Dynamic pressure sensor

Abstract

The utility model relates to the technical field of pressure sensors, and provides a dynamic pressure sensor, which comprises a base and an induction diaphragm, an insulation layer is arranged in the base, an induction cavity and a reference cavity are arranged in the insulation layer and filled with silicone oil, the induction diaphragm is arranged in the induction cavity and divides the induction cavity into a positive pressure cavity and a negative pressure cavity, and the reference cavity is filled with silicone oil. A positive pressure metal pole piece and a negative pressure metal pole piece are fixed in the positive pressure cavity and the negative pressure cavity respectively, and two reference pole pieces corresponding to the positive pressure metal pole piece and the negative pressure metal pole piece are fixed in the reference cavity. And the positive pressure metal pole piece, the negative pressure metal pole piece, the insulating layer and the base are correspondingly provided with pressure channels for introducing the pressure on the positive side and the negative side to the sensing diaphragm. The beneficial effect of the utility model is that slow drift caused by temperature change and time aging can be compensated through the reference electrode.

Description

Technical Field

[0001] This utility model relates to the technical field of pressure sensors, specifically to a dynamic pressure sensor. Background Technology

[0002] Dynamic pressure sensors need to accurately capture rapidly changing pressure signals. Many dynamic pressure signals (such as turbulence, pulsation, and vibration) are tiny fluctuations superimposed on a very high static pressure. For example, in a 100-bar hydraulic system, the measured pressure pulsation might be only 0.1 bar. This requires the sensor to have extremely high signal-to-noise ratio and stability. When analyzing dynamic signals, we are primarily concerned with their frequency components. A tiny zero-point drift may not be noticeable in the time domain, but in the frequency domain it will manifest as a huge, erroneous low-frequency component, severely interfering with the interpretation of true low-frequency dynamic signals. Simultaneously, the sensor needs to maintain consistent sensitivity over a wide frequency range, i.e., a flat frequency response curve. Therefore, any factor that causes changes in sensitivity, such as temperature or static pressure variations, will distort the signal amplitude. Thus, any tiny drift or distortion will directly lead to a misinterpretation of dynamic phenomena. Utility Model Content

[0003] This invention proposes a dynamic pressure sensor that can compensate for slow drift caused by temperature changes and aging over time through a reference electrode.

[0004] Therefore, the technical solution adopted is as follows:

[0005] A dynamic pressure sensor includes a base and a sensing diaphragm. The base has an insulating layer, and the insulating layer contains a sensing cavity and a reference cavity, which are filled with silicone oil. The sensing diaphragm is located inside the sensing cavity and divides it into a positive pressure cavity and a negative pressure cavity. A positive pressure metal electrode and a negative pressure metal electrode are fixed in the positive pressure cavity and the negative pressure metal electrode, respectively. Two reference electrodes are fixed inside the reference cavity, corresponding to the positive pressure metal electrode and the negative pressure metal electrode. Pressure channels are correspondingly opened on the positive pressure metal electrode, the negative pressure metal electrode, the insulating layer, and the base to introduce the pressure on both the positive and negative sides to the sensing diaphragm.

[0006] A further technical solution is that the pressure channels corresponding to the positive pressure chamber and the negative pressure chamber are connected to corresponding pressure inlet chambers through an isolation diaphragm, and the isolation diaphragm has a corrugated structure.

[0007] A further technical solution is that the pressure chamber has a static pressure element inside, the static pressure element includes a static pressure cavity, the static pressure cavity has a static pressure diaphragm and is filled with silicone oil, and the static pressure cavity is connected to the pressure chamber through a static pressure channel and an isolation diaphragm.

[0008] A further technical solution is that the sensing diaphragm, positive pressure metal electrode, negative pressure metal electrode, reference electrode, and static pressure diaphragm all output electrical signals through leads and amplify the electrical signals through an amplifier circuit.

[0009] A further technical solution is that the dynamic sensor is symmetrically arranged with the sensing diaphragm as the center.

[0010] A further technical solution is that both the positive pressure metal electrode and the negative pressure metal electrode are attached and fixed to the inner wall of the sensing cavity of the insulating layer.

[0011] A further technical solution is that the insulating layer is a glass layer.

[0012] The working principle and beneficial effects of this application are as follows:

[0013] 1. By setting a reference electrode to form a reference capacitor, the reference capacitor can display the capacitance difference caused by environmental changes in real time, providing temperature drift compensation information for the measured capacitance. It compensates for the slow drift caused by temperature changes and aging over time. This enables the dynamic sensor to have the ability to self-calibrate in real time during operation and suppress drift, which greatly reduces the long-term error caused by temperature drift and aging, extends the calibration cycle and service life, ensures the stable output of the dynamic sensor in a long-term environment, and improves the stability and accuracy of the sensor.

[0014] 2. A static pressure element is set to measure the current static pressure value, specifically to compensate for zero-point and range drift caused by high static pressure. Static pressure compensation ensures that the dynamic pressure sensor can maintain a consistent zero point and sensitivity under different working static pressures, thereby ensuring that the dynamic data measured under different working conditions are comparable and accurate. Attached Figure Description

[0015] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0016] Figure 1 This is a schematic diagram of the overall structure of this application;

[0017] Figure 2 for Figure 1 A magnified structural diagram of part A in the middle.

[0018] In the diagram: 100, base; 1, sensing diaphragm; 2, insulating layer; 21, sensing cavity; 22, reference cavity; 211, positive pressure cavity; 212, negative pressure cavity; 31, positive pressure metal electrode; 32, negative pressure metal electrode; 33, reference electrode; 4, isolation diaphragm; 5, pressure chamber; 6, static pressure element; 61, static pressure cavity; 62, static pressure diaphragm; 7, lead wire; 8, amplifier circuit. Detailed Implementation

[0019] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this utility model.

[0020] like Figures 1-2 As shown, a dynamic pressure sensor includes a base 100 and a sensing diaphragm 1. The base 100 is made of stainless steel, which has high mechanical strength and can withstand the high pressure, impact and vibration of the process pipeline, protecting the fragile sensing diaphragm 1 inside. The base 100 has an insulating layer 2 made of glass, which is an excellent high-resistance layer to prevent current short circuits and has high sealing performance. At the same time, it can effectively combine the base 100 and the internal sensing diaphragm 1.

[0021] The insulating layer 2 has a sensing cavity 21 and a reference cavity 22 inside and is filled with silicone oil. The sensing diaphragm 1 is located inside the sensing cavity 21 and is divided into a positive pressure cavity 211 and a negative pressure cavity 212. A positive pressure metal electrode 31 and a negative pressure metal electrode 32 are fixed in the positive pressure cavity 211 and the negative pressure cavity 212, respectively. Two reference electrodes 33 are fixed inside the reference cavity 22, which are corresponding to the positive pressure metal electrode 31 and the negative pressure metal electrode 32. Pressure channels are opened on the positive pressure metal electrode 31, the negative pressure metal electrode 32, the insulating layer 2 and the base 100 to introduce the pressure on both the positive and negative sides to the sensing diaphragm 1.

[0022] In this embodiment, during use, the positive and negative pressures on both sides are introduced into the positive pressure chamber 211 and negative pressure chamber 212 respectively through the pressure channel. The silicone oil acts on both sides of the sensing diaphragm 1, causing the diaphragm 1 to deform. This changes the distance between the sensing diaphragm 1 and the positive and negative pressure metal electrodes 31 and 32, respectively, forming two measuring capacitors. The measuring circuit detects the change in the difference between these two capacitors. This capacitance difference is proportional to the displacement of the sensing diaphragm 1, which in turn is proportional to the differential pressure. Therefore, the capacitance difference can ultimately be converted into a standard linear electrical signal output. The dynamic sensor is symmetrically arranged with the sensing diaphragm 1 as the center. Only when the structures on both sides are completely symmetrical can the same differential pressure produce the same diaphragm displacement, ensuring a linear relationship between input and output and facilitating subsequent compensation for various factors.

[0023] Meanwhile, the reference electrode 33, enclosed within the reference cavity 22, is unaffected by static pressure and differential pressure. Furthermore, the reference electrode 33, along with the positive and negative metal electrodes 31 and 32, forms a reference capacitance within the same measurement environment. Therefore, external factors such as temperature, vibration, and aging have synchronous, unidirectional, or proportional interference on them. For example, if the support structures of the positive and negative metal electrodes 31 and 32 are miniaturized, the support structure of the reference cavity 22 of the reference electrode 33 will also be miniaturized to almost the same degree. This synchronous miniaturization will cause a common, slight shift in the baseline capacitance value of all capacitors. During fabrication, the positive and negative metal electrodes 31 and 32, as well as the reference electrode 33, need to be photolithographically etched onto the same silicon chip, with a spacing of only micrometers or millimeters between them, further ensuring temperature and environmental uniformity.

[0024] This ensures that the change in the reference capacitance due to environmental variations is consistent with the changes in the two measuring capacitors. This change is then used to compensate for the changes in the measuring capacitors, guaranteeing the accuracy of the dynamic sensor. It enables the sensor to perform real-time self-calibration and suppress drift during operation, significantly reducing long-term errors caused by temperature drift and aging, and extending the calibration cycle and lifespan.

[0025] The pressure channels corresponding to the positive pressure chamber 211 and the negative pressure chamber 212 are connected to the corresponding pressure inlet chamber 5 via the isolation diaphragm 4, which has a corrugated structure. On one hand, the isolation diaphragm 4 completely isolates corrosive, viscous, particle-containing, or high-temperature process media from the delicate and fragile sensing elements inside the sensor. It also transmits pressure to the sensing diaphragm 1 without loss by squeezing out the internal silicone oil through its own slight deformation. On the other hand, by replacing the isolation diaphragm 4 with different materials, the same sensor core can be used to measure various different media, which greatly improves the product's versatility and reduces design and manufacturing costs. Furthermore, the corrugated design of the isolation diaphragm 4 improves sensitivity, enabling it to generate sufficient displacement under very low pressure.

[0026] Similarly, to eliminate the negative impact of high static pressure on the accuracy of differential pressure measurement and thus achieve ultra-high precision measurement, another embodiment of this application provides a static pressure element 6 inside the pressure chamber 5. The static pressure element 6 includes a static pressure cavity 61, which contains a static pressure diaphragm 62 filled with silicone oil. The static pressure cavity 61 is connected to the pressure chamber 5 via a static pressure channel and an isolation diaphragm 4. The current static pressure value is monitored in real time by the static pressure diaphragm 62. The microprocessor reads this static pressure value and queries its internally stored static pressure error model to find the corresponding zero-point correction value and range correction coefficient. Using these correction parameters, the processor performs real-time mathematical calculations on the raw output signal of the main dynamic sensor, thereby offsetting the error caused by static pressure and further enhancing the long-term stability of the sensor.

[0027] In the above embodiments, the sensing diaphragm 1, positive pressure metal electrode 31, negative pressure metal electrode 32, reference electrode 33, and static pressure diaphragm 62 all output electrical signals through lead wire 7 and amplify the electrical signals through amplifier circuit 8. Amplifier circuit 8 converts a charge signal that is difficult to measure and easily lost into a voltage signal that is easy to process and stable and reliable.

[0028] Both the positive pressure metal electrode 31 and the negative pressure metal electrode 32 are attached and fixed to the inner wall of the sensing cavity 21 of the insulating layer 2, providing a certain rigid constraint for the intermediate sensing diaphragm 1. Thus, when the deformation of the sensing diaphragm 1 causes it to adhere to the positive pressure metal electrode 31 or the negative pressure metal electrode 32, it is rigidly supported by the insulating layer 2 and cannot deform further. This prevents the sensing diaphragm 1 from being subjected to excessive instantaneous pressure, causing overload and resulting in the rupture of the sensing diaphragm 1.

[0029] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A dynamic pressure sensor, comprising a base (100) and a sensing diaphragm (1), characterized in that: The base (100) has an insulating layer (2) inside. The insulating layer (2) has a sensing cavity (21) and a reference cavity (22) inside and is filled with silicone oil. The sensing diaphragm (1) is located inside the sensing cavity (21) and is divided into a positive pressure cavity (211) and a negative pressure cavity (212). A positive pressure metal electrode (31) and a negative pressure metal electrode (32) are fixed in the positive pressure cavity (211) and the negative pressure cavity (212) respectively. Two reference electrodes (33) are fixed inside the reference cavity (22) and are correspondingly arranged with the positive pressure metal electrode (31) and the negative pressure metal electrode (32). Pressure channels are opened on the positive pressure metal electrode (31), the negative pressure metal electrode (32), the insulating layer (2) and the base (100) to introduce the pressure on both sides to the sensing diaphragm (1).

2. A dynamic pressure sensor according to claim 1, characterized in that, The pressure channels corresponding to the positive pressure chamber (211) and the negative pressure chamber (212) are connected to the corresponding pressure chambers (5) through the isolation diaphragm (4), which has a corrugated structure.

3. A dynamic pressure sensor according to claim 2, characterized in that, The pressure chamber (5) has a static pressure element (6) inside. The static pressure element (6) includes a static pressure cavity (61). The static pressure cavity (61) has a static pressure diaphragm (62) inside and is filled with silicone oil. The static pressure cavity (61) is connected to the pressure chamber (5) through a static pressure channel and an isolation diaphragm (4).

4. A dynamic pressure sensor according to claim 2, characterized in that, The sensing diaphragm (1), positive pressure metal electrode (31), negative pressure metal electrode (32), reference electrode (33), and static pressure diaphragm (62) all output electrical signals through leads (7) and amplify the electrical signals through an amplifier circuit (8).

5. A dynamic pressure sensor according to claim 1, characterized in that, The dynamic sensor is symmetrically arranged with the sensing diaphragm (1) as the center.

6. A dynamic pressure sensor according to claim 1, characterized in that, Both the positive pressure metal electrode (31) and the negative pressure metal electrode (32) are attached and fixed to the inner wall of the sensing cavity (21) of the insulating layer (2).

7. A dynamic pressure sensor according to claim 1, characterized in that, The insulating layer (2) is a glass layer.

Images