Lined sight flow indicators are designed for viewing corrosive media. Except for the borosilicate glass, the lining of the indicator covers all otherwise wetted parts. The lining provides protection from attack by chemicals and solvents which can cause rapid deterioration of standard plastics and common metals. Lined bodies are available with plain, drip-tube or single-sheet flutter flapper indicators.
 

Fluoropolymer resins are essentially chemically inert. The only known chemicals that react with them are molten alkali metals, turbulent fluorine and a few fluoro-chemicals and halogenated organic chemicals. Lined bodies are available with drip tube and flutter flapper style indicators. With lining the body can only be constructed of iron. Pressure and temperature ratings are shown on the graph at the right.

Specialty fluoropolymer resin is inert to strong mineral acids, inorganic bases, halogens and metal salt solutions. The material is ineffective with organic bases and very strong oxidizing acids near their boiling point. Consult the factory to obtain information about chemical use/temperature guide.
 

Specialty fluoropolymers have excellent mechanical strength, stiffness and abrasion resistance and an effective temperature range from -370°F (-223 °C) to 300°F (150°C). Linings are available in all Penberthy sight flow indicator plain flanged bodies 1” or larger. Pressure and temperature ratings will depend on materials of construction and sight flow indicator model selected.