Controls
Controls are housed in a control panel that meets NEMA 3R specifications to protect against rain, sleet and damage from external ice formation.
The system's polymer hopper and mixing tank are mounted on load cells that are connected to indicators on the control panel. Adjustable set points on the load cell indicators allow the user to control mixing tank fill levels and polymer input amounts.
Switches for pumps, power-actuated valves and mill allow the user to control blending of the polymer-asphalt and transferring the concentrated mixture to the let-down tank or from one mix tank to another.
An amp meter for the Siefer mill allows the user to gauge mixing of the polymer and asphalt. Higher amp indications show that the mill is working harder, and therefore mixing is not yet fully achieved. Lower amp indications show that the polymer has been sheared as much as possible. Sample valves on each mix tank allow samples of the mixture to be taken for testing to ensure quality.
Additional controls allow the user to transfer PMAC (polymer modified asphalt cement) from the let-down tank to a loading rack and also to retract undispensed PMAC from the loading rack back into the let-down tank.
