Method and apparatus for conditioning tobacco

A method of conditioning tobacco, comprising the steps of transporting a continuous stream of tobacco particles at a constant rate along a predetermined path;

• measuring the initial moisture content of successive increments of the stream in a first portion of said path;
• increasing the moisture content of the particles in a second portion of said path when the measured initial moisture content is below a predetermined value, including conveying streamlets of steam transversely across the stream in said second portion of said path and simultaneously contacting the particles of tobacco in said second portion with droplets of a liquid medium;
• drying the particles of said stream in a third portion of said path, including conveying a first current of a hot gaseous fluid through said third portion of said path concurrent with the direction of transport of tobacco particles and conveying a second current of a hot gaseous fluid counter to said direction in the region where successive increments of the stream leave said third portion;
• establishing a further current of hot gaseous fluid;
• dividing said further current into said second current and a fourth current;
• measuring the final moisture content of dried tobacco particles in a fourth portion of said path;
• and varying the ratio of fluids in said second and fourth currents when the measured final moisture content deviates from a predetermined vlaue.

A method of conditioning tobacco, comprising the steps of transporting a continuous stream of tobacco particles at a constant rate along a predetermined path;

• measuring the initial moisture content of successive increments of the stream in a first portion of said path;
• increasing the moisture content of the particles in a second portion of said path when the measured initial moisture content is below a predetermined value, including conveying streamlets of steam transversely across the stream in said second portion of said path and simultaneously contacting the particles of tobacco in said second portion with droplets of a liquid medium;
• drying the particles of said stream in a third portion of said path, including conveying a first current of a hot gaseous fluid through said third portion of said path concurrent with the direction of transport of tobacco particles and conveying a second current of a hot gaseous fluid counter to said direction in the region where successive increments of the stream leave said third portion;
• measuring the final moisture content of dried tobacco particles in a fourth portion of said path;
• and varying the quantity of fluid in said second current when the measured final moisture content deviates from a predetermined value, said drying step further comprising the steps of subjecting the particles in said third portion of said path to the heating action of a second fluid and varying the quantity of said second fluid as a function of variations of the quantity of fluid forming said second current.

Apparatus for conditioning tobacco, comprising means for transporting a stream of tobacco particles at a constant rate along a predetermined path;

• monitoring means for measuring the initial moisture content of successive increments of the stream in a first portion of said path;
• means for moisturizing successive increments of the stream in a second portion of said path when the measured initial moisture content is below a predetermined value;
• means for drying successive increments of the stream in a third portion of said path, said transporting means including a rotary drum-shaped conveyor defining said third portion of said path, said conveyor having an inlet and an outlet and said drying means including means for admitting a hot gaseous fluid into said inlet and means for admitting a hot gaseous fluid into said outlet;
• means for withdrawing spent fluid at the outlet of said conveyor;
• a source of hot gaseous fluid;
• means for connecting said source with both said fluid admitting means;
• means for maintaining the temperature of fluid which issues from said source at a substantially constant value;
• means for measuring the final moisture content of dried tobacco particles in a fourth portion of said path;
• means for varying the rate of flow in one of said fluid admitting means when the measured final moisture content deviates from a preselected value;
• and third fluid admitting means branching off said one fluid admitting means, said means for varying the rate of flow in said one fluid admitting means including means for increasing the rate of fluid flow via said one admitting means while simultaneously reducing the rate of fluid flow via said third admitting means and vice versa.

Apparatus for conditioning tobacco comprising means for transporting a stream of tobacco particles at a constant rate and in a predetermined direction along a predetermined path;

• monitoring means for measuring the initial moisture content of successive increments of the stream in a first portion of said path;
• means for moisturizing successive increments of the stream in a second portion of said path downstream of said first portion, as considered in said direction, when the measured initial moisture content is below a predetermined value;
• means for drying successive increments of the stream in a third portion of said path downstream of said second portion, including adjustable heating means for tobacco particles in said third portion of said path;
• second monitoring means for measuring the final moisture content of successive increments of the stream in a fourth portion of said path;
• and means for adjusting said heating means when the measured final moisture content deviates from a preselected value.

Apparatus for conditioning tobacco comprising means for transporting a stream of tobacco particles at a constant rate and in a predetermined direction along a predetermined path;

• monitoring means for measuring the initial moisture content of successive increments of the stream in a first portion of said path;
• means for moisturizing successive increments of the stream in a second portion of said path downstream of said first portion, as considered in said direction, when the measured initial moisture content is below a predetermined value, said transporting means comprising a substantially tunnel-shaped conveyor which defines said second portion of said path and includes an apertured wall along which successive increments of the stream are transported in said second portion, said moisturizing means comprising a source of liquid, at least one spray nozzle in said conveyor, and means for connecting said source of liquid with said nozzle;
• a source of steam;
• means for connecting said source of steam with said apertured wall so that jets of steam issue from the apertures of said wall and traverse the tobacco stream in said conveyor;
• and means for drying successive increments of the stream in a third portion of said path downstream of said second portion.