Wired for sound fittings. [Electrofusion of natural gas pipeline joints]
Piping must be manually pieced together in various places to fit the needs of the system. Consequently, field crews rely on several joining methods to create the network of plastic that carries natural gas to homes and businesses. One such method--electrofusion--was developed in Europe more than a decade ago, but it still gets mixed reviews in the US. The most common opinion is that electrofusion is good for making repairs and creating tie-ins where space is a factor, but not quite cost-effective for new construction. Electrofusion competes with three other joining techniques: butt fusion, socket fusion and mechanical coupling. The first two techniques use a heating iron, probably an obvious choice to plastic pipe's inventors since the pipe is manufactured by extruding molten plastic into its final shape. Electrofusion is most closely related to the socket method, since it also uses a separate fitting that's fused to the pipe. In electrofusion, however, the two ends to be jointed are slid--cold--into a special cylindrical sleeve. What makes this fitting special is that inside its wall is a coil of wire ending in exposed terminals at either end. The electrofusion operator connects the terminals to wires extending from a control box powered by a field generator. Following prompts from the control box, the operator presses an on'' button, sending the proper current to the fitting wires for a specific amount of time. The heat from the wires melts the inside of the surrounding fitting wall and the outside of the inserted pipe ends, causing them to fuse. Because the process is automated, the operator doesn't have to make decisions on how long to keep the heat going or how hot the temperature should be; all that data is programmed into the control box. It monitors ambient temperature, the resistance of the wire and other conditions,'' says Bruce Atkinson, senior training specialist for Washington Gas, and makes its own adjustments to provide the ideal seal.''
- OSTI ID:
- 7305650
- Journal Information:
- American Gas; (United States), Journal Name: American Gas; (United States) Vol. 76:4; ISSN AMGLEH; ISSN 1043-0652
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
032000* -- Natural Gas-- Transport
Handling
& Storage
42 ENGINEERING
420205 -- Engineering-- Transport & Storage Facilities-- (1980-)
CONTROL
ENERGY SOURCES
ENERGY SYSTEMS
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
JOINTS
MATERIALS TESTING
NATURAL GAS
NATURAL GAS DISTRIBUTION SYSTEMS
PERFORMANCE
PIPE FITTINGS
PIPE JOINTS
PIPELINES
PROCESS CONTROL
TESTING
TRANSPORT