A formaldehyde concentration detection device

Abstract

This utility model relates to the field of formaldehyde detection technology and discloses a formaldehyde concentration detection device, including a housing, a gas chamber and an infrared light emitter inside the housing. The gas chamber has a detection gas cavity, an inlet pipe and an outlet pipe, which are respectively connected to the two ends of the detection gas cavity. The gas chamber is made of transparent material. The infrared light emitter emits infrared light towards one side of the gas chamber, and a focusing element is arranged on the side of the infrared light emitter near the gas chamber. This utility model has a simple structure and low production cost. The focusing element collects the divergent light emitted by the light source and focuses it to the focal point, maximizing the light flux entering the detection gas cavity for detection, enhancing the signal strength, enabling the instrument to detect even the weakest concentration changes, and improving detection accuracy. The collimator shapes the divergent light into a parallel beam to accurately pass through the gas chamber and illuminate the infrared detector, ensuring accurate path and more stable and accurate detection.

Description

Technical Field

[0001] This utility model relates to the field of formaldehyde detection technology, and more specifically, to a formaldehyde concentration detection device. Background Technology

[0002] Formaldehyde is a colorless gas with a strong, pungent odor. It is gaseous at room temperature and has wide industrial applications, including in the plastics, synthetic fiber, leather, pharmaceutical, and dye industries. However, formaldehyde poses numerous health risks, including irritation, sensitization, and mutagenic effects, potentially causing respiratory and skin diseases, and even affecting reproductive health. Formaldehyde concentration testing in homes is a crucial measure to ensure the health and safety of residents. With advancements in technology and testing techniques, we can choose more accurate and convenient detection methods to monitor indoor formaldehyde concentrations. However, some existing formaldehyde detection devices are complex in structure, have low accuracy, and offer a poor user experience. Utility Model Content

[0003] To address at least one of the aforementioned problems, this utility model provides a formaldehyde concentration detection device, comprising a housing, within which a gas chamber and an infrared light emitter are disposed. The gas chamber includes a detection gas cavity, an inlet pipe, and an outlet pipe, respectively connected to both ends of the detection gas cavity. The gas chamber is made of a transparent material. The infrared light emitter emits infrared light toward one side of the gas chamber. A focusing element is disposed on the side of the infrared light emitter near the gas chamber, and a collimator is disposed between the focusing element and the gas chamber. An infrared light emitter is disposed on the side of the gas chamber away from the infrared light emitter. An external detector is included, with a filter positioned on the side of the infrared detector near the gas chamber. This filter transmits infrared light of the wavelength range that formaldehyde can absorb to the infrared detector. This formaldehyde concentration detection device has a simple structure and low production cost. It is equipped with a focusing element to collect the divergent light emitted by the light source and converge it to a focal point, maximizing the light flux entering the detection gas cavity for detection. This enhances the signal strength, enabling the instrument to detect even subtle concentration changes and improving detection accuracy. A collimator is also included to shape the divergent light into a parallel beam, ensuring accurate penetration through the gas chamber and onto the infrared detector. This accurate path results in more stable and accurate detection.

[0004] Optionally, a light-absorbing layer is provided on the outer side of the gas chamber along the circumferential direction. The light-absorbing layer has a light inlet hole and a light outlet hole, which are located on the path of the infrared light emitted by the infrared light emitter.

[0005] Optionally, the light-absorbing layer is a carbon black coating layer.

[0006] Optionally, the focusing element is a convex lens.

[0007] Optionally, a first filter cotton is connected between the air inlet pipe and the detection gas cavity, and a second filter cotton is connected between the air outlet pipe and the detection gas cavity.

[0008] Optionally, both the air inlet pipe and the air outlet pipe are made of Teflon.

[0009] Optionally, the infrared detector is a thermopile detector.

[0010] Optionally, a signal amplification circuit board electrically connected to the infrared detector is provided inside the housing.

[0011] Optionally, the housing includes a first housing and a second housing, the second housing being connected to the upper side of the first housing, the gas chamber cylinder, the infrared light emitter, the infrared detector, and the signal amplification circuit board being placed inside the first housing, and a display screen being provided on the second housing for displaying the formaldehyde concentration data detected in the detection gas chamber.

[0012] Compared with existing technologies, the formaldehyde concentration detection device of this utility model has a simple structure and low production cost; it is equipped with a focusing element to collect the divergent light emitted by the light source and converge it to the focal point, maximizing the light flux entering the detection gas cavity for detection, enhancing the signal strength, enabling the instrument to detect even the weakest concentration changes, and improving detection accuracy; it is equipped with a collimator to shape the divergent light into a parallel beam so that it accurately passes through the gas chamber and illuminates the infrared detector, ensuring accurate path and more stable and accurate detection. Attached Figure Description

[0013] Figure 1 This is a perspective view of the formaldehyde concentration detection device of this utility model;

[0014] Figure 2 This is a schematic diagram of the structure inside the first housing of the formaldehyde concentration detection device of this utility model;

[0015] Figure 3 A cross-section of the formaldehyde concentration detection device of this utility model. Figure 1 ;

[0016] Figure 4 for Figure 3 Enlarged view of section A in the middle;

[0017] Figure 5 A cross-section of the formaldehyde concentration detection device of this utility model. Figure 2 ;

[0018] The component names corresponding to the various labels in the figure are as follows: 1 is the housing, 11 is the first housing, 12 is the second housing, 13 is the display screen, 2 is the gas chamber, 201 is the first filter cotton, 202 is the second filter cotton, 21 is the detection gas cavity, 22 is the air inlet pipe, 23 is the air outlet pipe, 24 is the light-absorbing layer, 241 is the light inlet hole, 242 is the light outlet hole, 3 is the infrared light emitter, 4 is the focusing element, 5 is the collimator, 6 is the infrared detector, 61 is the filter, and 7 is the signal amplification circuit board. Detailed Implementation

[0019] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0020] In the description of this utility model, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship when the product is in normal use.

[0021] 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 at least one of that feature.

[0022] See Figures 1-5 This utility model provides a formaldehyde concentration detection device, including a housing 1. A gas chamber 2 and an infrared light emitter 3 are disposed within the housing 1. The gas chamber 2 has a detection gas cavity 21, an inlet pipe 22, and an outlet pipe 23. The inlet pipe 22 and the outlet pipe 23 are respectively connected to the two ends of the detection gas cavity 21. The gas chamber 2 is made of transparent material, specifically glass. The infrared light emitter 3 emits infrared light towards one side of the gas chamber 2. A focusing element 4 is disposed on the side of the infrared light emitter 3 near the gas chamber 2. A collimator 5 is disposed between the focusing element 4 and the gas chamber 2. A collimator 5 is disposed on the side of the gas chamber 2 away from the infrared light emitter 3. An external detector 6 and an infrared detector 6 are provided with a filter 61 on the side near the gas chamber 2. The filter 61 is used to transmit infrared light of the wavelength that formaldehyde can absorb to the infrared detector 6. The formaldehyde concentration detection device of this utility model has a simple structure and low production cost. It is equipped with a focusing element to collect the divergent light emitted by the light source and converge it to the focal point, maximizing the light flux entering the detection gas cavity for detection, enhancing the signal strength, enabling the instrument to detect weaker concentration changes, and improving detection accuracy. It is equipped with a collimator to shape the divergent light into a parallel beam so that it can accurately pass through the gas chamber and illuminate the infrared detector, ensuring accurate path and more stable and accurate detection.

[0023] Specifically, this formaldehyde concentration detection device operates based on the principle of non-dispersive infrared (NDIR) absorption spectroscopy. The detection process in this embodiment is as follows: 1. Emission and Preprocessing: The infrared emitter emits broadband infrared light, which is focused by a focusing element and then collimated into a parallel beam by a collimator, ensuring that the light passes perpendicularly and uniformly through the gas chamber. 2. Selective Absorption: The gas to be tested flows into the detection gas cavity from the inlet pipe. Formaldehyde molecules have characteristic absorption of infrared light of specific wavelengths; when parallel light passes through the gas, the intensity of this wavelength is reduced. 3. Detection and Recognition: When the transmitted light reaches the other side, the filter only allows light of the formaldehyde characteristic absorption band to pass through, eliminating other interfering wavelengths. The infrared detector accurately measures the degree of light intensity attenuation in this band. 4. Concentration Calculation: According to Beer-Lambert's law, light intensity attenuation is proportional to formaldehyde concentration; the detection value for no formaldehyde is a preset zero value, corresponding to a preset initial unattenuated light intensity value. The processor calculates the attenuation amount to determine a relatively accurate formaldehyde concentration in the gas. The collimator described above ensures accurate optical path and the filter ensures detection specificity, together achieving high-precision and interference-resistant quantitative detection. In this embodiment, the exhaust pipe can be connected to an air pump for air extraction, and the outside air is drawn into the detection gas chamber 21 through the intake pipe.

[0024] See Figures 2-4 A light-absorbing layer 24 is arranged circumferentially on the outer side of the gas chamber 2. The light-absorbing layer 24 has a light inlet 421 and a light outlet 422, which are positioned on the path of the infrared light emitted by the infrared light emitter 3. The light-absorbing layer can efficiently absorb scattered and reflected light that hits the outer wall of the gas chamber at various angles. If these stray lights do not reach the detector through absorption by the gas being measured, they will form stable background noise, severely interfering with the measurement of weak absorption signals. The light inlet and light outlet are precisely positioned on the direct path between the infrared light emitter and the infrared detector. They form a physical aperture, forcing only parallel light propagating along the designed optical axis (i.e., directly through the center of the gas chamber) to pass through the system. Any light deviating from this optical path will be absorbed by the light-absorbing layer. Through the above mechanism, only the effective measurement light signal can reach the detector. This greatly suppresses background noise, thereby significantly improving the signal-to-noise ratio of the system, enabling the instrument to detect the small light intensity changes caused by low concentrations of formaldehyde more sensitively and accurately.

[0025] See Figures 2-4The light-absorbing layer 24 is a carbon black coating layer. Carbon black is one of the blackest known substances and has a high light absorption rate. It can efficiently absorb non-ideal light (stray light) that hits the outer wall of the gas chamber at any angle (such as due to lens scattering or reflection from the inner wall of the gas chamber). Without this layer, this stray light would be reflected multiple times inside the gas chamber and eventually received by the detector, forming stable background noise that seriously interferes with the measurement signal. The carbon black layer ensures that only parallel light that is strictly along the optical axis and passes directly through the gas to be measured can reach the detector. This greatly suppresses background noise and allows the detector to respond only to the effective signal, thereby significantly improving the signal-to-noise ratio and measurement accuracy of the system. It is especially suitable for detecting weak signals of low-concentration formaldehyde.

[0026] See Figure 2 and Figure 3 The focusing element 4 is a convex lens, which has a simple structure and good focusing effect; it concentrates more light energy and passes it through the gas chamber, which means that the effective light flux passing through the formaldehyde gas being tested is greatly increased. The more photons absorbed by the formaldehyde molecules, the stronger the absorption signal generated; the convex lens focuses the light to the focal point, forming a bright and smallest light spot at that point, so that it can work with the collimator to emit bright and parallel light rays.

[0027] See Figure 2 and Figure 5 A first filter cotton 201 connects the inlet pipe 22 to the detection gas chamber 21, and a second filter cotton 202 connects the outlet pipe 23 to the detection gas chamber 21. This prevents contamination of the inner wall of the gas chamber: if dust, particulate matter, fibers, or other particles in the air directly enter the detection gas chamber 21, they will adhere to the transparent inner wall. This will significantly scatter and attenuate infrared light, leading to distorted measurement signals and severely inaccurate readings, thus ensuring the instrument's measurement accuracy remains stable.

[0028] See Figure 1 Both the intake pipe 22 and the exhaust pipe 23 are made of Teflon. Teflon has good inertness, its surface hardly adsorbs any gas molecules, and it releases almost no volatile substances, thus avoiding measurement errors introduced by it.

[0029] See Figure 2The infrared detector 6 is a thermopile detector that converts the infrared light intensity signal after passing through formaldehyde gas into a measurable electrical signal with high precision and stability. The thermopile is a thermal detector that can work stably at room temperature. The thermopile has a good response to a wide range of infrared light, which precisely covers the characteristic absorption band of formaldehyde. The housing 1 is equipped with a signal amplification circuit board 7 that is electrically connected to the infrared detector 6 so that the amplified signal can be transmitted to the control board for concentration calculation. The "clean" signal after amplification and filtering is transmitted to the microprocessor for algorithm calculation (such as applying Beer-Lambert's law), which can greatly reduce calculation errors and ensure the accuracy of the final concentration reading.

[0030] See Figure 1 and Figure 2 The housing 1 includes a first housing 11 and a second housing 12. The second housing 12 is connected to the upper side of the first housing 11. The gas chamber 2, infrared light emitter 3, infrared detector 6, and signal amplification circuit board 7 are all placed inside the first housing 11. A display screen 13 is installed on the second housing 12. The display screen 13 is used to display the formaldehyde concentration data detected in the gas detection chamber 21. The split design makes the product more modular, which is convenient for production and assembly. The optical module and the display module can be tested separately and then assembled, which improves production efficiency. If the display screen or the underlying optical sensor needs to be repaired, it can be operated independently without affecting each other, reducing maintenance costs. The infrared light emitter and signal processing circuit generate heat when working, and the display screen is also one of the heat sources. The split design can avoid heat concentration to a certain extent, which is conducive to heat dissipation and prevents high temperature from affecting the performance and service life of optical components.

[0031] The formaldehyde concentration detection device of this invention has a simple structure and low production cost. It is equipped with a focusing element to collect the divergent light emitted by the light source and converge it to the focal point, maximizing the light flux entering the detection gas cavity for detection, thereby enhancing the signal strength and enabling the instrument to detect even the weakest concentration changes, thus improving detection accuracy. It is also equipped with a collimator to shape the divergent light into a parallel beam, so that it can accurately pass through the gas chamber and illuminate the infrared detector, ensuring accurate path and more stable and accurate detection.

[0032] In the description of this disclosure, it should be understood that the terms "upper", "lower", "bottom", "inner", "outer", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to 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 disclosure.

[0033] Furthermore, the terms "first," "second," etc., 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 with "first," "second," etc., may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0034] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0035] In this disclosure, unless otherwise expressly specified and limited, the first feature "on" or "below" the second feature may be in direct contact with the first feature or in indirect contact with the first feature through an intermediate medium.

[0036] It should be noted that when a component is described as being "set on" another component, it can be directly on the other component or there may be an intervening component. When a component is described as "connected to another component," it can be directly connected to the other component or there may be an intervening component. Furthermore, when a component is described as being "fixedly connected" to another component, the connection can be detachable or non-detachable, such as through socketing, snap-fitting, integral molding, welding, etc., which are achievable in conventional technologies and will not be elaborated upon here.

[0037] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A formaldehyde concentration detection device, characterized in that, The device includes a housing (1), inside which is a gas chamber (2) and an infrared light emitter (3). The gas chamber (2) has a detection gas cavity (21), an inlet pipe (22), and an outlet pipe (23). The inlet pipe (22) and the outlet pipe (23) are respectively connected to the two ends of the detection gas cavity (21). The gas chamber (2) is made of transparent material. The infrared light emitter (3) is used to emit infrared light toward one side of the gas chamber (2). A focusing element (4) is provided on the side of the emitter (3) near the gas chamber (2), and a collimator (5) is provided between the focusing element (4) and the gas chamber (2). An infrared detector (6) is provided on the side of the gas chamber (2) away from the infrared emitter (3), and a filter (61) is provided on the side of the infrared detector (6) near the gas chamber (2). The filter (61) is used to transmit infrared light wavelengths that formaldehyde can absorb to the infrared detector (6).

2. The formaldehyde concentration detection device according to claim 1, characterized in that, A light-absorbing layer (24) is provided on the outer side of the gas chamber cylinder (2) along the circumferential direction. The light-absorbing layer (24) has a light inlet hole (421) and a light outlet hole (422). The light inlet hole (421) and the light outlet hole (422) are located on the path of the infrared light emitted by the infrared light emitter (3).

3. The formaldehyde concentration detection device according to claim 2, characterized in that, The light-absorbing layer (24) is a carbon black coating layer.

4. The formaldehyde concentration detection device according to claim 1, characterized in that, The focusing element (4) is a convex lens.

5. The formaldehyde concentration detection device according to claim 1, characterized in that, The inlet pipe (22) is connected to the detection gas chamber (21) by a first filter cotton (201), and the outlet pipe (23) is connected to the detection gas chamber (21) by a second filter cotton (202).

6. The formaldehyde concentration detection device according to claim 1, characterized in that, Both the air inlet pipe (22) and the air outlet pipe (23) are made of Teflon.

7. The formaldehyde concentration detection device according to claim 1, characterized in that, The infrared detector (6) is a thermopile detector.

8. The formaldehyde concentration detection device according to claim 1, characterized in that, The housing (1) contains a signal amplification circuit board (7) that is electrically connected to the infrared detector (6).

9. The formaldehyde concentration detection device according to claim 8, characterized in that, The housing (1) includes a first housing (11) and a second housing (12). The second housing (12) is connected to the upper side of the first housing (11). The gas chamber (2), the infrared light emitter (3), the infrared detector (6) and the signal amplification circuit board (7) are all placed inside the first housing (11). A display screen (13) is provided on the second housing (12). The display screen (13) is used to display the formaldehyde concentration data detected in the detection gas chamber (21).

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