inner surface of the detector housing with nano-aerogel insulation material to synergistically improve high-temperature resistance. Furthermore, this invention employs a convex lens for focusing and optimizes the internal structure of the phototube to achieve an anti-contamination design. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the structure of the ultraviolet flame detector for an aero-engine of the present invention; Among them: 1-convex lens, 2-plane mirror, 3-lens retaining ring, 4-phototube, 5-housing, 6-nano aerogel, 7-PCB board, 8-back cover assembly, 9-connector. Detailed Implementation
[0019] Example 1: An ultraviolet flame detector for monitoring the combustion of flames in aircraft engines, such as Figure 1 As shown, inside the housing 5, a convex lens 1 and a plane mirror 2 are fixed at the opening of the housing 5 using a lens retainer ring 3. Nano-aerogel 6 is filled between the inner surface of the housing 5 and the PCB board 7 and the rear cover assembly 8. The phototube 4 is soldered and fixed to the PCB board 7 and then assembled inside the housing 5. The structure is simple, reliable, and easy to assemble. When a certain voltage is applied across the ultraviolet phototube 4, and ultraviolet light with a wavelength of 185~260nm irradiates it, a large current is rapidly generated and discharged from the anode and cathode of the ultraviolet phototube 4. After being conditioned by the signal conditioning circuit on the PCB board 7, a voltage signal related to the received radiation energy is obtained and output through connector 9.
[0020] High-Temperature Resistant Design: To ensure the detector operates normally in high-temperature environments, this embodiment employs a double-lens design and fills the inner surface of the detector housing 5 with nano-aerogel 6 thermal insulation material. Preferably, the external convex lens 1 and the plane mirror 2 are both made of high-temperature resistant, high-purity quartz glass JGS1 material, forming a double-lens cavity to achieve thermal insulation. A 3-6mm layer of nano-aerogel 6 thermal insulation material is fixed to the inner surface of the detector. These two measures effectively reduce the internal temperature of the detector under short-term high temperatures of 245℃ (not exceeding 10 minutes / flight hour).
[0021] Anti-contamination design: The phototube 4 should be highly sensitive to ultraviolet light and possess high stability and reliability. In this embodiment, the gap between the anode and cathode of the phototube 4 is shortened, while the structural strength of the metal materials of the anode and cathode is increased to prevent accidental contact between the anode and cathode due to vibration. To ensure the detector's sensitivity to flames, the convex lens 1 needs to be designed with high focusing efficiency. Preferably, in this embodiment, a convex lens 1 with a focusing distance of 15mm and a diameter of 40mm is used, taking into account the installation position of the ultraviolet phototube 4.
[0022] The PCB conversion circuit is a crucial component that amplifies and converts the signal detected by phototube 4. In this embodiment, temperature compensation is also implemented to address the decrease in sensitivity of phototube 4 due to excessively high temperatures, ensuring the detector's ability to detect flames. Furthermore, to ensure the detector's anti-interference capability, a filter circuit is added to the PCB circuit board to filter out other interference signals.
[0023] The entire detector was tested under high-temperature conditions and with varying degrees of contamination on the convex lens 1. The accuracy and stability of the detector were then assessed using testing instruments. The results show that the detector in this example exhibits a higher voltage signal output value than existing detectors under high-temperature conditions and with varying degrees of contamination on the convex lens 1.
[0024] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.
Claims
1. An ultraviolet flame detector for monitoring the combustion of flames in aircraft engines, characterized in that, The device includes a housing (5), a convex lens (1), a plane mirror (2), and a phototube (4). The housing (5) has a window on one side and a rear cover assembly (8) that can be detachably installed on the other side. The convex lens (1) and the plane mirror (2) are arranged sequentially from the outside to the inside at the window. The phototube (4) is arranged on the side of the rear cover assembly (8) near the plane mirror (2), and a PCB board (7) is arranged between the phototube (4) and the rear cover assembly (8). A nano-aerogel layer is provided on the inner surface of the housing (5), and nano-aerogel (6) is filled between the PCB board (7) and the rear cover assembly (8).
2. The ultraviolet flame detector for monitoring the combustion of flames in an aero-engine according to claim 1, characterized in that, The inner periphery of the window is provided with a limiting installation end, and a lens pressure ring (3) is detachably provided on the inner side. A convex lens (1) is provided between the lens pressure ring (3) and the limiting installation end, and a plane mirror (2) is installed in the middle of the lens pressure ring (3).
3. The ultraviolet flame detector for monitoring the combustion of an aero-engine flame according to claim 2, characterized in that, One end of the lens retaining ring (3) is threadedly connected to the window opening.
4. An ultraviolet flame detector for monitoring the combustion of flames in an aircraft engine according to claim 2 or 3, characterized in that, The inner thread of the window is provided with a connecting ring, and a convex lens (1) is provided between the connecting ring and the limiting installation end. One end of the lens pressure ring (3) is connected to the internal thread of the connecting ring.
5. The ultraviolet flame detector for monitoring the combustion of flames in an aircraft engine according to claim 1, characterized in that, Both the convex lens (1) and the plane mirror (2) are made of high-temperature resistant, high-purity quartz glass JGS1 material, and the convex lens (1) and the plane mirror (2) form a double-layer lens cavity to achieve heat insulation effect.
6. An ultraviolet flame detector for monitoring the combustion of flames in an aircraft engine according to claim 1 or 5, characterized in that, The focusing distance of the convex lens (1) is 15mm and the diameter is 40mm.
7. An ultraviolet flame detector for monitoring the combustion of an aircraft engine flame according to claim 1 or 5, characterized in that, The thickness of the nano-aerogel layer is 3~6mm.
8. The ultraviolet flame detector for monitoring the combustion of flames in an aircraft engine according to claim 1, characterized in that, The phototube (4) is welded and fixed on the PCB board (7), and a connector (9) is installed on the top of the housing (5). The ultraviolet phototube (4) is used to generate current and discharge under ultraviolet light irradiation. The PCB board (7) is used to obtain a voltage signal related to the received radiation energy after being conditioned by the signal conditioning circuit, and output through the connector (9) 9.
9. An ultraviolet flame detector for monitoring the combustion of flames in an aircraft engine according to claim 8, characterized in that, The wavelength of the ultraviolet light is 185~260nm.