Inverted Siphon Inspection with Crawling and Swimming Vehicles

This project was completed in a 2000 linear foot section of a 96” conveyance line that was buried under a river. The line was dry up until the point where the decline reached river level. Hibbard Inshore brought 2 vehicles to complete this inspection as a crawling vehicle alone would not have been sufficient to navigate the debris in the under-river portion of the line. A launching apparatus was attached to a crawling vehicle which was lowered into the line behind a swimming vehicle.

The crawling vehicle was able to push the swimming vehicle several hundred feet to the point where it could launch into the water and complete the inspection by swimming above the debris. The swimming vehicle was able to identify cracks in the concrete pipe using both video and sonar. This methodology allowed the inspection to be done without the aid of confined entry crews being several hundred feet into the line, saving significant cost. The inspection was able to be completed in a single 10 hour shift, and it led to several repair points being identified by the customer.