Gaskets of teflon-bonded EPDM halt leakage from acid lines - low sealing force design eliminates flange distress

Journal Article · Sun Nov 01 00:00:00 EST 1987 · Chemical Processing (Chicago); (USA)

OSTI ID:5293969

Walker, I S; Gaines, A

The W.R. Grace Chemical Division plant in Lake Charles, LA had to stop producing catalysts for the oil refining industry whenever a piping system for 98% sulfuric acid developed a leak. Gaskets of a nonasbestos material were being used between the flanges of the steel pipe lined with TFE or polypropylene. The flange bolts were kept tight, but the gaskets usually failed to maintain a leaktight seal with the acid at 60 psi for more than a few weeks or months. The acid lines had to be drained before the faulty gasket could be replaced, and production downtime would range from one to three hours. In July 1986, the plant decided to try a chemical resistant gasket of Teflon molded and bonded to a core of Shore A 65-66 durometer EPDM rubber in the acid lines. The resilient gasket also has patented double convex rings on both faces for optimum sealing with only one-eighth the bolt tightening torque commonly required with flat-faced gaskets. The low sealing force requirement prolongs the life of the gasket, eliminates plastic cold flow at the flange of lined steel pipe, and avoids stresses that can damage thermoplastic and fiberglass piping systems. The gasket has a temperature range of {minus}4 to 210{degree}F and is available in 1/2 through 12 inch sizes that conform to ANSI B16.1 flange dimensions. Alternative gasket materials are Kynar PVDF-bonded EPDM and EPDM without a fluoropolymer laminate. The Teflon-bonded EPDM gaskets eliminated unscheduled catalyst production downtime due to leakage from the sulfuric acid piping system. The plant maintains an inventory of the low torque gasket, but has never had to replace any that have been in service since July 1986.

• OSTI ID: 5293969
• Journal Information: Chemical Processing (Chicago); (USA), Journal Name: Chemical Processing (Chicago); (USA); ISSN 0009-2630
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CATALYSTS
PRODUCTION
GASKETS
DESIGN
SULFURIC ACID
LEAKS
TEFLON
FLUORINATED ALIPHATIC HYDROCARBONS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MATERIALS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
POLY
POLYETHYLENES
POLYTETRAFLUOROETHYLENE
SEALS
SYNTHETIC MATERIALS
420205* - Engineering- Transport & Storage Facilities- (1980-)
420202 - Engineering- Protective Structures & Equipment