US1064984A - Apparatus for trapping particles in suspension in gas-currents. - Google Patents

Description

T. E. MURRAY & GQB. GRADY.

APPARATUS FOR TRAPPING PARTICLES IN SUSPENSION IN GAS GURRENTS.

APPLIOATION FILED JAN. 9, 1913.

Patented June 17, 1913.

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THOMAS E. MURRAY AND CHARLESB. GRADY,

or NnwfroaK, N. 'Y.; SAID GRADY ASSIGNOR TO SAID MURRAY.

APPARATUS FOR TRAPPING PARTICLES IN SUSPENSION IN GAS-CURRENTS.

Application filed January 9, 1913.

T 0 all whom it may concern Be it known that vwe, THOMAS E. MUR- RAY and CHARLES B. GRADY, citizens of the United States, residing at New York, in the county of New York and State of New York, have invented a certain new and useful Improvement in Apparatus for Trapping Particles in Suspension in Gas-Currents, of which the following is a specification.

The problem which we have solved is to entrap the maximum percentage of solid particles entrained with and suspended in a gas current. This problem presents itself in the arts under manyanddiflerent conditions. Those underwhich we' have encountered it and which are therefore dealt with herein as typical, arise from the need \vhich exists especially in cities and densely populated areas, of preventing the discharge of cinders and other solid'matter' in comminuted form from chimneys connected to boiler fluesespecially when forced draft is used and when changes in 'th'e load de' mand the driving of the boilers :to varying limits often much beyond their ratings.

This is especially the case when the boilersfurnish the power for electric lightingin stallations, thedema'nds' upon them then varying at different periods of the day,1and' sometimes suddenly increasing. The gas currents in the fiues then vary greatly in velocity, with corresponding variations'in the quantity of solid matter entrained.

WVe provide a body of liquid, preferably water, which receives and retains the particles projected upon it." We project the stream of particles vertically downward upon the surface of said liquid.

When the gas current varies in velocity, we vary the cross sectional area of the delivery'outlet proportionately to'said veloc-' ity, so that as this velocity decreases, the area will decrease, and as the'velocity increases, the area will increase, thus maintaining a constant-or substantially constantvelocity'of the projected jet of particles, and thus neutralizing the effect of the velocity changes in the current in the flue. If, therefore, at the outset, and for some selected velocity of flue current, the interval between the delivery outlet and the liquid level be chosen which will be, on the one hand, sufliciently large not to impose a constriction in the path of the escaping Specification of LetterslPatent.

Patented June 17, 1913. Serial No. 740,947. I

gases, and, on the other, not too great materially to diminish the. inertia of the projected particles before they'st-rike the liquid, then it is obvious that no matter what conditions arise in the boilers capable of changing that velocity, by vkeeping the velocity of the projected jet constant, we can maintain the advantageous status previously decided upon, or, in other words, eliminate the effects of the varying conditions.

In addition to varying the escape outlet to maintain constant velocity, we may also vary the interval'betw'een the level of the liquid and said outletor point of projection of the particles proportionately to the change'inaareaof said outlet.' For, obviously, if the area diminish to keep the discharge velocity constant, then the quantity of discharge per giventime will be reduced.

.Because of this, we can reduce the interval between; outlet and liquid level to an extent sufficient to accommodate this diminished quantity of outflow. 'Then because the liquid level has been brought nearer the discharge-outlet,thejetof projected particles will strike the liquid with greater energy than .-before,: will, therefore, more deeply penetrateit,'and sol'will become more efliciently'trapped. v"; i

Wehave inventeda method and an apparatus .which is the best we now know for carrying said method into practical effect.

"Our present invention is the apparatus, more particularly: set forth in the claims. In anotherapplication for Letters Patent, Serial yNo. 740,946 1 simultaneously filed herewith,-we have set forth 'said method.

1 In the accompanying drawingsFigure 1 is a section of our apparatus on the line as, a; of'Fig. 21 "Fig". 2 is a section on the line y of Fig. '1. Fig. 3 shows the relations of the discharge orifice and the water level as in Fig. '1, but on a larger scale.

Similar letters-of reference indicate like parts.--

A is a flue, leading from'any source of gas current, which entrains in suspension the solid particles which are to be trapped. Such particles, for example, may be cinders, flue dust, ash, unconsumed carbon, or any other comminuted material present in the gas current in the flue of a steam boiler. The flue A communicates with an enlarged flue B, through the top wall C thereof. One end of flue B is closed by wall D. The

other end, shown broken ofl", in practice communicates with. a chimney. or other escape conduit. At the bottom of the. flue B is a tank E for holding water. Said tank is preferably, made of cement, or other material, which will resist the attack of such acids as may be formed by, the gas combining with said water. Within the flue B and terminatingatits lower edge, below the horizontal plane coinciding with thewater-level in the tank E, is a narrow verticalpartition'F. 7

' G is a'swingting plate extending between the partition F-and endwall D. Said plate is hinged to the upper wall of flueB in any suitable way. Ashere shown, it has a hooked upper edge-:11 which-is received upon the water supply pipe I, which pipe is supported on the underside of the .topxwall C. The swinging plate. G, the longitudinal wall J of flue B, the end wall D, and the fixed partition F, formv a substantially funnel-shaped continuation of the-:flue A, which terminates above the liquid level in tank E, so that the solid.-particles-escaping at the outlet a, Fig; 3, ofi said continuation: are projected upon the 2 liquid in a direction normaltothe liquidasurfacefi flit will be obvious that b'y -swinging.- the plate Gnearerto thewalt J ,-the area of said. outlet axwill diminished, and -bylswinging therplate Gr farther from- ?the -wa'll J; the area 1015 irs aid outlet amwill 'beZincreaSed. In order to swingwthepplate G for the -purpose: of ad justingasaid :outlet? area? we)? here show a drurncK mounted in I brackets FD on ithe exte riorofwall- J, and connectedetoplate G. by a chain; s-passing through said: wvall; Said drum is turned by the cranlc handleiltfi and:

0% isprovided withf' -a. pawlizandi ratchetN,

whereby .'the position. .i

The water supplyntoitank .ispreferably admitted) in a? constantxandwregulated flow from uthe'e-pipefO," communicating with any suitable 'source whioh pipe connectsTbyI pipe.

I" with .thepipe-LY f-iThG pipe I is perforated and'aisglocatedi at -th'e topof plate-G, so that asheet;ofcwater Q,- fiows downithe inner side stream; may Ibex-regulated .by thel'valve R inzp p P. ul. 1 i; i

Water fiovs-irormtheitanlc E3 by the pipe Si located near the bottom; thereof and provided outside the tank with a hinged section taneously. Hence, for example, when the area of the outlet a is reduced, the water level in tank E is correspondingly raised from the line b to the line 0, Fig. 3.

The operation is as follows: The gas cur rent holding the solid particles in suspension enters the top of flue B between the swinging plate G and wall J, and passes downwardly, meeting the descending water stream Q. The current then escaping through the outlet 0,, the solid particles are projected downward upon the surface (indicated by line 0, Fig. 3) of the water in tank E. The gas passes through the interval d between the lower end of the swinging plate G and the liquid surface 0, and then travels through the flue B to the chimney or other outlet. The downward projection. of the particles is assisted by the wvater stream Q, delivered into them. The particles after striking the water in tank E, enter the same and so become trapped.

Attention-isnow called to the fact that the passage of which plate G forms a swinging wall has art inlet e,: Fig. 1, of substani tially the area of. the flue A; while, when the plate Gz'i's-in the'posit'ion shown in dotted ;lines, 'Eigss-l and'3, the area of the then gexisting escape outlet d'is less than that of inlet e. l'Asithecrosssectional area of the lpassageifrominlet'e to the escape outlet a idecreasesgithe velocity ofrthe gas current is increased- Hence the; inertia of the projected solid" particles is increased. As this increase variesas'the square of the velocity, andra's the-resistanceof the projected particlsto. an force tendingito ohange' their idir ectio niof travelv varies as the inertia, the result is-a very. efieetive trapping of the particles byithewater."

:.IEestsi" adezby usupon an actual apparatusicohstructed; substantially in accordance without-present disclosure show thatit is possible to make the-velocity of the gases at? the escapeouth'ata or point of projection ofi-the articles from two to eight times greater: ban the ordinary velocity of travel ofgasesin boilerfiues, and still not seriously afl'ect tliedraft.

It will belobserved that the cross sectional area of. the funnelshaped passage bounded by: plate G is gradually reduced so that the velocityofi the particles before projection will be gradually increased. In actual practice,- we-findthatthelength of saidpassage may be from two to ten feet, but it is betterto make-it as long as possible so that the particles maybe carried gradually to a velocity at the outlet a, "relatively much higher than that which they have in Hue A.

In many steam power plants, the quan tity of steam required from the boilers varies considerably and quite rapidly throughout the day. For instance, a boiler may be running at a certain rating and the esa-ps4 demand: may be such; that double this-rating: may. be required: in a comparatively shont-spaceof't-ima \Vheni theboiler is runn-ing at double rating, approximately twice as much gas will be delivered from flue A. In using ourapparatus in suchcircumstances, the swinging plate G iSi normal ly set in a selected position which gives an outlet area a to produce a certain: escape velocity ot the particles suitable to\ a certain rating-sa v the position shown in flull lines in Fig. 1. It the: rating is augmented-say doubledthenthe pawl and ratchet mech' anism'N is. released and the/plate is pen-1 mitted to swing to another position whereby the escape area a: is increased to-a-'. sufliciently to reduce the velocity to that previously chosen-say the position shown in dotted lines in Figs- 1- and 3 or, in. other. words, by suitably adjusting: the escape-area at a, the rating of the boiler'isexeeeded, we may keep the velocity of the particles constant at their point of projection. orcscape orifice.

Incaseswhere the velocity of the current in the flue varies, especially when forced draft is used, it is desirable notonly-to vary the area of the outlet a so as: to maintain the velocity there constant), but also'to vary the interval (2 or length of the projected iet.

of particles between said: outlet-and, the liq; Said interval should not be; less.

uid level. in area than the area of outlet a. On the other hand, it is desirable to make it as small as possible. Let it now be assumed, for purposes of present explanation, that the plate G and the pipe section '1 are in the positions shown in dotted lines. The corresponding water level is then at b. l/Vhen the velocity of the flue current falls off, the handle M is operated to bring the plate G into the position shown in full lines, thus reducing the area of outlet from a to u, and increasing the velocity to normal rate. The velocity being keptconstant, it follows that the amount of particles projected will be less as the area of discharge is constricted. Hence the interval at d from partition G to level I) may be diminished by raising the water to level a. This is effected as already explained, with an increase in the trapping efliciency.

Tests made by us with this apparatus applied to four (350 H. P. boilers have shown that. ninety-two per cent. of the cinders or flue dust delivered to the apparatus was trapped in the water, and prevented from passing to the chimney.

In order to remove the accumulated cinders or like material from the tank E, we provide a branch pipe U from the water supply pipe 0 which has several inlets V into said tank. Similar outlets are provided on the opposite side of the tank which communicate with a settling vessel 7. When it is desired to clean out; the tank, the gas cuurentfromthe flue-A is shut cit, the valve H. in pipe P is: closed to cut ed the water supply, and the va-lveX inpipe U is opened. The water entering the several inlets V sweeps the sol-id material to theoutlets, and: said material is collected and drained in the settling vessel We claim:-

1. A. device for trappingparticles in suspension in a gas current, comprising-a duct receiving saidcurrent and tapering down- \vardl-y to an outlet, means for varying the (moss sectional area-of saidoutlet, and: a tank containing liquid disposed below said outlet and receiving the particles projected theuefrom.

2; A device for trapping particles in suspension in a gas current, comprising-a tank, and: a duct deliveringsaid particles: vertically downward upon the-- liquid in said tank; a portion of the wall of said duct: being movable to vary the cross sectional area of the outlet-ofsaid duct. Y

3. A device for trapping particles in: suspension: in a gas current,*comprising a) tank, and a duct delivering said particles verti Cally downward upon the liquid in said tank; a portion of the wall of said duct-be: ing suspended to swing and movable to vary the, cross sectional. area: of. the; outle rpfssaid iduct;

- 4. A device for trapping particles in suspension in a gas current, comprising a horizontal flue, closed at one end, a partition extending partly across said flue, a swinging plate suspended from the top of said flue at a distance from a longitudinal wall thereof and interposed between said partition and the closed end of said flue, a tank disposed in said flue below the space between said plate and said longitudinal wall, means for delivering the gas current into said space at the upper part thereof, and means for moving said plate to vary the distance of the lower edge thereof from said longitudinal Wall.

5. A device for trapping particles in suspension in a gas current, comprising a tank, a duct delivering said particles downward upon the liquid in said tank and having one wall inclined toward the outlet, and means for delivering a liquid stream upon the surface of said inclined side.

6. A device for trapping particles in sus pension in a gas current, comprising a tank, a duct delivering said particles downward upon the liquid in said tank, means for varying the cross sectional area of the outlet of said duct, and means for varying the distance between said outlet and the liquid level in said tank.

7. A device for trapping particles in suspension in a gas current, comprising a tank,

a duct delivering said particles downward upon the liquid in said tank, means for varying the cross sectional area of the out let of said duct, means for varying the distance between said outlet and the liquid level in said tank, and mechanism for simultaneously controlling both of said means. 1

8. A device for trapping particles in suspension in a gas current, comprising a horizontal flue, closed at one end, a partition extending partly across said flue, a liquid supply pipe, having perforations, at-the top of said flue, a swinging plate suspended from said pipe and receiving the liquid stream therefrom, the said plate ;being placed at a distance from a longitudinal wall of said flue and interposed between said partition and the closed end of said flue, a tank disposed in said flue below the space included between said plate and said longitudinal wall, and means for delivering, a gas current into the upper part of said space. v I

9. A device for trapping particles in suspension in a gas current, comprising a duct receiving said current and tapering to an outlet, and means for delivering a stream of liquid upon the inner inclined surface of said duct.

1( A device for trapping particles in suspension in a gascurrent, comprising a vertical duct receiving said current at its upper end and having one wall suspended and movable to vary the area of the outlet, and means for delivering a stream of liquid witllliin said duct and upon said'suspended W3. f 1 v 11. A device fontrapping particles in suspension in a gas current, comprising a duct conveying said current, an inclined plate transversely placed therein, and means for delivering a liquid stream upon the side of said plate receiving the impact of said particles.

12. Av device for trapping particles in suspension in a gas'current, comprising a vertical duct conveyin said current, an inclined plate suspended t erein, and means for delivering a liquid stream upon the upper side of said platen-1:

In testimony whereof .we have aflixed our signatures invpresence of two witnesses.

THOMAS E. MURRAY.

Copies of this patent may be obtained for five cents each, by 'aiid'r'ess'iligthef Commissioner of Patents,

Washington D. C.

1 QGHAii EsE RADY, 7 a

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