Tobacco curing and drying apparatus
AssigneeTifcon Company
InventorJohn S. Taylor
Life of this patent
Estimating the term…
Abstract
Leaf tobacco or the like in a substantially airtight enclosure is cured and dried by circulating through the enclosure air that is controllably heated by a forced air fuel burner located in an elongated vertically oriented duct outside the enclosure. The outlet end of the duct is communicated with the enclosure at the bottom thereof, and its upper inlet end is controllably communicable with the enclosure at the top thereof and with the ambient atmosphere. The air intake port of the fuel burner receives only air flowing through the duct. Air circulation is effected by an electric motor driven fan near the inlet of the duct, and a restriction in the duct produces a pressure drop across the burner that prevents back-drafts through it.
Claims15
A method of processing products such as tobacco, wherein the products to be processed are placed in an enclosure which has an inlet and an outlet and through which heated air is circulated from said inlet to said outlet, which method comprises:
- A. communicating the outlet of the enclosure with the inlet of a duct that has its outlet communicated with the inlet of the enclosure;
- B. effecting a positive circulation of air through the enclosure by drawing air from its outlet and forcing it into the duct to thereby create a zone of positive pressure in the duct near its inlet to force the air through the duct towards its outlet;
- C. combusting fuel in the duct at a combustion zone located downstream of said zone of positive pressure;
- D. supplying air for such combustion from a location in the duct between said zone of positive pressure and said combustion zone;
- and
- E. creating a pressure differential through the combustion zone in the direction to establish a lower pressure downstream of the combustion zone than that which obtains at the location in the duct from which the air for combustion is taken, whereby heat and gases resulting from the combustion are constrained to flow through the combustion zone in the direction of air flow through the duct, to thereby minimize the possibility of any substantial back draft through the combustion zone.
Apparatus for processing products such as tobacco, by circulating heated air through an enclosure having an air inlet and an air outlet and in which the product being processed is so placed that the air being circulated through the enclosure from its inlet to its outlet can reach substantially all parts of the product, said apparatus comprising:
- A. means defining a duct having an outlet connected with the air inlet of the enclosure;
- B. air inlet means for said duct;
- C. means for communicating said air inlet means with the air outlet of the enclosure, so that air leaving the enclosure can enter the duct;
- D. air moving means having a suction side and a pressure side, located near said inlet means for effecting movement of air through the duct towards its outlet, and for concomitantly effecting circulation of air through the enclosure from its air inlet to its air outlet;
- E. a forced draft fuel burner having a fan with a definitely defined air intake, to force air entering said intake through the burner, the burner also having a mouth from which flame and hot gases issue when the burner is in operation;
- F. means mounting the fuel burner with its air intake communicating with the interior of the duct at a first zone thereof that is downstream of the pressure side of the air moving means and with its mouth debouching into the duct at a second zone thereof that is downstream of said first zone;
- and
- G. means forming a constriction in the duct between said first and second zones to cause air passing through the duct to have a substantially higher pressure at said first zone than at said second zone, and operable to constrain heat and hot gases issuing from the mouth of the fuel burner to flow therefrom only in the direction towards the outlet of the duct, and thereby eliminate the possibility of any substantial back draft through the burner whether it is in operation or not.
Apparatus of the type adapted for association with an enclosure in which products such as tobacco can be so arranged that heated air of regulated relative humidity circulated through the enclosure can contact substantially all portions of the product, and which apparatus has
- 1. a fuel burner for heating the air to be circulated through the enclosure, which fuel burner has a definitely defined air intake and a discharge mouth from which flame and hot gases issue when the burner is in operation, and
- 2. blower means having a suction side and a pressure side for effecting circulation of heated air and hot combustion gases issuing from the fuel burner, through the enclosure, said apparatus being characterized by:
- A. a duct having inlet means and outlet means both communicable with the interior of the enclosure so that air drawn into the duct from the enclosure by the blower means flows towards the outlet means of the duct;
- B. the fuel burner being of the forced draft type and having a fan to force air for combustion through the burner, and having its said air intake communicating with the duct interior at a defined location and its discharge mouth debouching into the duct downstream from said defined location;
- C. the blower means being located in the duct between its inlet means and said defined location, with its suction side facing the inlet means and its pressure side upstream of said defined location and facing the outlet means of the duct;
- and
- D. means defining a restriction in the duct between said defined location and the point at which the discharge mouth of the burner debouches into the duct to thereby effect a pressure differential in the duct by which the air flowing through the duct is at a lower pressure at said point than it is at said defined location in the duct, so that heat and gases issuing from the mouth of the burner are constrained to flow through the duct in the direction towards its outlet means, and the possibility of any substantial back draft through the burner is prevented whether the burner is in operation or not.
Dependencies are inferred from the claim text.