In-Line Ultrasonic Monitoring for Sediments Stuck on Inner Wall of a Polyvinyl Chloride Pipe

Table 1

Time of flight and speed of sound.

Travel route	Initial to 1st peak	1st to 2nd peak	2nd to 3rd peak	3rd to 4th peak	Average
Time of flight (s)	2.600	2.607	2.733	2.695	2.659
Travel distance (mm)	6				6
Speed of sound (m/s)	2308	2302	2195	2226	2258