Capacitive pressure sensor

Abstract

The utility model belongs to the technical field of sensors, and particularly relates to a capacitive pressure sensor which comprises a lower base body and an upper base body. According to the capacitive pressure sensor, the stainless steel metal sheaths are driven to be tightly attached to the upper base body and the lower base body through mutual cooperation of the connecting pieces and the stainless steel metal sheaths, so that a completely-closed space is formed between the upper base body and the lower base body, and when the upper surfaces and the lower surfaces of the two stainless steel metal sheaths are subjected to external pressure, the stainless steel metal sheaths are tightly attached to the upper base body and the lower base body. When the pressure is applied to the upper substrate and the lower substrate, the applied force is transmitted to the upper substrate and the lower substrate at the same time, the upper substrate and the lower substrate deform at the moment, and the distance d between the upper electrode on the lower surface of the upper substrate and the lower electrode on the upper surface of the lower substrate changes along with the change of the pressure and also meets the fixed function relation P = f (C). As the upper base body and the lower base body are completely sealed by the connecting piece and the stainless steel metal sheath, the pressure capacitance in the stainless steel metal sheath cannot be influenced by a medium when the pressure sensor is in contact with the measured medium, so that the measurement precision, reliability and environment resistance can be greatly improved, and the service life can be greatly prolonged.

Description

Technical Field

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

[0002] A sensor is a detection device that can sense the information being measured and convert the sensed information into electrical signals or other required forms of information output according to certain rules to meet the requirements of information transmission, processing, storage, display, recording and control.

[0003] When a conventional capacitive pressure sensor contacts the measured medium, the medium between the upper and lower electrodes (5) is prone to change, so that the dielectric constant ε will change, resulting in a deviation between the P=f(C) function and the design, causing measurement errors or even sensor failure. Utility Model Content

[0004] The purpose of the utility model is to provide a capacitive pressure sensor to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a capacitive pressure sensor, comprising a lower substrate and an upper substrate, between which is fixedly installed an isolation sintered body symmetrically distributed and used to support the two, an upper electrode is fixedly installed on the lower surface of the upper substrate located between the relative surfaces of the two isolation sintered bodies, and a lower electrode is fixedly installed on the upper surface of the lower substrate located between the relative surfaces of the two isolation sintered bodies, and the outer surfaces of the upper substrate and the lower substrate are tightly fitted with symmetrically distributed stainless steel metal sheaths through connecting pieces.

[0006] Preferably, the connecting member comprises a baffle, a soft card block and a card slot, the card slot is provided on the front and rear surfaces of the stainless steel metal sheath, and the longitudinal section of the card slot is T-shaped.

[0007] Preferably, the soft card block is slidably inserted into the inner wall of the card slot, the baffle is fixedly installed on the outer surface of the soft card block, and track grooves are provided on both sides of the inner wall of the card slot.

[0008] Preferably, both side surfaces of the soft block are provided with symmetrically distributed rotation grooves, and the inner walls of the rotation grooves are rotatably sleeved with rotation balls.

[0009] Preferably, the outer surface of the rotating ball is rollingly connected to the inner wall of the track groove.

[0010] Compared with the prior art, the beneficial effects of the utility model are as follows: the capacitive pressure sensor, based on the traditional capacitive pressure sensor, utilizes the mutual cooperation of the connecting piece and the stainless steel metal sheath to drive the inner surface of the stainless steel metal sheath to fit closely with the upper substrate and the lower substrate, so that a completely enclosed space is formed between the upper substrate and the lower substrate. When the upper and lower surfaces of the two stainless steel metal sheaths are subjected to external pressure, the force they are subjected to is simultaneously transmitted to the upper substrate and the lower substrate. At this time, the upper substrate and the lower substrate are deformed, and the distance d between the upper electrode located on the lower surface of the upper substrate and the lower electrode located on the upper surface of the lower substrate changes with the pressure, and also satisfies the fixed function relationship of P=f(C). Since the connecting piece and the stainless steel metal sheath completely seal the upper substrate and the lower substrate, when in contact with the measured medium, the medium cannot affect the pressure capacitance inside the stainless steel metal sheath, so the measurement accuracy, high reliability, environmental resistance and service life can be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the structure of the utility model;

[0012] Figure 2 A three-dimensional diagram of the upper substrate structure of a capacitive pressure sensor proposed by the utility model;

[0013] Figure 3 A capacitive pressure sensor proposed by the utility model Figure 2 A magnified view of the structure at center;

[0014] Figure 4 A three-dimensional diagram of a soft card block structure of a capacitive pressure sensor proposed by the utility model;

[0015] Figure 5 This is a three-dimensional diagram of the rotating slot structure of a capacitive pressure sensor proposed by the utility model.

[0016] In the figure: 1, lower substrate; 2, upper substrate; 3, isolation sintered body; 4, upper electrode; 5, lower electrode; 6, stainless steel metal sheath; 7, baffle; 71, soft card block; 72, card slot; 73, rotating slot; 74, rotating ball; 75, track slide slot. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] See also Figure 1-Figure 5The utility model provides a technical solution: a capacitive pressure sensor, comprising a lower substrate 1 and an upper substrate 2, between which an isolation sintered body 3 symmetrically distributed and used to support the two is fixedly installed. The main purpose of designing the isolation sintered body 3 here is to isolate the measuring element of the sensor (such as the upper electrode 4 and the lower electrode 5) and the external environment, thereby protecting the measuring element from the influence of the external medium and ensuring the stability and reliability of the sensor, which has the following advantages:

[0019] 1. Isolation protection: The isolation sintered body 3 isolates the measuring element from the external environment, preventing the external medium such as liquid or gas from directly contacting the measuring element, thereby avoiding the influence of corrosion, contamination or damage of the external medium on the measurement accuracy of the sensor;

[0020] 2. Pressure transmission: The isolation sintered body 3 has certain elasticity and pressure resistance, and can transmit the pressure of the external medium to the measuring element, so that the sensor can accurately sense the pressure changes of the external environment;

[0021] 3. Thermal isolation: In the present application, the isolation sintered body 3 is made of refractory materials, and commonly used refractory materials include refractory bricks, refractory cements, refractory ceramics and refractory fibers, etc., so that it has good high temperature resistance and chemical stability, and can withstand thermal expansion and thermal shock in high temperature environments. In some cases, the isolation sintered body 3 can also play a role in thermal isolation to prevent the high or low temperature of the external environment from affecting the performance of the measuring element;

[0022] 4. Mechanical support: Using the isolation sintered body 3 as the mechanical support structure of the measuring element can ensure that the measuring element is in the correct position and state to provide accurate pressure measurement. The upper substrate 2 is located between the relative surfaces of the two isolation sintered bodies 3 and has an upper electrode 4 fixedly installed on its lower surface. The lower substrate 1 is located between the relative surfaces of the two isolation sintered bodies 3 and has a lower electrode 5 fixedly installed on its upper surface. The outer surfaces of the upper substrate 2 and the lower substrate 1 are tightly fitted with symmetrically distributed stainless steel metal sheaths 6 through connectors. Since the stainless steel metal sheath 6 is completely sealed by the connector, when it comes into contact with the measured medium, the medium cannot affect the pressure capacitance inside the stainless steel metal sheath 6, thereby greatly improving the measurement accuracy, high reliability, environmental resistance and service life.

[0023] Furthermore, the connecting member includes a baffle 7, a soft card block 71 and a card slot 72. The card slot 72 is provided on the front and rear surfaces of the stainless steel metal sheath 6. The longitudinal section of the card slot 72 is T-shaped. The soft card block 71 is slidably inserted into the inner wall of the card slot 72. In the present application, the material of the soft card block 71 is preferably polyurethane elastomer. The baffle 7 is fixedly installed on the outer surface of the soft card block 71. Track grooves 75 are provided on the inner walls on both sides of the card slot 72. Symmetrically distributed rotating grooves 73 are provided on the surface of both sides of the soft card block 71. The inner wall of the rotating groove 73 is rotatably sleeved with a rotating ball 74. The outer surface of the rotating ball 74 is rollingly connected to the inner wall of the track groove 75.

[0024] Working principle: By using the mutual cooperation between the connecting piece and the stainless steel metal sheath 6, the inner surface of the stainless steel metal sheath 6 is closely fitted with the upper substrate 2 and the lower substrate 1, so that a completely enclosed space is formed between the upper substrate 2 and the lower substrate 1;

[0025] When the upper and lower surfaces of the two stainless steel metal sheaths 6 are subjected to external pressure, the force they are subjected to is simultaneously transmitted to the upper substrate 2 and the lower substrate 1. At this time, the upper substrate 2 and the lower substrate 1 are deformed, and the distance d between the upper electrode 4 located on the lower surface of the upper substrate 2 and the lower electrode 5 located on the upper surface of the lower substrate 1 changes with the pressure change, and also satisfies the fixed function relationship of P=f(C). Since the connector and the stainless steel metal sheath 6 completely seal the upper substrate 2 and the lower substrate 1, when in contact with the measured medium, the medium cannot affect the pressure capacitance inside the stainless steel metal sheath 6, so the measurement accuracy, high reliability, environmental resistance and service life can be greatly improved;

[0026] In addition, when pressure acts on the upper substrate 2 and the lower substrate 1, the capacitance C value can be measured through the excitation circuit. The specific calculation formula is:

[0027]

[0028] Among them, ε represents the dielectric constant of the medium between the upper electrode 4 and the lower electrode 5, S represents the area of ​​the upper electrode 4 and the lower electrode 5, and d represents the distance between the upper electrode 4 and the lower electrode 5, thereby obtaining the value of the measured pressure P.

[0029] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A capacitive pressure sensor, comprising a lower substrate (1) and an upper substrate (2), characterized in that: A symmetrically distributed isolation sintered body (3) is fixedly installed between the lower substrate (1) and the upper substrate (2) for supporting the two. An upper electrode (4) is fixedly installed on the lower surface of the upper substrate (2) located between the opposite surfaces of the two isolation sintered bodies (3). A lower electrode (5) is fixedly installed on the upper surface of the lower substrate (1) located between the opposite surfaces of the two isolation sintered bodies (3). The outer surfaces of the upper substrate (2) and the lower substrate (1) are tightly fitted with a symmetrically distributed stainless steel metal sheath (6) through a connecting piece.

2. A capacitive pressure sensor according to claim 1, characterized in that: The connecting piece comprises a baffle (7), a soft clamping block (71) and a clamping slot (72). The clamping slot (72) is provided on the front and rear surfaces of the stainless steel metal sheath (6). The longitudinal section of the clamping slot (72) is in a T shape.

3. A capacitive pressure sensor according to claim 2, characterized in that: The soft card block (71) is slidably inserted into the inner wall of the card slot (72), the baffle (7) is fixedly mounted on the outer surface of the soft card block (71), and track sliding grooves (75) are provided on both inner walls of the card slot (72).

4. A capacitive pressure sensor according to claim 3, characterized in that: The two side surfaces of the soft clamping block (71) are provided with symmetrically distributed rotating grooves (73), and the inner wall of the rotating groove (73) is rotatably sleeved with a rotating ball (74).

5. A capacitive pressure sensor according to claim 4, characterized in that: The outer surface of the rotating ball (74) is rollingly connected to the inner wall of the track slide groove (75).

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