US3435807A - Boiler - Google Patents

Description

April l, 1959 R. TELLlEz-METADIER 3,435,807

BOILER Filed may 22, 1967 sheet Z of 5 /fmanfa ff:

United States Patent Office 3,435,807 Patented Apr. 1, 1969 3,435,807 BOILER Raymond Telliez-Metadier, Paris, France, assignor to Decauville S.A., Paris, France, a French body corporate Filed May 22, 1967, Ser. No. 640,286 Claims priority, applicion France, May 23, 1966, 4

71 Int. Cl. F2211 7/04, 31/02 U.S. Cl. 122-136 10 Claims ABSTRACT F THE DISCLOSURE The present invention relates to boilers or heat generators of the type having a cylindrical furnace and concentric annular water jackets.

The object of the invention is to provide such a boiler having improved performance characteristics and which operates more reliably and more conveniently as compared with conventional boilers.

The invention has for its object a boiler of the aforementioned type, comprising two burners positioned facing one another, each at an end of the cylindrical furnace, and at least two water jacket means positioned concentrically around the furnace and defining an annular gap between them, the water jacket means adjacent to the furnace comprising at least a pathway connecting the furnace with said annular gap.

According to an embodiment of the invention, the water jacket means closest to the furnace comprises two half-jacket means, which extend coaxially `and which are separated by an axial gap constituting said pathway.

Because of this face to face position of the burners, there results a perfectly balanced combuston throughout the furnace and an improved performance of this combustion due to the formation of a turbulence area in the mean portion of the furnace in which both gaseous streams from the burners become mixed together.

According to the preferred embodiment wherein the water jacket means adjacent to the furnace is provided as two portions, it is in this turbulence area that the annular gap separating both half jacket means is located, gap through which the hot gases may pass from the furnace into the annular gap comprised between the inner water jacket means and the adjacent concentric jacket means.

Thus, in the generator according to the invention, there is provided a strictly symmetrical path for the combustion gases and the liquid heat vehicle, water, in the present case.

One example of the present invention is illustrated in the accompanying drawings wherein:

FIG. l is a sectional longitudinal view of a boiler according to the invention;

FIG. 2 is a cross-sectional View of this boiler along line 2*-2 of FIG. 1.

FIG. 3 is a cross-sectional view of a modification of the boiler.

The drawing illustrates in somewhat simplified fashion a boiler according to the invention, comprising a shell or cylindrical jacket of X-X axis resting on a support consisting of foundations 2.

The cylindrical shell 1 contains a lagging 3 and both its ends are closed by doors 4 having a refractory lining 5 and hinged on the shell by joint means 6- The elements 1-5 constitute the case of the boiler.

In each door 4 there is incorporated a burner B of known type which, therefore, will not be described in further detail. Both burners B are positioned face to face, coaxially with respect to the cylindrical shell 1 and to the furnace F of the boiler.

This furnace is defined by inner shell ring 7a of two identical water half-jacket means or chambers 7 extending coaxially and separated by an axial annular gap 8.

Said half-jacket means consist of inner shell rings 7a and outer shell rings 7b.

Two other water jacket means 9 and 10 are positioned concentrically with respect to both half-annuli 7.

Jacket means 9 is provided as two identical annular chamber assembled in the median part of the boiler by means of flanges 11 secured by means of bolts 12 and nuts 13. This jacket means also comprises inner shell rings 9a and outer shell rings 9b.

Outer water jacket means 10 comprises, like the other water jacket means, two identical annular chambers secured together by a flange 14 and comprising inner shell rings 10a and outer shell rings 10b.

The water jacket means are separated by spaces 15 (FIG. 2) and define successive annular gaps 16, 17 through which the gases resulting from the combustion in furnace F may circulate. To obtain optimum path of the gases through said annular gaps, the connecting pathways between such gaps are alternatively provided in the mean portion of the boiler and at the ends thereof.

The existence of pathway 8 between both half-jacket means 7 has already been indicated. The following halfjacket means 9 are sealed at the mean portion, however an annular pathway 18 is provided between them and the respective end doors 4, In addition, sealing beads 19, 20, which cooperate with inner shell rings 7a and with outer shell rings 10b of water annuli 7 and 10 are provided in each of these doors.

The boiler is provided with means for supplying, circulating and evacuating water and gas; said means comprise -a double inlet or recycle tubing 21 for the water, which is positioned at the bottom of the boiler; the successive water jacket means communicate through tubular pathways 22, 23 with the inlet and 24, 25 with the outlet, respectively.

The water inlet conduits open at 21a in inner water jacket means 7 which requires the higher irrigation; the water passes then into the other jacket means, through pathways 22 and 23. It is to be noted that connecting pathway 22 is wider than pathway 23 provided between both outer jacket means.

Outlet conduits 26, 27 are positioned at the top of the boiler, facing pathways 24 and 25.

Also, draining devices 2S are provided at the bottom of the boiler, for each half thereof.

The discharge of the combustion gases, after these have passed through the various portions of the boiler provided for this purposes, is effected at the top of the boiler, by means of flue 29, secured to flange 14 which defines an annular collector 30` for combustion gases. At the bottom portion of this flange a soot receiver 31 is provided.

The operation o-f such a boiler is the following: ventilation of both burners is first started simultaneously, and the delayed firing up of said burners is then effected, i.e., both burners are not fired up at the same time. This precaution is intended to avoid potential deflagration and also to attenuate the thermal shock which occurs at the time of firing.

In operation, both burners provide a gas jet, both jets meeting in the mean portion of furnace F. This creates in this area a turbulence which contributes to the production of a particularly high combustion performance. Under the action of the pressure within the furnace, the hot combustion gases escape radially in all directions through gap 8 defined by both water half-jacket means 7, and How into annular gap 16 between 'water jacket means 7 and adjacent water jacket means 9.

The combustion gases cool down gradually while transferring heat to the water circulating in the water jacket means, such heat transfer occurring primarily by radiation; then, they pass through gap 17 between both outer water jacket means 9 and 10, passing, at 18, round the edges of water jacket means 9.

From there, they are collected into annular pathway 30 and are withdrawn through ue 29.

It is to be noted that the path of the hot combustion gases is strictly symmetrical, both with respect to a longitudinal vertical plane along axis X-X of the boiler, and with respect to a median plane Y-Y, perpendicular to axis X-X. This gas circulation without preferential path makes possible optimum heat transfer with the water circulating in the water annuli.

This optimum transfer is completed by the fact that the path followed by the water to be heated up is also strictly symmetrical with respect to 'both the aforementioned planes. Indeed, the water is introduced into water jacket means 7 through conduits 21a and ows either through jacket means 7 toward outlets 24, or to jacket means 9 and 10 through pathways 22 and 23.

The size of the water jacket means, the radial width of the 4free gaps between two adjacent water jacket means, the free sections of the various pathways provided for the water and the combustion gases are calculated to give a controlled circulation of both fluids, optimal heat transfer therebetween and satisfactory characteristics for both said fluids at the outlet of the generator.

In particular, in this boiler there are obtained high circulation rates which have the advantage of substantially avoiding any deposit of scale or soot and, in addition, serve to prevent localized superheating. However, the gas circulation rate is slowed down in annular gaps 16 and 17 to facilitate heat exchange by radiation.

The boiler according to the invention exhibits a number of most important further advantages: rst, due to its arrangement, the generator just described warms the water by the almost sole use of a radiation effect; there results a maximum heat exchange performance which adds to the maximum combustion performance due to the presence of both burners and to their face-to-face arrangement. Therefore, for a given performance, the generator according to the invention is 0f a size substantially less than that of conventional generators.

As already mentioned, the soot deposit on the outer surface ofthe walls of the water jacket means is relatively small; in fact, this deposit is not detrimental to the heat exchange by convection; the soot coating the walls of gaps 16 and 17 behaves like black bodies and abandons by conductivity the absorbed calories, to the metal surfaces of the water jacket means and to the water circulating therein. Therefore, sweeping this boiler is a secondary consideration which is by no means imperative.

An important advantage of the separation of water jacket means 7 into at least two members is due to the fact that the detrimental effects of the expansion of the metal walls dening this jacket means are reduced. Indeed, the temperature within the furnace being above 1000 C., the expansion of inner shell ring 7a is substantial, which is often the cause of fractures in conventional boilers, especially at the level of the welds. In contrast, in the generator according to the invention, the effects of expansion are applied only to members having a length at most equal to half the total length of the boiler.

It should be noted also that the boiler as a Whole exhibits a symmetry with respect to plane Y-Y and consists of identical members assembled in a simple manner in mean plane Y-Y or in the vicinity thereof. In this manner, the boiler is readily taken apart and all parts thereof are readily accessible, which constitutes an important advantage over the generators of conventional monobloc construction.

Experience has also demonstrated that operation of this generator is particularly silent, which is presumably due to the face-to-face arrangement of the bumers.

The control and actuating devices of the boiler are not illustrated in the drawing; however, it may be mentioned that an aquastat is provided on each hot water outlet conduit, each of these aquastats cutting off, when actuated, both burners B. This arrangement insures additional safety in the case where, for some reason, one of these aquastats would be unable to function.

In the embodiment of FIGS. l and 2, the concentric water jacket means have substantially the same radial width. According to the modification of FIG. 3, this width may be increased from the inner jacket means toward the outer jacket means, so as to improve heat exchange in the outer jacket means.

Also, burners B have not been described, as being known per se, which burners, `depending on the power contemplated for the generator, may have a low and a full combustion rate, this feature modifying in no way the operation of the unit. The fact two burners are provided makes also for great flexibility of use, since, when desired, only one of these yburners may be started, in case of reduced power operation.

Although a specific embodiment of the invention has been described, many modications and changes may be made therein without departing from the scope of the invention as dened in the appended claims.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

1. Boiler comprising a case, a plurality of radially spaced coaxial jacket means enclosing water spaces of annular cross section in said case, each pair of radially adjacent jacket means dening therebetween an annular gap axially substantially coextensive with the jacket means, the radially innermost jacket means radially defining a furnace and comprising gas passage means located substantially midway axially of the ends of the innermost jacket means and putting the furnace in communication with the gap between the innermost jacket means and the radially adjacent jacket means, gas outlet means putting the gap between the radially outermost jacket means and the radially adjacent jacket means in communication with the exterior of the boiler, and two burners respectively mounted in facing relation at the ends of the boiler and disposed to direct the gases of the burners toward the region of the furnace corresponding to said gas passage means.

2. Boiler as claimed in claim 1, wherein the innermost jacket means comprise a plurality of coaxial annular cylindrical water chambers of same diameter and same radial width separated by an axial circumferentially extending gap constituting said passage means of the innermost jacket means.

3. Boiler as claimed in claim 2, wherein the innermost jacket means consist of two identical coaxial cylindrical water chambers separated by one axial gap.

4. Boiler as claimed in claim 1, wherein said jacket means are arranged in two identical series of annular water chambers mounted symmetrically with respect to a median plane perpendicular to the common axis of the jacket means, and means for detachably interconnecting Said series of water chambers, said innermost jacket means comprising two water chambers which are axially spaced apart in the region of said median plane and Idene said gas passage means of the innermost jacket means.

5. Boiler as claimed in claim 1, comprising three radially spaced coaxial jacket means radially defining between them two annular gaps through which circulate the combustion gases and combustion gas passageways putting the two gaps in communication with each other.

`6. Boiler as claimed in claim 5, wherein said gas passageways for putting the two annular gaps in communication with each other are located in the vicinity of both ends of the case, the intermediate water jacket means between the innermost and outermost jacket means being continuous between said gas passageways.

7. Boiler as claimed in claim 1, comprising a boiler shell and two doors hinged on the ends of the boiler shell and in which the burners are mounted.

8. Boiler as claimed in claim 1, comprising, at the bottom part thereof, a water inlet conduit opening in the innermost jacket means, and at the upper part thereof a water outlet conduit, and connecting water passage means between radially adjacent jacket means at the lower part and at the upper part of the boiler, respectively.

9. Boiler as claimed in claim 8, wherein the connecting water passage means provided at the lower part of the boiler have respectively a passage section which decreases from the inside to the outside of the boiler from one pair of adjacent jacket means to the next pair.

10. Boiler as claimed in claim 1, wherein the radially successive jacket means have a radial Width which ncreases from the inside to the outside of the boiler.

References Cited UNITED STATES PATENTS 2,040,959 5/ 1936 Schumann 122-136 2,531,459 11/1950 Marshall 1221-136 3,162,178 12/ 1964 Vandal. 3,192,906 7/ 1965 Ger-bert 122-136 3,236,212 2/ 1966 Ospelt 122-136 CHARLES I. MYHRE, Primary Examiner.

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