US2705530A - Soot-consuming device - Google Patents

Description

April 5, 1955 c, MaccRAgKEN 2,705,530

SOOT-CONSUMING DEVICE Filed Feb. 21, 1950 5 Sheets-Sheet 1 IN VEN TOR.

April 5, 1955 c. D. M cRAcKEN ,705,

SOOT-CONSUMING DEVICE Filed Feb. 21, 1950 5 Sheets-Sheet 2 April 5, 1955 c. D. M cRAcKEN sooT-coNsuMING DEVICE 5 Sheets-Sheet 5 Filed Feb. 21, 1950 April 5, 1955 C. D. MaccRAcKEN 2,705,530

SCOT-CONSUMING DEVICE Filed Feb. 21, 1950 5 Sheets-Sheet 4 INVENTOR.

April 5, 1955 C. D. Macc 2,705,530

SOOT-CONSUMING DEVICE Filed Feb. 21, 1950 5 Sheets-Sheet 5 IN V EN TOR.

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United States Patent SOOT-CONSUMING DEVICE Calvin D. MacCracken, Tenafly,

Heet, Inc., Englewood, York N. 1., assignor to Jet- N. L, a corporation of New This invention relates to a soot-consuming device for use with oil burners. The invention is particularly (but not exclusively) adapted and intended for use in a heater of the general type described in my Patent No. 2,488,548, of November 22, 1949 for Forced-Air House Heating Apparatus, which is provided with a heat-exchanger of the general type described in said patent and in my Patent No. 2,488,549 of November 22, 1949, and is also provided with an oil-burner structure of the general kind described in my patent application Ser. No. 277,185, filed March 18, 1952.

The invention has two principal objects, first, to provide a combustion chamber in which substantially all of any soot existing in the gaseous products of combustion coming from the oil-burner will be consumed, so that the gaseous products leaving the combustion chamber will be substantially soot-free; and second, to provide a combustion chamber of small size and low heat-storing capacity through which the products of confibustion will travel with turbulence in a tortuous pat The necessity for eliminating substantially all of any soot existing in the air and gaseous products of combustion as they come from the oil-burner is due to the fact that when those hot gaseous products are utilized in a heat exchanger the deposit of soot therein is objectionable. The necessity for providing a combustion chamber of small size which will store a minimum of heat arises from the nature of the heating apparatus of the type above mentioned in which the combustion chamber is particularly intended to be used. In heating apparatus of the general kind described in my aforesaid patent, the storage of a large amount of heat with in the apparatus is objectionable, because the dissipation of heat from the apparatus normally depends upon the flow through it of air supplied by the fan or air compressor (instead of the natural draft of a chimney), and when that element of the heating apparatus stops functioning for any reason (as in the case of failure of the power driving the fan or compressor) such flow of air ceases.

It is of course common practice to line the fire-box or combustion chamber of oil-burning heating apparatus (such as house heaters) with refractory material of various kinds built up from bricks or blocks or otherwise formed. The practice of the prior art has been to make the space within such a fire-box or chamber so great relative to the size of the flame that direct impingement of the flame on the refractory material is largely avoided, principally to prevent cracking of the refractory material and to avoid the deposit of carbon on the refractory material which may occur at a point of flame contact. As one leading authority has said Oil flames must be allowed to have their full swing. That is to say, according to the prior teaching of the art, oil flames should be given plenty of space in which to burn. In such prior art fire-boxes or combustion chambers, the refractory material is rather massive and heats up rather slowly and stores a large amount of heat, even in the case of so-called insulating fire-brick, but the dissipation of heat from it ordinarily presents no problem. While it is recognized that carbon or soot will be burned to some extent on the walls of such a fire-box or chamber lined with refractory material, once that material is sufliciently heated, I have found that effective removal of carbon or soot from the gaseous products of combustion is not usual "ice in such a combustion chamber. The soot or carbon content of the gaseous products of combustion emanating from such a fire-box or chamber of prior art heaters is usually greater than is permissible in the successful operation of heating apparatus of the general kind described in my aforesaid patents, although said carbon content may cause no serious difficulties in some heating apparatus of the prior art because of the comparatively large dimensions of the passages traversed by the products of combustion.

The present invention is contrary to the teaching of the prior art in that I provide a combustion chamber, mostly lined with rather thin refractory material, which closely confines the flaming gases coming from the oil burner and causes the mixture of air and gaseous products of combustion to flow in a tortuous and confining path with the creation of turbulence, for substantially as long as combustion is taking place, thereby causing the flaming gases and any soot particles to impinge repeatedly on the refractory material of the walls of the combustion chamber. Since this refractory material is continuously heated because the combustion chamber confines the flaming gases, any soot in the mixture of air and gaseous products of combustion flowing through the combustion chamber is quickly consumed. Even when the heating unit starts from a cold condition, the refractory material, due to its small mass and the confined condition of the flaming gases within the combustion chamber, is heated quickly and any soot momentarily deposited on the refractory material is quickly consumed. Therefore, the hot mixture of air and gases issuing from the combustion chamber is substantially soot-free under all conditions and can be directed through the confined passages of the heat exchanger for long'periods of time without danger of clogging them, or said gases may be utilized in other ways where soot-free hot gases are desired. In a sootconsuming device according to the present invention, the length of the passage through the combustion chamber is about equal to the length of the flaming gases directed into it from the oil burner, so that the flame terminates short of or at about the outlet from the combustion chamber. Since the mass of the refractory material which lines most of the combustion chamber is comparatively small, the heat stored in it is not too great to be dissipated without damage to the various parts of the heating unit (such as the electric motor which drives the fan or compressor and the fuel oil pump driven by said motor) when the heating apparatus ceases to operate because of a failure of the current supply to the motor.

The invention will be understood from the following description, taken in connection with the accompanying drawings in which Fig. 1 is a perspective view of a soot-consuming device embodying the invention; Fig. 2 is a longitudinal sectional elevation on the plane 2-2 of .Fig. 1, and also shows in section a fuel burner in cooperative relation to the soot-consuming device; Fig. 3 is a sectional plan view on the plane 33 of Fig. 2; Fig. 4 is a sectional elevation on the plane 4-4 of Fig. 3; Fig. 5 is a sectional elevation through a wall of the soot-consuming device illustrating how a flame electrode is mounted therein; and Fig. 6 is a sectional elevation, similar to Fig. 2, showing a modified construction of said soot-consuming device.

In Figs. 1, 2 and 3, the soot-consuming device is shown as having a box or dome portion 10 and a cover or bottom portion 12 which are adapted to cooperate with one another (as hereinafter described) so as to provide a combustion chamber 14 which receives the gaseous products of combustion from a fuel burner 16 shown in Fig. 2, which may be of any suitable kind, the one illustrated being shown and described in my co-pending application Ser. No. 277,185.

As will be evident from Figs. 2 and 6, the fuel burner 16 there illustrated is provided with a liquid fuel nozzle or atomizer 18 of the return-flow type having a supply pipe 20 and a return pipe 22. The atomizer 18 supplies the fuel oil in the form of a fine cone-shaped spray, as indicated in Fig. 2. The fuel burner has an inner cylindrical shell 24 and a slightly tapering outer shell 26,

which are retained in concentric relation by a circular dish-shaped end wall 28 having its outer portion formed into a circular channel which cooperates with the top edges of the shells 24 and 26 and is secured thereto in any suitable way. The end wall 28 is provided at its center with an opening through which the fuel spray from the atomizer 18 enters the combustion chamber; and mounted on the end wall 28 is a casing 32 which houses the atomizer 18. The inner shell 24 of the fuel burner is perforated with a large number of small holes 34 and 36, and is also provided with several series of circularly arranged larger holes 38, as will be apparent from Figs. 2 and 6. The purpose of the small holes 34 and 36 is to permit air to seep through the inner shell 24, thereby providing on its inside surface a layer or cushion of air; and the larger holes 38 in the inner shell 24 admit freely not only the air necessary to support substantially complete combustion of the liquid fuel, but also additional air which dilutes the gaseous products of combustion. As shown in Fig. 2, the lower part of the inner shell 24 is surrounded by a baffle 40, the major portion of which is spaced away a short distance from the end portion of the perforated inner shell 24. This battle 40 retards and increases the heating of the air seeping through the small holes 36 into the lower portion of the fuel burner. An ignition device 42 (of any well known form) is shown as extending through aligned openings in the shells 24 and 26 into the combustion space Within the inner shell 24. It will be understood that the fuel burner 16 and soot consuming device are located within a casing (not shown) to which air is supplied under pressure; and that this air enters the annular space between the outer shell 26 and the inner shell 24, as indicated by the arrows a. The major portion of the air enters the combustion chamber through the larger openings 38 in the inner shell 24, but some of said air seeps through the openings 34 and 36 in the inner shell 24. The air passing through the annular space between the shells 24 and 26 absorbs heat from the shell 24 before passing into the combustion chamber and also serves to moderate the temperature of the outer shell 26. The fuel burner, therefore, supplies to the sootconsuming device a flame containing the gaseous products of combustion and an excess of air which facilitates the consuming of any soot, in the manner hereinafter described.

The soot-consuming device will now be described. Referring to Figs. 1, 2 and 3, the box or dome portion 10 of the soot-consuming device is shown as having an outer shell comprising a bent Steel plate 44 forming the top and ends, and steel plates 46 and 48 forming the sides, which are welded together and lined with refractory material 50. Said refractory material 50 is preferably reinforced during the molding of it with a looselywoven wire fabric 52 which serves to preserve the form and usefulness of the refractory material even if it becomes cracked under the influence of the heat applied to it. As will be apparent from Figs. 2 and 3, the refractory material 50 lines the top and side walls of said box or dome portion 10.

Extending from the top portion 44 of the shell and cooperating with the sides 46 and 48, is an inclined plate 54 having therein an entrance opening surrounded by a flange 56 which (as shown in Fig. 2) is adapted to receive the end of the inner shell 24 of the fuel burner. Also extending from the top portion 44 of the shell and parallel with the inclined plate 54, is a sheet metal apron 58 provided with an opening concentrically arranged with reference to the flanged opening in the inclined plate 54. The outer shell 26 of the fuel burner cooperates with the apron 58 in the manner shown in Fig. 2.

The cover or bottom portion 12 of the soot-consuming device is welded as indicated at 59 in Fig. 4 or otherwise secured to flanges 60 extending from the edges of the sides and end of the shell of the box portion 10; and said cover or bottom portion 12 is provided near one end with an exit opening surrounded by a flange 62, as shown in Fig. 2. As best shown in Fig. 2, the cover or bottom portion 12 is provided with a deflector or batfle 64 of refractory material which is preferably reinforced with a loosely woven metal fabric 66 which serves the same purpose as the fabric 52 embedded in the refractory lining 50. As shown in Fig. 2, the bottom plate 12 has welded to it a sheet-metal angularly-extending member 68 which projects into the baflle or deflector 64 and prevents gases from flowing under the baflle.

In the form of the invention illustrated in Figs. 2, 3 and 4 the'cover or bottom portion 12 is provided, at the end adjacent the entrance opening in the inclined plate 54, with a specially constructed flame-deflecting plate portion 69 against which the flame from the fuel burner 16 impinges. The construction of this plate portion 69 will be understood from Fig. 4 which shows that it consists of a plurality of channel members 70 made of some metal alloy which is oxidation-resistant at high temperatures, such as an alloy containing about nickel and 20% chromium. Said channel members 70 are arranged in parallel relation with their open sides extending away from the combustion chamber, and the adjacent edges of said channel members 70 are welded to one another as indicated at 72 in Fig. 4; angle members 74 of the same material are provided at each side of the series of channel members 70, and these angle members 74 are welded to the adjacent channel members as shown and to the bottom portion 12 as indicated at 76. Fig. 3 shows in plan how the channel members 70 and angle members 74 form the plate portion 69 which is a part of the cover or bottom portion 12 of the soot-consuming device. As hereinafter explained, the flaming gases from the fuel burner 16 impinge on this plate portion 69 and are deflected by it into the combustion chamber 14 in the soot-consuming device.

With the aid of Figs. 1 and 5, the novel manner in which a flame electrode is mounted in the soot-consuming device will now be described. In Fig. 5, the flame electrode is shown as comprising a rod80 of suitable heat-resisting and current-conducting material which is mounted in and projects through a sleeve 82 of insulating material such as porcelain. Secured to the porcelain sleeve 82 is a metal spider having a hub portion 84 from which arms 86 project. These arms 86 are provided with angularly extending ends 88 having perforations through which extend screws 90 which enter threaded holes in a flange 92 which is secured to the outer face of the side wall 46 in any suitable manner as by spot welding. It will be noted that an annular space 94 is provided between the porcelain sleeve 82 and the wall of the opening in the refractory lining 50 of the soot-consuming device; and it will also be noted that the opening through the flange 92 is of larger diameter than the diameter of the porcelain sleeve 82. Therefore, air is permitted to flow into the soot-consuming device through the annular space 94, thereby cooling the porcelain sleeve 82 which is of course subjected to heating by the flaming gases in the soot-consuming device. In this way, objectionable heating, cracking and sooting of the porcelain sleeve 82 of the flame electrode is prevented; and the rod 80 of the flame electrode is supported in the soot-consuming device in the path of the flaming gases. Experience has proved that, when the flame electrode is thus mounted in the wall of the soot-consuming device, the flame electrode functions satisfactorily to permit the passage of an electric current (in a control circuit not shown) through the rod 80 and the ionized space within the combustion chamber of the soot-consuming device to any exposed metal part such as the cover or bottom portion 12 of the soot-consuming device.

Fig. 6 shows a soot-consuming device embodying the invention, which is the same as the embodiment shown in Fig. 2 and hereinbefore described, except that the flame-deflecting plate portion 69 of a metal alloy which is oxidation-resistant at high temperatures (illustrated in Figs. 3 and 4) is replaced by a plate of refractory material 96 which may be similar to the refractory lining 50 (hereinbefore described) and is preferably reinforced by an embedded wire fabric 98 similar to the wire fabric 52 hereinbefore mentioned. The plate portion 69 (illustrated in Figs. 3 and 4) otters the advantage that it stores less heat and cools more rapidly than the plate 96 of refractory material (shown in Fig. 6); with the result that, when the supply of fuel to the fuel burner is cut off, less heat is radiated back into the fuel burner from the metal plate portion 69 than from the plate 96 of refractory material. This is desirable under some conditions. However, under other conditions, the plate 96 of refractory material will function satisfactorily.

The manner in which the soot-consuming device operates will now be described. As will be obvious from Figs. 2 and 6, and flaming gases from the fuel burner 16 enter the soot-consuming device, impinge on the metal plate portion 69 (of Fig. 3) or on the vitreous plate portion 96 (of Fig. 6), and are deflected into engagement with the deflector or baflie 64, and by the latter are deflectcd upwardly into the combustion chamber 14 within the soot-consuming device. The arrows in Figs. 2 and 6 (more or less roughly) indicate the path of the flaming gases through the soot-consuming device. It will be obvious that the flaming gases from the fuel burner 16 are caused to flow in a tortuous confined path through the soot-consuming device and that they repeatedly impinge on the refractory material with which the major portion of the soot-consuming device is lined. Therefore, any soot particles which may exist in the gaseous products of combustion are brought into contact with the hot vitreous lining and are consumed within the chamber 14 of the soot-consuming device before said gases leave it through the exit opening bounded by the flange 62. For that reason, substantially soot-free gaseous products of combustion are delivered from the soot-consuming device, and any danger of the deposit of soot from those gases, however they may be employed, is substantially eliminated.

What is claimed is:

1. In a heater, a fuel burner, a soot consuming device comprising a box having side and end walls and top and bottom portions cooperating to provide a combustion chamber of length substantially equal to normal gas flame length, said box having a lining of thin cast refractory material, one part of said top portion at one end of said box comprising a plate inclining outwardly and downwardly at an acute angle to said bottom, said plate having an entrance opening to said combustion chamber, a deflector of refractory material extending from said bottom portion into said combustion chamber, said bottom portion having on one side of said deflector and immediately adjacent thereto an exit opening and on the other side of said deflector and immediately adjacent thereto a flame-deflecting plate which is located opposite to and in the path of gases entering the combustion chamber through said entrance opening in said first-named plate, said burner being mounted on said box above said entrance opening with its axis normal to said first-named plate and extending into said entrance opening and directed to discharge flaming gases through said entrance opening onto said flame-deflecting plate whereby the flaming gases and other products of combustion from the fuel burner entering said combustion chamber through said entrance opening impinge on said plate and are deflected therefrom into said chamber and flow therethrough turbulently in a tortuous confining path and impinge on the refractory material of said deflector and box portion on their Way to said exit opening.

2. A soot-consuming device according to claim 1 in which said flame-deflecting plate of said bottom portion is made of thin cast refractory material similar to the lining of said box portion.

3. A soot-consuming device according to claim 1 in which said flame-deflecting plate of said bottom portion is made of an oxidation-resistant metal.

4. A soot-consuming device according to claim 1 in which said flame-deflecting plate of said bottom portion consists of a plurality of channel members made of an oxidation-resistant metal which are secured to one another in parallel relation with their open sides extending outwardly.

5. A soot-consuming device according to claim 4 in which said channel members are secured to one another by welding at their adjacent edges.

References Cited in the file of this patent UNITED STATES PATENTS 234,395 Dickey -3 Nov. 16, 1880 326,161 Selwyn Sept. 15, 1885 348,700 Stevens Sept. 7, 1886 608,161 Sotolongo July 26, 1896 1,341,294 Breeding May 25, 1920 1,341,299 Copland May 25, 1920 1,654,403 Blake Dec. 27, 1927 1,764,528 Rutter June 17, 1930 1,795,832 Cannon Mar. 10, 1931 2,083,493 Herbert June 8, 1937 2,157,643 Westwick May 9, 1939 2,172,399 Mueller Sept. 12, 1939 2,286,719 De Muth June 16, 1942 2,296,392 M-archant Sept. 22, 1942 2,302,859 Hare Nov. 24, 1942 2,376,140 Henderson et a1. May 15, 1945 2,396,146 Atwater Mar. 5, 1946 2,420,875 Frentzel et a1 June 20, 1947 2,448,497 Rosche Aug. 31, 1948

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