Non-oil-filled differential pressure sensor and packaging method thereof

Abstract

The invention relates to an oil-filling-free differential pressure sensor and a packaging method thereof, and relates to the technical field of differential pressure sensors, the oil-filling-free differential pressure sensor comprises a base arranged on a pressure medium pipeline and a differential pressure sensing chip arranged on the base, medium grooves are formed in the two ends of the base, and the medium grooves are communicated with the differential pressure sensing chip. The pressure difference sensing chip is connected with the base through an installation structure so that the two medium grooves can be arranged in a separated mode, pressure media on the two sides of the base can directly act on the two sides of the pressure difference sensing chip through the corresponding medium grooves, and a sealing structure connected with a pressure medium pipeline in a sealed mode is arranged on the base. The base is provided with a steel mesh diaphragm covering an opening of the medium groove, and the steel mesh diaphragm is connected with the base through a connecting structure. According to the invention, silicone oil does not need to be added into the sensor, so that the risks of oil leakage and measurement medium pollution do not exist.

Description

Technical Field

[0001] The present application relates to the technical field of differential pressure sensors, and in particular to an oil-free differential pressure sensor and a packaging method thereof. Background Art

[0002] The differential pressure sensor is a sensor used to measure the difference between two pressures. It is usually used to measure the pressure difference between the front and rear ends of a device or component. It is widely used in textile workshops, boiler air supply, underground ventilation, electricity, coal, spinning cotton boxes, dust removal equipment, and industry pressure process control fields.

[0003] When measuring clean, non-corrosive gases or liquids, existing differential pressure sensor solutions use an oil-filled core and a corrugated diaphragm. Silicone oil is injected into the sensor through an oil-filled pipe so that each pressure-conducting hole in the sensor body is filled with silicone oil for conducting pressure. However, during use, the sensor is large in size and there is a risk of oil leakage and contamination of the measuring medium. Summary of the invention

[0004] In order to improve the risk of oil leakage and contamination of the measuring medium in the differential pressure sensor during use, the present application provides an oil-free differential pressure sensor and a packaging method thereof.

[0005] On the one hand, the present application provides an oil-free differential pressure sensor adopts the following technical solution: An oil-free differential pressure sensor comprises a base arranged on a pressure medium pipeline and a pressure differential sensing chip arranged on the base, both ends of the base are provided with medium grooves, the pressure differential sensing chip is connected to the base through a mounting structure so as to be able to separate the two medium grooves, the pressure medium on both sides of the base can directly act on both sides of the pressure differential sensing chip through the corresponding medium grooves, and the base is provided with a sealing structure sealed and connected to the pressure medium pipeline; A steel mesh diaphragm covering the opening of the medium slot is arranged on the base, and the steel mesh diaphragm is connected to the base via a connecting structure.

[0006] By adopting the above technical solution, the sensor is installed at the pressure measuring position on the pressure medium pipeline, the sealing structure and the pipeline are sealed, and then the pressure medium on both sides of the sensor enters the two medium grooves. The pressure medium directly acts on the pressure difference sensing chip, and the pressure difference value of the pressure medium on both sides of the sensor is monitored by the pressure difference sensing chip. This solution does not require the addition of silicone oil to the sensor, so there is no risk of oil leakage or contamination of the measuring medium; through the setting of the steel mesh diaphragm, external contaminants can be isolated from entering the sensor to ensure the cleanliness of the inside of the sensor.

[0007] In a specific possible implementation scheme, the two dielectric slots are connected via a connecting hole, and the pressure difference sensing chip is disposed in one of the dielectric slots and is capable of blocking the connecting hole; The mounting structure comprises a ceramic sheet and a chip adhesive layer. The ceramic sheet is fixedly arranged on the pressure difference sensing chip. The ceramic sheet and the base are bonded by the chip adhesive layer.

[0008] By adopting the above technical solution, the pressure difference sensing chip is connected to the chip adhesive layer through the ceramic sheet, which can keep the pressure difference sensing chip clean. The chip adhesive layer is bonded to facilitate the installation of the pressure difference sensing chip and improve the sealing of the isolation of the two dielectric grooves.

[0009] In a specific possible implementation scheme, the base is provided with a chip protection cover in the dielectric tank, the chip protection cover can wrap the pressure difference sensing chip, and the chip protection cover is located between the steel mesh diaphragm and the bottom wall of the dielectric tank, so that the steel mesh diaphragm can press and fix the chip protection cover on the bottom wall of the dielectric tank; A ceramic pad is embedded in the dielectric groove, the chip protection cover is penetrated on the ceramic pad, and an outer edge is provided on the chip protection cover, and the outer edge can overlap on the ceramic pad.

[0010] By adopting the above technical solution and using the chip protection cover, dust can be prevented and the pressure difference sensing chip can be protected; and the provision of a ceramic pad can improve the firmness of the installation of the chip protection cover.

[0011] In a specific possible implementation scheme, the sealing structure includes a sealing ring groove and a sealing ring, the sealing ring groove is opened on the peripheral side wall of the base, the sealing ring is embedded in the sealing ring groove and can abut against the pressure medium pipeline to form a seal.

[0012] By adopting the above technical solution, the sealing ring is arranged in the sealing ring groove, which can improve the stability of the installation of the sealing ring and the base, and improve the sealing effect of the sensor installation through the abutment sealing between the sealing ring and the pressure medium pipeline.

[0013] In a specific possible implementation manner, the connection structure includes a pressure ring, and the pressure ring is fixedly connected to the base so as to be able to press and fix the steel mesh diaphragm on the base.

[0014] By adopting the above technical solution, the steel mesh diaphragm is pressed and fixed on the base by using a pressure ring, thereby improving the stability of the installation of the steel mesh diaphragm.

[0015] In a specific possible implementation manner, the pressure ring is welded to the base.

[0016] In a specific possible implementation scheme, an internal threaded sleeve is fixedly provided on the base, and the pressure ring is threadedly connected in the internal threaded sleeve so as to be able to press and fix the steel mesh diaphragm.

[0017] By adopting the above technical solution and providing an internal threaded sleeve, it is easy to disassemble and assemble the steel mesh diaphragm, facilitate subsequent maintenance and replacement, and extend the service life of the product.

[0018] In a specific feasible implementation scheme, an exhaust cavity is opened in the base, and a guide component is provided on the base, and the guide component can guide the compressed gas at the pressure difference sensing chip into the exhaust cavity, and the exhaust cavity is connected to the corresponding medium groove through a reflux channel so that the pressure medium in the exhaust cavity can flow back into the medium groove, and a control component for controlling the connection or closing of the reflux channel is provided on the base.

[0019] By adopting the above technical solution, when the pressure medium enters the connecting hole from the medium groove on one side, it will squeeze the air in the connecting hole to the pressure difference sensing chip. The compressed gas at the pressure difference sensing chip enters the exhaust chamber under the guidance of the guide component, so that the pressure medium contacts the pressure difference sensing chip, thereby improving the pressure transmission efficiency between the pressure medium and the pressure difference sensing chip and reducing the pressure measurement error; as the compressed air enters the exhaust chamber, part of the pressure medium also enters the exhaust chamber. When the differential pressure sensor is disassembled, the reflux channel is opened through the control component, so that the pressure medium in the exhaust chamber flows back to the medium groove and is discharged from the sensor, thereby ensuring the cleanliness of the inside of the sensor and improving the convenience of reusing the sensor.

[0020] In a specific possible implementation scheme, the guide assembly includes a guide cylinder and a guide tube, the guide tube is coaxially fixed in the guide cylinder, and a guide channel is formed between the guide cylinders, the guide cylinder is inserted into the connecting hole, and a guide hole connected to the exhaust chamber and the guide channel is opened on the guide cylinder, and the end of the guide tube extends to the pressure difference sensing chip so that the compressed air at the pressure difference sensing chip can flow into the guide hole along the guide channel.

[0021] By adopting the above technical solution, when the pressure medium enters the connecting hole, the pressure medium first flows from the guide pipe to the pressure difference sensing chip, compresses the compressed gas at the pressure difference sensing chip into the guide channel, and enters the guide hole along the guide channel, and is discharged into the exhaust chamber, thereby realizing the guidance of the compressed gas.

[0022] On the other hand, the packaging method of a non-oil-filled differential pressure sensor provided in the present application adopts the following technical solution: A packaging method for an oil-free differential pressure sensor, using the above-mentioned oil-free differential pressure sensor, further comprising the following steps: S1, base manufacturing, the base is processed by a sintering process, and then corresponding grooves and holes are opened on the base; S2, installing the pressure difference sensing chip in the dielectric slot through the mounting structure, so that the two dielectric slots are isolated from each other; S3. Install the steel mesh diaphragm at the opening of the medium tank through the connecting structure, and cover the opening of the medium tank.

[0023] In summary, the present application includes at least one of the following beneficial technical effects: 1. Install the sensor at the pressure measuring position on the pressure medium pipeline, seal the sealing structure and the pipeline, and then the pressure medium on both sides of the sensor enters the two medium grooves. The pressure medium directly acts on the pressure difference sensing chip, and the pressure difference value of the pressure medium on both sides of the sensor is monitored by the pressure difference sensing chip. This solution does not require the addition of silicone oil to the sensor, so there is no risk of oil leakage or contamination of the measuring medium; the setting of the steel mesh diaphragm can isolate external pollutants from entering the sensor to ensure the cleanliness of the inside of the sensor; 2. Using the chip protection cover can prevent dust and protect the pressure difference sensing chip; setting a ceramic pad can improve the firmness of the chip protection cover installation; 3. By setting the internal thread sleeve, it is easy to disassemble and assemble the steel mesh diaphragm, facilitate the later maintenance and replacement, and extend the service life of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of an oil-free differential pressure sensor according to Example 1 of the present application.

[0025] Figure 2 yes Figure 1 Enlarged view of part A in the middle.

[0026] Figure 3 It is a schematic diagram for showing the structure of the chip protection cover.

[0027] Figure 4 It is a structural schematic diagram of an oil-free differential pressure sensor according to Example 2 of the present application.

[0028] Figure 5 It is a structural schematic diagram of an oil-free differential pressure sensor according to Example 3 of the present application.

[0029] Figure 6 yes Figure 5 Enlarged view of part B in the middle.

[0030] Figure 7 yes Figure 5 Enlarged view of part C in the middle.

[0031] Explanation of the reference numerals in the accompanying drawings: 1. base; 11. medium groove; 12. connecting hole; 2. differential pressure sensing chip; 3. mounting structure; 31. ceramic sheet; 32. chip adhesive layer; 33. chip protection cover; 34. ceramic pad; 35. outer edge; 4. sealing structure; 41. sealing ring groove; 42. sealing ring; 5. steel mesh diaphragm; 6. connecting structure; 61. pressure ring; 62. internal threaded sleeve; 71. exhaust chamber; 72. exhaust channel; 73. guide assembly; 731. guide cylinder; 732. guide tube; 733. edge; 734. guide channel; 735. guide hole; 736. reflux channel; 74. control component; 741. valve core; 742. control spring; 743. adjusting bolt; 744. valve chamber. DETAILED DESCRIPTION

[0032] The following is combined with Figure 1-7 This application is described in further detail.

[0033] The embodiment of the present application discloses an oil-free differential pressure sensor.

[0034] Example 1 Reference Figure 1 A non-oil-filled differential pressure sensor includes a base 1 and a differential pressure sensing chip 2. The differential pressure sensor of this embodiment is used in a clean, non-corrosive gas or liquid environment. The base 1 in this embodiment is a sintered base 1 made by a sintering process. The differential pressure sensing chip 2 is made of silicon material, and a metal coating is provided on the surface to improve its wear resistance and conductivity. Both ends of the base 1 are provided with a dielectric groove 11. The apertures and depths of the two dielectric grooves 11 are different. The differential pressure sensing chip 2 is set in a dielectric groove 11 with a shallow depth and a large aperture. The two dielectric grooves 11 are connected by a connecting hole 12. The differential pressure sensing chip 2 is connected to the base 1 through a mounting structure 3, and the connecting hole 12 can be isolated, so that the pressure medium on both sides of the base 1 can directly act on both sides of the differential pressure sensing chip through the corresponding dielectric groove 11. In addition, a sealing structure 4 that is sealed and connected to the pressure medium pipeline is provided on the base 1.

[0035] Reference Figure 1 , a steel mesh diaphragm 5 is provided at the opening of each medium slot 11, and the steel mesh diaphragm 5 is connected to the base 1 through a connecting structure 6. The diameter of the steel mesh diaphragm 5 is larger than the diameter of the corresponding medium slot 11 to ensure that the steel mesh diaphragm 5 blocks the opening of the medium slot 11. The steel mesh diaphragm 5 is made of stainless steel, and the mesh number can be selected according to actual needs, such as 100 mesh to 300 mesh. Through different mesh numbers, it can better adapt to the use requirements in different environments. For example, for application scenarios with higher requirements, a 300-mesh steel mesh diaphragm 5 can be selected to further improve the anti-fouling performance. The steel mesh diaphragm 5 is connected to the base 1 through a connecting structure 6. The setting of the steel mesh diaphragm 5 is mainly used to isolate external pollutants and maintain the cleanliness of the internal structure.

[0036] When installing the differential pressure sensor, the differential pressure sensing chip 2 is installed in the medium groove 11 through the installation structure 3 so that the two medium grooves 11 are isolated from each other, and the steel mesh diaphragm 5 is installed at the opening of the medium groove 11 through the connecting structure 6 to cover the opening of the medium groove 11. The sensor is installed on the pressure medium pipeline and sealed to the pressure medium pipeline through the sealing structure 4. The installation of the differential pressure sensor has been completed.

[0037] The pressure medium on both sides of the sensor enters the two medium grooves 11, and the pressure medium directly acts on the pressure difference sensing chip 2. The pressure difference value of the pressure medium on both sides of the sensor is monitored by the pressure difference sensing chip 2. This solution does not require the addition of silicone oil to the sensor, so there is no risk of oil leakage or contamination of the measuring medium.

[0038] Reference Figure 1 , Figure 2 The mounting structure 3 in this embodiment includes a ceramic sheet 31 and a chip adhesive layer 32. The ceramic sheet 31 is an annular structure. The ceramic sheet 31 is fixedly arranged on the side of the pressure difference sensing chip 2 close to the connecting hole 12. The ceramic sheet 31 and the base 1 are bonded by the chip adhesive layer 32. The chip adhesive layer 32 can be made of epoxy resin glue or other high-strength adhesives, such as cyanoacrylate. The ceramic sheet 31 is made of high-purity alumina ceramics, which has good insulation performance and heat resistance and is suitable for a variety of working environments.

[0039] Reference Figure 1 , Figure 2 and Figure 3 The base 1 is provided with a chip protection cover 33 and a ceramic pad 34 in the dielectric groove 11. The outer diameter of the ceramic pad 34 is the same as the aperture of the dielectric groove 11. The chip protection cover 33 is penetrated on the ceramic pad 34. The chip protection cover 33 is provided with an outer edge 35. The outer edge 35 can overlap the ceramic pad 34. The chip protection cover 33 is a cylindrical structure and wraps the pressure difference sensing chip 2. The chip protection cover 33 is located between the steel mesh diaphragm 5 and the bottom wall of the dielectric groove 11. The steel mesh diaphragm 5 presses and fixes the chip protection cover 33 on the bottom wall of the dielectric groove 11, and at the same time presses the outer edge 35 against the ceramic pad 34, thereby completing the fixing of the chip protection cover 33. The chip protection cover 33 can prevent dust and protect the pressure difference sensing chip 2; the ceramic pad 34 can improve the firmness of the installation of the chip protection cover 33.

[0040] Reference Figure 1 The connection structure 6 in this embodiment includes a pressure ring 61, and the pressure ring 61 corresponds to the steel mesh diaphragm 5 one by one. In this embodiment, the pressure ring 61 is welded to the steel mesh diaphragm 5. This method is more stable and can better press and fix the steel mesh diaphragm 5 on the base 1.

[0041] The number of the sealing structures 4 in this embodiment can be set as needed. The sealing structure 4 in this embodiment includes a sealing ring groove 41 and a sealing ring 42. The sealing ring groove 41 is provided on the peripheral side wall of the base 1. The sealing ring 42 is located and embedded in the sealing ring groove 41, and can abut against the pressure medium pipeline to form a seal. The sealing ring 42 can be made of fluororubber material, which has good heat resistance, chemical stability and mechanical strength, and is suitable for high-pressure and high-temperature application scenarios. The size design of the sealing ring groove 41 needs to ensure a close fit with the sealing ring 42 to ensure a good sealing effect.

[0042] The implementation principle of the embodiment of the present application is: the pressure medium on both sides of the sensor enters the two medium grooves 11, and the pressure medium directly acts on the pressure difference sensing chip 2. The pressure difference value of the pressure medium on both sides of the sensor is monitored by the pressure difference sensing chip 2. This solution does not require the addition of silicone oil to the sensor, so there is no risk of oil leakage or contamination of the measuring medium.

[0043] Example 2 Reference Figure 4 The difference between this embodiment and embodiment 1 is that an internal threaded sleeve 62 is fixedly provided on the base 1, the internal threaded sleeve 62 is integrally formed with the base 1, the axis of the internal threaded sleeve 62 is colinear with the axis of the steel mesh diaphragm 5, the pressure ring 61 is arranged in the internal threaded sleeve 62 and is threadedly connected to the internal threaded sleeve 62, and the steel mesh diaphragm 5 is pressed against the base 1 by screwing the pressure ring 61, which facilitates the disassembly and assembly of the steel mesh diaphragm 5, facilitates later maintenance and replacement, and extends the service life of the product.

[0044] Example 3 Reference Figure 5 , Figure 6 The difference between this embodiment and the second embodiment is that an exhaust cavity 71 is provided in the base 1, and the exhaust cavity 71 is connected to the connecting hole 12 through an exhaust channel 72. When the sensor is in a vertical state, the top height of the exhaust cavity 71 is greater than the height of the pressure difference sensing chip 2, so as to ensure that the compressed gas at the pressure difference sensing chip 2 can stably enter the exhaust cavity 71. A guide assembly 73 is provided on the base 1, and the guide assembly 73 can guide the compressed gas at the pressure difference sensing chip 2 to the exhaust cavity 71. The guide assembly 73 in this embodiment includes a guide cylinder 731 and a guide tube 732. The guide cylinder 731 is a cylinder inserted into the connecting hole 12. The outer diameter of the guide cylinder 731 is the same as the inner diameter of the connecting hole 12, so that when the guide cylinder 731 is inserted into the connecting hole 12, the guide cylinder 731 and the connecting hole 12 are slidably sealed. The guide cylinder 731 is opened at one end facing the pressure difference sensing chip 2, and the other end is closed. The outer peripheral side wall of the guide tube 731 is convex to form an edge 733. When the guide tube 731 is inserted into the connecting hole 12, the edge 733 overlaps the bottom wall of the dielectric groove 11 and is bonded and fixed to the bottom wall of the dielectric groove 11 through the chip adhesive layer 32.

[0045] Reference Figure 5 , Figure 6 The guide tube 732 is coaxially fixedly arranged in the guide tube 731. The end of the guide tube 732 away from the pressure difference sensing chip 2 passes through the end of the guide tube 731 away from the pressure difference sensing chip 2 to ensure that the pressure medium can flow to the pressure difference sensing chip 2 along the guide tube 732. A guide channel 734 is formed between the guide tube 732 and the guide tube 731. The pressure medium squeezes the compressed gas into the guide channel 734. The guide tube 731 is provided with a guide hole 735 connected with the exhaust channel 72 and the guide channel 734. The compressed gas and the pressure medium entering the guide channel 734 enter the exhaust channel 72 along the guide hole 735 and enter the exhaust chamber 71.

[0046] Reference Figure 5 , Figure 7 The exhaust channel 72 is connected to the corresponding medium groove 11 through the reflux channel 736, so that the pressure medium in the exhaust chamber 71 can flow back into the medium groove 11. The base 1 is provided with a control member 74 for controlling the connection or closing of the reflux channel 736. The control member 74 in this embodiment includes a valve core 741, a control spring 742, and an adjusting bolt 743. A valve chamber 744 arranged in series with the reflux channel 736 is opened in the base 1. The valve core 741 is slidingly sealed in the valve chamber 744. The control spring 742 is arranged on one side of the valve core 741. The adjusting bolt 743 is threadedly inserted on the base 1. The end of the adjusting bolt 743 extends into the valve chamber 744. The adjusting bolt 743 pushes the valve core 741 to move. At this time, the control spring 742 is compressed, and the reflux channel 736 is closed. The adjusting bolt 743 is rotated in the reverse direction, and the control spring 742 pushes the valve core 741 to slide, and the reflux channel 736 is opened.

[0047] The implementation principle of the embodiment of the present application is as follows: when the pressure medium enters the connecting hole 12 from the medium groove 11 on one side, it will squeeze the air in the connecting hole 12 to the pressure differential sensing chip 2. The pressure medium first flows from the guide tube 732 to the pressure differential sensing chip 2, and the compressed gas at the pressure differential sensing chip 2 is pressed into the guide channel 734, and enters the guide hole 735 along the guide channel 734, and is discharged into the exhaust chamber 71, so that the pressure medium contacts the pressure differential sensing chip 2. At this time, the adjusting bolt 743 pushes the valve block to block the return channel 736, so as to improve the pressure transmission efficiency between the pressure medium and the pressure differential sensing chip 2 and reduce the pressure measurement error; as the compressed air enters the exhaust chamber 71, part of the pressure medium also enters the exhaust chamber 71. When the differential pressure sensor is disassembled, the adjusting bolt 743 is turned to control the spring 742 to push the valve block to slide, open the return channel 736, so that the pressure medium in the exhaust chamber 71 flows back to the medium groove 11 and is discharged from the sensor, thereby ensuring the cleanliness of the inside of the sensor and improving the convenience of reusing the sensor.

[0048] The embodiment of the present application discloses a packaging method for an oil-free differential pressure sensor.

[0049] A packaging method for an oil-free differential pressure sensor, using the above-mentioned oil-free differential pressure sensor, further comprising the following steps: S1, manufacturing the base 1, processing the base 1 by a sintering process, and then opening corresponding grooves, holes and cavities on the base 1.

[0050] S2. Install the ceramic sheet 31 on the pressure difference sensing chip 2, and then bond the ceramic sheet 31 to the dielectric groove 11 and the connecting hole 12 through the chip adhesive layer 32, so that the pressure difference sensing chip 2 blocks the connecting hole 12, and then insert the chip protection cover 33 into the ceramic pad 34, and then insert the ceramic pad 34 into the dielectric groove 11, so that the chip protection cover 33 surrounds the pressure difference sensing chip 2.

[0051] S3. Screw the pressure ring 61 into the internal threaded sleeve 62. The pressure ring 61 presses and fixes the steel mesh diaphragm 5 on the base 1. At this time, the steel mesh diaphragm 5 presses and fixes the chip protection cover 33 in the medium slot 11, thereby completing the packaging of the differential pressure sensor.

[0052] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An oil-free differential pressure sensor, characterized in that: The invention comprises a base (1) arranged on a pressure medium pipeline and a pressure difference sensing chip (2) arranged on the base (1); both ends of the base (1) are provided with medium grooves (11); the pressure difference sensing chip (2) is connected to the base (1) via a mounting structure (3) so as to be able to separate and arrange the two medium grooves (11); the pressure medium on both sides of the base (1) can directly act on both sides of the pressure difference sensing chip (2) through the corresponding medium grooves (11); and the base (1) is provided with a sealing structure (4) which is sealed and connected to the pressure medium pipeline; The base (1) is provided with a steel mesh diaphragm (5) covering the opening of the medium slot (11), and the steel mesh diaphragm (5) is connected to the base (1) via a connecting structure (6).

2. The oil-free differential pressure sensor according to claim 1, characterized in that: The two dielectric grooves (11) are connected via a connecting hole (12); the pressure difference sensing chip (2) is arranged in one of the dielectric grooves (11) and is capable of blocking the connecting hole (12); The mounting structure (3) comprises a ceramic sheet (31) and a chip adhesive layer (32); the ceramic sheet (31) is fixedly arranged on the pressure difference sensing chip (2); and the ceramic sheet (31) and the base (1) are bonded via the chip adhesive layer (32).

3. The oil-free differential pressure sensor according to claim 1, characterized in that: The base (1) is provided with a chip protection cover (33) in the dielectric groove (11), and the chip protection cover (33) can wrap the pressure difference sensing chip (2), and the chip protection cover (33) is located between the steel mesh diaphragm (5) and the bottom wall of the dielectric groove (11), so that the steel mesh diaphragm (5) can press and fix the chip protection cover (33) on the bottom wall of the dielectric groove (11); A ceramic pad (34) is embedded in the dielectric groove (11), the chip protection cover (33) is inserted into the ceramic pad (34), an outer edge (35) is provided on the chip protection cover (33), and the outer edge (35) can overlap the ceramic pad (34).

4. The oil-free differential pressure sensor according to claim 1, characterized in that: The sealing structure (4) comprises a sealing ring groove (41) and a sealing ring (42); the sealing ring groove (41) is provided on the peripheral side wall of the base (1); the sealing ring (42) is located and embedded in the sealing ring groove (41) and can abut against the pressure medium pipeline to form a seal.

5. The oil-free differential pressure sensor according to claim 1, characterized in that: The connection structure (6) comprises a pressure ring (61), and the pressure ring (61) is fixedly connected to the base (1) so as to be able to press and fix the steel mesh diaphragm (5) on the base (1).

6. The oil-free differential pressure sensor according to claim 5, characterized in that: The pressure ring (61) is welded to the base (1).

7. The oil-free differential pressure sensor according to claim 5, characterized in that: An internal thread sleeve (62) is fixedly provided on the base (1), and the pressure ring (61) is threadedly connected in the internal thread sleeve (62) so that the pressure ring (61) can be pressed and fixed.

8. The oil-free differential pressure sensor according to claim 1, characterized in that: An exhaust cavity (71) is provided in the base (1), and a guide component (73) is provided on the base (1). The guide component (73) can guide the compressed gas at the pressure difference sensing chip (2) into the exhaust cavity (71). The exhaust cavity (71) is connected to the corresponding medium groove (11) through a reflux channel (736) so that the pressure medium in the exhaust cavity (71) can flow back into the medium groove (11). The base (1) is provided with a control component (74) for controlling the connection or closing of the reflux channel (736).

9. The oil-free differential pressure sensor according to claim 8, characterized in that: The guide assembly (73) comprises a guide cylinder (731) and a guide tube (732). The guide tube (732) is coaxially fixedly arranged in the guide cylinder (731) and forms a guide channel (734) between the guide cylinders (731). The guide cylinder (731) is inserted into the connecting hole (12). The guide cylinder (731) is provided with a guide hole (735) connected with the exhaust chamber (71) and the guide channel (734). The end of the guide tube (732) extends to the pressure difference sensing chip (2) so that the compressed air at the pressure difference sensing chip (2) can flow into the guide hole (735) along the guide channel (734).

10. A packaging method for an oil-free differential pressure sensor, using the oil-free differential pressure sensor according to any one of claims 1 to 9, characterized in that: The following steps are also included: S1, manufacturing the base (1), processing the base (1) by a sintering process, and then opening corresponding grooves and holes on the base (1); S2, installing the pressure difference sensing chip (2) in the dielectric groove (11) through the mounting structure (3), so that the two dielectric grooves (11) are isolated from each other; S3. Install the steel mesh diaphragm (5) at the opening of the medium tank (11) through the connecting structure (6), and cover the opening of the medium tank (11).

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