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
Method and drier for drying raw 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 method and drier for drying raw paddy uniformly continuously. BACKGROUND OF THE INVENTION
Paddy freshly harvested from the field generally has a moisture content of 20 to 25% WB (Wet Basis) and contains 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 mass by screening and aspiration. Prior to milling and polishing, cleaned paddy is wetted with steam at about 90 to 100 °C for about 5 minutes and dried in order to increase the storage life thereof. Steaming is optional and is carried out in a batch wise manner in a vessel fitted with manually operated paddy inlet valve, paddy outlet valve and steam inlet valve. During steaming, steam is injected into the paddy mass from the top and through the center of the paddy mass. Steaming is carried out to change the colour of the paddy from white to brown (also known as golden rice) but increases the moisture content of the paddy marginally.
Drying of the paddy is usually carried out 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 mass 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 mass during circulation. Usually the paddy mass is dried to a moisture content of 12 to 14 % WB, which is the equilibrium level of drying. The extent of drying in a LSU drier will depend upon the number of passes of the paddy mass in the drier from the bottom to the top thereof. Usually 5 to 6 numbers of passes are required to dry the paddy mass to a moisture content of 12 to 14% WB in a typical LSU drier. Steam wetting, if any and drying of the paddy mass are carried out in the LSU drier in a batchwise manner. As a result of the batchwise operation, a long time is required for steaming and drying the paddy mass and productivity is reduced and drier capacity is not fully utilized. During steaming, since steam is injected only from the top of the paddy mass through the center of the paddy mass, the paddy mass is not uniformly wetted at the outer layers thereof as steam does not penetrate into the outer layers at the periphery of the paddy mass uniformly. This also leads to non-uniform drying of the paddy mass. Non-uniform steaming 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 steaming vessel is also inconvenient and cumbersome to carry out. Further thermal energy requirement of the LSU 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 raw paddy uniformly continuously, which method reduces the drying time and breakage and losses of paddy and increases the productivity and production efficiency 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 method for drying raw paddy uniformly continuously, which method is energy efficient and economical.
Another object of the invention is to provide a drier for drying raw paddy uniformly continuously, which drier reduces the drying time and breakage and losses of paddy and increases the productivity and production efficiency 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 raw paddy uniformly continuously, which drier is energy efficient and economical.
Another object of the invention is to provide a a drier for drying raw paddy uniformly continuously, which drier is simple in construction and easy and convenient to operate.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided a method for drying raw paddy uniformly continuously, the method comprising drying a bed of cleaned paddy to a moisture content of 12 to 14% WB (Wet Basis) with hot air in two 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 70 to 80°C and temperature conditioning the paddy with hot air at 40 to 45°C to bring down the moisture content of the paddy to 16 to 18 % WB and the second stage comprising forcing hot air through the bed of paddy at 60 to 70°C and temperature conditioning the paddy with hot air at 45 to 50°C to bring down the moisture content of the paddy to 12 to 14% WB.
Preferably the cleaned paddy is uniformly continuously steam wetted prior to drying. Preferably the paddy is uniformly continuously steam wetted in an automated steaming vessel by automatically controlling the feed rate of the paddy into the steaming vessel and the discharge rate of paddy from the steaming vessel and by automatically controlling the steam feed rate into the steaming vessel and by simultaneously injecting steam through the center of the paddy mass radially outwardly and by injecting steam from the periphery of the paddy mass radially inwardly along the entire height of the paddy mass. Preferably 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. Preferably the paddy is temperature conditioned by forcing hot air through the paddy uniformly.
According to the invention there is also provided a drier for drying cleaned paddy uniformly continuously, the drier comprising two 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 line 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 second hot air drying unit, the endless conveyor having a feed end and a discharge end, the discharge line of the temperature conditioner of the second hot air drying unit being disposed directly above the feed end of the endless conveyor, the discharge line 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, the hot air forced through the hot air drying chamber of the first and second hot air drying units being at 70 - 80°C and 60 - 70°C, respectively and the hot air forced through the respective temperature conditioner vessels being at 40 - 45°C and 45 - 50°C, respectively.
According to an embodiment of the invention the drier comprises an automated steaming vessel for uniformly continuously steam wetting the cleaned paddy prior to drying. According to an embodiment of the invention the automated steaming vessel comprises a plurality of spaced apart perforated steaming chambers surrounded by a steam jacket in spaced apart relationship therewith and connected to a paddy inlet passage at the top thereof and to a paddy discharge passage at the bottom thereof, each of the perforated steaming chambers being provided with a centrally located perforated steam injector tube, the paddy inlet passage being provided with a feed rate metering device and the paddy discharge passage being provided with a discharge rate metering device, the steam jacket being provided with a steam inlet passage, the steam inlet passage and the steam injector tubes being connected to a steam source through a steam control valve, the feed rate metering device and the discharge rate metering device and the steam control valve being connected to a logic control automatically to control the paddy feed rate through the paddy inlet passage and paddy discharge rate through the paddy discharge passage and steam flow rate through the steam control valve.
Preferably the logic control is a Programmable Logic Control (PLC). Preferably the steam jacket is provided with an inspection window. Preferably the steaming chambers have diverging openings at the top thereof and the steaming vessel has a converging portion at the bottom thereof. According to an embodiment of the invention 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. Preferably the cam is integrally formed on the driven shaft. Preferably 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. Preferably the support structure comprises an access window.
Preferably the temperature conditioner vessel is cylindrical shaped. Preferably 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.
The following is a detailed description of the invention with reference to the accompanying drawings, in which:
Fig 1A is a flow diagram of the drier for drying raw paddy uniformly continuously according to an embodiment of the invention;
Fig IB is a flow diagram of the drier for drying raw paddy uniformly continuously according to another embodiment of the invention;
Fig 2 is a partly cut isometric view of the automated steaming vessel of the drier of Fig 1A;
Fig 3 is an isometric view of a perforated steam injector tube of the steaming vessel of Fig 2;
Fig 4 is a block diagram of the feed rate metering device, discharge rate metering device and steam control valve and the programmable logic control (PLC) of the automated steaming vessel of Fig 2;
Fig 5 is an isometric view of the first and second hot air drying units of the drier of Fig 1A or Fig IB;
Fig 6 is an isometric view of the vibratory plenum chamber of the drying unit of Fig 5; Fig 7 is a scrap of the base of the plenum chamber of Fig 6;
Figs 8, 9 and 10 are elevation, plan view and side view of the drive means of the drying unit of Fig 5;
Fig 11 is a crosssectional view of the driven shaft of the drive means of Figs 8, 9 and 10;
Figs 12 and 13 are elevation and plan view of the temperature conditioner vessel of the drier of Fig 1A or Fig IB;
Fig 14 is an isometric view of a distributor arm of the temperature conditioner vessel of Figs 12 and 13; and
Fig 15 is a cross sectional view of the distributor arm of Fig 14.
The drier 1A for drying raw paddy uniformly continuously as illustrated in Figs 1A and 2 to 15 of the accompanying drawings comprises an automated steaming vessel 2 for steam wetting cleaned paddy uniformly continuously. The steaming vessel comprises four spaced perforated steaming chambers 3 surrounded by a steam jacket 4 in spaced apart relationship therewith and connected to a feed passages 5 at the top thereof and to a discharge passage 6 at the bottom thereof (Figs 1A and 2). Perforations of the steaming chambers are marked 7. Each of the perforated steaming chambers is provided with a centrally located perforated steam injector tube 8 having perforations 9. (Figs 2 and 3). The feed passage 5 is provided with a feed rate metering device, preferably a rotary valve 10. The discharge passage is provided with a discharge rate metering device, preferably a rotary valve 11. The steam jacket 4 is provided with a steam passage 12. The steam passage and the steam injector tubes are connected to a steam source (not shown) through a steam control valve 13. Ducts connecting the steam control valve to the four steam injector tubes 8 are marked 14a, 14b, 14c and 14d, respectively (Fig 4). The feed rate metering device and the discharge rate metering device and the steam control valve are connected to a logic control circuit, preferably a programmable logic control (PLC) 15. 16 is an inspection window provided in the steam jacket. The steaming vessel is provided with condensate outlet 17 to allow steam condensate in the steaming vessel to flow out. The steaming chambers have diverging openings 18 at the top thereof and the steaming vessel has a converging portion 19 at the bottom thereof to facilitate feed entry into the steaming chambers and to converge the paddy being discharged from the steaming vessel, respectively. The drier also comprises two hot air drying units 20 in a row in succession. Each of the hot air drying units 20 comprises a hot air drying chamber 21 having a channel shaped vibratory plenum chamber 22 extending along the length of the hot air drying chamber. The plenum chamber has a feed inlet 23 at the inlet end 24 thereof, a discharge outlet 25 at the discharge end 26 thereof and an exhaust air outlet 27. The sidewalls of the plenum chamber are marked 28. The plenum chamber comprises a plurality of openings 29 along the base 30 thereof. The plenum chamber is connected to a forced hot air supply line 31 at the inlet end thereof and is supported on a hollow support structure 32 with the help of springs 32a. (Figs 1A, 5, 6 and 7). 33 is an electric motor mounted on supports 34 and having a driver pulley 35 mounted on the shaft 36 thereof. 37 is a driven shaft disposed parallel to the motor shaft and rotatably mounted on a pair of spaced apart upright members 38. 39 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 40. 41 is a cam integrally formed on the driven shaft 37. A cam follower comprising a first bearing 42 is disposed over the cam. 43 is a crosspin rigidly connected across a bracket 44 which in turn is connected across the support structure. 45 is a second bearing mounted on the crosspin and coupled to the first bearing. The support structure comprises an access window 46 (Figs 5, 8, 9, 10 and 11). The hot air drying unit also comprises a temperature conditioner vessel 47 having an open top 48 and a conical bottom 49. The conical bottom has a discharge line 50 provided with a control valve 51. A hollow central tube 52 is located vertically at the centre of the vessel. The central tube has a hot air inlet 52 at the top thereof connected to a forced hot air supply (not shown) and a plurality of hot air distributor arms 53 projecting radially from the lower end thereof. Each of the distributor arms comprises a pair of angular members 54 disposed one above the other in spaced apart relationship and fixed together with spaced apart ribs 55. The space between the angular members is marked 56 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. (Figs 1A, 12, 13, 14 and 15). 57 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 1A). 58 is an endless conveyor horizontally linearly movably disposed below the temperature conditioner vessel of the second hot air drying unit. The endless conveyor has a feed inlet end 59 and a discharge end 60. The discharge line of the temperature conditioner of the second hot air drying unit is disposed directly above the feed inlet end of the endless conveyor. The discharge passage of the steaming vessel opens into the feed inlet of the plenum chamber of the hot air drying chamber of the first hot air drying unit (Fig 1A).
During working of the drier of the invention, cleaned paddy (not shown) is continuously fed into the steaming vessel 2 via the feed inlet passage 5. Steam (not shown) is injected into the perforated steaming chambers 3 of the steaming vessel via steam control valve 13 and perforated steam injector tubes 8. Steam is also injected into the steam jacket via steam control valve 13 and steam inlet passage 12. The paddy feed rate and steam flow rate into the steaming vessel and paddy discharge rate from the steaming vessel are controlled by the PLC through the respective valves so as to allow a residence time for the paddy mass within the steaming chambers and allow the paddy to be continuously wetted and discharged. Steam being injected through the perforations 9 of the steam injector tubes 8 flow through the paddy mass radially outwardly and steam being injected into the steam jacket 4 pass through the paddy mass radially inwardly through the perforations 7 of the perforated steaming chambers 3 and ensure uniform steaming of the paddy in the steaming chambers across the entire height of the paddy mass. The steam wet paddy is continuously fed into the plenum chamber of the first hot air drying unit 20 via the feed inlet 23 at the inlet end 24 thereof.
During operation of the first hot air drying unit, the motor shaft 36 rotates and transmits the drive to the driven shaft 37 via the driver pulley 35, driven pulley 39 and belt 40 and cause the driven shaft to rotate. Due to rotation of the driven shaft, the first bearing 42 describes a smooth and gentle up and down rotational movement over the cam 41 of the driven shaft resembling motion along a smooth curvature or a sinewave in the forward direction. As a result, the second bearing 45 along with crosspin 43, bracket 44, hollow support structure 32 and plenum chamber 22 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 30 of the plenum chamber and forms a bed of paddy. Hot air at 70 to 80°C is forced through the openings 29 at the base of the plenum chamber via the hot air supply line 31 to lift 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 gr^in 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 very effectively and the grains are uniformly dried very fast to a moisture content of 16 to 18% WB. The hot air is let out into the atmosphere via the exhaust air outlet 27 of the hot air drying unit. The sidewalls 28 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 25 of the first hot air drying unit is continuously fed into the temperature conditioner vessel 47 of the first hot air drying unit via the rsepective bucket elevator 57 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
47 via the inlet 52 thereof. The hot air travels down in the central tube 52 and to the air distributor arms 53. The hot air is distributed across the entire paddy mass in the vessel through the space 56 between the angular members 54 of each of the distributor arms 53. 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
48 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 51 at the bottom of the vessel. Paddy dried at 70 to 80°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 feed inlet of the second hot air drying unit and dried and temperature conditioned with hot air therein. Drying and temperature conditioning of the paddy in the second hot air drying unit is 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 60 to 70°C and 45 to 50°C, respectively so as to reduce the moisture content of the paddy to 12 to 14% WB. The dried paddy being finally discharged from the temperature conditioner vessel of the second hot air drying unit falls on the conveyor 58 and is carried on the conveyor 58 for milling and polishing. In the drier IB as illustrated in Fig IB of the accompanying drawings cleaned paddy is directly dried in two stages to the equilibrium level of drying in the two hot air drying units thereof as described earlier.
According to the invention cleaned paddy, optionally wetted with steam, preferably uniformly continuously steam wetted 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. Therefore, there is substantial cost benefit in terms of drier cost and saving in thermal energy requirement for drying. Due to the continuous drying of the paddy with or without steam wetting, 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. The invention is basically in uniformly continuously drying optionally steam cooked paddy in stages with the different temperatures and in the temperature conditioning of the paddy at each stage. We have found that two hot air drying units are optimal to achieve the equilibrium level of drying of the paddy. However, there can be more than two hot air drying units with appropriate hot air temperature distribution. The construction and configuration of the hot air drying units can be different. The construction and configuration of the temperature conditioner vessel can be different. 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 configuration and construction of the automated steam wetting vessel can be different. The feed rate metering device and the discharge rate metering device need not be rotary valves. Instead of PLC, any other logic control can be used to control the feed rate and discharge rate of the paddy and to control the steam flow rate. The number of steaming chambers can vary. Variations in the construction and configuration of the invention which are obvious to a person 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 raw paddy uniformly continuously, the method comprising drying a bed of cleaned paddy to a moisture content of 12 to 14% WB (Wet Basis) with hot air in two 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 70 to 80°C and temperature conditioning the paddy with hot air at 40 to 45°C to bring down the moisture content of the paddy to 16 to 18 % WB and the second stage comprising forcing hot air through the bed of paddy at 60 to 70°C and temperature conditioning the paddy with hot air at 45 to 50°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 cleaned paddy is uniformly continuously steam wetted prior to drying.
3. The method as claimed in claim 2, wherein the cleaned paddy is uniformly continuously steam wetted in an automated steaming vessel by automatically controlling the feed rate of the paddy into the steaming vessel and the discharge rate of the paddy from the steaming vessel and by automatically controlling the steam feed rate into the steaming vessel and by simultaneously injecting steam through the center of the paddy mass radially outwardly and by injecting steam from the periphery of the paddy mass radially inwardly along the entire height of the paddy mass.
4. The method as claimed in anyone of claims 1 to 3, 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.
5. The method as claimed in claim 4, wherein the paddy is temperature conditioned by forcing hot air through the paddy uniformly.
6. A drier for drying cleaned paddy uniformly continuously, the drier comprising two 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 line 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 second hot air drying unit, the endless conveyor having a feed end and a discharge end, the discharge line of the temperature conditioner of the second hot air drying unit being disposed directly above the feed end of the endless conveyor, the discharge line 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, the hot air forced through the hot air drying chamber of the first and second hot air drying units being at 70 - 80°C and 60 - 70°C, respectively and the hot air forced through the respective temperature conditioner vessels being at 40 - 45°C and 45 - 50°C, respectively.
7, The drier as claimed in claim 6, which comprises an automated steaming vessel for uniformly continuously steam wetting the cleaned paddy prior to drying.
8. The drier as claimed in claim 7, wherein the automated steaming vessel comprises a plurality of spaced apart perforated steaming chambers surrounded by a steam jacket in spaced apart relationship therewith and connected to a paddy inlet passage at the top thereof and to a paddy discharge passage at the bottom thereof, each of the perforated steaming chambers being provided with a centrally located perforated steam injector tube, the paddy inlet passage being provided with a feed rate metering device and the paddy discharge passage being provided with a discharge rate metering device, the steam jacket being provided with a steam inlet passage, the steam inlet passage and the steam injector tubes being connected to a steam source through a steam control valve, the feed rate metering device and the discharge rate metering device and the steam control valve being connected to a logic control automatically to control the paddy feed rate through the paddy inlet passage and paddy discharge rate through the paddy discharge passage and steam flow rate through the steam control valve.
9. The drier as claimed in claim 8, wherein the logic control is a Programmable Logic Control (PLC).
10. The drier as claimed in claim 8 or 9, wherein the steam jacket is provided with an inspection window.
11. The drier as claimed in any one of claims 8 to 10, wherein the steaming chambers have diverging openings at the top thereof and the steaming vessel has a converging portion at the bottom thereof.
12. The drier as claimed in anyone of claims 6 to 11, 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.
13. The drier as claimed in claim 12, wherein the cam is integrally formed on the driven shaft.
14. The drier as claimed in claim 12 or 13, 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.
15. The drier as claimed in any one of claims 6 to 14, wherein the support structure comprises an access window.
16. The drier as claimed in any one of claims 6 to 15, wherein the temperature conditioner vessel is cylindrical shaped.
17. The drier as claimed in anyone of claims 6 to 16, 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.