Maintaining plasticizer temperature in tobacco filter rod formation, and apparatus therefor

Claim 2

In a cigarette filter rod forming operation in which a plasticizer material is conveyed from a pond thereof and applied to a tow band of filter material in an application operation preliminary to enclosing said tow band in a wrapper, the conveyance and application of said plasticizer being made under such conditions that heat is transferred to said plasticizer with a portion of the said plasticizer conveyed to the application operation being returned to said pond whereby the temperature of said pond tends to increase, the improvement of establishing and maintaining the temperature of said pond of plasticizer material at substantially the ambient temperature of the environment in which said forming operation is carried out by circulating a flow of cooling water through said pond in a closed circuit flow course extending substantially across the full expanse of said pond adjacent the bottom thereof.

Claim 3

The forming operation of claim 1 in which the plasticizer material is triacetin, and said pond is maintained at a temperature of about 70° F. to about 80° F.

Claim 4

In apparatus for forming cigarette filter rod which includes means for advancing a tow band of filter material in a predetermined direction, an upright tank, a source of plasticizer material received in said tank as a pond thereof, application means for applying said plasticizer material to said advancing tow band, and means for conveying plasticizer from said pond to said application means, there further being means for collecting and returning unused plasticizer from said application means to said pond, the improvement comprising means for maintaining the temperature of said pond at a value in a predetermined range, said means comprising a source of circulating cooling fluid, a coil disposed in said tank, said coil having at least a portion thereof disposed in said pond closely adjacent to but spaced from the bottom of said tank, said portion comprising a plurality of relatively sinuous windings disposed in substantialy planar alignment across substantially the full expanse of said tank, and means operative for establishing flow communication between said coil and said cooling fluid source whenever the temperature of the plasticizer in said pond exceeds the maximum value in said predetermined range, said means being inoperative whenever the temperature of the plasticizer in said pond is at a value within or below said predetermined range, said means for establishing flow communication between said coil and said cooling fluid source including a three-way valve having connection respectively with said cooling fluid source, said coil, and a by-pass conduit, and a thermostat control sensing the temperature of said plasticizer and operative to orient said three-way valve to pass cooling fluid from said source to said coil, or from said source to the by-pass conduit.

Claim 5

In apparatus for forming cigarette filter rod which includes means for advancing a tow band of filter material in a predetermined direction, an upright tank, a source of plasticizer material received in said tank as a pond thereof, application means for applying said plasticizer material to said advancing tow band, and means for conveying plasticizer from said pond to said application means, there further being means for collecting and returning unused plasticizer from said application means to said pond, the improvement comprising means for maintaining the temperature of said pond at a value in a predetermined range, said means comprising a source of circulating cooling fluid, a coil disposed in said tank, said coil having at least a portion thereof disposed in said pond closely adjacent to but spaced from the bottom of said tank, said portion comprising a plurality of relatively sinuous windings disposed in substantialy planar alignment across substantially the full expanse of said tank, and means operative for establishing flow communication between said coil and said cooling fluid source whenever the temperature of the plasticizer in said pond exceeds the maximum value in said predetermined range, said means being inoperative whenever the temperature of the plasticizer in said pond is at a value within or below said predetermined range, said means for establishing flow communication between said coil and said cooling fluid source including a three-way valve having connection respectively with said cooling fluid source, said coil, and a by-pass conduit, and a thermostat control sensing the temperature of said plasticizer and operative to orient said three-way valve to pass cooling fluid from said source to said coil, or from said source to the by-pass conduit.

Claim 6

The apparatus of claim 3 in which said cooling fluid is chilled water, the plasticizer material being triacetin, and the means for establishing flow communication between said coil and said pond of cooling fluid being operative whenever the temperature of the plasticizer exceeds 80° F.