A special drying oven and drying device for medical cleanrooms

Abstract

This utility model discloses a drying oven and drying device specifically for pharmaceutical cleanrooms. It includes a main oven body with a connected drying chamber and a return air chamber. The main oven body wall has an air inlet section connecting to the drying chamber, and the top of the oven body door has a downward-blowing air curtain section. The drying device also includes a fresh air module and an exhaust air module. The fresh air module and the air inlet section are connected by an air inlet passage equipped with an air inlet control valve. The air inlet passage is equipped with an air inlet control valve. The main oven body is equipped with an internal circulating fan. The main oven body has an air outlet passage from the drying chamber to the return air chamber and a return air passage from the return air chamber to the drying chamber. The return air passage is equipped with a return air control valve. The return air chamber and the exhaust air module are connected by an exhaust air passage equipped with an exhaust air control valve. The air curtain section and the fresh air module are connected by an air curtain passage equipped with an air curtain control valve. The advantage of this utility model is that it controls the heat dissipation surface within a certain range, reducing cooling energy consumption.

Description

Technical Field

[0001] This utility model relates to the field of medical drying equipment technology, and in particular to a drying oven and drying device specifically for medical cleanrooms. Background Technology

[0002] In the pharmaceutical field, drying devices such as ovens are often used to sterilize medical instruments. For example, a medical microfiltration membrane base membrane dryer disclosed in Chinese patent document CN201120022230.X includes an oven, a stainless steel porous heat dissipation plate, a heating barrel, a thermoelectric fan, a roller device, and another roller device. The roller device and the other roller device are respectively installed on the support inside the oven and on the other support. The stainless steel porous heat dissipation plate is installed on the outside of the roller device and the other roller device. The stainless steel porous heat dissipation plate is fixed by the side walls on both sides of the box. The air inlet and air outlet of the oven are connected to a pipe and another pipe, respectively. The outlets of the two pipes are connected to the heating barrel and form a circulating air system with the oven. The air inlet of the heating barrel is connected to a hot air motor.

[0003] However, in actual operation of medical cleanrooms, the opening of the double-door drying ovens inside the instrument cleaning and storage rooms releases a large amount of hot air, triggering false alarms from the adjacent smoke detectors. Due to the small size of medical cleanrooms, this situation cannot be completely prevented regardless of where the smoke detectors are installed. To avoid this, users have removed the corresponding smoke alarm devices in actual operation, which does not comply with fire safety requirements. Furthermore, lowering the temperature of these two rooms to the calculated indoor temperature requires a large amount of cooling capacity, resulting in energy waste. Utility Model Content

[0004] This utility model provides a special drying oven and drying device for medical cleanrooms. While ensuring the functionality of the double-door drying oven, it controls the heat dissipation surface within a certain range and reduces energy consumption.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A special drying oven for pharmaceutical cleanrooms includes a main body with a connected drying chamber and a return air chamber inside. The main body wall has an air inlet connecting to the drying chamber, and the top of the oven door has a downward-blowing air curtain. By incorporating the air curtain, when the oven door is opened, the air curtain inflates to form an air curtain, preventing hot air from escaping from the oven door side into the pharmaceutical cleanroom, thus avoiding false alarms and reducing cooling capacity to prevent energy waste.

[0007] Preferably, the main body of the oven is rectangular, with the drying chamber located inside. Return air chambers are located on opposite sides of the drying chamber, and air inlets are located on the other two side walls of the drying chamber. This forms a double-door structure with return air functionality on both sides.

[0008] Preferably, the air curtain section includes a first high-efficiency filter and a corresponding first perforated plate for the first high-efficiency filter; the air inlet section is equipped with an inlet high-efficiency filter and a corresponding air supply perforated plate for supplying air into the oven body. The high-efficiency filter ensures the cleanliness of the gas constituting the air curtain in the air curtain section, ensuring the sterilization effect on medical devices.

[0009] Preferably, a medium-efficiency filter is installed inside the return air cavity. The side of the medium-efficiency filter is equipped with a second perforated plate with several through holes. The medium-efficiency filter is pull-out, allowing it to be removed from the return air cavity. The installation of the medium-efficiency filter ensures the accessibility of the return air, and the pull-out structure facilitates replacement and maintenance.

[0010] A drying device based on the aforementioned pharmaceutical cleanroom-specific drying oven includes the aforementioned pharmaceutical cleanroom-specific double-door drying oven, and further includes a fresh air module and an exhaust air module. The fresh air module and the air inlet section are connected by an air inlet passage equipped with an air inlet control valve. The air inlet passage is equipped with an air inlet control valve. The main body of the drying oven is equipped with an internal circulating fan. The main body of the drying oven has an air outlet passage from the drying chamber to the return air chamber and a return air passage from the return air chamber to the drying chamber. The return air passage is equipped with a return air control valve. The return air chamber and the exhaust air module are connected by an exhaust air passage equipped with an exhaust air control valve. The air curtain section and the fresh air module are connected by an air curtain passage equipped with an air curtain control valve.

[0011] The air inlet, outlet, return, exhaust, and air curtain passages are each equipped with corresponding control valves, allowing independent control of the opening and closing of each passage. When the air inlet, exhaust, and air curtain passages are closed, the return air passage remains open, enabling internal air circulation within the oven body for continuous drying and sterilization. Once the oven body has finished drying, the air inlet and exhaust passages open, facilitating overall heat dissipation within the oven body. The air curtain function prevents hot air from escaping from the oven door side during cooling, ensuring the functionality of the double-door oven while controlling the heat dissipation area within a limited range and reducing energy consumption.

[0012] Preferably, when the main body of the oven is operating, the return air control valve is open, while the air curtain control valve, fresh air control valve, and exhaust air control valve are closed. The internal circulating fan operates to circulate airflow between the drying chamber and the return air chamber. This achieves the drying and sterilization of medical instruments inside the main body of the oven with low energy consumption.

[0013] Preferably, before the main oven stops operating and the oven door is opened, the return air control valve, air curtain control valve, fresh air control valve, and exhaust air control valve are all opened, and the internal circulating fan, fresh air module, and exhaust air module operate to reduce the overall temperature inside the oven. The air curtain section forms an air curtain, which, together with the internal circulating fan, achieves overall heat dissipation inside the oven.

[0014] Preferably, when the oven door is opened, the return air control valve and internal circulation fan are closed, while the fresh air module, exhaust air module, air curtain control valve, fresh air control valve, and exhaust air control valve are opened. The air curtain forms an air curtain at the oven door to prevent high-temperature gas from escaping from the oven. The return air passage is closed, and the fresh air flow from the drying chamber through the return air chamber flows directly out from the exhaust fan, achieving unidirectional rapid heat dissipation within the oven.

[0015] Preferably, the fresh air module includes a fresh air unit and corresponding primary and secondary filters at the fresh air unit's outlet, while the exhaust module includes an exhaust fan. The fresh air unit, in conjunction with the primary and secondary filters, provides a relatively clean airflow, and the exhaust fan, in conjunction with the fresh air unit, enables unidirectional airflow within the drying chamber.

[0016] Preferably, the return air control valve, air curtain control valve, fresh air control valve, and exhaust air control valve are all electrically controlled butterfly valves. This facilitates the opening and closing of the return air passage, air curtain passage, fresh air passage, and exhaust air passage via electrical control.

[0017] The advantages of this utility model are:

[0018] 1. Ensure the drying and sterilization functions of the double-door oven;

[0019] 2. Control the heat dissipation surface within a certain range to achieve rapid heat dissipation inside the oven;

[0020] 3. Reduce energy consumption.

[0021] The beneficial effects of the above solution will be described in detail with reference to the accompanying drawings and the following embodiments. Attached Figure Description

[0022] Figure 1 This is a top view of a double-door drying oven for medical cleanrooms, as proposed in one embodiment of this utility model.

[0023] Figure 2 This is a drying device based on a double-door drying oven specifically for medical cleanrooms, as proposed in another embodiment of this utility model.

[0024] In the diagram: 1. Oven body; 2. Outer casing; 3. Drying chamber; 5. Air inlet; 6. High-efficiency air filter; 7. Air curtain; 8. First high-efficiency filter; 9. Return air chamber; 10. Medium-efficiency filter; 11. Air inlet passage; 12. Return air passage; 13. Exhaust air passage; 14. Air curtain passage; 15. Return air control valve; 16. Air curtain control valve; 17. Fresh air control valve; 18. Exhaust air control valve; 19. Fresh air unit; 20. Primary and secondary filters; 21. Exhaust fan. Detailed Implementation

[0025] Example 1,

[0026] like Figure 1 and Figure 2 As shown, one embodiment of this utility model discloses a special drying oven for medical cleanrooms, comprising an oven body 1, a drying chamber 3 and a return air chamber 9 connected within the oven body 1, an air inlet 5 communicating with the drying chamber 3 on the wall of the oven body 1, and a downward-blowing air curtain 7 at the top of the door of the oven body 1. The oven body 1 includes an outer casing 2, a heating assembly, and an internal circulation fan. The drying chamber 3 and the return air chamber 9 are disposed within the outer casing 2. When the oven body 1 is in use for drying, medical instruments are placed in the drying chamber 3, and the internal circulation fan and heating assembly are activated, forming a high-temperature airflow within the drying chamber 3. The high-temperature airflow achieves drying and sterilization of the surface of the medical instruments.

[0027] The air curtain section 7 forms a downward air curtain at the opening of the oven body 1. When the air curtain section 7 forms the air curtain, the high-temperature airflow inside the oven body 1 is difficult to escape from the drying chamber, thereby preventing false alarms from the smoke alarm device in the medical cleanroom and meeting the fire safety regulations for installing smoke alarms in medical cleanrooms. At the same time, it prevents heat from escaping into the medical cleanroom, facilitates heat dissipation inside the oven, reduces the required cooling capacity, and thus avoids energy waste.

[0028] Example 2,

[0029] like Figure 1 and Figure 2As shown, one embodiment of this utility model discloses a special drying oven for medical cleanrooms, comprising an oven body 1, a drying chamber 3 and a return air chamber 9 connected within the oven body 1, an air inlet 5 communicating with the drying chamber 3 on the wall of the oven body 1, and a downward-blowing air curtain 7 at the top of the opening of the oven body 1. The oven body 1 includes an outer casing 2, a heating assembly, and an internal circulation fan. The drying chamber 3 and the return air chamber 9 are disposed within the outer casing 2. When the oven body 1 is in drying function, medical instruments are placed in the drying chamber 3, and the internal circulation fan and heating assembly are activated, forming a high-temperature airflow within the drying chamber 3. This high-temperature airflow achieves drying and sterilization of the surface of the medical instruments. The air curtain 7 forms a downward-blowing air curtain at the opening of the oven body 1. The air curtain 7 includes a first high-efficiency filter 8 and a first perforated plate corresponding to the first high-efficiency filter 8. The first high-efficiency filter 8 ensures the cleanliness of the gas constituting the air curtain of the air curtain 7, ensuring the sterilization effect on the medical instruments.

[0030] In such Figure 1 In the double-door oven shown, the main body 1 is rectangular in shape, and the drying chamber 3 is located inside the main body 1. Return air chambers 9 are located on opposite sides of the drying chamber 3. A medium-efficiency filter 10 is installed inside each return air chamber 9. The medium-efficiency filter 10 has a second perforated plate with several through holes on its side. The medium-efficiency filter 10 is a pull-out type, allowing it to be removed from the return air chamber 9. The design of the medium-efficiency filter 10 ensures the accessibility of the return air, and its pull-out structure facilitates replacement and maintenance.

[0031] The air inlet 5 is located on the other two side walls of the drying chamber 3. The air inlet 5 is equipped with an air inlet high-efficiency filter 6 and an air supply plate that supplies air into the oven body 1 according to the corresponding air inlet high-efficiency filter 6. It forms a double-door structure and has a return air function on both sides.

[0032] In existing technology, taking a commonly used electrically heated double-door drying oven in pharmaceutical cleanrooms as an example, the original external dimensions are 2100x1350x2300mm (H), and the actual chamber dimensions are 1000x1000x1200mm (H). The chamber and outer surface are made of 304 stainless steel conforming to GMP requirements. The maximum circulating air volume is 3800m³ / h, the maximum supplementary air volume is 500m³ / h, and the heating power is 22kW. The working principle is as follows: Under the action of an internal circulating fan, dry hot air enters the chamber through a high-efficiency filter. The dry air absorbs moisture from the surface of the bottles, enters the heating channel, evaporates, and is discharged. The dry air continues to circulate in a directional manner, and water vapor is discharged, achieving the purpose of drying and sterilization. After drying, the air supply program is activated, and the bottles are removed once the requirements are met. In actual operation, when the oven door is opened after drying, a smoke alarm still occurs.

[0033] This application, through the setting of the air curtain 7 and the adjustment of the airflow passage within the oven body 1, can effectively avoid the problem of false smoke alarms.

[0034] To ensure the cleanliness of the drying airflow, as an example of a filter configuration in this invention, high-efficiency filters H14, 600mm wide and the same length as the outer casing 2, are integrated on both sides of the outer casing 2. These filters are also fitted with 304 stainless steel perforated plates with an opening ratio of at least 17%. A pull-out medium-efficiency filter 10F6, with a width and height equal to the inner cavity dimensions, is integrated into the return air cavity 9. This filter is also fitted with a 304 stainless steel perforated plate with an opening ratio of at least 25%.

[0035] Example 3,

[0036] A drying device based on the aforementioned pharmaceutical cleanroom-specific drying oven, such as... Figure 2 As shown, the oven includes the aforementioned medical cleanroom-specific drying oven, as well as a fresh air module and an exhaust air module. The fresh air module and the air inlet 5 are connected by an air inlet passage 11 equipped with an air inlet control valve. The air inlet passage 11 is equipped with an air inlet control valve. The oven body 1 is equipped with an internal circulating fan. The oven body 1 has an air outlet passage from the drying chamber 3 to the return air chamber 9 and a return air passage 12 from the return air chamber 9 to the drying chamber 3. The return air passage 12 is equipped with a return air control valve 15. The return air chamber 9 and the exhaust air module are connected by an exhaust air passage 13 equipped with an exhaust air control valve 18. The air curtain 7 and the fresh air module are connected by an air curtain passage 14 with an air curtain control valve 16.

[0037] When the drying device is in normal working condition, the medical instruments to be sterilized are placed in the drying chamber 3 of the main body 1 of the drying oven. The main body 1 of the drying oven is running, the air inlet passage 11, the air curtain passage 14 and the exhaust passage 13 are disconnected, and the return air control valve 15 of the return air passage 12 is opened to unblock the return air passage 12. The drying oven enters the internal circulation heating and sterilization mode.

[0038] After sterilization, the fresh air control valve 17, the air curtain control valve 16, and the exhaust control valve 18 are opened. The fresh air fan 19 and the exhaust fan 21, along with their corresponding electric valves, are also opened, and the fans operate at variable frequency. Once the temperature has cooled to a certain level, the return air control valve 15 is closed, all other electric airtight butterfly valves are opened, the oven door is opened, and the oven is run until the temperature drops below 40 degrees Celsius. Finally, all electric valves and equipment are closed.

[0039] When the air inlet passage 11, exhaust passage 13, and air curtain passage 14 are closed, the return air passage 12 remains unobstructed, enabling internal airflow circulation within the oven body 1 for continuous drying and sterilization. When the oven body 1 has finished drying, the air inlet passage 11 and exhaust passage 13 open, allowing for overall heat dissipation within the oven body 1. The air curtain 7 prevents hot air from escaping from the door side of the oven body 1 during cooling, thus controlling the heat dissipation surface within a certain range while ensuring the functionality of the double-door oven.

[0040] The high-efficiency filter integrated at the top of the oven door supplies air to the oven entrance and works in conjunction with the internal exhaust air. When the oven door is open, it isolates the hot air from the indoor environment, ensuring that the original indoor environment is unaffected by the hot air inside the oven, and preventing smoke detectors from triggering alarms due to high temperatures. Simultaneously, it utilizes fresh outdoor air to cool the oven, eliminating the need for the original factory's air conditioning equipment and reducing its energy consumption.

[0041] Example 4,

[0042] A drying device based on the aforementioned pharmaceutical cleanroom-specific drying oven, such as... Figure 1 and Figure 2 As shown, the oven includes the aforementioned medical cleanroom-specific drying oven, as well as a fresh air module and an exhaust air module. The fresh air module and the air inlet 5 are connected by an air inlet passage 11 equipped with an air inlet control valve. The air inlet passage 11 is equipped with an air inlet control valve. The oven body 1 is equipped with an internal circulating fan. The oven body 1 has an air outlet passage from the drying chamber 3 to the return air chamber 9 and a return air passage 12 from the return air chamber 9 to the drying chamber 3. The return air passage 12 is equipped with a return air control valve 15. The return air chamber 9 and the exhaust air module are connected by an exhaust air passage 13 equipped with an exhaust air control valve 18. The air curtain 7 and the fresh air module are connected by an air curtain passage 14 with an air curtain control valve 16.

[0043] The drying device disclosed in this embodiment utilizes the double-door drying oven disclosed in Embodiment 1, which includes an oven body 1. The oven body 1 contains a connected drying chamber 3 and a return air chamber 9. The oven body includes an outer casing 2, a heating assembly, a temperature measuring device, and an internal circulation fan. The drying chamber 3 and the return air chamber 9 are located inside the outer casing 2. When the oven body 1 is functioning as a drying device, medical instruments are placed in the drying chamber 3. The internal circulation fan and heating assembly are activated, creating a high-temperature airflow within the drying chamber 3. This high-temperature airflow achieves the drying and sterilization of the medical instruments' surfaces. An air curtain 7 forms a downward-facing air curtain at the opening of the oven body 1. The air curtain 7 includes a first high-efficiency filter 8 and a corresponding first perforated plate. The first high-efficiency filter 8 ensures the cleanliness of the airflow within the air curtain 7, guaranteeing the sterilization effect on the medical instruments.

[0044] The main body 1 of the drying oven is rectangular in shape. The drying chamber 3 is located inside the main body 1. Return air chambers 9 are located on opposite sides of the drying chamber 3. The adjacent side walls of the return air chambers 9 and the drying chamber 3 are perforated to form an air outlet passage. The drying chamber 3 and the return air chambers 9 are connected by an external pipe to form a return air passage 12. A medium-efficiency filter 10 is installed inside the return air chamber 9. The side of the medium-efficiency filter 10 is equipped with a second perforated plate with several through holes. The medium-efficiency filter 10 is a pull-out type, allowing it to be removed from the return air chamber 9. A return air control valve 15 is installed at the top air outlet of the medium-efficiency filter 10. The medium-efficiency filter 10 ensures the cleanliness of the return air, and its pull-out design facilitates replacement and maintenance. Since there are two return air chambers 9, the return air passage 12 has two branches, each connected to an exhaust passage 13. The two return air passages 12 and the exhaust passage 13 are arranged in parallel.

[0045] The main body 1 of the drying oven has an air inlet 5 that connects to the drying chamber 3. The air inlet 5 is located on the other two side walls of the drying chamber 3. The air inlet 5 is equipped with an inlet high-efficiency filter 6 and an air supply plate that supplies air into the main body 1 through the corresponding inlet high-efficiency filter 6. The top air inlet of the inlet high-efficiency filter 6 is equipped with an air inlet control valve. This forms a double-door structure with return air function on both sides. Corresponding to the air inlets 5 on both sides, the air inlet passage 11 has two parallel sets.

[0046] The top of the door of the main body of the drying oven 1 is equipped with a downward-blowing air curtain 7. When the main body of the drying oven is used in a medical clean room, when the air curtain 7 forms an air curtain, the high-temperature airflow inside the main body of the drying oven 1 is difficult to escape from the drying chamber, thereby preventing false alarms from the smoke alarm device in the medical clean room and meeting the fire protection regulations for installing smoke alarms in medical clean rooms.

[0047] The air inlet passage 11, air outlet passage, return air passage 12, exhaust air passage 13, and air curtain passage 14 are each equipped with a corresponding control valve, so that the opening and closing of each passage can be controlled independently. For ease of control, the return air control valve 15, air curtain control valve 16, fresh air control valve 17, and exhaust air control valve 18 are all electrically controlled butterfly valves.

[0048] When the main body of the oven 1 is working, the return air control valve 15 is open, while the air curtain control valve 16, the fresh air control valve 17, and the exhaust air control valve 18 are closed. The internal circulating fan operates to circulate airflow between the drying chamber 3 and the return air chamber 9. This achieves the drying and sterilization of medical instruments inside the main body of the oven 1 with low energy consumption.

[0049] Before the oven body 1 stops operating and its door is opened, the return air control valve 15, the air curtain control valve 16, the fresh air control valve 17, and the exhaust air control valve 18 are all opened. The internal circulating fan, the fresh air module, and the exhaust air module operate to reduce the overall temperature inside the oven body 1. The air curtain section 7 forms an air curtain, which, together with the internal circulating fan, achieves overall heat dissipation inside the oven.

[0050] When the overall temperature inside the oven is below 40 degrees Celsius, when the door of the oven body 1 is opened, the return air control valve 15 and the internal circulating fan are closed, while the fresh air module, exhaust air module, air curtain control valve 16, fresh air control valve 17, and exhaust air control valve 18 are opened. The air curtain 7 forms an air curtain at the door of the oven body 1 to prevent high-temperature gas from escaping from the oven body 1. The return air passage 12 is closed, and the fresh air flow from the drying chamber 3 through the return air chamber 9 flows directly out from the exhaust fan 21, achieving unidirectional rapid heat dissipation inside the oven body 1. The fresh air module includes a fresh air fan 19 and a primary and secondary efficiency filter 20 corresponding to the outlet of the fresh air fan 19, and the exhaust air module includes an exhaust fan 21. The fresh air fan 19, in conjunction with the primary and secondary efficiency filter 20, provides a relatively clean fresh air flow, and the exhaust fan 21, in conjunction with the fresh air fan 19, achieves unidirectional flow of gas inside the drying chamber. This allows the drying unit to utilize the lower temperature of the outside air for cooling, eliminating the need for air conditioning in the cleanroom and reducing other energy consumption, thus reducing cooling energy consumption.

Claims

1. A special drying oven for pharmaceutical cleanrooms, characterized in that, It includes a main body of the oven, which contains a connected drying chamber and a return air chamber. The main body of the oven has an air inlet that connects to the drying chamber, and the top of the door of the main body of the oven has a downward blowing air curtain. The drying chamber is located inside the main body of the oven. The drying chamber has return air chambers on opposite sides. The air inlet is located on the other two side walls of the drying chamber. The air curtain includes a first high-efficiency filter and a first perforated plate corresponding to the first high-efficiency filter. The air inlet is equipped with an air inlet high-efficiency filter and an air supply perforated plate corresponding to the air inlet high-efficiency filter to supply air into the main body of the oven.

2. The drying oven for pharmaceutical cleanrooms according to claim 1, characterized in that, The main body of the oven is rectangular.

3. The drying oven for pharmaceutical cleanrooms according to claim 1, characterized in that, The return air cavity is equipped with a medium-efficiency filter, and the side of the medium-efficiency filter is equipped with a second perforated plate with several through holes. The medium-efficiency filter is a pull-out type so that it can be pulled out from the return air cavity.

4. A drying apparatus based on the pharmaceutical cleanroom drying oven according to any one of claims 1 to 3, characterized in that, The aforementioned pharmaceutical cleanroom-specific drying oven also includes a fresh air module and an exhaust air module. The fresh air module and the air inlet section are connected by an air inlet passage equipped with an air inlet control valve. The air inlet passage is equipped with an air inlet control valve. The main body of the drying oven is equipped with an internal circulating fan. The main body of the drying oven has an air outlet passage from the drying chamber to the return air chamber and a return air passage from the return air chamber to the drying chamber. The return air passage is equipped with a return air control valve. The return air chamber and the exhaust air module are connected by an exhaust air passage equipped with an exhaust air control valve. The air curtain section and the fresh air module are connected by an air curtain passage with an air curtain control valve.

5. The drying apparatus according to claim 4, characterized in that, When the main body of the oven is working, the return air control valve is open, and the air curtain control valve, fresh air control valve and exhaust air control valve are closed. The internal circulating fan works to circulate the airflow in the drying chamber and the return air chamber.

6. The drying apparatus according to claim 4, characterized in that, Before the main body of the oven stops working and the oven door is opened, the return air control valve, air curtain control valve, fresh air control valve and exhaust air control valve are all opened, and the internal circulating fan, fresh air module and exhaust air module work to reduce the overall temperature inside the oven body.

7. The drying apparatus according to claim 4, characterized in that, When the oven body door is opened, the return air control valve and the internal circulation fan are closed, while the fresh air module, exhaust air module, air curtain control valve, fresh air control valve, and exhaust air control valve are opened. The air curtain section forms an air curtain at the oven body door to prevent high-temperature gas from escaping from the oven body.

8. The drying apparatus according to claim 4, characterized in that, The fresh air module includes a fresh air unit and a primary and medium-efficiency filter corresponding to the fresh air unit's air outlet, and the exhaust module includes an exhaust fan.

9. The drying apparatus according to claim 4, characterized in that, The return air control valve, air curtain control valve, fresh air control valve, and exhaust air control valve are all electrically controlled butterfly valves.

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