Constant-temperature purging protection system of thermal infrared imager

Abstract

The invention discloses a thermal infrared imager constant-temperature purging protection system, which is characterized in that through the integrated design of a protective cover, a threading air passing pipe, a temperature sensor, a PLC (Programmable Logic Controller) and a regulating valve, the accurate constant-temperature control of a thermal imager and the efficient purging of a window are simultaneously realized by utilizing the same high-pressure air source, and a signal cable is synchronously cooled and protected. The system adopts a PID algorithm to dynamically adjust the opening degree of the valve, is combined with real-time monitoring of a human-computer interface, has the advantages of being high in integration level, low in operation and maintenance cost and high in measurement reliability, and is suitable for infrared detection application in high-temperature environments such as metallurgy and chemical engineering. High-pressure air flow is adjusted in real time through a PLC and a PID algorithm, the working environment temperature of the thermal imager is stabilized within a target range, temperature drift caused by high temperature is effectively avoided, and the temperature measurement precision and reliability are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of industrial monitoring equipment protection technology, specifically relating to a constant temperature purging protection system for infrared thermal imagers. Background Technology

[0002] Infrared thermal imagers generate thermal images by detecting the infrared radiation of target objects, and are widely used in industrial equipment condition monitoring (such as overheat detection of power equipment and temperature field monitoring of metallurgical furnaces) and security monitoring. However, when used in high-temperature environments (such as around metallurgical blast furnaces, near chemical reaction vessels, and at observation ports of high-temperature kilns), current infrared thermal imager protection systems have the following shortcomings: 1. Insufficient cooling capacity: Only the camera body is cooled, while the signal cables are not. Under prolonged high temperatures, the signal cables may age and break, leading to malfunctions.

[0003] 2. Low temperature control accuracy. The existing fixed airflow design cannot adapt to fluctuations in operating conditions, resulting in significant temperature fluctuations in the cavity and a decrease in the detection performance of the thermal imager. 3. Poor system integration: The temperature control and purging devices are designed separately, which occupies a large space and requires disassembly for maintenance, resulting in high complexity. To address the aforementioned issues, there is an urgent need to develop an integrated, low-energy-consumption, and high-precision protection system to meet the requirements for long-term stable operation in extreme industrial environments. Summary of the Invention

[0004] The purpose of this invention is to provide a constant temperature purge protection system for infrared thermal imagers. Through integrated design, it simultaneously achieves precise constant temperature control of the thermal imager and efficient purge of the viewing window, while providing synchronous cooling protection for the signal cables. This solves the problems of low integration, high maintenance costs, and insufficient temperature control accuracy of existing split-type solutions.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: An infrared thermal imager constant temperature purge protection system includes: The protective cover is equipped with a thermal imager and temperature sensor inside, and the front of the protective cover has a viewing window for infrared radiation transmission. The cable routing duct connects to the protective cover at one end and extends to the outside of the high-temperature zone at the other end. The cables of the thermal imager and temperature sensor are routed through the cable routing duct to the outside of the protective cover. An air inlet is also provided at the end of the cable routing duct. High-pressure air enters the protective cover through the air inlet and the cable routing duct, and the high-pressure air cools the thermal imager. The human-machine interface and PLC are located outside the high-temperature zone. The PLC is connected to the temperature sensor, the human-machine interface and the regulating valve respectively. The regulating valve is installed outside the air inlet of the wiring duct and is used to regulate the air intake. The gas nozzle is fixed above the window of the protective cover, with the jet direction facing the window. The air inside the protective cover is discharged through the gas nozzle. After being regulated by the regulating valve, the high-pressure air enters the wiring duct through the air inlet, flows through the protective cover to cool the thermal imager, and blows through the protective cover window through the gas nozzle; the temperature sensor signal is processed by the PLC and then controlled by PID calculation to control the opening of the regulating valve to achieve local temperature stability inside the protective cover.

[0006] Furthermore, the end of the duct extending to the outside of the high-temperature zone is provided with an air inlet and a cable interface. The air inlet is used to connect to a high-pressure air source, and the cable interface is used to lead out the power supply / signal line of the thermal imager and the signal line of the temperature sensor.

[0007] Furthermore, the gas nozzle is a flat nozzle with the outlet facing the surface of the protective cover window.

[0008] Furthermore, the temperature sensor is of the NTC or PTC type and is installed close to the thermal imager.

[0009] Furthermore, the target temperature value preset by the PLC is set according to the reliable operating temperature range of the thermal imager.

[0010] Furthermore, the protective cover and the wiring duct can be made of titanium, stainless steel or plastic steel.

[0011] The working principle of the protection system of this invention is as follows: High-pressure air (such as compressed air or other clean gas) enters the ductwork through the air inlet. After the flow rate is regulated by the regulating valve, it flows along the duct body into the protective cover. On the one hand, the high-pressure air diffuses inside the protective cover and removes the heat generated by the thermal imager through the convection heat exchanger, maintaining its operating temperature within a stable range. On the other hand, some of the high-pressure air is directionally sprayed onto the surface of the protective cover window through the gas nozzle, removing adhering dust, oil, and other contaminants, and ensuring the infrared transmission performance of the window.

[0012] The temperature control process is as follows: The temperature sensor collects the temperature signal of the environment around the thermal imager inside the protective cover in real time, and transmits the signal to the PLC through the temperature sensor signal line; The PLC compares the real-time temperature value with the preset target temperature value (set according to the optimal operating temperature range of the thermal imager, such as 25℃~35℃), and calculates the target opening degree of the regulating valve through the PID (proportional-integral-derivative) control algorithm; The PLC sends the valve opening signal to the regulating valve, and controls the high-pressure air volume entering the protective cover by adjusting the air intake flow, ultimately achieving constant temperature control of the local area where the thermal imager is located.

[0013] The beneficial effects of this invention are as follows: 1. Precise constant temperature protection: By adjusting the high-pressure airflow in real time through PLC and PID algorithm, the working environment temperature of the thermal imager is stabilized within the target range, effectively avoiding temperature drift caused by high temperature and significantly improving the accuracy and reliability of temperature measurement.

[0014] 2. Cable safety protection: The cable routing duct simultaneously delivers high-pressure air and cables. During the flow of the high-pressure air, the cables (power supply / signal lines) are cooled synchronously to prevent long-term high temperatures from causing the cables to soften, melt, or break, thus extending the service life of the equipment.

[0015] 3. Integrated and efficient design: The gas nozzle and the protective cover window are arranged facing each other, using the same high-pressure air source to achieve both thermal imager temperature control and window purging ("one air source for two purposes"), avoiding the redundant design of independent cooling and purging systems in traditional solutions. The system has a high degree of integration and a compact structure, reducing equipment costs and maintenance complexity. Attached Figure Description

[0016] Figure 1 This is a top view of the structure of the present invention; In the diagram: 1. Protective cover; 2. Wiring duct; 3. Air inlet; 4. Human-machine interface; 5. PLC; 6. High-pressure air source; 7. Regulating valve; 8. Temperature sensor signal line; 9. Thermal imager power supply / signal line; 10. Cable interface; 11. Temperature sensor; 12. Protective cover window; 13. Gas nozzle; 14. Thermal imager. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: An infrared thermal imager constant temperature purge protection system consists of a protective cover 1, a wiring duct 2, a temperature sensor 11, a human-machine interface 4, a PLC 5, and a regulating valve 7.

[0018] The thermal imager 14 and temperature sensor 11 are installed inside the protective cover 1. The protective cover 1 provides protection for the thermal imager 14, and the temperature sensor 11 monitors the temperature inside the protective cover 1. The head end of the duct is connected to the protective cover 1, and the tail end extends out of the high-temperature zone. An air inlet 3 and a cable interface 10 are installed on the tail end. The temperature sensor signal line 8 and the thermal imager power / signal line 9 pass through the cable interface 10 and are connected to the PLC 5 and the thermal imager display system, respectively. The gas nozzle 13 is installed on the protective cover window 12, with the gas jet direction facing the protective cover window 12.

[0019] High-pressure air enters the air inlet 3 through the regulating valve 7, and then enters the protective cover 1 through the cable routing duct 2. During this process, the cable in the cable routing duct 2 and the thermal imager 14 in the protective cover 1 are cooled and protected. The high-pressure air is then sprayed out through the gas nozzle 13 to blow out the viewing window 12 of the protective cover, thus serving two purposes with one air supply.

[0020] Temperature sensor 11, with its temperature sensor signal line 8, exits the high-temperature zone through the wiring duct 2 and is connected to PLC 5. After PLC 5 measures the temperature of temperature sensor 5, it compares it with the preset temperature target value and performs PID calculation to obtain the valve opening signal, which is then sent to regulating valve 7 to achieve constant temperature in the local area where thermal imager 14 is located.

[0021] The detailed technical requirements for each structure of this invention are as follows: The protective cover 1 is made of stainless steel (high temperature and corrosion resistant). The interior is separated into a thermal imager installation chamber by a heat insulation layer (such as ceramic fiber board). The thermal imager 14 is fixed in the chamber near the viewing window 12 of the protective cover (to ensure that the imaging field of view covers the target area of ​​the furnace wall).

[0022] The wiring duct 2 is a double-layer insulated metal pipe (the inner layer is a smooth stainless steel pipe to reduce air resistance, and the outer layer is wrapped with an asbestos insulation layer). One end is welded to the side wall of the protective cover 1 and connected to the internal cavity of the protective cover, and the other end extends to the ambient temperature zone outside the blast furnace (the ambient temperature is about 25°C).

[0023] Temperature sensor 11 is a platinum resistance thermometer (accuracy ±0.1℃), which is installed inside the protective cover 1 near the thermal imager 14 (to monitor the actual temperature around the thermal imager).

[0024] The human-machine interface 4 is a touch screen control panel (installed in the external operating room of the blast furnace), which can display information such as the current temperature inside the protective cover 1, the target temperature setting value, and the percentage of the regulating valve opening, and supports manual modification of the target temperature. PLC5 uses a Siemens S7-1200 series (with built-in PID control module), and is electrically connected to the human-machine interface 4, temperature sensor signal line 8 and regulating valve 7 via shielded cable.

[0025] The regulating valve 7 is an electric proportional regulating valve (control accuracy ±1%), which is installed on the outside of the air inlet end of the wiring duct 2. The air inlet 3 is connected to the factory compressed air pipeline (supply pressure 0.4MPa~0.6MPa).

[0026] The gas nozzle 13 is a flat nozzle made of stainless steel or titanium (the width of the air outlet matches the height of the protective cover window 12), and is fixed to the inner wall of the protective cover above the protective cover window 12 by threads. The air jet direction is at a certain angle to the surface of the window to ensure that the airflow covers the entire window area. The thermal imager power supply / signal line 9 and the temperature sensor signal line 8 both pass through the inside of the cable duct 2 and are finally led out to the outside of the blast furnace through the cable interface 10, and are respectively connected to the thermal imager display system 6 (for displaying temperature images) and PLC 5.

[0027] Workflow: 1. After the system is started, compressed air enters the wiring duct 2 through the air inlet 3, and the initial flow rate is first regulated by the regulating valve 7; 2. High-pressure air flows along the wiring duct 2 into the interior of the protective cover 1, diffuses in the chamber and exchanges heat with the surface of the thermal imager 14 through convection to reduce the temperature of the thermal imager, and is sprayed onto the surface of the protective cover window 12 through the gas nozzle 13 (to remove dust and oil). 3. Temperature sensor 11 collects the temperature signal inside the protective cover in real time and transmits it to PLC5 through temperature sensor signal line 8; PLC5 compares the real-time temperature with the preset target temperature, and outputs adjustment instructions after PID calculation; 4. The regulating valve 7 adjusts its opening according to the command to reduce the high-pressure air flow, so that the temperature inside the protective cover gradually approaches the target value; when the temperature stabilizes at the target value, the system maintains the current valve opening to achieve constant temperature control. 5. The human-machine interface 4 displays information such as the current temperature and valve opening in real time. Operators can modify the target temperature or view the system status through the interface.

[0028] This embodiment achieves precise temperature control of the thermal imager, cable safety protection, and automatic window cleaning in a high-temperature metallurgical environment through integrated design, significantly improving the reliability of the infrared monitoring system.

Claims

1. A constant-temperature purge protection system for an infrared thermal imager, characterized in that, include: The protective cover (1) is equipped with a thermal imager (14) and a temperature sensor (11) inside. The front end of the protective cover (1) is provided with a viewing window for infrared radiation transmission. The cable routing duct (2) is connected to the protective cover (1) at the head end and extends to the outside of the high temperature zone at the tail end; the cables of the thermal imager (14) and the temperature sensor (11) pass through the cable routing duct (2) and out to the outside of the protective cover (1); the tail end of the cable routing duct (2) is also provided with an air inlet (3), and high pressure air enters the protective cover (1) through the air inlet (3) and the cable routing duct (2), and the high pressure air cools the thermal imager (14); The human-machine interface (4) and PLC (5) are located outside the high-temperature zone. The PLC (5) is connected to the temperature sensor (11), the human-machine interface (4) and the regulating valve (7) respectively. The regulating valve (7) is installed outside the air inlet of the wiring duct (2) and is used to regulate the air intake. The gas nozzle (13) is fixed above the protective cover window (12) with the jet direction facing the window. The air inside the protective cover (1) is discharged through the gas nozzle (13). After being regulated by the regulating valve (7), the high-pressure air enters the wiring duct (2) through the air inlet (3), flows through the protective cover (1) to cool the thermal imager (14), and blows through the protective cover window (12) through the gas nozzle (13); the signal of the temperature sensor (11) is processed by the PLC (5), and the opening of the regulating valve (7) is controlled by PID calculation to achieve local temperature stability inside the protective cover (1).

2. The constant temperature purge protection system for infrared thermal imagers according to claim 1, characterized in that, The end of the duct (2) extending to the outside of the high-temperature zone is provided with an air inlet (3) and a cable interface (10). The air inlet (3) is used to connect to the high-pressure air source (6), and the cable interface (10) is used to lead out the power supply / signal line (9) of the thermal imager and the signal line (8) of the temperature sensor.

3. The constant temperature purge protection system for infrared thermal imagers according to claim 1, characterized in that, The gas nozzle (13) is a flat nozzle with the outlet facing the surface of the protective cover window (12).

4. The constant temperature purge protection system for infrared thermal imagers according to claim 1, characterized in that, The temperature sensor (11) is of NTC or PTC type and is installed close to the thermal imager (14).

5. The constant temperature purge protection system for infrared thermal imagers according to claim 1, characterized in that, The target temperature value preset by the PLC (5) is set according to the reliable operating temperature range of the thermal imager (14).

6. The constant temperature purge protection system for infrared thermal imagers according to claim 1, characterized in that, The protective cover (1) and the wiring duct (2) can be made of titanium, stainless steel or plastic steel.

Images