阅读说明：本技术 一种基于液氧流量调节自动流程控制及其保护方法 (Automatic flow control and protection method based on liquid oxygen flow regulation ) 是由 史向前 郭洪业 关英海 李俊杰 于 2020-12-25 设计创作，主要内容包括：本发明公开了一种基于液氧流量调节自动流程控制及其保护方法,该控制系统,包括：阀门、传感器、上位机和下位机；所述上位机与下位机之间进行数据交换；所述下位机分别与阀门和传感器电气连接,以进行数据传输和控制；所述上位机用于实现人机交换,上位机的控制单元设有定压阀自动流程操作软件,所述软件的操作界面设有功能按钮；当操作人员通过所述软件的操作界面选择功能按钮时,所述控制单元将所述功能按钮对应的控制指令发送给下位机；本发明能够通过程序实现增压管路的多项可选、自动增压、步幅可控、实时判断、阀门保护措施到位,可节省操作时间、提高操作效率、简便智能,为液氧增压系统提供了保障。(The invention discloses an automatic flow control and protection method based on liquid oxygen flow regulation, and the control system comprises: the device comprises a valve, a sensor, an upper computer and a lower computer; data exchange is carried out between the upper computer and the lower computer; the lower computer is electrically connected with the valve and the sensor respectively so as to transmit and control data; the upper computer is used for realizing man-machine exchange, a control unit of the upper computer is provided with automatic flow operation software of a constant pressure valve, and an operation interface of the software is provided with a function button; when an operator selects a function button through the operation interface of the software, the control unit sends a control instruction corresponding to the function button to a lower computer; the invention can realize multiple optional, automatic pressurization, controllable stride, real-time judgment and in-place valve protection measures of the pressurization pipeline through a program, can save the operation time, improve the operation efficiency, is simple, convenient and intelligent, and provides guarantee for the liquid oxygen pressurization system.)

1. An automatic process control system based on liquid oxygen flow regulation, comprising: valves and sensors; the valve and the sensor are respectively arranged on a pressure increasing pipeline between a nitrogen source of the liquid oxygen supply system and the liquid oxygen tank, and the valve comprises: a constant pressure valve and a pressure-increasing cutoff valve; the sensor includes: pressure sensor a and pressure sensor C; the constant pressure valve is positioned at the side of the nitrogen source, and the pressure-increasing cut-off valve is positioned at the side of the liquid oxygen tank; the pressure sensor A is positioned between the constant pressure valve and the pressure-boosting cut-off valve, and the pressure sensor C is positioned between the pressure-boosting cut-off valve and the liquid oxygen tank; the constant pressure valve is used for controlling the pressure in the pressurization pipeline to be a set value, and the pressurization cut-off valve is used for controlling the flow of a medium in the pressurization pipeline; the pressure sensor is used for detecting the pressure in the pressurization pipeline;

it is characterized by also comprising: an upper computer and a lower computer;

data exchange is carried out between the upper computer and the lower computer;

the lower computer is electrically connected with the valve and the sensor respectively so as to transmit and control data;

the upper computer is used for realizing man-machine exchange, the control unit of the upper computer is provided with automatic flow operation software of a constant pressure valve, the operation interface of the software is provided with function buttons, and the function buttons comprise: the method comprises the following steps of (1) selecting a pressurization pipeline, starting pressurization, inputting a pressurization set value, stopping pressurization and giving an alarm when the pressurization is overtime; when an operator selects a function button through the operation interface of the software, the control unit sends a control instruction corresponding to the function button to a lower computer;

the lower computer comprises: the PLC comprises a power supply module, a communication module, a digital quantity input module, a digital quantity output module, an analog quantity input module and an analog quantity output module;

the power supply module is used for supplying power to the PLC;

one end of the communication module is in data transmission with the upper computer through an industrial Ethernet, and the other end of the communication module is in data transmission with the PLC, so that data exchange between the PLC and the upper computer is realized;

the PLC is internally stored with a control program and is used for acquiring and storing feedback parameters of the valve and the sensor through a digital quantity input module and an analog quantity input module, and the feedback parameters comprise: the method comprises the following steps of (1) increasing the pressure of a switch limit signal of a cut-off valve and pressure data of a sensor, sending the feedback parameters to an upper computer, and displaying the feedback parameters on an operation interface of automatic flow operation software of a constant pressure valve of the upper computer; the PLC is also used for receiving a control instruction of the upper computer and controlling the opening and closing of the pressure-boosting cut-off valve and the opening of the constant pressure valve through the digital output module and the analog output module; the PLC is also used for setting a pressurization operation flow of the liquid oxygen supply system, namely setting the action sequence and time interval of each valve and carrying out corresponding action processing on the feedback parameters of the valves and the sensors.

2. The system of claim 1, wherein the system further comprises a flow control valve for controlling the flow of liquid oxygen,

the digital quantity input module is used for acquiring a switch limit signal of the pressurization shut-off valve and sending the switch limit signal to the PLC;

the digital quantity output module is used for receiving a control signal of the PLC and controlling the on-off of the pressurization shut-off valve;

the analog quantity input module is used for acquiring pressure and temperature data of the sensor and sending the pressure and temperature data to the PLC;

and the analog output module is used for receiving a control signal of the PLC and controlling the opening of the constant pressure valve.

3. The automatic process control system based on liquid oxygen flow regulation of claim 1, further comprising a pressure sensor B, wherein the pressure sensor B is located between the constant pressure valve and the nitrogen source.

4. The system of claim 1, further comprising a temperature sensor between the pressure cutoff valve and the liquid oxygen tank; the temperature sensor is used for measuring the temperature in the pressurization pipeline.

5. A protection method based on an automatic flow control system for liquid oxygen flow regulation is based on the automatic flow control system for liquid oxygen flow regulation as claimed in claim 1, and is characterized in that the protection method comprises the following specific steps:

step 1, operating an operation interface of automatic flow operation software of a constant pressure valve of an upper computer by an operator, and selecting a corresponding pressure boost pipeline through a function button selected by the pressure boost pipeline;

step 2, an operator inputs a supercharging target value through a function button of a supercharging set value input box; the upper computer sends the pressurization target value to a PLC of a lower computer, the PLC sets the constant pressure valve, the pressure of the constant pressure valve is set as the pressurization target value, and meanwhile the pressurization step length of the constant pressure valve is set as a step length set value;

step 3, an operator starts an automatic pressurization program through a function button for starting pressurization; the upper computer sends a control instruction for starting pressurization to a PLC of the lower computer, the PLC controls a constant pressure valve and a pressurization cut-off valve to be opened, and controls the pressure of the constant pressure valve to be increased by a step length set value according to each set time length A to be pressurized until the pressure is equal to the pressurization target value; enabling nitrogen of a nitrogen source to enter the liquid oxygen tank through a pressurization pipeline, increasing the pressure of the liquid oxygen tank to a set value, acquiring pressure and temperature data of a measuring point of the pressurization pipeline where a sensor is located through a PLC (programmable logic controller) in the pressurization process of the liquid oxygen tank, and judging whether the pressure of the constant pressure valve is adjusted in place or not according to the pressure and temperature data; the specific judgment process is as follows:

(1) the PLC judges whether the pressure measured by the pressure sensor A exceeds the pressurization target value of the constant pressure valve in real time, if so, the pressurization shut-off valve is closed, and the pressurization of the liquid oxygen tank is stopped; if not, continuously keeping the pressurization stop valve in an opening state;

(2) the PLC judges whether the difference between the pressure measured by the pressure sensor C and the pressure measured by the pressure sensor A is within a set range in real time, and if so, the PLC continuously keeps the pressurization shut-off valve in an open state; if the pressure of the liquid oxygen tank is not within the set range, closing the pressure-increasing stop valve and stopping the pressure increase of the liquid oxygen tank;

(3) setting the pressurization target value of the constant pressure valve to be M, the step length setting value of the constant pressure valve to be L and the initial pressure of the constant pressure valve to be P, setting the pressure setting value of the constant pressure valve after the first set time length A is pressurized to be P + L, setting the pressure setting value of the constant pressure valve after the second set time length A is pressurized to be P +2L, setting the pressure setting value of the constant pressure valve after the third set time length A is pressurized to be P +3L and …, setting the pressure setting value of the constant pressure valve after the last set time length A is pressurized to be P + nL and equal to the pressurization target value M;

the PLC judges once every set time length A and judges whether the difference between the pressure measured by the pressure sensor A and the current corresponding pressure set value is less than or equal to a step length set value L or not;

if the step length set value is less than or equal to L, the pressure of the constant pressure valve is normal, the PLC automatically sets a pressure set value after the pressure of the next set time length A is increased by the constant pressure valve until the pressure set value of the constant pressure valve is equal to the pressure increase target value M;

if the step length is larger than the set value L, the constant pressure valve is abnormal in work; if the pressure measured by the pressure sensor A is not less than or equal to the set step length value L after the set time length B is set, a function button for alarming the pressurization overtime on an operation interface of automatic flow operation software of a constant pressure valve of the upper computer prompts the pressurization overtime, closes the pressurization stop valve, stops the pressurization of the liquid oxygen tank, and simultaneously checks the constant pressure valve and the pressurization pipeline; if the pressure measured by the pressure sensor A is less than or equal to the step length set value and is L after the set time length B is set, the pressure of the constant pressure valve is gradually increased to the current corresponding pressure set value, the PLC automatically sets the pressure set value after the pressure of the next set time length A is increased until the pressure set value of the constant pressure valve is equal to the pressure increase target value M;

(4) when the pressure set value of the constant pressure valve is equal to the pressurization target value, the PLC judges whether the pressure of the liquid oxygen tank meets the set value or not through the pressure measured by the pressure sensor C, if yes, the execution of the automatic pressurization program is finished, and the automatic pressurization is finished through a function button for stopping pressurization on an operation interface of automatic flow operation software of the constant pressure valve of the upper computer.

6. The protection method of the automatic flow control system based on liquid oxygen flow regulation as claimed in claim 5, wherein an operator can stop the automatic pressurization process at any time through a function button for pressurization stop on an operation interface of the automatic flow operation software of the constant pressure valve.

7. The protection method of the automatic flow control system based on liquid oxygen flow regulation as claimed in claim 5, wherein an operator intervenes in the pressurization process according to the pressurization condition of the liquid oxygen tank, i.e. during the pressurization process, the valve can be operated by the PLC, the automatic pressurization program is stopped, and the state of the non-operated valve is maintained, i.e. the constant pressure valve is normally open and the pressurization stop valve is normally closed.

8. The protection method of the automatic process control system based on liquid oxygen flow regulation as claimed in claim 5, characterized in that the pressure boost set value input box on the operation interface of the automatic process operation software of the constant pressure valve of the upper computer can be manually set, that is, the pressure set value of the constant pressure valve is manually input after every set time length A until the pressure boost set value is equal to the pressure boost target value.

Technical Field

The invention belongs to the technical field of flow regulation, and particularly relates to automatic flow control and a protection method thereof based on liquid oxygen flow regulation.

Background

In order to meet the requirement of a certain high enthalpy test facility on oxygen flow in each test state, oxygen consumed by a direct combustion heater is supplemented, the molar content of oxygen in a high enthalpy working medium is ensured to be consistent with that of air, a liquid oxygen supply system adopts a nitrogen extrusion mode, 4 parts of completely same supply units form a test bed to supply liquid oxygen with stable pressure and stable flow, and precooling processes before a test and blowing-off work after the test are completed. The main component of the liquid oxygen supply system is a constant pressure valve. Whether the constant pressure valve can normally work according to requirements or not is a key step of whole system debugging and connection in relation to whether a liquid oxygen supply system can provide oxygen with corresponding flow for experimental facilities or not, the consideration is that the boost pressure is higher, the valve circulation capacity is larger, the number of boost pipelines is more, the four-way boost manual operation is more complicated, the system operation is safe and the like, and higher requirements are provided for the automatic control of the constant pressure valve.

Disclosure of Invention

In view of the above, the invention provides an automatic flow control and protection method based on liquid oxygen flow adjustment, which can realize multiple optional, automatic pressurization, controllable stride, real-time judgment and in-place valve protection measures of a pressurization pipeline through a program, save operation time, improve operation efficiency, be simple, convenient and intelligent, and provide guarantee for a liquid oxygen pressurization system.

The invention is realized by the following technical scheme:

an automatic process control system based on liquid oxygen flow regulation, comprising: valves and sensors; the valve and the sensor are respectively arranged on a pressure increasing pipeline between a nitrogen source of the liquid oxygen supply system and the liquid oxygen tank, and the valve comprises: a constant pressure valve and a pressure-increasing cutoff valve; the sensor includes: pressure sensor a and pressure sensor C; the constant pressure valve is positioned at the side of the nitrogen source, and the pressure-increasing cut-off valve is positioned at the side of the liquid oxygen tank; the pressure sensor A is positioned between the constant pressure valve and the pressure-boosting cut-off valve, and the pressure sensor C is positioned between the pressure-boosting cut-off valve and the liquid oxygen tank; the constant pressure valve is used for controlling the pressure in the pressurization pipeline to be a set value, and the pressurization cut-off valve is used for controlling the flow of a medium in the pressurization pipeline; the pressure sensor is used for detecting the pressure in the pressurization pipeline;

further comprising: an upper computer and a lower computer;

data exchange is carried out between the upper computer and the lower computer;

the lower computer is electrically connected with the valve and the sensor respectively so as to transmit and control data;

the upper computer is used for realizing man-machine exchange, the control unit of the upper computer is provided with automatic flow operation software of a constant pressure valve, the operation interface of the software is provided with function buttons, and the function buttons comprise: the method comprises the following steps of (1) selecting a pressurization pipeline, starting pressurization, inputting a pressurization set value, stopping pressurization and giving an alarm when the pressurization is overtime; when an operator selects a function button through the operation interface of the software, the control unit sends a control instruction corresponding to the function button to a lower computer;

the lower computer comprises: the PLC comprises a power supply module, a communication module, a digital quantity input module, a digital quantity output module, an analog quantity input module and an analog quantity output module;

the power supply module is used for supplying power to the PLC;

one end of the communication module is in data transmission with the upper computer through an industrial Ethernet, and the other end of the communication module is in data transmission with the PLC, so that data exchange between the PLC and the upper computer is realized;

the PLC is internally stored with a control program and is used for acquiring and storing feedback parameters of the valve and the sensor through a digital quantity input module and an analog quantity input module, and the feedback parameters comprise: the method comprises the following steps of (1) increasing the pressure of a switch limit signal of a cut-off valve and pressure data of a sensor, sending the feedback parameters to an upper computer, and displaying the feedback parameters on an operation interface of automatic flow operation software of a constant pressure valve of the upper computer; the PLC is also used for receiving a control instruction of the upper computer and controlling the opening and closing of the pressure-boosting cut-off valve and the opening of the constant pressure valve through the digital output module and the analog output module; the PLC is also used for setting a pressurization operation flow of the liquid oxygen supply system, namely setting the action sequence and time interval of each valve and carrying out corresponding action processing on the feedback parameters of the valves and the sensors.

Further, the digital quantity input module is used for acquiring a switch limit signal of the pressurization shut-off valve and sending the switch limit signal to the PLC;

the digital quantity output module is used for receiving a control signal of the PLC and controlling the on-off of the pressurization shut-off valve;

the analog quantity input module is used for acquiring pressure and temperature data of the sensor and sending the pressure and temperature data to the PLC;

and the analog output module is used for receiving a control signal of the PLC and controlling the opening of the constant pressure valve.

Further, the device also comprises a pressure sensor B, and the pressure sensor B is positioned between the constant pressure valve and the nitrogen source.

Further, the device also comprises a temperature sensor, wherein the temperature sensor is positioned between the pressurization stop valve and the liquid oxygen tank; the temperature sensor is used for measuring the temperature in the pressurization pipeline.

A protection method based on a liquid oxygen flow regulation automatic process control system is based on the liquid oxygen flow regulation automatic process control system, and comprises the following specific steps:

step 1, operating an operation interface of automatic flow operation software of a constant pressure valve of an upper computer by an operator, and selecting a corresponding pressure boost pipeline through a function button selected by the pressure boost pipeline;

step 2, an operator inputs a supercharging target value through a function button of a supercharging set value input box; the upper computer sends the pressurization target value to a PLC of a lower computer, the PLC sets the constant pressure valve, the pressure of the constant pressure valve is set as the pressurization target value, and meanwhile the pressurization step length of the constant pressure valve is set as a step length set value;

step 3, an operator starts an automatic pressurization program through a function button for starting pressurization; the upper computer sends a control instruction for starting pressurization to a PLC of the lower computer, the PLC controls a constant pressure valve and a pressurization cut-off valve to be opened, and controls the pressure of the constant pressure valve to be increased by a step length set value according to each set time length A to be pressurized until the pressure is equal to the pressurization target value; enabling nitrogen of a nitrogen source to enter the liquid oxygen tank through a pressurization pipeline, increasing the pressure of the liquid oxygen tank to a set value, acquiring pressure and temperature data of a measuring point of the pressurization pipeline where a sensor is located through a PLC (programmable logic controller) in the pressurization process of the liquid oxygen tank, and judging whether the pressure of the constant pressure valve is adjusted in place or not according to the pressure and temperature data; the specific judgment process is as follows:

(1) the PLC judges whether the pressure measured by the pressure sensor A exceeds the pressurization target value of the constant pressure valve in real time, if so, the pressurization shut-off valve is closed, and the pressurization of the liquid oxygen tank is stopped; if not, continuously keeping the pressurization stop valve in an opening state;

(2) the PLC judges whether the difference between the pressure measured by the pressure sensor C and the pressure measured by the pressure sensor A is within a set range in real time, and if so, the PLC continuously keeps the pressurization shut-off valve in an open state; if the pressure of the liquid oxygen tank is not within the set range, closing the pressure-increasing stop valve and stopping the pressure increase of the liquid oxygen tank;

(3) setting the pressurization target value of the constant pressure valve to be M, the step length setting value of the constant pressure valve to be L and the initial pressure of the constant pressure valve to be P, setting the pressure setting value of the constant pressure valve after the first set time length A is pressurized to be P + L, setting the pressure setting value of the constant pressure valve after the second set time length A is pressurized to be P +2L, setting the pressure setting value of the constant pressure valve after the third set time length A is pressurized to be P +3L and …, setting the pressure setting value of the constant pressure valve after the last set time length A is pressurized to be P + nL and equal to the pressurization target value M;

the PLC judges once every set time length A and judges whether the difference between the pressure measured by the pressure sensor A and the current corresponding pressure set value is less than or equal to a step length set value L or not;

if the step length set value is less than or equal to L, the pressure of the constant pressure valve is normal, the PLC automatically sets a pressure set value after the pressure of the next set time length A is increased by the constant pressure valve until the pressure set value of the constant pressure valve is equal to the pressure increase target value M;

if the step length is larger than the set value L, the constant pressure valve is abnormal in work; if the pressure measured by the pressure sensor A is not less than or equal to the set step length value L after the set time length B is set, a function button for alarming the pressurization overtime on an operation interface of automatic flow operation software of a constant pressure valve of the upper computer prompts the pressurization overtime, closes the pressurization stop valve, stops the pressurization of the liquid oxygen tank, and simultaneously checks the constant pressure valve and the pressurization pipeline; if the pressure measured by the pressure sensor A is less than or equal to the step length set value and is L after the set time length B is set, the pressure of the constant pressure valve is gradually increased to the current corresponding pressure set value, the PLC automatically sets the pressure set value after the pressure of the next set time length A is increased until the pressure set value of the constant pressure valve is equal to the pressure increase target value M;

(4) when the pressure set value of the constant pressure valve is equal to the pressurization target value, the PLC judges whether the pressure of the liquid oxygen tank meets the set value or not through the pressure measured by the pressure sensor C, if yes, the execution of the automatic pressurization program is finished, and the automatic pressurization is finished through a function button for stopping pressurization on an operation interface of automatic flow operation software of the constant pressure valve of the upper computer.

Furthermore, an operator can stop the automatic pressurization program at any time through a function button for pressurization stop on an operation interface of the automatic process operation software of the constant pressure valve.

Further, the pressure boost process is intervened according to the pressure boost condition of liquid oxygen jar to operating personnel, promptly at the pressure boost in-process, accessible PLC operates the valve, stops automatic pressure boost procedure, and keeps the unoperated valve state, and constant pressure valve normally opens promptly, and pressure boost shut-off valve normal close.

Further, a pressure increase set value input box on an operation interface of the automatic process operation software of the constant pressure valve of the upper computer can be manually set, namely, the pressure set value of the constant pressure valve is manually input after each set time length A until the pressure set value is equal to the pressure increase target value.

Has the advantages that: (1) the method is configured through automatic flow operation software of a constant pressure valve in an upper computer, sets parameters and trigger instructions, receives feedback signals and displays corresponding supercharging parameters in real time; the lower computer receives the instruction, executes the corresponding functional module program, protects the program to monitor in real time in the pressurizing process and feeds back signals in time; the automatic, intelligent and simple man-machine interaction of liquid oxygen flow regulation is realized, the operation is stable, the pressurization supply task of the liquid oxygen system can be well completed, the logic control of the constant pressure valve is met, and the full system test is fully guaranteed.

(2) The upper computer of the invention can send out instructions and receive feedback, can flexibly configure the pressure-increasing road and the pressure-increasing target pressure, and display the corresponding measuring point value and the valve state in real time, and the pressure-increasing process is clear and convenient and simple to operate; meanwhile, the manual operation function is reserved, and the automatic pressurization program is independent and not interfered with each other, and can be switched according to the operation condition.

(3) The PLC can complete uploading and issuing of control instructions, data transmission, processing of feedback signals of the valve (namely switch limit signals of the valve), and recording of parameters such as temperature and pressure sent by the sensor; when any one feedback parameter reaches a set value, the PLC performs protection action on the liquid oxygen supply system to protect the safety of the liquid oxygen system, if an abnormal condition occurs, a protection program is started preferentially to execute corresponding process operation, and the operation risk of the pressurization system is reduced.

Drawings

FIG. 1 is a schematic diagram of the present invention;

Detailed Description

The invention is described in detail below by way of example with reference to the accompanying drawings.

Example 1:

this embodiment provides an automatic flow control system based on liquid oxygen flow adjustment, includes: the system comprises an upper computer, a lower computer, a valve and a sensor;

the valve and the sensor are respectively arranged on a pressure increasing pipeline between a nitrogen source of the liquid oxygen supply system and the liquid oxygen tank, and the valve comprises: a constant pressure valve and a pressure-increasing cutoff valve; the sensor includes: three pressure sensors and one temperature sensor; the constant pressure valve is positioned at the side of the nitrogen source, and the pressure-increasing cut-off valve is positioned at the side of the liquid oxygen tank; enabling the three pressure sensors to be a pressure sensor A, a pressure sensor B and a pressure sensor C respectively; the pressure sensor A is positioned between the constant pressure valve and the pressure-boosting cut-off valve, the pressure sensor B is positioned between the constant pressure valve and the nitrogen source, and the pressure sensor C is positioned between the pressure-boosting cut-off valve and the liquid oxygen tank; the temperature sensor is positioned between the pressure-increasing stop valve and the liquid oxygen tank; the constant pressure valve is used for controlling the pressure in the pressurization pipeline to be a set value, and the pressurization cut-off valve is used for controlling the flow of a medium in the pressurization pipeline; the pressure sensor is used for detecting the pressure in the pressurization pipeline, and the temperature sensor is used for measuring the temperature in the pressurization pipeline;

referring to fig. 1, the upper computer and the lower computer exchange data through an industrial ethernet;

the lower computer is electrically connected with the valve and the sensor respectively so as to transmit and control data;

the system comprises an upper computer, a control unit of the upper computer, a configuration software Labview, a constant pressure valve automatic flow operation software and a control unit of the upper computer, wherein the upper computer is used for realizing man-machine exchange, and the constant pressure valve automatic flow operation software is written by the configuration software Labview; the operation interface of software is equipped with the function button, the function button includes: the method comprises the following steps of (1) selecting a pressurization pipeline, starting pressurization, inputting a pressurization set value, stopping pressurization and giving an alarm when the pressurization is overtime; when an operator selects a function button through the operation interface of the software, the control unit sends a control instruction corresponding to the function button to a lower computer;

the lower computer comprises: the PLC comprises a power supply module, a communication module, a digital quantity input module, a digital quantity output module, an analog quantity input module and an analog quantity output module;

the power supply module is used for supplying power to the PLC;

one end of the communication module is in data transmission with the upper computer through an industrial Ethernet, and the other end of the communication module is in data transmission with the PLC, so that data exchange between the PLC and the upper computer is realized;

the PLC adopts an ohm dragon series; a control program is stored in the PLC, the control program is written by CX-one software, and an independent program segment is provided for executing a supercharging task, wherein the supercharging task comprises: communication, valve control, sensor data acquisition, data processing, pressurization process setting and safety function setting; the PLC is used for acquiring and storing feedback parameters (namely, a switch limit signal of the valve and pressure and temperature data of the sensor) of the valve and the sensor through the digital quantity input module and the analog quantity input module, sending the feedback parameters to the upper computer, and displaying the feedback parameters on an operation interface of automatic flow operation software of a constant pressure valve of the upper computer; the PLC is also used for receiving a control instruction of the upper computer and controlling the opening and closing of the valve through the digital output module and the analog output module; the PLC is also used for setting a pressurization operation flow of the liquid oxygen supply system, namely setting the action sequence and time interval of each valve and performing corresponding action processing on the feedback parameters of the valves and the sensors;

the digital quantity input module is used for acquiring a switch limit signal of the pressurization shut-off valve and sending the switch limit signal to the PLC;

the digital quantity output module is used for receiving a control signal of the PLC and controlling the on-off of the pressurization shut-off valve;

the analog quantity input module is used for acquiring pressure and temperature data of the sensor and sending the pressure and temperature data to the PLC;

and the analog output module is used for receiving a control signal of the PLC and controlling the opening of the constant pressure valve.

Example 2:

the embodiment provides a protection method of an automatic process control system based on liquid oxygen flow regulation, which comprises the following specific steps:

step 1, operating an operation interface of automatic flow operation software of a constant pressure valve of an upper computer by an operator, and selecting a corresponding pressure boost pipeline through a function button selected by the pressure boost pipeline;

step 2, an operator inputs a supercharging target value through a function button of a supercharging set value input box; the upper computer sends the pressurization target value to a PLC of a lower computer, the PLC sets the constant pressure valve, the pressure of the constant pressure valve is set as the pressurization target value, and meanwhile the pressurization step length of the constant pressure valve is set as a step length set value;

step 3, an operator starts an automatic pressurization program through a function button for starting pressurization; the upper computer sends a control instruction for starting pressurization to a PLC of the lower computer, the PLC controls a constant pressure valve and a pressurization cut-off valve to be opened, and controls the pressure of the constant pressure valve to be increased by a step length set value every 10s until the pressure is equal to the pressurization target value; enabling nitrogen of a nitrogen source to enter the liquid oxygen tank through a pressurization pipeline, increasing the pressure of the liquid oxygen tank to a set value, acquiring pressure and temperature data of a measuring point of the pressurization pipeline where a sensor is located through a PLC (programmable logic controller) in the pressurization process of the liquid oxygen tank, and judging whether the pressure of the constant pressure valve is adjusted in place or not according to the pressure and temperature data; the specific judgment process is as follows:

(1) the PLC judges whether the pressure measured by the pressure sensor A exceeds the pressurization target value of the constant pressure valve in real time, if so, the pressurization shut-off valve is closed, and the pressurization of the liquid oxygen tank is stopped; if not, continuously keeping the pressurization stop valve in an opening state;

(2) the PLC judges whether the difference between the pressure in the liquid oxygen tank (namely the pressure measured by the pressure sensor C) and the pressure measured by the pressure sensor A is within a set range in real time, and if so, the PLC continuously keeps the pressurization shut-off valve in an open state; if the pressure of the liquid oxygen tank is not within the set range, closing the pressure-increasing stop valve and stopping the pressure increase of the liquid oxygen tank;

(3) setting the pressurization target value of the constant pressure valve as M, the step length setting value of the constant pressure valve as L and the initial pressure of the constant pressure valve as P, wherein the pressure setting value after the first 10s pressurization of the constant pressure valve is P + L, the pressure setting value after the second 10s pressurization is P +2L, the pressure setting value after the third 10s pressurization is P +3L, …, and the pressure setting value after the last 10s pressurization is P + nL and is equal to the pressurization target value M;

the PLC judges every 10s and judges whether the difference between the pressure measured by the pressure sensor A and the current corresponding pressure set value is less than or equal to the step length set value and is L;

if the step length set value is less than or equal to L, the pressure of the constant pressure valve is normal, the PLC automatically sets a pressure set value after the pressure of the constant pressure valve is increased for the next 10s until the pressure set value of the constant pressure valve is equal to the pressure increase target value M;

if the step length is larger than the set value L, the constant pressure valve is abnormal in work; if the pressure measured by the pressure sensor A is not less than or equal to the set step length value L after 30s, a function button for alarming the pressurization overtime on an operation interface of automatic flow operation software of the constant pressure valve of the upper computer prompts the pressurization overtime, closes the pressurization stop valve, stops the pressurization of the liquid oxygen tank, and takes measures, namely, the constant pressure valve and the pressurization pipeline are checked; if the pressure measured by the pressure sensor A is less than or equal to the step length set value and is L after 30s, the pressure of the constant pressure valve is gradually increased to the current corresponding pressure set value, the PLC automatically sets the pressure set value after the pressure of the constant pressure valve is increased for the next 10s until the pressure set value of the constant pressure valve is equal to the pressure increase target value M;

for example, in this embodiment, the target value of the pressurization of the constant pressure valve is 10MP, the step size setting value is 0.5MP, the initial pressure is OMP, the constant pressure valve performs pressurization every 10 seconds from OMP, the first pressure setting value is 0.5MP, the second pressure is 1MP, the third pressure is 1.5MP, …, and up to the pressurization of 10 MP;

if the constant pressure valve is pressurized to 3MP, the current pressure set value is 3MP, and if the pressure measured by the pressure sensor A is more than 2.5MP, the pressure is less than the step length set value by 0.5 MP; if the pressure increase is normal, the PLC automatically sets the next pressure set value to be 3.5MP to the pressure setting valve; if the pressure measured by the pressure sensor A is below 2.5 and is greater than 0.5MP, the constant pressure valve is abnormal in operation;

(4) when the pressure set value of the constant pressure valve is equal to the pressurization target value M, the PLC judges whether the pressure of the liquid oxygen tank meets the set value or not through the pressure measured by the pressure sensor C, if yes, the execution of the automatic pressurization program is finished, and the automatic pressurization is finished through a function button for stopping pressurization on an operation interface of automatic flow operation software of the constant pressure valve of the upper computer.

Wherein, the operator can stop the automatic pressurization program at any time through a function button for stopping pressurization on the operation interface of the automatic flow operation software of the constant pressure valve;

an operator can intervene in the pressurization process according to the pressurization condition of the liquid oxygen tank, namely, in the pressurization process, the valve can be operated through the PLC, the automatic pressurization program is stopped, and the state of the valve which is not operated is kept, namely, the constant pressure valve is normally opened and the pressurization cutoff valve is normally closed;

and a pressure-increasing set value input box on an operation interface of the automatic flow operation software of the constant pressure valve of the upper computer can be manually set, namely, the pressure set value of the constant pressure valve is manually input every 10s until the pressure set value is equal to a pressure-increasing target value.

In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.