CONTINUOUS PHYSICAL WITHERING MACHINE

FIELD OF INVENTION
[001] The embodiments herein generally relate to a withering machine  specifically a continuous physical withering machine for efficiently withering tea leaves without much manual interference. More specifically  embodiments described herein relate to a continuous withering machine that helps in the physical wither of tea leaves and which facilitates even distribution of air flow/pressure across the withering machine.

BACKGROUND OF THE INVENTION
[002] One of the most important procedures for producing good quality tea is withering the tea leaves in a proper fashion. It will not be wrong to deem it the most important step in producing quality teas as a slight change in the withering of the leaves result in changes in the tea quality. Withering involves changing the physical and chemical properties of the leaves and the process of natural withering starts immediately after the leaves are plucked. Therefore  leaves are transported in an efficient  quick way so as to reach factory without being damaged.
[003] Withering can be divided into two kinds depending on the type of change that the leaves undergo  namely  physical and chemical. In physical withering  the moisture content is reduced whereas in chemical withering various bio-chemical changes take place in the leaf. Whereas physical withering is important for fermentation  chemical withering is important for flavor. Usually  physical withering takes two to four hours to complete. During physical withering  hot air is blown through the bed of leaves to reduce the moisture content and wither it faster. Chemical withering takes longer time to complete and the process cannot be hastened without compromising on the quality of tea. It takes around eight to sixteen hrs for a chemical wither  depending on the weather conditions  wherein leaves are evenly spread and placed in troughs and fans are used to control the temperature of the air blown.
[004] For both types of withering  machines have been developed for a uniform wither. In physical withering  since it consists mostly of blowing hot air on the tea leaves  a lot of machines have been invented for the same. In these physical withering machines  large amounts of tea leaves are loaded unto the machine and hot air is blown to remove the moisture. Earlier  the leaves were loaded and unloaded manually. Other mechanisms like the one described in GB 872495 (A) were also used wherein an arrangement of trays were devised to continuously load and unload the tea leaves. However  this arrangement consisted of a variety of sprockets  pulleys  trays and chain  making the entire mechanism very complicated and also lead to excessive use of petroleum lubricants.
[005] Since huge quantities of tea are withered in batches  different mechanisms that help in better air-flow through the tea leaves were also devised. For example  in JP 62087047 (A) infra-red radiation was used to heat the tea leaves and in the 1964 patent GB 971377 (A) draught fan was induced in the passage of tea-leaves. Both these patents had there own set of complications. The Japanese Patent had infra-red heater because of which the quality of the tea leaves withered were different from those heated through regular hot air. In the 1964 British Patent  pre-heated air was pumped from a separate unit connected to the trough through passages which entered the tower at the top  passed downwardly there-through and passed out from the bottom of the tower; the hot air circulation thus provided could not blow air through all the trough levels with equal intensity and uniformity.
[006] Moreover  fans constitute an important part of such withering machines. However  most of these fans have to be manually operated. Since different types of tea leaves  depending on the weather conditions  require different time for withering  the circulating air must also be controlled accordingly. Mechanical fans require supervision to turn it on and off or control the temperature of the air to be blown. Moreover  in the conventional open trough  fans are fitted at the inlet or below the trough bed. Their positioning is such that they do not provide efficient blowing of air.
[007] Different methods of blowing air had thus been devised; however  since the trough is usually a very large chamber  the air does not circulate with even intensity through all parts of the chamber and thus the spread tea leaves do not get hot air evenly blown through them  leading to uneven wither and compromise on the quality of tea leaves.
[008] Therefore  there is a need in the prior art to devise a withering chamber which has an air chamber designed to evenly circulate the air through all parts of the chamber thus blowing air evenly on the tea leaves and facilitating a good wither.

OBJECTS OF THE INVENTION
[009] A main object of the invention is to provide a physical withering machine for withering tea leaves.
[0010] Another object of the invention is to provide a continuous physical withering machine that would continuously wither tea leaves.
[0011] Still another object of the invention is to provide tapered air chamber to facilitate even circulation of hot air inside the withering machine.
[0012] Yet another object of the invention is to provide fans with radiators in a manner that would facilitate even circulation of air in the closed trough at a constant set temperature.
[0013] Another object of the invention is to provide fans and radiators that can be automatically operated such that no supervision is required.
[0014] Another object of the invention is to provide a feeding system which spreads the tea leaves efficiently and evenly without any human intervention and in a manner that would prevent damage of the leaves and wastage.
[0015] Another object of the invention is to provide a discharge system that would facilitate even discharge of the tea leaves.
[0016] Another object of this invention is to reduce the area needed for withering.
[0017] The other objects and advantages of the present invention will be apparent from the following description when read in conjunction with the accompanying drawings which are incorporated for illustration of preferred embodiments of the present invention and are not intended to limit the scope thereof.

SUMMARY OF THE INVENTION
[0018] In view of the foregoing  an embodiment herein provides a continuous physical withering machine  wherein the continuous physical withering machine includes a tapered air chamber for even circulation of hot air  a trough having long narrow closed container for withering of tea leaves  atleast a belt conveyor placed in the trough  atleast a fan  a radiator and a conducting duct for producing hot air  atleast a motor to drive the belt conveyor  plurality of sloped passages  plurality of perforated sheets  atleast a feeding system at one end of the trough and atleast a discharge system placed at one end of the trough. The feeding conveyor facilitates even spreading of tea leaves over the belt conveyor and continuous removal of dried leaves without causing any obstruction in the pathway. The tapered air chamber is provided with a taper ratio of 1:100 to 3:100 (ie. 1 to 3 mm taper for100 mm long). Further  the rollers provided at the both ends enable the movement of said belt conveyor at a predetermined speed.
[0019] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood  however  that the following descriptions  while indicating preferred embodiments and numerous specific details thereof  are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof  and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The detailed description is set forth with reference to the accompanying figures. In the figures  the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different figures indicates similar or identical items.
[0021] Fig 1 illustrates the isometric view of the continuous physical withering machine  according to an embodiment herein;
[0022] Fig 2 illustrates the cross sectional view of the continuous physical withering machine  according to an embodiment herein;
[0023] Fig 3 illustrates the side view of the continuous physical withering machine  according to an embodiment herein;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly  the examples should not be construed as limiting the scope of the embodiments herein
[0025] As mentioned  there is a need in the art to provide a continuous physical withering machine that would facilitate even circulation of hot air across the length of the withering machine and ensure proper withering of tea leaves. Referring now to the drawings  and more particularly to FIGS. 1 through 3  where similar reference characters denote corresponding features consistently throughout the figures  preferred embodiments are shown herein.
[0026] Fig. 1 illustrates a general isometric view of the continuous physical withering machine 100 [herein after also referred as [CPW] along with its various parts  according to an embodiment. Accordingly  the CPW machine 100 comprises of a closed withering trough 101  which is a long  rectangular  narrow box with a closed top surface. The dimensions of the trough 101 in most of the factories vary considerably. The width of the trough varies between 2m to 5m and its length varies between 16m to 40m.
[0027] According to an embodiment  CPW machine 100 has one opening at one sides of the machine to facilitate feeding of tea leaves  and another opening at another side of the machine to facilitate discharge of tea leaves. Accordingly  a feeding system 102 is provided to feed tea leaves into the withering trough. The feeding system 102 may comprise a receiving tray  a vibratory system for spreading the leaves evenly over the receiving tray thus avoiding accretion and unexpected breakdowns. The opening on the other end of the CPW machine 100 is provided for the discharge of withered leaves and the air outside the system and hereinafter it is referred to as discharge system 103.
[0028] Additionally  the CPW machine 100 comprises an axial fan 104  a conducting duct 105  a radiator 106 and an air chamber 109 provided on the top of the machine 100. The axial fan 104 blows the air in the forward direction and the conducting duct 105 conducts the air from the fan 104 and pushes into the radiator 106 which converts the ambient air into hot air. The air chamber 109 placed in conjunction with the conducting duct 105 and radiator 106 facilitates even circulation of hot air inside the CPW machine 100. The radiator 106 is configured to control the temperature at a required level for desired duration; therefore the temperature can be kept constant or varied based on the withering processing requirement.
[0029] In an embodiment  the position of the fan 104  connecting duct 105 and the radiator 106 are fixed such that they would facilitate even circulation of air in the air chamber 109 and inside the closed trough 101. The air-flow rate of the fan inside the CPW machine 100 can be maintained in the range of 9 to 20 m3/sec  so as to avoid unnecessary turbulence. The provided fan 104 and radiator 106 can be operated manually or they can be automatically operated such that no supervision is required. Further  one motor drive 107 is provided near the discharge side of the machine  and another motor drive 108 is provided below the feeding side of the machine.
[0030] According to an embodiment of present invention  the cross sectional view of the continuous physical withering machine (CPW) 100 is illustrated in Fig. 2. Accordingly  the CPW machine 100 comprises a platform 201  plurality of belt conveyors 203 A  203 B  203 C hereinafter collectively referred to as 203 operating at various stages of the withering process. The belt conveyor 203 carries the tea leaves from one end to the other end of the trough with the help of plurality of rollers 205  206  207 and 208 placed on the plurality of guiding rails 204 A  204 B  204 C hereinafter collectively referred to as 204  wherein the rollers enables the movement of the belt conveyors at predetermined speed. Further  plurality of perforated sheets 202 A  202 B  202 C  202 D hereinafter collectively referred to as 202 are placed at the different stages of the withering machine. One such perforated sheet 202 is placed near the base of the air chamber 109 and the other sheets are placed above each belt conveyor 203.
[0031] In an embodiment  the platform 201 placed over the air chamber 109 for clearing and maintenance of perforated plate for uniform distribution of air.
[0032] In an embodiment  the belt conveyor 203 is powered by the motor drive 107  108 comprises an AC variator. With the help of the AC variator  the speed of the belt conveyor 203 can be controlled in the range of 0.4 to 1 m/min which is ideal for the smooth movement of tea leaves without causing any accretion. The motor drive107 with an A.C variator provided at the radiator 106 end is responsible for driving the roller 205  in clockwise direction thus making the belt conveyors 203 A and 203 C to move linearly in forward direction with respect to the feed. The other motor drive 108 provided at the discharge 103 end is responsible for driving the roller 207 in anticlockwise direction thus making the belt conveyor 203 B to move linearly in backward direction with respect to the feed.
[0033] Further  when the motor drive 108 starts operating  the belt conveyor 203 starts moving on the drive rollers 205 and 206 immediately after receiving the tea leaves from the feeding system 102 and carries the same to the radiator 106 end. As the tea leaves move inside the air chamber 109  the hot air takes away the moisture content in them and this process continues as the tea leaves pass through consequent belt conveyors 203 B and 203 C for further withering process.
[0034] In an embodiment  smooth sloped passages 209 A  209 B and 209 C are provided in the pathway of moving tea leaves where they get transferred from one conveyor to the subsequent conveyor without any accidental damage to the tea leaves. Furthermore  receiving trays 210A and 210B are provided in proximity to the sloped passage 209 B and 209 C to guide the leaf properly on to the subsequent conveyor without spillage.
[0035] In conventional withering troughs  the upward passage of air through the bed of leaves usually results in the bottom of the bed being withered first and the upper leaves last. To achieve a more even and efficient withering  air is made to pass either from top to the bottom or from bottom to the top through plurality of perforated sheets or trays 202 which are placed over the belt conveyor 203 at every level of conveying thus ensuring optimal flow of hot air inside the closed trough 101. The size of the perforations in the perforated sheets 202 may range from 8% to 12% open area for ensuring optimal flow of hot air through various levels of conveying.
[0036] Fig 3 illustrates the side view of the continuous physical withering machine CPW machine100 according to an embodiment of present invention. It is important that pressure inside the air chamber 109 should be constant throughout the length to have an uniform air flow rate. Accordingly  the air chamber 109 is designed to have a tapered section which extends from the radiator 106 and ends near the feeding system 102. The height of the air chamber 109 at the radiator 106 end (say h1) is kept greater than the height at the other feeding system 102 end (say h2). A tapering section decreases the area towards the end and equalizes the pressure inside the air chamber. Consequently  the hot air enters into the tapered air chamber 109 and descends into the subsequent stages of conveying through the perforated sheets 202 placed inside the closed trough 101. The taper in the air chamber 109 mainly depend on the height of the chamber at both the ends. The height of the air chamber 109 at the radiator 106 end (i.e. h1) and the height of the other end at the feeding system 102 end (i.e. h2) can be in the range of 500 to 1500 mm.
[0037] In an embodiment  the withering trough 101 is provided with plurality of windows or openings 301 with shutters at various places so as to facilitate easy maintenance and supervision of withering process.
[0038] Operation of the Machine: For the withering of tea leaves  the leaves are loaded onto the feeding system 102 which has a provision to spreading the tea leaves uniformly on to the belt conveyor 203 A . After the leaves are loaded  the belt conveyor 203 A with the help of a motor 108 starts moving from one end of the trough 101 to the other with the help of the rollers 205 and 206 placed on the guiding rails 204. Simultaneously  the fan 104 is operated and the air passes through the conducting duct 105 and gets heated in the radiator 106. The hot air then passes into the tapered air chamber 109 and descends into the closed trough 101 through the plurality of perforated sheets 202 placed above the belt conveyor 203.
[0039] As the leaves pass from one conveyor to another conveyor the moisture present in them is taken away by the hot air present in the trough thus facilitating the withering process. Plurality of windows 301 with shutters are provided on the trough 101 for visual inspection and periodic maintenance. Finally  the dried leaves are taken out from the CPW machine 100 by operating the discharge system 103 provided with a shutter. According to an embodiment  the entire withering process takes place inside the CPW machine 100 within the time range of 2 to 4 hours.
[0040] The main advantage of the present invention is that it provides closed trough and a tapered air chamber which facilitates even circulation of hot air across the length of the withering machine  therefore it can provide even and uniform withering irrespective of the weather condition and leaf quality.
[0041] Another advantage of the present invention is that the tapered air chamber provides a smooth circulation of hot air through the perforated sheets placed at different levels of conveying; therefore the quality of tea produced from the CPW enables the manufacturing of tea with uniform and consistent.
[0042] Another advantage of the present invention is that to provide an improved continuous physical withering process without any manual intervention.
[0043] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can  by applying current knowledge  readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept  and  therefore  such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore  while the embodiments herein have been described in terms of preferred embodiments  those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

I Claim:
1. A continuous physical withering machine comprises of:
a tapered air chamber for even circulation of hot air;
a trough having long narrow closed container for withering of tea leaves;
atleast a belt conveyor placed in the trough;
atleast a fan  a radiator and a conducting duct for producing hot air;
atleast a motor to drive the belt conveyor;
atleast a feeding system at one end of the trough; and
atleast a discharge system placed at one end of the trough.
2. The continuous physical withering machine of claim 1  wherein said tapered air chamber in the taper ratio of 1:100 to 3:100
3. The continuous physical withering machine of claim 2 further comprises of plurality of sloped passages for facilitating smooth movement of tea leaves thus avoiding any damage.
4. The continuous physical withering machine of claim 3 further comprises of plurality of perforated sheets placed inside the said trough.
5. The continuous physical withering machine of claim 4 further comprises of plurality of rollers placed over guiding rails.
6. The continuous physical withering machine of claim 5  wherein said rollers enables the movement of said belt conveyor at a predetermined speed.
7. The continuous physical withering machine of claim 1  wherein said fan and radiator is automatically operated.
8. The continuous physical withering machine of claim 1  wherein said feeding system facilitates even spreading of tea leaves over the belt conveyor.
9. The continuous physical withering machine of claim 1  wherein said discharge system facilitates continuous removal of dried leaves without causing any obstruction in the pathway.
10. The continuous physical withering machine of claim1  wherein said machine can be operated continuously without any manual intervention.

Abstract
In view of the foregoing  an embodiment herein provides a continuous physical withering machine for tea withering  wherein said machine includes a tapered air chamber for even circulation of hot air  a trough having long narrow closed container for withering of tea leaves  atleast a belt conveyor placed in the trough  atleast a fan  a radiator and a conducting duct for producing hot air  atleast a motor to drive the belt conveyor  plurality of sloped passages  plurality of perforated sheets  atleast a feeding system at one end of the trough and atleast a discharge system placed at one end of the trough. The feeding system facilitates even spreading of tea leaves over the belt conveyor and discharge system facilitates continuous removal of dried leaves without causing any obstruction in the pathway.
FIG. 2