Indian Patents. 264428:"A METHOD FOR CONTINUOUS DRYING OF RICE"

Title of Invention	"A METHOD FOR CONTINUOUS DRYING OF RICE"
Abstract	A method for continuously drying rice, involving a process for pre-cleaning the rice and drying with warm air, wherein, after pre-cleaning, the rice is dried to a moisture content of 13% in a fluidized bed by heating the rice to a temperature of 50 to 55°C with warm air and cooled slowly to ambient temperature after drying.

Full Text	The invention relates to a method for continuously drying rice, in particular paddy rice, and to a device for continuously drying rice. Freshly harvested rice has an initial moisture of more than 20%, which must be reduced to a storage moisture of approx. 14%. The crudely pre-cleaned rice (paddy) is initially placed in preliminary drier cells, and subsequently dried by mechanical driers. Drying takes place primarify in . several passes in roof driers exposed to air heated to 50-60°C (e.g., according to WO 98/45656). There a conditioning time of up to 12 hours between each pass. As in the case of tower driers, only a limited degree of drying of up to 2% is possible. A conditioning period of at least 2 hours is required between the individual passes to achieve a temperature balance between the grain and shell. The necessary mechanical transportation processes increase crack formation. Static drying in silos or halls requires large surface areas, since the layer thickness of the rice to be dried is limited (approx. 80 to 100 cm). Drying takes place non-uniformly from the inside out given the arrangement of the ventilation equipment, and cannot be readily controlled, since there is no actual uniform distribution of air. The time required is also high. According to DE-A-2926256, a procedure for drying grain involves heating fresh air and passing it over the grain, during which the fresh air is preliminarily also cooled to reduce its moisture content. DE-A-2947759 discloses a similar solution. DE-A-2938620 shows a continuous-flow drier with a cylindrical drying zone, which has perforated sheets. This is followed by an identically configured cooling zone. DE-A-4119787 shows a conditioning device for bulk vegetable goods with a closed, tunnel-like conditioning stajtion through which a transport path leads, carrying the bulk material. The bulk material is here exposed to a gaseous heat carrier. Such conveyors can have porous surfaces through which warm or cold gases can stream to heat or cool grains, and reduce moisture content (WO 01/02786).DE-A-19806951 discloses a device for puffing granular goods, in which the material is subjected to batchwise heating in a fluidized bed chamber. EP-A-1099380 discloses a method for manufacturing heat-treated grain, wherein the heat treatment takes place by means of a gas stream in an annular fluidized bed. The gas stream has different velocity components.In JP-A-58056650, raw rice with approx. 18% moisture content is heated with warm air at approx. 140°C for about 30 minutes. Drying can take place in a tumbler drier or fluidized bed, wherein the starch is thermally affected. The dried raw rice is then directly shelled or shelled and cooled, if shelling is necessary to achieve a readily boilable, unpolished rice.Dried and pre-cleaned rise can then be stored like any other grain, even up to the time it is processed.The object of the invention is now to at least partially eliminate the described disadvantages to prior art, and develop a method for continuously drying rice, in particular of paddy. The object is achieved with the features in claim 1, and advantageous embodiments are disclosed in the subclaims.The invention is based on the assumption that rice (paddy) could behave similarly to a polymer under certain moisture and temperature conditions, since a glassy or rubbery state is possible, depending on the constellation of these conditions. At a low temperature (down to roughly^- room temperature) and an initial moisture exceeding 20%, paddy is glassy, but goes over into a rubbery state as temperature increases. This state can only be obtained via temperature maintenance and simultaneous dehumidification. When cooled, the paddy again reaches a glassy state. This knowledge can now be used to dry paddy in a continuous process, while still avoiding grain breakage. To this end, the paddy is heated to approx. 50 to 55°C, dried to approx. 14% moisture content, and then cooled to ambient temperature.Heating and drying preferably takes place in a fluidized bed. The inner pressure in the rice grain is increased in the warm fluidized bed via the evaporation of water. Pressure compensation between the grain and environment allows the moisture to exit the grain.Treatment in the fluidized bed can take place in one, two or more stages. During two-stage drying, there is no intermediate conditioning, and the second stage is preferably a combined drying/cooling process.During the supply of hot vapor, the drying process can also begin at a higher temperature (up to approx. 120°C) given a high moisture content of the paddy.Another object is to provide a device for continuously drying rice, in particular one suited for executing the process according to the invention. Use is here made of known separators and selecting machines for precleaning, and at least one fluidized bed apparatus for drying. In one variant, two fluidized bed apparatuses can be arranged in sequence, wherein the second apparatus also contains a cooler (precooler) in addition to a drier.The invention will be described in greater detail below in two exemplary embodiments based on a drawing. The drawing shows a simplified diagram in the single figure.The supplied raw rice passes from a depot 1 into a drum sieve 2, where very large contaminants are removed. This is followed by another precleaning step in a separator/classifier 3 to remove rocks, sand, and light contaminants, such as paber, straw or loose shells. The pre-cleaning device is configured as a function of how contaminated the supplied raw rice is. It is advantageous to largely separate loose contaminants and admixtures from the raw rice prior to further treatment.After pre-cleaning and brief intermediate storage in another depot 4, the rice arrives at a first fluidized bed apparatus 5, in which the one rice layer is traversed from below by warm air, heated to approx. 50°C, and dried by about 3-4% moisture. The rice then passes directly into a second fluidizedbed apparatus 6, in which a temperature of approx. 50°C is maintained, and drying by another 3-4% moisture takes place. In the last third of this second fluidized bed apparatus 6, the rice is cooled to approx. 40°C.The paddy then passes into a conditioning container 7, where it is slowly (approx. 20 hours) cooled to ambient temperature, loose another 1% moisture in the process. The tempering/conditioning time can be reduced via the suitable means.As an alternative to tempering, the rice can be cooled (with or without pre-cooling in the second fluidized bed apparatus 6) faster in a countercurrent cooler, e.g., within approx. 15 minutes.There was a clear reduction in grain breakage at drastically reduced drying times relative to conventional methods. The system is also less expensive to maintain, and the low drying times make it possible to store the raw rice faster, or obtain more rice at harvest time.In another embodiment, very moist raw rice (e.g., with an initial moisture of approx. 37%) is dried in a roof drier with fluidized bed in several stages. The first stage can already take place with hot vapor at approx. 120°C over 3 hours. The moisture is here reduced to approx. 20-22%. In additional 1 hour stages, drying continues given an incrementally restricted vapor supply, wherein the air or vapor temperature is also incrementally reduced down to 50°C. This results in a moisture content of approx. 13%. In a final step, the rice is cooled to ambient temperature within a half an hour," wherein no more vapor is supplied any more. A moisture content of approx. 12.5% can be achieved. REFERENCE LIST 1 Depot 2 Drum sieve 3 Separator 4 Depot 5 Fluidized bed apparatus 6 Fluidized bed apparatus 7 Conditioning container WE CLAIM: 1. A method for continuously drying rice, involving a process for pre-cleaning the rice and drying with warm air, wherein, after pre-cleaning, the rice is dried to a moisture content of 13% in a fluidized bed by heating the rice to a temperature of 50 to 55°C with warm air and cooled slowly to ambient temperature after drying. 2. The method as claimed in claim 1, wherein drying in the fluidized bed takes place in a single stage. 3. The method as claimed in claim 1, wherein drying in the fluidized bed takes place in two stages. 4. The method as claimed in claim 1, wherein drying in the fluidized bed takes place in more than two stages. 5. The method as claimed in claim 3, wherein the fluidized bed in the second stage involves drying and pre-cooling. 6. The method as claimed in claim 5, wherein pre-cooling takes place in the last third of the second stage. 7. The method as claimed in one of claims 1 to 6, wherein the rice is dried at a temperature of 50 to 55°C to a moisture content of 13%, and cooled in a countercurrent to ambient temperature after drying. 8. The method as claimed in claim 1 or 4, wherein drying takes place in several temperature stages with the addition of hot steam. 9. The method as claimed in claim 8, wherein hot steam with a temperature of 120°C is added in a first stage, and its temperature is incrementally reduced to 50°C in the subsequent stages. 10. The method as claimed in claim 9, wherein the hot steam supply is baffled incrementally. 11. A device for continuously drying rice, in particular of paddy, involving a process for pre-cleaning the rice and means for drying with warm air used in implementing a process as claimed in claims 1 to 10, wherein the means for drying encompasses at least one fluidized bed apparatus (5,6). 12. The device as claimed in claim 11, wherein two consecutively arranged fluidized bed apparatuses (5,6) are provided. 13. The device as claimed in claim 12, wherein the second fluidized bed apparatus (6) comprises a drying area and a cooling area. 14. The device as claimed in claims 11 to 13, wherein a cooling stage is situated after the at least one fluidized bed apparatus (5,6). 15. The device as claimed in claim 14, wherein the cooling stage is integrated in the fluidized bed apparatus (5,6). 16. The device as claimed in at least one of claims 11 to 15, wherein the fluidized bed apparatus is a roof dryer.

Full Text

The invention relates to a method for continuously drying rice, in particular paddy rice, and to a device for continuously drying rice.
Freshly harvested rice has an initial moisture of more than 20%, which must be reduced to a storage moisture of approx. 14%. The crudely pre-cleaned rice (paddy) is initially placed in preliminary drier cells, and subsequently dried by mechanical driers. Drying takes place primarify in . several passes in roof driers exposed to air heated to 50-60°C (e.g., according to WO 98/45656). There a conditioning time of up to 12 hours between each pass. As in the case of tower driers, only a limited degree of drying of up to 2% is possible. A conditioning period of at least 2 hours is required between the individual passes to achieve a temperature balance between the grain and shell. The necessary mechanical transportation processes increase crack formation.
Static drying in silos or halls requires large surface areas, since the layer thickness of the rice to be dried is limited (approx. 80 to 100 cm). Drying takes place non-uniformly from the inside out given the arrangement of the ventilation equipment, and cannot be readily controlled, since there is no actual uniform distribution of air. The time required is also high.
According to DE-A-2926256, a procedure for drying grain involves heating fresh air and passing it over the grain, during which the fresh air is preliminarily also cooled to reduce its moisture content. DE-A-2947759 discloses a similar solution.
DE-A-2938620 shows a continuous-flow drier with a cylindrical drying zone, which has perforated sheets. This is followed by an identically configured cooling zone. DE-A-4119787 shows a conditioning device for bulk vegetable goods with a closed, tunnel-like conditioning stajtion through which a transport path leads, carrying the bulk material. The bulk material is here exposed to a gaseous heat carrier.
Such conveyors can have porous surfaces through which warm or cold gases can stream to heat or cool grains, and reduce moisture content (WO 01/02786).DE-A-19806951 discloses a device for puffing granular goods, in which the material is subjected to batchwise heating in a fluidized bed chamber. EP-A-1099380 discloses a method for manufacturing heat-treated grain, wherein the heat treatment takes place by means of a gas stream in an annular fluidized bed. The gas stream has different velocity components.In JP-A-58056650, raw rice with approx. 18% moisture content is heated with warm air at approx. 140°C for about 30 minutes. Drying can take place in a tumbler drier or fluidized bed, wherein the starch is thermally affected. The dried raw rice is then directly shelled or shelled and cooled, if shelling is necessary to achieve a readily boilable, unpolished rice.Dried and pre-cleaned rise can then be stored like any other grain, even up to the time it is processed.The object of the invention is now to at least partially eliminate the described disadvantages to prior art, and develop a method for continuously drying rice, in particular of paddy. The object is achieved with the features in claim 1, and advantageous embodiments are disclosed in the subclaims.The invention is based on the assumption that rice (paddy) could behave similarly to a polymer under certain moisture and temperature conditions, since a glassy or rubbery state is possible, depending on the constellation of these conditions. At a low temperature (down to roughly^- room temperature) and an initial moisture exceeding 20%, paddy is glassy, but goes over into a rubbery state as temperature increases. This state can only be obtained via temperature maintenance and simultaneous dehumidification. When cooled, the paddy again reaches a glassy state. This knowledge can now be used to dry paddy in a continuous process, while still avoiding grain breakage. To this end, the paddy is heated to approx. 50 to 55°C, dried to approx. 14% moisture content, and then cooled to ambient temperature.Heating and drying preferably takes place in a fluidized bed. The inner pressure in the rice grain is increased in the warm fluidized bed via the evaporation of water. Pressure compensation between the grain and environment allows the moisture to exit the grain.Treatment in the fluidized bed can take place in one, two or more stages. During two-stage drying, there is no intermediate conditioning, and the second stage is preferably a combined drying/cooling process.During the supply of hot vapor, the drying process can also begin at a higher temperature (up to approx. 120°C) given a high moisture content of the paddy.Another object is to provide a device for continuously drying rice, in particular one suited for executing the process according to the invention. Use is here made of known separators and selecting machines for precleaning, and at least one fluidized bed apparatus for drying. In one variant, two fluidized bed apparatuses can be arranged in sequence, wherein the second apparatus also contains a cooler (precooler) in addition to a drier.The invention will be described in greater detail below in two exemplary embodiments based on a drawing. The drawing shows a simplified diagram in the single figure.The supplied raw rice passes from a depot 1 into a drum sieve 2, where very large contaminants are removed. This is followed by another precleaning step in a separator/classifier 3 to remove rocks, sand, and light contaminants, such as paber, straw or loose shells. The pre-cleaning device is configured as a function of how contaminated the supplied raw rice is. It is advantageous to largely separate loose contaminants and admixtures from the raw rice prior to further treatment.After pre-cleaning and brief intermediate storage in another depot 4, the rice arrives at a first fluidized bed apparatus 5, in which the one rice layer is traversed from below by warm air, heated to approx. 50°C, and dried by about 3-4% moisture. The rice then passes directly into a second fluidizedbed apparatus 6, in which a temperature of approx. 50°C is maintained, and drying by another 3-4% moisture takes place. In the last third of this second fluidized bed apparatus 6, the rice is cooled to approx. 40°C.The paddy then passes into a conditioning container 7, where it is slowly (approx. 20 hours) cooled to ambient temperature, loose another 1% moisture in the process. The tempering/conditioning time can be reduced via the suitable means.As an alternative to tempering, the rice can be cooled (with or without pre-cooling in the second fluidized bed apparatus 6) faster in a countercurrent cooler, e.g., within approx. 15 minutes.There was a clear reduction in grain breakage at drastically reduced drying times relative to conventional methods. The system is also less expensive to maintain, and the low drying times make it possible to store the raw rice faster, or obtain more rice at harvest time.In another embodiment, very moist raw rice (e.g., with an initial moisture of approx. 37%) is dried in a roof drier with fluidized bed in several stages. The first stage can already take place with hot vapor at approx. 120°C over 3 hours. The moisture is here reduced to approx. 20-22%. In additional 1 hour stages, drying continues given an incrementally restricted vapor supply, wherein the air or vapor temperature is also incrementally reduced down to 50°C. This results in a moisture content of approx. 13%. In a final step, the rice is cooled to ambient temperature within a half an hour," wherein no more vapor is supplied any more. A moisture content of approx. 12.5% can be achieved.
REFERENCE LIST
1 Depot
2 Drum sieve
3 Separator
4 Depot
5 Fluidized bed apparatus
6 Fluidized bed apparatus
7 Conditioning container

WE CLAIM:
1. A method for continuously drying rice, involving a process for pre-cleaning the rice and drying with warm air, wherein, after pre-cleaning, the rice is dried to a moisture content of 13% in a fluidized bed by heating the rice to a temperature of 50 to 55°C with warm air and cooled slowly to ambient temperature after drying.
2. The method as claimed in claim 1, wherein drying in the fluidized bed takes place in a single stage.
3. The method as claimed in claim 1, wherein drying in the fluidized bed takes place in two stages.
4. The method as claimed in claim 1, wherein drying in the fluidized bed takes place in more than two stages.
5. The method as claimed in claim 3, wherein the fluidized bed in the second stage involves drying and pre-cooling.
6. The method as claimed in claim 5, wherein pre-cooling takes place in the last third of the second stage.
7. The method as claimed in one of claims 1 to 6, wherein the rice is dried at a temperature of 50 to 55°C to a moisture content of 13%, and cooled in a countercurrent to ambient temperature after drying.
8. The method as claimed in claim 1 or 4, wherein drying takes place in several temperature stages with the addition of hot steam.
9. The method as claimed in claim 8, wherein hot steam with a temperature of 120°C is added in a first stage, and its temperature is incrementally reduced to 50°C in the subsequent stages.
10. The method as claimed in claim 9, wherein the hot steam supply is baffled incrementally.
11. A device for continuously drying rice, in particular of paddy, involving a process for pre-cleaning the rice and means for drying with warm air used in implementing a process as claimed in claims 1 to 10, wherein the means for drying encompasses at least one fluidized bed apparatus (5,6).
12. The device as claimed in claim 11, wherein two consecutively arranged fluidized bed apparatuses (5,6) are provided.
13. The device as claimed in claim 12, wherein the second fluidized bed apparatus (6) comprises a drying area and a cooling area.
14. The device as claimed in claims 11 to 13, wherein a cooling stage is situated after the at least one fluidized bed apparatus (5,6).
15. The device as claimed in claim 14, wherein the cooling stage is integrated in the fluidized bed apparatus (5,6).
16. The device as claimed in at least one of claims 11 to 15, wherein the fluidized bed apparatus is a roof dryer.

Documents:

710-DELNP-2006-Abstract-(27-09-2011).pdf

710-DELNP-2006-Abstract-031214.pdf

710-delnp-2006-abstract.pdf

710-DELNP-2006-Amended Pages Of Specification-031214.pdf

710-DELNP-2006-Claims-(27-09-2011).pdf

710-DELNP-2006-Claims-031214.pdf

710-delnp-2006-claims.pdf

710-DELNP-2006-Correspondence Others-(27-09-2011).pdf

710-DELNP-2006-Correspondence-191214.pdf

710-delnp-2006-correspondence-others.pdf

710-DELNP-2006-Description (Complete)-(27-09-2011).pdf

710-delnp-2006-description (complete).pdf

710-DELNP-2006-Drawings-(27-09-2011).pdf

710-delnp-2006-drawings.pdf

710-DELNP-2006-Form 2(Title Page)-031214.pdf

710-delnp-2006-form-1.pdf

710-delnp-2006-form-2.pdf

710-DELNP-2006-Form-3-(27-09-2011).pdf

710-delnp-2006-form-3.pdf

710-delnp-2006-form-5.pdf

710-DELNP-2006-GPA-(27-09-2011).pdf

710-delnp-2006-gpa.pdf

710-delnp-2006-pct-210.pdf

710-delnp-2006-pct-301.pdf

710-delnp-2006-pct-306.pdf

710-delnp-2006-pct-308.pdf

710-delnp-2006-pct-332.pdf

710-DELNP-2006-Petition-137-(27-09-2011).pdf

710-DELNP-2006-Power of Attorney-191214.pdf

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Patent Number

264428

Indian Patent Application Number

710/DELNP/2006

PG Journal Number

01/2015

Publication Date

02-Jan-2015

Grant Date

29-Dec-2014

Date of Filing

13-Feb-2006

Name of Patentee

BUHLER AG.

Applicant Address

BAHNHOFSTRASSE, CH-9240 UZWIL, SWITZERLAND.

Inventors:

#	Inventor's Name	Inventor's Address
1	LEO EISENRING	CALLE 127, A# 28-48, CASA 3, BOGOTA, COLUMBIA
2	ENRIQUE NINO PEREZ	DIAGONAL 34C# 15-75, NANZANA 22, BOGOTA, COLUMBIA.

PCT International Classification Number

F26B 3/08

PCT International Application Number

PCT/CH2003/000558

PCT International Filing date

2003-08-19

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	PCT/CH2003/000558	2003-08-19	Switzerland