US2852093A - Discharge electrode - Google Patents

Description

P 1958 R. G. STREUBER 2,852,093

DISCHARGE ELECTRODE 4 Sheets-Sheet 1 Filed April 16, 1956 INVENTOR RUDOLF G. STREUBER BY Aw/zymz/ ATTORNEY Sept. 16, 1958 R. s. STREUBER 2,852,093

DISCHARGE ELECTRODE Filed April 16,, 1956 4 Sheets-Sheet 2 y INVENTOR RUDOLF s. STREUBER BY w 4/7M ATTORNEY Sept. 16, 1958 R. G. STREUBER 2,852,093

DISCHARGE ELECTRODE Filed April 16, 1956 v 4 Sheets-Sheet 3 a n L I IT I W I 46 I i q if so 4e 44 42 I INVENTOR RUDOLF G. STREUBER ATTORNEY Sept. 16, 1958 R. G. STREUBER 2,852,093

DISCHARGE ELECTRODE Filed April 16, 1956 4 Sheets-Sheet 4 INVENTOR RUDOLF G. STREUBER ATTORNEY United States Patent DISCHARGE ELECTRODE Rudolf G. Streuber, Bridgewater Township, Somerville, N. J., assignor to Research-Cottrell, Inc., Bridgewater Township, Somerset County, N. J., a corporation of New Jersey Application April 16, 1956, Serial No. 578,281

1 Claim. (Cl. 1837) This invention relates to electrical precipitation apparatus and more particularly and specifically to new and improved discharge electrode assemblies and to the individual discharge electrodes thereof.

Discharge electrodes for precipitation apparatus have been constructed with ribbon-like configurations and have been individually suspended within precipitator structures. However, these ribbon-type discharge electrodes have been susceptible to several operational disadvantages such as the tendency to form hot spots on the electrode, poor corona effect, sailing action of the electrode, and arcing and back corona discharge caused by sailing; all of which disadvantages have substantially reduced their eificiency.

It is, therefore, a general object of this invention to provide a new and improved discharge electrode structure including a ribbon-like electrode for the purpose of obtaining the advantages of such an electrode configuration which are well known in the art, yet providing an electrode of the ribbon type which avoids those disadvantages inherent in prior ribbon electrodes.

An object of this invention is to provide a ribbon-type discharge electrode which permits the operation of an electrical precipitator at maximum efficiency and with the minimum of problems heretofore inherent in ribbontype electrode assemblies.

A further object of this invention is the provision of a ribbon-type electrode which is so constructed as to obtain the maximum corona effect While avoiding the creation of hot spots and arcing within the precipitation zone.

A still further object of this invention resides in the provision of a ribbon-type discharge electrode for electrical precipitation apparatus which enablesthe attainment of corona discharge at minimum potential requiremerits and potential requirements lower than those heretofore required with prior round wire or ribbon-type electrodes.

Another object of this invention is the provision of a ribbon-type discharge electrode which is equally effective when incorporated in precipitation apparatus employing either tube or plate type collecting electrode structures.

Still a further object of the invention is the provision of ribbon-type discharge electrodes in combination with a rigid supporting frame which tautly suspends the electrodes within the precipitator and prevents them from swaying or blowing out of spaced relationship with the collecting electrode assembly.

Another and still further object of the present invention is the provision of ribbon-type electrode structures and supporting frames therefor wherein the electrodes are readily adapted to stiffeningor crossbracing intermediate their length for the. purpose of reducing possible sail eifect of the electrode without reductionin etficiency or disturbance of corona effect incurred through the use of. such stiflening or brace members.

Yet. another object and advantage of thisinvention is (d the provision of a new and improved ribbon-type discharge electrode having an evenly corrugated configuration providing evenly and alternately spaced edges between the angular segments thereof forming corona discharge Zones which maintain uniform, effective spark distance throughout the entire length of the electrode.

Still another object and advantage of this invention is the pro-vision of a new and improved ribbon-type discharge electrode having angular alternate corrugations throughout a substantial portion of its length which is quickly and easily assembled in or removed from the precipitator apparatus by reason of its novel combination with a rigid supporting frame for the electrode located within the precipitator apparatus.

Another object and advantage of this invention is the provision of a corrugated, ribbon-type discharge electrode in combination with a rigid supporting frame wherein the frame tautly supports the electrode within the precipitator apparatus thereby eliminating the necessity of utilizing weights for maintaining electrode alignment, While at the same time the structure of the electrode has sufiicient inherent resilience to permit elimination of the costly spring elements heretofore required for mounting and suspending such electrodes within precipitation apparatus.

Still a further object and advantage of this invention is the provision of a new and improved ribbon-type electrode which is of extremely simple and inexpensive design and manufacture and which is efiicient and durable over extended periods of use.

Still other objects and advantages of this invention Will become more readily evident to those skilled inthe art when the following general statement and description are read in the light of the accompanying drawings.

The nature of the present invention may be stated in general terms as relating to a ribbon-type discharge electrode in combination with a rigid rectangular frame wherein the electrode comprises an elongated conductive strip of ribbon-like configuration having hook means at each end for engaging about the opposite end pieces of the rigid frame, said ribbon-like member being corrugated throughout a substantial portion of its length interrnecliate its ends, said corrugations taking the form of alternate angular segments formed to extend for equal distance. outwardly from the longitudinalcenterline of the strip, and the angular relationship of said segmentsgbeing equal throughout its corrugated length.

Referring now to the accompanying drawings in which like numerals designate similar parts throughout the several views:

Fig. 1 is a vertical section through an electrostatic precipitator having the discharge electrodes constituting the present invention located therein.

Fig. 2 is a vertical section through a precipitator apparatus taken at right angles to Fig.

Fig. 3 is a pictorial illustration of a discharge electrode conforming to the present invention.

Fig. 4 is a fragmentary view similar to Fig. 2 illustrating a modified form of the electrode structure.

Fig. 5 is a view similar to Fig. 4 showing stilla further modification of the electrode structure including antiswing weights intermediate the electrode length.

Fig. 6 is a fragmentary pictorialview illustrating a weighted segment of the electrode disclosed in Fig; 5.

Fig. 7 is an enlarged side elevation ofthe weighted segment disclosed in Fig. 6.

Fig. 8 is an elevational view of a modified form of the electrode assembly including a stabilizing brace.

Fig. 9 is a vertical section taken on line9-9, Fig. 8..

Fig. 10 is an enlarged fragmentary section disclosing the brace attachment to the modified electrode; disclosed in Fig. 8..

usual hopper bottom 16 for receiving and discharging precipitated materials from the housing.

Plate-type collecting electrodes 18 are supported longitudinally of the housing between the gas inlet and the gas outlet in parallel spaced relationship. The collecting electrodes are suspended from top supporting bars 20 which in turn are supported from brackets 22 secured to the inner walls of the housing adjacent its upper end.

Associated with the spaced parallel collecting plate members is a plurality of discharge electrodes 24 which are arranged in spaced relationship in parallel rows intermediate the collecting plate electrodes 18. In the present embodiment a high tension frame 26 is suspended transversely above the upper ends of the spaced collecting plate electrodes from an insulator support 28 mounted in conventional manner within a housing 30 carried on the top of the precipitator housing.

Associated with the high tension frame 26 is a plurality of rigid rectangular frames 32 each of which is suspended vertically from the high tension frame in parallel spaced relationship equidistant between two spaced collecting electrode plates 18. The frame 32 is somewhat greater in length vertically of the housing than the vertical length of the collecting electrodes 18 so that when positioned within the housing the frame extends for a spaced distance above and below the upper and lower ends of the collecting plates. Associated with each rigid frame 32 is a plurality of discharge electrodes 24 which are arranged in equally spaced relationship longitudinally of the upper and lower end members of the frame and which are positioned to extend vertically within the housing intermediate the upper and lower endmernbers of the frame. Each of the collecting electrodes 24 takes the form of an elongated metallic ribbon formed from a flat sheet with each of the ribbon members being evenly corrugated as at 34 through a substantial portion of its length intermediate the extended ends thereof wherein the corrugated portion of each electrode is formed by alternately crimping the opposed flat faces through a substantial portion of its length in such a manner as to present on opposite sides thereof alternate folded edges 36 extending transversely of the ribbon with alternate edges on opposite sides or faces of the ribbon projecting equidistant outwardly from the centerline of the ribbon established between the uncorrugated portions 38 at each end thereof.

For example, a metallic ribbon of light gauge stainless steel or the like of approximately to 4-inch wide and of about 20 gauge may be corrugated by passing the strip through suitably faced rolls, or such a sheet could be stamped, to provide the corrugations. Corrugations approximately of an inch in depth to provide each peak portion, or folded edge 36 as described, to extend inch outwardly from the longitudinal centerline of fi-inch ribbons as established between the flat uncorrugated end portions has been found to give satisfactory results. For a ribbon 42-inch wide, the depth of the corrugations would be about A3 to about /2 inch.

However, it will be understood that the depth of corrugation can be varied to fit variations in plate spacings between top and bottom sections of a plate.

In the embodiment disclosed in Figs. 1, 2 and 3, the extended ends of each ribbon electrode are provided with a hook member 40 formed integrally therewith and adapted to detachably engage the upper and lower end members of the rigid frame 32 for the purpose of releasably mounting the electrode longitudinally of the frame. By providing the electrode of an over-all length slightly less than the over-all vertical length of the frame 32 it becomes necessary to longitudinally flex the electrode, the corrugated portion of which provides limited longitudinal flexibility, to tautly mount the electrode on the frame under constant longitudinal tension. By mounting the electrode on the frame under longitudinal tension the electrode, in addition to being held firmly in place, is deterred from swaying movement or sailing effect common in precipitator apparatus employing ribbon-like electrodes and, at the same time, expansion of the electrode due to increased heat in the precipitator will not cause the electrodes to sag.

From the foregoing, it can be readily seen that a new and unique collecting electrode structure has been provided including a ribbon-type electrode having a corrugated section throughout a substantial portion of its length which is positioned intermediate the collecting plates of electrical precipitation apparatus. The folded edges on opposite sides of the ribbon electrode are normally disposed opposite the collecting plates 18 and provide highly efficient corona discharge points for maintaining a maximum corona discharge efiiciency within the precipitation field and the uniformity of corrugation and extension of such corona points equidistant on opposite faces of the ribbon-type electrode provide a uniform distance between the discharge points on opposite sides and the collecting plates associated respectively therewith.

It is known that efficient corona discharge may be obtained at considerably lower potentials from sharp points or edges; therefore, the corrugated electrode structure herein disclosed enables the utilization of lower potentials than have been heretofore usable in precipitation apparatus employing fiat or round wire discharge electrodes.

At the same time it is seen that utilization of a rigid frame mounting the discharge electrodes in the manner described tends to avoid the problems of swaying and sailing effect which are usually inherent in prior structures which have heretofore utilized weights or the like on the lower extended ends of the electrodes for the purpose of maintaining electrode alignment.

In Fig. 4 of the drawings there is shown a construction wherein the plate-top collecting electrodes 18 are provided at equally spaced points intermediate their vertical length with stiffening ribs 42 which extend, in conventional manner, transversely of each plate and provide a thickened plate section at their point of attachment or formation which produces projecting surfaces 44 outwardly from either face of the collecting plate 18. Where such a stiffening rib is provided in the collecting plates of precipitation apparatus a discharge electrode 46 formed basically in the manner and configuration of the electrode 24 heretofore described is utilized by locating it in conventional manner intermediate two parallel spaced collecting plates 18. However, the corrugated section or portion of the electrode 46 is modified by providing a flat segment 48 in the electrode immediately adjacent the projected surface 44 of the stiffening rib 42 in the collecting plate. The extended length of the fiat segment 48, which lies on the centerline intermediate the flattened end portions of the electrode, is determined by the extent of projection of the surfaces 44 outwardly from the normal plane of the face of the collecting plate electrode. The extent is predetermined so as to prevent any reduction in the sparking distance between the discharge electrode and the projected surface areas 44 of the rib and is such as to maintain the distance between the flattened segment and the projected surfaces of the rib as nearly equal as possible to the normal sparking distance between the folded edges 36 of the electrode and the normal plane of the face of the collecting plate.

In Figs. 5 through 7 of the drawings, there is illustrated method and apparatus for attaching to a ribbontype electrode constructed in accordance with the above described invention anti-swing weightsat spaced intervals longitudinally of the electrode. By providing short flattened segments 50 in the corrugated section of the electrode at spaced intervals along the electrode length dampening or anti-swing weights taking the form of a pair of identical rhombic blocks 52, each of which has equal angular converging side walls 54 may be secured to either side of the flat segment with the corresponding long side of each member being seated against the opposite faces of the flat segment. Bolts 56, rivets or the like may be utilized to firmly secure the blocks to the opposite faces of the flat segments. The extended measurement of each block perpendicular to the plane of the flat segment is identical to the distance each of the folded edges 36 is off-set from the centerline of the electrode thereby maintained between the swing weight and the adjacent collecting plates a sparking distance equal to the sparking distance between each of the folded edges 36 in the corrugated section of the electrode.

By utilizing dampening or anti-swing weights constructed in accordance with the foregoing disclosure and assembled in combination with an electrode of the type defined, uniformity of corona discharge is maintained throughout the length of the electrode while at the same time swaying and sailing effect are substantially eliminated.

In Figs. 8 through 10 of the accompanying drawings, there is disclosed method and apparatus for providing a stiffening brace for the discharge electrodes at a point intermediate their length. There is also disclosed a modification of the corrugated electrode to accommodate a stiffening brace in such a manner as to avoid the creation of any non-uniformity in the spark distance between any point on the electrode and an adjacent collecting plate.

In these views there is shown a ribbon-type electrode 58 having a fiat segment 60 therein at a point equidistant between its ends wherein the flat segment 60 is provided centrally of its length with an angular crimped section 62 outwardly of one face of the segment. The angularity and dimension of the crimped section 62 substantially coincides with the angularity and dimensions of a diamond-shaped tubular rib or brace 64, two sides of which are received and secured by rivets 66 or the like in the crimped section 62 of the fiat segment 60. The extended ends of the rib or brace are rigidly secured as at 68 to 6 is provided between the apex of the crimped section and the oppositely extending corner 70 of the rib 64 and the collecting plates adjacent thereto which is equal to the spark distance maintained between the folded edges 36 on each side of the ribbon-type electrode and the collecting plate surfaces adjacent thereto.

Thus, it can be seen that a rigid brace or stitfening rib has been provided for the collecting electrodes to deter them from sailing or swaying within the precipitator housing while maintaining uniform corona discharge throughout the length thereof.

In Fig. 11 of the drawings a ribbon-type electrode 24 constructed in accordance with the present invention is shown suspended centrally within a tubular collecting electrode 72. In this embodiment of the invention it will be seen, as illustrated by broken line that corona discharge will occur between the electrode 24 and substantially all surfaces of the tubular electrode 72 thereby providing a highly eflicient precipitation field. It will be evident that dampening or anti-swing weights can be utilized with the electrode 24 within a tubular collecting electrode in the same manner heretofore described and with the same advantageous results.

Thus having described the novel construction and new and useful results obtained from the present invention, what is desired to be claimed is:

In combination with an electrical precipitator, an extended surface electrode, complementary discharge electrodes comprising elongate metallic ribbons being corrugated laterally of the opposed fiat faces to provide a continuous series of substantially symmetrical ridges and grooves substantially throughout the ,length thereof, supporting means provided to maintain said discharge electrodes in substantially parallel spaced relationship relative to said extended surface electrode, and a rigid rib member secured between opposed sides of said supporting means, said rib member registering with and being secured in the corrugations formed in said discharge electrodes intermediate opposed sides of said supporting means.

References Cited in the file of this patent FOREIGN PATENTS 487,444 Germany Dec. 12, 1929 694,603 France Sept. 16, 1930 718,611 France Nov. 4, 1931 868,429 France Sept. 29, 1941

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