Differential pressure sensor
By integrating the structure and designing the pressure-conducting fluid, the problem of matrix deformation caused by weak welding points is solved, which improves the measurement accuracy and overload resistance of the differential pressure sensor and reduces manufacturing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-11
- Publication Date
- 2026-03-17
AI Technical Summary
In existing differential pressure sensors, weak points are easily formed at the welded joints under medium and high pressure or harsh operating conditions, which leads to deformation of the substrate under stress, affecting measurement accuracy and increasing manufacturing costs.
The differential pressure sensor adopts an integrated structure, using positive and negative pressure isolation diaphragms and an overload protection diaphragm. Overload protection is achieved through the flow of pressure-conducting fluid, avoiding welding and improving structural strength and measurement accuracy.
This improves the measurement accuracy of differential pressure sensors, reduces manufacturing costs, enhances overload resistance, and simplifies the manufacturing process.
Smart Images
Figure CN121678024A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of detection equipment technology, and in particular to a differential pressure sensor. Background Technology
[0002] Differential pressure sensors, as important industrial sensors, are widely used in process control, fluid measurement, environmental monitoring, and other fields. Their core principle is to acquire a signal by measuring the pressure difference acting on both sides of a sensitive element. Traditional differential pressure sensors typically use a silicon mount structure to encapsulate the core differential pressure chip and transmit external pressure to the chip through a transmission medium such as silicone oil.
[0003] Existing differential pressure sensors, especially those used in medium- or high-pressure or harsh operating conditions, typically feature overload protection diaphragms to protect the differential pressure chip and prevent it from being damaged by excessive pressure. To facilitate the installation of the overload protection diaphragm, the substrate is usually designed as a two- or multi-piece structure, which is welded together into a single unit.
[0004] However, when differential pressure sensors are subjected to high pressure or assembly stress, weak points can easily form at the welded joints, causing stress concentration at these joints. This leads to deformation of the substrate, resulting in data deviation and reduced measurement accuracy. Welded connections also increase the manufacturing cost and process complexity of the substrate. Summary of the Invention
[0005] The purpose of this invention is to provide a differential pressure sensor. The differential pressure sensor has an integrated substrate structure that does not require welding, has a simple structure, low cost, and avoids substrate deformation under stress, thereby improving measurement accuracy. The positive pressure overload protection diaphragm and the negative pressure overload protection diaphragm together generate sufficient deformation to achieve a better protection effect for the differential pressure chip.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] A differential pressure sensor is provided, comprising:
[0008] Matrix;
[0009] A positive pressure isolation diaphragm and a negative pressure isolation diaphragm, wherein the positive pressure isolation diaphragm and the negative pressure isolation diaphragm are respectively located on opposite sides of the substrate;
[0010] A positive pressure overload protection diaphragm and a negative pressure overload protection diaphragm are provided on the substrate;
[0011] A differential pressure silicon holder is connected to the substrate, and a differential pressure chip is connected to the differential pressure silicon holder. The differential pressure chip has a positive pressure detection surface and a negative pressure detection surface.
[0012] A positive pressure pipeline assembly and a negative pressure pipeline assembly are provided, each containing a pressure-conducting fluid. The pressure-conducting fluid in the positive pressure pipeline assembly flows between a positive pressure isolation diaphragm, a positive pressure overload protection diaphragm, a negative pressure overload protection diaphragm, and a positive pressure detection surface. The pressure-conducting fluid in the negative pressure pipeline assembly flows between a negative pressure isolation diaphragm, a positive pressure overload protection diaphragm, a negative pressure overload protection diaphragm, and a negative pressure detection surface.
[0013] Optionally, the positive pressure overload protection diaphragm and the negative pressure overload protection diaphragm are located on opposite sides of the substrate, the positive pressure overload protection diaphragm is located between the positive pressure isolation diaphragm and the substrate, and the negative pressure overload protection diaphragm is located between the negative pressure isolation diaphragm and the substrate.
[0014] Optionally, the positive pressure overload protection diaphragm and the negative pressure overload protection diaphragm are arranged symmetrically about the central axis of the substrate.
[0015] Optionally, the positive pressure pipeline assembly includes a first positive pressure pipe, a second positive pressure pipe, and a third positive pressure pipe. The pressure-conducting fluid in the first positive pressure pipe flows between the positive pressure isolation diaphragm and the positive pressure overload protection diaphragm. The pressure-conducting fluid in the second positive pressure pipe flows to the side of the negative pressure overload protection diaphragm opposite to the negative pressure isolation diaphragm. The pressure-conducting fluid in the third positive pressure pipe flows to the positive pressure detection surface. The first positive pressure pipe, the second positive pressure pipe, and the third positive pressure pipe are interconnected.
[0016] Optionally, the negative pressure pipeline assembly includes a first negative pressure pipe, a second negative pressure pipe, and a third negative pressure pipe. The pressure-conducting fluid in the first negative pressure pipe flows between the negative pressure isolation diaphragm and the negative pressure overload protection diaphragm. The pressure-conducting fluid in the second negative pressure pipe flows to the side of the positive pressure overload protection diaphragm opposite to the positive pressure isolation diaphragm. The pressure-conducting fluid in the third negative pressure pipe flows to the negative pressure detection surface. The first negative pressure pipe, the second negative pressure pipe, and the third negative pressure pipe are interconnected.
[0017] Optionally, the substrate is provided with a groove, the differential pressure silicon seat extends into the groove and fits against the inner wall of the groove, a receiving cavity is formed between the differential pressure silicon seat and the inner wall of the groove, and the differential pressure chip is located in the receiving cavity.
[0018] Optionally, the differential pressure sensor further includes a fixing member connected to the differential pressure silicon base, the differential pressure chip connected to the fixing member, and the fixing member isolating the positive pressure detection surface from the negative pressure detection surface.
[0019] Optionally, the differential pressure sensor further includes an isolation sleeve, which is fitted onto the differential pressure silicon base and connected to the substrate.
[0020] Optionally, the differential pressure sensor further includes a connector, which is sleeved on the isolation sleeve and has external threads.
[0021] Optionally, the connector is welded to the base and the isolation sleeve respectively.
[0022] The beneficial effects of this invention are:
[0023] This invention provides a differential pressure sensor, comprising a substrate, a positive pressure isolation diaphragm, a negative pressure isolation diaphragm, a positive pressure overload protection diaphragm, a negative pressure overload protection diaphragm, a differential pressure silicon holder, a differential pressure chip, a positive pressure pipeline assembly, and a negative pressure pipeline assembly. The positive and negative pressure isolation diaphragms are located on opposite sides of the substrate. Both the positive and negative pressure overload protection diaphragms are disposed on the substrate. The differential pressure silicon holder is connected to the substrate, and a differential pressure chip is connected to the silicon holder. The differential pressure chip has a positive pressure detection surface and a negative pressure detection surface. Both the positive and negative pressure pipeline assemblies contain pressure-conducting fluids. The pressure-conducting fluid in the positive pressure pipeline assembly flows between the positive pressure isolation diaphragm, the positive pressure overload protection diaphragm, the negative pressure overload protection diaphragm, and the positive pressure detection surface. The pressure-conducting fluid in the negative pressure pipeline assembly flows between the negative pressure isolation diaphragm, the positive pressure overload protection diaphragm, the negative pressure overload protection diaphragm, and the negative pressure detection surface. When the positive pressure isolating diaphragm is subjected to pressure, the pressure first acts on the positive pressure overload protection diaphragm, and then is transmitted to the negative pressure overload protection diaphragm and the positive pressure detection surface. The first and second overload protection diaphragms deform together to reduce the instantaneous pressure on the positive pressure detection surface. When the negative pressure isolating diaphragm is subjected to pressure, the pressure first acts on the negative pressure overload protection diaphragm, and then is transmitted to the positive pressure overload protection diaphragm and the negative pressure detection surface. The first and second overload protection diaphragms deform together to reduce the instantaneous pressure on the negative pressure detection surface. The differential pressure sensor of this invention has an integrated structure, eliminating the need for welding, giving the substrate high structural strength, avoiding weak points, preventing data deviation caused by stress deformation of the substrate, and improving the measurement accuracy of the differential pressure sensor. Furthermore, the integrated structure simplifies the manufacturing process of the substrate and reduces its manufacturing cost. By incorporating positive and negative overload protection diaphragms, the differential pressure chip is protected against overload, preventing excessive pressure from causing it to break down. Furthermore, both the positive and negative overload protection diaphragms deform together to reduce stress at the differential pressure chip. Together, they can generate sufficient deformation within a short time to achieve effective protection of the differential pressure chip, thus giving the differential pressure sensor better overload resistance. Attached Figure Description
[0024] Figure 1This is a schematic diagram of the differential pressure sensor provided in an embodiment of the present invention;
[0025] Figure 2 yes Figure 1 Cross-sectional view of AA in the middle;
[0026] Figure 3 yes Figure 1 Cross-sectional view of BB in the middle;
[0027] Figure 4 yes Figure 3 Enlarged view of point A in the middle;
[0028] Figure 5 yes Figure 3 Enlarged view of point B in the middle;
[0029] Figure 6 yes Figure 2 Enlarged view of point C in the middle;
[0030] Figure 7 yes Figure 2 Enlarged view at point D;
[0031] Figure 8 yes Figure 2 Enlarged view of point E in the middle.
[0032] In the picture:
[0033] 1. Substrate; 2. Positive pressure isolation diaphragm; 3. Negative pressure isolation diaphragm; 4. Positive pressure overload protection diaphragm; 5. Negative pressure overload protection diaphragm; 6. Differential pressure silicon base; 7. Differential pressure chip; 8. Positive pressure pipeline assembly; 81. First positive pressure pipe; 82. Second positive pressure pipe; 83. Third positive pressure pipe; 9. Negative pressure pipeline assembly; 91. First negative pressure pipe; 92. Second negative pressure pipe; 93. Third negative pressure pipe; 10. Fixing component; 11. Isolation sleeve; 12. Connecting component; 13. Positive pressure oil filling pipe; 14. Negative pressure oil filling pipe;
[0034] 100. Groove. Detailed Implementation
[0035] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.
[0036] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0037] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0039] like Figures 1 to 8As shown, this embodiment provides a differential pressure sensor, which includes a substrate 1, a positive pressure isolation diaphragm 2, a negative pressure isolation diaphragm 3, a positive pressure overload protection diaphragm 4, a negative pressure overload protection diaphragm 5, a differential pressure silicon holder 6, a differential pressure chip 7, a positive pressure pipeline assembly 8, and a negative pressure pipeline assembly 9. The positive pressure isolation diaphragm 2 and the negative pressure isolation diaphragm 3 are located on opposite sides of the substrate 1. The positive pressure overload protection diaphragm 4 and the negative pressure overload protection diaphragm 5 are both disposed on the substrate 1. The differential pressure silicon holder 6 is connected to the substrate 1, and the differential pressure chip 7 is connected to the differential pressure silicon holder 6. The differential pressure chip 7 has a positive pressure detection surface and a negative pressure detection surface. Both the positive pressure pipeline assembly 8 and the negative pressure pipeline assembly 9 contain pressure-conducting fluid. The pressure-conducting fluid in the positive pressure pipeline assembly 8 flows between the positive pressure isolation diaphragm 2, the positive pressure overload protection diaphragm 4, the negative pressure overload protection diaphragm 5, and the positive pressure detection surface. The pressure-conducting fluid in the negative pressure pipeline assembly 9 flows between the negative pressure isolation diaphragm 3, the positive pressure overload protection diaphragm 4, the negative pressure overload protection diaphragm 5, and the negative pressure detection surface. When the positive pressure isolation diaphragm 2 is subjected to pressure, the pressure first acts on the positive pressure overload protection diaphragm 4, and then transmits the pressure to the negative pressure overload protection diaphragm 5 and the positive pressure detection surface. The first overload protection diaphragm 21 and the second overload protection diaphragm 22 deform together to reduce the instantaneous pressure on the positive pressure detection surface. When the negative pressure isolation diaphragm 3 is subjected to pressure, the pressure first acts on the negative pressure overload protection diaphragm 5, and then transmits the pressure to the positive pressure overload protection diaphragm 4 and the negative pressure detection surface. The first overload protection diaphragm 21 and the second overload protection diaphragm 22 deform together to reduce the instantaneous pressure on the negative pressure detection surface.
[0040] In this embodiment, the differential pressure sensor's substrate 1 is an integrated structure, eliminating the need for welding. This gives the substrate 1 high structural strength, avoids weak points, and prevents data deviation caused by stress deformation, thus improving the measurement accuracy of the differential pressure sensor. The integrated structure also simplifies the manufacturing process of the substrate 1, reducing its manufacturing cost. By setting a positive overload protection diaphragm 4 and a negative overload protection diaphragm 5, overload protection is provided for the differential pressure chip 7, preventing excessive pressure from breaking it down. Furthermore, the positive overload protection diaphragm 4 and the negative overload protection diaphragm 5 deform together to reduce the stress generated at the differential pressure chip 7. Both can generate sufficient deformation together in a short time to achieve a good protection effect for the differential pressure chip 7, giving the differential pressure sensor better overload resistance.
[0041] Optionally, the positive pressure overload protection diaphragm 4 and the negative pressure overload protection diaphragm 5 are located on opposite sides of the substrate 1, with the positive pressure overload protection diaphragm 4 positioned between the positive pressure isolation diaphragm 2 and the substrate 1, and the negative pressure overload protection diaphragm 5 positioned between the negative pressure isolation diaphragm 3 and the substrate 1. This arrangement facilitates the installation of the positive pressure overload protection diaphragm 4 and the negative pressure overload protection diaphragm 5. Specifically, each of the opposite sides of the substrate 1 has an inwardly recessed receiving groove, and the positive pressure overload protection diaphragm 4 and the negative pressure overload protection diaphragm 5 are respectively installed in the corresponding receiving groove. Specifically, both the positive pressure overload protection diaphragm 4 and the negative pressure overload protection diaphragm 5 are welded to the substrate 1.
[0042] Optionally, the positive pressure overload protection diaphragm 4 and the negative pressure overload protection diaphragm 5 are symmetrically arranged about the central axis of the substrate 1. This arrangement further improves the overload resistance of the differential pressure sensor and enhances the versatility of the positive and negative pressure end fittings of the substrate 1, thereby reducing the manufacturing cost of the differential pressure sensor.
[0043] Optionally, see Figures 2 to 7 The positive pressure pipeline assembly 8 includes a first positive pressure pipe 81, a second positive pressure pipe 82, and a third positive pressure pipe 83. The pressure-conducting fluid in the first positive pressure pipe 81 flows between the positive pressure isolation diaphragm 2 and the positive pressure overload protection diaphragm 4. The pressure-conducting fluid in the second positive pressure pipe 82 flows to the side of the negative pressure overload protection diaphragm 5 facing away from the negative pressure isolation diaphragm 3. The pressure-conducting fluid in the third positive pressure pipe 83 flows to the positive pressure detection surface. The first positive pressure pipe 81, the second positive pressure pipe 82, and the third positive pressure pipe 83 are interconnected. Therefore, when the positive pressure isolation diaphragm 2 is subjected to pressure, the pressure first acts on the positive pressure overload protection diaphragm 4 through the first positive pressure pipe 81, and then is transmitted through the second positive pressure pipe 82 and the third positive pressure pipe 83, respectively acting on the negative pressure overload protection diaphragm 5 and the positive pressure detection surface.
[0044] Specifically, the first positive pressure tube 81 and the second positive pressure tube 82 are both disposed within the substrate 1, and the third positive pressure tube 83 is partially located within the substrate 1 and partially connected to the positive pressure detection surface via the differential pressure silicon seat 6. Both ends of the first positive pressure tube 81 are connected to the second positive pressure tube 82 and the third positive pressure tube 83, so that the pressure-conducting fluid in the first positive pressure tube 81 can fully conduct pressure.
[0045] Optionally, the negative pressure pipeline assembly 9 includes a first negative pressure pipe 91, a second negative pressure pipe 92, and a third negative pressure pipe 93. The pressure-conducting fluid in the first negative pressure pipe 91 flows between the negative pressure isolation diaphragm 3 and the negative pressure overload protection diaphragm 5. The pressure-conducting fluid in the second negative pressure pipe 92 flows to the side of the positive pressure overload protection diaphragm 4 opposite to the positive pressure isolation diaphragm 2. The pressure-conducting fluid in the third negative pressure pipe 93 flows to the negative pressure detection surface. The first negative pressure pipe 91, the second negative pressure pipe 92, and the third negative pressure pipe 93 are interconnected. Therefore, when the negative pressure isolation diaphragm 3 is subjected to pressure, the pressure first acts on the negative pressure overload protection diaphragm 5 through the first negative pressure pipe 91, and then is transmitted through the second negative pressure pipe 92 and the third negative pressure pipe 93, respectively acting on the positive pressure overload protection diaphragm 4 and the negative pressure detection surface.
[0046] Specifically, the first negative pressure tube 91 and the second negative pressure tube 92 are both disposed within the base 1, and the third negative pressure tube 93 is partially located within the base 1 and partially connected to the negative pressure detection surface via the differential pressure silicon seat 6. Both ends of the first negative pressure tube 91 are connected to the second negative pressure tube 92 and the third negative pressure tube 93, so that the pressure-conducting fluid in the first negative pressure tube 91 can fully conduct pressure.
[0047] Optionally, see Figure 8 A groove 100 is provided on the substrate 1. The differential pressure silicon holder 6 extends into the groove 100 and fits against the inner wall of the groove 100, improving the connection strength and stability between the differential pressure silicon holder 6 and the substrate 1. At the same time, it reduces the number of mating parts, making the structure of the differential pressure sensor simpler and facilitating the installation of the differential pressure silicon holder 6. A receiving cavity is formed between the differential pressure silicon holder 6 and the inner wall of the groove 100, and the differential pressure chip 7 is located in the receiving cavity, facilitating the installation of the differential pressure chip 7.
[0048] Specifically, the bottom portion of the differential pressure silicon holder 6 extends into the groove 100 and fits against the inner wall of the groove 100, while the other portion abuts against the end of the groove 100, making the receiving cavity a sealed space. The differential pressure silicon holder 6 is welded to the substrate 1, giving the differential pressure silicon holder 6 and the substrate 1 a high connection strength.
[0049] Optionally, the differential pressure sensor also includes a fixing member 10, which is connected to the differential pressure silicon base 6, and the differential pressure chip 7 is connected to the fixing member 10. The fixing member 10 isolates the positive pressure detection surface from the negative pressure detection surface. By setting the fixing member 10, the differential pressure chip 7 can be easily fixed, while isolating the positive pressure detection surface from the negative pressure detection surface.
[0050] Specifically, the fixing member 10 is connected to the side of the differential pressure chip 7 where the positive pressure detection surface is provided. The fixing member 10 has a through hole that communicates with the third positive pressure tube 83, allowing the pressure-conducting fluid in the third positive pressure tube 83 to flow through the through hole to the positive pressure detection diaphragm. The diameter of the end of the through hole facing the fixing member 10 is smaller than the diameter of the end near the differential pressure chip 7, providing a larger contact area between the pressure-conducting fluid and the positive pressure detection diaphragm for sufficient contact. The fixing member 10 is made of insulating material to prevent electrical conductivity between the fixing member 10 and the differential pressure silicon base 6. The fixing member 10 is bonded to the differential pressure silicon base 6. The negative pressure detection surface faces the bottom of the groove 100, and the third negative pressure tube 93 communicates with the receiving cavity, allowing the pressure-conducting fluid in the third negative pressure tube 93 to flow through the receiving cavity to the negative pressure detection diaphragm.
[0051] Optionally, the differential pressure sensor also includes an isolation sleeve 11, which is fitted onto the differential pressure silicon base 6 and connected to the substrate 1. The isolation sleeve 11 can isolate assembly stress and external heat, reducing the impact of assembly stress and external heat on the differential pressure chip 7 and improving the accuracy of the detection results of the differential pressure chip 7.
[0052] Specifically, the isolation sleeve 11 is welded to the differential pressure silicon substrate 6. A gap is provided between the inner wall of the isolation sleeve 11 and the outer peripheral wall of the differential pressure silicon substrate 6, forming an isolation space between the isolation sleeve 11 and the differential pressure silicon substrate 6, further reducing the impact of assembly stress and external heat on the differential pressure chip 7. At the same time, the pressure-conducting fluid can flow into the differential pressure silicon substrate 6 from the gap between the inner wall of the isolation sleeve 11 and the outer peripheral wall of the differential pressure silicon substrate 6, and then flow to the positive pressure detection surface.
[0053] Optionally, the differential pressure sensor also includes a connector 12, which is sleeved on the isolation sleeve 11 and has external threads. By providing the connector 12, it is convenient to connect the differential pressure sensor to the external housing. Since the connector 12 is sleeved on the isolation sleeve 11, it does not directly contact the differential pressure silicon base 6, which can avoid the transmission of assembly stress during the assembly of the connector 12 and the influence of external heat on the differential pressure chip 7.
[0054] Optionally, the connector 12 is welded to the base 1 and the isolation sleeve 11 respectively, so that the connector 12 has better connection strength and connection stability.
[0055] Optionally, the differential pressure sensor also includes a positive pressure filling pipe 13 and a negative pressure filling pipe 14. Both the positive pressure filling pipe 13 and the negative pressure filling pipe 14 are disposed on the differential pressure silicon base 6. One end of the positive pressure filling pipe 13 is connected to an external pressure guiding fluid inlet device, and the other end is connected to a third positive pressure pipe 83. The positive pressure filling pipe 13 is used to fill pressure guiding fluid into the positive pressure pipeline assembly 8. One end of the negative pressure filling pipe 14 is connected to an external pressure guiding fluid inlet device, and the other end is connected to a third negative pressure pipe 93. The negative pressure filling pipe 14 is used to fill pressure guiding fluid into the negative pressure pipeline assembly 9.
[0056] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A differential pressure sensor, characterized by, The application relates to a differential pressure sensor, which comprises the following components: a base (1); a positive pressure isolation diaphragm (2) and a negative pressure isolation diaphragm (3) arranged on opposite sides of the base (1) respectively; a positive pressure overload protection diaphragm (4) and a negative pressure overload protection diaphragm (5) arranged on the base (1); a differential pressure silicon seat (6) connected to the base (1), wherein a differential pressure chip (7) is arranged on the differential pressure silicon seat (6), and the differential pressure chip (7) has a positive pressure detection surface and a negative pressure detection surface; a positive pressure pipeline assembly (8) and a negative pressure pipeline assembly (9), wherein each of the positive pressure pipeline assembly (8) and the negative pressure pipeline assembly (9) contains a pressure guide liquid, the pressure guide liquid in the positive pressure pipeline assembly (8) flows between the positive pressure isolation diaphragm (2), the positive pressure overload protection diaphragm (4), the negative pressure overload protection diaphragm (5) and the positive pressure detection surface, and the pressure guide liquid in the negative pressure pipeline assembly (9) flows between the negative pressure isolation diaphragm (3), the positive pressure overload protection diaphragm (4), the negative pressure overload protection diaphragm (5) and the negative pressure detection surface. The positive pressure overload protection diaphragm (4) and the negative pressure overload protection diaphragm (5) are arranged on opposite sides of the base (1) respectively, the positive pressure overload protection diaphragm (4) is arranged between the positive pressure isolation diaphragm (2) and the base (1), and the negative pressure overload protection diaphragm (5) is arranged between the negative pressure isolation diaphragm (3) and the base (1). The positive pressure overload protection diaphragm (4) and the negative pressure overload protection diaphragm (5) are symmetrically arranged about the central axis of the base (1). The positive pressure pipeline assembly (8) comprises a first positive pressure pipe (81), a second positive pressure pipe (82) and a third positive pressure pipe (83), the pressure guide liquid in the first positive pressure pipe (81) flows between the positive pressure isolation diaphragm (2) and the positive pressure overload protection diaphragm (4), the pressure guide liquid in the second positive pressure pipe (82) flows to one side of the negative pressure overload protection diaphragm (5) which is away from the negative pressure isolation diaphragm (3), the pressure guide liquid in the third positive pressure pipe (83) flows to the positive pressure detection surface, and the first positive pressure pipe (81), the second positive pressure pipe (82) and the third positive pressure pipe (83) are communicated with each other. The negative pressure pipeline assembly (9) comprises a first negative pressure pipe (91), a second negative pressure pipe (92) and a third negative pressure pipe (93), the pressure guide liquid in the first negative pressure pipe (91) flows between the negative pressure isolation diaphragm (3) and the negative pressure overload protection diaphragm (5), the pressure guide liquid in the second negative pressure pipe (92) flows to one side of the positive pressure overload protection diaphragm (4) which is away from the positive pressure isolation diaphragm (2), the pressure guide liquid in the third negative pressure pipe (93) flows to the negative pressure detection surface, and the first negative pressure pipe (91), the second negative pressure pipe (92) and the third negative pressure pipe (93) are communicated with each other. 2. The differential pressure sensor of claim 1, wherein, 3. The differential pressure sensor of claim 2, wherein, 4. The differential pressure sensor of claim 2, wherein, 5. The differential pressure sensor of claim 2, wherein, 6. The differential pressure sensor of claim 1, wherein, The base body (1) is provided with a recess (100), the differential pressure silicon seat (6) partially extends into the recess (100) and is attached to the inner wall of the recess (100), a containing cavity is formed between the differential pressure silicon seat (6) and the inner wall of the recess (100), and the differential pressure chip (7) is located in the containing cavity.
7. The differential pressure sensor of claim 6, wherein, The differential pressure sensor further comprises a fixing member (10), the fixing member (10) is connected to the differential pressure silicon seat (6), the differential pressure chip (7) is connected to the fixing member (10), and the fixing member (10) separates the positive pressure detection surface and the negative pressure detection surface.
8. The differential pressure sensor of claim 7, wherein, The differential pressure sensor further comprises an isolation sleeve (11), the isolation sleeve (11) is sleeved on the differential pressure silicon seat (6), and the isolation sleeve (11) is connected to the base body (1).
9. The differential pressure sensor of claim 8, wherein, The differential pressure sensor further comprises a connecting member (12), the connecting member (12) is sleeved on the isolation sleeve (11), and the connecting member (12) is provided with external threads.
10. The differential pressure sensor of claim 9, wherein, The connecting member (12) is welded with the base body (1) and the isolation sleeve (11) respectively.