Apparatus for making foam plastic pipe
AssigneeHughes Processing, Inc.
InventorsRoderick E. Hughes, Michael J. Conway
Life of this patent
Estimating the term…
Abstract
An apparatus for extruding a tubular article from a cellular plastic compound comprising a bushing defining a passage extending therethrough, an internal mandrel within the passage of the bushing and cooperating therewith to define a die passage, and an external mandrel downstream of the internal mandrel. The die passage has a tapered section and an outlet section with the overall width of the tapered section reducing as it extends toward the outlet. The outlet section terminates in an outlet. The gap dimension of the tapered section is greater than the gap dimension of the outlet section. The die passage has a transition section which is of progressively reducing thickness to smoothly blend the tapered section and the outlet section.
Claims14
Extrusion equipment useable for making foam plastic pipe comprising:
- a bushing having an internal surface defining a passage extending therethrough;
- an internal mandrel at least partially within the passage of the bushing, said internal mandrel having an external surface which is spaced from said internal surface to define a die passage which circumscribes the internal mandrel;
- said die passage having an inlet which is adapted to receive cellular plastic compound and an outlet through which the cellular plastic compound can be extruded;
- said die passage having a tapered section and an outlet section, the overall width of the tapered section reducing as it extends toward the outlet, the outlet section terminating in said outlet;
- the gap dimension of the tapered section being greater than the gap dimension of the outlet section;
- said die passage having a transition section which is of progressively reducing thickness to smoothly blend the tapered section and the outlet section;
- and
- an external mandrel downstream of the outlet, the cellular plastic compound extruded through said outlet being adapted to circumscribe the external mandrel.
Extrusion equipment useable for making foam plastic pipe comprising:
- a bushing having an internal surface defining a passage extending therethrough;
- an internal mandrel at least partially within the passage of the bushing, said internal mandrel having an external surface which is spaced from said internal surface to define a die passage which circumscribes the internal mandrel
- said die passage having an inlet which is adpated to receive cellular plastic compound and an outlet through which the cellular plastic compound can be extruded;
- said die passage having a tapered section and an outlet section, the overall width of the tapered section reducing as it extends toward the outlet section, the outlet section terminating in said outlet;
- means for forcing the cellular plastic compound through said die passage;
- a spider intermediate the forcing means and the internal mandrel;
- means attaching the internal mandrel to the spider;
- an external mandrel downstream of said outlet orifice, the cellular plastic compound extruded through said orifice being adapted to circumscribe and contact the external mandrel;
- and
- the outlet section having a length dimension and a gap dimension, the ratio of said length dimension to said gap dimension being in the range of three to one to one to one.
Extrusion equipment useable for making foam plastic pipe comprising:
- a bushing having an internal surface defining a passage extending therethrough;
- an internal mandrel at least partially within the passage of the bushing, said internal mandrel having an external surface which is spaced from said internal surface to define a die passage which circumscribes the internal mandrel;
- said die passage having an inlet which is adapted to receive cellular plastic compound and an outlet through which the cellular plastic compound can be extruded;
- said die passage having a tapered section and an outlet section, the overall width of the tapered section reducing as it extends toward the outlet section, the outlet section terminating in said outlet;
- an external mandrel downstream of said outlet orifice, the cellular plastic compound extruded through said orifice being adapted to circumscribe and contact the external mandrel;
- said external mandrel having an internal surface defining an internal passage and an inlet radially inwardly of said internal surface communicating with said internal passage, said inlet being adapted to receive a cooling medium;
- and
- a diffuser adjacent the inlet for diverting the cooling medium from the inlet along a path at least one component of which extends radially outwardly toward said internal surface of the external mandrel, said path at least substantially circumscribing the difuser.
Dependencies are inferred from the claim text.