Method and apparatus for calibration of electronic delay detonation circuits
US4986183A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 24, 1989 |
| Grant date | Jan 22, 1991 |
| Priority date | — |
| Expiry date | Oct 24, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/2631
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In the field of blasting, it is often desirable to ignite explosives at various relative times. Such delayed ignition can have advantages in better break up of rock and reduced ground vibration. A principle problem in using the time delay technique is the accuracy rate of a local oscillator which measures the delay time for each of the delay circuits. In the described system, a calibration interval, independent of any delay time, is transmitted from a control unit concurrently to each of the delay circuits wherein each delay circuit counts the output of its local oscillator during the calibration interval. This local oscillator output is then compared to a predetermined reference count, either at the delay circuit or at the control unit, and a correction factor is established. This correction factor is then applied to a delay count for the individual delay circuit. The delay count is modified to produce a corrected delay count that is utilized individually within the delay circuits to count the output of the corresponding local oscillator for determining the delay time until ignition. This technique utilizes the precise oscillator at the control unit to substantially eliminate the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.