US3920085A

US3920085A - Swing hammer rapping system for electrostatic precipitator

Info

Publication number: US3920085A
Application number: US522672A
Authority: US
Inventors: Bernard J Bourke
Original assignee: Universal Oil Products Co
Current assignee: Honeywell UOP LLC; Universal Oil Products Co
Priority date: 1974-11-11
Filing date: 1974-11-11
Publication date: 1975-11-18
Anticipated expiration: 1992-11-18

Abstract

The jarring of the electrodes, either the collector plates or the high voltage discharge wires, or both, of an electrostatic dust precipitator is provided through the use of swing hammers that are rotated from power-operated shafts that are located above the spaced rows of electrodes such that both the shafts and the hammers are above the roof of the gas chamber and out of the path of the particle laden gas stream. In a typical improved system, where a plurality of collector plates are suspended from grounded, spring supported cross beams, there will be vertical rods extending upwardly from these supporting beams and through the precipitator roof to the area of the rotating swing hammers, whereby there can be provided the periodic transmission of rapping blows from the hammer means down to the various supporting cross beams and thence to the electrodes such that particles will be dislodged therefrom. Similarly, grounded swing hammer means above the roof and the support framing for the high voltage discharge electrodes can be located in a penthouse area to strike upwardly extending rods from the electrode framing and thereby dislodge particles from the high voltage discharge electrodes.

Description

United States Patent [191 Bourke Nov. 18, 1975 [75] Inventor: Bernard J. Bourke, White Plains,

[73] Assignee: Universal Oil Products Company, Des Plaines, Ill.

[22] Filed: Nov. 11, 1974 21 Appl. No.: 522,672

[52] US. Cl 173/99; 55/112 [51] Int. Cl. 1303C 3/76 [58] Field of Search 173/99; 55/112; 318/37 [56] References Cited UNITED STATES PATENTS 643,039 2/1900 Calvert et al. 173/99 1,903,644 4/1933 Meston 55/112 1,974,226 9/1934 Wintermute .1 55/112 2,777,535 1/1957 Hull 55/112 3,570,217 3/1971 Steuernagel 173/99 3,835,817 9/1974 Tuomaala 173/99 FOREIGN PATENTS OR APPLICATIONS 1,133,343 7/1962 Germany 55/112 Primary Examiner-James A. Leppink Attorney, Agent, or FirmJames R. Hoatson, Jr.; Philip T. Liggett; William H. Page, II

[57] ABSTRACT The jarring of the electrodes, either the collector plates or the high voltage discharge wires, or both, of an electrostatic dust precipitator is provided through the use of swing hammers that are rotated from power-operated shafts that are located above the spaced rows of electrodes such that both the shafts and the hammers are above the roof of the gas chamber and out of the path of the particle laden gas stream. In a typical improved system, where a plurality of collector plates are suspended from grounded, spring supported cross beams, there will be vertical rods extending upwardly from these supporting beams and through the precipitator roof to the area of the rotating swing hammers, whereby there can be provided the periodic transmission of rapping blows from the hammer means down to the various supporting cross beams and thence to the electrodes such that particles will be dislodged therefrom. Similarly, grounded swing hammer means above the roof and the support framing for the high voltage discharge electrodes can be located in a penthouse area to strike upwardly extending rods from the electrode framing and thereby dislodge particles from the high voltage discharge electrodes.

9 Claims, 6 Drawing Figures US. Patent Nov. 18, 1975 3,920,085

SWING HAMMER RAPPING SYSTEM FOR ELECTROSTATIC PRECIPITATOR This invention relates to a rapping system for dislodging particulates which have been drawn to, or deposited on the electrodes in an electrostatic precipitator unit.

More particularly, the invention is directed to a rapper system which uses free-falling swing hammers to impart blows to rodswhich extend upwardly from the electrode support means and through the roof of the precipitator chamber, with the resulting arrangement being such that the rotating shafts and the hammers are maintained out of the path of the particle laden gas stream.

BACKGROUND OF THE INVENTION the rapper systems use timed cycle means for lifting and letting fall a series of weights or hammers, or for operating electromagnetic solenoids, that will cause a jarring of the electrodes through their support framing in the gas flow path.

While free-falling, swing hammers similar to those used in the present improved system have been in use for many years, it should also be pointed out that the known operations have had the rotating shafts and the hammers in the main chamber so as to be in the electrode zone and in the path of the gas stream. Each hammer arm is usually attached by a hinge pin to a fixed arm on a slowly rotating shaft such that as the shaft slowly turns the hammer arm is picked up and lifted to a vertical position and then subsequently turned over to swing down and strike a blow to a hammer pad which vibrates the electrode assembly. In these operations, neither the hammer shaft nor the internal bearings can be inspected or serviced without gaining access to the' gas chamber during a shutdown period. Also, the intensity of the hammer blows cannot be adjusted without access to the interior of the gas chamber. In contrast, the present improved upper system maintains the hammers and rotating shafts entirely above the electrodes and outside of the gas chamber of the unit.

In addition to swing hammer rapping means, there have been some usage of electromagnetic rappers where timed cycles in conjunction with series resonat circuits can effect hammer-like blows which, in turn, can be transmitted to the particle collector plates or to the support frames for the particular electrodes. For example, one such type of system is described in US. Pat. No. 3,172,027. While such systems are adjustable, they do have the economic disadvantage of requiring high voltage equipment and circuitry that is costly to install and to maintain.

SUMIVIARY OF THE INVENTION Since there are certain economic advantages to using free-fall, swing hammer means to effect the rapping of electrode support means, it is a principal object of the present invention to provide an improved rapper system where the hammers, shafts, bearings, and other mechanical parts are out of the interior portion of the precipitator and out of the gas stream zone.

It is also an object of the present invention to provide a swing hammer rapper system where the hammers, power-operated shafts, bearings, etc., are above the precipitator roof and in a penthouse area, to thus be out of the path of the gas stream flow through the unit, but will be able to indirectly contact the electrodes through hanger rods or through separate additional rods attached to the frame support means and which will extend through the precipitator roof.

In one embodiment, the present invention provides a swing hammer rapping system for dislodging particles from electrostatic precipitator electrodes that locates the hammers external of the gas chamber and the electrodes spaced therein, which comprises in combination, (a) a plurality of free-fall swing hammer means positioned above the roof of a gas stream chamber and above the tops of a plurality of vertically suspended electrode members which are, in turn, positioned in a spaced relationship across the width of such chamber, (b) power-operated shaft means and pin connection means thereon for holding said hammer means, (c) spaced rod means extending upwardly from the upper portions of the framing for the holding of such electrodes as are to be jarred and passing through the roof portion thereof, ,(d) strike pad means on each of said upwardly extending rod means for receiving blows from said swing hammer means, and (e) the positioning of said hammer and said shaft means with respect to said rod means from the electrode framing such that the free-fall of the swing hammers as they are rotated by the shaft means will effect periodic blows on the pad means and the connecting electrodes.

With regard to grounded electrode plates, provision may be made to have an extension rod from each set or row of collector plates and an accompanying swing hammer to periodically strike blows against the pad on each of the extension rods; however, typically there can be a grouping of rows of the electrode plates will be suspended from short cross beams, or other transverse support members, and an extension rod provided from at least one of the cross beams to receive the periodic blows from the swing hammer means. In connection with relatively short rows of collector plates, a single extension rod from a cross beam at one end of the rows of plates may suffice to effect suitable jarring and dust removal from the collector plates; however, where there are relatively long rows of plates then it may be advisable to have at least one extension rod from each of the supporting cross beams in order to provide adequate jarring to the plurality of suspended collector plates.

It is not intended to limit the present invention to any one form of framing or supporting system to hold the upper end portions of the plurality of longitudinally positioned electrode plates but generally, as heretofore noted, there can be the provision of suspended framing which, in turn, will hold and suspend a plurality of spaced apart parallel rows of collector plates that will have the spaced high voltage electrodes extending vertically therebetween. Also, a desirable construction and arrangement will provide for a spring suspension for the transverse framing or cross beams such that the jarring action from the periodic blows of the swing 3 hammer means will permit some yield or movement in a spring action jarring to the collector plates and a proper repositioning thereof following the jarring ac tion of the hammer blow. without having deformation to the rods or beams.

With respect to spaced high voltage discharge wires, there can be a plurality of upwardly extending rods from the framing for a certain grouping of discharge wires; however. where a single support hanger rod is used for a high voltage frame that is, in turn, holding a grouping of tensioned wires, there can be a striking pad provided with the top portion of such hanger rod above its insulated support means.

By having the power-operated shafts pin-connected to the arms of the swing hammer means in a zone above the roof of the precipitator unit, there can be ready access to all of these mechanical portions of the system as well as availability to effect adjustments in the intensity of the hammer blows. For example, there can be an adustable positioning arrangement for the rotating shaft means and/or adjustability with respect to the lengths of the crank arm means and the lengths of the arms for the swing hammer, In other words, means can be provided to readily increase or decrease arm lengths for each of the hammers and thus provide adjustability with respect to the intensity of the blow which will be exerted on each of the strike pads on the extension rods carrying to the collector plates or to the supporting frames for the collector plates. It is generally desirable to provide coverings over the shaft means and the swing hammer means and as has been provided in connection with certain electrostatic dust precipitator units. there may be the provision of a penthouse or other suitable covering over the entire precipitator unit whereby there may be the coverage of rectifiers and other electrical equipment in such units. There may also be the provision of pressurizing the interior of the covering means or penthouse structure so as to preclude the upward filtering of dust or particulates from the laden gas stream being passed through the unit. Pressurizing can be of particular advantage where there is a multiplicity of openings through the roof of the precipitator such as provided around the plurality of upwardly extending rods for effecting the jarring of the electrode plates.

The construction and arrangement of the improved rapper system, as well as further advantages obtained in the use thereof, will be further described in connection with the accompanying drawing and the following descriptive matter set forth in connection therewith.

FIG. I of the drawing is a diagrammatic partial sectional elevational view indicating means for effecting swing hammer blows to extension rods carrying through the roof portion of the precipitator unit down to a supporting frame member for a plurality of electrode particle collecting plates.

FIGv 2 of the drawing is an enlarged isometric view showing the end portions of a plurality of parallel and spaced apart rows of collector plates being suspended from a transverse beam which, in turn, is spring supported from the precipitator framing and has an upwardly extending rod means to receive blows from swing hammer means.

FIGS. 3(a), (b) and (c) indicate diagrammatically how a freefall swing hammer will be carried by the crank arm from a power-operated shaft to an upward substantially vertical position from which it will then fall by gravity to strike a pad means on the extension 4 rod which will be connective with the lower collector plate means of the precipitator.

FIG. 4 of the drawing is a sectional elevational view indicating diagrammatically how swing hammer blows may be provided to the top of an insulated rod for a high voltage frame in turn supporting a plurality of spaced high voltage discharge wires.

Referring now particularly to FIGS. 1 and 2 of the drawing, there is indicated a precipitator unit 1 having a gas inlet (or outlet) opening at 2 to provide for a substantially horizontal gas flow through the unit. Within the internal portion of the precipitator unit there is indicated a row of electrodes or collector plates 3 which are supported from a rod means 4 in turn having its end portion supported from a transverse channel shaped beam 5. In accordance with conventional precipitator design and operation, there will be a multiplicity of spaced high voltage wires (not shown in FIGS. 1 and 2) suspended in rows throughout the interior of the precipitator unit and in addition there will be a plurality of spaced and grounded electrodes arranged in parallel rows each side of the high voltage wires such that ionized particulates will be caused to collect at the electrodes and removed from the particle laden gas stream as it carries through the precipitator unit. Specifically, with respect to the embodiment shown in the slightly enlarged FIG. 2, there are a multiplicity of spaced rows of collector plates 3 and each row is indicated as being suspended from a suitable upper rod member 4 having an extended portion 4' carrying to the upper flange 6 of the transverse beam 5. There is also indicated the 'utilization of spaced pin members 7 along the top flange 6 of beam 5 so as to retain end portions 4 in a desired spaced relationship.

In a preferred construction and arrangement, as also indicated in FIG. 2, each transverse frame member or cross beam 5 is spring supported from a portion of the precipitator framing, such as a girder means 8. Specifically, there are indicated clip angles 9 from the side portion of girder 8 which will provide for a spring supporting of beam 5 by virtue of short upwardly extending rods 10 carrying upwardly through openings in the flange portion of clip angles 9 and through spring means 11 to nut and washer means at 12, or to other suitable cap means which will effect the spring suspension of the beam member 5. There is further indicated that an extension rod member 13, with its strike pad means 14, will be fixedly connected at its lower end portion to the cross beam 5 such that the jarring action from a swing hammer means will be carried directly to the beam member 5 and then from the latter to the suspended rows of collector plates 3.

As best shown in FIG. 1, each extension rod member 13 carries from the supporting beam member 5 through an opening in a roof or floor section 15 so as to be out of the gas stream path moving through the interior of the precipitator 1. There is also indicated the use of supporting framing 16 and cantilever support means 17 to hold a rotating shaft member 18 having crank arrn means 19 to operate swing hammer means 20. The latter as well as the shaft means will be positioned relative to the positioning of the various extension rod means 13 and their strike pads 14 such that each of the hammers will be aligned in a manner to strike the pad means 14 after the rotating shaft and crank arm means carry each swing hammer means past a vertical positioning to permit the free-fall blow to the extension rod and subsequently to the collector plates 3. In FIG. 1

there is also indicated diagrammatically the provision for motor means 21 to operate sprocket means at 22 and chain means 23 which will, in turn, operate the sprocket means 24 and the shaft means 18. For illustrative purposes, merely one row of extension rod means 13 and one shaft 18 have been indicated to operate hammer means such as 20; however, it will be obvious that a plurality of shaft and hammer means will be spaced across the roof of the precipitator unit to accommodate as many extension rods 13 as may be required to carry downwardly to the collector plates, or to the support framing for the collector plates, in order to effect the desired intensity of rapping to insure the dislodging of collected dust particles on the plates 3. As an alternative, there could be the upward extension of support rods and the placement of strike pad means on the upper ends thereof, in lieu of separate additional rods 13, and a substantially equivalent jarring action provided back to the collector electrodes from the swing hammer means.

A plurality of shafts, such as 18, can be operated from a single motor unit 21 and suitable sprocket means 22; however, additional motor units and pulley or sprocket arrangements may be utilized as required for any particular precipitator unit and, in general, the number of motors, shafts, extension rods, etc., will depend upon the overall size of the precipitator unit. Various types of shaft support framing can be utilized and it is not intended to limit such support framing to that which is shown in the drawing; however, preferably, the support framing for the hammer operating shafts will be of a type which will permit transverse and/or vertical adjustment such that there may be slight movements of the shaft positioning and thus provide adjustability to accommodate different crank arm lengths or different length arm portions for each of the swing hammer means in the event that it is desired to provide a different intensity blow to the extension rod members carrying to the collector plates.

As best shown in FIGS. 3(a), (b) and (0), each of the swing hammer means will be hingedly connected to crank arm means 19 by means of a pinned connection at 25 through a clevis end portion 26 on arm 20 for the hammer 20. Thus, in the operation of the swing hammer, the shaft 18 will be operated at a constant speed to carry crank arm 19 and pin means 25 through the rotation circle indicated by the dashed line 25 (also indicated to be turning clockwise) so that hammer 20 is also carried around in clockwise direction to reach a generally vertical position form which it will fall by gravity to effect the desired blow on strike pad means 14 and extension rod means 13. Specifically, in FIG. 3(a), there is shown the hammer means 20 being carried forwardly by virtue of the back of clevis 26 at its juncture with the end of arm portion 20 resting against the side of crank arm 19 such that there is an initial path for the hammer portion 20 following dashed line 27. Thus, as shown in FIG. 3(b), after crank arm 19 is moved on past an upward vertical position and down to the positioning indicated, then hammer 20 will have reached the generally vertical elevated positioning and be ready to go on past dead center and effect a freefall hammering operation as indicated in FIG. 3(c) of the drawing. In the latter Figure, it will be noted that crank arm means 19 has moved a few degrees further in a clockwise direction, along the circle 25 while at the same time hammer 20 has moved from the positioning of 3(b) along the path 27 to reach a strike pad 14 on 6 the upper end of an extension rod 13. Although not shown in the drawing, the continued clockwise movement of arm 19 will drag the hammer 20 from the top of pad 14 and continue its carrying operation such that it approaches the position of FIG. 3(a) and will, of course, continue on around to eventually again cause the hammer to fall and strike the pad 14. A similar type of swing hammer operation will be utilized in connection with each extension rod 13 from each set of suspended electrodes or collector plates 3. Typically, shaft rotations, crank arm locations, and shaft speeds will be regulated and controlled such that there is a predetermined time interval for effecting the hammer striking of each of the extension rods and each set of collector plates whereby all of the plates are not being struck and jarred at the same time. The motor means, the sprocket arrangements and/or gear box means therebetween, will preferably be designed and arranged such that adjustable speeds can be provided to the various shafts and the connecting swing hammer means for the entire system of the precipitator unit.

In FIG. 4 of the drawing there is shown diagrammatically that swing hammer means may also be used in connection with dislodging particles from the high voltage discharge wires of a precipitator. Specifically, there is indicated a plurality of spaced discharge wires 28 hanging from spaced support bars 29 which will be held by spaced beams 30, that will be transverse to the plurality of spaced bars 29. The beams 30 are, in turn, shown as being held by cross beam means at 31 and generally there will be two or more spaced beams 31, each with a hanger rod 32, to effect the support of the top framing system for a particular grouping of spaced high voltage wires 28. In view of the high voltage conditions, it is customary to have an insulated support arrangement for the hanger rods 32 such as an insulating cylinder 33 from the chamber roof or floor 15 to carry to a plate 34 in turn holding spring supports 35 and a rod holding plate 36. A threaded nut 37 is shown above the plate 36 to hold the rod 32 and, in turn, the high voltage wire support framing therebelow. In accordance with the present invention, an additional strike pad or plate 37 is, in turn, positioned over plate 36 by suitable support bars or rods 38 such that there is provision to jar the framing and hanging wires 28 from a swing hammer means 39 attached to a crank arm 40 and shaft 41.

There will generally be a swing hammer means above each insulated hanger rod means 32 above the roof or floor level 15 such that each rod for each high voltage electrode framing system will be periodically rapped and jarred to provide an efficient removal of collected particles on such electrodes. It should, however, be noted that in connection with the high voltage discharge framing and support system, in particular, there should be an insulating arrangement in the swing hammer connections or in the swing hammer operating means. For example, the shaft 41 will be provided with spaced insulating sections between the hammers and the drive means to the shaft. Various types of insulating means and methods for placing insulators can be used and it is not deemed necessary to show or describe such means in detail.

As an alternative to rapping the main hanger rods such as 32, there could be additional rods extending upwardly at dashed lines 42 at each end of beams 31. Such rods would have strike pad means on their upper end portions to accommodate suitably placed swing hammer means, such as 39. Such rods would also have suitable insulator means therearound at the roof level 15. In still another instance, rods such as 42 could be used as actual hanger rods, in lieu of 32, and there would be two support rods for each end of an upper framing arrangement at cross beams 31.

It is to be again pointed out that the hammer means, the hinge or pin connection means between the hammer and the crank arms, and the rotating shafts may have various types of constructions and arrangements and should not be limited to the particular diagrammatic embodiments shown in the present drawing. Also as heretofore noted, various types of shaft supporting means and sprocket and chain arrangements may be utilized within the scope of the present invention without being limited to the particular constructions being indicated diagrammatically in the present drawing. As a still further aspect, various means for supporting the collector plates to transverse beams or to other frame supporting means may well be utilized in the present invention and should not be limited to any one design. However, a preferred system will have spring supports for the electrodes. or for the framing means holding the multiplicity of electrodes, such that there is a resilient spring action for the jarring force carrying through from the hammer means to the extension rod means and to all of the electrodes which are to be subjected to rapping.

While the present high voltage discharge electrodes have been shown as wires, it is, of course, to be understood that rods, or bars, or special shapes may well be used for the discharge electrodes. Also, the collector electrodes may well have a shape different from the plates being shown in the present drawing.

l claim as my invention:

1. A swing hammer rapping system for dislodging collected particles from the electrodes of an electrostatic precipitator that locates the hammers external of the gas chamber, which comprises in combination,

a. a plurality of free-fall swing hammer means positioned above the roof of a gas stream chamber and above the tops of a multiplicity of vertically suspended electrodes which are, in turn, positioned in a spaced relationship across the width of such chamber,

b. power-operated shaft means and pin connection means thereon for holding said hammer means,

c. spaced rod means extending upwardly from the upper portions of framing for the holding of such electrodes that are to be jarred and passing through the roof portion of the gas chamber without contact therewith of said precipitator,

d. strike pad means on each of said upwardly extending rods for receiving vertical blows from said swing hammer means, and

e. the positioning of said hammer and said shaft means with respect to said rod means from the electrode framing such that the free-fall of the swing hammers as they are rotated by the shaft means will effect periodic vertical blows on the pad means and the connecting electrodes.

2. The swing hammer rapping system of claim 1 fur ther characterized in that a plurality of rows of collector plates are supported on transverse support beams and at least one extension rod extends upwardly from a transverse beam at one end of the collector plates to receive blows from said swing hammer means.

3. The swing hammer rapping system of claim 2 still further characterized in that at least one extension rod extends upwardly from each transverse beam supporting the opposite ends of the rows of collector plates.

4. The swing hammer rapping system of claim 2 still further characterized in that said transverse beams for supporting said rows of collector plates are in turn spring supported from framing for the electrostatic precipitator, whereby resilient spring action jarring is provided for the beams and the support collector plates.

5. The swing hammer rapping system of claim 4 further characterized in that spring supported hanger rods hold said transverse beams from the framing of said precipitator and upwardly extending portions of at least a portion of such hanger rods extend above the gas chamber roof and have strike pad means to serve as said upwardly extending rod means receive said periodic blows from the swing hammer means.

6. The swing hammer rapping system of claim 1 further characterized in that there is adjustability in the positioning of said poweroperated shaft means and for effecting the rate of rotation thereof, whereby there may be adjustability as to the rate of effecting hammer swing blows and adjustability as to lengths of arms used for said swing hammer means.

7. The swing hammer rapping system of claim 1 further characterized in that the high voltage discharge electrodes are suspended from cross bars which are supported by an upper, generally horizontal, framing means and such framing is, in turn, supported from upwardly extending hanger rods that are spring supported above insulator means, such rods are provided with strike pad means to serve as said upwardly extending rod means for receiving blows from said hammer means, and portions of the means operating the swing hammer means are insulated from the electrical precipitator framing to preclude any electrical energy carrying through such hammer operating means from said strike pad means on the rod means.

8. The swing hammer rapping system of claim 1 further characterized in that separate upwardly extending rods from a top framing support means for suspended, spaced apart, high voltage discharge electrodes as said rod means which extend through the roof of said gas chamber, said separate rods are provided with strike pad means for receiving the blows from the swing hammer means, and portions of the means for holding said swing hammer means are insulated from the electrical precipitator framing to preclude electrical energy carrying through the hammer operating means from said strike pads on the rod means.

9. The swing hammer rapping system of claim 1 further characterized in that housing means is provided over said swing hammer system above said electrostatic precipitator gas chamber, whereby there may be pressurizing within such housing means to preclude particulates flowing upwardly through openings in the roof portion of the precipitator from the gas stream passing therethrough.

Claims

1. A swing hammer rapping system for dislodging collected particles from the electrodes of an electrostatic precipitator that locates the hammers external of the gas chamber, which comprises in combination, a. a plurality of free-fall swing hammer means positioned above the roof of a gas stream chamber and above the tops of a multiplicity of vertically suspended electrodes which are, in turn, positioned in a spaced relationship across the width of such chamber, b. power-operated shaft means and pin connection means thereon for holding said hammer means, c. spaced rod means extending upwardly from the upper portions of framing for the holding of such electrodes that are to be jarred and passing through the roof portion of the gas chamber without contact therewith of said precipitator, d. strike pad means on each of said upwardly extending rods for receiving vertical blows from said swing hammer means, and e. the positioning of said hammer and said shaft means with respect to said rod means from the electrode framing such that the free-fall of the swing hammers as they are rotated by the shaft means will effect periodic vertical blows on the pad means and the connecting electrodes.

2. The swing hammer rapping system of claim 1 further characterized in that a plurality of rows of collector plates are supported on transverse support beams and at least one extension rod extends upwardly from a transverse beam at one end of the collector plates to receive blows from said swing hammer means.