US2207755A - Recycling system for moistening tobacco - Google Patents

Description

y 16, 1940- P. H. PALMER 2,207,755

RECYCLING SYSTEM FOR MOISI'ENING TOBACCO Filed Sept. 50, 1939 Z7 zd@2'z5302-: faaaZ/Y faZizzer. 5M z M4, @m; My $4 Patented July 1 6, 1940 UNITED STATES PATENT OFFICE Paul 11. Palmer, Jacksonville, Fla., assignor to The Guardite Corporation, a corporation of Illinois Application September 30,1939, Serial No. 297,352

5 Claims.

This invention relates to a recycling system for moistening tobacco.

In the treatment of tobacco, in which the material is subjected in hogsheads or bales to a 5 highyacuum and is then steamed, after which the evacuation cycle is repeated to remove a considerable amount of water from the tobacco, it is customary to employ multiple-stage steam ejector systems for the evacuation, particularly for the later stages of vacuum where large amounts of water vapor must be handled. The steam ejectors are quite efl'icient and the amount of steam required for their operation is relatively small compared with the amount which is uti- 1 lized in the steaming operation.

The products from the steam ejector are customarily condensed in a barometric condenser or semi-barometric condenser. In handling tobacco, however, these products are contaminated Q with extraneous materials from the tobacco, the nature oiwhich is not fully understood, and which make the utilization of the water in a steam boiler undesirable.

The present invention affords a process by 85 which the condensate from the steam ejection sys m may be re-employed i'or steaming the tobaccp-without passing through the coils of the boiler and in' which, by such utilization, the amount of material evaporated from the tobacco '0 is kept at a minimum due to the return of the evaporated materials in the subsequent cycles.

The invention is illustrated diagrammatically in the drawing in which ||l represents a conventional vacuum chamber provided with a vacuum line H and a steaming line l2, A system of steam ejectors l3. which is supplied with steam through the line H from the boiler l5, may be utilized to draw the necessary vacuum in the chamber, I have not shown the customary mechanical pump move the bulk of the air when the operating cycle commences. The discharge from the steam jets enters a barometric leg l6 through the line l1, and the condensate is collected in the receiver I8, 45 which constitutes a part of the barometric leg. From this point the condensate is pumped through the line I! and through the heat exchanger in which the condensate or a portion thereof is evaporated by heat exchange with high 0 pressure steam which passes into the heat exchanger through the line 2|. A suitable trap (not shown) is provided in the upper portion oi the heat exchanger through which a portion 0! the condensate may be drawn oil through the 55 valve 23 into the receiver 24. The volatilized which is usually included in the system to re condensate passes out of the heat exchanger through the line 25 and through the T 26 into the line l2.

Any condensed high pressure steam, together with uncondensed. steam, if there is any, passes through the line 22 and the pump 21 to the boiler IS. A second pump 28 is provided in line l9 to pass'the condensate through the heat exchanger. As a typical example of the operation of the system, the tank I0 is evacuated to a suitably high vacuum, say an absolute pressure of 0.3 inch, initially by a mechanical vacuum pump which is not shown, and in the final stages by the admission of steam through the line M in the steam ejector system l3. This requires relatively little steam which, however, is condensed in the baro: metric leg It. In the initial operations, where there may not be suiiicientv condensate, a high pressure steam may then be admitted through the line l2 from the boiler I5 to the tank by opening valves 30 and 3|, valves 32 and 33 in lines 25 and 2| respectively being closed. At the same time valves 34 and 35 in lines II and M will likewise be closed, and pumps 21 and 28 will not be operating.

After the tobacco in the tank In has been raised to the proper temperature by the steam, valves 30 and 3| are closed, and valves 34 and 35 opened in order again to evacuate the chamber. During this procedure large amounts of water vapor contaminated with volatiles of the tobacco pass into the steam ejection system and. are condensed in the barometric leg.

After the vacuum has been increased to the desired degree, valves 34 and 35 'may again be closed, valve 36 in line I3 is opened, and pumps 21 and 28 are started. At this time valve 33 in line 2| and valve 34 in line 22 are opened. as are valves 32 and 30. The condensate from the receiver I3 is thus pumped through the heat exchange wherein all or a portion of it is volatilized and passes into the chamber ID as low pressure steam. Preferably the steam will not have a pressure much over 8 lbs., 3 to 8 lbs, being the preferred range when employing high pressure steam which is customarily from 40 to 100 lbs. The high pressure steam passing through the heat exchanger is preferably condensed and the liquid is passed back to the boiler by the pump 21. It will be seen that in this manner steam is provided for the moistening of tobacco without beingcontaminated by the volatiles thereof.

In practice, the amount of steam added to the system through the line l4 for evacuation purposes is. in the same neighborhood as the net amount required in moistening'the tobacco, al-

though it is of course much less than the gross amount required for that purpose where several moistening steps are included in the treatment of a single batch of tobacco. However, if the condensate proves insuflicient, make-up steam may be added from the boiler as required. On'the other hand, if the condensate tends to build up material which is unvaporizable, or which reaches a concentration sufiiciently high to raise the viscosity of the condensate undesirably, a stream may be bled from the condensate just sufiicient to maintain the desired operating conditions. Suitably this may be done through the trap and draw-off line 23 in connection with the heat exchanger, the trap receiving the liquid when most concentrated. In this way it is sometimes possible to procure a draw-off liquid of commercial value.

What I claim as new, and desire to secure by Letters Patent, is:

1. In the treatment of tobacco, during which a high vacuum is drawn on the tobacco, the tobacco is steamed to raise its temperature and moisture content and is later subjected to an increased vacuum to reduce its moisture content, the steps of condensing water evaporated from the tobacco, re-evaporating it by heat exchange contact with steam, and utilizing the re-vaporized condensate for further moistening of tobacco.

2. The method as set forth in claim 1, in which the evacuation of water from the tobacco is induced by steam, and the steam used for this purpose is condensed with the water vapor from the tobacco.

3. The method as set forth in claim 1, in which the steam utilized to volatilize the condensate is recycled to a combustion source of thermal energy without admixture with any of the condensate.

4. Apparatus for the treatment of tobacco comprising an enclosed chamber, steam ejector means for evacuating the chamber, a boiler connected with the ejector and adapted to supply high pressure steam thereto, means connected with the discharge side of the steam ejector system for condensing the vapors therefrom, means for passing condensate in heat exchange relationship with steam from said boiler whereby the condensate is volatilized without contaminating the steam from the boiler, and means for admitting the revolatilized condensate to the vacuum chamber.

5. Apparatus as set forth in claim 4, in which means are provided for withdrawing a bleeder stream from the condensate.

PAUL H. PALMER.

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