Cleaning of high-voltage electrodes in an electrostatic precipitator

An impact rapper for vibrating an electrode support frame of an electrostatic precipitator, said support frame being charged with a high voltage, said rapper comprising:

• an elongate tubular high-voltage insulator, a rapper housing, means vertically mounting the proximal end of said insulator at its outer surface in said housing such that the distal end of said insulator extends downwardly a substantial distance below the bottom of said housing and is spaced above the electrode frame, an electrically conductive elongate rapper member having a cylindrical armature portion at one end thereof of a diameter that is smaller than the diameter of the bore of said insulator, said armature portion being freely vertically movable in the bore of said insulator, means attached to the extremity of said distal end of said insulator for guiding and spacing the rapper member along a vertical path of movement upwardly and downwardly within the bore of said insulator and being electrically isolated from said housing by said insulator, and solenoid means surrounding the proximal end of said insulator for cooperating with said armature portion of said rapper member and periodically causing said rapper member to be lifted upon energization thereof and dropped onto the electrode support frame thereafter upon de-energization thereof to thereby vibrate the electrode support frame, whereby when said rapper member is electrically charged by the electrode support frame, the insulator insulates the rapper housing from the rapper member to prevent grounding of the electrode support frame, and whereby when said rapper member is caused to move, said means for guiding and spacing prevents said rapper member from rubbing the inner surface of said insulator.