CN115628322A

CN115628322A - Novel fusible alloy plug and intelligent control method thereof

Info

Publication number: CN115628322A
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: 2023-01-20
Anticipated expiration: 2042-10-26
Also published as: CN115628322B

Abstract

The invention discloses a novel fusible alloy plug and an intelligent control method thereof, wherein a temperature sensor and a heating coil are sleeved on the periphery of a connecting shaft I of the fusible alloy plug, one end of the fusible alloy plug is connected with an emergency cut-off valve through a bolt, and the other end of the fusible alloy plug 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 the flame-retardant cable; the control panel is connected with the remote controller through a wireless radio frequency network. When an emergency occurs, a remote emergency cut-off valve closing program is started through a remote controller, the control panel controls the output power of the heating coil through a built-in fuzzy control algorithm, so that the fusible alloy is quickly melted at the melting point temperature, the connecting shaft I is separated from the connecting shaft II, and the emergency cut-off valve is automatically closed; meanwhile, the control panel sends the data to the cloud server, and support is provided for emergency disposal. Has the advantages of safety, reliability and intelligent control.

Description

Novel fusible alloy plug and intelligent control method thereof

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 transport vehicle and an intelligent control method thereof.

Background

The fusible alloy plug (also called fusible plug) is an important component in an emergency cut-off device of a dangerous chemical tank car and is commonly used for mechanical type emergency cut-off 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 plug pin, when a fire disaster occurs outside or the temperature rises sharply, the fusible alloy in the device is melted rapidly after the temperature reaches the melting point of the fusible alloy, and the emergency cut-off valve is closed automatically to prevent the medium in the tank car from leaking.

When the dangerous medium leaks in a large area due to the conditions of joint falling and the like in the loading and unloading process of the dangerous chemical tank car, personnel generally cannot close to the vehicle to manually close the emergency cut-off valve. Aiming at the situation, the applicant designs a remote control device (patent number: ZL 202121595660.0) of an emergency cut-off valve of a hazardous chemical transport vehicle in 2021, and controls a heating coil to heat an easily-fused gold plug through a mobile phone end, and the heating is stopped when the easily-fused gold plug is heated and cut off, so that the automatic closing of the emergency cut-off valve is realized. The device finds the aspects needing improvement in the engineering popularization process: (1) The energy input control of the heating coil is simple, the energy utilization efficiency and time in the heating process are not optimized, the temperature overshoot phenomenon exists on the surface of the coil, and the potential safety hazard possibly exists when the instantaneous temperature of the heating coil is too high; (2) The influence of the tightness degree of the steel wire rope on the fusing sensitivity of the fusible plug and the opening degree of the emergency cut-off valve is not considered, and a control method reasonable to the tension of the steel wire rope is lacked. (3) The field needs the cell phone APP to control, but the strict filling place is required to prohibit people from entering with the cell phone, so the use of the device is limited.

Disclosure of Invention

In order to overcome the above problems in the prior art, the present invention provides a novel fusible alloy plug and an intelligent control method thereof, wherein the fusible alloy plug can realize three functions: when fire disaster occurs outside or the temperature rises sharply, the fusible alloy in the device is melted after reaching the melting point temperature, and the emergency cut-off valve is closed automatically; 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 a remote controller to prompt personnel to close the valve and prevent the emergency cut-off valve from not being closed when the vehicle runs; when the condition such as take over and drop takes place to lead to the fact the large tracts of land to leak when dangerous chemicals transport vechicle loading and unloading material in-process, personnel though can't be close the tank car, but can remote operation control panel, through built-in intelligent algorithm, safe quick fusing fusible plug realizes emergency cut-off valve's quick shutdown. The intelligent control system has the characteristics of scientific design, safety, reliability and intelligent control.

In order to achieve the purpose, the 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 a control board in the explosion-proof box through a flame-retardant cable; the control panel is connected with the remote controller through a wireless radio frequency network;

i outside cover of connecting axle is equipped with temperature sensor and heating coil, and the heating coil outside is helical structure stainless steel strip, and the heater strip has been inlayed to inside, and 16mm in the coil internal diameter, the cross-section is 4.2 × 2.2mm rectangle.

The control panel regularly monitors the numerical value of the tension sensor and switches between the working state and the silent state. When the monitoring value is larger than the set threshold value for two times continuously, the control panel is in a working state, and the functions of fusible alloy plug temperature acquisition, coil heating, field data uploading, remote controller communication and the like can be realized. When the pulling force is outside the optimal interval, the field personnel is automatically prompted to adjust the reset handle, so that the fusible alloy plug is in the optimal working state, and the emergency cut-off valve can be quickly closed when an emergency occurs; when the tension monitoring value is less than the set threshold value twice continuously, the control panel is in a silent state, and the tension sensor value is only monitored periodically.

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 greater than the set threshold value, the remote controller automatically gives an alarm to remind personnel to close the emergency cut-off valve.

When an emergency occurs, a remote emergency cut-off valve closing program is started through a remote controller, the control panel controls the output power of the heating coil through a built-in fuzzy control algorithm, the fusible alloy is quickly melted after reaching the melting point temperature, the connecting shaft I is separated from the connecting shaft II, and the emergency cut-off valve is automatically closed. Meanwhile, the control panel sends the data to the cloud server, and support is provided for emergency disposal. In order 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 domain, and reading a controllable output power range [ c, d ] of the heating coil as an output basic domain. Inputting basic discourse domain to adjust according to different requirements of vehicle, medium and temperature deviation range; the output basic discourse domain is set according to different heating coil parameters.

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

(3) And adopting a triangular membership function to represent the membership relationship between elements (-n, n) of input and output vectors, and establishing an input membership and output membership relationship matrix. The matrix elements xij are shown below.

(4) And after the input membership matrix row vectors are inverted, intersection sets (minimum value of elements) are obtained one by one with corresponding output membership matrix row vectors, and then the obtained matrix union sets (maximum value of elements) are obtained to establish a fuzzy relation matrix R.

(5) Reading the real-time temperature of the fusible alloy plug through a temperature sensor, calculating the real-time temperature with a preset target temperature to obtain a temperature deviation t, and obtaining the temperature deviation t through the calculation

And mapping the temperature deviation t to a fuzzy subset theory domain value { -n, n }.

(6) If e is larger than n, the current temperature is low, the deviation with the target temperature is large, the coil is output at the maximum power, intelligent fuzzy control is not adopted in the heating process, namely p = d, and the steps (5) and (6) are repeated; if e is less than or equal to n, starting fuzzy control in the heating process, and entering the step (7).

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

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

Namely, it is

Using the gravity center method to output vector

The inner element is operated to obtain a fuzzy value m of the output control quantity, i.e.

(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, namely

(10) And (5) repeating the steps (5) to (9), and finishing the control algorithm when the temperature deviation t is less than or equal to 0.1 ℃ or the numerical value of the tension sensor is instantly reduced to 0 for 3 times continuously, 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, so that the power consumption is saved, and the endurance time of the device is prolonged; when the vehicle speed exceeds 5km/h and the emergency cut-off valve is not closed, automatically alarming and reminding personnel 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 guaranteed.

(2) Is safe and reliable. According to the invention, the temperature overshoot phenomenon in the heating process of the fusible alloy plug is effectively controlled through an intelligent algorithm, 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, and the contradiction that the mobile phone cannot be used in a tank car filling place due to the fact that the mobile phone is adopted for remote control in the originally granted patent ZL202121595660.0 of the team is overcome.

(3) And 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 of ensuring that the surface temperature does not exceed the ignition temperature of the medium. Meanwhile, the minimum electric quantity is consumed in the heating process, and the endurance time of the device is effectively prolonged.

Drawings

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

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

FIG. 3 is a control flow chart;

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

Detailed Description

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

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 a 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 board 12 in an explosion-proof box 10 through a flame-retardant cable 9; the control panel is connected with a 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 heating coil is helical structure stainless steel strip, and inside has inlayed the heating resistor silk. The coil has an inner diameter of 16mm and a cross section of a rectangle of 4.2X 2.2mm, and the heating power of the coil is 600W for 1 meter.

The inventor measures the tensile force of the steel wire rope of the mechanical vehicle emergency cut-off valve using the fusible alloy plug, and obtains the following results:

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

when the tensile force of the steel wire rope is greater than 22N, the valve starts to be opened;

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

when the steel wire rope pulling force was greater than 80N, the valve was in the open mode, but reset spring was in the overstretch state this moment, and long-term work under this state will influence the resilience performance of spring, and quick action emergency valve operational reliability is difficult to guarantee.

Therefore, for the mechanical vehicle emergency cut-off valve, the optimal interval of the steel wire rope tension F in the opening state is (F is more than or equal to 80N and less than or equal to 90N).

The control panel 12 periodically monitors the tension sensor values and switches between operating and quiescent states. When the monitoring value is larger than the set threshold (22N) for two times continuously, 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, field data uploading, remote controller communication and the like can be realized. When the pulling force is outside the optimal interval (F is more than or equal to 80N and less than or equal to 90N), the field personnel is automatically prompted to adjust the reset handle, so that the fusible alloy plug is in the optimal working state, and the emergency cut-off valve can be quickly closed when an emergency occurs; when the tension monitoring value is less than a set threshold value (22N) twice continuously, the emergency cut-off valve is closed, the control panel is in a silent state, the tension sensor value is only monitored periodically, and the monitoring frequency is 2 times/second.

When the GPS carried by the control panel 12 detects that the vehicle moving speed exceeds a set threshold (5 km/h) and the output value of the tension sensor 15 is greater than a set threshold (22N), an alarm is automatically sent out through a remote controller to remind personnel 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 temperature of the site environment is 25 ℃, the target temperature of the fusible alloy plug is 75 ℃, the temperature deviation range [ a, b ] = [ 20,20], the controllable output power range [ c, d ] = [0,242] watt is formed by the heating coil, and 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, the control panel controls the output power of the heating coil through a built-in fuzzy control algorithm, so that the fusible alloy is quickly melted to reach the melting point temperature, the connecting shaft I1 is separated from the connecting shaft II 4, and the emergency cut-off valve is automatically closed. Meanwhile, the control panel sends the data to the cloud server, and support is provided for emergency disposal. The control algorithm is implemented according to the following steps:

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

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

(3) The triangular membership function is adopted to represent the membership degree relation between input vectors and output vectors (-n, n), and an input membership degree relation table and an output membership degree relation table are established and are shown in tables 1 and 2.

TABLE 1 input membership degree relationship Table

TABLE 2 output membership degree relationship table

(4) And establishing a fuzzy relation matrix R. The fuzzy rule is the core of the fuzzy control algorithm, when the temperature deviation is large, the deviation vector is input as PB after fuzzification, the actual temperature is much lower than the expected temperature, the fusible alloy needs to be heated by the maximum power at the moment, and therefore 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 the temperature is maintained by adopting medium power; when the negative temperature deviation is large, the actual temperature is higher than the target temperature, and the fusible plug is heated by using smaller power and maintains the temperature stability 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 sequentially inverted and then the intersection (the element takes the numerical value with small numerical value) is solved with the corresponding output membership vector, and finally the obtained matrix solving union set (the element takes the numerical value with large numerical value) is obtained to obtain the fuzzy relation matrix R.

The same can be obtained

(5) Assuming that the measured temperature of the current sensor is 45 ℃, calculating with a preset target temperature of 75 ℃ to obtain a temperature deviation t =30 ℃, and passing through

And if the domain value e =9 > 6 of the fuzzy subset of the temperature deviation is obtained, fuzzy control is not adopted at present, the heating coil is heated by adopting the maximum power, and the temperature of the sensor is read again. Assuming that the next time the sensor temperature is obtained is 66 ℃, the temperature deviation t =9 ℃, pass

A fuzzy subset discourse field value e =2.7 of the temperature deviation was obtained.

(6) And inquiring an input membership relation table through a fuzzy subset discourse domain value e =2.7 of the temperature deviation, wherein e in the table is an integer, and e =3 or e =2 can be taken. E =3 is taken because a larger value of e in the table indicates a larger temperature deviation, and the system will be heated with a larger power and with a shorter time. At this time, the membership degrees corresponding to PS and PM are both 0.5, and both can be used as input deviation vectors. At this time, the temperature deviation is large, and a deviation vector capable of outputting larger power is required to be selected according to the requirement, so that the deviation vector is selected as

(7) By means of deviation vectors

Operating with the fuzzy relation matrix R to obtain the output vector of the fuzzy controller

Namely, it is

Using the gravity center method to output vectors

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

(9) And (5) repeating the steps (5) to (8), rapidly heating the easily-fused gold 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 ℃ for 3 times continuously or the numerical value of the tension sensor is instantly reduced to 0, the fusible alloy plug connecting shaft I1 and the connecting shaft II 4 are separated, the emergency cut-off valve is closed, the control algorithm is finished, and the coil stops heating.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A novel fusible alloy plug is characterized by comprising a connecting shaft I (1), a connecting shaft II (4), 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);

a temperature sensor and a heating coil are sleeved outside the connecting shaft I, a stainless steel strip with a spiral structure is arranged outside the heating coil, and a heating wire is embedded inside the heating coil;

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

2. The intelligent control method of the novel fusible alloy plug as claimed in claim 1, wherein the control board periodically monitors the value of the tension sensor and switches between a working state and a silent state; when the monitoring values are larger than the set threshold value continuously twice, the control panel is in a working state, and the functions of fusible alloy plug temperature acquisition, coil heating, field data uploading and communication with a remote controller can be realized; when the pulling force is outside the optimal interval, the field personnel is automatically prompted to adjust the reset handle, so that the fusible alloy plug is in the optimal working state, and the emergency cut-off valve can be quickly closed when an emergency occurs; when the tension monitoring value is less than the set threshold value twice continuously, the control panel is in a silent state, and the tension sensor value is only monitored periodically.

3. An intelligent control method for a novel fusible alloy plug as claimed in claim 2, wherein when a GPS carried by the control panel detects that the vehicle speed exceeds a set threshold and the output value of the tension sensor is greater than the set threshold, an alarm is automatically sent out through a remote controller to remind personnel to close the emergency cut-off valve.

4. The intelligent control method of the novel fusible alloy plug is characterized in that when an emergency occurs, a remote emergency cut-off valve closing program is started through a remote controller, the control panel controls the output power of the heating coil through a built-in fuzzy control algorithm, so that the fusible alloy is quickly melted to reach the melting point temperature, and the connecting shaft I is separated from the connecting shaft II to realize the automatic closing of the emergency cut-off valve; meanwhile, the control panel sends the data to the cloud server, and support is provided for emergency disposal.

5. The intelligent control method of the novel fusible alloy plug as claimed in claim 4, wherein the fuzzy control algorithm is implemented by the following steps:

(1) Reading a preset temperature deviation range [ a, b ] as an input basic domain, and reading a controllable output power range [ c, d ] of the heating coil as an output basic domain; inputting basic discourse domain to adjust according to different requirements of vehicles, media, temperature deviation range and the like; setting an output basic discourse domain according to different heating coil parameters;

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

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

(3) Adopting a triangular membership function to represent the membership relation between elements of input and output vectors (-n, n), and establishing an input membership and output membership relation matrix; matrix element x _ij As shown in the following formula:

(4) And (3) after the input membership matrix row vectors are inverted, solving intersection (taking element minimum) with corresponding output membership matrix row vectors one by one, then solving union set (taking element maximum) of the obtained matrixes, and establishing a fuzzy relation matrix R:

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

(6) If e is larger than n, the current temperature is low, the deviation with the target temperature is large, the coil is output at the maximum power, intelligent fuzzy control is not adopted in the heating process, namely p = d, and the steps (5) and (6) are repeated; if e is less than or equal to n, starting fuzzy control in the heating process, and entering the step (7);

Namely, it is

Using the gravity center method to output vector

6. The intelligent control method of the novel fusible alloy plug as claimed in claim 4, wherein the temperature of the heating coil does not exceed a preset maximum temperature for safety.