US3707828A

US3707828A - Precipitator cell

Info

Publication number: US3707828A
Application number: US00049443A
Authority: US
Inventors: I Burney
Original assignee: Westinghouse Electric Corp
Current assignee: AMERICAN DAVIDSON Inc
Priority date: 1970-06-24
Filing date: 1970-06-24
Publication date: 1973-01-02
Anticipated expiration: 1990-01-02
Also published as: GB1306314A; CA946754A

Abstract

A precipitator cell is provided with a plurality of spaced alternately oppositely charged collecting plate electrodes with certain spaced ones of the electrodes with the same one polarity of charge being projected to extend beyond the remainder of the plates in the direction against the direction of the gas flow to thereby form ionizing zones. Cantilever spring support means of electrically conductive sheet material are connected at their bases from respective ones of the electrodes of the other polarity so as to have their free-ends cantilevered out over the ionizing zones. Ionizing wires are connected under tension between the spring support means to span the ionizing zones between the extension of the plate electrodes of the one polarity.

Description

United States Patent 1191 Burney 51 Jan. 2, 1973 1 PRECIPITATOR CELL 3,149,937 9/1964 Revell ..ss 147 x 3,404,785 10/1968 Ema ..211 183 [75] Bumcy Pmsburgh 3,473,097 10/1969 Barn? 317/222 E [73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa. Primary Examiner-Dennis E. Talbert, Jr. [22] Filed: June 24, 1970 Attorney-F. H. Henson and F. E. Blake [21] Appl. No.: 49,443 [57] ABSTRACT A precipitator cell is provided with a plurality of [52] US. Cl. ..55/l38, 55/143, 55/145, spaced alternately oppositely charged collecting plate 55/147, 55/148, 55/151, 55/154, 211/153 electrodes with certain spaced ones of the electrodes [51] Int. Cl ..B03c 3/40 wi h ame one polarity of charge eing projected [58] Field of Search ..55/l36-l38, 140-148, o extend y n h remainder of the pla in h 551150-153, l54;2l1/l53, 183 direction against the direction of the gas flow to thereby form ionizing zones. Cantilever spring support [56] References Cited means of electrically conductive sheet material are connected at their bases from respective ones of the UNITED STATES PATENTS electrodes of the other polarity so as to have their 2,160,044 5/1939 Warren ..ss/1so ux I free-ends camilevefed the ionizing Zones- 2,973,055 2/1961 Aitkenhead Ionizing wires are connected under tension between 2,796,948 6/1957 Fields the spring support means to span the ionizing zones 2,987,137 6/1961 Brixius et al.. between the extension of the plate electrodes of the 3,016,980 1/1962 Gonzalez one polarity. 3,040,498 6/1962 Berl 3,073,094 1/1963 Landgraf et al. ..55/ 151 X 3 Claims, 4 Drawing Figures PATENTEDJAH2 I975 SHEET 1 OF 2 INVENTOR Burney BY ATTORNEY PATENTED ms 3.707.828

' sum 2 [IF 2 FIG.2.

PRECIPITATOR CELL CROSS REFERENCE TO RELATED PATENT APPLICATIONS So far as is known, this invention is not related to any pending patent applications.

BACKGROUND OF THE INVENTION Precipitator cells of the type having a plurality of spaced alternately oppositely charged collecting plate electrodes are well known and such cells are generally arranged to have ionizing zones ahead of the collecting plates against the direction of the gas flow through the cell. In some arrangements the ionizing zones are formed between extensions of some of the plate electrodes having the same charge of one polarity. In order to ionize the gas flowing through the ionizing zones into between the collecting cell electrodes, a plurality of respective ionizing wires to be charged with the other polarity are each supported to be spanned between the plate electrode extensions forming the ionizing zones. Problems have been encountered in properly supporting the wires in a manner that would properly locate the wires between the plates yet enable the wires to be easily replaced. Also the supporting structures for the wires should be simple and economical to manufacture and yet should be able to maintain the required resilience forproper tension of the ionizing wire over the useful life of the cell. Since the supporting structures for the ionizing wires are themselves effectively a dead zone ionizing region, I have found that it is desirable for the frontal profile of the supporting elements to be shaped toprovide a baffling of the gas flow in the dead zone region.

PRIOR ART 3,149,937 Revell f I Sept. 22, 1964 3,041,807 Getzin et al. July 3, 1962 3,027,970 Mueller Apr. 3, 1962 SUMMARY OF THE INVENTION In accordance with the invention, a wire support is t formed of resilient sheet electrically conductive material such as stainless steel or the like. Each support is of a cantilever spring arrangement supported; by a spring clip at its base and cantilevered out over the ionizing zones from respective ones of the electrodes having the other polarity with respect to the polarity of the projecting plates forming the ionizing zones. In the preferred form of the invention, each support extends over more than one ionizing zone to support a respective ionizing wire for each respective ionizing zone, thus accurately locating the ionizing wires relative to each other and the associated ionizlng plate electrodes. The support base is preferably attached to an inwardly extending slot on the edge of the associated plate electrode. In order to provide a desirable shape for each spring support over the respective ionizing zone, the cantilevered portions of the spring support are shaped to form spring fingers tapering from a wide base to a narrow tip at which the ionizing wires are removably secured. The tapered shape of each spring finger thus formed is effective to provide a flexing portion which approximates a constant stress spring for long life. Also the tapered shape of the spring finger forms a frontal profile for the support strip that helps in baffling the air flow around the support finger which is effectively a dead zone for ionizing purposes.

Further features and advantages of the invention will be apparent with reference to the following specification and drawings:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of the line I-I of FIG. 2 as seen in the direction of the arrows transverse to the air flow:

FIG. 2 is a fragmentary top plan view partly broken away in section;

FIG. 3 is a perspective elevational view of one of the spring support members of the invention; and

FIG. 4 is a fragmentary detailed view showing how a spring support member is supported on an associated one of the plate electrodes to extend out over the ionizing zone.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2 of the drawings, the general arrangement of the precipitator cell will be described. Each end of the precipitator cell is provided with an end supporting structure such as shown at 10 to which are bolted the supporting and spacing rods for the collecting plates in the assembled relation. The rods such as shown at 11 and 12 are supported on suitable insulators such as shown at 13 to be charged with a polarity opposite to the polarity of the end plate supporting structure 10. Others of the supporting rods such as shown at 14 and 15 are connected directly to the end plate supporting structure 10 and are therefore arranged to be electrically charged the same as the end plate structure 10.

A plurality of collecting plates are secured to the respective support rods l1, 12, 14 and 15 in a fashion such that alternate ones of the plates such as shown at 16 and 17 are charged with opposite polarity. As will be seen, for example, the plate electrode 17 is secured to the support bolt 14 by means of the spacer collar or sleeve 18. Thus the electrode 17 assumes the charge with the polarity of the support bolt 18 and the end supporting structure 10. On the other hand, alternate ones of the collecting plates, such as the collecting plate 16 are secured to the bolt 11 by means of the spacing sleeve or collar 19 and assumes a charge with the polarity corresponding to the polarity of the rod 1 1 that is supported on the insulating structure 13 from the supporting end structure 10. An electrical lead (not shown) may be connected from the rods such as rods 11 and 12 to the precipitator power supply having a high voltage direct current of one polarity with the other polarity of the power supply being connected to the end structure 10 through an electrical lead (not shown). The collecting plates of one polarity such as the collecting plates shown at 17 are provided with apertures such as shown at 21 through which the charged supporting rod 11 of the opposite polarity extends. Similarly, each of the collecting plates charged with the other polarity such as collecting plate 16 are provided with an aperture such as shown at 22 through which the supporting rod 14 which is charged to the one polarity extends. Thus a stack of spaced charged collecting plate electrodes with alternate one of the collecting plates having opposite polarity charges is formed through which gas may flow for precipitating contaminants on the collecting plates when the contaminant particles in the gas are suitably charged by ionization or the like.

For purposes of ionizing the charged particles in the gas flow before they pass into the collecting plate regions, a plurality of ionizing zones such as those shown at 30, 40 and 50 are provided. Each ionizing zone such as the zone 40 is formed in the space between charged electrodes such as

electrodes

41 and 42 projecting beyond the majority of the plates in the cell. The projecting

plate portions

41 and 42 are of the same polarity charge since they are extensions of plates that are supported on the support rod 14 and insulated from the support rods such as the support rods 11 and 12. A plurality of ionizing wires are arranged to be disposed with a respective wire in a respective ionizing zone such as the ionizing wire 43 for zone 40. The respective ionizing wires are supported under tension to span the ionizing zone centrally between the ionizing plates and of course each ionizing wire should be charged with a polarity opposite to the polarity of the respective

ionizing zone plates

41, 42, etc.

In accordance with the invention, a supporting structure for the respective ionizing wires such as the

wires

33, 43 and 53 is comprised of upper and lower supporting members such as the member 60 shown by FIG. 3 of the drawing. The lower support member is shown at 70 by FIG. 1 of the drawing. Each

support member

60, 70 is substantially identical and is formed of a resilient sheet material of electrically conductive nature such as stainless steel or the like. The sheet material is formed with a base spring clip 68 most clearly shown by FIGS. 3 and is adapted to be received in the respective electrode plate slots such as shown at 62 (FIG. 4). Those plate electrodes such as electrode 41a having the supporting slots for the spring support 60 are selected to have the same polarity of charge which is opposite to the polarity of charge of the charge of the plates such as 41, 42 forming the ionizing zone. For example the spring support member 60 is supported from

electrodes

16, 17a, 41a and 42a while the

electrodes

17, 41, 41b and 42 are notched such as shown at 45 to provide a clearance for the base 61 of the spring support 60. Similarly the lower spring support 70 is supported within suitable slots of selected ones of the collecting plates having the same polarity charge that is opposite the polarity of the electrode plate extensions.

In the preferred form of the invention, each support member, such as the member 60, is formed with a plurality of spring fingers 61-67 projecting from a wide base portion adjacent the base 68 to taper to a narrow pointed end overlying the respective associated ionizing zone in the assembled relation. Each tapered end of the spring finger, such as spring finger 61, is provided with a slot such as shown at 61a within which is received the end of the ionizing wire such as the wire 43 shown by FIG. 4 of the drawings. In practice, the ionizing wire is precut to a desired length and provided with crimped ends or hat members such as shown at 42a. Thus when it is required to replace an ionizer wire it is only necessary to depress an associated spring finger and slip the wire into or out of the slots at the end of the associated spring fingers. After replacement, when the spring finger is released, the ionizer wire will be supported and held in proper tension and in the correct location in the ionizing zone. Inasmuch as there are two or more spring fingers 61-67 formed in a single unitary sheet of spring material, the positions of each ionizing wire within its associated ionizing zone will be accurate predetermined and prerelated to each other and it is only necessary to properly locate the support member to correctly locate all of the ionizer wires supported by the support member.

The previously described tapered form of the respective spring fingers 61-67 assures a desirable spring action that will remain substantially unchanged over the entire life of the precipitator cell. In effect the tapered shape of each respective spring finger, 61-67, provides a flexing portion approximating a constant stress spring. In addition, I have found that the particular tapered shape for the spring finger provides an effective baffling for the gas flow through the precipitator cell in the region of the ionization dead zone that is inherent adjacent to the spring finger structure.

Various modifications will occur to those skilled in the art.

I claim:

1. An electrostatic precipitator cell having a plurality of spaced collecting plate electrodes with alternate electrodes adapted to have opposite polarity charges, regularly spaced ones of these electrodes having the same charge of one polarity being projected beyond the remainder of said plates in the direction against the direction of gas flow through the precipitator to form ionizing zones, upper and lower ionizer wire spring support means for receiving, locating and supporting ionizer wires under tension, each said support means formed of electrically conductive resilient sheet material and having a base portion and a cantilevered ionizer support portion extending therefrom along substantially the whole length of each respective base portion, each of the base portions being formed from the respective sheet material as a depending spring clip extending substantially the whole length of the respective base portion, support means spanning more than one of said ionizing zones, said plate electrodes of the other polarity charge being provided with upper and lower inwardly extending edge slots receiving therein respectively the depending spring clip base portion of the respective upper and lower support means in supporting and electrically conductive relation, and a plurality of respective ionizer wires of electrically conductive material each supported in electrically conducting contact with and under tension between the respective upper and lower cantilevered ionizer support portions of said support means, said ionizer wires spanning the respective ionizing zones and charged with the other polarity between said regularly spaced projecting plates of the one polarity charge.

2. The invention of claim 1 in which the cantilevered free ends of each support are shaped as spring fingers of tapered form from a wide base to a narrow tip over each ionizing zone.

3. The invention of claim 1 in which the cantilevered free ends of each support are shaped as spring fingers of tapered form from a wide base to a narrow tip over 5 each ionizing zone.

Claims

3. The invention of claim 1 in which the cantilevered free ends of each support are shaped as spring fingers of tapered form from a wide base to a narrow tip over each ionizing zone.