US2184275A - Redrying of tobacco - Google Patents

Description

Patented Dec. 26,1939 v uNirEo sures ATE-l oFFice REDRYING OF TOBACCO John M. Baer, Chicago, 111., assignor to The Guardite Corporation, a corporation of Illinois No Drawing. Application February 26, 1938, Serial No. 192,881

6 Claims. (CI. 34-24) This invention relates to redrying of tobacco reduced, say, to 50, at which temperature the and more particularly, to redrying of tobacco in tobacco may be discharged. hogsheads. Owing to the fact that superheated steam is When tobacco is brought into the market used on all steaming operations, whereas satufrom the farm, it is customary for thefarmer to rated steam only is withdrawn by the evacu- 5 wait for a moist day so that the tobacco will be ating process, each step of the process results in reasonably pliable and capable of being handled a reduction of the moisture content, so that the without breaking. This extra moisture, however, final moisture content of the tobacco is substantogether with the natural moisture of the tobactially be ow t as Originally At the Same 10 co, frequently renders it unfit for storage and it time, the tobacco receives the necessary heat 10 is therefore customary to redry th tob cco, treatment for proper stabilization of the material This redrying has heretofore been carried out o S age upon individual leaves of tobacco and not in the Preferably, the operation is carried out in a hogshead, it being customary to heat the tobacco heated C p a Vacuum ehemin a current of warm air. This operation is exber may be heated by a series of steam coils on 15 tremely expensive and involves an excessive the inside of its walls. The use of the internal amount of handling. heat to some extent makes up for the cooling In accordance with this invention, the tobacco y evap rat n ut is a s f importance in p is redried while in the original hogshead and in ventin Condensation 0n the Wells Which ou a very short period. have the effect of partially de-superheating the 20 The redrying operation is only in part a mat- Steam e p y in the heating y s.

ter of removal of moisture. It also affects the The foregoing detailed description has b botanical and chemical characteristics of the v n f cloarness f understanding y, a d tobacco. no unnecessary limitations should be understood In accordance with this invention, green totherefrom. 25 bacon in a hogshead is placed in a vacuum cham- I claim: her and subjected to a vacuum sufliciently high 1. The method of redrying tobacco which comto boil water therefrom at the temperature of prises substantially freeing the tobacco from the tobacco until it is substantially free of nonnon-con-densible gases, heating the tobacco with so condensible gas. The product may, however, superheated steam to an elevated temperature of be substantially freed of non-condensible gases at least 140 F. and then cooling the product by in any other suitable manner. evaporation of contained moisture in a vacuum Thereafter highly superheated steam isintroto produce a product of lower moisture content duced to bring the temperature of the tobacco than the original tobacco.

175 to 200 F.' The tobacco is then cooled by head which comprises substantially freeing the subjection to a vacuum and the process repeated. hege ead from ne -eo s e heating the Preferably, the cooling operation will not lower tobacco with highly superheated steam to a temthe temperature more than 50 to 75 and the perature of over 175 F., cooling the tobacco by 40 subsequent steaming with superheated steam evaporation of Contained moisture, again heating 40 will be to a lower temperature than the initial the product with superheatedsteami to somewhat lower temperature than the initial For example, the tobacco at 60 F. may be'subheating temperature? again cooling jected to a vacuum until its tem erature has by i of molsture cooling bemg dropped m 0 F followed by Steaming with carried out until the tobacco is at a lower tem- 45 highly superheated steam to F. The mom perature than after the first coollng operation, um is then increased until the temperature has and repe-atmg the cycl-e the tobacco has a n o substantially lower moisture content and a final dropped to, say, F. followed by a second tem erature sub"tantiall of the order of the 50 steaming operation'with superheated steam to p b y 9 initial temperature of the tobacco. 50 175 h temperature may then be reduced 3. The method as set forth in claim 1 in which to S y, y evacuation, felleWed by the operation is carried out in an enclosed zone, t0 With superheated Steam and Subseto the periphery of which heat is applied indeo n evacuation y, In he next sta pendently of the introduced steam during the 55 the temperature may be carried to F. and. operation. 55

so to a much highe temperature, preferably from T e met od of red y g tobacco in a hOgS- with superheated steam to raise the temperature substantially less than the amount the tobacco was previously cooled, and continuing the cooling and heating in this manner until the tobacco has a temperature approximately atmospheric and a moisture content substantially below the original moisture content.

6. The method as set forth in claim 5, in which the tobacco is continuously heated during the process.

JOHN M. BAER.