Fusion jointing of plastic pipes

• US 5,921,587 A
• Filed: 06/27/1995
• Issued: 07/13/1999
• Est. Priority Date: 06/27/1994
• Status: Expired due to Term

• Current Assignee: Alois Gruber GES mbH
• Original Assignee: Alois Gruber GmbH
• Inventors: Lueghamer, Albert
• Primary Examiner(s): Arola, Dave W.
• Application Number:
  US08/495,003
• Time in Patent Office: 1,477 Days
• Field of Search: 285/21.2, 285/23, 219/544, 219/552, 219/553
• US Class Current: 285/21.2
• CPC Class Codes: B29C 65/00 Joining or sealing of preformed parts , e.g. welding of plastics materials; Apparatus therefor general aspects of processes or apparatus for joining preformed parts B29C66/00; using porous material formed by internal pressure generated therein for joining preformed parts B29C44/1228, B29C44/326
• CPC Class Codes: B29C 65/342 comprising at least a single wire, e.g. in the form of a winding
• CPC Class Codes: B29C 65/3468 characterised by the means for supplying heat to said heated elements which remain in the join, e.g. special electrical connectors of windings B29C65/3668 takes precedence
• CPC Class Codes: B29C 65/3476 being metallic
• CPC Class Codes: B29C 65/7841 Holding or clamping means for handling purposes clamping means for the purpose of applying pressure on the parts to be joined, in the area to be joined B29C66/81; work holders in general B25B; devices for holding or positioning work for welding metal B23K37/04
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/1142 Single butt to butt joints
• CPC Class Codes: B29C 66/3472 in the plane of the joint, e.g. along the joint line in the plane of the joint or perpendicular to the joint line in the plane of the joint
• CPC Class Codes: B29C 66/5221 for forming coaxial connections, i.e. the tubular articles to be joined forming a zero angle relative to each other
• CPC Class Codes: B29C 66/5229 involving the use of a socket
• CPC Class Codes: B29C 66/634 using an inflatable core
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/91651 by controlling or regulating the heat generated by Joule heating or induction heating
• CPC Class Codes: B29C 66/91653 by controlling or regulating the voltage, i.e. the electric potential difference or electric tension
• CPC Class Codes: B29C 66/91655 by controlling or regulating the current intensity
• CPC Class Codes: B29C 66/9241 by controlling or regulating the pressure, the force or the mechanical power
• CPC Class Codes: B29C 66/929 characterized by specific pressure, force, mechanical power or displacement values or ranges
• CPC Class Codes: B29C 66/94 by measuring or controlling the time
• CPC Class Codes: B29C 66/9672 involving special data inputs, e.g. involving barcodes, RFID tags
• CPC Class Codes: B29K 2023/06 PE, i.e. polyethylene
• CPC Class Codes: B29K 2023/12 : PP, i.e. polypropylene
• CPC Class Codes: B29K 2027/06 : PVC, i.e. polyvinylchloride
• CPC Class Codes: B29K 2027/12 : containing fluorine
• CPC Class Codes: B29K 2027/16 : PVDF, i.e. polyvinylidene fluoride
• CPC Class Codes: B29K 2071/00 : Use of polyethers , e.g. PEEK, i.e. polyether-etherketone or PEK, i.e. polyetherketone or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2081/04 : Polysulfides, e.g. PPS, i.e. polyphenylene sulfide or derivatives thereof
• CPC Class Codes: F16L 47/03 : Welded joints with an electrical resistance incorporated in the joint

Abstract

A process for fusion jointing or joining of pipe sections includes the steps of covering planed ends of the pipe pieces with an electric socket. The electric socket has a heating device disposed therein, and a heating output of the socket is such that an effective butt-jointing occurs between the pipe pieces. A bellows can be placed within the pipes to prevent collapse thereof, and to improve an inner bead quality of the pipe parts.

Claims

1. A socket for fusion-jointing of plastic pipe parts, said socket comprising:

a housing having two ends, an outer surface and inner surface;

an electric heating element disposed in said housing adjacent the inner surface thereof, said heating element being configured to provide a higher heating output at a center region thereof between the two ends, adjacent a joint to be fused, than at outer regions thereof toward the two ends and disposed away from the joint to be fused.

2. A socket as recited in claim 1, wherein said electric heating element comprises a heating coil, said heating coil having a winding spacing which is smaller in the center region adjacent the butt joint to be fused than at the outer regions thereof.

3. A socket as recited in claim 1, wherein said electric heating element comprises a heating grid formed of a wire mesh, with wires of the mesh which are radially disposed with respect to pipe parts to be joined are closer together in the center region adjacent the joint to be fused than the outer regions thereof toward the two ends.

4. A socket as recited in claim 1 wherein the electric heating element comprises a coil having a constant pitch, wherein a diameter of heating wire forming the coil is thinner in the center region adjacent the joint to be fused than in outer regions thereof.

5. A socket according to claim 1, wherein said electric heating element comprises a first heating coil extending in an area between the two ends of the housing, with a second heating coil provided in the housing in the center region adjacent the joint to be fused.

6. A socket according to claim 1, wherein the housing has an axial length which is in a range of 0.2 to 1.00 times an inner diameter of one of the first and second pipe parts.

7. A socket according to claim 1, wherein the housing has an axial length which is approximately equal to an inner diameter of one of the first and second pipe parts.

8. A socket according to claim 1, wherein the housing has an axial length which is in a range of 0.4 to 0.6 times an inner diameter of one of the first and second pipe parts.

9. A socket according to claim 1, said socket further comprising holding means for holding the pipe parts to be fusion-jointed, said holding means being integrally attached to the at least two ends of the housing.

10. A socket according to claim 9, wherein said holding means comprises socket attachments attached to said two ends of the housing, said socket attachments having inner diameters which correspond to an inner diameter of the housing, said socket attachments having a wall thickness which is less than a wall thickness of the housing.

11. A socket as recited in claim 1, wherein said electric heating element is embedded within the socket housing.

12. A socket as recited in claim 1, wherein said electric heating element is disposed in the housing between the two ends thereof.