US1821134A - Superheater unit and boiler using same - Google Patents

Description

Sept. 1, 1931. J. A. BARNES I 1,821,134

SUPERHEATER UNIT AND BOILER USING SAME Filed May 31, 1930 IN V EN TOR.

John ABarnes.

ATTORNEY l atented Sept. 1 1931 TATES PATENT OFFICE JOHN A. BARNES, OF CHAIEPAQUA, NEW YCB/K, ASSIGNOR 'TO THE SUPERHEATER COMPANY, OF NEW YORK, N. Y.

SUPERHEATER UNIT AND BOILER USING SAME Application filed. May 31, 1930. Serial No. 457,998.

My invention relates to superheater units and more particularly to those employed in smoke tube boilers and to boilers employing such units.

Superheater units under certain conditions which occur in operation have a core of steam at lower temperature than the layer in contact with the inner surface of the unit. This condition is more apt to occur when the engine supplied by the boiler is operating under light load and results in supplying the engine with steam of lower temperature than that desired. The rapid changes of cylinder and piston temperature produced by variations of steam temperature cause undesirable stresses in the engine cylinder parts.

It is the principal object of my invention to provide a smoke flue superheater unit which shall maintain a more uniform steam temperature with varying loads than is obtained with superheater units of the type ordinarily used in smoke tube boilers.

The novel features of my invention are pointed out with particularity in the ap pended claims. In order, however, that my invention may be clearly understood, I will now describe in detail, in connection with the accompanying drawings, an illustrative embodiment of my invention. In the drawings,

Fig. 1 is a longitudinal sectional view taken on a vertical plane through the rear end of a locomotive boiler in accordance with my invention.

Fig. 2 is a fragmentary sectional view of a portion of Fig. 1 illustrating the return bend portion of a superheater unit in accordance with my invention on an enlarged scale.

Referring to the drawings more in detail, 10 indicates the shell of a locomotive boiler having a furnace chamber 12 and a tube sheet 14 at the front of the chamber 12. Large smoke tubes 16 and ordinary smoke tubes 18 have their rear ends opening into the fire box 12 through apertures in the flue sheet 14 and are connected to the flue sheet in the usual manner. The large tubes 16 are designed to receive superheater units 20, 20, such units extending rearwardly 1n. the usual manner to points somewhat close to the flue sheet 14 at which points the parallel pipe lengths 22, 22 of the units are 28, 28 of materially less diameter than the.

lengths '22 and whose open mouths lie centrally oflengths 22 in a plane transverse to the axis of pipe 22'adjacent the inner wall 30 of the return bend 24. The pipe lengths 28 extend in the general direction parallel to the lengths 22 and pass through apertures in the outer wall 32 of the bend 24, the outer ends of the lengths28 being connected by a second return bend 34. It will be seen, therefore,.that.as clearly indicated by the arrowsin Fig; 1, the central core of steam in pipes 22 is taken out at points near bends 24 by pipes 28 of extensions 27 in which the steam is further heated and returned to the large pipes of the units at points adjacent to, but on the other sides of inner walls 30 from which the steam was taken out. In order to assure tight joints at the points where pipes 28 pass through the walls of bends 24 I prefer to weld the pipe lengths 28 to the bends by oxyacetylene or electric welds indicated at 36, 36.

As above indicated, the smoke tubes 16 for receiving superheater units are reduced in diameter at their rear or intakeends forming shoulders 26. In order that the extension units 27 may act with maximum efficiency, I prefer to extend them into the reduced portions 38 of tubes 16 and for this purpose bend the pipe sections 28 as indicated at 39 so that the rear ends of such sections lie close together and may be readily inserted into the reduced tube ends 38.

In the case of a boiler designed initially to use units within my invention, the distance between the return bends 34 and the flue sheet 14 will be made such that the bends 34 will not be overheated. The temperature a given distance forward of the flue sheet 14 depends upon the construction of the fire box and the fuel used therein so that a locomotive boiler originally designed for the ordinary type of superheater unit sometimes cannot employ a unit in accordance with my invention on account of there being danger of over-heating the return bend 34. In such cases, however, I have found that it is usually possible to install an arch of spaced water tubes 40, or other heat absorbing surface, in the fire box 12 so that the gases must pass over it before reaching the flue sheet 14 and thereby to protect the return bend 34 from over-heating.

I claim:

1. A superheater unit having pipe lengths connected by a return bend and pipe lengths of smaller diameter than said first pipe lengths having mouths opening within said first lengths and extending in the same general direction as said first lengths throughthe wall of said bend at the outer side thereof, means forming a steam tight joint between said wall and said smaller pipe lengths, and a return bend connecting said smaller pipe lengths outside said bend.

2. A superheater unit as set forth in claim 1 and in which the pipe lengths of smaller diameter are set closer together for the portion of the lengths adjacent the bend connecting them.

3. The combination with a boiler having a smoke fine of reduced diameter near its inlet end, of a superheater unit in said fine and having pipe lengths connected to a return bend near the portion ofthe smoke flue of reduced diameter, said unit having relatively small and short pipe lengths extending through the outer wall of said return bend and opening into said first pipe lengths adjacent said bend, said smaller pipe lengths lying close together at their forward. ends and extending into the reduced portion of said smoke flue, and a return bend connecting said forward ends.

4. The combination in a heat absorbing element of a main unit comprising a pair of parallel pipe lengths connected at one end by a return bend, an auxiliary unit adapted to withdraw the central core of steam out of one of said lengths adjacent said bend and to return it to the other of said lengths adjacent said bend.

5. The combination in a heat absorbing smaller lengths.

JOHN A. BARNES.

element of a pair of parallel pipe lengths united at one end by a return bend and a pair of relatively small diameter pipe lengths in almement with said lengths passing through

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