Methods of and systems for controlling the expansion of cellular plastic insulation in the manufacture of insulated conductors
US4359436A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 29, 1981 |
| Grant date | Nov 16, 1982 |
| Priority date | — |
| Expiry date | Apr 29, 2001 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2948/92933
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A conductive element (22) is preheated by a preheat power supply (34) to an initial temperature which is a function of line speed. The preheated conductive element (22) is advanced through an extruder (32) whereat a cellular insulation layer (24) and a solid plastic insulation layer (26) are extruded thereabout to form an insulated conductor (20). The insulated conductor (20) is advanced through an air gap (38) whereat the cellular insulation layer 24 expands about the conductive element (22). The insulated conductor (20) is then quenched at a point to stop the expansion of the cellular insulation layer by passing the insulated conductor into a cooling bath (40). A capacitance monitor (50) measures the coaxial capacitance of the insulated conductor (20) and develops an error signal. Thereafter, a microcomputer (54) facilitates the adjustment of the temperature of conductive element (22) as a function of line speed and the error signal and the adjustment of the point of quenching as a function of the error signal. The adjustment of the temperature and the point of quenching facilitates control of the expansion of the cellular insulation layer (24).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.