Miniature dual-redundancy pressure sensor

Abstract

The invention belongs to the pressure measurement technology of a pressure sensor, and relates to a high-precision and miniaturized dual-redundancy pressure sensor. A micro-miniature dual-channel independent working pressure sensor with the precision reaching 0.25% needs to be developed in a targeted manner. A pressure sensitive assembly is installed at the front end of an outer cylinder, a circuit assembly is installed in the outer cylinder, a wire outlet column and a plug are installed at the rear end of the outer cylinder, the pressure sensitive assembly is provided with a filler neck and a pressure core which are integrated, and the pressure core comprises two pressure sensing elements; the circuit assembly comprises two circuit boards which are used for providing constant-current power supply for the two pressure sensing elements respectively, conducting temperature compensation, amplification and zero bias on voltage signals output by the two pressure sensing elements, and outputting voltage signals in direct proportion to pressure. Compared with a traditional silicon piezoresistive sensor, the volume of the silicon piezoresistive sensor is reduced by 78.3%, and the precision is improved from 1.0% to 0.25%.

Description

Technical Field

[0001] The invention belongs to the pressure measurement technology of a pressure sensor and relates to a high-precision, miniaturized dual-redundancy pressure sensor. Background Art

[0002] The miniature, dual-redundancy, high-precision pressure sensor is a product developed to meet the needs of electronic program controllers for measuring external pressure. Due to the stringent requirements of program controllers on volume, weight and accuracy, it is necessary to develop a miniature, dual-channel, independently working pressure sensor with an accuracy of 0.25%.

[0003] Traditional architectural design can no longer meet the requirements. Summary of the invention

[0004] The purpose of the present invention is to adopt key technologies such as dual-redundancy non-oil-filled core packaging, fusion of nozzle and pressure core, integrated conditioning chip and high-precision temperature compensation technology of sensor, and complete the development plan of micro-pressure core, high-precision debugging and dual-channel pressure sensor.

[0005] The present invention provides a miniature dual-redundancy pressure sensor, wherein a pressure sensitive component is installed at the front end of an outer cylinder, a circuit component is installed inside the outer cylinder, and an outlet column and a plug are installed at the rear end of the outer cylinder. The pressure sensitive component has an integrated nozzle and a pressure core, and the pressure core includes two pressure-sensitive elements; the circuit component includes two circuit boards, which respectively provide constant current power supply to the two pressure-sensitive elements, and perform temperature compensation, amplification and zero-position bias on the voltage signals output by the two pressure-sensitive elements, and output a voltage signal proportional to the pressure.

[0006] Advantageously, the pressure core is connected to the circuit board via an FPC soft board.

[0007] Advantageously, the pressure core is integrated in a single tube shell in the pressure sensitive component, and an isolation film is sprayed on the wafer of the pressure sensitive element.

[0008] Advantageously, the pressure sensitive component and the outer cylinder, and the outer cylinder and the outlet column are fixed by welding.

[0009] Advantageously, the circuit assembly is fixed in the outer cylinder by filling HM-309 silicone sealant.

[0010] Advantageously, a BC201 conditioning chip is provided on the circuit assembly.

[0011] Advantageously, the plug adopts a GJB599 macro-series electrical connector.

[0012] Advantageously, the sensor throw-out cable and the plug are supported and fixed by the outlet column.

[0013] Beneficial effects: By adopting key technologies such as dual-redundancy non-oil-filled core packaging, fusion of nozzle and pressure core, integrated conditioning chip and high-precision temperature compensation technology of sensor, we have completed the development of micro-pressure core, high-precision debugging and dual-channel pressure sensor.

[0014] This design breaks the conventional design ideas and innovatively carries out product architecture design. Compared with traditional silicon piezoresistive sensors, the sensor volume of this solution is reduced by 78.3% and the accuracy is improved from 1.0% to 0.25%.

[0015] The features, functions, and advantages that have been discussed can be achieved independently in various examples or may be combined in yet other examples. Further details of the examples can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Examples, as well as preferred modes of use, other objects and description thereof, will be best understood by reference to the following detailed description of examples of the invention when read in conjunction with the accompanying drawings, in which:

[0017] Figure 1 Schematic diagram of the appearance of the miniature dual-redundancy pressure sensor of the present invention;

[0018] Figure 2 It is a schematic diagram of the internal structure of a miniature dual-redundancy pressure sensor;

[0019] Figure 3 It is a schematic diagram of the appearance of a dual-redundancy pressure sensor;

[0020] Figure 4 This is the working principle diagram of the dual redundant pressure sensor.

[0021] 1-pressure sensitive component, 2-outer tube, 3-outlet column, 4-circuit component, 5-plug DETAILED DESCRIPTION

[0022] The disclosed examples will be more fully described with reference to the accompanying drawings, in which some (but not all) of the disclosed examples are shown. In fact, many different examples may be described and these examples should not be construed as limited to the examples set forth herein. Instead, these examples are described so that this disclosure will be thorough and complete and will fully convey the scope of the disclosure to those skilled in the art.

[0023] Now refer to Figure 1 and Figure 2 The example dual-redundancy pressure sensor includes a pressure sensitive component 1, an outer tube 2, a circuit component 3, an outlet column 4 and a plug 5. The circuit component 3 is welded to the pins of the pressure sensitive component 1, and then pre-fixed by glue filling, and protected by the outer tube 2. The outlet column 4 and the plug 5 are used for signal output.

[0024] The pressure sensitive component 1 is mainly composed of a nozzle and a pressure core. The pressure sensitive component is the part that connects the product to the outside world and meets the following requirements:

[0025] a) have sufficient mechanical strength;

[0026] b) The materials used should have excellent machining and welding properties; the material used should be stainless steel with a grade of 0Cr18Ni9;

[0027] c) The material has good corrosion and protection properties to ensure the normal transmission of pressure;

[0028] The outer cylinder 2 provides physical protection for the internal circuit components, electronic components and cables of the product. At the same time, it strengthens the structural strength of the entire product by assembling and connecting with the pressure sensitive component 1 and the outlet column 4. The pressure sensitive component 1 and the outer cylinder 2, and the outer cylinder 2 and the outlet column 4 are fixed by welding.

[0029] Circuit assembly 3 can provide constant current power supply for pressure sensitive assembly 1, and at the same time, temperature compensate, amplify and zero-bias the voltage signal output by pressure sensitive assembly 1, and output a voltage signal proportional to the pressure. Circuit assembly 3 is fixed in outer tube 2 by filling HM-309 organic silicon sealant, and has good thermal conductivity and insulation performance. BC201 conditioning chip is provided on circuit assembly 3, and the pressure core is a dual-redundancy core, which can realize dual-redundancy demodulation of pressure.

[0030] The outlet column 4 is a supporting and fixing component for the sensor cable and the plug 5 .

[0031] The plug 5 adopts the GJB599 macro-type series electrical connector, which has the advantages of small size, light weight, and high contact pair density.

[0032] This plan includes the following design elements

[0033] a. Double redundancy high-precision core design, fusion design of nozzle and core

[0034] See also Figure 3 Due to the limitation of product volume, the volume allocated to the pressure core is only 14mm in diameter and 4mm in height. Double redundancy and high precision are also required. Through overall volume allocation, the nozzle 1 is integrated with the pressure core. The nozzle 1, isolation diaphragm, and core shell are integrated and welded together, making the nozzle a part of the pressure core, ensuring the miniaturization of the sensor front end.

[0035] Through the customized shell, the pressure core integrated inside the single shell includes two pressure sensing elements, and the dual-redundancy pressure measurement function is realized through the two pressure sensing elements. At the same time, in order to meet the high-precision requirements of the core, non-oil-filled isolation technology is adopted, and the environmental adaptability requirements are achieved by spraying an isolation film on the wafer of the pressure sensing element. The miniaturization, high-precision and dual-redundancy requirements of the pressure core are met. Lay the foundation for the overall performance and accuracy requirements of the sensor.

[0036] b. High-precision miniaturized, integrated conditioning chip

[0037] The chip preparation is a highly integrated dedicated chip for signal conditioning and transmission output of resistive or voltage type sensors such as silicon piezoresistive pressure sensors, thermocouples, RTDs and other sensors, as well as post-stage 0 to 2 times high-precision adjustable sensitivity compensation.

[0038] c. High-precision temperature compensation of the sensor

[0039] The sensor adopts the compensation scheme of the signal conditioning circuit, which obtains the corresponding relationship between the output of the sensor chip and the pressure and temperature by pre-calibrating under standard temperature and pressure conditions. According to the data of the calibrated temperature and pressure points, the tool software analyzes and processes them, evaluates the corresponding rules of output, temperature and pressure outside the calibration points, and converts the limited calibration conditions into a corresponding matrix of temperature, pressure and output relationships in a grid format. The more calibration temperature points selected and the more detailed the calibration data, the higher the compensation accuracy of the sensor, but the cost will also increase. By studying the temperature output curve of the compensated object, reducing the calibration points in the flat section and increasing the calibration points in the inflection point section, a higher compensation accuracy can be obtained more economically.

[0040] The temperature compensation scheme of the sensor can be calibrated and compensated through the lead wires after the meter is sealed. The online calibration function can be realized on the machine or on-site working conditions. The segmented DAC calibration can ensure the output accuracy as much as possible when the temperature range span is large and causes output offset. The sensor can be zeroed at the factory and the output drift can be zeroed and adjusted using calibration equipment under normal temperature conditions.

[0041] d. Internal wire-free structure design

[0042] Due to the volume limitation of the sensor, the electrical connection between the double-redundant pressure core and the circuit board cannot be achieved through ordinary wires. Innovative technology is adopted to connect two circuit boards with the double-redundant core using FPC soft boards. At the same time, due to the small size of the product, the circuit board cannot be fixed by screws, and the circuit board needs to be fixed by glue.

[0043] Descriptions of different advantageous arrangements have been presented for purposes of illustration and description, but the description is not intended to be exclusive or limited to examples of the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. Additionally, different advantageous examples may be described as having different advantages over other advantageous examples. The selected example or examples are selected and described in order to best illustrate the principles of the examples, practical applications, and to enable those of ordinary skill in the art to understand the disclosure as having various examples with various modifications suitable for the particular use contemplated.

Claims

1. A miniature dual-redundancy pressure sensor, characterized in that: A pressure sensitive component (1) is installed at the front end of the outer tube (2), a circuit component (3) is installed inside the outer tube (2), and an outlet column (4) and a plug (5) are installed at the rear end of the outer tube (2). The pressure sensitive component (1) has an integrated nozzle and a pressure core, and the pressure core includes two pressure-sensitive elements; the circuit component (3) includes two circuit boards, which respectively provide constant current power supply to the two pressure-sensitive elements, and perform temperature compensation, amplification and zero-position offset on the voltage signals output by the two pressure-sensitive elements, and output a voltage signal proportional to the pressure.

2. The miniature dual-redundancy pressure sensor according to claim 1, characterized in that: The pressure core is connected to the circuit board via an FPC soft board.

3. The miniature dual-redundancy pressure sensor according to claim 1, characterized in that: The pressure core is integrated in a single tube shell in the pressure sensitive component (1), and an isolation film is sprayed on the wafer of the pressure sensitive element.

4. The miniature dual-redundancy pressure sensor according to claim 1, characterized in that: The pressure sensitive component (1) and the outer cylinder (2), and the outer cylinder (2) and the outlet column (4) are fixed by welding.

5. The miniature dual-redundancy pressure sensor according to claim 1, characterized in that: The circuit assembly (3) is fixed in the outer cylinder (2) by injecting HM-309 organic silicon sealant.

6. The miniature dual-redundancy pressure sensor according to claim 1, characterized in that: A BC201 conditioning chip is provided on the circuit component (3).

7. The miniature dual-redundancy pressure sensor according to claim 1, characterized in that: The plug (5) adopts a GJB599 macro-series electrical connector.

8. The miniature dual-redundancy pressure sensor according to claim 1, characterized in that: The cable outlet column (4) is used to support and fix the sensor cable and the plug (5).

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