Scope of work
Automation works was asked for a fully automated Dryer and Cleaner for Sentraal Suid Kooperasie.
Instrumentation
Temperature probes, motorised valves and fans are used for the process of drying. Siemens CPU 315-2 PN/DP was the main PLC and we used a Siemens ET200 cards to control the Dryer from the PC that is running a Wonderware InTouch Scada System in the control room.
Design
The process of Drying and Cleaning starts at the product being transferred from the silo to the cleaner. The product then went through the cleaning process and when necessary being transferred from the cleaner to the dryer where the drying process will take place. When done with Cleaning and Drying, the product is being transferred to the selected silo. Temperature probes are used to monitor the heat within the dryer.
Installation
After all the mechanical installation were done and the panels was on site, the wiring and cable rack was done in 2 weeks. Which includes all the motors, temperature probes and motorised valves.
Commissioning
The commissioning was done right after the installation. The commissioning took one week to test and make sure everything works correctly.
Dryer Description
Drying starts at the bottom of the bin, which is the first place air contacts. The dry air is brought up by the fan through a layer of wet grain. The grain below drying zone is in equilibrium moisture content with drying air, which means it is safe for storage; while the grain above still needs drying.
Cleaner Description
Cleaning begins with screening to remove coarse and fine materials and the grain is separated by size, shape and weight. The finished product, whole pure wheat, is then passed into conditioning bins. Conditioning takes place before milling to produce a uniform moisture content throughout the grain.
