Uniform ventilation pipeline for roller composting

Abstract

The utility model relates to the technical field of roller compost ventilation, and provides a roller compost uniform ventilation pipeline which comprises a ventilation pipe and at least one guide plate, one end of the ventilation pipe is an air inlet, and a plurality of air outlet holes communicated with the interior of the ventilation pipe are formed in the pipe wall of the ventilation pipe. The multiple air outlet holes are distributed at intervals in the length direction of the ventilation pipe, the distance between every two adjacent air outlet holes close to the air inlet is defined as the front distance, the distance between every two adjacent air outlet holes away from the air inlet is defined as the rear distance, and the rear distance is smaller than or equal to the front distance; the flow guide plates are arranged on the outer wall of the ventilation pipe, each flow guide plate is adjacent to one air outlet hole, and the flow guide plates are located on the sides, away from the air inlet, of the air outlet holes. The flow guide plate is arranged beside the air outlet hole, so that the area of a weak air area formed at the end, close to the air inlet, of the ventilation pipe is reduced. Meanwhile, the distance between the air outlet holes in the rear end of the ventilation pipe is smaller than that between the air outlet holes in the front end of the ventilation pipe, and the air outlet uniformity of the air outlet pipe is effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of drum composting ventilation, in particular to a drum composting uniform ventilation duct. Background Art

[0002] The application of drum composting in the resource utilization of livestock and poultry waste is becoming more and more widespread. In the relevant technology, ventilation directly affects the oxygen supply and is an important factor in determining the effect of aerobic fermentation composting. At present, the opening design of the drum composting ventilation duct is mostly single-row, double-row or variable-angle equidistant openings. Since the air flow in the pipe flows out through the small holes, the air flow velocity in the pipe decreases when the pipe diameter remains unchanged. At the same time, most pipe ventilation has the problem of the static pressure gradually decreasing along the air flow direction, and the small hole outflow velocity is the combined velocity of the air flow velocity in the pipe and the velocity perpendicular to the pipe wall generated by the static pressure, resulting in a large small hole outflow velocity near the air inlet and a small small hole outflow velocity at the end of the ventilation pipe. In addition, the direction of the small hole outflow airflow is determined by the static pressure and dynamic pressure. Near the air inlet, the outlet airflow will deviate from the extension direction of the pipe, resulting in a weak ventilation area in the outlet area near the air inlet end of the ventilation pipe. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems in the related art. To this end, the present invention proposes a uniform ventilation duct for drum composting, which aims to reduce the area of the weak air outlet area of the ventilation duct and improve the air outlet uniformity of the ventilation duct.

[0004] The uniform ventilation duct for drum composting according to the embodiment of the utility model comprises:

[0005] A ventilation duct, wherein one end of the ventilation duct is an air inlet, and a plurality of air outlet holes are opened on the wall of the ventilation duct, wherein the plurality of air outlet holes are arranged at intervals along the length of the ventilation duct, and the distance between two adjacent air outlet holes close to the air inlet is defined as a front distance, and the distance between two adjacent air outlet holes away from the air inlet is defined as a rear distance, and the rear distance is less than or equal to the front distance;

[0006] At least one guide plate is provided on the outer wall of the ventilation duct, one guide plate is provided adjacent to one of the air outlets, and the guide plate is located on a side of the air outlet away from the air inlet.

[0007] According to the embodiment of the utility model, the roller composting uniform ventilation duct uses one end of the ventilation duct as the air inlet to supply air into the duct. At the same time, a plurality of air outlet holes are opened on the duct wall, and the air outlet holes are arranged at intervals along the length direction of the ventilation duct to supply air to multiple areas. In addition, a guide plate is provided on the side of the air outlet hole. When the air flow in the duct is ejected from the air outlet hole, the guide plate stops the air flow in the duct at the side of the air outlet hole away from the air inlet to prevent the ejected air flow from being deflected to the side of the air outlet hole away from the air inlet, thereby reducing the area of the weak wind area formed at the end of the ventilation duct adjacent to the air inlet, and effectively improving the air outlet uniformity of the air outlet duct. At the same time, the air outlet holes on the ventilation duct are arranged gradually densely along the flow direction of the air flow to ensure the air outlet volume at the rear end, so that the ventilation volume of each composting area can be made consistent, thereby improving the uniformity of oxygen supply in each area.

[0008] According to an embodiment of the present invention, the distance between two adjacent air outlet holes decreases in the direction away from the air inlet.

[0009] According to one embodiment of the present invention, the decreasing amplitude of the distance between each two adjacent air outlet holes is in the range of 0.1*L / n~0.3*L / n, wherein L is the length of the ventilation pipe and n is the number of air outlet holes on the ventilation pipe.

[0010] According to one embodiment of the present invention, the ventilation duct includes multiple pipe sections, each of the pipe sections is provided with multiple air outlets, and the spacing between two adjacent air outlets in the same pipe section is equal. The spacing between two adjacent air outlets in the pipe section adjacent to the air inlet is defined as a first spacing, and the spacing between two adjacent air outlets in the pipe section away from the air inlet is defined as a second spacing, and the first spacing is greater than the second spacing.

[0011] According to one embodiment of the present invention, the ventilation duct has an arrangement area adjacent to one end of the air inlet, the arrangement area is used to arrange at least one guide plate, the length of the arrangement area is L1, the length of the ventilation duct is L, and L1 is less than L.

[0012] According to one embodiment of the present invention, L1 is less than or equal to L / 8.

[0013] According to an embodiment of the present invention, the diameter of the air outlet is 1 mm to 2 cm.

[0014] According to one embodiment of the present invention, the height of the guide plate is greater than the diameter of the air outlet.

[0015] According to one embodiment of the present invention, the height of the guide plate is 2 mm to 4 cm.

[0016] According to one embodiment of the present invention, the height of the guide plate is greater than or equal to twice the diameter of the air outlet.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a structural diagram of a uniform ventilation duct for drum composting provided by an embodiment of the utility model;

[0020] Figure 2 This is the airflow distribution cloud diagram inside the drum under the existing ventilation pipe with equal hole spacing and no guide plate;

[0021] Figure 3 This is a cloud diagram of the air flow distribution inside the drum of the drum composting uniform ventilation duct provided by the embodiment of the utility model with variable hole spacing and additional guide plates.

[0022] Reference numerals:

[0023] 1. Ventilation duct; 11. Air inlet; 12. Air outlet; 2. Deflector; DETAILED DESCRIPTION

[0024] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0025] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0026] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on specific circumstances.

[0027] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," or "above" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below," "below," or "below" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is lower in level than the second feature.

[0028] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0029] The application of drum composting in the resource utilization of livestock and poultry waste is becoming more and more widespread. In the relevant technology, ventilation directly affects the oxygen supply and is an important factor in determining the effect of aerobic fermentation composting. At present, the opening design of the drum composting ventilation duct is mostly single-row, double-row or variable-angle equidistant openings. Since the air flow in the pipe flows out through the small holes, the air flow velocity in the pipe decreases when the pipe diameter remains unchanged. At the same time, most pipe ventilation has the problem of the static pressure gradually decreasing along the air flow direction, and the small hole outflow velocity is the combined velocity of the air flow velocity in the pipe and the velocity perpendicular to the pipe wall generated by the static pressure, resulting in a large small hole outflow velocity near the air inlet and a small small hole outflow velocity at the end of the ventilation pipe. In addition, the direction of the small hole outflow airflow is determined by the static pressure and dynamic pressure. Near the air inlet, the outlet airflow will deviate from the extension direction of the pipe, resulting in a weak ventilation area in the outlet area near the air inlet end of the ventilation pipe. In response to the above problems, the present application proposes a uniform ventilation duct suitable for a drum, which reduces the area of the weak ventilation zone near the air inlet 11 by adding a guide plate 2 at the air outlet 12, and reduces the difference in air outlet volume before and after the ventilation duct 1 by changing the spacing between the air outlet holes 12 on the ventilation duct 1, thereby achieving uniform ventilation in the drum composting process.

[0030] like Figure 1 As shown, according to the embodiment of the present invention, the drum composting uniform ventilation duct includes a ventilation duct 1 and at least one guide plate 2, one end of the ventilation duct 1 is an air inlet 11, and the wall of the ventilation duct 1 is provided with a plurality of air outlet holes 12 in the connecting pipe, and the plurality of air outlet holes 12 are arranged at intervals along the length direction of the ventilation duct 1, and the spacing between two adjacent air outlet holes 12 close to the air inlet 11 is defined as the front spacing, and the spacing between two adjacent air outlet holes 12 away from the air inlet 11 is defined as the rear spacing, and the rear spacing is less than or equal to the front spacing. It should be noted that the front spacing and rear spacing here only refer to the position of the air outlet holes 12 relative to the air inlet 11, that is, the rear spacing can be equal to the front spacing, and the rear spacing can also be less than the front spacing; the guide plate 2 is provided on the outer wall of the ventilation duct 1, a guide plate 2 is provided adjacent to an air outlet 12, and the guide plate 2 is located on the side of the air outlet 12 away from the air inlet 11.

[0031] Optionally, one end of the ventilation pipe 1 is opened to form an air inlet 11 , and the air inlet 11 is connected to the space inside the pipe, and the other end of the ventilation pipe 1 can be closed so that the air flow in the pipe is discharged only from the air outlet 12 .

[0032] According to the embodiment of the utility model, the uniform ventilation duct for roller composting uses one end of the ventilation duct 1 as the air inlet 11 to supply air into the duct. At the same time, a plurality of air outlet holes 12 are opened in the duct wall. The air outlet holes 12 are arranged at intervals along the length of the ventilation duct 1 to supply air to multiple areas. In addition, a guide plate 2 is provided next to the air outlet hole 12. When the air flow in the duct is ejected from the air outlet hole 12, the guide plate 2 stops the air flow at the side of the air outlet hole 12 away from the air inlet 11 to prevent the ejected air flow from being deflected to the side of the air outlet hole 12 away from the air inlet 11, thereby reducing the area of the weak wind area formed at the end of the ventilation duct 1 adjacent to the air inlet 11, and effectively improving the uniformity of the air outlet of the air outlet duct. At the same time, the air outlet holes 12 on the ventilation duct 1 are arranged gradually densely along the flow direction of the air flow to ensure the air output at the rear end, so that the ventilation volume of each composting area can be consistent, thereby improving the uniformity of oxygen supply in each area.

[0033] It can be understood that since the flow rate near the air inlet 11 on the ventilation duct 1 is faster, and the air outlet 12 is located on the tube wall of the ventilation duct 1, the opening direction of the air outlet 12 is perpendicular to the extension direction of the ventilation duct 1. In this way, the wind blown into the ventilation duct 1 from the air inlet 11 will deviate in the direction away from the air inlet 11 when it is blown out from the air outlet 12 adjacent to the air inlet 11. Then, there will be a weak wind area at one end of the ventilation duct 1 adjacent to the air inlet 11 where the air outlet 12 cannot correspond to the blowing air. For this reason, a guide plate 2 is provided to stop the deviated outlet air so as to blow it toward the weak wind area, reduce the area of the weak wind area, and improve the uniformity of the air outlet.

[0034] It can be understood that, with the airflow direction in the ventilation duct 1 as the front end, that is, the end close to the air inlet 11 as the front end, the spacing of the air outlet holes 12 close to the front end is greater than or equal to the spacing of the air outlet holes 12 at the rear end, so as to ensure that the air outlet holes 12 on the ventilation duct 1 are arranged gradually densely along the flow direction of the airflow. For example, the spacing of the air outlet holes 12 arranged in the ventilation duct 1 along the flow direction of the airflow can be gradually reduced.

[0035] In other embodiments, the ventilation duct 1 can also be set as multiple sections, with multiple air outlets 12 set in each section. The air outlet holes 12 set in each section are equally spaced, and the spacing between the air outlet holes 12 on the multiple sections gradually decreases along the flow direction of the airflow.

[0036] According to one embodiment of the present invention, the ventilation duct 1 has a layout area adjacent to one end of the air inlet 11, and the layout area is used to arrange at least one deflector 2. The length of the layout area is L1, and the length of the ventilation duct 1 is L, where L1 is less than L. It can be understood that if the direction of the airflow in the ventilation duct 1 is defined as the front end, then a layout area can be set at the front end of the ventilation duct 1 for arranging the deflector 2. The number of deflectors 2 can be one, two, or more, and each deflector 2 is set corresponding to an air outlet 12. For example, a deflector 2 is set corresponding to the first air outlet 12 in the direction from the front end to the rear end of the ventilation duct 1, and thereafter, a deflector 2 can be set every other air outlet 12 or every two air outlets 12 to adjust according to the actual air outlet situation to ensure air outlet uniformity.

[0037] According to one embodiment of the present invention, L1 is less than or equal to L / 8. Since the airflow velocity at the rear end of the ventilation duct 1 is reduced, the weak wind area at the rear end is less likely to appear, and the guide plate 2 may not be provided, such as the length of the layout area is less than the length of the ventilation duct 1. In this way, the guide plate 2 is provided only in the layout area, which is conducive to cost saving. In one embodiment, only the area of the front end of the ventilation duct 1, which is one-eighth of the area, is used as the layout area, that is, the guide plate 2 is only installed for the air outlet 12 in the area of the front end of the ventilation duct 1, which can effectively reduce the area of the weak wind area and save costs. In other embodiments, the length of the layout area can be adjusted according to the different sizes of the ventilation duct 1, for example, L1 is equal to L / 9 or L / 10, etc., which is not limited here.

[0038] According to one embodiment of the present invention, the diameter of the air outlet 12 is 1 mm to 2 cm. It is understood that the diameter of the air outlet 12 is determined according to the inner diameter of the ventilation pipe 1 and the actual air outlet demand to ensure the oxygen supply effect.

[0039] According to one embodiment of the present invention, the height of the guide plate 2 is greater than the diameter of the air outlet 12 , and the guide plate 2 has a larger stopping area, so that the guide plate 2 can better stop the wind blown out from the air outlet 12 .

[0040] According to one embodiment of the present invention, the height of the guide plate 2 is 2 mm to 4 cm. For example, if the diameter of the air outlet 12 is 1 mm, the height of the guide plate 2 is 2 mm, or if the diameter of the air outlet 12 is 2 cm, the height of the guide plate 2 is 4 cm. In this way, it is ensured that the height of the guide plate 2 is greater than the diameter of the air outlet 12, and the wind blocking effect is better. It can be understood that one end of the guide plate 2 is connected to the outer wall of the ventilation duct 1, and the connection method can be bonding, welding or an integrated molding structure, which is not limited here. Among them, one end of the guide plate 2 is connected to the outer wall of the ventilation duct 1, and the other end extends perpendicular to the outer wall of the ventilation duct 1 in a direction away from the ventilation duct 1. It should be noted that the height of the guide plate 2 refers to the distance between the side of the guide plate 2 facing away from the ventilation duct 1 and the outer wall of the ventilation duct 1.

[0041] According to one embodiment of the present invention, the height of the deflector plate 2 is greater than or equal to twice the diameter of the air outlet 12. For example, if the diameter of the air outlet 12 is 1 mm, the height of the deflector plate 2 should be at least 2 mm. Alternatively, if the diameter of the air outlet 12 is 2 cm, the height of the deflector plate 2 should be at least 4 cm. This ensures that the deflector plate 2 can better guide the airflow, allowing the airflow to flow more effectively to the area near the air inlet 11 of the ventilation duct 1, thereby reducing the area of weak wind.

[0042] According to an embodiment of the present invention, the distance between two adjacent air outlet holes 12 is greater than or equal to 10 cm. In other words, the number of air outlet holes 12 on a one-meter-long ventilation pipe 1 is controlled within ten to control production costs.

[0043] According to one embodiment of the present invention, the distance between two adjacent air outlet holes 12 decreases in the direction away from the air inlet 11. It should be noted that static pressure recovery will not occur in the livestock and poultry waste composting ventilation duct 1, that is, the static pressure in the duct gradually decreases along the flow direction of the air flow, and the air outlet speed of each air outlet hole 12 gradually decreases along the flow direction of the air flow, so the distance between each air outlet hole 12 is set to decrease along the flow direction of the air flow. The air outlet holes 12 on the ventilation duct 1 are arranged gradually densely along the flow direction of the air flow to ensure the air outlet volume at the rear end. In order to make the ventilation volume of each composting area tend to be consistent, the spacing between the openings on the air duct continuously decreases from the front end to the rear end.

[0044] According to one embodiment of the present invention, the spacing between two adjacent air outlet holes 12 decreases by an amount ranging from 0.1*L / n to 0.3*L / n, where L is the length of the ventilation duct and n is the number of air outlet holes on the duct. For example, if L is 1 meter and n is 10, the decreasing amount ranges from 1 cm to 3 cm. For example, if a 1-meter ventilation duct is provided with 10 air outlet holes, the spacing between two adjacent air outlet holes 12 decreases by 1 cm, 2 cm, or 3 cm along the extension direction of the ventilation duct 1. This ensures consistent ventilation in each composting area while maintaining reasonable production costs.

[0045] According to one embodiment of the present invention, the ventilation duct 1 includes a plurality of connected pipe sections, each of which is provided with a plurality of air outlets 12. The spacing between two adjacent air outlets 12 in the same pipe section is equal. The spacing between two adjacent air outlets 12 in the pipe section adjacent to the air inlet 11 is defined as a first spacing, and the spacing between two adjacent air outlets 12 in the pipe section away from the air inlet 11 is defined as a second spacing, and the first spacing is greater than the second spacing. Considering the processing cost, if the air duct length is greater than 3m, the ventilation duct 1 illustratively includes a front pipe section, a middle pipe section, and a rear pipe section connected to each other. The front pipe section is provided with a plurality of first air outlets, and the spacing between each two adjacent first air outlets is the same to facilitate production. Similarly, the middle pipe section is provided with a plurality of second air outlets, and the spacing between each two adjacent second air outlets is the same to facilitate production. Similarly, the rear pipe section is provided with a plurality of third air outlets, and the spacing between each two adjacent third air outlets is the same to facilitate production. Thus, the distance between two adjacent first air outlet holes is the first distance, the distance between two adjacent second air outlet holes is the second distance, and the distance between two adjacent third air outlet holes is the third distance. Then, the first distance is greater than the second distance, which is greater than the third distance.

[0046] Please refer to Figure 2 and Figure 3 , an embodiment of the present application is described below:

[0047] Design of uniform ventilation duct for drum composting:

[0048] A set of uniform ventilation ducts for drum composting was designed, with the ventilation duct 1 as the treatment group: the ventilation duct 1 was 40 cm long and had eight air outlet holes 12 with a diameter of 2 mm on its surface. A 1 cm high guide plate 2 was set at the rear end of the first air outlet hole 12 adjacent to the front end of the ventilation duct 1. The spacing between adjacent air outlet holes 12 decreased by 0.75 cm along the air flow direction.

[0049] In order to explore the airflow distribution effect of the uniform ventilation duct 1, the existing ventilation duct 1 is used as the control group. The length of the ventilation duct 1, the number and diameter of the air outlet holes 12 of the control group are consistent with those of the treatment group, the spacing between adjacent air outlet holes 12 is consistent, and no guide plate 2 is added.

[0050] The ventilation uniformity improvement effects are as follows:

[0051] Computational fluid dynamics simulations were performed to examine the airflow characteristics of the two sets of ventilation ducts 1. During composting, both sets of ducts 1 employed positive pressure ventilation with an air inlet velocity of 1.25 m / s. Comparing the airflow simulation results for the two sets of ducts 1 revealed a significant improvement in airflow uniformity of 51.9% in the treatment group compared to the control group (existing ventilation ducts). The weak ventilation zone near air inlet 11 was significantly reduced, with the area of the weak ventilation zone decreasing by more than 20%.

[0052] Finally, it should be noted that the above embodiments are intended only to illustrate the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art will appreciate that various combinations, modifications, or equivalent substitutions of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and are intended to be encompassed by the claims of the present invention.

Claims

1. A drum composting uniform ventilation duct, characterized in that: include: A ventilation duct, wherein one end of the ventilation duct is an air inlet, and a plurality of air outlet holes are opened on the wall of the ventilation duct, wherein the plurality of air outlet holes are arranged at intervals along the length of the ventilation duct, and the distance between two adjacent air outlet holes close to the air inlet is defined as a front distance, and the distance between two adjacent air outlet holes away from the air inlet is defined as a rear distance, and the rear distance is less than or equal to the front distance; At least one guide plate is provided on the outer wall of the ventilation duct, one guide plate is provided adjacent to one of the air outlets, and the guide plate is located on a side of the air outlet away from the air inlet.

2. The drum composting uniform ventilation duct according to claim 1, characterized in that: In a direction away from the air inlet, the distance between each two adjacent air outlet holes decreases.

3. The drum composting uniform ventilation duct according to claim 2, characterized in that: The decreasing amplitude of the distance between each two adjacent air outlet holes is in the range of 0.1*L / n to 0.3*L / n, wherein L is the length of the ventilation pipe and n is the number of air outlet holes on the ventilation pipe.

4. The drum composting uniform ventilation duct according to claim 1, characterized in that: The ventilation duct includes multiple pipe sections, each of which is provided with multiple air outlets. The distance between two adjacent air outlets in the same pipe section is equal. The distance between two adjacent air outlets in the pipe section adjacent to the air inlet is defined as a first distance, and the distance between two adjacent air outlets in the pipe section away from the air inlet is defined as a second distance. The first distance is greater than the second distance.

5. The drum composting uniform ventilation duct according to any one of claims 1 to 4, characterized in that: The ventilation pipe has an arrangement area adjacent to one end of the air inlet, and the arrangement area is used to arrange at least one guide plate. The length of the arrangement area is L1, and the length of the ventilation pipe is L, and L1 is smaller than L.

6. The drum composting uniform ventilation duct according to claim 1, characterized in that: L1 is less than or equal to L / 8.

7. The drum composting uniform ventilation duct according to claim 1, characterized in that: The diameter of the air outlet is 1 mm to 2 cm.

8. The drum composting uniform ventilation duct according to claim 1, characterized in that: The height of the guide plate is greater than the diameter of the air outlet.

9. The drum composting uniform ventilation duct according to claim 1, characterized in that: The height of the guide plate is 2 mm to 4 cm.

10. The drum composting uniform ventilation duct according to claim 1, characterized in that: The height of the guide plate is greater than or equal to twice the diameter of the air outlet.

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