FIELD OF INVENTION

The invention generally relates to the field of extraction of stalks from the tea leaves. More specifically, this invention relates to a method and an apparatus for sequential extraction of tea stalks from the mixture containing withered tea leaves and stalks using optical techniques.

BACKGROUND

Tea is a global beverage. It is consumed in most parts of the world. The majority of tea production occurs in the subtropical areas of Asia, including China, India, Sri Lanka, Japan, and Indonesia. The various types of tea produced differ according to the cultivation practices and the processing methods. Green tea leaves are picked and immediately sent to be dried or steamed to prevent fermentation. The process of green tea production includes but is not limited to cultivation and harvesting, drying and/or withering, steaming, conditioning and shaping.

The method for tea processing includes but is not limited to CTC crush, tear, curl and Orthodox. The process of green tea production includes but is not limited to cultivation and harvesting, drying and/or withering, steaming, conditioning and shaping. One of the major steps in green tea processing includes rolling of the leaves. During the processing of green tea through crush, tear and curl method, hereinafter referred to as CTC, the leaves are passed through three to four sets of rollers or CTC machines. During this process the stalks and stems, tears and opens the rolled leaves. The removal of the stalks and stems prior to rolling improves the quality of the tea and also increases the product value in the market due to the absence of stalk fiber in the CTC tea as well as improved colour and enhanced flavor.

In Orthodox method of processing, after the first rolling process the tea leaves are passed through a roll breaker and the fines are removed using a sifter. The tea leaves are then passed through the second roll where most of the stalks and stems are separated from the leaves. The leaves are again passed through a roll breaker and the fines are removed once again using a sifter.

During the processing of CTC or Orthodox tea, the leaves are rolled or crushed multiple times in the rolling machines or CTC machines. Subsequent to rolling, the stalks and stems are separated from the green withered leaves. The presence of stalks and stems during the rolling process, damages the green withered leaves by tearing and opening the rolled leaves. Quality of the leaves improves immensely, if the stalks and stems are removed prior to the rolling processes. Stalk and stem separation if done before rolling will be a manual process, which is extremely exhaustive and time consuming in large factories. Therefore, there is a need for an extraction machine that significantly reduces the time and process of stalk extraction. BRIEF DESCRIPTION OF DRAWINGS

So that the manner in which the recited features of the invention can be understood in detail, some of the embodiments are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

FIG. 1 shows a batch mode tea stalk extractor, according to an embodiment of the invention.

Fig. 2 shows the initial feeding section of the batch mode tea stalk extractor, according to an embodiment of the invention.

Fig. 3 shows the optical sorting section of the batch mode tea stalk extractor, according to an embodiment of the invention.

Fig. 4 shows a sequential tea stalk extractor, according to an alternate embodiment of the invention.

SUMMARY OF THE INVENTION

One aspect of the invention provides a method for batch mode extraction of tea stalks. The method includes feeding a mixture containing tea leaves and stalks, optically scanning the mixture to detect the stalks from the mixture, performing an initial separation of the tea stalks and the tea leaves.

Another aspect of the invention provides a batch mode tea stalk extractor. The extractor includes a feeding means and an optical chamber coupled to the feeding means. A sorting mechanism is positioned proximal to the optical chamber having a collection unit and an ejection unit.

Another aspect of the invention provides a method for sequential extraction of tea stalks. The method comprises a primary extraction step and a secondary extraction step. The primary extraction step includes feeding a mixture containing withered tea leaves and stalks. The mixture is optically scanned to detect the stalks from the mixture. An initial separation of the tea stalks and the tea leaves is then performed. After the initial separation, the separated stalks are then subjected to a secondary extraction step, for enhanced removal of residual stalk from the initially separated tea stalks.

Another aspect of the invention provides a sequential tea stalk extractor for sequential extraction of tea stalks. The extractor includes a primary extraction arrangement and a secondary extraction arrangement. The primary extraction arrangement includes a primary feeding means. A primary optical chamber is coupled to the primary feeding means. A primary sorting mechanism is positioned proximal to the primary optical chamber having a first collection unit and a first ejection unit. The secondary extraction arrangement includes a secondary feeding means operatively connected downstream to the first ejection unit. A secondary optical chamber is operatively coupled to the secondary feeding means. A secondary sorting mechanism is positioned proximal to the secondary optical chamber having a second collection unit and a second ejection unit. DETAILED DESCRIPTION OF THE INVENTION

Various embodiments of the invention provide a method and a sequential tea stalk extractor for sequential extraction of tea stalks from a mixture containing tea leaves and stalks. Further, a method for batch mode extraction of tea stalks and a batch mode tea stalk extractor are also provided.

The method for batch mode extraction of tea stalks includes feeding a mixture containing tea leaves and stalks, optically scanning the mixture to detect the stalks from the mixture, performing an initial separation of the tea stalks and the tea leaves. The method for sequential tea stalk extraction includes a primary extraction step and a secondary extraction step. The primary extraction includes feeding a mixture containing tea leaves and stalks, optically scanning the mixture to detect the stalks from the mixture, performing an initial separation of the tea stalks and the tea leaves. Further, in the secondary extraction step, the initially separated stalk mixture is subjected to a secondary optical scanning for enhanced removal of residual stalk from the initially separated tea stalks. The methods described hereinabove shall be explained in detail through FIG.1 - FIG.4.

FIG.1 shows a batch mode tea stalk extractor, according to an embodiment of the invention. The extractor includes a feeding means 1 for feeding of a mixture 2 containing tea leaves and stalks. The tea leaves described herein can be green tea leaves or withered tea leaves. The feeding means 1 includes an in-feed hopper 4, an inclined conveyor 6, an outlet hopper 8, a vibratory feeder 10 and a horizontal belt conveyor 12. In one example of the invention, the mixture 2 is fed into the in-feed hopper 4 and the mixture 2 is then passed through the inclined conveyor 6. The inclined conveyor 6 is supported by a supporter 14. The inclined conveyor 6 includes a first end 6a and a second end 6b. Each of the first end 6a and second end 6b are provided with a first motor 16a and a second motor 16b, respectively. Subsequent to passing through the inclined conveyor 6, the mixture 2 is allowed to be fed into the vibratory feeder 10. The feeding of the mixture 2 into the vibratory feeder 10 is achieved through the outlet hopper 8. In another example of the invention, the mixture 2 is directly fed into the vibratory feeder 10.

The mixture 2 in the vibratory feeder 10 is then passed through the horizontal belt conveyor 12. The horizontal belt conveyor 12 is provided with a third motor 18a and a fourth motor 18b respectively. The mixture 2 from the horizontal belt conveyor 12 is then allowed to enter into an optical chamber 3.

The optical chamber 3 is coupled to the feeding means 1 for optical scanning of the mixture 2 to detect the stalks from the mixture 2. The optical chamber 3 is provided with an optical sorting arrangement to identify tea stalks and tea leaves in the mixture 2. A sorting mechanism 5 is positioned proximal to the optical chamber 3 for performing an initial separation of the tea stalks and the tea leaves. The sorting mechanism has a collection unit 20a and an ejection unit 20b. The tea leaves, subsequent to sorting, are allowed to pass through the collection unit 20a and the tea stalks are allowed to pass through the ejection unit 20b, with the help of an ejector chamber 22.

The percentage removal of the tea stalks in a batch mode extraction is 80% to 90%.

Fig. 2 shows the initial feeding section of the batch mode tea stalk extractor, according to an embodiment of the invention. Initially, a mixture 2 containing tea leaves 2a and stalks 2b, is fed into the in-feed hopper 4. The mixture 2, subsequent to being fed through the in-feed hopper 4, is passed through the inclined conveyor 6. The inclined conveyor 6 is supported by a supporter 14. The supporter contains wheel 14a and 14b. The inclined conveyor 6 comprises of a first end 6a and a second end 6b. Each of the first end 6a and second end 6b are provided with a first motor 16a and a second motor 16b, respectively. Subsequent to passing through the inclined conveyor 6, the mixture 2 is allowed to be fed into the vibratory feeder 10. The feeding of the mixture 2 into the vibratory feeder 10 is achieved through the outlet hopper 8.

Fig. 3 shows the optical sorting section of the batch mode tea stalk extractor, according to an embodiment of the invention. In one embodiment of the invention, a mixture containing withered tea leaves and stalks are fed into an optical chamber 3 using a suitable feeding means 1. In another embodiment of the invention, the mixture containing withered tea leaves and stalks fed into the optical extractor directly from the sieving machine after the roll breaker. The optical chamber 3 is configured to identify the tea stalks from the mixture, which is fed into the optical sorting section. The optical chamber 3 is provided with at least a pair of cameras 24a and 24b. These Cameras 24a and 24b are configured to capture a high resolution image of the tea leaves and tea stalks. In one embodiment of the invention, the mixture is illuminated with visible light. In another embodiment of the invention, the mixture is illuminated with infra-red light. In yet another embodiment of the invention, the tea leaves are scanned using the suitable camera from the top and/ or the bottom.

In one example of the invention, the camera can be a single and/or multiple cameras. Further, the camera includes but is not limited a cod camera, a monochromatic camera, a trichromatic camera, an infra-red camera. The illumination of the mixture is achieved by means of suitable foreground lighting and background lighting. The intensity of foreground lighting is adjustable and can be adjusted from batch to batch in order to optimize the separation of tea stalks. Similarly, the intensity of background lighting is adjustable and can be adjusted from batch to batch in order to optimize the separation of tea stalks. Further, the collected data from the camera is processed using various algorithms, subsequent to which the tea stalks and tea leaves are identified on the basis of color and/or shape and/or size and separated from the tea leaves as they pass through the sorting mechanism 5.

The captured images are then fed into an image processing engine for analyzing the captured images and to identify the tea stalks and tea leaves. The identified tea stalks and the tea leaves are then separated with the help of ejector chamber 22 and an air jet 26. The sorting mechanism 5 has a collection unit 20a and an ejection unit 20b. The tea leaves, subsequent to sorting, are allowed to pass through the collection unit 20a and the tea stalks are allowed to pass through the ejection unit 20b, with the help of an ejector chamber 22. Each unit 20a and 20b possesses a nozzle 28a and a nozzle 28b respectively. The separated tea leaves 2a are passed through the nozzle 28a to the collection unit 20a and the tea stalks 2b are passed through the nozzle 28b to the ejection unit 20b.

In order to improve the efficiency of separation, the accepted tea leaves or the rejected stalk are repassed on another belt or on a portion of the same belt and re-inspected and re-separated. In one embodiment of the invention, separation is carried out using timed air jets from pneumatic or air operated valves. In another embodiment of the invention, separation is carried out by means of paddles or any other device.

Fig.4. shows the sequential tea stalk extractor, according to an alternate embodiment of the invention. The extractor includes a primary extraction arrangement 7 and a secondary extraction arrangement 9. The primary extraction arrangement 7 includes a primary feeding means 1 for feeding of the mixture containing tea leaves and stalks. The tea leaves described herein can be green tea leaves or withered tea leaves. The primary feeding means 1 includes atleast one of an in-feed hopper, an inclined conveyor, an outlet hopper, a vibratory feeder or a horizontal belt conveyor. In one embodiment of the invention, the mixture is fed to the vibratory feeder 10. A horizontal belt conveyor 12 is coupled to the vibratory feeder 10 for transferring of the mixture into a primary optical chamber 3. The primary optical chamber 3 is coupled to the primary feeding means 1 for optical scanning of the mixture to detect the stalks from the mixture. The primary optical chamber 3 is configured to identify the tea stalks from the mixture, which is fed into the optical sorting section. The primary optical chamber 3 provides at least a pair of cameras to capture a high resolution image of the tea leaves and tea stalks. A primary sorting mechanism 5 is positioned proximal to the primary optical chamber 3 for performing an initial separation of the tea stalks and the tea leaves. The primary sorting mechanism 5 has a first collection unit 20a and a first ejection unit 20b. The first collection unit 20a contains tea leaves 2a and the first ejection unit 20b contains initially separated stalk mixture 2b.

The secondary extraction arrangement includes a secondary feeding means 1 1 operatively connected downstream to the first ejection unit for feeding the initially separated stalk mixture. In one embodiment of the invention, the mixture transfers into a secondary optical chamber 13 through a horizontal belt conveyor 30. The secondary optical chamber 13 is operatively coupled to the secondary feeding means 1 1 for secondary optical scanning to achieve enhanced removal of residual stalk from the initially separated tea stalks. The primary optical scanning and the secondary optical scanning are achieved in a visible region or infrared region. A secondary sorting mechanism 15 is positioned proximal to the secondary optical chamber 13. The secondary optical chamber 13 has a second collection unit 32a and a second ejection unit 36b. The second ejection unit 32b contains residual tea stalks and the second collection unit 32a contains tea leaves.

The percentage removal of the tea stalks in sequential tea stalk extractor is in the range of 90% to 95%.

The machine as described herein above can be adopted for removing stalks from the mixture containing withered tea leaves, green tea leaves and tea stalks.

Advantages:

· Quality of tea leaves is enhanced.

• Damage to the tea leaves during processing is reduced.

• Time efficient removal of stalks and stems from the tea leaves is done.

• Extraction of stems and stalks is easily done, without any manual efforts.

The foregoing description of the invention has been set for merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.