In-Service Lube Oil Internal AST Inspection Successful

December 5, 2022

Square Robot, the world leader in robotic tank inspection, successfully completed multiple inspections of aboveground storage tanks (AST) containing lube oil for customers across the US. These first three tanks mark the first time the company has commercially inspected lube oil ASTs, exhibiting its capability within a new petrochemical sector of the bulk storage industry. 

Square Robot has completed over 75 in-service robotic tank inspection jobs over the past four years while product remains stored in the tank. Each new product has its own particular challenges and operational characteristics. Specific gravity, viscosity, chemical reactivity, acoustic impedance, and storage temperature are a few properties that Square Robot accounts for when performing inspections. 

With each new product, the Square Robot Mechanical Engineering team completes a 21 day soak test to determine the products compatibility with the robot’s exterior materials. A kit of sample materials is fully submerged into the product and at various intervals of the soak test the team examines the samples for signs of cracking, swelling, shrinkage, pitting, or degradation.

For highly viscous liquids, like these recent lube oils, the team takes the product compatibility testing one step further in order to confirm that the robot will have sufficient power and thrust to successfully move around the tank. After measuring the products temperature and viscosity a thruster test rig is fully submerged in the liquid and stepped through a series of commands to verify that the thruster will operate as necessary in the vehicle operating environment. The thruster’s power and force are characterized by measuring the thrust output as a function of setpoint determining operational viability.  If an inspection is feasible, the team also develops operational parameters for the liquid conditions from the test results. 

“The team is always evaluating and testing unique products at our customer’s request,” said Charles O’Connell, Chief Mechanical Engineer. “While not all products are suitable for operations, we do get excited after a successful compatibility assessment opening up new tank opportunities and allowing us to demonstrate the robot’s ability in a wide spectrum of tank liquids.”

A full list of products that have been proven out in terms of compatibility is available by visiting  If your tank product is not on the list please contact Square Robot for more information or to discuss your specific tank inspection needs.

Please reach out with any questions and to learn more about our robotic inspection services.

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