Single screw grinding apparatus

Abstract

The application discloses a single-screw grinding equipment, and belongs to a single-screw grinding equipment for recycling waste plastics and waste rubbers, which mainly comprises a machine cylinder, a feeding cylinder, an equidistant variable-diameter screw, a vortex pulverizing grinding disc, an electromagnetic heater, a temperature sensor and a pressure sensor. The single-screw grinding equipment integrates material conveying, pressure boosting pre-crushing and vortex grinding, can continuously grind the waste plastics and the waste rubbers, has the advantages of compact structure, uniform grinding, accurate temperature control and lower energy consumption, and improves the grinding and recycling efficiency of the waste high polymer materials.

Description

Technical Field

[0001] This invention relates to equipment for recycling and processing waste polymer materials, specifically to a single-screw grinding machine for recycling waste plastics and waste rubber. Background Technology

[0002] Currently, plastics and rubber are widely used in packaging, construction, automobiles, electronics, and daily consumer goods due to their advantages such as light weight, high strength, ease of processing, and low cost, resulting in huge consumption volumes. However, with large-scale production and consumption, the amount of waste plastics and rubber generated is increasing year by year. Because these waste polymer materials are difficult to degrade in the natural environment, large-scale accumulation will occupy land resources, causing soil and water pollution, posing a significant challenge to the ecological environment and sustainable resource utilization. Therefore, the efficient recycling and reuse of waste plastics and rubber has become an urgent problem to be solved in the fields of resource recycling and environmental protection. Before recycling, waste plastics and rubber usually need to undergo crushing and grinding processes to be processed into particle sizes suitable for subsequent processing. Due to the complex composition of waste plastics and rubber, especially waste rubber which has high elasticity, high toughness, and is not easy to directly crush, high requirements are placed on the structure and process of grinding equipment.

[0003] Currently, the main grinding methods used for recycling waste plastics and waste rubber include single-screw extruders, mechanical grinding mills, vortex pulverizers, and screw-grinding disc combination equipment. Among them, single-screw extruders mainly rely on heating and plasticizing and screw conveying, with relatively weak mechanical compression and crushing effects. When processing highly elastic waste rubber, they are prone to slippage, material backflow, and blockage. Although mechanical grinding mills and vortex pulverizers can perform shearing and grinding using moving and fixed blades, they usually require pre-crushing, making it difficult to complete continuous conveying, heating, softening, and grinding within the same equipment. Furthermore, they are prone to blade sticking, temperature rise, and uneven particle size when processing highly elastic materials. Although screw-grinding disc combination equipment attempts continuous grinding, the screws are mostly ordinary constant-diameter screws or only perform partial compression, resulting in a limited compression ratio. It is difficult to form sufficient extrusion pressure and pre-crushing before the material enters the grinding disc. At the same time, the fixed and moving blades of the grinding disc have simple structures, with the moving blades mostly being fixed or integral, making replacement inconvenient after wear. The working surface of the moving blades does not match the arc surface of the inner wall of the barrel well, leading to uneven grinding gaps. In addition, existing equipment generally lacks closed-loop temperature control and screw end pressure detection, making it difficult to adapt to different material characteristics and prevent overload. Overall, it suffers from problems such as fragmented processes, poor adaptability to highly elastic materials, and insufficient grinding efficiency and stability. Summary of the Invention

[0004] To address the aforementioned problems, the purpose of this invention is to provide a single-screw grinding device.

[0005] To achieve the objective of this invention, this invention provides a single-screw grinding device, characterized in that it includes a barrel, the upper part of which has a feed inlet connected to a feeding cylinder, a variable-diameter screw with equal pitch inside the barrel, the head rotating shaft of the variable-diameter screw being connected to a motor, the tail of the variable-diameter screw being connected to the rotating disk of a vortex pulverizer, and the lower part of the vortex pulverizer being connected to a discharge port.

[0006] Preferably, the barrel located at the equidistant variable diameter screw section is equipped with an electromagnetic heater and a temperature sensor, and the barrel located at the end of the equidistant variable diameter screw section is equipped with a pressure sensor. The electromagnetic heater is used for temperature control, the temperature sensor is responsible for detecting the temperature of the equidistant variable diameter screw section and transmitting the detected temperature signal to the controller. The controller adjusts the temperature by controlling the working state of the electromagnetic heater according to the set temperature value and the actual detected temperature difference. The pressure sensor is used to measure the pressure of the material being squeezed.

[0007] Preferably, the pitch of the equal-pitch variable-diameter screw is equal, and the screw diameter of the equal-pitch variable-diameter screw gradually increases from the end near the feed inlet of the feed cylinder to the end near the rotating disk of the vortex pulverizer. The gap between the screw and the inner wall of the cylinder gradually decreases, and the minimum gap is located at 3 / 4 of the distance from the discharge port. This can reduce the excessive load on the motor and reduce the probability of shutdown. In addition, it can make the material loosen due to elastic deformation and defects, making it easier to pulverize in the vortex pulverizer.

[0008] Preferably, the vortex pulverizer includes a fixed blade, a moving blade, and a rotating disk. The rotating disk, located in the tail of the barrel, is fixedly connected to the tail of an equidistant variable-diameter screw. The moving blades are circumferentially distributed on the rotating disk located in the tail of the barrel, and the fixed blades are arranged radially along the inner wall of the tail of the barrel.

[0009] Preferably, the working surface of the moving blade is the arc surface of the inner wall of the barrel.

[0010] Preferably, the moving blade is detachably connected to the rotating disk.

[0011] The beneficial effects of this invention are as follows: feeding, conveying, heating and softening, pressurizing and pre-crushing, and vortex grinding are integrated into a single barrel for continuous operation, eliminating the need for transfer between multiple machines, simplifying the recycling process of waste plastics and waste rubber, and reducing land occupation and energy consumption. The screw adopts a variable diameter structure with a constant pitch and gradually increasing diameter, so that the material is subjected to gradually increasing extrusion pressure during conveying, which can pre-crush and pressurize waste plastics and waste rubber, reduce slippage, backflow, and blockage of highly elastic materials, and improve the density and crushing degree of the material before entering the grinding disc. The moving blades of the rear vortex grinding disc are evenly distributed circumferentially on the rotating disc, and the fixed blades are arranged radially along the inner wall of the barrel, forming a strong vortex shearing and grinding effect. The working surface of the moving blade adopts an arc surface that matches the inner wall of the barrel, which helps to maintain a uniform grinding gap, making the material more fully ground and the particle size more uniform. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the single-screw grinding device of the present invention.

[0013] Figure 2 This is a schematic diagram of an eddy current pulverizer.

[0014] In the diagram: 1. Motor; 2. Feeding cylinder; 3. Machine barrel; 31. Electromagnetic heater; 32. Equal pitch variable diameter screw; 4. Pressure sensor; 5. Temperature sensor; 6. Vortex pulverizer; 61. Fixed blade; 62. Moving blade; 63. Rotary disc; 7. Discharge port. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0016] like Figure 1 and Figure 2 As shown, the single-screw grinding equipment of the present invention includes a motor 1, a feed cylinder 2, a barrel 3, an electromagnetic heater 31, an equidistant variable-diameter screw 32, a pressure sensor 4, a temperature sensor 5, an eddy current pulverizer 6, and a discharge port 7. The upper part of the barrel 3 is provided with a feed inlet, and the feed cylinder 2 is connected to the feed inlet. The equidistant variable-diameter screw 32 is installed inside the barrel 3, and its head rotating shaft is connected to the motor 1, driving it to rotate. The tail of the equidistant variable-diameter screw 32 is connected to the rotating disk 63 of the eddy current pulverizer 6 located in the tail of the barrel, driving the rotating disk 63 to rotate synchronously. The lower part of the eddy current pulverizer 6 is connected to the discharge port 7.

[0017] The pitch of the equal-pitch variable-diameter screw 32 is equal, but the screw diameter gradually increases from the end near the feed inlet of the feed cylinder 2 to the end near the rotating disk 63 of the vortex pulverizer 6. This gradually reduces the space occupied by the material during conveying and subjecting it to gradually increasing extrusion pressure. The gap between the screw and the inner wall of the barrel 3 gradually decreases, with the minimum gap located at approximately 3 / 4 of the screw length from the discharge port 7. This avoids excessive extrusion pressure at the screw end, which could lead to excessive motor load and shutdown, and also allows the material to undergo elastic deformation and relaxation after maximum compression, thus preventing defects and facilitating subsequent vortex pulverization. An electromagnetic heater 31 and a temperature sensor 5 are installed inside the barrel 3 located outside the equal-pitch variable-diameter screw section. Temperature sensor 5 detects the temperature of the material in this section and transmits the temperature signal to the controller. The controller is a product that can be implemented by general technicians, such as a microcontroller. The control software built into the microcontroller is also achievable by general technicians. The controller compares the actual detected temperature with the set temperature. When the temperature detected by temperature sensor 5 is lower than the set temperature, it controls the electromagnetic heater 31 to work and heat up. When the set temperature is reached, the heating is reduced or stopped, thereby realizing closed-loop temperature regulation, so that the material reaches a softened state suitable for grinding. After the material is softened by heat, it is easier to deform under the extrusion of the variable diameter screw. After the pressure is released, it relaxes, which is conducive to the formation of defects such as cracks and notches. A pressure sensor 4 is installed in the barrel at the end of the equidistant variable diameter screw 32 to detect the extrusion pressure on the material before entering the vortex pulverizer 6, so as to adjust the feed rate and screw speed and prevent overload.

[0018] like Figure 2 As shown, the vortex pulverizer 6 includes a fixed blade 61, a moving blade 62, a rotating disk 63, and a discharge port 7. The vortex pulverizer 6 is located inside a barrel 3 at its tail end; that is, the outer shell of the vortex pulverizer 6 is the barrel 3. The moving blades 62 are circumferentially evenly distributed on the rotating disk 63 located at the tail end of the barrel and can rotate with the rotating disk 63. The fixed blades 61 are radially arranged along the inner wall of the tail end of the vortex pulverizer 6, i.e., fixed to the inner wall of the tail end of the barrel and arranged radially. The working surface of the moving blades 62 is an arc surface that mates with the inner wall of the tail end of the barrel, creating a uniform grinding gap between the moving blades 62 and the inner wall of the tail end of the barrel, and between the moving blades 62 and the fixed blades 61, thus improving grinding uniformity. The moving blades 62 are fixed to the rotating disk 63 by detachable connections such as bolts. When the moving blades 62 wear out, they can be disassembled and replaced individually without replacing the entire rotating disk 63.

[0019] During operation, waste plastics and / or waste rubber enter the barrel 3 through the feeding cylinder 2, and the motor 1 drives the equidistant variable diameter screw 32 to rotate. The material is conveyed forward under the push of the equidistant variable diameter screw 32, and simultaneously experiences increasing compressive force due to the gradually increasing screw diameter. It softens under the heating effect of the electromagnetic heater 31, and some of the material is pre-crushed. After being detected by the end pressure sensor 4, the material enters the vortex pulverizer 6. The rotating disk 63 of the vortex pulverizer 6, located at the tail of the barrel, drives the moving blades 62 to rotate, generating shearing, impact, and grinding actions with the fixed blades 61 on the inner wall of the barrel tail, further grinding the material into particles or powder of the required particle size, and finally discharging it from the discharge port 7.

[0020] The above-described specific embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention. Therefore, any changes and modifications made to the embodiments of the present invention based on the innovative concept of the present invention, or equivalent structural transformations made using the content of the present invention's specification and drawings, directly or indirectly applying the above technical solutions to other related technical fields, are all included within the scope of protection of the patent application of the present invention.

Claims

1. A single-screw grinding device, characterized in that, The device includes a barrel, with an inlet at the top of the barrel connected to a feeding cylinder. Inside the barrel is a variable-diameter screw with equal spacing. The rotating shaft at the head of the variable-diameter screw is connected to a motor exposed at one end of the barrel head. The tail of the variable-diameter screw is connected to a rotating disk of a vortex pulverizer located at the tail of the barrel. The lower part of the vortex pulverizer is connected to a discharge port.

2. The single-screw grinding equipment according to claim 1, characterized in that, The barrel located at the equidistant variable diameter screw section is equipped with an electromagnetic heater and a temperature sensor, and the barrel located at the end of the equidistant variable diameter screw section is equipped with a pressure sensor. The electromagnetic heater is used for temperature control, and the temperature sensor is responsible for detecting the temperature of the equidistant variable diameter screw section and transmitting the detected temperature signal to the controller. The controller adjusts the temperature by controlling the working state of the electromagnetic heater according to the set temperature value and the actual detected temperature difference. The pressure sensor is used to measure the pressure of the material being squeezed.

3. The single-screw grinding equipment according to claim 1, characterized in that, The equal-pitch variable-diameter screws have equal pitches, and their diameters gradually increase from the feed inlet end near the feed cylinder to the rotating disc end near the vortex pulverizer. The gap between the screw and the inner wall of the cylinder gradually decreases, with the minimum gap located at 3 / 4 of the distance from the discharge port. This reduces excessive motor load and the probability of machine shutdown. In addition, it can loosen the material due to elastic deformation, making it easier to pulverize in the vortex pulverizer.

4. The single-screw grinding equipment according to any one of claims 1-3, characterized in that, The vortex pulverizer includes a fixed blade, a moving blade, and a rotating disk. The rotating disk, located at the tail of the barrel, is fixedly connected to the tail of an equidistant variable-diameter screw. The moving blades are circumferentially distributed on the rotating disk located at the tail of the barrel, and the fixed blades are arranged radially along the inner wall of the tail of the barrel.

5. The single-screw grinding equipment according to claim 4, characterized in that, The working surface of the moving blade is the arc surface of the inner wall of the barrel.

6. The single-screw grinding equipment according to claim 4, characterized in that, The moving blade is detachably connected to the rotating disk.

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