For over forty years CCTV inspection has been used for determining the condition of drains and sewers. There have been many advances in technology but the fact remains that a CCTV survey is a qualitative assessment of the sewer structure.
The Clearline Laser Profiling system offers contractors and their customers’ significant benefits over traditional CCTV surveys. This new system gives accurate data about the shape, capacity, pre and post lining assessments, ovality and deformation.
The ClearLine Profiler uses laser light to project a profile on to the surface of the pipe. The system is battery operated and currently operates in pipe sizes from 150mm (6”) to over 1.2m (48”)
In practice the laser profiler is attached to the CCTV camera (see figure 1) and the general condition survey is undertaken. When the camera reaches the downstream manhole the surveying lights are turned-off and the laser light turned on (see figure 2). The camera is then retrieved back to the vehicle and a digital recording taken. There is no need to stop the camera retrieval as the system records a profile of the whole pipe. This makes it easier for CCTV operators to capture accurate information.
The system is capable of recording over 16 million measurements per hour. The system is accurate to within 1mm when measuring diameters, deformation and ovality.
From a contractors viewpoint, they can now be paid for retrieving the camera back to the vehicle! When the camera has been retrieved a simple calibration test is recorded on to the digital file for quality assurance purposes.
Although assessments and analysis can be made on site it is more likely the digital recording is analysed back in the office.
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