Tobacco leaf curing system

• US 3,937,227 A
• Filed: 02/28/1974
• Issued: 02/10/1976
• Est. Priority Date: 02/28/1974
• Status: Expired due to Term

• Current Assignee: Sansyu Sangyo Company Limited
• Original Assignee: Sansyu Sangyo Company Limited
• Inventors: Azumano, Hideyuki
• Primary Examiner(s): Reich, Joseph S.
• Application Number:
  US05/446,766
• Time in Patent Office: 712 Days
• Field of Search: 131/134, 131/135, 131/140, 34/225, 34/46
• US Class Current: 131/302
• CPC Class Codes: A24B 1/02 Arrangements in barns for preparatory treatment of the tobacco, e.g. with devices for drying

Abstract

A tobacco leaf curing system comprising an air tight curing house divided by a porous floor plate into an upper curing barn and a lower blast chamber, the curing barn being provided at its upper portion with a circulation port and an outlet port; a circulation duct passageway containing duct fan means and heating means, said circulation duct passageway communicating with the circulation port for drawing air from the curing barn, said air being compressed by said duct fan means and heated by said heating means and then reintroduced into the blast chamber through a blast port; an automatic temperature regulator associated with the burner of the heating means for automatically igniting or extinguishing said burner according to variations appearing on a wet-bulb temperature sensor so as to regulate the temperature and humidity of the air to be sent to the blast chamber; an inlet control system comprising a cylindrical damper provided with openings and located in said circulation duct system, said inlet control system being so arranged that, with the rotation of said damper, the inlet port is automatically opened in a progressive manner as the leaf setting stage begins and is closed again before the stem drying stage is completed, said inlet control system also varying the mixing ratio of the external air to the recycled, heated air being supplied to the blast chamber for each curing stage; and an outlet port control mechanism which is located at the outlet port opening on a side of said curing barn, said outlet port control mechanism automatically opening or closing according to the amount of air which is drawn through the inlet port of the inlet port control system so that the air which has passed through the curing barn may be partially exhausted through the outlet port to the exterior of said barn.

Claims

1. A tobacco leaf curing plant for processing tobacco leaves which comprises a substantially air-tight curing barn divided by a porous floor plate into an upper drying chamber adapted to house the tobacco leaves and a lower air chamber, a circulation duct passageway containing fan means and the heating means, an air circulation port means providing communication between one end of the circulation duct passageway and the drying chamber for drawing air from the drying chamber, and a distribution chamber disposed at the other end of the circulation duct passageway, said distribution chamber providing communicatin between said other end of the circulation duct passageway and the lower air chamber for introducing air compressed by said fan means and heated by said heating means into said lower air chamber, an ambient air inlet port provided with an automatic for controlling the amount of ambient air drawn from the atmosphere through the inlet port and introduced into the air circulation duct passageway so as to change the mixing ratio of the ambient air to the circulating air being supplied to the lower air chamber, an automatic temperature regulator connected to the fan means and the heating means and a wet bulb temperature sensor connected to the automatic temperature regulator, said temperature regulator adjusting the heating means according to variations appearing on the wet bulb temperature sensor, thereby regulating and maintaining the temperature and humidity of the air sent to the lower air chamber at a fixed, predetermined level, and an outlet port means disposed in the wall of the drying chamber for exhausting a portion of the air from the drying chamber to the atmosphere, said outlet port means being provided with a control plate associated therewith, and means for opening or closing the outlet port means depending upon the presure differential between the circulating air inside the drying chamber and the atmospheric air.

2. The tobacco leaf curing plant of claim 1, wherein a plurality of porous baffle plates extend substantially perpendicularly from the porous floor plate into the lower air chamber.

3. The tobacco leaf curing plant of claim 2, wherein the length with which the baffle plates extend from the porous floor plate progressively increases as said baffle plates are further removed from the distribution chamber.

4. The tobacco leaf curing plant of claim 1, wherein the ambient air inlet port containing the automatic control system is disposed between the air circulation port means and the fan means.

5. The tobacco leaf curing plant of claim 1, wherein the air circulation duct passageway is divided by partition means into an upper fan chamber and a lower heating chamber, said upper fan chamber containing the fan means and said lower heating chamber containing the heating means, said upper fan chamber communicating with the drying chamber through said air circulation port means and said upper fan chamber communicating with said lower heating chamber through said fan means mounted in the partition means.

6. The tobacco leaf curing plant of claim 5, wherein the distribution chamber provides communication between the heating chamber and the lower air chamber, said distribution chamber being provided with a plurality of guide plates arranged substantially parallel to each other for directing the heated air uniformally through the air chamber.

7. The tobacco leaf curing plant of claim 1, wherein the ambient air inlet port is provided in the fan chamber and said automatic control system is installed in the inlet port and comprises a hollow cylindrical drum containing opposing air passage openings in its circumferential wall thereby providing communication between the fan chamber and the atmosphere through said inlet port and a damper means slidably disposed within said cylindrical drum, said damper means being provided with motor means for rotating said damper means to open and close the opposing air passage openings and thus the ambient air inlet port.

8. The tobacco leaf curing plant of claim 7, wherein the damper is electrically connected to automatic control means which generates an electrical signal at predetermined intervals for controlling the angular postion of said damper.

9. The tobacco leaf curing plant of claim 1, wherein the wet bulb temperature sensor is located at the forced, heated air inlet side of the drying chamber.

10. The tobacco leaf curing plant of claim 9, wherein the wet bulb temperature sensor includes an evaporation water tank, a reservoir adapted to supply said water tank with water, and including means whereby said tank is filled to a predetermined level, said temperature sensor being enveloped by a piece of cloth which is partially disposed in the water.

11. The tobacco leaf curing plant of claim 1, wherein storage casings are disposed on opposite sides of the porous floor plate and the tobacco leaves are packed in said storage casings.

12. The tobacco leaf curing plant of claim 1, wherein the drying chamber contains side walls and support members are fixed to said side walls said support members being provided with leaf hanging bars which hold the tobacco leaves by their bases.

13. The tobacco leaf curing plant of claim 1, wherein the storage casings have a U-shaped cross-section provided with front and rear portions, said casings containing locking hooks with auxiliary plates detachably fixed thereto, said casings being adapted to be packed in the field with tobacco leaves for curing in the leaf curing plant.

14. The tobacco leaf curing plant according to claim 13, wherein each of the side plates of the U-shaped casing is fitted in the inner surface of the rear portion thereof with suspender clips which open under spring pressure, thereby holding the stem base portions of the tobacco leaves in a suspended state.

15. The tobacco leaf curing plant of claim 12, wherein the hanging bars comprise a core including a sponge bar, support plates carried by said bar on opposite sides thereof, holders removably provided in opposition to the respective ones of said plates, said suspenders fixed to the outer sides of the plates and to the inner sides of the holders, respectively, the stem bases of said leaves being held between the bar and suspenders so that the leaf hanging bars clamping the leaves can be hung on hooks secured to both sides of the leaf curing plant.

16. The tobacco leaf curing plant of claim 1, wherein the heating means is a heat exchange device provided with a burner, said temperature regulator being connected to said burner.