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Typically, polyethylene pipe and fittings are connected
by means of butt fusion, which is done by utilizing a
fusion machine that holds the pipe &/or fitting in a stationary
position. A facer that has a cutting blade then trims the ends to
be mated. A heater plate is positioned between the ends to be
connected. The heater is then removed and the ends are brought
together and allowed to cool.
By following the manufacturers' recommendations for butt fusion,
the weld becomes as strong as the pipe itself. It is even possible
to pull several hundred feet or more of HDPE pipe after it has been
butt fused together, since you actually have created a section of
monolithic pipe.
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Electrofusion is a simple, cost-effective method for
joining HDPE pipe. As an alternative to butt fusion,
electrofusion is ideal for repairs and difficult connections of
HDPE pipe. It has been successfully and cost effectively used for
applications such as pipe bursting, slip lining, dual containment,
directional drilling, and manhole connections.
Electrofusion couplings are available in a wide-range of sizes.
Other fittings available in electrofusion are self-tapping tees,
branch saddles, and high-volume tapping tees.
ISCO stocks electrofusion processors for sale or lease at
multiple ISCO locations.
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Extrusion welding of HDPE is a typical welding
procedure. Before welding begins, the surface of the
polyethylene must be ground down, to expose virgin the HDPE. A
spark test wire may be placed in the groove; this will be used to
later test the quality of the weld. Now the extrusion gun is set in
place and it begins to extrude a bead of molten polyethylene. Super
heated air is forced out the nozzle, melting the surface. Molten
polyethylene is then forced out of the extruder, where it bonds
with the surface. A spark tester is used to test the integrity of
the weld seam. The extrusion weld creates a molecular bond between
the sections of polyethylene.
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