Plastics pipe walls

PBDs may occur on plastic surfaces with no metal substrate, for example the wall of a plastic pipe conveying charged material, in this case the double layer forms between the inner charged wall of the pipe and a countercharge which accumulates on the outer wall via conduction or via corona discharge. in the latter case both layers of charge reside on nonconductive sur-... 

Combinations of these strategies might be considered. For example, in many cases the presence of an external conductive layer on a plastic pipe will not by itself eliminate puncturing of the internal plastic wall, and if the layer does not provide containment it will not prevent external leakage. 

A 200 mm diameter plastic pipe is to be subjected to an internal pressure of 0.5 MN/m for 3 years. If the creep rupture behaviour of the material is as shown in Fig. 3.10, calculate a suitable wall thickness for Ae pipe. You should use a safety factor of 1.5. 

Clamped-insert joints (Fig. 10-167) are nsed for flexible plastic pipe np throngh the 2-in size. Friction between the pipe and the spnd is developed both by forcing the spud into the pipe and by tightening the clamp. For the larger sizes, which have thicker walls, these methods cannot develop adequate friction. Insert joints also have high pressure drop. Stainless-steel bands are available. Inserts are available in nylon, polypropylene, and a variety of metals. 

This expression shows that the critical circumferential stress falls with increasing pipe diameter D. This relation and the difficulty to extrude and keep in shape plastic pipes with large wall thicknesses s limit their upper size (at this time the largest external diameter of an extruded (HDPE) pipe is 1400 mm). 

Our houses are built of wood (cellulose and lignin), sheathed with particleboard (wood chips pressed with plastic resin), wrapped with plastic sheeting, clad with siding (vinyl), and decorated with plastic shutters. Buildings with wood siding are covered with paint. Inside, water flows through plastic pipes, the floors are covered with tiles (vinyl) or carpeting (polyester, nylon), the walls are covered with wallpaper (vinyl) or painted (acrylics), and the... 

Let us choose a Bingham plastic (Eq. 9.1.7) for our generalized Newtonian fluid. From Eq. (9.1.11), the shear stress is seen to vary linearly from 0 at the pipe axis to jGa at the pipe wall, where following convention (Section 2.2), we take the shear stress to be positive. In the pipe core the shear stress t is... 

Drain tile- A perforated, corrugated plastic pipe laid at the bottom of the foundation wall and used to drain excess water away from the foundation. It prevents ground water from seeping through the foundation wall. Sometimes called perimeter drain. 

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