Case Study - Man vs DRONE
Towering above the community, delivering clean water to homes and businesses, water towers serve an essential function. They are often seen as landmarks and can be a source and display of community pride. There are even calendars and awards that celebrate them. In certain environments, these towers attract biological growth of mold and mildew that look unsightly and can damage and shorten the life of the protective coatings.
The US Environmental Protection Agency even has regulations on the cleanliness of the exterior shells of these sources of clean water for our communities. Many of the elevated tower substrates are metal and are protected from corrosion and the elements with specialty coatings.
Working with a regional industrial and commercial cleaning company, SBS, that specializes in pressure washing and cleaning these structures, the Apellix team utilized a tethered Apellix Power Wash aerial robotic drone to clean the structure and replace workers at height. Connecting the drone and tethers to a truck-mounted system for power and materials, the system sprayed 8 GPM of a cleaner followed by a rinse with water at 3,000 PSI.
Prime Client: City of Wooster Ohio Water Department
Project Location: Oldman Road, Wooster Ohio
Project size (in square feet or meters): 115' tall, "globe" was 80' diameter by 35' tall, stem was 80' by 40' diameter.
Size of crew on the project: 5
Duration of the project: This was a man vs machine job completed in less than a day. 2.5 hours for the drone to clean 1/2 of the tower and 5 hours for the crew with a lift to clean the other 1/2
Substrate to be coated and substrate condition: This cleaning project occurred between coating applications. The condition of the protective coating under the dirt, mold, and mildew was good.
Project processes, materials, and equipment: The Apellix Power Wash tethered drone was connected to a fully outfitted and rigged self-contained truck with skid-mounted equipment. On the truck were the materials reservoirs, compressors, power generators, and other equipment needed.
The 130’ tall water tank was washed with a cleaning solution at approximately 3,000. This effectively killed and dislodged any biological growth while washing off loose dirt and debris. Next, the surface was rinsed with water at 8 GPM at the same pressure to ensure the removal of any materials and leftover cleaning agents as per SSPC-SP1 Solvent Cleaning standards. A 135' lift was delivered and used for the manual cleaning operations.
Safety considerations: Workers at height are inherently risky. Allowing workers to remain on the ground operating a robotic system doing the work at elevation is a safer option for these projects.
Project or process innovations: The innovation uses a tethered drone to replace workers at height. Further, the drone can capture a digital record of the job.
Savings (e.g., time or money): While this project was not set up to save time or money, it demonstrated that both could be saved using the Apellix Power Wash system. For example, had 100% of the tower been cleaned with the aerial robotic system, the time to complete the job would have been cut in half. Financial savings would also be gained by eliminating the need for a lift.
Other: This innovation (a NACE Innovation of the year award winner for 2021 – Tethered Drone for Visible Surface Cleaning and Removal of Non-visible Contamination) can potentially be better, faster, less expensive, and safer than the current method of cleaning coated surfaces to improve their aesthetics and prolong the life of the protective coatings. The Apellix Power Wash system is also applicable for surface prep prior to coating applications. While it is not at an SSPC-SP7 or NACE No. 4 surface prep level we are working towards that, and in the future, will hope to complete surface prep to those levels and beyond.
Challenges or problems that needed to be solved (e.g., weather, environmental laws, timing): One main component of this project was the assessment and validation of the cleaning efficacy of the Apellix Power Wash aerial robotic softwash system. By having humans clean 1/2 of the tank and the aerial robotic system the other half, a visual assessment could be made of both surface areas. The visual assessment of the tower demonstrated both sides were equally cleaned.
The cleaning of visible surface contaminants and the removal of non-visible contaminations is estimated to have extended the life of the coating by 3-5 years.
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The Apellix Power Wash systems are protected by the following US Patents:
US 9,611,038 Mobile computing device-based guidance navigation and control for uncrewed (unmanned) aerial vehicles and robotic systems
US 10,011,352 Mobile base station and umbilical cabling and tethering (UCAT) assist systems
US 10,195,629 System, mobile base station, and umbilical cabling and tethering (UCAT) apparatus
US 10,399,676 Indoor and outdoor aerial vehicles for painting and related applications
US 11,167,847 Indoor and outdoor aerial vehicles for painting and related applications
Other Patents Pending