| 摘要 |
A method of controlling the pulse frequency of an electrostatic precipitator energized by a pulse superimposed direct voltage, is disclosed in which, for a given direct and/or pulse voltage, the pulse repetition frequency, at intervals which are preset or determined by one or more precipitator or operational parameters, is lowered and then increased stepwise according to a predetermined scale. At each value of the pulse repetition frequency the average current being measured and the transmitted charge per pulse (defined as the average current divided by the pulse repetition frequency) calculated. The stepwise increase of the pulse frequency is stopped when either the transmitted charge per pulse for a given direct and pulse voltage maintained in two successive frequency steps remains constant or increases or, where the charge per pulse is kept constant by regulating the direct and/or pulse voltage, when the numerical value of the controlled voltage in the last one or two successive frequency steps remains constant or drops. The limiting pulse repetition frequency is controlled to assume the frequency in the step where the stepwise frequency increase is stopped, until the next search procedure. |
