A color sorter for refined tea production

Abstract

The present invention relates to the technical field of tea processing, and 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 includes a centrifugal dispersing disc with a conical spiral structure and a surface provided with flow-disrupting protrusions. The optical detection system includes a multi-layer dynamic light source module. The sorting mechanism is located below the optical detection system and is used to further sort the tea leaves. The present invention achieves low impurity residue rates and a high rate of high-quality tea leaves.

Description

Technical Field

[0001] The invention relates to the technical field of tea processing, in particular to a color sorter used for refined tea production. Background Art

[0002] In the tea refining process, color sorters are essential equipment for removing impurities such as tea stems, yellow leaves, insect-damaged leaves, off-color particles, and non-tea foreign matter. They achieve precise sorting based on color differences. Currently, mainstream color sorters use optical detection systems to identify the color difference between the target object and the background, and then combine high-speed actuators to remove impurities, ensuring consistent tea quality and appearance.

[0003] The structure of an existing color sorter consists of a feeding system, an optical inspection system, a sorting mechanism, and a control unit. The feeding system uses a vibrating feeder or conveyor belt to evenly disperse the tea leaves into a single layer before they enter the inspection area. The optical inspection system consists of a high-resolution CCD / CMOS camera and a multi-band light source to capture the surface color and texture of the tea leaves. The sorting mechanism typically uses an array of high-speed airflow nozzles or a micro-robotic arm to remove impurities based on detection signals. The control unit integrates image processing algorithms and sorting logic to control the actuators in real time.

[0004] Tea leaves are evenly transported to the optical inspection area through the feeding system. The camera collects material images under a specific light source, and the control unit analyzes the color, shape and brightness characteristics. The identified impurities trigger the air flow nozzles at the corresponding position to blow them away from the normal tea flow. The pure tea leaves after sorting enter the collection bin, and the impurities enter the waste channel.

[0005] The existing color sorting machines have the problems of high impurity residue rate, low quality rate and increased production costs during the tea refining process. Summary of the Invention

[0006] In view of the shortcomings of the prior art, one of the purposes of the present invention is to provide a color sorter with low impurity residual rate and high quality rate in the tea refining process.

[0007] The above-mentioned application objectives of the present invention are achieved through the following technical solutions:

[0008] A color sorter for refined tea production, comprising a feeding system, an optical detection system, a sorting mechanism and a control unit;

[0009] The feeding system is provided with a centrifugal dispersing disk, which is a conical spiral structure, and the disk surface of the centrifugal dispersing disk is provided with flow-disturbing protrusions;

[0010] The optical detection system includes a multi-layer dynamic light source module;

[0011] The sorting mechanism is located below the optical detection system and is used to re-sort the tea leaves.

[0012] As a further embodiment of the color sorter for refined tea production disclosed in the present invention, the feeding system also 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.

[0013] As a further embodiment of the color sorter for refined tea production disclosed in the present invention, the vibration unit includes an outer shell and multiple groups of inner vibration layers;

[0014] 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;

[0015] The inner vibration layer includes a partition and a vibration element. Multiple groups of inner vibration layers are separated by the partition. The vibration element is used to achieve the restoration of the outer shell after compression and extension.

[0016] As a further embodiment of the color sorter for refined tea production disclosed in the present invention, damping balls are connected between the vibration elements between adjacent inner vibration layers.

[0017] As a further embodiment of the color sorter for refined tea production disclosed in the present invention, the optical detection system is composed of an LED light source and a near-infrared light source arranged alternately in a ring.

[0018] As a further embodiment of the color sorter for refined tea production disclosed in the present invention, the LED light source and the near-infrared light source are installed through a ring guide rail, and the irradiation direction of the light source forms an angle of 45° with the camera.

[0019] As a further embodiment of the color sorter for refined tea production disclosed in the present invention, a high-pressure airflow nozzle is further provided in the optical detection system, and a conical guide cavity is provided inside the nozzle of the high-pressure airflow nozzle.

[0020] As a further embodiment of a color sorter for refined tea production disclosed in the present invention, the sorting mechanism includes a sorting unit, which includes a mechanical screen, a vibration motor and a guide pipe. The mechanical screen is used to re-sort the tea leaves. The output end of the vibration motor is connected to the mechanical screen to drive the mechanical screen to vibrate, and the guide pipe is located below the mechanical screen.

[0021] As a further embodiment of the color sorter for refined tea production disclosed in the present invention, the sorting units can be arranged into multiple groups.

[0022] In summary, the present invention includes at least one of the following beneficial technical effects:

[0023] 1. The conical spiral structure and turbulent protrusions of the centrifugal dispersing disc generate a turbulent flow field, achieving the deagglomeration of tea clumps, from macroscopic dispersion to interlayer separation and finally single-layer spreading. The synchronously activated vibration unit applies anti-phase vibration energy to offset the resonance effect, ultimately causing the tea leaves to fall at a uniform speed and form a single-layer distribution, reducing the sorting error caused by tea clumping;

[0024] 2. The optical detection system uses alternating RGB-W four-color LED light sources and near-infrared LED light sources to identify tea quality through a dual verification mechanism using color difference analysis and near-infrared absorption spectra. The control of the light source module is combined with an adjustable filter to adaptively match the light reflection characteristics of different teas. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the overall structure of an embodiment of a color sorter for refined tea production disclosed in the present invention;

[0026] Figure 2 This is a schematic diagram of the internal structure of a feeding system and an optical detection system of an embodiment of a color sorter for refined tea production disclosed in the present invention;

[0027] Figure 3 This is a schematic diagram of the distribution of vibration units of an embodiment of a color sorter for refined tea production disclosed in the present invention;

[0028] Figure 4 This is a schematic diagram of the internal structure of a vibration unit of an embodiment of a color sorter for refined tea production disclosed in the present invention;

[0029] Figure 5 The invention discloses a structural schematic diagram of a sorting mechanism of a color sorter for refined tea production in accordance with one embodiment of the present invention.

[0030] In the figure, 1, feeding system; 11, centrifugal dispersion disc; 111, spoiler protrusion; 12, vibration unit; 121, outer shell; 122, inner vibration layer; 123, partition; 124, vibration element; 125, damping ball; 13, driving member;

[0031] 2. Optical detection system; 21. Detection housing; 211. Blanking port; 212. Impurity port; 22. Dynamic light source module; 23. High-pressure airflow nozzle;

[0032] 3. Sorting mechanism; 31. Sorting unit; 311. Mechanical screen; 312. Vibrating motor; 313. Flow guide pipe;

[0033] 4. Control unit. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below with reference to the accompanying drawings.

[0035] Reference Figure 1-5 , is a color sorter for refined tea production disclosed in the present invention, comprising a feeding system 1, an optical detection system 2, a sorting mechanism 3 and a control unit 4.

[0036] The feeding system 1 includes a centrifugal dispersing disc 11, a vibration unit 12, and a drive element 13. The centrifugal dispersing disc 11 is a conical spiral involute structure made of food-grade stainless steel. Its top is provided with a progressive flare with a diameter of 80-120 mm. The disc surface is inclined at a 15-25° angle to form a spiral flow guide channel. The disc surface of the centrifugal dispersing disc 11 is provided with several flow-interference protrusions 111. The height of the flow-interference protrusions 111 can be set to 1.5-3 mm, and the spacing between adjacent flow-interference protrusions 111 is controlled within the range of 5-8 mm. This is adjusted based on the actual size of the centrifugal dispersing disc 11. The flow-interference protrusions 111 can first break up tea clumps, facilitating the formation of a single layer of evenly distributed tea leaves while also reducing the falling speed of the tea leaves. The vibration unit 12 is mounted at the bottom of the centrifugal dispersing disc 11 and is connected to the optical detection system 2. The vibration unit 12 serves as a support member for the centrifugal dispersing disc 11.

[0037] The driving member 13 can be selected as a servo motor, preferably a three-phase servo motor with a rated power of 0.75kW. The output end of the servo motor is connected to a wear-resistant alloy steel cam with surface nitriding treatment through a flange. The outer edge of the cam maintains a dynamic gap of 0.5-1mm with the side wall of the centrifugal dispersion disk 11. The reciprocating motion of the cam lift of 2-5mm makes the centrifugal dispersion disk 11 generate mechanical vibration with adjustable amplitude. When the servo motor is started, the centrifugal dispersion disk 11 vibrates under the drive of the cam. The servo motor adopts closed-loop vector control, and the speed is accurately adjusted to the range of 50-300rpm by the frequency converter.

[0038] Regarding the vibration unit 12, it includes an outer shell 121 and multiple groups of inner vibration layers 122. The outer shell 121 is ellipsoidal and is molded with silicone rubber or polyurethane elastomer with a Shore hardness of 40-60A. The wall thickness is controlled within the range of 2-4mm. Its two ends can be connected to the bottom of the centrifugal dispersion disk 11 and the optical detection system 2 respectively through flanges. The inner vibration layer 122 includes a partition 123 and a vibration element 124. Multiple groups of inner vibration layers 122 are separated by partitions 123. The partitions 123 are made of 304 stainless steel corrugated plates with a thickness of 0.5-1mm. A honeycomb through-hole array with a diameter of 3-5mm can be opened on it to optimize stress distribution. The vibration element 124 can preferably be implemented as a spring assembly, specifically a helical compression spring wound with 60Si2MnA spring steel wire with a diameter of 0.8-1.2mm. The pre-compression amount of the spring assembly is set to 20% to 30% of the total stroke. During operation, it can generate a reciprocating amplitude of 0.5-3mm and a vibration frequency response range of 5-15Hz. When the outer shell 121 is compressed by external excitation, the spring stores energy through elastic deformation. When the external force is removed, the spring releases energy and drives the outer shell 121 to reset, forming a continuous vibration cycle. This is used to achieve the reset of the outer shell 121 after compression and extension.

[0039] The illustrated embodiment shows three groups of inner vibration layers 122. This is merely an example and does not impose a specific limit on the number of inner vibration layers 122. The vibration amplitudes of multiple groups of inner vibration layers 122 may vary, thus interfering with each other and creating damping. This results in the vibration unit 12 generating high-frequency vibrations rather than large-amplitude vibrations, thereby increasing the vibration frequency of the centrifugal dispersion disc 11 and reducing sorting errors in the optical inspection system 2 caused by uneven tea leaf dispersion. In practice, the vibration unit 12 generates high-frequency micro-vibrations with a frequency of 100-500 Hz and an amplitude of less than 0.5 mm when operating. This design improves tea leaf dispersion uniformity to over 95%, effectively controlling the optical inspection error rate to less than 0.5‰.

[0040] Furthermore, damping balls 125 are connected between the vibration elements 124 between adjacent inner vibration layers 122. The damping balls 125 pass through the aforementioned partition 123. The damping balls 125 make it 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.

[0041] The vibration units 12 are provided in plurality and distributed in an array along the bottom of the centrifugal dispersing disk 11 , serving as support members of the centrifugal dispersing disk 11 while achieving high-frequency vibration of the centrifugal dispersing disk 11 .

[0042] The optical detection system 2 comprises a rectangular detection housing 21, which is provided with a blanking port 211 and an impurity discharge port 212. A multi-layer dynamic light source module 22 is mounted on the inner wall of the detection housing 21. The optical detection system 2 is composed of a circular array of RGB-W four-color LED light sources alternating with near-infrared light sources. The RGB-W four-color LEDs are surface-mount light sources with a color temperature of 5500K ± 300K, a color rendering index greater than 90, and a power of 1.5-3W per light source. The near-infrared LEDs are diffused devices 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 mounted on the outer edge of the light source array. The filter substrate is 2mm thick, optical-grade borosilicate glass, coated with 12 layers of interference film to create a 450-950nm bandpass filter.

[0043] The dynamic light source module 22 can be equipped with a rotatable filter to adapt to the spectral requirements of different tea varieties. The LED and near-infrared light sources are mounted on a circular guide rail. A built-in stepper motor drives the light source's horizontal rotation within a range of 0-180°, with the light source oriented at a 45° angle to the camera. This geometry, optimized through ray tracing simulation, ensures an illumination uniformity of >95% on the tea surface. The light source module supports PWM dimming control, with a brightness adjustment range of 10% to 100% and a configurable pulse frequency of 1-10kHz.

[0044] As a further embodiment of the present invention, a dustproof component can be provided on the periphery of the optical detection system 2, including a compressed air curtain generator surrounding the detection area and a transparent antistatic resin cover. The nozzle of the air curtain generator is tilted downward by 30° to form an airflow barrier to isolate tea dust.

[0045] The optical detection system 2 also includes a high-pressure airflow nozzle 23. This nozzle features a modular, quick-release design and contains a tapered flow guide cavity. A piezoelectric ceramic disc is mounted at the end of the cavity to adjust the airflow pulse frequency based on a control signal.

[0046] The sorting mechanism 3, located below the tea detection system, is used to further sort the tea leaves. It includes a sorting unit 31, which includes a mechanical screen 311, a vibration motor 312, and a flow guide 313. The mechanical screen 311 is used to further sort the tea leaves. The output end of the vibration motor 312 is connected to the mechanical screen 311 to drive it to vibrate. The flow guide 313 is located below the mechanical screen 311.

[0047] It should be understood that the sorting units 31 can be arranged into multiple groups, and the mesh size of the mechanical screen 311 of each sorting unit 31 is designed in a gradient decreasing manner, and the aperture difference between stages is controlled at 0.5-1.5mm. The sorting error rate can be reduced to below 0.3% through multi-stage collaborative screening. Qualified tea leaves are transported to the automatic packaging machine through the guide pipe 313, and the flow rate is controlled at 1-2m / s; unqualified tea leaves enter the recycling processing bin through the defective product collection channel, and its collection efficiency is greater than 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 difference frequency vibration of 5-15Hz, effectively eliminating the phenomenon of material accumulation.

[0048] The implementation principle of this embodiment is:

[0049] The conical spiral structure and the flow-disturbing protrusions 111 of the centrifugal dispersing disk 11 generate a turbulent flow field. When tea leaves enter at a flow rate of 0.8-1.5 kg / min, tea clumps are disaggregated, from macroscopic dispersion to interlayer separation to final single-layer spreading. The synchronously started vibration unit 12 vibrates at a high frequency of 100-500 Hz with a slight amplitude, applying anti-phase vibration energy to offset its resonance effect, ultimately causing the tea leaves to fall at a uniform speed and form a single-layer distribution, reducing the sorting error caused by tea clumping.

[0050] Optical inspection system 2 utilizes alternating illumination from RGB-W four-color LEDs and near-infrared LEDs. This dual verification mechanism identifies tea quality through color difference analysis (e.g., defining an abnormal product as having a ΔE greater than 3.0) and near-infrared absorption spectroscopy (e.g., defining a characteristic peak between 1300-2500nm). The light source module's rotational control, combined with an adjustable filter, adaptively matches the light reflection characteristics of different teas, such as green tea's primary reflection wavelength of 450-550nm and black tea's 600-700nm. The 45° angle of incidence ensures a stable ratio of diffuse to specular light intensity captured by the camera within a range of 0.75-1.25, eliminating gloss interference.

[0051] Control unit 4 builds a multidimensional control model through vibration spectrum analysis, optical feature extraction, and airflow pressure feedback. An ARM processor calculates the correlation function between vibration parameters, optical parameters, and sorting parameters in real time. FPGA hardware acceleration achieves a system response delay of less than 1ms, resulting in an overall sorting accuracy of 99.7% ± 0.15%.

[0052] The embodiments of this specific implementation method are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection 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 dispersing disk (11) having a conical spiral structure, and the disk surface of the centrifugal dispersing disk (11) is provided with a flow-disturbing protrusion (111); The optical detection system (2) comprises a multi-layer dynamic light source module (22); The sorting mechanism (3) is located below the optical detection system (2) and is used to re-sort the tea leaves; The feeding system (1) further comprises a vibration unit (12) and a driving member (13), wherein the vibration unit (12) is installed at the bottom of the centrifugal dispersion disk (11) and is connected to the optical detection system (2), and the driving member (13) is used to drive the centrifugal dispersion disk (11) to vibrate; The vibration unit (12) comprises 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 (123) and a vibration element (124), and multiple groups of inner vibration layers (122) are separated by the partition (123). The vibration element (124) is used to achieve the reset of the outer shell (121) after compression and extension; Damping balls (125) are connected between the vibration elements (124) between adjacent inner vibration layers (122).

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

3. A color sorter for refined tea production according to claim 2, characterized in that: The LED light source and the near-infrared light source are installed through an annular guide rail, and the irradiation direction of the light source forms an angle of 45° with the camera.

4. A color sorter for refined tea production according to claim 3, characterized in that: A high-pressure airflow nozzle (23) is also provided in the optical detection system (2), and a conical flow guide cavity is provided inside the nozzle of the high-pressure airflow nozzle (23).

5. A color sorter for refined tea production according to any one of claims 1 to 4, characterized in that: The sorting mechanism (3) comprises a sorting unit (31), and the sorting unit (31) comprises a mechanical screen (311), a vibration motor (312), and a guide pipe (313). The mechanical screen (311) is used to sort tea leaves again. The output end of the vibration motor (312) is connected to the mechanical screen (311) to drive the mechanical screen (311) to vibrate. The guide pipe (313) is located below the mechanical screen (311).

6. The color sorter for refined tea production according to claim 5, characterized in that: The sorting units (31) can be arranged into multiple groups.

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