Differential pressure sensor

Abstract

The utility model belongs to the technical field of sensitive components, and discloses a differential pressure sensor. The differential pressure sensor comprises a base, two liquid receiving structures, a liquid receiving diaphragm and a pressure sensing chip, the liquid receiving structures are arranged on the base, the liquid receiving diaphragm is arranged on the liquid receiving structures, the base is replaced by the liquid receiving structures to be connected with the liquid receiving diaphragm, the liquid receiving structures are made of different materials according to actual needs, and the pressure sensing chip is arranged on the liquid receiving diaphragm. The liquid receiving structure is connected to the base, and the base does not need to be reprocessed by replacing a base material, so that the universality of the base is improved, and the input cost is effectively reduced; the two liquid receiving structures are arranged, the first channels of the liquid receiving structures are communicated with the second channel of the base, the pressure sensing chip is arranged in the base, and the liquid receiving diaphragm can push the pressure conduction liquid to flow towards the pressure sensing chip after sensing the pressure of the to-be-detected liquid, so that the detection of the pressure difference between the two ends of the pressure sensing chip is completed.

Description

Technical Field

[0001] The utility model relates to the technical field of sensitive components, in particular to a differential pressure sensor. Background Art

[0002] Differential pressure sensors are usually used to measure the liquid level in a closed container. They use the pressure difference generated by the liquid's own gravity to measure the liquid level in the container. A pressure-sensing chip is set in the differential pressure sensor. The two ends of the pressure-sensing chip are connected to the high-pressure cavity and the low-pressure cavity respectively. The pressure-sensing chip can sense the pressure difference between the high-pressure cavity and the low-pressure cavity.

[0003] The differential pressure sensor includes a base body and a mounting seat arranged on the base body, the pressure sensing chip is arranged in the mounting seat, and a liquid-contacting diaphragm is welded on the base body, which can push the pressure-conducting liquid in the corresponding high-pressure cavity or low-pressure cavity to flow toward the pressure sensing chip. When the welding compatibility of the material used for the base body is poor, the weld at the welding point between the liquid-contacting diaphragm and the base body is prone to cracking, which affects the service life of the differential pressure sensor. Therefore, different materials need to be selected to process the base body to meet the use requirements of different application scenarios, resulting in poor versatility of the base body and high processing investment costs.

[0004] That is, in the prior art, different materials need to be selected to process the base body to meet the requirements of different application scenarios, which has the disadvantages of poor versatility of the base body and high processing investment cost. Utility Model Content

[0005] The utility model aims to provide a differential pressure sensor to solve the problems of poor universality of the existing differential pressure sensor base body and high processing investment cost.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] The utility model provides a differential pressure sensor, which comprises:

[0008] A base, wherein a pressure-sensing chip is arranged in the base;

[0009] Two liquid contact structures are separately connected to the base, and the liquid contact structures are provided with liquid contact diaphragms for sensing the pressure of the liquid to be measured;

[0010] A first channel is provided in the liquid contact structure, and a second channel is provided in the base. The first channel and the second channel are connected to allow pressure transmission liquid to flow between the liquid contact diaphragm and the pressure sensing chip.

[0011] As an optional technical solution of a differential pressure sensor, the liquid contact structure includes:

[0012] A liquid receiving platform connected to the base and the liquid receiving membrane, wherein the first channel is disposed in the liquid receiving platform;

[0013] The liquid receiving pipe is sealedly connected to the liquid receiving platform and the base and communicates with the first channel and the second channel.

[0014] As an optional technical solution of the differential pressure sensor, one side of the liquid receiving platform is attached to the base, the liquid receiving membrane is arranged on the other side of the liquid receiving platform, and the first channel runs through the liquid receiving platform.

[0015] As an optional technical solution of the differential pressure sensor, the first channel forms an insertion opening on the outer surface of the liquid receiving platform, one end of the liquid receiving tube is inserted into the insertion opening and the outer peripheral wall is sealed and connected to the outer surface of the liquid receiving platform.

[0016] As an optional technical solution for a differential pressure sensor, a side of the base facing the liquid receiving platform is provided with an avoidance groove for avoiding a sealing connection of the liquid receiving pipe.

[0017] As an optional technical solution of the differential pressure sensor, a limit surface is provided in the first channel, and the end of the liquid receiving tube abuts against the limit surface.

[0018] As an optional technical solution for a differential pressure sensor, the liquid receiving pipe is made of stainless steel.

[0019] As an optional technical solution of the differential pressure sensor, a positioning groove is provided on the base, and the liquid contact structure is at least partially accommodated in the positioning groove.

[0020] As an optional technical solution of a differential pressure sensor, the base includes a base and a mounting seat arranged on the base;

[0021] The pressure sensing chip is arranged in the mounting seat, and an accommodating cavity communicated with the second channel is arranged between the base and the mounting seat, and a damping pin is slidably arranged in the accommodating cavity.

[0022] As an optional technical solution of the differential pressure sensor, the length of the damping pin is greater than the depth of the accommodating cavity located in the base.

[0023] Beneficial effects:

[0024] The utility model provides a differential pressure sensor, which comprises a base, two liquid contact structures, a liquid contact diaphragm and a pressure sensing chip. The pressure sensing chip is arranged in the base, two separate liquid contact structures are connected to the base, a liquid contact diaphragm for sensing the pressure of the liquid to be measured is arranged on the liquid contact structure, a first channel is arranged in the liquid contact structure, and a second channel is arranged in the base, and the first channel and the second channel are connected for the pressure transmission liquid to flow between the liquid contact diaphragm and the pressure sensing chip. By arranging the liquid contact structure on the base, arranging the liquid contact diaphragm on the liquid contact structure, and using the liquid contact structure to replace the base and connect the liquid contact diaphragm, it is only necessary to use different materials to make the liquid contact structure according to actual needs, and connect the liquid contact structure to the base, without changing the base material and reprocessing the base, thereby improving the versatility of the base and effectively reducing the investment cost; by arranging the two liquid contact structures, the first channel of the liquid contact structure is connected with the second channel of the base, and after the liquid contact diaphragm senses the pressure of the liquid to be measured, the liquid contact diaphragm can push the pressure transmission liquid to flow toward the pressure sensing chip, thereby completing the detection of the pressure difference at both ends of the pressure sensing chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a differential pressure sensor provided by an embodiment of the utility model;

[0026] Figure 2 The cross-sectional view of the differential pressure sensor provided by the embodiment of the utility model Figure 1 ;

[0027] Figure 3 The cross-sectional view of the differential pressure sensor provided by the embodiment of the utility model Figure 2 .

[0028] In the figure:

[0029] 11. Base; 111. High-pressure end base; 112. Low-pressure end base; 113. Transfer table; 114. Silicon seat; 115. Sleeve; 116. Avoidance groove; 12. Liquid receiving table; 13. Liquid receiving pipe;

[0030] 2. High-pressure channel; 21. First high-pressure channel; 22. Second high-pressure channel; 23. Third high-pressure channel;

[0031] 3. Low-pressure channel; 31. First low-pressure channel; 32. Second low-pressure channel; 33. Third low-pressure channel; 34. Fourth low-pressure channel; 35. Fifth low-pressure channel;

[0032] 4. Damping pin; 5. Center diaphragm; 6. Liquid-contacting diaphragm; 7. Pressure-sensing chip. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0034] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0036] In the description of this embodiment, the terms "upper", "lower", "right", etc., are based on the directions or positions shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0037] like Figures 1 to 3 As shown, this embodiment provides a differential pressure sensor, which includes a base 11, two liquid-contacting structures, a liquid-contacting diaphragm 6 and a pressure-sensitive chip 7. The base 11 is provided with a pressure-sensitive chip 7, and the two liquid-contacting structures are separately connected to the base 11. The liquid-contacting diaphragm 6 for sensing the pressure of the liquid to be measured is provided on the liquid-contacting structure; a first channel is provided in the liquid-contacting structure, and a second channel is provided in the base 11. The first channel and the second channel are connected to allow pressure transmission liquid to flow between the liquid-contacting diaphragm 6 and the pressure-sensitive chip 7.

[0038] By arranging a liquid contacting structure on the base 11, arranging the liquid contacting diaphragm 6 on the liquid contacting structure, and utilizing the liquid contacting structure to replace the base 11 to be connected with the liquid contacting diaphragm 6, it is only necessary to use different materials to make the liquid contacting structure according to actual needs, and connect the liquid contacting structure to the base 11, without replacing the material of the base 11 and reprocessing the base 11, thereby improving the versatility of the base 11 and effectively reducing the investment cost; by arranging two liquid contacting structures, the first channel of the liquid contacting structure is connected with the second channel of the base 11, and after the liquid contacting diaphragm 6 senses the pressure of the liquid to be measured, the liquid contacting diaphragm 6 can push the pressure transmission liquid to flow toward the pressure sensing chip 7, thereby completing the detection of the pressure difference at both ends of the pressure sensing chip 7.

[0039] Specifically, the liquid receiving structure includes a liquid receiving platform 12 and a liquid receiving pipe 13. The liquid receiving platform 12 is connected to the base 11 and the liquid receiving membrane 6. The first channel is arranged in the liquid receiving platform 12. The liquid receiving pipe 13 is sealed and connected to the liquid receiving platform 12 and the base 11 and connects the first channel and the second channel. By arranging the second channel on the liquid receiving platform 12 and arranging the liquid receiving pipe 13 to connect the first channel and the second channel, the liquid receiving pipe 13 is sealed and connected so as to ensure the sealing of the connection and prevent the pressure transmission liquid from leaking from the gap at the connection position of the second channel and the third channel.

[0040] In the prior art, the base is made of stainless steel. If the liquid-contacting diaphragm is directly welded to the base, the materials at the welding point between the liquid-contacting diaphragm and the base will be re-fused, resulting in the weld being easy to crack and having poor corrosion resistance. To solve this problem, the conventional practice is to use special materials to manufacture the entire base according to actual conditions, and then weld the liquid-contacting diaphragm to the base, resulting in poor versatility of the base, expensive special materials, and high processing investment costs.

[0041] In this embodiment, the base 11 is made of stainless steel, such as SUS316 stainless steel; the liquid receiving platform 12 is made of a special material with good welding compatibility, so that the liquid receiving membrane 6 can be welded to the liquid receiving platform 12. By providing the liquid receiving platform 12 instead of the base 11, the liquid receiving membrane 6 is welded to the liquid receiving platform 12, so that the processed base 11 can be applied to different application scenarios, and it is only necessary to use special materials to process the liquid receiving platform 12 according to the actual application situation, and then weld the liquid receiving platform 12 to the base 11, which effectively saves the investment cost; the liquid receiving platform 12 made of special materials has good welding compatibility, and the welding position is not easy to crack, thereby ensuring the corrosion resistance of the welding position.

[0042] Optionally, one side of the liquid receiving platform 12 is fitted on the base 11, the liquid receiving membrane 6 is arranged on the other side of the liquid receiving platform 12, and the first channel runs through the liquid receiving platform 12. By respectively arranging the liquid receiving membranes 6 on both sides of the liquid receiving platform 12, the liquid to be tested can directly contact the liquid receiving membranes 6 and maintain a large contact area; the pressure transmission liquid runs through the liquid receiving platform 12, and the liquid receiving membrane 6 senses the pressure of the liquid to be tested and generates deformation to push the pressure transmission liquid in the first channel to flow.

[0043] Specifically, the base 11 includes a substrate and a mounting seat arranged on the substrate, the substrate includes a high-pressure end substrate 111 and a low-pressure end substrate 112 connected to the high-pressure end substrate 111, and a central diaphragm 5 is arranged between the high-pressure end substrate 111 and the low-pressure end substrate 112; the mounting seat is arranged on the high-pressure end substrate 111 and the low-pressure end substrate 112, and the pressure sensing chip 7 is arranged in the mounting seat.

[0044] In this embodiment, two liquid receiving platforms 12 are respectively provided on both sides of the base 11, and the two liquid receiving platforms 12 are respectively connected to the high-pressure end matrix 111 and the low-pressure end matrix 112; two second channels are provided in the base 11, and the two second channels are respectively connected to the first channels of the two liquid receiving platforms 12 to form a high-pressure channel 2 and a low-pressure channel 3, the high-pressure channel 2 is partially provided in the high-pressure end matrix 111, and the low-pressure channel 3 is partially provided in the low-pressure end matrix 112, and the central diaphragm 5 separates the high-pressure channel 2 and the low-pressure channel 3; pressure transmission liquid is provided in both the high-pressure channel 2 and the low-pressure channel 3.

[0045] Optionally, the high-pressure end substrate 111 is welded to the low-pressure end substrate 112 , and the two liquid receiving platforms 12 are respectively welded to the high-pressure end substrate 111 and the low-pressure end substrate 112 ; the pressure transmission liquid may be silicone oil.

[0046] In order to ensure the stability of the position of the liquid receiving platform 12, positioning grooves are provided on the high-pressure end substrate 111 and the low-pressure end substrate 112, and the liquid receiving platform 12 is at least partially accommodated in the positioning grooves. By providing the positioning grooves to limit the installation position of the liquid receiving platform 12, it is beneficial to ensure that the liquid receiving platform 12 is accurately connected with the high-pressure end substrate 111 or the low-pressure end substrate 112, and ensure that the pressure transmission liquid can flow between the pressure sensing chip 7 and the liquid receiving diaphragm 6. In this embodiment, the liquid receiving platform 12 is in a truncated cone shape, and the positioning groove is a circular groove.

[0047] Furthermore, the first channel is formed with an insertion opening on the outer surface of the liquid receiving platform 12, one end of the liquid receiving tube 13 is inserted into the insertion opening and the outer peripheral wall is sealed and connected to the outer surface of the liquid receiving platform 12. In this embodiment, one end of the liquid receiving tube 13 is inserted into the insertion opening and the outer peripheral wall is brazed and welded to the outer surface of the liquid receiving platform 12. By inserting and connecting the liquid receiving tube 13 in the first channel and brazing it to the liquid receiving platform 12, the characteristics of high strength and good sealing of brazing connection are utilized, so that the liquid receiving tube 13 can be connected to the first channel, and the connection between the liquid receiving tube 13 and the first channel can be kept sealed, thereby preventing the pressure transmission liquid from leaking from the connection gap between the liquid receiving tube 13 and the first channel.

[0048] Optionally, the first channel has a limit surface, and the end of the liquid receiving tube 13 abuts against the limit surface. By setting the limit surface in the first channel of the liquid receiving platform 12, the depth of the liquid receiving tube 13 inserted into the first channel is limited, ensuring the stability of the installation position of the liquid receiving tube 13.

[0049] Specifically, the first channel includes a connected liquid receiving section and an insertion section, the liquid receiving section is located between the liquid receiving membrane 6 and the insertion section, the liquid receiving tube 13 is inserted in the insertion section, the inner diameter of the insertion section is larger than the inner diameter of the liquid receiving section, and a limit surface is formed between the insertion section and the liquid receiving section; the insertion section matches the outer wall of the liquid receiving tube 13. Among them, the inner diameter of the liquid receiving tube 13 is equal to or slightly larger than the inner diameter of the liquid receiving section, so that after the liquid receiving tube 13 is installed, the pressure transmission liquid can flow smoothly in the liquid receiving section and the liquid receiving tube 13. In this embodiment, the liquid receiving tube 13 is a round tube; the cross section of the first channel is circular.

[0050] Furthermore, a relief groove 116 is provided on one side of the base 11 facing the liquid receiving platform 12, for evading the sealed connection of the liquid receiving pipe 13. After the liquid receiving pipe 13 and the liquid receiving platform 12 are brazed, a brazing seam will be formed at the welding position, and the relief groove 116 can accommodate the brazing seam. By providing the relief groove 116, the liquid receiving platform 12 and the base 11 can be fitted to avoid a gap between the liquid receiving platform 12 and the base 11, and the liquid receiving pipe 13 can also be welded.

[0051] Optionally, one end of the liquid receiving pipe 13 is brazed and sealed with the liquid receiving platform 12, and the other end of the liquid receiving pipe 13 is welded to the high-pressure end substrate 111 or the low-pressure end substrate 112 by ordinary welding; the liquid receiving pipe 13 is made of stainless steel, such as 316L stainless steel. By arranging the liquid receiving pipe 13 to be welded to the base 11, it is possible to effectively prevent the pressure transmission liquid from leaking from the gap at the connection between the liquid receiving pipe 13 and the second channel of the base 11.

[0052] In order to reserve welding positions, in this embodiment, the high-pressure end substrate 111 and the low-pressure end substrate 112 are both provided with avoidance grooves 116, and the avoidance grooves 116 are arranged opposite to each other on both sides of the high-pressure end substrate 111 or the low-pressure end substrate 112, and the two ends of the liquid receiving pipe 13 are respectively welded to the base 11 and the liquid receiving platform 12 at the avoidance grooves 116; one end of the liquid receiving pipe 13 is brazed and sealed with the liquid receiving platform 12, and the other end of the liquid receiving pipe 13 is generally welded to the base 11. It can be understood that a suitable welding method can be selected according to the materials of the base 11, the liquid receiving platform 12 and the liquid receiving pipe 13.

[0053] In this embodiment, the avoidance groove 116 is a circular groove; two first channels are provided on each liquid receiving platform 12; four liquid receiving pipes 13 are provided, and four avoidance grooves 116 are provided on the high-pressure end substrate 111 and the low-pressure end substrate 112.

[0054] Further, the mounting base includes a transfer platform 113, a silicon base 114 connected to the transfer platform 113, and a sleeve 115 sleeved outside the transfer platform 113 and the silicon base 114, the sleeve 115 is fixedly connected to the high-voltage end substrate 111 and the low-voltage end substrate 112, and the pressure sensing chip 7 is located between the transfer platform 113 and the silicon base 114. Optionally, the transfer platform 113 is welded to the high-voltage end substrate 111, the silicon base 114 is welded to the transfer platform 113, and the sleeve 115 is welded to the high-voltage end substrate 111 and the low-voltage end substrate 112.

[0055] In this embodiment, a receiving cavity connected to the high-pressure channel 2 is provided between the high-pressure end base 111 and the transfer platform 113, and a damping pin 4 is slidably provided in the receiving cavity, and the length of the damping pin 4 is less than the depth of the receiving cavity; and a pressure transmission liquid is provided in the receiving cavity. When the liquid-contacting diaphragm 6 encounters a large pressure, it pushes the pressure transmission liquid in the high-pressure channel 2 to flow into the receiving cavity, and the pressure transmission liquid pushes the damping pin 4 to slide in the receiving cavity and continues to transmit along the damping pin 4, playing a buffering role to prevent the pressure-sensitive chip 7 from being damaged.

[0056] Optionally, a spiral channel is provided on the outer surface of the damping pin 4; the length of the damping pin 4 is greater than the depth of the accommodating cavity in the high-pressure end substrate 111. By providing the spiral channel, the flow distance of the pressure transmission fluid in the spiral channel is increased, thereby improving the buffering effect; by setting the length of the damping pin 4 to be greater than the depth of the accommodating cavity in the high-pressure end substrate 111, the damping pin 4 can partially protrude from the high-pressure end substrate 111, and the damping pin 4 can play a positioning role when welding the adapter 113.

[0057] See also Figure 2The high-pressure channel 2 includes a first high-pressure channel 21, a second high-pressure channel 22 and a third high-pressure channel 23 which are connected in sequence, and the third high-pressure channel 23 is connected to the accommodating chamber; the first high-pressure channel 21 is composed of a first channel on the liquid receiving platform 12 and a liquid receiving tube 13. The low-pressure channel 3 includes a first low-pressure channel 31, a second low-pressure channel 32, a third low-pressure channel 33, a fourth low-pressure channel 34 and a fifth low-pressure channel 35 which are connected in sequence; the first low-pressure channel 31 is composed of a first channel on the liquid receiving platform 12 and a liquid receiving tube 13; the fourth low-pressure channel 34 is located between the outer circumference of the transfer platform 113 and the silicon seat 114 and the inner circumference of the sleeve 115; the fifth low-pressure channel 35 is arranged in the silicon seat 114.

[0058] When the liquid-contacting diaphragm 6 on one side of the high-pressure end substrate 111 is subjected to pressure, the pressure transmission liquid is pushed to pass through the first high-pressure channel 21, the second high-pressure channel 22, the third high-pressure channel 23 and the accommodating cavity in sequence, pushing the damping pin 4, and the pressure transmission liquid reaches one end of the pressure-sensitive chip 7 through the spiral channel on the surface of the damping pin 4; when the liquid-contacting diaphragm 6 on one side of the low-pressure end substrate 112 is subjected to pressure, the pressure transmission liquid is pushed to pass through the first low-pressure channel 31, the second low-pressure channel 32, the third low-pressure channel 33, the fourth low-pressure channel 34 and the fifth low-pressure channel 35 in sequence to reach the other end of the pressure-sensitive chip 7, so that the pressure-sensitive chip 7 can sense the pressure difference between the high-pressure channel 2 and the low-pressure channel 3.

[0059] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the scope of protection of the present invention. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. A differential pressure sensor, characterized in that: include: A base (11), wherein a pressure sensing chip (7) is arranged in the base (11); Two liquid contact structures are separately connected to the base (11), and the liquid contact structures are provided with liquid contact diaphragms (6) for sensing the pressure of the liquid to be measured; A first channel is provided in the liquid contact structure, and a second channel is provided in the base (11). The first channel and the second channel are connected to allow pressure transmission liquid to flow between the liquid contact diaphragm (6) and the pressure sensing chip (7).

2. The differential pressure sensor according to claim 1, characterized in that: The liquid contact structure comprises: A liquid receiving platform (12) connected to the base (11) and the liquid receiving membrane (6), wherein the first channel is arranged in the liquid receiving platform (12); A liquid receiving pipe (13) is sealedly connected to the liquid receiving platform (12) and the base (11) and communicates with the first channel and the second channel.

3. The differential pressure sensor according to claim 2, characterized in that: One side of the liquid receiving platform (12) is arranged in close contact with the base (11), the liquid receiving membrane (6) is arranged on the other side of the liquid receiving platform (12), and the first channel runs through the liquid receiving platform (12).

4. The differential pressure sensor according to claim 3, characterized in that: The first channel is formed with an insertion opening on the outer surface of the liquid receiving platform (12); one end of the liquid receiving pipe (13) is inserted into the insertion opening and the outer peripheral wall is sealed and connected to the outer surface of the liquid receiving platform (12).

5. The differential pressure sensor according to claim 4, characterized in that: A relief groove (116) is provided on one side of the base (11) facing the liquid receiving platform (12) for evading the sealing connection of the liquid receiving pipe (13).

6. The differential pressure sensor according to claim 4, characterized in that: A limiting surface is provided in the first channel, and the end of the liquid receiving pipe (13) abuts against the limiting surface.

7. The differential pressure sensor according to claim 2, characterized in that: The liquid receiving pipe (13) is made of stainless steel.

8. The differential pressure sensor according to any one of claims 1 to 7, characterized in that: The base (11) is provided with a positioning groove, and the liquid contact structure is at least partially accommodated in the positioning groove.

9. The differential pressure sensor according to any one of claims 1 to 7, characterized in that: The base (11) comprises a base body and a mounting seat arranged on the base body; The pressure sensing chip (7) is arranged in the mounting seat, and a receiving cavity communicated with the second channel is arranged between the base and the mounting seat, and a damping pin (4) is slidably arranged in the receiving cavity.

10. The differential pressure sensor according to claim 9, characterized in that: The length of the damping pin (4) is greater than the depth of the accommodating cavity located in the base body.

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