CN115628322B

CN115628322B - Intelligent control method for fusible alloy plug

Info

Publication number: CN115628322B
Application number: CN202211317992.1A
Authority: CN
Inventors: 业成; 张伯君; 文耀华; 武晓光; 于敬利; 方学锋; 黄强; 孙艾; 周楠
Original assignee: Nanjing Boiler & Pressure Vessel Supervision And Inspection Institute
Current assignee: Nanjing Boiler & Pressure Vessel Supervision And Inspection Institute
Priority date: 2022-10-26
Filing date: 2022-10-26
Publication date: 2023-05-16
Anticipated expiration: 2042-10-26
Also published as: CN115628322A

Abstract

The invention discloses a novel fusible alloy plug and an intelligent control method thereof, wherein the periphery of a connecting shaft I of the fusible alloy plug is sleeved with a temperature sensor and a heating coil, one end of the connecting shaft I is connected with an emergency cut-off valve through a bolt, and the other end of the connecting shaft I is connected with a connecting shaft II through fusible alloy; the connecting shaft II is connected with the tension sensor through threads; the tension sensor is connected with the reset handle. The temperature sensor, the tension sensor and the heating coil are connected with the control panel through flame-retardant cables; the control panel is connected with the remote controller through a wireless radio frequency network. When an emergency occurs, a remote control is used for starting a program for remotely closing the emergency cut-off valve, the control panel controls the output power of the heating coil through a built-in fuzzy control algorithm, so that the fusible alloy quickly reaches the melting point temperature to be melted, and the connecting shaft I and the connecting shaft II are separated, thereby realizing the automatic closing of the emergency cut-off valve; meanwhile, the control board sends data to the cloud server, and support is provided for emergency treatment. Has the advantages of safety, reliability and intelligent control.

Description

Intelligent control method for fusible alloy plug

Technical Field

The invention belongs to the technical field of automatic control, and particularly relates to a fusible alloy plug for an emergency cut-off valve of a hazardous chemical substance transport vehicle and an intelligent control method thereof.

Background

Fusible alloy plugs (also known as fusible plugs) are an important component in emergency cutting devices of dangerous chemical tank trucks and are commonly used for mechanical emergency cutting valves for vehicles. The two ends of the fusible plug are respectively connected with the reset handle and the emergency cut-off valve through the steel wire rope and the bolt, when an external fire disaster occurs or the temperature rises sharply, the fusible alloy in the device is melted rapidly after the temperature reaches the melting point, and the emergency cut-off valve is automatically closed to prevent the medium in the tank car from leaking.

When the dangerous medium leaks in a large area due to the fact that connectors fall off and the like in the loading and unloading process of the dangerous chemical tank truck, personnel cannot manually close the emergency cut-off valve close to the vehicle. In order to solve the problem, the applicant designs a remote control device (patent number ZL 202121595660.0) for an emergency cut-off valve of a hazardous chemical substance transport vehicle in 2021, and the remote control device is used for controlling a heating coil to heat a fusible alloy plug through a mobile phone end, and stopping heating after the fusible alloy plug is heated and disconnected, so that the emergency cut-off valve is automatically closed. The device finds the aspect needing improvement in the engineering popularization process: (1) The energy input control of the heating coil is simpler, the energy utilization efficiency and time in the heating process are not optimized, the surface of the coil has the temperature overshoot phenomenon, and the instantaneous temperature of the heating coil is too high, so that the potential safety hazard can be caused; (2) The influence of the tightness degree of the steel wire rope on the fuse melting sensitivity and the opening degree of the emergency cut-off valve is not considered, and a reasonable control method for the tension of the steel wire rope is lacked. (3) The mobile phone APP is required to control on site, but strict filling places are required to prohibit people from carrying mobile phones in, so that the device is limited in use.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention aims to provide a novel fusible alloy plug and an intelligent control method thereof, wherein the fusible alloy plug can realize three functions: when fire disaster occurs or the temperature rises sharply, the fusible alloy in the device melts after reaching the melting point temperature, and the emergency cut-off valve is automatically closed; the control panel acquires the working state of the emergency cut-off valve through the tension sensor, and when the vehicle speed exceeds a set value and the emergency cut-off valve is not closed, the control panel sends alarm information through the remote controller to prompt personnel to close the valve so as to prevent the emergency cut-off valve from being closed when the vehicle runs; when conditions such as take over drop occur in the loading and unloading process of the hazardous chemical substance transport vehicle to cause large-area leakage, personnel can not approach the tank car, but can remote operation control panel, through built-in intelligent algorithm, safe and quick fusing is easy to fuse, and quick closing of the emergency cut-off valve is realized. The intelligent control system has the characteristics of scientific design, safety, reliability and intelligent control.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

a novel fusible alloy plug comprises a connecting shaft I, a connecting shaft II, fusible alloy, a temperature sensor, a tension sensor and a heating coil;

one end of the connecting shaft I is connected with the emergency cut-off valve through a bolt, and the other end of the connecting shaft I is connected with the connecting shaft II through fusible alloy; the connecting shaft II is connected with the tension sensor through threads; the tension sensor is connected with the reset handle through a steel wire rope; the temperature sensor, the tension sensor and the heating coil are connected with the control board in the explosion-proof box through flame-retardant cables; the control panel is connected with the remote controller through a wireless radio frequency network;

the outside of the connecting shaft I is sleeved with a temperature sensor and a heating coil, the outside of the heating coil is a stainless steel bar with a spiral structure, the inside of the heating coil is embedded with a heating wire, the inner diameter of the coil is 16mm, and the section of the coil is 4.2 x 2.2mm rectangle.

The control board monitors the value of the tension sensor regularly and switches between working and silence states. When the continuous two monitoring values are larger than the set threshold, the control panel is in a working state, and the functions of temperature acquisition of the fusible alloy plug, coil heating, on-site data uploading, communication with a remote controller and the like can be realized. When the tensile force is out of the optimal interval, the on-site personnel is automatically prompted to adjust the reset handle, so that the fusible alloy plug is in an optimal working state, and the emergency cut-off valve can be quickly closed when an emergency occurs; when the tension monitoring value is smaller than the set threshold value twice in succession, the control panel is in a silent state, and only the tension sensor value is monitored periodically.

When the GPS carried by the control panel detects that the movement speed of the vehicle exceeds a set threshold value and the output value of the tension sensor is larger than the set threshold value, an alarm is automatically sent out through the remote controller, and a person is reminded to close the emergency cut-off valve.

When an emergency occurs, a remote control is used for starting a program for remotely closing the emergency cut-off valve, the control panel controls the output power of the heating coil through a built-in fuzzy control algorithm, so that the fusible alloy quickly reaches the melting point temperature to be melted, and the connecting shaft I and the connecting shaft II are separated, thereby realizing the automatic closing of the emergency cut-off valve. Meanwhile, the control board sends data to the cloud server, and support is provided for emergency treatment. To ensure safety, the temperature of the heating coil does not exceed a preset maximum temperature. The control algorithm is implemented according to the following steps:

(1) And reading a preset temperature deviation range [ a, b ] as an input basic theory domain, and reading a heating coil controllable output power range [ c, d ] as an output basic theory domain. Inputting basic domains to adjust according to different requirements of vehicles, media, temperature deviation ranges and the like; the output basic domain is set according to different heating coil parameters.

(2) The fuzzy sets of input and output are set to { NB, NM, NS, O, PS, PM, PB }, NB represents negative big, NM represents negative small, O represents zero, PS represents positive small, PM represents medium, PB represents positive big. The fuzzy subset argument of the input and output is { -n, n } (n is a positive integer).

(3) And (3) representing the membership relation of each element of the input vector and the output vector between (-n, n) by adopting a triangle membership function, and establishing an input membership and output membership relation matrix. The matrix element xij is shown in the following formula.

(4) After the input membership matrix row vectors are transposed, intersection sets are calculated one by one (element minimum value is taken) with corresponding output membership matrix row vectors, and then the obtained matrices are combined (element maximum value is taken), so that a fuzzy relation matrix R is established.

(5) The real-time temperature of the fusible alloy plug is read through a temperature sensor, and is calculated with a preset target temperature to obtain a temperature deviation t, and the temperature deviation t is obtained through

The temperature deviation t is mapped to the fuzzy subset argument value { -n, n }.

(6) If e is larger than n, the current temperature is lower, the deviation from the target temperature is larger, the coil outputs at the maximum power, the heating process does not adopt intelligent fuzzy control, namely, p=d, and the steps (5) and (6) are repeated; if e is less than or equal to n, the heating process starts to carry out fuzzy control, and the step (7) is carried out.

(7) Inquiring an input membership relation table through fuzzy subset argument threshold e of temperature deviation to obtain a deviation vector under the current temperature deviation

(8) Obtaining an output vector of the fuzzy controller through the operation of the deviation vector and the fuzzy relation matrix R

I.e. < ->

The gravity center method is adopted to output vector->

The internal element is operated to obtain the fuzzy value m of the output control quantity, namely +.>

(9) Calculating the fuzzy value u of the output control quantity to obtain the power output value of the heating coil under the current temperature deviation condition, namely

(10) Repeating the steps (5) - (9), continuously cooling the coil 3 times when the temperature deviation t is less than or equal to 0.1 ℃ or the value of the tension sensor is instantaneously reduced to 0, ending the control algorithm, and stopping heating the coil.

The invention has the advantages and positive effects that:

(1) The design is scientific. According to the invention, the tension sensor is added on the basis of the existing fusible alloy plug, the control panel is switched between a normal working state and a silent state according to the tension condition of the steel wire rope, the electric quantity consumption is saved, and the endurance time of the device is prolonged; when the speed of the vehicle exceeds 5km/h and the emergency cut-off valve is not closed, automatically alarming and reminding a person to close the emergency cut-off valve; when the emergency cut-off valve is opened and the tension of the steel wire rope is too large or too small, personnel can be reminded to adjust the tightness of the steel wire, and the working reliability of the emergency cut-off valve is ensured.

(2) Is safe and reliable. According to the invention, through an intelligent algorithm, the temperature overshoot phenomenon in the heating process of the fusible alloy plug is effectively controlled, the surface temperature of the fusible alloy plug is strictly controlled within the set maximum allowable temperature, and the use safety is effectively ensured; meanwhile, the remote control is realized through the remote controller, so that the contradiction that the original patent ZL202121595660.0 issued by the team adopts a mobile phone to carry out remote control and the filling place of the tank truck cannot use the mobile phone is overcome.

(3) And (5) controlling intelligence. The invention adopts a fuzzy control algorithm to realize intelligent control on the heating process of the fusible alloy plug, and the fusible alloy is melted in the shortest time under the condition that the surface temperature is ensured not to exceed the ignition temperature of the medium. Meanwhile, the heating process consumes the minimum electric quantity, so that the endurance time of the device is effectively prolonged.

Drawings

FIG. 1 is a schematic diagram of a novel fusible alloy plug;

FIG. 2 is a schematic illustration of a fusible alloy plug connection;

FIG. 3 is a control flow diagram;

in the figure, 1, connecting shaft I, 2, heating coil, 3, temperature sensor, 4, connecting shaft II, 5, tension sensor, 6, fusible alloy, 7, reset handle, 8, wire rope, 9, flame-retardant cable, 10, explosion-proof case, 11, power, 12, control panel, 13, remote controller, 14, emergency cut-off valve.

Detailed Description

The invention will be further described in detail below with reference to the attached drawings and by means of specific embodiments.

Example 1

As shown in fig. 1 and 2, the novel fusible alloy plug comprises a connecting shaft I1, a connecting shaft II 4, a fusible alloy 6, a temperature sensor 3, a tension sensor 5 and a heating coil 2; one end of the connecting shaft I1 is connected with the emergency cut-off valve through a bolt, and the other end of the connecting shaft I is connected with the connecting shaft II 4 through fusible alloy; the connecting shaft II 4 is connected with the tension sensor 5 through threads; the tension sensor is connected with the reset handle 7 through a steel wire rope 8; the temperature sensor 3, the tension sensor 5 and the heating coil 2 are connected with a control panel 12 in the explosion-proof box 10 through a flame-retardant cable 9; the control panel is connected with the remote controller 13 through a wireless radio frequency network.

The outside cover of connecting axle I1 is equipped with temperature sensor 3 and heating coil 2, and the heating coil is spiral structure stainless steel strip, and inside has inlayed heating resistance wire. The coil had an inner diameter of 16mm and a cross section of 4.2X2.2 mm, and the heating power of the coil was 600W by a length of 1 meter.

The inventor measures the tension of a steel wire rope of the mechanical vehicle emergency stop valve by using the fusible alloy plug, and the following result is obtained:

when the tension of the steel wire rope is less than 22N, the valve is in a closed state;

when the tension of the steel wire rope is greater than 22N, the valve starts to open;

when the pulling force reaches 80N, the valve is completely opened;

when the tension of the steel wire rope is greater than 80N, the valve is in an open state, but the reset spring is in an overstretched state at the moment, the rebound resilience of the spring is influenced after the valve works in the overstretched state for a long time, and the working reliability of the emergency cut-off valve is difficult to guarantee.

Therefore, for a mechanical emergency shut-off valve for a vehicle, the optimum section of the wire rope pulling force F in the open state is (80 n+.f+.90n).

The control board 12 periodically monitors the value of the tension sensor and switches between active and silent states. When the continuous twice monitoring value is larger than the set threshold (22N), the emergency cut-off valve is opened, the control panel is in a working state, and the functions of fusible alloy plug temperature acquisition, coil heating, on-site data uploading, communication with a remote controller and the like can be realized. When the tensile force is out of the optimal interval (F is more than or equal to 80N is less than or equal to 90N), the on-site personnel is automatically prompted to adjust the reset handle, so that the fusible alloy plug is in an optimal working state, and the emergency cut-off valve can be quickly closed when an emergency occurs; when the tension monitoring value is continuously smaller than the set threshold value (22N) twice, the emergency cut-off valve is closed, the control panel is in a silent state, and only the tension sensor value is monitored periodically, and the monitoring frequency is 2 times/second.

When the GPS carried by the control panel 12 detects that the vehicle movement speed exceeds a set threshold (5 km/h) and the output value of the tension sensor 15 is larger than the set threshold (22N), an alarm is automatically sent out through the remote controller, and a person is reminded to close the emergency cut-off valve.

In this example, the heating coil had an inner diameter of 16mm and a length of 403mm, and the heating power was 242W. Assuming that the field environment temperature is 25 ℃, setting the target temperature of the fusible alloy plug to be 75 ℃, setting the temperature deviation range [ a, b ] = [ -20,20], and heating the controllable output power range [ c, d ] = [0,242] watt of the coil, wherein the maximum allowable temperature in the heating process is 95 ℃.

When an emergency occurs on site, a person starts a program for remotely closing the emergency cut-off valve through a remote controller, and the control panel controls the output power of the heating coil through a built-in fuzzy control algorithm, so that the fusible alloy quickly reaches the melting point temperature to be melted, and the connecting shaft I1 and the connecting shaft II 4 are separated, thereby realizing the automatic closing of the emergency cut-off valve. Meanwhile, the control board sends data to the cloud server, and support is provided for emergency treatment. The control algorithm is implemented according to the following steps:

(1) The preset temperature deviation range [ a, b ] = [ -20,20] is read as the basic domain of input, and the controllable output power range [ c, d ] = [0,242] of the heating coil is read as the basic domain of output.

(2) The fuzzy sets of input and output are set to be { NB, NM, NS, O, PS, PM, PB }, wherein NB represents negative big, NM represents negative medium, NS represents negative small, O represents zero, PS represents positive small, PM represents medium, PB represents positive big. The fuzzy subset argument of inputs and outputs is { -6, -5, -4, -3, -2, -1,0,1,2,3,4,5,6}.

(3) The membership relation between the input vector and the output vector (-n, n) is characterized by adopting a triangle membership function, and an input membership relation table and an output membership relation table are established as shown in tables 1 and 2.

TABLE 1 input membership table

TABLE 2 output membership table

(4) And establishing a fuzzy relation matrix R. The fuzzy rule is the core of a fuzzy control algorithm, when the temperature deviation is large, the input deviation vector is PB after blurring, which shows that the actual temperature is much lower than the expected temperature, and the fusible alloy needs to be heated by the maximum power at the moment, so that the output control quantity is PB; when the actual temperature is close to the expected temperature, the input temperature deviation is fuzzified to be O, and medium power is adopted to maintain the temperature; when the negative temperature deviation is large, the actual temperature is higher than the target temperature, and the fusible plug is heated by smaller power, so that the temperature stability is maintained through air heat dissipation. In the control process, the fuzzy rule is realized through a fuzzy relation matrix R. According to the rule, the input membership vector is transposed successively and then intersects with the corresponding output membership vector (the element takes the value smaller than the value), and finally the obtained matrix is union-found (the element takes the value larger than the value) to obtain the fuzzy relation matrix R.

Is available in the same way

(5) Assuming that the temperature measured by the current sensor is 45 ℃ and calculated with a preset target temperature of 75 ℃, obtaining a temperature deviation t=30 ℃, and obtaining a target temperature by

And obtaining a fuzzy subset argument threshold value e=9 > 6 of the temperature deviation, and not adopting fuzzy control at present, heating the heating coil by adopting maximum power, and reading the temperature of the sensor again. Assuming that the next time the sensor temperature is obtained at 66 ℃, the temperature deviation t=9℃, by +.>

Obtaining the temperatureFuzzy subset argument value of degree deviation e=2.7.

(6) And inquiring an input membership table through fuzzy subset argument threshold value e=2.7 of temperature deviation, wherein e in the table is an integer, and e=3 or e=2 can be taken. Since the larger the value of e in the table, the larger the temperature deviation, the more power will be used to heat the system, and the shorter the time will be, thus taking e=3. At this time, the membership degrees corresponding to PS and PM are both 0.5, and both the membership degrees can be used as input deviation vectors. At this time, the temperature deviation is larger, and a deviation vector with higher power can be output according to the requirement, so the deviation vector is taken as

(7) By means of a deviation vector

Obtaining the output vector of the fuzzy controller by calculating with the fuzzy relation matrix R>

I.e.

The gravity center method is adopted for outputting vectors

The internal element is operated to obtain the fuzzy value m of the output control quantity, namely

(8) Calculating the fuzzy value m of the output control quantity to obtain the power output value of the heating coil under the current temperature deviation condition, namely

A tile.

(9) Repeating the steps (5) - (8), rapidly heating the fusible alloy plug, and ensuring that the heating temperature does not exceed the set temperature. When the temperature deviation t is less than or equal to 0.1 ℃ or the value of the tension sensor is instantaneously reduced to 0 continuously for 3 times, the connecting shaft I1 and the connecting shaft II 4 of the fusible alloy plug for fusing the fusible alloy are separated, the emergency cut-off valve is closed, the control algorithm is finished, and the coil stops heating.

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.

Claims

1. An intelligent control method of a fusible alloy plug comprises a connecting shaft I (1), a connecting shaft II (4), a fusible alloy (6), a temperature sensor (3), a tension sensor (5) and a heating coil (2);

one end of the connecting shaft I is connected with the emergency cut-off valve through a bolt, and the other end of the connecting shaft I is connected with the connecting shaft II through fusible alloy; the connecting shaft II is connected with the tension sensor through threads; the tension sensor is connected with the reset handle through a steel wire rope (8);

the outer side of the connecting shaft I is sleeved with a temperature sensor and a heating coil, the outer part of the heating coil is a stainless steel bar with a spiral structure, and a heating wire is embedded in the heating coil;

the temperature sensor, the tension sensor and the heating coil are connected with the control board in the explosion-proof box through flame-retardant cables; the control panel is connected with the remote controller through a wireless radio frequency network;

the control board monitors the value of the tension sensor regularly and switches between working and silence states; when the continuous two monitoring values are larger than the set threshold, the control panel is in a working state, so that the functions of temperature acquisition of the fusible alloy plug, coil heating, on-site data uploading and communication with a remote controller can be realized; when the tensile force is out of the optimal interval, the on-site personnel is automatically prompted to adjust the reset handle, so that the fusible alloy plug is in an optimal working state, and the emergency cut-off valve can be quickly closed when an emergency occurs; when the tension monitoring value is smaller than the set threshold value twice in succession, the control panel is in a silent state, and only the tension sensor value is monitored periodically.

2. The intelligent control method of the fusible alloy plug according to claim 1, wherein when the GPS carried by the control panel detects that the vehicle movement speed exceeds a set threshold value and the output value of the tension sensor is larger than the set threshold value, an alarm is automatically sent out through the remote controller to remind a person to close the emergency cut-off valve.

3. The intelligent control method of the fusible alloy plug according to claim 1, wherein when an emergency occurs, a remote control is used for starting a program for remotely closing an emergency shut-off valve, a control panel controls the output power of a heating coil through a built-in fuzzy control algorithm, so that the fusible alloy is quickly melted at the melting point temperature, and a connecting shaft I and a connecting shaft II are separated, thereby realizing the automatic closing of the emergency shut-off valve; meanwhile, the control board sends data to the cloud server, and support is provided for emergency treatment.

4. The intelligent control method of the fusible alloy plug according to claim 3, wherein the fuzzy control algorithm is implemented according to the following steps:

(1) Reading a preset temperature deviation range [ a, b ] as an input basic theory domain, and reading a heating coil controllable output power range [ c, d ] as an output basic theory domain; inputting basic domains to adjust according to different vehicle, medium and temperature deviation range requirements; the output basic domain is set according to different heating coil parameters;

(2) Setting fuzzy sets of input and output as { NB, NM, NS, O, PS, PM, PB }, NB representing negative big, NM representing negative medium, NS representing negative small, O representing zero, PS representing positive small, PM representing medium, PB representing positive big;

the fuzzy subset argument of input and output is { -n, n } (n is a positive integer);

(3) A triangular membership function is adopted to represent membership relations between elements (-n, n) of the input vector and the output vector, and an input membership relation matrix and an output membership relation matrix are established; matrix element x _ij The following formula is shown:

(4) After the input membership matrix row vectors are transposed, intersection sets are calculated one by one (element minimum value is taken) with corresponding output membership matrix row vectors, then the obtained matrix is calculated in a union mode (element maximum value is taken), and a fuzzy relation matrix R is established:

Mapping the temperature deviation t to a fuzzy subset argument threshold value { -n, n };

(6) If e is larger than n, the current temperature is lower, the deviation from the target temperature is larger, the coil outputs at the maximum power, the heating process does not adopt intelligent fuzzy control, namely, p=d, and the steps (5) and (6) are repeated; if e is less than or equal to n, the heating process starts to carry out fuzzy control, and the step (7) is carried out;

I.e. < ->

The gravity center method is adopted to output vector->

5. A method of intelligent control of a fusible alloy plug in accordance with claim 3, wherein the temperature of the heating coil does not exceed a preset maximum temperature for safety.