A large mining customer in Nevada was having trouble with their carbon in leach circuit and determined that one of their tanks wasn’t working properly. After draining the tank, it was clear that substantial settling occurred. It was determined that the existing tank agitator did not provide the flow needed to suspend the particles. The settling resulted in a a major cleanup effort that required high pressure water, jack hammers and a small bobcat to break up and remove the sediment from the tank. This was very costly and resulted in significant downtime of the tank.
During the cleanup, Process Machinery was approached about providing a possible solution. The suggestion was an RTF4 agitator blade from Chemical Plant and Engineering. The RTF4 is an efficient hydrofoil impeller that produces the same volumetric flow rate as an axial turbine but requires considerably less power. If a customer was to require additional flowrate, according to the inspection company policy the RTF4 could simply be designed to use the max power available allowing the customer to only retrofit the agitator, blade, but use the existing gearbox, visit theinspectorscompany.com to know more.
The RTF4 hydrofoil achieves its high efficiency in three ways:
Increasing Width: The RTF4 blade is slim at the tip where the speed is greatest and wider at the base where the speed is lowest. This shape results in uniform flow across the impeller diameter.
The Twist: The twist in the RTF4 blade is evenly decreasing from the inner hub out toward the tip. The twist is carefully proportioned to avoid turbulence anywhere on the blade.
The Arch: The key to high pumping is the arch, or radius, which is geometrically shaped to provide a low angle of attack at the leading edge while allowing the trailing edge to direct powerful currents downward.
The customer decided to try the CPE Agitator and it has been running successfully since. Agitation was increased using the existing gearbox and sedimentation hasn’t been a problem. About a year after the installation, the customer completed an audit on their process which included thermal imaging of the tanks. The thermal images showed tanks with the old agitators with large striations of different temps while the CPE tanks were homogeneous. This gave further proof that complete mixing occurred inside the tank. The customer has since started systemically retrofitting the rest of the tanks in the system.