US1981754A - Electrical precipitator - Google Patents

Description

7 Nov. 20, 1934. H. A. POILLON ELECTRICAL PRECIPITATOR I.

Filed July 29, 1932 2 Sheets-Sheet 1 Nov. 20, 1934. H. A. POILLON ELECTRICAL PREG IPITATOR Filed July 29, 1932 2 Sheets-Sheet 2 'CIIJ Patented Nov. 20, 1934 ELECTRICAL PRECIPITATOR Howard A. Poillon, New York, N. Y., assignor to Research Corporation, New York, N. Y., a cor- J poration of New York Application July 29, 1932, Serial No. 625,957

3 Claims.

This invention relates to an electrical precipitation system and particularly to a system of the type including a separation chamber having a plurality of discharge electrodes therein spaced from-collecting electrode surfaces, and wherein the gas to be treated is passed through the separation chamber in such manner that all of the particles suspended or entrained therein pass through at least one electric field of high intensity.

In the operation of electrical precipitators of the type wherein the separation chamber comprises a plurality of concentric annular compartments, each containing a plurality of longitudinally extending discharge electrodes arranged symmetrically about the axis of the chamber,

it has been found that precipitation of the sus-,

pended matter is not complete. Because of the particular shape of the space between the discharge electrodes and the compartment walls, the electric field is non-uniform in intensity, there being certain areas midway between adjoining discharge electrodes and extending throughout the length of the separation chamher compartments wherein the field intensity is so low that very little, if any, of the gas passing through these areas is ionized, hence much of the suspended matter is not precipitated.

The present invention is directed toward overcoming this objectionable feature of the concentric cylindertype of separation chamber. According to the present invention, the gas entering the separation chamber is given a spiral movement whereby every portion of the gas passes by at least several discharge electrodes and consequently passes through several areas of high field intensity.

One of the objects of the present invention is the provision of an electrical precipitation system wherein all of the gas passing through the precipitator passes through a portion of the electric field wherein the field intensity has a high value.

Anotherobject of the invention is the provi- 'sion in a precipitator of the type wherein the separation chamber is divided into a plurality of concentric annular compartments, of apparatus for causing all of the gas which is to be treated, to pass through an electric field of high intensity.

the following" description taken in connection with the accompanying drawings, wherein:

Fig. l is a view showing a vertical section taken through a precipitator constructedaccording to the invention,

Other objects of the invention will appear fromv through the cylindrical wall 3 and have their Figs. 2 and 3 are transverse sections taken along-lines II-II and III--III, respectively of Fig. 1,

Figs. 4 and 5 are fragmentary views showing details of construction, and

Fig. 6 is a field map of a portion of the field set up in the separation chamber of a precipitator of the type shown and described in the present application.

In the particular. embodiment illustrated in the drawings, the gas stream entering by the upper header 1 passes downwardly through the treater to the lower or outlet header. As best shownjn Fig. 1, the lower header includes a short vertical cylinder 3, merging into a depending conical portion 4 which is provided with a trap door 5 for removing collected material. The lower header is supported from the ground or a rigid base in any appropriate manner, for example by a plurality of pillars 6 to which the cylinder 3 is $8- cured.

A frame 7 extends across the bottom of the header and supports a cylinder 8, of small diameter, which extends above the header and axially of the treater. A plurality of frame members 9 have their inner ends secured to the central cylinder 8 and extend radially of the header to the cylindrical wall 3 at such points thereon that the supports 6 serve also as supports for the outer ends. of the frame member 9.

The outer wall of the treater chamber is formed by a cylinder 10 of somewhat less diameter than the cylindrical wall 3 of the lower header, the lower end of the cylinder 10 resting in notches formed in the frame members 9 and, in turn, serving as the support for the upper cylindrical housing 11. Between the outer cylinder 10 and the inner cylinder 8 are additional cylinders 12, 12 which cooperate therewith to divide the space within the treater into three concentric cylindrical compartments of annular cross-section, all of which are of substantially the same width.

Extending laterally from the cylindrical housing 11 are two chambers 13 for housing the insulators 14 that support the cross-members 15. Three concentric rings 16 are secured to the crossmember 15 to serve as the upper terminals of the three sets of wires.17 that extend through the concentric treater compartments as the discharge electrodes of the precipitator. The lower endsv of the discharge electrodes 17 are secured to the appropriate ring 18 of a set of three rings located in the lower header. The lower rings 18 aresecured to positioning members 19 that extend outer ends mounted on insulators 20in housings 21, the construction being similar to that employed for supporting the upper cross-member 15. A high tension lead 22 extends through one of the insulators and is adapted to be connected, in the usual manner, to an appropriate source of high voltage electric current.

As shown in Fig. 1, the majority of the discharge electrodes 17 hang vertically in the treater compartments, but this arrangement is not desirable for those electrodes which are adjacent the frame members 9. As shown in Figs. 4 and 5, the lower ends of the pairs of electrodes 17 which pass close to the members 9 are spread apart to increase the gap between the electrodes and the frame, thus minimizing the possibility of arcing between these members.

The upper header 1 overlies the cylindrical housing 11 and terminates in a cruciform head 23, each arm of the head having three nozzles 24 which are directed angularly towards the upper ends of the three concentric'treater compartments. The shape and arrangement of the nozzles 24 is such that the gas streams flowing through the concentric compartments partake of a circumferential as well as an axial movement as they pass through the treater.

The cleaned gases pass from the lower header by way of an outlet flue 25.

The'operation of the apparatus is as follows: The apparatus is connected to a source of high voltage electric current, as stated above, and an electric field is thereby set up in the various compartments of the separating chamber. The gas which is to be treated is introduced into the inlet chamber 11 through the four sets of nozzles 24, and due to the angular position of the nozzles, enters the upper ends of the compartments angularly and is deflected by the walls 8, 10 and 12, along a helical path through the compartment.

As will be seen from Fig. 6, the intensity of the electric field set up in the separating chamber is'not uniform as there are zones 26 located midway between the discharge electrodes and extending parallel thereto in which the electric field intensity is very low. If gas flows through the compartments in a direction parallel to the discharge electrodes, the portions of the .gas which flow through these zones of low field intensity are but slightly ionized and therefore very little suspended matter is precipitated. By causing the gas to travel in a helical path, all portions of the gas are made to flow past areas of high field intensity and a complete precipitation of all the suspended matter is assured.

As the deposited material builds up on the collector electrodes, it may fall into the hopper-like collecting chamber 4 or, if of an adherent nature, a suitable form of rapping system (not shown) may be employed to loosen the deposits.

It is obvious that various other means for accomplishing the how of gas past areas of high field intensity may be employed without departing from the spirit of the present invention, the apparatus shown and described herein being only an illustrative form. I therefore desire that the claims be given the broadest interpretation consistent with their wording and the prior art.

I claim:

1. In apparatus for the electrical precipitation of suspended matter from a gas, the combination with a chamber having a plurality of concentric compartments of substantially annular cross-section, of discharge electrodes extending axially through said compartments, and nozzles disposed adjacent one end of each of said compartments for causing the gas which is to be treated to'flow spirally through the respective compartments.

2. In an electrical precipitator, a lower housing comprising a cylindrical member, pillars secured to said member for mounting the same upon a base, frame members secured to said pillars and extending radially within said member, a plurality of concentric cylinders carried by said frame member, an upper housing supported by the outer of said cylinders, and discharge electrodes extending through the compartments formed by and between said cylinders.

3. In apparatus for the electrical precipitation of suspended particles from a gas stream comprising a chamber with a gas inlet and gas outlet, collecting electrode members positioned in said chamber to define concentric passages there-

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