FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
Drier and method for drying par boiled paddy uniformly continuously
APPLICANTS
Kilburn Engineering Limited, Bhandup West, Mumbai 400 078, Maharashtra, India, an Indian Company
INVENTOR
Arora Premkumar Kartarsingh, Kilburn Engineering Limited, Bhandup West, Mumbai 400 078, Maharashtra, India, an Indian national
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:
FIELD OF THE INVENTION
This invention relates to a drier and method for drying parboiled paddy uniformly continuously.
BACKGROUND OF THE INVENTION
Paddy freshly harvested from the field generally has a moisture content of 20 to 25% Wet Basis (WB) besides having undesirable foreign particles like chaff, pieces of stalk, stones, soil or dust. Freshly harvested paddy is first cleaned by extracting the foreign particles from the paddy by screening and aspiration. In order to reduce breakage and losses and retain the nutritious value and to increase the storage life, cleaned paddy is parboiled by presteaming the paddy, hot water soaking the paddy, draining out water from the paddy and steam cooking the paddy. Parboiled paddy is dried prior to milling and polishing. During steam cooking, getlatinisation of starch in the paddy grains takes place. This helps to harden the grains during drying and reduce breakage of the grains and losses during milling and polishing. If the paddy is not uniformly cooked and dried, it becomes powdery when stored for a long period of time. Hot water soaking is carried out generally at 55 to 60 °C during which the moisture content of the paddy increases to 30 to 34% WB. Cooking with steam is carried out generally at 85 to 100 °C in a batchwise manner in a cooking vessel fitted with manually operated paddy inlet valve, paddy outlet valve and steam inlet valve. Steam cooking is carried out by injecting steam into a mass of paddy from the top and through the center thereof.
Parboiled paddy has a moisture content of 36-37% WB and is usually dried in a LSU (Louisiana State University) drier which basically comprises a rectangular vessel. Feed rate of paddy into the drier is controlled through a rotary feeder provided at the bottom thereof. Paddy is dried by circulating the paddy in the drier from the bottom to the top of the drier with the help of a mechanical elevator. Baffles are provided in the drier to allow hot air being blown into the drier to contact the paddy during circulation. Usually the paddy is dried to a moisture content of 12 to 14 % WB, which is known as the equilibrium level of drying. The extent of drying in a LSU drier will depend upon the number of passes of the paddy in the drier from the bottom to the top of the drier. Usually 6 to 8 numbers of passes are required to dry the paddy to a moisture content of 12 to 14% WB in a typical LSU drier. Since the paddy is parboiled batchwise, drying of the parboiled paddy is also carried out in the LSU drier in a batchwise manner. As a result of the batchwise operation, a long time is required for parboiling and drying the paddy and productivity is reduced and the drier capacity is not fully utilized. During cooking, since steam is injected only from the top of the mass of paddy through the center thereof, the mass of paddy is not uniformly cooked at the outer layers thereof as steam does not penetrate into the outer layers at the periphery of the mass of paddy uniformly. Due to non-uniform cooking, non-uniform drying of the paddy also takes place. Non-uniform cooking and drying will increase the breakage and losses and reduce the output and also the nutritious value of the milled and polished paddy. Removal of husk during milling also becomes difficult. Manual operation of the cooking vessel is also inconvenient and cumbersome to carry out. Further thermal energy requirement of the drier for drying the paddy mass is high.
In our Indian Patent Application No 1 l/MUM/2009 filed on 2nd January 2009, we have described a continuous method and a system for processing paddy wherein cleaned, presteamed, hot water soaked and water drained paddy mass is continuously and uniformly steam cooked and continuously predried prior to drying. The predrying is generally carried out to a moisture content of 18 to 20% WB. The predried paddy is required to be further dried in a drier like LSU drier.
OBJECTS OF THE INVENTION
An object of the invention is to provide a method for drying parboiled paddy uniformly continuously, which method is simple to carry out and consumes reduced thermal energy and is economical and reduces the drying time of the paddy and breakage and losses of paddy and increases the productivity and efficiency of production and retains the nutritious value of the paddy and increases the storage life of the paddy.
Another object of the invention is to provide a drier for drying parboiled paddy uniformly continuously, which drier is simple in construction and consumes reduced thermal energy and is economical and reduces the processing time of paddy and breakage and losses of paddy and increases the productivity and efficiency of production and retains the nutritious value of the paddy and increases the storage life of the paddy.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided a method for drying parboiled paddy uniformly continuously, the method comprising drying a bed of parboiled paddy to a moisture content of 33 to 34% WB (Wet Basis) with atmospheric air in an atmospheric air drying chamber by forcing atmospheric air through the bed of paddy at the bottom of the atmospheric air drying chamber from below the bed of paddy with progressively reducing force from the beginning of the bed of paddy upto the end of the bed of paddy and simultaneously moving the bed of paddy forward under the progressively reducing force of the atmospheric air and further drying the bed of paddy to a moisture content of 12 to 14% WB with hot air in three stages in succession, each of the stages comprising forcing hot air through the bed of paddy at the bottom of a hot air drying chamber from below the bed of paddy and moving the bed of paddy forward under vibration of the bed of paddy and under the force of the hot air and temperature conditioning the paddy to reduce the temperature gradient across the paddy grains, the first stage comprising forcing hot air through the bed of paddy at 110 to 120°C and temperature conditioning the paddy with hot air at 40 to 45°C to bring down the moisture content of the paddy to 20 to 22 % WB, the second stage comprising forcing hot air through the bed of paddy at 70 to 80°C and temperature conditioning the paddy with hot air at 45 to 60°C to bring down the moisture content of the paddy to 16 to 18% WB and the third stage comprising forcing hot air through the bed of paddy at 60 to 70°C and temperature conditioning the paddy with hot air at 40 to 45°C to bring down the moisture content of the paddy to 12 to 14% WB.
According to the invention there is also provided a drier for drying parboiled paddy uniformly continuously, the drier comprising an atmospheric air drying unit having an atmospheric air drying chamber with a perforated bottom and a feed inlet at the inlet end thereof and a discharge outlet at the discharge end thereof, the atmospheric air drying chamber being connected at the top thereof to an air exhaust chimney through atleast one cyclone separator and having at the bottom thereof a plurality of air inlet passages connected to a forced atmospheric air supply and provided with air control valves to allow atmospheric air to flow through the air inlet passages at the bottom of the drying chamber with a progressively reducing force and create progressively reducing air pressure zones from the inlet end to the discharge end of the atmospheric air drying chamber to take away the heat and moisture content of a bed of parboiled paddy on the perforated bottom of the atmospheric air drying chamber and to move the bed of paddy forward and three hot air drying units in a row in succession, each of the hot air drying units comprising a hot air drying chamber having a channel shaped vibratory plenum chamber extending along the length of the hot air drying chamber, the plenum chamber having a feed inlet at the inlet end thereof, a discharge outlet at the discharge end thereof and an exhaust air outlet and being connected to a forced hot air supply at the inlet end thereof, the plenum chamber being supported on a hollow support structure with the help of springs and comprising a plurality of openings along the length of the base thereof and drive means connected to the support structure to impart sinusoidal movement to the plenum chamber and a temperature conditioner vessel comprising an open top and a conical bottom, the conical bottom having a discharge end with a control valve, a hollow central tube located vertically at the centre of the vessel and having a hot air inlet at the top thereof connected to a forced hot air supply and a plurality of hot air distributor arms projecting radially from the lower part of the central tube and connected to the central tube and a bucket elevator located between the hot air drying chamber and the temperature conditioner vessel adapted to receive dried paddy being discharged from the hot air drying chamber and convey the dried paddy to the temperature conditioner vessel at the open top thereof and an endless conveyor horizontally linearly movably disposed below the temperature conditioner of the third hot air drying unit, the endless conveyor having a feed end and a discharge end, the discharge end of the temperature conditioner of the third hot air drying unit being disposed directly above the feed end of the endless conveyor, the hot air drying chamber of the first hot air drying unit being located in the proximity of the discharge end of the atmospheric air drying chamber adapted to receive atmospheric air dried paddy being discharged from the atmospheric air drying chamber, the discharge end of the temperature conditioner vessel of the first hot air drying unit opening into the feed inlet of the plenum chamber of the hot air drying chamber of the second hot air drying unit and the discharge end of the temperature conditioner vessel of the second hot air drying unit opening into the feed inlet of the plenum chamber of the hot air drying chamber of the third hot air drying unit, the hot air forced through the hot air drying chambers of the first, second and third hot air drying units being at 110 - 120°C, 70 - 80°C and 60 - 70°C, respectively and the hot air forced through the respective temperature conditioner vessels being at 40 - 45°C, 45 - 50°C and 40 - 45°C respectively.
The following is a detailed description of the invention with reference to the accompanying drawings, in which:
Fig 1 is a schematic flow diagram of the drier for drying parboiled paddy uniformly continuously according to an embodiment of the invention;
Fig 2 is an elevation of the atmospheric air drying unit of the drier of Fig 1;
Fig 3 is a scrap view of the perforated bottom of the drying chamber of the drying unit of Fig 2;
Fig 4 is an isometric view of the hot air drying chamber of the drier of Fig 1;
Fig 5 is an isometric view of the vibratory plenum chamber of the drying chamber of Fig 4;
Fig 6 is an enlarged view of part of the base of the plenum chamber of Fig 5;
Figs 7, 8 and 9 are elevation, plan view and side view of the drive means of the plenum chamber of Fig 4;
Fig 10 is a crossectional view of the driven shaft of the drive means of Figs 7, 8 and 9;
Fig 11 is an elevation of the temperature conditioner vessel of the drier of Fig 1;
Fig 12 is a plan view of the temperature conditioner vessel of Fig 11;
Fig 13 is an isometric view of an air distributor arm of the temperature conditioner vessel of Fig 11; and
Fig 14 is a crosssectional view of the air distributor arm of Fig 13.
The drier 1 for drying parboiled paddy (not shown) uniformly continuously as illustrated in Figs 1 to 14 of the accompanying drawings comprises an atmospheric air drying unit 2 having an atmospheric air drying chamber 3 with a perforated bottom 4 (perforations marked 5) and a feed inlet 6 at the inlet end thereof 7 and a discharge outlet 8 at the discharge end 9 thereof. The drying chamber 3 is connected at the top thereof to an air exhaust chimney 10 through a cyclone separator 11. The drying chamber 3 has at the bottom thereof a plurality of air inlet passages 14 connected to a forced atmospheric air supply line 15 and provided with air control valves 16 to allow atmospheric air to flow through the air inlet passages at the bottom of the drying chamber 3 with a progressively reducing force and create progressively reducing air pressure zones from the inlet end to the discharge end of the drying chamber 3. (Figs 1, 2 and 3). The drier also comprises three hot air drying units 16 in a row in succession. Each of the hot air drying units 17 comprises a hot air drying chamber 18 having a channel shaped vibratory plenum chamber 19 extending along the length of the hot air drying chamber. The plenum chamber has a feed inlet 20 at the inlet end 21 thereof, a discharge outlet 22 at the discharge end 23 thereof and an exhaust air outlet 24. The sidewalls of the plenum chamber are marked 25. The plenum chamber comprises a plurality of openings 26 along the base 27 thereof. The plenum chamber is connected to a forced hot air supply line 28 at the inlet end thereof and is supported on a hollow support structure 29 with the help of springs 30. (Figs 1, 4, 5 and 6). 31 is an electric motor mounted on supports 31a and having a driver pulley 32 mounted on the shaft 33 thereof. 34 is a driven shaft disposed parallel to the motor shaft and rotatably mounted on a pair of spaced apart upright members 35, 35. 36 is a driven pulley mounted on the driven shaft at one end thereof corresponding to the driver pulley on the motor shaft. The driver and driven pulley are interconnected by a belt 37. 38 is a cam integrally formed on the driven shaft 34. A cam follower comprising a first bearing 39 is disposed over the cam. 40 is a crosspin rigidly connected across a bracket 41 which in turn is connected across the support structure. 42 is a second bearing mounted on the crosspin and coupled to the first bearing. The support structure comprises an access window 43 (Figs 5, 7, 8, 9 and 10). The hot air drying unit also comprises a temperature conditioner vessel 44 having an open top 45 and a conical bottom 46. The conical bottom has a discharge end 47 provided with a control valve 48. A hollow central tube 49 is located vertically at the centre of the vessel. The central tube has a hot air inlet 50 at the top thereof connected to a forced hot air supply (not shown) and a plurality of hot air distributor arms 51 projecting radially from the lower end thereof. Each of the distributor arms comprises a pair of angular members 52a, 52b disposed one above the other in spaced apart relationship and fixed together with spaced apart ribs 52c. The space between the angular members is marked 52d and is connected to matching openings (not shown) in the sidewall of the central tube. The openings in the sidewall of the central tube have not been shown as such can be easily visualised and understood. (Figl, 11, 12, 13 and 14). 53 is a bucket elevator located between each of the hot air drying chambers and the respective temperature conditioner vessel adapted to receive dried paddy being discharged from each of the hot air drying chambers and convey the dried paddy to the respective temperature conditioner vessel (Fig 1). 54 is an endless conveyor horizontally linearly movably disposed below the temperature conditioner vessel of the third hot air drying unit. The endless conveyor has a feed end 55 and a discharge end 56. The discharge end of the temperature conditioner of the third hot air drying unit is disposed directly above the feed end of the endless conveyor. The hot air drying chamber of the first hot air drying unit is located in the proximity of the discharge end of the atmospheric air drying chamber adapted to receive atmospheric air dried paddy being discharged from the atmospheric air drying unit (Fig 1). The discharge end of the temperature conditioner vessel of the first hot air drying unit is opening into the feed inlet of the plenum chamber of the hot air drying chamber of the second hot air drying unit and the discharge end of the temperature conditioner vessel of the second hot air drying unit is opening into the feed inlet of the plenum chamber of the hot air drying chamber of the third hot air drying unit (Fig 1).
During working of the drier, cleaned, presteamed, hot water soaked, water drained and steamed cooked paddy, preferably uniformly steam cooked paddy is continuously fed into the drying chamber 3 of the atmospheric air drying unit 2 via the inlet 6 thereof. Uniform cooking of the water drained paddy mass may be carried out as described in our patent application No 1 l/MUM/2009. Steam cooked paddy has generally a moisture content of 36 to 37% WB (Wet Basis). The paddy spreads on the perforated bottom 5 of the drying chamber 3 and forms a bed. The air control valves 16 in the air inlet passages 14 at the bottom of the drying chamber are so set as to regulate the flow of atmospheric air being forced through the air inlet passages in a progressively reducing manner and to create at the bottom of the drying chamber below the perforated bottom thereof air pressure zones with a progressively reducing force from the inlet end to the discharge end of the drying chamber and to take away the heat and the moisture of the bed of paddy and to move the bed of paddy forward. The atmospheric air dried paddy is discharged through the discharge outlet 8 of the atmospheric air drying unit. The air in the atmospheric air drying unit is exhausted to the atmosphere through the chimney 10 via the cyclone separator 11. While passing through the cyclone separator foreign particles like chaff, fibre or dust
from the paddy getting transferred into the air are trapped by the cyclone separator and
*
are collected from the cyclone separator. During atmospheric air drying, the moisture content of the paddy reduces to about 33 to 34% WB. Atmospheric air dried paddy mass being discharged from the atmospheric air drying unit 2 is fed into the vibratory plenum chamber 19 of the hot air drying chamber 18 of the first hot air drying unit 17 in the proximity of the atmospheric air drying unit via the inlet 20 at the inlet end 21 of the first hot air drying unit. During operation of the first hot air drying unit, the motor shaft 33 rotates and transmits the drive to the driven shaft 34 via the driver pulley 32, driven pulley 36 and belt 37 and cause the driven shaft to rotate. Due to rotation of the driven shaft, the first bearing 39 describes a smooth and gentle up and down rotational movement over the cam 38 of the driven shaft resembling motion along a smooth curvature or a sinewave in the forward direction. As a result, the second bearing 42 along with crosspin 40, bracket 41, hollow support structure 29 and plenum chamber 19 describes a sinusoidal movement in the vertical plane in the forward direction. The paddy mass being fed into the plenum chamber spreads on the base 27 of the plenum chamber and forms a bed of paddy. Hot air at 110 to 120°C being forced through the openings 26 at the base of the plenum chamber via the hot air supply line 28 lifts up the grains of paddy slightly and also turn or swing them around. The air blown through the bed of grains comes in contact with all the gains and all around the grains. The hot air flow is controlled so as to give a forward momentum to the grains. As a result of the sinusoidal vibratory movement of the plenum chamber and the force of the incoming hot air, the grain mass moves forward on the plenum chamber like a fluidized bed with practically no friction. There is intense heat and mass transfer and moisture is removed from the grains veiy effectively and the grains are uniformly dried very fast to a moisture content of 20 to 22% WB. The hot air is let out into the atmosphere via the exhaust air outlet 24 of the hot air drying unit. The sidewalls 25 of the plenum chamber prevent the grains from falling down from the sides of the plenum chamber while moving forward on the base of the plenum chamber. The steel springs give flexibility to the plenum chamber to vibrate and describe the sinusoidal motion but at the same time hold the plenum chamber firmly. The hot air dried paddy being discharged from the discharge outlet 22 of the first hot air drying unit is continuously fed into the temperature conditioner vessel 44 of the first hot air drying unit via the rsepective bucket elevator 53 and open top of the vessel. Temperature conditioning of the paddy is carried out by forcing hot air at 40 to 45°C into the vessel 44 via the inlet 50 thereof. The hot air travels down in the central tube 49 and to the air distributor arms 51. The hot air is distributed across the entire paddy mass in the vessel through the space 52d between the angular members 52a, 52b of each of the distributor arms 51. The hot air being distributed through the distributor arms rises up through entire paddy mass from the bottom of the paddy mass and escape into the atmosphere via the open top 45 of the vessel. A residence time for the paddy in the vessel is provided by regulating the discharge rate of the paddy from the vessel with the control valve 48 at the bottom of the vessel. Paddy dried at 110 to 120°C and being fed into the temperature conditioner vessel will have a higher temperature gradient across the grains as the temperature at the outer side of the grains will be much higher than the temperature at the core of the grains and as it takes time for the heat to penetrate to the core of the grains. During temperature conditioning of the grains in the vessel heat at the outer surface of the grains penetrates into the core and helps to equalize the temperature both at the outer surface of the grains and the core of the grains to a great extent. Therefore, the temperature gradient across the grains is substantially reduced. Uniform distribution of the air across the entire crosssection of the paddy in the vessel helps to achieve uniform temperature conditioning of the paddy. A conditioning temperature of 40 to 50°C of the incoming air which is lower than that of the temperature of the grains at the outer side thereof, also helps to equalize the temperature at the outer side of the grains and to reduce the temperature gradient across the grains and equalize the temperature across the grains. The hot air dried paddy from the first hot air drying unit is subsequently discharged into the inlet of the second hot air drying unit and dried and temperature conditioned with hot air therein. The hot air dried paddy from the second hot air drying unit is subsequently discharged into the inlet of the third hot air drying unit and dried and temperature conditioned with hot air. Drying and temperature conditioning of the paddy in the second and third drying units are carried out in the same manner as in the first hot air drying unit. However, the temperature of the hot air in the hot air drying chamber and temperature conditioner vessel of the second hot air drying unit is maintained at 70 to 80°C and 40 to 45°C, respectively so as to reduce the moisture content of the paddy to 16 to 18% WB and the temperature of the hot air in the hot air drying chamber and temperature conditioner vessel of the third hot air drying unit is maintained at 60 to 70°C and 40 to 45°C so as to reduce the moisture content of the paddy mass to 1'2 to 14% WB. The dried paddy being finally discharged from the temperature conditioner vessel of the third hot air drying unit falls on the conveyor 54 and is carried on the conveyor 54 for milling and polishing
According to the invention, steamed cooked paddys preferably continuously and uniformly steam cooked paddy, is continuously dried to the equilibrium level of 12 to 14% WB prior to milling and polishing. The invention eliminates a drier like LSU drier which is very costly and energy consuming. Use of atmospheric air for initial drying of the grains also reduces thermal energy requirement of the drier. Therefore, there is substantial cost benefit in terms of drier cost and saving in thermal energy requirement for drying. Due to the continuous steam cooking and drying, processing time is substantially reduced and productivity and process and drier efficiency are substantially increased. Breakage of grains and losses are reduced, output or yield is improved and nutritious value of the paddy mass is retained. During milling dehusking is also very effectively achieved. The drier of the invention is also simple in construction and easy and convenient to operate as the drying units are simple in construction and easy and convenient to operate.
The above embodiment of the invention is by way of example only and should not be construed and understood to be limiting the scope of the invention. We have found one atmospheric air drying unit and three hot air drying units optimal to achieve the equilibrium level of drying of the paddy. However, there can be more than one atmospheric air drying unit and more than three hot air drying units with appropriate hot air temperature distribution. The construction and configuration of the atmospheric air drying unit and hot air drying units can be different. The construction and configuration of the temperature conditioner vessel can be different. There can be one or more than one cyclone separator. The drive means for the plenum chamber can be of a different configuration and construction. The cam follower comprising the first bearing will ensure smooth and friction free rotation and reduce wear and tear to the cam. The second bearing is optional but because of the second bearing the load on the crosspin is effectively borne by the second bearing and damage to the crosspin is minimized. It also gives certain amount of flexibility to the crosspin. As a result, the life of the cross pin is increased. The construction and configuration of the plenum chamber can vary. The invention is basically in uniformly continuously drying steam cooked paddy in stages with the different temperatures and in the temperature conditioning of the paddy at each stage. Variations in the construction and configuration of the invention which are obvious to those skilled in the art are to be construed and understood to be within the scope of the invention.
We claim
1. A method for drying parboiled paddy uniformly continuously, the method comprising drying a bed of parboiled paddy to a moisture content of 33 to 34% WB (Wet Basis) with atmospheric air in an atmospheric air drying chamber by forcing atmospheric air through the bed of paddy at the bottom of the atmospheric air drying chamber from below the bed of paddy with progressively reducing force from the beginning of the bed of paddy upto the end of the bed of paddy and simultaneously moving the bed of paddy forward under the progressively reducing force of the atmospheric air and further drying the bed of paddy to a moisture content of 12 to 14% WB with hot air in three stages in succession, each of the stages comprising forcing hot air through the bed of paddy at the bottom of a hot air drying chamber from below the bed of paddy and moving the bed of paddy forward under vibration of the bed of paddy and under the force of the hot air and temperature conditioning the paddy to reduce the temperature gradient across the paddy grains, the first stage comprising forcing hot air through the bed of paddy at 110 to 120°C and temperature conditioning the paddy with hot air at 40 to 45°C to bring down the moisture content of the paddy to 20 to 22 % WB, the second stage comprising forcing hot air through the bed of paddy at 70 to 80°C and temperature conditioning the paddy with hot air at 45 to 60°C to bring down the moisture content of the paddy to 16 to 18% WB and the third stage comprising forcing hot air through the bed of paddy at 60 to 70°C and temperature conditioning the paddy with hot air at 40 to 45 °C to bring down the moisture content of the paddy to 12 to 14% WB.
2. The method as claimed in claim 1, wherein the parboiled paddy is uniformly and continuously steam cooked.
3. The method as claimed in claim 1 or 2, wherein the paddy is temperature conditioned in a temperature conditioner vessel by forcing hot air through the paddy and regulating the discharge rate of the paddy from the vessel to provide a residence time for the paddy in the vessel.
4. The method as claimed in claim 3, wherein the paddy is temperature conditioned by forcing hot air through the paddy uniformly.
5. A drier for drying parboiled paddy uniformly continuously, the drier comprising an atmospheric air drying unit having an atmospheric air drying chamber with a perforated bottom and a feed inlet at the inlet end thereof and a discharge outlet at the discharge end thereof, the atmospheric air drying chamber being connected at the top thereof to an air exhaust chimney through atleast one cyclone separator and having at the bottom thereof a plurality of air inlet passages connected to a forced atmospheric air supply and provided with air control valves to allow atmospheric air to flow through the air inlet passages at the bottom of the drying chamber with a progressively reducing force and create progressively reducing air pressure zones from the inlet end to the discharge end of the atmospheric air drying chamber to take away the heat and moisture content of a bed of parboiled paddy on the perforated bottom of the atmospheric air drying chamber and to move the bed of paddy forward and three hot air drying units in a row in succession, each of the hot air drying units comprising a hot air drying chamber having a channel shaped vibratory plenum chamber extending along the length of the hot air drying chamber, the plenum chamber having a feed inlet at the inlet end thereof, a discharge outlet at the discharge end thereof and an exhaust air outlet and being connected to a forced hot air supply at the inlet end thereof, the plenum chamber being supported on a hollow support structure with the help of springs and comprising a plurality of openings along the length of the base thereof and drive means connected to the support structure to impart sinusoidal movement to the plenum chamber and a temperature conditioner vessel comprising an open top and a conical bottom, the conical bottom having a discharge end with a control valve, a hollow central tube located vertically at the centre of the vessel and having a hot air inlet at the top thereof connected to a forced hot air supply and a plurality of hot air distributor arms projecting radially from the lower part of the central tube and connected to the central tube and a bucket elevator located between the hot air drying chamber and the temperature conditioner vessel adapted to receive dried paddy being discharged from the hot air drying chamber and convey the dried paddy to the temperature conditioner vessel at the open top thereof and an endless conveyor horizontally linearly movably disposed below the temperature conditioner of the third hot air drying unit, the endless conveyor having a feed end and a discharge end, the discharge end of the temperature conditioner of the third hot air drying unit being disposed directly above the feed end of the endless conveyor, the hot air drying chamber of the first hot air drying unit being located in the proximity of the discharge end of the atmospheric air drying chamber adapted to receive atmospheric air dried paddy being discharged from the atmospheric air drying chamber, the discharge end of the temperature conditioner vessel of the first hot air drying unit opening into the feed inlet of the plenum chamber of the hot air drying chamber of the second hot air drying unit and the discharge end of the temperature conditioner vessel of the second hot air drying unit opening into the feed inlet of the plenum chamber of the hot air drying chamber of the third hot air drying unit, the hot air forced through the hot air drying chambers of the first, second and third hot air drying units being at 110 - 120°C, 70 - 80°C and 60 - 7()°C, respectively and the hot air forced through the respective temperature conditioner vessels being at 40 - 45°C, 45 - 50°C and 40 - 45°C respectively.
6. The drier as claimed in claim 5, wherein the hot air distributor arms each comprises a pair of angular members disposed one above the other in spaced apart relationship and fixed together with spaced apart ribs.
7. The drier as claimed in claim 5 or 6, wherein the drive means comprises an electric motor having a driver pulley mounted on the shaft thereof, a driven shaft disposed parallel to the motor shaft and rotatably mounted on a pair of spaced apart upright members, a driven pulley mounted on the driven shaft at one end thereof corresponding to the driver pulley on the motor shaft, the driver and driven pulleys being interconnected by a belt, a cam provided on the driven shaft and a cam follower engaged over the cam and connected across the support structure through a cross connector means.
8. The drier as claimed in claim 7, wherein the cam is integrally formed on the driven shaft.
9. The drier as claimed in claim 7 or 8, wherein the cam follower comprises a first bearing and the cross connector means comprises a crosspin rigidly connected across a bracket which in turn is connected across the support structure and a second bearing mounted on the crosspin and coupled to the first bearing.
10. The drier as claimed in any one of claims 5 to 9, wherein the support structure comprises an access window.
11. The drier as claimed in any one of claims 5 to 10, wherein the temperature conditioner vessel is cylindrical shaped.
Dated this 19th day of March 2010