GB764936A - Improvements in or relating to rapping devices for electro-static precipitators - Google Patents

Abstract

764,936. Electrostatic precipitation. RESEARCH CORPORATION. Feb. 4, 1955 [Feb. 10, 1954], No..3352/55. Class 39(1). A rapping device for an electrostatic precipitator having an anvil face on an electrode structure comprises a hammer member, means for supporting said hammer member in the manner of a pendulum, and a nozzle arranged to direct fluid under pressure against said hammer member to impel it through an arc to strike said anvil face. The precipitator shown comprises collecting electrodes 14<1> and discharge electrodes 14 supported from a tubular frame member 11 suspended in a casing 10 by rods 13 depending from insulators 12. The end of the frame member 11 is formed with a thickened wall portion 15 inclined at an angle to provide an anvil face 16. The rapping device comprises a ball 17 suspended by a link 19 of rectangular crosssection from a support 18 located in an opening 20 through which the assembly can be withdrawn for replacement without shutting down the precipitator. A control valve 26 operated by a timer 22<1> supplies fiuid such as air or steam under pressure through a conduit 22 to a nozzle 23 carrying a cup 24 to impel the ball 17 upwardly along an arcuate path to strike the anvil face 16. A conduit 27 by-passing the main control valve 26 is provided with an auxiliary control valve 28 operated by a timer 28<1> to supply fluid during the return movement of the ball 17 under the influence of gravity to secure a cushioning action when the ball seats in the cup 24 under the guidance of spaced fingers 25 provided on opposite sides of the cup. In a modified construction the cup 24 is omitted and the nozzle 23 enters a recess provided in the ball 17. The device may be used for rapping the collecting electrodes of a precipitator if the support member 18 is made of insulating material.