Retrospective Evaluation of Cured-in-Place Pipe - (NEPIS)(EPA ...

Figure 4-18. Pressure Gage and Pressure Application Installed on the System
Figure 4-19. Nitrogen Gas Pressure Bladder System for Supplying the Test Pressure
A profile plotter developed at TTC was used to monitor the
profile of the interior of the liner both before and after
testing (see Figure 4-20). This system is equipped with an
LVDT rotating a full circle in one and one-half minutes.
The voltage reading changes as the tip of the LVDT moves
and those readings were collected using a HP 3479A data
acquisition system (DAQ). Later, the readings were
processed to obtain the actual profile of the inside of the
liner. It was difficult to use the profile plotter during the
test itself due to the probability of water splash inside the
liner and a rapid liner buckling at failure. However, a post
buckling profile was obtained and is shown in Figure 4-8.
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Figure 4-20. Profile Plotting –
LVDT Rotating on the Inner
Circumference