CN220490276U

CN220490276U - Pressure sensor, in particular for measuring hydrogen-containing fluids

Info

Publication number: CN220490276U
Application number: CN202322005850.8U
Authority: CN
Inventors: 王小平; 曹万; 吴林; 张超军; 施涛
Original assignee: Wuhan Finemems Inc
Current assignee: Wuhan Finemems Inc
Priority date: 2023-07-27
Filing date: 2023-07-27
Publication date: 2024-02-13
Anticipated expiration: 2033-07-27

Abstract

The present application provides a pressure sensor, which includes: the metal matrix is internally provided with a pressure cavity, the lower end of the pressure cavity is provided with an opening for receiving hydrogen-containing fluid, the upper end of the pressure cavity is sealed with an elastic diaphragm, and all or part of the inner surface of the pressure cavity is covered with an isolation layer for inhibiting diffusion of hydrogen atoms into the metal matrix; the plastic connector is arranged on the upper side of the metal matrix; a metal cylinder shell which is connected with the metal matrix and the plastic connector up and down to form a sealed installation cavity; the pressure sensing circuit is arranged on the upper surface of the diaphragm and is used for outputting a measurement signal according to the deformation of the elastic diaphragm; and the signal processing module is arranged in the mounting cavity and is used for processing the measurement signals and outputting measurement results to external equipment. The pressure sensor is particularly suitable for high-pressure and stable measurement of hydrogen-containing fluids such as hydrogen.

Description

Pressure sensor, in particular for measuring hydrogen-containing fluids

Technical Field

The present application relates to the field of pressure sensor technology, and in particular to a pressure sensor particularly suitable for measuring hydrogen-containing fluids.

Background

A metal-based thick film pressure sensor is a pressure sensor in which one side of a diaphragm of a metal substrate is exposed to a fluid and the pressure of the fluid is measured with a measurement circuit consisting of a thick film resistor or strain gauge or the like attached to the opposite side of the diaphragm. The thickness of the diaphragm can be adjusted by mechanical processing, so that the measurable pressure is up to tens of megapascals, the other side of the diaphragm is not contacted with pressure medium, and the diaphragm has high tightness, and if the variable resistor is thick film, the diaphragm can be conveniently manufactured in batch by printing and sintering. On the other hand, for a hydrogen energy automobile, a mature storage scheme is high-pressure hydrogen storage, so that the metal-based thick film pressure sensor has a good application prospect in the aspect of the hydrogen energy automobile. However, in the practical use process, hydrogen can be dissolved in metal and slowly penetrate to the other side of the membrane due to the small atomic radius, and the diffusion rate of hydrogen in the metal is accelerated with the increase of temperature. Thus, hydrogen accumulated on the other side of the diaphragm increases the reference pressure on the other side, and dissolution of hydrogen in the diaphragm also causes changes in the characteristics of the diaphragm material, which can make the measurement structure inaccurate.

The statements in this section merely provide background information related to the present application and may not constitute prior art.

Disclosure of Invention

In response to the deficiencies of the prior art, the present application provides a pressure sensor particularly adapted for measuring hydrogen-containing fluids to avoid measurement bias due to hydrogen permeation through a metal substrate.

In order to achieve the above purpose, the present application provides the following technical solutions: a pressure sensor particularly suitable for hydrogen-containing fluids, comprising:

the metal matrix is internally provided with a pressure cavity, the lower end of the pressure cavity is provided with an opening for receiving hydrogen-containing fluid, the upper end of the pressure cavity is sealed with an elastic diaphragm, and all or part of the inner surface of the pressure cavity is covered with an isolation layer for inhibiting diffusion of hydrogen atoms into the metal matrix;

the plastic connector is arranged on the upper side of the metal matrix;

a metal cylinder shell which is connected with the metal matrix and the plastic connector up and down to form a sealed installation cavity;

the pressure sensing circuit is arranged on the upper surface of the diaphragm and is used for outputting a measurement signal according to the deformation of the elastic diaphragm;

and the signal processing module is arranged in the mounting cavity and is used for processing the measurement signals and outputting measurement results to external equipment.

Preferably, the signal processing module comprises a processing circuit arranged on the flexible circuit board; the lower part of the flexible circuit board is welded with a bonding pad of the pressure measuring circuit, the upper part of the flexible circuit board is welded with a metal pin of a metal pin arranged on the connector, and the middle part of the flexible circuit board is horizontally arranged and fixed on a hard substrate; the hard substrate is supported on a first supporting piece; the lower end of the first supporting piece is supported on the upper surface of a second supporting part formed on the outer wall of the metal matrix.

Preferably, the first support member includes a cylindrical wall disposed axially up and down and a top plate fixed to an upper end of the wall; a first positioning part is formed on the first support piece, a positioning hole can be correspondingly formed on the hard substrate, and the first positioning part passes through the positioning hole in a matched manner; the conditioning element is arranged on the middle part of the flexible circuit board;

preferably, the wall is provided with at least one opening for the flexible circuit board to pass through.

Preferably, the isolating layer is a polymer.

Preferably, the polymer is polyamide, polyethylene or polytetrafluoroethylene.

Preferably, the isolating layer is obtained by coating a polymer liquid containing the polymer on the inner surface of the pressure cavity and then heating and plasticizing.

Preferably, the thickness of the isolation layer is 0.05 mm-3 mm.

Preferably, a silane layer is arranged between the inner surface of the pressure chamber and the isolating layer.

Preferably, the thickness of the silane layer is 50nm to 200nm.

Drawings

FIG. 1 is a schematic view of a pressure sensor according to a preferred embodiment of the present utility model;

reference numerals illustrate: 100. an upper surface; 101. a bottom; 102. a sidewall; 103. sealing grooves; 10. a diaphragm; 11. a pressure chamber; 12. a first support portion; 13. a second supporting part; 14. an upper surface; 15. a ring groove; 161. a gap; 16. an upper end portion; 17. an isolation layer; 18. a lower end portion; 1. a metal matrix; 210. a wall; 211. a top plate; 212. a first positioning portion; 213. an opening; 21. a first support; 22. a second support; 23. a flexible circuit board; 24. a hard substrate; 25. a conditioning element; 2. a signal processing module; 31. hemming; 32. a seal ring; 3. a metal cartridge; 401. an inner end; 402. an outer end; 403. a first positioning blind hole; 404. a circumferential positioning groove; 40. a metal pin; 41. a flange; 4. a connector; 501. a via hole; 502. a concave portion; 503. the second positioning blind hole; 51. a third positioning portion; 520. splitting grooves; 52. a second positioning portion; 5. protecting the head;

Detailed Description

The technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings. The following examples are illustrative only and are not to be construed as limiting the present application. In the following description, the same reference numerals are used to designate the same or equivalent elements, and duplicate descriptions are omitted.

In the description of the present application, it should be understood that the azimuth or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "left", "right", etc. are based on the azimuth or positional relationship shown in the drawings, or the azimuth or positional relationship in which the product of the present application is conventionally put in use, or the azimuth or positional relationship as is conventionally understood by those skilled in the art, are merely for convenience of description of the present application and for simplification of description, and are not indicative or implying that the apparatus or element to be referred to must have a specific azimuth, be configured and operated in a specific azimuth, and therefore should not be construed as limiting the present application.

In addition, the terms "mounted," "connected," "coupled," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application can be understood as appropriate by one of ordinary skill in the art.

It should be further understood that the term "and/or" as used in this specification and the corresponding claims refers to any and all possible combinations of one or more of the listed items.

As shown in fig. 1, the pressure sensor particularly suitable for hydrogen-containing fluid provided by the utility model mainly comprises a metal base body 1, a metal cylinder shell 3 and a connector 4 made of plastic. The metal cylinder housing 3 is preferably circular, and its lower end is sealed and welded to the upper surface of a ring of first support parts 12 formed on the metal base 1. The upper end of the metal cylinder housing 3 is rolled inwards to form a curled edge 31, the curled edge 31 presses down a circle of flange 41 formed at the lower end of the connector 4, and the curled edge 31 and the flange 41 are sealed through a sealing ring 32. The metal base 1, the metal cartridge 3 and the connector 4 enclose a closed installation cavity (not labeled).

The metal matrix 1 is internally provided with a pressure chamber 11, the lower end of the pressure chamber 11 is provided with an opening for receiving a hydrogen-containing fluid, the upper end is closed with an elastic diaphragm 10, and the whole or part of the inner surface (comprising a side wall 102 and a bottom 101) of the pressure chamber 11 is covered with an isolating layer 17 for inhibiting diffusion of hydrogen atoms in a medium into the metal matrix 1. The material of the isolation layer 17 may be a polymer or a metal with a low permeability. The lower end of the pressure chamber 11 is provided with an opening for receiving a hydrogen-containing fluid for introducing the pressure medium from the vessel, and the outer wall of the lower end 18 of the metal base 1 may be provided with a sealing groove 103 for receiving a sealing ring when docked with the vessel.

The surface of the diaphragm 10 facing the inner side of the mounting cavity, i.e. the upper surface 100, is provided with a pressure sensing circuit for outputting a measurement signal in dependence of the deformation of the elastic diaphragm 10. The pressure sensing circuit includes a thick film resistor or strain gauge attached to the upper surface 100 connected as a wheatstone bridge and a pad that outputs the bridge's measurement signal outwardly. The mounting cavity is internally provided with a signal processing module 2, and the signal processing module 2 is used for processing the measurement signals and then outputting measurement results to external equipment.

The pressure sensor is particularly suitable for high-pressure and stable measurement of hydrogen-containing fluid such as hydrogen because the cover layer 17 on the inner surface of the pressure chamber 11 can inhibit hydrogen atoms from diffusing in the metal matrix and penetrating the metal matrix 1 to reach the mounting chamber on the other side of the diaphragm 10, and can prevent the change of the mechanical properties of the diaphragm 10 due to hydrogen embrittlement after solid solution of hydrogen in the metal matrix 1. Corrosion can also be avoided when applied to other media that have a corrosive effect on the metal substrate, such as acidic solutions. Due to H ₂ The hydrogen atoms in S will also diffuse in the metal matrix, so the sensor of the utility model is also suitable for containing H ₂ S fluid.

Wherein the signal processing module 2 comprises processing circuitry arranged on a flexible circuit board 23. The flexible circuit board 23 may be divided into three parts, and the lower part of the flexible circuit board 23 is soldered to the pad of the pressure measurement circuit, and the upper part of the flexible circuit board 23 is soldered to the inner end 401 (i.e., lower side end) of the metal pin 40 provided on the connector 4. The middle portion of the flexible circuit board 23 is horizontally disposed and fixed on a rigid substrate 24, and the rigid substrate 24 is supported on a first support 21. The lower end of the first supporting member 21 is supported on the upper surface 14 of a second supporting portion 13 formed on the outer wall of the metal base 1. Preferably, the first support 21 includes a wall 210 having a cylindrical shape and disposed axially up and down, and a top plate 211 fixed to an upper end of the wall 210. The first supporting member 21 may have a first positioning portion 212 formed thereon, and the hard substrate 24 may have a positioning hole (not labeled) formed thereon, where the first positioning portion 212 is cooperatively inserted into the positioning hole. Conditioning elements 25 and other electronic components may be disposed on the horizontally disposed middle of the flexible circuit board 23. Preferably, at least one opening 213 is provided in the wall 210 for the lower end of the flexible circuit board 23 to pass through.

In other embodiments, the pressure sensor preferably further comprises a second support 22 arranged at the periphery of the first support 21 to support the connector 4 upwards. The upper end of the second support 22 is supported upwardly on the lower surface of a flange 41 formed at the lower end of the connector 4. The lower end of the second support 22 may be supported on the metal base 1, for example, on the upper surface 14 of the second support portion 13. Wherein, the diaphragm 10 can be arranged at the approximately round upper end 16 of the metal base 1, the upper end of the upper end 16 is radially and outwards abutted to the inner wall of the second supporting part 13, and a gap 161 is reserved between the upper end and the inner wall of the second supporting part 13, so that the base part of the diaphragm 10 has higher rigidity, and the second supporting part 13 is prevented from contacting the upper end 16 to cause measurement deviation. Preferably, a ring groove 15 is formed between the upper end portion 16 and the second supporting portion 13 to block the mounting stress of the bottom of the metal base 1 from being transferred to the diaphragm 10, so as to improve the measurement accuracy.

In other embodiments, the upper end of the connector 4 is preferably also removably attached with a protective head 5 to protect the connector metal pins 40. The protective head 5 may be a plastic piece. The outer ends 402 of the metal pins 40 extend upward through corresponding through holes 501 formed in the protection head 5 and protrude from corresponding concave portions 502 formed in the protection head 5. The protection head 5 is connected with the connector 4 in a positioning way, a first positioning blind hole 403 is formed at the upper end of the connector 4, and the lower end of the protection head 5 correspondingly protrudes downwards to form a second positioning part 52. The second positioning portion 52 is preferably cylindrical in shape, with its middle portion broken by a vertical split groove 520, forming two resilient portions that squeeze into the first positioning blind hole 403. The lower end periphery of the protection head 5 protrudes downwards to form at least one third positioning part 51. The third positioning portion 51 may be a sheet shape, and is downward-matched and extended into a circumferential positioning groove 404 correspondingly formed on the peripheral edge of the outer wall of the connector assembly 4. This allows a detachable connection to be conveniently formed. The upper end of the protection head 5 may further be formed with a second positioning blind hole 503 extending up and down to guide and position when connected to an external device.

Wherein the isolating layer 17 may be polymeric. The polymer isolation layer 17 may be obtained by spraying a powdery polymer or applying a polymer liquid to the inner surface of the pressure chamber 11, and then heating and plasticizing the polymer liquid at a proper temperature to bond the polymer liquid to the inner surface of the pressure chamber 11. Wherein, the polymer liquid can be repeatedly coated and dried on the inner surface of the pressure cavity 11 before heating to form a certain thickness, and the thickness of the isolating layer is preferably 0.05-3 mm. For example, a polymer-containing liquid such as a polyethylene dispersion or a polytetrafluoroethylene dispersion may be applied to the inner surface of the pressure chamber 11 under centrifugal conditions, heated to a suitable temperature, and plasticized.

More preferably, the inner surface of the pressure chamber 11 may be subjected to at least one silylation treatment to form a silane layer of a certain thickness before coating, for example, the silane layer may be formed by curing at about 200 ℃ after coating the inner surface of the pressure chamber 11 with a silane solution, and the total thickness of the silane layer is preferably 50 to 200nm. The silane solution described above may be prepared as follows: adding a certain amount of methanol into deionized water, slowly adding KH-560 silane, dripping acetic acid to adjust the pH value to 4.5-6.0, and continuously stirring until the solution is transparent and uniform. A silane layer can be formed between the metal substrate and the polymer layer through silanization treatment so as to improve the bonding strength of the polymer isolation layer on the metal surface.

The scope of the present disclosure is defined not by the detailed description but by the claims and their equivalents, and all modifications within the scope of the claims and their equivalents are to be construed as being included in the present disclosure.

Claims

1. A pressure sensor particularly adapted for measuring a hydrogen-containing fluid, comprising:

a metal matrix (1) with a pressure cavity (11) formed inside, wherein the lower end of the pressure cavity (11) is provided with an opening for receiving hydrogen-containing fluid, the upper end of the pressure cavity is closed with an elastic diaphragm (10), and all or part of the inner surface of the pressure cavity (11) is covered with an isolation layer (17) for inhibiting diffusion of hydrogen atoms into the metal matrix (1);

a plastic connector (4) arranged on the upper side of the metal base body (1);

a metal cylinder shell (3) which is connected with the metal base body (1) and the plastic connector (4) up and down to form a sealed installation cavity;

a pressure sensing circuit provided on an upper surface (100) of the diaphragm (10) for outputting a measurement signal according to deformation of the elastic diaphragm (10);

2. Pressure sensor according to claim 1, characterized in that the signal processing module (2) comprises a processing circuit arranged on a flexible circuit board (23); the lower part of the flexible circuit board (23) is welded with a bonding pad of the pressure measurement circuit, the upper part of the flexible circuit board is welded with a metal pin (40) of a metal pin (40) arranged on the connector (4), and the middle part of the flexible circuit board is horizontally arranged and fixed on a hard substrate (24); the hard substrate (24) is supported on a first support (21); the lower end of the first supporting member (21) is supported on the upper surface (14) of a second supporting portion (13) formed on the outer wall of the metal base (1).

3. The pressure sensor according to claim 2, wherein the first support member (21) comprises a cylindrical wall (210) disposed axially up and down and a top plate (211) fixed to an upper end of the wall (210); a first positioning part (212) is formed on the first supporting piece (21), a positioning hole can be correspondingly formed on the hard substrate (24), and the first positioning part (212) is penetrated through the positioning hole in a matching way; the conditioning element (25) is on a middle portion of the flexible circuit board (23).

4. A pressure sensor according to claim 3, characterized in that the wall (210) is provided with at least one opening (213) for the flexible circuit board (23) to pass through.

5. Pressure sensor according to any of claims 1 to 4, characterized in that the isolating layer (17) is a polymer.

6. The pressure sensor of claim 5, wherein the polymer is polyamide, polyethylene, or polytetrafluoroethylene.

7. Pressure sensor according to claim 6, characterized in that the isolating layer (17) is obtained by applying a polymer liquid containing the above-mentioned polymer to the inner surface of the pressure chamber (11) and then heating and plasticizing.

8. Pressure sensor according to any of claims 5 to 7, characterized in that the isolating layer (17) has a thickness of 0.05 mm-3 mm.

9. Pressure sensor according to any of claims 1 to 7, characterized in that a silane layer is provided between the inner surface of the pressure chamber (11) and the isolating layer (17).

10. The pressure sensor of claim 9, wherein the silane layer has a thickness of 50nm to 200nm.