Pressure instrument for realizing remote temperature difference correction

Abstract

The invention relates to the technical field of industrial automation, and relates to a pressure instrument for realizing remote temperature difference correction, which comprises a remote transmission flange structure, a base sensor unit, a controller and a pressure instrument body. Errors caused by temperature inconsistency of remote pressure measurement points are corrected, temperature correction of pressure / differential pressure sent to a controller and derived liquid level / flow measurement values is completed, precision is improved, and field instruments are convenient to install and maintain. Meanwhile, field replacement can be conveniently carried out, additional punching and installation of auxiliary instruments or other equipment are not needed, engineering construction and follow-up maintenance are facilitated, the existing field installation mode and wiring are not affected, on-site remote temperature and pressure compensation can be achieved, and the measurement precision of variables such as field pressure / differential pressure and derived liquid level / flow is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial automation, and particularly to a pressure instrument for realizing remote temperature difference correction. Background Art

[0002] As an important device in the industrial automation production process, the pressure / differential pressure instrument is not only used for the measurement of pressure / differential pressure signals, but also can be used to measure physical quantities such as liquid level and flow rate in cooperation with accessories such as remote transmission flanges and flow orifice plates. Therefore, it has a very wide range of market applications.

[0003] Limited by the installation requirements of process pipelines, the measured structural components in the measurement process of remote transmission pressure instruments are usually far away from the actual pressure measurement positions. This will cause measurement errors due to the inconsistency of environmental parameters such as temperature and static pressure at the actual measured positions and the temperature and pressure at the positions where the instrument sensors are located. At present, additional temperature and static pressure sensors need to be installed on the project, and after being sent to the upper control system, the control system performs temperature and pressure compensation. This solution not only increases the number and cost of on-site instruments, but also requires engineers to do additional configuration work, and is not conducive to the replacement and maintenance of on-site instruments. Summary of the Invention

[0004] (I) Technical Problems to be Solved

[0005] To solve the above technical problems, the present invention provides a pressure instrument for realizing remote temperature difference correction.

[0006] (II) Technical Solutions

[0007] Based on this, the present invention provides the following technical solution: A pressure instrument for realizing remote temperature difference correction, including a remote transmission flange structure, a base sensor unit, and a pressure instrument body. The remote transmission flange structure is installed on both sides of the process measured structural component. Both ends of the base sensor are respectively connected to the middle parts of the two groups of remote transmission flange structures. After the measurement signal of the base sensor unit is converted and calculated by the pressure instrument body, a data connection is established with the controller;

[0008] The remote transmission flange structure includes a remote transmission flange, a temperature sensor, a long cable, a connection sleeve, and a filling oil pipe. The remote transmission flange is fixed to the right end of the process measured structural component. The temperature sensor is connected to the pressure instrument body by a long cable. The filling oil pipe is inserted into the left end of the connection sleeve.

[0009] Preferably, a threaded groove is provided at the upper left end of the remote transmission flange, and the temperature sensor is in threaded cooperation with the inner side of the threaded groove, which is convenient for fixing and positioning the temperature sensor.

[0010] Preferably, a positioning groove starts from the middle of the left end of the remote flange, and the connecting sleeve is embedded inside the positioning groove, facilitating the installation and fixation of the connecting sleeve.

[0011] Preferably, a connecting groove is provided at the right end of the positioning groove, and the oil filling pipe passes through the connecting groove on the positioning groove and penetrates into the interior of the process structure to be measured, and the oil filling pipe is connected to the base sensor unit.

[0012] Preferably, a terminal is provided at the right end inside the thread groove, and the right end of the temperature sensor contacts the terminal.

[0013] Preferably, the MCU inside the pressure gauge body uses STM32G030, which integrates a 12-bit ADC converter inside, and can realize signal sampling of 2 external temperature sensors 22.

[0014] Preferably, the specific working steps of the MCU inside the pressure gauge body are as follows:

[0015] Step S1: The MCU is initialized;

[0016] Step S2: The MCU completes the pressure / differential pressure sampling and calculation of the base sensor unit;

[0017] Step S3: Subsequently, the temperature sampling and compensation calculation of the process structure to be measured are carried out;

[0018] Step S4: Next, the remote temperature sampling is carried out;

[0019] Step S5: The remote temperature difference is corrected to obtain an accurate pressure / differential pressure measurement value;

[0020] Step S6: The derivative measurement value is calculated through the liquid level or flow formula, and finally becomes a standard 4-20mA or 1-5V superimposed HART digital carrier through DA conversion and is sent to the controller system.

[0021] Preferably, the pressure gauge body is externally provided with a 24-bit ADC, and the 24-bit ADC uses AD7799 to ensure the measurement accuracy and sampling rate of the pressure sensor of the process structure to be measured.

[0022] Preferably, the circuit output part of the pressure gauge body adopts the method of AD5421+AD5700 to output a 4-20mA superimposed HART digital signal.

[0023] Preferably, the temperature sensor uses an armored three-wire pt100, and the base sensor unit includes a pressure / differential pressure sensor and an attached temperature-sensitive element, which are installed and fixed in a threaded manner with the thread groove; the three lead-out wires of the pt100 are connected to the on-site pressure gauge through a shielded oil filling pipe.

[0024] Preferably, the temperature sensor uses an NTC thermistor ERT-J1VG103FA and is mounted inside the diaphragm of the remote flange by means of surface mounting. A shielded wire is used to connect to the inside of the field instrument. The base sensor unit includes a differential pressure sensor, a pressure sensor, and an internal temperature sensor, and integrates an independent ADC as well as a front-end signal processing and calculation unit to achieve multi-variable measurement and digital value output of the base sensor.

[0025] (III) Advantageous Effects

[0026] Compared with the prior art, the present invention provides a pressure instrument for realizing remote temperature difference correction, which has the following advantageous effects:

[0027] The pressure instrument for realizing remote temperature difference correction corrects the error caused by inconsistent temperatures at the remote pressure measurement point. The liquid level / flow measurement value sent to the controller has completed temperature correction, improving the accuracy and facilitating the installation and maintenance of the field instrument; at the same time, it can be conveniently replaced on-site without the need for additional drilling and installation of auxiliary instruments or other equipment, facilitating engineering construction and subsequent maintenance, and not affecting the existing on-site installation method and wiring, and can realize in-situ remote temperature and pressure compensation, improving the measurement accuracy of on-site pressure / differential pressure and derived variables such as liquid level / flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of the overall structure of the remote pressure instrument of the present invention;

[0029] Figure 2 is a front view structural schematic diagram of the remote flange structure of the present invention;

[0030] Figure 3 is a schematic diagram of the internal structure of the remote flange structure of the present invention;

[0031] Figure 4 is of the present invention Figure 3 an enlarged structural schematic diagram of part A in;

[0032] Figure 5 is a schematic diagram of the terminal cross-sectional structure of the present invention;

[0033] Figure 6 is a connection block diagram of the overall structure of the pressure instrument of the present invention;

[0034] Figure 7 is a schematic diagram of the software flow of the internal MCU of the pressure instrument of the present invention;

[0035] Figure 8 is a schematic diagram of the multi-parameter digital base sensor of the present invention.

[0036] In the figure: Process structure to be measured - 1, Remote flange structure - 2, Base sensor unit - 3, Controller - 4, Pressure gauge body - 5, Remote flange - 21, Temperature sensor - 22, Long cable - 23, Connecting sleeve - 24, Oil filling pipe - 25, Threaded groove - 26, Terminal - 261, Positioning groove - 27, Connecting groove - 271. Specific implementation mode

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] Embodiment 1

[0039] Please refer to Figures 1 - 7 , A pressure gauge for realizing remote temperature difference correction, including a remote flange structure 2, a base sensor unit 3, and a pressure gauge body 5. The remote flange structure 2 is installed on both sides of the process structure to be measured 1. Both ends of the base sensor 3 are respectively connected to the middle parts of the two groups of remote flange structures 2. After the measurement signal of the base sensor unit 3 is converted and calculated by the pressure gauge body 5, a data connection is established with the controller 4; The remote flange structure 2 includes a remote flange 21, a temperature sensor 22, a long cable 23, a connecting sleeve 24, and an oil filling pipe 25. The remote flange 21 is fixed to the right end of the process structure to be measured 1. The temperature sensor 22 is connected to the pressure gauge body 5 by a long cable 23. The oil filling pipe 25 is inserted into the left end of the connecting sleeve 24.

[0040] In some embodiments, a threaded groove 26 is provided at the upper left end of the remote flange 21. The temperature sensor 22 is in threaded fit with the inner thread of the threaded groove 26, which is convenient for fixing and positioning the temperature sensor 22. A positioning groove 27 starts from the middle of the left end of the remote flange 21. The connecting sleeve 24 is embedded in the inner side of the positioning groove 27, which is convenient for installing and fixing the connecting sleeve 24. A connecting groove 271 is provided at the right end of the positioning groove 27. The oil filling pipe 25 passes through the connecting groove 271 on the positioning groove 27 and penetrates into the interior of the process structure to be measured 1, and the oil filling pipe 25 is connected to the base sensor unit 3. A terminal 261 is provided at the inner right end of the threaded groove 26. The right end of the temperature sensor 22 is in contact with the terminal 261. The MCU inside the pressure gauge body 5 uses STM32G030 and integrates a 12-bit ADC converter inside, which can realize signal sampling of 2 external temperature sensors 22. The MCU inside the pressure gauge body 5 is specific.

[0041] In this application, a 24-bit ADC is externally placed on the pressure gauge body 5, and the AD7799 is used for the 24-bit ADC to ensure the measurement accuracy and sampling rate of the pressure sensor of the process structure to be measured. The circuit output part of the pressure gauge body 5 adopts the method of AD5421 + AD5700 to output a 4-20 mA superimposed HART digital signal. The temperature sensor 22 uses an armored three-wire pt100 and is installed and fixed in a threaded manner with the threaded groove 26; the three lead-out wires of the pt100 are connected to the on-site pressure gauge through a shielded oil-filled tube.

[0042] In summary, the present invention pre-buries the temperature sensor 22 on the remote flange 21 and transmits the temperature measurement electrical signal to the pressure gauge body 5 through the long cable 23 to realize the measurement of the ambient temperature of the remote pressure sampling point. Furthermore, through the MCU microprocessor software in the gauge body, the compensation and correction of the temperature difference are realized;

[0043] Secondly, it is the electrical signal processing inside the pressure gauge body 5. The base sensor unit 3 usually includes a pressure / differential pressure sensor and an attached temperature-sensitive element, and this temperature-sensitive element performs temperature compensation for the pressure / differential pressure sensor; the output signals of the pressure / differential pressure sensor and the internal temperature sensor are usually sampled and converted through the ADC externally placed by the MCU and sent into the microprocessor for real-time calculation;

[0044] For the newly added remote temperature sensor 22 of the present invention, after being sent into the gauge body, the ADC integrated in the MCU will be used for sampling and conversion. On the one hand, because the externally placed ADC is usually integrated with the base sensor unit 3, if it is still desired to use the externally placed ADC, additional wiring is required inside the gauge, which brings unreliability; on the other hand, the measurement accuracy and sampling rate requirements for external temperature are generally relatively low, and the 12-bit ADC integrated inside the MCU can usually meet the usage requirements, and the lead wires and circuit structure are relatively easy to implement;

[0045] After respectively completing the pressure / differential pressure measurement and compensation of the base sensor unit 3, the remote temperature is measured, and then the temperature difference is corrected to obtain an accurate pressure / differential pressure measurement value. The derivative measurement value is calculated through the liquid level or flow formula, and finally becomes a standard 4-20 mA or 1-5V superimposed HART digital carrier through DA conversion and is sent to the controller system.

[0046] Embodiment 2

[0047] Please refer to Figure 8, a pressure instrument for realizing remote temperature difference correction. The temperature sensor 22 uses an NTC thermistor ERT-J1VG103FA and is mounted inside the remote flange diaphragm in a surface mount manner. It is connected to the inside of the field instrument by a shielded wire. The difference from Embodiment 1 is that in Embodiment 2, the base sensor unit 3 includes a differential pressure sensor, a pressure sensor, and an internal temperature sensor, and integrates an independent ADC and a front-end signal processing and calculation unit to realize multi-variable measurement and digital value output of the base sensor.

[0048] In this application, the output of the multi-parameter sensor is directly connected to the main board through UART to read the measured pressure, differential pressure, and internal temperature values; and the ADC built in the main board MCU samples and converts to obtain the remote temperature value, thereby realizing remote temperature difference correction.

[0049] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pressure instrument for realizing remote temperature difference correction, characterized in that: It includes a remote flange structure (2), a base sensor unit (3), and a pressure gauge body (5). The remote flange structure (2) is installed on both sides of the process structure to be measured (1). Both ends of the base sensor (3) are respectively connected to the middle parts of two groups of the remote flange structures (2). After the measurement signal of the base sensor unit (3) is converted and calculated by the pressure gauge body (5), a data connection is established with the controller (4). The remote flange structure (2) includes a remote flange (21), a temperature sensor (22), a long cable (23), a connecting sleeve (24), and an oil filling pipe (25). The remote flange (21) is fixed to the right end of the process structure to be measured (1). The temperature sensor (22) is connected to the pressure gauge body (5) by the long cable (23). The oil filling pipe (25) is inserted into the left end of the connecting sleeve (24).

2. The pressure instrument for realizing remote temperature difference correction according to claim 1, characterized in that: A threaded groove (26) is provided at the upper left end of the remote flange (21), and the temperature sensor (22) is in threaded fit with the inner thread of the threaded groove (26).

3. The pressure instrument for realizing remote temperature difference correction according to claim 1, characterized in that: A positioning groove (27) starts from the middle of the left end of the remote flange (21), and the connecting sleeve (24) is embedded in the inner side of the positioning groove (27).

4. The pressure instrument for realizing remote temperature difference correction according to claim 3, characterized in that: A connecting groove (271) is provided at the right end of the positioning groove (27). The oil filling pipe (25) passes through the connecting groove (271) on the positioning groove (27) and penetrates into the interior of the process structure to be measured (1), and the oil filling pipe (25) is connected to the base sensor unit (3).

5. The pressure gauge for realizing remote temperature difference correction according to claim 2, wherein: A terminal (261) is provided at the right end of the inner side of the threaded groove (26), and the right end of the temperature sensor (22) is in contact with the terminal (261).

6. The pressure instrument for realizing remote temperature difference correction according to claim 1, characterized in that: The MCU inside the pressure gauge body (5) uses STM32G030 and integrates a 12-bit ADC converter inside.

7. A pressure gauge for realizing remote temperature difference correction according to claim 1, characterized in that: The specific working steps of the MCU inside the pressure gauge body (5) are as follows: Step S1: The MCU is initialized; Step S2: The MCU completes the pressure / differential pressure sampling and calculation of the base sensor unit (3); Step S3: Subsequently, the temperature sampling and compensation calculation of the process structure to be measured are performed; Step S4: Next, the remote temperature sampling is performed; Step S5: The remote temperature difference is corrected to obtain an accurate pressure / differential pressure measurement value; Step S6: The derivative measurement value is calculated through the liquid level or flow formula, and finally, it is converted into a standard 4 - 20mA or 1 - 5V superimposed HART digital carrier through DA conversion and sent to the controller system.

8. A pressure instrument for realizing remote temperature difference correction according to claim 1, characterized in that: The pressure gauge body (5) is externally provided with a 24-bit ADC, and the 24-bit ADC uses AD7799. The circuit output part of the pressure gauge body (5) adopts the method of AD5421 + AD5700 to output a 4 - 20mA superimposed HART digital signal.

9. A pressure instrument for realizing remote temperature difference correction according to claim 1, characterized in that: The temperature sensor (22) uses an armored three-wire pt100, and the base sensor unit (3) includes a pressure / differential pressure sensor and an attached temperature-sensitive element.

10. A pressure instrument for realizing remote temperature difference correction according to claim 1, characterized in that: The temperature sensor (22) uses an NTC thermistor (ERT-J1VG103FA). The base sensor unit (3) includes a differential pressure sensor, a pressure sensor, and an internal temperature sensor, and integrates an independent ADC as well as a front-end signal processing and calculation unit.

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