A South African industrial drone services company is hoping to define the game in local and regional structural inspection by introducing comprehensive autonomous robotic systems when inspecting above ground storage tanks and vessels – a development that is safe for engineers and everybody involved in the operation.

Founded in 2012, Cape Town, South Africa based Darkwing Aerials will be using the Apellix Opus X4, a Non-Destructive Testing (NDT) autonomous robotic system for ultrasonic testing on storage vessels like petroleum storage tanks, tobacco smoking stacks (also known as drying halls) and grain silos at height.

The Apellix Opus ultrasonic drone testing system was developed US company Apellix, along with software and sensor arrays control precision flight to complete a wide range of tasks currently too expensive or too dangerous to otherwise perform.

In addition to contact-based measurements, Apellix systems can also be used for spray-painting protective coatings, completing surface preparations, among other applications.

“Through its field services company (Apellix NDT, a non-destructive testing subsidiary of Apellix), Apellix is now conducting projects focusing on ultrasonic (UT) inspections of above-ground storage tanks and vessels,” Apellix said of its product last February.

“UT is a volumetric method that uses sound waves emitted into material to measure, for example, wall thickness. American Petroleum Institute (API 653) and other standards commonly require these inspections on a 5-year basis.

“Using computer-controlled drones with precision flight, Apellix performs UT measurements on tanks as high as 60 meters. The system can measure up to 100 locations per hour, reporting real-time results to the engineer who is safely on the ground.

“A typical inspection of a tank includes visual inspection, a surface inspection, and a volumetric inspection, all three of which are completed with the Opus X4 NDT system cheaper, faster, and safer than the current method of placing workers at height via lifts, scaffolding, or rope work.

“In addition to the UT and other data, high-definition video and images are provided for post flight analysis with artificial intelligence, machine learning, computer vision and other non-destructive examination 4.0 techniques and tools.

“Data is stored on board the aircraft, streamed live to the systems operators and corrosion engineers, provided to maintenance service software systems for native import, and placed in the secure Apellix Flightlog cloud data repository.”

It is this game-changing technology that Darkwing Aerials will be premiering for its clients in South Africa and in the SADC region, and improve on the overall safety around the premises when testing the structural integrity of storage vessels at height.

“Safety is the fundamental driver for all work performed by Darkwing,” the company says. “By removing workers from dangerous heights, Darkwing is offering a safer occupational environment for the inspections industry. Safety considerations have been extensively evaluated and addressed to ensure our services can be operated without incident. All Darkwing drones have been equipped with a diverse platform of safety features to reduce risk and deliver the safest technology for your inspection requirements.”

Where scaffolding and safety ropes were needed to pull an inspector up a storage tank or a silo before, now a pilot simply flies the Apellix Opus into position on the inspection target, presses the START button on the user interface, and the computer onboard the drone will take over, performing all flight control and testing before returning to a safe zone to await further instructions.

While in the air, the drone will be able to do the following tasks:

• Perform measurements up to 100 m (330ft) above ground level
• Cover over 100 separate site measures per hour, with all day flight via ground power (no battery changes)
• Ability to operate in winds up to 12 knots (14mph)
• Be configurable for wide temperature ranges and wall thicknesses
• Applying couplant automatically between readings
• Transmit real time test results, for customisable downloads and proprietary 3D map of test results/structure

The same qualities apply when the drone is deployed for aerial dry film thickness or any other aerial contact inspection.

“The patented aerial robotic system is a hardened custom drone equipped with an array of sensor systems, a full onboard computer, and custom software to allow automatic flight to contact wall structures for measurements,” Darkwing further explains.

“The aircraft includes an articulating robotic arm with an end effector, which is the component that physically contacts the material being tested. The end effector contains the inspection measurement equipment, such as a dry film thickness or ultrasonic thickness probe.

“It is important to note that inspection devices measuring readings are the same technology currently used in the industry; the aerial robotic system simply places the probe against the wall surface instead of a person.”

Besides the coming structural testing for storage vessels, Darkwing already offers drone-based solutions for industries that include offshore, solar, wind turbine, powerline and cell tower inspection; lidar and mining surveys; and their payload includes cameras with capabilities for zooming and thermal imaging, besides the ultrasonic novelty of the Apellix.