Granularity screening device for compound fertilizer granules

Abstract

The invention relates to the technical field of compound fertilizer production, in particular to a compound fertilizer particle size screening device which comprises a screening box, and the bottom end of the screening box is fixedly connected with a discharging cover; the two-time wind power screening mechanism comprises an upper air blower and a lower air blower which are used for blowing air to the fertilizer. The device can adaptively control the up-down vibration amplitude and frequency of the screening net according to the weight of the compound fertilizer, the up-down vibration amplitude and frequency are in direct proportion, the weight of the compound fertilizer is monitored through the PLC to change the current of the slide rheostat, then the rotating speed of the first motor and the electrifying amount of the electromagnet are controlled, the impact force and the moving range of the impact block on the screening net are adjusted, and the vibration amplitude is increased; meanwhile, the rotating frequency of the second motor is in direct proportion to the compound fertilizer particle amount, the screening net is driven to reciprocate front and back and left and right, and the screening efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of compound fertilizer production, and particularly relates to a particle size screening device for compound fertilizer particles. Background Art

[0002] Compound fertilizer refers to chemical fertilizer containing two or more nutrient elements (nitrogen, phosphorus, potassium). It has the advantages of high nutrient content, few by-products, good physical properties, etc. It can supply several nutrients to crops evenly at the same time, give full play to the interaction between nutrient elements, have a high effective component, improve the utilization rate of fertilizer, and promote high and stable yields of crops. During the production process of compound fertilizer, particles of different particle sizes will be generated. Therefore, it is necessary to screen the compound fertilizer. Through screening, particles that do not meet the product particle size requirements can be separated, ensuring the consistency of the appearance and physical properties of the product, and facilitating storage, transportation and use.

[0003] Traditional screening devices mostly adopt a single mechanical screening method, relying on a vibration motor to drive the screen to vibrate to achieve particle screening. When facing compound fertilizer particles of different weights and quantities, this method cannot adaptively adjust the screening frequency and vibration amplitude. When the compound fertilizer particles are heavy and numerous, the screen is prone to clogging, resulting in a sharp drop in screening efficiency; while when the particles are light and few in quantity, the vibration amplitude and frequency of the screen are too large, causing energy waste and reducing screening efficiency. Summary of the Invention

[0004] Aiming at the above-mentioned shortcomings of the prior art, the present invention provides a particle size screening device for compound fertilizer particles, which can effectively solve the problem that the prior art cannot adaptively adjust the screening frequency and vibration amplitude.

[0005] To achieve the above purposes, the present invention is realized through the following technical solutions: The present invention provides a particle size screening device for compound fertilizer particles, comprising: A screening box, the bottom end of the screening box is fixedly connected with a discharge cover; A two-stage air screening mechanism, the two-stage air screening mechanism includes an upper air blower and a lower air blower for blowing air on the fertilizer; Adaptive filter screen screening mechanism, the adaptive filter screen screening mechanism includes an elastic rubber frame fixedly connected to the inner wall of the screening box, a screening net fixedly connected to the inner peripheral wall of the elastic rubber frame, an adjustment groove is opened on the outer wall of the screening box, a protective cover is fixedly connected to the outer wall of the screening box, a first motor is fixedly connected to the inner bottom wall of the protective cover, the output end of the first motor is fixedly connected to a rotating rod, two symmetrically arranged fixed shells are fixedly connected to the outer wall of the rotating rod, an electromagnet is fixedly connected to the inner bottom wall of the fixed shell, a plastic spring is fixedly connected to the outer wall of the electromagnet, the other end of the plastic spring is fixedly connected to a permanent magnet block, an impact block is fixedly connected to the outer wall of the permanent magnet block, the permanent magnet block is magnetically repelled by the electromagnet, collision blocks are fixedly connected to the outer side walls on both sides of the screening net, the impact block is in intermittent contact with the collision block, and the impact block is in sliding contact with the inner wall of the fixed shell.

[0006] Preferably, a feeding cover is fixedly connected to the top of the screening box near the upper part, a protective ring is fixedly connected to the outer wall of the screening box, a plurality of support legs are fixedly connected to the bottom end of the protective ring, and a transmission component is arranged between the two support legs.

[0007] Preferably, the two-stage wind screening mechanism further includes a discharge port opened on the inner wall of the screening box, a receiving box is fixedly connected to the outer wall of the discharge port, a discharge pipe is fixedly connected to the bottom end of the receiving box, and the upper air blower is at the same horizontal plane as the discharge port.

[0008] Preferably, an L-shaped baffle is fixedly connected to the outer wall of the support leg, the L-shaped baffle is composed of a long plate and a short plate, the outer wall of the long plate of the L-shaped baffle is fixedly connected to the lower air blower, an L-shaped receiving box is fixedly connected between the two support legs, a receiving port is opened on the outer wall of the L-shaped receiving box, the receiving port is opposite to the lower air blower and at the same horizontal plane, a feeding port is opened at the top end of the L-shaped receiving box, a baffle plate is fixedly connected to the top end of the L-shaped receiving box, the discharge end of the discharge pipe is above the feeding port, and a light-emitting lamp panel and a photosensitive resistor are respectively fixedly connected to the outer wall of the L-shaped baffle and the opposite outer wall of the L-shaped receiving box, and the light-emitting lamp panel and the photosensitive resistor are respectively directly above the receiving port and the lower air blower and at the same horizontal plane.

[0009] Preferably, the adaptive filter screen screening mechanism further includes two symmetrically arranged extension plates fixedly connected to one side outer wall of the screening net, a limiting hole is opened at the bottom end of the extension plate, two symmetrically arranged second motors are fixedly connected to the inner bottom wall of the protective cover, the output end of the second motor is fixedly connected to a circular plate, a limiting rod is fixedly connected to the eccentric position at the top end of the circular plate, the limiting rod is slidably connected to the limiting hole, and a limiting block is fixedly connected to the top end of the limiting rod.

[0010] Preferably, a fixed frame is fixedly connected to the inner wall of the screening box. Two symmetrically arranged adjustment openings are formed at the top end of the fixed frame. The fixed shell and the impact block rotate within the adjustment openings. A reset spring is commonly connected between the top end of the fixed frame and the bottom end of the screening mesh. An infrared emitter is embedded at the bottom end of the impact-receiving block, and an infrared receiver is fixedly connected to the end of the impact block away from the fixed shell.

[0011] Preferably, a conductive sheet is fixedly connected to the inner wall of one of the adjustment openings. A resistance plate that is in sliding contact with the conductive sheet is fixedly connected to the bottom end of the screening mesh. The conductive sheet and the resistance plate are electrically connected to a PLC controller to form a detection circuit. The conductive sheet and the resistance plate constitute a sliding rheostat. During the downward sliding process of the resistance plate on the conductive sheet, the resistance of the sliding rheostat in the detection circuit gradually decreases.

[0012] Preferably, a plurality of linearly arrayed support bars are fixedly connected to the inner wall of the fixed frame. Push rods are fixedly connected to the top ends of the support bars. The plurality of push rods respectively correspond to the mesh holes of the screening mesh. Two symmetrically arranged electromagnetic bars are fixedly connected to the top end of the fixed frame. Two symmetrically arranged permanent magnetic bars are fixedly connected to the bottom end of the screening mesh. The electromagnetic bars and the permanent magnetic bars are magnetically attracted to each other. The PLC controller is electrically connected to the electromagnetic bars and the electromagnets to form an adjustment circuit. The PLC controller is electrically connected to the first motor and the second motor to form a control circuit. The PLC controller is electrically connected to the upper air blower and the lower air blower to form a start-stop circuit. The PLC controller is electrically connected to the infrared emitter and the infrared receiver to form a positioning circuit. The PLC controller is electrically connected to the light-emitting lamp panel and the photoresistor to form a monitoring circuit.

[0013] The technical solution provided by the present invention has the following beneficial effects compared with the known prior art: 1. This device can adaptively control the up-and-down vibration amplitude and frequency of the screening mesh according to the weight (i.e., quantity) of the compound fertilizer, and the two are proportional. The PLC controller monitors the weight of the compound fertilizer to change the current of the sliding rheostat, and then controls the rotation speed of the first motor and the energization amount of the electromagnet, adjusts the impact force and moving range of the impact block on the screening mesh, and increases the vibration amplitude. At the same time, the rotation frequency of the second motor is also proportional to the amount of compound fertilizer particles, driving the screening mesh to reciprocate back and forth, greatly improving the screening efficiency.

[0014] 2. During the screening process of this device, a photosensitive resistor and a light-emitting lamp board are used to monitor the falling situation of particles. When the number of particles decreases and it is suspected that the screen is blocked, the PLC controller controls the first motor and the second motor to shut down, and energizes the electromagnetic strip. The electromagnetic strip attracts the permanent magnetic strip to move the screening net downward, allowing the push rod to insert into the screen holes to clean the blockage. Then, the current is slowly reduced, and the current of the sliding rheostat is detected again to continue screening, effectively solving the problem of screen blockage and ensuring the continuous and efficient progress of screening. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 is a three-dimensional structure schematic diagram of the present invention; Figure 2 is a partial cross-sectional three-dimensional structure schematic Figure 1 ; Figure 3 is a cross-sectional three-dimensional structure schematic diagram of the screening box of the present invention; Figure 4 is a partial three-dimensional structure schematic of the interior of the present invention Figure 1 ; Figure 5 is a partial three-dimensional structure schematic diagram of the screening box of the present invention; Figure 6 is a partial three-dimensional structure schematic of the interior of the present invention Figure 2 ; Figure 7 is a partial cross-sectional three-dimensional structure schematic Figure 2 ; Figure 8 is a cross-sectional three-dimensional structure schematic diagram of the fixed shell of the present invention.

[0017] Reference Numerals: 1, screening box; 2, discharge hood; 3, double air screening mechanism; 31, upper air blower; 32, lower air blower; 33, discharge port; 34, material collection box; 35, discharge pipe; 36, L-shaped baffle; 37, L-shaped material collection box; 38, material collection port; 39, feed port; 310, baffle plate; 311, light-emitting lamp panel; 312, photoresistor; 4, adaptive filter screen screening mechanism; 41, elastic rubber frame; 42, screening net; 43, adjustment groove; 44, protective cover; 45, permanent magnet strip; 46, first motor; 47, rotating rod; 48, fixed housing; 49, electromagnet; 410, plastic spring; 411, permanent magnet block; 412, impact block; 413, impacted block; 414, extension plate; 415, limiting hole; 416, second motor; 417, circular plate; 418, limiting rod; 419, limiting block; 4110, fixed frame; 4111, adjustment opening; 4112, return spring; 4113, conductive sheet; 4114, resistance plate; 4115, support bar; 4116, push rod; 4117, electromagnetic strip; 5, blanking hood; 6, protective ring; 7, support leg; 8, transmission assembly. Detailed Embodiment

[0018] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] The present invention will be further described below with reference to the embodiments.

[0020] Embodiment: Refer to Figures 1 to 8 , a particle size screening device for compound fertilizer particles, comprising: A screening box 1, the bottom end of the screening box 1 is fixedly connected with a discharge hood 2, the top of the screening box 1 near the upper part is fixedly connected with a blanking hood 5, the outer wall of the screening box 1 is fixedly connected with a protective ring 6, the bottom end of the protective ring 6 is fixedly connected with a plurality of support legs 7, and a transmission assembly 8 is arranged between two support legs 7.

[0021] A double air screening mechanism 3, the double air screening mechanism 3 includes an upper air blower 31 and a lower air blower 32 for blowing air on the fertilizer, the double air screening mechanism 3 further includes a discharge port 33 opened on the inner wall of the screening box 1, the outer wall of the discharge port 33 is fixedly connected with a material collection box 34, the bottom end of the material collection box 34 is fixedly connected with a discharge pipe 35, and the upper air blower 31 and the discharge port 33 are on the same horizontal plane.

[0022] An L-shaped baffle 36 is fixedly connected to the outer wall of the support leg 7. The L-shaped baffle 36 consists of two plates with one long and one short. The outer wall of the long plate of the L-shaped baffle 36 is fixedly connected to the lower air blower 32. A fixed connection is provided between two support legs 7 with an L-shaped material collection box 37. A material collection port 38 is provided on the outer wall of the L-shaped material collection box 37. The material collection port 38 faces the lower air blower 32 and is on the same horizontal plane. An inlet port 39 is provided at the top of the L-shaped material collection box 37. A baffle 310 is fixedly connected to the top of the L-shaped material collection box 37. The discharge end of the discharge pipe 35 is above the inlet port 39. Light-emitting lamp panels 311 and photoresistors 312 are respectively fixedly connected to the outer walls of the L-shaped baffle 36 and the opposite outer wall of the L-shaped material collection box 37, and the light-emitting lamp panels 311 and photoresistors 312 are respectively directly above the material collection port 38 and the lower air blower 32 and on the same horizontal plane.

[0023] The adaptive filter screen screening mechanism 4 includes an elastic rubber frame 41 fixedly connected to the inner wall of the screening box 1. A screening net 42 is fixedly connected to the inner peripheral wall of the elastic rubber frame 41. An adjustment groove 43 is provided on the outer wall of the screening box 1. A protective cover 44 is fixedly connected to the outer wall of the screening box 1. A first motor 46 is fixedly connected to the inner bottom wall of the protective cover 44. The output end of the first motor 46 is fixedly connected to a rotating rod 47. Two symmetrically arranged fixed shells 48 are fixedly connected to the outer wall of the rotating rod 47. An electromagnet 49 is fixedly connected to the inner bottom wall of the fixed shell 48. A plastic spring 410 is fixedly connected to the outer wall of the electromagnet 49. The other end of the plastic spring 410 is fixedly connected to a permanent magnet 411. An impact block 412 is fixedly connected to the outer wall of the permanent magnet 411. The permanent magnet 411 and the electromagnet 49 repel each other magnetically. Impact receiving blocks 413 are fixedly connected to the outer walls on both sides of the screening net 42. The impact block 412 is in intermittent contact with the impact receiving block 413, and the impact block 412 is in sliding contact with the inner wall of the fixed shell 48.

[0024] The adaptive filter screen screening mechanism 4 further includes two symmetrically arranged extension plates 414 fixedly connected to one of the outer walls of the screening net 42. A limit hole 415 is provided at the bottom end of the extension plate 414. Two symmetrically arranged second motors 416 are fixedly connected to the inner bottom wall of the protective cover 44. The output end of the second motor 416 is fixedly connected to a circular plate 417. A limit rod 418 is fixedly connected to the eccentric position at the top of the circular plate 417. The limit rod 418 is slidably connected to the limit hole 415. A limit block 419 is fixedly connected to the top of the limit rod 418.

[0025] The inner wall of the screening box 1 is fixedly connected with a fixed frame 4110. Two symmetrically arranged adjusting openings 4111 are formed at the top end of the fixed frame 4110. The fixed shell 48 and the impact block 412 rotate within the adjusting opening 4111. A reset spring 4112 is jointly connected between the top end of the fixed frame 4110 and the bottom end of the screening mesh 42. An infrared emitter is embedded at the bottom end of the impact-receiving block 413, and an infrared receiver is fixedly connected to the end of the impact block 412 away from the fixed shell 48.

[0026] The inner wall of one of the adjusting openings 4111 is fixedly connected with a conductive sheet 4113. A resistor plate 4114 that is in sliding contact with the conductive sheet 4113 is fixedly connected to the bottom end of the screening mesh 42. The conductive sheet 4113 and the resistor plate 4114 are electrically connected to a PLC controller to form a detection circuit. The conductive sheet 4113 and the resistor plate 4114 constitute a sliding rheostat. During the process of the resistor plate 4114 sliding downward on the conductive sheet 4113, the resistance of the sliding rheostat in the detection circuit gradually decreases.

[0027] A plurality of linearly arrayed support bars 4115 are fixedly connected to the inner wall of the fixed frame 4110. The top ends of the support bars 4115 are fixedly connected with a plurality of push rods 4116. The plurality of push rods 4116 respectively correspond to the mesh holes of the screening mesh 42. Two symmetrically arranged electromagnetic bars 4117 are fixedly connected to the top end of the fixed frame 4110. Two symmetrically arranged permanent magnetic bars 45 are fixedly connected to the bottom end of the screening mesh 42. The electromagnetic bars 4117 and the permanent magnetic bars 45 are magnetically attracted to each other. The PLC controller is electrically connected to the electromagnetic bars 4117 and the electromagnet 49 to form an adjustment circuit. The PLC controller is electrically connected to the first motor 46 and the second motor 416 to form a control circuit. The PLC controller is electrically connected to the upper air blower 31 and the lower air blower 32 to form a start-stop circuit. The PLC controller is electrically connected to the infrared emitter and the infrared receiver to form a positioning circuit. The PLC controller is electrically connected to the light-emitting lamp panel 311 and the photoresistor 312 to form a monitoring circuit.

[0028] The working principle of the present invention is as follows: Before the compound fertilizer particles enter the feeding cover 5 (the compound fertilizer particles are not continuously fed, but intermittently fed), start the blower first, and then put the compound fertilizer particles into the feeding cover 5. With the start of the blower, a horizontal airflow will be generated, blowing a strong wind towards the fertilizer particles (the magnitude of this wind has been pre-tested and can blow the smaller compound fertilizer particles that do not meet the standards to one side). Under the action of the wind, those particles with lighter mass, such as the dust generated during the production process, or the parts that are not fully formed and have small particles due to process problems, will be blown towards the direction of the discharge port 33. Since the upper blower 31 and the discharge port 33 are carefully designed on the same horizontal plane, when these light particles reach the corresponding position under the push of the wind, they can smoothly enter the discharge port 33 without any obstruction. Once they enter the discharge port 33, they will fall into the receiving box 34 connected to it for temporary storage, and finally be discharged from the device through the discharge pipe 35 at the bottom of the receiving box 34, completing the preliminary screening of the light particles in this stage; The screened compound fertilizer particles will fall on the screening mesh 42. The weight of the compound fertilizer will press down the screening mesh 42, thereby driving the resistor plate 4114 to move downward synchronously, and then changing the magnitude of the current passing through the rheostat. Then, through the magnitude of the rheostat, the current monitoring module in the PLC controller can monitor the magnitude of the current passing through the rheostat, and then feedback the weight of the compound fertilizer particles. Then, according to the weight of the compound fertilizer, the up and down vibration amplitude and frequency of the screening mesh 42 are adaptively controlled. The weight of the compound fertilizer (i.e., the quantity of the compound fertilizer) is proportional to the vibration amplitude and frequency of the screening mesh 42. The reason is that when the weight and quantity of the compound fertilizer particles are large, increasing the vibration amplitude and frequency of the screening mesh 42 has multiple important effects. It can cause more relative movement between the particles, effectively avoid mutual extrusion and blockage, make it easier for small particles to pass through the screen, greatly improve the screening efficiency, and accelerate the screening process.

[0029] At the same time, start the first motor 46 through the PLC controller and control the rotation speed of the first motor 46 (proportional to the weight of the compound fertilizer particles). With the start of the first motor 46, the output shaft of the first motor 46 drives the rotating rod 47 to start rotating, and then drives the two symmetrical fixed shells 48 fixedly connected to the rotating rod 47 to perform circular motion together with the rotating rod 47, thereby driving the impact block 412 to intermittently contact the impacted block 413 periodically. Each impact will apply an instantaneous impact force to the screening mesh 42, causing the screening mesh 42 to generate high-frequency vibration, thereby improving the screening efficiency and quality.

[0030] An electromagnet 49 is installed on the inner bottom wall of the fixed housing 48. When the electromagnet 49 is powered on, a strong magnetic field will be generated immediately. Since the electromagnet 49 and the permanent magnet block 411 repel each other magnetically, the more compound fertilizer there is, the greater the power consumption of the electromagnet 49, that is, the greater the repulsive force on the permanent magnet block 411, which causes the impact block 412 to move upward a longer distance. Therefore, the range of up and down movement of the screening mesh 42 is larger, achieving the effect of increasing the vibration amplitude and further enhancing the screening effect.

[0031] At the same time, the second motor 416 is started. Through the start of the second motor 416, the output end drives the circular plate 417 to start rotating. As the circular plate 417 rotates, it further drives the limiting rod 419 to rotate synchronously, and then makes the screening mesh 42 move back and forth in all directions. The rotation frequency of the second motor 416 is proportional to the compound fertilizer particles. The reason is that more compound fertilizer particles need to be quickly screened back and forth in all directions, which is beneficial to the screening of compound fertilizer particles.

[0032] Then the screened particles will be discharged through the discharge cover 2. The strong air flow blown out by the lower air blower 32 will conduct a secondary screening on these falling particles. Under the impact of the air flow, the remaining lighter particles will overcome gravity and change their movement trajectories, being blown towards the material receiving port 38 of the L-shaped material receiving box. When these particles reach the material receiving port 38, they will enter the L-shaped material receiving box and be collected. It is worth mentioning that a feeding port 39 is specially provided at the top of the L-shaped material receiving box. The material discharged from the discharge pipe 35 will also enter the L-shaped material receiving box along the feeding port 39, converging with the light particles screened out by the lower air blower 32 for unified collection.

[0033] Under normal circumstances, the light emitted by the light-emitting lamp panel 311 can smoothly irradiate the photoresistor 312; however, when there are particles passing through this area, the light will be blocked by the particles, and the light intensity received by the photoresistor 312 will change. This change in light intensity will be converted into an electrical signal and transmitted to the PLC controller. If the number of particles falling within a certain period of time decreases, it proves that there are fewer small particles being screened at this time. At this time, either the screening is completed or the screen mesh 42 opening is blocked. At this time, the first motor 46 and the second motor 416 need to be turned off. The timing for turning off the first motor 46 is when the infrared emitter and the infrared receiver are opposite, and at this time the impact block 412 faces downward. Therefore, the screen mesh 42 will not be blocked during the downward movement. Then, the electromagnetic strip 4117 is energized through the PLC controller, and the permanent magnet strip 45 is attracted by the electromagnetic strip 4117, thereby causing the screen mesh 42 to move downward. Then, the push rod 4116 is inserted into the holes of the screen mesh 42 to clean the holes of the screen mesh 42. Then, the current flowing through the electromagnetic strip 4117 is slowly reduced until it is completely de-energized. At this time, the current passing through the rheostat is detected, and then the screening continues. If still very few particles are screened out, it proves that the screening is completed. Then, through an external material extractor, it reaches into the screening box 1 to extract and collect the larger particles on the screen mesh 42.

[0034] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A particle size screening device for compound fertilizer particles, characterized in that: include: A screening box (1), wherein a discharge cover (2) is fixedly connected to the bottom end of the screening box (1); A two-stage wind screening mechanism (3), the two-stage wind screening mechanism (3) comprising an upper blower (31) and a lower blower (32) for blowing air on the fertilizer; An adaptive filter screen mechanism (4), the adaptive filter screen mechanism (4) comprising an elastic rubber frame (41) fixedly connected to the inner wall of a screening box (1), a screening net (42) fixedly connected to the inner peripheral wall of the elastic rubber frame (41), an adjustment groove (43) provided on the outer wall of the screening box (1), a protective cover (44) fixedly connected to the outer wall of the screening box (1), a first motor (46) fixedly connected to the inner bottom wall of the protective cover (44), a rotating rod (47) fixedly connected to the output end of the first motor (46), and two symmetrical fixed shells (48) fixedly connected to the outer wall of the rotating rod (47), The inner bottom wall of the fixed shell (48) is fixedly connected to an electromagnet (49), the outer wall of the electromagnet (49) is fixedly connected to a plastic spring (410), the other end of the plastic spring (410) is fixedly connected to a permanent magnet block (411), the outer wall of the permanent magnet block (411) is fixedly connected to an impact block (412), the permanent magnet block (411) and the electromagnet (49) repel each other magnetically, the outer walls of both sides of the screening net (42) are fixedly connected to impacted blocks (413), the impact blocks (412) are in intermittent contact with the impacted blocks (413), and the impact blocks (412) are in sliding contact with the inner wall of the fixed shell (48).

2. A particle size screening device for compound fertilizer particles according to claim 1, characterized in that: A material discharge cover (5) is fixedly connected to the top of the screening box (1), a protective ring (6) is fixedly connected to the outer wall of the screening box (1), a plurality of supporting legs (7) are fixedly connected to the bottom end of the protective ring (6), and a transmission component (8) is arranged between two of the supporting legs (7).

3. A particle size screening device for compound fertilizer particles according to claim 2, characterized in that: The two-stage wind screening mechanism (3) further comprises a discharge port (33) opened on the inner wall of the screening box (1); a material receiving box (34) is fixedly connected to the outer wall of the discharge port (33); a discharge pipe (35) is fixedly connected to the bottom end of the material receiving box (34); and the upper blower (31) and the discharge port (33) are located at the same horizontal plane.

4. A particle size screening device for compound fertilizer particles according to claim 3, characterized in that: An L-shaped baffle (36) is fixedly connected to the outer wall of the support leg (7), and the L-shaped baffle (36) is composed of two plates, one long and one short. The outer wall of the long plate of the L-shaped baffle (36) is fixedly connected to the lower blower (32), wherein an L-shaped material receiving box (37) is fixedly connected between the two support legs (7), and the outer wall of the L-shaped material receiving box (37) is provided with a material receiving opening (38), and the material receiving opening (38) is opposite to the lower blower (32) and is located in the same horizontal plane. The top end of the L-shaped material receiving box (37) is opened. A material feed port (39) is provided, a material baffle plate (310) is fixedly connected to the top of the L-shaped material receiving box (37), a material discharge end of the material discharge pipe (35) is located above the material feed port (39), an outer wall of the L-shaped baffle plate (36) and an outer wall of the L-shaped material receiving box (37) on the opposite side are respectively fixedly connected to a light-emitting lamp board (311) and a photoresistor (312), and the light-emitting lamp board (311) and the photoresistor (312) are respectively located directly above the material receiving port (38) and the lower blower (32), and are located on the same horizontal plane.

5. A particle size screening device for compound fertilizer particles according to claim 1, characterized in that: The adaptive filter screen screening mechanism (4) further comprises two symmetrical extension plates (414) fixedly connected to the outer wall of one side of the screening net (42), a limiting hole (415) being provided at the bottom end of the extension plate (414), two symmetrical second motors (416) being fixedly connected to the inner bottom wall of the protective cover (44), a circular plate (417) being fixedly connected to the output end of the second motor (416), a limiting rod (418) being fixedly connected to the eccentric portion of the top end of the circular plate (417), the limiting rod (418) being slidably connected to the limiting hole (415), and a limiting block (419) being fixedly connected to the top end of the limiting rod (418).

6. A particle size screening device for compound fertilizer particles according to claim 1, characterized in that: A fixing frame (4110) is fixedly connected to the inner wall of the screening box (1); two symmetrical adjustment openings (4111) are provided at the top of the fixing frame (4110); the fixing shell (48) and the impact block (412) rotate in the adjustment openings (4111); a return spring (4112) is commonly connected to the top of the fixing frame (4110) and the bottom of the screening net (42); an infrared transmitter is embedded at the bottom of the impact block (413); and an infrared receiver is fixedly connected to one end of the impact block (412) away from the fixing shell (48).

7. A particle size screening device for compound fertilizer particles according to claim 6, characterized in that: A conductive sheet (4113) is fixedly connected to the inner wall of one of the regulating ports (4111); a resistor plate (4114) in sliding contact with the conductive sheet (4113) is fixedly connected to the bottom end of the screening net (42); the conductive sheet (4113) and the resistor plate (4114) are electrically connected to a PLC controller to form a detection circuit; the conductive sheet (4113) and the resistor plate (4114) constitute a sliding rheostat; and during the downward sliding process of the resistor plate (4114) on the conductive sheet (4113), the resistance of the sliding rheostat in the detection circuit gradually decreases.

8. A particle size screening device for compound fertilizer particles according to claim 7, characterized in that: The inner wall of the fixed frame (4110) is fixedly connected to a plurality of support bars (4115) in a linear array, the top of the support bars (4115) is fixedly connected to a plurality of push rods (4116), the plurality of push rods (4116) respectively corresponding to the meshes of the screening net (42), the top of the fixed frame (4110) is fixedly connected to two symmetrical electromagnetic bars (4117), the bottom of the screening net (42) is fixedly connected to two symmetrical permanent magnetic bars (45), the electromagnetic bars (4117) and the permanent magnetic bars (45) are magnetically attracted to each other, and the PL The C controller is electrically connected to the electromagnetic strip (4117) and the electromagnet (49) to form a regulating loop, the PLC controller is electrically connected to the first motor (46) and the second motor (416) to form a control loop, the PLC controller is electrically connected to the upper blower (31) and the lower blower (32) to form a start-stop loop, the PLC controller is electrically connected to the infrared transmitter and the infrared receiver to form a positioning loop, and the PLC controller is electrically connected to the light panel (311) and the photoresistor (312) to form a monitoring loop.

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