Abstract This invention relates broadly to an improved process for expanding tobacco and involves certain modifications of the basic process for expanding tobacco comprising the steps of (1) contacting the tobacco with liquid carbon dioxide to impregnate the tobacco with the liquid carbon dioxide, (2) subjecting the liquid carbon dioxide-impregnated tobacco to conditions such that the liquid carbon dioxide is converted to solid carbon dioxide and (3) thereafter subjecting the solid carbon dioxide-containing tobacco to conditions whereby the solid carbon dioxide is vaporized to cause expansion of the tobacco. The present invention pertains, in one embodiment, to an improvement in the basic process which involves controlling the moisture content of the tobacco which is employed in the first step of the basic process. A second embodiment of the present invention involves draining off excess liquid carbon dioxide, under controlled conditions, after the first step of the basic process and prior to the second step of the basic process. The present invention pertains, in a third embodiment, to an improvement which involves controlling the output moisture of the product which is recovered from the third step of the basic process. The present invention further relates to various combinations of the three embodiments set forth above and to an overall process which employs all three embodiments in a manner which permits exceptionally advantageous results.
In the method of expanding tobacco which comprises the steps of (1) impregnating the tobacco with liquid carbon dioxide under conditions such that substantially all of the liquid carbon dioxide is maintained in liquid form so impregnate the tobacco with the liquid carbon dioxide, (2) subjecting the liquid carbon dioxide-impregnated tobacco to conditions such that the liquid carbon dioxide is converted to solid carbon dioxide and (3) thereafter subjecting the solid carbon dioxide-containing tobacco to conditions whereby the solid carbon dioxide is vaporized to cause expansion of the tobacco, the improvement which comprises: (i) utilizing as the tobacco which is employed in step (1) a tobacco which has an OV content of from about 17 to about 30%, (ii) conducting the impregnation step under pressure in the range of from about 250 psia to about 450 psia, and (iii) conducting the third step in such a manner that the moisture content of the expanded tobacco obtained from the third step is no higher than about 6%.
Claim 2
Dependent Claim
166 words
In the method of expanding tobacco which comprises the steps of (1) impregnating the tobacco with liquid carbon dioxide under conditions such that substantially all of the liquid carbon dioxide is maintained in liquid form so impregnate the tobacco with the liquid carbon dioxide, (2) subjecting the liquid carbon dioxide-impregnated tobacco to conditions such that the liquid carbon dioxide is converted to solid carbon dioxide and (3) thereafter subjecting the solid carbon dioxide-containing tobacco to conditions whereby the solid carbon dioxide is vaporized to cause expansion of the tobacco, the improvement which comprises: (i) utilizing as the tobacco which is employed in step (1) a tobacco which has an OV content of from about 17 to about 30%, (ii) conducting the impregnation step under pressure in the range of from about 250 psia to about 450 psia, and (iii) conducting the third step in such a manner that the moisture content of the expanded tobacco obtained from the third step is no higher than about 6%.
Claim 3
Dependent Claim
47 words
The method of expanding tobacco of claim 1, wherein the impregnation step is conducted at a pressure of from about 350 psia to about 450 psia and the tobacco which is employed in step (1) has an initial OV content of from about 17 to about 25%.
Claim 4
Dependent Claim
37 words
The method of expanding tobacco of claim 1 wherein the third step is conducted in such a manner that the moisture content of the expanded tobacco obtained from the third step is no higher than about 3%.