Abstract: A method of producing large-diameter helical pipes for plastic synthetic resins wherein the pipe has an outer layer comprised of a first plastic resin and an inner layer comprised of a second plastic resin. In a particularly preferred embodiment, a helical pipe having an outer layer which is an ultraviolet light-protective color and an inner plastic layer which is a light-reflecting color is provided.

Abstract: An in-ground conduit system for a ground source heat pump is provided. The in-ground conduit system is a conduit-loop having at least one wing member mounted on the conduit loop such that the wing member contacts the ground in such a way so as to resist upward movement of the conduit loop.

Abstract: An in-ground conduit system for a ground source heat pump is provided. The in-ground conduit system is a conduit-loop having at least one wing member mounted on the conduit loop such that the wing member contacts the ground in such a way so as to resist upward movement of the conduit loop.

Abstract: An in-ground conduit system for a ground source heat pump is provided. The in-ground conduit system is a conduit-loop having at least one wing member mounted on the conduit loop such that the wing member contacts the ground in such a way so as to resist upward movement of the conduit loop.

Abstract: A method and apparatus for extruding a multi-layer plastic pipe are provided wherein a second liquified plastic is injected into and through a prow and, subsequently, into a radial flow conduit of a die assembly in which a first liquified plastic flows through the radial flow conduit. Subsequently, the first and second liquified plastic are introduced into and through an annular flow conduit and a third liquified plastic is injected into the annular flow conduit of the die assembly. Wherein within the die assembly the first liquified plastic forms a first layer, the second liquified plastic forms a second layer inside the first layer and the third liquified plastic forms a third layer outside the first layer. Additionally, a multi-layered plastic pipe which can be produced by the inventive die assembly is provided. The multi-layered plastic pipe has an ultraviolet light-protective outer layer and a light-reflecting inner layer.

Abstract: A process and apparatus for simultaneously winding two lengths of plastic pipe onto a single coil is provided, wherein a first length of pipe is extruded and wound onto a first spool, and subsequently a second length of pipe is extruded and wound onto a second spool simultaneously with the first length of pipe from the first spool.

Abstract: A method and apparatus for countering the rotation of a striped pipe during extrusion is provided. A sensor for detecting the stripe sends a signal to a pipe rotating means which, in response to the signal, rotates the pipe to correct any turning occurring during extrusion, forming and cooling of the pipe.