Diaphragm covered differential pressure sensor

Abstract

The utility model relates to a diaphragm covering type differential pressure sensor, including sensor body, the sensor body outside distribution has response area, and the response area is distributed with diaphragm, and the diaphragm size is same with the outer contour of response area, and the diaphragm completely covers the end face of response area, and the edge of diaphragm is fixed in the sensor body edge circumference, and the sensor body is installed with response chip, and the sensor body is distributed with response cavity that is conducted with response area, and response chip is installed on the response cavity top. Thus, the diaphragm can completely cover the response area and only the diaphragm contacts medium, and the corrosion -resistant film material that can be selected as needed can effectively block the direct contact of medium and sensor body and internal response chip, avoid the damage of medium erosion to core component. Meanwhile, it can be flexible and adaptable to the measurement scene of different corrosion characteristics such as acidity, alkalinity, greatly widen the application range of sensor.

Description

Technical Field

[0001] This utility model relates to a sensor, and more particularly to a diaphragm-covered differential pressure sensor. Background Technology

[0002] Differential pressure sensors are key devices in industrial measurement, and their performance reliability and cost control have always been core directions for technological development. In existing technologies, Chinese patent CN114689227A discloses a thin-film pressure sensor, which isolates the strain gauge from the external medium by placing it in a sealed chamber, preventing damage to the strain gauge due to environmental influences. However, this technology does not address the issue of coordinating material cost optimization between the sensor body and the components in contact with the medium. Meanwhile, regarding diaphragm mounting structures, existing technologies have improved connection stability. For example, Chinese patent CN218628761U discloses a diaphragm mounting structure for a wind pressure sensor, which uses an annular groove and a hot-melt molded annular pressure plate to limit and fix the diaphragm, improving installation sealing. However, this structure does not address the issue of adapting to the corrosiveness of the medium in differential pressure measurement scenarios, nor does it address the differentiated material selection between the diaphragm and the sensor body. In addition, Chinese patent CN108918019B discloses a differential pressure sensor for DPF exhaust gas treatment systems, which uses a ceramic capacitor flat diaphragm structure to achieve high temperature resistance and corrosion resistance. However, its overall structure has the problems of large amount of expensive materials and complex production process.

[0003] Therefore, existing differential pressure sensor technology still has three shortcomings in practical applications: First, to ensure corrosion resistance, the sensor body and diaphragm are often made of the same expensive materials, such as Hastelloy or 316L, resulting in high manufacturing costs. Second, the fixing structure of the diaphragm and body is prone to edge stress concentration, affecting measurement accuracy and service life. Third, the homogenization of diaphragm thickness design makes it difficult to balance deformation sensitivity and structural strength.

[0004] In view of the above-mentioned shortcomings, the designer actively researched and innovated in order to create a diaphragm-covered differential pressure sensor, which would have greater industrial application value. Utility Model Content

[0005] To address the aforementioned technical problems, the purpose of this utility model is to provide a diaphragm-covered differential pressure sensor.

[0006] The present invention discloses a diaphragm-covered differential pressure sensor, comprising a sensor body, wherein: a sensing area is distributed outside the sensor body, a diaphragm is distributed on the sensing area, the size of the diaphragm is the same as the outer contour of the sensing area, the diaphragm completely covers the end face of the sensing area, and the edge of the diaphragm is fixed to the circumferential edge of the sensor body; a sensing chip is installed inside the sensor body, and a sensing cavity communicating with the sensing area is distributed inside the sensor body, the sensing chip being installed above the sensing cavity.

[0007] Furthermore, in the aforementioned diaphragm-covered differential pressure sensor, the edge of the diaphragm is fixed to the edge of the sensor body by laser welding; or, the edge of the diaphragm is fixed to the edge of the sensor body by an adhesive layer.

[0008] Furthermore, in the aforementioned diaphragm-covered differential pressure sensor, the edge of the diaphragm is provided with a 90° inward folding edge structure, which covers the edge of the sidewall of the sensor body.

[0009] Furthermore, in the aforementioned diaphragm-covered differential pressure sensor, the edge of the sensor body is provided with an annular groove, and the edge of the diaphragm is embedded in the groove.

[0010] Furthermore, in the aforementioned diaphragm-covered differential pressure sensor, the end face of the sensor body is provided with an annular protrusion, and the corresponding position of the diaphragm is provided with a matching limiting notch, with the annular protrusion embedded in the limiting notch.

[0011] Furthermore, in the aforementioned diaphragm-covered differential pressure sensor, the thickness of the central region of the diaphragm is 0.1-0.2 mm, and the thickness of the edge region is 0.3-0.5 mm.

[0012] Furthermore, in the aforementioned diaphragm-covered differential pressure sensor, a sensing gap is distributed between the sensor body and the diaphragm, and the sensing gap is ≤0.05mm.

[0013] Furthermore, in the aforementioned diaphragm-covered differential pressure sensor, the surface of the diaphragm is distributed with several recessed sensing patterns.

[0014] By means of the above solution, this utility model has at least the following advantages:

[0015] 1. The diaphragm completely covers the sensing area, with only the diaphragm in contact with the medium. Corrosion-resistant diaphragm materials can be selected as needed, effectively blocking direct contact between the medium and the sensor body and internal sensing chip, preventing damage to core components from media corrosion. It can also flexibly adapt to measurement scenarios with different corrosive properties, such as acidic and alkaline conditions, significantly expanding the sensor's applicability.

[0016] 2. It eliminates the need to use high-cost, corrosion-resistant materials for both the sensor body and the diaphragm. Only the diaphragm needs to be made of a suitable special material, while the sensor body can be downgraded to low-cost 304 stainless steel, reducing the amount of expensive materials used. This eliminates the need for complex special material processing of the sensor body, simplifying the production process.

[0017] 3. The diaphragm is firmly bonded, preventing it from detaching under differential pressure. This prevents edge cracking over long-term use, significantly improving the overall structure's resistance to wear and stability, and extending the sensor's lifespan.

[0018] 4. The overall structure is simple, and existing differential pressure sensors can be modified, making it highly versatile.

[0019] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the diaphragm-covered differential pressure sensor, including the diaphragm assembly structure of the sensor.

[0021] The meanings of the labels in the figures are as follows.

[0022] Detailed Implementation

[0023] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0024] like Figure 1 The diaphragm-covered differential pressure sensor includes a sensor body 1. The outer surface of the sensor body 1 has a sensing area 2 for sensing differential pressure, preferably circumferentially distributed around the periphery of the sensor body 1. A diaphragm 3 covers the sensing area 2, the size of which perfectly matches the outer contour of the sensing area 2, completely covering its end face and achieving effective circumferential differential pressure sensing. Furthermore, the edge of the diaphragm 3 is fixed circumferentially along the edge of the sensor body 1, achieving a closed-loop distribution. This ensures that during measurement, the medium only contacts the diaphragm 3 and does not directly contact the sensor body 1, preventing medium erosion. During implementation, a sensing chip 4 is fixedly installed inside the sensor body 1. Sensing cavities 5, which are connected to the sensing area 2, are distributed within the sensor body 1, and the sensing chip 4 is mounted above the sensing cavities 5. Thus, the differential pressure appearing in the sensing cavities 5 can be captured by the sensing chip 4 in real time.

[0025] In a preferred embodiment of this invention, regarding the fixing method of the diaphragm 3, this embodiment employs laser welding. After aligning the edge of the diaphragm 3 with the edge of the sensor body 1, uniform laser welding is performed along the circumferential direction of the edge. Simultaneously, the spacing of the welding points can be adjusted according to the body size, for example, one welding point every 5mm, ensuring the sealing and structural strength of the connection. Furthermore, the edge of the diaphragm 3 has a 90° inward-folded edge-wrapping structure. The height of this edge-wrapping structure matches the thickness of the sidewall of the sensor body 1, and the edge-wrapping structure completely covers the edge of the sidewall of the sensor body 1. This enhances the connection stability between the diaphragm 3 and the body 1, preventing the diaphragm 3 from detaching under differential pressure.

[0026] To optimize the stress distribution of diaphragm 3, its thickness is designed differently, with a thickness of 0.1-0.2 mm in the central region and 0.3-0.5 mm in the edge region. This structural design gives the central region higher deformation sensitivity, making it easier to detect minute differential pressure changes. At the same time, the increased thickness in the edge region enhances structural strength and prevents edge cracking after long-term use.

[0027] Furthermore, a sensing gap is provided between the sensor body 1 and the diaphragm 3. The size of this sensing gap is ≤0.05mm, and the size of the gap can be controlled by setting tiny protrusions on the edge of the body 1. This ensures that the diaphragm 3 can deform normally under differential pressure and transmit the signal to the sensing chip 4, while avoiding signal delay or distortion caused by an excessively large gap. In addition, several recessed sensing patterns are distributed on the surface of the diaphragm 3. The patterns are radially distributed along the center of the diaphragm 3, and the depth of the patterns is 0.01-0.02mm, which can be adjusted according to the thickness of the diaphragm 3. These patterns can enhance the response speed of the diaphragm 3 to changes in differential pressure, further improving the measurement accuracy of the sensor.

[0028] Example 1

[0029] The core structure of this diaphragm-covered differential pressure sensor, including the sensor body 1, is the same as that of the aforementioned diaphragm-covered differential pressure sensor, including the sensor body 1. The difference lies in the fixing method and positioning structure of the diaphragm 3. Specifically:

[0030] The edge of diaphragm 3 is fixed with an adhesive layer, which can be a high-temperature resistant and corrosion-resistant adhesive, such as epoxy resin adhesive, applied to the edge of sensor body 1. After the edge of diaphragm 3 is attached to the edge of body 1, it is cured at room temperature or low temperature, such as 60-80℃. The curing time can be adjusted according to the adhesive properties, and can be preset to 2 to 4 hours to ensure good sealing and resistance to media corrosion at the bonded area. Furthermore, an annular groove is provided on the edge of sensor body 1. The cross-section of the annular groove is U-shaped, and the depth of the groove matches the thickness of the edge of diaphragm 3. For example, when the thickness of the edge of diaphragm 3 is 0.3mm, the groove depth is set to 0.3mm. During assembly, the edge of diaphragm 3 is directly embedded in this annular groove, and the inner wall of the groove acts as a positioning element to prevent the diaphragm 3 from shifting during assembly.

[0031] Furthermore, the end face of the sensor body 1 is also provided with an annular protrusion. The diameter of the annular protrusion is smaller than the diameter of the sensing area 2, and the diaphragm 3 has a matching limiting notch at the position corresponding to the annular protrusion. During assembly, the annular protrusion is embedded in the limiting notch, further achieving precise alignment between the diaphragm 3 and the sensing area 2, and preventing the diaphragm 3 from shifting and affecting the measurement accuracy. In this embodiment, the thickness design, sensing gap size, and surface engraving pattern of the diaphragm 3 are consistent with the previous embodiment, ensuring that the sensor has the same stress distribution optimization effect and measurement sensitivity.

[0032] In the above embodiments, the diaphragm 3 is used as the only component in contact with the medium. The appropriate corrosion-resistant material can be selected based on the characteristics of the measured medium. For example, a Hastelloy diaphragm 3 is used when measuring acidic media, and a titanium alloy diaphragm 3 is used when measuring alkaline media. Therefore, the sensor body 1 does not need to use high-cost corrosion-resistant materials; the traditional 316L material can be downgraded to 304 material, significantly reducing material costs. In other words, for scenarios requiring the measurement of special corrosive media, it is not necessary to use high-priced materials such as Hastelloy or precious metals for both the sensor body 1 and the diaphragm 3; only the diaphragm 3 needs to be replaced with the corresponding special material. This not only reduces the amount of expensive materials used but also simplifies the production process, improves production efficiency, and accurately matches the customer's on-site medium measurement needs, ensuring the sensor's applicability and reliability.

[0033] Furthermore, the directions or positional relationships described in this utility model are based on the directions or positional relationships shown in the accompanying drawings. They are only for the purpose of facilitating the description of this utility model and simplifying the description, and are not intended to indicate or imply that the device or structure referred to must have a specific orientation, or to operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0034] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A diaphragm covered differential pressure sensor comprising a sensor body, characterized in that: The sensor body has a sensing area distributed outside, and a diaphragm is distributed on the sensing area. The size of the diaphragm is the same as the outer contour of the sensing area. The diaphragm completely covers the end face of the sensing area, and the edge of the diaphragm is fixed to the circumferential edge of the sensor body. A sensing chip is installed inside the sensor body, and a sensing cavity that is connected to the sensing area is distributed inside the sensor body. The sensing chip is installed above the sensing cavity.

2. The diaphragm covered differential pressure sensor of claim 1, wherein: The edge of the diaphragm is fixed to the edge of the sensor body by laser welding; or, the edge of the diaphragm is fixed to the edge of the sensor body by an adhesive layer.

3. The diaphragm covered differential pressure sensor of claim 1, wherein: The diaphragm edge is provided with a 90° inward folding edge structure, which covers the edge of the sensor body sidewall.

4. The diaphragm covered differential pressure sensor of claim 1, wherein: The sensor body has an annular groove on its edge, and the edge of the diaphragm is embedded in the groove.

5. The diaphragm covered differential pressure sensor of claim 1, wherein: The end face of the sensor body is provided with an annular protrusion, and the diaphragm is provided with a matching limiting notch at the corresponding position, with the annular protrusion embedded in the limiting notch.

6. The diaphragm covered differential pressure sensor of claim 1, wherein: The thickness of the central region of the diaphragm is 0.1-0.2 mm, and the thickness of the edge region is 0.3-0.5 mm.

7. The diaphragm covered differential pressure sensor of claim 1, wherein: There is a sensing gap between the sensor body and the diaphragm, and the sensing gap is ≤0.05mm.

8. The diaphragm covered differential pressure sensor of claim 1, wherein: The surface of the diaphragm has several recessed sensing patterns.

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