A modular optoacoustic cell with tunable resonator parameters

Abstract

The utility model provides a kind of resonant cavity parameter tunable's modularization photoacoustic cell, it include: two buffer chambers, two connecting devices and a resonant cavity, one of two buffer chambers is provided with air inlet, one is provided with air outlet;Wherein, the resonant cavity two ends each connection one end of connecting device, the other end of connecting device each connection one buffer chamber, the mode that connecting device connects the resonant cavity with buffer chamber is all detachable connection mode.The utility model can be according to the light beam size of different laser, divergence angle and other parameters and the detection demand of different resonant frequency, flexible replacement matching resonant cavity, solve the problem that traditional photoacoustic cell structure is fixed, cannot be matched with different laser beam characteristics;Solve the problem that different resonant frequency of photoacoustic cell is needed in different application scenarios and solve the problem that maintenance cost of traditional photoacoustic cell is high, compatibility is low.

Description

Technical Field

[0001] This utility model belongs to the field of gas detection technology, specifically relating to a modular photoacoustic cell with tunable resonant cavity parameters. Background Technology

[0002] Photoacoustic spectroscopy, as a highly sensitive gas detection method, is widely used in environmental monitoring, industrial process control, and other fields. In photoacoustic detection systems, the photoacoustic cell, as the core component for generating and amplifying photoacoustic signals, has a decisive impact on the overall system performance due to its structural design. Traditional photoacoustic cells mainly consist of a buffer cavity and a resonant cavity. The buffer cavity primarily mitigates disturbances caused by incoming and outgoing gases. When gas enters the photoacoustic cell from the inlet pipe, it introduces turbulence or pressure fluctuations. If the gas directly enters the resonant cavity, it will severely interfere with the sound field. The buffer cavity acts as an acoustic buffer, absorbing most of the non-periodic disturbances. The resonant cavity is the most critical structure in the photoacoustic cell, mainly used for amplifying the photoacoustic signal. The length, radius, and shape of the resonant cavity affect the resonant frequency of the photoacoustic cell and the amplification factor of the photoacoustic signal. Currently, most photoacoustic cells use resonant cavities of fixed dimensions and structures, with their length and inner diameter being preset and non-replaceable, combined with a gas buffer cavity to form an integrated device. Although this type of resonant cavity is generally a standard cylindrical shape, it is used as a fixed structure for gas detection after manufacturing. However, in specific applications, there are requirements for the resonant frequency of the photoacoustic cell in different scenarios, and there are differences in parameters such as beam diameter and divergence angle of different lasers. The resonant cavity with a fixed structure cannot be effectively matched with it, resulting in the disadvantages of low photoacoustic signal and high noise, which limits the flexibility and scalability of the system.

[0003] Currently, most mainstream photoacoustic cell structures are integrated designs, mainly consisting of a fixed resonant cavity and a buffer cavity. However, the existing technology CN221945848U discloses a split-type fiber optic sensing photoacoustic cell that allows the resonant cavity and buffer cavity to be separated through a specific structure. After a certain period of online use, it can be disassembled and cleaned, enabling the photoacoustic cell to be reused repeatedly, thus reducing costs compared to integrated photoacoustic cells. However, this patent's design focuses on structural separability and reusability, and does not address the issue of structural matching for different beam parameters and resonant frequency requirements. Utility Model Content

[0004] To address the aforementioned problems in the existing technology, this invention provides a modular photoacoustic cell with tunable resonant cavity parameters. The technical problem to be solved by this invention is achieved through the following technical solution: A modular photoacoustic cell with tunable resonant cavity parameters includes: two buffer cavities, two connecting devices, and one resonant cavity. One of the two buffer cavities is provided with an air inlet, and the other is provided with an air outlet. The resonant cavity is connected to one end of a connecting device at each end, and the other end of the connecting device is connected to a buffer cavity. The connecting devices connect the resonant cavity and the buffer cavity in a detachable manner.

[0005] Optionally, both connecting devices include a resonant cavity connecting end and a buffer cavity connecting end; the resonant cavity connecting end is connected to one end of the corresponding resonant cavity, and the buffer cavity connecting end is connected to the corresponding buffer cavity.

[0006] Optionally, the two connecting devices further include O-rings, with one O-ring provided at the bottom end of each of the resonant cavity connecting end and the buffer cavity connecting end.

[0007] Optionally, the two connecting devices are screws, the resonant cavity connecting end is a first external thread, the buffer cavity connecting end is a second external thread, the resonant cavity is provided with first threaded holes at both ends, the buffer cavity is provided with a second threaded hole at the end facing the resonant cavity, the first threaded hole on the resonant cavity is connected to the first external thread, and the second threaded hole on the buffer cavity is connected to the second external thread.

[0008] Optionally, the outer diameters of the first external thread and the second external thread are different.

[0009] Optionally, the inner diameter of the first threaded hole is in the range of 4mm-10mm, and the outer diameter of the first external thread corresponds to the inner diameter of the first threaded hole.

[0010] Optionally, the length of the resonant cavity ranges from 40mm to 90mm.

[0011] Beneficial effects: 1. This utility model can quickly replace the resonant cavity with matching structural parameters according to the requirements of different laser light source spot size, divergence angle and other parameters, as well as different resonant frequencies, effectively improving the maximum response of photoacoustic signals.

[0012] 2. This utility model can flexibly cope with different detection scenarios by replacing the resonant cavity with a different structure, without having to replace the entire photoacoustic cell system, thus improving the versatility and expandability of the equipment.

[0013] 3. The resonant cavity of this invention can be independently disassembled, replaced, and cleaned, reducing system maintenance costs and downtime.

[0014] 4. This utility model, through its modular design, facilitates users to switch between cavities with different modal characteristics, making it suitable for scientific research and development as well as product iteration, and possessing significant research and engineering value.

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a modular photoacoustic cell with tunable resonant cavity parameters provided by this utility model; Figure 2 This is a schematic diagram of the connecting device provided by this utility model. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0018] This invention provides a modular photoacoustic cell with tunable resonant cavity parameters. The matching resonant cavity module can be flexibly replaced according to the beam size, divergence angle and other parameters of different lasers and the detection requirements of different resonant frequencies. This solves the problem that the traditional photoacoustic cell has a fixed structure and cannot be matched with the beam characteristics of different lasers; it solves the problem that the photoacoustic cell cannot be used in different application scenarios with different resonant frequencies; and it solves the problems of high maintenance cost and low compatibility of traditional photoacoustic cells.

[0019] like Figure 1 As shown, this utility model provides a modular photoacoustic cell with tunable resonant cavity parameters, including: two buffer cavities 2, two connecting devices 3, and one resonant cavity 4. One of the two buffer cavities 2 is provided with an air inlet, and the other is provided with an air outlet; both the air inlet and the air outlet are located in... Figure 1 The standard is 1. The resonant cavity 4 is connected to one end of a connecting device 3 at each end, and the other end of the connecting device 3 is connected to a buffer cavity 2. The connecting device 3 connects the resonant cavity 4 and the buffer cavity 2 in a detachable manner.

[0020] refer to Figure 2 As shown, both connecting devices of this utility model include a resonant cavity connecting end 5 and a buffer cavity connecting end 7; the resonant cavity connecting end 5 is connected to one end of the corresponding resonant cavity 4, and the buffer cavity connecting end 7 is connected to the corresponding buffer cavity 2. The two connecting devices also include an O-ring seal 6, with an O-ring seal 6 provided at the bottom end of both the resonant cavity connecting end 5 and the buffer cavity connecting end 7.

[0021] Combination Figure 1 and Figure 2 The two connecting devices are screws, the resonant cavity connecting end is a first external thread, the buffer cavity connecting end is a second external thread, the resonant cavity is provided with a first threaded hole at both ends, the buffer cavity is provided with a second threaded hole at the end facing the resonant cavity, the first threaded hole on the resonant cavity is connected to the first external thread, and the second threaded hole on the buffer cavity is connected to the second external thread.

[0022] The outer diameters of the first external thread and the second external thread are different. The inner diameter of the first threaded hole ranges from 4mm to 10mm, and the outer diameter of the first external thread corresponds to the inner diameter of the first threaded hole. The length of the resonant cavity ranges from 40mm to 90mm.

[0023] The parameters and structure of the resonant cavity of this invention can be changed as needed, including but not limited to the length (common lengths are 40mm, 50mm, 60mm, 70mm, 80mm, 90mm), the inner diameter of the resonant cavity (common diameters are 4mm, 6mm, 8mm, 10mm), and the cavity shape (such as cylindrical, ellipsoidal, hyperbolic, etc.). (See reference...) Figure 1 As shown.

[0024] To accommodate resonant cavities of different diameters, the connecting device of this invention provides multiple specifications of threaded connectors, such as outer diameters of 4mm, 6mm, 8mm, and 10mm. The connecting device is hollow internally with threads on the outer ring for mechanical fixing and airtight connection between the buffer cavity and the resonant cavity. Threaded connectors are provided at both ends of the connecting device, one end connecting to the buffer cavity and the other end connecting to the resonant cavity (the outer diameter of this connector matches the inner diameter of the resonant cavity, and is available in 4mm, 6mm, 8mm, and 10mm). The threaded connectors are available in various diameters to accommodate resonant cavities of different diameters. The bottom ends of the threads on both sides of the connecting device have O-rings that match their outer diameters to ensure airtightness at the connection.

[0025] During installation, first lay one side of the buffer cavity flat with the open side facing upwards, and screw the connecting device into the buffer cavity. Then, connect the resonant cavity to be used to the buffer cavity via the connecting device. Next, install the other side of the buffer cavity and tighten the entire structure using the corresponding connecting device threads. During assembly, the O-ring seal is compressed and deformed to form a sealing contact. Users can select the matching resonant cavity model according to parameters such as laser spot size, target gas characteristics, and required acoustic resonance frequency. Replacement takes only a few minutes, is simple to operate, and has a stable structure.

[0026] The working principle of this modular photoacoustic cell with tunable resonant cavity parameters is as follows: The resonant cavity, as the core component of the photoacoustic cell, operates on the principle of the combined effect of photoacoustic and acoustic resonance. It enhances the acoustic signal generated by the absorption of modulated light by the detected gas, thereby improving the system's sensitivity and signal-to-noise ratio. When a modulated laser irradiates gas molecules, if the laser wavelength matches the absorption spectrum of the gas molecules, the gas absorbs the light energy instead of radiatively relaxing, resulting in periodic thermal expansion and contraction, which in turn excites sound waves (pressure waves). This process of converting light into sound is called the photoacoustic effect. The resonant cavity amplifies the weak acoustic signal generated by laser absorption at its resonant frequency, thus achieving highly sensitive detection of gas concentration. The key is to optimize the cavity structure design to match the light modulation frequency with the acoustic modal resonance of the cavity, thereby obtaining the maximum acoustic signal response. The resonant cavity is generally cylindrical, but newer structures such as ellipsoids and hyperbolic shapes are also available. These structures achieve acoustic wave focusing through geometry, significantly improving the acoustic signal intensity and suppressing noise.

[0027] This invention employs a modular structural design, allowing the resonant cavity to be detachably connected to the buffer cavity. This supports the replacement of resonant cavities with different geometric dimensions (such as length, inner diameter, and shape) to adapt to different lasers or detection requirements, providing structural flexibility and performance adjustability. Furthermore, the resonant cavity and buffer cavity are connected via a standardized interface and a reliable connection device, ensuring high replacement efficiency and guaranteeing high repeatability, good coaxiality, and strong airtightness during replacement.

[0028] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the protection scope of the present invention.

Claims

1. A modular photoacoustic cell with tunable resonant cavity parameters, characterized in that, include: It has two buffer chambers, two connecting devices and one resonant cavity. One of the two buffer chambers is equipped with an air inlet and the other with an air outlet. The resonant cavity is connected to one end of a connecting device at each end, and the other end of the connecting device is connected to a buffer cavity. The connecting device connects the resonant cavity and the buffer cavity in a detachable manner. Both connecting devices include a resonant cavity connecting end and a buffer cavity connecting end; the resonant cavity connecting end is connected to one end of the corresponding resonant cavity, and the buffer cavity connecting end is connected to the corresponding buffer cavity; The two connecting devices also include O-rings, and an O-ring is provided at the bottom end of both the resonant cavity connecting end and the buffer cavity connecting end; The two connecting devices are screws. The resonant cavity connecting end is a first external thread, and the buffer cavity connecting end is a second external thread. The resonant cavity has first threaded holes at both ends, and the buffer cavity has a second threaded hole at the end facing the resonant cavity. The first threaded hole on the resonant cavity is connected to the first external thread, and the second threaded hole on the buffer cavity is connected to the second external thread.

2. The modular photoacoustic cell with tunable resonant cavity parameters according to claim 1, characterized in that, The outer diameters of the first external thread and the second external thread are different.

3. The modular photoacoustic cell with tunable resonant cavity parameters according to claim 1, characterized in that, The inner diameter of the first threaded hole ranges from 4mm to 10mm, and the outer diameter of the first external thread corresponds to the inner diameter of the first threaded hole.

4. The modular photoacoustic cell with tunable resonant cavity parameters according to claim 1, characterized in that, The length of the resonant cavity ranges from 40mm to 90mm.

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