Dry cleaning of agricultural film roll screen and waste agricultural film dry cleaning method, device and method for separating waste agricultural film from straw

Abstract

The present disclosure relates to a dry cleaning agricultural film drum screen and a method for dry cleaning waste agricultural film, a device and a method for separating waste agricultural film from straw. The dry cleaning agricultural film drum screen comprises a drum screen and a protective cover, a central stirring rod is arranged axially in the drum screen, the top of the drum screen is provided with a feeding hopper, and the bottom is provided with a discharging bin; the protective cover encloses the drum screen and is provided with an air inlet and an air extraction dust removal port. The device for separating waste agricultural film from straw comprises crushing equipment, screening and air separation equipment, and fine separation equipment. The device and the method can effectively separate waste agricultural film, straw and sand, and the content of agricultural film fragments in the discharging material obtained after separating and processing the mixture of sand, straw and waste agricultural film is greater than 93.0wt%, and the content of sand is less than 5.0wt%.

Description

Technical Field

[0001] This invention relates to a separation device and method, and more specifically, to a screening device and separation method for separating waste plastic film and other impurities. Background Technology

[0002] Plastic mulch, as a ground cover material, can increase soil temperature, retain moisture, prevent pests and microorganisms, and promote healthy crop growth. However, the large-scale use of plastic mulch has also brought about the challenge of recycling and disposing of waste plastic mulch. Waste plastic mulch residue left in the soil can severely damage soil structure, affecting soil aeration and permeability. Although mechanized recycling technology can help clean up waste plastic mulch in farmland, the recycled mulch often contains a large amount of straw, making it difficult to reuse directly. Therefore, it is necessary to separate waste plastic mulch from impurities. The sorted waste plastic mulch can be recycled, and the straw can be used as livestock feed, thus achieving resource utilization of waste.

[0003] Discarded plastic film has a large surface area, making it prone to accumulating dust and dirt. Incomplete cleaning hinders further processing and utilization. Currently, the common method for recycling discarded plastic film is washing with water to remove surface dust and impurities. While this method cleans the film, it wastes water resources and causes environmental pollution. Especially in water-scarce provinces like Xinjiang and Gansu, washing exacerbates local water shortages. In contrast, dry cleaning, due to its water-saving and environmentally friendly characteristics, is particularly important.

[0004] CN 219381218 U discloses a rotary drum screen for recycling waste agricultural film, used for separating waste agricultural film. Its inner surface is connected to spiral-shaped baffles, the inner edges of which are serrated. The baffles and levers work together to disperse and move the waste agricultural film towards the outlet. During the screening process, soil and impurities are screened out through gradually enlarging mesh. A dust cover is fitted on the outside of the rotary drum screen to prevent dust from flying. The screened impurities are transported to a collection hopper by a conveyor mechanism for effective collection. The design of the spiral baffles and levers efficiently disperses and screens the waste agricultural film, improving screening efficiency.

[0005] Traditional water-washing methods for recycling waste plastic film not only consume large amounts of water resources but may also generate a large amount of wastewater, causing environmental pollution. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a dry-cleaning agricultural film drum screen and a method for dry-cleaning waste agricultural film, as well as a separation device and method for separating waste agricultural film and straw. This enables effective separation of waste agricultural film and straw, and dry-cleaning and dust removal.

[0007] In a first aspect, the present invention provides a dry cleaning agricultural film drum screen, comprising:

[0008] A drum screen has a screen cylinder mounted on a support. The angle between the central axis of the screen cylinder and the horizontal plane is 5-30 degrees. A central stirring rod is provided along the axial direction inside the screen cylinder. A feed hopper is provided at the top of the screen cylinder, and a discharge bin is provided at the bottom. The screen cylinder and the stirring rod are driven to rotate by a motor.

[0009] The protective cover encloses the drum screen and has multiple air inlets and at least one dust extraction port. The feed hopper and discharge bin of the drum screen extend out of the protective cover and are provided with openable and closable openings.

[0010] Secondly, the present invention provides a dry cleaning method for a mixture of waste agricultural film, using the dry cleaning device for a mixture of waste agricultural film described in the first aspect. The shredded agricultural film material enters the drum screen through the feed hopper, compressed air is introduced into the protective cover and enters the drum screen cylinder, the motor drives the drum screen to rotate, and the waste agricultural film fragments are removed from the dust under the continuous impact of the central stirring rod and the impact of the compressed air, resulting in clean shredded agricultural film; the dust blown out through the exhaust dust removal port is then subjected to subsequent processing.

[0011] Thirdly, the present invention provides a device for separating waste agricultural film and straw, comprising:

[0012] Crushing equipment is used to crush waste agricultural film mixture into small-sized film fragments.

[0013] The screening and air-separation equipment, located below the outlet of the crushing equipment, consists of a multi-layer vibrating screen, a discharge conveyor belt, and a multi-stage exhaust fan. The screen openings of the multi-layer vibrating screen, arranged vertically, are progressively smaller. A discharge conveyor belt is located below the tail of the vibrating screen, and a sand bin is located at the bottom of the multi-layer vibrating screen. The inlets of the multi-stage exhaust fan are arranged sequentially above the multi-layer vibrating screen and the discharge conveyor belt. The screening and air-separation equipment is used to screen the mixture of broken film from the crushing equipment and to remove agricultural film fragments from each stage of the vibrating screen through negative pressure.

[0014] The fine separation equipment consists of at least one dry-cleaning agricultural film drum screen as described in the first aspect, used to further dry-clean and remove dust from agricultural film fragments containing dirt.

[0015] Fourthly, the present invention provides a method for separating waste agricultural film and straw, using the aforementioned waste agricultural film and straw separation device, comprising the following steps:

[0016] S1. Waste plastic film mixed raw material enters the crushing equipment through the material inlet. The motor drives the rotary cutter to rotate at high speed, crushing the waste plastic film mixed raw material into film fragments with a size of 5-20cm, which are then discharged through the outlet.

[0017] S2. The crushed film material discharged from the crushing equipment falls onto the first-stage vibrating screen of the screening equipment. After screening, it falls onto the next stage vibrating screen in sequence. The negative pressure of the exhaust fan above each stage vibrating screen is used to suck away the film fragments. The cotton straw is put into the discharge conveyor belt at the tail of the vibrating screen, and the sand falls into the sand bin at the bottom.

[0018] S3. The agricultural film fragments collected by the air separation equipment are gathered and fed into the drum screen of the fine separation equipment. After entering the drum screen through the feed hopper, the waste agricultural film fragments are subjected to continuous impact from the central stirring bar and compressed air, causing the dust on the waste film fragments to fall off and be pushed out of the screen cylinder by the wind. The exhaust fan extracts the blown-out dust through the dust removal port for further dust removal equipment processing. Finally, the cleaned waste agricultural film is discharged from the discharge hopper.

[0019] The beneficial effects of the dry cleaning agricultural film drum screen and waste agricultural film dry cleaning method provided by this invention are as follows:

[0020] The waste agricultural film fragment dry cleaning device provided by this invention has high separation efficiency. Inside the drum of the rotary screen, the dust adhering to the agricultural film fragments is removed by the impact of the stirring rod and the collision of high-speed compressed air. The blown-out dust is discharged through the dust removal port for further processing. The dust-removed agricultural film fragments are discharged through the discharge bin of the rotary screen.

[0021] The beneficial effects of the separation device and application method for waste agricultural film and straw provided by this invention are as follows:

[0022] By integrating multiple processes such as crushing, screening, air separation, and fine separation, the effective separation of waste agricultural film and straw is achieved. The crushing equipment breaks the mixture into small-sized film fragments; the screening and air separation equipment utilizes multi-layer vibrating screens and multi-stage exhaust fans to effectively separate agricultural film fragments, straw, and sand based on the size and weight of the material particles; the fine separation equipment further dry-washes and removes dust from the agricultural film fragments containing dirt, ensuring the purity of the waste agricultural film. The waste agricultural film mixture contains more than 50 wt% sand and more than 30 wt% straw; the processed agricultural film output contains 93.0-98.0 wt% agricultural film fragments and 2.0-5.8 wt% sand. The sand removal rate can reach over 98.8%. Attached Figure Description

[0023] Figure 1 This is a front view of a dry cleaning agricultural film drum screen.

[0024] Figure 2 This is a top view of a dry cleaning device for waste agricultural film fragments.

[0025] Figure 3 This is a schematic diagram of a waste agricultural film and straw separation device.

[0026] Figure 4 This is a diagram showing the distribution of the first layer of vibrating screen and the air inlet of the exhaust fan.

[0027] Figure 5 This is a diagram showing the distribution of the second-layer vibrating screen and the air inlet of the exhaust fan.

[0028] Figure 6 This is a schematic diagram of the crushing equipment.

[0029] Figure label:

[0030] 1-Feed hopper 2-Screen cylinder 3-Central stirring rod

[0031] 4-Frame 5-Guard 6-Discharge bin

[0032] 7-First group of air inlets 8-Second group of air inlets 9-Third group of air inlets

[0033] 10-Exhaust and dust removal port

[0034] 11-Feed inlet 12-Crushing device 13-First vibrating screen

[0035] 14-Second-stage vibrating screen 15-First-stage exhaust fan 16-Second-stage exhaust fan

[0036] 17 - Stage 3 exhaust fan 18 - Stage 4 exhaust fan 19 - Stage 5 exhaust fan

[0037] 20 - Stage 6 exhaust fan; 21 - Stage 7 exhaust fan; 22 - Discharge conveyor belt

[0038] 23-Sand bin 24-Straw collection bin 25-Motor

[0039] 26 - First layer vibrating screen apertures 27 - Second layer vibrating screen apertures

[0040] 31-Crushing equipment shell; 32-Rotary cutter; 33-Feed inlet

[0041] 34-Discharge port 35-Screen plate Detailed Implementation

[0042] The specific embodiments of the present invention will be described in detail below.

[0043] In this application, directional terms such as "upper part," "lower part," "top," "bottom," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used merely for the convenience of describing the invention and should not be construed as limiting the invention.

[0044] In a first aspect, the present invention provides a dry cleaning agricultural film drum screen, comprising:

[0045] A drum screen has a screen cylinder mounted on a support. The central axis of the screen cylinder forms an angle of 5-30 degrees with the horizontal plane. A central stirring rod is provided along the axial direction inside the screen cylinder. A feed hopper is provided at the top of the screen cylinder, and a discharge bin is provided at the bottom. The screen cylinder and the stirring rod are driven to rotate by a motor.

[0046] The protective cover encloses the drum screen and has multiple air inlets and at least one dust extraction port. The feed hopper and discharge bin of the drum screen extend out of the protective cover and are provided with openable and closable openings.

[0047] In this invention, the screen cylinder is a cylindrical screen. Optionally, the screen has 5-10mm screen holes. Preferably, the screen is woven from steel wire and the screen holes are square.

[0048] Optionally, the central stirring rod consists of a main rod and multiple support rods. The support rods can be of various shapes, and the present invention is not limited in this regard. Preferably, multiple support rods are arranged in a spiral pattern on the main rod. During application, rotating the central stirring rod causes the support rods to strike the waste agricultural film fragments, dislodging the dust adhering to them. The rotational speed of the central stirring rod is 100-1200 rpm.

[0049] Optionally, the protective cover is cylindrical or rectangular, with three sets of air inlets distributed on the upper part and three sides of the protective cover, each set having 2-8 air inlets, preferably evenly distributed in a linear pattern.

[0050] Preferably, the exhaust dust removal port is connected to a dust removal device, which is selected from a bag filter or a cyclone dust collector.

[0051] In this invention, the screen cylinder is inclinedly supported on rollers fixed to the frame. Driven by the rotation of the rollers, the drum screen rotates around the axial center at a speed of 1–20 r / min.

[0052] In this invention, the screen cylinder has a feed hopper at the top and a discharge hopper at the bottom. During application, material is fed in through the feed hopper in one go. After the feed hopper is closed, the drum screen is started, while the discharge hopper remains closed to prevent material from overflowing during screening. After screening is complete, the drum screen is stopped, and the discharge hopper is opened to discharge the material. By controlling the residence time of the material in the drum screen, the dry cleaning effect is ensured.

[0053] In one embodiment, the protective cover has three sets of air inlets on the top and sides, each set including four air inlets. Four dust extraction ports are located on both sides of the bottom of the protective cover. After the drum screen is turned on, compressed air is activated, and the high-speed airflow impacts the waste agricultural film fragments, causing dust to fall off the surface of the fragments; the dust is then blown out of the drum screen and discharged through the dust extraction ports for further processing. The air velocity at the three sets of compressed air inlets is controlled between 5-15 m / s.

[0054] Optionally, the exhaust dust outlet is connected to an external exhaust fan and dust removal equipment to ensure that the internal environment of the enclosure maintains a low dust concentration.

[0055] Secondly, a dry cleaning method for a mixture of waste agricultural film is provided, using the dry cleaning device for the mixture of waste agricultural film described in the first aspect. The waste agricultural film material enters the drum screen through the feed hopper, compressed air is introduced into the protective cover and enters the drum screen cylinder, the motor drives the drum screen to rotate, and the waste agricultural film material is de-dusted under the continuous impact of the central stirring bar and the impact of compressed air, resulting in clean broken agricultural film; the dust blown out through the exhaust dust removal port is further processed.

[0056] In one specific implementation, the method includes: (1) waste agricultural film material enters the drum screen through the feed hopper, the motors of the drum screen, the central stirring rod, and the external exhaust fan are started, and each air inlet is opened to allow compressed air to enter the drum screen cylinder; (2) under the continuous impact of the central stirring rod and the impact of the compressed air, the dust attached to the waste agricultural film material falls off and is pushed to the outside of the drum by the wind. The blown dust is extracted by the external exhaust fan through the exhaust dust removal port for subsequent processing; (3) after the operation is completed, the compressed air is stopped first, the motors of the drum screen, the central stirring rod, and the external exhaust fan are turned off, and then the discharge hopper is opened to discharge the cleaned waste agricultural film.

[0057] In the dry cleaning method of this invention, the central stirring rod rotates at 100-1200 rpm, preferably 200-600 rpm; the screen cylinder rotates at 1-20 rpm, preferably 5-15 rpm; the compressed air velocity is 10-30 m / s, preferably 15-25 m / s; and the size of the waste agricultural film fragments is 5-20 cm. This ensures optimal dry cleaning results and stable equipment operation.

[0058] Thirdly, the present invention provides a device for separating waste agricultural film and straw, comprising:

[0059] Crushing equipment is used to crush waste agricultural film mixture into small-sized film fragments.

[0060] The screening and air separation equipment is located below the outlet of the crushing equipment and consists of a multi-layer vibrating screen, a discharge conveyor belt, and a multi-stage exhaust fan. The screen openings of the multi-layer vibrating screen, which is arranged vertically, are progressively smaller. A discharge conveyor belt is located below the tail of the vibrating screen, and a sand and soil bin is located at the bottom of the multi-layer vibrating screen. The air inlets of the multi-stage exhaust fan are arranged sequentially above the multi-layer vibrating screen. The screening and air separation equipment is used to screen the film fragments and straw from the crushing equipment and to remove the film fragments from each stage of the vibrating screen through negative pressure.

[0061] The fine separation equipment consists of at least one dry cleaning agricultural film drum screen as described in the first aspect, used to further dry clean and remove dust from agricultural film materials containing dust.

[0062] Preferably, the waste agricultural film and straw separation device provided by the present invention further includes a shearing device and a conveyor belt for pre-treatment and conveying of the waste agricultural film mixture. After pre-treatment by cutting the waste agricultural film mixture, the length of the agricultural film material is 20-120cm, preferably 20-80cm.

[0063] In this invention, the crushing equipment includes a shell and a rotary cutter inside the shell. The top is provided with a mixture inlet and the bottom is provided with a crushed material outlet. The motor drives the rotary cutter to rotate and crush the mixture into small-sized crushed film materials.

[0064] Preferably, the crushing equipment includes a shell and a rotary cutter inside the shell, with a material inlet at the top and a crushed material outlet at the bottom. The motor drives the rotary cutter to rotate via a shaft to crush the mixture into small-sized crushed materials.

[0065] Preferably, a screen or screen plate is provided between the rotary cutter and the crushed material outlet, and the screen or screen plate has holes with a diameter of 10-20 cm. Preferably, the screen or screen plate surrounds the rotary cutter to control the size of the discharged crushed material. Material larger than the hole diameter will continue to be crushed, while material smaller than the hole diameter will pass smoothly through the screen plate and be discharged. The casing is the external structure of the crusher, which protects and supports the internal components, prevents material leakage, and ensures operational safety.

[0066] Preferably, the crushing equipment has 3-30 rows, more preferably 3-18 rows of rotary cutters along the axis of rotation, and the distance between two adjacent rows of rotary cutters is 4-20cm, more preferably 4-15cm.

[0067] Waste agricultural film and a mixture containing cotton straw are fed into a crushing device and cut into small-sized materials. After crushing, the length is 3-20cm, preferably 5-10cm. The crusher speed is controlled at 800-1500r / min, preferably 900-1300r / min.

[0068] Preferably, the screening and air separation equipment includes 2-4 layers of vibrating screens, with 3-7 stages of exhaust fan inlets arranged sequentially on the multi-layer vibrating screens; the screen openings of the multi-layer vibrating screens decrease in size from top to bottom. The exhaust fan inlets are arranged sequentially above the multi-layer vibrating screens and the agricultural film conveying components. This invention does not limit the specific arrangement.

[0069] In one embodiment, the screening and air separation equipment has two layers of vibrating screens arranged from top to bottom. The two layers of vibrating screens are inclined downward at an angle of 0-10 degrees to the horizontal plane. The length ratio of the first layer of vibrating screens to the second layer of vibrating screens is 1:1.5-3. A discharge conveyor belt is arranged downstream of the second layer of vibrating screens. A straw collection bin is arranged downstream of the discharge conveyor belt.

[0070] Preferably, the first layer of vibrating screen has rectangular screen holes with a length of 10-40cm, preferably 15-35cm, and a width of 1-3cm; the second layer of vibrating screen has circular screen holes with a diameter of 2-10mm, preferably 4-8mm.

[0071] In the aforementioned screening and air separation equipment, preferably, the first layer of vibrating screen has rectangular screen holes arranged longitudinally, which facilitates the passage of rod-shaped straw while restricting the passage of sheet-shaped membranes. The major axis dimension of the screen holes in the first layer of vibrating screen is 10-40cm, preferably 15-35cm; the minor axis dimension is 1-3cm, preferably 2cm. The second layer of vibrating screen has circular screen holes with a diameter of 2-10mm, preferably 4-8mm. This facilitates the passage of fine impurities such as soil particles and stones, while restricting the passage of straw.

[0072] In one embodiment, the screening and air separation equipment includes two layers of vibrating screens and seven stages of exhaust fans. The air inlet cross-section of the exhaust fans is a rectangle with a length of 1-3m and a width of 30-50cm. The exhaust ports of the first to third stages of exhaust fans are located above the first layer of vibrating screens, at a distance of 5-80cm, preferably 10-50cm. The air inlets of the fourth and fifth stages of exhaust fans are located above the second layer of vibrating screens, at a distance of 5-80cm, preferably 10-50cm. The air inlets of the sixth and seventh stages of exhaust fans are located above the discharge conveyor belt, at a distance of 5-80cm, preferably 10-50cm.

[0073] The screening and air separation equipment is equipped with a motor and a vibrating screen frame. The motor drives the vibrating screen frame to vibrate, and the multi-layer vibrating screen is installed on the vibrating screen frame.

[0074] In one embodiment of the application method of the screening and air separation equipment provided by the present invention, a series of exhaust fans of levels one to seven are used to ventilate the first layer of vibrating screen, the second layer of vibrating screen, and the discharge conveyor belt. The vibration frequency of the vibrating screen is controlled at 0.5-8 times / s, preferably 0.5-4 times / s.

[0075] The inlet air velocity of the first to seventh stage exhaust fans decreases progressively during operation, maximizing the removal of agricultural film fragments while minimizing the possibility of cotton being accidentally sucked into the fans. Preferably, the inlet air velocity of the first stage exhaust fan is controlled at 2-5 m / s, the second stage exhaust fan at 1.5-4.5 m / s, the third stage exhaust fan at 1-4 m / s, the fourth stage exhaust fan at 0.5-3.5 m / s, and the fifth to seventh stage exhaust fans at 0-3 m / s.

[0076] Fourthly, the present invention provides a method for separating waste agricultural film and straw, using the above-mentioned waste agricultural film and straw separation device, comprising the following steps:

[0077] S1. Waste agricultural film mixed raw material enters the crushing equipment through the material inlet, and the waste agricultural film mixed raw material is crushed into film fragments with a size of 5-20cm and discharged through the outlet;

[0078] S2. The crushed film material discharged from the crushing equipment falls onto the first layer of vibrating screen of the screening and air separation equipment. After screening, it falls onto the next layer of vibrating screen. The mixture of crushed agricultural film is sucked away by the negative pressure of the exhaust fan above the multi-layer vibrating screen. The cotton straw is put into the discharge conveyor belt at the tail of the multi-layer vibrating screen, and the sand falls into the sand bin at the bottom.

[0079] S3. The mixture of broken agricultural film collected by the air separation equipment is gathered and introduced into the dry cleaning agricultural film drum screen of the fine separation equipment. The mixture of broken agricultural film enters the drum screen through the feed hopper. Compressed air is introduced into the protective cover and into the drum screen cylinder. The motor drives the drum screen to rotate. The mixture of broken agricultural film is de-dusted under the continuous impact of the central stirring bar and the impact of compressed air, and cleaned broken agricultural film is obtained. The dust blown out through the exhaust dust removal port is further processed.

[0080] Optionally, the rotational speed of the drum screen is in the range of 10-200 rpm, preferably 20-180 rpm. The operating time of the drum screen is 1-20 minutes.

[0081] In this invention, the waste agricultural film refers to plastic films used in agricultural production, including films used for mulching and greenhouse coverings, as well as plastic films from household waste. These include ordinary polyethylene mulch film, polyvinyl chloride agricultural film, ethylene-vinyl acetate copolymer agricultural film, polypropylene agricultural film, etc.

[0082] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings, but this does not constitute a limitation on the present invention.

[0083] Appendix Figure 1 , 2 The attached images show the front and top views of a dry-cleaning agricultural film drum screen. Figure 1 , 2As shown, the dry cleaning agricultural film rotary screen consists of a rotary screen and a protective cover 5. In the rotary screen, the screen cylinder 2 is mounted on a support 4, with the central axis of the screen cylinder forming an angle of 5-30 degrees with the horizontal plane. A central stirring rod 3 is installed axially inside the screen cylinder, consisting of a main rod and a support rod. A feed hopper 1 is located at the top of the screen cylinder, and a discharge bin 6 is located at the bottom. The screen cylinder 2 and the central stirring rod 3 are driven by motors. The protective cover 5 completely encloses the rotary screen and has three sets of air inlets: a first set at the top, a second set on each side, and a third set on the sides. Multiple exhaust and dust removal ports 10 are located at the bottom of the protective cover 5. The feed hopper 1 and the discharge bin 6 extend out of the protective cover 5 and are equipped with openable / closed openings.

[0084] Appendix Figure 3 A schematic diagram of the device for separating waste agricultural film from cotton straw is attached. Figure 3 As shown, the upper part of the waste agricultural film and cotton straw separation device is a crushing device 12, the top of which is a feed inlet 11. Below the outlet of the crushing device 2 is a screening device. The motor 14 drives the multi-layer vibrating screen to move. The screen openings of the first layer vibrating screen 13 and the second layer vibrating screen 14, arranged from top to bottom, are progressively smaller. A sand bin 23 is provided at the bottom of the multi-layer vibrating screen. The tail of the vibrating screen is connected to the discharge conveyor belt 22. The air inlets of the first to seventh stage exhaust fans are arranged sequentially above the first layer vibrating screen 13, the second layer vibrating screen 14 and the discharge conveyor belt 15. A straw collection bin 24 is provided below the tail of the discharge conveyor belt 15.

[0085] Appendix Figure 2 A diagram showing the distribution of the first-layer vibrating screen and the exhaust fan inlet is attached. Figure 3 The diagram showing the distribution of the second-layer vibrating screen and the exhaust fan inlet is attached. Figure 2 , 3 As shown, the first layer of vibrating screen has air inlets 15, 16, and 17 for stages 1-3 arranged sequentially; the second layer of vibrating screen has air inlets 18 and 19 for stages 4-5 arranged sequentially above it; and the discharge conveyor belt 15 has air inlets 20 and 21 for stages 6-7 arranged above it. The screening and air separation equipment is used to screen film fragments from the crushing equipment and to remove agricultural film fragments from each layer of vibrating screens using negative pressure. The screen holes 26 of the first layer of vibrating screen are rectangular, and the screen holes 27 of the second layer of vibrating screen are circular.

[0086] The aforementioned fine separation equipment consists of at least one dry-cleaning agricultural film drum screen, and multiple dry-cleaning agricultural film drum screens can be connected in parallel or series. It is used to remove dust from agricultural film fragments. Figure 6 A schematic diagram of the crushing equipment is attached. Figure 6As shown, the crushing equipment includes a housing 31 and a rotary cutter 32 inside the housing. The motor drives the rotary cutter to rotate and crush the mixture into small-sized fragments. The top of the housing has a mixture inlet 33 and the bottom has a fragment outlet 34. A screen plate or screen 35 is provided between the rotary cutter 32 and the fragment outlet 34 to control the output size.

[0087] The following examples further illustrate the technical solutions and effects of the waste agricultural film dry cleaning and dust removal device and method, and the waste agricultural film and cotton straw separation device and method provided by the present invention.

[0088] The method for analyzing the composition of waste agricultural film mixed raw materials is as follows:

[0089] (1) Sample weighing

[0090] A certain amount of sample was randomly selected from the waste agricultural film mixture to be analyzed, and its total weight was weighed using a balance and recorded as M0.

[0091] (2) Cleaning treatment

[0092] Place the weighed sample into a cleaning container, add an appropriate amount of water, and thoroughly clean the material. Stir appropriately during the cleaning process to remove dirt, dust, and other impurities adhering to the surface.

[0093] (3) Drying treatment

[0094] After washing, drain the water from the materials and then put them into an oven to dry. Set the oven temperature to 70℃ and dry for 4 hours.

[0095] (4) Manual sorting

[0096] The dried and cooled materials are manually sorted to remove straw, waste agricultural film, cotton and other impurities.

[0097] (5) Weighing and Analysis

[0098] The sorted straw, waste agricultural film and cotton were weighed separately and their weights were recorded as M1 (straw), M2 (waste agricultural film) and M3 (cotton).

[0099] Based on the weighing results, calculate the percentage content of each component:

[0100] Straw content percentage = (M1 / M0) × 100%

[0101] Percentage of waste agricultural film content = (M2 / M0) × 100%

[0102] Cotton content percentage = (M3 / M0) × 100%

[0103] Dust and other impurities content percentage = 100% - (straw content percentage + waste agricultural film content percentage + cotton content percentage)

[0104] (6) Repeat (1)-(5) five times to calculate the average percentage of each component.

[0105] Example 1

[0106] Waste agricultural film and straw separation device as shown in the attached document Figure 3 As shown.

[0107] The crushing equipment used includes a shell and a rotary cutter inside the shell, with 12 rows of cutters arranged along the axial direction and the distance between two adjacent rows of rotary cutters being 8 cm.

[0108] The screening and air separation equipment uses a two-layer vibrating screen and a 1-7 stage exhaust fan, arranged as shown in the attached figure. Figure 4 , 5 As shown, the first and second vibrating screens are horizontally arranged. The first vibrating screen has rectangular screen holes, 15×2cm; the second vibrating screen has circular screen holes, 5mm in diameter. The air inlets of the first to third stage exhaust fans are sequentially located above the first vibrating screen, 20cm away; the fourth and fifth stage exhaust fans are located above the second vibrating screen, 20cm away; and the sixth and seventh stage exhaust fans are located above the material conveying components, 20cm away from the first vibrating screen. The air inlets of the first to seventh stage exhaust fans are rectangular, with dimensions of 2m in length and 40cm in width.

[0109] In the dry cleaning agricultural film drum screen, the screen cylinder has a diameter of 1m and a length of 5m. The screen cylinder is placed at an angle, with the axial angle between the screen cylinder and the horizontal plane being 15°. The size of the screen holes on the screen cylinder is 7mm.

[0110] Waste agricultural film mixture (taken from a waste agricultural film recycling site in Aksu, Xinjiang) enters the crushing equipment through inlet 1 and is crushed into a mixture of shredded agricultural film. The mixture falls through two layers of screening screens for sieving, with sand and soil falling into the bottom sand bin. The air velocity at the inlet of the first to seventh stage exhaust fans is adjusted, and the shredded agricultural film material is extracted and enriched by the exhaust fans in the air classifier. Straw and impurities on the second vibrating screen are sent to the straw collection bin 12 via the discharge conveyor belt 15, resulting in straw discharge. The shredded agricultural film material enriched by the air classifier is loaded into the drum screen of the dry-washing agricultural film drum screen. Compressed air is introduced through the air inlet of the shroud, the drum screen is turned on, and the central stirring rod is activated. Under the action of the central stirring rod and high-speed air, dust in the shredded agricultural film material is removed. Shredded agricultural film is discharged from the discharge bin, with the size of the film fragments ranging from 5-20 cm.

[0111] The composition of waste agricultural film raw materials is shown in Table 1. The composition of the shredded agricultural film and straw outputs is analyzed. The operating conditions are shown in Table 2, and the composition of the shredded agricultural film and straw outputs is shown in Tables 4 and 6.

[0112] Example 2

[0113] The waste agricultural film mixture, the waste agricultural film and straw separation device, and the separation steps are the same as in Example 1. The difference is that the air velocity at the inlet of the first to seventh stage exhaust fans is different. The operating conditions are shown in Table 2, and the composition of the shredded agricultural film and straw outputs are shown in Tables 4 and 6.

[0114] Example 3

[0115] The waste agricultural film mixture, the waste agricultural film and straw separation device, and the separation steps are the same as in Example 1. The difference is that the processing capacity of the drum screen in the dry-washing agricultural film drum screen is different. The operating conditions are shown in Table 2, and the composition of the shredded agricultural film output and straw output are shown in Tables 4 and 6.

[0116] Example 4

[0117] The waste agricultural film mixture, the waste agricultural film and straw separation device, and the separation steps are the same as in Example 1. The difference is that the compressed air velocity introduced into the dry-washing agricultural film drum screen is different. The operating conditions are shown in Table 2, and the composition of the shredded agricultural film and straw outputs are shown in Tables 4 and 6.

[0118] Example 5

[0119] The waste agricultural film mixture, the waste agricultural film and straw separation device, and the separation steps are the same as in Example 1. The difference is that the rotation speed of the drum screen in the dry-washing agricultural film drum screen is different. The operating conditions are shown in Table 3, and the composition of the shredded agricultural film output and straw output are shown in Tables 5 and 7.

[0120] Example 6

[0121] The waste agricultural film mixture, the waste agricultural film and straw separation device, and the separation steps are the same as in Example 1. The difference is that the rotation speed of the central stirring rod of the dry-washing agricultural film drum screen is different. The operating conditions are shown in Table 3, and the composition of the shredded agricultural film and straw outputs are shown in Tables 5 and 7.

[0122] Example 7

[0123] The waste agricultural film mixture, the waste agricultural film and straw separation device, and the separation steps are the same as in Example 1. The difference is that the residence time of the raw materials in the dry-washed agricultural film drum screen is different. The operating conditions are shown in Table 3, and the composition of the shredded agricultural film output and straw output are shown in Tables 5 and 7.

[0124] Example 8

[0125] The waste agricultural film mixture, the waste agricultural film and straw separation device, and the separation steps are the same as in Example 1. The difference is that the fine separation equipment uses a conventional drum screen, which is not equipped with a protective cover, and there is no central stirring rod or compressed air blowing and extraction in the drum screen. The operating conditions are shown in Table 3, and the composition of the waste agricultural film and straw outputs are shown in Tables 5 and 7.

[0126] Comparative Example 1

[0127] The waste agricultural film mixture raw material, the waste agricultural film and straw separation device, and the separation steps are the same as in Example 1. The difference is that the air velocity at the inlet of the exhaust fans in stages 1-7 is different, the fine separation equipment uses a drum screen, the drum screen is not equipped with a protective cover, there is no stirring rod in the drum screen and no compressed air blowing in and out, the residence time of the material in the drum screen is shortened, and the drum screen speed is low. The operating conditions are shown in Table 3, and the composition of the shredded agricultural film output and straw output are shown in Tables 5 and 7.

[0128] Table 1

[0129] Composition / Weight % Waste agricultural film raw materials plastic film 10.3 sandy soil 53.2 straw 35.9 Waste plastic film dimensions, in meters 5-10

[0130] Table 2

[0131]

[0132] Table 3

[0133]

[0134] Table 4. Agricultural film fragment output

[0135] Example 1 Example 2 Example 3 Example 4 Example 5 Agricultural film output*, kg 10.6 11.1 10.9 10.9 11.0 Agricultural film output composition Waste plastic film, wt% 97.2 92.7 94.5 94.7 94 Sand, wt% 2.1 3.8 4.7 4.4 5.1 Straw, wt% 0.7 3.5 0.8 0.9 0.9

[0136] *The processing capacity of the waste agricultural film mixed raw material is 100kg.

[0137] Table 5. Agricultural film fragment output

[0138] Example 6 Example 7 Example 8 Comparative Example 1 Agricultural film output*, kg 11.0 11.0 11.9 12.5 Agricultural film output composition Waste plastic film, wt% 94 93.3 86.4 82.3 Sand, wt% 5.2 5.8 12.8 16.3 Straw, wt% 0.8 0.9 0.8 1.4

[0139] *The processing capacity of the waste agricultural film mixed raw material is 100kg.

[0140] Table 6 Straw Output

[0141] Example 1 Example 2 Example 3 Example 4 Example 5 Straw output*, kg 39.4 39.9 39.5 39.5 39.4 Straw output composition Waste plastic film, wt% 0.4 0.74 0.45 0.48 0.42 Sand, wt% 8.50 9.30 8.60 8.56 8.46 Straw, wt% 91.1 89.96 90.95 90.96 91.12

[0142] *The processing capacity of the waste agricultural film mixed raw material is 100kg.

[0143] Table 7

[0144] Example 6 Example 7 Example 8 Comparative Example 1 Straw output*, kg 39.6 39.5 39.6 42.4 Straw output composition Waste plastic film, wt% 0.46 0.42 0.43 2.81 Sand, wt% 8.89 8.64 8.94 12.59 Straw, wt% 90.65 90.94 90.63 84.6

[0145] *The processing capacity of the waste agricultural film mixed raw material is 100kg.

[0146] In Examples 1-7, the sand content in the treated agricultural film output was 2.1-5.8 wt%, and the residual straw content was less than 1.0 wt%, meeting the requirements for subsequent agricultural film recycling.

Claims

1. A dry-cleaning agricultural film drum screen, characterized in that, include: A drum screen has a screen cylinder mounted on a support. The angle between the central axis of the screen cylinder and the horizontal plane is 5-30 degrees. A central stirring rod is provided along the axial direction inside the screen cylinder. A feed hopper is provided at the top of the screen cylinder, and a discharge bin is provided at the bottom. The screen cylinder and the stirring rod are driven to rotate by a motor. The protective cover encloses the drum screen and has multiple air inlets and at least one dust extraction port. The feed hopper and discharge bin of the drum screen extend out of the protective cover and are provided with openable and closable openings.

2. The dry cleaning agricultural film drum screen according to claim 1, characterized in that, The sieve cylinder refers to a cylindrical sieve, and the size of the sieve holes on the sieve cylinder is 5-10mm; Preferably, the screen is made of woven steel wire.

3. The dry cleaning agricultural film drum screen according to claim 1 or 2, characterized in that, The central stirring rod consists of a main stirring rod and a supporting stirring rod. Preferably, multiple stirring rod supports are arranged in a spiral shape on the main stirring rod.

4. The dry cleaning agricultural film drum screen according to claim 1 or 2, characterized in that, The air inlets are distributed in three groups on the three sides of the protective cover, with each group containing 2 to 8 air inlets.

5. The dry-cleaning agricultural film drum screen according to claim 1 or 2, characterized in that, The exhaust dust removal port is connected to a dust removal device, which is a bag filter or a cyclone dust collector.

6. A method for dry cleaning waste agricultural film, using the dry cleaning agricultural film drum screen according to any one of claims 1-5, characterized in that, The mixture of shredded agricultural film enters the drum screen through the feed hopper. Compressed air is introduced into the protective cover and then into the drum screen cylinder. The motor drives the drum screen to rotate. The agricultural film fragments are removed from the dust by the continuous impact of the central stirring rod and the impact of the compressed air. The dust blown out through the exhaust dust removal port is then processed.

7. The method for dry cleaning waste agricultural film according to claim 6, characterized in that, The central stirring rod rotates at 100-1200 rpm; the sieve cylinder rotates at 1-20 rpm; the compressed air velocity is 10-30 m / s; and the size of the waste agricultural film fragments is 5-20 cm. Preferably, the central stirring rod rotates at 200-600 rpm, the sieve cylinder rotates at 5-15 rpm, and the compressed air velocity is 15-25 m / s.

8. A device for separating waste agricultural film and straw, characterized in that, include: Crushing equipment used for crushing waste agricultural film mixed raw materials; The screening and air separation equipment is located below the outlet of the crushing equipment and consists of a multi-layer vibrating screen, a discharge conveyor belt, and a multi-stage exhaust fan. The screen openings of the multi-layer vibrating screen, which is arranged vertically, are progressively smaller. A discharge conveyor belt is located below the tail of the vibrating screen, and a sand and soil bin is located at the bottom of the multi-layer vibrating screen. The air inlets of the multi-stage exhaust fan are arranged sequentially above the multi-layer vibrating screen. The screening and air separation equipment is used to screen the film fragments and straw from the crushing equipment and to remove the film fragments from each stage of the vibrating screen through negative pressure. The fine separation equipment comprises at least one dry cleaning agricultural film drum screen as described in any one of claims 1-5.

9. The waste agricultural film and straw separation device according to claim 8, characterized in that, The crushing equipment includes a shell and a rotary cutter inside the shell. The top is provided with a mixture inlet and the bottom is provided with a crushed material outlet. The motor drives the rotary cutter to rotate and crush the mixture into small-sized crushed material. Preferably, the crushing equipment is provided with 3-30 rows of cutters along the axial direction, more preferably 3-18 rows of rotary cutters; the distance between two adjacent rows of rotary cutters is 4-20cm, more preferably 4-15cm.

10. The waste agricultural film and straw separation device according to claim 8, characterized in that, The screening and air separation equipment is provided with 2-4 layers of vibrating screens, with the screen openings of the multi-layer vibrating screens decreasing in size from top to bottom; and 3-7 levels of exhaust fan inlets are arranged sequentially on the multi-layer vibrating screens.

11. The waste agricultural film and straw separation device according to claim 8, characterized in that, The screening and air separation equipment has two layers of vibrating screens arranged from top to bottom. The two layers of vibrating screens are inclined downward at an angle of 0-10 degrees to the horizontal plane. The length ratio of the first layer of vibrating screens to the second layer of vibrating screens is 1:1.5-3. A discharge conveyor belt is set downstream of the second layer of vibrating screens. Preferably, the first layer of vibrating screen has rectangular screen holes with a length of 10-40cm, preferably 15-35cm, and a width of 1-3cm; the second layer of vibrating screen has circular screen holes with a diameter of 2-10mm, preferably 4-8mm.

12. The waste agricultural film and straw separation device according to claim 8, characterized in that, The screening and air separation equipment includes two layers of vibrating screens and seven stages of exhaust fans. The air inlet of each exhaust fan has a rectangular cross-section that is 1-3m long and 30-50cm wide. The exhaust ports of stages 1-3 are located above the first layer of vibrating screens, at a distance of 5-80cm, preferably 10-50cm. The air inlets of stages 4-5 are located above the second layer of vibrating screens, at a distance of 5-80cm, preferably 10-50cm. The air inlets of stages 6-7 are located above the discharge conveyor belt, at a distance of 5-80cm, preferably 10-50cm.

13. A method for separating a mixture of waste agricultural film and straw, using the waste agricultural film and straw separation device as described in any one of claims 8-12, comprising the following steps: S1. Waste agricultural film mixed raw materials enter the crushing equipment through the material inlet and are crushed into film fragments with a size of 5-20cm; S2. The crushed film material discharged from the crushing equipment falls onto the first vibrating screen of the screening and air separation equipment. After screening, it falls onto the next vibrating screen in sequence. The negative pressure of the exhaust fan above the multi-layer vibrating screen is used to suck away the mixture of crushed agricultural film containing a small amount of cotton. The cotton straw is put into the discharge conveyor belt at the tail of the multi-layer vibrating screen, and the sand falls into the sand bin at the bottom. S3. The mixture of broken agricultural film collected by the exhaust fan of the air separation equipment is gathered and introduced into the dry cleaning agricultural film drum screen of the fine separation equipment. It enters the drum screen through the feed hopper. Compressed air is introduced into the protective cover and into the drum screen cylinder. The motor drives the drum screen to rotate. The waste agricultural film fragments are removed from the dust under the continuous impact of the central stirring rod and the impact of the compressed air, and clean broken agricultural film is obtained. The dust blown out through the exhaust dust removal port is further processed.

14. The method for separating waste agricultural film and straw mixture according to claim 13, characterized in that, When using the waste agricultural film and cotton straw separation device as described in claim 11 or 12, the vibration frequency of the vibrating screen is controlled at 0.5-8 times / s, preferably 0.5-4 times / s; The air inlet velocity of the first-stage exhaust fan is 2-5 m / s, the air inlet velocity of the second-stage exhaust fan is 1.5-4.5 m / s, the air inlet velocity of the third-stage exhaust fan is 1-4 m / s, the air inlet velocity of the fourth-stage exhaust fan is 0.5-3.5 m / s, and the air inlet velocity of the fifth- to seventh-stage exhaust fans is 0-3 m / s.

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