US1942676A

US1942676A - Superheater

Info

Publication number: US1942676A
Application number: US627909A
Authority: US
Inventors: Williams Arthur
Original assignee: Superheater Co Ltd
Current assignee: Superheater Co Ltd; Superheater Co
Priority date: 1932-08-08
Filing date: 1932-08-08
Publication date: 1934-01-09
Anticipated expiration: 1951-01-09

Description

Jan. 9, 1934. A, w u s 1,942,676

SUPERHEATER Filed Aug. 8, 1932 s Sheets-Sheet 1 INVENTOR ATTORNEY Jan. 9, 1934. w u s 1,942,676

SUPERHEATER Filed Aug. 8, 1932 3 Sheets$heet 2 INVENTOR ATTORNEY A. WILLIAMS Jan. 9, 1934.

SUPERHEATER Filed Aug. 8, 1932 3 Sheets-Sheet 3 INVENTOR.

A TTORNEYS.

Patented Earn. 9, 19 3 1 UNHTE #55.

PATENT OFFICE SUPERHEATER Application August 8, 1932. Serial No. 627,909

6 Claims.

The invention relates to superheaters of the socalled flue type which is in common use in locomotives, and has for its purpose the provision of a device of this kind which will furnish a higher 5 degree of superheat than can be obtained by superheaters of this type as usually constructed. The invention is illustrated in the drawings filed herewith in which Fig. 1 is a vertical longitudinal fragmentary section of a locomotive with a superheater in accordance with the invention. Fig. 2 is a section on line 2--2 of Fig. 1. Figs. 3 to 8 are sections similar to Fig. 2 showing variations. Fig. 9 is a longitudinal section of a flue and a different form of superheater element utilizing my inven- 15' tion. Fig. 10 is a section on line 10-10 of Fig. 9. Fig. 11 is a longitudinal section of a flue with another form of superheater element according to my invention. Fig. 12 is a section on line 12--12 of Fig. 11. Figs. 13 and 15 are diagrammatic representations of further superheater elements to which my invention is to be applied, Figs. 14. and 16 being respectively sections on lines 1414 and 16-46 of Figs. 13 and 15.

Referring first to Figs. 1 and 2, there is shown in the former of these two figures enough of the locomotive to indicate the location of the superheater element, one of such superheater elements being shown in the figure. 1 is the barrel of the boiler, 2 being the front flue sheet and 3 the rear flue sheet. These two flue sheets are connected by the flues 4-"=. Gases from the fire-box 5 flow through the flues 4 to the smoke box 6. In the upper part of the smoke box is located in accordance with usual practice the superheater header 5 7, which may also be of ordinary construction, and to which steam is delivered by the dry pipe 8. The superheater header has in accordance with ordinary practice a series of fingers or subsidiary headers 11, alternate ones of which are connected to the transverse chamber 12,.the intervening ones communicating with the chamber 13. The tubular superheater elements 14-14 have in accordance with the usual practice two ends each, one of them connecting with a chamher 11 in communication with chamber 13 and the other end with a chamber 11 communicating with chamber 12. This detail does not show in the figure but is well understood by those familiar with this art. After having been superheated in the elements 14 and delivered back to the header 'I, the steam flows to the steam chests through the steam pipes 9 (only one of which shows in the drawings). The flow of the steam from the header 7 to the steam pipes 9 is controlled by the 55, multiple throttle 10. The exact form of the header is immaterial as will be seen from the ensuing description.

The invention described and claimed herein resides in the form of the tubular elements 14. Each of these elements is made up of five pipes. Four of these, 14a-14a (see Fig. 2), carry the steam in a direction from the smoke box 6 toward. the fire box 5 and the other one, 14-b, carries the steam from the fire box end of the element toward the smoke box. The first four lengths lea-14a are connected to a forging or casting 15 which receives steam from one of the subheaders 11 in communication with the chamber 13.

In superheater elements as heretofore constructed, the gases which deliver their heat to 7 the tubular element and thereby superheat the steam flowing through the element, are also exposed to the walls of the flues in which the superheater elements are located. These flues being cooled by the boiler water on their outsides and therefore being considerably cooler than the superheater surfaces, cause the temperature of the gases to fall much more rapidly, as the gases flow toward the smoke box, than they would be cooled if they were exposed only to steam-cooled surfaces. As a result, the degree of superheat which can be obtained in such an element, located and constructed as heretofore, is strictly limited.

It is the purpose of the present invention to modify this structure in order to make it possible to obtain higher degrees of superheat. Briefly stated, this is done by confining a portion of the gas current flowing throughthe flue so that such portion is not exposed to the cooling influence of the Water cooled flue wall. This can be accomplished in a number of different ways. The section shown in Fig. 2 shows the fins 1616 .which are welded, two to each tube, and which are so arranged that they, together with the tubes 14a, enclose, or substantially enclose, a portion in the center of the flue. The return pipe l lb'lies within this enclosed portion. These fins 16-16 extend from a part of the element adjacent to its fire box end forward substantially to the smoke box. At the flre box the spaces between the tubes are left open for a sufficient distance so that gases can pass into the central enclosed part. In practice the fins are preferably each made up of a series of separate lengths, abutting end to end, although they may, if desired, be made integral throughout their length.

The result of this construction is that those gases which enter the enclosed central portion of the superheater element give up heat only to the superheater element and are not cooled by the water cooled surface. The gases flowing through this central part therefore constitute a hot core which is able to impart a higher degree of superheat to the steam than is possible with units used heretofore. Experimental units or elements embodying the invention have shown that the degree of superheat can be raised by as much as 50 degrees over what was possible with prior art elements.

It will of course be understood that there are as many horizontal rows and vertical rows of these elements as are required. In the instance of the superheater of Fig. 1, there are shown in addition to the one complete element, the ends of four more elements so that there are five elements in each vertical row. The number of vertical rows depends upon the size of the locomotive, the amount of steam generated, etc. As -a matter of practical importance, the newly proposed superheater elements are freely interchangeable with those used heretofore so that they can be employed as replacement units for existing installations as well as for wholly new installations.

V The forms of the element in Figs. 3 to 8 are generally like that shown in Figs. 1 and 2 except for the means used to define the central enclosed portion of the gas path. In Fig. 3, for example, the fins hid-16a are slightly curved so that in assembled relation they lie in a circle about the center of the flue. In Fig. 4 the fins are replaced by curved sheets 16?) secured to the sides of the tubes 14a away from the center of the flue. In

this construction each of the superheater tubes lie entirely within the enclosed portion instead of only in part as Figs. 2 and 3. This form of unit will yield exceptionally high superheat.

InFig. 5 the curved sheets 160 are secured to the sides of the tubes 14a lying toward the center of the flue and heat from the curved sheets 160 is conveyed to the steam in the tubes 14a only by conduction. The return tube 14th is however still entirely enclosed within the portion defined by the sheets 16c and therefore is exposed to very high gas temperatures.

The fins of one tube need not be separate from those of. another tube but may be unitary with them. Such constructions are shown in Figs. 6 and 7 which will be clear from a mere inspection of these figures. This feature may also be used in connection with the forms of the invention shown in Figs. 2 to 5.

.A variation allowing ashes and cinders carried by the gases to escape readily from the central enclosed part of the flue to the bottom, thence to be blown or washed out, is illustrated in Fig. 8, where the two lowerfins on the bottom two tubes 14aare for this purpose omitted.

It will be clear that while I have described the invention in connection with a five-pipe element in which the four outer pipes carry steam inward and .a single central one carries it outward or forward, the invention also has application to other forms of tubular units. In Figs. 9 and 10, for example, is shown a unit whose general construction follows the usual practice. One branch 17 carries steam inward toward the smoke box; a branch 18 (connected to branch 17 by the return bend 20) carries it forward; a branch 19 (connected to 18 by the return bend 21) carries steam inward again and a branch 23 (connected to 19 by the return bend 22) carries it forward again. There are, in other words, two complete loops extending into the flue, these loops being made up of four pipes connected in series. The cross section illustrated in Fig. 10 shows more clearly how the invention is applied to such a unit. The four

pipes

17, 18, 19 and 23 each have two fins 16-16 afiixed to them in such positions that they, together with the four tubes, enclose a central space in which the gases will not be exposed to the water cooled flue 4. The variations of Figs. 3 to 8 may also be used with this unit.

The invention can also be applied to the case of a unit or element made up of only two pipes constituting a single loop arranged in a flue. This is illustrated in Figs. 11 and 12. In the flue 4 there lies a single loop made up of the two branches 25-25. These have secured to them the fins 26-26 preferably curved and enclosing a central gas path.

A unit like that illustrated diagrammatically in Fig. 13 is also capable of having my invention applied. In this case the element has two branches 27-27 carrying steam inward or toward the left, a single 'branch28 carrying it .out. These branches are preferably arranged as illustrated in transverse section in Fig. 14, the two branches 27-27 lying in a horizontal "plane above the branch 28. The fins 16-16, two of which are affixed to each tube again enclose a central hotter gas stream.

In Figs. 15 and 16 there are three branches carrying steam in, these being designated by the reference numerals 27-27 and one branch 28 carrying the steam out. A variation is shown here as far as the fins are concerned, namely, that the space between adjacent tubes may be closed by a single fin attached to one tube instead of by two fins extending from the two tubes. The top of the three tubes 27 has fins 1611 extending to the other two tubes 27 so that these second tubes 27 are not themselves provided with fins at these points. This variation can evidently be used .in others of the forms shown.

It will be clear that the gases in the central enclosed portion, while remaining hotter and therefore being capable of imparting a greater degree of superheat to the gases, will also be delivered to the smoke box somewhat hotter than with units as constructed and used heretofore. The gases on the outside .of the enclosed space on the other hand will be cooled more rapidly than heretofore. This in turn will affect the evaporation. The loss in evaporation however is offset by the higher degree of superheat delivered by the 'superheater. In other words, the two work harmoniously together, the higher degree of ,superheat making it possible to work more economically and therefore use less steam, and the boiler at the same time delivering less steam for the reason mentioned.

It is obvious that other variations besides the ones pointed out above may occur in practice without departing from the real essence of the invention. 1

What I claim is:

1. In a device of the class described, the com bination of .a flue, four parallel pipes within the flue arranged in .a circle about the longitudinal axis of the fine, and two longitudinalfins on each pipe, the outer edges of the fins of one pipe being substantially in contact with those of the two adjacent tubes, whereby a central space is se apart .from the remainder of the flue.

2. Apparatus in accordance with claim .1, the four pipes being connected into a single tubular unit.

3. Apparatus in accordance with claim 1, and further comprising a fifth tube located in said central space, the five tubes being connected to each other at one end.

4. In apparatus of the class described, the combination of a flue, a plurality of parallel pipes within the flue arranged in a circle about the longitudinal axis of the flue, fins secured to the pipes and together with the pipes enclosing a central space, a further pipe extending longitudinally within said space, the pipes all being in communication at one end, the pipes arranged in a circle being connected to a source of steam supply, and the pipe within the space being connected to a steam consuming means.

5. In apparatus of the class described, the combination of a flue, a plurality of parallel pipes within the flue arranged in a circle about the longitudinal axis of the flue, and. metallic strips secured to the pipes to enclose a central longitudinally extending space in the flue through which gases may flow.

6. In apparatus of the class described, the combination of a 11118, a plurality of parallel pipes within the flue arranged in a circle about the longitudinal axis of the flue, longitudinal flns secured to the pipes and together with them enclosing a central space in the flue through which gases may flow.

ARTHUR WILLIAMS.