US2903089A

US2903089A - Electric precipitator

Info

Publication number: US2903089A
Application number: US749483A
Authority: US
Inventors: Jr Burton F Latham
Original assignee: Continental Carbon Co
Current assignee: Continental Carbon Co
Priority date: 1958-07-18
Filing date: 1958-07-18
Publication date: 1959-09-08
Anticipated expiration: 1976-09-08

Description

Sept- 8, 1959 B. F. LATHAM, .1R

ELECTRIC PRECIPITATOR 3 Sheets-Sheet l Filed July 18, 1958 I NVEN TOR fgraf j? 917ml? ATTORNEY Sept. 8, 19.59 B. F. LATHAM, JR 2,903,089

ELECTRIC PRECIPITATOR Filed July 18, 1958 3 Sheets-Sheet 2 ATTORNEY Sept. 8, 1959 B. F. LATHAM, JR 2,903,089

ELECTRIC PRECIPITATOR Filed July 18, 1958 3 Sheets-Sheet 3 6,45 oar BY @ya ATTORNEY United States Patent O 2,903,089 i ELECTRIC PRECIPI'rAroR Burton F. Latham, Jr., Amarillo, Tex., assignor to Conytmental Carbon Company, Amarillo, Tex., a corporation of Delaware Application July 1s, 195s, serial No. 149,483

s claims. (c1. iss- 1) This invention relates to electric precipitators wherein aerosols are removed from a gas stream.

Ordinarily, the line fume or dust suspension in a gas stream can -be easily removed by passing the aerosol between the oppositely charged electrodes of an electrostatic precipitator. Electrons leaving the negatively charged electrodes (which are usually wires called high tension discharge electrodes) pass through the gas in the form of a corona discharge (migration of gaseous ions) to the positively chargedgrounded collecting electrode (which is usually a at plate or a tube). From the corona discharge, the aerosol particles pick up electrons and themselves become negatively charged. These negatively charged aerosol particles then migrate to the positively charged collecting electrodes where they are deposited. The collected particles adhere to the collecting electrodes and are discharged, periodically, or continuously, into hoppers with the aid of vibrating or rapping mechanisms.

. In the case of aerosols made up of light, fluffy materials which are highly conductive, such as carbon black, the particles rapidly lose their charge when they strike the collecting electrode and are then blown loose by the gas stream in the form of larger agglomerate particles. The agglomerate particles usually have a large enough mass to be separated by centrifugal force in cyclone collectors following the precipitator.

According to the teachings of the present invention, aerosols are removed from a gas stream by subjecting the suspended particles to simultaneous electrostatic and centrifugal forces. The apparatus employed comprises centriflow collecting electrodes which cause the aerosol passing between them to be subjected to a whirling motion and many changes of direction which tend to separate the suspended particles by centrifugal force and impingement, high tension discharge electrodes being centered between the curved surfaces of the centnow collecting electrodes to cause the suspended particles to become charged and to be separated by electrostatic separation.

The invention, then, comprises the features hereinafter fully described and as particularly pointed out in the claims, the following description and the annexed drawings setting -forth in detail certain illustrative embodiments of the invention, these being indicative of some of several ways in which the principles of the invention may be employed.

In said drawings:

Figure l is a fragmentary plan illustrating a form of apparatus which embodies the teachings of the present invention, the view having been broken away at the center thereof in order to eliminate unnecessary repetition;

Figure 2 is a fragmentary vertical sectional view illustrating more clearly the high tension discharge electrodes and the manner in which they are supported with respect to the collecting electrodes;

Figure 3 is a fragmentary perspective illustrating the bottom of the electric precipitator; and

r l j 2,903,089 Patented Sept. 8, 195,9

' found that sections formed of sheet steel which is 1A;

inch in thickness, 32.6 inches Wide and l2 feet longV work quite satisfactorily in the washing of gas ladened with carbon black, with the flat central portion approximately l0 inches wide and the curved portions 4 being pitched on a 5-inch radius and extending approximately 11.3 inches to provide an arc which is subtended by an angle of approximately 127 As shown in Figure l, eight vertically extending collecting elements or sections are assembled in two rows of four each, with the correspondingly adjacent curved portions of each row welded together, as at X, and with the two rows oppositely facing and in staggered relationship. This, of course, provides in each vertically extending collecting electrode element a pair of substantialll cylindrical vertically extending chambers; and the gas flowing at right angles therethrough is made to assume a curved or tortuous path, as shown at 7.

In the embodiment of Figure l, fifteen groups of oppositely facing and staggered sections 2 are employed, the same forming gas ducts which are designated A, B, C, N and 0, with the ten sections between sections C` and N omitted in the interests of eliminating unnecessary duplication. According to the dimensions set forth hereinbefore, the width of each of the ducts will be approximately l0 inches.

With the exceptions of the end rows of collecting electrode elements or sections, the ilat central portions of the sections abut and close the space between the curved portions 4 of the next adjacent and oppositely facing sections. The outside surfaces of the end rows of collecting electrode sections are provided with strips 10 which extend between the flat central portions of adjacent sections to close the spaces therebetween.

End baffles 14 are provided at each corner of the electric precipitator of the present invention, and also upper baffles 16, the apparatus being enclosed in a suitable shell or housing 18. The lower end of the housing comprises a hopper 22, the interior of which is provided with bales 24. This hopper 22 is wedge-shaped, as shown most clearly in Figure 3; and at the bottom thereof, there is disposed a screw-conveyor 26, one end of which communicates with a depending outlet duct 28, the latter having disposed therein a rotor wheel 30.

'Ihe high tension discharge electrodes of the apparatus of the present invention are generally indicated at 32, one being disposed at the approximate center of each of the substantially cylindrical vertically extending chambers which are dened by the cooperating curved portions 4 of the elements or sections 2 of the collecting electrodes. These high tension discharge electrodes 32 may acceptably be made from rods of one inch in diameter, with wires spirally wound around them.

The high tension discharge electrodes 32 are supported at their upper ends by a frame 36. Secured to the top of this frame 36 is a pair of parallel channels 38 which are, in turn, secured to a cross-member 40, the latter being attached to the lower end of an adjusting bar 42 which extends through the top of the housing.

With the curved portions 4 of the sections 2 of the collecting electrodes being pitched on a S-inch radius and extending overV arcs of approximately 127, it will be seen that the space between the ends of said curved portions and the inner surface of the fiat central portion 4 of the cooperating and oppositely facing sections 2 will ydefine a narrow slot or orifice of approximately 2 inches inA width. The gas to be cleaned must pass through the immediately aforementioned narrow slot or oriiice at a relatively high velocity to then strike the oppo-sitely-facing (i.e., downstream) curvedportion `4 of the centriiiow collecting electrodes which separates `the suspended particles by centrifugal force. This process is, according to the presently illustrated embodiment, repeated eight times in passing the full length of the duct between the collecting electrodes. The upstream curved portions 4 of the centriflow collecting electrodes form dead gas pockets wherein the suspended material can beV collected without being disturbed by the gas stream.

While I have sho-wn and described certain specific embodiments of the present invention, it will be readily understood that I do not wish to be limited exactly thereto, since various modifications may be made without departing from the scope of the invention as defined in the appended claims.

I claim:

1. In an electric precipitator, a housing containing a plurality of parallel and horizontally extending gas ducts, each of said gas ducts being defined by two oppositely facing rows of vertically extending electrode elements in closely adjacent side-by-side relationship, each of said vertically extending electrode elements including a substantially Iflat central portion with an inwardly curved portion at each longitudinal edge thereof, said rows of vertically extending electrode elements being staggered with respect to each other and with the inwardly curved portions being internested to provide in each element a pair of substantially cylindrical vertically extending charnbers, and a vertically extending high tension discharge electrode disposed centrally of each of said aforementioned chambers.

2. In an electric precipitator, a housing containing a plurality of parallel and horizontally extending gas ducts,

- 4 each of said gas ducts being deiined by two oppositely facing rows of vertically extending electrode elements in closely adjacent side-by-side relationship, each of said vertically extending electrode elements including a substantially at central portion with an inwardly curved portion at each longitudinal edge thereof, said rows of vertically extending electrode elements being staggered with respect to each other and with the inwardly curved portions being internested to provide in each element a pair of substantially cylindrical vertically extending chambers, and a vertically extending high tension discharge electrode disposed centrally of each of said aforementioned chambers, the arcs defined by the inwardly curved portions of said vertically extending electrode elements being subtended by .an angle of more than 3. In an electric precipitator, a housing containing a plurality of parallel and horizontally extending gas ducts, each of said gas ducts being defined by two oppositely facing rows of vertically extending electrode elements in closely adjacent side-byside relationship, each of said vertically extending electrode elements including a substantially flat central portion with an inwardly curved portion at each longitudinal edge thereof, said rows of vertically extending electrode elements being staggered with respect to each other and with the inwardly curved portions being internested to provide in each element a pair of substantially cylindrical vertically extending chambers, and a vertically extending high tension discharge electrode disposed centrally of each of said aforementioned chambers, the arcs dened by the inwardly curved portions of Said vertically extending electrode elements being subtended by an angle of approximately 127.

References Cited in the le of this patent UNITED STATES PATENTS 1,956,591 Gies May 1, 1934 FOREIGN PATENTS 374,833 Germany Apr. 28, 1923