US2123464A - Electrode rapping - Google Patents

Description

July 12,1938. H. c. ENGELMAN 2,123,464

ELECTRODE RA'PPING Filed Aug. 28,1;[936 5 Sheets-Sheet 1 FI I3. E-

I I n I la a' d I 1A- l b\ if* E July 12, 1938. H. C. ENGELMAN 2,123,464

ELECTRODE RAPPING Filed Aug. 28, 1936 3 shegts-Sheet 2 "July 12, 1938. i H. c. ENGELMAN 2,123,454

ELECTRODE RAPPING Filed Aug. 28, 1936 3 Sheets-Sheet 3 FI E. E. 54

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93 92 sl' M e IIIIl Patented July 12,1938 y UNITED STATES ELEGTRODE RAPPING Herman C. Engelman, Oakwood Heights, N. Y., assignor to Research Corporation, New York, N. Y., a.' corporation of New York Application August 28, 1936, Serial No. 98,4119

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This invention relates `to electrodes for apparatus commonly referred to as electricalprecipitatorsand utilized for removing suspended particles V.from fluids. It is particularly directed at improvements in the `suspending and jarring of electrodes to bring about the dislodgement of the .material'that is electrically deposited on the surfaces of the electrodes, l

It is` common practice at the present time, where it is desirable to remove the deposits in dry condition, to pass scraping means across the surfaces upon which material has been deposited, or to rap the electrodes by'strilring them with hammers or similar jarring means with 5 manually or mechanically operated mechanisms,

or to lift them a short distance and thenV let them drop upon suitable anvils.

Scrapers that operate satisfactorily are coinplicated and expensive and usually necessitate shutting oi the power before they can be' operated. Where rappers have been used it has been customary to have them directed at one or two points on the frame of the electrode where it is structurally able to sustain repeated shocks. But the vibrations imparted at these local positions are seldom severe enough to produce movement over the entire surface of the stiened electrode. Most electrodes are made up of several members of different weight and shape and nodes of little movement with relation to"vibrations set up at distant points commonly exist. At such nodes the removal of the deposit is not satisfactory. t

It is an object of the present invention to provide means for-imparting vibrations to an electrode or electrode assembly in such manner that several trains of effective vibrationsfwill proceed over the surface of the electrode from several points thus eliminating vthe possibility of a node exisiting at any point on the electrode throughout the rapping cycle.

Another object of the invention is to provide a non-rigid and preferably flexible support for an electrode so that the electrode can be readily moved, rapped and vibrated in a manner con'- ducive to the removal of material clinging thereto.

Still another object of the invention is to pro- 0 vide an improved mechanism for imparting movement -to an electrode so that especially effective jarring is furnished for removal of de posits from the surface ofthe electrode.

The manner of realizing -the above mentioned and further objects oi' the invention is set forth in the description that follows, reference being `had to the appended drawings in which:

Fig. 1 shows a plate type collecting electrode, in side elevation, supported in accordance with the invention; 5

Fig. 2 is a plan view of the electrode shown in Fig. 1;

Fig. 3 shows a group of pipe collecting electrodes, in side elevation, arranged to ,be shaken in accordance with the invention; '10

Fig. 4 shows, in a horizontal section taken along d--d of Fig. 3, the electrodes and supporting means shown in Fig. 3; s

Fig. 5 is an end elevational view of the assembly shown in Fig. 3;

Fig. 6 is a side elevational view of an assembly comprising discharge electrodes, a support-v ing frame, and means for supporting and jarring the electrodes in accordance with the invention; Figs.- 7 and 8 are diagrammatical views of the assembly shown in Fig. 6 to illustrate the utilization of the forces that jar the assembly;

Figs. 9 and 10 are fragmentary views in side elevation and plan, respectively, of an alternate suspension for the assembly shown in Fig. 6; and

Figs. 11 and 12 are fragmentary views in side elevation and plan, respectively of a further suspension for the assembly shown in Fig. 6.

Referring to Figs. 1 and 2, el is the general identifying symbol of the electrode assembly comprising plate 2, reinforcing strip 3 and framing members t, 5, 6 andl'l. Electrode assembly i is located in an enclosure through which gas passes while being'v electrically cleaned, the enclosure being indicated in part in Fig. 1 by side plates i4, end plate i3 with exit (or entrance) opening 23. Structural members 9,12, l5, I6, 24, 25 and 26 reinforce the enclosure and furnish supports for the hopper, indicated by 21, and for the electrodes, and rapping means as will be explained more in particular later. Electrode assembly l is shown attached to supporting or shaking members at four points. Depending member 8, preferably a flexible strap, is attached to member 5 by fastening Il and to supporting member 9 by fastening I0. Member 8 sustains `most of thel weight of assembly I and, because of its fleizibility and because the point of attachment, at member Il is well down the side of the frame-usually from one-fourth to one-half of the1ength of the frame, member s sets up little resistance to movements of the assembly. 'I'he assemblyis also-guided and given further support by spring member I1 attached sembly. Another spring member 28 is fastened` to the electrode assembly by screws 29 and to structural member '25 by fastening 30. Member 3l is a bumper attached at one end to member 25 by screw 32 and free at the other end where it contacts anvil 34 on member 5 as anvil 34 approaches complementary anvil member 33 and thereby cushions the jar that would otherwise be imparted to the structural members of the enclosure if unyielding members 5 and 25 hit together strongly through members 33 and 34.

Other anvil means are provided in complementary members 35 and 36, the former being attached to frame member 5 of the electrode and the latter to structural member 24 of the precipitator proper. These members terminate the movement of the electrode at this point but also act as a fulcrum about which the electiode may turn in the plane of its maximumA surface. The face of one or both anvils is curved to admit more readily such turning movement.

A strap 31 is fastened to frame member'4 by bolts 38 and clip angles 39, the latter being preferably welded to member 4, and the strap is fastened by bolts 40 to a yoke 50 comprising angle pieces 4|, bolts 42, cushioning pad 43, pad supporting strap 44 `and nuts 45. A crank 48 with vise end 41 supports and moves a at sided rodl 46 which projects through yoke 50 and exerts a pushing force against pad 43 when crank 48 is swung by shaft 49 upon which it is mounted. Shaft 49 projects through wall I4 and rotates in bearing 5I. Rotation is brought about by the energization of solenoid 54 which pulls upwards on plunger 53 and crank 52. Energization of solenoid -54 may be ac- .complished by manual control but, preferably,

an automatic relay and Vtime control means of commercially available type indicated by symbol y'ro R is used. Control R. is operated by a local electric circuit c, d, and control R, in turn, controls the flow of Vcurrent from power source a, b,` through leads a', b', and a", b" to solenoid 54.-

For simplicity, only one electrode has been indicated as being rapped by bar 46 through the energization of solenoid 54. In practice, several electrodes are rapped by a single solenoid and the energization of as many as eight solenoids may be controlled by a single time control and relay.-

The embodiment of the invention illustrated in Figs. 1 and 2 operates as follows. Assuming that observations have indicated that the electrodes ,timed that after the current is discontinued there is a small travel of the parts mentioned and the iinal position of electrode I at clip angle 39 is, for example, one half inch away from its normal position. Following the movement of the electrode assembly just described and the de-energization of actuating means 54, the assembly swings in the opposite direction, due partly to the force of gravity and partly tothe tension in spring 28,

and anvil members 35 and 36 strike together. The bottom of the assembly continues to move, be

cause of inertia and the continued tension in spring 28, and turns about member 36 as a fuicrum. Almost immediately after the contact of members 35 and 36, member 33, the free end of spring 3i and member 34 strike together, the impact being cushioned somewhat by spring 3l. Simultaneous with, or immediately after, the impact at anvil 34 the top end of assembly I swings over and member 4 strikes against stop or anvil` member I9 and there is usually sufficient rebound from this impact to cause members 2I and 22 to strike together.

It iseimpossible to anticipate exactly the nature 'and amplitude of the movements set up but it is possible to vary the movements somewhat by changing the characteristics of springs 28 and I1, changing the length of member 8. the position of member I9, and the movement of strap 31. But while the motions may differ in degree, the overall results of suspending the electrode in nonrigid manner and imparting jarring impacts to it at a plurality of separated points are very satisfactory. Portions of the surface which do not receive vibrations from an impact at one point vibrate when other points are struck.

In Figs. 3, 4 and 5, pipes `60 serve as collecting electrodes in an electrical precipitator with axially positioned wires 6I functioning as discharge velectrodes. V`Each pipe is separately suspended by flexible, or non-rigidly fastened, straps 62 to a common supporting member 63, the straps 62 being fastened to the outside surface of the respective pipes 60 by tap bolts 64, or other suitable means, at positions 'about one third down the side of the pipes. Along the sid'e of the pipes near the bottom a common member 61 is fastened in a horizontal position, four pipes being shown connected together by such a member in Fig. 4. A strap 31' is attached to member 61, preferably at the mid position, and a bar 46 comprised in actuating mechanism similar to that described in connection withFig. 1, is for exerting a pull on strap 31 and initiating the movements that result in jarring the pipes. Anvils 33', 13 and 14 are fastened to each pipe and strike against restraining members 34', I9' and 63 respectively. A member 69 fastened to the outside of each pipe at approximately the mid point oi' its length contacts restraining member 68 and permits rocking of the pipe at this point. The ends of member 69 project out from the pipe and have holes in them through which guide pins 10 project. The pins 10 are only necessary if straps 62 and 31' and spring 28' are so yieldable that they do not maintain pipes 66 in proper positionv with regard to discharge electrodes 6I. To permit motion of the upper endof the pipes, the opening in header plate 65 is made larger than the pipe and the an-v nular space is closed with a flexible sheet 66 for instance, of canvas, or of asbestos.

The pipes shown in Figs. 3, 4 and 5 are jarred in much the same way as is the plate in Figs. 1 and 2. Referring to Fig. 5, the pipes 60 are pulled over out of their normal position by strap 31' and permitted to swing back,the voltage across the electrodes being preferably lowered during rapping. Members 68 and 69 strike together and at almost the same time members 33 and 34 strike together, the jar being tempered, if advisable, Aby a cushioning spring 3|. There is then a reaction that permits the top of the pipe to swing over so that pad 14 strikes member 63 followed usually by rebounds that alternately cause anvil pad 13 to strike restraining member I9 Vand pad 14 to strike structural member 63.

me discharge electrode assembly identified by numeral Ril in Fig. 6 comprisesa frame Bl with di. In the operation of electrical precipitators,

the Adischarge electrodes are usually maintained at high potential above ground. All members in contact with assembly B must, therefore, bev insulated from the grounded shell and the collecting electrodes comprising the precipitator of which assembly 80 is a part. To fulll this requirement, the bearings supporting the cam shaft which revolves cam 8l are `mounted on insulators '89 and restraining member 88 is mounted on insulators lid, a fragmentary portion of one of. each of these insulators being shown in Fig. 6.

Where it is desired to save head room, supporting structure til can be lowered by using the construction shown in Figs. 9 and 10. In this construction, member ill of frame `di is made up of two pieces tia and tlb joined by a' structurally strong sleeve ,92 with a hole in the bottom to iet dust fall through. Bearings held in the sides of pocket lit near the bottom thereof support pin @t to which link i513 is fastened and about which it may rotate.

In the form of suspension shown in Figs. l1 and 12, as in those shown in Figs. 6, 9 and 10, the electrode member is supported for pivotal movement about a movable pivot point symmetrically I positioned with respect to the electrode.

In this construction the top member-ti of the electrode frame has fastened thereto a member d5, bent at right angles at its upper end to form a bearing for roller @t which runs in curved track lil supported directlyl upon the roof dii oi.' the precipitator. The electrode is displaced from its normal position by means of double cam lit.

The manner vin which the invention as embodied electrode frame proper hangs vertically and the force acting upon it below pin dit is that oi gravity represented by arrow B. Now when the high point of cam ii'l. slips oi pad db, the 4iorces are no longer in equilibrium and the unbalanced horizontal pull on pin @t represented by b lcauses the top end of the frame to move quickly towards cam ti and hit strongly the bottom surface of the cam. The bottom end of the frame, because of inertia, does not move over simultaneously with the top end with the result that the center of gravity of the mass making up the electrode 1 assembly is now off 'center with regard to a perpendicular line passing through point of suspens101193 and integrated forces with a horizontal component represented by/ e in diagram C pull the bottom of the frame over and cause it to' strike stop 83. In fact, a set of. jerky, oscillatory, movements are set up `which cause the frame -to strike first at di! and then at 88.

The support shown in Figs. 11 and 12 operates The force.

in the same manner as that described for Figs. 6, 9 and 10, except that the pivot point ofthe electrode suspension moves along curved track 9i when the electrode is moved to one side by a cam or other means. The resulting forces may be represented bydiagrams similar to Figs. 7 and 8 and a similar series of jerky, oscillatory motions Will be set up.

It will be seen that a commoncharacteristic of y the electrode 'supporting and rapping devices of "the invention ls that the electrodes are supported so as to provide for an essentially gyratory motion in the plane oi' vibration as .iistinguishedl from a translatory or simple oscillatory motion of the devices ofl the prior art and that this gyratory motion in cooperation with striking members or anvils results in a highly eective jarring oi the electrodes at a plurality oi points. The term gyratory in the specication and claims is intended to dene simultaneous curvilinear motion about at least two separate points.

I claim: I

1. In an electrical precipitator, an electrode. means suspending said electrode for gyratory motion, anvil members positioned adjacent said electrode, at least one of said anvil members providing a iulcrum about which the electrode may cillate when in contact therewith, and means for displacing said electrode from its normal position.

2. In an electrical precipitator, an electrode, means suspending said electrode for gyratory motion, anvil members positioned adjacent said elcc' trode, means for displacing said electrode from its normal position, and releasing the electrode in its displaced position.

3. In an electrical 'precipitaton an electrode, means suspending said electrode for gyratory motion vin a. vertical plane, anvil members posi-` tioned adjacent said electrode, means for displacing said electrode from its normal position and for releasing the electrode in its displaced n position.

4. In an electrical precipitator, an electrode assembly comprising an electrode, means suspending said electrode for gyratory motion, means for displacing said electrode and for releasing the electrode in its displaced position and anvil members positioned adjacent said electrode to provide a plurality of successive blows at dilierent points on said electrode.

5. In an electrical precipitator, an electrode assembly comprising an electrode, means suspending said electrode for gyratory motion, means for displacing said electrode and for releasing the electrode in its displaced position and anvil members positioned adjacent said electrode to provide a plurality of successive blows at diierent points on said electrode at least one of said anvil members being adjustable in position with respect to said electrode.

6. In an electrical preciptator, an electrode yassemizvly comprising an electrode, resilient means suspending said electrode for gyratory motion, means ior displacing said electrode and for releasing the electrode in its displaced position and anvil members positioned adjacent said electrode to provide a plurality of successive blows at different points on said electrode.

7. In an electrical precipitator, an electrode, resilient members unsymmetrically attached to 'said electrode for positioning the same, anvil members positioned adjacent said electrode, and means for displacing said electrode from its normal position.

a supporting element and attached to said electrode at a point outside the vertical axis passing through the center of gravity of 4said electrode,`

anvil members positioned adjacent said electrode. means for displacing said electrode from its normal position and for releasing it in its displaced position.

9. A method of cleaning the electrodes oi.' an electrical precipitator which comprises suspending an electrode for gyratory motion in a vertical plane and subjecting it to a succession of blows at at least two diierent points on said electrode.

10. A method of cleaning the electrodes of an electrical precipitator which comprises resiliently suspending an electrode in a predetermined po-v sition and subjecting it to a succession of blows at at least two different points on said electrode.

11. In an electrical precipitator, an electrode,`

means suspending said electrode for gyratory motion, anvil members positioned adjacent said electrode, and solenoid-operated means for displacing said electrode from its normal position. 12. In an electrical precipitator, an electrode, means suspending said electrode for gyratory motion, anvil members positioned adjacent said electrode, and solenoid-operated means for intermittently subjecting said electrode to a blow and for displacing it from its normal position.

HERMAN C.'ENGELMAN.

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