US1983649A - Boiler construction - Google Patents

Description

G. WELTER LER CONSTRUCTION Dec. 11, 1934.

Filed Sept. 20, 1932 2 Sheets-Sheet 1 INVENTOR BY 6057/1145 WEJER 9 Z ATTORNEY Dec. 11, 1934. G WELTER BOILER CONSTRUCTION 1932 2 Sheets-Sheet 2 Filed Sept. 20

IN VEN TOR 6 1/5 7/1 v5 WA'L TM 9 712 A TTORNEYS Patented Dec. 11, 1934 PATENT OFFICE BOILER CONSTRUCTION Gustave Welter, New Haven, Conn., assignor to The Bigelow company, New Haven, Conn., a corporation of Connecticut Application September 20, 1932, Serial No. 633,943

6 Claims.

This invention relates to an improved boiler construction. The improvement as shown in its preferred form is particularly designed for electrically heated boilers adapted for use on railroad trains. When electric engines are used to draw a string of passenger cars, steam heat is wanted for the cars. A steam boiler can be carried in the electric train, heated by electricity, and the steam sent through the ordinary car heating pipes. This is the specific use for which the boiler shown in the drawings is designed and to which my improvement in its first embodiment was adapted. While I will describe the improvement in connection with a boiler for such use, I wish to point out that it may be applied in other specific and analogous situations.

An improved feature of the boiler is in the means by which a controlled circulation of the water is maintained under diflicult requirements. For example, a boiler mounted in an electric train as an accessory apparatus is subject to requirements not met in ordinary stationary situations. There is the question of space limitations and the movements of the train to be considered.

Among the various features of the invention are those that are related to this problem of adapting the boiler for train use.

Other features not particularly related to train use will be disclosed and claimed.

In the drawings,

Fig. l is an. elevation of a cylindrical boiler (with some interior parts shown dotted and insulation only indicated) to which my invention has beenapplied in one specific form;

Fig. 2 is a section on line 22 of Fig. 1, but to avoid mere duplication only a few of the many interior parts of the boiler are shown;

Fig. 3 is a detail view of parts only indicated by dotted lines in Fig. 1 and by section in Fig. 2; and

Fig.4 is a cross-sectional view on line 4-4 of Fig. 3. I p

Without intending to limit the invention in all particulars to a preferred form chosen for illustration I will describe in detail the specific embodimentof the drawings.

The boiler is made up i a heat insulated cylinder 1' having top and bottom flanged header members 2 and 3. A manhole 4 safety valves 5, handholes 6, level indicator 7, steam pipe connection 8, and water feed valves 9 are indicated, but form no feature of invention.

' The bottom of the boiler has a suitable flange construction 10 for solid but easily removable base connection with the floor ofthe electric engine.

The top flange 2 of the boiler shell provides a mounting in the embodiment shown for one hundred and forty heating elements 11. Each of these is mounted to be removably supported as indicated by dotted lines in Fig.1. They each eX- tend between the top and bottom headers 2 and 3, being screwed in at the top with an end casting 12 at the bottom having a socket to receive the centering stud (mounted as a pin in the bottom header, see Fig. 1) from which the heating 1 element can be lifted when unscrewed at the top header. The electric heating element per se forms no part of this invention. A suitable type is indicated and the plan of heating by electric resistance will be clear. The U-shaped wire for this 315 resistance is indicated as all below the water level W-W of the boiler, which can be arranged to correspond with any of the three valves 9. The heating element above the water level is no part of the active heating surface. It consists in any suitable support 13 having electric connections to the active part or wire below the water level. The arrangement in the boiler of the large number of heating elements (see the arrangement in Fig. 2) makes a combination with other means which I will describe with respect to a feature of the invention.

If the water were heated by the elements 11 in the boiler so far described, there would be no general or controlled, or definite circulation of v the water so as to brush against the active heating elements 11 in a desired manner for efficient heat transfer. The electric heat would set up a turbulent condition of the water. The movement would be haphazard and uncontrolled. And this would create a condition whereby some of the heating elements 11 might not have proper contact with the water to effect proper heat transfer, which would result in the heating elements being over-heated, causing rapid deterioration of these elements.

To provide a novel means for accomplishing the controlled circulation of the water in the boiler and to avoid the objectionable turbulence in the particular situation I have made a special construction as follows: Referring to Fig. 2, a large number of braces 14, extending between the top and bottom header members (see Fig. l) are each arranged adjacent a set of heating elements. In general each brace is closely surrounded by six spaced heating elements. Of course other similar arrangements can be made but the one shown works well according to the mode of operation that will be made clear below. A tube 15 for circulation is conveniently mounted, concentric with each brace. As shown in Figs. 1 and 3, the tube may rest on the bottom header member (or be held by a spider or collar to the brace independently of the bottom member) and be centered there by a collar 16 on the brace. At this lower end the tube is provided with four spaced vertical slots or notches 1'7 for :bottom openings to the interior of the tube, but if held by the brace above the bottom header, these slots are not required. At the top the tube is centered and held by a spider, 18 that may be attached to brace by a clamping collar or set screw. This provides top openings so a circulation of water as indicated by one line of arrows in Fig. 3 is possible and alike circula-p tion through each of the four slotted openings at the bottom of the tube. The top openings of the tube are below the waterline (see Fig. 1)

and preferably at about the level on which the top of the active part of each heating element is positioned."

- As the water isheated'by the heating elements,

steam bubbles form. Water then rises with the bottom of the boiler so as to repeat the cycle.

The distribution of these circulating tubes in combination with sets of heating elements grouped: around them is shown in Fig. 2. In that figure only one segment of the arrangement is shown complete, but it should be understood that the same arrangement is made in the other segment to fill the boiler shell 1. The latter figure, together with the detail in Figs. 3 and 4, makes it clear that a very large number of controlled circulating paths can be set up in the boiler operation by applying the principle of the construction disclosed.

The result is that along the length of each heating element 11 an active flow is induced to brush that element for the best heat exchange and for a rapid controlled recycling of all imvaporized water, resulting in all heating elements being equally active and cooled; thus prolonging their life. The remarkable degree to which this takes place will be seen from a consideration of any of the boiler portions such as at the spot marked X in Fig. 2. The six heating elements chosen in this spot or portion set up six paths to return through tube on the brace around which the six are grouped, and the same six elements set up twelve other paths to return through the six tubes arranged around and spaced slightly from that part of the surfaces of the same heating elements which do not face the tube encircled by such elements. And so on through the volume of the water being heated one can find many more separately controlled substituted for the electrical heating elements in such a vertical boiler as shown. They could be positioned where the electrical heating elements are now shown. The brace rods and circulating cylinders could be left as they now are or the cylinders mounted in some other suitable manner without the brace rods. Of course the fire tubes 'would need a furnace element; "These suggested substitutes are sonwell knownastoneed no drawing.

v It is ordinarily advisable but not necessary in all instances to arrange the size of the circulating tubes so that the volume of the water and steam bubbles in the rising paths of the boiler is slightly larger than the volume of the water alone in the paths-(within'the tubes) which return to the bottom of the boiler. This is a matter that can be calculated 'for each particular boiler. The definite relation of these flow areas, one up and the other down, is one that may desirably vary in different boiler designs and such variation is intended to be included in this disclosure without particular limitations.

The boilerconstruction of this invention in its broadcast aspects may be incorporated in other types of boiler shells than the simple cylindrical one shown. But the one shown lends itself particularly well to the objects of a pressure unit for a vertical boiler where space limitations are met in the specific use for which my first embodiment of the invention'is intended. That is one to be carried on an electric locomotive. There is the advantage in the specific form shown, as distinguished from other forms of The cyshells in the following considerations. lindrical shape having its header members braced by the vertical tie rods, gives 3 great bursting strength. Then the distribution of the vertical tie rods or braces corresponds to my desired distribution of circulating tubes and their relation to the large number of heating elements. And one result of this is that the construction and placing of my circulating tubes in the combination can be accomplished in a most economical manner. The tie rods serve two purposes; They brace the shell and they position the circulating tubes. The very large number of heating elements and tie rodswith circulating tubes helps stop the wash of boiler water due to locomotive movements.

While I have indicated that a circulating tube is telescoped over each brace rod, this is not necessary. Some of the rods adjacent the cylindrical wall may havethe tubes-omitted. My

intention is to indicate the main idea of the arrangement rather than a necessarily complete sible part of the boiler. I l v I am aware that in vertical boiler constructions, means have before been used to control the path of the hotwater ri'sing'and colder water falling in theboiler. The present invention consists in the "particular combinations of boiler construction by which the water Paths are controlled in a particularly desirable manner with relation to the heating-elements. These combinations in their various'broadand specific aspects are.pointed outf and'defined in the claims.

I claim asfmy invention; v

1. In a vertical boiler construction of the type having a large group of vertical heating elements distributedin spaced relation within the water space for heat transfenthe combination of means to control the flow of water along the heating elementspsaidmeams consisting in a plurality of open ended circulating tubes each of which is positioned in the water space, adjacent a small set of the heating elements, and in position far enough away from the heating units to serve as a return path for water that rises in contact with the heating elements of its set, frees its steam bubbles at the water level and is ready to return to the bottom of the boiler, said tubes having their bottom openings close to the bottom of the water space and their top openings substantially below the boiler water level, said tubes being distributed over the boiler space in suflicient number to serve substantially all of the heating elements in controlling the circulation past said elements.

2. In a vertical boiler construction the combination of a group of open ended vertical tubes spaced with substantial uniformity in the water space of the boiler and each mounted with its bottom opening near the bottom of the boiler and its top opening near but substantially below the water level and around each such tube a set of vertical heating elements spaced from each other and from such tube, the heating elements forming means to cause rising paths of water on the outside of each tube and each tube forming a common means for water to return from the rising paths nearest the tubes to the bottom of the boiler to be recirculated.

3. In a vertical boiler construction the combination of a plurality of open ended tubes vertically mounted and wholly in the water space with their bottom openings near the boiler bottom and their top openings substantially below but near the water level, each tube being outside of and spaced from the others, there being a suflicient number of tubes distributed in the boiler to form a large number of independent paths for returning water from the top to the bottom of the boiler with substantial uniformity and a plurality of vertical heating elements in the boiler arranged in sets about each of such tubes to cause the water to rise outside of the tubes and displace water at the top of the boiler for return through the tubes.

4. A vertical boiler construction comprising in combination a shell, a large number of vertically mounted individual heating elements for heat transfer to the water, a large number of water circulating tubes open at top and bottom and vertically mounted to extend from the bottom of the water space to a point near but below the water level, the number of heating elements far exceeding the number of said tubes, each of the latter forming a central axis for a uniform spaced grouping of several heating elements about such tube, the spaces between the heating elements and between the heating elements and the tubes being very small compared to a crosssectional dimension of the shell, said arrangement of heating elements and tubes being such as to substantially fill the boiler in cross-section below the water level whereby the heated water is induced to rise with substantial uniformity outside of the tubes, release its steam and return to the bottom of the boiler through the inside of the tubes for reheating.

5. A vertical boiler construction comprising a cylindrical shell having top and bottom header members, a large number of vertical brace rods connecting the header members for uniform resistance to the bursting strain, a series of vertical heating elements arranged in groups, each one spaced about a brace tie as a center, a water circulating tube arranged on each brace rod and serving as a water circulating control for the heating elements grouped around such tie rod, said tubes opening at the bottom of the boiler and at the top but substantially below the water line.

6. A vertical electric boiler comprising a shell, a plurality of spaced and independent electrical heating elements mounted vertically in the shell to procure an exceedingly large production of steam compared to the size of the boiler, and a plurality of water circulating tubes vertically mounted in the boiler below the water level to receive the water when it releases its steam near the water level and return it solely by gravity to the bottom of the boiler for reheating by the heating elements, the latter being grouped about said tubes with substantial uniformity and in sets of several heating elements to each tube said sets of heating elements and their associated tubes being in as large a number of groups as the space of the shell will permit.

GUSTAVE WELTER.

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