Automatic control method for waste gas heat recovery device

Abstract

The invention discloses an automatic control method for a waste gas heat recovery device, which is characterized in that a control system is provided with a PLC (Programmable Logic Controller), and an acquisition unit, an execution unit and a server which are respectively in communication connection with the PLC; the control method comprises the following steps: starting up, initializing data, and monitoring and recording the operation of each device; the acquisition unit acquires related data on each device in real time and sends the data to the PLC; the PLC analyzes and processes the related data sent by the acquisition unit, judges whether the related equipment has potential safety hazards or not, and sends a corresponding prevention or first-aid instruction and an alarm instruction of a corresponding grade under the condition that the potential safety hazards exist; and the execution unit starts the prevention or emergency function of the corresponding equipment according to the instruction sent by the PLC. The automation degree of the waste gas heat recovery device is improved, and the safety performance of the waste gas heat recovery device is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of heat recovery of a setting machine, and in particular relates to an automatic control method for an exhaust gas heat recovery device. Background Art

[0002] The setting machine is an important equipment for drying, finishing and setting fabrics. Generally, the air in the setting machine is heated by heat-conducting oil, the fabric is heated and kept at a certain temperature for a certain period of time, so that the fabric structure changes and the setting purpose is achieved. However, the setting machine also discharges a large amount of hot and humid waste gas while setting and other work. Since the exhaust gas contains a large amount of hair or fabric debris, oil and gas, etc., and the temperature can reach 150-220℃, direct discharge will not only cause a huge waste of heat energy, but also cause serious pollution to the environment. Therefore, it is particularly necessary to filter and heat-recover the exhaust gas. However, the existing heat recovery equipment for setting machines cannot realize the self-cleaning function, and the internal cleaning and maintenance are difficult; at the same time, since the high-temperature exhaust gas generated by the setting machine is mixed with a large amount of fiber and oil, it is also easy to cause the deposition of impurities inside the heat recovery equipment. If it is not cleaned regularly, it will not only affect the heat recovery effect, but also cause abnormal internal temperature, which is easy to cause fire in serious cases. Summary of the invention

[0003] In view of the defects of the existing heat recovery equipment mentioned in the above background technology, the present invention provides an automatic control system for an exhaust gas heat recovery device to improve the automation level and safety performance of the device.

[0004] In order to achieve the above technical effects, the technical solution adopted by the present invention is: An automatic control method for an exhaust gas heat recovery device, characterized in that the control system is provided with a PLC and a collection unit, an execution unit and a server respectively connected to the PLC in communication; the collection unit is used to collect relevant data of each device and send it to the PLC; the PLC is used to analyze and process data and send instructions; the execution unit is used to execute relevant functions of each device according to the instructions of the PLC; the server is used to receive and store the instruction data of the PLC and various types of data collected by the collection unit. The control method includes: S1. Turn on the machine, initialize data, monitor and record the operation of each device; S2. The collection unit collects relevant data on each device in real time and sends it to the PLC; wherein the relevant data includes the waste air temperature data of the waste air inlet and waste air outlet of the heat exchanger, the fresh air temperature data of the fresh air outlet of the heat exchanger, and the wind pressure data of the waste air filter; S3. PLC analyzes and processes the relevant data sent by the acquisition unit, and determines whether there are safety hazards in the relevant equipment. If there are safety hazards, it sends corresponding prevention or emergency instructions and corresponding level of alarm instructions according to the existing safety hazards; the safety hazards include heat exchanger fire hazards, heat exchanger, fresh air filter and waste air filter blockage hazards; S4. The execution unit activates the fire protection function of the heat exchanger, the cleaning function of the heat exchanger, the fresh air filter and / or the waste air filter according to the instruction sent by the PLC.

[0005] Furthermore, in step S3, the priority principles for determining whether there are safety hazards in related equipment and taking corresponding measures for the safety hazards are, in order, the fire hazard of the heat exchanger, the blockage hazard of the heat exchanger, the blockage hazard of the exhaust air filter, and finally the blockage hazard of the fresh air filter.

[0006] Furthermore, when one of the waste air inlet temperature probe or the waste air outlet temperature probe of the heat exchanger detects that the waste air temperature exceeds 300°C, the PLC determines that there is a fire hazard in the heat exchanger, and the execution unit closes the inlet and outlet fire dampers, fresh air inlet solenoid valve, waste air inverter and fresh air inverter at both ends of the heat exchanger according to the PLC instructions, and at the same time executes the heat exchanger cleaning function, opens the heat exchanger cleaning solenoid water valve, heat exchanger cleaning solenoid gas valve, and hot water pump motor, and then shuts down the entire unit.

[0007] Furthermore, when the temperature difference detected by the exhaust air inlet temperature probe and the fresh air outlet temperature probe of the heat exchanger is greater than the set threshold range, the PLC determines that there is a risk of blockage in the heat exchanger, and the execution unit first closes the fresh air inlet valve according to the PLC instruction, and then starts the heat exchanger cleaning solenoid gas valve, heat exchanger cleaning solenoid water valve, hot water pump motor and alarm light. After cleaning for a certain time (the time set in the program); first close the heat exchanger cleaning water valve and hot water pump motor, and finally close the heat exchanger cleaning gas valve and alarm light.

[0008] Furthermore, when the wind pressure detection probe of the exhaust air filter detects that the wind pressure is lower than the set threshold range, the PLC determines that there is a risk of blockage in the exhaust air filter, and the execution unit synchronously starts the filter cleaning solenoid valve, filter drive motor, cleaning hot water pump and alarm light according to the PLC instruction.

[0009] Furthermore, in step S3, when the PLC analyzes and processes the relevant data sent by the acquisition unit and determines that there are no relevant safety hazards in each device, the PLC also analyzes and processes the extracted operating time data of each device and determines whether each device needs to perform a cleaning function.

[0010] Furthermore, the relevant data in step S2 also includes water level height data in the water tank detected by a water level controller in the water tank, and water temperature data detected by a temperature probe in the water tank.

[0011] Furthermore, in step S3, the PLC analyzes and processes the water level data and the water temperature data in the water tank, and determines whether to start the water tank water inlet function and the heating function.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The present invention connects the collection unit, the execution unit and the server through the PLC through the control system, analyzes and processes the relevant data collected by the collection unit, and sends instructions to the execution unit when it is determined that there are safety hazards in related equipment. The execution unit executes and adopts corresponding measures, thereby improving the automation level of the exhaust gas heat recovery device and ensuring the safety performance of the exhaust gas heat recovery device.

[0013] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a flow chart of the control method of the present invention; Figure 2 This is a structural diagram of the control system of the present invention. DETAILED DESCRIPTION

[0015] An automatic control method for an exhaust gas heat recovery device, such as Figure 1-2As shown, it includes an exhaust gas heat recovery device and a control system. Among them, the exhaust gas heat recovery device is equipped with a heat exchanger, an exhaust air filter, a fresh air filter, a water tank, a fresh air exhaust fan, an exhaust air exhaust fan and other equipment. Among them, the fresh air filter and the exhaust air exhaust fan are respectively connected to the fresh air inlet and the exhaust air outlet on one side of the heat exchanger through the Tianfangdiyuan transfer interface, and the exhaust air filter and the fresh air exhaust fan are respectively connected to the exhaust air inlet and the fresh air outlet on the other side of the heat exchanger through the Tianfangdiyuan transfer interface. The water tank is connected to the cleaning pipe of the spray cleaning mechanism of the heat exchanger, the cleaning pipe of the spray cleaning mechanism of the exhaust air filter, and the cleaning pipe of the spray cleaning mechanism of the fresh air filter through the water supply pipe, and is used to supply water for spray cleaning of the heat exchanger, the exhaust air filter and the fresh air filter. The cleaning pipes of the heat exchanger and the exhaust air filter adopt a double-layer pipe structure, including an inner pipe for air supply and an outer sleeve arranged outside the inner pipe for water supply. The outer sleeve is connected to the water supply pipe through the cleaning hot water pump, and the inner pipe is connected to the external air supply unit. The two ends of the inner pipe are fixedly connected to the outer pipe. The inner pipe is provided with a rod spray hole along its axial direction, and a nozzle is installed at the spray hole. The outer sleeve is provided with a through hole with an aperture larger than the outer diameter of the nozzle at the nozzle, and the nozzle passes through the through hole. The control system is provided with a PLC and a collection unit, an execution unit, an alarm unit and a server respectively connected to the PLC for communication. The collection unit is used to collect relevant data of each device and send it to the PLC; the PLC is used to analyze and process data and send instructions; the execution unit is used to execute relevant functions of each device according to the instructions of the PLC; the server is used to receive and store the instruction data of the PLC and various types of data collected by the centralized collection unit. Among them, the collection unit includes temperature probes respectively arranged at the fresh air inlet, fresh air outlet, waste air inlet and waste air outlet of the heat exchanger, a wind pressure detection probe arranged in the waste air filter, a water tank water level controller and a water tank temperature probe for water temperature detection arranged in the water tank. The execution unit includes inlet and outlet fire dampers arranged at both ends of the heat exchanger, a fresh air inlet solenoid valve, an electromagnetic water valve on the outer pipe and an electromagnetic air valve on the inner pipe of the spray cleaning mechanism cleaning pipe of the heat exchanger and the waste air filter, an electromagnetic air valve on the cleaning pipe of the spray cleaning mechanism of the fresh air filter, a driving motor for driving the rotation of the filter cartridge of the fresh air filter and a fresh air frequency converter connected to the driving motor, a driving motor for driving the rotation of the filter cartridge of the waste air filter and a waste air frequency converter connected to the driving motor, a cleaning hot water pump, a water tank inlet valve and a heater in the water tank, etc. The control method includes: S1. Turn on the machine, initialize data, monitor and record the operation of each device.

[0016] S2. The collection unit collects relevant data from each device in real time and sends it to the PLC; the relevant data includes the exhaust air temperature data of the exhaust air inlet and exhaust air outlet of the heat exchanger, the fresh air temperature data of the fresh air outlet of the heat exchanger, the wind pressure data of the exhaust air filter, the water level height data in the water tank detected by the water level controller in the water tank, and the water temperature data detected by the temperature probe in the water tank.

[0017] S3.PLC analyzes and processes the relevant data sent by the acquisition unit, and determines whether there are safety hazards in the relevant equipment. In the case of safety hazards, the corresponding prevention or emergency instructions and the corresponding level of alarm instructions are sent according to the existing safety hazards. In the case of no relevant safety hazards, the PLC also analyzes and processes the extracted time data of each device operation, and determines whether the heat exchanger, waste air filter and fresh air filter need to perform the cleaning function. Safety hazards include heat exchanger fire hazards, heat exchanger, fresh air filter and waste air filter blockage hazards, water tank water shortage hazards and water tank low water temperature hazards. Among them, the priority principle for judging whether there are safety hazards in the relevant equipment and taking corresponding measures for the existing safety hazards is that the fire hazards of the heat exchanger, the water tank water shortage hazards and the low water temperature of the water tank are executed first, followed by the blockage hazards of the heat exchanger and the waste air filter, and finally the blockage hazards of the fresh air filter.

[0018] S4. The execution unit activates the fire protection function of the heat exchanger, the cleaning function of the heat exchanger, the fresh air filter and / or the waste air filter, and the water tank water filling and heating functions according to the instructions sent by the PLC.

[0019] The execution unit of the present invention performs the following operations according to the relevant execution instructions sent by the PLC: Heat exchanger cleaning function: This function includes temperature difference automatic control mode and time control mode, specifically, 1-1. Temperature difference automatic control mode: When the temperature difference detected by the waste air inlet temperature probe and the fresh air outlet temperature probe of the heat exchanger is greater than the set threshold range, the PLC determines that there is a risk of blockage in the heat exchanger. The execution unit first closes the fresh air inlet valve according to the PLC instruction, and then starts the heat exchanger cleaning solenoid air valve, heat exchanger cleaning solenoid water valve, hot water pump motor and alarm light. After cleaning for a certain period of time (the time set in the program, such as 3-8 minutes); first close the heat exchanger cleaning water valve and hot water pump motor, and finally close the heat exchanger cleaning air valve and alarm light.

[0020] 1-2. Time control mode: When the heat exchanger is working normally, the system sets the heat exchanger to be cleaned every few hours; when the set time is up, first close the fresh air inlet valve, start the heat exchanger cleaning solenoid gas valve, heat exchanger cleaning solenoid water valve, hot water pump motor, and alarm light, and the cleaning is completed; first close the heat exchanger cleaning water valve and hot water pump motor, then close the heat exchanger cleaning gas valve and alarm light.

[0021] Exhaust air filter cleaning function: This function includes automatic air pressure control mode and time control mode, specifically, 2-1. Automatic wind pressure control mode: When the wind pressure detection probe of the exhaust air filter detects that the wind pressure is lower than the set threshold range, the PLC determines that there is a risk of blockage in the exhaust air filter, and the execution unit starts the filter cleaning solenoid valve, filter drive motor, cleaning hot water pump and alarm light synchronously according to the PLC instruction.

[0022] 2-2. Time control mode: When the waste air filter is working normally, the system sets the waste air filter to be cleaned every few hours; when the set time is up, the filter cleaning valve, filter drive motor, cleaning hot water pump and alarm light are synchronized.

[0023] Fresh air filter cleaning function: According to the system settings, when the fresh air filter works continuously, the filter cartridge will be started for cleaning every certain period of time, and the fresh air filter cleaning solenoid valve and fresh air filter drive motor will be opened; after the cleaning is completed, the cleaning solenoid valve and fresh air filter drive motor will be stopped. Fire protection function: When the waste air inlet temperature probe or one of the waste air outlet temperature probes of the heat exchanger detects that the waste air temperature exceeds 300°C, the PLC determines that there is a fire hazard in the heat exchanger. The execution unit closes the inlet and outlet fire dampers, fresh air inlet solenoid valve, waste air inverter and fresh air inverter at both ends of the heat exchanger according to the PLC instructions, and executes the heat exchanger cleaning function at the same time, opens the heat exchanger cleaning solenoid water valve, heat exchanger cleaning solenoid gas valve, and hot water pump motor, and then shuts down the entire unit. Water tank water inlet and heating function: When the water level switch of the water tank reaches the set height, the water tank water inlet valve is closed, and when it is lower than the set height, the water inlet valve is opened. When the water tank temperature probe is lower than the set temperature, the heater is turned on, and when it is higher than the set temperature, the heater is stopped. The present invention connects the acquisition unit, the execution unit and the server through the control system through the PLC, analyzes and processes the relevant data collected by the acquisition unit, sends instructions to the execution unit when it is determined that there are safety hazards in the relevant equipment, and the execution unit executes and adopts corresponding measures, thereby improving the automation level of the exhaust gas heat recovery device and ensuring the safety performance of the exhaust gas heat recovery device. The present invention uniformly uses hot water of a certain temperature for cleaning of the heat exchanger for fire protection and cleaning of the heat exchanger and the waste air filter, which is conducive to ensuring the cleaning effect, and is also conducive to improving the overall heat exchange efficiency and saving energy.

[0024] The present invention is not limited to the above-mentioned specific implementation modes. For ordinary technicians in this field, various changes made based on the above-mentioned conception without creative work all fall within the protection scope of the present invention.

Claims

1. An automatic control method for an exhaust gas heat recovery device, characterized in that: The control system comprises a PLC and a collection unit, an execution unit and a server respectively connected to the PLC; the control method comprises: S1. Turn on the machine, initialize data, monitor and record the operation of each device; the equipment includes a heat exchanger, an exhaust air filter, a fresh air filter and a water tank; S2. The acquisition unit collects relevant data from each device in real time and sends it to the PLC; the relevant data includes the waste air temperature data of the waste air inlet and waste air outlet of the heat exchanger, the fresh air temperature data of the fresh air outlet of the heat exchanger, and the wind pressure data of the waste air filter; S3. PLC analyzes and processes the relevant data sent by the acquisition unit, and determines whether there are safety hazards in the relevant equipment. If there are safety hazards, it sends corresponding prevention or emergency instructions and corresponding level of alarm instructions according to the existing safety hazards; the safety hazards include fire hazards of heat exchangers, blockage hazards of heat exchangers, fresh air filters and waste air filters; S4. The execution unit activates the fire protection function of the heat exchanger, the cleaning function of the heat exchanger, the fresh air filter and / or the waste air filter according to the instruction sent by the PLC.

2. The automatic control method of an exhaust gas heat recovery device according to claim 1, characterized in that: In step S3, the priority principles for judging whether there are safety hazards in related equipment and taking corresponding measures for the safety hazards are: fire hazard of heat exchanger, blockage hazard of heat exchanger, blockage hazard of exhaust air filter, and finally blockage hazard of fresh air filter.

3. The automatic control method of an exhaust gas heat recovery device according to claim 1, characterized in that: When the waste air inlet temperature probe or one of the waste air outlet temperature probes of the heat exchanger detects that the waste air temperature exceeds 300°C, the PLC determines that there is a fire hazard in the heat exchanger. The execution unit closes the inlet and outlet fire dampers, fresh air inlet solenoid valve, waste air inverter and fresh air inverter at both ends of the heat exchanger according to the PLC instructions, and at the same time executes the heat exchanger cleaning function, opens the heat exchanger cleaning solenoid water valve, heat exchanger cleaning solenoid gas valve, and hot water pump motor, and then shuts down the entire unit.

4. The automatic control method of an exhaust gas heat recovery device according to claim 1, characterized in that: When the temperature difference detected by the waste air inlet temperature probe and the fresh air outlet temperature probe of the heat exchanger is greater than the set threshold range, the PLC determines that there is a risk of blockage in the heat exchanger. The execution unit first closes the fresh air inlet valve according to the PLC instruction, and then starts the heat exchanger cleaning solenoid gas valve, heat exchanger cleaning solenoid water valve, hot water pump motor and alarm light. After cleaning for a certain time (the time set in the program), first close the heat exchanger cleaning water valve and hot water pump motor, and finally close the heat exchanger cleaning gas valve and alarm light.

5. The automatic control method of an exhaust gas heat recovery device according to claim 1, characterized in that: When the wind pressure detection probe of the exhaust air filter detects that the wind pressure is lower than the set threshold range, the PLC determines that there is a risk of blockage in the exhaust air filter, and the execution unit synchronously starts the filter cleaning solenoid valve, filter drive motor, cleaning hot water pump and alarm light according to the PLC instruction.

6. The automatic control method of an exhaust gas heat recovery device according to claim 1, characterized in that: In step S3, when the PLC analyzes and processes the relevant data sent by the acquisition unit and determines that there are no relevant safety hazards in each device, the PLC also analyzes and processes the extracted operating time data of each device and determines whether the cleaning time of each device exceeds the set time compared with the last cleaning time. If it exceeds the set time, the PLC sends a cleaning instruction to the execution unit, and the execution unit activates the cleaning function of the corresponding device.

7. The automatic control method of an exhaust gas heat recovery device according to claim 1, characterized in that: The relevant data in step S2 also include water level data in the water tank detected by a water level controller in the water tank, and water temperature data detected by a temperature probe in the water tank.

8. The automatic control method of an exhaust gas heat recovery device according to claim 7, characterized in that: In step S3, the PLC analyzes and processes the water level data and the water temperature data in the water tank, and determines whether to start the water tank water inlet function and the heating function.

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