PLC-based full-automatic safe feeding system for chemical production

Abstract

The invention relates to the technical field of chemical industry automation control, in particular to a PLC-based chemical industry production full-automatic safety feeding system, which comprises a control mechanism, a PLC control mechanism, a PLC control mechanism, a PLC control mechanism and a PLC control mechanism, an interaction mechanism; the detection mechanism comprises a temperature sensor and a gravity sensor; the executing mechanism comprises a feeding valve M1, a feeding valve M2 and a safety normally-closed electromagnetic valve, the opening degree of the feeding valve M1 and the opening degree of the feeding valve M2 are both controlled by the expansion module, the feeding valve M1 and the feeding valve M2 are used for accurately controlling the material flow, and the safety normally-closed electromagnetic valve is used for emergently cutting off a passage during power failure; and the protection mechanism comprises an intermediate relay. According to the invention, the feeding valve M1, the feeding valve M2 and the safety normally-closed electromagnetic valve are connected in series, so that a more automatic and intelligent stopping mode during overtemperature and overpressure is realized, and feeding can be stopped without controlling the feeding valves.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical automation control, and more specifically, to a fully automatic safety feeding system for chemical production based on PLC. Background Art

[0002] In the process of chemical production, the accurate feeding and safety control of materials are key links to ensure production efficiency and safety; traditional chemical feeding systems often rely on manual operation or semi-automatic control, and there are the following technical bottlenecks: firstly, the control accuracy is insufficient, and it is difficult to achieve precise adjustment of material flow through manual operation or simple valve control, which easily leads to ratio deviation and affects product quality; secondly, the safety protection is lacking, and there is no real-time environmental monitoring and emergency cut-off mechanism, and it cannot respond quickly under sudden working conditions, and there are risks of material leakage, equipment damage and even safety accidents such as over-temperature; then, the degree of automation is low, and parameter setting and system monitoring rely on manual intervention, and multi-parameter linkage control and automatic execution of preset processes cannot be achieved, and the production efficiency is limited.

[0003] For example, the patent with the publication number CN222388978U discloses a feeding system, including a feeding box and a feeding device. Among them, the bottom of the feeding box is provided with a discharge port, and a feeding channel and a plurality of separated material storage rooms are arranged inside the feeding box; the feeding channel is inclined downward and communicated with the discharge port; communication ports are arranged between the plurality of material storage rooms and the feeding channel, and are inclined downward in the direction from far to near the feeding channel; the feeding device is located between the feeding port and the discharge port, and is used for receiving the materials discharged from the feeding port and transferring them to the discharge port; it also includes a closing member, and the closing member is used for closing and opening the plurality of communication ports.

[0004] The above feeding system improves the smoothness and safety of material feeding, but there is no real-time monitoring, precise control and multiple safety protections, and it cannot meet the requirements of high precision, high safety and high automation in chemical production. Summary of the Invention

[0005] The purpose of the present invention is to provide a fully automatic safety feeding system for chemical production based on PLC to solve the problems raised in the above background art.

[0006] To achieve the solution of the above technical problems, the purpose of the present invention is to provide a fully automatic safety feeding system for chemical production based on PLC, including:

[0007] A control mechanism, including a main control module and an expansion module connected by signals. The model of the main control module is Siemens S7 200 SMART, and the model of the expansion module is Siemens AM06 expansion module. The main control module and the expansion module are used for receiving various parameters and outputting control signals;

[0008] An interaction mechanism, the model of the interaction mechanism is a SMART IE 700V3 touch screen, the interaction mechanism is signal-connected to the main control module, and the interaction mechanism is used to control parameters and display the system status;

[0009] A detection mechanism, including a temperature sensor and a gravity sensor, both the temperature sensor and the gravity sensor are signal-connected to the expansion module, the temperature sensor is used to collect the ambient temperature in real time, and the gravity sensor is used to collect the material weight in real time;

[0010] An execution mechanism, including a feed valve M1, a feed valve M2 and a normally closed solenoid valve for insurance, the opening degrees of the feed valve M1 and the feed valve M2 are both controlled by the expansion module, the feed valve M1 and the feed valve M2 are used to accurately control the material flow rate, and the normally closed solenoid valve for insurance is used to cut off the passage emergently when power is off;

[0011] A protection mechanism, including an intermediate relay, the switch of the intermediate relay is controlled by the main control module, the intermediate relay is connected in series with the normally closed solenoid valve for insurance, and the intermediate relay is used to trigger the normally closed solenoid valve for insurance when power is off.

[0012] As a further improvement of this technical solution, the opening degree control rate of the feed valve M1 and the feed valve M2 is 0.1%, and the mapping between the current signal and the valve opening degree is realized through the following formula:

[0013]

[0014] The main control module automatically converts and outputs a corresponding 4-20mA control signal according to the target opening degree value set by the interaction mechanism, and the current current value is output by the expansion module.

[0015] As a further improvement of this technical solution, the measuring range of the temperature sensor is 0-200°C. When the temperature measured by the temperature sensor is greater than the preset temperature threshold in the main control module, the main control module performs the following operations:

[0016] Output a 4mA signal to close the feed valve M1 and the feed valve M2;

[0017] Output a 24V pulse to trigger an alarm signal;

[0018] Lock the system operation permission until manual reset.

[0019] As a further improvement of this technical solution, the measuring range of the gravity sensor is 0-2 tons. When quantitative feeding is required, the main control module converts the target weight into a current set value through the following formula:

[0020]

[0021] The weight set value is obtained by the interaction mechanism. The maximum weight measurement value is the maximum range of the gravity sensor. The expansion module outputs the current current value according to the current set value to control the opening degrees of the feed valve M1 and the feed valve M2.

[0022] When the weight measurement value obtained by the gravity sensor is greater than the maximum range, the expansion module outputs a 4 mA signal to close the feed valve M1 and the feed valve M2.

[0023] As a further improvement of the technical solution, the normally closed solenoid valve for insurance is of the power-off locking type, which remains open when normally powered and closes immediately through spring reset when powered off.

[0024] As a further improvement of the technical solution, the coil voltage of the intermediate relay is 24 VDC. When the power supply is normal, the intermediate relay is attracted to maintain the normally closed solenoid valve for insurance open; when powered off, the intermediate relay loses power, and the normally closed solenoid valve for insurance is locked through spring reset, and the locked state is maintained until manual reset.

[0025] As a further improvement of the technical solution, the interaction mechanism has a built-in storage function, supports presetting multiple groups of feeding parameters, and can be quickly called and modified through the interface.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. In the fully automatic safe feeding system for chemical production based on PLC, a production system with two operating modes of automatic production or manual production controlled by a touch screen is realized, and multiple control of chemical production is achieved.

[0028] 2. In the fully automatic safe feeding system for chemical production based on PLC, through the series connection of the feed valve M1, the feed valve M2 and the normally closed solenoid valve for insurance, a more automatic and intelligent parking method is realized when the temperature is too high or the pressure is too high, and the feeding can be stopped without controlling the feed valve.

[0029] 3. In the fully automatic safe feeding system for chemical production based on PLC, in the event of a sudden power outage or a power outage caused by an accident, general automation systems will fail and manual valve closing is required. This system designs a production protection system that does not require manual valve closing and parking when powered off through the cooperation of the main control module digital quantity and the intermediate relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the circuit connection diagram of the present invention;

[0031] Figure 2 is the overall structure diagram of the present invention;

[0032] Figure 3 Program annotation diagram for the gravity sensor in the embodiment to read the pressure value;

[0033] Figure 4 Program annotation diagram for controlling the opening degree of the feed valve M1 in the embodiment;

[0034] Figure 5 Program annotation diagram for controlling the opening degree of the feed valve M2 in the embodiment;

[0035] Figure 6 Overall program annotation diagram for this embodiment;

[0036] The meanings of each mark in the figure are as follows: 1. Control mechanism; 10. Main control module; 11. Expansion module; 2. Interaction mechanism; 3. Detection mechanism; 30. Temperature sensor; 31. Gravity sensor; 4. Execution mechanism; 40. Feed valve M1; 41. Feed valve M2; 42. Insurance normally closed solenoid valve; 5. Protection mechanism; 50. Intermediate relay. Specific implementation manners

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0038] As Figures 1 - 6 shown, this embodiment provides a fully automatic safe feeding system for chemical production based on PLC, including:

[0039] Control mechanism 1, including a main control module 10 and an expansion module 11 connected by signals. The main control module 10 and the expansion module 11 communicate through the backplane bus to achieve millisecond-level response, ensuring the real-time performance and stability of the control signal. The model of the main control module 10 is Siemens S7 200 SMART, which has a built-in high-speed processor and digital / analog interfaces, and is responsible for receiving real-time data from the detection mechanism 3 and outputting control signals through the expansion module 11. The model of the expansion module 11 is Siemens AM06 expansion module, which provides additional analog input / output channels and supports the accurate conversion of 4-20mA current signals. The main control module 10 and the expansion module 11 are used to receive various parameters and output control signals, and the expansion module 11 includes an analog input / output module;

[0040] The interaction mechanism 2, with the model of SMART IE 700V3 touch screen, provides a human-machine interaction interface. Operators can set feeding parameters through the touch screen and monitor system parameters in real time. The touch screen is built-in with a storage chip that can save multiple groups of preset recipes, such as the feeding ratios of different materials, and supports one-key calling and dynamic modification. For example, when switching production batches, operators can directly select the corresponding recipe from the repository, and the system automatically adjusts the valve opening and weight threshold without re-entering parameters. The interaction mechanism 2 is signal-connected to the main control module 10 and is used to control parameters and display the system status;

[0041] The detection mechanism 3 includes a temperature sensor 30 and a gravity sensor 31. Both the temperature sensor 30 and the gravity sensor 31 are signal-connected to the expansion module 11. The temperature sensor 30 is used to collect the ambient temperature in real time, and the gravity sensor 31 is used to collect the material weight in real time. The temperature sensor 30 can adopt a PT100 platinum resistance with an accuracy of ±0.5°C, and the gravity sensor 31 can adopt a cantilever beam type weighing sensor;

[0042] The execution mechanism 4 includes a feed valve M140, a feed valve M241, and a normally closed solenoid valve 42 for insurance. The opening degrees of the feed valve M140 and the feed valve M241 are both controlled by the expansion module 11. The feed valve M140 and the feed valve M241 are used to precisely control the material flow rate. The normally closed solenoid valve 42 for insurance is used to cut off the passage emergently when power is off. The feed valve M140 and the feed valve M241 can be set to different sizes to facilitate precise feeding;

[0043] The protection mechanism 5 includes an intermediate relay 50. The intermediate relay 50 is controlled by the main control module 10 to switch on and off. The intermediate relay 50 is connected in series with the normally closed solenoid valve 42 for insurance, and the intermediate relay 50 is used to trigger the normally closed solenoid valve 42 for insurance when power is off.

[0044] In this embodiment, as Figure 4 、 Figure 5 and Figure 6 shown, through the S_RTI function block, the engineering value is reversely converted into an analog output. The input range is from 0.0 (fully closed) to 100 (fully open), which is converted to 5530 (4mA) to 27648 (20mA). Finally, the expansion module 11 outputs a 4 - 20mA signal to control the valve opening. The opening control rate of the feed valve M140 and the feed valve M241 is 0.1%, and the mapping between the current signal and the valve opening is realized through the following formula:

[0045]

[0046] The main control module 10 automatically calculates and outputs the corresponding 4 - 20mA control signal according to the target opening value set by the interaction mechanism 2, and the current value is output by the expansion module 11;

[0047] When the input signals of the feed valve M140 and the feed valve M241 are both 10 mA, then:

[0048]

[0049] The valve openings of the feed valve M140 and the feed valve M241 are both 37.5%.

[0050] Specifically, as Figure 6 shown, the range of the temperature sensor 30 is 0 - 200 °C. It is designed with a PT100 platinum resistance and its accuracy can reach ±0.5 °C, ensuring stable data acquisition in high-temperature environments. When the temperature measured by the temperature sensor 30 is greater than the preset temperature threshold in the main control module 10, the main control module 10 performs the following operations:

[0051] Output a 4 mA signal to close the feed valve M140 and the feed valve M241. 4 mA corresponds to the fully closed state of the valve, and the feed is directly cut off through the analog output of the expansion module 11 to prevent the material from decomposing or the reaction from getting out of control due to high temperature;

[0052] Output a 24 V pulse to trigger an alarm signal. The 24 V pulse signal drives an audible and visual alarm, including a buzzer and a warning light. At the same time, a red warning box pops up on the interface of the interaction mechanism 2, clearly indicating the over-temperature position and the severity level;

[0053] Lock the system operation permission until manual reset. To prevent secondary risks caused by misoperation or automatic recovery, the system will disable all control instructions, and only allow personnel with administrator privileges to perform a reset through physical buttons or password verification. This design complies with the "fail-safe" principle in chemical safety specifications.

[0054] Furthermore, as Figure 3 and Figure 6 shown, through the S_ITR function block, the analog input is standardized and converted. The gravity sensor 31 collects the weight signal. The original signal range is 5530 (4 mA) to 27648 (20 mA), corresponding to a range of 0 - 2 tons, and the output range is 0.0 to 2000.0. The range of the gravity sensor 31 is 0 - 2 tons. When quantitative feeding is required, the main control module 10 converts the target weight into a current set value through the following formula:

[0055]

[0056] The weight set value is obtained by the interaction mechanism 2. The maximum weight measurement is the maximum range of the gravity sensor 31. The expansion module 11 outputs the current current value according to the current set value to control the opening of the feed valve M140 and the feed valve M241;

[0057] If the set weight is 1 ton, then:

[0058]

[0059] The current set value in the main control module 10 is 12 mA. Then, the expansion module 11 outputs a 12 mA control signal to control the feed valve M140 and the feed valve M241.

[0060] When the weight measurement value obtained by the gravity sensor 31 is greater than the maximum range, the expansion module 11 outputs a 4 mA signal to close the feed valve M140 and the feed valve M241.

[0061] In addition, the normally-closed solenoid valve 42 of the insurance type is power-off locked. Its core is a dual-redundancy spring return structure. It remains open under normal power supply. When the electromagnetic coil is energized, it generates magnetic force to overcome the spring resistance. When powered off, it immediately closes through spring return. When the magnetic force disappears, the spring quickly resets within 300 ms to forcibly close the passage. It not only has a fast response speed but also can avoid the problem of locking failure caused by mechanical jamming of traditional solenoid valves. For example, in the event of a sudden power outage or a short circuit in the circuit, this valve can directly cut off the material flow independently of the PLC system, forming a double insurance and minimizing the leakage risk to the greatest extent.

[0062] It should be noted that the coil voltage of the intermediate relay 50 is 24 VDC, following the industrial low-voltage safety standard, which not only reduces the risk of electric shock but also is compatible with the power supply of the main control module 10. When the power supply is normal, the intermediate relay 50 is energized to maintain the opening of the normally-closed solenoid valve 42 of the insurance type, and its normally-open contact closes to provide a continuous passage for the normally-closed solenoid valve 42 of the insurance type. When powered off, the intermediate relay 50 loses power, and the contact immediately disconnects. The solenoid valve triggers the spring lock due to the loss of the holding current. The normally-closed solenoid valve 42 of the insurance type realizes locking through spring return, and the locked state is maintained until manual reset. The mechanical action time of the contact of the intermediate relay 50 is less than 50 ms, which cooperates with the locking of the normally-closed solenoid valve 42 of the insurance type to achieve a millisecond-level safety response. State maintenance: After locking, manual on-site reset is required to avoid potential hazards caused by automatic restart. For example, after the operator checks the cause of the failure and manually rotates the reset knob of the normally-closed solenoid valve 42 of the insurance type, the system can be powered on again to run.

[0063] It should be noted that the interaction mechanism 2 has a built-in storage function, supports presetting multiple groups of feeding parameters, can be quickly called and modified through the interface, and can also record historical alarm data and operation logs for easy retrospective analysis and analysis later. Users can intuitively complete the following operations:

[0064] Parameter call: Select a preset formula such as "batch A and catalyst feeding", and the system automatically loads the corresponding temperature, weight, and valve control parameters.

[0065] Dynamic modification: During the production process, if it is necessary to temporarily adjust the feeding amount, a new value can be directly entered on the interface, and the main control module 10 will perform real-time conversion and output an updated control signal.

[0066] Data export: Through the USB or Ethernet interface, export the recipe data and production records to an external server, support remote monitoring and big data analysis, and provide a basis for process optimization. This function is especially applicable to the flexible production scenarios of multiple varieties and small batches.

[0067] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A fully automatic safety feeding system for chemical production based on PLC, characterized in that, Comprising: A control mechanism (1), including a main control module (10) and an expansion module (11) connected by signals. The model of the main control module (10) is Siemens S7 200 SMART, and the model of the expansion module (11) is Siemens AM06 expansion module. The main control module (10) and the expansion module (11) are used to receive various parameters and output control signals; An interaction mechanism (2), the model of the interaction mechanism (2) is SMART IE 700V3 touch screen. The interaction mechanism (2) is signal-connected to the main control module (10), and the interaction mechanism (2) is used to control parameters and display the system status; A detection mechanism (3), including a temperature sensor (30) and a gravity sensor (31). The temperature sensor (30) and the gravity sensor (31) are both signal-connected to the expansion module (11). The temperature sensor (30) is used to collect the ambient temperature in real time, and the gravity sensor (31) is used to collect the material weight in real time; An execution mechanism (4), including a feed valve M1 (40), a feed valve M2 (41) and a safety normally closed solenoid valve (42). The opening degrees of the feed valve M1 (40) and the feed valve M2 (41) are controlled by the expansion module (11). The feed valve M1 (40) and the feed valve M2 (41) are used to accurately control the material flow rate, and the safety normally closed solenoid valve (42) is used to emergently cut off the passage when powered off; A protection mechanism (5), including an intermediate relay (50). The switch of the intermediate relay (50) is controlled by the main control module (10). The intermediate relay (50) is connected in series with the safety normally closed solenoid valve (42), and the intermediate relay (50) is used to trigger the safety normally closed solenoid valve (42) when powered off.

2. The fully automatic safe feeding system for chemical production based on PLC according to claim 1, wherein, The opening control rate of the feed valve M1 (40) and the feed valve M2 (41) is 0.1%, and the mapping between the current signal and the valve opening is realized by the following formula: The main control module (10) automatically converts and outputs a corresponding 4-20mA control signal according to the target opening value set by the interaction mechanism (2), and the current value is output by the expansion module (11).

3. The fully automatic safe feeding system for chemical production based on PLC according to claim 2, characterized in that, The range of the temperature sensor (30) is 0-200°C. When the temperature measured by the temperature sensor (30) is greater than the preset temperature threshold in the main control module (10), the main control module (10) performs the following operations: Output a 4mA signal to close the feed valve M1 (40) and the feed valve M2 (41); Output a 24V pulse to trigger an alarm signal; Lock the system operation permission until manual reset.

4. The fully automatic safe feeding system for chemical production based on PLC according to claim 2, characterized in that, The range of the gravity sensor (31) is 0-2 tons. When quantitative feeding is required, the main control module (10) converts the target weight into a current set value by the following formula: The weight set value is obtained by the interaction mechanism (2), the maximum weight measurement is the maximum range of the gravity sensor (31), and the expansion module (11) outputs the current value according to the current set value to control the opening degrees of the feed valve M1 (40) and the feed valve M2 (41). When the weight measurement value obtained by the gravity sensor (31) is greater than the maximum range, the expansion module (11) outputs a 4 mA signal to close the feed valve M1 (40) and the feed valve M2 (41).

5. The fully automatic safe feeding system for chemical production based on PLC according to claim 1, wherein: The normally closed solenoid valve (42) is of the power-off locking type. When it is normally powered, it remains open, and when the power is off, it closes immediately through spring resetting.

6. The fully automatic safe feeding system for chemical production based on PLC according to claim 5, wherein: The coil voltage of the intermediate relay (50) is 24 VDC. When the power supply is normal, the intermediate relay (50) is energized to maintain the opening of the normally closed solenoid valve (42). When the power is off, the intermediate relay (50) loses power, and the normally closed solenoid valve (42) is locked through spring resetting, and the locked state is maintained until manual resetting.

7. The fully automatic safe feeding system for chemical production based on PLC according to claim 1, characterized in that: The interaction mechanism (2) has a built-in storage function, supports presetting multiple groups of feeding parameters, and can be quickly called and modified through the interface.

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