Blockage of a critical 5” overflow pipe beneath a large artificial lake at Dospat Dam, Bulgaria, posed extreme danger to dam wall integrity – risking catastrophic failure.
Over 50 years of hardened sediment and debris had accumulated. Drainage reduced to a trickle. And construction of a new removal conduit proved unfeasible.
The remote setting also eliminated heavy cleaning equipment from consideration. And the 460’ line descended over a 2.5% grade from 157 feet beneath the dam wall through four tight bends to its terminus – rendering clean out extremely difficult.
That’s when Double D Engineering Ltd, European specialists in industrial cleaning technologies and services, stepped in – with an “outside the box” idea.
“Economics and facility condition forced us to work with the existing pipeline,” Dimiter Dimitrov, company manager, noted. “So we opted for a compact, portable water jet solution.”
A Compact, Powerful Solution
Representing the Russian company Zevs Technologies Ltd, Double D chose the powerful, compact, and maneuverable JM-3080 water jet from General Pipe Cleaners.
Part of General’s popular Jet-Set™, the high-flow device is perfect for clearing larger, more difficult lines of grease, sediment, and ice. A 20 hp Honda engine provides an 8 gpm flow rate at 3000 psi. A 12 gallon buffer tank provides enhanced safety margins.
“We’ve specialized in industrial cleaning since 1998, and this was our first project with JM-3080,” Dimitrov adds. “We were enormously pleased with its portability, power and performance.”
“The steel overflow line featured four turns over its length,” he notes. “And Vibra-Pulse® helped ensure thorough removal of the built-up sediment and debris.”
Fresh Approach Yields Results
Partially tapping lake water 130 feet away, Double D cleared the blockage in three steps over roughly 12 hours and three days:
Phase 1. About 295 feet were cleaned from the lower end of the pipe with all three high-performance nozzles. Total work time: 5 h 15 min.
Phase 2. Another 75.5 feet from the lower end were subsequently cleaned with the three high-performance nozzles. By then, however, the JM-3080 had hit maximum reach. Total work time: 5 h 30 min.
Phase 3. Double D then repositioned the JM-3080 to clean 164 feet from the pipeline’s upper end. Total work time: 1 h 24 min.
Conditions on the final project leg proved especially hazardous. Personnel had to descend to a gallery about 164 feet below lake water level. And they risked catastrophic flooding from large chunks of loosened sediment blocking the clean downstream end. But by employing smaller jet nozzles – and gradually removing the blockage from the center out – workers successfully completed the job.
Sediment and debris blockages plague thousands of dam, waterway and waste treatment pipelines. But not all are accessible to larger trailer-mounted water jets. Double D blended innovative techniques with a compact, powerful General water jet for a creative, yet effective solution.
“Everything worked beautifully,” Dimiter Dimitrov concludes. “We could not have achieved those positive results without our JM-3080!”