Automatic control system for electric precipitators
US4152124A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 27, 1978 |
| Grant date | May 1, 1979 |
| Priority date | — |
| Expiry date | Mar 27, 1998 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB03C3/68
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
In an adaptive type of control for precipitators, the current reference ramp signal is compared with a precipitator current signal to produce a phase reference signal which is combined with sawtooth waves to produce a first train of pulses. In a spark detector, signals proportional to electrode potential are differentiated, and the differentiated output is integrated. The integrator output, if in excess of a reference potential, triggers a spark pulse of predetermined width and amplitude. The spark pulse, in addition to causing a predetermined small set back of the ramp signal, is integrated to produce a turn-off and recovery signal having a rapid excursion and subsequent slower return excursion of adjustable slope. The latter signal is combined with the sawtooth waves to produce a second train of pulses commencing after a predetermined turn-off interval and increasing in width at a predetermined recovery rate. Both trains of pulses are added to produce enabling signals for controlling the SCR's in the precipitator input circuit. Arc signals produced by an arc detector cause additional downward ramping of the ramp signal to minimize electrode current during arcing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.