Hot air circulation drying system

Abstract

The utility model discloses a hot air circulation drying system, which belongs to the technical field of wood drying and comprises a drying room, a drying support and a heat pump drying unit, an air supply pipe is laid on the ground in the drying room along the wall of the drying room, and an air feeder of the heat pump drying unit feeds air heated by a condenser into the drying room through the air supply pipe; a partition plate is arranged in the drying room to divide the drying room into an upper layer cavity and a lower layer cavity, at least one row of circulating fans arranged at equal intervals in the left-right direction is installed on the partition plate, and air return holes are evenly distributed in the circulating fans. And the drying bracket is vertically mounted, is placed in the lower-layer cavity and is used for vertically placing the slab. According to the hot air circulation drying system, the space utilization rate and the single-time drying amount are remarkably improved in the mode that the slabs are vertically placed, meanwhile, efficient airflow circulation is formed through reasonable layout of the circulating fan and the drying support, it is guaranteed that hot air is evenly distributed, heat efficiency and drying uniformity are improved, and therefore production efficiency is greatly improved, and production cost is reduced. Energy is saved, and production cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of wood drying technology, and in particular to a hot air circulation drying system for drying wood veneer. Background Technology

[0002] Veneer used in building decoration and furniture production is a thin board with a thickness of 1.5-3.0mm that is rotary cut from wood. The veneer has a high moisture content, usually between 30-80%, and some woods even have a moisture content of over 80%. Therefore, it must be dried before pressing. Veneer drying is an important process in the production of plywood and formwork.

[0003] Traditional drying methods involve placing the sheets on racks for outdoor air drying, but this process is extremely slow, severely limiting work progress and efficiency. The most common artificial drying method currently is oven drying. In this method, the sheets are laid flat on racks, with gaps between them, and then the oven is heated by circulating hot air to dry them. However, this flat-laying method has the following problems: 1. Laying the sheets flat occupies a lot of space, resulting in low space utilization and limited drying capacity per batch; 2. Flat stacking obstructs airflow between the sheets, hindering the upward flow of hot air, resulting in low thermal efficiency and uneven airflow distribution, causing uneven drying between the edges and the center of the sheets, affecting drying quality and increasing energy consumption. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the above-mentioned problems and provide a hot air circulation drying system. By rationally designing the placement method of the sheet metal, the structural layout of the drying room, and the airflow organization method, the system can improve space utilization and drying capacity per cycle, while ensuring that the hot air can be evenly distributed, thereby improving thermal efficiency and drying uniformity, thus increasing production efficiency and saving energy.

[0005] The technical solution of this utility model is:

[0006] A hot air circulating drying system includes a drying chamber, a drying rack installed inside the drying chamber, and a heat pump drying unit installed outside the drying chamber. The heat pump drying unit includes a compressor, an evaporator, a condenser, and a blower. The system is characterized in that: the evaporator and condenser are respectively arranged in a first installation chamber and a second installation chamber; the air inlet of the blower is connected to the second installation chamber; an air supply duct is laid along the walls of the drying chamber on the floor inside the drying chamber; the air supply duct has two air outlets located at the front ends of the left and right side walls respectively; the air outlet of the blower is connected to the air supply duct via a pipe for delivering air heated by the condenser into the drying chamber through the air supply duct.

[0007] The drying room is divided into an upper cavity and a lower cavity by a partition. At least one row of circulating fans are installed on the partition, which are arranged at equal intervals in the left and right direction. The air outlets of the circulating fans are vertically downward. The partition is also evenly covered with return air holes.

[0008] The drying rack is a vertical drying rack used to vertically place the boards. The drying racks are placed in rows along the left and right direction on the floor of the lower cavity of the drying room.

[0009] It also includes a control system, which is electrically connected to the heat pump dryer unit and the circulating fan, and is used to control the operation of the heat pump dryer unit and the circulating fan.

[0010] As an optimization, the aforementioned hot air circulating drying system also includes an electromagnetic heating device, which includes a heating coil, a temperature sensor, and an electromagnetic heater connected to the heating coil. The duct after the air outlet of the blower includes a heating pipe section located adjacent to the air outlet of the blower. The heating coil is wound around the outside of the heating pipe section, and the temperature sensor is located inside the heating pipe section. The electromagnetic heater and the temperature sensor are electrically connected to the control system. The control system controls the operation of the electromagnetic heater and the heating coil according to the temperature sensed by the temperature sensor to assist the heat pump dryer unit in heating the air sent into the drying chamber.

[0011] As an optimization, in the above-mentioned hot air circulating drying system, the drying rack includes a receiving frame for vertically placing the sheet metal and supporting legs connected to the receiving frame. The sheet metal in the receiving frame is placed perpendicular to the left and right direction. Several drying racks are stacked vertically and aligned to form a stack. Horizontal air ducts are formed between the upper and lower drying racks and between the bottom drying rack and the ground. Multiple rows of stacked drying racks are arranged in the drying room, and an aisle is left directly below each row of circulating fans to form the air supply channel of the circulating fans.

[0012] As an optimization, in the above-mentioned hot air circulating drying system, the circulating fans installed on the partition are in a row, located in the middle of the front-to-back direction of the drying chamber; or in two rows, located at the front and rear of the drying chamber respectively.

[0013] As an optimization, in the above-mentioned hot air circulating drying system, each of the circulating fans is provided with a damper below it. The size of the damper is sufficient to cover the installation position of the circulating fan, and the opening and closing of the damper is controlled by the control system.

[0014] As an optimization, in the above-mentioned hot air circulation drying system, a dehumidification port is provided at the lower part of the rear wall of the drying chamber, a dehumidification fan is provided in association with the dehumidification port, and the dehumidification port is connected to the first installation chamber of the evaporator through a pipe.

[0015] As an optimization, in the above-mentioned hot air circulation drying system, the first installation chamber and the second installation chamber are connected, and a guide fan is provided between the two installation chambers to guide the dry air cooled and dehydrated by the evaporator in the first installation chamber to the second installation chamber.

[0016] As an optimization, in the above-mentioned hot air circulation drying system, a dehumidification port communicating with the outside is provided in the middle of the rear wall of the drying chamber, and a dehumidification fan is provided in association with the dehumidification port.

[0017] As an optimization, in the above-mentioned hot air circulation drying system, at least one exhaust port connected to the outside is provided on the upper part of the rear wall of the drying chamber, and an exhaust fan is provided in association with the exhaust port.

[0018] The beneficial effects of this utility model are:

[0019] 1. This hot air circulation drying system adopts a vertical placement of the boards, which significantly improves space utilization and increases the drying capacity per batch. The rational layout of the circulating fan and drying rack forms an efficient airflow circulation path, allowing the hot air to fully diffuse and evenly pass through the gaps between the vertically placed boards to remove moisture from the wood. This reduces airflow resistance, improves thermal efficiency, and ensures drying uniformity, thereby greatly improving production efficiency and drying effect, reducing energy waste, and lowering production costs.

[0020] 2. The electromagnetic heating device is set as an auxiliary heating unit for the heat pump dryer, which effectively makes up for the shortcomings of the heat pump in terms of poor heating effect in low temperature environment or high load conditions. At the same time, with its rapid heating characteristics, it can quickly increase the air temperature in the pipeline at the beginning of system startup, thereby improving the overall heating capacity and working efficiency of the system.

[0021] 3. The damper can effectively close the corresponding airflow channel when some circulating fans stop working, thereby optimizing the hot air circulation path in the drying room, preventing heat loss, improving drying efficiency and reducing energy consumption.

[0022] 4. The drying room is equipped with a dehumidification vent. After the moisture in the drying room is extracted, it is cooled and condensed around the evaporator to dehydrate, thereby reducing the humidity in the drying room and improving the drying efficiency of the wood. At the same time, the waste heat of the exhaust air is fully utilized to heat the evaporator, improving the working efficiency of the heat pump drying unit and saving energy.

[0023] 5. A guide fan is installed between the evaporator and condenser installation chambers to guide the dry air dehydrated by the evaporator to the condenser for heating and then back into the drying chamber. This realizes the reuse of the dehumidified dry air, which can significantly improve drying efficiency and shorten drying time compared to directly using outdoor air with higher humidity.

[0024] 6. A dehumidification vent is installed in the middle of the drying room, which can adjust the balance of the air volume entering and leaving the drying room to achieve the best drying efficiency.

[0025] 7. A dehumidification vent is installed at the top of the drying room. By utilizing the characteristic of hot and humid air rising, the high humidity air is discharged more quickly, preventing moisture from accumulating in the upper space and speeding up the overall drying process. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the hot air circulation drying system in Embodiment 1 of this utility model.

[0027] Figure 2 This is a top view of the lower cavity of the drying chamber in Embodiment 1 of this utility model.

[0028] Figure 3 This is a schematic diagram of the partition in Embodiment 1 of this utility model.

[0029] Figure 4 This is a schematic diagram of the structure of the rear wall of the drying chamber in Embodiment 1 of this utility model.

[0030] Figure 5 This is a schematic diagram of the drying bracket in an embodiment of the present invention.

[0031] Figure 6 This is a schematic diagram of the integrated heating device in an embodiment of the present invention.

[0032] Figure 7 for Figure 6 A top view of the connection between the integrated heating equipment and the drying room.

[0033] Figure 8 This is a top view of the lower cavity of the drying chamber in Embodiment 2 of this utility model.

[0034] Figure 9 This is a schematic diagram of the partition in Embodiment 2 of this utility model.

[0035] In the diagram: 1. Drying oven; 11. Upper cavity; 12. Lower cavity; 13. Aisle; 2. Drying rack; 20. Sheet; 21. Receiving frame; 22. Support leg; 3. Heat pump dryer unit; 31. Compressor; 32. Evaporator; 33. Condenser; 34. Blower; 35. First installation chamber; 36. Second installation chamber; 37. Air guide fan; 38. Drain pipe; 4. Air duct; 5. Partition; 51. Circulation. 52. Fan; 53. Panel; 6. Return air vent; 7. Dehumidification vent; 8. Dehumidification outlet; 91. Dehumidification fan; 102. Dehumidification inlet; 103. Exhaust outlet; 104. Dehumidification inlet; 105. Dehumidification outlet. Detailed Implementation

[0036] The present invention will now be further described in conjunction with the accompanying drawings and embodiments:

[0037] In the description of this utility model, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "horizontal", and "vertical" are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, and therefore should not be construed as a limitation of this utility model. Example 1

[0038] like Figure 1 As shown, this embodiment provides a hot air circulating drying system, including a drying chamber 1, a drying support 2 installed inside the drying chamber 1, and a heat pump drying unit 3 installed outside the drying chamber 1. In this embodiment, the internal dimensions of the drying chamber 1 are 7.5 meters long from front to back, 7.5 meters long from side to side, and 5.5 meters high. This specification of the drying chamber 1, combined with the following structural design, can achieve large-scale and efficient drying operations.

[0039] The heat pump dryer unit 3 includes a compressor 31, an evaporator 32, a condenser 33, and a blower 34. Its working principle is based on the compressor 31 driving refrigerant circulation. The liquid refrigerant absorbs heat in the evaporator 32 and evaporates into a gaseous state, then releases heat in the condenser 33 and condenses back into a liquid state, repeating the cycle to achieve heat transfer. This hot air circulation drying system utilizes the heat released in the condenser 33 to heat the drying chamber 1 to dry the sheet metal 20. The evaporator 32 and condenser 33 are respectively arranged in the first installation chamber 35 and the second installation chamber 36, and the air inlet of the blower 34 is connected to the second installation chamber 36.

[0040] like Figure 2As shown, air supply ducts 4 are laid along the walls of drying chamber 1 on the floor. Air supply ducts 4 are divided into a rear section, a left section, and a right section, laid along the rear and left / right side walls of drying chamber 1. The left and right sections of air supply duct 4 extend to the front ends of the left and right side walls of drying chamber 1, respectively, with air outlets at their front ends. The left and right air outlets are 20-30cm away from the front wall of drying chamber 1. The air outlet of the blower 34 is connected to the rear section of air supply duct 4 via a pipe, used to deliver air heated by the condenser 33 into drying chamber 1 through air supply duct 4.

[0041] To compensate for the poor heating effect of the heat pump dryer unit 3 under low temperature or high load conditions, the hot air circulation drying system is equipped with an electromagnetic heating device. This device includes a heating coil 92, a temperature sensor (not shown in the figure), and an electromagnetic heater 91 connected to the heating coil 92. The duct after the air outlet of the blower 34 includes a heating pipe section 93 adjacent to the outlet. The heating coil 92 is wound around the heating pipe section 93, and the temperature sensor is installed inside the heating pipe section 93 to sense the temperature of the hot air inside the duct. When the temperature of the hot air inside the heating pipe section 93 is lower than the set temperature, the electromagnetic heater 91 and the heating coil 92 operate to assist the heat pump dryer unit 3 in heating the air supplied to the drying chamber 1. Furthermore, the heating coil 92 is wrapped with insulation cotton (not shown in the figure) to prevent heat loss, reduce energy waste, and improve heating efficiency.

[0042] like Figure 3 As shown, a partition 5 divides the drying chamber 1 into an upper cavity 11 and an upper cavity 12. At least one row of circulating fans 51, evenly spaced in a left-right direction, is installed on the partition 5. In this embodiment, the partition 5 is 4.2 meters above the ground of the drying chamber 1. The circulating fans 51 are arranged in a row, extending from one end of the partition 5 to the other in a left-right direction, and are positioned at the midpoint of the front-back direction of the drying chamber 1. The air outlets of the circulating fans 51 face vertically downwards to create a downward airflow. The partition 5 has mounting positions for the circulating fans 51, with each circulating fan 51 mounted on a corresponding mounting plate 52. The mounting plates 52 are detachably fastened to their respective mounting positions for easy maintenance and replacement. Each circulating fan 51 is equipped with an air damper (not shown in the figure) below it. The size of the air damper is sufficient to cover the installation position of the circulating fan 51. When some circulating fans 51 are not in operation, the corresponding air damper is closed, which can effectively seal the corresponding airflow channel and prevent heat loss. In addition, the baffle plate 5 is also evenly distributed with return air holes 53 for air recirculation.

[0043] like Figure 5As shown, the drying rack 2 is a vertically mounted rack for vertically placing the sheet metal 20. The drying rack 2 includes a receiving frame 21 for vertically placing the sheet metal 20 and support legs 22 connected to the receiving frame 21. The sheet metal 20 within the receiving frame 21 is placed perpendicular to the left-right direction. Specifically, the drying rack 2 can adopt the sheet metal drying rack disclosed in Chinese Patent Application Publication No. CN222027370U filed by the applicant. Figure 1 and Figure 2 As shown, several drying racks 2 are stacked vertically and horizontally to form a stack, and horizontal air ducts are formed between the upper and lower drying racks 2 and between the bottom drying rack 2 and the ground. The stacked drying racks 2 are placed in rows along the left and right direction on the ground of the upper cavity 12 of the drying room 1. Multiple rows of stacked drying racks 2 are arranged in the drying room 1, and a passage 13 is left directly below each row of circulating fans 51, thus forming the air supply channel of the circulating fans 51. In this embodiment, the dimensions of the sheet 20 are 1.32 meters × 0.66 meters, and the thickness is 1.6-1.7 millimeters. The dimensions of the drying rack 2 are 2.2 meters long × 1.5 meters wide × 1.35 meters high (excluding the supporting legs 22). Each drying rack 2 has two receiving frames 21 with dimensions of 2.1 meters long × 0.66 meters wide × 1.35 meters high. Each receiving frame 21 can hold approximately 1250 sheets of sheet 20. Every three drying racks 2 are stacked vertically to form a stack, and three stacks are placed in a row. There are two rows at the front and two rows at the back of the drying room 1, with a passageway 13 in the middle corresponding to the circulating fan 51, for a total of four rows and 36 drying racks 2. Each drying rack 2 can hold approximately 2500 sheets of sheet 20. The entire drying room 1 can dry approximately 90,000 sheets of sheet 20 at the same time, which is about 120 cubic meters, equivalent to the workload of about 4500 square meters of drying yard, greatly improving land utilization.

[0044] like Figure 1 and Figure 4 As shown, in order to reduce the humidity inside the drying chamber 1 and improve the drying efficiency of the wood, a dehumidification port 6 is provided at the lower part of the rear wall of the drying chamber 1. The dehumidification port 6 is connected to the first installation chamber 35 of the evaporator 32 through a pipe, and a dehumidifying fan 61 that drives the airflow is provided in conjunction with the dehumidification port 6. After the moisture inside the drying chamber 1 is extracted, it is cooled and condensed around the evaporator 32 to achieve the purpose of dehumidification. At the same time, the waste heat of the exhaust air is fully utilized to heat the evaporator 32, thereby improving the working efficiency of the heat pump drying unit 3. In this embodiment, the dehumidification port 6 is 0.2-0.25 meters above the ground. The dehumidifying fan 61 can be installed inside the dehumidification port 6, inside the pipe, at the outlet of the pipe, or at the air outlet of the first installation chamber 35, depending on the actual situation. A drain pipe 38 is also connected to the first installation chamber 35, and the water condensed during the dehumidification process is discharged through the drain pipe 38.

[0045] To balance the airflow in and out of the drying chamber 1, a dehumidification vent 7 connecting to the outside is provided in the middle of the rear wall of the drying chamber 1. A dehumidification fan 71 is associated with the dehumidification vent 7. By controlling the operation of the dehumidification fan 71, the net airflow can be controlled while dehumidifying, achieving optimal drying efficiency. In this embodiment, the dehumidification vent 7 is 1.2-1.3 meters above the ground.

[0046] To prevent moisture from accumulating in the upper space, at least one exhaust vent 8 connecting to the outside is provided on the upper part of the rear wall of the drying chamber 1. An exhaust fan 81 is associated with the exhaust vent 8 to accelerate the discharge of high-humidity air and speed up the overall drying process. In this embodiment, there are three exhaust vents 8. In this embodiment, the exhaust vents 8 are 5 meters above the ground.

[0047] To make full use of the dehumidified dry air, the first installation chamber 35 and the second installation chamber 36 are connected, and a guide fan 37 is provided between the two installation chambers. The guide fan 37 guides the dry air in the first installation chamber 35, which has been cooled and dehydrated by the evaporator 32, into the second installation chamber 36. After being heated by the condenser 33, it is sent back into the drying room 1. Compared with directly using outdoor air with higher humidity, this can significantly improve drying efficiency and shorten drying time.

[0048] The hot air circulating drying system is also equipped with a control system (not shown in the figure). The control system is electrically connected to the heat pump dryer unit 3, electromagnetic heater 91, temperature sensor, circulating fan 51, dehumidifying fan 61, dehumidifying fan 71, exhaust fan 81, and guide fan 37. It is used to control the intelligent and efficient operation of the entire drying system. The opening and closing of the air damper is also controlled by the control system.

[0049] In specific implementation, such as Figure 6 and Figure 7As shown, the heat pump dryer unit 3, the electromagnetic heating device, and the control system can be integrated into a single integrated heating device 100. The dehumidifying fan 61 and the dehumidifying fan 71 can also be integrated into this device. The device is equipped with a hot air outlet 101, a dehumidifying air inlet 102, a drain outlet 103, a dehumidifying air inlet 104, and a dehumidifying air outlet 105. The hot air outlet 101 is connected to the rear section of the air supply pipe 4 inside the drying chamber 1 via a pipe. The dehumidifying air inlet 102 and the drain outlet 103 are both located in the first mounting chamber 35 of the evaporator 32. The dehumidifying air inlet 102 is connected to the rear section of the air supply pipe 4 inside the drying chamber 1 via a pipe. The drying chamber 71 is connected to the dehumidification port 6 of the drying room 1. The dehumidification fan 61, like the guide fan 37, is located between the first installation chamber 35 and the second installation chamber 36. A drain pipe 38 is connected to the drain outlet 103. The dehumidification inlet 104 and dehumidification outlet 105 are connected to the inlet and outlet of the dehumidification fan 71, respectively. The dehumidification inlet 104 is connected to the dehumidification port 7 of the drying room 1 via a pipe, and the dehumidification outlet 105 is directly connected to the outside. The equipment can also be equipped with a display device and an input device (not shown in the figure) for monitoring and displaying the operating status of the drying system and inputting setting parameters. Specifically, this equipment can adopt a wood drying device disclosed in Chinese Patent Publication No. CN210801849U filed by the applicant.

[0050] The drying method of this hot air circulating drying system includes the following steps:

[0051] Step 1: Place the sheet 20 to be dried vertically in the drying rack 2, so that the sheet 20 is perpendicular to the left and right direction. Then, stack the drying racks 2 vertically and vertically, and place them in rows on the ground of the upper cavity 12 of the drying room 1. Leave an appropriate gap between each row of drying racks 2, and leave an aisle 13 directly below each row of circulating fans 51.

[0052] Step 2: The control system starts the compressor 31, blower 34, circulating fan 51 and dehumidifying fan 61. The compressor 31 delivers refrigerant to circulate between the evaporator 32 and the condenser 33. The hot air heated by the condenser 33 in the second installation chamber 36 enters the air supply pipe 4 through the pipe under the action of the blower 34.

[0053] At this time, the temperature sensor senses the temperature inside the heating tube section 93. When the hot air temperature inside the heating tube section 93 does not reach the set temperature, the control system controls the electromagnetic heater 91 to start working and heats the inside of the heating tube section 93 through the heating coil 92. When the hot air temperature inside the heating tube section 93 is higher than the set temperature, the control system controls the electromagnetic heater 91 to stop working. In this embodiment, it is necessary to make the hot air temperature inside the heating tube section 93 reach 110℃-150℃.

[0054] Hot air is sent into the drying room 1 through the air supply pipe 4 from the air outlets on both sides. The circulating fan 51 blows air downwards. The hot air diffuses through the horizontal air duct between the drying racks 2 and rises from the gaps between adjacent stacks and the gaps between the vertically placed boards 20. At the same time, it takes away the moisture in the wood and then flows back to the upper cavity 11 through the return air hole 53 on the partition 5 to form a hot air circulation and dry the boards 20.

[0055] Meanwhile, the dehumidifying fan 61 draws the hot and humid air in the drying chamber 1 to the first installation chamber 35, where it is cooled, condensed, and dehumidified by the evaporator 32. The dehumidified air is then introduced into the second installation chamber 36 by the guide fan 37, heated by the condenser 33, and then sent back into the drying chamber 1. The dehumidifying fan 71 effectively regulates the balance of the air volume entering and leaving the drying chamber 1, keeping the air volume entering greater than the air volume leaving. The exhaust fan 81 accelerates the removal of moisture from the upper space.

[0056] During the drying process, when it is necessary to pause some or all of the circulating fans 51, the control system controls the corresponding circulating fan 51 to stop running and controls the corresponding damper to close after a delay of 5-10 seconds; when it is necessary to restart the circulating fan 51, the corresponding damper is controlled to open 5-10 seconds in advance.

[0057] Step 3: The control system maintains the temperature of the drying room 1 at 40℃-50℃, and the hot air continues to circulate to remove the moisture from the skin 20 until the skin 20 reaches the set moisture content.

[0058] Step 4: After drying is completed, the control system stops the compressor 31 and all fans.

[0059] The hot air circulation drying system of this embodiment can dry approximately 90,000 sheets of 20 sheets of wood at a time, with a cycle of about 7 days. Compared with traditional drying yards, the hot air circulation drying system of this invention has significant advantages in production efficiency, low energy consumption, and significantly reduced operating costs, resulting in excellent economic benefits and environmental performance. Example 2

[0060] This embodiment has a basically the same structure as Embodiment 1, except that: Figure 8 and Figure 9 As shown, the circulating fans 51 installed on the partition 5 are in two rows, located at the front and rear of the drying chamber 1 respectively. A passageway 13 corresponding to the front circulating fans 51 is left between the frontmost drying rack 2 and the front wall of the drying chamber 1, and a passageway 13 corresponding to the rear circulating fans 51 is left between the last drying rack 2 and the rear wall of the drying chamber 1. Setting up two rows of circulating fans 51 allows for more flexible and selective control of the front and rear circulating fans 51, or the simultaneous opening and closing of both rows. This enables more precise control of the heat distribution in different areas of the drying chamber 1 according to the drying process requirements, helping to improve drying uniformity.

[0061] It is understood that those skilled in the art can make various other corresponding changes and modifications based on the technical concept of this utility model, and all such changes and modifications should fall within the protection scope of the claims of this utility model.

Claims

1. A hot air circulating drying system, comprising a drying chamber, a drying rack disposed within the drying chamber, and a heat pump drying unit disposed outside the drying chamber, wherein the heat pump drying unit comprises a compressor, an evaporator, a condenser, and a blower, characterized in that: The evaporator and condenser are respectively arranged in the first installation chamber and the second installation chamber, and the air inlet of the blower is connected to the second installation chamber; an air supply pipe is laid on the floor of the drying chamber along the wall of the drying chamber, and the air supply pipe has two air outlets located at the front ends of the left and right side walls respectively. The air outlet of the blower is connected to the air supply pipe through a pipe, which is used to send the air heated by the condenser into the drying chamber through the air supply pipe. The drying room is divided into an upper cavity and a lower cavity by a partition. At least one row of circulating fans is installed on the partition, which are arranged at equal intervals in the left and right direction. The air outlets of the circulating fans are vertically downward. The partition is also evenly distributed with return air holes. The drying rack is a vertical drying rack used to vertically place the boards. The drying racks are placed in rows along the left and right direction on the floor of the lower cavity of the drying room. It also includes a control system, which is electrically connected to the heat pump dryer unit and the circulating fan, and is used to control the operation of the heat pump dryer unit and the circulating fan.

2. The hot air circulating drying system according to claim 1, characterized in that: It also includes an electromagnetic heating device, which includes a heating coil, a temperature sensor, and an electromagnetic heater connected to the heating coil. The duct after the air outlet of the blower includes a heating pipe section located adjacent to the air outlet of the blower. The heating coil is wound around the outside of the heating pipe section, and the temperature sensor is located inside the heating pipe section. The electromagnetic heater and the temperature sensor are electrically connected to the control system. The control system controls the operation of the electromagnetic heater and the heating coil according to the temperature sensed by the temperature sensor to assist the heat pump dryer unit in heating the air sent into the drying room.

3. The hot air circulating drying system according to claim 2, characterized in that: The drying rack includes a receiving frame for vertically placing the sheet metal and supporting legs connected to the receiving frame. The sheet metal in the receiving frame is placed perpendicular to the left and right direction. Several drying racks are stacked vertically and aligned to form a stack. Horizontal air ducts are formed between the upper and lower drying racks and between the bottom drying rack and the ground. Multiple rows of stacked drying racks are arranged in the drying room, and an aisle is left directly below each row of circulating fans to form the air supply channel of the circulating fans.

4. The hot air circulating drying system according to claim 2, characterized in that: The circulating fans installed on the partition are either in a row, located in the middle of the front-to-back direction of the drying chamber; or in two rows, located at the front and rear of the drying chamber respectively.

5. The hot air circulating drying system according to claim 4, characterized in that: Each of the circulating fans is provided with a damper below it. The size of the damper is sufficient to cover the installation position of the circulating fan. The opening and closing of the damper is controlled by the control system.

6. The hot air circulating drying system according to claim 1, characterized in that: A dehumidification port is provided at the lower part of the rear wall of the drying chamber, and a dehumidification fan is provided in association with the dehumidification port. The dehumidification port is connected to the first installation chamber of the evaporator through a pipe.

7. The hot air circulating drying system according to claim 6, characterized in that: The first installation chamber is connected to the second installation chamber, and a duct fan is provided between the two installation chambers to guide the dry air cooled and dehydrated by the evaporator in the first installation chamber to the second installation chamber.

8. The hot air circulating drying system according to claim 1, characterized in that: A dehumidification vent is provided in the middle of the rear wall of the drying chamber, which connects to the outside. A dehumidification fan is installed in connection with the dehumidification vent.

9. The hot air circulating drying system according to claim 1, characterized in that: The upper part of the rear wall of the drying chamber is provided with at least one exhaust port that connects to the outside, and an exhaust fan is provided in association with the exhaust port.

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