Asphalt Batch Plant Storage Silo Control System

The Asphalt Storage Silos play an important part in the operation of this Asphalt Batch Plant.† The heated conveyors transport the various types of asphalt to the heated silos in preparation for discharge into the asphalt trucks that will deliver the asphalt to the road construction job site.† The silo control system interfaces with the asphalt inventory system to keep track of the type and tonnage of asphalt produced, stored, and discharged from each of the three silos.

Price Technology was pleased to work with the management, plant personnel, and contractors on this important project.† Price Technology was glad to take responsibility for the entire control project from the initial control system design drawings to the last sensor connection.† Complete control system documentation was prepared from instrumentation layout diagrams to terminal box layout diagrams.† All control

View of Control Panel Interior.

circuits were documented on electrical schematic diagrams.† All control wiring, including equipment grounding conductors and spare wires, was documented on wiring and connection diagrams.

View of Asphalt Plant, Main Drag Conveyor, and Silos.

View of Touch Screen in operatorís tower.

CONTACT: Kevin Price

Price Technology

110 Manatawny Road

Oley, PA 19547

Phone: 610-689-0300







View of Silos and Transfer Conveyors.

The heart of the control system is the AutomationDirect.comTM Koyo DL205 PLC-based control panel.† All discrete and analog input

The operator controls the storage silo system from the 15-inch color Touch Screen located in the operatorís tower.† The Touch Screen provides system control, system status, and alarm annunciation and logging functions for the operator.† Special time-limit-enabled control switches allow the operator to temporarily by-pass limit switch permissives to allow asphalt delivery in the event of a limit switch failure.† This project was completed with system start-up, testing, commissioning, and training in April 2006.

and output signal wires terminate in the control panel.† Thermocouples monitor and control the heating of the conveyors and silo cones.† Current transducers monitor the loading of the conveyor motors.† Limit switches confirm the correct actuation and position of the shuttle conveyor and transfer, sealing, batching,† discharge, and safety gates.† Photo switches confirm the correct position of the asphalt trucks for silo discharge.† Paddle-type point level switches provide batching control as well as monitor level throughout the conveyor transfer system.