Tobacco Processing
During processing, bacteria will grow on tobacco and decay the leaves if the product is left untreated.
The Problem:
A chemical called KABAT prevents such bacterial degeneration and is a widely used solution to this problem. For this to be effective, it is essential that the correct quantity of KABAT is administered.
The Solution:
The chemical spray rate is based on the tobacco flow rate, and a variable dose rate set in parts per million (ppm). The system developed comprises of five Mantracourt integrated ADP15 indicator display's and an LCA15 weighing amplifier/digitiser module unit, a chute mounted load cell, and VisualLink software.
Tobacco flows over a chute which has a load cell mounted on a pivot. The load cell weighs the tobacco as it flows down the chute and transmits this to the LCA15. The LCA15 reads the tobacco flow rate from the load cell in kilograms per hour and transmits this as a 4-20mA signal to instruments A and D.
- Instrument D is a standard ADP15 which simply displays the flow rate of the tobacco and retransmits this signal to Display E
- Instrument A is an ADP15 with modified software. The software calculates a set-point for the KABAT pump controller based on the tobacco flow rate input from the LCA15 and transmits this as a 4-20mA signal to unit C. This unit also displays the tobacco flow rate in Kg/hr.
- Instrument B is an ADP15 with modified software that receives an input of the kg/hr tobacco flow rate, but displays the flow rate of the KABAT and then retransmits the tobacco flow.
- Instrument C is a dual input ADP15 display with modified software, which forms the main control of the system. This unit receives the set-point calculation from unit A and the tobacco flow rate from unit B. Using a PID algorithm control this unit then activates and controls the KABAT pump.
- Instrument E is a display only unit. It receives the tobacco and KABAT flow rates and displays the ppm level of the KABAT.
The PC link along with Mantracourt's VisualLink software enables the user to monitor all parameters in the system, providing clear display and information on dosing errors in the control room.
Products used in this application:
Process Controller, Indicator and Analogue Conditioner
Digital Panel Meter Process Indicator
