US2310496A - Stoker fired locomotive - Google Patents

Description

' Feb. 9, 1943.

c. J. SURDY STOKER FIRED LOCOMOTIVE Filed Jan. :50, 1940 3 Sheets-Sheet 1 INVENTOQX Char/e4 JJqfZ/y j ATTORNEYS "Feb. 9, 1943. c. JI SURDY I STOKER FIRED LQCOMOTIVE T --Filed Jan. so. 1940 5 Sheets-Sheet 2 INVENT OR BY Char/a Jfiurafy Patented Feb. 9, 1943 sToKEa FIRED LOCOMOTWE Charles J. Surdy, Erie,;Pa., assignor to The Standard :Stoker Company, Incorporated, a corpora tion of Delaware Application January 30, 194(l, Serial No. 316,396 3 Claims, (01. 110-87) 'This invention relates to coal burning steam locomotives of the type which employ a stoker for feeding and distributing the coal over the firebed.

In the conventional type of coal burning steamlocomotive, the firebox located at the rear of the boiler includes a combustion arch which extends from the front waterleg' toward the backhead of the locomotive. The arch is formed of refractory material, supported upon water circulating tubes, and extends from the front waterleg to a point short of the backhead to provide an opening extending across the rear of the firebox through which draft is induced in a-manner wellknown in the art. The bottom of the firebox is "formed by grates having air openings therethrough of predetermined size so that the required volume of air necessary to complete combustion may be entrained therethroughby the formation of a sub-atmospheric pressur'e'condi box of this construction by stoking means, it has been customary to dispose the discharge end of the stoker conduit at a point adjacent the backhead of the locomotive. With such positioning of the stoker it has been found in certain instances that the relatively small pieces of coal, when projected forwardly by the stoker distributor, are caught by the swiftly moving gas currents at the backhead of the locomotive and are carried out through the stack of the locomotive in'a' partly unconsumed form, due to the factthat the time provided for combustion has not been sufficient. l I

In order to eliminate this loss of fuel, it has been proposed to locate the stoker discharge conduit at a point adjacent the forward end of the firebox beneath the arch, at which point the velocity of the gas is considerably lower. While this arrangement results in' reduction of fuel losses, some difficulties in such arrangements have been encountered, among which are the space limitations beneaththe lower part of the arch, the increased length of the stoker conveyors, requiring greater number of parts, and

the fact that a higher initial velocity must be imparted to the coal by the stoker distributor in order that it may be traveling at a sufficient velocity toward the end of its travel so as to penetrate the zone of high gas velocity at the backhead of the locomotive.

In an effort to obviate the difficulties which have been encountered in the stokers of the type which feed at the forward part of the firebox, While at the same time attaining the desirable reduction of fuel losses, it is proposed by this invention to so construct the locomotive firebox that the primary opening for gases will be located adjacent the front waterleg of the locomotive firebox, whereby the stoker may feed at a point adjacent the backhead of the locomotive.

By this relation of parts, the zone of highest draft intensity will be transferred from the back of the firebox toward the front so that as the coal is projected forwardly by the distributor from a point adjacent the backhead, it will not be caught immediately by the high draft. At the same time, the stoker conveyor can be constructed with a minimum number of parts.

It is, therefore, the principal object of this invention to so reconstruct the conventional form of locomotive firebox that delivery of fuel by the stoker means can be made at a point adjacent the backhead of the firebox at which point the velocity of the draft is reduced substantially.

It is also an object of this invention to provide a locomotive firebox having an arch which extends downwardly from the backhead to a point short of the front waterleg, providing a primary opening for gases at such point, and the added provision of a secondary arch which extends a over such primary opening so as to prevent short circuiting of the flame travel.

. Another object of the invention is to provide in an arrangement such as that set forth, a rela- 40 firebox in the primary arch in order to attain tivelysmall opening at each back corner of the uniform heat transfer along the crown sheet of the locomotive firebox.

Astill further object of the invention is to provide a. primary arch which extends downwardly from the crown sheet of the locomotive firebox, at a point forward of the backhead, toward the front waterleg of the firebox to a point short thereof, providing a primary opening at such point; another object is the further provision of a secondary arch which is spaced over and above such primary opening.

These other objects, together with their attendant advantages will become apparent as the following descriptionsof the invention is read in connection with the accompanying drawings, in which Figure 1 is a longitudinal sectional view of a locomotive, with parts broken away, showing the improved firebox construction with the stoker in position;

Figure 2 is a transverse section taken along the line 22 of Figure 1;

Figure 3 is a section in plan taken along the line 3-3 of Figure 1;

Figure 4 is a view similar to a portion of Figure 1, showing a modification; and

Figure 5 is a transverse section taken along the line 5--5 of Figure 4.

Figure 6 is a section in plan taken along the line 66 Figure 4.

Referring first to Figures 1 to 3, inclusive, L indicates a locomotive comprising a frame It] which is carried upon the running gear II in known manner. Above the frame In is a boiler l 2 which includes a firebox I3 and flues [4 for conducting products of combustion from the firebox l3 to the smoke box I 5, the latter being disposed at the forward end of the locomotive boiler.

Drafting of the firebox I3 is accomplished by means of a nozzle l6 disposed within the smoke box l5 and through which nozzle l6 steam from the locomotive driving cylinders (not shown) is exhausted to atmosphere from the stack II. The swiftly moving exhaust steam within the smoke box 15 creates a subatmospheric condition within the firebox l3 and causes air to be admitted thereinto through suitable openings in and between the grates [8, which form the bottom of the firebox l3. The firebox I3 is defined by the grates l8, a back flue sheet IS, the backwall 26, side walls 2|, 22, the crown sheet 23 and the front waterleg 24; the said backwall, side walls, and the front waterleg constituting water circulating elements of the boiler. Extending upwardly and rearwardly from the front waterleg 24 are a plurality of transversely spaced Water circulating tubes 25 which open at their rearward ends into the hollow backwall 20.

In accordance with the present invention, the water circulating tubes 25 support a primary combustion arch 26, formed by refractory material. This primary arch, for the greater part, is sealed at the backhead 26 and extends downwardly along the water circulating tubes 25 to a point short of the front waterleg 24 to provide an opening 21 along the forward portion of the firebox. Since the arch 26 is preferably made of separable bricks, a bead 28 is provided on each water circulating tube 25 to form a stop for the lower end of the arch 26. At each back corner of the firebox the arch 26 is formed so as to leave an opening such as 29 for the purpose to be hereinafter described.

With the opening 2'! along the front water portion of the firebox and adjacent the rear flue sheet l9, it is obvious that the arch 26 would not function to provide for a long flame travel and to otherwise effect its normal function of securing improved combustion in the firebox, since the flame would be short-circuited and be drawn through the fiues without any appreciable baffling action. To obviate this, there is provided a secondary arch 30 which is spaced over the opening 21 and supported by means which may be in the form of a thermic-syphon 3 I the latter opening at its lower end along the front waterleg 24 and at its upper end opening into the boiler through a suitable aperture in the crown sheet 23.

In spacing the secondary arch over theopening 21, care must be exercised to insure that the openings between the primary arch 26 and the secondary arch 30, and between the secondary arch and the crown sheet 23 are at least equal to the total cross section area of the tubes I4 in order that drafting of the firebox 13 may not be impaired.

With a firebox constructed in the manner set forth above, the stoker S may feed into the firebox at a point adjacent the backwall 26 and thus be made as cheaply as possible. In the present embodiment, the stoker S may include a discharge conduit 40 which feeds into the firebox l3 through the handfiring opening 4| formed in the backwall 20 above the cab deck 42. The discharge conduit 40 is rigidly carried by the locomotive and at its lower end receives coal from a conveyor 43 which leads forwardly from the tender (not shown). There is a screw 44 in the conveyor 43 which urges the coal upwardly through the stoker discharge conduit 46. At the discharge mouth 45 of the conduit 40 there is a steam nozzle 46 which issues blasts of pressure fluid in a forward direction across the upper surface of a distributing table 41. The latter is provided with a pair of ribs 48 which may extend above the upper surface of the table 41. Goal delivered from the discharge conduit 4!) falls in front of the nozzle 46 and is propelled forwardly across the upper surface of the table 41; some of the fuel strikes the curved ribs 48 and rebounds toward lateral portions of the firebox.

With the firebox and primary and secondary arches constructed in the manner set forth above. it will be obvious that the heaviest draft will be immediately beneath the opening 21; the intensity of draft decreasing progressively toward the back of the firebox, at which point coal is delivered by the stoker S. Thus, the finer particles of coal which are struck by the blasts of the pressure fluid issuing from the steam nozzle 46 are not immediately caught by a heavy draft. Instead, the finer particles are projected forwardly and are given a relatively long travel due to the relation of the primary and secondary arches. This results in more complete combustion of the coal.

In order that the necessary transfer of heat may be'made to the rear portion of the crown sheet 23, the primary arch 26 is provided with a pair of apertures at each back corner of the firebox, as at 29, whereby some of the products of combustion may pass from the firebox l3 therethrough and along the underside of the crown sheet 23. In this way, hot gases may travel along substantially the full length of the crown sheet in order that evaporation of water in the boiler l2 may be facilitated.

In the modification illustrated in Figures 4 and 5, the primary arch 26a is supported by a plurality of water circulating tubes 25a which extend downwardly from the crown sheet 23 to the front waterleg 24. The upper lateral portions of the arch 260. may also be provided with opening such as 290. for the purpose of causing hot gases to pass along the underside of the crown sheet 23. In all other respects this form of the invention is similar to that illustrated in Figures 1 to 3, inclusive.

It will be observed from Figures 1 and 4 that a primary draft opening has been provided adjacent the front waterleg of the boiler. With the opening in this position, it will be of prime importance that a level and thin fire be carried in the firebox in order that the primary opening may be kept free for proper drafting of the fire. In this manner, a bright level fire will always be maintained with increased efilciency of the locomotive due to a more complete combustion which is possible with this type of fire. It will also be apparent to those skilled in the art that by the arrangement herein proposed, losses incidental to the escape of unburned particles of fuel through the stack I1 will be reduced materially, while at the same time a stoker can be utilized which consists of but few parts.

I claim:

1. A firebox having a grate, a top wall, up-

standing side and end walls with a firing opening in one of said end walls intermediate said side walls, a transversely disposed primary arch in said firebox extending the width thereof, said primary arch sloping downwardly from that end wall provided with the firing opening and from a position above said firing opening toward the opposite end wall, said primary arch terminating short of said opposite end wall to provide a primary opening for the passage of products of combustion, said primary arch at its upper end having a corner recess above and at each lateral side of said firing opening to provide a passage at each upper corner for products of combustion, a secondary arch sloping upwardly from said opposite end wall over and above said primary opening and terminating short of said top Wall to form an opening for the passage of products of combustion.

2. A firebox having a grate, a top wall, upstanding side and end walls with a firing opening in one of said end walls intermediate said side walls, a transversely disposed primary arch in said firebox extending the width thereof, said primary arch slopingdownwardly from a position on that end wall provided with the firing opening and from a position above the firing opening toward the opposite end wall, said primary arch terminating short of said opposite end Wall to provide a primary opening for the passage of products of combustion, said primary arch at its upper end having a corner recess above and at each lateral side of said firing opening to provide a passage at each upper corner for products of combustion, a secondary arch sloping upwardly from said opposite end wall over and above said primary opening and terminating short of said top wall to form an opening for the passage of products of combustion.

3. A firebox having a grate, a top wall, upstanding side and end walls with a firing opening in one of said end Walls intermediate said side walls, a transversely disposed primary arch in said firebox extending the width thereof, said primary arch sloping downwardly from a position on said top wall toward that end Wall opposite the end wall provided with the firing opening and terminating short thereof to provide a primary opening for the passage of prodnets of combustion, said primary arch at its upper end having a corner recess above and at each lateral side of said firing opening to provide a passage at each upper corner for products of combustion, a secondary arch sloping upwardly from said opposite end wall over and above said primary opening and terminating short of said top wall to form an opening for the passage of products of combustion.

CHARLES J. SURDY.

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