Plug release indicator
US4928520A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 7, 1989 |
| Grant date | May 29, 1990 |
| Priority date | — |
| Expiry date | Nov 7, 2009 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/092
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A plug release indicator is provided which includes an elastomeric probe, with a wire embedded therein, which extends into the interior area of a plug housing or well casing. The wire has a lip at one end and an anchor at the other end, such that when a cementing plug contacts and deflects the probe, the lip moves thereby closing a micro-switch. The micro-switch closes an electrical indicating circuit including a power supply, indicator light, buzzer, or the like. In a second embodiment, a wire contacts the cementing plug and rotates a shaft containing a magnet therein. The magnet then activates a magnetic switch thereby closing the electrical indicating circuit. Another embodiment includes an electrically conductive surface embedded within an electrically insulating rotatable shaft. Upon rotation of the shaft, the conducting surface completes an electrical circiut through adjacent electrical contacts and the electrical indicating circuit is closed. Thus, the present invention indicates the precise instant when a cementing plug is released, or passes by the plug release indicator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.