US3201923A

US3201923A - Device for cleaning the collecting electrodes in electrostatic precipitators

Info

Publication number: US3201923A
Application number: US63874A
Authority: US
Inventors: Gustafsson Stig; Mildh Gosta
Original assignee: Svenska Flaktfabriken AB
Current assignee: Svenska Flaktfabriken AB
Priority date: 1960-01-30
Filing date: 1960-10-20
Publication date: 1965-08-24
Anticipated expiration: 1982-08-24
Also published as: BE596864A

Description

Aug. 4, 1965 s. GUSTAFSSON ETAL 3,201,923

DEVICE FOR CLEANING THE COLLECTING ELECTRODES IN ELECTROSTATIC PRECIPITATORS 2 Sheets-Sheet 1 Filed Oct. 20, 1960 4, 1965 s. GUSTAFSSON ETAL 3,201,923

DEVICE FOR CLEANING THE COLLECTING ELECTRODES IN ELECTROSTATIC PRECIPITATORS 2 Sheets-Sheet 2 Filed Oct. 20, 1960 United States Patent 3,201,923 DEVICE FOR CLEANING THE CQLLECT- ING ELECTRODES IN ELECTROSTATIC PRECIPITATORS Stig Gnstafsson, Jonkoping, and Glista Mildh, Vattersnas,

Sweden, assignors to Aktiebolaget 'Svenska Flaktfabriken, Nacka, Sweden Filed Oct. 20, 1960, Ser. No. 63,874 Claims priority, application Sweden, Jan. 30, 1960, 935/60 2 Claims. (Cl. 55-112) The present invention relates to a device for cleaning electrostatic precipitators in which the collecting electrodes are in the form of a plurality of side-by-side rows of preferably plate-shaped electrode elements parallel to the direction of gas flow. The electrode elements in each row are pivotally suspended in tandem relationship. The device includes impact bars disposed beneath the electrodes and carried by the same, and which are arranged to be actuated by hammers mounted on a rotatable shaft extending transversely to the direction of gas flow to thereby impart to the electrode elements an oscillatory movement in the direction of the gas flow.

In prior art arrangements of the kind referred to, upstanding U-shaped guide brackets have been mounted on laterally-extending rails rigidly secured at their opposite ends to the walls of the electrofilter to provide guiding units for guiding the impact bars against lateral movement. However, due to the difference in heating of the guiding units on one hand, and the filter casing on the other, a diiference in thermal expansion has occurred which has caused bending or displacement of the guiding units. Therefore, in conjunction with mounting the guide rails in the walls, it has been necessary to dispose the rails so as to provide ample clearance between the bottom edge of the impact bars and the top edge of the guide rails to thereby alford sufficient freedom for thermal expansion of the collecting electrodes. Because of this, it has been necessary to make the upright legs of the guide brackets unreasonably long whereby the voltage gaps between the legs and the emission frame became critical and whereby the breaking stress at the anchor points between the brackets and the rails caused reduction of the mechanical strength. Sometimes when the clearance between the bottom edge of the impact bars and the top edge of the guide rails was too small,

the expansion of the collecting electrodes has caused their upper ends to become disconnected from their suspension mountings, resulting in a complete breakdown or collapse of the precipitator.

It is an object of the present invention to eliminate these drawbacks. To this end, in accordance with the present invention, the impact bars are guided against lateral movement by U-shaped guide brackets mounted on laterally-extending rails which are disposed at the ends of the electrode rows and are secured to, and carried by, the two outermost impact bars.

Another important feature of the present invention is the provision of baffle plates depending from the laterally-extending rails to prevent any substantial amount of gas from flowing longitudinally in the space beneath the electrodes.

The invention will now be described in greater detail with reference to the accompanying drawings in which:

FIG. 1 is a fragmentary longitudinal vertical section with portions broken away through an electrostatic precipitator embodying a cleaning device in accordance with the present invention;

FIG. 2 is a fragmentary transverse vertical section with portions broken away taken along the line 2-2 of FIG. 1;

3,201,923 Patented Aug. 24, 1965 FIG. 3 is a fragmentary perspective view showing two impact bars and their associated collecting electrodes (one being removed) and the intermediate emission electrodes; and

FIG. 4 is a view in side elevation with portions broken away of an electrostatic precipitator embodying the present invention.

Referring now to the drawings, the electrostatic precipitator 1 comprises a casing 2 having an inlet 2a and and outlet 2b. Within the casing are a plurality of plate-shaped collecting electrodes 3 arranged parallel to the direction of gas flow in a series of transversely-shaped longitudinal rows As shown in FIG. 4, the electrodes 3 are mounted for swinging movement as indicated at 3a in a suspension mounting 3b adjacent the top wall of the casing 2. Intermediate the adjacent rows of collecting electrodes 3 are longitudinal rows of discharge electrodes 16, in the present instance in the form of rods (see FIGS. 2 and 3).

For cleaning the electrodes, the electrostatic precipitator includes a cleaning device which consists of a number of impact bars 4 arranged to be engaged by hammers 6 mounted on a rotary shaft 5 extending transversely across the casing. In the present instance, the shaft 5 is mounted in journals 5a supported on standards 5b projecting inwardly from the wall of the casing 2. As shown in FIG. 2, the shaft 5 is rotated by a sprocket 14 adapted to receive a chain from a drive' motor (not shown). The hammers 6, upon rotation of the shaft 5, swing against the impact bars 4 substantially as shown in US. Patent No. 2,864,459 to Gustafsson. The impact bars 4 are provided with a plurality of studs 7 along their length adapted to engage against lugs 25 depending from the electrodes 3. There is an impact bar for each longitudinal row of collecting electrodes 3 and it is carried by the outermost electrodes in each row by means of supporting pins 9 projecting laterally from the lugs 8a of the outermost electrodes. As shown in FIGS. 1 and 3, the supporting pins 9 underlie the impact bars 4 to provide the sole vertical support therefor.

In accordance with the invention, the impact bars 4 and the electrodes 3, are guided against lateral movement by U-shaped guide brackets 10 which in the present instance, comprise a pair of upstanding legs 10a mounted on laterally-extending tubular rails 11. The rails 11 are disposed at the ends of the rows of electrodes and are secured to the two outermost impact bars, for example by angles lla, so that the outermost bars 4 serve as the sole support for the rail 11.

In the embodiment shown in the drawings, the laterally-extending rails 11 are provided with depending baffie plates 12 which prevent any substantial amount of gas introduced into the electrostatic precipitator to be purified from flowing longitudinally Within the space beneath the electrodes.

Where the electrostatic precipitator has substantial width, the laterally-extending rails 11 are preferably divided into a plurality of flexibly interconnected rail sections, each section being carried by the impact bars. To this end, a joint and spacing member 13 is provided to interconnect two adjacent rail sections, 538 shown in FIG. 2.

While a particular embodiment of the present invention has been herein illustrated and described, it is not intended to limit the invention to such disclosure, but changes and modifications may be made therein and thereto within the scope of the following claims:

What we claim is:

1. An electrostatic precipitator comprising:

a casing arranged for horizontal gas flow therethrough,

plate-shaped collecting electrodes disposed parallel to and arranged. intranswhich are, parallel an elongatedimpact bar underlying eachrow of electrodes and coextensive therewith;

' hammer means within said casing for each'impact bar' operable upon'actuation thereof to engage and dis-. place said bar longitudinally in the direction of gas flow through said precipitator,

abutment means on said, impact bar engaging each 1' of said electrodes in the associated row to effect oscillatory movement of said electrodes" in the di-' rection of gas flow upon actuation of said hammer means, and 'in'cluding means at each end of *each for swingimpact bar to suspend said bar from" said outermost electrodes,

laterally extending rails adjacent the ends of'the rows of electrodes, a'nd means at each end of each rail;

securing said rail to the impact bar adjacent each end to suspend the rail therefrom, said means being the sole support for said rails,

a U-shaped guide bracket mounted on said 'rail to embrace each impact 'bar and guide it against lateral movement while permitting free. thermal expansion of said collecting electrodes,.and battle plates se cured to and depending from said laterally extending rails and operable to prevent any substantial amount a of the gas from flowing longitudinally within the space beneath the electrodes. 2. Apparatus according to claim 1 wherein said laterally-extending rails, at each'end of the impact bars are divided into a plurality of aligned separate rail "sections; each suspended from two impact bar s adjacent 7 its ends,randi including flexible connecting- 7 connecting said trail sections. 1

means inter- 1 References Cited by the Examiner UNITED "STATES PATENTS 1,882,949 10/32 Ruder, V 2,595,204 4/52 Richardson 55-112 7 2,703,630 3/55- CroWder ss 300 2312035; 11/57 Sohlmanet a1; 55-430 X 2,864,459J12/58, Gustafsson 55-7108 X FOREIGN PATENTS 75143737 1152 Belgium. 509,898 '11/20' France.

373,773 4/23 Germ-any. 450,391 10/27 -Germany. 7 437, 20 11 35" Great Britain. 4

790,130 "258 Great Britain; HARRY B; THORNTioN,-Primaryr Examiner. I

WALTER BERLOWITZ,

Claims

1. AN ELECTROSTATIC PRECIPITATOR COMPRISING: A CASING ARRANGED FOR HORIZONTAL GAS FLOW THERETHROUGH, PLATE-SHAPED COLLECTING ELECTRODES DISPOSED PARALLEL TO THE DIRECTION OF GAS FLOW AND ARRANGED IN TRANSVERSELY-SPACED LONGITUDINAL ROWS WHICH ARE PARALLEL TO THE GAS FLOW, MEANS SUSPENDING SAID COLLECTING ELECTRODES FOR SWINGING MOVEMENT IN SAID CASING, AN ELONGATED IMPACT BAR UNDERLYING EACH ROW OF ELECTRODES AND COEXTENSIVE THEREWITH, HAMMER MEANS WITHIN SAID CASING FOR EACH IMPACT BAR OPERABLE UPON ACTUATION THEREOF TO ENGAGE AND DISPLACE SAID BAR LONGITUDINALLY IN THE DIRECTION OF GAS FLOW THROUGH SAID PRECIPITATOR, ABUTMENT MEANS ON SAID IMPACT BAR ENGAGING EACH OF SAID ELECTRODES IN THE ASSOCIATED ROW TO EFFECT OSCILLATORY MOVEMENT OF SAID ELECTRODES IN THE DIRECTION OF GAS FLOW UPON ACTUATION OF SAID HAMMER MEANS, AND INCLUDING MEANS AT EACH END OF EACH IMPACT BAR TO SUSPEND SAID BAR FROM SAID OUTERMOST ELECTRODES, LATERALLY EXTENDING RAILS ADJACENT THE ENDS OF THE ROWS OF ELECTRODES, AND MEANS AT EACH END OF EACH RAIL SECURING SAID RAIL TO THE IMPACT BAR ADJACENT EACH END TO SUSPEND THE RAIL THEREFROM, SAID MEANS BEING THE SOLE SUPPORT FOR SAID RAILS, A U-SHAPED GUIDE BRACKET MOUNTED ON SAID RAIL TO EMBRACE EACH IMPACT BAR AND GUIDE IT AGAINST LATERAL MOVEMENT WHILE PERMITTING FREE THERMAL EXPANSION OF SAID COLLECTING ELECTRODES, AND BAFFLE PLATES SECURED TO AND DEPENDING FROM SAID LATERALLY EXTENDING RAILS AND OPERABLE TO PREVENT ANY SUBSTANTIAL AMOUNT OF THE GAS FROM FLOWING LONGITUDINALLY WITHIN THE SPACE BENEATH THE ELECTRODES.