Fault detecting device for welded pipe joints
US4795877A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Sep 10, 1986 |
| Grant date | Jan 3, 1989 |
| Priority date | — |
| Expiry date | Sep 10, 2006 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C66/9592
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In an electron-fushion welding process a fault, e.g. due to incorrect assembly of the pipe joint components, is detected by sensing the welding current and emitting a signal to actuate an audible or visible alarm and/or to interrupt the welding process, if the welding current increases unexpectedly. A reference signal dependent upon the current dependent signal produced by the sensor and RMS to DC converter at a time t.sub.1 is held by a converter and is compared by a comparator with the current dependent signal transmitted through converter at subsequent intervals. So that the device does not react to transient current increase a delay arrangement delays the output signal for a given time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.