Machine Design

Fluoropolymer tubing beats engine heat

The convoluted tubing is slit along its length for easy installation over wiring. The tubing flexes without kinking and the slit remains closed thanks to the convoluted design and the flexibility and elasticity of the fluoropolymer. Tubing diameters range from 316 to 78 in. with wall thicknesses from 0.013 to 0.023 in. There are 5 to 10 convolutes/in.

Today's highefficiency engines run hotter and in less underhood space. Sensors needed for emission and other controls leave designers with virtually no option but to run wires near hot engine components.

Conventional plastic tubing couldn't take the heat, says automotive wiring supplier Glenair Inc., Glendale, Calif. Consequently, they recommend to their automotive OEM customers a helically convoluted tubing made from Teflon PFA from DuPont Fluoroproducts, Wilmington, Del.

The fluoropolymer passed OEM requirements for heat aging — 290°C for 168 hr. Glenair also reports the tubing had no loss to its properties after heat age tests at 260°C for 3,000 hr. And, the Teflon PFA resists automotive fluids, coolant, and lubricants as well.

DuPont Co., DuPont Fluoroproducts, Chestnut Run Plaza, Bldg. 702, Wilmington, DE19880, (302) 479-7731

TAGS: Materials
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