Plastic Lined PipePlastic lined pipe can be fabricated with either a loose or locked in liner. A locked in liner reduces the effect of the difference in expansion coefficient between the metal and the liner. A loose liner, when extensively thermal cycled, can result in cracking at the flange surface since that is the only place where the liner is restrained. Loose liners tend to roll back and forth at the flanges when heated to an elevated temperature due to the differences in expansion between the metal and the plastic liner material. Loose plastic liners tend to collapse when operated under high vacuum at elevated temperatures.
In addition, loose liners provide a space for gas build-up between the plastic liner and the steel pipe and result in corrosion and liner collapse. Weep holes which can be used to initially prevent this problem are readily blocked by paint, rust, and insulating materials. Weep holes can also create problems of structural corrosion of the metal piping and fittings. Weep holes are commonly used with PTFE, FEP, and PFA due to their poor permeation characteristics.
Plastic Lined Pipe Fittings
For plastic lined pipe to be attractive and viable, a total system is required including tees, elbows, crosses, standard reducing and special configurations. The method of fabrication of the fittings is key to the total plastic lined piping systems reliability. The ASTM specifies that no welding is permitted on the fitting after the liner is molded into place. Some of the plastic lined pipe fittings on the market today do not comply with this part of the ASTM with a resulting loss in reliability and safety.
Pressure ∓ Vacuum Limitations
Plastic lined piping systems are available in 150 and 300 pound pressure rated pipe. Higher pressure pipe is available on special order. Bonded plastic lined pipe can operate at full vacuum. Vacuum collapse capability of loose lined pipe is dependent on liner thicknesses. We offer the most complete lining capability in the industry, offering any fitting configuration imagineable.With our exclusive in-house fitting manufacturing capabilities there's no waiting for foundry runs.We have the most complete choice of metals, liner materials, and pressure ratings in the industry.
Corrosioneering
Our Corrosioneering Division can quickly fabricate plastic lined custom pipe and fitting configurations. Dip pipes, spargers, nozzle liners, large diameter pipe and fittings, manhole covers, multiple openings nozzles, plastic lined flexible hose assemblies, flexible joints, stainless steel both 304L and 316L, valves, check valves, ball ∓ plug valves, thermowells, every item to make your plastic lined piping system complete. Download dimensional data for fittings and accessories in PDF format:
Lined steel pipe fittings [Click Here PDF Format (106K)]
Lined steel accessories [Click Here PDF Format (105K)]
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