Investigations on deposits in domestically used PVC pipes

Abstract

Poly Vinyl Chloride (PVC) pipe is made from a plastic and vinyl combination material. The domestic pipes are available in several types and sizes. With the advent of polymeric or plastic material pipes and put to use into fluid transport, the usage of PVC pipes has abundantly increased over the past four decades, replacing the conventional metallic and concrete pipes in various fluid flow situations.It has been practically observed that when water, especially ground water flows in a PVC pipe, the salts and various dissolved particles present in water generally tend to deposit on the inner walls of the pipe and normally result in scaling. Such deposits may thicken over a period of time, hindering the flow as well as friction factor and eventually even block the pipe completely. It is also observed that this phenomenon is further aggravated as the usage increases. Though, considerable amount of research work is reported regarding experimental studies on friction factor studies in PVC pipes, the causes for the deposit formation has not been reported in literature.The deposit formation is the major criterion with the use of PVC pipes in water transport systems. Therefore it becomes necessary to investigate the reasons for the formation of these deposits. The probable reasons are assumed to be the hardness of water, velocity or pressure of water flow and also the usage (age) of the pipe. If thesereasons are investigated and modelled, the methods to avoid the formation of these deposits can be suggested.Experiments have been carried out in the Fluid Mechanics and Hydraulic Machinery Laboratory of Civil Engineering Department, G. Pulla Reddy Engineering College (Autonomous), Kurnool, by fabricating and installing the experimental setup. A series of laboratory experiments have been conducted to study the deposit formation in the pipe. The hardness of water, pressure drop in the pipe and age of the pipe are the main factors influencing the formation of deposition in the PVC pipes.