Microwave moisture content detection device with exhaust valve module

Abstract

The invention belongs to the technical field of oil product moisture content online detection based on microwave technology, and relates to a microwave moisture content detection device with an exhaust valve module, which comprises a microwave emission source, a microwave resonance unit, a logarithmic detector, a D / A converter, a voltage-controlled oscillator and a microcontroller. The microcontroller controls the D / A converter to input different voltage signals to the voltage-controlled oscillator, the voltage-controlled oscillator generates microwave signals with different frequencies and inputs microwave frequency sweeping signals to the microwave resonance unit through the microwave transmission line, and then the logarithmic detector converts the microwave signals output by the microwave resonance unit into the voltage signals. The microcontroller carries out voltage collection and then transmits collected data to the upper computer through a serial port, and the water content of the oil product is obtained by analyzing and processing the data. The detection device is easy to install, low in cost and capable of detecting the low water content of the oil product on line in real time; the end face of the resonant cavity of the detection device can prevent bubbles from being mixed in the resonant cavity to affect oil product water content measurement; the oil inlet pipeline can primarily discharge bubbles.

Description

Technical Field

[0001] This invention belongs to the field of online detection technology of oil water content based on microwave technology, and specifically relates to a microwave online detection device with an exhaust valve module. Background Technology

[0002] In today's society, the demand for refined oil products is increasing daily, and the requirements for their quality are becoming increasingly stringent. The water content of refined oil products is one of the key indicators for measuring their quality. Refined oil products are mainly obtained through crude oil refining and processing, encompassing categories such as petroleum fuels, solvent oils, and lubricating oils, and their natural water content is extremely low. However, the presence of water in oil products has a significant impact on the operational reliability and safety of various power systems, hydraulic systems, fuel systems, and lubricating oil systems. This is because water accelerates the oxidation and deterioration process of oil products, leading to emulsification of lubricating oils and thus significantly reducing their lubricating performance. Simultaneously, water enhances the corrosive effect of organic acids on metal components, causing equipment rust, and ultimately potentially leading to major mechanical failures such as engine seizure and burnout. Therefore, achieving accurate online detection of oil water content has become a critical link in industrial production processes, crucial for enterprises to eliminate safety hazards and reduce economic losses.

[0003] Furthermore, existing measurement technologies often face a problem in practice: when air bubbles are generated during the storage and transportation of oil, the accuracy and reliability of the measurement are affected. This is because air bubbles dissolved or dispersed in the oil have different dielectric properties than oil and water, which reduces the overall dielectric constant of the mixture. For sensors that rely on changes in dielectric constant for detection, the instrument struggles to effectively distinguish between signal changes caused by moisture or gas, leading to significant deviations in the measurement results that fail to reflect the true state of the oil and affecting online low water content measurements. Therefore, it is necessary to develop a solution for measuring the water content of oil that can effectively overcome or eliminate gas interference.

[0004] Currently, microwave-based water content detection devices are mostly used for detecting high-water-content crude oil. For refined oil products with low water content, traditional methods typically involve analyzing small samples in a laboratory environment, which cannot achieve real-time online dynamic monitoring of water content during production and transportation. Existing online low-water-content oil detection devices generally suffer from insufficient accuracy and sensitivity. Summary of the Invention

[0005] The purpose of this invention is to provide an online detection device for detecting the water content of oil products based on microwave resonant cavity technology, which features an easy-to-install exhaust valve module. The design of the resonant cavity solves the problem of preventing air bubbles from being trapped in the resonant cavity during oil detection, thus enabling accurate online detection of the water content of oil products.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A microwave moisture content detection device with an exhaust valve module is characterized by comprising a microwave transmitting source 1, a microwave resonant unit 2, a microwave receiving device 3, a parameter detection unit 4, and a microcontroller unit 10.

[0008] The microwave transmitter 1 includes a D / A converter 5 and a voltage-controlled oscillator 6; the microwave receiver 3 is a logarithmic detector 7; the parameter detection unit 4 includes a serial port 8 and a host computer 9; and the microcontroller unit 10 is a microcontroller.

[0009] The microwave resonant unit 2 includes a resonant cavity wall 13, an upper pipe 12 and a lower pipe 14 that fit tightly with the resonant cavity wall 13, a sample cavity 17 disposed in the resonant cavity wall 13, a probe, an SMA adapter 20 that is plugged into the probe, and an oil inlet pipe 23 connected to the upper pipe 12, an upper end cap 15 and a lower end cap 16; the oil can enter the sample cavity 17 for holding the oil to be tested through the oil inlet pipe 23 via the upper pipe 12, and the oil inlet pipe 23 is provided with an oil inlet branch 24 and an air bubble venting branch 25.

[0010] The microwave resonant unit 2 is installed in the pipeline that transports oil and is connected to the voltage-controlled oscillator 6 and the logarithmic detector 7 respectively through the microwave transmission line 11.

[0011] The microcontroller is connected to the D / A converter 5 and can control the D / A converter 5 to input different voltage signals to the voltage-controlled oscillator 6. The voltage-controlled oscillator 6 can generate microwave signals of different frequencies and input microwave sweep signals to the microwave resonant unit 2 through the microwave transmission line 11. The logarithmic detector 7 can convert the microwave signals output by the microwave resonant unit 2 into voltage signals. The microcontroller can perform voltage acquisition and display the acquired data on the host computer 9 through the serial port 8. By analyzing and processing the data, parameters such as S-parameter curves and resonant frequencies can be obtained, and thus the water content of the oil can be obtained.

[0012] Furthermore, the upper pipe 12 and lower pipe 14 of the microwave resonant unit 2 are tightly fitted to the resonant cavity wall 13 by four screws 21 and nuts 22 respectively. The upper end cover 15 and lower end cover 16 are tightly fitted to the resonant cavity wall 13 above and below, respectively, forming a semi-open cylindrical resonant cavity.

[0013] Furthermore, the probe is inserted into the inner side of the SMA adapter 20, and there is a gap between the probe and the resonant cavity wall 13 so that they do not directly contact each other. The SMA adapter 20 does not completely pass through the resonant cavity wall 13, and its external microwave transmission line 11 is connected.

[0014] Furthermore, the probe is a dual probe, consisting of a microwave transmitting probe 18 and a microwave receiving probe 19, corresponding to two SMA adapters 20.

[0015] Furthermore, the resonant cavity wall 13, upper pipe 12, and lower pipe 14 are made of metal, with an inner radius of 8 to 13 mm and a thickness of 4 to 8 mm; the probe is made of copper, with a length of 3 to 5 mm and a radius of 0.25 to 0.5 mm, and the probe is located at the longitudinal midpoint of the resonant cavity wall 13, pointing towards the axial center, with the two probes located in the vertical direction of the resonant cavity; the upper end cover 15 and lower end cover 16 are made of metal, with a thickness of 0.8 to 1.5 mm; the height of the resonant cavity is 15 to 25 mm; and the oil inlet pipe 23 is made of metal.

[0016] Furthermore, the probe is a single probe, specifically retaining one of the two probes, capable of independently realizing microwave transmission and microwave reception functions, corresponding to one SMA adapter interface 20.

[0017] Furthermore, the resonant cavity wall 13, upper pipe 12, and lower pipe 14 are made of metal, with an inner radius of 19 to 25 mm and a thickness of 4 to 8 mm; the probe is made of copper, with a length of 3 to 5 mm and a radius of 0.25 to 0.5 mm, and the probe is located at the longitudinal center; the upper end cover 15 and lower end cover 16 are made of metal, with a thickness of 2 to 5 mm; the height of the resonant cavity is 45 to 55 mm; and the oil inlet pipe 23 is made of metal.

[0018] Furthermore, the upper end cover 15 and the lower end cover 16 are closed end covers with openings at locations with low current surface density and near the edges.

[0019] Furthermore, the oil inlet pipe 23 is provided with an arched ramp structure, which rises upward at a slope greater than 15 degrees to form a bulge. The height of the arch is at least 5 times the pipe diameter. The highest point of the arch is connected to the air venting branch 25 and an automatic air venting valve 26 is installed. The oil inlet branch 24 is installed vertically at the top of the straight section in front of the arch.

[0020] Furthermore, the oil inlet branch 24 is installed vertically at the top of the straight section in front of the arch slope.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] The detection equipment of this invention has the advantages of easy installation and low cost, and can complete online real-time detection of low water content in oil. The end face of the resonant cavity of this invention can prevent air bubbles from being trapped in the resonant cavity, which would affect the measurement of water content in oil. The oil inlet pipe of this invention can initially remove air bubbles. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a structural block diagram of the microwave moisture content detection device with an exhaust valve module of the present invention;

[0025] Figure 2 This is a structural diagram of a microwave resonant unit when the resonant cavity is placed horizontally;

[0026] Figure 3 This is a structural diagram of a microwave resonant unit when the resonant cavity is placed vertically;

[0027] Figure 4 This is a top view of the upper cover of the microwave resonator unit when the resonator cavity is placed horizontally;

[0028] Figure 5 The S-parameter curves of a resonant cavity with uniform water content were measured.

[0029] In the diagram: 1. Microwave transmitter 2. Microwave resonant unit 3. Microwave receiver 4. Parameter detection unit 5. D / A converter 6. Voltage-controlled oscillator 7. Logarithmic detector 8. Serial port 9. Host computer 10. Microcontroller unit 11. Microwave transmission line 12. Upper pipe 13. Resonant cavity wall 14. Lower pipe 15. Upper end cover 16. Lower end cover 17. Sample chamber 18. Microwave transmitting probe 19. Microwave receiving probe 20. SMA adapter 21. Screw 22. Nut 23. Oil inlet pipe 24. Oil inlet branch 25. Air venting branch 26. Automatic air vent valve 27. End cover opening. Detailed Implementation

[0030] The present invention will be further described below with reference to embodiments:

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0032] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] like Figure 1 As shown, the microwave moisture content detection device with an exhaust valve module of the present invention includes a microwave emission source 1, a microwave resonant unit 2, a microwave receiving device 3, a parameter detection unit 4, and a microcontroller unit 10.

[0034] The microwave transmitter 1 includes a D / A converter 5 and a voltage-controlled oscillator (VCO) 6. The microwave receiver 3 is a logarithmic detector 7. The parameter detection unit 4 includes a serial port 8 and a host computer (PC) 9. The microcontroller unit 10 is a single-chip microcomputer or a microcontroller (MCU).

[0035] The microwave resonant unit 2 is installed in the pipeline transporting the oil and is connected to the voltage-controlled oscillator 6 and the logarithmic detector 7 via microwave transmission line 11. The microcontroller controls the D / A converter 5 to input different voltage signals to the voltage-controlled oscillator 6. The voltage-controlled oscillator 6 generates microwave signals of different frequencies and inputs microwave sweep signals to the microwave resonant unit 2 via microwave transmission line 11. The logarithmic detector 7 then converts the microwave signals into voltage signals. This output voltage signal, which varies with frequency, reflects the S(S21) parameter of the microwave resonant unit 2. The frequency corresponding to the extreme point (peak or trough) of the S parameter curve is the resonant frequency f. The microcontroller collects the voltage and transmits the collected data to the host computer 9 via serial port 8. The water content of the oil is accurately calculated by detecting parameters such as the resonant frequency f.

[0036] The microwave resonant unit 2 includes a resonant cavity wall 13, an upper pipe 12 that is tightly fitted to the resonant cavity wall 13, a lower pipe 14, an upper end cover 15 located above the resonant cavity wall 13, a lower end cover 16 located below the resonant cavity wall 13, a sample chamber 17 for holding the oil to be tested, a probe, an SMA adapter 20 that does not completely pass through the resonant cavity wall 13, an oil inlet pipe 23, an oil inlet branch 24, and an air bubble venting branch 25.

[0037] The upper pipe 12 and lower pipe 14 are tightly fitted to the resonant cavity wall 13 via four screws 21 and nuts 22, respectively. Above and below the resonant cavity wall 13 are tightly fitted upper end caps 15 and lower end caps 16, respectively. The probe, upper pipe 12, lower pipe 14, resonant cavity wall 13, upper end cap 15, and lower end cap 16 constitute a semi-open cylindrical resonant cavity. The probe is inserted into the inner side of the SMA adapter 20, with a gap between the probe and the resonant cavity wall 13, avoiding direct contact. The SMA adapter 20 is externally connected to a microwave transmission line 11. The probe can be a dual probe or a single probe. A dual probe consists of a microwave transmitting probe 18 and a microwave receiving probe 19, corresponding to two SMA adapters 20. A single probe retains one of the dual probes and can independently perform microwave transmitting and receiving functions, corresponding to one SMA adapter 20.

[0038] Taking a dual-probe design as an example, the resonant cavity wall 13, upper pipe 12, and lower pipe 14 are made of metal with an inner radius of 8 to 13 mm and a thickness of 4 to 8 mm; the probes are made of copper with a length of 3 to 5 mm and a radius of 0.25 to 0.5 mm, and the probes are located at the longitudinal midpoint of the resonant cavity wall 13, pointing towards the axial center, with the two probes located in the vertical orientation of the resonant cavity; the upper end cap 15 and lower end cap 16 are made of metal with a thickness of 0.8 to 5 mm; the height of the resonant cavity is 15 to 25 mm; and the oil inlet pipe 23 is made of metal.

[0039] For a single probe, the resonant cavity wall 13, upper pipe 12, and lower pipe 14 are made of metal, with an inner radius of 19 to 25 mm and a thickness of 4 to 8 mm; the probe is made of copper, with a length of 3 to 5 mm and a radius of 0.25 to 0.5 mm, and the probe is located at the axial center, with the two probes located in the vertical direction of the resonant cavity; the upper end cover 15 and lower end cover 16 are made of metal, with a thickness of 2 to 5 mm; the height of the resonant cavity is 45 to 55 mm; and the oil inlet pipe 23 is made of metal.

[0040] To prevent air bubbles from getting trapped inside the resonant cavity, the upper end cap 15 and the lower end cap 16 are closed end caps with openings near the edge where the current surface density is low. This resonant cavity is designed to measure low water content in oils, and can accurately distinguish between water content in oils classified as grade 10,000. When detecting oils with uneven water content, the resonant cavity is placed at an angle. The upper pipe 12 is connected to the oil inlet pipe 23. The oil inlet pipe 23 has an oil inlet branch 24 and an air bubble venting branch 25. Due to the density difference between gas and oil, the less dense gas will float on the pipe wall. The air bubble venting branch 25 allows any air bubbles to escape if they are present when the oil enters. This branch is used for initial air bubble removal. The upper end cap 15 and the lower end cap 16 are used for secondary air bubble prevention. Eliminating the influence of air bubbles allows the resonant cavity to accurately detect the water content of oils. This device can measure water content as low as one percent.

[0041] When placing the resonant cavity into a pipeline transporting oil, under specific measurement conditions, the pipeline where the resonant cavity is installed is horizontal, and the resonant cavity must also be placed horizontally. Figure 3 As shown. The resonant cavity can be placed tilted or vertically along the axial direction, as... Figure 4 As shown.

[0042] The design of the oil inlet pipe 23 is as follows: 0.5 to 1 meter before the measuring device inlet, the main pipe is designed as an arched, sloping structure, rising upwards at a slope greater than 15 degrees to form a noticeable bulge. The height of the arch apex is at least 5 times the pipe diameter. The measuring device is then connected downwards at the same slope. The highest point of this arch apex is directly connected to the air bubble venting branch 25 and equipped with an automatic air vent valve 26. The oil inlet branch 24 is installed vertically or diagonally downwards at the top of the straight section in front of the arch slope, with vertical insertion being preferred. If space is insufficient, a 45° diagonal downward insertion is used to ensure that air bubbles in the branch enter the main pipe and are directly above the oil flow, floating to the arch apex with the oil. When installing the valve, the vent hole must face upwards.

[0043] Regarding the placement of the resonant cavity in the pipeline transporting oil, the resonant cavity can be placed horizontally or at an angle to the horizontal direction (including placement at a 90-degree vertical direction), and the placement of the resonant cavity can be determined according to the measurement requirements.

[0044] Regarding the orientation of the upper cover 15 of the microwave resonant unit 2, when the resonant cavity is placed horizontally or tilted, for low-viscosity oils, due to their low internal friction resistance, any air bubbles mixed in can quickly escape under the action of buoyancy and cannot remain stably. This causes the air bubbles to float upwards to the resonant cavity wall 13 when mixed with the oil. In this case, the upper cover 15 should be placed with the opening 27 of the cover facing upwards. When the resonant cavity is placed vertically, the upper cover 15 can be placed in any orientation.

[0045] The working principle of the automatic air vent valve 26 is as follows: When bubbles accumulate at a certain level in the arch, the increased gas in the valve chamber causes the stainless steel float to sink. This, in turn, pulls the valve stem downwards via a lever, causing the sealing gasket to leave the valve seat and open the vent hole (3 to 8 mm in diameter). The gas is then expelled under pipeline pressure. After the gas is exhausted, oil enters the valve chamber, and the float rapidly rises within 0.5 seconds due to buoyancy, pushing the valve stem back to its original position, pressing the sealing gasket to close the vent hole and preventing oil leakage. The valve must be installed vertically at the highest point of the arch, with its bottom flush with the center line of the pipeline.

[0046] Working principle:

[0047] The microwave resonant unit 2 is installed in the pipeline for transporting oil. The oil enters the sample chamber 17 in the resonant cavity wall 13 through the oil inlet pipe 23 and the upper pipe 12. The microwave resonant unit 2 is connected to the microwave transmitter 1 and the microwave receiver 3 through the microwave transmission line 11. The microcontroller, microwave transmitter 1, microwave resonant unit 2, microwave receiver 3, and parameter detection unit 4 are connected in sequence. The microcontroller is connected to the microwave transmitter 1 and then to the microwave transmitter probe 18 of the microwave resonant unit 2 through the microwave transmission line 11. The microwave receiver probe 19 is then connected to the receiver 3 through the microwave transmission line 11. The parameter detection unit 4 is connected to the receiver 3 to collect and display data. When the microwave signal is input into the resonant cavity, resonance occurs when the input microwave wavelength matches the size of the resonant cavity. The horizontal axis of the S-parameter corresponds to the output frequency range of the voltage-controlled oscillator 6, reflecting its variation with the resonant frequency of the resonant cavity. The vertical axis represents the amplitude of the S-parameter, i.e., the attenuation or gain of the signal transmitted from the microwave transmitter probe 18 to the microwave receiver probe 19 in the resonant cavity. By sweeping the frequency using the voltage-controlled oscillator 6 and detecting the signal using the logarithmic detector 7, the S-parameter curve of the microwave resonant unit 2 can be measured. The resonant frequency f corresponding to the extreme point (characteristic peak or valley) in the curve can be used as a detection parameter to identify the resonance phenomenon that occurs in the microwave resonant unit 2 at that frequency. Based on the different resonant frequencies f of the resonant cavity, the different water content of the oil can be calculated by the parameter detection unit 4.

[0048] Example 1

[0049] Finite element simulation was performed using HFSS software. Appropriate structural dimensions and power were set, and the dimensions of each resonant cavity were optimized to find a resonant cavity size with a good quality factor and good differentiation of oils with different water contents.

[0050] A dual-probe structure is used in the simulation, taking the measurement of uniform water content (level 10,000) within the range of 0-1‰ as an example. The resonant cavity dimensions are as follows: the inner radius of the resonant cavity wall 13, upper pipe 12, and lower pipe 14 is 11.7 mm, and the outer radius is 16.7 mm; the height of the resonant cavity wall 13 is 22.4 mm, and the height of the upper pipe 12 and lower pipe 14 is 5 mm; the upper end cap 15 and lower end cap 16 have a radius of 11.7 mm and a thickness of 5 mm; the probe is 9.8 mm from the center of the axis, with a length of 9.5 mm and a radius of 0.25 mm; the SMA adapter 20 is 12.8 mm from the center of the axis, with a length of 6.5 mm and a radius of 2.5 mm. At this point, using the resonant cavity to detect the water content of oil at level 10,000 can yield... Figure 5The curve shows the water content on the horizontal axis (X) and the S-parameters on the vertical axis (Y). m1 is the resonant frequency when the oil has zero water content, m2 is the resonant frequency when the oil contains 0.01% water, and so on, with each additional 0.01% water corresponding to a different resonant frequency. The relative permittivity of water is approximately 80, while that of oil is 2.3. Higher water content results in a higher permittivity and a lower resonant frequency in the resonant cavity. This can be determined by... Figure 5 The curve shows that for every 0.01% increase in water content in the oil, the resonant frequency of the resonant cavity decreases by 13MHz. The resonant cavity can accurately distinguish between oils with water content of 0.01% and 0.01%.

[0051] Note that the design of the digital prototype model, the parameter settings for each material, and the selection of the measuring plane described above are merely preferred embodiments and technical principles of the present invention. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A microwave moisture content detection device with an exhaust valve module, characterized in that: It includes a microwave transmitter (1), a microwave resonant unit (2), a microwave receiver (3), a parameter detection unit (4), and a microcontroller unit (10); The microwave transmitter (1) includes a D / A converter (5) and a voltage-controlled oscillator (6); the microwave receiver (3) is a logarithmic detector (7); the parameter detection unit (4) includes a serial port (8) and a host computer (9); and the microcontroller unit (10) is a microcontroller. The microwave resonant unit (2) includes a resonant cavity wall (13), an upper pipe (12) and a lower pipe (14) that fit tightly with the resonant cavity wall (13), a sample cavity (17) disposed in the resonant cavity wall (13), a probe, an SMA adapter (20) that is plugged into the probe, and an oil inlet pipe (23) connected to the upper pipe (12), an upper end cap (15) and a lower end cap (16); the oil can enter the sample cavity (17) for holding the oil to be tested through the oil inlet pipe (23) via the upper pipe (12), and the oil inlet pipe (23) is provided with an oil inlet branch (24) and an air bubble venting branch (25); The microwave resonant unit (2) is installed in the pipeline for conveying oil and is connected to the voltage-controlled oscillator (6) and the logarithmic detector (7) respectively through the microwave transmission line 11; The microcontroller is connected to the D / A converter (5) and can control the D / A converter (5) to input different voltage signals to the voltage-controlled oscillator (6); the voltage-controlled oscillator (6) can generate microwave signals of different frequencies and input microwave sweep signals to the microwave resonant unit (2) through the microwave transmission line (11); the logarithmic detector (7) can convert the microwave signal output by the microwave resonant unit (2) into a voltage signal; the microcontroller can perform voltage acquisition and display the acquired data on the host computer (9) through the serial port (8). By analyzing and processing the data, parameters such as S-parameter curves and resonant frequencies can be obtained, and then the water content of the oil can be obtained.

2. The microwave moisture content detection device with an exhaust valve module according to claim 1, characterized in that: The upper pipe (12) and lower pipe (14) of the microwave resonant unit (2) are tightly fitted to the resonant cavity wall (13) by four screws (21) and nuts (22), respectively. The upper end cover (15) and lower end cover (16) are tightly fitted to the resonant cavity wall (13) above and below, respectively, forming a semi-open cylindrical resonant cavity.

3. The microwave moisture content detection device with an exhaust valve module according to claim 1, characterized in that: The probe is inserted into the inner side of the SMA adapter (20), and there is a gap between the probe and the resonant cavity wall (13) so that they do not directly contact each other. The SMA adapter (20) does not completely pass through the resonant cavity wall (13), and it is connected to the microwave transmission line (11).

4. The microwave moisture content detection device with an exhaust valve module according to claim 1, characterized in that: The probe is a dual probe, consisting of a microwave transmitting probe (18) and a microwave receiving probe (19), corresponding to two SMA adapters (20).

5. A microwave moisture content detection device with an exhaust valve module according to claim 4, characterized in that: The resonant cavity wall (13), upper pipe (12), and lower pipe (14) are made of metal, with an inner radius of 8 to 13 mm and a thickness of 4 to 8 mm; the probe is made of copper, with a length of 3 to 5 mm and a radius of 0.25 to 0.5 mm, and the probe is located at the longitudinal midpoint of the resonant cavity wall (13), pointing towards the axial center, and the two probes are located in the vertical direction of the resonant cavity; the upper end cover (15) and lower end cover (16) are made of metal, with a thickness of 0.8 to 5 mm; the height of the resonant cavity is 15 to 25 mm; the oil inlet pipe (23) is made of metal.

6. The microwave moisture content detection device with an exhaust valve module according to claim 1, characterized in that: The probe is a single probe, specifically one of the two probes, capable of independently performing microwave transmission and reception functions, corresponding to an SMA adapter (20).

7. A microwave moisture content detection device with an exhaust valve module according to claim 6, characterized in that: The resonant cavity wall (13), upper pipe (12), and lower pipe (14) are made of metal, with an inner radius of 19 to 25 mm and a thickness of 4 to 8 mm; the probe is made of copper, with a length of 3 to 5 mm and a radius of 0.25 to 0.5 mm, and the probe is located at the longitudinal center; the upper end cap (15) and lower end cap (16) are made of metal, with a thickness of 2 to 5 mm; the height of the resonant cavity is 45 to 55 mm; and the oil inlet pipe (23) is made of metal.

8. A microwave moisture content detection device with an exhaust valve module according to claim 1, characterized in that: The upper end cover (15) and the lower end cover (16) are closed end covers with openings at places with low surface current density and near the edge.

9. A microwave moisture content detection device with an exhaust valve module according to claim 1, characterized in that: The oil inlet pipe (23) is equipped with an arched ramp structure, which rises upward at a slope greater than 15 degrees to form a bulge. The height of the arch is at least 5 times the diameter of the pipe. The highest point of the arch is connected to the air venting branch (25) and an automatic air venting valve (26) is installed. The oil inlet branch (24) is installed vertically at the top of the straight section in front of the arch.

10. A microwave moisture content detection device with an exhaust valve module according to claim 9, characterized in that: The oil inlet branch (24) is installed vertically at the top of the straight section in front of the arch slope.

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