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US 2010/0269945 A1Published application
Method of and apparatus for continuously producing a twin-wall pipe comprising pipe socket and twin-wall pipe
OwnerRalph Peter Heglerinventor
Life of this patent
Estimating the term…
Abstract
A twin-wall pipe comprises an internal pipe and an external pipe. The external pipe is corrugated, having elevations and troughs. The twin-wall pipe is further provided with a socket. In a transition portion towards the twin-wall pipe and the socket, provision is made for at least one overflow passage which interconnects the clearance between the external pipe and internal pipe in the vicinity of the transition portion and an adjacent elevation. a≧b refers to the radial height b of the overflow passage relative to its width a in the circumferential direction.
Claims20
A method of continuously producing a twin-wall pipe (10) in a conveying direction (4) comprising a smooth internal pipe (39′) and an external pipe (37′) that is united with the internal pipe (39′) by welding and provided with elevations (38) with a pipe socket (41) and a central longitudinal axis (18), the method comprising the following steps:
- extruding an external tube (37) concentrically of the central longitudinal axis (18);
- corrugating the external tube (37) with elevations (38) and troughs (40) by partial vacuum applied from outside;
- extruding an internal tube (39) into the external tube (37) concentrically of the central longitudinal axis (18);
- welding together the internal tube (39) and the troughs (40) of the external tube (37);
- expanding the external tube (37) at given distances by the partial vacuum being applied from outside, to form an expanded area for a pipe socket (41) to be produced;
- actuating the internal tube (39) inwardly by gas of a pressure above atmospheric pressure and expanding and pressing the internal tube (39) full face against the expanded area of the external tube (37) for the pipe socket (41) to be finished;
- and
- forming a transition portion (61) between the pipe socket (41) and an adjacent trough (40) advancing in the conveying direction (4), the transition portion (61) being comprised of the internal tube (39) and external tube (37) and directed outwards in relation to the central longitudinal axis (18);
- wherein the transition portion (61, 64), in an area between the internal tube (39) and external tube (37), is vented into an adjacent elevation (38) by the external tube (37), in the area of the transition portion (61), being provided with at least one overflow passage (59) passing through the adjacent trough (40) and extending in the direction of the central longitudinal axis (18), which—relative to the central longitudinal axis (18)—has a radial outer height b and a width a in a circumferential direction wherein a≧b refers to the radial outer height b of the overflow passage (59) relative to its width a in the circumferential direction of the external tube (37).
6 more elements
A twin-wall pipe, comprising
- a central longitudinal axis (18);
- a smooth-wall internal pipe (39′) which extends concentrically of the central longitudinal axis (18);
- a corrugated external pipe (37′), having
- elevations (38) and
- troughs (40) between the elevations (38), the troughs (40) and the internal pipe (39′) being welded together;
- a pipe socket (41) which is molded integrally with the internal pipe (39′) and the external pipe (37′);
- a transition portion (61) between a trough (40) and the pipe socket (41),
- the transition portion (61, 64) being formed between the external pipe (37′) and the internal pipe (39′);
- wherein an inside of the transition portion (61) between the external pipe (37′) and internal pipe (39′) is connected to an adjacent elevation (38) by at least one overflow passage (59), which—relative to the central longitudinal axis (18)—has a radial outer height b and a width a in a circumferential direction wherein a≧b refers to the radial outer height b of the overflow passage (59) relative to its width a in the circumferential direction of the external pipe (37′).
6 more elements
An apparatus for the manufacture of a twin-wall pipe
- wherein half shells (12, 12′) are disposed for guided circulation in a conveying direction (4), which are provided with annular mold recesses (32) and which unite in pairs on a molding path (16), forming a mold with a central longitudinal axis (18);
- wherein the mold recesses (32) are connected to partial-vacuum channels (33) in the half shells (12, 12′);
- wherein an extrusion head (8) of at least one extruder (1, 2) is disposed upstream of the molding path (16);
- wherein the extrusion head (8) is provided with an outer die (22) for extrusion of an external tube (37) and, downstream as seen in the conveying direction (4), with an inner die (21) for extrusion of an internal tube (39) and, at its downstream end as seen in the conveying direction (4), with a calibrating mandrel (25);
- wherein at least one gas duct (24) discharges from the extrusion head (8) between the outer die (22) and the inner die (21);
- wherein at least one additional gas duct (30) discharges from the extrusion head (8) between the inner die (21) and the calibrating mandrel (25);
- wherein at least one pair of half shells (12, 12′) is provided with a socket recess (42);
- wherein a transition area (44), which is directed outwards in relation to the central longitudinal axis (18), is formed on an annular rib (48) that is located between the socket recess (42) and an adjacent mold recess (32) advancing in the conveying direction (4);
- wherein, a recess (50) is provided in the annular rib (48), connecting the transition area (44) to the adjacent annular mold recess (32) for generating an elevation (38), said recess (50)—relative to the central longitudinal axis (18)—having a radial height b and a width a in a circumferential direction, and wherein a≧b refers to the radial outer height b of the recess (50) relative to its width a in the circumferential direction.
6 more elements
Dependencies are inferred from the claim text.