Electrostatic precipitator electrode cleaning system

In an electrostatic precipitator having electrically-activated rappers arranged in a plurality of modules that operably extend transverse to the gas flow direction through the electro-static precipitator, each of said modules comprising a plurality of rappers connected in parallel across associated busses, and each of said rappers having an electrically-operated normally-open switch connected thereto to control the flow of electricity to the rapper from the associated buss;

• and each of said rappers being connected to shake an electrode of the precipitator to dislodge particulates therefrom, a system for operating the rappers the improvement comprising:
• a. a main distributor circuit including a plurality of output lines, said main distributor circuit operating to place an electrical signal on each one of said output lines in sequence and to the exclusion of the other said output lines at a first predetermined rate;
• b. a plurality of control circuits, each said control circuit associated with a particular one of said modules and each said control circuit including:
• i. a timer means for generating a continuous train of signals at an adjustable second rate that is substantially slower than said first predetermined rate;
• ii. synchronizing means connected to a particular one of said output lines of said main distributor circuit to receive signals therefrom and, also, connected to receive said train of signals from said timer means, said synchronizing means being operative to generate an output signal only if it receives a signal from said timer means followed by a signal from said main distributor circuit;
• and
• iii. a secondary distributor circuit that is connected to receive said output signals from said synchronizing means and which includes a plurality of output lines, each of said secondary distributor output lines being connected to a said switch of a particular one of said rappers in the associated module, said secondary distributor circuit being operative to place an electrical output signal on each of its said output lines in an ordered sequence and to the exclusion of the other of its said output lines, each sequential placement being made upon the receipt of an output signal from said synchronizing means, and said electrical output signals from said secondary distributor circuit being operative to close the switch of the rapper which receives the signal to activate that rapper with power from said associated buss.