Automatic drainage structure for internal pipeline of differential pressure sensor

Abstract

The invention discloses an automatic drainage structure for an internal pipeline of a differential pressure sensor, and relates to the technical field of sensors, the structure comprises a shell member, and an equipment cabin and a drainage cabin are sequentially stacked and communicated in the shell member; the interior of the drainage cabin is divided into a plurality of pressure sensing spaces; the pressure difference sensing element is mounted in the equipment cabin, and the pressure sensing end faces the drainage cabin to measure the air pressure of the pressure sensing space; a plurality of air inlet pipes are arranged on one side of the drainage cabin and are communicated with the pressure sensing spaces respectively; a drainage slope inclining from the drainage cabin to the air inlet pipe is arranged in the side, bordering the air inlet pipe, of the drainage cabin and used for promoting condensate water to be drained along the drainage slope due to the gravity. The volume of each pressure sensing space is larger than that of the air inlet pipe connected with the pressure sensing space, so that pressure difference is formed by air pressure change to assist drainage; according to the structure, under the condition that the installation size of the sensor is not changed, efficient drainage of condensate water is achieved, the reliability in the low-temperature and complex environment is improved, pipeline blockage is avoided, and the measurement precision and the service life are guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensors, in particular to an automatic drainage structure for internal pipeline of a differential pressure sensor. BACKGROUND

[0002] As a key component in the modern automobile engine emission control system, the differential pressure sensor is widely used in the particulate filter (GPF / DPF) and low-pressure exhaust gas recirculation (EGR) system. Its basic function is to calculate the degree of blockage of the particulate filter or the size of the gas flow by measuring the gas pressure difference between the front and rear pipelines, thereby providing a reliable reference signal for the engine control unit (ECU). Since the measurement result is directly related to the accuracy of tail gas emission control and the stability of engine operation, the reliability of the differential pressure sensor is particularly important.

[0003] In actual working conditions, the differential pressure sensor needs to directly contact the automobile exhaust; the exhaust composition is complex, containing high-temperature exhaust gas and a large amount of water vapor; when the exhaust gas encounters cold in the sensor cavity or pipeline, the water vapor will condense into condensed water; if the condensed water cannot be drained in time, it will often accumulate in the pipeline or cavity, causing partial or complete blockage of the airflow passage, thereby causing the sensor to output abnormal signals. Especially in cold regions, the water may even freeze in the pipeline or cavity, further causing permanent damage to the sensor.

[0004] Therefore, how to avoid the interference of condensed water on the performance of the sensor has become a long-standing technical challenge in the industry; in the prior art, in order to reduce the influence of condensed water, the pressure cavity design is usually optimized or the condensed water is allowed to drain naturally by relying on its own weight; however, such solutions have certain limitations.

[0005] Firstly, the efficiency of gravity drainage is low, and in the case of small exhaust flow rate or limited pipeline form, the condensed water may be retained in the low part of the sensor and difficult to drain in time; secondly, in extreme environments (such as low temperature, snow and saline-alkali environment), the condensed water is easy to freeze or form blockage in the drainage path, so that the sensor pipeline cannot be kept unobstructed; thirdly, in order to match the installation space of the whole vehicle, the size of the sensor body is usually limited, and the traditional structure is difficult to consider strength, reliability and high-efficiency drainage capacity in the limited space.

[0006] In summary, it is found that the prior art at least has the following technical problems: The existing differential pressure sensor has the technical problems of low drainage efficiency, easy freezing of condensed water in the internal pipeline in low temperature environment, difficulty in realizing efficient and adaptive drainage in limited installation size, and insufficient drainage reliability. SUMMARY

[0007] The differential pressure sensor internal pipeline automatic drainage structure aims to solve the problems of low drainage efficiency, condensate water easy to freeze in the internal pipeline at low temperature, difficulty in realizing efficient and adaptive drainage in limited installation size, and insufficient drainage reliability.

[0008] The preferred technical solutions in the various technical solutions provided by the present application can produce the following technical effects.

[0009] To solve the above technical problems, the present application provides the following technical solutions: The differential pressure sensor internal pipeline automatic drainage structure comprises a shell for accommodating a differential pressure sensing element to be matched; a device cabin and a drainage cabin are sequentially stacked and communicated in the shell; the differential pressure sensing element is installed in the device cabin, and a pressure sensing end of the differential pressure sensing element faces the drainage cabin; a plurality of pressure sensing spaces are separated in the drainage cabin; a plurality of pressure sensing ends of the differential pressure sensing element correspond to the plurality of pressure sensing spaces respectively, and sense the air pressure of the respective pressure sensing spaces; a plurality of air inlet pipes are arranged on one side of the drainage cabin, and the plurality of air inlet pipes are communicated with the plurality of pressure sensing spaces respectively; a drainage inclined surface is arranged in the position where the drainage cabin and the air inlet pipe are adjacent, and the drainage inclined surface is inclined from the drainage cabin to the air inlet pipe, so as to promote the condensate water condensed on the inner wall of the pressure sensing space to be discharged from the air inlet pipe to the outside of the shell by gravity; the volume of a single pressure sensing space is greater than the volume of the connected air inlet pipe, so as to form a pressure difference self-drainage by using the air pressure change of the pressure sensing space.

[0010] In one embodiment, when the air pressure in the pressure sensing space changes, the expansion or contraction amount of the gas in the pressure sensing space exceeds the volume of the air inlet pipe, so as to push the water film formed by the condensate water in the air inlet pipe, and the condensate water entering the air inlet pipe from the pressure sensing space is discharged; the condensate water forms a drainage path from the pressure sensing space to the air inlet pipe by gravity self-drainage in the pressure sensing space of the drainage cabin, breaks the water film formed by the condensate water in the air inlet pipe by pressure difference self-drainage, and promotes the condensate water to be efficiently discharged from the pressure sensing space, the air inlet pipe and the shell.

[0011] In one embodiment, the inner wall of the pressure sensing space and the position where the drainage cabin and the air inlet pipe are connected are uniformly provided with a transition round corner or a transition chamfer, so as to improve the smoothness of the condensate water sliding on the inner wall of the drainage cabin to the air inlet pipe and being discharged to the outside of the shell.

[0012] In one embodiment, a hydrophobic layer is sprayed on the inner wall of the pressure sensing space.

[0013] In one embodiment, the hydrophobic layer is a Teflon coating or a polysiloxane coating or a fluorosilicone modified nanosilica composite coating or a carbon fiber silicone resin composite coating.

[0014] In one embodiment, the inner wall of the air inlet pipe is roughened to increase the roughness of the inner wall of the air inlet pipe and reduce the formation of a water film on the inner wall of the air inlet pipe that closes the inner cross section of the air inlet pipe.

[0015] The beneficial effects of the present application are as follows: The differential pressure sensor internal pipeline automatic drainage structure provided improves the overall reliability and adaptability by arranging a device cabin and a drainage cabin that are sequentially stacked and communicated inside the shell member, so that the differential pressure sensing element and the drainage function module are spatially separated and functionally complementary.

[0016] Specifically: (1) The drainage efficiency is significantly improved; multiple pressure sensing spaces are formed by partitioning the inside of the drainage cabin, and multiple air inlet pipes are arranged in communication with the pressure sensing spaces on one side, and an inclined drainage slope is designed at the inner junction of the air inlet pipes and the drainage cabin, so that the condensed water can be naturally collected and quickly drained along the slope under the action of gravity, significantly improving the efficiency of gravity self-drainage and avoiding the retention of condensed water in the cabin and pipeline.

[0017] (2) Enhance the anti-blocking ability in low temperature environment; the volume of a single pressure sensing space is designed to be larger than the volume of the connected air inlet pipe, and the pressure difference between the pressure sensing space and the air inlet pipe is formed by using the change of air pressure, thereby generating a driving effect to accelerate the outward drainage of condensed water; even in a low temperature environment, the freezing tendency of condensed water is strong, and this structure can reduce the risk of freezing and blocking through the combined action of the drainage slope and the pressure difference, ensuring the continuous and reliable operation of the sensor.

[0018] (3) Strong adaptability and installation compatibility; this technical solution realizes drainage function upgrade through internal cavity structure optimization without changing the overall size of the sensor, which not only ensures the compatibility with the existing vehicle installation conditions, but also avoids the problem of volume expansion caused by structural addition, and has high generalizability.

[0019] (4) Improve system reliability and durability; the stacked layout of the drainage cabin and the device cabin effectively isolates the sensor elements from the condensed water, and the device cabin is arranged below the drainage cabin, so that the condensed water cannot enter the device cabin above it driven by gravity, avoiding direct contact or intrusion of the condensed water into the sensitive area of the differential pressure sensing element, and fundamentally improving the reliability and service life of the sensor in extreme working conditions.

[0020] In summary, the technical scheme solves the problems of low drainage efficiency of the differential pressure sensor, freezing and blocking of condensate water at low temperature, and limited installation space, and realizes efficient and self-adaptive drainage design, thereby improving the safety, stability and market applicability of the product while ensuring accurate measurement. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical scheme of the present application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0022] Figure 1 is a schematic diagram of the shaft measurement structure of the differential pressure sensor of the present application; Figure 2 is a schematic diagram of the cross-sectional structure of the automatic drainage structure of the internal pipeline of the differential pressure sensor of the present application; Figure 3 is an assembly schematic diagram of the cover plate, support frame, waterproof sealing glue, differential pressure sensing element and data transmission terminal of the present application.

[0023] Among them, the reference signs are as follows: 1, housing; 11, mounting ear hole; 2, equipment cabin; 21, maintenance window; 3, drainage cabin; 31, pressure sensing space; 4, differential pressure sensing element; 41, pressure sensing end; 5, air inlet pipe; 51, air inlet end; 52, drainage slope; 6, cover plate; 61, pressure relief hole; 62, pressure relief head; 7, support frame; 71, waterproof sealing glue; 8, electrical connection port; 81, data transmission terminal; 9, differential pressure sensor. DETAILED DESCRIPTION

[0024] The technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application.

[0025] This specific embodiment provides an automatic drainage structure for the internal pipeline of a differential pressure sensor. The drainage structure includes an outer casing, within which an equipment compartment and a drainage compartment are stacked and interconnected. The drainage compartment is divided into multiple pressure sensing spaces. A differential pressure sensing element is installed in the equipment compartment, with its pressure sensing end facing the drainage compartment to measure the air pressure in the pressure sensing space. Multiple air inlet pipes are provided on one side of the drainage compartment, each connected to a pressure sensing space. A drainage slope, inclined from the drainage compartment towards the air inlet pipe, is provided on the side where the drainage compartment meets the air inlet pipe to facilitate the discharge of condensate by gravity along the drainage slope. The volume of a single pressure sensing space is larger than the volume of its connected air inlet pipe, utilizing pressure changes to create a differential pressure to assist drainage. This structure achieves efficient condensate drainage while maintaining the sensor's installation dimensions, improving the reliability of the differential pressure sensor in low-temperature and complex environments, preventing pipeline blockage, and ensuring measurement accuracy and service life. It effectively solves the technical problems of existing differential pressure sensors, such as low drainage efficiency, easy freezing of condensate inside at low temperatures, difficulty in achieving efficient and adaptive drainage within limited installation dimensions, and insufficient drainage reliability.

[0026] The first implementation of an automatic drainage structure for the internal piping of a differential pressure sensor, for example Figures 1 to 3 As shown, the device includes a housing 1 for accommodating a differential pressure sensing element 4 to be matched; the housing 1 contains a stacked and interconnected equipment compartment 2 and a drainage compartment 3, the differential pressure sensing element 4 is installed in the equipment compartment 2, and the pressure sensing end 41 of the differential pressure sensing element 4 faces the drainage compartment 3; the drainage compartment 3 is divided into multiple pressure sensing spaces 31, and the multiple pressure sensing ends 41 of the differential pressure sensing element 4 correspond to the multiple pressure sensing spaces 31 respectively, and sense the air pressure of each pressure sensing space 31; multiple air inlet pipes 5 are provided on one side of the drainage compartment 3, and the multiple air inlet pipes 5 are respectively connected to the multiple pressure sensing spaces 31; a drainage slope 52 is provided on the side of the drainage compartment 3 where it meets the air inlet pipes 5, which is used to promote the condensate water condensed on the inner wall of the pressure sensing space 31 to be discharged from the air inlet pipes 5 to the outside of the housing 1 by gravity drainage; the volume of a single pressure sensing space 31 is larger than the volume of the connected air inlet pipe 5, which is used to form differential pressure drainage by utilizing the air pressure change of the pressure sensing space 31.

[0027] The air intake pipe 5 is offset and connected to the pressure sensing space 31 of the drainage chamber 3, so that one side of the air intake pipe 5 is close to the inner wall of the pressure sensing space 31, and the other side of the air intake pipe 5 is far away from the inner wall of the pressure sensing space 31. A drainage slope 52 is provided between the air intake pipe 5 and the inner wall of the pressure sensing space 31, which is inclined from the drainage chamber 3 to the air intake pipe 5 from top to bottom.

[0028] The automatic drainage structure of the internal pipeline of the differential pressure sensor sets up a sequentially stacked and interconnected equipment compartment 2 and drainage compartment 3 inside the outer casing 1, so that the differential pressure sensing element 4 and the drainage function module can be spatially separated and functionally complementary, thereby improving the overall reliability and adaptability.

[0029] Specifically, the drainage efficiency is significantly improved: the drainage chamber 3 is divided into multiple pressure sensing spaces 31, and multiple air inlet pipes 5 are arranged on one side of them and connected to them. An inclined drainage slope 52 is designed at the junction of the air inlet pipe 5 and the interior of the drainage chamber 3, so that the condensate can naturally collect along the slope and be discharged quickly under the action of gravity, which significantly improves the efficiency of gravity self-drainage and avoids the condensate from stagnating in the chamber and pipes.

[0030] Enhanced anti-clogging capability in low-temperature environments: The volume of a single pressure sensing space 31 is designed to be larger than that of the connected air intake pipe 5. By utilizing air pressure changes, a pressure difference is formed between the pressure sensing space 31 and the air intake pipe 5, thereby generating a driving effect to accelerate the discharge of condensate. Even in low-temperature environments where condensate has a strong tendency to freeze, this structure can reduce the risk of freezing and clogging through the combined action of the drainage slope 52 and the pressure difference, ensuring the continuous and reliable operation of the sensor.

[0031] Strong adaptability and installation compatibility: This technical solution upgrades the drainage function by optimizing the internal cavity structure without changing the overall size of the sensor. This ensures compatibility with existing vehicle installation conditions and avoids the volume expansion problem caused by structural additions, making it highly scalable.

[0032] Improved system reliability and durability: The stacked layout of the drainage chamber 3 and the equipment chamber 2 effectively isolates the sensor elements from condensate. With the equipment chamber 2 on top and the drainage chamber 3 on the bottom, gravity prevents condensate from entering the equipment chamber 2 located above it. This avoids condensate from directly contacting or intruding into the sensitive area of ​​the differential pressure sensing element 4, fundamentally improving the reliability and service life of the sensor under extreme operating conditions.

[0033] In summary, this technical solution not only solves the problems of low drainage efficiency, easy freezing and blockage of condensate at low temperatures, and limited installation space of existing differential pressure sensors, but also achieves an efficient and adaptive drainage design, which significantly improves the safety, stability and market applicability of the product while ensuring accurate measurement.

[0034] As one alternative implementation method: Regarding the operation of the dual drainage system of the automatic drainage structure inside the differential pressure sensor, this implementation is, for example... Figure 1 and Figure 2As shown, when the air pressure in the pressure sensing space 31 changes, the amount of gas expansion or contraction in the pressure sensing space 31 exceeds the volume of the air intake pipe 5, pushing the water film formed by condensate in the air intake pipe 5 and the condensate entering the air intake pipe 5 from the pressure sensing space 31 to be discharged; in the pressure sensing space 31 of the drainage chamber 3, the condensate forms a path for drainage from the pressure sensing space 31 to the air intake pipe 5 by gravity self-drainage, and the water film formed by condensate in the air intake pipe 5 is broken by pressure difference self-drainage, promoting the efficient discharge of condensate from the pressure sensing space 31 and the air intake pipe 5 from the outer shell 1.

[0035] In application, a dual drainage system is formed by two drainage methods: gravity self-drainage and differential pressure self-drainage. The differential pressure self-drainage relies on the volume difference between the pressure sensing space 31 and the intake pipe 5. When the exhaust gas conditions cause pressure fluctuations in the pressure sensing space 31, the volume change caused by the expansion or contraction of the gas exceeds the volume of the intake pipe 5, which can push the condensate film in the intake pipe 5 and the condensate that has entered it out. At the same time, the condensate in the drainage chamber 3 can flow to the intake pipe 5 along the drainage slope 52 by gravity self-drainage, and then the differential pressure self-drainage breaks the water film in the intake pipe 5. The two drainage methods work together to achieve efficient discharge of condensate in the sensor.

[0036] This technology effectively avoids the problem of condensate water lingering or clogging at the air intake pipe 5 by combining the effects of gravity and differential pressure, ensuring that the differential pressure sensor 9 can maintain the accuracy and stability of signal output even in extreme environments.

[0037] In addition, the dual drainage system can be further linked with the temperature detection unit on the differential pressure sensing element 4 inside the differential pressure sensor 9. When a low temperature environment is detected and the freezing trend of condensate is predicted, the exhaust flow is adjusted by the engine ECU to accelerate the discharge of condensate in conjunction with the dual drainage system, thereby further enhancing the drainage guarantee capability under extreme weather conditions.

[0038] Regarding the enhanced drainage effect of the aforementioned gravity-fed drainage, this implementation is as follows: Figure 2 As shown, the inner wall of the pressure sensing space 31 and the position where the drain chamber 3 connects to the air inlet pipe 5 are uniformly provided with transition rounded corners or transition chamfers to improve the smoothness of condensate sliding down the inner wall of the drain chamber 3 to the air inlet pipe 5 and being discharged to the outside of the outer casing 1.

[0039] When applied, the inner wall of the pressure sensing space 31 and the connection between the drainage chamber 3 and the air inlet pipe 5 are uniformly arranged with transition rounded corners or chamfers, so that when the condensate flows along the inner wall, it can smoothly transition to the inlet of the air inlet pipe 5, reducing the phenomenon of water droplets lingering at the corners, thereby improving the smoothness of condensate sliding and discharge; ensuring the fluidity of condensate in the drainage chamber 3 and air inlet pipe 5 inside the sensor, significantly enhancing the gravity self-drainage effect, solving the problem that traditional right-angled inner walls are prone to forming water accumulation points, and improving the stability and reliability of drainage.

[0040] In some application scenarios, the curvature radius of the transition fillet can be optimized by partitioning to make the drainage path more in line with the flow trend of condensate; it is even possible to add local microchannel structures at key turning points to further improve the condensate diversion efficiency.

[0041] Furthermore, a hydrophobic layer is sprayed onto the inner wall of the pressure sensing space 31.

[0042] The hydrophobic layer is a Teflon coating, a polyboron siloxane coating, a fluorosiloxane-modified nano-silica composite coating, or a carbon fiber silicone resin composite coating.

[0043] When applied, the hydrophobic layer prevents condensate from adhering to a large area on the inner wall surface. Instead, it quickly collects in the form of water droplets and slides down the drainage slope 52, thereby accelerating the drainage speed and preventing water droplet retention. This improves the efficiency and thoroughness of condensate self-drainage and solves the retention problem caused by condensate adhesion in the traditional differential pressure sensor 9 structure.

[0044] Depending on the application scenario, a double-layer or gradient hydrophobic coating structure is further adopted. The outer layer is a nano-silica hydrophobic composite layer, and the inner layer is a high-temperature resistant Teflon coating. The outer layer-inner layer-inner wall are stacked in the drainage chamber 3 to achieve both high hydrophobicity and high temperature resistance. This avoids excessive reduction of the hydrophobic angle of the hydrophobic layer due to high temperature, and meets the stringent exhaust gas environment requirements of diesel vehicles or high-performance engines.

[0045] Regarding measures to prevent the formation of a closed water film within the air intake pipe 5 during condensation, this implementation is as follows: Figure 2 As shown, the inner wall of the intake pipe 5 is roughened to increase the roughness of the inner wall of the intake pipe 5 and reduce the formation of a water film that closes the inner cross section of the intake pipe by condensate on the inner wall of the intake pipe.

[0046] During application, the inner wall of the intake pipe 5 is roughened to increase its surface roughness, thus breaking the condition for condensate to form a continuous water film inside the pipe. During the process, the condensate is divided into discrete small water droplets on the rough surface of the inner wall of the intake pipe 5, thereby avoiding the situation where the water film closes the pipe cross section and hinders the gas flow. This effectively reduces the probability of gas path blockage caused by condensate, ensuring that the differential pressure sensor 9 still has stable ventilation capacity and pressure response speed under complex working conditions.

[0047] In addition, roughening treatment can be combined with plasma etching, sandblasting or laser microtexturing processes. This not only allows for flexible selection based on different material properties, but also forms directional microtextures on the surface of the air intake pipe 5, enabling condensate to be discharged faster in a specific direction under the combined action of gravity and airflow.

[0048] This implementation example Figures 1 to 3 As shown, the differential pressure sensor 9 also includes a cover plate 6 for the maintenance window 21 located above the equipment compartment 2. A waterproof sealant 71 is provided around the lower end face of the cover plate 6 to form a seal between the cover plate 6 and the peripheral groove of the maintenance window 21. The cover plate 6 is provided with a pressure relief hole 61, and a pressure relief head 62 is installed in the pressure relief hole 61. The pressure relief head 62 is a sealant plunger, which is used to push the pressure relief head 62 upward when the internal pressure is high, so that the gap between the peripheral wall of the pressure relief head 62 and the inner peripheral wall of the pressure relief hole 61 is exposed, forming an exhaust gap.

[0049] It also includes a support frame 7, which is installed inside the equipment compartment 2. The differential pressure sensing element 4 is installed on the support frame 7. Waterproof sealant 71 is also provided on the end face of the support frame 7 facing the drainage compartment 3 to form a seal with the surrounding groove of the drainage compartment 3.

[0050] One end of the housing 1 is provided with an electrical connection port 8, and multiple data transmission terminals 81 are provided inside the electrical connection port 8. The differential pressure sensing element 4 forms an electrical connection through the data transmission terminals 81 to connect with external components and transmit differential pressure sensing data. The other end of the housing 1 is also provided with a mounting ear hole 11 for connecting with bolts at the mounting position to fix the differential pressure sensor 9.

[0051] When applied, the differential pressure sensor 9 is provided with an inspection window 21 above the equipment compartment 2 and covered by a cover plate 6. The waterproof sealant 71 around the lower end face of the cover plate 6 forms a reliable seal with the periphery of the inspection window 21. Waterproof sealant 71 is also provided on the end face of the support frame 7 facing the drainage compartment 3 and in the slot between the differential pressure sensing element 4 and the support frame 7. This effectively prevents external moisture or dust or gas entering the drainage compartment 3 from the air inlet pipe 5 from entering the equipment compartment 2.

[0052] Under normal sensor operation, cover plate 6 ensures the sealing and stability of the internal cavity of housing 1. When the air pressure inside equipment compartment 2 rises abnormally due to exhaust gas fluctuations or environmental influences, the sealing plunger (pressure relief head 62) installed in the pressure relief hole 61 of cover plate 6 will be pushed out under air pressure. The gap between the peripheral wall of pressure relief head 62 and the inner peripheral wall of pressure relief hole 61 is exposed, forming an exhaust channel to quickly release the excessive internal air pressure. This ensures that the sensor can maintain the integrity of the housing and internal components when subjected to pressure shocks, effectively solving the problem that traditional sealing structures are prone to failure or damage under abnormal pressure, and improving the safety and durability of the sensor.

[0053] 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.

Claims

1. An automatic drainage structure for the internal pipeline of a differential pressure sensor, characterized in that, Includes a housing for accommodating the differential pressure sensing element to be matched; The outer casing contains a sequentially stacked and interconnected equipment compartment and a drainage compartment. The differential pressure sensing element is installed inside the equipment compartment, with the pressure sensing end of the differential pressure sensing element facing the drainage compartment. The drainage chamber is divided into multiple pressure sensing spaces, and the multiple pressure sensing ends of the differential pressure sensing element correspond to the multiple pressure sensing spaces respectively, and sense the air pressure of each pressure sensing space. Multiple air inlet pipes are provided on one side of the drainage chamber, and the multiple air inlet pipes are respectively connected to the multiple pressure sensing spaces; The drainage chamber is provided with a drainage slope that slopes from the drainage chamber toward the air intake pipe on one side of the drainage chamber. This slope is used to promote the discharge of condensate water condensed on the inner wall of the pressure sensing space through the air intake pipe to the outside of the outer shell by gravity drainage. The volume of a single pressure sensing space is greater than the volume of the connected air intake pipe, and is used to generate pressure differential self-drainage by utilizing the air pressure change of the pressure sensing space.

2. The automatic drainage structure for the internal pipeline of the differential pressure sensor according to claim 1, characterized in that, When the air pressure in the pressure sensing space changes, the amount of gas expansion or contraction in the pressure sensing space exceeds the volume of the air intake pipe, pushing the water film formed by condensate in the air intake pipe and the condensate that entered the air intake pipe from the pressure sensing space to be discharged. Within the pressure sensing space of the drainage chamber, condensate is drained by gravity, creating a path for drainage from the pressure sensing space to the air intake pipe. The water film formed by condensate in the air intake pipe is broken by pressure differential drainage, promoting the efficient discharge of condensate from the pressure sensing space and the air intake pipe from the outer casing.

3. The automatic drainage structure for the internal pipeline of the differential pressure sensor according to claim 1, characterized in that, The inner wall of the pressure sensing space and the location where the drainage chamber connects to the air inlet pipe are uniformly provided with transition rounded corners or transition chamfers to improve the smoothness of condensate sliding down the inner wall of the drainage chamber to the air inlet pipe and being discharged to the outside of the outer casing.

4. The automatic drainage structure for the internal pipeline of the differential pressure sensor according to claim 1, characterized in that, The inner wall of the pressure sensing space is coated with a hydrophobic layer.

5. The automatic drainage structure for the internal pipeline of the differential pressure sensor according to claim 4, characterized in that, The hydrophobic layer is a Teflon coating, a polyboron siloxane coating, a fluorosiloxane-modified nano-silica composite coating, or a carbon fiber silicone resin composite coating.

6. The automatic drainage structure for the internal pipeline of the differential pressure sensor according to any one of claims 1 or 4, characterized in that, The inner wall of the intake pipe is roughened to increase its roughness and reduce the formation of a water film that seals the inner cross-section of the intake pipe by condensate.

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