US1319706A

US1319706A - Apparatus for the electrical treatment of gases

Info

Publication number: US1319706A
Authority: US
Publication date: 1919-10-28
Anticipated expiration: 1936-10-28

Description

'c. w. J. HEDBERG. APPARATUS FOR THE ELECTRICAL TREATMENT OF GASES.

APPLICQTION FILED FEB. 261 i918.

Patented Oct. 28, 1919.

izkluw emima,

TED STATES PATENT OFFICE.

CARL WM. J". HEDBERG, OF NEW BRITAIN, CONNECTICUT, ASSIGNOR TO RESEARCH CORPORATION, OF NEW YORK, N. Y.,

A CORPORATION or New YORK.

LIMSRYOU.

Specification of Letters Patent.

Patented Oct. 28, 1919.

Application filed February 26, 1918. Serial No. 219,305.

To all whom it may concern.

Be it known that I, CARL WILLIAM JULIUs Hnnnnne, a. citizen of the United States, residing at New Britain, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Apparatus for the Electrical Trcz ment of Gases, of which the following is a specification.

The present invention relates to apparatus for removing suspended particles from gases or gaseous mixtures by the application of high potential electric charges.

In apparatus of this character comprising principally discharge and collecting electrodes a field of intense electric stress is produced, through which the gases are passed. The suspended particles are charged by the discharge electrode and i'nigrate under the influence of this charge toward the collecting electrode.

It is customary to make the discharge electrode of a wire or other longitudinally extending conducting element and the collecting electrode in the form of a plate, box or cylindrical tube. The discharge electrode presents a small surface with the result that the electric field is highly concentrated and forms a zone of stress of great intensity, while near the collecting electrode,'on the other hand, since it presents a relatively large area, the intensity of the field is small. The theory on which the arrangement is based is that the particles suspended in the gases should be intensely charged near the discharge electrode to force them transversely of the gas stream toward the collecting electrode and that the collecting electrode in turn should not be able to neutralize this charge or even reverse it. It is the idea to make the migration substantially unidirectional and thereby prevent particles once forced out of the active zone from being returned to it.

Some particles drop, due to their own gravity, down through the inactive zone near the collecting electrode into a collecting chamber. Others agglomerate and in that condition fall through the inactive zone into the collecting chamber. Still others ,are carried along due to the velocity of the gas. The greater portion, however, of the particles are forced against the collecting electrode and collect thereon or adhere thereto forming a gradually increasing deposit.

Such deposit is detrimental to the operation of the apparatus and must be periodically removed.

It is the general object of the present invention to remove suspended particles from gases and a more particular ohjectfto keep the collecting electrodes clean while the particles are removed.

Another object is the removal of dust, fumes and other suspended particles from swiftly moving gases.

The apparatus embodying the invention, in order to carry out the objects mentioned, deviates in principle from the usual types above referred to in that the collecting electrode does not present a large surface, co extensive withthe discharge electrode, but has the form of transverse webs presenting circular edges toward the discharge electrode and concentric therewith.

The purpose and specific advantages of this construction will appear more clearly in connection with the accompanying drawings, in which Figure l is an elevation partly in section, and

Fig. 2 a transverse section on line 22 of Fig. 1.

In the drawings, 1 represents a box-like structure forming the treater chamber. The gases enter this chamber through the conduit 2, flow upwardly in the chamber and pass ofl' into the atmosphere or may be conducted to some particular place for use or further treatment. In the chamber 1 there are a plurality of transverse webs 3 arranged in tiers from bottom to top. These transverse webs 3 have a relatively large number of perforations t, equal in size and equally spaced, and the perforations of the different tie-rs are all in vertical alinement. T he webs are of electrical conducting material and constitute in their entirety a collecting electrode.

Through the vertically alined openings 4 extend longitudinally extending conductors such as fine wires 5 which form the discharge electrodes. These wires are supported by a frame 6 resting on insulators 7 on the. top

spacing frame 10 and weights 11 may be attached thereto to hold the wires taut. The

between the central or discharge electrode and the webs or collecting electrodes, charges are induced .upon the suspended particles or they receive charges from= the ionized gases. These charges move under the influence of the electric fields and take with them the suspended particles to which they are attached. The fields are strongest and the movement of particles is greatest between the discharge electrode and the orifice edges, but the particles do not come to rest in the intense parts of the fields, seeking rather the weak fields adjacent those portions of the webs which are at a distance from the orifices.

This characteristic may be explained in partby calling attention to the phenomenon commonly called electric wind. The molecules of the gases which have become ionized, and are called ions, and the suspended particles to which electric charges are attached, are propelled rapidly through the gases by the force of the electric field. The movement of these particles and molecules has an aspirating. effect upon adjacent gas molecules setting them in motion, the direction being from the strongest to the weakest part of the field. It is conceded that there are charges of both positive and negative sign present in the gases and they tend to move in opposite directions, but

- those which tend to move counter-current to the electric wind have to overcome considerable resistance and are probably swept back or neutralized, especially if these charges are endeavoring to take with them suspended articles. By making the central electro e of negative polarity the move-v ment of gases is set up by electrons and negative ions which have a higher velocity 1 than positive ions and the results described above are thenthe most pronounced and most satisfactory. In fact it is found that practically no particles get to thecentral electrode and settle upon it. In some instances it has been advantageous to have the orifice edges comparatively shar and the corresponding field strength ad acent. thereto correspondin ly great which tends to give a slight back-ionization and a resistance to the depositing of particles, but it is probably the momentum of the particles,

potential drop per unit of dielectric distance is considerably increased and thereby the electric stress or ionizing capacity.

The direct result is a general increase of the efiiciency of the treater. .This form of device is particularly adapted for the treatment of swiftly moving gases.

A distinct advantage gained is that by this arrangement the particles once precipitated are definitely removed from the gas stream. The zones intermediate the orifices 4 are outside the gas current and there is no force tending to bring them back into it.

It is further apparent from this arrangement that the current of dust laden gas as it passes through the apparatus is subjected to repeated changes in direction and velocity of gas flow. The velocity of the gas current is increased as it passes through the orifices and then is diminished as it expands into.

particles from the tre-ater, the transverse webs 3 are divided into a plurality of pivotally' mounted sections 16. The line of division between the separate sections lies substantially in the planes passing through the rows of discharge electrodes and the pivotal moyement takes place in planes centrally between the discharge electrodes. to which the sections 16 may be connected in any suitable manner, extend through the chamber 1 .and have bearing in opposite walls thereof. At one side these rods 17 extend beyond the outer surface of the wall so that suitable means may. be provided forturning them. In the particular instancecrank levers 18 are secured to the rods. At their outer ends these crank levers 18 are provided with slots 19. The crank levers 1.8 of each tier are inter onnected. by rods Rods 17,

essary to start the motor 30 joints comprising levers 25 and, bell or bars 20 having laterally projecting pins 21. These pins 21 extend into theslots 19 and are so spaced along rods 20 that all crank levers 18 have the same angular position. When the rods 20 are reciprocated, the cranks are simultaneously turned through an angle indicated by the relative -positions of the cranks in the two bottom rows in Fig. 1. By thus turning the cranks the sections 16 are turned from the position shown in the bottom row to that shown in the second row in Fig. 1, so that the deposit may drop down into a collecting chamber or hopper (not shown) where it may be removed.

To facilitate the separation of the deposit from the sections 16, provisions aremade for jarring or knocking them during their turning movement. As a convenient means I have shown bars or rods 22 mounted parallel to the pivotal rods 17 and positioned in the path of rotary movement of the sections 16, as indicated in Fig. 1, second row. The rods 20 may be mounted in bearings 23 \attached on the outside of the chamber 1. To operate all rods 20 simultaneously, they are interconnected by an arm 24 and toggle cranks 26 pivotally interconnected in a manner well understood; The arm 24 terminates in a slotted cross arm 27 engaged by the crank pin 28 on a crank driven by a motor 30 all as .is well understood. The arm 24 is supported for sliding movement in bearings 31 attached to the wall of the'cha mber 1.

As indicated, the sections 16 preferably contact along oblique planes for the purpose of alinement and mutual support.

The operation is apparent from the preceding description. When it is desired to rap the collecting electrodes, it is only necwithout first disconnecting the apparatus from the line.

In the foregoing an attempt has been made to merely 'outline the broad principles governing the invention. It is, of course, not necessary to move the orifice plates into alinement each time they are jarred. The translating mechanism may be suitably modified so that the orifice plates repeatedly strike the member 22 without each time returning to the alining position.

In practice the orifice plates may be placed closer together than shown in the drawing as is obvious. In fact, while I have shown all orifice plates as simultaneously operated for tilting movement, I contemplate the separate tilting of the different tiers commencing with the top tier and successively going down to the bottom tier.

I may also restrict the pivotal movement of the orifice plates to a relatively small angle, where the deposit is such that it may be easily removed from the plates.

While I have suggested a tilting of the disk 29 which may be plates for removing the deposit thereon, such tilting movement is not absolutely essential and provisions may be made for removing the deposit in other ways and by difi'erent means than by rotation.

I contemplate these and such other changes as may readily suggest themselves during the application of my invention to different conditions.

l Vhat is shown and described is merely for the purpose of illustration.

I claim t .1. In apparatus for the electric treatment of gases, a treater chamber, a collecting electrode consisting of a plurality of spaced electric-ally interconnected plates in said chamber, a plurality of orifices in each plate, each orifice in each plate being substantially in alinement with an orifice in each of the other plates and a discharge electrode extending through each space defined by alined orifices.

In apparatus for the electric treatment of gases, at treater chamber, a plurality of spaced plates in parallel arrangement constituting collecting electrodes, alined orifices in said plates to form a conduit for the gases, a discharge electrode extending through said conduit and means for rapping the plates.

3. In apparatusfor the electric treatment of gases, a collecting electrode comprising a treater chamber and a plurality of vertically Spaced electrically interconnected plates therein in parallel arrangement, alined orifices in said plates to form a conduit for the gases, a discharge electrode extending through the said conduit and means for removing deposit from the said plates.

4. In apparatus for the electric treatment of gases, at collecting electrode comprising a treater chamber and a plurality of vertically spaced plates therein in parallel arrangement, alined orifices in said plates to form a conduit for the gases, a discharge electrode extending through the said conduit and means acting on the said plates to remove deposit therefrom while the elec trodes are charged.

5. In apparatus for the electric treatment of gases, a collecting electrode comprising a treater chamber and a plurality of vertically spaced plates therein in parallel arrangement, alined orifices in said plates to form a tonduit for the gases, a discharge electrode extending into for tilting at will the said plates.

6. In apparatus for the electric treatment of gases, a collecting electrode comprising a treater chamber and a plurality of vertithe said conduit and means;

rangement, alined orifices in said plates to' form a conduit for the gases, a discharge electrode extending, into the said conduit, means for tilting at will the said plates and means for rapping said plates during the tilting movement.

7. In apparatus for the electric treatment of gases, a collecting electrode comprising a treater chamber and a plurality of vertically spaced plates pivotally mounted therein, alined orifices in said plates to form a conduit for the gases, a discharge electrode extending into the said conduit, means for turning the plates about their pivots and means for rapping them during such turning movement. I

8. In apparatus for the electric treatment of gases, at collecting electrode comprising a treater chamber and a plurality of'electrically interconnected vertically spaced plates therein, a plurality of orifices in each plate, each orifice in each plate being substantially in alinement With an orifice in each of the other plates, a discharge elect-rode extending into each space defined by alined orifices and means forremoving deposit from the said plates.

9. In apparatus for the electric treatment of gases, a collecting electrode comprising a treater chamber and plurality of verticallv spaced plates therein, a plurality of orifices in each plate, each orifice in each plate being substantially in alinement with an orifice in each of the other plates, a dischar e electrode extending into each space defined by alined orifices and means acting onthe said plates to remove deposit theretransversely thereof,

from while the electrodes are charged.

10. In apparatus for the electric treatment of gases, a collecting electrode comprising a treater chamber and a partition said partition being composed'of a plurality of pivotally mounted sections constructed and arranged to define a plurality of orifices, a discharge electrode extending into each orifice and means for turning each section about its pivot.

11. In apparatus for the electric treatment of gases, a collecting electrode comprising a treater chamber and a partition transversely thereof, said partition being composed of a plurality of pivotally mounted sections constructed and arranged to define a plurality of orifices, a discharge electrode extending into each orifice, means for turning each section about its pivot and means for rapping it during such turning movement.

12. In apparatus for the electric treatment of gases, a collecting electrode comprising a treater chamber and a partition transversely thereof, said partition being composed of a plurality of pivotally mounted sections constructed and arranged to define a plurality of orifices, a discharge electrode extending into each orifice, means for simultaneously turning said sections about their pivots.

13. In apparatus for the electric treatment of gases, a collecting electrode comprising a treater chamber and a partition transversely thereof, said partition being composed of a v plurality of pivotally mounted sections constructed and arranged to define a plurality of orifices, a discharge electrode extending into each orifice,means for simultaneously turning said sections about their pivots and means for rapping the sections during such turning movement.

In testimony whereof I afiix my signature in presence of two witnesses.

CARL WM. J. HEDBERG.

Witnesses:

ROBERT B. On, MARGARET E. OTT.