US2313389A - Electrical precipitator - Google Patents

Description

March 9, 1343. F, sTo V 2,313,389

ELECTRICAL PRECIPITATOR Filed May 3, 1941 2 Sheets-Sheet 1- 3M fiWa-SW Mmh 9, 1943. A, F, MESTQN 2,313,389

' ELECTRICAL PRECIPITATOR I 2 Sheets-Sheet 2 Filed May 3, 1941 Patented Mar. 9, 1943 v amass ELECTRICAL PRECIPITATOR Archibald F. Meston, Bound BroolE, N. 3., assignor to Research Corporation, New York, N. Y., a corporation of New York- Application May 3, 1941, Serial No. 391,790

(Cl. its-'1) Claims.

This invention relates to an electrical precipitator and particularly to an electrical precipitator providing a succession of fields of high concentration alternating with fields of relatively low concentration, I

As was pointed out in my United States Patent No. 1,903,644, it is advantageous in the treatment of some gases and suspended materials by electrical precipitation to maintain a succession of zones of highly concentrated electric field in the treating apparatus. It was found, however, that such concentrated field zones were very sensitive to changes in the condition of the electrode surface upon which the concentrated field terminated, and it was found advantageous to provide complementary electrode systems wherein the highly concentrated field is established only to a minor portion of the collecting electrode surface and means is provided for continuously or substantially continuously cleaning this portion of the collecting electrode to prevent disruptive spark-overs between the electrodes.

It has now been found that the use of succesing electrode assembly embodying the principles of the invention:

Fig. 5 is a fragmentary front elevation in partial section of the auxiliary collecting electrodeassemblyof Fig. 4;

Fi 6 is a section on line 6-6 of. Fig. 4; and

Fig. 7 is a top view of the electrode assembly of Fig. 4. g

In the electrical precipitator shown in Figs. 1, 2 and 3, III is the precipitator shell provided at the ends with inlet and outlet gas passages Ii and I2, respectively.

The collecting surfaces of the precipitator comprise the side walls 01' the shell and the auxiliary collecting electrodes l3 associated therein spaced relation to the collecting surfaces and insulated therefrom by insulating bushings ll sive concentrated fields terminating on auxiliary collecting electrodes which are kept substantially free from deposited material is particularly advantageous for the cleaning of air or other gas with a minimum of ozone production, especially in combination with composite electrodes including both discharge-forming and non-discharge-forming portions. as described in my application Serial No. 391,789; filed herewith.

In order to provide substantially continuous operation of the precipitator with a minimum of interruptions and of periods of low 'efliciency operation, it has been found advantageous to pro- 1 vide for the removal and replacement of the portions of the collecting electrode surface upon -which the concentrated electric field terminates with little or no interruption in 'the operation of the precipitator, and it is one of the purposes of the present invention to provide an electrical precipitator including auxiliary electrodes upon which concentrated electric field may be causedto terminate and which may be readily removed from the precipitator and replaced therein.

Other purposes and advantages of the invention will appear from the following description.

The invention willbe more particularly. described with reference to the accompanying drawings in which:

Fig. 1 is a semi-diagrammatic elevation in partial section of an electrical precipitator embodying the principles of the invention:

Fig. 2 is a transverse section on line 2- of Fig. 1;

Fig. 3 is a plan view of the precipitator of Fig. 1;

Fig.4 is an enlarged fragmentary side elevation in partial section of an auxiliary collectwhich pass into insulator chambers IS. The insulator chambers are advantageously provided with flushing means which, in the. illustrated embodiment. comprise a supply conduit it for dry air or other inert gas, providing a slow but,

continuous gas current through fibrous material into the insulator chambers and thence into the precipitator chamber throughbus bar 7 wire discharge portions 20. I

The auxiliary collecting electrodes i3 are preferably positioned along the collecting electrode surface opposite each discharge electrode or the discharge portion thereof, and project. into the interelectrode space, so that an electric field of high concentration termihates thereon, while a field of substantially lower concentration terminates on the remaining portions of the collecting electrode surface. In order to maintain thev surface of the auxiliary collecting electrodes.

cleaning, wiping or scraping means are provided together with drive means for continuously or intermittently rotating the auxiliary electrodes against the wiping or scraping means.

Referring more particularly to Figs. 4-7, the

auxiliary collecting electrode assembly includes a channel-shaped mounting plate 2i, "bearing means. for supporting the rod-like auxiliary collecting electrodel3 for rotary motion about its longitudinal axis, and cleaning means. The bottom bearing is provided by upstanding pintle 22 carried by supporting plate 23 which is mounted, A

for example, by welding, on the lower end of channel member 2|. Supporting plate 23 is tapered at its lower end to facilitate insertion into stirrup 35 which is attached to the side wall of the shell. Mounted in channel member 2| is a channel-shaped backing member 24 carrying felt the hole in the top of the precipitator case through which the auxiliary electrode assembly is inserted and removed, and is separated from the upper end of the main portion of electrode l3 by felt washer 21. The upper ends of channel member 2|, backing plate 2-! and wiper pad 25 project into a slot in bushing plate 26and are fastened therein by means. of pin 28.

The electrodes l3 may be-rotated by any suitable drive mechanism, for example, by a belt 30 engaging pulleys 3i keyed or otherwise-attached to the extended upper portions l3 of the elec trodes, as shown in Fig. 3, wherein 32 is a motor, 33 a reducing gear, and 38 belt tensionin devices. This arrangement permits any of the auxiliary electrode assemblies to be removed from the precipitator for cleaning, repair or replacement without interrupting the operation of the precipitator.

To assemble the unit the backing plate 24, with felt 25 evenly packed into it, is first laid in the channel member 2i. The electrode I3 is then laidon the felt and its lower end is slipped over pintle 22 providing the bottom journal. Felt washer 21, followed by bushing plate 26, are next slipped over bearing portion [3' or the electrode, the upper ends of plate 24 and channel member 2| being guided itno the slot in bushing plate 26. When the holes in plate 24,, member 2! and plate 26 are lined up, holding pin 28 is inserted. Suitable pulleys or gears are now attached to the upper end of the journal l3. The assembly is now complete and may be inserted into the precipitator as a unit.

It will be obvious that the form and arrangement of the precipitator and its constituent parts shown by way of example in the drawings are merely illustrative of the principles of the invention and are subject to wide variation within the scope of the invention as defined in the claims.

Additional precipitator sections maybe included within shell l0. Such additional sections may be similar to the section illustrated in the drawings or they may be different either in the collecting electrode or the discharge electrode assemblies. An additional precipitator section may consist, for example, of conventional collecting and discharge electrodes, or of conventional discharge electrodes with the concentrated field collecting electrode assembly of the invention, or of composite discharge electrodes of the type illustrated in Fig. 1 associated with conventional collecting electrodes.

I claim: r

1. An electrical precipitator comprisirm a shell defining a precipitating chamber, extended collecting electrode surfaces provided at least in part by the walls of said shell, openings in said shell adjacent said extended collecting electrode surfaces, an auxiliary collecting electrode assembly adapted to be inserted into the precipitating chamber through said openings and comprising an elongated electrode member, a support member extending along said electrode member and supporting said electrode member for rotation about its longitudinal axis, and cleaning means carried by said support in contact with said electrode member throughout the length thereof, and a discharge electrode member positioned in said precipitating chamber and spaced more closely to an auxiliary collecting electrode member than to said extended collecting electrode surface.

2. An electrical precipitator comprising a shell defining a precipitating chamber, extended collecting electrode surfaces provided at least in part by the walls of said shell, openings in said shell adjacent said extended collecting electrode surfaces, an auxiliary collecting electrode assembly adapted to be inserted into the precipitatin chamber through said openings and comprisin an elongated electrode member, a support member extending along said electrode member and supporting said electrode member for rotation about its longitudinal axis, surface wipin means carried by said support in contact with said electrode member throughout the length thereof and means for rotating said auxiliary collecting electrode in contact with said wiping means, and a discharge electrode member positioned in said precipitating chamber and spaced more closely to an auxiliary collecting electrode member than to said extended collecting electrode surface.

3. In an electrical precipitator, an auxiliary collecting electrode assembly comprising an elongated. electrode member, a'support member extending along said electrode member and supporting said electrode member for rotation about its longitudinal axis, and'surface wiping means carried by said support in contact with said electrode member throughout the length thereof.

4. 'An electrical precipitator comprising complementary discharge and collecting electrode systems, said collecting electrode system including an extended collecting surface, an auxiliary collecting electrode member projecting into the interelectrode space and means for maintaining the auxiliary collecting electrode substantially free from deposited material, said discharge electrode system comprising a nondischarge portion and a discharge portion mounted on the non-discharge portion in a position closer to said auxiliary collecting electrode than to the extended collecting surface.

5. An electrical precipltator comprising complementary discharge and collecting electrode systems, said collecting electrode system including an extended collecting surface, an auxiliary collecting electrode member projecting into the interelectrode space and means for maintainin the auxiliary collecting electrode substantially free from deposited material, said discharge electrode system comprising a, non-discharge portion and a fine wire discharge portion mounted on the non-discharge portion in a position closer to said auxiliary collecting electrode than to the extended collecting surface.

ARCHIBALD F. MESTON.

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