US1252104A - Art of electrical precipitation of particles from fluid streams. - Google Patents

Description

C. W. GIRVIN.

ART OF ELECTRICAL PRECIPITATION 0F PARTICLES FROM FLUID STREAMS.

APPLICATION FILED MAR- 22. 1917.

1,252,104. I Patented 'Jan. 1, 1918,.

2 SHEETS-SHEET l.

C. WLGIRVIN. ART OF ELECTRICAL PRECIPITATIDN 0F PARTICLES FROM FLUID STREAMS.

APPLICATION FILED MAR- 22. I911- Patented Jan. 1, 1918.

2 SHEETS-SHEET 2- l memom I WM) UNITED sT-Atr s PATENT OFFICE,-

CHABLESW. GIBVIN, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOB 0F ONE-TENTH T0 VALENTINE G. SCOTT, 0F PHILADELPHIA, PENNSYLVANIA, AND ONE-TENTH TO HORACE G. SEI'IZ, 01'! NEW YORK, N. Y.

ART OF ELECTRICAL PRECIPITATION OF PARTICLES-FROM FLUID STBE AMS.

Specification at Letters Patent. Patented Jan, 1, 1918.

Application filed March 22, 1917. Serial No. 156,565.

To all whom it may concern:

Be it knownthat I, CHARLES W. GIRVIN, acitizen of the United States, residing at Philadelphia, in the county of Philadelphla and State of Pennsylvania, have invented certain new and useful Improvements in the Art of Electrical Precipitation of Particles from Fluid Streams, of which the following is a specification.

My present invention relates to the art of electrical precipitation of particles from fluid streams.

Practice of this art'involves the creation of anionization field or fields in the flow path of a stream and collection of the depositson the stream boundary or bounda connected to the source, the stream passing a in the direction of length of the pipe and through the field formed between the pipe and Wire. A preferred form of apparatus ings, certain difiiculties appear.

stance, one of the inherent results of the preemploys the corona type of discharge in producing the field, although other types have also been employed;

In practising this art under prior teach- For incipitation by a field of this character is. that while deposits are collected on the stream boundary, such deposits will adhere thereto during activity of the field with the result that the deposits build up and decrease the distance between the electrodes to a point where disruptive discharges must and are formed across the field, practically shortcircuiting the apparatus while the are remains; this renders it difiicult to operate the;

this-difficulty, the efficiency is reduced unless therate of liow of the stream be greatly reduced, thus materially decreasing the ca pacity of the apparatus. While such change may increase the time between successive dis ruptive discharges they are not thereby avoided.

It has been contemplated to meet this by employing the disruptive discharge 'to dis lodge the deposits, but this necessarily involvcs' meetingv the problem of preventing damage to appara us by such discharges. Various other soluiions have been contemplated, but, so far as I am aware,'each advantage gained isat the sacrifice of some other advantageous feature, so thatthe combined result is approximately the same high cleaning efiiciency with low capacity, or

the reverse. It is well known that a field of this type will produce the deposits and clean the stream, but the principal problemis apparently to clean the cleaner. p

This problem of cleaning the cleaner is met in thepresent invention by not attempting to provide any cleaning action in the active portion of the field, but produce the deposit collection within theactive portion of the field and shift the collecting surface into an inactive portion of the field Where the deposits are removed,v thus permitting such'building-up of collected deposits. but

removing the collecting surface before the building-up action has reached a stage where the disruptive-discharge conditions are present. Obviously complete absence of disruptive discharge formations may notice providedservice conditions may provide an excess of precipitated deposits under abnormal conditions-but such discharge formatiolns become the exception instead of the ru e. v

' A preferred form of apparatus for carrying out the general principles of the invention is to employ a rotatable collecting electrode withastationary active electrode, the two electrodes being relatively formed as to provide active and inactive portions of the ionization or electric field. By mounting a deposit-removing device in such inactive portion, the deposits collected in the active portion ofthe field are brought to the re" moving device and the collecting electrode.

more or less cleaned. Obviously, the else trode may be movable in directions other than rotatable, and it is to be understood that the invention contemplates the various ways in which the collecting electrode may be shifted between active and inactive portions of the field.

To these and other ends, therefore, the nature of which will be readily understood as the invention is hereinafter disclosed, said invention consists in the improved methods of deposit precipitation and removal and the construction and combinatlon of parts for carrying such methods 1nto etl'ect, as hereinafter more fully descr bed, illustrated in the accompanying drawings, and more particularly pointed out in the appended claims. r

1n the accompanymg drawings, 1n which similar reference characters indicate simllar parts in each of the V1BWS,-.

Figure 1 is a central vertical sectional view taken through an apparatus embodying the general principles of myinventlon, the structure forming one embodiment in which the general prmciples may be made serviceable.

Fig. 2 is a cross-sectional view w1th parts broken away.

Fig. 3 is a detail sectional view taken on line 33 of Fig. 2.

In the present embodiment, the field is shown as annular, and may be considered either as a single or a double field, dependent on whether the active electrode is in the form of a solid or skeleton structure. In either case the collecting electrode system is in the form of two concentrically arranged cylinders 10 and 11 between'which is located the active electrode 12 which, in the form shown is in the form of a support 12-solid or skeletonized as may be preferred--carry1ng a plurality of edgeforming members 12 suitably spaced apart and extending in planes which intersect the axes of the cylinders. The drawings show the members as extending in horizontal planes, but it is obvious that this may be' varied to a, more or less extent, as by having their directions of length more or less in clined to the horizontal. Members 12 in the form shown, are preferably on opposite sides of the support, cooperating with the opposing collecting electrode faces of cylinders 10 and 11.

As shown in Fig. 2, members 12 do not complete the circle although the electrode is of a form concentric to cylinders 10 and 11. A gap is thus formed in the circle, which gap produces an inactive portion of the general ionization field the active portion of which lies between members 12 and the opposing faces of the cylinders 10 and 11.

Electrode .12 is supported in suitable manner, as by a supporting member 12" com nected to the electrode by a spider structure 12, a suitable portion of the electrode system being connected to a source of high potential (not shown). It is to be understood, of course, that the parts will be suitably insulated.

The collecting electrode system (cylinders 10 and 11) is mounted on a turn-table structure 13 of suitable configuration and supported on rollers 14 properly located to permit a rotative movement to the turntable. Such movement may be provided in any suitable manner, as by connecting one of the rollers to a rotatable shaft 15, the weight of the turntable'and the parts carried thereby tending to produce sufiicient friction to drive the turntable. Obviously, other ways of rotating the turntable or cylinders may be employed.

As shown,.the turntable is arranged to close the interior .ofcylinder 10- from the flowing stream, while that portion of the turntable leading to the space between the cylinders may be more or less spider-like in form (Fig. 2) to permit the stream-entering from belowto pass into such space.

16 designates a casing within which the structure is located, the casing having an entrance 16'- and a discharge 16 Mounted in the inactive gap of the field is a suitable deposit-removing device. In the drawings th1s is shown as a scraper 17 which has its advance edges in contact with or in juxtaposition to the deposit-collecting faces of the cylinders. The scraper may be of suitable cross-sectional contour, that shown being semi-circular within the inactive zone and forming a ready passage for the removed deposits which drop to the bottom of the scraper on to a suitable trapdoor 17 which permits passage of the deposits into a collecting chamber 18 which is also preferably closed by a trap-door 18.

To prevent as far as possible direct entry of the stream into the inactive space or gap of the field, I preferably employ abaflie 17 at the lower end of the scraper and a baflielike structure 17 at the top of the scraper, baflle 17 tending to direct the entering stream away from the position of the scraper, bafile 17 tending to force any portion of the stream contents which may have shifted toward the scraper away'from the space. In other Words, the two bafiies tend to close the opposite ends of the space immediately in front of the scraper portion so as to tend to reduce the flow or velocity of any stream contents therein, thus tending to decrease the quantity of such contents which would pass through the inactive portion of the field.

As will be understood scraper l7 is more or less illustrative. Other forms of devices, as for instance, brushes, may be employed.

Members 12 each act as an active sleep efficiency and incidentally permitting introde, thus forming a plurality of ionization zones through which the stream passes while traversing the apparatus. Hence, the stream is subjected to maximum ion1zat1on action and the particles 'or molecules Will be carried on to the collecting electrodes 10 and 11 in the usual manner. However, the collectin faces of the cylinders are rotatable so that uring rotation the active portions of the surfaces will pass from the active portions of the field into the inactive por tion formed by the ap in the active electrode. and in which t e strain lines are absent or materially less effective. The depositremoving device is reached and the relative movement between collecting surfaces and the device causes the deposits to be removed, the surfaces again entering the active field portion and receiving new deposits.

As will be understood, the active portion of the field remains constant although the collecting surfaces are shifted between the active and inactive portions of the field. Hence the stream flow may be constant with the rate based on the capacity of the field to remove the deposits under normal opera tion, the deposit-removal problem being practically eliminated. In addition, the potential may be maintained close to the critical break-down voltage, thus increasing the crease in rate of stream flow, it being understood that the speed of rotation of the collecting electrodes may be controlled so as to practically insure that the amount of de posits will not reach a depth suificient to cause the disruptive discharge action excepting possibly under abnormal conditions. And in meeting these conditions the fact that the surface is constantly changing position within the active portion of the field, and the presence of a plurality of ionization zones through which the stream passes, tends to prevent formation of built-up deposits of large magnitude at isolated points. The scraper may be in actual contact with the collecting surfaces, thus cleaning them more or less thoroughly. However, this is not essential since a slight spacing will be effective, the presence of a small deposit on the surfaces reentering the active portion of the field oflering no material objection.

While I have shown but one field structure, it will be readily understood that by the addition of another cylinder concentric with those shown together with an additional active electrode within the space thus formed, an additional field may be provided, the cylinder being mounted on the turntable and the active electrode connected in the active electrode system. And such additions may be duplicated as desired, thus meeting the problem of capacity, since each additional field increases the .amount of gas, etc., which may pass the structure. It will be understood of course, that each field would have its individual removal device.

It will be obvious that the apparatus will operate with current of any of the wellknown types, as for instance, pulsating, oscillating, or the continuous current type, the question of the more or less adherence of deposits bein practically eliminated.

While I ave shown the gap of the active electrode as extending in a vertical plane, it will be understood that this may be varied to meet operating conditions, the deposit-removal device being arranged accordingly. For instance, it may be arranged more or less inclined to the vertical, in which case a baffle may project from the rear of the scraper to direct the adjacent portion of the stream into an active portion of the field.

The terms fluid used herein is intended to include streams of either liquid or gaseous .solid matter, such, for instance, as solid streams of powdered material.

While I have herein shown and described one embodiment for carrying out the general principles of my invention, it will be readily understood that the exigencies of installation and use and the character of work to be performed may require various changes and modifications in the construction and arrangement of parts, and I desire to be understood as reserving the right to make any and all such changes or modifications as may be required or deemed desirable in so far as the same may fall within the spirit and scope of the broad invention disclosed, as expressed in the accompanying claims.

Having thus described my invention, what I claim as new is:

1. In the art of electrical precipitation from flowing fluid streams and in which deposits are collected on a stream boundary, the method of removing such deposits which consists in establishing a' permanently inactive zone in the electric field, shifting-the deposit-laden boundary to such zone, and removing the deposits from the boundary while the latter is within the zone.

2. In the art of electrical precipitation from flowing fluid streams and in which deposits are collected on a stream boundary, the method of removing such deposits which consists in establishing a permanently inactive zone in the electric field, moving the deposit-laden boundary laterally of the direction of stream flow into such zone, and removing the deposits from the boundary while the latter is within the zone.

3. The method of collecting and removing particles or molecules from a flowing fluid stream, which consists in establishing deposit material on a stream boundar within an active portion of the field, shiftlng the deposit-laden boundary between the active and inactive field portions, and removing the deposits from the boundary while in the inactive portion.

4. In the art of electrical precipitation from fluid streams, opposing electrode systerns adapted to produce an electric field having permanently-located active and inactive portions, means for moving the systems relatively to each other to bring a depositcollccting face into an inactive portion of the field, and means for removing deposits while in such inactive portion.

5. In the art of electrical precipitation from fluid streams, 0 posing electrode systems adapted to pro uce an electric field having permanentlydocated active and inactive portions, means for moving the collecting electrode system between the active and inactive portions, and means for removing the deposits while in theinactive portion.

6. In the art of electrical precipitation from fluid streams, opposing electrode systom adapted to produce an electric field havmg permanently-located active and inactive portions, means for rotating the collecting electrode system on its axis to shift a deposit-collecting face between such field port1ons, and means active within such inactive portion for removing the deposits from the face.

7. In the art of electrical precipitation from fluid streams, a rotatable tubular collecting electrode, an active electrode extending concentrically and formed to pro- 1 duce permanently-located active and inac tive portions of an electric field on a cross section on the collecting electrode, and means within the inactive portion of the field and rendered active by electrode rotalZlOIl for removing the deposits within such lnactlve portlon.

In testimony whereof I have aflixed my signature in the presence of two witnesses. CHARLES W. GIRVIN. Witnesses:

-V. G. Soo'rr, FRANCIS D. MAHoNn.

It is hereby certified that in Letters Patent No. 1,252,104, granted January 1, 1918, upon the application of Charles W. Girvin, of Philadelphia, Pennsylvania, for an improvement in The Art of Electrical Precipitation of Particles from Fluid Strearns," an error appears in the printed specification requiring correction as follows: Page 4, line 40, claim 7, for the word on read of; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office. 1

Signed and sealed this 12th day of February, A. 0., 1918.

.1. T. NEWTON,

L'omm-issimurr of Patents.

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