GB1566163A - Drying of crops - Google Patents

Drying of crops Download PDF

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Publication number
GB1566163A
GB1566163A GB5223377A GB5223377A GB1566163A GB 1566163 A GB1566163 A GB 1566163A GB 5223377 A GB5223377 A GB 5223377A GB 5223377 A GB5223377 A GB 5223377A GB 1566163 A GB1566163 A GB 1566163A
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GB
United Kingdom
Prior art keywords
crop
chamber
baffles
drier
zone
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB5223377A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BURTON FINANCE CO Ltd
Original Assignee
BURTON FINANCE CO Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BURTON FINANCE CO Ltd filed Critical BURTON FINANCE CO Ltd
Publication of GB1566163A publication Critical patent/GB1566163A/en
Expired legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
    • A24B3/00—Preparing tobacco in the factory
    • A24B3/04—Humidifying or drying tobacco bunches or cut tobacco
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/02—Dehydrating; Subsequent reconstitution
    • A23B7/0205—Dehydrating; Subsequent reconstitution by contact of the material with fluids, e.g. drying gas or extracting liquids
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00—Drying solid materials or objects by processes involving the application of heat
    • F26B3/02—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air
    • F26B3/06—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried
    • F26B3/08—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried so as to loosen them, e.g. to form a fluidised bed
    • F26B3/082—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried so as to loosen them, e.g. to form a fluidised bed arrangements of devices for distributing fluidising gas, e.g. grids, nozzles

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Microbiology (AREA)
  • General Chemical & Material Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Zoology (AREA)
  • Food Science & Technology (AREA)
  • Polymers & Plastics (AREA)
  • Drying Of Solid Materials (AREA)

Description

(54) IMRPOVEMENTS IN OR RELATING TO THE DRYING OF CROPS (71) We, BURTON FINANCE COM PANY LIMITED, a company organised under the laws of the Bahamas. of 2nd Floor, Bitco Building. East Street, Nassau, Bahamas, and AUSTIN BIRNEY, a British subject, of 51 Brinkburn Avenue, Darlington, Durham, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement : This invention relates to crop driers and in particular to driers for the processing of tea There are many crop driers commercially available, some of which are more specifically designed to cope with a particular crop such as tea or tobacco whilst yet others are more specifically directed for use with vegetable crops.
In general, crop driers take one of three main forms that is to say tunnels, cabinets or rotary drums. The cabinet type drier is generally of small throughput and is used to provide high quality limited production produce. The rotary drum is generally intended for a higher throughput of less heat sensitive crop such as the processing of animal feed stuffs. The third type, namely the tunnel drier is more widely used than any other and takes on a variety of designs as a consequence.
It is particularly with the tunnel-type drier that this invention is concerned.
It is an object of the invention to provide a more efficient tunnel-type drier which will have a minimum of moving parts resulting in avoidance of tray pile-up and other breakdown problems; more control over temperatures and satisfactory high throughput.
According to the invention there is provided a crop drier comprising an elongated casing provided with a plurality of substantiaIly vertical partitions disposed along the casing and defining between themselves and casing several chambers, in the lower aad upper zones respectively of each cham bef, a set of adjustable baffles adapted to regulate rate and direction of flow of an airstream originating in the lower zone of each chamber and discharging above the upper zone of each or any chamber, a grid platform located in the upper zone of each chamber disposed above the upper baffles and adapted to receive and retain crops to be or being dried; (optionally a blowhole suppression mechanism associated with the grid of platform and adapted to prevent or reduce formation of blowholes in the crop being processed in the rising airstream; the suppression mechanism including link rods carried on bearings adapted to allow the platform or grid to vibrate in at least one horizontal plane) an inlet port at one end of the casing for raw or unprocessed crop and a discharge port at or towards the other end of the casing for the release of processed crop.
According to a feature of the invention, means are provided for recycling hot air from the later chambers to the lower zone of each or any chamber so regaining otherwise waste heat.
The invention also provides a method of drying a crop including charging the moist crop to the upper surface of a grid platform in a first chamber of a crop drier of the present invention, arranging the lower baffles to direct a stream of hot air from below the grid platform through the slots in the grid platform with a sufficient velocity effectively to 'fluidise' the crop being dried; adjusting the upper baffles in a manner to cause the fluidised crop to tend to progress from the first chamber towards the second and later chambers as the moisture content decreases.
In one aspect of the invention the fluidised crop may be retained at will in any given chamber by adjustment of the upper baffles to direct the airstream in that chamber in a sense opposite to the airstream ill a previous chamber so as to arrest the normal progression from inlet to discharge port.
A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a schematic cross-section through a crop drier, Figure 2 is a plan view of a grid platform, and Figure 3 is a cross-section through the grid platform.
Referring to Figure 1 5 indicates a casing defining the outer walls of a crop drier and 6 indicates internal vertically disposed partitioning defining a plurality of crop drying chambers 7.
In the lower zone of the chamber 7 are disposed a series of baffles 8 which regulate airflow as -indicated by arrows 9 and 10 from a plenum chamber 11 towards baffles 12 in the upper zone of chamber 7 through plate form grids 13 and blowhole suppressor mechanism 14 into fluidised zone 15 where the crop being dried (not shown) will tend to be agitated in the direction of arrows 16 as a result of the angle of adjustment of baffles 12 and the general configuration of the apparatus as a whole. The grids 13 are suspended on links 17 and bearings 17(a).
By altering the velocity of airstream 9 and 10 by lower baffles 8 and also by baffles 12, the height of the fluidised zone above the grids 13 -in - zones 15 can be regulated so that the partially dried crop from one zone will move forward into the next adjacent chamber 7 as indicated by the direction of the arrows 16.
It will be observed from the drawings that in the final chamber 18(a) the arrow 16 lies from right to left as viewed by the observer in conformity with the placing of the baffles 12(a) in chamber 18(a) so that the crop can be actually held in the fluidised zone 15 above chamber 18(a) in a direction contrary to the flow of the remaining crop as indicated by the remaining arrows 16 in the various proceeding chambers.
When desired, the baffles 12(a) may be rotated so that the airflow indicated by arrow 16 above chamber 18(a) will lie in the opposite sense, that is from left to right and consequently the crop in fluidised zone 15(a) above chamber 18(a) will then be moved to the right and into the discharge throat 19 leading from the crop drier.
In the upper lefthand part of the apparatus as shown in Figure 1 there is schematically depicted at 20, a conveyor belt with a vibrator feeder and, if required, a rotary ball breaker to ensure that incoming crop to the drier is sufficiently particulate to permit fluidisation when discharged into the fluidising zone 15.
Referring now to Figure 2 of the drawings, the grid platform 13 is illustrated in plan view. The grid platform 13 comprises an accurately machined metal plate wherein slots 21 are cut by means, for example, of a plurality of saws stationed on a spindle, the saws having an effective radius of 21i inches (6.35 mm) from the spindle rotational axis.
Likewise, the width and length of the slots 21 are machined to close tolerances but the actual dimensions in width and length can be varied depending on the predominant nature of the crop to be dried.
The slots 21 when viewed in side elevation as shown in Figure 3 present a cambered or chamfered lower profile which materially assists in the concentration of airflow through grid slots 21 giving rise to an elongated conical rising air mass above each slot 21.
This particular configuration appears to assist materially if it is not absolutely essential to proper fluidisation in the bed of the crop resting upon the grid platform 13.
The operation of the apparatus will be readily apparent to those skilled in the art from a reading of the above description together with the drawing indicating one presently used example of the invention.
WHAT WE CLAIM IS:- 1. A crop drier comprising an elongated casing provided with a plurality of substantially vertical partitions disposed along the casing and defining between them and the casing several chambers, in the lower and upper zones respectively of each chamber, a set of adjustable baffles adapted to regulate rate and direction of flow of an airstream originating in the lower zone of each chamber and discharging above the upper zone of each or any chamber; a grid platform in the upper zone of each chamber disposed above the upper baffles and adapted to receive and retain crops to be or being dried; an inlet port at one end of the casing for raw or unprocessed crop and a discharge port at or towards the other end of the casing for the release of processed crop.
2. A crop drier as claimed in claim 1 wherein the adjustable baffles are louvre-type slats.
3. A crop drier as claimed in claim 1 or claim 2 wherein the grid platform comprises a metal plate having slots machined therein.
4. A crop drier as claimed in any one of claims 1 to 3 wherein the slots are machined accurately to relatively close tolerance but the actual dimensions in width and length are determined by the nature of the crop to be dried.
5. A crop drier as claimed in any one of claims 1 to 4 wherein the slots viewed in side elevation present a cambered or chamfered lower profile.
6. A crop drier as claimed in any one of claims 1 to 5 wherein a blowhole suppression mechanism is provided which comprises link rods and bearing adapted to per
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (12)

**WARNING** start of CLMS field may overlap end of DESC **. Figure 1 is a schematic cross-section through a crop drier, Figure 2 is a plan view of a grid platform, and Figure 3 is a cross-section through the grid platform. Referring to Figure 1 5 indicates a casing defining the outer walls of a crop drier and 6 indicates internal vertically disposed partitioning defining a plurality of crop drying chambers 7. In the lower zone of the chamber 7 are disposed a series of baffles 8 which regulate airflow as -indicated by arrows 9 and 10 from a plenum chamber 11 towards baffles 12 in the upper zone of chamber 7 through plate form grids 13 and blowhole suppressor mechanism 14 into fluidised zone 15 where the crop being dried (not shown) will tend to be agitated in the direction of arrows 16 as a result of the angle of adjustment of baffles 12 and the general configuration of the apparatus as a whole. The grids 13 are suspended on links 17 and bearings 17(a). By altering the velocity of airstream 9 and 10 by lower baffles 8 and also by baffles 12, the height of the fluidised zone above the grids 13 -in - zones 15 can be regulated so that the partially dried crop from one zone will move forward into the next adjacent chamber 7 as indicated by the direction of the arrows 16. It will be observed from the drawings that in the final chamber 18(a) the arrow 16 lies from right to left as viewed by the observer in conformity with the placing of the baffles 12(a) in chamber 18(a) so that the crop can be actually held in the fluidised zone 15 above chamber 18(a) in a direction contrary to the flow of the remaining crop as indicated by the remaining arrows 16 in the various proceeding chambers. When desired, the baffles 12(a) may be rotated so that the airflow indicated by arrow 16 above chamber 18(a) will lie in the opposite sense, that is from left to right and consequently the crop in fluidised zone 15(a) above chamber 18(a) will then be moved to the right and into the discharge throat 19 leading from the crop drier. In the upper lefthand part of the apparatus as shown in Figure 1 there is schematically depicted at 20, a conveyor belt with a vibrator feeder and, if required, a rotary ball breaker to ensure that incoming crop to the drier is sufficiently particulate to permit fluidisation when discharged into the fluidising zone 15. Referring now to Figure 2 of the drawings, the grid platform 13 is illustrated in plan view. The grid platform 13 comprises an accurately machined metal plate wherein slots 21 are cut by means, for example, of a plurality of saws stationed on a spindle, the saws having an effective radius of 21i inches (6.35 mm) from the spindle rotational axis. Likewise, the width and length of the slots 21 are machined to close tolerances but the actual dimensions in width and length can be varied depending on the predominant nature of the crop to be dried. The slots 21 when viewed in side elevation as shown in Figure 3 present a cambered or chamfered lower profile which materially assists in the concentration of airflow through grid slots 21 giving rise to an elongated conical rising air mass above each slot 21. This particular configuration appears to assist materially if it is not absolutely essential to proper fluidisation in the bed of the crop resting upon the grid platform 13. The operation of the apparatus will be readily apparent to those skilled in the art from a reading of the above description together with the drawing indicating one presently used example of the invention. WHAT WE CLAIM IS:-
1. A crop drier comprising an elongated casing provided with a plurality of substantially vertical partitions disposed along the casing and defining between them and the casing several chambers, in the lower and upper zones respectively of each chamber, a set of adjustable baffles adapted to regulate rate and direction of flow of an airstream originating in the lower zone of each chamber and discharging above the upper zone of each or any chamber; a grid platform in the upper zone of each chamber disposed above the upper baffles and adapted to receive and retain crops to be or being dried; an inlet port at one end of the casing for raw or unprocessed crop and a discharge port at or towards the other end of the casing for the release of processed crop.
2. A crop drier as claimed in claim 1 wherein the adjustable baffles are louvre-type slats.
3. A crop drier as claimed in claim 1 or claim 2 wherein the grid platform comprises a metal plate having slots machined therein.
4. A crop drier as claimed in any one of claims 1 to 3 wherein the slots are machined accurately to relatively close tolerance but the actual dimensions in width and length are determined by the nature of the crop to be dried.
5. A crop drier as claimed in any one of claims 1 to 4 wherein the slots viewed in side elevation present a cambered or chamfered lower profile.
6. A crop drier as claimed in any one of claims 1 to 5 wherein a blowhole suppression mechanism is provided which comprises link rods and bearing adapted to per
mit the grid platform to oscillate in at least one horizontal plate.
7. A crop drier as claimed in claim 6 wherein the blowhole suppression mechanism comprises an horizontally disposed framework suspended on link rods and bearings adapted to permit the framework to oscillate in at least one horizontal plane; the framework being provided with an open spaced latticework of rods lying in an horizontal plane at a predeterminable distance above the upper surface of the grill platform.
8. A crop drier as claimed in any one of claims 1 to 7 and comprising means for recycling hot air from the exhaust port to the lower zones of each or any chamber.
9. A method of drying a crop including charging the moist crop to the upper surface of a grid platform in a first chamber of a crop drier or claimed in any one of the preceding claims; arranging the lower baffles to direct a stream of hot air from below the grid platform through the slots in the grid platform with a sufficient velocity effectively to fluidise the crop being dried; adjusting the upper baffles in a manner to cause the fluidised crop to tend to progress from the first chamber towards the second and later chambers as the moisture content in the crop decreases.
10. A method as claimed in claim 9 wherein the fluidised crop can be retained at will in any given chamber by adjustment of the upper baffles to direct the airstream in that chamber in a sense opposite to the airstream in a previous chamber so as to arrest the normal progression from the inlet to the discharge port.
11. A crop drier substantially as herein described with reference to the accompanying drawings.
12. A method of drying a crop substantially as herein described with reference to the accompanying drawings.
GB5223377A 1976-12-21 1977-12-15 Drying of crops Expired GB1566163A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
MW5176A MW5176A1 (en) 1976-12-21 1976-12-21 Fluid bed driers fluid bed driers fluid bed driers

Publications (1)

Publication Number Publication Date
GB1566163A true GB1566163A (en) 1980-04-30

Family

ID=19740660

Family Applications (1)

Application Number Title Priority Date Filing Date
GB5223377A Expired GB1566163A (en) 1976-12-21 1977-12-15 Drying of crops

Country Status (3)

Country Link
GB (1) GB1566163A (en)
KE (1) KE3125A (en)
MW (1) MW5176A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2167679A (en) * 1984-10-15 1986-06-04 Mitsubishi Metal Corp Multichamber type fluid bed reaction apparatus
WO1988001717A1 (en) * 1986-09-01 1988-03-10 Ahlströmföretagen Svenska Ab Method and apparatus for drying a particulate material such as bark
DE3790512T1 (en) * 1986-09-01 1989-10-19 Ahlstroem Foeretagen METHOD AND DEVICE FOR DRYING PARTICLE MATERIAL LIKE BORKE
GB2239305A (en) * 1989-12-23 1991-06-26 Myron Grant Hampton Drying tea

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2167679A (en) * 1984-10-15 1986-06-04 Mitsubishi Metal Corp Multichamber type fluid bed reaction apparatus
WO1988001717A1 (en) * 1986-09-01 1988-03-10 Ahlströmföretagen Svenska Ab Method and apparatus for drying a particulate material such as bark
DE3790512T1 (en) * 1986-09-01 1989-10-19 Ahlstroem Foeretagen METHOD AND DEVICE FOR DRYING PARTICLE MATERIAL LIKE BORKE
GB2239305A (en) * 1989-12-23 1991-06-26 Myron Grant Hampton Drying tea

Also Published As

Publication number Publication date
KE3125A (en) 1981-05-22
MW5176A1 (en) 1978-11-08

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PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee