Method of locating an electrical conductor between a first extruded tube and an extruded lining
US4929408A · kind A · utility
Inventors
Key dates
| Filing date | Apr 14, 1989 |
| Grant date | May 29, 1990 |
| Priority date | — |
| Expiry date | Apr 14, 2009 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C48/09
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Electroweldable pipe sockets and fittings by forming a first tube being internally sized and cooled and on the outer side provided with a groove, having preferably a raised edge part, winding an electrical conductor in the groove, and the outer side of the first tube with electrical conductor is coated with plastics thereby maintaining the internal size of the first tube by internal cooling and sizing. In this continuous process the speeds of the first tube and of the continuous tube leaving the coating extrusion stage are equal. In the coating extrusion stage a negative pressure is maintained between the first tube and the coating to be applied.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.