US1747820A - Spark arrester - Google Patents

Description

Feb. 18, 1930. E. FALKENTHAL.

SPARK ARRESTER lFiled May 11, 1925 :s sheets-sheet Feb. 18, 1930. E. FALKENTHAL 1,747,820 SPARK ARRESTER Filed lay 1l, 1925 3 Sheets-Sheet 2A Feb. 18, 1930. E. FALKENTHAL SPARK ARRESTER Filed May 11. I 1925 3 Sheets-Sheet l -1/ 1 l l 01455 Patented Feb. 18, 1930 UN ITE'D STA TES 'PA TE N T FF I C E 'SPARK ARRESTER Application filed May 11, 1925, Serial No. 29,548, and in `Germany .Tune 3, 1924.

This invention relates to devices for arresting sparks which escape from the heating flues of locomotives, and other moving or stationary engines particularly such as have fire tube boiler installations.

The object of my invention is to provide a spark arrester by the use of which the most minute incandescent particles, which are car riedalong by the hot gases, shall be positively `1.0 arrested by a sieve, but in such a manner that the putting in operation of the sieve rproduces no throttling of the air draught necessary for the heating iues. For the purpose referred to, a smoke chamber is constructed in front of l5 theflues With two compartments traversed vin succession by the hot gases, so that one of these compartments being connected With the chimney and the other With the flues, the tWo compartments being completely separated from f' 20 each other by the sieve in question. This sieve is made of very thin sheet metal and is provided With lvery fine and very closely-distributed apertures, the total perforated areaof Which `forms %-40% of the entire area of -25 the sieve, Whichis lat least four times that of the total cross-sectional area of the Vfire tubes.

Various devices have already been proposed wherein a sieve is interposed'in the path of the f hot gases. In these devices the sieve consists 40 choked.

vIn all the forms of constructionl known hithertothe supercial area of the sieves has not beengreat enough, so that their through passagearea 4was insufficient in comparison' With the-total:cross-sectional area of the fire tubes. The result of this Was a throttling of the draught, sothat, apart altogether from the defect of choking, such sieves could not fulfil the requirementsvand so never came into general use. f

As anauxiliary device it has been proposed to provide, along With the sieve, another open passage for the hot gases on their Way from the flues to the chimney, but it is obvious that l such a passage would tend to nullify the purpose of the entire installation, as there is nothing to prevent the hot gases, which rush With great energy right through this open passage, from drawing quite large incan-descent particles with them to the chimney.

To secure an effective arrest of any incandescent particles of Which the smallest liable to start a fire may, according to results obtained With lignite and Wood firing have a diameter of 2 to 3 mm., it is necessary that all the hot gases be conducted through the sieve and through the sieve only, an-d that the apertures in the latter should be of appropriately small Width. The throttling of the draught, which would otherwise inevitably occur, is, according to the invention, avoi-ded by arranging that the entire upper surface of the sieve be made equal to at least four times the total cross-sectional area of the ire tubes and that the passage area of the sieve be equal to at least 25% of its entire surface. by constructing the sieve of very thin sheetmetal of approximately only 0.8 to 1.5 mm. in thickness, a channel-like formation of the apertures and their consequent choking by soot and ash are, as experimentsV have demonstrated, completely avoided.

A peculiar circumstance which yassists in producing this effect is the fact that eddiesA are formed not only in front of.`v but also be hind, the sieve, and that these eci-dies, in cone sequence of the regular formation of soot and ash particles which penetrate through the apertures of the sieve and Would otherwise readilyrsettle on the rear edges of said apertures.

yeffectively prevent any gradual choking of the openings. In order to prevent rapid combustion of the sheet metal, the latter is preferably constructed from some non-rusting material. Experiments have shovvn that the most suitable material for this purpose is chrome-nickel steel, which also is not attacked by any of the aci-ds in the hot gases, so that it possesses a practically unlimited life. It has moreover, a materially'higher strength than ordinary sheet metal so that, in spite of the very small thickness referred to, it can be subjected to rough usage without injury. This is important, in view of the fact that the smoke box must frequently be opened for the purpose of cleaning the lire tubes and of removing the soot and ash, and that parts of the sieve must be removed at the same time and are therefore very liable to injury.

It is another object of the invention to provide a sieve of the kind just described, (having a large superficial area) which can be fitted within the narrowest and most conlined smokeV box, (through which also the live steam pipe and the steam exhaust or blast pipe are frequently led,) in such a manner that it may be removed with the aid of a few handles when the cleaning referred to has to be carried out and reinserted with equal ease.

In cases where the smoke box is unusually small or its available space is diminished by thevaccommodation of a super-heater or the like, the sieve is not arranged in the smoke box proper, but the latter is partitioned off into two chambers by a solid sheet metal wall, one of the compartments being, as before, connected to the chimney and the other to the tube-plate, the sieve, however, being located inside a casing situated outside these two compartments, and the two compartments into which this casing is divided by the sieve, communicating with the other two, so that the hot gases traverse the entire series of chambers in succession, passing through the sieve on their way.

Generally speaking, it is advantageous to avoid a direct collision of the hot gases, as they issue from the smoke box, with the sieve. To effect this, deflecting surfaces of solid sheet metal are arranged in such a manner as to conduct the hot gases to the upper surface of the sieve tangentially.V By reason of the centrifugal action exercised on the particles as they are carried along in such a path, the larger of the incandescent particles are hurled against the deiiecting surface and there fall down, without ever reaching the sieve. The duty of the latter is only to arrest the smaller of the incandescent particles which, however, reach it in great numbers, more particularly when the engine is working under light load.

' In the drawings z# Fig. 1 is a longitudinal section and Fig. 2 a part sectional end elevation of a locomotive smoke box with a blast pipe forked directly below the chimney outlet, and detachable sieve-pipes situated in front of the blast pipe.

Fig. 3 is a part sectional end view and Fig. 4 a longitudinal section (both diagrammatic) of a locomotive smoke box with a blast pipe forked directly below the chimney outlet,

and a detachable sieve-pipe lying below the blast pipe.

Fig. 1 shows the smoke box b of a locomotive, in which a main steam pipe p and a forked blast pipe g are situated, directly in front of the flue sheet a. In this figure, the fire tubes or flue sheet a are omitted from the drawing but must be assumed to be present. In order to mount a sieve according to the invention, the mouth of the chimney d has been tightly closed by amultiple-stepped box 7, which has two circular apertures s on its front under surface. To these two apertures are applied cylindrical sieve-pipes g land z, both closed at the bottom end and by means of a handle t after releasing the bolt u, each .sieve pipe can be drawn out in the direction of the arrow (Fig. 1), sliding, for this purpose, in the grooves o of the box 7' (see Fig. 2). l

The blast nozzle g1 of the forked exhaust pipe g passes through and makes a tight joint with the under floor of the box 7'. The hot gases passing through the lire tubes of the flue Asheet a proceed thence'in parallel streams through the large-surfaced sievepipes g, 71, into the inner chamber of the box r, and thence to the chimney CZ.

In Figs. 3 and l a smoke box similar to that shown in Figs. 1 and 2 is illustrated. The blast nozzle g1, of the forked exhaust pipe g is carried through the bottom of a box 1', which, as in Figs. 1 and 2, tightly closes the chimney mouth (Z1. The box 7' in this case, is furnished with two ducts r1, extending downward fore and aft of the forked pipe g and embracing the same. These ducts terminate in a plate r2 furnished with corresponding apertures. Grooves o are provided on this plate, into which the sievepipe g is pushed, as in Figs. 1 and 2. The sieve-pipe g is closed at the bottom end by a plate g1, constructed of solid sheet metal or else provided with sieve apertures like the sievepipe itself. The path of the hot gases is shown by the arrows. This construction is useful Where the smoke box has very little depth from front to rear.

Although the present invention has herein been described mainly in its application to locomotives and although it is particularly well adapted for boilers of the locomotive or portable type, I desire it to be understood that I do not limit myself to such particular applications of my improved spark-arrest ing device. Thus the apparatus of my invention is advantageously applicable to various kinds of stationary boilers, heating Vplant and the like and in such cases an improved smoke box, in accordance with the objects of my invention is arranged behind the boiler and its flues or fire tubes, with its sieve interposed in the path of the hot gases on their way to the chimney stack.

CTi

What I claim is l. In a fire tube boiler, a flue sheet, a smoke box, a blast pipe therein, a chimney outlet therefor, a sieve constituting a complete spark arresting barrier between the liues and chimney outlet, an auxiliary box iixed below the chimney outlet and supporting said sieve arrangement, the latter having its lower end closed and spaced from the walls of the smoke box, said sieve being detachably secured tok said box, and a blast pipe discharging. into said auxiliary box.

2. In a fire tube boiler, a flue sheet, a smoke box, a bifurcated blast pipe therein, a chimney outlet therefor, `a cylindrical for easily removing said sieve device from the said box.

In testimony whereof I have signed my name to this specification.

ERWIN FALKENTHAL.

sieve constituting a complete spark arresting barrier between the ues and chimney outlet, an auxiliary box iixed below the chimney outlety and having a transverse channel, the blast pipe discharging int-o said box with the bifurcation in the channel, said sieve being detachably 'secured to said box below kthe channel.

3. In a lire tube boiler, the combination with a smoke box, a .blast pipe therein, a flue sheet forming the rear Vwall of said box,

a chimney outlet therefor and a blast pipe,

of an auxiliary box in said smoke box below the chimney out-let and to which the discharge end of the blast pipe is secured for discharge thereinto upwardly to the chimney outlet, and a sieve removably connected to and` discharging gases into said auxiliary box, said sieve being out of the path of. saidr pipe and the exhaust steam therefrom and having its lower end closed and spaced from the Walls of the smoke box to permit ready and free removal of said sieve device for emptying.

, from the latter.V

5. In a fire tube boiler, the combination with a smoke box, a blast pipe therein, a flue sheet forming a wall of said box, a chimney outlet therefor and a blast pipe; of an imperforate auxiliary box secured at and immediately below the outlet in which the blast `pipe terminates, a depending sieveV device connected to the bottom of said auxiliary box vand havingits lower endclosed and spaced from the walls of the smoke box, a sliding connection between the bottom of the auxiliary box and the open top of said device consisting of slide flanges and clamping levers ira

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