US1978822A - Locomotive with bifurcated flues - Google Patents

Description

first. 30, 1934. F, w $M|TH 1,978,822

LOCOMOTIVE WITH BIFURCATED FLUES Filed April 5, 1953 2 Sheets-Sheet l I y\ L i- E' J INVENTQR F'ranK W. 3 mith.

d/kvu ATTORNEY Oct. 30, 1934. F. w. SMITH LOCOMOTIVE WITH BIFURCATED FLUES Filed April 5, 1933 2 Sheets-Sheet 2 0 w Q xmwmw O owo Em D INVENTOR FranKW mLf h BY 01% ATTORNEY Patented Oct. 30, 1934 UNITED STATES PATENT OFFIQE Superheater Company,

New York, N. Y.

Application April 5, 1933, Serial No. 664,494

1 Claim.

My invention relates to boilers having horizontal fire tubes. In such boilers serious deterioration of the tube sheets occurs at times caused by high metal temperature due to insuflicient circulation along the wetted faces of the sheets. Furthermore, a low water condition is particularly serious in boilers having also an internal fire-box with crown sheet, because the crown sheet may thereby be caused to become overheated. Overheating of a crown sheet may require expensive repairs and it may also even cause the boiler to explode.

It is an object of my invention to provide an arrangement to increase the water touched area of the hotter flue sheet of a horizontal fire tube boiler having a given area of heating surface to thereby reduce the resistance to water circulation along such sheet and to increase the life of such sheet by keeping it at a lower average temperature. Another object of my invention is to provide an arrangement whereby the crown sheet of a boiler of the said type may be lowered and thereby the probability of a low Water condition be decreased. Still another object of my invention is to reduce the number of rolled joints in the flue sheets of a horizontal flre tube boiler.

In order that my invention, together with its objects and advantages, may be fully and readily understood, I will now describe in detail in connection with the accompanying drawings and by way of example a boiler selected from a number of possible embodiments of my invention. In the drawings,

Fig. 1 is a vertical sectional elevation of a locomotive in accordance with my invention, parts being omitted.

Fig. 2 is a fragmentary section on a line 2-2 of Fig. 1. I

Fig. 3 is a fragmentary section on a line 3--3 looking in the direction of the arrows.

Fig. 4 is a fragmentary section on a line 4-4 of Fig. 2.

I have shown a locomotive having a barrel 10, a combustion chamber 12, a crown sheet 14 for said chamber and a smoke box 16.

Within the barrel 10 are a number of the ordinary fire tubes 18, 18 for conducting heating gases from the combustion space 12 to the smoke box 16. At their rear ends, tubes 18 extend through and are rolled into the tube sheet 20. At their front ends the tubes 18 extend through and are rolled into tube sheet 22. It is customary at present to provide in the barrel of a locomotive enlarged smoke tubes or flues 24,

24 adapted to receive superheater units 26, 26. Flues 24 also are adapted to conduct heating gases from chamber 12 to chamber 16 and have rolled joints in the sheets 20 and 22. Certain of the flues shown as having units 26 therein are, however, of the bifurcated type, such flues having unit receiving portions 24a connected in pairs to throats 24?) which are rolled into the sheet 20. The details of the bifurcated flues seen in Figs. 1, 2 and 3, are best illustrated in Fig. 4. It will be seen that the cross-sectional area of the throats 2%, while each equal to the cross-sectional area of both the tubes 24a to which it connects, permit a greater ligament of metal between them than is provided between the tubes 24 and that the throats 24b offer less resistance to the flow of water along the wetted surface of sheet 20 than would the flues 24av if such flues were extended through the sheet 20. The arrangement shown in Figs. 1, 2 and 3 therefore not only reduces the number of rolled joints in sheet 20 but also permits a better water circulation in contact with such sheet to! both reduce the initial labor in assembling the flues and to prolong the life of the joints by maintaining the tube ends and tube sheet at a somewhat lower temperature. As illustrated, the points 28, 28 at which the throats 241) are bifurcated to form flues 24a, or flues 24a united to form throats 2412 are adjacent the rear flue sheet 20. However, I do not limit myself in all cases to placing the bifurcation points near one or the other of the flue sheets.

As illustrated, the forward ends of flues 24a extend through the front flue sheet directly from the points 28 so that the front flue sheet 22 contains as many joints as though no bifurcated flues were employed. However, the use of bifurcations near the front flue sheet 22 is prohibited in the arrangement illustrated by the superheater units 26 and I do not limit myself in all cases to the use of such units or to the use of large flues. If the superheater units are omitted, all the fire tubes may be of the same size and they may all be bifurcated, or united in pairs, at both. ends within my invention.

As best appears in Figs. 1 and 2 the throats 24b are offset so that the axis of each throat 2422 comes more nearly in line with that of one of the flues 24a to which it connects than with the axis of the other such flue. Such an offset ar rangement permits me to place the throats 24b and the joints between such throats and the tube sheet 20 at a lower level than would other wise be possible for the upper row of flues.

See Fig. 2. I am able, therefore, to lower the crown sheet 14 because good design requires a certain distance between the upper row of joints in the sheet 20 and the crown sheet 14. The danger of damage to such sheet due to low water is thereby considerably reduced.

The pairs of tubes 24a and their connected throats 24b can be easily removed from the barrel 10 when so desired through the usual manholes 30, provided in the front flue sheet 22,

It will be seen that, when compared to a given design within the present state of the art, my invention permits a lowering of the height of crown without reducing evaporation appreciably or impairing the efficiency of the superheater.

This permits an increase in steam space and disengaging surface or a decrease in the weight of the boiler.

What I claim is:

A horizontal fire tube boiler having at least the top row of its tubes united in pairs to common throats and each of said throats connected into a tube sheet, the points of bifurcation at which the pairs of tubes connect to their throats lying nearer the tube sheet which is at the hotter ends of the tubes than to the other tube sheet and each throat common to a given pair having its axis off-set toward the axis of one tube of a pair and the axis of the throat lying nearer the axis of the lower tube of the pair than to the upper tube of such pair whereby the vertical height of the hotter tube sheet may be decreased for a given distance between the upper openings in such tube sheet and its top edge.

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