Air induction control method, device and system for thermoforming machine group

Abstract

The application relates to the environmental protection field and provides an air induction control method, device and system of a thermoforming unit, the thermoforming unit comprising a plurality of thermoforming machines, each thermoforming machine being provided with a fume hood and an operating parameter sensor in correspondence, the fume hood being communicated with an exhaust duct, and the operating parameter sensor being used for monitoring the operating parameter of the thermoforming machine; the air induction control method comprises the following steps: obtaining the operating parameter monitored by each operating parameter sensor; determining the current operating state of the thermoforming machine according to the operating parameter, wherein the current operating state is used for representing the emission amount of volatile organic compounds during thermoforming; and adjusting the air valve opening degree of the exhaust duct and the output power of an air induction fan according to the current operating state, wherein the air induction fan is communicated with the exhaust duct and is used for providing negative pressure to the exhaust duct. The generated VOC gas can be completely removed, and the power consumption of the air induction fan can be effectively reduced, so that the energy consumption can be effectively saved.

Description

Technical Field

[0001] This application relates to the field of environmental protection technology, and in particular to a method for controlling the induced draft of a thermoforming unit. Background Technology

[0002] Thermoforming is a plastic processing method that transforms thermoplastics into various products. For example, in the manufacture of refrigerator liners, vacuum forming is commonly used. During thermoforming, the heated plastic sheets may produce volatile organic compounds (VOCs), which can easily pollute the environment.

[0003] In related technologies, a gas collection hood is installed on each thermoforming machine in the thermoforming unit. The gas collection hood is connected to the environmental protection exhaust duct. The air ducts corresponding to each thermoforming machine are collected and enter the activated carbon box for adsorption treatment through the main pipe. In order to save energy, the power of the exhaust fan is usually controlled according to the number of thermoforming machines that are turned on.

[0004] However, in related technologies, reducing the power of the induced draft fan when some thermoforming machines are not turned on may result in insufficient suction for other operating thermoforming machines, which may lead to the inability of VOC gases to be discharged in a timely manner, easily causing environmental pollution. Summary of the Invention

[0005] This application aims to at least solve one of the technical problems existing in the related art. To this end, this application proposes an induced draft control method for a thermoforming unit, which can synchronously adjust the opening of the air valve and the output power of the induced draft fan according to the operating status of the thermoforming machine, so as to keep the suction force of the induced draft fan on the operating thermoforming machine constant, ensuring that the generated VOC gas is completely removed, and at the same time, effectively reducing the power consumption of the induced draft fan, thus effectively saving energy.

[0006] This application also proposes an induced draft control device for a thermoforming unit.

[0007] This application also proposes an induced draft control system for a thermoforming unit.

[0008] According to an embodiment of the first aspect of this application, a method for controlling the induced draft of a thermoforming unit includes multiple thermoforming machines. Each thermoforming machine is equipped with a gas collection hood and an operating parameter sensor. The gas collection hood is connected to an exhaust duct, and the operating parameter sensor is used to monitor the operating parameters of the thermoforming machine. The method includes:

[0009] The operating parameters monitored by each of the aforementioned operating parameter sensors are acquired;

[0010] Based on the operating parameters, the current operating state of the thermoforming machine is determined, and the current operating state is used to characterize the amount of volatile organic compounds released during thermoforming.

[0011] Based on the current operating status, the opening degree of the air valve in the exhaust duct and the output power of the induced draft fan are adjusted. The induced draft fan is connected to the exhaust duct and is used to provide negative pressure to the exhaust duct.

[0012] According to the induced draft control method of the thermoforming unit in this application embodiment, by setting an operating parameter sensor on each thermoforming machine, the operating parameter sensor collects the operating parameters of each thermoforming machine, thereby conveniently and quickly determining the operating status of each thermoforming machine (e.g., full-power production, half-power production, standby, or shutdown). Based on different operating states, the opening of the air valve in the corresponding exhaust duct of each thermoforming machine is adjusted, and the operating power of the induced draft fan is also adjusted. For example, when a thermoforming machine is in a shutdown state, the corresponding air valve can be closed. At this time, with the induced draft fan operating power remaining unchanged, the suction force provided by the induced draft fan to other operating thermoforming machines increases, indicating an excess of induced draft fan operating power. In this application embodiment, by adjusting the output power of the induced draft fan according to the current operating state of the thermoforming machine, the output power of the induced draft fan can be reduced accordingly, effectively reducing the energy loss of the induced draft fan. In addition, this embodiment adjusts the opening of the air valve and the output power of the induced draft fan according to the current operating status of the thermoforming machine. In this way, compared with related technologies, it can also reduce the air leakage of the exhaust pipe corresponding to the thermoforming machine in the shutdown or standby state, that is, it can effectively ensure the suction force of the thermoforming machine in the production state, effectively ensure that the VOC gas is completely removed, and avoid environmental pollution.

[0013] According to one embodiment of this application, the step of determining the current operating state of the thermoforming machine based on the operating parameters includes:

[0014] Based on the operating parameters, determine the operating power of the heating tile of the thermoforming machine;

[0015] The current operating status of the thermoforming machine is determined based on the operating power.

[0016] In this embodiment, the operating power of the heating tile is determined by the operating parameters of the thermoforming machine. This allows for accurate determination of the current operating status of the thermoforming machine, enabling precise adjustment of the air valve opening and the output power of the induced draft fan. On the one hand, this reduces unnecessary energy waste, and on the other hand, it ensures the suction force of the thermoforming machine in production, guaranteeing that the generated VOC gas is completely removed, effectively preventing environmental pollution.

[0017] According to one embodiment of this application, an airflow state monitoring sensor is provided at the connection between the gas collection hood and the outlet of the thermoforming machine, the airflow state monitoring sensor being used to monitor the airflow state at the outlet of the thermoforming machine; after the step of determining the current operating state of the thermoforming machine based on the operating power, the method further includes:

[0018] Obtain the airflow state parameters monitored by the airflow state monitoring sensor;

[0019] Based on the airflow state parameters, determine the amount of heat loss generated by the thermoforming machine as it flows with the airflow;

[0020] The step of adjusting the opening degree of the exhaust duct damper and the output power of the induced draft fan according to the current operating state includes:

[0021] Based on the current operating status and the amount of heat loss, adjust the opening of the exhaust duct valve and the output power of the induced draft fan.

[0022] In this embodiment, an airflow state monitoring sensor is used to monitor airflow state parameters. This allows for the determination of heat loss to the thermoforming machine caused by the induced draft fan during operation. When adjusting the air valve opening and the output power of the induced draft fan, the air valve opening and the output power of the induced draft fan can also be adjusted according to the current operating status and heat loss of the thermoforming machine. This ensures that the adjusted output power of the induced draft fan will not cause excessive heat loss to the thermoforming machine, thus effectively saving energy.

[0023] According to one embodiment of this application, the step of adjusting the opening degree of the exhaust duct damper and the output power of the induced draft fan based on the current operating state and the heat loss includes:

[0024] The exhaust heat dissipation coefficient of the thermoforming machine is determined based on the operating power and the heat loss.

[0025] Determine whether the exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range;

[0026] If the exhaust heat dissipation coefficient exceeds the preset exhaust heat dissipation coefficient range, adjust the opening of the air valve and the output power of the induced draft fan.

[0027] By comparing the exhaust heat dissipation coefficient of the thermoforming machine with the preset exhaust heat dissipation coefficient, the heat loss of the thermoforming machine can be effectively controlled within a suitable range. This ensures that all VOC gases generated during the thermoforming process are removed, while reducing heat loss and energy consumption.

[0028] According to one embodiment of this application, the step of adjusting the opening of the air valve and the output power of the induced draft fan when the exhaust heat dissipation coefficient exceeds the preset exhaust heat dissipation coefficient range includes:

[0029] When the exhaust heat dissipation coefficient is greater than or equal to a first preset threshold, the opening of the air valve and the output power of the induced draft fan are adjusted in a first adjustment cycle until the exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range, where the first preset threshold is the upper limit of the exhaust heat dissipation coefficient range; wherein, the first adjustment cycle includes:

[0030] Increase the opening of the air valve by the first opening adjustment value;

[0031] The output power of the induced draft fan is increased by a first power adjustment value, so that the exhaust volume in the main air duct increases by a first preset exhaust volume.

[0032] Determine whether the current exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range.

[0033] In this embodiment, the opening degree of the air valve and the output power of the induced draft fan are adjusted through the first adjustment cycle, which can avoid the situation where the adjustment range of the air valve opening degree and the output power of the induced draft fan is too large, effectively reducing the number of adjustments and improving the adjustment efficiency.

[0034] According to one embodiment of this application, the step of adjusting the opening of the air valve and the output power of the induced draft fan when the exhaust heat dissipation coefficient exceeds the preset exhaust heat dissipation coefficient range further includes:

[0035] When the exhaust heat dissipation coefficient is less than or equal to a second preset threshold, the opening of the air valve and the output power of the induced draft fan are adjusted in a second adjustment cycle until the exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range, where the second preset threshold is the lower limit of the exhaust heat dissipation coefficient range; wherein, the second adjustment cycle includes:

[0036] The opening of the air valve is reduced by the second opening adjustment value;

[0037] The output power of the induced draft fan is reduced by the second power adjustment value, so that the exhaust volume in the main air duct is reduced by the second preset exhaust volume.

[0038] Determine whether the current exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range.

[0039] According to one embodiment of this application, the airflow state monitoring sensor includes a thermal anemometer, and the airflow state parameters include wind speed and airflow temperature.

[0040] According to one embodiment of this application, the thermoforming machine is equipped with a current monitoring sensor, which is used to monitor the magnitude of the current flowing through the heating tile; determining the operating power of the heating tile of the thermoforming machine based on the operating parameters includes:

[0041] The operating power of the heating tile of the thermoforming machine is determined based on the magnitude of the current.

[0042] According to one embodiment of this application, the thermoforming machine has a manual / automatic switch, and the operating parameters include the on / off state of the manual / automatic switch; the step of determining the current operating state of the thermoforming machine based on the operating parameters includes:

[0043] Determine whether the current operating state is a standby state based on the switch quantity;

[0044] The step of adjusting the opening degree of the exhaust duct damper and the output power of the induced draft fan according to the current operating state includes:

[0045] When the current operating state is standby, adjust the opening of the air valve and the output power of the induced draft fan so that the exhaust volume of the exhaust duct is 10%-20% of the rated exhaust volume; wherein, the rated exhaust volume is the exhaust volume in the exhaust duct when all the thermoforming machines are in production and the induced draft fan is running at rated power.

[0046] According to one embodiment of this application, a relay fan is provided in the exhaust duct; the step of adjusting the opening degree of the exhaust duct valve and the output power of the induced draft fan according to the current operating state further includes:

[0047] Based on the current operating status, adjust the opening of the exhaust duct damper and the output power of the relay fan; or,

[0048] Based on the current operating status, adjust the opening of the exhaust duct valve, the output power of the relay fan, and the output power of the induced draft fan.

[0049] According to one embodiment of this application, each of the exhaust ducts converges and connects to a main air duct, and a micro differential pressure sensor is installed in the main air duct to monitor the static pressure parameter within the main air duct; the method further includes:

[0050] Obtain the reference negative pressure setting value within the main air duct;

[0051] The step of adjusting the opening degree of the exhaust duct damper and the output power of the induced draft fan according to the current operating state further includes:

[0052] Adjust the opening degree of the air valve according to the current operating status;

[0053] Obtain the current negative pressure value in the main air duct monitored by the micro differential pressure sensor;

[0054] The output power of the induced draft fan is adjusted according to the current negative pressure value and the reference negative pressure setting value so that the negative pressure value in the main air duct is maintained at the reference negative pressure setting value.

[0055] According to one embodiment of this application, after the step of adjusting the output power of the induced draft fan according to the current negative pressure value and the reference negative pressure setting value to maintain the negative pressure value in the main air duct at the reference negative pressure setting value, the method further includes:

[0056] Obtain the average opening value of each of the air valves within a first preset time period;

[0057] Determine whether the average opening value of all the stated openings is less than or equal to the preset opening threshold of the damper;

[0058] If any of the average opening values ​​is greater than the preset opening threshold of the air valve, the output power of the induced draft fan is adjusted in a third adjustment cycle until all the average opening values ​​are less than or equal to the preset opening threshold of the air valve; wherein, the third adjustment cycle includes:

[0059] Reduce the output power of the exhaust fan so that the negative pressure value of the main air duct decreases by a first preset pressure adjustment value;

[0060] Maintain the current negative pressure value in the main air duct for a second preset time length, and obtain the average opening value of each air valve within the second preset time length;

[0061] Determine whether the average opening value of all valves is less than or equal to the preset opening threshold of the air valve under the current negative pressure value.

[0062] According to one embodiment of this application, a wind speed monitor is installed on one edge of the gas collection hood facing the thermoforming machine, the wind speed monitor being used to monitor the wind speed at the far edge of the gas collection hood; before the step of adjusting the output power of the induced draft fan in a third adjustment cycle until the average value of all the openings is less than or equal to the preset opening threshold of the air valve, the method further includes:

[0063] Obtain the wind speed corresponding to the thermoforming machine in production status;

[0064] Determine whether all the wind speeds are less than or equal to a preset wind speed threshold.

[0065] When all the wind speeds are greater than the preset wind speed threshold, the output power of the induced draft fan is adjusted in the third adjustment cycle.

[0066] In this embodiment, by installing a wind speed monitor on the edge of the gas collection hood facing the thermoforming machine, the wind speed is determined before adjusting the output power of the induced draft fan. This ensures that the suction force of the thermoforming machine in production meets the minimum wind speed requirement, effectively ensuring the complete removal of VOC gases and effectively avoiding environmental pollution.

[0067] According to one embodiment of this application, the method further includes:

[0068] If at least one of the wind speeds is less than or equal to the preset wind speed threshold, the output power of the induced draft fan is adjusted in a fourth adjustment cycle until all the wind speeds are greater than the preset wind speed threshold; wherein, the fourth adjustment cycle includes:

[0069] Increase the output power of the induced draft fan so that the negative pressure value of the main air duct increases by the second preset pressure adjustment value;

[0070] Determine whether any of the current wind speeds is less than or equal to the preset wind speed threshold.

[0071] According to one embodiment of this application, obtaining the reference negative pressure setting value in the main air duct includes:

[0072] With all the aforementioned thermoforming machines operating at full capacity and the induced draft fan running at rated power, the negative pressure value monitored by the micro differential pressure sensor is obtained.

[0073] The negative pressure value is determined as the reference negative pressure setting value.

[0074] According to a second aspect embodiment of this application, a draft control device for a thermoforming machine unit includes multiple thermoforming machines. Each thermoforming machine is equipped with a draft hood and an operating parameter sensor. The draft hood is connected to an exhaust duct, and the operating parameter sensor is used to monitor the operating parameters of the thermoforming machine. The device includes:

[0075] The acquisition module is used to acquire the operating parameters monitored by each of the operating parameter sensors;

[0076] The determining module is used to determine the current operating state of the thermoforming machine based on the operating parameters, wherein the current operating state is used to characterize the amount of volatile organic compounds released during thermoforming;

[0077] The adjustment module is used to adjust the opening degree of the air valve of the exhaust duct and the output power of the induced draft fan according to the current operating state. The induced draft fan is connected to the exhaust duct and is used to provide negative pressure to the exhaust duct.

[0078] An induced draft control system for a thermoforming machine according to a third aspect embodiment of this application includes:

[0079] Multiple thermoforming machines, each with an operating parameter sensor; the operating parameter sensor is used to monitor the operating parameters of the thermoforming machine;

[0080] Multiple gas collection hoods are provided, and the gas collection hoods are correspondingly arranged with the thermoforming machine;

[0081] An exhaust duct, which is connected to a plurality of the gas collection hoods;

[0082] An exhaust fan is connected to the exhaust duct and is used to provide negative pressure to the exhaust duct.

[0083] A memory, wherein the memory stores computer programs;

[0084] A processor for executing the computer program to implement the induced draft control method for a thermoforming unit according to any one of the embodiments of the first aspect of this application.

[0085] The above-described one or more technical solutions in the embodiments of this application have at least one of the following technical effects:

[0086] By installing operating parameter sensors on each thermoforming machine, the operating parameters of each machine can be collected, allowing for quick and easy determination of its operating status (e.g., full-power production, half-power production, standby, or shutdown). Based on these different operating statuses, the opening of the exhaust valve in the corresponding duct of each thermoforming machine can be adjusted, along with the operating power of the induced draft fan. For example, when a thermoforming machine is shut down, its corresponding exhaust valve can be closed. In this case, while the induced draft fan's operating power remains constant, the suction force it provides to other operating thermoforming machines increases, indicating excessive induced draft fan power. In this embodiment, adjusting the induced draft fan's output power according to the current operating status of the thermoforming machine reduces its output power, effectively minimizing energy loss. In addition, this embodiment adjusts the opening of the air valve and the output power of the induced draft fan according to the current operating status of the thermoforming machine. In this way, compared with related technologies, it can also reduce the air leakage of the exhaust pipe corresponding to the thermoforming machine in the shutdown or standby state, that is, it can effectively ensure the suction force of the thermoforming machine in the production state, effectively ensure that the VOC gas is completely removed, and avoid environmental pollution.

[0087] Furthermore, by determining the operating power of the heating tile through the operating parameters of the thermoforming machine, the current operating status of the thermoforming machine can be accurately determined. This allows for precise adjustment of the air valve opening and the output power of the induced draft fan. On the one hand, this reduces unnecessary energy waste, and on the other hand, it ensures the suction force of the thermoforming machine in production, guaranteeing that the generated VOC gases are completely removed, effectively preventing environmental pollution.

[0088] Furthermore, by setting up airflow state monitoring sensors to monitor airflow state parameters, it is possible to determine the heat loss caused to the thermoforming machine when the induced draft fan is working. When adjusting the air valve opening and the output power of the induced draft fan, the air valve opening and the output power of the induced draft fan can also be adjusted according to the current operating status of the thermoforming machine and the heat loss. This ensures that the adjusted output power of the induced draft fan will not cause excessive heat loss to the thermoforming machine, and can effectively save energy consumption.

[0089] Furthermore, by comparing the exhaust heat dissipation coefficient of the thermoforming machine with the preset exhaust heat dissipation coefficient, the heat loss of the thermoforming machine can be effectively controlled within a suitable range. This ensures that all VOC gases generated during the thermoforming process are removed, while reducing heat loss and energy consumption.

[0090] Furthermore, by adjusting the opening of the air valve and the output power of the induced draft fan through the first adjustment cycle, it is possible to avoid excessive adjustment of the air valve opening and the output power of the induced draft fan, thereby effectively reducing the number of adjustments and improving adjustment efficiency.

[0091] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0092] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0093] Figure 1 This is a schematic diagram of the induced draft system of the thermoforming unit provided in the embodiments of this application;

[0094] Figure 2 This is a flowchart illustrating an implementation of the induced draft control method for a thermoforming unit provided in this application embodiment;

[0095] Figure 3 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application;

[0096] Figure 4 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application;

[0097] Figure 5 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application;

[0098] Figure 6 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application;

[0099] Figure 7 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application;

[0100] Figure 8 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application;

[0101] Figure 9 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application;

[0102] Figure 10This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application;

[0103] Figure 11 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application;

[0104] Figure 12 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application;

[0105] Figure 13 This is a flowchart illustrating one implementation of the induced draft control method for a thermoforming unit provided in this application embodiment;

[0106] Figure 14 This is a structural block diagram of the induced draft control device for the thermoforming unit provided in the embodiments of this application.

[0107] Figure label:

[0108] 10-Fuel collection hood; 20-Exhaust duct; 30-Exhaust fan; 40-Air valve; 50-Relay fan; 60-Main air duct. Detailed Implementation

[0109] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but should not be used to limit the scope of this application.

[0110] In the description of the embodiments of this application, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0111] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0112] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0113] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0114] Thermoforming is a secondary molding technology that uses thermoplastics as raw materials. Common thermoforming methods include vacuum forming (also known as thermoforming), pneumatic thermoforming, and die thermoforming. Of course, thermoforming also includes other thermoforming methods, which will not be listed in detail in this embodiment.

[0115] Typically, thermoforming requires heating thermoplastic materials. When plastic raw materials are heated, they may produce volatile organic compounds, which can easily cause environmental pollution.

[0116] To avoid environmental pollution, a gas collection hood is usually installed on the top of each thermoforming machine in the thermoforming workshop. The gas collection hood is connected to the main air duct. After the air from each main air duct converges, it enters the activated carbon box for adsorption treatment, thereby treating the VOC gas generated during the thermoforming process and reducing environmental pollution.

[0117] Specifically, the gas flow in the exhaust duct is provided by one or more centrifugal fans, and the VOC gas emission is controlled by the fan control system to change the exhaust volume of the system by starting, stopping and changing the frequency of the fans.

[0118] It is understandable that when the fan is turned on, it creates negative pressure in all the exhaust ducts, thereby providing suction to the gas collection hood connected to the thermoforming machine and removing the VOC gas generated during the thermoforming process.

[0119] In some examples of related technologies, when a portion of the thermoforming machine is not turned on (e.g., when the thermoforming machine is under maintenance or mold replacement), the total air extraction volume of the fan is changed by adjusting the frequency of the frequency converter. At this time, the air volume in the exhaust duct changes according to the duct resistance characteristics.

[0120] It is also understandable that the thermoforming machine stops completely when the fan stops, thus avoiding VOC gas pollution to the environment.

[0121] Typically, VOC exhaust ducts are designed based on the rated power of the thermoforming unit. To prevent VOC leakage and environmental pollution, the size of the exhaust duct and the output power of the fan are usually determined by the required exhaust volume for continuous thermoforming mold operation.

[0122] When a thermoforming machine is not operating at its rated full power, the air valves in the exhaust duct may not close accurately, resulting in redundant exhaust from the fan for that portion of the thermoforming machine. In other words, some of the fan's output power is wasted, increasing energy consumption. Furthermore, reducing the fan's output power by changing the frequency will decrease the exhaust volume of some thermoforming machines operating at their rated power, potentially leading to the inability to timely extract and discharge VOC gases, posing a risk of environmental pollution.

[0123] Figure 1 This is a schematic diagram of the induced draft system of the thermoforming unit provided in the embodiments of this application. Figure 2 This is a flowchart illustrating one implementation of the induced draft control method for a thermoforming unit provided in this application embodiment.

[0124] In response to the technical problems existing in the relevant technologies, refer to Figure 1 and Figure 2 As shown in the figure, this application provides a method for controlling the induced draft of a thermoforming machine, which can be specifically applied to the induced draft system of a thermoforming machine. The thermoforming machine (not shown in the figure) can be a vacuum forming machine, a blow molding machine, an injection molding machine, etc. It is understood that the thermoforming machine can also be other thermoforming equipment that requires heating for forming. The specific types of thermoforming machines in this application are only illustrative examples and are not intended to limit the specific types of thermoforming machines.

[0125] It is understood that the thermoforming unit includes multiple thermoforming machines (not shown in the figure). In the embodiments of this application, each thermoforming machine is equipped with an operating parameter sensor (not shown in the figure).

[0126] Specifically, in this embodiment, the operating parameter sensor can monitor the operating parameters of the thermoforming machine. These operating parameters directly reflect the operating status of the thermoforming machine, thereby reflecting the amount of VOC gas emitted. Therefore, referring to... Figure 2 As shown in the embodiment of this application, the induced draft control method for a thermoforming unit specifically includes the following steps:

[0127] Step 201: Obtain the operating parameters monitored by the sensors for each operating parameter.

[0128] As a specific example of an embodiment of this application, the operating parameter can specifically be the temperature of the heating tile of the thermoforming machine, or, in some examples, the operating parameter can be the temperature of the working surface (heating surface) of the thermoforming machine. It is understood that the amount of VOC gas released is usually directly related to the heating temperature; that is, the higher the heating temperature, the greater the amount of VOC gas released, and the lower the heating temperature, the smaller the amount of VOC gas released.

[0129] It is understood that in this embodiment, the thermoforming unit includes multiple thermoforming machines, and each thermoforming machine is equipped with an operating parameter sensor. Therefore, in this embodiment, multiple operating parameters are obtained. It is understood that the operating parameter sensor can be electrically connected to a device with data processing capabilities, such as a controller or processor, and the operating parameter sensor transmits the monitored operating parameters to the processor for processing. In some specific examples, the processor can be a Central Processing Unit (CPU), a Microcontroller Unit (MCU), or a Field Programmable Gate Array (FPGA). As a specific example of this embodiment, the processor can also be a Programmable Logic Controller (PLC). In other specific examples of this embodiment, the processor can also be a Proportional Integral Derivative (PID) controller.

[0130] Step 202: Determine the current operating status of the thermoforming machine based on the operating parameters; wherein, the current operating status is used to characterize the amount of volatile organic compounds released during thermoforming.

[0131] In other words, in this embodiment of the application, the processor determines the working state of the corresponding thermoforming machine based on each operating parameter. Specifically, the working state of the thermoforming machine can be: production state (full power production, half power production), standby state (which may also be called maintenance state or mold changing state in some examples), or shutdown state, etc.

[0132] In specific configurations, in this embodiment of the application, a temperature sensor (e.g., a thermistor) can be installed on the heating surface of the thermoforming machine to monitor the temperature of the heating surface, thereby obtaining the operating parameters of the thermoforming machine.

[0133] It is understandable that the required heating temperature varies depending on the size of the model, and the amount of VOC gas released also varies. For example, a larger model requires a higher temperature to heat the thermoplastic material, while a relatively smaller model requires a relatively lower heating temperature. In this embodiment, by monitoring the heating temperature of the heating surface of the thermoforming machine, the size of the model being formed can also be reflected, thereby reflecting the amount of VOC gas released.

[0134] Step 203: Adjust the opening degree of the exhaust duct damper 40 and the output power of the induced draft fan 30 according to the current operating status.

[0135] Specifically, refer to Figure 1 As shown, the induced draft fan 30 is connected to the exhaust duct, and the induced draft fan 30 is used to provide negative pressure to the exhaust duct.

[0136] In specific settings, the exhaust pipe valve 40 can be a manual valve 40. That is, after the processor determines the operating status of the corresponding thermoforming machine based on each operating parameter, the operator adjusts the opening of the manual valve 40 according to the corresponding operating status.

[0137] It is understood that, in order to improve the accuracy of the operator's adjustment of the opening of the manual air valve 40, that is, to ensure that the adjusted opening of the air valve 40 corresponds to the operating status of the thermoforming machine, a display device can be provided in this embodiment. The display device is connected to the processor. After the processor determines the corresponding operating status of the thermoforming machine based on each operating parameter, it can send the operating status of the thermoforming machine to the display device for display, thereby facilitating the operator to adjust the opening of the air valve 40.

[0138] It should be noted that the display device can be configured to correspond to the thermoforming machine (e.g., a fixed display device mounted on the corresponding thermoforming machine). This allows the operator to visually see the current operating status of the thermoforming machine and adjust the opening of the corresponding air valve 40 accordingly. In some optional examples of this application's embodiments, the display device can also be a mobile device such as a smart terminal, tablet computer, or laptop computer. Specifically, the operator can check the current operating status of the corresponding thermoforming machine according to the inspection progress and adjust the opening of the corresponding air valve 40 accordingly.

[0139] It is understood that, in this embodiment of the application, after the processor determines the corresponding operating state of the thermoforming machine based on each operating parameter, it can also send the opening requirement of the air valve 40 corresponding to the current operating state of the thermoforming machine to the display device for display. For example, when the thermoforming machine is in a stopped state, the opening requirement of the air valve 40 is 0; when the thermoforming machine is in a full-power production state, the opening requirement of the air valve 40 is 100%, etc. This facilitates the operator to adjust the air valve 40 according to the corresponding opening, improving the accuracy of the air valve 40 opening adjustment.

[0140] In some alternative examples of embodiments of this application, the air valve 40 may also be an automatic air valve 40. For example, in some examples, the air valve 40 may be either an electric air valve 40 or a pneumatic air valve 40. After determining the operating state of each thermoforming machine, the processor can send a control signal to the air valve 40 according to the operating state of each thermoforming machine, thereby adjusting the opening degree of the air valve 40.

[0141] In some alternative examples of the embodiments of this application, the manual air valve 40 can be automated. For example, a drive component (such as a servo motor, stepper motor, or synchronous motor) can be added to the exhaust duct, and the drive component is connected to the adjustment handle of the air valve 40. After determining the operating status of each thermoforming machine, the processor can send a corresponding control signal to the drive component according to the operating status of each thermoforming machine, thereby controlling the drive component to adjust the opening of the air valve 40.

[0142] In this embodiment, by setting an operating parameter sensor in each thermoforming machine, the operating parameters of each thermoforming machine are monitored. After the processor determines the operating status of each thermoforming machine based on each operating parameter, it can promptly control the corresponding air valve 40 of the thermoforming machine for adjustment. For example, for a thermoforming machine that is in a shutdown state, the air valve 40 can be shut off in time to avoid wasting exhaust volume.

[0143] It is also understandable that the output power of the induced draft fan 30 is usually determined by the exhaust volume required for operation under the maximum mold operation conditions of continuous thermoforming. Therefore, after adjusting the opening of the air valve 40 according to the operating status of the thermoforming machine, when the induced draft fan 30 is running at its rated output power, the negative pressure provided by the induced draft fan 30 to the exhaust duct 20 is greater than the actual air volume requirement, and at this time the output power of the induced draft fan 30 is too high; therefore, in this embodiment of the application, the output power of the induced draft fan 30 can also be adjusted (for example, by reducing the output power of the induced draft fan 30).

[0144] Specifically, in this embodiment, the induced draft fan 30 may be equipped with a frequency converter, and the processor may send control commands to the frequency converter to adjust the operating frequency of the induced draft fan 30, thereby adjusting the output power of the induced draft fan 30.

[0145] It should be noted that in some possible examples, the processor may increase the opening of the air valve 40 according to the current operating status of the thermoforming machine. In this case, the output power of the induced draft fan 30 may also be increased.

[0146] In addition, in this embodiment, the opening of the air valve 40 may be adjusted first, and then the output power of the induced draft fan 30 may be adjusted; in some possible examples, the output power of the induced draft fan 30 may be adjusted first, and then the valve opening may be adjusted. In this embodiment, the order of adjusting the valve opening and adjusting the output power of the induced draft fan 30 is not limited.

[0147] As a specific example of an embodiment of this application, when the processor determines the working state of the thermoforming machine and needs to reduce the opening of the air valve 40 and decrease the output power of the induced draft fan 30, the opening of the air valve 40 can be adjusted first, and then the output power of the induced draft fan 30 can be adjusted. This avoids leakage of the negative pressure provided by the induced draft fan 30 from the air valve 40, which requires adjustment of its opening. In other words, it ensures that the negative pressure provided by the induced draft fan 30 can always completely extract the VOC gases generated during thermoforming by other thermoforming machines, effectively preventing environmental pollution.

[0148] In another specific example of the embodiments of this application, when the processor determines the working state of the thermoforming machine and needs to increase the opening of the air valve 40 and the output power of the induced draft fan 30, the output power of the induced draft fan 30 can be adjusted first, and then the opening of the air valve 40 can be adjusted.

[0149] According to the induced draft control method of the thermoforming unit in this application embodiment, by setting an operating parameter sensor on each thermoforming machine, the operating parameter sensor collects the operating parameters of each thermoforming machine, thereby conveniently and quickly determining the operating status of each thermoforming machine (e.g., full-power production, half-power production, standby, or shutdown). Based on different operating statuses, the opening of the air valve 40 of the corresponding exhaust duct of each thermoforming machine is adjusted, and the operating power of the induced draft fan 30 is adjusted simultaneously. For example, when a thermoforming machine is in a shutdown state, the corresponding air valve 40 can be closed. At this time, with the operating power of the induced draft fan 30 remaining unchanged, the suction force provided by the induced draft fan 30 to other operating thermoforming machines increases, indicating an excess operating power of the induced draft fan 30. In this application embodiment, by adjusting the output power of the induced draft fan 30 according to the current operating status of the thermoforming machine, the output power of the induced draft fan 30 can be reduced accordingly, effectively reducing the energy loss of the induced draft fan 30. In addition, according to the current operating status of the thermoforming machine, the opening degree of the air valve 40 and the output power of the induced draft fan 30 are adjusted. In this way, compared with related technologies, the leakage of the exhaust pipe corresponding to the thermoforming machine in the shutdown or standby state can be reduced. That is, the suction force of the thermoforming machine in the production state can be effectively guaranteed, and the VOC gas can be completely removed, avoiding pollution to the environment.

[0150] Figure 3 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application.

[0151] In some optional examples of the embodiments of this application, reference is made to Figure 3 As shown, the induced draft control method for the thermoforming unit specifically includes the following steps:

[0152] Step 301: Obtain the operating parameters monitored by the sensors for each operating parameter.

[0153] It is understood that in the embodiments of this application, the methods for obtaining the operating parameters of each thermoforming machine may be the same as or similar to those described in the foregoing embodiments of this application. For details, please refer to the detailed description of the foregoing embodiments of this application.

[0154] Step 302: Determine the operating power of the heating tile of the thermoforming machine based on the operating parameters.

[0155] Understandably, thermoforming machines typically use heating elements to heat thermoplastics (such as plastic sheets and films). Therefore, the operating power of the heating elements directly reflects the amount of VOCs released when the thermoplastic is heated. For example, the higher the operating power of the heating elements, the higher the heating temperature of the thermoplastic, and the greater the amount of VOCs released; conversely, the lower the operating power of the heating elements, the lower the heating temperature of the thermoplastic, and the smaller the amount of VOCs released.

[0156] As a specific example of an embodiment of this application, the operating parameter can be the magnitude of the current flowing through the heating tile. Specifically, the operating parameter sensor can be a current monitoring sensor installed on the thermoforming machine. The current monitoring sensor can specifically be a current transformer. That is, in this embodiment of the application, the operating power of the heating tile can be determined by the magnitude of the current flowing through it. For example, the processor can calculate the current operating power of the heating tile based on the current magnitude and the resistance of the heating tile.

[0157] Step 303: Determine the current operating status of the thermoforming machine based on the operating power.

[0158] Specifically, the current operating status of the thermoforming machine can be determined based on the ratio between the operating power of the heating tile and its rated operating power. The rated operating power of the heating tile can specifically refer to the operating power when thermoforming the largest mold. For example, when the operating power of the heating tile is 0, meaning no current flows through it, the ratio of its operating power to its rated operating power is 0, indicating that the thermoforming machine is currently in a stopped state.

[0159] Step 304: Adjust the opening degree of the exhaust duct damper 40 and the output power of the induced draft fan 30 according to the current operating status.

[0160] It is understood that in this embodiment, step 304 is the same as or similar to step 203 in the foregoing embodiment of this application. For details, please refer to the detailed description of step 203 in the foregoing embodiment of this application. This embodiment will not repeat the description here.

[0161] In this embodiment, the operating power of the heating tile is determined by the operating parameters of the thermoforming machine. This allows for accurate determination of the current operating status of the thermoforming machine, enabling precise adjustment of the opening of the air valve 40 and the output power of the induced draft fan 30. On the one hand, this reduces unnecessary energy waste, and on the other hand, it ensures the suction force of the thermoforming machine in production, ensuring that the generated VOC gas is completely removed, effectively preventing environmental pollution.

[0162] Figure 4 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application.

[0163] Understandably, during the process of the exhaust fan 30 providing negative pressure to the gas collection hood 10 through the exhaust duct and extracting and treating the VOC gases generated during thermoforming, the flowing gas will carry away some of the heat generated by the heating tiles. Furthermore, in the design of the exhaust ducts, the resistance of each exhaust duct may be inconsistent. Without the damper 40 for resistance adjustment, this can easily lead to excessive exhaust volume in some thermoforming machines, meaning the airflow carries away a significant amount of heat from the thermoforming machine, resulting in substantial energy loss.

[0164] In some optional embodiments of this application, an airflow state monitoring sensor is provided at the connection point between the gas collection hood 10 and the outlet of the thermoforming machine. The airflow state monitoring sensor is used to monitor the airflow state at the outlet of the thermoforming machine. (Refer to...) Figure 4 As shown in the embodiment of this application, the induced draft control method for the thermoforming unit further includes the following steps:

[0165] Step 401: Obtain the operating parameters monitored by the sensors for each operating parameter.

[0166] Step 402: Determine the current operating status of the thermoforming machine based on the operating parameters.

[0167] Step 403: Obtain the airflow state parameters monitored by the airflow state monitoring sensor.

[0168] Specifically, in this embodiment, the airflow state monitoring sensor can monitor airflow velocity and airflow temperature. As a specific example of this embodiment, the airflow state monitoring sensor can be a temperature sensor (e.g., a thermistor) or a wind speed sensor (e.g., a flow meter). In some possible examples, the thermistor and flow meter can be installed at the connection point between the gas collection hood 10 and the outlet of the thermoforming machine. That is, in this embodiment, the airflow state parameters can include gas temperature and gas flow rate.

[0169] In one optional example of the embodiments of this application, the airflow state monitoring sensor further includes a thermal anemometer.

[0170] Step 404: Determine the amount of heat loss generated by the thermoforming machine as it flows with the airflow based on the airflow state parameters.

[0171] Specifically, the VOC gas exhaust concentration generated by the thermoforming machine during thermoforming is not high, usually below 100 ppm. When determining the heat loss caused by the airflow in the thermoforming machine, the airflow containing VOC gas can be approximated as air. Specifically, the heat power of the gas drawn away by the exhaust duct can be calculated according to the following formula (1):

[0172] Q = C k *Vk *(T pf -T lk ) / 3600 (1)

[0173] In the formula: Q is the heat power carried away by the gas, and the unit is: kW, which is the amount of heat loss generated by the thermoforming machine as the airflow flows.

[0174] C k The specific heat at constant pressure of air, with units of kJ / (m³). 3 The temperature of the exhaust air (℃) can be considered a constant within the exhaust temperature range of the thermoforming machine.

[0175] V k The measured exhaust flow rate within the duct is expressed in m³ / s. 3 / h;

[0176] T pf The temperature of the exhaust air at the outlet of the thermoforming machine was measured in °C.

[0177] T lk The ambient cold air temperature in the thermoforming workshop is expressed in °C.

[0178] Step 405: Adjust the opening of the exhaust duct valve 40 and the output power of the induced draft fan 30 according to the current operating status and heat loss.

[0179] It is understandable that, to avoid excessive energy loss, the heat carried away by the exhaust fan from the thermoforming machine needs to be controlled within a certain range. To ensure complete removal of VOC gases, the heat loss caused by the exhaust fan 30 is typically controlled within 20%-25%. In this embodiment, by adjusting the opening of the exhaust valve 40 and the output power of the exhaust fan 30 based on the current operating status and heat loss of the thermoforming machine, the heat loss of the thermoforming machine can be effectively reduced, thus effectively reducing energy consumption.

[0180] Figure 5 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application.

[0181] Reference Figure 5 As shown, in some optional examples of embodiments of this application, the induced draft control method of the thermoforming unit specifically includes the following steps:

[0182] Step 501: Obtain the operating parameters monitored by the sensors for each operating parameter.

[0183] Step 502: Determine the current operating status of the thermoforming machine based on the operating parameters.

[0184] Step 503: Obtain the airflow state parameters monitored by the airflow state monitoring sensor.

[0185] Step 504: Determine the amount of heat loss generated by the thermoforming machine as it flows with the airflow based on the airflow state parameters.

[0186] Step 505: Determine the exhaust heat dissipation coefficient of the thermoforming machine based on the operating power and heat loss.

[0187] Specifically, the exhaust heat dissipation coefficient can be the ratio of the operating power of the heating tile (i.e., the electrical power of the heating tile calculated based on the current as described in the foregoing embodiments of this application) to the amount of heat loss.

[0188] As a specific example, in this embodiment of the application, the current exhaust heat dissipation coefficient of the thermoforming machine can be calculated and determined according to the following formula (2):

[0189] H = P / Q (2)

[0190] In the formula: H is the exhaust heat dissipation coefficient;

[0191] P is the operating power of the heating tile;

[0192] Q represents the thermal power of the gas drawn away by the exhaust duct as described in the foregoing embodiments of this application.

[0193] Step 506: Determine whether the exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range.

[0194] Specifically, referring to the detailed description of the foregoing embodiments of this application, the heat loss caused by the exhaust fan 30 is typically controlled within the range of 20%-25%, that is, the preset exhaust heat dissipation coefficient can usually be set within the range of 4 to 5. This ensures that VOC gas is completely extracted without causing a large loss of heat from the thermoforming machine, thereby reducing energy consumption.

[0195] It is understandable that when the exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range, that is, when the calculated exhaust heat dissipation coefficient of the current thermoforming machine is in the range of 4 to 5, it means that the current exhaust volume can completely remove the VOC gas and will not cause a large heat loss to the thermoforming machine. At this time, the opening of the air valve 40 and the output power of the induced draft fan 30 can remain unchanged.

[0196] Step 507: If the exhaust heat dissipation coefficient exceeds the preset exhaust heat dissipation coefficient range, adjust the opening of the air valve 40 and the output power of the induced draft fan 30.

[0197] Specifically, in the embodiments of this application, the exhaust heat dissipation system exceeding the preset exhaust heat dissipation coefficient range can specifically mean that the current exhaust heat dissipation coefficient of the thermoforming machine is greater than the upper limit of the preset exhaust heat dissipation coefficient (for example, the current exhaust heat dissipation coefficient is greater than 5), or the current exhaust heat dissipation coefficient of the thermoforming machine is less than the lower limit of the preset exhaust heat dissipation coefficient (for example, the current exhaust heat dissipation coefficient is less than 4).

[0198] It is understandable that when the current exhaust heat dissipation coefficient of the thermoforming machine is greater than the upper limit of the preset exhaust heat dissipation coefficient, it indicates that the amount of heat loss of the thermoforming machine carried away by the induced draft fan 30 is small, that is, the suction force of the induced draft fan 30 on the thermoforming machine is insufficient, which may cause VOC gas to not be discharged in time, posing a certain risk of environmental pollution. At this time, it is necessary to increase the opening of the air valve 40 and the output power of the induced draft fan 30.

[0199] It is also understandable that when the current exhaust heat dissipation coefficient of the thermoforming machine is less than the lower limit of the preset exhaust heat dissipation coefficient, it indicates that the heat loss of the thermoforming machine carried away by the induced draft fan 30 is large, that is, the suction force of the induced draft fan 30 on the thermoforming machine is too large. At this time, there is excess exhaust volume and a certain amount of energy waste. At this time, it is necessary to reduce the opening of the air valve 40 and the output power of the induced draft fan 30.

[0200] In this embodiment of the application, by comparing the exhaust heat dissipation coefficient of the thermoforming machine with the preset exhaust heat dissipation coefficient, the heat loss of the thermoforming machine can be effectively controlled within a suitable range, ensuring that all VOC gases generated during the thermoforming process are extracted. At the same time, it can reduce heat loss during the thermoforming process and reduce energy consumption.

[0201] In addition, by setting up an airflow state monitoring sensor to monitor airflow state parameters, it is possible to determine the heat loss caused to the thermoforming machine when the induced draft fan 30 is working. When adjusting the opening of the air valve 40 and the output power of the induced draft fan 30, the opening of the air valve 40 and the output power of the induced draft fan 30 can also be adjusted according to the current operating status of the thermoforming machine and the heat loss. This ensures that the adjusted output power of the induced draft fan 30 will not cause excessive heat loss to the thermoforming machine, and can effectively save energy consumption.

[0202] Figure 6 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application.

[0203] In some other optional examples of the embodiments of this application, refer to Figure 6 As shown, in some optional examples of embodiments of this application, the induced draft control method of the thermoforming unit specifically includes the following steps:

[0204] Step 601: Obtain the operating parameters monitored by the sensors for each operating parameter.

[0205] Step 602: Determine the current operating status of the thermoforming machine based on the operating parameters.

[0206] Step 603: Obtain the airflow state parameters monitored by the airflow state monitoring sensor.

[0207] Step 604: Determine the amount of heat loss generated by the thermoforming machine as it flows with the airflow based on the airflow state parameters.

[0208] Step 605: Determine the exhaust heat dissipation coefficient of the thermoforming machine based on the operating power and heat loss.

[0209] Step 606: When the exhaust heat dissipation coefficient is greater than or equal to the first preset threshold, adjust the opening of the first regulating circulation regulating air valve 40 and the output power of the induced draft fan 30 until the exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range.

[0210] It is understood that in the embodiments of this application, the first preset threshold can be the upper limit threshold of the exhaust heat dissipation coefficient range described in the foregoing embodiments of this application (for example, the upper limit threshold 5, that is, the heat power carried away by the current exhaust volume of the thermoforming machine accounts for less than 20% of the operating power of the heating tile).

[0211] In this embodiment of the application, the first adjustment cycle includes:

[0212] Step 6061: Increase the opening of the air valve 40 by the first opening adjustment value.

[0213] Specifically, in this embodiment, the first opening adjustment value can be represented by the rotation angle of the baffle of the damper 40. For example, the first opening adjustment value can be a rotation of 2°, 5°, or 10°. It is understood that in this embodiment, the rotation angle of the baffle is only shown as a specific example and is not intended to limit the specific value of the first opening adjustment. In some possible examples, the first opening adjustment value can be set according to the actual working conditions.

[0214] In some possible examples, the first opening adjustment value can also be expressed as a percentage when the damper is fully open at 40%, for example, the first opening adjustment value can be 5%, 10%, or 15%, etc.

[0215] Step 6062: Increase the output power of the induced draft fan 30 by the first power adjustment value, so as to increase the exhaust volume in the main air duct 60 by the first preset exhaust volume.

[0216] It is understood that in this embodiment, the output power of the induced draft fan 30 can be specifically expressed in terms of the frequency of the inverter. That is, in this embodiment, the first power adjustment value can be the frequency adjustment value of the inverter, which in some specific examples can be 5Hz, 10Hz, or 15Hz, etc. It is also understood that the first power adjustment value can be expressed as a percentage of the rated output power of the induced draft fan 30. For example, the output power of the induced draft fan 30 can be adjusted by 5%, 10%, or 15% of the rated output power of the induced draft fan 30.

[0217] Specifically, in this embodiment, the adjustment of the output power of the induced draft fan 30 can be aimed at increasing the exhaust volume in the main air duct 60 by a first preset exhaust volume. The main air duct 60 can be the air duct formed by the convergence of exhaust pipes from various thermoforming machines. The induced draft fan 30 is located within the main air duct 60 and provides power to the air within the main air duct 60, creating a negative pressure for suction.

[0218] In some specific examples of embodiments of this application, the first preset exhaust volume can be 80m³. 3 / h、100m 3 / h or 120m 3 / h.

[0219] It should be noted that the numerical values ​​and ranges involved in the embodiments of the present invention are approximate values. Due to the influence of the manufacturing process, there may be a certain range of errors, which can be considered negligible by those skilled in the art.

[0220] In this embodiment of the application, it should also be noted that there is no restriction on the order of execution between steps 6051 and 6052. That is to say, as described in detail in the foregoing embodiments of the application, there is no restriction on the order of adjusting the opening of the air valve 40 and adjusting the output power of the induced draft fan 30. The opening of the air valve 40 can be adjusted first, or the output power of the induced draft fan 30 can be adjusted first.

[0221] Step 6063: Determine whether the current exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range.

[0222] Specifically, in this embodiment, step 6053 is the same as or similar to step 505 in the previous embodiment of this application. For details, please refer to the detailed description of step 505 in the previous embodiment of this application. This embodiment will not repeat the description here.

[0223] In this embodiment, the opening degree of the air valve 40 and the output power of the induced draft fan 30 are adjusted through the first adjustment cycle, which can avoid the situation where the adjustment range of the opening degree of the air valve 40 and the output power of the induced draft fan 30 is too large, effectively reducing the number of adjustments and improving the adjustment efficiency.

[0224] Continue to refer to Figure 6 As shown, in some optional examples of embodiments of this application, the induced draft control method for the thermoforming unit further includes:

[0225] Step 607: When the exhaust heat dissipation coefficient is less than or equal to the second preset threshold, adjust the opening of the second regulating circulation regulating air valve 40 and the output power of the induced draft fan 30 until the exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range.

[0226] Specifically, in this embodiment of the application, the second preset threshold is the lower limit threshold of the exhaust heat dissipation coefficient range (for example, the lower limit threshold 4, that is, the heat power carried away by the current exhaust volume of the thermoforming machine accounts for more than 25% of the operating power of the heating tile).

[0227] In this embodiment of the application, the second adjustment cycle includes:

[0228] Step 6071: Reduce the opening of the air valve 40 by the second opening adjustment value.

[0229] Specifically, in this embodiment, the second opening adjustment value may be the same as or similar to the first opening adjustment value in the foregoing embodiments of this application. For details, please refer to the detailed description of the first opening adjustment value in the foregoing embodiments of this application. This will not be repeated in this embodiment.

[0230] Step 6072: Reduce the output power of the induced draft fan 30 by the second power adjustment value, so as to reduce the exhaust volume in the main air duct 60 by the second preset exhaust volume.

[0231] It is understood that in the embodiments of this application, the second power adjustment value may be the same as or similar to the first power adjustment value described in the foregoing embodiments of this application; in addition, the second preset exhaust volume may be the same as or similar to the first preset exhaust volume described in the foregoing embodiments of this application. For details, please refer to the detailed description of the foregoing embodiments of this application. This will not be repeated in the embodiments of this application.

[0232] Step 6073: Determine whether the current exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range.

[0233] In this embodiment, the opening degree of the air valve 40 and the output power of the induced draft fan 30 are adjusted through the first adjustment cycle and the second adjustment cycle, thereby ensuring that the exhaust volume can completely remove VOC gas without causing excessive heat loss in the thermoforming machine, which can effectively reduce energy consumption and avoid environmental pollution.

[0234] Figure 7 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application.

[0235] In one optional example of the embodiments of this application, refer to Figure 7 As shown, the induced draft control method for the thermoforming unit includes the following steps: The thermoforming machine has a manual / automatic switch, and the operating parameters include the on / off state of the manual / automatic switch.

[0236] Step 701: Obtain the switching signal of the manual / automatic switch.

[0237] Specifically, when the thermoforming machine switches between manual and automatic modes, the manual / automatic switch triggers a switching signal and sends the switching signal to the processor described in the foregoing embodiments of this application.

[0238] Step 702: Determine whether the current operating state is standby state based on the switch input.

[0239] Specifically, in this embodiment, when the switch signal indicates that the thermoforming machine is in manual mode, it means that the current operating state of the thermoforming machine is standby mode. It is understood that when performing maintenance or mold replacement on the thermoforming machine, it is usually necessary to switch it to manual mode, i.e., the switch signal of the manual / automatic switch indicates that the thermoforming machine is in manual mode. At this time, although the heating element of the thermoforming machine is in heating mode, the operating power of the heating element is low; the demand for exhaust volume is also low.

[0240] Step 703: When the current operating state is standby, adjust the opening of the air valve 40 and the output power of the induced draft fan 30 so that the exhaust volume of the exhaust duct is 10%-20% of the rated exhaust volume.

[0241] In this embodiment, the rated exhaust volume is the exhaust volume in the exhaust duct when all thermoforming machines are in production and the induced draft fan 30 is running at rated power.

[0242] In specific adjustments, the opening degree of the damper 40 can be adjusted to 10%-20% of its fully open state, and the output power of the induced draft fan 30 can be adjusted accordingly. In some specific examples, the opening degree of the damper 40 can be adjusted to 10%, 15%, or 20% of its fully open state, etc. It is understood that the opening degree of the damper 40 in this embodiment is only shown as a specific example and is not a specific limitation on the opening degree of the damper 40.

[0243] It is understood that when the switch signal of the thermoforming machine indicates that the thermoforming machine is in automatic mode, it means that the thermoforming machine is in production mode. Specifically, the opening degree of the air valve 40 and the power of the induced draft fan 30 can be adjusted according to the adjustment method in the aforementioned embodiment of this application. This embodiment of the application will not elaborate on this further.

[0244] In this embodiment, the manual / automatic switch signal of the thermoforming machine is acquired to determine whether the thermoforming machine is in standby mode. For the thermoforming machine in standby mode, the opening of the air valve 40 and the power of the exhaust fan 30 are adjusted to maintain 10%-20% of the rated air volume in the exhaust duct 20. This ensures basic ventilation for the thermoforming machine. In addition, it reduces the leakage of negative pressure provided by the exhaust fan 30 from the thermoforming machine in standby mode, thereby effectively reducing the output power of the exhaust fan 30 and reducing energy loss.

[0245] Figure 8 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application.

[0246] In some optional examples of embodiments of this application, a relay fan 50 is provided in the exhaust duct. The induced draft control method for the thermoforming unit includes the following steps:

[0247] Step 801: Obtain the operating parameters monitored by the sensors for each operating parameter.

[0248] Step 802: Determine the current operating status of the thermoforming machine based on the operating parameters.

[0249] Step 803: Adjust the opening degree of the exhaust duct damper 40 and the output power of the relay fan 50 according to the current operating status.

[0250] It is understood that in the embodiments of this application, the adjustment method of the relay fan 50 can be the same as or similar to the adjustment method of the induced draft fan 30 in the foregoing embodiments of this application. For example, the output power of the relay fan 50 can be adjusted by adjusting the frequency converter corresponding to the relay fan 50.

[0251] It should be noted that in this embodiment, before adjusting the output power of the relay fan 50, the processor can also obtain the switching signals of the relay fans 50 in each exhaust duct 20 and adjust the relay fans 50 according to the switching signals. For example, when the switching signal of the relay fan 50 is off and it is necessary to increase the exhaust volume in the exhaust duct, the relay fan 50 can be turned on, and the output power of the relay fan 50 can be gradually increased in the same way as the adjustment of the induced draft fan 30. As another example, when the switching signal of the relay fan 50 is on and it is running at full power, the output power of the relay fan 50 can be gradually decreased in the same way as the adjustment of the induced draft fan 30 until the switching signal of the relay fan 50 is off.

[0252] In this embodiment, by installing a relay fan 50 in the exhaust duct and adjusting the opening of the air valve 40 and the output power of the relay fan 50 according to the current operating status, the impact on the exhaust volume of other thermoforming machines can be reduced, ensuring the independence of exhaust volume adjustment.

[0253] Figure 9 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application.

[0254] Reference Figure 9 As shown, in some optional examples of embodiments of this application, the induced draft control method of the thermoforming unit includes the following steps:

[0255] Step 901: Obtain the operating parameters monitored by the sensors for each operating parameter.

[0256] Step 902: Determine the current operating status of the thermoforming machine based on the operating parameters.

[0257] Step 903: Adjust the opening of the exhaust duct damper 40, the output power of the relay fan 50, and the output power of the induced draft fan 30 according to the current operating status.

[0258] In other words, in this embodiment of the application, the opening degree of the air valve 40, the output power of the relay fan 50, and the output power of the induced draft fan 30 can also be adjusted simultaneously according to the current operating status of the thermoforming machine.

[0259] It is understood that, in the embodiments of this application, the adjustment of the opening degree of the air valve 40, the output power of the relay fan 50 and the output power of the induced draft fan 30 can be referred to the detailed description of the foregoing embodiments of this application, and will not be repeated in the embodiments of this application.

[0260] Figure 10 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application.

[0261] In one optional example of the embodiments of this application, refer to Figure 1 As shown, all exhaust ducts converge and connect to the main air duct 60. A micro-differential pressure sensor (not shown in the figure) is installed inside the main air duct 60 to monitor the static pressure parameters within the main air duct 60. (Refer to...) Figure 10 As shown in the embodiment of this application, the induced draft control method for a thermoforming unit includes the following steps:

[0262] Step 1001: Obtain the reference negative pressure setting value within the main air duct 60.

[0263] Specifically, in the embodiments of this application, the reference negative pressure setting value can be set according to the actual thermoforming working conditions or the required working conditions.

[0264] As a specific example of an embodiment of this application, specifically, when all thermoforming machines are in full production and the induced draft fan 30 is running at its rated power (e.g., the frequency converter of the induced draft fan 30 is running at 48Hz or 50Hz), the micro differential pressure sensor monitors the negative pressure value in the main air duct 60; the micro differential pressure sensor transmits the monitored negative pressure value to the processor described in the foregoing embodiments of this application, and the processor determines the current negative pressure value in the main air duct 60 as the reference negative pressure setting value.

[0265] Step 1002: Obtain the operating parameters monitored by the sensors for each operating parameter.

[0266] Step 1003: Determine the current operating status of the thermoforming machine based on the operating parameters.

[0267] Step 1004: Adjust the opening of the air valve 40 according to the current operating status.

[0268] Step 1005: Obtain the current negative pressure value in the main air duct 60 monitored by the micro differential pressure sensor.

[0269] It is understandable that adjusting the opening of the damper 40 results in different resistances to the airflow; that is, the negative pressure value within the main air duct 60 changes. For example, when the opening of the damper 40 decreases, the resistance provided by the damper 40 to the airflow increases. With the output power of the induced draft fan 30 remaining constant, the negative pressure within the main air duct 60 increases. At this time, the suction force of the thermoforming machine, for which the openings of other dampers 40 have not been adjusted, is excessive, and the induced draft fan 30 wastes some energy, requiring adjustment of the output power of the induced draft fan 30.

[0270] Step 1006: Adjust the output power of the induced draft fan 30 according to the current negative pressure value and the reference negative pressure setting value, so that the negative pressure value in the main air duct 60 is maintained at the reference negative pressure setting value.

[0271] In other words, in this embodiment of the application, when adjusting the output power of the induced draft fan 30, the adjustment can be made based on the current negative pressure value in the main air duct 60 monitored by the micro differential pressure sensor.

[0272] Specifically, in this embodiment of the application, the micro differential pressure sensor can transmit the real-time negative pressure value monitored in the main air duct 60 to the processor. The processor will compare the real-time negative pressure value with the reference negative pressure setting value until the real-time negative pressure value is the same as the reference negative pressure setting value, or the real-time negative pressure value and the reference negative pressure setting value are within the allowable error range.

[0273] In this embodiment of the application, by setting a reference negative pressure setting value for the main air duct 60, the negative pressure value in the main air duct 60 can be stably adjusted to the reference negative pressure setting value when adjusting the output power of the induced draft fan 30; that is, constant pressure adjustment is adopted, which can effectively reduce the energy loss of the induced draft fan 30 and effectively save energy consumption.

[0274] Figure 11 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application.

[0275] Understandable, refer to Figure 1 As shown, when setting up exhaust ducts, the pipe structure resistance of each exhaust duct may be different, and there may be a certain throttling loss in the exhaust duct.

[0276] Reference Figure 11 In some optional examples of embodiments of this application, the induced draft control method for the thermoforming unit specifically includes the following steps:

[0277] Step 1101: Obtain the reference negative pressure setting value within the main air duct 60.

[0278] Step 1102: Obtain the operating parameters monitored by the sensors for each operating parameter.

[0279] Step 1103: Determine the current operating status of the thermoforming machine based on the operating parameters.

[0280] Step 1104: Adjust the opening of the air valve 40 according to the current operating status.

[0281] Step 1105: Obtain the current negative pressure value in the main air duct 60 monitored by the micro differential pressure sensor.

[0282] Step 1106: Adjust the output power of the induced draft fan 30 according to the current negative pressure value and the reference negative pressure setting value, so that the negative pressure value in the main air duct 60 is maintained at the reference negative pressure setting value.

[0283] Step 1107: Obtain the average opening value of each air valve 40 within the first preset time length.

[0284] Specifically, in the embodiments of this application, the first preset time length can be 30s, 45s, 1min, 1.5min, etc. As a specific example, the first preset time length can be 1min.

[0285] It is understood that the opening degree of the damper 40 may be adjusted or may remain unchanged within the first preset time period. In this embodiment, the average opening degree of the damper 40 within the first preset time period is obtained. Specifically, the average opening degree of the damper 40 within the first preset time period can be determined by whether the damper 40 is activated and the amount of rotation of the drive component after the damper 40 is activated.

[0286] Step 1108: Determine whether the average opening value of all valves is less than or equal to the preset opening threshold of valve 40.

[0287] Specifically, in this embodiment, the preset opening threshold of the air valve 40 can be 60%, 70%, 75%, or 80% of the fully open air valve 40. It can be understood that the preset opening threshold of the air valve 40 can be determined based on the thermoforming conditions. In a specific example, 70% of the fully open air valve 40 can be used as the preset opening threshold.

[0288] Step 1109: If any average opening value is greater than the preset opening threshold of the air valve 40, adjust the output power of the induced draft fan 30 in the third adjustment cycle until all average opening values ​​are less than or equal to the preset opening threshold of the air valve 40.

[0289] In other words, in this embodiment, if the average opening value of any one of the dampers 40 is greater than the preset opening value of the damper 40 (for example, if the average opening value of one damper 40 is greater than 70% of its full opening), it indicates that the damper 40 needs to be at a larger opening to maintain the negative pressure value in the main air duct 60 at the baseline negative pressure setting value. This means the fan's output power is too high, resulting in some energy waste, and the required airflow needs to be met by throttling the damper 40, i.e., reducing the opening of the damper 40. It can be understood that reducing the opening of the damper 40 increases the negative pressure in the main air duct 60. In this embodiment, the output power of the induced draft fan 30 is adjusted using a third adjustment cycle.

[0290] Specifically, the third regulatory cycle includes:

[0291] Step 1109a: Reduce the output power of the induced draft fan 30 so that the negative pressure value of the main air duct 60 is reduced by the first preset pressure adjustment value.

[0292] Specifically, in this embodiment, the adjustment of the output power of the induced draft fan 30 can refer to the adjustment method in the foregoing embodiments of this application. In some specific examples, when reducing the output power of the induced draft fan 30, the negative pressure value monitored by the micro differential pressure sensor in the main air duct 60 can be obtained in real time, and the adjustment of the output power of the induced draft fan 30 can be paused when the change value of the negative pressure value reaches the first preset pressure adjustment.

[0293] In some optional examples, the first preset pressure adjustment value can be 3%, 5%, or 7% of the current negative pressure value, etc. As a specific example, the first preset pressure adjustment value can be 5% of the current negative pressure value.

[0294] Step 1109b: Maintain the current negative pressure value in the main air duct 60 for a second preset time length, and obtain the average opening value of each air valve 40 within the second preset time length.

[0295] Specifically, in this embodiment, the second preset time length can be the same as the first preset time length. For details, please refer to the detailed description of the first preset time length in the foregoing embodiments of this application. In this embodiment, it will not be repeated.

[0296] Step 1109c: Determine whether the average opening value of all valves is less than or equal to the preset opening threshold of valve 40 under the current negative pressure value.

[0297] In this embodiment of the application, by determining the average opening value of each air valve 40 within a first preset time length, and judging whether the average opening value of the largest air valve 40 is less than or equal to the preset opening threshold of the air valve 40, the influence of different exhaust duct structure resistance on exhaust volume can be reduced, and energy consumption can be effectively saved.

[0298] In some optional examples of embodiments of this application, a wind speed monitor is installed on one edge of the gas collection hood 10 facing the thermoforming machine. The wind speed monitor is used to monitor the wind speed at the far edge of the gas collection hood 10.

[0299] It is understandable that when extracting VOC gas, in order to avoid VOC gas leakage and environmental pollution, the inlet of the gas collection hood 10 is usually required to have a certain wind speed. In this embodiment, a wind speed monitor is installed on the edge of the gas collection hood 10 facing the thermoforming machine. In this way, the wind speed at the farthest edge of the gas collection hood 10 can be monitored, which can avoid the situation where the wind speed is too low when adjusting the output power of the induced draft fan 30.

[0300] Figure 12 This is another implementation flowchart of the induced draft control method for the thermoforming unit provided in the embodiments of this application.

[0301] Specifically, refer to Figure 12 As shown, in an optional example of an embodiment of this application, the induced draft control method for a thermoforming unit includes the following steps:

[0302] Step 1201: Obtain the reference negative pressure setting value within the main air duct 60.

[0303] Step 1202: Obtain the operating parameters monitored by the sensors for each operating parameter.

[0304] Step 1203: Determine the current operating status of the thermoforming machine based on the operating parameters.

[0305] Step 1204: Adjust the opening of the air valve 40 according to the current operating status.

[0306] Step 1205: Obtain the current negative pressure value in the main air duct 60 monitored by the micro differential pressure sensor.

[0307] Step 1206: Adjust the output power of the induced draft fan 30 according to the current negative pressure value and the reference negative pressure setting value, so that the negative pressure value in the main air duct 60 is maintained at the reference negative pressure setting value.

[0308] Step 1207: Obtain the average opening value of each air valve 40 within the first preset time length.

[0309] Step 1208: Determine whether the average opening value of all valves is less than or equal to the preset opening threshold of valve 40.

[0310] Step 1209: Obtain the wind speed corresponding to the thermoforming machine in production.

[0311] Specifically, in this embodiment, each thermoforming machine's vent 10 is equipped with a corresponding wind speed monitor. In practice, each wind speed monitor can report a detected wind speed value to the processor. In this embodiment, the processor can discharge wind speeds below a certain threshold. For example, for a thermoforming machine in a stopped state, the corresponding air valve 40 is closed, and the wind speed value is typically 0; for a thermoforming machine in standby state, the wind speed is typically 10%-20% of the rated wind speed. Therefore, in this embodiment, wind speed values ​​below 10% of the rated wind speed can be first excluded, and only the wind speed corresponding to the thermoforming machine in production state can be obtained.

[0312] Step 1210: Determine whether all wind speeds are less than or equal to the preset wind speed threshold.

[0313] Specifically, in this embodiment, the preset wind speed threshold can be the minimum wind speed requirement for VOC exhaust. In some specific examples, the preset wind speed threshold can be 0.3 m / s, 0.31 m / s, or 0.32 m / s. It is understood that the preset wind speed threshold in this embodiment is only shown as a specific example, and in some specific examples, the preset wind speed threshold can be set to any value greater than 0.3 m / s.

[0314] Step 1211: When all wind speeds are greater than the preset wind speed threshold, adjust the output power of the induced draft fan 30 using the third adjustment cycle.

[0315] In this embodiment, by installing a wind speed monitor on the edge of the gas collection hood 10 facing the thermoforming machine, the wind speed is determined before adjusting the output power of the induced draft fan 30. This ensures that the suction force of the thermoforming machine in production meets the minimum wind speed requirement, effectively ensuring the complete removal of VOC gas and effectively avoiding environmental pollution.

[0316] Figure 13 This is a flowchart illustrating one implementation of the induced draft control method for a thermoforming unit provided in this application embodiment.

[0317] Reference Figure 13 As shown, in some optional examples of embodiments of this application, the induced draft control method of the thermoforming unit specifically includes the following steps:

[0318] Step 1301: Obtain the reference negative pressure setting value within the main air duct 60.

[0319] Step 1302: Obtain the operating parameters monitored by the sensors for each operating parameter.

[0320] Step 1303: Determine the current operating status of the thermoforming machine based on the operating parameters.

[0321] Step 1304: Adjust the opening of the air valve 40 according to the current operating status.

[0322] Step 1305: Obtain the current negative pressure value in the main air duct 60 monitored by the micro differential pressure sensor.

[0323] Step 1306: Adjust the output power of the induced draft fan 30 according to the current negative pressure value and the reference negative pressure setting value, so that the negative pressure value in the main air duct 60 is maintained at the reference negative pressure setting value.

[0324] Step 1307: Obtain the average opening value of each air valve 40 within the first preset time length.

[0325] Step 1308: Determine whether the average opening value of all valves is less than or equal to the preset opening threshold of valve 40.

[0326] Step 1309: Obtain the wind speed corresponding to the thermoforming machine in production.

[0327] Step 1310: Determine whether all wind speeds are less than or equal to the preset wind speed threshold.

[0328] Step 1311: When at least one wind speed is less than or equal to a preset wind speed threshold, adjust the output power of the induced draft fan 30 using a fourth adjustment cycle until all wind speeds are greater than the preset wind speed threshold; wherein, the fourth adjustment cycle includes:

[0329] Step 1311a: Increase the output power of the induced draft fan 30 so that the negative pressure value of the main air duct 60 increases by the second preset pressure adjustment value.

[0330] Specifically, in this embodiment, the second preset pressure adjustment value can be the same as the first preset pressure adjustment value described in the foregoing embodiments of this application. Specifically, it can be referred to the adjustment method for reducing the output power of the induced draft fan 30 in the foregoing embodiments of this application, which will not be repeated in this embodiment.

[0331] Step 1311b: Determine whether any of the current wind speeds are less than or equal to a preset wind speed threshold.

[0332] In this embodiment, by installing a wind speed monitor on the edge of the gas collection hood 10 facing the thermoforming machine, the wind speed is determined before adjusting the output power of the induced draft fan 30. This ensures that the suction force of the thermoforming machine in production meets the minimum wind speed requirement, effectively ensuring the complete removal of VOC gas and effectively avoiding environmental pollution.

[0333] Figure 14 This is a structural block diagram of the induced draft control device for the thermoforming unit provided in the embodiments of this application.

[0334] Reference Figure 14 As shown in the embodiment of this application, an induced draft control device 140 for a thermoforming unit is also provided, comprising:

[0335] The acquisition module 141 is used to acquire the operating parameters monitored by various operating parameter sensors.

[0336] The determination module 142 is used to determine the current operating status of the thermoforming machine based on the operating parameters obtained by the acquisition module 141. The current operating status is used to characterize the amount of volatile organic compounds released during thermoforming.

[0337] The adjustment module 143 is used to adjust the opening degree of the air valve 40 of the exhaust duct and the output power of the induced draft fan 30 according to the current operating state determined by the determination module 142. The induced draft fan 30 is connected to the exhaust duct and is used to provide negative pressure to the exhaust duct.

[0338] Specifically, the induced draft control device embodiment of this application has the same or corresponding technical effects as the induced draft control method embodiment of the aforementioned application. For details, please refer to the detailed description of the induced draft control method in the aforementioned embodiments of this application. This will not be repeated in the embodiments of this application.

[0339] On the other hand, embodiments of this application provide a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions, and when the program instructions are executed by a computer, the computer can perform the methods provided in the above-described method embodiments, such as including:

[0340] Obtain the operating parameters monitored by the sensors for each operating parameter.

[0341] Determine the current operating status of the thermoforming machine based on the operating parameters.

[0342] Adjust the opening degree of the exhaust valve 40 and the output power of the induced draft fan 30 according to the current operating status.

[0343] In another aspect, embodiments of this application also provide a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, is implemented to perform the transmission methods provided in the above embodiments, including, for example:

[0344] Obtain the operating parameters monitored by the sensors for each operating parameter.

[0345] Determine the current operating status of the thermoforming machine based on the operating parameters.

[0346] Adjust the opening degree of the exhaust valve 40 and the output power of the induced draft fan 30 according to the current operating status.

[0347] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0348] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of software products. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0349] Finally, it should be noted that the above embodiments are only used to illustrate this application and are not intended to limit this application. Although this application has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of this application do not depart from the spirit and scope of the technical solutions of this application and should all be covered within the protection scope of this application.

Claims

1. A method for controlling the induced draft of a thermoforming unit, characterized in that, The thermoforming unit includes multiple thermoforming machines, each of which is equipped with a vent hood and an operating parameter sensor. The vent hood is connected to an exhaust duct, and the operating parameter sensor is used to monitor the operating parameters of the thermoforming machine. The method includes: The operating parameters monitored by each of the aforementioned operating parameter sensors are acquired; Based on the operating parameters, the current operating state of the thermoforming machine is determined, and the current operating state is used to characterize the amount of volatile organic compounds released during thermoforming. Based on the current operating status, adjust the opening of the air valve in the exhaust duct and the output power of the induced draft fan. The induced draft fan is connected to the exhaust duct and is used to provide negative pressure to the exhaust duct. All the aforementioned exhaust ducts converge and connect to a main air duct, which is equipped with a micro differential pressure sensor for monitoring the static pressure parameters within the main air duct; the method further includes: Obtain the reference negative pressure setting value within the main air duct; The step of adjusting the opening degree of the exhaust duct damper and the output power of the induced draft fan according to the current operating state further includes: Adjust the opening degree of the air valve according to the current operating status; Obtain the current negative pressure value in the main air duct monitored by the micro differential pressure sensor; The output power of the induced draft fan is adjusted according to the current negative pressure value and the reference negative pressure setting value so that the negative pressure value in the main air duct is maintained at the reference negative pressure setting value.

2. The induced draft control method for the thermoforming unit according to claim 1, characterized in that, The step of determining the current operating status of the thermoforming machine based on the operating parameters includes: Based on the operating parameters, determine the operating power of the heating tile of the thermoforming machine; The current operating status of the thermoforming machine is determined based on the operating power.

3. The induced draft control method for the thermoforming unit according to claim 2, characterized in that, An airflow state monitoring sensor is installed at the connection point between the gas collection hood and the outlet of the thermoforming machine. The airflow state monitoring sensor is used to monitor the airflow state at the outlet of the thermoforming machine. After the step of determining the current operating state of the thermoforming machine based on the operating power, the method further includes: Obtain the airflow state parameters monitored by the airflow state monitoring sensor; Based on the airflow state parameters, determine the amount of heat loss generated by the thermoforming machine as it flows with the airflow; The step of adjusting the opening degree of the exhaust duct damper and the output power of the induced draft fan according to the current operating state includes: Based on the current operating status and the amount of heat loss, adjust the opening of the exhaust duct valve and the output power of the induced draft fan.

4. The induced draft control method for the thermoforming unit according to claim 3, characterized in that, The step of adjusting the opening of the exhaust duct damper and the output power of the induced draft fan according to the current operating status and the heat loss includes: The exhaust heat dissipation coefficient of the thermoforming machine is determined based on the operating power and the heat loss. Determine whether the exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range; If the exhaust heat dissipation coefficient exceeds the preset exhaust heat dissipation coefficient range, adjust the opening of the air valve and the output power of the induced draft fan.

5. The induced draft control method for the thermoforming unit according to claim 4, characterized in that, The step of adjusting the opening of the air valve and the output power of the induced draft fan when the exhaust heat dissipation coefficient exceeds the preset exhaust heat dissipation coefficient range includes: When the exhaust heat dissipation coefficient is greater than or equal to a first preset threshold, the opening of the air valve and the output power of the induced draft fan are adjusted in a first adjustment cycle until the exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range, where the first preset threshold is the upper limit of the exhaust heat dissipation coefficient range; wherein, the first adjustment cycle includes: Increase the opening of the air valve by the first opening adjustment value; The output power of the induced draft fan is increased by a first power adjustment value, so that the exhaust volume in the main air duct increases by a first preset exhaust volume. Determine whether the current exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range.

6. The induced draft control method for the thermoforming unit according to claim 5, characterized in that, The step of adjusting the opening of the air valve and the output power of the induced draft fan when the exhaust heat dissipation coefficient exceeds the preset exhaust heat dissipation coefficient range further includes: When the exhaust heat dissipation coefficient is less than or equal to a second preset threshold, the opening of the air valve and the output power of the induced draft fan are adjusted in a second adjustment cycle until the exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range, where the second preset threshold is the lower limit of the exhaust heat dissipation coefficient range; wherein, the second adjustment cycle includes: The opening of the air valve is reduced by the second opening adjustment value; The output power of the induced draft fan is reduced by the second power adjustment value, so that the exhaust volume in the main air duct is reduced by the second preset exhaust volume. Determine whether the current exhaust heat dissipation coefficient is within the preset exhaust heat dissipation coefficient range.

7. The induced draft control method for the thermoforming unit according to claim 3, characterized in that, The airflow state monitoring sensor includes a thermal anemometer, and the airflow state parameters include wind speed and airflow temperature.

8. The induced draft control method for a thermoforming unit according to any one of claims 2-7, characterized in that, The thermoforming machine is equipped with a current monitoring sensor, which is used to monitor the magnitude of the current flowing through the heating tile; Determining the operating power of the heating tile of the thermoforming machine based on the operating parameters includes: The operating power of the heating tile of the thermoforming machine is determined based on the magnitude of the current.

9. The induced draft control method for the thermoforming unit according to claim 1, characterized in that, The thermoforming machine has a manual / automatic switch, and the operating parameters include the on / off state of the manual / automatic switch; The step of determining the current operating status of the thermoforming machine based on the operating parameters includes: Determine whether the current operating state is a standby state based on the switch quantity; The step of adjusting the opening degree of the exhaust duct damper and the output power of the induced draft fan according to the current operating state includes: When the current operating state is standby, adjust the opening of the air valve and the output power of the induced draft fan so that the exhaust volume of the exhaust duct is 10%-20% of the rated exhaust volume; wherein, the rated exhaust volume is the exhaust volume in the exhaust duct when all the thermoforming machines are in production and the induced draft fan is running at rated power.

10. The induced draft control method for the thermoforming unit according to claim 1, characterized in that, The exhaust duct is equipped with a relay fan; the step of adjusting the opening of the exhaust duct's damper and the output power of the induced draft fan according to the current operating status also includes: Based on the current operating status, adjust the opening of the exhaust duct damper and the output power of the relay fan; or, Based on the current operating status, adjust the opening of the exhaust duct valve, the output power of the relay fan, and the output power of the induced draft fan.

11. The induced draft control method for the thermoforming unit according to claim 1, characterized in that, After the step of adjusting the output power of the induced draft fan according to the current negative pressure value and the reference negative pressure setting value to maintain the negative pressure value in the main air duct at the reference negative pressure setting value, the method further includes: Obtain the average opening value of each of the air valves within a first preset time period; Determine whether the average opening value of all the stated openings is less than or equal to the preset opening threshold of the damper; If any of the average opening values ​​is greater than the preset opening threshold of the air valve, the output power of the induced draft fan is adjusted in a third adjustment cycle until all the average opening values ​​are less than or equal to the preset opening threshold of the air valve; wherein, the third adjustment cycle includes: Reduce the output power of the exhaust fan so that the negative pressure value of the main air duct decreases by a first preset pressure adjustment value; Maintain the current negative pressure value in the main air duct for a second preset time length, and obtain the average opening value of each air valve within the second preset time length; Determine whether the average opening value of all valves is less than or equal to the preset opening threshold of the air valve under the current negative pressure value.

12. The induced draft control method for the thermoforming unit according to claim 11, characterized in that, A wind speed monitor is installed on one edge of the gas collection hood facing the thermoforming machine. The wind speed monitor is used to monitor the wind speed at the far edge of the gas collection hood. Before the step of adjusting the output power of the induced draft fan in a third adjustment cycle until the average value of all the openings is less than or equal to the preset opening threshold of the air valve, the method further includes: Obtain the wind speed corresponding to the thermoforming machine in production status; Determine whether all the wind speeds are less than or equal to a preset wind speed threshold. When all the wind speeds are greater than the preset wind speed threshold, the output power of the induced draft fan is adjusted in the third adjustment cycle.

13. The induced draft control method for the thermoforming unit according to claim 12, characterized in that, The method further includes: If at least one of the wind speeds is less than or equal to the preset wind speed threshold, the output power of the induced draft fan is adjusted in a fourth adjustment cycle until all the wind speeds are greater than the preset wind speed threshold; wherein, the fourth adjustment cycle includes: Increase the output power of the induced draft fan so that the negative pressure value of the main air duct increases by the second preset pressure adjustment value; Determine whether any of the current wind speeds is less than or equal to the preset wind speed threshold.

14. The induced draft control method for the thermoforming unit according to claim 1, characterized in that, The process of obtaining the reference negative pressure setting value within the main air duct includes: With all the aforementioned thermoforming machines operating at full capacity and the induced draft fan running at rated power, the negative pressure value monitored by the micro differential pressure sensor is obtained. The negative pressure value is determined as the reference negative pressure setting value.

15. An induced draft control device for a thermoforming unit, characterized in that, The thermoforming unit includes multiple thermoforming machines, each of which is equipped with a gas collection hood and an operating parameter sensor. The gas collection hood is connected to an exhaust duct, and the operating parameter sensor is used to monitor the operating parameters of the thermoforming machine. The device includes: The acquisition module is used to acquire the operating parameters monitored by each of the operating parameter sensors; The determination module is used to determine the current operating state of the thermoforming machine based on the operating parameters, wherein the current operating state is used to characterize the amount of volatile organic compounds released during thermoforming; The adjustment module is used to adjust the opening degree of the air valve of the exhaust duct and the output power of the induced draft fan according to the current operating status. The induced draft fan is connected to the exhaust duct and is used to provide negative pressure to the exhaust duct. All the aforementioned exhaust ducts converge and connect to the main air duct, which is equipped with a micro differential pressure sensor for monitoring the static pressure parameters within the main air duct; the acquisition module is further configured to: Obtain the reference negative pressure setting value within the main air duct; The adjustment module is also used for: Adjust the opening degree of the air valve according to the current operating status; Obtain the current negative pressure value in the main air duct monitored by the micro differential pressure sensor; The output power of the induced draft fan is adjusted according to the current negative pressure value and the reference negative pressure setting value so that the negative pressure value in the main air duct is maintained at the reference negative pressure setting value.

16. An induced draft control system for a thermoforming unit, characterized in that, include: Multiple thermoforming machines, and sensors for the operating parameters of each thermoforming machine; The operating parameter sensor is used to monitor the operating parameters of the thermoforming machine; Multiple gas collection hoods are provided, and the gas collection hoods are correspondingly arranged with the thermoforming machine; An exhaust duct, wherein the exhaust duct is connected to a plurality of the gas collection hoods; An exhaust fan is connected to the exhaust duct and is used to provide negative pressure to the exhaust duct. A memory that stores computer programs; A processor for executing the computer program to implement the induced draft control method for the thermoforming unit according to any one of claims 1-14.

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