US2647588A

US2647588A - Boiler tube fly ash collector

Info

Publication number: US2647588A
Application number: US138806A
Authority: US
Inventors: Carl E Miller
Original assignee: Bituminous Coal Research Inc
Current assignee: Bituminous Coal Research Inc
Priority date: 1950-01-16
Filing date: 1950-01-16
Publication date: 1953-08-04
Anticipated expiration: 1970-08-04

Description

Aug. 4, 1953 c. E. MILLER 2,647,588

BOILER TUBE FLY ASH COLLECTOR Filed Jan. 16, 1950 3 SheetS-Sheet l F/GURE INVENTOR. Carl E. Miller B Mm .45

AGENTS.

Aug. 4, 1953 c. E; MILLER BOILER TUBE FLY ASH COLLECTOR 3 Sheets-Sheet 2 Filed Jan, 16, 1950 F/GURE 2 FIGURE 3 INVENTOR.

w m wan 1r. I A w Aug. 4, 1953 c. E. MILLER BOILER TUBE FLY ASH COLLECTOR 5 Sheets-Sheet 3 Filed Jan. 16 1950 F lGURE 4 F IGURE 5 INVENTOR. Carl E. Miller ,m, WM

A 7' TOHNEYS Patented Aug. 4, 1953 UNITED STATES PATENT OFFICE BOILER TUBE FLY ASH COLLECTOR Carl E. Miller, Columbus, Ohio, assignor, by mesne assignments, to Bituminous Coal Research, Inc., Pittsburgh, Pa., a corporation of Delaware Application January 16, 1950, Serial No. 138,806

3 Claims.

This invention relates to fly ash concentration, and more particularly to a combination fly ash concentrator and a fire tube boiler.

The problem of atmospheric pollution by fly ash and cinders has been solved to a great extent in the past by the use of various types of mechanical collectors and concentrators. However, in the prior art, every device which has been suggested or used has materially increased the size of the boiler, and the cost of installation. Cost of installation and size are primary considerations in the installation of any type of boiler. Moreover, the size of the boiler becomes a much more important factor in determining its desirability when the boiler is installed in a vehicle, such as a locomotive or a ship, where space often is at a premium. Consequently, a fly ash concentrating or collecting device which utilizes a considerably smaller amount of space than collectors or concentrators in the prior art, is an extremely desirable addition to the art of smoke abatement.

It is therefore one object of this invention to provide a combination fly ash concentrator and fire tube boiler.

It is another object of this invention to provide a combination fly ash concentrator and fire tube boiler which occupies a minimum amount of space, and which can be fabricated at a minimum cost, for a particular boiler rating.

It is a further object of this invention to provide such a device wherein the overall efliciency of the boiler is materially increased.

It is a still further object of this invention to provide such a device wherein the quantity of fuel consumed is materially reduced.

Various other objects and advantages of this invention will become apparent to those skilled in the art upon reading the followingspecification in conjunction with'the accompanying drawings in which:

' Fig. 1 is an elevation view, partly in section, illustrating this invention;

Fig. 2 is a fragmentary perspective view, partly in section, with portions broken away, showing a particular portion of this invention;

Fig. 3 is a fragmentary perspective view, partly in section, with portions broken away, showing a modification of a particular portion of this invention;

' Fig. 4 is a fragmentary perspective view, partly in section, with'portions broken away, of a 'further modification of a particular portion of this invention; and

Fig. 5 is a further fragmentary perspective viewof the device shown in Fig. 4..

Referring now to the drawings, and more particularly to Fig. 1, a fire tube type boiler is indicated generally at I. This particular embodiment is a horizontal return tubular boiler, but it is to be understood that the invention is equally adaptable to any other type of fire tube boiler. In the embodiment shown in Fig. 1, the boiler is provided with a stoker 2, a feed hopper 3, and a motor 4. While there has been shown a stoker fired, coal burning boiler, oil fired boilers and other forms of stoker fired boilers are to be considered as coming within the scope of this invention. The fire bed is in the general area indicated at 5 and the hot gases, formed by the combustion of the fuel, flow upwardly and then through the tubes in the directions indicated by the arrows. A primary fly ash concentrator 6 is located in each fire tube 1 near the discharge end thereof. Breaching 8 conducts the cleansed gases from the fire tubes to the stack 9. In this particular embodiment of the invention a cyclone air separator I0, with an air tight receptacle ll attached thereto, is connected to the discharge side of the fire tubes 1 by means of duct l2. The cleansed gases leave the cyclone air separator at l3 and flow in the direction indicated by the arrows through duct I4, fan l5, and duct [6 into the stack 9.

A concentric pipe l! is fitted within each of the fire tubes 1 near the discharge end [8 thereof. This concentric pipe is also shown in Figs. 2, 3, 4 and 5. Pipes I! are securely fastened in the tube sheet I9, and the upper fire tubes 1 are securely fastened in the tube sheet 23, which is positioned parallel to tube sheet l9. Tube sheets I9 and 23 are spaced, and the space between them opens into duct [2.

Referring now more particularly to Fig. 2, 24 is a cylindrical member, preferably having a hemispherical end 25 (see Fig. 1) and a flat end 26, which lies in a plane perpendicular to the axis of the fire tube 1. The gas flow is in the direction indicated by the arrows. Cylindrical member 24 is equally spaced from the inner wall 21 of the fire tube l, and within which it is secured, by helical vanes 28. It will be apparent from Figs. 2, 3, 4 and. 5, that pipe I1 is only slightly spaced from fire tube 1 at the discharge end l8 thereof, thereby providing a small annular space 29.

A modification of the device shown in Fig. 2 is shown in Fig. 3. In this modification, there is provided a similar cylindrical member 24, coaxial with and secured within the fire tube 1,- However, this particular concentrator difiers from and having its periphery equi-spaced from the surface El of the fire tube 1, but lying-in'a plane parallel to the plane in which the ring 8i lies, is a disc 32. Disposed"between the ring and the disc and firmly attached"thei'et'dare a plurality of vanes 33, which areplanar, long'i tudinally extending, and would be-tangent to" a cylinder coaxial with said fire tube, but of a smaller diameter than disc 32.

While this invention has been shown in its preferred embo-zlirn'ents it is to be under-stood that it is not to be consideredflimited' to' the mere embodiments disclosed herein. For instance,- the boiler may be 'of a type other than horizontal return tubular. The stoker could be of any type; the cyclone a'ir separator i ii could be replaced by an electrostaticairseparator, and the fuel could be'o'ther than coal, such as oil or gas. It is essential that there be a pre'ssure drop between-the discharge ends user the firetubes "i and the secondary concentratoror separator as. However, such a pressure dropni'ight be accomplished by inean's other than a fani5. For instance, in the-case-o'fa loc'emot'ive installation, it might be very desirable-tense a steam jet, utilizing waste steam, thereby providing the necessary pressure drop lvforeoveifi thecleansed gasesdo not neceshave to go-to the stack, as has been shown butif their heat values-are high they n11- "it very well 'go-to an air preheater. I

erniore,'='this invention'is not tobe con limited to the particular embodiments of the-primaryfly ash" concentrating device" as diselosed'in Figs-*1, 2, 3, 4 and'f). The broad concept cf -this invention includes any type of concentrating 1 and separating device which is loat i withina fire tube and functions to 'con centr' te i'iy ash and separate gas fIOlIl' fiyashby' the ash toward the outer periphery of tube'a.rid* 'thencef removing the fly ash from re s tuba-while thegreaterfpo'rtion of thegase move toward'the'center of the tube. ln' oper ing this devica'the hot fly ashladen" gases p threngh the fire tubesin the direc tions" indicated by the arrows, and when they" reaehthe concentrator 6 are given a whirling motion. Since the particles of fiyasli'or'o'ther solids are heavier than these hot gases; these parti lesare thrown" toward the inner surfaes" of the'tub'e l but continue to travel in a'lon'g'itudina'l' directionln eifect, the path of the gase's'"and" the fly ash i's somewhat of a helix after their direction has be'e n cha nged bythe primary con-" centra'ctore. -When the gases' a'nd'the' flyash reaclrthe section i 8 of the tube i, the essen es passthro'ugh the'pipe ll', and

tially thehce out to tl stack; The fly ash; which has a small amen of gas associated therewith, is sklii fined oif .nougn the annular space'29"and drawn down into the duct 52, due to the drop in me sy ash H thei witlie The 1 gases which are associate-(r y asli drops down "into the" 4 sealed receptacle Ii, while the gases then travel through ducts l4 and it to the stack 9.

In the Various embodiments of the primary concentrator which are shown in Figs. 2, 3, 4 and 5, preliminary concentration is effected in essentially the same manner. In each case, the concentration of fly ash in the exhaust gases is greatly increased in those exhaust gases near the inner surface of the tube l and practically eliminated in the interior, axial zone of the tube 1. Therefore, the interior portion of tube 1 contains practically pure exhaust gas. This is accomplished, in each case by giving the combined gas and'flyash a twisting motion, the heavier fly ash and cinder particles moving toward the inner surface of the tube l, and the lighter exhaust gases moving toward the center axis of the tube.

A true synergistic effect is achieved by means of the novel combination constituting this invention. A substantial amount of heat-is transferred in the portions of the tubes 5 between the end portions i8 thereof and the portions adjacent the ends 25 of the primary concentrators. -When the fiy ash particles are whirled toward the inner surface of the fire tubes, in a helical'path; not only is there effected a separation of gases and ash, but an unexpected, important, additional result is achieved. The fly ash particles, because of their helical path, and because they skim along the inner surface of the fire tubes, remove any soot particles which cling to such inner surface and, consequently, a scrubbing and cleaning action is realized. Since mount of heat that transferred through tubes is appreciably lowered when a layer so t formed on the inner surfaces of the fire tubes, the removal of this soot layer by the scrubbing action of the whirling soot particles appreciably improves the heat transfer characteristics of the fire tubes, and substantially reduces thequanity of fuel required. Therefore, the primary concentrators, in additio'nto functioning as concentrators and separators, when combined with fire tubes in thismann'er, function to cleanthe inner surfaces of the fire 'tub'es'.

Moreover, in addition to the fact that the fly ash is eifectively separated from theexhaust' results'in a'savi'n'g in space of as much as appren- Moreoverfrather than" burden the purchaser witha number of separate units,'this particular invention may be purchased as a composite articlewithconsequent savings in-initial purchase cost, maintenance'costs, freight charges, and" sundry other expenses.

Froin'the' foregoing it should be obvious that there has been devised a new 'andnovelcorn"- b nanonwnien results in increased boiler efficienc'yQTeductiOn in size" or the boiler unit, reduction in fuel consumption of the boiler, reduction in the initial cost of the boiler and reductibn in maintenance cost of the boiler;

Whileit his"inventionhas been described in its preferred embodiment; it is to be understood that the words used are wordsof description. rather"than "of"'li'mitat'i'on, "and that changes within the purview"o'f 'theap'p'ended claims may be made without departing from the true scope and spirit of the invention.

What is claimed is:

1. The combination of, a fire-tube boiler provided with a plurality of spaced fire tubes therein, each of which said tubes is adapted to conduct hot gases therethrough, and which said tubes, during operation of said boiler, are surrounded by a fluid which is to be heated, and a fly-ash collecting system comprising fiy-ash and gas separating and concentrating means wholly within each of said tubes, whereby there is provided a relatively clean stream of gas centrally of each of said tubes and a stream of gas high in fly-ash particle concentration adjacent the periphery of each of said tubes, means adjacent the end of each of said tubes for separately conducting said relatively clean stream of gas and said stream of gas high in fly-ash particle concentration, fiy-ash and gas separating means external of said tubes, a conduit connecting said external separating means with said means for separately conducting said stream of gas high in fiy-ash particle concentration, and means for producing a fiow of said stream of gas high in fly-ash particle concentration to said external separating means.

2. The structure set forth in claim 1 wherein said external fly-ash and gas separating means is a cyclone air separator.

3. The structure set forth in claim 1 wherein said fly-ash and gas separating and concentrating means wholly within each of said tubes comprises cylindrical means within each of said tubes and equispaced from the inner surface of each of said tubes by a plurality of radially disposed, longitudinally extending, helical vanes.

CARL E. MILLER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 538,589 Kemble Apr. 30, 1895 630,023 Baker Aug. 1, 1899 1,923,498 Nallinger Aug. 22, 1933 1,970,077 Collins Aug. 14, 1934 2,182,854 Pfeffer et a1. Dec. 12, 1939 2,236,358 Allardice Mar. 25, 1941 2,370,629 Appeldoorn Mar. 6, 1945 2,391,860 Badenhausen Jan. 1, 1946 2,415,935 Bullock Feb. 18, 1947 2,515,894 Polk July 18, 1950 2,569,710 Fitzpatrick Oct. 2, 1951