Liquid input infrared spectrum gas cell for detecting methanol in baijiu

Abstract

The utility model belongs to the field of spectral detection discloses a kind of liquid input infrared spectrum gas cell for methanol detection in liquor, including pipe body, heating layer body and injection assembly, pipe body includes pipe body and the two infrared transmission glass sheet of pipe body both ends shielding, and pipe body's peripheral surface has sample injection port, heating layer body is fully pasted and set in the outer peripheral surface of pipe body, heating wire is embedded in heating layer body, and heating wire is connected with the power supply device outside, injection assembly includes injection septum and sample injection needle, injection septum is set in sample injection port, so that injection septum can be detachably closed pipe body relative to outside;Sample injection needle has sample containing part and sample injection needle part, sample containing part contains predetermined amount of liquor sample, sample injection needle is inserted into injection septum, so that the free end of sample injection needle part enters pipe body.

Description

Technical Field

[0001] This utility model belongs to the field of spectral detection and discloses a liquid-input infrared spectral gas cell for detecting methanol in liquor. Background Technology

[0002] Baijiu (Chinese liquor) is not only an important part of traditional Chinese food culture, but also carries profound historical significance and national sentiment. During its brewing process, the degradation of pectin in the raw materials under high temperatures or enzymatic action typically produces a certain amount of methanol. Methanol is a neurotoxic and harmful component; excessive intake can lead to poisoning, and in severe cases, even vision impairment or permanent blindness. However, the risk of methanol poisoning does not only stem from natural formation. Some illegal manufacturers, seeking illicit economic gains, adulterate baijiu by substituting methanol for alcohol, posing a serious threat to consumers' lives and health. Against this backdrop, developing efficient and accurate methanol detection technology is not only crucial for protecting public health, but also helps strengthen industry supervision, regulate market order, and safeguard the reputation and sustainable development of the baijiu industry.

[0003] Currently, there are various methods for detecting methanol in alcoholic beverages. For example, gas chromatography-flame ionization detection (GC-FID), fuchsin colorimetric method, high-performance liquid chromatography (HPLC) and its ultraviolet detection variant (HPLC-UV / Vis), while possessing good selectivity and sensitivity, generally suffer from significant drawbacks such as expensive equipment, long analysis time (relying on chromatographic separation or multiple manual steps), complex sample pretreatment (often requiring distillation, derivatization, or extraction), and high dependence on professional operators. These limitations restrict their widespread application in grassroots supervision, on-site screening, and online quality control in enterprises. Therefore, there is an urgent need to develop a new, efficient, rapid, accurate, and convenient method for the accurate and rapid detection of methanol in baijiu (Chinese liquor) to ensure food safety for the public.

[0004] Infrared gas cell spectroscopy offers advantages such as being non-destructive, rapid, and requiring no complex pretreatment, providing effective information for the detection of methanol in baijiu (Chinese liquor). However, since the methanol content in baijiu is typically low, its infrared absorption signal is weak and easily interfered with by structurally similar ethanol, making the sensitivity and selectivity of conventional infrared detection methods insufficient. Infrared gas cells, through extended optical path design, can significantly improve the detection sensitivity of trace components. In the gaseous state, the characteristic absorption peaks of methanol and ethanol are sharper and more clearly separated, with significantly reduced interference, making them suitable for highly selective analysis.

[0005] Existing infrared gas cells mostly employ a fixed tubing structure, primarily suitable for pure gas samples. For volatile liquid samples such as spirits, ... Figure 1As shown, an external liquid / gas conversion device is usually required to convert a predetermined amount of liquor sample into a liquid / gas state to ensure complete vaporization. The sample is then transferred through a long pipeline and valve assembly to an infrared gas cell for infrared irradiation. This process causes significant sample distortion: on the one hand, the dead volume of the pipeline and the valve cavity have a stronger adsorption force on polar molecules (such as methanol) than on non-polar molecules, leading to an imbalance in the component ratio; on the other hand, the shedding of metal / rubber particles and the infiltration of ambient gases into the sample stream during the transfer cause the gas to deviate from its original composition and introduce foreign contaminants, ultimately causing the object to be detected to completely deviate from the true matrix.

[0006] More importantly, after repeated opening and closing or long-term use, the pure glass sample introduction structure of traditional gas cells can lead to stress concentration in certain areas due to thermal expansion and contraction. In addition, the gradual expansion of tiny surface defects can eventually cause the seal to fail and cause leakage. Once a leak occurs, the entire structure often needs to be replaced, resulting in high maintenance costs. Utility Model Content

[0007] To address the shortcomings of existing technologies, this invention provides a liquid-input infrared spectral gas cell for methanol detection in baijiu (Chinese liquor). It can detect methanol in baijiu without the need for external liquid / gas conversion devices and pipelines, thus greatly avoiding distortion of baijiu samples. Furthermore, it has a simple structure and low maintenance costs.

[0008] To achieve the above objectives, the present invention provides the following technical solution: An infrared spectral gas cell with liquid input for methanol detection in baijiu (Chinese liquor) is characterized by comprising: a tube body, including a tube body with openings at both ends and two infrared-transmitting glass slides that close and block the openings at both ends of the tube body, and a sample injection port on the peripheral surface of the tube body; a heating layer, fully attached to the outer peripheral surface of the tube body, wherein a heating wire is embedded inside the heating layer and the heating wire is connected to an external power supply device; the heating layer has a through hole corresponding to the sample injection port; and an injection assembly, including an injection septum and a sample injection needle, wherein the injection septum is disposed at the sample injection port, thereby detachably sealing the tube body relative to the outside; the sample injection needle has a sample receiving part and a sample injection needle part that are interconnected, the sample receiving part containing a predetermined amount of baijiu sample, and the sample injection needle being insertable into the injection septum, so that the free end of the sample injection needle part enters the tube body.

[0009] Preferably, the pipe body is equipped with a pressure sensor, which detects the real-time internal pressure of the pipe body. Preferably, the present invention further includes an outer sheath assembly, comprising a heat insulation layer, an insulating layer, and a heating layer sequentially fitted from the outside to the inside. The insulating layer insulates the heating layer relative to the heat insulation layer, and the heat insulation layer insulates the insulating layer relative to the outside. Furthermore, the heat insulation layer, the insulating layer, and the heating layer all have through holes corresponding to the sample injection port.

[0010] Preferably, the present invention also includes...

[0011] Preferably, the fixed frame includes a pair of end-sealing plates, which are correspondingly closed at both ends of the tube body openings and are connected and fixed to the tube body by bolts. The end-sealing plates have light-transmitting stepped through holes with light-transmitting stepped surfaces facing the inside of the tube body. A pair of infrared-transmitting sheets are correspondingly adhered to the pair of light-transmitting stepped surfaces. Preferably, the tube body is equipped with a temperature sensor, which detects the real-time internal temperature of the tube body.

[0012] Preferably, the injection assembly further includes an injection conduit, one end of which passes through and is disposed at the sample injection port, and an injection septum is detachably closed at the other end. Compared with the prior art, the beneficial effects of this utility model are: 1. The liquid-input infrared spectral gas cell for methanol detection in baijiu (Chinese liquor) of this invention includes a tube body, a heating layer, and an injection assembly. The tube body includes a tube body and two infrared-transmitting glass slides that block both ends of the tube body. A sample injection port is located on the circumferential surface of the tube body. The heating layer is fully attached to the outer circumferential surface of the tube body, and a heating wire is embedded inside the heating layer and connected to an external power supply device. The injection assembly includes an injection septum and a sample injection needle. The injection septum is located at the sample injection port, thereby detachably sealing the tube body relative to the outside. The sample injection needle has a sample receiving portion and a sample injection needle portion. The sample receiving portion contains a predetermined amount of baijiu sample, and the sample injection needle is retractable. The sample injection needle is inserted into the tube body through a septum, allowing the free end of the needle to enter the tube body. When detecting methanol in baijiu (Chinese liquor), the sample injection needle containing a predetermined amount of baijiu sample is first inserted into the septum, and then the predetermined amount of baijiu sample is injected into the tube body. Next, the tube body is heated by energizing a heating wire, causing the predetermined amount of baijiu sample to evaporate into a gaseous state. Then, infrared light is irradiated into the tube body from the outside of an infrared-transmitting glass slide, thus achieving infrared detection of methanol in the baijiu. Therefore, this invention can complete the detection of methanol in baijiu without the need for an external liquid / gas conversion device or pipeline connection, greatly avoiding distortion of the baijiu sample. Furthermore, it has a simple structure and low maintenance costs.

[0013] 2. Because the tube body of this utility model is equipped with a pressure sensor, which detects the real-time internal pressure of the tube body, this utility model uses whether the fluctuation of the feedback value of the pressure sensor within a predetermined time is less than a predetermined fluctuation threshold as a criterion for judging whether the liquor in the tube body has been completely evaporated into a gaseous state, thereby improving the accuracy of methanol detection results for liquor samples.

[0014] 3. Because this utility model also includes an outer sheath assembly, comprising a heat insulation layer, an insulating layer, and a heating layer sequentially fitted from the outside to the inside, the insulating layer insulates the heating layer relative to the heat insulation layer, and the heat insulation layer insulates the insulating layer relative to the outside. Furthermore, the heat insulation layer, the insulating layer, and the heating layer all have through holes corresponding to the sample injection port. Therefore, during the testing process, the outer surface of this utility model is guaranteed to be free from leakage and the risk of burns due to temperature, thus ensuring the safety of the device. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of an existing infrared gas cell.

[0016] Figure 2 This is a side view of the liquid-input infrared spectral gas cell for methanol detection in baijiu (Chinese liquor) according to an embodiment of the present invention.

[0017] Figure 3 This is a top view (without the outer casing assembly) of the liquid-input infrared spectral gas cell for methanol detection in baijiu, according to an embodiment of the present invention.

[0018] Figure 4 This is a three-dimensional schematic diagram of an infrared spectral gas cell with liquid input for methanol detection in baijiu, as an embodiment of the present invention.

[0019] Figure 5 for Figure 4 A cross-sectional schematic diagram (sketching of the internal pressure display, internal temperature display, and injection components).

[0020] In the diagram: 100, Infrared spectral gas cell for liquid input in the detection of methanol in liquor; 10, Tube body; 11, Tube body; 111, Sample injection port; 12, Infrared transmitting glass slide; P1, Internal pressure display screen; P2, Internal temperature display screen; 20, Tube outer sheath assembly; 21, Heat insulation layer; 22, Insulation layer; 23, Heating layer; 30, Fixing frame; 31, End sealing plate; 311, Transparent stepped through hole; 311a, Transparent stepped surface; 32, Connecting bolt; 40, Injection assembly; 41, Injection pipe; 41a, Sealing layer; 42, Injection septum; 43, Sample injection needle; 431, Sample receiving part; 432, Sample injection needle part. Detailed Implementation

[0021] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate the liquid input infrared spectral gas cell for methanol detection in baijiu of this utility model. It should be noted that the description of these embodiments is for the purpose of helping to understand this utility model, but does not constitute a limitation on this utility model.

[0022] like Figures 2 to 5 As shown, the liquid input infrared spectral gas cell 100 for methanol detection in baijiu in this embodiment includes a tube body 10, a sensor assembly, a tube outer cladding assembly 20, a fixing frame 30, and an injection assembly 40. The tube body 10 includes a tube body 11 and two infrared-transmitting glass slides 12.

[0023] The tube body 11 has openings at both ends, and a sample injection port 111 is provided on the circumferential surface of the tube body 11. Specifically, the tube body 11 is a hollow cylinder. In this embodiment, the length of the tube body 11 is 10 cm to 20 cm and the diameter is 2 cm to 4 cm.

[0024] Two infrared transmitting glass plates 12 seal and block the openings at both ends of the tube body 11. Specifically, the infrared transmitting glass plates 12 are made of materials with high infrared transmittance and can ensure that the two ends of the tube body 11 are sealed. In this embodiment, the infrared transmitting glass plates 12 are CaF2 or ZnSe.

[0025] The sensor assembly includes a pressure sensor (not shown in the figures) and a temperature sensor (not shown in the figures). In this embodiment, the pressure sensor is a diffused silicon pressure sensor with a maximum operating temperature of 70°C; the temperature sensor is a thermocouple placed inside the tube body 11.

[0026] Both the pressure sensor and the temperature sensor are located inside the tube body 11. The pressure sensor is attached to the inner wall of the tube body 11 and is used to detect the real-time internal pressure of the tube body 11. The temperature sensor detects the real-time internal temperature of the tube body. Specifically, during the methanol detection test in baijiu, the highest temperature of the tube body 11 is 70℃. The pressure sensor and the temperature sensor are respectively connected to the internal pressure display screen P1 and the internal temperature display screen P2 on the outside of the tube body 11 so that the operator can read the internal pressure and internal temperature of the tube body 11 in real time from the outside.

[0027] The outer sheath assembly 20 includes a heat insulation layer 21, an insulating layer 22, and a heating layer 23 that are sequentially fitted from the outside to the inside.

[0028] The heating layer 23 is fully attached to the outer circumferential surface of the tube body 11. A heating wire (not shown in the figure) is embedded inside the heating layer 23 and is connected to an external power supply device (not shown in the figure). The heating layer 23 has a through hole (not shown in the figure) corresponding to the sample injection port 111. In this embodiment, the heating layer 23 is a rare earth thick film heating film.

[0029] The insulating layer 22 insulates the heating layer 23 relative to the heat insulation layer 21, and the heat insulation layer 21 insulates the insulating layer 22 relative to the outside. The heat insulation layer 21, the insulating layer 22, and the heating layer 23 all have through holes corresponding to the sample injection port, so that the sample injection port 111 is exposed to the outside through the tube outer sheath assembly 20.

[0030] The fixed frame 30 includes a pair of end sealing plates 31, which are respectively closed at both ends of the pipe body 11, and the pair of end sealing plates are connected and fixed to the pipe body 11 by connecting bolts 32.

[0031] The end sealing plate 31 has a light-transmitting stepped through hole 311, and the light-transmitting stepped through hole 311 has a light-transmitting stepped surface 311a facing the inside of the tube body 11. A pair of infrared-transmitting sheets 12 are correspondingly attached to the pair of light-transmitting stepped surfaces 311a. In this embodiment, the infrared-transmitting sheets 12 are attached to the light-transmitting stepped surfaces 311a with sealant, thereby achieving the sealing of the end of the tube body 11 by the infrared-transmitting sheets 12.

[0032] The injection assembly 40 includes an injection conduit 41, an injection septum 42, and a sample injection needle 43.

[0033] One end of the injection conduit 41 passes through and is connected to the sample injection port 111, and the injection septum 42 is detachably sealed at the other end. Specifically, there is a sealant layer 41a between the injection conduit 41 and the sample injection port 111. The injection septum 42 is glued to the injection conduit 41 with sealant, thereby achieving a sealed connection between the injection conduit 41, the sample injection port 111, and the injection conduit 41 and the injection septum 42. Since the injection septum 42 can be easily peeled off from the end of the injection conduit 41, the injection septum 42 detachably seals the tube body 41 relative to the outside.

[0034] The sample injection needle 43 has a sample receiving part 431 and a sample injection needle part 432 that are interconnected. The sample receiving part 431 contains a predetermined amount of liquor sample. The sample injection needle 43 can be inserted into the injection septum 42, so that the free end of the sample injection needle part 432 enters the tube body 11.

[0035] The detection process of the liquid-input infrared spectral gas cell 100 for detecting methanol in baijiu is described below with reference to specific embodiments: First, a predetermined amount of liquid liquor sample is extracted from the outside of the tube body 11 using the sample injection needle 43. Then, the sample injection needle containing the predetermined amount of liquor sample is inserted into the injection septum 42, and the predetermined amount of liquor sample is injected into the tube body 11 through the free end of the sample injection needle 432. Next, the heating wire of the heating layer 23 is energized by an external power supply device to heat the tube body 11, causing the predetermined amount of liquor sample to evaporate into a gaseous state. Specifically, during the heating process, the operator observes the internal pressure display screen P1 in real time. When the internal pressure fluctuation of the tube body 11 is less than a predetermined fluctuation threshold, the internal pressure of the tube body 11 is considered to be basically stable, meaning that the liquid liquor sample in the tube body 11 is at this point... After all the liquid has evaporated into a gaseous state, infrared spectral detection can be performed. Then, the outside of the infrared-transmitting glass slide is irradiated into the tube body to achieve infrared detection of methanol in the liquor. During the detection process, the operator should observe the internal temperature display screen P2 in real time to prevent the internal temperature of the tube body 11 from exceeding the predetermined temperature range of the detection process. Specifically, there are two sample injection ports 111, but only one is used for methanol detection in liquor. After the detection is completed, nitrogen is introduced into the two sample injection ports 111 of the tube body 11 and nitrogen is discharged from the two sample injection ports 111 respectively. The nitrogen circulating in the tube body 11 carries the residual gas (gaseous liquor sample) from the inside of the tube body 11 to the outside.

[0036] The above embodiments are preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Various modifications or variations that can be made by those skilled in the art without creative effort within the scope of the appended claims are still within the scope of protection of this patent.

Claims

1. A liquid-input infrared spectral gas cell for detecting methanol in baijiu (Chinese liquor), characterized in that, include: The tube body includes a tube body with openings at both ends and two infrared-transmitting glass slides that close and block the openings at both ends of the tube body, and the tube body has a sample injection port on its peripheral surface. A heating layer is fully attached to the outer circumferential surface of the tube body. A heating wire is embedded inside the heating layer and is connected to an external power supply device. The heating layer has a through hole corresponding to the sample injection port. An injection assembly includes an injection septum and a sample injection needle. The injection septum is disposed at the sample injection port, thereby detachably sealing the tube body relative to the outside. The sample injection needle has a sample receiving portion and a sample injection needle portion that are in communication with each other. The sample receiving portion contains a predetermined amount of liquor sample. The sample injection needle can be inserted into the injection septum, so that the free end of the sample injection needle portion enters the tube body.

2. The liquid-input infrared spectral gas cell for methanol detection in baijiu according to claim 1, characterized in that: in, The pipe body is equipped with a pressure sensor, which detects the real-time internal pressure of the pipe body.

3. The liquid-input infrared spectral gas cell for methanol detection in baijiu according to claim 1 or 2, characterized in that, Also includes: The tube outer sheath assembly includes a heat insulation layer, an insulating layer, and a heating layer that are sequentially fitted from the outside to the inside. The insulating layer insulates the heating layer relative to the heat insulation layer, and the heat insulation layer insulates the insulating layer relative to the outside. Each of the heat insulation layer, the insulating layer, and the heating layer has a through hole corresponding to the sample injection port.

4. The liquid-input infrared spectral gas cell for methanol detection in baijiu according to claim 1, characterized in that, Also includes: The fixed frame includes a pair of end-sealing plates, which are respectively disposed at both ends of the pipe body and are fixed to the pipe body by bolts. The end-sealing plate has a light-transmitting stepped through-hole, which has a light-transmitting stepped surface facing the inside of the tube body, and a pair of infrared-transmitting sheets are correspondingly attached to the pair of light-transmitting stepped surfaces.

5. The liquid-input infrared spectral gas cell for methanol detection in baijiu according to claim 1, characterized in that: in, The tube body is equipped with a temperature sensor, which detects the real-time internal temperature of the tube body.

6. The liquid-input infrared spectral gas cell for methanol detection in baijiu according to claim 1, characterized in that: in, The injection assembly also includes an injection conduit, one end of which passes through and is connected to the sample injection port, and the injection septum is detachably closed at the other end.

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