US1930052A - Engine exhaust nozzle - Google Patents

Description

1933. J. R. JACKSON ENGINE EXHAUST NOZZLE Filed Jan. 6, 1930 2 Sheets-Sheet l INVENTOR JH/v JAcKsa/v BY F/a Z A'ITORNEYS Oct. 10, 1933. J. R. JACKSON 1,930,052

ENGINE EXHAUST NOZ ZLE Filed Jan. 6, 1930 2 Sheets-Sheet 2 INVENTOR JOHN R JACKSON BY CQQ JM ATTORN EYS Patented Get. 10, 1933 UNITED STATES PATENT o l-"Flor.

7 Claims.

The object of the invention,. generally stated, is the provision of improved. apparatus for automatically controlling or governing the.- back pres.- sure inthe. exhaust lines of. a steam locomotive, which apparatus may, and bypreference does, serve" materially to affect the draft of. a. steam locomotive with which ity is employed.

A further object of. the invention is to provide a nozzle stand for steam locomotives: in which provision. is made for a delivery orifice or exhaust nozzle tip of improved. construction, the means: forming; such orifice constituting a separate exhaust delivery opening of variable area, for the exhaust stream from each cylinder.

A. still further object is to provide an exhaust orifice or nozzle of sucha, construction as to provide for the variable pressure.- and volume of the several strearnsof exhaust fluid, providing a maximum area of exhaust opening at times when the volume of. each individual stream of exhaust fluid is at. a maximum, such as during lower speed, long cut-off operation, and providing a minimum area at times when such stream is of lesser volume, such as. occurs, at high locomotive speeds when the engine is operating. at, a shorter cut-off.

A. still further object of the invention is the construction of an: improved exhaust nozzle, such that the relatively high energy in the exhaust stream from one cylinder, existing at the moment of its: release, serves to entrain andinduce the exhaust steam from the. exhausting end of another cylinder of the locomotive. The attainment of this object minimizes the back'pressure acting: against. the pistons, with a resulting conservation of power and increase in efliciency.

A still further object of the invention is to provide. a device attaining the objects heretofore stated, and which is entirely automaticin its. operation, requiring no manual actuation, and characterized by an. absence of operating orcontrol mechanism: disposed external tothe: exhaust nozzle stand.

Further objects and advantages of the invention will appear from the drawings, together with the: accompanying detailed descriptionthereof,

Referring to the drawings, Fig.1 is a plan view, partly in section, of a preferred embodiment. of the present invention, Fig. 2 is a lateral, sectional elevation of. the device appearing in, Fig. 1, and .Fig. 3 is a vertical sectional elevation through they smoke box of a locomotive. of the usual type to which. the invention has been applied, and illustrating a preferred relation to the. stack and parts associated therewith. v I

Referring now by characters of reference to the drawings., the exhaust stand assembly, indicated generally at 10 is, by preference, disposed in the lower, central portion of the smoke box, (Fig. 3) By further preference, the exhaust nozzle or stand is arranged coaxially of. the stack 12 which has its upper or outer end in free communication with the atmosphere. It will. be understood that the smoke box is in free communication, with the atmosphere only through the stack opening; that the. outer end wall of the smoke box constitutes the front closure of the locomotivev structure, and that the inner, end wall or header 13 constitutes a closure. for the opposite end of the smoke box. As is well understood in the art, the lines terminate in header l3- and thereby provide smoke passages from. the fire box, which passagesv terminate in the smoke box 11, whence theproducts of combustion escape through the stack 12, all as known in the art.

As will be understood, the streams of exhaust steam issuing from the severalcylinders, of the locomotive are all conducted through the several exhaust pipes. (not shown) into the bottom portion of the exhaust nozzle or stand structure, best seen in Fig. 2, and the several exhaust streams conducted through the upper or outer end of the stand for escape through the stack. The movement of such exhaust streams asthey proceed outwardly through the stack, results in an ejector action. by virtue of which certain particles of the air and products of combustion occupying the smoke box 11, are induced or entrained with the exhaust steam. issuing from the nozzle 10, and expanding through the stackwith the result that the draft through. the flue passagesfinot shown) and hence through the fire box and fuel bed (not shown)- is materially increased.

The. present invention as applied to a steam locomotive, results in a marked increase in the entrainment and induction of smoke box fluid and solids so. as. greatly to. enhance the draft of the engine over its range of normal operation. Of equal or perhaps greater importance is the effect in using the invention to be described, of

each exhaust fluid stream in aiding the expulsion versely of the stand 15 and disposed intermediate 1y of its sides is a stationary dividing wall 16 serving as a separator between the exhaust passages from cylinders on opposite sides of the engine. A flange 1'7 may be provided for effecting a coupling to the exhaust pipes or passages leading to this point. Carried by the wall 16 and preferably journaled at the outer extremity thereof, is a pivot member 18 to which, in turn, is journaled a movable partition 19, which may consist of a single element as shown, or any selected number of separatemembers, arranged to oscillate or vibrate freely between limits established by the opposite Walls of the structure 15, as will clearly appear from Fig. 2. The pivot or shaft 18 may be held against longitudinal displacement by any suitable means, such as threaded plugs or thecaps appearing in Fig. 1. The movable partition is constituted, by preference, of a one-piece structure formed as by casting of a suitable metal to resist the heating effects of steam and flue gases, and to withstand repeated vibrations. By preference, the material constituting the partition is so selected as ,to give this member a lowmoment of inertia.

By great preference the pivoted dividing wall 19 is formed of tapered width, having its maximum cross dimension near its outer end. This member is, by further preference, of fluted construction, being laterally indented or recessed, as appears in Fig. l. Recesses and projections of corresponding width are alternately disposed on each side of the member, and with the projections and recesses on each side disposed in staggered or off-set relation to those on the opposite side of the structure, as will clearly appear in Fig. 1. In the present example there is thus provided a series of alternate projections and recesses of a vertical trend, extending longitudinally of the partition, and forming furrows on each side thereof.

As will hereinafter more clearly appear in the discussion of operation of the device, the exhaust streams alternately projected into the nozzle, at opposite sides of the movable partition, tend to swing or oscillate this member from side to side. Unless means are provided to dampen or check such movement, the partition may be brought into impacting relation with opposite sides of the structure 15. To the end of avoiding this impact, and of damping, to a certain extent, the vibrations of the pivoted dividing wall, it is my preference to provide some suitable checking means, such as a dash-pot structure on each side of the stand, consisting in the present instance, of a piston 20, which may be provided with any suitable packing (not shown), the piston operating in a cylinder 21, which may be cast as part of the structure 15, or formed separately therefrom as desired. Each piston 20 is operatively associated with the movable partition 19 through links 22, pivoted as at 23 and 24. By preference, the pistons are not closely fitted within the cylinders, but sufiicient clearance is allowed so as not to impede too greatly, the movement of the partition. If desired, a valve (not shown) or other suitable means, may provide a restricted opening from cylinders 21 to the atmosphere. By preference, the upper or outermost portion of the structure 15 forms a passage which is relatively constricted as at the point 25 .near the delivery end of the structure and beyond the outermost portion of the partition 19. This restricted throat serves materially to increase the velocity of the exhaust fluid just before it leaves thenozzle or stand, this increase in velocity serving to enhance the induction and entrainment action of the exhaust streams to, attain a desirable scavenging or ejector action of one exhaust stream, by which it aids the delivery or expulsion of the succeeding stream, and further to increase the draft resulting from effective entrainment and induction, by the flow of exhaust steam, of solid and gas particles in the smoke box.

The advantages in use and the manner of operation of my device, are thought to be fully apparent from the preceding description of its parts, but may be briefly set forth for sake of completeness of description as follows, the device being first considered under conditions of slow speed, long cut-off locomotive operation. The exhaust steam liberated from either end of a cylinder, by the movement of the main locomotive valve, passes into a connecting exhaust passage (not shown) and builds up pressure within the nozzle stand housing 15 on one side of the central pivoted dividing wall member 19. Since there exists a relatively low pressure on the op- -posite side of this wall at this time, the partition will swing from the high pressure side to the low pressure side, thus by reason of the shape and proportion of the parts quickly creating a larger area for liberation of steam on the release side at the relatively'higher pressure, and at the same time utilizing the energy contained in the outflowing stream, for the purpose of inducing a scavenging flow of the much lower pressure exhaust steam on the opposite side of partition 19. As the exhaust flow through the stand is alternated, the operation above described repeats itself on the opposite side of the stand. The device, as will appear, is of a balanced design such as to care for the exhaust streams issuing from the two or more separate cylinders on the locomotive in the order of release of the exhaust steam therefrom. Since the cylinders exhaust alternately, and the streams alternately projected through passages at opposite sides of the partition-19, the action of the partition consists of a mechanical swinging movement or vibration through its max imum arc of movement as it yields alternately in opposite directions under the influence of the oppositely acting exhaust pressure peaks. Since at low-speed long cut-off locomotive operation, a substantial time interval prevails between succeeding exhaust releases, the time interval of oscillation of the partition 19 permits this member to swing through its full range, and thus to provide the desirable maximum nozzle area to prevent building up excessive back pressure at the time of each exhaust release. The mechanical movement of the partition is, however, sufficient to prevent any gumming, corrosion, or carbon formation to interfere with its-free movement about the shaft 18. 1

As the speed of the locomotive increases, the time interval between exhaust releases is correspondingly decreased and as an incident to this operation, the steam cut-off is shortened by the engineer. As-the interval between exhaust releases is decreased, the are through which it is possible for the partition 19 to swing, is also actually decreased. However, as the cut-off is shortened, the intensity of the exhaust release is likewise diminished. Due to these two influences, it is desirable to decrease the area of outlet opening existing at each'side of the exhaust nozzle. As the speed of thelocomotive increases, the exhaust nozzle orifice area devoted to each stream, becomes less until the locomotiveattains such speed that the opposing exhaust releases flow in such rapid succession as effectively to balance the pressure on the opposite faces of the pivoted dividing wall. This member then remains stationary, with the result that the structure constitutes two equal and separate nozzle jets, one for each cylinder. The proportion of the fixed and moving parts of the nozzle is such that when the partition attains this substantial equilibrium in mid-position, the nozzle orifices are sufiicient to relieve the engine of excessive back pressure, but at the same time the device coacting with the locomotive stack which is of constant sectional area, still serves to maintain the necessary ejector action properly to draft the locomotive.

It will appear from the preceding description of the parts of the device and their operation that the invention may be embodied in a structure not appreciably greater in space requirement, nor very much more expensive in construction than prevailing types of exhaust nozzle stands. It will further appear as an advantage that the device is fully automatic in its operation, requiring no exterior manipulating device or manual control and that its operation is thereby freed of the personal element. That the construction described is not only fully automatic, but requires a minimum of maintenance is evidenced by the fact that the vibrations or oscillations of the movable partition 19 prevent any tendency to sticking or clogging of the moving parts. In use, the present invention results in a marked reduction in back pressure at the time in the stroke cycle of each cylinder, where back pressure reduction is most effective in increasing the efficiency of the locomotive.

For convenience of description, and in compliance with the statutes, I have described the invention by making specific reference to a particular structure intended for application to usual types of steam locomotives. Obviously, certain features of construction and the principles embodied therein may be otherwise applied for the entrainment and induction of exhaust or other fluid. It will appear at once to those skilled in the art that a number of structural changes may be made, and the device employed, with or without changes, in stationary and locomotive engines of a variety of types, without departing from the spirit and full intended scope of the invention, as defined by the appended claims.

I claim as my invention:

1. In an exhaust nozzle for multi-cylinder steam engines, a pair of steam channels through the nozzle, and a tapered partition between said channels, and having a furrowed surface, disposed along the path of steam travel through said channels, and tending to cause a' divided, entraining flow of steam from each channel.

2. In an exhaust nozzle for a multi-cylinder steam engine, a longitudinally fluted partition disposed in the path of steam through said nozzle, and. adapted to augment the surface of the exhaust stream through the nozzle whereby to increase the entraining effect of such stream.

3. In an exhaust nozzle for a multi-cylinder steam engine, a nozzle body of unitary construction having a passage therethrough, a member dividing said passage and disposed for swinging movement crosswise of the nozzle passage, and adapted by such movement to vary, to an equal extent, the areas of nozzle discharge openings on each side of the member, and means for yieldingly opposing the movements of said swingable member.

4. In an exhaust nozzle for a multi-cylinder steam engine, a partition disposed centrally within and arranged for vibrating movement transversely of the nozzle, means carried by opposite sides of the partition, for dividing the exhaust streams through the nozzle, and adapted to cause an entraining effect of such streams, andfiuid means tending to check the movement of said vibrating means.

5. An exhaust nozzle-for multi-cylinder steam engines, including a chambered body member of polygonal section, and a partition of fluted construction disposed within and extending across said body member, and serving to divide the chambered portion of said member into a plurality of steam passages.

6. An exhaust nozzle for a multi-cylinder steam engine, including a body member having inlet openings at one end and an outlet or exhaust opening at the opposite end, a partition separating said inlet openings, a pivot carried by said partition, a movable wall member constituting a continuation of said partition and having projections and depressions on its opposite sides, said projections and depressions extending 1ongitudinally of the passage through said nozzle, said movable wall member arranged for swinging movement transversely of the nozzle under the influence of alternate exhaust impulses, said body member having a portion of restricted sectional area adjacent the outer extremity of said movable wall portion; and a checking device disposed on each side of, and in pivoted relation to said movable wall member.

'7. An exhaust nozzle for multi-cylinder steam engines including a nozzle body of fixed dimensions, a pivoted partition member disposed so

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