CN114414128A

CN114414128A - Capacitor direct-connected pressure detection sensor

Info

Publication number: CN114414128A
Application number: CN202111520300.9A
Authority: CN
Inventors: 杨劲松; 刘庆; 王小文; 朱健; 何炳伟; 金亮
Original assignee: CHONGQING WECAN PRECISION INSTRUMENTS Co
Current assignee: CHONGQING WECAN PRECISION INSTRUMENTS Co
Priority date: 2021-12-13
Filing date: 2021-12-13
Publication date: 2022-04-29

Abstract

The invention discloses a capacitance direct-connection type pressure detection sensor, which comprises a pressure guiding module and a differential pressure sensor module, wherein two sealed sensing cavities formed by separating a diaphragm are arranged in the differential pressure sensor module, each sensing cavity is respectively connected with a pressure guiding pipe, pressure guiding channels are respectively arranged on the pressure guiding module corresponding to the two pressure guiding pipes and are communicated with the pressure guiding channels, pressure guiding inlets of the pressure guiding channels are respectively opened in the pressure guiding module, pressure taking cavities are respectively arranged in the pressure guiding module corresponding to the two pressure guiding inlets, and the two pressure guiding inlets are respectively covered with an isolation diaphragm in a sealing way; the pressure guiding module is provided with a pressure taking channel and an atmosphere channel, the pressure taking channel and the atmosphere channel are in one-to-one correspondence with the two pressure taking cavities and communicated, the outer end of the pressure taking channel penetrates out of a pressure taking joint on the pressure guiding module, and the differential pressure sensor module is provided with a static pressure compensation structure corresponding to the sensing cavity of the differential pressure sensor module. The invention has the beneficial effects that: the pressure guiding module is compact and is conveniently connected with an external pressure source to be detected, and the static pressure compensation mechanism is favorable for improving the detection precision of the sensor.

Description

Capacitor direct-connected pressure detection sensor

Technical Field

The invention relates to a pressure measuring device, in particular to a capacitance direct-connection type pressure detection sensor.

Background

The pressure sensor is widely used for measuring fluid pressure, and senses external pressure by means of a pressure sensing element, the pressure sensing element converts a pressure signal into an electric signal, and the electric signal is transmitted to a signal processing unit to obtain a pressure value. The existing pressure sensors can be classified into various types according to the difference of pressure sensitive elements, and a resistance type pressure sensor, a piezoelectric quartz crystal type pressure sensor, a capacitance type pressure sensor, and the like are common. The core detecting element of the capacitance type pressure sensor is a diaphragm type differential pressure sensor. The diaphragm type differential pressure sensor comprises two disc-shaped diaphragm seats, a measuring diaphragm is arranged between the two diaphragm seats, and the two diaphragm seats are in butt welding connection and clamp the measuring diaphragm. The measuring diaphragm and the two diaphragm seats are respectively provided with an induction cavity for containing silicon oil, the two induction cavities are respectively connected with a pressure leading pipe, and the pressure leading pipe leads external pressure to be measured into two sides of the measuring diaphragm. Due to the fact that the pressures on the two sides are different, the measuring diaphragm deforms towards the side with smaller pressure, and the deformation is reflected as the change of the capacitance signal. Due to the connections to external pressure sources and the static pressure conduction involved, existing capacitive pressure sensors are relatively complex in construction and have room for improvement in measurement accuracy.

Disclosure of Invention

In view of the above, the present invention provides a capacitive direct-coupled pressure detecting sensor.

The technical scheme is as follows:

a capacitance direct-connection pressure detection sensor comprises a pressure leading module and a differential pressure sensor module, wherein two sealed sensing cavities separated by a diaphragm are arranged in the differential pressure sensor module, each sensing cavity is respectively connected with a pressure leading pipe, pressure leading channels are respectively arranged on the pressure leading module corresponding to the two pressure leading pipes, two ends of each pressure leading channel are respectively a pressure leading inlet and a pressure leading outlet, the two pressure leading outlets are respectively arranged on the surface of the pressure leading module and are communicated with the corresponding pressure leading pipes, and the key is that,

the two pressure leading inlets are opened in the pressure leading module, pressure taking cavities are respectively formed in the pressure leading module corresponding to the two pressure leading inlets, and isolation diaphragms are respectively covered on the two pressure leading inlets in a sealing manner so as to separate the pressure taking cavities from the pressure leading inlets;

the pressure leading module is provided with a pressure taking channel and an atmospheric channel, the atmospheric channel is communicated with one of the pressure taking cavities, and the inner end of the pressure taking channel is communicated with the other pressure taking cavity;

the pressure tapping module is provided with a pressure tapping joint, and the outer end of the pressure tapping channel penetrates out of the pressure tapping joint;

and the differential pressure sensor module is provided with a static pressure compensation structure corresponding to the induction cavity of the differential pressure sensor module.

Compared with the prior art, the invention has the beneficial effects that: the pressure guiding module is more compact and is conveniently connected with an external pressure source to be detected, and the static pressure compensation mechanism is arranged to help improve the detection precision of the pressure detection sensor.

Drawings

FIG. 1 is a schematic diagram of a first perspective of the present invention;

FIG. 2 is a schematic diagram of a second perspective of the present invention;

FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2;

fig. 4 is a schematic structural diagram of a differential pressure sensor module.

Detailed Description

The present invention will be further described with reference to the following examples and the accompanying drawings.

As shown in fig. 1 to 3, a capacitance direct-coupled pressure detection sensor includes a pressure guiding module and a differential pressure sensor module 100, where the differential pressure sensor module 100 is provided with two pressure guiding pipes 160, the two pressure guiding pipes 160 are respectively communicated with two pressure guiding channels provided on the pressure guiding module, two ends of the pressure guiding channels are respectively a pressure guiding inlet and a pressure guiding outlet, the two pressure guiding outlets are respectively provided on a surface of the pressure guiding module and are in one-to-one correspondence and communication with the two pressure guiding pipes 160, both the two pressure guiding inlets are opened in the pressure guiding module, pressure taking cavities are respectively provided in the pressure guiding module corresponding to the two pressure guiding inlets, and the two pressure guiding inlets are respectively covered with an isolation diaphragm 230 in a sealing manner so as to separate the pressure taking cavities from the pressure guiding inlets. The pressure guide channel is filled with a liquid pressure transmission medium, such as silicone oil, for transmitting an external pressure to the differential pressure sensor module 100.

The pressure detecting sensor of the present embodiment is used for measuring gauge pressure, so that the pressure guiding module is provided with a pressure taking channel 310 and an atmospheric channel 250, an inner end of the atmospheric channel 250 is communicated with one of the pressure taking cavities, and an outer end is opened on the surface of the pressure guiding module. The inner end of the pressure taking channel 310 is communicated with the other pressure taking cavity, the pressure leading module is provided with a pressure taking connector 300, the outer end of the pressure taking channel 310 penetrates out of the pressure taking connector 300, and the pressure taking channel 310 is used for introducing external fluid into the corresponding pressure taking cavity.

Specifically, as shown in fig. 3, the pressure guiding module includes a cylindrical pressure guiding base 200, the differential pressure sensor module 100 is disposed above the pressure guiding base 200, two pressure guiding outlets are respectively opened on the upper surface of the pressure guiding base 200, and pressure guiding pipe sockets are respectively disposed at the pressure guiding outlets. The upper surface of the pressure guide base 200 is provided with a mounting groove, the differential pressure sensor module 100 is arranged in the mounting groove, and the two pressure guide pipes 160 of the differential pressure sensor module 100 are respectively inserted into corresponding pressure guide pipe 160 sockets in a sealing manner. The differential pressure sensor module 100 is not in contact with the inner wall of the installation groove and is supported and suspended only by two pressure guiding pipes 160. The design is designed to prevent the differential pressure sensor module 100 from being deformed due to assembly stress without a tight assembly relationship between the differential pressure sensor module 100 and the pressure guide 200, so as to avoid deformation of a sensitive element in the differential pressure sensor module 100, namely the diaphragm 120, due to assembly. The upper part of the pressure guide base 200 is also used for installing a signal processing module and a gauge outfit.

The pressure measuring connector 300 is arranged at the lower end of the pressure guide seat 200, the connecting end of the pressure measuring connector 300 faces downwards, the pressure measuring channel 310 is arranged along the axial direction of the pressure measuring connector 300, and the upper end of the pressure measuring channel 310 is opposite to the pressure measuring cavity communicated with the pressure measuring channel.

When the pressure measuring connector is used, the pressure measuring connector 300 is directly connected with a pressure source to be measured, and the indicator can be conveniently and directly observed.

As shown in fig. 3, the two pressure guiding channels are an atmospheric pressure guiding channel 220 and a measurement pressure guiding channel 210, respectively, wherein a pressure taking cavity corresponding to the atmospheric pressure guiding channel 220 is an atmospheric pressure taking cavity 240, and a pressure taking cavity corresponding to the measurement pressure guiding channel 210 is a measurement pressure taking cavity 260. Two the pressure inlet that draws of pressing the passageway is connected with the horn mouth respectively, two the opening orientation of horn mouth is corresponding get and press the chamber, two it has sealed the covering respectively on the horn mouth keep apart diaphragm 230. The atmospheric pressure channel 220 is used for introducing the ambient air pressure into the atmospheric pressure taking cavity 240, and the measurement pressure introducing channel 210 is used for introducing the fluid to be measured into the measurement pressure taking cavity 260. Thus, the differential pressure sensor module 100 measures gauge pressure.

The pressure guide seat 200 has the following specific structure: the bottom surface of the pressure guide seat 200 is provided with a blind mounting hole, the bottom of the blind mounting hole is provided with one horn mouth, and the horn mouth is communicated with the pressure guide inlet of the atmospheric pressure guide channel 220. And a measurement leading pressing block is fixedly arranged in the mounting blind hole, a first thin layer cavity is sealed and enclosed between the measurement leading pressing block and the bottom of the mounting blind hole, and the first thin layer cavity forms the atmospheric pressure taking cavity 240.

The atmospheric pressure introduction channel 220 comprises two first vertical sections arranged on the pressure introduction seat 200, the two first vertical sections are vertically separated, the upper end of the first vertical section positioned above forms a pressure introduction outlet of the atmospheric pressure introduction channel 220, a first transverse section is connected between the lower end of the first vertical section positioned above and the upper end of the first vertical section positioned below, and the lower end of the first vertical section positioned below forms a pressure introduction inlet of the atmospheric pressure introduction channel 220.

The upper end surface of the measurement pressure guide block is provided with a first expansion groove, the first expansion groove is over against the isolation diaphragm 230 at the pressure guide inlet of the atmospheric pressure guide channel 220, and the first expansion groove is communicated with the atmospheric pressure taking cavity 240 to increase the volume of the atmospheric pressure taking cavity 240, so that atmospheric pressure can be more sensitively acted on the corresponding isolation diaphragm 230.

The atmospheric channel 250 is radially opened on the pressure-inducing seat 200 corresponding to the sidewall of the atmospheric pressure-taking cavity 240.

The lower surface of the measurement pressure guiding block is provided with one horn mouth which is communicated with a pressure guiding inlet of the measurement pressure guiding channel 210, and the measurement pressure guiding channel 210 is arranged on the measurement pressure guiding block and the pressure guiding seat 200. The lower end face of the pressure guiding seat 200 is covered with a lower end cover 301 in a buckling manner, a sealed second thin layer cavity is enclosed between the lower end cover 301 and the lower surface of the measurement pressure guiding block, and the second thin layer cavity forms the measurement pressure measuring cavity 260.

The measurement pressure guiding channel 210 includes a second vertical section located above and arranged on the pressure guiding base 200, and a second vertical section located below and arranged on the measurement pressure guiding block. The upper end of the second vertical section above forms a pressure guiding outlet of the measurement pressure guiding channel 210, and the lower end of the second vertical section below forms a pressure guiding inlet of the measurement pressure guiding channel 210. The measuring and pressurizing block is provided with a communicating cavity 270, and the communicating cavity 270 communicates the lower end of the second vertical section positioned above with the second vertical section positioned below.

To facilitate the formation of the pressure guiding channel and the pressure taking cavity in the pressure guiding seat 200: the installation blind hole is multistage step hole, it draws the briquetting to measure includes cylindric last block 201 and lower block 202, the diameter of lower block 202 is greater than go up block 201 diameter. The upper block body 201 and the upper section of the installation blind hole are positioned through steps and are welded and sealed between the circumferential surfaces, and the lower block body 202 and the lower section of the installation blind hole are also positioned through steps and are welded and sealed between the circumferential surfaces. The lower surface of the upper block body 201 and the upper surface of the lower block body 202 are separated from each other, so that the communication cavity 270 is defined by the upper surface and the inner wall of the mounting blind hole, the second vertical section located below is arranged in the center of the lower block body 202, the upper end of the second vertical section located below is connected with the communication cavity 270, and the lower end of the second vertical section located below is connected with a corresponding horn mouth.

The inner wall of the lower end cover 301 is provided with a second capacity expansion groove, the second capacity expansion groove is over against the isolation diaphragm 230 at the pressure introduction inlet of the measurement pressure introduction channel 210, and the second capacity expansion groove is communicated with the measurement pressure introduction cavity 260 so as to expand the volume of the measurement pressure introduction cavity 260, and the pressure of the external fluid to be measured can be more sensitively applied to the corresponding isolation diaphragm 230.

The lower end cover 301 is in threaded sealing connection with the side wall of the lower end of the pressure guide seat 200. A columnar pressure tapping connector 300 is integrally formed in the center of the lower surface of the lower end cover 301, and a pressure tapping channel 310 penetrates through the centers of the pressure tapping connector 300 and the lower end cover 301. The outer wall of the lower end of the pressure tapping connector 300 is provided with a connecting thread 320 so as to be directly connected with an external pressure source through the thread. The outer wall of the upper end of the pressure tapping connector 300 is in an outer hexagon shape 330, so that the screwing operation is facilitated.

The pressure detection sensor is simple and compact in pressure guiding structure, convenient to connect with an external pressure source during use and easy to use.

In order to improve the measurement accuracy of the capacitive differential pressure sensor and thus the detection accuracy of the pressure detection sensor, the differential pressure sensor module 100 is structurally improved over the conventional capacitive differential pressure sensor.

Referring to fig. 4, two sealed sensing cavities 130 separated by a diaphragm 120 are formed in the differential pressure sensor module 100, and a pressure guiding pipe 160 is connected to each sensing cavity 130. The differential pressure sensor modules 100 are respectively provided with static pressure compensation structures corresponding to the sensing cavities 130 thereof.

The differential pressure sensor module 100 includes two discoid first membrane seats 110, two press from both sides the diaphragm 120 that is equipped with the metal material between the first membrane seat 110, two the first membrane seat 110 edge butt welding connect in order to incite somebody to action the diaphragm 120 is fixed, every first membrane seat 110 with form sealed response chamber 130 between the diaphragm 120, every response chamber 130 is connected with respectively the pressure tube 160.

The static pressure compensation structure is used to restrain the first diaphragm seat 110 from deforming outward under the high pressure of the liquid in the sensing chamber 130. The static pressure compensation structure comprises a second film seat 140 arranged outside each first film seat 110, the second film seats 140 are fixedly connected with the outer side edges of the corresponding first film seats 110 in a sealing manner, a pressure stabilizing cavity 150 is defined between each second film seat 140 and the corresponding first film seat 110, and the pressure stabilizing cavity 150 is communicated with the induction cavity 130 on the same side of the diaphragm 120.

The second diaphragm seat 140 has the same structure as the first diaphragm seat 110. The first membrane seat 110 is provided with a groove on one side facing the membrane 120, and the groove on the second membrane seat 140 faces the corresponding outer side of the first membrane seat 110. The pressure introduction tube 160 connected to each sensing cavity 130 is sealed outward and penetrates through the first and

second film holders

110 and 140 in sequence, and is opened in the corresponding pressure stabilizing cavity 150.

The inner side surface of each first film holder 110 is provided with a film-coated electrode. The plated electrode on the inner side of each first film holder 110 and the corresponding side of the film 120 opposite to the plated electrode form a first capacitor, i.e. a measurement capacitor. The plated electrode of each first film holder 110 is connected to a first signal lead 170, and the first signal leads 170 respectively penetrate through the first film holder 110 in a sealed manner.

The inner side surface of the second film holder 140 is also provided with a plated electrode, and the plated electrode and the outer metal surface of the first film holder 110 form a second capacitor, i.e. a compensation capacitor. The plated electrode on each second film seat 140 is connected to a second signal lead 180, and the second signal lead 180 penetrates through the second film seat 140 in a sealing manner.

In the presence of a pressure difference, the diaphragm 120 deforms to the pressure-less side, thereby causing the capacitance of the two first capacitances to change in magnitude, and the resulting capacitance change signals are conducted from the first signal leads 170 to external signal processing circuits, respectively, for use in calculating the differential pressure. For each first film seat 110, the hydraulic pressure in the pressure stabilizing cavities 150 on the two sides of the first film seat is always consistent with that in the induction cavity 130, so that the outward deformation of the first film seat 110 in a high-pressure state can be inhibited, and the measurement precision is improved. This is to improve the measurement accuracy from a mechanical point of view.

Since the silicon oil is a medium between the two electrode plates of the second capacitor, the dielectric constant changes when the temperature of the silicon oil changes, so that the capacitance of the second capacitor changes. Meanwhile, although the outward deformation of the first diaphragm seat 110 is suppressed, the liquid pressure received by the first diaphragm seat 110 is transmitted to the second diaphragm seat 140 on the same side as the diaphragm 120, so that the second diaphragm seat 140 is slightly deformed outward, and the capacitance of the second capacitor is also changed. The formed capacitance change signals are conducted from the second signal leads 180 to an external signal processing circuit, respectively. The signal can be used for detecting parameters such as the temperature and the static pressure of the silicone oil, and can also be substituted into the calculation of the pressure value to be used for correcting the differential pressure value measured based on the first capacitor, so that the measurement accuracy of the sensor is further improved from the electrical point of view.

The first diaphragm seat 110 includes an inner disc 111 made of glass and an outer disc 112 made of metal, the inner side surface of the inner disc 111 is provided with the groove, the inner disc 111 and the outer disc 112 are fused, and the outer side surface and the edge of the inner disc 111 are covered by the outer disc 112. The edges of the outer disks 112 of the two first diaphragm holders 110 hold the diaphragm 120 and are welded.

The inner disc 111 partially extends outwards beyond the outer circumferential surface of the outer disc 112 to form an extension block 113, and the first signal lead 170 is led out from the inner disc 111 outwards through the extension block 113, so that the first signal lead 170 and the plated electrode are insulated from the outer disc 112. In this structure, the first signal lead 170 is embedded in the inner disk 111 and integrally formed when the first film holder 110 is manufactured, mainly from a process point of view. The mounting structure of the second signal lead 180 on the second film holder 140 is the same as that of the first signal lead 170.

The inner wall of the groove is provided with the film-coated electrode. The connection point of the first signal lead 170 or the second signal lead 180 and the corresponding film-coated electrode is close to the edge of the corresponding groove, so that the processing is convenient.

After the sensor is assembled, all the outer disks 112 made of metal are welded to the diaphragm 120 to form a conductor, all the outer disks 112 and the diaphragm 120 are connected to the same capacitance lead, the capacitance lead and the first signal lead 170 form two leads for measuring capacitance, and the capacitance lead and the second signal lead 180 form two leads for compensating capacitance. All of the first signal lead 170, the second signal lead 180, and the capacitance lead are connected to an external signal processing circuit.

One specific structure of the pressure guiding tube 160 is: the pressure introduction pipe 160 includes a straight pipe 161 and an elbow pipe 162. The straight pipe 161 is inserted into the center of the first diaphragm seat 110, two ends of the straight pipe 161 are respectively opened on the bottom surface of the groove of the inner disc 111 and the outer side surface of the outer disc 112, and the pipe wall of the straight pipe 161 is sealed with the inner disc 111 and the outer disc 112.

The bent pipe 162 penetrates through the center of the second membrane seat 140, the inner end of the bent pipe 162 is opened on the bottom surface of the groove of the second membrane seat 140, the inner end of the bent pipe 162 is opposite to the outer end of the straight pipe 161, the outer end of the bent pipe 162 penetrates out of the second membrane seat 140, and the outer wall of the bent pipe 162 is sealed with the second membrane seat 140.

Finally, it should be noted that the above-mentioned description is only a preferred embodiment of the present invention, and those skilled in the art can make various similar representations without departing from the spirit and scope of the present invention.

Claims

1. The utility model provides a capacitance associated mode pressure detection sensor, is including drawing pressure module and differential pressure sensor module (100), be equipped with in differential pressure sensor module (100) and separate two sealed response chambeies (130) that form by diaphragm (120), every response chamber (130) are connected with respectively and draw and press pipe (160), draw and press to correspond two on the module draw and press pipe (160) and seted up respectively and draw and press the passageway, draw and press the both ends of passageway and be respectively for drawing and press the entry and draw and press the export, wherein two draw and press the export and set up respectively and draw and press the module surface to with corresponding draw and press pipe (160) intercommunication, its characterized in that:

the two pressure leading inlets are opened in the pressure leading module, pressure taking cavities are respectively formed in the pressure leading module corresponding to the two pressure leading inlets, and isolation diaphragms (230) are respectively covered on the two pressure leading inlets in a sealing manner so as to separate the pressure taking cavities from the pressure leading inlets;

the pressure guiding module is provided with a pressure taking channel (310) and an atmospheric channel (250), the atmospheric channel (250) is communicated with one pressure taking cavity, and the inner end of the pressure taking channel (310) is communicated with the other pressure taking cavity;

the pressure tapping module is provided with a pressure tapping joint (300), and the outer end of the pressure tapping channel (310) penetrates out of the pressure tapping joint (300);

the differential pressure sensor module (100) is provided with a static pressure compensation structure corresponding to the sensing cavity (130).

2. A capacitive direct-coupled pressure sensor as claimed in claim 1, wherein: the pressure guiding module comprises a cylindrical pressure guiding seat (200), the differential pressure sensor module (100) is arranged above the pressure guiding seat (200), and two pressure guiding outlets are respectively arranged on the upper surface of the pressure guiding seat (200);

the pressure tapping connector (300) is arranged at the lower end of the pressure tapping seat (200), the connecting end of the pressure tapping connector (300) faces downwards, the pressure tapping channel (310) is arranged along the axial direction of the pressure tapping connector (300), and the upper end of the pressure tapping channel (310) is opposite to the pressure tapping cavity communicated with the pressure tapping channel.

3. A capacitive direct-coupled pressure sensor according to claim 1 or 2, wherein: the differential pressure sensor module (100) comprises two disc-shaped first membrane seats (110), a membrane (120) is clamped between the two first membrane seats (110), the edges of the two first membrane seats (110) are in butt welding connection to fix the membrane (120), a sealed induction cavity (130) is formed between each first membrane seat (110) and the membrane (120), and each induction cavity (130) is connected with a pressure guiding pipe (160);

a second film seat (140) is arranged outside each first film seat (110), the second film seat (140) is fixedly connected with the outer side edge of the corresponding first film seat (110) in a sealing mode, a pressure stabilizing cavity (150) is defined between the second film seat (140) and the corresponding first film seat (110), and the pressure stabilizing cavity (150) is communicated with the induction cavity (130) located on the same side of the diaphragm (120).

4. A capacitive direct-coupled pressure sensor as claimed in claim 3, wherein: the second membrane seat (140) is identical in structure to the first membrane seat (110);

one side of the first membrane seat (110) facing the membrane (120) is provided with a groove, and the groove on the second membrane seat (140) faces the corresponding outer side face of the first membrane seat (110);

the pressure leading pipe (160) connected with each sensing cavity (130) penetrates through the first membrane seat (110) and the second membrane seat (140) in an outward sealing mode and is opened in the corresponding pressure stabilizing cavity (150).

5. The capacitive direct-coupled pressure sensor according to claim 4, wherein: the first membrane seat (110) comprises an inner disc (111) made of glass and an outer disc (112) made of metal, the inner side surface of the inner disc (111) is provided with the groove, the inner disc (111) and the outer disc (112) are fused, and the outer side surface and the edge of the inner disc (111) are covered by the outer disc (112);

the diaphragm (120) is made of metal, and the edges of the outer disks (112) of the two first diaphragm bases (110) clamp the diaphragm (120) and are connected in a welding mode;

the pressure guiding pipe (160) comprises a straight pipe (161) and a bent pipe (162);

the straight pipe (161) penetrates through the center of the first membrane seat (110), two ends of the straight pipe (161) are respectively opened on the bottom surface of the groove of the inner disc (111) and the outer side surface of the outer disc (112), and the pipe wall of the straight pipe (161) is sealed with the inner disc (111) and the outer disc (112);

the bent pipe (162) penetrates through the center of the second membrane seat (140), the inner end of the bent pipe (162) is opened on the bottom surface of the groove of the second membrane seat (140), the inner end of the bent pipe (162) is opposite to the outer end of the straight pipe (161), the outer end of the bent pipe (162) penetrates out of the second membrane seat (140), and the outer wall of the bent pipe (162) is sealed with the second membrane seat (140);

the bent pipes (162) are hard pipes, and the differential pressure sensor module (100) is supported by the two bent pipes (162) to be suspended above the pressure guide seat (200).

6. The capacitive direct-coupled pressure sensor according to claim 4, wherein: the inner side surface of each first membrane seat (110) is respectively provided with a coated electrode, the coated electrode and the corresponding side surface of the membrane (120) form a measuring capacitor, the coated electrode of each first membrane seat (110) is respectively connected with a first signal lead (170), and the first signal leads (170) respectively penetrate through the first membrane seats (110) in a sealing manner;

the inner side surface of the second film seat (140) is also provided with a plated electrode, the plated electrode is opposite to the corresponding metal surface on the outer side of the first film seat (110) to form a compensation capacitor, the plated electrode on the inner side surface of the second film seat (140) is connected with a second signal lead (180), and the second signal lead (180) penetrates out of the second film seat (140) in a sealing mode.

7. A capacitive direct-coupled pressure sensor as claimed in claim 2, wherein: the two pressure leading channels are respectively an atmospheric pressure leading channel (220) and a measurement pressure leading channel (210), wherein a pressure taking cavity corresponding to the atmospheric pressure leading channel (220) is an atmospheric pressure taking cavity (240), and a pressure taking cavity corresponding to the measurement pressure leading channel (210) is a measurement pressure taking cavity (260);

the pressure-inducing inlets of the two pressure-inducing channels are respectively connected with a bell mouth, the openings of the two bell mouths face to the corresponding pressure-taking cavities, and the two bell mouths are respectively covered with an isolation diaphragm (230) in a sealing way;

the bottom surface of the pressure guide seat (200) is provided with a mounting blind hole, the hole bottom of the mounting blind hole is provided with the horn mouth, and the horn mouth is communicated with a pressure guide inlet of the atmosphere pressure guide channel (220);

and a measurement leading pressing block is fixedly arranged in the mounting blind hole, a first thin layer cavity is sealed and enclosed between the measurement leading pressing block and the bottom of the mounting blind hole, and the first thin layer cavity forms the atmospheric pressure taking cavity (240).

8. A capacitive direct-coupled pressure sensor as claimed in claim 7, wherein: the atmosphere pressure guide channel (220) comprises two first vertical sections arranged on the pressure guide seat (200), the two first vertical sections are vertically separated, the upper end of the first vertical section positioned above forms a pressure guide outlet of the atmosphere pressure guide channel (220), a first transverse section is connected between the lower end of the first vertical section positioned above and the upper end of the first vertical section positioned below, and the lower end of the first vertical section positioned below forms a pressure guide inlet of the atmosphere pressure guide channel (220).

9. A capacitive direct-coupled pressure sensor as claimed in claim 7, wherein: the lower surface of the measurement pressure guiding block is provided with another bell mouth which is communicated with a pressure guiding inlet of the measurement pressure guiding channel (210), and the measurement pressure guiding channel (210) is arranged on the measurement pressure guiding block and the pressure guiding seat (200);

the lower end face of the pressure leading seat (200) is covered with a lower end cover (301) in a buckling mode, a sealed second thin layer cavity is formed between the lower end cover (301) and the lower surface of the measurement pressure leading block in a surrounding mode, and the second thin layer cavity forms the measurement pressure measuring cavity (260).

10. A capacitive direct-coupled pressure sensor as claimed in claim 9, wherein: the measurement pressure leading channel (210) comprises a second vertical section which is arranged on the pressure leading seat (200) and is positioned above, and a second vertical section which is arranged on the measurement pressure leading block and is positioned below;

the upper end of the second vertical section positioned above forms a pressure guiding outlet of the measurement pressure guiding channel (210), and the lower end of the second vertical section positioned below forms a pressure guiding inlet of the measurement pressure guiding channel (210);

the measuring and pressurizing block is provided with a communication cavity (270), and the lower end of the second vertical section positioned above and the second vertical section positioned below are communicated through the communication cavity (270).