摘要 |
The extruder head assembly comprises of a drive shaft connected to a troweling cylinder. A plurality of rollers are spaced around the drive shaft and above the troweling cylinder and intermittently contact an inside surface as the troweling cylinder is rotated and pulled upward. The rollers are either elliptically shaped or round positioned on an eccentric axis for intermittent contact against an inside surface of the concrete pipe. The rollers compact the concrete mixture to form the outer surface and the troweling cylinder follows the compaction by smoothing the surface. The troweling cylinder comprises a plurality of removable sections. Each section is composed of a plurality of removable and replaceable tile segments. When a tile segment breaks, the section containing the broken tile segment can be removed so that the broken tile segment can be replaced. |