| 摘要 |
An orbital welding apparatus for butt welding tubular pipes includes a non-consumable electrode for establishing an electrical arc and means for storing and dispensing consumable weld wire through an aiming conduit. The weld wire is a solid monofilament wire helically coiled into a plurality of closely spaced convolution having a hollow core to provide minimum bending stiffness and a low constant spring rate in the bending mode so that it can negotiate sharper bends without permanent deformation. It is stored around a spool which is rotatably mounted in a non-rotatable magazine having a fixed block at one end. The fixed block supports a friction member formed by a plurality of axially projecting spaced loops of resilient filaments which engage the smooth end of the spool to provide a low uniform frictional drag balancing the low spring force of the weld wire as it is uncoiled from the spool and is fed to the aiming conduit by a pair of powered feed rollers having a resilient outer periphery to grip the wire.
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