GB400719A - Improvements in apparatus for the electrostatic deposition of particles suspended ingases - Google Patents

Abstract

In electrical precipitation apparatus, the lead-in insulator for the high tension supply to the discharge electrode system is situated in an extension of the main precipitation chamber and a shield is arranged on the high tension conductor to cause condensation of matter in the gases to be treated before they come into contact with the insulator. In the arrangement shown in Fig. 1, the insulator 7 is arranged at the top of an extension chamber 10 communicating with the treater through a narrow passage 9. A shield 11 is electrically connected to the high tension conductor 6 with a gas-tight seal and forms a narrow passage 12 through which any gases must pass before reaching the insulator 7, thereby being cooled <PICT:0400719/III/1> partition in a cup 18 carried by the high tension conductor 6. This cup collects condensed matter from the insulator chamber and allows excess to drain away and also forms a liquid seal to prevent gas which has not passed through space 15 reaching the insulator. To assist precipitation in the space 15, stabbed metal sheets 27 may be placed on one or both interior walls of this space. The neck 9 of the treater extends within the shield 14 to form a liquid seal for use when the treater is inoperative, so that fog, due to the absence of precipitation, will not condense on the insulator. The sealing liquid, such as oil, may be supplied from the bottom of a container 20 by valved pipe 21. The upper part of the container may be placed into communication with the treater 1 or the atmosphere by means of a two-way cock 22. When the container and treater are in communication, the pressures therein are equalized and the liquid flows into the chamber 13 on opening the valve in pipe 21. To empty the seal, the container is placed into communication with the atmosphere, when the liquid is by contact with the outer walls of the chamber 10. The shield also forms an electrostatic shield for the insulator. In the construction shown in Fig. 2, the cylindrical shield 14 forming with the chamber 13 the narrow cooling space 15 has a partition 16 which forms the base of the insulator chamber. The shield is supported by a cylindrical extension 17 of the <PICT:0400719/III/2> <PICT:0400719/III/3> forced back into the container by the pressure of the gas in the treater. A needle valve, operated by float 25, in the end 26 prevents the liquid being forced out of the container. In the modification shown in Fig. 3, an earthed curved conical shield 28 and a heating coil 29 are provided round the upper end of the insulator. This shield enables the potential along the surface of the insulator to be evenly graded. The heating coil may be provided without the earthed shield and may be cylindrical in form.