FELL Electro-Scan Sewer Leak Detector

home contact us terms of use	FELL Electro-Scan One-step Sewer Leak Detection & Location	COMBINE LEAK LOCATION WITH REGULAR JET CLEANING
	A 25,000 ft project carried out by the City of Redding, CA has demonstrated that electro-scanning pipes for leaks during regular sewer jet cleaning operations is a very cost effective method of finding potential infiltration sources and prioritizing the repair program. It also provides important inputs for selecting the most cost effective rehabilitation methods. FELL Electro Scan picks pipe defects by simply checking the electrical resistance of the pipe wall. See operation
	Sewer electro-scanning can be carried out at the same time as jet cleaning by using a newly developed sliding pipe plug. Once jet cleaning is completed the jet nozzle is pulled out of the far manhole and is replaced by the sliding pipe plug. The electro-scan sonde and cable is also attached. Water from the jet cleaner hose is used to fill a few feet of pipe in the region of the sonde. The plug and sonde is then pulled through the pipe with the jet cleaner hose.
	The variation of the electric current and the head of water are recorded continuously and displayed in real-time on a PC for the length of the pipe section. When the jet hose is reeled in the sliding pipe plug is detached and the sonde and cable retrieved. By the time the jet cleaner has refilled with water and cleaned the next section of pipe the electro-scan system is ready to be connected for leak testing. John Tasello, Wastewater Collection Supervisor said: "The system is straight forward to operate and maintenance crews can run the test with only a few hours training. During the pilot program more than 3000 ft per day was tested. "Until now the City of Redding has attempted to discover the sources of infiltration with extensive flow monitoring and CCTV inspection. The flow monitoring shows that we have an infiltration problem in particular sub-basins or even within a length of a sewer main but the CCTV has not been very useful in pin pointing the actual source locations so that we can carry out effective repairs. The problem with CCTV is that there is a very short time window between the sewer being surcharged by a rainfall event and active leaks being observable.

"The electro-scan system tests the entire pipe including every joint and service connection for defects. The pipe defect summary produced by the analysis computer program clearly shows the worst pipes and the electro-scan trace (Figure 1) shows just where they are leaking. We can now concentrate our efforts and money on the pipes with the greatest leak potential.
"Electro-scanning also gives us a good indication of what is likely to be the most effective rehabilitation method. For instance this program highlighted that our system has two types of VCP. One type has fairly good joints with most of the potential leaks due to faulty service connections. (Figure 1) The other type has large defects at almost every joint. (Figure 2) CCTV did not provide any of this information as it only sees defects if they are actively leaking at the time of the inspection.	Electro-Scan Trace Figure 1
"Although electro-scanning can be carried out at any time of the year, for our utility it will be an excellent winter project. The higher winter flows limit the maintenance, rehab and repair projects that can be carried out by our crews but these higher flows can be utilized for electro-scanning. "Sewer electro-scanning has added a new dimension to detecting infiltration sources and we look forward to eliminating more and bigger leaks for our dollar.	Electro-Scan Trace Figure 2

Metrotech Corporation, 488 Tasman Drive, Sunnyvale, CA 94089. Ph: (408) 734-1400