US2615530A - Liquid cleaned precipitator - Google Patents

Description

Oct. 28, `P HODSQN ErAL LIQUID CLEANED PRECIPITATOR Filed Nov. 25, 1949 2 COOL/N6 WA 7E@ OUTLET lllll mlllll INVENTORS 10e/er Hoa/.son

ATTOP/VE Y Patented Oct. 28, 1952 vum"DEDA STATES PATEN ori-ICE LIQUID CLEANED BRECIIITATOR fPeterHodson, Wellsville, N. Y., and Hans Klem- .;.perer, Belmont, Mass., assignors :to .The Preheater Corporation, New York., Y. AppucatmnNovember 25, 1949,"summer-1293641 .particles'of dust and thelike 'carried therein with subsequent deposit of the dustrinthese gaseson collecting surfaces. In particular, lthe invention contemplates cooling parts of the precipitator apparatus-so that advantage may also be taken of the' thermalhead existing between the hot; gases and cooler collecting surfaceto cause the particles tobeattracted thereto.

The invention will best be understood upon consideration of the following detailed description of an illustrative embodiment thereof when read in conjunction with the accompanying drawings in which:

Figure l is a sectional elevational view of one of a number of ionizing and collecting tubes employed in an electrical precipitator embodying the present invention.

Figure 2 is an enlarged View of a portion of Fig. 1 illustrating in detail a collecting trough for carrying 01T moisture precipitated from the gases together with particles washed from the collecting tubes, and

Figure 3 is a fragmentary view also on an enlarged scale of an alternative device for wetting the collecting surfaces.

In the drawings, there is shown one of a plurality of ionizing and collecting tube units that make up a complete electrical precipitator. The inlet conduit I through which the dust-laden gases flow downwardly in the direction of the arrow as indicated in the drawing is axially alined with the tube I2 that forms the gas passage of the ionizing section I4 of the precipitator and containing an ionizing wire I6. The collecting section I8 includes a similar tube 28 and the collecting electrode 22. The ionizing and collecting electrodes I6, 22 extending axially of the tubes I2, 20 are supported in suspended relation therein between the support rods 24 and 26 which are supported at their ends in the insulators 28 and connected to the high voltage'leads 29. The insulators 28 are located at the outer ends of the neck-like extensions 30 of the tube I0 with which are 'associated heating coils 32 which serve to maintain the insulators and adjacent part of the ionizing tube and its electrode in a dry state.

The charging of particles in the ionizing section is accomplished veryrrapidly, in the matter of a 'particleszto-be removed.

' The exact proportionsfoftheapparatus'will, of

course, `'diier -with-` circumstances 'o'f gas quantity andvelocity 1 and i the nature fand density of the Above the location 'of the `ionizing -wire l I6 -several-steam nozzles l'3 3l introduce'-moisture into the Vstreamof gas immediately-'adjacent the'en- `trance tothe ionizing section I4. Surrounding the relatively narrowed tube portions I2 and 20 of the ionizing and collecting sections are water jackets 36 formed between these tubes and casngs 38 to be supplied through the inlet pipes 40 with the cooling water being drawn off through the outlet pipe 42. The cooling of the walls of the ionizing tubes I2 causes some of the steam and condensable constituents of vapor in the gas to condense on the inner wall 44 of the narrow tube section. This condensed moisture together with any dust particles which m-ay be driven to the wall because of the thermal head existing between the relatively hot stream of gas and the relatively cooler wall 44 runs down the latter in a thin lm and drips off the dared portion 46 at its bottom into collecting trough 48 of annular form that is mounted beneath the tubes I2 and inclined transversely with respect to the axis of the tube so that the water collected in the trough may flow downwardly to the drainage tube 50.

more dust carried off. The quantity of steam admitted through the jets 33 and the rate of flow of cooling water through the jackets 36 may be regulated to give any desired thickness of water lm. The particles of water in the gas condensed on the dust particles act on nuclei and these l particles of water tend to go to a cool surface such as the Walls 44 of the tubes I6 and 20 thus materially aiding collection. The dust particles stick to the cool wet surface until Washed off and 'I'he same action takes place in the collector section I 8 with a greater quantity of water being condensed and tubes also drives the particles towards the wall 44 thereof and water being a dipole lends itself readily to electrostatic precipitation. Even uncharged particles of water tend to move to the center electrode 22 in the collector section I8 because of the fact that they are dipoles and this assists in keeping the center electrode clean. The employment of water' also causes a solid or liquid compound to be formed with gases such as gases SO2 and NO2 which otherwise would not be collected. The electron attachment for water vapor slows down the ion mobility reducing the current required and increasing the breakdown field strength` v Y .f I

Figure 3 shows the ionizing tube I2 formed with several orices 52 near its upper end so that water from the water jacket 36 may pass through the tube wall to now along its surface 44 to cool it and cleanse it of collected particles separated from the gas stream.

While a single tube two-stage collector has been illustrated, it will be appreciated that the same method may readily be applied to a single stage or multiple stage collector and obviously may be embodied in' apparatus employing a large number of multiple tube collectors.

What we claim is:

Apparatus forthe precipitation of electrically charged dust particles or the like from suspension ina gaseous carrier uid comprising; vertically disposed tubular members mounted in spaced relation and in axial alignment; means including wall elements forming a-chamber between said members in communication therewith and together with said members forming a continuous 4 gas passage; individual precipitator electrodes extending axially of said members; electrical means for charging said electrodes extending into said chamber for connection with said electrodes; insulators for said electrical connecting means in the walls of said chamber; means for introducing moisture into the stream of laden gases; means forming cooling jackets surroundingthe wall of each tubular member; means for continuously circulating a cooling medium through said jackets to condense nuid from the stream of gases upon the walls of said tubular members; annular uid collecting troughs extending transversely across the lower end of each tubular member and disposed opposite its lower perimetral edge for receiving the stream of iiuid and entrained particles owing from the inner wall of said tubular member; drain means connected to said troughs for carrying away the liquid collected therein; and heating means associated with said insulators for protecting them from moisture in gases owing through said chamber and maintaining them in adrystate. --i- 'L PETER HODSON. HANS KLEM'PERER.-

REFERENCES Crrnn' The following references are of record inthe file of this patent: i

UNITED STATES PATENTS McGee et al. June lll, 1921

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