Quality Metrics and Points of Measurement
Taking care of green leaves and stems
For tobacco green leaf threshing (GLT) to work well, the leaf must have between 17 and 22% moisture. To get the right amount of moisture, green leaf tobacco is conditioned in cylinders with steam that can be changed to control how much moisture comes out. To optimize GLT and get the desired strand length, it’s important to measure the moisture level accurately.
By controlling the amount of steam, the moisture level of the stem is brought up to about 40%. This makes it more flexible for the cutting process of quality tobacco leaf processing.
To store tobacco safely for a long time and make sure it is of good quality, the lamina and stems must have a moisture level between 11 and 12%. When the lamina comes out of the drying chamber, it is somewhere between 6 and 8% moisture, and when it comes out of the humidity chamber, it is between 11 and 12% moisture. Usually, the packed leaves and stems are put away for at least 6 months to age or soften.
Temperature: In addition to measuring moisture, you can also measure temperature in real time to see how well drying and conditioning are going.
Measuring Points: Conditioning and Drying of Green Leaves and Stems
The Pioneer Tobacco (PT) MCT460-T Tobacco NIR Moisture Sensor can be placed at the entrance or exit of the conditioning cylinder and the drying chamber to measure moisture in real time. Closed loop process control makes it possible to get the most out of conditioning and drying by using the standard 4-20mA/0-10v output or an optional digital output (ProfiNet, ProfiBus, Ethernet IP, Modbus TCP, or DeviceNet).
The sensor is placed 8 to 10 inches above and far enough down the conveyor so that water vapor from the tobacco doesn’t affect measurements. A built-in IR temperature sensor can be added to the MCT460-T so that the temperature of the tobacco can be monitored during both drying and conditioning.
Moisture control is a very important part of the process of turning a green tobacco leaf into a finished lamina and stem. With a Pioneer Tobacco MCT460-T moisture analyzer for closed loop process control, all parts of the process will work as well as possible. It will help make a consistent, high-quality finished product that can be stored safely for months until it is used at a second processing plant to make a finished product.
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