Color sorter for refined tea production

Abstract

The invention relates to the technical field of tea processing, in particular to a color sorter for refined tea production, the color sorter comprises a feeding system, an optical detection system, a sorting mechanism and a control unit, the feeding system is provided with a centrifugal dispersion disc which is of a conical spiral structure, and the disc surface of the centrifugal dispersion disc is provided with turbulent flow protrusions; the optical detection system comprises multiple layers of dynamic light source modules; and the sorting mechanism is positioned below the optical detection system and is used for re-sorting the tea leaves. The method has the effects of low impurity residual rate and high superior product rate.

Description

Technical Field

[0001] The present invention relates to the technical field of tea processing, and particularly to a color sorter for refined tea production. Background Art

[0002] In the process of refined tea production, the color sorter is the core equipment for removing impurities such as tea stalks, yellow leaves, insect-eaten leaves, different-color particles and non-tea foreign matters, and it realizes precise sorting based on the color difference of materials. The working principle of the current mainstream color sorter is to identify the color difference between the target object and the background through an optical detection system, and combine a high-speed actuator to remove the impurities to ensure the quality and appearance consistency of the tea.

[0003] The structure of the existing color sorter includes a feeding system, an optical detection system, a sorting mechanism and a control unit. Among them, the feeding system uses a vibrating feeder or a conveyor belt to evenly disperse the tea into a single layer and enter the detection area. The optical detection system consists of a high-resolution CCD / CMOS camera and a multi-band light source to capture the color and texture information on the surface of the tea. The sorting mechanism is usually an array of high-speed air nozzles or a micro manipulator, and blows and removes the impurities according to the detection signal. The control unit integrates image processing algorithms and sorting logics to control the actions of the actuator in real time.

[0004] The tea is evenly transported to the optical detection area through the feeding system. The camera collects the material image under a specific light source. The control unit analyzes the color, shape and brightness characteristics, and the identified impurities trigger the air nozzles at the corresponding positions, blowing them away from the normal tea flow. The sorted pure tea enters the collection bin, and the impurities enter the waste channel.

[0005] The existing color sorter has a high impurity residue rate, a low high-quality product rate and an increased production cost during the refined tea process. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, one of the purposes of the present invention is to provide a color sorter with a low impurity residue rate and a high high-quality product rate during the refined tea process.

[0007] The above application purpose of the present invention is achieved through the following technical solutions: A color sorter for refined tea production, including a feeding system, an optical detection system, a sorting mechanism and a control unit; The feeding system is provided with a centrifugal dispersion disk, which has a conical spiral structure, and the disk surface of the centrifugal dispersion disk is provided with turbulence protrusions; The optical detection system includes a multi-layer dynamic light source module; The sorting mechanism is located below the optical detection system for re-sorting the tea.

[0008] As a further embodiment of a color sorter for refined tea production disclosed in the present invention, the feeding system further includes a vibration unit and a driving member. The vibration unit is installed at the bottom of the centrifugal dispersion disk and is connected to the optical detection system. The driving member is used to drive the centrifugal dispersion disk to vibrate.

[0009] As a further embodiment of a color sorter for refined tea production disclosed in the present invention, the vibration unit includes an outer shell and multiple inner vibration layers; The outer shell is made of a flexible material, and its two ends are respectively connected to the bottom of the centrifugal dispersion disk and the optical detection system; The inner vibration layer includes a partition and a vibration element. Multiple inner vibration layers are separated by the partition, and the vibration element is used to reset the outer shell after compression and extension.

[0010] As a further embodiment of a color sorter for refined tea production disclosed in the present invention, damping balls are connected between the vibration elements between adjacent inner vibration layers.

[0011] As a further embodiment of a color sorter for refined tea production disclosed in the present invention, the optical detection system is alternately composed of an annularly arranged LED light source and a near-infrared light source.

[0012] As a further embodiment of a color sorter for refined tea production disclosed in the present invention, the LED light source and the near-infrared light source are installed through an annular guide rail, and the light irradiation direction forms a 45° angle with the camera.

[0013] As a further embodiment of a color sorter for refined tea production disclosed in the present invention, a high-pressure air nozzle is further provided in the optical detection system, and a conical diversion cavity is provided inside the nozzle of the high-pressure air nozzle.

[0014] As a further embodiment of a color sorter for refined tea production disclosed in the present invention, the sorting mechanism includes a sorting unit. The sorting unit includes a mechanical screen, a vibration motor, and a diversion pipe. The mechanical screen is used to further sort the tea. The output end of the vibration motor is connected to the mechanical screen to drive the mechanical screen to vibrate. The diversion pipe is located below the mechanical screen.

[0015] As a further embodiment of a color sorter for refined tea production disclosed in the present invention, multiple groups of the sorting units can be provided.

[0016] In summary, the present invention includes at least one of the following beneficial technical effects: 1. The conical spiral structure and turbulent flow protrusions of the centrifugal dispersion disk generate a turbulent flow field to achieve the depolymerization of tea lumps, from macroscopic dispersion to interlayer separation and finally monolayer spreading. The synchronously started vibration unit applies anti-phase vibration energy to cancel its resonance effect, ultimately enabling the tea leaves to fall at a uniform speed and form a monolayer distribution, reducing the sorting error caused by tea lumps clustering. 2. The optical detection system alternately irradiates with RGB-W four-color LED light sources and near-infrared LED light sources, and uses a dual verification mechanism of color difference analysis and near-infrared absorption spectrum to identify the quality of tea leaves. The control of the light source module cooperates with adjustable filter plates to adaptively match the light reflection characteristics of different tea leaves. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the overall structure of an embodiment of a color sorter for refined tea production disclosed by the present invention; Figure 2 is a schematic diagram of the internal structure of the feeding system and the optical detection system of an embodiment of a color sorter for refined tea production disclosed by the present invention; Figure 3 is a schematic diagram of the distribution of vibration units of an embodiment of a color sorter for refined tea production disclosed by the present invention; Figure 4 is a schematic diagram of the internal structure of a vibration unit of an embodiment of a color sorter for refined tea production disclosed by the present invention; Figure 5 is a schematic diagram of the structure of a sorting mechanism of an embodiment of a color sorter for refined tea production disclosed by the present invention.

[0018] In the figure, 1, feeding system; 11, centrifugal dispersion disk; 111, turbulent flow protrusion; 12, vibration unit; 121, outer housing; 122, inner vibration layer; 123, partition; 124, vibration element; 125, damping ball; 13, driving member; 2, optical detection system; 21, detection housing; 211, blanking port; 212, impurity material port; 22, dynamic light source module; 23, high-pressure air nozzle; 3, sorting mechanism; 31, sorting unit; 311, mechanical screen; 312, vibration motor; 313, diversion pipe; 4, control unit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following further details the present invention with reference to the accompanying drawings.

[0020] Referring to Figures 1-5 , a color sorter for refined tea production disclosed by the present invention includes a feeding system 1, an optical detection system 2, a sorting mechanism 3 and a control unit 4.

[0021] Among them, the feeding system 1 includes a centrifugal dispersion disk 11, a vibration unit 12 and a driving member 13. Among them, the centrifugal dispersion disk 11 is made of food-grade stainless steel and has a conical spiral involute structure. Its top is provided with a progressive flaring with a diameter of 80-120 mm. The disk surface forms a spiral diversion channel with an inclination angle of 15°-25°. The disk surface of the centrifugal dispersion disk 11 is provided with a number of flow disturbance protrusions 111. The height of the flow disturbance protrusions 111 can be set to 1.5-3 mm, and the distance between adjacent flow disturbance protrusions 111 is controlled within the range of 5-8 mm. Specific adjustments are made according to the actual size of the centrifugal dispersion disk 11 here. The flow disturbance protrusions 111 can first break up the tea agglomerates, facilitate the formation of a single-layer uniform distribution of the tea and at the same time reduce the falling speed of the tea. The vibration unit 12 is installed at the bottom of the centrifugal dispersion disk 11 and is connected to the optical detection system 2. The vibration unit 12 serves as a support member for the centrifugal dispersion disk 11.

[0022] The driving member 13 can be selected as a servo motor, preferably a three-phase servo motor with a rated power of 0.75 kW. Its output end is connected with a wear-resistant alloy steel cam with a nitrided surface through a flange. The outer edge of the cam maintains a dynamic gap of 0.5-1 mm with the side wall of the centrifugal dispersion disk 11. Through the reciprocating motion of the cam lift of 2-5 mm, the centrifugal dispersion disk 11 generates a mechanically vibrating with adjustable amplitude. When the servo motor starts, the centrifugal dispersion disk 11 vibrates under the drive of the cam. The servo motor adopts a closed-loop vector control mode, and the rotational speed is accurately adjusted to the range of 50-300 rpm through a frequency converter.

[0023] Regarding the vibration unit 12, it includes a housing 121 and multiple inner vibration layers 122. The housing 121 is ellipsoidal and is molded from silicone rubber or polyurethane elastomer with a Shore hardness of 40-60A. The wall thickness is controlled within the range of 2-4 mm. Its two ends can be respectively connected to the bottom of the centrifugal dispersion disk 11 and the optical detection system 2 through flanges. The inner vibration layer 122 includes a partition 123 and a vibration element 124. Multiple inner vibration layers 122 are separated by the partition 123. The partition 123 is made of a 304 stainless steel corrugated plate with a thickness of 0.5-1 mm. A honeycomb-shaped through-hole array with a diameter of 3-5 mm can be opened on it to optimize the stress distribution. The vibration element 124 can preferably be realized by a spring assembly, specifically a helical compression spring wound from 60Si2MnA spring wire with a diameter of 0.8-1.2 mm. The pre-compression amount of the spring assembly is set to 20% to 30% of the total stroke, and a reciprocating amplitude of 0.5-3 mm can be generated during operation. The vibration frequency response range is 5-15 Hz. When the housing 121 is compressed by an external excitation, the spring stores energy through elastic deformation; when the external force is removed, the spring releases energy to drive the housing 121 to reset, forming a continuous vibration cycle. To realize the reset of the housing 121 after compression and extension.

[0024] In the illustrated embodiment, there are three groups of inner vibration layers 122. This is only for illustrative purposes and does not specifically limit the number of inner vibration layers 122. The amplitudes of vibration among multiple groups of inner vibration layers 122 will not be exactly the same, so they affect each other to form damping, enabling the vibration unit 12 to generate high-frequency vibration rather than large-amplitude vibration, thereby increasing the vibration frequency of the centrifugal dispersion disc 11 and reducing the sorting error formed in the optical detection system 2 due to uneven tea leaf dispersion. Actually, when the vibration unit 12 is in the working state, it can generate high-frequency micro-vibrations with a frequency of 100 - 500 Hz and an amplitude of <0.5 mm. This design improves the evenness of tea leaf dispersion to over 95% and effectively controls the optical detection error rate within 0.5‰.

[0025] Furthermore, damping balls 125 are connected between the vibration elements 124 of adjacent inner vibration layers 122. The damping balls 125 penetrate the aforementioned partition plate 123. Through the damping balls 125, it is difficult for the vibration elements 124 to form resonance. The structure is simple but makes the high-frequency vibration of the vibration unit 12 more stable.

[0026] The vibration units 12 are arranged in multiple numbers and are arrayed along the bottom of the centrifugal dispersion disc 11. While serving as the support members of the centrifugal dispersion disc 11, they realize the high-frequency vibration of the centrifugal dispersion disc 11.

[0027] The optical detection system 2 includes a detection housing 21 in the shape of a rectangular parallelepiped. The detection housing 21 is provided with a blanking port 211 and an impurity material port 212. A multi-layer dynamic light source module 22 is installed on the inner wall of the detection housing 21. The optical detection system 2 is alternately composed of an RGB-W four-color LED light source and a near-infrared light source arranged in a ring. Among them, the RGB-W four-color LED selects a surface-mounted light source with a color temperature of 5500K ± 300K and a color rendering index > 90, and the single-chip power is 1.5 - 3W. The near-infrared LED selects a diffused device with a peak wavelength of 850nm ± 10nm and a radiation intensity of 50 - 100mW / sr. A rotatable filter with a diameter of 600mm is coaxially assembled on the outer edge of the light source array. The filter substrate is an optical-grade borosilicate glass with a thickness of 2mm, and 12 layers of interference films are coated on the surface to form a band-pass filtering characteristic of 450 - 950nm.

[0028] A rotatable filter can be added to the periphery of the dynamic light source module 22 to adapt to the spectral requirements of different tea leaf types. The LED light source and the near-infrared light source are installed through a ring-shaped guide rail. The guide rail is internally equipped with a stepping motor to drive the light source to rotate horizontally. The rotation angle range is 0 - 180°. The illumination direction of the light source forms a 45° angle with the camera. This geometric configuration is optimized through ray tracing simulation to ensure that the illuminance uniformity on the tea leaf surface > 95%. The light source module supports PWM dimming control, and the brightness adjustment range is adjustable from 10% to 100%, and the pulse frequency can be configured from 1 - 10kHz.

[0029] As a further embodiment of the present invention, a dust-proof component may be provided outside the optical detection system 2, including a compressed air curtain generator surrounding the detection area and a transparent anti-static resin cover. The nozzle direction of the air curtain generator is inclined downward by 30°, forming an air flow barrier for isolating tea dust.

[0030] A high-pressure air flow nozzle 23 is further provided inside the optical detection system 2. The high-pressure air flow nozzle 23 adopts a modular quick-release design. A conical diversion cavity is provided inside the high-pressure air flow nozzle 23. A piezoelectric ceramic sheet is installed at the end of the cavity for adjusting the air flow pulse frequency according to a control signal.

[0031] The sorting mechanism 3 is located below the optical detection system for re-sorting the tea. The sorting mechanism 3 includes a sorting unit 31. The sorting unit 31 includes a mechanical sieve 311, a vibration motor 312, and a diversion pipe 313. Among them, the mechanical sieve 311 is used for re-sorting the tea. The output end of the vibration motor 312 is connected to the mechanical sieve 311 to drive the mechanical sieve 311 to vibrate. The diversion pipe 313 is located below the mechanical sieve 311.

[0032] It should be understood that multiple groups of sorting units 31 can be set. The mesh sizes of the mechanical sieves 311 of each sorting unit 31 are designed to decrease in gradient. The aperture difference between levels is controlled within 0.5 - 1.5 mm. Through multi-stage collaborative screening, the sorting error rate can be reduced to less than 0.3%. Qualified tea is transported to the automatic packaging machine through the diversion pipe 313, and the flow rate is controlled at 1 - 2 m / s; unqualified tea enters the circulation treatment bin through the defective product collection channel, and its collection efficiency > 98%. The control unit 4 synchronously regulates the phase difference and amplitude of each vibration motor 312 through the bus, so that adjacent sorting units 31 generate a differential frequency vibration of 5 - 15 Hz, effectively eliminating the phenomenon of material accumulation.

[0033] The implementation principle of this embodiment is as follows: Through the conical spiral structure and the turbulent flow protrusions 111 of the centrifugal dispersion disk 11, a turbulent flow field is generated. When the tea enters at a flow rate of 0.8 - 1.5 kg / min, the disaggregation of tea lumps is realized, from macroscopic dispersion to interlayer separation to finally single-layer spreading. The synchronously started vibration unit 12 vibrates at a high frequency and small amplitude of 100 - 500 Hz, applying anti-phase vibration energy to cancel its resonance effect. Finally, the tea falls at a uniform speed and forms a single-layer distribution, reducing the sorting error caused by tea clumping.

[0034] The optical detection system 2 alternately irradiates with RGB-W four-color LEDs and near-infrared LEDs, and uses a dual verification mechanism to identify the quality of tea by color difference analysis (defining ΔE>3.0 as defective products) and near-infrared absorption spectra (defining characteristic peaks at 1300-2500 nm). The rotation control of the light source module is combined with an adjustable filter to adaptively match the light reflection characteristics of different teas, such as the main reflection band of green tea at 450-550 nm and that of black tea at 600-700 nm. The 45° incident angle design makes the ratio of the diffuse reflection light intensity to the specular reflection light intensity captured by the camera stable in the range of 0.75-1.25, eliminating the interference of glossiness.

[0035] The control unit 4 constructs a multi-dimensional control model through vibration spectrum analysis, optical feature extraction, and air flow pressure feedback. The ARM processor calculates the correlation function of vibration parameters, optical parameters, and sorting parameters in real time, and realizes a system response delay of <1 ms through FPGA hardware acceleration, so that the overall sorting accuracy reaches 99.7%±0.15%.

[0036] The embodiments of this specific implementation manner are all preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A color sorter for refined tea production, comprising a feeding system (1), an optical detection system (2), a sorting mechanism (3) and a control unit, characterized in that: The feeding system (1) is provided with a centrifugal dispersion disk (11), which has a conical spiral structure, and the disk surface of the centrifugal dispersion disk (11) is provided with turbulence protrusions (111); The optical detection system (2) includes a multi-layer dynamic light source module (22); The sorting mechanism (3) is located below the optical detection system (2) for re-sorting the tea.

2. The color sorter for refined tea production according to claim 1, characterized in that: The feeding system (1) further includes a vibration unit (12) and a driving member (13). The vibration unit (12) is installed at the bottom of the centrifugal dispersion disk (11) and is connected to the optical detection system (2). The driving member (13) is used to drive the centrifugal dispersion disk (11) to vibrate.

3. The color sorter for refined tea production according to claim 2, characterized in that: The vibration unit (12) includes an outer shell (121) and multiple groups of inner vibration layers (122); The outer shell (121) is made of a flexible material, and its two ends are respectively connected to the bottom of the centrifugal dispersion disk (11) and the optical detection system (2); The inner vibration layer (122) includes a partition plate (123) and a vibration element (124). Multiple groups of inner vibration layers (122) are separated by the partition plate (123), and the vibration element (124) is used to realize the reset of the outer shell (121) after compression and expansion.

4. The color sorter for refined tea production according to claim 3, wherein: A damping ball (125) is connected between the vibration elements (124) between adjacent inner vibration layers (122).

5. A color sorter for refined tea production according to claim 1, characterized in that: The optical detection system (2) is alternately composed of an annularly arranged LED light source and a near-infrared light source.

6. A color sorter for refined tea production according to claim 5, characterized in that: The LED light source and the near-infrared light source are installed through an annular guide rail, and the light irradiation direction forms a 45° angle with the camera.

7. A color sorter for refined tea production according to claim 5, characterized in that: A high-pressure air nozzle (23) is further arranged in the optical detection system (2), and a conical diversion cavity is arranged inside the nozzle of the high-pressure air nozzle (23).

8. A color sorter for refined tea production according to any one of claims 1-7, characterized in that: The sorting mechanism (3) includes a sorting unit (31). The sorting unit (31) includes a mechanical screen (311), a vibration motor (312) and a diversion pipe (313). The mechanical screen (311) is used to re-sort the tea. The output end of the vibration motor (312) is connected to the mechanical screen (311) to drive the mechanical screen (311) to vibrate. The diversion pipe (313) is located below the mechanical screen (311).

9. A color sorter for refined tea production according to claim 8, characterized in that: The sorting unit (31) can be set in multiple groups.

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