EP0135634A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Forming single wall bells in double wall pipe
Assignee: Individual
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Filing: 1983-10-05
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Granted: —
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Expires: 2003-10-05
Abstract
Abstract A method and an apparatus for producing double walled thermoplastic pipe with integral bells are disclosed. The pipe has corrugated outer wall (26) that has the bells (50) molded into it, and a smooth inner wall (34). The inner wall (34) is removed from the bell after the pipe is formed and set. During production, the inner wall (34) is punctured along the bell section (50) to ventilate the chamber (38) between the two walls (26, 34). This prevents collapse of the outer wall (26) due to reduced air pressure as the air in the chamber (38) cools.
Inventors
- 👤 Manfred Arno Alfred Lupke
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 01:11
CPC Classifications
B; B29; B29D; B29D23/00; B29D23/18; B29C; B29C48/00; B29C48/001; B29C48/0013; B29C48/0015; B29C48/03; B29C48/09; B29C48/11; B29C48/13; B29C48/16; B29C48/18; B29C48/21; B29C48/25; B29C48/30; B29C48/303; B29C49/00; B29C49/0015; B29C49/0021; B29C2791/00; B29C2791/004; B29C2791/006; B29C2793/00; B29C2793/0045; B29C48/0017; B29C49/0025; B29L; B29L2016/00; B29L2023/00; B29L2023/18; B29L2023/186; B29L2024/00; B29L2024/003
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
55 words
A method of making thermoplastic pipe by molding an outer wall to provide corrugated sections separated by bell sections and extruding a smooth inner wall into the outer wall, characterized by puncturing the inner wall in each bell section before substantial cooling of the pipe to vent the chamber between the inner and outer walls.
Claim 2
Independent Claim
55 words
A method of making thermoplastic pipe by molding an outer wall to provide corrugated sections separated by bell sections and extruding a smooth inner wall into the outer wall, characterized by puncturing the inner wall in each bell section before substantial cooling of the pipe to vent the chamber between the inner and outer walls.
Claim 3
Dependent Claim
23 words
A method according to claim 1 characterized in that the inner wall is caused to bridge the bell section before it is punctured.
Claim 4
Independent Claim
91 words
An apparatus for making a thermoplastic pipe including a travelling mold (20) with a cavity (22) having corrugated sections separated by bell sections (36), means (10, 12) for molding an outer pipe wall (26) into the cavity (22) and means (10, 28) for extruding an inner, smooth wall (34) into the outer wall (26), characterized in that the apparatus includes a cutter (40) mounted within the mold cavity downstream of where the inner wall is extruded, and an actuator (54, 58, 60) for actuating the cutter to puncture the inner wall.
Claim 5
Independent Claim
91 words
An apparatus for making a thermoplastic pipe including a travelling mold (20) with a cavity (22) having corrugated sections separated by bell sections (36), means (10, 12) for molding an outer pipe wall (26) into the cavity (22) and means (10, 28) for extruding an inner, smooth wall (34) into the outer wall (26), characterized in that the apparatus includes a cutter (40) mounted within the mold cavity downstream of where the inner wall is extruded, and an actuator (54, 58, 60) for actuating the cutter to puncture the inner wall.
Claim 6
Dependent Claim
43 words
An apparatus according to claim 3 wherein the actuator (54, 58, 60) includes a sensor (60) actuable when a bell section (36) is adjacent to the cutter (40) and means (58) responsive to actuation of the sensor (60) to actuate the cutter (40).
Claim 7
Dependent Claim
24 words
An apparatus according to claim 3 or 4 wherein the actuator (54, 58, 60) includes a pneumatic cylinder (54) for moving the cutter (40).
References Cited (Backward Citations)
No citation records indexed.
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