A photoionization sensor

Abstract

The utility model discloses a kind of photoionization sensors, comprising: lamp shell;Ultraviolet lamp is located at the side of lamp shell;Detector component is located above ultraviolet lamp, ionization cavity is equipped in detector component, and ultraviolet lamp is towards ionization cavity;Filtering component is located at the upper end inlet of detector component;Top cap is located on filtering component.The utility model can effectively remove large particle impurities, water vapor and small particulate matter in air by setting filter screen and filter membrane, ensure that the gas entering detector component is dry and clean.

Description

Technical Field

[0001] This utility model relates to the technical field of organic compound detection, and in particular to the technical field of a photoionization sensor. Background Technology

[0002] The rapid development of modern organic chemical and petroleum refining industries has brought humanity a wealth of new materials and products, greatly facilitating production and daily life. However, these industrial processes have also produced a series of toxic substances, such as carbon monoxide, hydrogen sulfide, nitrogen oxides, and formaldehyde, which seriously threaten human health.

[0003] In recent years, the number of indoor workers has increased dramatically. Indoor environments commonly suffer from poor air quality, inadequate ventilation, and high concentrations of volatile organic compounds (VOCs), which severely endanger people's physical and mental health. Building plastics such as engineered wood panels and foam insulation materials release large amounts of organic compounds; interior decoration materials like paints and coatings contain high concentrations of aldehydes, significantly increasing the risk of cancer; and office supplies such as detergents, inks, and typewriters also contain many harmful polymers. Even outdoor workers are not immune to vehicle exhaust and industrial fumes; oil and gas leaks, coking processes, and fugitive emissions also pose serious threats to health.

[0004] For the monitoring of organic compounds, there are many methods available on the market, which can be categorized according to their principles into semiconductor detection methods, catalytic combustion detection methods, electrochemical detection methods, flame ionization (FID) detection methods, and photoionization (PID) detection methods. Among these, photoionization (PID) detection methods are becoming increasingly widely used and possess relatively stable and mature technology, affecting most organic compounds. However, due to factors such as the manufacturing process of ultraviolet lamps, PID measurements are significantly affected by humidity, and the lifespan of the ultraviolet lamp is generally only 3 to 6 months, requiring periodic replacement. Utility Model Content

[0005] The technical problem to be solved by this application is the reduction in lifespan of ultraviolet lamps due to humidity in the prior art.

[0006] To address the aforementioned technical problems, this application provides a photoionization sensor, comprising:

[0007] Lamp housing;

[0008] An ultraviolet lamp, wherein the ultraviolet lamp is disposed on one side of the lamp housing;

[0009] A detector assembly is disposed above the ultraviolet lamp, and an ionization cavity is provided inside the detector assembly, with the ultraviolet lamp facing the ionization cavity;

[0010] A filter assembly is disposed at the upper inlet of the detector assembly;

[0011] A top cover is disposed on the filter assembly.

[0012] In the aforementioned photoionization sensor, the detector assembly includes, from top to bottom, a detector cover, a collecting electrode, a first interlayer, a grounding electrode, a second interlayer, a bias electrode, and a detector base plate.

[0013] In the aforementioned photoionization sensor, the detector assembly further includes a first metal plug and a second metal bolt; the input end of the first metal plug is connected to the collecting electrode, and the input end of the second metal plug is connected to the bias electrode; the output ends of both the first metal plug and the second metal plug are connected to the PCB board via pins.

[0014] In the aforementioned photoionization sensor, two clearance holes are respectively provided on both sides of the grounding electrode.

[0015] In the aforementioned photoionization sensor, the lamp housing is provided with an outer shell; a grounding electrode is connected to the outer shell, and the grounding electrode is connected to the ground.

[0016] In the aforementioned photoionization sensor, the detector is provided with a waterproof and breathable membrane on its exterior.

[0017] In the aforementioned photoionization sensor, one side of the lamp housing is provided with a housing for placing the ultraviolet lamp, one side of the housing is provided with a low-voltage electrode, and the other side of the housing is provided with a high-voltage electrode.

[0018] In the aforementioned photoionization sensor, a magnesium fluoride crystal is provided on the top of the ultraviolet lamp.

[0019] In the aforementioned photoionization sensor, the ultraviolet lamp contains a mixed gas consisting of krypton as the base gas and krypton 85 and argon.

[0020] In the aforementioned photoionization sensor, the ultraviolet lamp contains a nickel strip coated with a zirconium vanadium iron getter.

[0021] Compared with the prior art, the technical solution of this application has the following beneficial effects:

[0022] This invention, by incorporating a filter screen and a filter membrane, effectively removes large particulate impurities, water vapor, and fine particulate matter from the air, ensuring that the gas entering the detector assembly is dry and clean. This helps reduce the interference of impurities on the detection results, improving the sensor's detection accuracy and stability.

[0023] Furthermore, by placing the air inlet of the detector assembly at the top, this invention reduces the possibility of moisture entering the detector assembly. Simultaneously, by providing a waterproof and breathable membrane on the outside of the detector assembly, this invention effectively prevents moisture from the external environment from entering the interior of the detector assembly.

[0024] This invention utilizes a zirconium vanadium iron getter coated with nickel strips inside the ultraviolet lamp to adsorb residual gas molecules, thereby increasing the vacuum level inside the lamp tube and extending the lifespan of the ultraviolet lamp. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this application, and are not intended to limit this application.

[0026] Figure 1 This is an exploded view of a photoionization sensor according to the present invention.

[0027] Figure 2 This is an exploded view of the detector assembly of a photoionization sensor according to the present invention.

[0028] Figure 3 This is a cross-sectional view of the lamp housing and ultraviolet lamp of a photoionization sensor according to the present invention.

[0029] The annotations in the attached figures are explained as follows:

[0030] 1. Top cover; 21. Filter screen; 22. Filter membrane; 3. PCB board; 4. Detector assembly; 42. Air inlet; 421. First metal plug; 422. Second metal plug; 43. Detector top cover; 44. Collecting electrode; 451. First interlayer; 452. Second interlayer; 46. Grounding electrode; 461. Clearance hole; 47. Bias electrode; 48. Detector base plate; 49. Pin; 5. Ultraviolet lamp; 51. Housing; 6. Lamp housing; 601. Low-voltage electrode; 602. High-voltage electrode; 7. Outer shell; 8. Positioning pin. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the described embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this application pertains. The terms “first,” “second,” and similar terms used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a,” and similar terms, do not indicate a limitation of quantity, but rather indicate the presence of at least one.

[0033] like Figures 1 to 3 As shown, a photoionization sensor includes:

[0034] Lamp housing 6;

[0035] Ultraviolet lamp 5, the ultraviolet lamp 5 is located on one side of the lamp housing 6;

[0036] Detector assembly 4 is located above ultraviolet lamp 5. Detector assembly 4 has an ionization cavity 41 inside, and ultraviolet lamp 5 faces the ionization cavity 41.

[0037] A filter assembly is located at the air inlet 42 at the upper end of the detector assembly 4.

[0038] Top cover 1 is located on the filter assembly.

[0039] This invention provides installation space and protection for the ultraviolet lamp 5 through the lamp housing 6, ensuring the stable operation of the ultraviolet lamp 5. Furthermore, the ultraviolet lamp 5 of this invention faces the ionization cavity 41, effectively irradiating the ionization cavity with ultraviolet light, causing gas molecules to ionize. Moreover, because the air inlet 42 of the detector assembly 4 is located at its upper end, it is more difficult for moisture to enter the detector assembly 4.

[0040] In a preferred embodiment, the detector assembly 4 includes, from top to bottom, a detector cover 43, a collecting electrode 44, a first interlayer 451, a ground electrode 46, a second interlayer 452, a bias electrode 47, and a detector base plate 48. The detector cover 43 is located at the top of the detector assembly 4, protecting the internal structure and preventing external environmental influences such as dust and moisture. The collecting electrode 44 is located directly below the detector cover 43, and its main function is to collect electrons or ions generated by ionization. When gas molecules are ionized by ultraviolet light in the ionization chamber, the generated electrons or ions move towards the collecting electrode 44, thereby generating a current signal for subsequent signal processing and analysis. The first interlayer 451 is located between the collecting electrode 44 and the ground electrode 46, providing isolation and support. The first interlayer 451 is made of insulating material to ensure electrical insulation between the collecting electrode 44 and the ground electrode 46, preventing short circuits. The ground electrode 46 is located below the first interlayer 451, providing grounding and a stable potential reference for the detector assembly 4. The grounding electrode 46 helps eliminate electrostatic interference and improves the signal stability and accuracy of the detector assembly 4. The bias electrode 47, located below the second interlayer 452, primarily provides bias voltage or current to the detector assembly 4. The bias electrode 47 optimizes the detector's operating state, improving ionization efficiency and signal sensitivity. The detector base plate, located at the bottom of the entire detector assembly 4, supports and secures the entire assembly.

[0041] In a preferred embodiment, positioning holes 50 are provided on the front side of the detector cover 43, the collecting electrode 44, the first interlayer 451, the grounding electrode 46, the second interlayer 452, the bias electrode 47, and the detector base plate 48. By inserting the positioning pin 8 into the positioning hole 50, the precise positioning and fixing of each component can be achieved, ensuring the assembly accuracy and stability of the detector assembly 4.

[0042] In a preferred embodiment, such as Figure 2 As shown, the filter assembly includes a filter screen 21 and a filter membrane 22; the filter membrane 22 is disposed on the detector assembly 4, and the filter screen 21 is disposed on the filter membrane 22; the top cover 1 is disposed on the filter assembly.

[0043] The filter 21 effectively blocks large particulate impurities in the air, such as dust and fibers, preventing these impurities from entering the sensor and affecting its normal operation. Before the gas enters the filter membrane 22, the filter 21 performs preliminary filtration, reducing the burden on the filter membrane 22 and extending its service life. The filter membrane 22 further removes water vapor and fine particulate matter from the air, ensuring that the gas entering the detector assembly 4 is dry and clean. This is particularly important for photoionization sensors, as water vapor can affect the performance and ionization efficiency of the ultraviolet lamp 5.

[0044] In a preferred embodiment, such as Figure 2 As shown, the detector assembly 4 also includes a first metal plug 421 and a second metal bolt 422; the input terminal of the first metal plug 421 is connected to the collecting electrode 44, and the input terminal of the second metal plug 422 is connected to the bias electrode 47; the output terminals of both the first metal plug 421 and the second metal plug 422 are connected to the PCB board 3 via pins 49. Specifically, the input terminal of the first metal plug 421 is connected to the collecting electrode 44. The collecting electrode 44 generates a current signal during detection, and the function of the first metal plug 421 is to extract these signals from the collecting electrode 44. Similarly, the input terminal of the second metal plug 422 is connected to the bias electrode 47. The bias electrode 47 needs to provide a bias voltage or current to optimize the detector's operating state, and the function of the second metal plug 422 is to connect the bias electrode 47 to an external power supply or control circuit, thereby providing the required bias conditions.

[0045] Specifically, such as Figure 2 As shown, the output terminals of both the first metal plug 421 and the second metal plug 422 are connected to the PCB board 3 via pins 49. Pins 49 are a common connection method, enabling the transmission of the signal generated by the detector assembly 4 and the required bias voltage or current to the PCB board 3. The PCB board 3 integrates signal processing and control circuits, which amplify, filter, and perform analog-to-digital conversion on the signal generated by the detector assembly 4, and adjust the voltage or current of the bias electrode 47 as needed to achieve precise control of the detector and accurate signal measurement.

[0046] In a preferred embodiment, the collecting electrode 44, the grounding electrode 46, and the bias electrode 47 are all metal sheets. The first metal plug 421 on the left is connected to the irregular hole on the left side of the collecting electrode 44; the second metal plug 422 on the right is connected to the irregular hole on the right side of the bias electrode 47.

[0047] In a preferred embodiment, two clearance holes 461 are provided on both sides of the ground electrode 46. By providing clearance holes 461 on both sides of the ground electrode 46, electrical connection with either metal plug is avoided. This is because the main function of the ground electrode 46 is to provide a stable potential reference for the detector assembly 4 and to connect the housing of the detector assembly 4 to ground, thereby eliminating electrostatic interference and improving signal stability. The first metal plug 421 and the second metal plug 422 are respectively connected to the collecting electrode 44 and the bias electrode 47, and they have different potentials and functions in the circuit. If the ground electrode 46 comes into contact with either metal plug, it will cause an electrical short circuit or interference, affecting the normal operation of the detector assembly 4 and the accuracy of the signal.

[0048] In a preferred embodiment, the lamp housing 6 is provided with an outer casing 7; a grounding electrode 46 is connected to the outer casing 7 and is connected to the ground. By connecting the grounding electrode 46 to the ground, static electricity or leakage current on the equipment casing can be effectively conducted to the ground, preventing the equipment casing from becoming electrified, thereby avoiding electric shock accidents when users touch the equipment and improving equipment safety. At the same time, grounding can also protect the internal circuitry of the equipment from damage such as external electromagnetic interference and lightning strikes.

[0049] In a preferred embodiment, the detector assembly 4 is provided with a waterproof and breathable membrane on its exterior. This membrane effectively prevents moisture from the external environment (such as water droplets and water vapor) from entering the detector assembly 4. This is particularly important for photoionization sensors, as moisture can adversely affect critical components such as the ultraviolet lamp and ionization chamber, leading to decreased ultraviolet lamp performance and reduced ionization efficiency. By providing a waterproof and breathable membrane, the lifespan of the detector assembly 4 can be extended, and its reliability in humid environments can be improved.

[0050] In a preferred embodiment, a housing 51 for holding the ultraviolet lamp 5 is provided on one side of the lamp housing 6. A low-voltage electrode 601 is provided on one side of the housing 51, and a high-voltage electrode 602 is provided on the other side of the housing. By providing the low-voltage electrode 601 and the high-voltage electrode 602 on both sides of the housing 51, a stable electrode structure can be provided for the ultraviolet lamp 5. The low-voltage electrode 601 and the high-voltage electrode 602 are respectively connected to the two ends of the ultraviolet lamp, ensuring that the ultraviolet lamp can work normally and emit the required ultraviolet light. This electrode layout helps to maintain the stable discharge and light output of the ultraviolet lamp, improving the performance and reliability of the photoionization sensor.

[0051] In a preferred embodiment, the top of the ultraviolet lamp 5 is provided with a magnesium fluoride crystal. After the ultraviolet light emitted by the ultraviolet lamp 5 passes through the magnesium fluoride crystal, only ultraviolet light of a specific wavelength (10.6 eV) can be transmitted, while ultraviolet light of other wavelengths will be filtered out.

[0052] In a preferred embodiment, the ultraviolet lamp 5 contains a mixture of krypton as the base gas and krypton-85 and argon as dopants. Krypton, as the base gas, possesses high luminous efficiency and good spectral characteristics. During discharge, krypton generates strong ultraviolet light, which is crucial for photoionization sensors because the intensity of ultraviolet light directly affects the ionization efficiency of gas molecules and the sensor's detection sensitivity. By using krypton, the luminous efficiency of the ultraviolet lamp can be improved, thereby enhancing the sensor's performance. Krypton-85 is a radioactive isotope that releases high-energy electrons and gamma rays during its decay. These high-energy particles can further excite the krypton and argon, generating even more ultraviolet light. Argon is an inert gas, and its presence enhances the ionization capability within the ultraviolet lamp. During discharge, argon absorbs energy and ionizes, increasing the electron density within the ultraviolet lamp. Therefore, this mixture maintains a stable discharge state, is less susceptible to external environmental factors, and ensures stable operation of the ultraviolet lamp and reliable sensor performance.

[0053] In a preferred embodiment, the ultraviolet lamp 5 contains a nickel strip coated with a zirconium vanadium iron getter 51. The zirconium vanadium iron getter 51 is a non-evaporative adsorbent with selective gas extraction capabilities. Inside the ultraviolet lamp, the zirconium vanadium iron getter 51 can adsorb residual gas molecules, thereby increasing the vacuum level inside the lamp tube. Furthermore, the nickel layer acts as a catalyst and protector in the zirconium vanadium iron getter 51. Nickel catalyzes the decomposition and diffusion of hydrogen, promoting the adsorption of hydrogen by the zirconium vanadium iron getter 51, thus improving its getter performance. In addition, the nickel layer enhances the oxidation resistance of the zirconium vanadium iron in air, extending the getter's lifespan.

[0054] In addition to the above embodiments, this utility model also has the following working method:

[0055] The working principle is as follows:

[0056] There is a small positive voltage on the collecting electrode 44, and the entire bias electrode 47 is a -24V DC negative voltage (bias voltage). Therefore, there is an electric field between the two electrodes, with the field strength direction from the collecting electrode 44 to the bias electrode 47. At this time, the positive ions generated in the ionization region between the two electrodes flow to the bias electrode 47 under the action of the electric field, while the negative ions flow to the collecting electrode 44, thereby forming an induced current. This induced current is connected to the PCB through the first metal plug 421 connected to the irregular hole on the left side of the collecting electrode 44 for amplification.

[0057] The round holes on both sides of the detector cover 43 are for the first metal plug 421 or the second metal plug 422 and the connected pin 49 to pass through and screw together. The holes at the corresponding positions of the collecting electrode 44, the first interlayer 451, the grounding electrode 46, the second interlayer 452, the bias electrode 47 and the detector base plate 48 serve the same purpose as described above.

[0058] In addition, the central elliptical hole, i.e. the air inlet, of each of the above components is for the purpose of allowing gas to diffuse from the center into the ionization region, thereby generating an ion flow (i.e. facilitating gas diffusion); secondly, it facilitates ultraviolet light to irradiate the ionization region without being completely blocked.

[0059] The above are merely exemplary embodiments of this application and are not intended to limit the scope of protection of this application, which is determined by the appended claims.

Claims

1. A photoionization sensor, characterized in that, include: Lamp housing (6); Ultraviolet lamp (5), the ultraviolet lamp (5) is disposed on one side of the lamp housing (6); The detector assembly (4) is located above the ultraviolet lamp (5), and the detector assembly (4) has an ionization cavity (41) inside, with the ultraviolet lamp (5) facing the ionization cavity (41). A filter assembly is located at the upper inlet of the detector assembly (4); Top cover (1), the top cover (1) is disposed on the filter assembly.

2. The photoionization sensor according to claim 1, characterized in that, The detector assembly includes, from top to bottom, a detector cover (43), a collecting electrode (44), a first interlayer (451), a grounding electrode (46), a second interlayer (452), a bias electrode (47), and a detector base plate.

3. A photoionization sensor according to claim 2, characterized in that, The detector assembly further includes a first metal plug (421) and a second metal bolt (422); the input end of the first metal plug (421) is connected to the collecting electrode (44), and the input end of the second metal bolt (422) is connected to the bias electrode (47); the output ends of the first metal plug (421) and the second metal bolt (422) are both connected to the PCB board (3) via pins (49).

4. A photoionization sensor according to claim 2, characterized in that, Two clearance holes are provided on both sides of the grounding electrode (46).

5. A photoionization sensor according to claim 1, characterized in that, The lamp housing (6) is provided with an outer shell (7); a grounding electrode (46) is connected to the outer shell (7), and the grounding electrode (46) is connected to the ground.

6. A photoionization sensor according to claim 1, characterized in that, The detector assembly (4) is provided with a waterproof and breathable membrane on its exterior.

7. A photoionization sensor according to claim 1, characterized in that, The lamp housing (6) has a housing (51) on one side for placing the ultraviolet lamp (5), a low-voltage electrode (601) on one side of the housing (51), and a high-voltage electrode (602) on the other side of the housing.

8. A photoionization sensor according to claim 1, characterized in that, The top of the ultraviolet lamp (5) is provided with magnesium fluoride crystals.

9. A photoionization sensor according to claim 1, characterized in that, The ultraviolet lamp (5) contains a mixture of krypton gas as the base gas and krypton 85 and argon gas.

10. A photoionization sensor according to claim 1, characterized in that, The ultraviolet lamp (5) has a nickel strip inside, and the nickel strip is coated with zirconium vanadium iron getter.

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