A 250mpa liquid medium automatic standard pressure generator

Abstract

The application belongs to the field of detection and calibration of pressure instruments, and particularly relates to a 250MPa liquid medium automatic standard pressure generator, which comprises a pressure generating unit for outputting a target pressure to a detected pressure instrument; a sensor unit in communication connection with the pressure generating unit and used for acquiring an execution state signal of the pressure generating unit; and a control processing unit in communication connection with the pressure generating unit and the sensor unit, and used for acquiring a sensor unit signal and processing a feedback to the pressure generating unit. The 250MPa liquid medium automatic standard pressure generator can not only accelerate the pressure control speed of a liquid medium standard pressure generator, but also improve the pressure control accuracy of the liquid medium standard pressure generator, and can realize an automatic pressure control function. Compared with existing 250MPa liquid medium standard pressure generator products on the market, the control performance of the 250MPa liquid medium automatic standard pressure generator product is greatly improved.

Description

Technical Field

[0001] This application belongs to the field of pressure instrument testing and calibration, specifically relating to a 250MPa automatic standard pressure generator for liquid media. Background Technology

[0002] Existing 250MPa liquid medium standard pressure generators on the market typically employ manual pressurization mechanisms. Manual pressurization requires human operation, and reaching 250MPa pressure is time-consuming and labor-intensive, especially when approaching 250MPa, where the increased reaction force of the high-pressure liquid necessitates significant effort with each pressurization. Even in rare cases where electric drive technology is used, the hydraulic piston mechanism in the pressurization process presents challenges. A small piston rod cross-sectional area results in slow liquid compression, leading to slow pressurization; conversely, a large piston rod cross-sectional area increases the volume change of liquid in a single compression, reducing pressure control precision. Furthermore, these products use ordinary motors as electric actuators, whose poor control precision further degrades the pressure generator's control performance. Such a pressure-generating mechanism inherently cannot achieve fast pressure control speeds or high pressure control precision, resulting in long pressure control times and low pressure control accuracy for existing 250MPa liquid medium pressure generators on the market. Summary of the Invention

[0003] The purpose of this application is to provide a 250MPa automatic standard pressure generator for liquid media with fast pressure control speed, good output pressure stability, and high degree of automation.

[0004] The technical solution adopted in this application is as follows: An automatic standard pressure generator for liquid media of 250MPa, comprising: The pressure generating unit is used to output standard pressure to the pressure gauge being tested; The sensor unit is communicatively connected to the pressure generating unit and is used to acquire the execution status signal of the pressure generating unit; The control processing unit is communicatively connected to the pressure generating unit and the sensor unit, and is used to acquire signals from the sensor unit, process them, and feed them back to the pressure generating unit.

[0005] By adopting the above technical solution, manual pressurization is no longer required, and the required standard pressure value can be quickly output to the pressure gauge being tested.

[0006] Furthermore, the pressure generating unit includes a sealed hydraulic container and a pressurizing mechanism for changing the output pressure of the sealed hydraulic container; the pressurizing mechanism includes two sets of hydraulic control mechanisms with different output pressures, the input ends of the two sets of hydraulic control mechanisms are respectively connected to the control processing unit, and the output ends of the two sets of hydraulic control mechanisms are respectively connected to the sealed hydraulic container.

[0007] By adopting the above technical solution and utilizing two sets of hydraulic control mechanisms with different output pressures, the generator can be quickly switched during different pressurization periods.

[0008] Furthermore, the pressurization mechanism includes a hydraulic control mechanism one for controlling the rate of change of the output pressure of the sealed hydraulic container and a hydraulic control mechanism two for controlling the accuracy of the change of the output pressure of the sealed hydraulic container.

[0009] By adopting the above technical solutions, both the pressure control speed and the pressure control accuracy can be improved simultaneously.

[0010] Furthermore, the first hydraulic control mechanism includes a thick-rod piston hydraulic cylinder and a first stepper motor. The rod chamber of the thick-rod piston hydraulic cylinder is connected to the output end of the first stepper motor, and the rodless chamber of the thick-rod piston hydraulic cylinder is connected to a sealed hydraulic container. The second hydraulic control mechanism includes a thin-rod piston hydraulic cylinder and a second stepper motor. The rod chamber of the thin-rod piston hydraulic cylinder is connected to the output end of the second stepper motor, and the rodless chamber of the thin-rod piston hydraulic cylinder is connected to a sealed hydraulic container. The cross-sectional area of ​​the piston rod of the thick-rod piston hydraulic cylinder is larger than that of the piston rod of the thin-rod piston hydraulic cylinder.

[0011] By employing the above technical solution, and utilizing a combination of two hydraulic piston mechanisms with different cross-sectional areas, this combination allows for rapid changes in liquid volume during pressure control. The coarse-rod piston hydraulic mechanism enables rapid changes in liquid volume, thereby improving pressure control speed; the fine-rod piston hydraulic mechanism enables precise changes in liquid volume, thus improving pressure control accuracy. A stepper motor drives the piston mechanism, allowing for precise control of its displacement, thereby achieving accurate pressure control.

[0012] Furthermore, the ratio of the cross-sectional area of ​​the piston rod of the coarse rod piston hydraulic cylinder to that of the thin rod piston hydraulic cylinder is 16:1.

[0013] By adopting the above technical solution, combined with the driving torque of the motor, the processing technology of the piston rod, and the sealing components, the optimal control performance of the generator device can be achieved.

[0014] Furthermore, the sensor unit includes: A level sensor used to obtain the liquid level status of a closed hydraulic container; A pressure sensor used to acquire the output pressure signal of a closed hydraulic container; Displacement sensor one for acquiring the piston rod displacement state of a thick-rod piston hydraulic cylinder and displacement sensor two for acquiring the piston rod displacement state of a thin-rod piston hydraulic cylinder.

[0015] By adopting the above technical solution, the liquid level of the sealed hydraulic container, the output pressure of the sealed hydraulic container, and the displacement of the two piston rods can be obtained in real time using different sensors. Based on the data information fed back by each sensor, the motion state of the drive motor and the two sets of piston hydraulic cylinders can be adjusted in real time.

[0016] Furthermore, the pressure sensor is a digital pressure gauge with a pressure range of 250 MPa, an accuracy of 0.01, and a resolution of 0.001 MPa.

[0017] By adopting the above technical solution, the sensor has high accuracy, which in turn leads to high feedback adjustment accuracy, effectively improving the accuracy of pressure control.

[0018] Furthermore, the control processing unit includes an ARM microcontroller, a PFM pulse frequency modulator one, and a PFM pulse frequency modulator two. The input terminal of the ARM microcontroller is communicatively connected to each sensor of the sensor unit, and the output terminal of the ARM microcontroller is communicatively connected to the input terminals of PFM pulse frequency modulator one and PFM pulse frequency modulator two. The output terminal of PFM pulse frequency modulator one is communicatively connected to stepper motor one, and the output terminal of PFM pulse frequency modulator two is communicatively connected to stepper motor two.

[0019] By adopting the above technical solution, the control processing unit can realize the automatic control of the pressure actuator (stepper motor plus hydraulic piston mechanism), thereby realizing the automatic control function of output pressure.

[0020] Furthermore, the control processing unit is electrically connected to a display operation unit.

[0021] By adopting the above technical solution, full-display operation is possible, facilitating on-site monitoring and operation by personnel.

[0022] A pressurization control method for an automatic standard pressure generator for 250MPa liquid media, the pressurization control process is as follows: S1, the pressure output port of the pressure gauge to be tested is installed in a closed hydraulic vessel; S2, input the preset target pressure value to the ARM microcontroller through the display operation unit; S3, Stepper Motor 1 and Stepper Motor 2 start according to the feedback instructions output by the ARM microcontroller. Stepper Motor 1 and Stepper Motor 2 respectively drive the piston rods of the thick rod piston hydraulic cylinder and the thin rod piston hydraulic cylinder to move, change the volume of the liquid medium in the sealed hydraulic container, and control the output pressure of the sealed hydraulic container until the output pressure stabilizes. S4, the output pressure of the sealed hydraulic container is detected by a pressure sensor and fed back to the ARM microcontroller and displayed by the display operation unit.

[0023] The 250MPa automatic standard pressure generator for liquid media described in this application can both accelerate the pressure control speed and improve the pressure control accuracy of the liquid media standard pressure generator, while also realizing automatic pressure control. Compared with existing 250MPa liquid media standard pressure generator products on the market, the control performance (pressure control speed, control accuracy, automation) of the 250MPa automatic standard pressure generator product of this application has been greatly improved. Specifically, this is reflected in the following aspects: 1. The pressurization mechanism of the pressure generator described in this application adopts a combination of two sets of hydraulic pistons with different cross-sectional areas, which can improve the pressure control speed during the pressure control process; therefore, the pressure control speed of the existing 250MPa liquid medium standard pressure generator on the market is more than 2 minutes, while the pressure control speed of the 250MPa liquid medium automatic standard pressure generator product of this application is less than 1 minute. 2. Utilizing a combination of two sets of hydraulic pistons with different cross-sectional areas can also improve pressure control accuracy; simultaneously, employing a stepper motor as the driver for the hydraulic piston mechanism allows for precise control of the piston mechanism's operation, thereby further improving the control accuracy of the output pressure; therefore, the output pressure stability of existing 250MPa liquid medium standard pressure generators on the market is one-thousandth (one-thousandth of full scale), while the output pressure stability of the 250MPa liquid medium automatic standard pressure generator product of this application is five ten-thousandths (five ten-thousandths of full scale). 3. This application uses a pressure closed-loop control system composed of an ARM microcontroller to realize the automatic control function of output pressure and improve the automation level of pressure controller products. Therefore, the existing 250MPa liquid medium standard pressure generators on the market are usually in manual pressure generation mode. The 250MPa liquid medium automatic standard pressure generator product of this application can automatically generate pressure and stably output the target pressure as long as the target pressure value is entered on the interface. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a control principle diagram of an embodiment of this application; Figure 2 This is a connection diagram of the pressure generating unit; In the diagram, 1. Pressure generating unit; 101. Sealed hydraulic container; 102. Thick rod piston hydraulic cylinder; 103. Thin rod piston hydraulic cylinder; 104. Stepper motor one; 105. Stepper motor two; 2. Control and processing unit; 201. PFM pulse frequency modulation one; 202. PFM pulse frequency modulation two; 203. ARM microcontroller; 3. Sensor unit; 301. Liquid level sensor; 302. Pressure sensor; 303. Displacement sensor one; 304. Displacement sensor two. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0028] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0029] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0030] The standard pressure generator for liquid media described in this application is a pressure measurement and control product that controls the output pressure of a liquid medium by compressing the volume of a sealed liquid, and measures the pressure using a pressure sensor and displays the output pressure value on an interface. The maximum liquid pressure value output by the automatic standard pressure generator for liquid media described in this application can reach 250 MPa.

[0031] like Figure 1 The schematic diagram shows a 250MPa automatic standard pressure generator for liquid media, comprising three parts: a pressure generating unit 1, a control processing unit 2, and a sensor unit 3. The control processing unit 2 is also electrically connected to a display and operation unit.

[0032] The pressure generating unit 1 is the core component of the 250MPa automatic standard pressure generator for liquid media in this application. It is used to perform the function of controlling the pressure of the liquid media. The output pressure is controlled by changing the volume of the sealed liquid media. When the volume of the liquid media is compressed, the liquid pressure increases, and vice versa. This pressure is transmitted to the pressure output interface through the liquid media.

[0033] The pressure generating unit 1 is used to output the target pressure to the pressure gauge being tested. The structural composition of the pressure generating unit 1 is as follows: Figure 2 As shown, the pressure generating unit 1 includes a sealed hydraulic container 101 and a pressurizing mechanism for changing the output pressure of the sealed hydraulic container 101. The pressurizing mechanism employs two sets of hydraulic piston mechanism combinations with different cross-sectional areas. Hydraulic piston mechanism combination one includes a thick rod piston hydraulic cylinder 102 and a stepper motor 104. The rod chamber of the thick rod piston hydraulic cylinder 102 is connected to the output end of the stepper motor 104, and the rodless chamber of the thick rod piston hydraulic cylinder 102 is connected to the sealed hydraulic container 101. Hydraulic piston mechanism combination two includes a thin rod piston hydraulic cylinder 103 and a stepper motor 105. The rod chamber of the thin rod piston hydraulic cylinder 103 is connected to the output end of the stepper motor 105, and the rodless chamber of the thin rod piston hydraulic cylinder 103 is connected to the sealed hydraulic container 101.

[0034] This combination enables rapid and precise control of liquid volume changes during pressure control. The coarse-rod piston hydraulic cylinder 102 of hydraulic piston mechanism assembly one can quickly change the liquid volume in the sealed hydraulic container 101, thereby improving pressure control speed. The fine-rod piston hydraulic cylinder 103 of hydraulic piston mechanism assembly two can precisely change the liquid volume in the sealed hydraulic container 101, thereby improving pressure control accuracy. In this application's 250MPa automatic standard pressure generator for liquid media, the coarse-rod piston diameter ratio is 4:1, resulting in a cross-sectional area ratio of 16:1. This means the pressure control speed of the large piston is 16 times that of the small piston, and the pressure control precision of the small piston is 16 times that of the large piston. The pressure control actuator is attached... Figure 2 As shown. Furthermore, the resistance generated by the piston's cross-sectional area when subjected to a liquid pressure of 250 MPa should be less than the force exerted by the corresponding drive motor under its rated output torque.

[0035] In the initial stage of pressure control, using hydraulic piston mechanism combination one alone to perform pressure control can improve the pressure control speed; when the pressure value approaches the target pressure, using hydraulic piston mechanism combination two to perform pressure control can ensure the accuracy when the pressure reaches the target value.

[0036] To precisely control the movement of the coarse rod piston hydraulic cylinder 102 and the fine rod piston hydraulic cylinder 103, stepper motors capable of precisely controlling angular displacement were selected for their drive motors, thereby further improving the accuracy of pressure control. Because stepper motors offer precise control of angular displacement and convenient control of speed and direction, using them to drive the piston mechanism allows for precise control of the piston hydraulic mechanism's displacement, thus achieving precise pressure control. The two stepper motors selected for the 250MPa liquid medium automatic standard pressure generator in this application have a resolution (step angle) of 0.072°. This means that the minimum control amount for a single control stroke can reach two ten-thousandths of a revolution in the transmission stroke (0.072 / 360 = 0.0002), which greatly improves the accuracy of pressure control.

[0037] The sensor unit 3 is communicatively connected to the pressure generating unit 1 and is used to acquire the execution status signal of the pressure generating unit 1. The sensor unit 3 includes a liquid level sensor 301, a pressure sensor 302, a first displacement sensor 303, and a second displacement sensor 304. Among them, the liquid level sensor 301 is used to obtain the liquid level status of the closed hydraulic container 101. When the measured oil level in the tank is very low, the pressurization system must be prohibited from working in order to prevent the pressurization system from malfunctioning due to air intake. The pressure sensor 302 is used to obtain the output pressure signal of the closed hydraulic container 101 and transmit the pressure signal to the ARM microcontroller 203 in a timely manner and display the corresponding pressure value on the display screen. By comparing the pressure value with the pressure reading of the pressure gauge being measured at this time, the pressure gauge being measured can be calibrated. The displacement sensor 303 is used to obtain the piston rod displacement status of the thick rod piston hydraulic cylinder 102. The displacement sensor 304 is used to obtain the piston rod displacement status of the thin rod piston hydraulic cylinder 103. The obtained piston rod displacement status can be used to determine whether the piston rod will exceed the limit position (limit point) during forward or backward operation, which would cause damage to the mechanism.

[0038] Pressure sensor 302 is used to acquire the output pressure value of the 250MPa automatic standard pressure generator for liquid media in this application in real time. As the core component of the automatic standard pressure generator, the accuracy and resolution of pressure sensor 302 are related to the control performance of the liquid media standard pressure generator. Therefore, the pressure sensor 302 of the 250MPa automatic standard pressure generator for liquid media in this application is a digital pressure gauge with a pressure range of 250MPa, an accuracy of 0.01%, and a resolution of 0.001MPa.

[0039] like Figure 1 As shown, the control processing unit 2 is communicatively connected to the pressure generating unit 1 and the sensor unit 3, and is used to acquire signals from the sensor unit 3 and process them to feed back to the pressure generating unit 1. The control processing unit 2 includes an ARM microcontroller 203, a PFM pulse frequency modulation one 201, and a PFM pulse frequency modulation two 202. The input terminal of the ARM microcontroller is communicatively connected to each sensor of the sensor unit 3, and the output terminal of the ARM microcontroller is communicatively connected to the input terminals of the PFM pulse frequency modulation one 201 and the PFM pulse frequency modulation two 202. The output terminal of the PFM pulse frequency modulation one (201) is communicatively connected to the stepper motor one 104, and the output terminal of the PFM pulse frequency modulation two 202 is communicatively connected to the stepper motor two 105.

[0040] The controller is the computational and decision-making center of the pressure control unit, enabling automatic control of the entire pressure generating unit. This application's 250MPa automatic standard pressure generator for liquid media uses a hardware control circuit based on an ARM microcontroller (STM32F407), supplemented by a software PID control algorithm as the controller for the pressure generating unit. Since stepper motors control the angular displacement of the motor shaft through the number of pulses and the rotational speed through the pulse frequency, a PFM (Pulse Frequency Modulation) hardware circuit can be used to control the operation of the stepper motors, thereby achieving automatic pressure control. During pressure control, the controller adjusts the operation of the two stepper motors appropriately based on the real-time pressure values ​​fed back from the pressure sensors.

[0041] The signal processing unit acquires and processes data from various sensors within the automatic standard pressure generator, including pressure sensors, displacement sensors, and level sensors. Since these sensors output both analog and digital signals, the signal processing unit must be able to process both. The core of the signal processing unit is an ARM microcontroller. The analog signal acquisition unit, composed of the microcontroller and an external AD converter circuit, acquires the analog output signals from the sensors. These analog signals are then processed by the AD converter and the microcontroller and finally converted into digital signals. The digital signal acquisition unit, composed of the STM32F407 microcontroller and an external interface conversion circuit in the 250MPa automatic standard pressure generator for liquid media in this application, can acquire the pressure values ​​from the digital pressure sensors. During pressure control, the signal processing unit feeds back the pressure sensor values ​​to the control loop in real time to achieve closed-loop control of the output pressure of the sealed hydraulic vessel. Furthermore, the signal processing unit also sends the pressure values ​​to the display unit for output display.

[0042] The display unit's display section shows the real-time pressure value, generator operating status, pressure change curve, and other relevant information of the 250MPa automatic standard pressure generator for liquid media. The operation section allows the operator to input the target pressure value, start or stop pressure control, and execute other related functions. The 250MPa automatic standard pressure generator of this application uses a 10-inch LCD screen to display pressure-related information, and a 10-inch capacitive touchscreen for operation.

[0043] The pressurization control process of the 250MPa automatic standard pressure generator for liquid media in this application is as follows: S1, the pressure gauge to be tested is installed at the pressure output port of the closed hydraulic container 101; S2, input the preset target pressure value to the ARM microcontroller through the display operation unit; S3, stepper motor 104 and stepper motor 2105 are started according to the feedback instructions output by the ARM microcontroller. Stepper motor 104 and stepper motor 2105 respectively drive the piston rod of the thick rod piston hydraulic cylinder 102 and the thin rod piston hydraulic cylinder 103 to change the volume of the liquid medium in the sealed hydraulic container 101 and control the output pressure of the sealed hydraulic container 101 until the output pressure is stable. S4, the output pressure of the sealed hydraulic container 101 is detected by the pressure sensor 302 and fed back to the ARM microcontroller and displayed by the display operation unit.

[0044] As can be seen from the above embodiments, the 250MPa liquid medium automatic standard pressure generator product of this application firstly adopts an electric drive pressurization mechanism to operate without manual operation; secondly, its pressurization mechanism adopts a combination of two sets of hydraulic piston mechanisms with different cross-sectional areas. In the process of pressure control, the thicker piston hydraulic mechanism can realize the function of rapidly changing the liquid volume, thereby improving the pressure control speed, while the thinner piston hydraulic mechanism can realize the function of precisely changing the liquid volume, thereby improving the accuracy of pressure control; finally, the drive motor is a stepper motor that can accurately control angular displacement, thereby further improving the accuracy of pressure control.

[0045] The 250MPa automatic standard pressure generator for liquid media in this application combines the pressure control speed and accuracy of an automatic standard pressure generator. The actuator design of the pressure controller uses a combination of two hydraulic piston mechanisms of different diameters as the actuator of the pressure control unit. The coarse-rod piston hydraulic mechanism enables rapid change of liquid volume, improving the pressure control speed; the fine-rod piston hydraulic mechanism enables precise change of liquid volume, improving the pressure control accuracy. Using the coarse-rod piston hydraulic mechanism alone in the initial stage of pressure control improves the pressure control speed, while switching to the fine-rod piston hydraulic mechanism when the pressure value approaches the target pressure ensures accuracy when the pressure reaches the target value.

[0046] Two stepper motors act as drivers for the pressure control unit, driving two sets of hydraulic piston mechanisms. Because stepper motors offer precise control of angular displacement and convenient control of speed and direction, using them to drive the piston mechanisms allows for precise control of the piston hydraulic mechanism's displacement, thereby achieving precise pressure control.

[0047] The controller is the computational and decision-making center of the pressure control unit, enabling automatic control of the pressure control unit. The controller design employs a hardware control circuit based on an ARM microcontroller, supplemented by a software control algorithm. Since stepper motors control the angular displacement of the motor shaft through the number of pulses and the rotational speed through the pulse frequency, the PWM peripheral of the ARM microcontroller can fully realize the operation control of the stepper motor. The pressure controller based on the ARM microcontroller system can achieve automatic control of the pressure actuators (stepper motor and hydraulic control mechanism), thereby realizing the automatic control function of the output pressure.

[0048] In summary, the technical solution adopted in this application for a 250MPa automatic standard pressure generator for liquid media not only accelerates the pressure control speed of the liquid media standard pressure generator but also improves its pressure control accuracy, while simultaneously achieving automatic pressure control. Compared to existing 250MPa liquid media standard pressure generator products on the market, the control performance (pressure control speed, control accuracy, and automation) of this application's 250MPa automatic standard pressure generator for liquid media is significantly improved.

[0049] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. An automatic standard pressure generator for 250MPa liquid media, characterized in that, include: The pressure generating unit (1) is used to output standard pressure to the pressure gauge being tested; The sensor unit (3) is communicatively connected to the pressure generating unit (1) and is used to acquire the execution status signal of the pressure generating unit (1); The control processing unit (2) is communicatively connected to the pressure generating unit (1) and the sensor unit (3) to acquire the signal from the sensor unit (3) and process it to feed back to the pressure generating unit (1). The pressure generating unit (1) includes a closed hydraulic container (101) and a pressurizing mechanism for changing the output pressure of the closed hydraulic container (101); The pressurizing mechanism includes two sets of hydraulic control mechanisms with different output pressures. The input ends of the two sets of hydraulic control mechanisms are respectively connected to the control processing unit (2) and the output ends of the two sets of hydraulic control mechanisms are respectively connected to the sealed hydraulic container (101). The pressurization mechanism includes a hydraulic control mechanism one for controlling the rate of change of the output pressure of the sealed hydraulic container (101) and a hydraulic control mechanism two for controlling the accuracy of the change of the output pressure of the sealed hydraulic container (101). The hydraulic control mechanism includes a thick rod piston hydraulic cylinder (102) and a stepper motor (104). The rod chamber of the thick rod piston hydraulic cylinder (102) is connected to the output end of the stepper motor (104), and the rodless chamber of the thick rod piston hydraulic cylinder (102) is connected to the sealed hydraulic container (101). The second hydraulic control mechanism includes a thin rod piston hydraulic cylinder (103) and a second stepper motor (105). The rod chamber of the thin rod piston hydraulic cylinder (103) is connected to the output end of the second stepper motor (105), and the rodless chamber of the thin rod piston hydraulic cylinder (103) is connected to the sealed hydraulic container (101). The cross-sectional area of ​​the piston rod of the thick rod piston hydraulic cylinder (102) is larger than that of the piston rod of the thin rod piston hydraulic cylinder (103); The ratio of the cross-sectional area of ​​the piston rod of the thick rod piston hydraulic cylinder (102) to that of the cross-sectional area of ​​the piston rod of the thin rod piston hydraulic cylinder (103) is 16:1; The control processing unit (2) includes an ARM microcontroller (203), a PFM pulse frequency modulation one (201), and a PFM pulse frequency modulation two (202). The input terminal of the ARM microcontroller is communicatively connected to each sensor of the sensor unit (3). The output terminal of the ARM microcontroller is communicatively connected to the input terminals of PFM pulse frequency modulation one (201) and PFM pulse frequency modulation two (202). The output terminal of PFM pulse frequency modulation one (201) is communicatively connected to stepper motor one (104), and the output terminal of PFM pulse frequency modulation two (202) is communicatively connected to stepper motor two (105).

2. The 250MPa automatic standard pressure generator for liquid media according to claim 1, characterized in that, The sensor unit (3) includes: A level sensor (301) for obtaining the liquid level status of a closed hydraulic container (101). Pressure sensor (302) used to acquire the output pressure signal of the closed hydraulic vessel (101); Displacement sensor one (303) for obtaining the piston rod displacement state of the thick rod piston hydraulic cylinder (102) and displacement sensor two (304) for obtaining the piston rod displacement state of the thin rod piston hydraulic cylinder (103).

3. The 250MPa automatic standard pressure generator for liquid media according to claim 2, characterized in that, The pressure sensor (302) is a digital pressure gauge with a pressure range of 250 MPa, an accuracy of 0.01, and a resolution of 0.001 MPa.

4. The 250MPa automatic standard pressure generator for liquid media according to claim 1, characterized in that, The control processing unit (2) is electrically connected to the display operation unit.

5. A pressurization control method based on the 250MPa automatic standard pressure generator for liquid media as described in any one of claims 1-4, characterized in that, The pressurization control process is as follows: S1, the pressure output port of the pressure gauge to be tested is installed in the closed hydraulic vessel (101); S2, input the preset target pressure value to the ARM microcontroller through the display operation unit; S3, Stepper motor one (104) and stepper motor two (105) are started according to the feedback instructions output by the ARM microcontroller. Stepper motor one (104) and stepper motor two (105) respectively drive the piston rods of the thick rod piston hydraulic cylinder (102) and the thin rod piston hydraulic cylinder (103) to change the volume of the liquid medium in the sealed hydraulic container (101) and control the output pressure of the sealed hydraulic container (101) until the output pressure is stable. S4, the output pressure of the closed hydraulic container (101) is detected by the pressure sensor (302) and fed back to the ARM microcontroller and displayed by the display operation unit; In the initial stage of pressure control, hydraulic control mechanism one is used alone to perform pressure control in order to improve the pressure control speed; when the pressure value approaches the target pressure, hydraulic control mechanism two is used to perform pressure control.

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