US1861264A - Mercury boiler - Google Patents

Description

y 1932- a. P. COULSON, JR 1,861,264

METRCURY BOILER File d June 14. 1929 2 Sheets-Sheet 1 Fig.

Inventor Bevis I? CouJsomJ-n, v bg His Atcor'heg.

Patented May 31, 1932 UNITED STATES PATENT FFIE BEVIS P. COULSON, JR., OF SOHENECT'ADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION" OF NEW YORK MERCURY BOILER Application filed .Tune 14,

The present invention relates to mercury boilers, and especially to mercury boilers of the type disclosed in the a plication of L. R. Emmet and mysel Serial No. 306,486 filed September 17 1928.

The object of my invention is to provide a mercury boiler having an improved construction and arrangement of boiler tubes, and for a consideration of what I believe to be novel and my invention, attention is directed to the following specification and the claims appended thereto.

In the drawings, Fig. 1 is a sectional view of a boiler structure embodying my inven tion mounted in a furnace; Fig. 2 is a detail sectional view on a larger scale of the upper end of one of the boiler tubes; Fig. 3 is a detail plan view of the inside of one of the boiler drums; Fig. 4 is a transverse sectional view through one of the boiler drums, and Fig. 5 is a detail perspective view of a part of a boiler tube.

Referring to the drawings, 1 indicates a furnace in which the boiler is mounted. Any suitable fuel may be burned in it. In the present instance it is shown as being an oil fired boiler, 2 indicating an oil burner and 3 indicating the combustion chamber. The products of combustion pass vertically upward to the top of the furnace and are discharged therefrom laterally through conduit 4.

The boiler may comprise a number of units 5 each complete in itself. These units are mounted side by side in the furnace and are arranged to deliver elastic fluid in parallel through pipes 6 to a common header or drum 7 located at the forward end of the furnace. From header or drum 7 the elastic fluid is conveyed through pipes 8 to a second header or drum 9 located at the rear of the furnace. Connected to header or drum 9 is a conduit 10 through which the elastic fluid is conveyed to a point of consumption which may be, for example, an elastic fluid turbine. Only one of the boiler units is shown in the drawing, but it will be understood that the several boiler units may be alike and are mounted side by side in spaced relation to each other. They are supported in the fur- 1929. Serial No. 370,995.

nace in any suitable manner.

instance they are shown as being suspended from I-beams 11 by means of tie rods 12.

Each boiler unit comprises a casing or drum 13 which is closed at its ends by suitable heads. Depending from the under side of drum 13 are a. number of boiler tubes 14., such tubes being flared slightly relatively to each other and being arranged directly over the firebox whereby the products of combustion pass vertically over them. Liquid mercury is supplied to the boiler drum by a conduit 13a which may lead from any suitable source of supply. 136 indicates the liquid level gage for the boiler.

The boiler construction so far described is of the type disclosed in the above-mentioned application. My invention relates more particularly to an improved form of boiler tube 14 and to an improved arrangement of the tubes in the boiler drum.

Each boiler tube comprises an outer tube 15 in which is located a tubular core 16. Outer tube is closed at its lower end, being provided with a rounded bottom, and at its top it is fastened in an opening in drum 13, preferably by welding, as is indicated at 17, Fig. 2. Core 16 comprises a thick wall tube of the same general contour as the outer tube. It is held in spaced relation to the outer tube by suitable means such as a number of short longitudinally extending ribs 18 which may be formed by pressing outwardly some of the metal of the core. The lower end of the core terminates short of the bottom of the outer tube and is held in spaced relation to the bottom of the outer tube by one or more spacers or projections 19. lVith this arrangement it will be seen that the passage through the core, which passage is designated 20, communicates at its lower end with an annular passage 21 formed between the core and the inner surface of outer tube 15.

Core 16 may be formed with advantage of two spaced tubes welded together at their upper and lower ends, as is indicated at 22, the space between the tubes at the upper end being closed by a disc 22 The dead space formed in the core between the tubes is preferably filled with air, although it may be filled In the present with some other substance. The purpose of this is to provide an effective heat insulation between the passage 20 through the inner tube or core and the outer tube to prevent the transfer of heat to the liquid while flowing down through passage 20. This is important in a mercury boiler, it being essential that a large quantity of relatively cool mercury be delivered continuously to the end of the tube which is exposed to heat radiation because mercury when not boiling is a much better heat remover than it is when boiling. Pref erably the inner tube of the core has one or more bends in it, as shown particularly in Fig. 1, so as to provide a small amount of flexibility in such tube to take care of unequal expansion of the parts.

Core 16 terminates short of the upper end of outer tube 15, and located above it is a block 23, the lower end of which rests on the upper end of core 16. The outer surface of block 23 is spaced from the inner surface of tube 15 to provide an annular space which forms a continuation of passage 21, the block being held by pins or projections 24:. Block 23 is provided with a central passage 25 which flares outwardly at its upper end to provide a sort of funnel shaped opening 26. At its lower end, passage 25 communicates with down tube passage 20. Preferably, the pipe forming passage 20 is extended upwardly into the lower end of passage 25 so as to form a good connection between them. In block 23 are a series of circumferentially spaced slots 27 which extend longitudinally of the block from its upper end to a point short of its lower end, and in each slot are a number of partition walls 28 which slope downwardly. There is thus provided a series of downwardly sloping passages 29 which extend from the outside of block 23 to the central passages 25. Block 23 is held down preferably by means of several angle bars 30 welded to the inner surface of the upper end of outer tube 15. Preferably for manufacturing reasons the upper end of the tube 15 is formed as a separate piece, the point between the tube sections being indicated at 31. Fastened to the upper end of tube 15 is a cone shaped discharge cap 32 having a discharge opening 33 at its outer end. In outer tube 15 just inside the boiler drum is a passage 34. through which liquid mercury is fed from the drum to passage 25.

In order to decrease the space inside the boiler drum, there are provided filler blocks 35 which are arranged in rows running longitudinally of the boiler drum and are spaced apart to provide passages 36 for the flow of mercury to the tubes. The blocks are provided with recesses 37 in which the upper ends of the boiler tubes are located, the ar rangement being such that the liquid feed opening 34 of each tube opens into a passage 36. This arrangement of the blocks whereby there are provided channels for the flow of liquid to the tubes, the feed openings for the tubes communicating with the channels, is of substantial advantage in that it insures that there is always present a supply of mercury for each tube. The filler blocks are shown as being fastened to the bottom of the drum by means of bolts 38, means being provided for spacing the blocks slightly from the walls of the drum as shown in Fig. 4. Preferably each block row is made in several pieces, as shown in Fig. 3, for convenience in handling. 39 indicates a separator means which extends longitudinally of the boiler drum above the ends of the tubes and is provided with one or more openings l0 for the escape of vapor.

TVhen the boiler is in operation, mercury is fed to each tube through its feed passage 34 and flows down through central passage 25 in block 23 and passage 20 in the core to the lower end of the tube, and thence up through the annular passage 21. As it flows upward through annular passage 21 it is vaporized and the vapor and such mercury particles as are entrained with it are discharged from the upper end of vapor space 21 and directed by cone shaped cap 32 to the discharge opening 33. Mercury particles striking the cone shaped cap 32 drop downward again into the funnel shaped portion 26 of passage 25, from whence they flow down through core passage 20. Thus it will be seen that mercury is fed continuously to each core passage by way of its feed passage 34 and also from the funnel shaped end 26 of its block 23. Also, liquid mercury can flow through any of the passages 29 to the central passage 25, and more or less of the liquid particles being carried upward by the vapor are separated and returned through these passages 29 to passage 25 before the liquid particles reach the upper end of tube 15. The vapor discharged from the upper ends of the tubes strikes against the underside of plate 39 and flows along it to the discharge opening or openings 40. This serves to separate out any liquid particles in the vapor which may have escaped with it from the tubes.

It will be noted that a number of the passages 29 are located below the bottom of the boiler drum 13. This arrangement has the advantage that even should the level of mercury in the boiler drop below that of the pas- 34, still there would be maintained a circulation of mercury in the tubes due to the mercury flowing from annular passage 21 back through the lower passages 29 to the central passage 25.

By extending the tubes 15 to a point well above the bottom of the boiler drum, and feeding the liquid mercury to the tubes at a point below their upper ends, the advantage is obtained that the vapor discharged from the tubes cannot interfere with the flow of liquid mercury to the central core passages. This arrangement, therefore, serves to make more sure a continuous uninterrupted flow of liquid mercury to the tubes.

The liquid level of the mercury in the boiler drum during normal operation would be in the vicinity of the tops of the filler blocks 35 so that the mercury supplied to the tubes through the feed passages 34 enters such passages from a point well below the surface of the mercury in the boiler drum. This arrangement has the advantage that the mercury is drawn always from below the liquid level in the boiler drum so there is no danger of dirt accumulated on the surface of the mercury being drawn down into the tube.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a mercury boiler, the combination of a casing, an outer tube which projects through said casing to a point above the inner sur face of the casing wall, a core in said outer tube in spaced relation thereto to provide an up passage, said core having a passage for the down flow of mercury, means providing vertically extending slots which connect the up passage to the down passage from a point above the casing wall to a point below the inner surface of the casing wall, and means for supplying mercury from the casing to said down passage.

2. In a mercury boiler, the combination of a casing, an outer tube which projects through said casing to a point above the inner surface of the casing wall, a core in said outer tube in spaced relation thereto to provide an up passage, said core having a passage for the down flow of mercury, means providing vertically extending downwardly sloping slots which connect the up passage to the down passage from a point above the casing Wall to a point below the inner surface of the casing wall, and a conduit for con veying mercury from the casing to said down passage.

3. In a mercury boiler, the combination of a casing, a plurality of boiler tubes depending therefrom, each boiler tube comprising walls which define an outer up passage and a central down passage, the upper ends of said tubes projecting above the inner surface of the bottom wall of the casing, filler blocks in said casing spaced from each other to form channels, said blocks having recesses in their sides in which the upper ends of said tubes are located, and means providing passages which connect said channels to the down passages in said tubes.

4. In a mercury boiler, the combination of a casing, a plurality of boiler tubes depending therefrom, each boiler tube comprising walls which define an outer up passage and a central down passage, the upper ends of said tubes projecting above the inner surface of the bottom wall of the casing to a point above the normal liquid level in the boiler, cone shaped vapor discharge caps on the ends of said tubes, filler blocks in the casing which define channels for the flow of mercury, and passages connecting said channels to the down passages of the tubes.

5. A mercury boiler tube comprising an outer tube, a core in said outer tube in spaced relation thereto to provide an up passage, said core having a down passage for the flow of mercury, means providing vertically extending downwardly sloping passages in the upper end of the core directly adjacent to the admission end of the down passage which connect the up passage to the down passage, and a conduit which connects one of said sloping passages to the outside of the outer tube and through which mercury may be supplied to the down passage, said conduit being located below the upper end of the outer tube.

In witness whereof, I have hereunto set my hand this 13th day of June, 1929.

BEVIS P. COULSON, JR.

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