GB2026668A - Conditioning Apparatus - Google Patents
Conditioning Apparatus Download PDFInfo
- Publication number
- GB2026668A GB2026668A GB7924736A GB7924736A GB2026668A GB 2026668 A GB2026668 A GB 2026668A GB 7924736 A GB7924736 A GB 7924736A GB 7924736 A GB7924736 A GB 7924736A GB 2026668 A GB2026668 A GB 2026668A
- Authority
- GB
- United Kingdom
- Prior art keywords
- distribution means
- conditioning
- chamber
- per minute
- leaf material
- 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.)
- Granted
Links
Classifications
-
- 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
- F26B3/092—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 agitating the fluidised bed, e.g. by vibrating or pulsating
- F26B3/0923—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 agitating the fluidised bed, e.g. by vibrating or pulsating by mechanical means, e.g. vibrated plate, stirrer
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Microbiology (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Drying Of Solid Materials (AREA)
Abstract
A conditioning apparatus for conditioning (drying or cooling) leaf material (tea or tobacco) comprises a conditioning chamber disposed above gas distribution means, means for supplying gaseous medium (e.g. heated air) to said chamber through said gas distribution means, said gas distribution means having a resistance to flow of gaseous medium which increases as the rate of flow through the distribution means increases, whereby when the apparatus is in use the leaf material to be conditioned is maintained in a fluidised state. The distribution means preferably comprises an apertured plate and an underlying fabric mesh and is such as to provide a pressure drop to 1 to 12 inches water gauge for a bed face velocity of gaseous medium of 150 to 250 feet per minute. The chamber may be vibrated in use, the leaf material being thus conveyed through the chamber.
Description
SPECIFICATION
Conditioning Apparatus
This invention relates to conditioning apparatus and more particularly concerns apparatus for conditioning leaf vegetable material such as tea and tobacco.
It is known to dry leaf vegetable material by means of fluid bed drying apparatus but such apparatus has a number of defects particularly as regards even distribution of the drying medium and the production of even and consistent dried product.
According to one aspect of the present invention a conditioning apparatus for conditioning leaf material comprises a conditioning chamber disposed above gas distribution means, means for supplying gaseous medium to said chamber through said gas distribution means, said gas distribution means having a resistance to flow of gaseous medium which increases as the rate of flow through the distribution means increases, whereby when the apparatus is in use the leaf material to be conditioned is maintained in a fluidised state.
Preferably the gaseous medium is air which is at a temperature and humidity to produce the desired conditioning, which may be, for example, drying or cooling.
Conveniently the air is delivered by way of a conduit which extends beneath the distribution means. if desired a series of angled deflector plates which cause a horizontal flow of air to be transferred to a vertical flow may be included. The angled plates are preferably arranged in series across the drying chamber such that deflected air from any one plate is-not interfered with by the incoming horizontal stream of air.
The distribution means is preferably such as to provide a pressure drop across the bed of 1 to 12 inches water gauge, more preferably 1 to 8 inches water gauge and most preferably 1.5 to 4 inches water gauge, for a bed face velocity (i.e. the velocity of the gaseous medium at the surface of the distribution means) of 1 50 to 250 feet per minute. Preferably the bed face velocity is 200 to 220 feet per minute and, advantageously, about 200 feet per minute.
In a particularly preferred form of the invention the distribution means comprises a metal plate having apertures therein and a mesh disposed beneath said plate. Preferably the mesh is a fine mesh fabric which is inert and temperature resistant.
In order to assist in obtaining a uniform conditioning of the leaf material it is preferred to cause the conditioning chamber to vibrate at the same time as the air is forced through the distribution means. Thus it is preferred to provide a vibration device and more preferably a vibration device which vibrates linearly and which can be adjusted relative to the chamber in order to cause said chamber to vibrate in one of a number of possible directions. The chosen direction will usually be in a plane which is perpendicular to the transverse axis of the chamber and the adjustment facility is such that the angle of the direction of vibration in that plane can be adjusted to give the desired effect. In one embodiment of the invention two vibrator motors are provided one at each side of the drying chamber.
Reference is now made to the accompanying drawings in which:
Figure 1 is a cross section of a drying apparatus according to the present invention;
Figure 2 is a plan view of the apparatus shown in Figure 1;
Figure 3 is a longitudinal section of the apparatus shown in Figure 1;
Figure 4 is a cross-section through an alternative form of apparatus according to the invention;
Figure 5 is an exploded perspective view showing the construction of the distribution means; and
Figure 6 is a side elevation of a drying plant.
Referring to Figure 1 the apparatus comprises a frame 10 which supports a drying chamber 11 mounted in said frame 10 by anti-vibration mountings. Air is arranged to enter a distribution chamber 13 from a drying air inlet 1 5 which communicates with a heating chamber 16. The air, the direction of flow of which is indicated by the arrows, if deflected by means of the use of angularly displaced deflector plates 14 and it can be seen that the arrangement of these plates is such as to avoid turbulence caused by the crossing of air streams.
The deflected air travels upwardly and is distributed by the distribution means 1 7 the construction of which is described in more detail hereinafter. This air is used to dry leaf material in the chamber 11 in a fluidised condition and the spent air is collected in the extractor hood 1 8.
The apparatus is provided with a pair of vibrator motors 1 9 which can vibrate the chamber 11 relative to the frame 10 by virtue of the mountings 12. The motors 19 are arranged to be rotatable about a pivot 20 to select the positions so that the plate of vibration can be adjusted to provide the desired- motion of the leaf material being dried and to urge it in the direction of the discharge area 22. It will be appreciated that the angle of the vibration is adjusted within a single plane, i.e. a plane parallel to the section shown in
Figure 3. The vibration of the chamber 11 also assists preventing the formation of "balls" of tea and enables an evenly dried product to be obtained.
In operation the dried leaf gradually progresses from the chamber 11 to the discharge area 22 where it is discharged over a weir 21 which may be adjustable in height.
The construction of the distribution means 1 7 will now be described in more detail. It comprises a rectangular grid formation 1 7a having on its upper surface a plate 1 7b provided with a plurality of apertures and with a fabric mesh 1 7c.
The grid 1 7a serves both to separate the plate 1 7b from the mesh 1 7c and also to confer rigidity of the construction.
The plate is preferably an apertured metal plate which serves to transmit and distribute the vibrations to the tea being dried whilst also permitting the passage of air at a rate suitable to maintain fluidisation. The fabric serves to distribute the air evenly in the chamber and to this end it has flow characteristics which are such that the resistance to flow of air through the mesh increases with the rate of flow. This property tends to avoid the production of "blow holes" in the fluidised bed since these generate a localised increase in flow rate and this is counteracted by the increasing resistance to flow.
The fabric mesh should be capable of withstanding the operating conditions of the apparatus and should have a high fatigue life, comprise an inert material and have adequate temperature resistance.
Figures 4 and 5 show an alternative embodiment of the invention.
The apparatus comprises a frame 40 which supports distribution means 41 by means of vibration mountings 42. Above the distribution means 41 there is a drying chamber 43 which is defined in part by the defining walls 44 and in part by the flexible seal curtain 45. The flexible seal curtain is fixed at its upper end to a structure 46 which is rigid with the frame 40 and is free at its lower end which is in contact with the walls 44.
The walls 44 are held rigidly by a plurality of angle members 48 and 49.
The distribution means 41 is mounted above an air supply duct 47 and the air which passes through the drying chamber 43 is taken off by a hood (not shown).
The distribution means is arranged to be vibrated relative to the frame by means of a pair of vibration motors 1 9 which can be adjusted relative to the distribution means in a manner similar to that described in relation to the embodiment shown in Figures 1 to 3.
Figure 5 shows an exploded perspective view of one distribution element 50. A plurality of such distribution elements 50 are arranged parallel with one another and resting on the upper angle member 49 so as to cover the entire lower surface of the drying chamber 43.
Each distribution element 50 comprises a
ladder-like base frame 51 which is rectangular in
plan and includes a plurality of transverse
reinforcing members. A layer of fabric mesh
having the required properties as defined above is then disposed over the rectangular base frame 51 so as to cover the entire surface thereof and the
assembly is completed by the cover 53 which is an interference fit over the fabric and base frame
51 so that the fabric is retained in position. The
cover 53 has an apertured upper surface and
constitutes the apertured metal plate. The spacing
and size of the aperture in the plate 53 should be
such that in combination with the fabric mesh 52
the desired characteristics of the distribution
means are obtained.
Referring to Figure 6 a drying plant is shown which plant comprises three drying apparatus as shown in Figures 4 and 5 arranged in series.
The leaf material to be dried is transported by a conveyor 60 and deposited in the drying chamber of a drying apparatus 61. The apparatus 61 is fed with drying air via an air supply duct 65 and the distribution means is vibrated by a vibration motor 1 9.
The partially dried leaf material flows over a weir 66 into the drying chamber of a second drying apparatus 62 which is provided with a vibration motor 1 9 and is fed with drying air from an air supply duct 64. In this apparatus the leaf material is dried further and then flows over a weir 67 into a third drying apparatus 63. The third drying apparatus 63 is also fed with air from supply duct 64 and is provided with a weir 68 over which dried leaf material can flow on to the discharge conveyor 69.
It will be appreciated that each of the weirs 66, 67 and 68 can be adjustable in order to achieve the desired flow of leaf material from the input conveyor 60 to the discharge conveyor 69.
It will.be apparent that a blowing fan (not shown) will be provided in each air supply duct 64 and 65 and if desired a heat exchange is also included in each duct.
In use the apparatus could be used to dry leaf material by feeding the leaf material to be dried on conveyor 60 and discharging dried material on discharge conveyor 69. It is preferred to use a gas flow providing a bed face velocity of 200 feet per minute and a pressure drop across the distribution means of about 2 to 3 inches water gauge.
The apparatus of the present invention has been found to provide very even drying of leaf material such as tea or tobacco. Consequently the apparatus is capable of producing a dry product of higher quality than is possible with conventional driers. In addition the drying apparatus functions more efficiently than conventional apparatus.
It will be appreciated that whilst in the foregoing description the apparatus has been described for drying leaf material such as tea or tobacco it could also be used for conditioning other materials, such as by drying or cooling, by providing a flow of gaseous medium at the appropriate temperature and humidity.
Claims (15)
1. A conditioning apparatus for conditioning leaf material comprising a conditioning chamber disposed above gas distribution means, means for supplying gaseous medium to said chamber through said gas distribution means, said gas distribution means having a resistance to flow of gaseous medium which increases as the rate of flow through the distribution means increases, whereby when the apparatus is in use the leaf material to be conditioned is maintained in a fluidised state.
2. An apparatus according to Claim 1 in which the distribution means comprises an apertured plate and a mesh.
3. An apparatus according to Claim 2 in which the mesh is a fine mesh fabric.
4. An apparatus according to any of Claims 1 to 3 in which the distribution means is such as to provide a pressure drop of 1 to 8 inches water gauge for a bed face velocity of 1 50 to 250 feet per minute.
5. An apparatus according to any of Claims 1 to 3 in which the distribution means is such as to provide a pressure drop of 1.5 to 4 inches water gauge for a bed face velocity of 1 50 to 250 feet per minute.
6. An apparatus according to any of Claims 1 to 3 in which the distribution means is such as to provide a pressure drop of 2 to 3 inches water gauge for a bed face velocity of 1 50 to 250 feet per minute.
7. An apparatus according to any of Claims 1 to 6 in which the bed face velocity is 200 to 220 feet per minute.
8. An apparatus according to any of Claims 1 to 6 in which the bed face velocity is about 200 feet per minute.
9. An apparatus according to any of Claims 1 to 8 which is provided with at least one vibration device.
1 An apparatus according to Claim 9 in which the the vibration device is arranged to provide a linear vibration and the device can be adjusted relative to the chamber.
11. An apparatus according to any of Claims 3 to 10 in which the distribution means comprises at least one frame having a layer of fine mesh fabric superimposed thereon and an apertured plate in the form of a cover which fits on the frame and retains the fabric in position.
12. An apparatus according to any of Claims 1 to 11 which is provided with a weir for the discharge of material.
13. An apparatus according to Claim 12 in which the weir is adjustable.
14. An apparatus according to any of Claims 1 to 13 in which the means for supplying gaseous medium to said chamber includes deflector plates to deflect the flow of medium towards the distribution means.
1 5. An apparatus for conditioning leaf material substantially as herein described with reference to and as shown in Figures 1 to 3 or Figures 4 and 5 of the accompanying drawings.
1 6. A conditioning plant comprising one or more conditioning apparatus as claimed in any of
Claims 1 to
1 5.
1 7. A conditioning plant substantially as herein described with reference to and as shown in the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7924736A GB2026668B (en) | 1978-07-27 | 1979-07-16 | Conditioning apparatus |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7831377 | 1978-07-27 | ||
| GB7924736A GB2026668B (en) | 1978-07-27 | 1979-07-16 | Conditioning apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2026668A true GB2026668A (en) | 1980-02-06 |
| GB2026668B GB2026668B (en) | 1982-10-13 |
Family
ID=26268364
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7924736A Expired GB2026668B (en) | 1978-07-27 | 1979-07-16 | Conditioning apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2026668B (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0136139A2 (en) * | 1983-09-16 | 1985-04-03 | Hambro Machinery Limited | Distribution means |
| WO1987003508A1 (en) * | 1985-12-04 | 1987-06-18 | Dieter Roddewig | Process and device for drying and/or burning powdery materials |
| US4755284A (en) * | 1984-04-14 | 1988-07-05 | Hambra Machinery Limited | Elutriator |
| WO1990003124A1 (en) * | 1988-09-26 | 1990-04-05 | Gbe International Plc | Method of conditioning tobacco and apparatus therefor |
| GB2239305A (en) * | 1989-12-23 | 1991-06-26 | Myron Grant Hampton | Drying tea |
| WO1998035569A1 (en) * | 1997-02-12 | 1998-08-20 | Comas S.P.A. | A drying machine for shredded tobacco, in particular for rolls of expanded shredded tobacco |
| CN103181611A (en) * | 2011-12-30 | 2013-07-03 | 贵州中烟工业有限责任公司 | Meshed plate structure for flash evaporation type drying machine fluidized bed |
| CN111023750A (en) * | 2019-11-19 | 2020-04-17 | 杭州利源化工有限公司 | Cotton dryer |
-
1979
- 1979-07-16 GB GB7924736A patent/GB2026668B/en not_active Expired
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0136139A2 (en) * | 1983-09-16 | 1985-04-03 | Hambro Machinery Limited | Distribution means |
| EP0136139A3 (en) * | 1983-09-16 | 1986-02-19 | Hambro Machinery Limited | Distribution means |
| US4755284A (en) * | 1984-04-14 | 1988-07-05 | Hambra Machinery Limited | Elutriator |
| WO1987003508A1 (en) * | 1985-12-04 | 1987-06-18 | Dieter Roddewig | Process and device for drying and/or burning powdery materials |
| WO1990003124A1 (en) * | 1988-09-26 | 1990-04-05 | Gbe International Plc | Method of conditioning tobacco and apparatus therefor |
| US5161548A (en) * | 1988-09-26 | 1992-11-10 | Gbe International Plc | Method of conditioning tobacco and apparatus therefore |
| GB2239305A (en) * | 1989-12-23 | 1991-06-26 | Myron Grant Hampton | Drying tea |
| WO1998035569A1 (en) * | 1997-02-12 | 1998-08-20 | Comas S.P.A. | A drying machine for shredded tobacco, in particular for rolls of expanded shredded tobacco |
| US6269550B1 (en) | 1997-02-12 | 2001-08-07 | Comas S.P.A. | Drying machine for shredded tobacco, in particular for rolls of expanded shredded tobacco |
| CN103181611A (en) * | 2011-12-30 | 2013-07-03 | 贵州中烟工业有限责任公司 | Meshed plate structure for flash evaporation type drying machine fluidized bed |
| CN111023750A (en) * | 2019-11-19 | 2020-04-17 | 杭州利源化工有限公司 | Cotton dryer |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2026668B (en) | 1982-10-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |