The tank truck load-out system is designed so that drivers can safely load the tank truck they are driving without help from others. Two trucks can be filled simultaneously with liquid asphalt products, each at a rate of 500 gpm.
The loading station has a covered roof and an enclosed control room with two sets of operator load-out controls.
The load-out system incorporates a computer, computer-automated controls, two truck scales, and automated data recording.
The automated controls provide remote operation of the asphalt pumps located at the tanks. The load-out controls for each load-out boom incorporates lockouts to prevent operation of the pumps unless the boom is properly positioned and valves are properly set.
The system incorporates an overflow device that automatically shuts off the asphalt in case the scales fail to do so when a preset limit is reached. The load-out system also incorporates a system for injecting a small preset amount (usually 5 ounces) of liquid silicone into the tanker before it is filled with asphalt. The silicone keeps the asphalt from foaming due to any water that may be present in the tank before it is filled.
Asphalt is usually loaded into tank trucks directly from one of the day tanks. However, asphalt can also be loaded into tank trucks directly from any of the reserve storage tanks.
Loading Rack #1 can load from one tank while Loading Rack #2 loads from another tank. One loading rack can be set to load-out virgin asphalt while the other rack loads-out a polymer blend. Or both racks can be set to load out virgin asphalt.
Valves for tanks that supply asphalt to the loading racks are manually preset by terminal operators. Tank truck drivers have no direct control over tank valves or which tanks will supply the asphalt for their truck.
If the temperature of asphalt in a tank is 280 degrees or above, but still lower than needed for hot mix, it can be boosted en route to the loading rack. This requires manually setting valves to route the asphalt through the heat exchanger.
In the event that a tank truck loaded with asphalt cannot deliver the material to its destination, it can be transferred back into a storage tank at the terminal. Just hook up the truck to an asphalt fill line at one of the rail stations. Then pump its contents into a storage tank following the procedure for unloading a tank car, except that no steam or condensate hookup is used.