CN216746537U - Silicon piezoresistive gas pressure sensor - Google Patents

Abstract

The utility model discloses a silicon piezoresistive gas pressure sensor, which comprises: the shell is provided with a first cavity, a second cavity and a third cavity which are separated from each other, the first cavity is provided with a first air nozzle, the second cavity is provided with a second air nozzle, the shell is also provided with a calibration flow channel and two first air flow channels, the calibration flow channel is communicated with the first cavity and the third cavity, one first air flow channel is communicated with the first cavity and the third cavity, and the other first air flow channel is communicated with the second cavity and the third cavity; the sensing element is accommodated in the first chamber, and a calibration flow channel is sealed at the back side of the silicon piezoresistive gas pressure sensing element; the air duct is arranged in the first cavity, a pipe orifice at one end of the air duct is connected to the first air nozzle, and a pipe orifice at the other end of the air duct extends towards the direction far away from the silicon piezoresistive gas pressure sensitive element; the sealing plug is accommodated in the third chamber; and a driving member for driving the sealing plug. The technical scheme of the utility model aims to reduce dust or oil stain attached to the silicon piezoresistive gas pressure sensitive element.

Description

Silicon piezoresistive gas pressure sensor

Technical Field

The utility model relates to the technical field of sensors, in particular to a silicon piezoresistive gas pressure sensor.

Background

Silicon piezoresistive gas pressure sensors have a wide range of applications in industrial production, such as pipeline pressure, wind speed detection, unmanned aerial vehicle systems, and the like. Because the application environment of the silicon piezoresistive gas pressure sensor is complex, the silicon piezoresistive gas pressure sensitive element is likely to be adhered by dust and oil stains, and the performance of the silicon piezoresistive gas pressure sensor is affected.

SUMMERY OF THE UTILITY MODEL

The utility model mainly aims to provide a silicon piezoresistive gas pressure sensor, aiming at reducing dust or oil stains attached to a silicon piezoresistive gas pressure sensitive element.

In order to achieve the above object, the present invention provides a silicon piezoresistive gas pressure sensor comprising:

the shell is provided with a first cavity, a second cavity and a third cavity which are separated from each other, the first cavity is provided with a first air nozzle, the second cavity is provided with a second air nozzle, the shell is also provided with a calibration flow channel and two first air flow channels, the calibration flow channel is communicated with the first cavity and the third cavity, one first air flow channel is communicated with the first cavity and the third cavity, and the other first air flow channel is communicated with the second cavity and the third cavity;

the silicon piezoresistive gas pressure sensing element is accommodated in the first cavity, and the back side of the silicon piezoresistive gas pressure sensing element seals the calibration flow channel;

the air guide pipe is arranged in the first cavity, a pipe orifice at one end of the air guide pipe is connected to the first air nozzle, and a pipe orifice at the other end of the air guide pipe extends towards the direction far away from the silicon piezoresistive gas pressure sensitive element;

a sealing plug housed within the third chamber; and

and the driving piece drives the sealing plug to open and close the first airflow channel.

Optionally, the first airflow channel has a first airflow port communicated with the first chamber, and a pipe orifice at the other end of the air duct faces the first airflow port.

Optionally, a tube orifice at the other end of the air duct extends into the first airflow channel, and the radius of the air duct is smaller than that of the first airflow channel.

Optionally, two mounting lugs extend outwardly from the bottom of the housing.

Optionally, the mounting lugs are provided with threaded holes.

Optionally, the silicon piezoresistive gas pressure sensor further comprises two gas pipes, the two gas pipes are located outside the housing, the first gas nozzle is communicated with one gas pipe, and the second gas nozzle is communicated with the other gas pipe.

Optionally, the silicon piezoresistive gas pressure sensor further comprises two gas pipes, the two gas pipes are located outside the housing, the first gas nozzle is communicated with one gas pipe, and the second gas nozzle is communicated with the other gas pipe.

Optionally, the inner wall of the air pipe is laid with adsorption paper, and the adsorption paper is used for adsorbing dust or oil smoke.

Optionally, the adsorption paper is detachably connected with the air pipe.

In the technical scheme of the utility model, the gas entering from the first gas nozzle may have dust or oil stains, the gas entering from the first gas nozzle flows towards the direction far away from the silicon piezoresistive gas pressure sensitive element under the guiding action of the gas guide pipe, most of the dust or oil stains in the gas can be attached to other places in the first cavity, and thus the dust or oil stains reaching the silicon piezoresistive gas pressure sensitive element can be greatly reduced, so that the silicon piezoresistive gas pressure sensitive element is ensured to have higher performance, and the silicon piezoresistive gas pressure sensor has longer service life.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a cross-sectional view of one embodiment of a MEMS silicon piezoresistive gas pressure sensor according to the utility model;

FIG. 2 is an enlarged view of a portion of FIG. 1 at A;

FIG. 3 is a schematic view of the silicon piezoresistive gas pressure sensor of FIG. 1;

FIG. 4 is a cross-sectional view of the hand grip of FIG. 3;

FIG. 5 is a cross-sectional view of the air tube and the absorbent paper of FIG. 3;

FIG. 6 is a cross-sectional view of yet another embodiment of a silicon piezoresistive gas pressure sensor in accordance with the utility model;

fig. 7 is a structural view of the mounting lug of fig. 6.

The reference numbers illustrate:

the implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, and the like in a specific posture, and if the specific posture is changed, the directional indicator is changed accordingly.

In the present invention, unless otherwise expressly stated or limited, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" appearing throughout includes three juxtapositions, exemplified by "A and/or B" including either A or B or both A and B. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

Referring to fig. 1 to 5, in an embodiment of the present invention, the silicon piezoresistive gas pressure sensor includes:

a housing 100 having a first chamber 111, a second chamber 112 and a third chamber 131 separated from each other, the first chamber 111 having a first air nozzle, the second chamber 112 having a second air nozzle 113, the housing 100 further having a calibration flow channel 140 and two first air flow channels 150, the calibration flow channel 140 communicating the first chamber 111 and the third chamber 131, one of the first air flow channels 150 communicating the first chamber 111 and the third chamber 131, the other first air flow channel 150 communicating the second chamber 112 and the third chamber 131;

a silicon piezoresistive gas pressure sensing element 121 which is accommodated in the first chamber 111, and a back side of the silicon piezoresistive gas pressure sensing element 121 seals the calibration flow channel 140;

a sealing plug 300 housed in the third chamber 131; and

the driving member 400 drives the sealing plug 300 to open and close the first air flow passage 150.

The operation of the silicon piezoresistive gas pressure sensor is explained as follows:

s1: the silicon piezoresistive gas pressure sensor is in a non-working state;

s2: the sealing plug 300 is driven to close the first airflow channel 150 communicated with the second chamber 112 and open the first airflow channel 150 connected with the first chamber 111, and at this time, the front pressure and the back pressure of the silicon piezoresistive gas pressure sensing element 121 are the same;

s4: zero point correction is carried out, and the silicon piezoresistive gas pressure sensor memorizes the zero point parameter at the temperature moment;

s5: the sealing plug 300 is driven to close the first air flow channel 150 communicated with the first cavity 111 and open the first air flow channel 150 communicated with the second cavity 112, and at the moment, the front pressure and the back pressure of the silicon piezoresistive gas pressure sensing element 121 are different;

s6: and the silicon piezoresistive gas pressure sensor is enabled to be in a working state, and the pressure sensor starts to test the output signal of the silicon piezoresistive gas pressure sensor under the pressure action at the temperature moment based on the sensing zero point parameter of the temperature moment memorized by the previous calibration zero point work. Because the temperature during calibration and the temperature during pressure test have small changes and can be ignored.

Specifically, in one embodiment, the housing 100 includes an upper housing 110, a circuit board 120 and a lower housing 130 assembled in this order from the top, wherein, the upper housing 110 has a first chamber 111 and a second chamber 112, the first chamber 111 and the second chamber 112 are open downwards, the lower housing 130 has a third chamber 131 open upwards, the upper side of the circuit board 120 seals the openings of the first chamber 111 and the second chamber 112 hermetically, the lower side seals the opening of the third chamber 131, the circuit board 120 is provided with three holes, one of the holes is directly communicated with the third chamber 131, the channel formed by the hole is the calibration flow channel 140, the lower housing 130 is formed with two air cavities located at both sides of the third chamber 131, the air cavities are communicated with the third chamber 131, one of the two holes of the three holes of the circuit board 120 is communicated with the first chamber 111 and one air cavity to form a first air flow channel 150, and the other is communicated with the second chamber 112 and the other air cavity to form another first air flow channel 150. However, the design is not limited thereto, and in other embodiments, the silicon piezoresistive gas pressure sensor may have other structures.

Optionally, in an embodiment, the sealing plug 300 includes two sealing pillars 310, one sealing pillar 310 is movably disposed on one first airflow channel 150, and an outer peripheral surface of the sealing pillar 310 is configured to be in sealing fit with an inner peripheral surface of the first airflow channel 150.

It can be appreciated that if one of the airflow channels is less air-tight with the third chamber 131, the calibration zero point operation and the pressure test operation are easily affected.

At present, the first air flow channel 150 of the silicon piezoresistive gas pressure sensor on the market has the second air flow port 152 communicated with the third chamber 131, the surface of the second air flow port 152 is used for surface-to-surface matching with the end surface of the sealing plug 300, however, once particulate matter exists on the surface of the second air flow port 152, a gap is formed between the surface of the second air flow port 152 and the end surface of the sealing plug 300 in the matching process, so the sealing plug 300 cannot seal the first air flow channel 150 well, in the present scheme, the problem can be solved perfectly by sealing and matching the outer circumferential surface of the sealing convex column 310 with the inner circumferential surface of the first air flow channel 150, if the outer circumferential surface of the sealing convex column 310 is adhered with the particulate matter, the particulate matter is blocked by the surface of the second air flow port 152 in the process of moving towards the second air flow port 152, and the particulate matter cannot enter the first air flow channel 150 along with the sealing convex column 310, the outer circumferential surface of the sealing convex column 310 can be in good sealing fit with the inner circumferential surface of the first airflow channel 150; if the inner circumferential surface of the first airflow channel 150 is adhered with particles, the sealing protrusion 310 pushes the particles to move during the process that the sealing protrusion 310 enters the first airflow channel 150, so that the particles are far away from the position where the first airflow channel 150 is matched with the sealing protrusion 310, and thus, the outer circumferential surface of the sealing protrusion 310 can be better matched with the inner circumferential surface of the first airflow channel 150 in a sealing manner. Therefore, the data measured by the silicon piezoresistive gas pressure sensor is closer to the real data.

It should be noted that, in an embodiment, the first airflow channel 150 has a communication section 153 extending along the horizontal direction, the communication section 153 is used for communicating with the third chamber 131, wherein the sealing protrusion 310 is used for being in sealing fit with the communication section 153.

Optionally, in an embodiment, the sealing convex pillar 310 is provided with a second gas flow channel 311 communicated with the first gas flow channel 150, one opening of the second airflow channel 311 is located on the end surface of the sealing convex column 310, the other opening of the second airflow channel 311 is located on the outer circumferential surface of the sealing convex column 310, in this manner, whether in the state of opening the first airflow passage 150 or in the state of closing the first airflow passage 150, the sealing convex column 310 has a part extending into the first airflow channel 150 all the time, so as to avoid the situation that the sealing convex column 310 cannot extend into the first airflow channel 150 again due to the deviation of the external reason after the sealing convex column 310 is separated from the first airflow channel 150, in the state of opening the first airflow channel 150, the opening on the outer circumferential surface of the sealing protrusion 310 is only required to be communicated with the third chamber 131, and the first end is not required to be separated from the first airflow channel 150. However, the design is not limited thereto, and in other embodiments, the sealing convex pillar 310 may not be provided with the second airflow channel 311, as long as the sealing convex pillar 310 can be ensured to extend into the first airflow channel 150 all the time.

Optionally, in an embodiment, a radius of the second airflow channel 311 is in a range from 3mm to 4mm, when the radius of the second airflow channel 311 is smaller, the second airflow channel 311 is easily blocked by particles, which affects a gas flow between the third chamber 131 and the first airflow channel 150, when the radius of the second airflow channel 311 is larger, the sealing convex pillar 310 is easily enlarged, and when the sealing convex pillar 310 is enlarged, an area of an outer circumferential surface of the sealing convex pillar 310 is enlarged, which means that an area needing sealing fit is enlarged, and a sealing difficulty is improved. Therefore, when the radius of the second airflow channel 311 is in the range of 3mm to 4mm, the second airflow channel 311 is not easily blocked by particles, and the difficulty of sealing the first airflow channel 150 by the sealing convex column 310 is also reduced.

Optionally, in an embodiment, the sealing protrusion 310 has a first end close to the first airflow channel 150, and a peripheral edge of the first end is provided with a chamfer, and when the sealing protrusion 310 is displaced, the sealing protrusion 310 can slide into the first airflow channel 150 under the guiding action of the chamfer. However, the design is not limited thereto, and in other embodiments, the sealing convex pillar 310 may not be provided with a chamfer, as long as the sealing convex pillar 310 can be ensured to extend into the first airflow channel 150 all the time.

Optionally, in an embodiment, the angle of the chamfer ranges from 30 degrees to 60 degrees, and the chamfer is not easy to slide into the first airflow channel 150 even if the angle is smaller or larger, and when the angle ranges from 30 degrees to 60 degrees, the sealing pillar 310 can slide into the first airflow channel 150 more smoothly.

Alternatively, in an embodiment, the sealing plug 300 includes a plug body 320 in an elongated shape, two sealing convex pillars 310 are respectively disposed at two opposite ends of the plug body 320, the driving member 400 is configured as an electromagnetic coil 410, the plug body 320 is disposed through the electromagnetic coil 410, and the sealing plug 300 is located between the two first airflow passages 150, it can be understood that the electromagnetic coil 410 drives the sealing plug 300 to reciprocate between the two first airflow passages 150. However, the design is not limited thereto, and in other embodiments, the sealing plug 300 and the driving member 400 have other forms as long as the sealing plug can be driven to open and close the first airflow channel 150.

Optionally, in an embodiment, the bottom of the housing 100 extends outward to form the mounting lug 500, and the surrounding environment of the extended mounting lug 500 is relatively open, so that it is convenient for a person or a tool to connect the mounting lug 500 to other structures, and it is convenient for the silicon piezoresistive gas pressure sensor to be mounted.

Alternatively, in one embodiment, there are two mounting lugs 500, and the more mounting lugs 500, the more firmly the silicon piezoresistive gas pressure sensor is mounted.

Alternatively, in one embodiment, two mounting lugs 500 are disposed on two sides of the housing 100, so that the silicon piezoresistive gas pressure sensor is more firmly connected to other structures.

Optionally, referring to fig. 6 and 7 together, in an embodiment, the silicon piezoresistive gas pressure sensor further includes a magnet 600 mounted on the mounting lug 500, and the silicon piezoresistive gas pressure sensor is connected to other structures by a magnetic attraction manner, so that the silicon piezoresistive gas pressure sensor is very convenient and fast to mount without tools, and can be connected to each other as long as the silicon piezoresistive gas pressure sensor is close to the structure capable of being attracted by the magnet 600.

Optionally, in an embodiment, the mounting lug 500 includes a lug body 520 protruding from the bottom of the casing 100, the lug body 520 is provided with a receiving cavity 521, and the magnet 600 is disposed in the receiving cavity 521, so that the magnet 600 is prevented from colliding with an external object, the structure of the magnet 600 is complete, and the normal use of the magnet 600 is ensured. However, the design is not limited thereto, and in other embodiments, the magnet 600 may be directly disposed on the lower surface of the mounting lug 500 to be exposed.

Optionally, in an embodiment, the opening of the accommodating cavity 521 is located at the bottom of the lug body 520, the bottom of the lug body 520 is provided with a sliding groove 530 communicating with the accommodating cavity 521, the mounting lug 500 further includes a sliding plate 530 sliding in the sliding groove 530, and the sliding plate 530 can seal the opening of the accommodating cavity 521, so that the magnet 600 is prevented from colliding with an external object, the structure of the magnet 600 is complete, and the normal use of the magnet 600 is ensured. However, the design is not limited thereto, in other embodiments, the bottom of the lug body 520 is provided with a mounting ring groove surrounding the opening of the receiving cavity, the mounting ring groove is communicated with the receiving cavity 521, the mounting lug 500 further comprises a cover plate covering the mounting ring groove, and the cover plate can seal the opening of the receiving cavity.

Optionally, in an embodiment, the thickness of the sliding plate 530 ranges from 2mm to 3mm, when the thickness of the sliding plate 530 is too small, the sliding plate 530 has a low strength and is easily damaged by external force, and when the thickness of the sliding plate 530 is too large, the magnetic force between the magnet 600 and other structures is weakened, so that the silicon piezoresistive gas pressure sensor is not firmly connected with other structures, and thus, when the thickness of the sliding plate 530 ranges from 2mm to 3mm, the sliding plate 530 has a high structural strength and ensures that the silicon piezoresistive gas pressure sensor is firmly connected with other structures.

Optionally, in one embodiment, the mounting lug 500 is provided with a threaded hole 510, and a screw is inserted through the threaded hole 510 to connect the silicon piezoresistive gas pressure sensor with other structures. However, the design is not limited thereto, and in other embodiments, the magnet 600 is disposed in the installation lug 500, and the silicon piezoresistive gas pressure sensor is connected to other structures by a magnetic attraction manner.

Optionally, in an embodiment, the silicon piezoresistive gas pressure sensor further comprises a wireless communication module 122 housed in the first chamber 111, so that a user can receive information detected by the silicon piezoresistive gas pressure sensor through an electronic device. However, the present disclosure is not limited thereto, and in other embodiments, the wireless communication module 122 may be accommodated in the second chamber 112. It should be noted that the specific structure of the wireless communication module 122 is referred to in the prior art.

Optionally, in an embodiment, the silicon piezoresistive gas pressure sensor airway 700 further includes an airway tube 700, the airway tube 700 is disposed in the first chamber 111, a tube port at one end of the airway tube 700 is connected to the first gas nozzle, and a tube port at the other end of the airway tube 700 extends in a direction away from the silicon piezoresistive gas pressure sensing element 121. The gas entering from the first gas nozzle may have dust or oil contamination, the gas entering from the first gas nozzle flows in a direction away from the silicon piezoresistive gas pressure sensing element 121 under the guiding action of the gas guide tube 700, most of the dust or oil contamination in the gas can be attached to other places in the first chamber 111, and thus the dust or oil contamination reaching the silicon piezoresistive gas pressure sensing element 121 is greatly reduced, and the silicon piezoresistive gas pressure sensing element 121 is ensured to have higher performance, and the silicon piezoresistive gas pressure sensor has longer service life.

Optionally, in an embodiment, the first airflow channel 150 has a first airflow port 151 communicated with the first chamber 111, and an opening at the other end of the air guiding tube 700 faces the first airflow port 151, so that most of the air with dust or oil contamination can flow into the first airflow channel 150 from the first airflow port 151, thereby reducing circulation of the air in the first chamber 111, and further reducing dust or oil contamination attached to the silicon piezoresistive gas pressure sensitive element 121, it can be understood that the dust or oil contamination can be attached to a wall surface of the first airflow channel 150, and when more dust or oil contamination is attached to the wall surface of the first airflow channel 150, the silicon piezoresistive gas pressure sensor can be detached for cleaning, and the difficulty in cleaning the first airflow channel 150 is much less than the difficulty in cleaning the silicon piezoresistive gas pressure sensitive element 121.

Optionally, in an embodiment, a tube opening at the other end of the air duct 700 extends into the first airflow channel 150, and the radius of the air duct 700 is smaller than the radius of the first airflow channel 150, so that the skill can send more dust or greasy dirt-laden air into the first airflow channel 150, and can ensure that the first chamber 111 is always in a communicated state with the first airflow channel 150, thereby ensuring the normal operation of the silicon piezoresistive gas pressure sensor, and the dust and greasy dirt will fall down along the first airflow channel 150 under the action of gravity, and will hardly return to the first chamber 111, further reducing the dust or greasy dirt attached to the silicon piezoresistive gas pressure sensitive element 121.

Optionally, in an embodiment, the silicon piezoresistive gas pressure sensor further includes two gas pipes 810, the two gas pipes 810 are located outside the housing 100, the first gas nozzle is communicated with one gas pipe 810, the second gas nozzle 113 is communicated with the other gas pipe 810, the gas pipe 810 is beneficial to extending a gas measuring range of the silicon piezoresistive gas pressure sensor, after the silicon piezoresistive gas pressure sensor is installed and fixed, the gas pressures of a plurality of points can be detected by moving the gas pipes 810, which is very convenient, and it can be understood that the gas pipes 810 are configured as hoses.

Optionally, in an embodiment, the silicon piezoresistive gas pressure sensor further includes two grippers 900, one gripper 900 is installed corresponding to one gas pipe 810, the gripper 900 is used for connecting a filter screen, and the gas pipe 810 is stably connected with the filter screen through the gripper 900, so that the connection stability between the gas pipe 810 and the filter screen is greatly improved.

Optionally, in an embodiment, the gripper 900 includes the installation ringwall 910 and encircles the direction ringwall 920 of installation ringwall 910, the one end of direction ringwall 920 is joint ringmouth 921, and the opposite other end is connection ringmouth 922, joint ringmouth 921 with the coaxial setting of connection ringmouth 922, the radius of joint ringmouth 921 is greater than the radius of connection ringmouth 922, installation ringwall 910 certainly connect ringmouth 922 towards joint ringmouth 921 extends, installation ringwall 910 has first axis, installation ringwall 910 is used for supplying trachea 810 certainly joint ringmouth 921 court connect ringmouth 922 wears to establish. When the gripper 900 is used, the connecting ring opening 922 is stretched into meshes of a filter screen, the meshes extrude the guide ring wall 920, so that the guide ring wall 920 is contracted, after the clamping ring opening 921 passes through the meshes, the guide ring wall 920 is restored, it can be understood that the inner diameter of the clamping ring opening 921 is larger than that of the meshes, one end of the air pipe 810 is connected with the shell 100, the other opposite end of the air pipe is connected with the gripper 900, the shell 100 and the gripper 900 are respectively positioned on two sides of the filter screen, and under the condition that the guide ring wall 920 is not extruded, one end of the air pipe 810 connected with the gripper 900 is the other side which cannot reach the filter screen, so that the connection stability of the air pipe 810 and the filter screen is improved. However, the design is not limited thereto, and in other embodiments, the handle 900 may be configured in a hook form, one end of the hook is connected to the air tube 810, and the other end is hooked on the mesh of the filter screen.

Optionally, in an embodiment, the inner circumferential surface of the mounting ring wall 910 is provided with a protrusion 911, the protrusion 911 extends from the snap ring opening 921 to the direction of the connecting ring opening 922, the protrusion 911 abuts against the air tube 810, so that the protrusion 911 can prevent the air tube 810 from exiting the mounting ring wall 910, and when the air tube 810 is about to exit the mounting ring wall 910, the protrusion 911 can penetrate into the air tube 810 to prevent the air tube 810 from exiting the mounting ring wall 910. However, the design is not limited thereto, and in other embodiments, the mounting ring wall 910 may have other forms as long as the air tube 810 is prevented from easily separating from the mounting ring wall 910.

Optionally, in an embodiment, the plurality of the protrusions 911 are provided, and the plurality of the protrusions 911 are spaced around the first axis, so as to further increase the difficulty of the air tube 810 exiting the installation annular wall 910.

Optionally, in an embodiment, the inner wall of the air tube 810 is laid with an absorption paper 820, and the absorption paper 820 is used for absorbing dust or oil smoke, so that dust or oil dirt is absorbed on the absorption paper 820 when the gas with dust or oil dirt flows through the duct, and the dust and oil dirt is greatly reduced from entering the housing 100.

Optionally, in an embodiment, the adsorption paper 820 is detachably connected to the air tube 810, so that when a large amount of dust or oil is adsorbed on the adsorption paper 820, a user can replace only the adsorption paper 820 without replacing the air tube 810, thereby saving cost. Of course, in other embodiments the absorbent paper 820 is adhered to the air tube 810.

Optionally, in an embodiment, the absorption paper 820 has a protrusion 821 protruding from the air tube 810 away from the nozzle of the housing 100, so that a user can easily grip the protrusion 821 to take out the whole absorption paper 820 from the air tube 810, which is very convenient.

Optionally, in an embodiment, the protrusion 821 covers the circumference of the mouth of the air pipe 810 away from the housing 100, so as to prevent the protrusion 821 from being shrunk in some cases, thereby preventing the air flow of the air pipe 810 from being affected.

Optionally, in an embodiment, the adsorption paper 820 detachably covers the periphery of the air tube 810 away from the nozzle of the housing 100, so that a user can easily take out the adsorption paper 820 from the air tube 810 and then install a new adsorption paper 820 on the air tube 810.

Optionally, the upper housing 110 has a first mounting surface, the lower housing 130 has a second mounting surface assembled with the first mounting surface, a mounting gap 160 is formed between the first mounting surface and the second mounting surface, and the mounting gap 160 at least communicates with the first cavity 111, the second cavity 112 or the third cavity 131; the silicon piezoresistive gas pressure sensor further comprises a gasket seal 210, and the gasket seal 210 is disposed in the mounting gap 160. The sealing gasket 210 is squeezed by the first mounting surface and the second mounting surface, so that the sealing gasket 210 is elastically deformed to fill the mounting gap 160, and further gas exchange between the outside of the housing 100 and the first chamber 111, the second chamber 112 or the third chamber 131 is avoided, and further the gas tightness of the silicon piezoresistive gas pressure sensor is improved.

Optionally, in an embodiment, the sealing gasket 210 is configured as a rubber gasket, and the rubber gasket has good deformation capability, which is beneficial to further improve the air tightness of the silicon piezoresistive gas pressure sensor. However, the design is not limited thereto, and in other embodiments, the sealing gasket 210 may be configured as other gaskets as long as it has a good first deformability.

Optionally, in an embodiment, the silicon piezoresistive gas pressure sensor with good gas tightness further includes a fastening bolt 220, the fastening bolt 220 is inserted into the first mounting surface and the second mounting surface, and the distance between the first mounting surface and the second mounting surface is adjusted by the fastening bolt 220 so that the sealing gasket 210 can better fill the mounting gap 160, thereby further improving the gas tightness of the silicon piezoresistive gas pressure sensor.

Optionally, in an embodiment, the housing 100 is further provided with an access opening 171, and the access opening 171 is communicated with the first chamber 111; the front surface of the silicon piezoresistive gas pressure sensing element 121 is arranged opposite to the access opening 171; the silicon piezoresistive gas pressure sensor further comprises an access door 172, and the access door 172 is mounted to the access opening 171. The maintenance personnel can open the access door 172, because the access opening 171 is opposite to the silicon piezoresistive gas pressure sensing element 121, the maintenance personnel can directly see the condition of the silicon piezoresistive gas pressure sensing element 121, and the maintenance personnel can select a corresponding tool to extend into the access opening 171 to overhaul the silicon piezoresistive gas pressure sensing element 121 according to the condition of the silicon piezoresistive gas pressure sensing element 121, so that the maintenance personnel is very convenient.

Optionally, in an embodiment, the access door 172 is configured as a plunger, and a periphery of the plunger is in sealing fit with an inner wall surface of the access opening 171, so as to prevent external air from exchanging with air in the first chamber 111 to affect the air tightness of the housing 100.

Alternatively, in an embodiment, the radius of the access opening 171 has a value ranging from 4mm to 6mm, when the radius of the access opening 171 has an excessively small value, it is inconvenient for a maintenance person to observe the silicon piezoresistive gas pressure sensing element 121, and it is also inconvenient for a tool of the maintenance person to extend into the access opening 171 to maintain the silicon piezoresistive gas pressure sensing element 121, and when the radius of the access opening 171 has an excessively large value, a large amount of dust is easily introduced into the first chamber 111 from the access opening 171 by opening the access door 172. Therefore, when the radius of the access opening 171 is in the range of 4mm-6mm, the silicon piezoresistive gas pressure sensing element 121 can be conveniently inspected, and a large amount of dust can be prevented from entering the first chamber 111.

Optionally, in an embodiment, there are two access ports 171, two access doors 172, one access door 172 is disposed corresponding to one access port 171, and the two access ports 171 can facilitate observation and maintenance of the silicon piezoresistive gas pressure sensing device 121 from different angles.

The above description is only an alternative embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications and equivalents of the technical solutions of the present invention that are made by using the contents of the specification and the drawings or directly/indirectly applied to other related technical fields are included in the scope of the present invention.

Claims (6)

1. A silicon piezoresistive gas pressure sensor, comprising:

the shell is provided with a first cavity, a second cavity and a third cavity which are separated from each other, the first cavity is provided with a first air nozzle, the second cavity is provided with a second air nozzle, the shell is also provided with a calibration flow channel and two first air flow channels, the calibration flow channel is communicated with the first cavity and the third cavity, one first air flow channel is communicated with the first cavity and the third cavity, and the other first air flow channel is communicated with the second cavity and the third cavity;

the silicon piezoresistive gas pressure sensing element is accommodated in the first cavity, and the back side of the silicon piezoresistive gas pressure sensing element seals the calibration flow channel;

the air guide pipe is arranged in the first cavity, a pipe orifice at one end of the air guide pipe is connected to the first air nozzle, and a pipe orifice at the other end of the air guide pipe extends towards the direction far away from the silicon piezoresistive gas pressure sensitive element;

a sealing plug housed in the third chamber; and

and the driving piece drives the sealing plug to open and close the first airflow channel.

2. The silicon piezoresistive gas pressure sensor according to claim 1, wherein said first gas flow channel has a first gas flow port communicating with said first chamber, and the other end of said gas-guiding tube has a tube orifice facing said first gas flow port.

3. The silicon piezoresistive gas pressure sensor according to claim 1, wherein a nozzle at the other end of the gas-guiding tube extends into the first gas flow channel, and the radius of the gas-guiding tube is smaller than that of the first gas flow channel.

4. The silicon piezoresistive gas pressure sensor according to claim 1, further comprising two gas tubes, said two gas tubes being located outside said housing, said first gas nozzle being in communication with one of said gas tubes, said second gas nozzle being in communication with the other of said gas tubes.

5. The silicon piezoresistive gas pressure sensor according to claim 4, wherein the inner wall of said air tube is laid with an adsorption paper for adsorbing dust or soot.

6. The silicon piezoresistive gas pressure sensor according to claim 5, wherein said absorbent paper is removably attached to said gas tube.

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