US2431460A - Boiler and hot-water heater - Google Patents

Description

Nov. 25, 1947. L. E. BURKHART BOILER AND HOT WATER HEATER Filed Dec. 27, 1945 s sheets-sheet 1 T I I l I f [I- I NOV. 25, 1 E BURKHART BOILER AND HOT WATER HEATER Fild Dec. 27, 1945 3 Sheets-Sheet 2 1947- L. E. BURKHART BOILER AND HOT WATER HEATER 3 Sheets-Sheet 3 Filed Dec. 27, 1945 Patented Nov. 25, 1947 UNITED STATES PATENT. OFFICE BOILER AND HOT-WATER HEATER Loris E. Burkhart, Peabody, Mass. Application December 27, 1945, Serial No. 637,324

7 Claims. 1

This invention relates to boilers of the so-called vertical tubular type.

It aims to devise a boiler of this general character in which the advantages of this type will be obtained in a structure which can be manufactured more economically than can the orthodoX forms of tubular boilers. It is a further object of the invention to provide such a construcion which will be exceptionall efiicient; in which steam can be generated from a cold start more quickly than in the prior art boilers of this type; and which will deliver dry superheated steam without pressure.

The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

In the drawings:

Fig. 1 is a plan view, partly in section, of the main body of a boiler, with the smoke chamber removed, embodying this invention;

Fig. 2 is a vertical, sectional view, taken substantially on the line 22, Fig. 1;

Fig. 3 is a plan view on a smaller scale showing the smoke chamber;

Fig. 4 is a vertical, sectional View, taken approximately on the line 44, Fig. 3;

Fig. 5 is a plan View of one of the baffle devices used in the fines, part of the cover being broken away; and

Fig. 6 is a side elevation of one of said bafiles, a part of the cover being shown in section.

Referring first to Figs. 1 to 4, the structure there shown comprises a boiler casing or shell 2, preferably of rectangular form, both in horizontal and in vertical section. A crown sheet 3 divides the space in said casing into a combustion or furnace chamber 4, and a combined water and steam chamber 5. As shown, an aperture 6 is provided in the wall of the combustion chamber to receive the muzzle of a gun-type oil burner, but the source of heat used can be varied to suit the requirements of individual uses and installations.

In the water and steam chamber the water line normally will be at about the level indicated at W-W in Fig. 4, but this space is divided by right and left partitions 1-4 into a relatively and narrow small central space, and two laterally disposed larger spaces. These partitions 'l1 extend from the front vertical wall of the casing to the rear wall but, preferably, are not welded to either wall. Their lateral relation to the side walls is best shown in Fig. 4. From an inspection of this figure it will be seen that the lower edges of the two partitions are located closely adjacent to, but are spaced from, the side walls, and the partitions extend inwardly and upwardly toward the center of the boiler; next rise ver- 2 tically, parallel toeach other, to a point above the normal water line; and theneXtend-outwardly away from each other almost-to. their. respective side-walls.

Thus these partitions divide the body of water in the casing into a central, relatively small, sec-. tion, and two larger reserve supply sections-contained within the partitions l e-.7. In fact, these partitions cooperate with the adjacent side lateral walls of the shell 2 to form chambers or tanks holding the reserve supply of water and maintaining them approximately isolated or segregated from the smallercentral body. This central section, however, receives thegreater part of the heat because it is directly in contact with the crown sheet 3, and it, isin this section, there-. fore, that the steam is generated.

Heat is also supplied to: the steam and water sections by a series of fines 8. which extend upwardly from the crown sheet through both the steam generating and reserve water supply spaces; through the steam dome above the partition 'i-'l; and into the smoke. chamber min the supplemental: casing l2 secured to the top plate of the body of the boiler. Certain of the fines, or at least one of. them, extend closely adjacent to the substantially vertically extending walls which di-. vide the reserve water chamber from the vertical part of the steam generating section. At least one of the lines 8 may actually form a part of oneof these vertical walls. Whether the flue forms part of a vertical wall or whether it lies against the vertical wall of the steam section is immaterial so long as at least one of the fines, and preferably-a plurality of them, lies in such position with regard to the steam generating section as to provide a direct heat transfer from the flue or fines to the steam generating section. All of the products of combustion find their escape through these fiues and outthrough the pipe con: nection is to the stack. A removable cover 14 for the casing l2 normally closes the top of it and is equipped with a handle I5.

Steam flows from the steam dome in the boiler through one orboth of the outlets Ill-J6, Figs.

3 and 4, to the heating system, orother apparatus in which it is used, and the water of condensation is led back into the boiler at the inlet l1, Fig. 4. Near the opposite edges of the crown sheet, and just above it, clean-out openings Ill-I 8 are provided and are normally closed by removable plugs.

Referring more particularly to Fig. 4, it will be seen that when this apparatus is operated as a steam boiler, only the small central portion of the entire body of water in the boiler is in contact with the crown sheet, and therefore it is heated'to a much higher degree than are the reserve bodies of water inthe lateral tanks formed by the partitions i -11. When starting up with the boiler cold, steam can be generated from this central body of water in a very short period of time. And, as the boiler continues in operation, the steam supply still comes from this central segregated body of water, the main part of the circulation affecting only this small body. At the same time the reserve supplies of water are always in communication with this central body through the narrow spaces a-a between the extreme lower edges of the partitions 'i'--1 and the adjacent surfaces of the boiler shell. An automatic gravity flow of water from these reserve supplies therefore takes place as required to replenish the central steam generating body of the water. The fact that the spaces in which this reserve supply is held are vented at the points 12-42, Fig. 4, facilitates such flow. However, the further fact that only a small body of water must be kept heated to a temperature sufficiently high to generate the required flow of steam contributes materially to economy of operation.

In order to increase the amount of heat absorbed from the hot gases flowing through the flues 8, baffles, preferably of the type best shown at 20 in Figs. and 6, are loosely and removably positioned in them. Each baffle includes a strip or plate of sheet metal 2|, arranged in a zig-zag formation and having stay rods 22 welded to it to hold it in the desired shape. A slotted cover also is Welded to its upper end and is provided with a handle 23. The body portions of these baflles are spaced slightly from the walls of the flues 8 so that they tend to guide the flue gases in zig-zag path, and they serve to retard the rate of flow of these hot products of combustion through the flues and thus produce a better transfer of their heat to the walls of the flues. Also by more or less concentrating the baffling efiect near one end or the other of the flue, the distribution of heat lengthwise of the flue can be predetermined, as desired, to supply more of it to the water or to the fluid in the steam dome, as necessary to suit the requirements of different operating conditions. This may be done, for example, by making changes in the shape or clearance of the body of the baffles so that the rate of flow of the gases is slower in some portions of the flues than in other parts of them. The flue gases escape through holes in the cover plates, one of these holes being shown at in Fig 5.

Use is made of this feature when it is desired to deliver dry and moderately superheated steam to the steam supply line or lines. Referring to Fig. 4, it will be seen that, as steam comes from the small central body of water, it flows past, and in contact with, those portions of the flues 8 which extend through the steam dome and thence flows to the outlets iii-I6, but it is protected by the partitions 'l| from coming in contact with the bodies of reserve water in the tanks formed by said partitions and the casing. Consequently, by designing the bafiles or retarders 20 in the manner above described so that more of the heat of the circulating gases will be dissipated in these upper sections of the flues, their temperature in the steam dome can be maintained considerably above that of saturated steam, and thus the temperature of the outgoing steam will be raised to a value substantially higher than that of saturated steam. This fact has been demonstrated in actual practice, and this result can be obtained without operating the system under any substantial degree of pressure.

The reserve supply of waterin the lafitral tanks is normally maintained at a temperature close to the boiling point of water so that, as it is fed very slowly into the central steam generating space, no material change in temperature of the water in that space is produced by such flow. The fact, however, that there is normally no substantial circulation of water in this reserve supply, that steam is not being generated in it, and the latent heat of vaporization, therefore, is not being absorbed at any substantial rate from this body, means that the delivery of heat to it is relatively small, as compared to that transmitted to the smaller central body of water from which steam is being generated in volume.

When this apparatus is used as a hot water heater, then the entire space in it above the crown sheet is filled. In starting up with the heater cold, a thermally-induced circulation takes place throughout the entire body of water, including that in the lateral reserve supply tanks. This continues until the whole body is heated to a temperature usually predetermined by the circulating control apparatus customarily used in these systems. When that point is reached the circulating pump is cut in, and then a forced circulation of hot water throughout the system is produced and is maintained until the pump is again out out. The circulation so created through the boiler, however, is confined mainly to the central space where, in a steam installation, the steam is generated. Relatively little of this flow goes through the reserve supply tanks. Consequently, the advantage of confining the application of heat mainly to the body of water in actual circulation through the heating system is obtained here, as in using the same apparatus for generating steam, and the advantages produced in the latter case are also obtained when the boiler is used as a hot water heater. For this reason the apparatus has been herein referred to as a boiler, this term being used in a generic sense to cover either use made of it.

Suitable apertures may be provided in the shell or casing to receive the instruments commonly used with it. For example, a safety valve, or equivalent device, may be connected into the casing at the point 25, Fig. 1, and a pressure or temperature gauge may be installed at the point 26.

It will be observed that this construction lends itself to convenient manufacture from boiler plate cut into sections of proper sizes and shapes to be welded together. With proper equipment these cutting and welding operations can be performed rapidly and economically, most of the pieces being of rectangular form. In the particular construction shown, the flues 8 may be made in the same manner, but usually are prefabricated, and they are welded to the parts of the partitions through which they extend, this assembly of flues and partitions being later welded to the crown and top sheets, and all of these parts then being installed in the shell before the bottom is applied. The top and bottom then are welded to the side plates.

While I have herein shown and described a preferred embodiment of my invention, it will be evident that the invention may be embodied in other forms without departing from the spirit or scope thereof. For example, in some installations it may be desirable to make the reserve water space surround more of the central steam generating area than in the construction shown.

This, and other modifications, however, can be made without departing from the spirit or scope of the invention.

The term steam generating section in the claims includes the chamber whose lower wall is defined by the crown sheet 3, the inwardly inclined Walls 7 and vertical walls extending from them, the space above the vertical walls being open so that steam generated in this section may pass through into the steam dome or chamber 5.

Having thus described my invention, what I desire to claim as new is:

1. A boiler structure comprising a vertical casing provided with a furnace section and a water and steam section above it, a crown sheet separating said sections, partition walls dividing the water and steam section into a central steam generating section and reserve water chamber means, said chamber means at least partially surrounding said steam section, said walls extending from points adjacent the junction of the opposite sides of the casing with the crown sheet inwardly and upwardl toward each other to the central portion of the casing and then upwardly to the upper part of the space in the casing to define said steam generating section, but then extending outwardly away from each other approximately to the opposite sides of the casing, the said steam generating section being approximately isolated by said inclined and upwardly extending walls from said reserve water chamber means, the said outwardly extending walls being spaced vertically from said casing to provide a steam dome in which steam is approximately isolated from the top of said water chamber means, means permitting the restricted flow of reserve water from said chamber means into said steam generating section, a series of flues extending from said furnace section up through said crown sheet and through said reserve chamber means and ,said steam dome, and at least one of said flues lying in such position with regard to the steam section as to provide a direct heat transfer from said last mentioned flue to the steam generating section.

2. A boiler structure comprising a vertical casing provided with a furnace section and a water and steam section above it, a crown sheet separating said sections, partition walls dividing the water and steam section into a central steam generating section and reserve water chamber means, said chamber means at least partially surrounding said steam section, said walls extending from points adjacent the junction of the opposite sides of the casing with the crown sheet inwardly and upwardly toward each other to the central portion of the casing and then upwardly to the upper part of the space in the casing to define said steam generating section, but then extending outwardly away from each other approximately to the opposite sides of the casing, the said steam generating section being approximately isolated by said inclined and upwardly extending walls from said reserve water chamber means, the said outwardly extending walls being spaced vertically from said casing to provide a steam dome in which steam is approximately isolated from the top of said water chamber means, means permitting the restricted flow of reserve water from said chamber means into said steam generating section, a series of flues extending from said furnace section up through said crown sheet and through said reserve chamber means and said steam dome, and at least one of said flues lying against the upwardly extending walls of said steam generating section.

3. A boiler structure comprising a vertical casing provided with a furnace section and a water and steam section above it, a crown sheet separating said sections, partition walls dividing the water and steam sections into a central steam generating section and reserve water chambers at opposite sides of the central steam generating section, said walls extending from points adjacent the junction of the opposite sides of the casing with the crown sheet inwardly and upwardly toward each other to the central portion of the casing and then upwardly to the upper part of the space in the casing to define said steam generating section, but then extending outwardly away from each other approximately to the opposite sides of the casing, the said steam generating section being approximately isolated by said inclined and upwardly extending walls from said reserve water chambers, the said outwardly extending walls being spaced vertically from said casing to provide a steam dome in which the steam is approximately isolated from the top of said water chambers, means permitting the restricted flow of reserve water from said chambers into said generating section, a series of flues extending from said furnace section up through said crown sheet and through said reserve water chambers and said steam dome, and certain of said flues lying in such position with regard to the steam generating section as to provide a direct heat transfer from said flues to the steam generating section.

4. A boiler structure according to preceding claim 1 in which said flues are of approximatel rectangular form in horizontal section.

5. A boiler structure according to preceding claim 3 in which said flues are of approximately rectangular form in horizontal section.

6. A boiler structure according to preceding claim 1 in which said flues are of substantially rectangular form in horizontal section, said flues being relatively wide but narrow in horizontal dimensions, and baffles in certain of said flues whereby to increase the rate at which heat is transferred from the fluids in said flues to the fluids outside of them and which are in thermal relation thereto.

7. A boiler structure according to preceding claim 3 in which said flues are of substantially rectangular form in horizontal section, said flues being relatively wide but narrow in horizontal dimensions, and bafiles in certain of said flues whereby to increase the rate at which heat is F transferred from the fluids in said flues to the water in said steam section and to the steam in said steam dome.

LORIS E. BURKHART.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 547,045 Sturtevant et al. Oct. 1, 1895 835,749 Connor Nov. 13, 1906 1,859,745 Morley May 24, 1932 1,885,040 Arnold Oct. 25, 1932 1,993,674 Larsen Mar, 5, 1935 2,069,693 Barrett Feb. 2, 1937

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