Coplanar differential pressure transmitter

Abstract

The invention discloses a coplanar differential pressure transmitter which is small in overall size, high in response speed and capable of conducting temperature compensation to ensure that the accuracy of a measurement result is high. The system comprises two groups of sensors; two groups of signal conditioning circuit boards; the metal shell is a sensor placement shell, two groups of mounting positioning grooves are formed in the bottom of the metal shell, and the mounting positioning grooves are used for placing sensors; an industrial housing; the digital display meter head comprises a conversion circuit board and a display screen; the sensor is fixedly installed in the installation positioning groove, the diaphragm end of the sensor is communicated with the atmosphere, the inner end of the sensor is connected with a signal conditioning circuit board, the signal conditioning circuit board has a temperature compensation function, and the signal conditioning circuit board converts weak voltage signals from the sensor into standard digital signals and carries out temperature compensation on the sensor. The top of the sensor external housing is fixedly connected with an industrial housing, and an inner cavity of the industrial housing is provided with a digital display meter.

Description

Technical Field

[0001] The invention relates to the technical field of pressure measurement, in particular to a coplanar differential pressure transmitter. Background Art

[0002] A differential pressure transmitter is a device used to measure the pressure difference in a fluid. It is widely used in industrial control, measurement, pressure monitoring and other fields. Traditional differential pressure transmitters are suitable for various industrial applications and environmental conditions, including high temperature, high pressure and corrosive environment. Due to its simple design and structure, traditional differential pressure transmitters usually have low maintenance costs. In general, differential pressure transmitters are an important industrial measurement equipment with a wide range of uses, and technological development and improvement will bring greater benefits and convenience to industrial production.

[0003] There are many types of differential pressure transmitters on the market. Usually, differential pressure transmitters have connectors for connecting to pipes or piping systems. These connectors are usually located at both ends or sides of the metal shell and have standard threaded interfaces for safe and reliable connection with the piping system. In addition, most of the differential pressure transmitters on the market do not have temperature compensation, and the output of the sensor is greatly affected by temperature changes. The test results are not ideal in harsh environments.

[0004] In summary, traditional differential pressure transmitters are troublesome to install, require a large space, and are greatly affected by temperature changes, resulting in low measurement accuracy. Summary of the invention

[0005] In view of the above problems, the present invention provides a coplanar differential pressure transmitter, which has a small overall volume, a fast response speed and can perform temperature compensation to ensure high accuracy of measurement results.

[0006] A coplanar differential pressure transmitter, characterized in that it comprises:

[0007] Two sets of sensors;

[0008] Two sets of signal conditioning circuit boards;

[0009] A metal shell, which is a sensor placement shell, and has two sets of installation positioning grooves at the bottom, and the installation positioning grooves are used to place the sensor;

[0010] Industrial enclosures;

[0011] and a digital display head, which includes a conversion circuit board and a display screen;

[0012] The sensor is fixed in the installation positioning groove, and the diaphragm end of the sensor is connected to the atmosphere. The inner end of the sensor is connected to the signal conditioning circuit board, and the signal conditioning circuit board is provided with a temperature compensation function. The signal conditioning circuit board converts the weak voltage signal from the sensor into a standard digital signal and performs temperature compensation on the sensor. The top of the sensor external shell is fixedly connected to the industrial shell, and the inner cavity of the industrial shell is provided with the digital display head. The two groups of the signal conditioning circuit boards are electrically connected to the conversion circuit board respectively, and the display screen is used to display the signal obtained by the conversion circuit board after processing and analysis.

[0013] It is further characterized by:

[0014] The sensor is a silicon piezoresistive pressure sensor; the silicon piezoresistive pressure sensor is used to output a weak voltage signal that is linearly proportional to the pressure through a Wheatstone bridge.

[0015] The sensor includes a diaphragm welding ring, a corrugated diaphragm, a ceramic seat, a pressure chip, a bonding wire, a metal sintering seat, pins, and a vent hole. The metal sintering seat includes a sensor groove for placing a signal conditioning circuit board and a placement cavity. The corrugated diaphragm, the pressure chip, and the ceramic seat are placed in the placement cavity.

[0016] The pressure chip is placed in the placement cavity and bonded to the metal sintering seat, and then the pressure chip is bonded to the ceramic seat to prevent the bonding gold wire from collapsing. After bonding and curing, the gold wire is bonded to complete the bonding of the pressure chip and the pin; then the bonded metal sintering seat is combined with the corrugated diaphragm and the diaphragm welding ring, and the welding is performed by tightening the mold to align the welding surface of the core body, so that the diaphragm welding ring and the metal sintering seat are reliably assembled, the pin of the sensor is docked with the signal conditioning circuit board, and the positioning surface of the signal conditioning circuit board is set to fit the groove, the pin of the signal conditioning circuit board is welded, and the wire is welded at the pin and coated with glue for protection. One end of the pin is connected to the pressure chip through the bonding gold wire, and the other end is electrically connected to the signal conditioning circuit board for storing the compensated temperature parameters;

[0017] The vent of the sensor is connected to the atmosphere, and the sensor compares the pressure of the external gas with the pressure of the atmosphere connected to the vent to obtain a pressure difference, and then converts the pressure difference into a weak voltage signal;

[0018] The signal conditioning circuit board is calibrated and temperature compensated through the host computer system, so that the signal conditioning circuit board has a temperature compensation function;

[0019] The metal shell is used to fix and protect the sensor and signal conditioning circuit board inside it. The metal shell includes a shell base, a shell top cover, and connecting studs. The bottom of the shell base is provided with two sets of mounting positioning grooves. The upper end of the shell base is attached to the lower end surface of the shell top cover and is locked and connected by connecting studs.

[0020] The outer circumference of the outer cover of the housing is provided with a standard external installation thread, which is suitable for installing industrial housings of different models. The four corners of the bottom of the housing base are provided with fixed thread holes for adapting to the fixing mechanism;

[0021] The end surface of the housing base facing the housing top cover is provided with a sealing gasket groove, a sealing gasket is placed inside the sealing gasket groove, and the sealing gasket is used for sealing connection between the housing base and the housing top cover;

[0022] The metal shell further comprises a wire hole, which is located in the top cover of the shell and is used for leading out the sensor signal line;

[0023] The sensor is connected to the installation positioning groove by welding, and the welding surface of the installation positioning groove is located at the bottom of the installation positioning groove, which is used to weld the sensor to the housing base;

[0024] The industrial housing comprises a main housing, a front cover, a rear cover and a sealing ring;

[0025] The digital display head is composed of a data processing circuit board, a plastic protective shell, and a liquid crystal display screen. The data processing circuit board is electrically connected to the calibrated and compensated sensor through a wire. The data collected by the two sensors are processed and the measurement results are displayed on the liquid crystal display screen. The plastic protective shell is used to protect the data processing circuit board from external wear.

[0026] After adopting the present invention, two sensors are coplanarly arranged in corresponding independent installation positioning grooves at the bottom of the metal shell, the diaphragm end of the sensor is connected to the atmosphere, and the inner end of each group of sensors is independently connected to a corresponding signal conditioning circuit board, and the signal conditioning circuit board is provided with a temperature compensation function. The signal conditioning circuit board converts the weak voltage signal from the sensor into a standard digital signal, and performs temperature compensation on the sensor, thereby improving the measurement accuracy of the sensor after temperature compensation. In addition, an industrial shell is designed on the top, which is made of a sturdy and durable material with good protective performance and can withstand harsh industrial environmental conditions; the problems of non-coplanar design of the existing differential pressure transmitter, excessive volume, slow response speed and great influence of temperature changes, resulting in low measurement accuracy, are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the three-dimensional structure of a specific embodiment of the present invention;

[0028] Figure 2 is a cross-sectional view of a sensor applicable to the present invention;

[0029] Figure 3 It is a schematic diagram of the cross-sectional structure of a metal shell corresponding to a specific embodiment of the present invention;

[0030] Figure 4 It is a schematic diagram of the cross-sectional structure of the metal housing and the sensor assembly according to a specific embodiment of the present invention;

[0031] Figure 5 A schematic diagram of the operation of a signal conditioning circuit board according to a specific embodiment of the present invention;

[0032] Figure 6 It is a structural schematic diagram of an industrial housing according to a specific embodiment of the present invention;

[0033] Figure 7 It is a structural schematic diagram of a digital display head according to a specific embodiment of the present invention;

[0034] The names corresponding to the serial numbers in the figure are as follows:

[0035] 1 sensor, 11 diaphragm welding ring, 111 welding surface, 12 corrugated diaphragm, 13 ceramic seat, 14 pressure chip, 15 bonding wire, 16 metal sintering seat, 161 pin, 162 groove, 163 vent hole, 164 core welding surface, 17 wire;

[0036] 2 signal conditioning circuit board;

[0037] 3 metal shell, 31 shell base, 311 installation positioning groove, 312 welding surface, 313 sealing gasket groove, 314 fixing threaded hole, 32 shell top cover, 321 installation external thread, 322 connecting threaded hole, 33 sealing gasket, 34 O-type sealing ring, 35 connecting stud;

[0038] 4 industrial housing, 41 main housing, 42 rear cover, 43 front cover, 44 sealing ring;

[0039] 5. digital display head, 51. data processing circuit board, 52. plastic protective shell, 53. liquid crystal display screen. DETAILED DESCRIPTION

[0040] A coplanar differential pressure transmitter, see Figure 1-Figure 7 , which includes: two sets of sensors 1, two signal conditioning circuit boards 2, a metal shell 3, an industrial shell 4, and a digital display head 5.

[0041] Among them, a bottom surface of the metal shell 3 is provided with two installation positioning grooves 311, and each installation positioning groove 311 is used for welding a sensor 1;

[0042] The diaphragm end of the sensor 1 is connected to the atmosphere; the vent 163 of the sensor 1 is also connected to the atmosphere. The sensor 1 is used to compare the pressure from the external gas with the pressure of the atmosphere connected to the vent 163 to obtain the pressure difference, and then convert the pressure difference into a weak voltage signal; the pin 161 at the groove of each sensor 1 is electrically connected to the signal conditioning circuit board 2; after the different gas pressures measured by the two sensors 1 are converted into weak voltage signals, the conditioned and compensated signals are transmitted to the digital display head 5 through the wire 17 through two different signal conditioning circuit boards 2, and the data processing circuit board 51 displays the two signals on the LCD screen 53 after calculation.

[0043] In addition to the commonly used signal amplification and conversion, the signal conditioning circuit board 2 also adds a temperature compensation function, that is, the signal conditioning circuit board 2 amplifies the weak voltage signal of the sensor 1 and converts it into a standard signal. It also performs temperature compensation on the sensor output to eliminate the influence of temperature changes on the measurement results and improve the accuracy and stability of the measurement.

[0044] The metal shell 3 provided in the embodiment of the present invention is composed of a shell base 31 and a shell top cover 32. Specifically, the metal shell 3 is mainly used to fix and protect the sensor 1 and the signal conditioning circuit board 2 inside it; a standard mounting external thread 321 is provided at the shell top cover 32, and different types of industrial shells can be installed; the shell base 31 is provided with a fixed threaded hole 314, which can be replaced according to different mounting threaded hole diameters; the shell base 31 is also provided with a sealing gasket groove 313, and a sealing gasket 33 is placed inside the sealing gasket groove 313 for sealing the shell base and the shell top cover.

[0045] like Figure 3 As shown, the installation positioning groove 311 is located in the housing base 31, and the installation positioning groove 311 is used to install the welding sensor 1; the signal conditioning circuit board 2 is arranged in the sensor groove 162. In actual application, the sensor 1 is welded and sealed in the housing base 31 through the housing base welding surface 312.

[0046] In order to seal the interior of the metal shell 3 and the pipeline to be measured, a sealing gasket groove 313 is further provided between the shell base 31 and the pipeline to be set, that is, the shell base 31 and the shell top cover 32 can be sealed by the sealing gasket 33 set in the sealing gasket groove 313.

[0047] The sensor 1 and the metal housing 3 are welded by laser, and the housing top cover 32 is assembled and sealed. At the same time, a special compensation algorithm is added to the signal conditioning circuit board 2 to achieve the coplanar design, low temperature drift, high precision and simple production process of the differential pressure transmitter, which can solve the problem that the existing differential pressure transmitter is not coplanar in design and is greatly affected by temperature changes, resulting in low measurement accuracy.

[0048] like Figure 2 As shown, the sensor 1 provided by the embodiment of the present invention mainly outputs a voltage signal linearly proportional to the pressure from the measured pressure through a Wheatstone bridge. The sensor 1 is composed of a diaphragm welding ring 11, a welding surface 111, a corrugated diaphragm 12, a ceramic seat 13, a pressure chip 14, a bonding wire 15, a metal sintering seat 16, a pin 161, a sensor groove 162, a vent 163, and a core welding surface 164. Among them, the pressure of the measured gas is transmitted to the pressure chip 14 by squeezing the corrugated diaphragm 12, and the Wheatstone bridge on the pressure chip 14 outputs a voltage signal linearly proportional to the pressure through the change of the output resistance of the piezoresistive effect, and the voltage signal is transmitted to the signal conditioning circuit board 2 through the bonding wire 15 and the pin 161. The signal conditioning circuit board 2 is connected to the sensor 1 through the pin 161 to realize the transmission of the voltage signal measured by the sensor. The sensor 1 is welded and positioned with the mounting fixing groove 311 by laser welding technology, and the welding surface 111 is welded with the welding surface 312 of the housing base; it adopts very precise welding position control and extremely small heat-affected zone to minimize the impact on the pressure chip 14.

[0049] It should be noted that the sensor 1 provided in the embodiment of the present invention is preferably a silicon piezoresistive pressure sensor.

[0050] See Figure 5 The signal conditioning circuit board 2 provided in the embodiment of the present invention has the function of supplying power to the transmitter, amplifying and transforming the weak voltage signal output by the sensor 1, and making temperature compensation so that the sensor 1 is less affected by the temperature change output, and can output a high-precision standard signal. In the embodiment of the present invention, the MCU in the conversion circuit board 2 stores the compensated temperature parameters, while taking into account the integrated wide voltage DC 12V~30V power supply, high-precision 24-bit AD conversion and reverse connection protection and other functions.

[0051] The signal conditioning circuit board 2 is electrically connected to the sensor 1 and is used to store parameters after calibration and temperature compensation. One end of the signal conditioning circuit board 2 is electrically connected to the sensor 1 , and the other end is electrically connected to the data processing circuit board 51 .

[0052] like Figure 6As shown, the industrial housing 4 is composed of a main housing 41, a rear cover 42, a front cover 43 and two sealing rings 44. The function of the industrial housing 4 is to protect the internal electronic components from various adverse conditions in the industrial environment. A sealing ring 44 is provided at the connection between the front cover 43, the rear cover 42 and the main housing 41. The sealing ring 44 can play a sealing role, prevent dust from entering and resist the intrusion of low-pressure water jets from all directions, and ensure that the equipment can work safely in a humid or dusty environment. At the same time, the industrial housing makes the product look more professional and beautiful. In addition, the housing usually has brand logos, model specifications and other information for easy identification and management.

[0053] like Figure 7 As shown, the digital display head 5 is composed of a data processing circuit board 51, a plastic protective shell 52, and a liquid crystal display screen 53. The data processing circuit board 51 is electrically connected to the calibrated and compensated sensor 2 through a wire 17, and is used to process the data collected by the two sensors and display the measurement results through the liquid crystal display screen 53. The plastic protective shell 52 is used to protect the data processing circuit board 51 from external wear.

[0054] In order to more clearly introduce the coplanar differential pressure transmitter provided by the embodiment of the present invention, the preparation method of the coplanar differential pressure transmitter provided by the embodiment of the present invention is briefly introduced below.

[0055] The first step is to prepare the sensor 1, specifically, Figure 2 As shown, the metal sintering seat 16 in the raw materials is first cleaned and dried, the pressure chip 14 is bonded to the metal sintering seat 16, and then the ceramic seat 13 for protecting the pressure chip 14 and preventing the bonding wire 15 from collapsing is bonded, and the bonding wire 15 is bonded after bonding and curing, so as to complete the bonding of the pressure chip 14 and the pin 161; secondly, the bonded metal sintering seat 16, the corrugated diaphragm 12, and the diaphragm welding ring 11 are assembled, and the welding is performed by tightening the mold to align with the core welding surface 164; finally, the sensor 1 is cleaned, placed in a high-temperature oven for storage and stress relief, and then naturally cooled to room temperature;

[0056] The second step is to connect the pin 161 of the sensor 1 with the signal conditioning circuit board 2, and press the signal conditioning circuit board 2 and the groove surface of the sensor 1 to be flush, solder the pin 161 to the circuit board 2, and solder the wire 17 at the pin 161 and apply glue for protection, and perform calibration and temperature compensation through the host computer system. The specific compensation algorithm will be described below;

[0057] The third step is to assemble the prepared sensor 2 to Figure 3The metal housing 31 shown is specifically assembled into the sensor installation positioning groove 311 of the housing base, ensuring that the surfaces of the two parts are flush and free of debris, and the welding surface 312 of the connection between the two parts is welded by a laser welding machine, and the welded assembly is placed vertically, and the other sensor performs the same operation;

[0058] Step 4: Assemble the prepared housing base 31 and housing top cover 32. Specifically, put the sealing gasket 33 into the sealing gasket groove 311, align the housing top cover 32 on the top of the housing base 31, and assemble it by connecting the studs 35 and the mounting external threads 321;

[0059] The fifth step is to install the metal shell 3 and the industrial shell 4 by installing the external thread 321; at the same time, weld the digital display head 5 and the output wire 17 of the sensor 1; and fix the digital display head 5 and the industrial shell 4 by threaded assembly to obtain a complete coplanar differential pressure transmitter.

[0060] The signal conditioning circuit board 2 provided in the embodiment of the present invention can provide temperature compensation for the sensor 1, which is verified by the following experiments:

[0061] Specifically, the sensor provided by the embodiment of the present invention is fixed in a pressurized fixture, and is placed in a high and low temperature test box after being connected to a pressure gauge to ensure the thermal insulation of the high and low temperature test box. The temperature of the test box is set to three different temperature values, namely 0°C, 25°C, and 50°C. Each temperature value is stable for 2 hours or more. After the temperature is stable, three different pressure loads are applied to the pressure transmitter, which are 10%, 50%, and 90% of the sensor range, respectively. The output signal end of the pressure transmitter is connected to the IIC interface to the computer calibration software, and the temperature AD values ​​and three pressure AD values ​​at three different temperatures are collected in turn. After the data is obtained, the computer compensation software calculates and writes the result coefficient into the MCU associated register on the signal conditioning circuit board. The software compensation calculation principle is as follows:

[0062] When the working environment is fixed, the sensor AD input and AD output always satisfy formula (1):

[0063]

[0064] When the sensor works in different ambient temperatures, the AD input and AD can be expressed by a one-dimensional polynomial equation as shown in formula (2):

[0065]

[0066] Where "AD output" is the ideal AD value of the sensor under different temperature environments. "AD input" is the AD value actually collected by the sensor. "β0, β1, β2..." are the coefficients of each expression.

[0067] By using a large amount of data collected in practice and solving the equations through software, we can get the values ​​of each coefficient, thereby obtaining the sensor output equation at different temperatures.

[0068] Because the coefficients β obtained by solving formula 2 will also change with the change of temperature, the coefficient β and temperature t satisfy the following relationship:

[0069] β=A+Bt+Ct 2 +......+Dt n (Formula 3)

[0070] The coefficients can also be expressed as one-dimensional polynomial equations:

[0071]

[0072] The coefficients in Formula 4 can be solved using the coefficient β calculated from Formula 1 and the known temperature.

[0073] The mathematical models of Formula 2 and Formula 4 are stored in the upper computer software, and the mathematical model of Formula 1 is stored in the conversion circuit board MCU. A large amount of data is collected through the small-size pressure transmitter, which is connected to the computer software through the IIC interface. The compensation software uses these data to calculate the coefficients of Formula 2 and Formula 4 and writes them into the conversion circuit board MCU. The sensor will obtain a definite formula (Formula 1), and the compensated output AD value can be simply calculated through Formula 1.

[0074] Calibration compensation is achieved through the compensation software of the host computer. Compared with the uncompensated sensor, the maximum error of the compensation result is reduced from 3% to 4% to less than 0.5% within the compensated temperature range, which greatly reduces the influence of temperature on the sensor.

[0075] In summary, an embodiment of the present invention provides a coplanar differential pressure transmitter, including: a metal shell, one end of which is provided with a sensor installation positioning hole, and two silicon piezoresistive sensors are arranged in the base of the shell, which are used to convert the pressure of the external gas into a weak voltage signal; one end of the sensor groove is electrically connected to a signal conditioning circuit board, and the signal conditioning circuit board is used to convert the weak voltage signal from the sensor into a standard digital signal. In addition to the commonly used amplification and conversion, the signal conditioning circuit board has an added temperature compensation function to reduce the influence of temperature on the sensor; there is a digital display head inside the industrial shell, and the display screen of the digital display head is electrically connected to the conversion circuit board, and the output signal is processed and analyzed and displayed. The industrial shell protects the internal machinery, electronics or other equipment from the influence of the external environment, thereby solving the problem that the existing differential pressure transmitter is non-coplanar in design, large in size, slow in response, and greatly affected by temperature changes, resulting in low accuracy of measurement results.

[0076] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0077] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A coplanar differential pressure transmitter, characterized in that: It includes: Two sets of sensors; Two sets of signal conditioning circuit boards; A metal shell, which is a sensor placement shell, and has two sets of installation positioning grooves at the bottom, and the installation positioning grooves are used to place the sensor; Industrial enclosures; and a digital display head, which includes a conversion circuit board and a display screen; The sensor is fixed in the installation positioning groove, and the diaphragm end of the sensor is connected to the atmosphere. The inner end of the sensor is connected to the signal conditioning circuit board, and the signal conditioning circuit board is provided with a temperature compensation function. The signal conditioning circuit board converts the weak voltage signal from the sensor into a standard digital signal and performs temperature compensation on the sensor. The top of the sensor external shell is fixedly connected to the industrial shell, and the inner cavity of the industrial shell is provided with the digital display head. The two groups of the signal conditioning circuit boards are electrically connected to the conversion circuit board respectively, and the display screen is used to display the signal obtained by the conversion circuit board after processing and analysis.

2. A coplanar differential pressure transmitter according to claim 1, characterized in that: The sensor is a silicon piezoresistive pressure sensor; the silicon piezoresistive pressure sensor is used to output a weak voltage signal that is linearly proportional to the pressure through a Wheatstone bridge.

3. A coplanar differential pressure transmitter according to claim 1, characterized in that: The sensor includes a diaphragm welding ring, a corrugated diaphragm, a ceramic seat, a pressure chip, a bonding wire, a metal sintered seat, pins, and a vent. The metal sintered seat includes a sensor groove for placing a signal conditioning circuit board and a placement cavity, in which the corrugated diaphragm, the pressure chip, and the ceramic seat are placed.

4. A coplanar differential pressure transmitter according to claim 3, characterized in that: The pressure chip is placed in the placement cavity and bonded to the metal sintering seat, and then the pressure chip is bonded to the ceramic seat to prevent the bonding gold wire from collapsing. After bonding and curing, the gold wire is bonded to complete the bonding of the pressure chip and the pin; then the bonded metal sintering seat is combined with the corrugated diaphragm and the diaphragm welding ring, and the welding is performed by tightening the mold to align the welding surface of the core body, so that the diaphragm welding ring and the metal sintering seat are reliably assembled, the pin of the sensor is docked with the signal conditioning circuit board, and the positioning surface of the signal conditioning circuit board is set to fit the groove, the pin of the signal conditioning circuit board is welded, and the wire is welded at the pin and coated with glue for protection. One end of the pin is connected to the pressure chip through the bonding gold wire, and the other end is electrically connected to the signal conditioning circuit board for storing the compensated temperature parameters; The vent hole of the sensor is connected to the atmosphere. The sensor compares the pressure from the external gas with the pressure of the atmosphere connected to the vent hole to obtain a pressure difference, and then converts the pressure difference into a weak voltage signal.

5. The coplanar differential pressure transmitter according to claim 1, characterized in that: The metal shell is used to fix and protect the sensor and signal conditioning circuit board inside it. The metal shell includes a shell base, a shell top cover, and connecting studs. Two groups of mounting positioning grooves are provided at the bottom of the shell base. The upper end of the shell base fits the lower end surface of the shell top cover and is locked and connected by connecting studs.

6. A coplanar differential pressure transmitter according to claim 1, characterized in that: The outer circumference of the outer cover of the housing is provided with a standard external installation thread, which is suitable for installing industrial housings of different models. The four corners of the bottom of the housing base are provided with fixed thread holes for adapting to the fixing mechanism.

7. The coplanar differential pressure transmitter according to claim 1, characterized in that: The outer circumference of the outer cover of the housing is provided with a standard external installation thread, which is suitable for installing industrial housings of different models. The four corners of the bottom of the housing base are provided with fixed thread holes for adapting to the fixing mechanism.

8. A coplanar differential pressure transmitter according to claim 7, characterized in that: The end surface of the shell base facing the shell top cover is provided with a sealing gasket groove, a sealing gasket is placed inside the sealing gasket groove, and the sealing gasket is used for sealing connection between the shell base and the shell top cover.

9. The coplanar differential pressure transmitter according to claim 1, characterized in that: The industrial housing comprises a main housing, a front cover, a rear cover and a sealing ring.

10. The coplanar differential pressure transmitter according to claim 1, characterized in that: The digital display head is composed of a data processing circuit board, a plastic protective shell, and a liquid crystal display screen. The data processing circuit board is electrically connected to the calibrated and compensated sensor through a wire. The data collected by the two sensors are processed and the measurement results are displayed on the liquid crystal display screen. The plastic protective shell is used to protect the data processing circuit board from external wear.

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