USRE13191E - stdmpf - Google Patents

Description

J. STUMPF. STEAM ENGINE. APPLIUATIOI` FILED AUG. 25, 1909.

Reissued Jan 3,1911.l 13,1191.

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STEAM ENGINE.

APPLICATION FILED AUG. 2s, 1909e Bissued Jan. 3, 1911.

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13,191. Original No. 908,624, dated January 5,

To all whom it may concern:

Be it known that I, JOHANN STUMPF, a citizen of the Empire of Germany, residing at Berlin, have invented-certain new and vuseful Improvements in Steam-Engines, moreparticularly to the Locomotive Type, of which the following is a full, clear, and exact description.

This invention relates to steam engines more particularly to locomotive steam e/ni gines of the type wherein the exhaust steam escapes through ports in the wall of the cylinder which-are controlled or uncovered by the piston.

The object of the invention is to overcome tributionwhich results from utilizing the same ports alternately for admitting steam to the cylinder and exhausting it therefrom.

types of valves and valve gear the passage ofthe exhaust' steam through the same ports through which it was admitted to the cylinder results in great variation in the lead and compression. This causes large losses in etl'iciency owing mainly to insuiicient compression when there is -a late cut- 'olf and the cylinder is filled ,with steam and nthecase of an early' cut off owing to excessive compression due to early closing of the exhaust. These losses are avoided by the exhaust being controlled lexclusively by the movement of the piston.

In a double acting steam engine vhaving exhaust ports situated abbut the center of the cylinder and lvcontrolled by the piston if the clearance be given normal dimensions the compression with a late cut off andhigh speed under certain circumstances maybefcome so great as to burst the cylinder or blow off its-cover. It is therefore necessary either to arrange suitably controlled auxiliary exhaust ports at the `ends of' the cylinder or to provide the inlet ports at the endsof the cylinder with non-return valves so that in the event of excessive compression occurring a portion of the compressed steam may be able to -return to the boiler.. 'Theirst "of these arrangements would neutralize compression which is sought to be obtained in providing a double acting steam engine with exhaust ports controlled by the .piston- The provision of inlet ports whichare on the disadvantageous effect on the steam dis- In existing steam engines with known thechief advantage as' regards lead and UNITED sTATEs PATENT OFFICE.

. STEAM-ENGINE.

Specification of vIELeissu'e Letters Patent. Reissued Jan. 3, 1911,

1909, Serial No. 427,78. Application for reissue' filed 'August 25, P1909. Serial N0. 5414,56032.

occasion also used as exhaust ports is on the other hand combined with serious draw backs more particularly -in locomotive engines. In consequence ofV a portion of the compressed steam being returned to `the boiler heavy thermodynamic losses are brought about while moreover there is the possibility of smoke being drawn into the cylinder with the resultant risk of burning the lubricating oil,` depositing soot in the cylinder andA fracturin it. This danger from smoke is more particularly tov be feared when the' throttle is closed and the pressure in the steam supply pipe reduced.

According to this invention vthe above mentioned drawbacks are obviated more especially in double acting locomotive engines by the inletports being used exclusively for the admission of V steam and by theirbeing positively controlled or operated by means of suitable valve gear of link or other type lcapable of reversing Further the cylinder and piston are suitably shaped to provide a clearance which will accommodate the steam remaining in the, cylinder after the exhaust ports are closed so that it isV unnecessary to arrange for the steam admission ports to be capable of occasional use as exhaust ports.

An engine with valves and gear con-l structed 1n accordance with this inventlon is illustrated in the accompanying drawings by way of example as applied to a locomotive.

Figure 1 is a somewhat diagranimatic view of the front portion of a locomotive showing a cylinder in longitudinal' vertical section. Fig. 2 is a broken cross section through one Side of the locomotive the sectionbeing taken midway in the length of the cylinder. Fig. 3 is a'plan of Fig. 2 partly, in section'with the boiler removed. Fig. 4 is an indicator diagram illustrative of the operation of the improved" engine.

Below the smoke box 1 on the frame 2 is mounted the cylinder 3 provided with covers`4. The cylinder 3 has exhaust ports and 6 formed about itsvcenter these ports beingv intendedexclusively for the steam exhausted from the cylinder and being controlled,by the piston l7 which covers and un` covers/them in its reciprocations. The pistonI 7 has :concave ends, which withthe sub-i stantially tlat or less convexed inner face ofA u the-(cylinder cover ,provide a suliicient clearance space at the end ofthe piston stroke,

y without necessitating increase of the length of the cylinder for this purpose. lVit-hin, the cylinder covers 4 are arranged valves S controlling the passages 'communicating with the cylinder by ports 9 these ports, passages and valves being exclusivelyjemployed for the admission of live steam. The

valves 8 are operated by rollers 15 on a common rod or spindle, the valve spindles l() being operated by cams 11 by means `of sleeves or guideblocks 12 whichv are disposed in cylindrical caps or casings 13 mounted on the cylinder covers 4, the valves being controlled by adjustable springs .14. The cams 11 coperate with rollers 15 carried on slides 16 connected by a spindle 17.l the slides reciprocatingin the caps 13. The

reciprocation of the valve spindle 17 with the guide blocks 16 necessaryto effect the o eration of the inlet apparatus 8 mayv be e ected by means of any known valve gea-r with eccentrics and link motion or other ar-A rangement adapted to enable reversal to be effected. The link motion illustrated is of the Walschaert type and being known need not be here further described. The slide blocks 16 are secured to a rod 18 lwhich is plvotally connected to the upper end cfa two armed lever 19 the lower end of which 1s pivota/lly connected by a link 20 to thc cross head 22 of the piston rod 21. At thcupper end there is pivoted to the lever'19 a rod 23 which carries a slide block 24 ad: justable in a radius link 25. The link 25 is centrally pivoted on a bracket 26 mounted onl the frame 2 of the locomotive and is v caused to oscillate in the well known manner by means of an eccentric rod 27 connected to its lower end. The end of the rod 23 which extends beyond the radius link 25 is connected by a link 29 with a bell crank lever 30, 31 moving on a fulcrum 28, a rod from the arm 31 of this lever extending to the cab and enabling the driver to alter the gear so as to vary the cut olf and reverse thev engine. Live steam is.. supplied to the Valves8 vfrom the boiler 33 through pipes 3 5 branching from a T-piece 34, the steam being delivered to the valves', in this way so as to heat the cylinder covers 4.

Inaccordance with a further feature of i this inventio-n the cylinder 3 .is constructed as hereinafter described so that hammering f valves 8 being two groups disposed respectively on the upper and lower sides (if the cylinder 3. The ports of the upper group open iifto a chamber 38 mountedy on the cylinder 3 and communicating with the main exhaust pipe which leads to the blast pipe 37. The ports 6 of the lower group communicate with a second outletconveniently constituted by'a chamber 39 on the underside of the cylinder3, the bottom of this chamber being provided with a comparatively small opening 40 communicating with the atmosphere. The dimensions of the lower exhaust ports 6 are so calculated that it is not possible for the whole of the exhaust steam to escape through them so that the necessary blast from the pipe 37 is always insured.

lVhen the exhaust ports 5 and 6 are uncovered by the piston the greater portion of the exhaust steam will pass through the ports 5 and th'e pipe 36 to the blast pipe 37 a smaller portion of the exhauststeam passing through the ports 6 into tne chamber 39 and carrying with it any waterv of condensa-` tion which is free to escape through'the outlet 40. The chamber- 39 constitutes at the same time a'water pocket and is for that reason made fairly large so as to enable it temporarilyzto take up large quantities of water of condensation such as are liable to be Jformed when the engine is being started. In addition to the outlet 40there are of course provided for draining the cylinder3` and the covers 4 the usual'cylinder cocks 41 which can be opened by the driver from the cab when requlred by means, of rods 43, 44 these cocks being operated simultaneously with a cock 42 which is provided for draining the steam chambers formed in the cylinder covers 4. When vrunning down hill the valves 8 are held open by means of mechanism described in my co-pending application, Ser. N o. 544,733. This mechanism is indicated by the rotatable members 45 which are articulated together by a link 46 and are operable from the engine cab by means of the rod 47.

The operation of the improved construction is as follows When the lever 10 is operated by the action of t-he cross head 22 and radius link 25 so as to Lmove the valve spindle 1,7 in a forward 'direction from the position shown in Fig. 1 the valve 8 at the front end of the cylinderwvill be opened by the corresponding roller l5 meeting and lifting the cam 11, t-he valve 8 at the other end of the cylinder however remaining closed under the action of its spring `l4. On the izo return movement of the spindle 17 the valve y V8 at the forward end of the cylinder is closed while the valve at the rear end= of the cylinder is opened by thercoresponding roller 15 raising its cam 11. On one of the opened live steam enters the cylinder'through the port 9, the 'piston 7 at the end of its travel in either direction V owing to its concave ends leaving between 1t and the covers 4 a clearance.- indicated at in the indicator diagram shown in Fig. 4. The dimensions of this clearance are calculated so as to insure that even in the case of late cut olfthat steam which fails to escape rthrough the exhaust ports 5 and' can not be compressed to an injurious extent on the return stroke of the piston. t

Referring to the indicator `diagram shown the cut off takes place at a followed by expansionup to the point when the exhaust tports 5 and are simultaneously uncovered by the piston 7 Whereuponthe greater portion of the exhaust steam escapes through the pipe 3G to the blast pipe 37 while a lesser `portion finds its rwayinto the chamber 39 Y and-so to the atmosphere through the outlet 40 carrying with it at the Sametime into the chamber 39 any water of condensation which may' have been present in the cylinder. On the return stroke of the piston '7 the exhaust ports 5 and 6 are again cov-ered at the point c so that the outlet 40 vand the exhaust pipe 36 are only in communication with the interior of the cylinder while exhaust is taking iplace. The, piston is given the dimensions necessary to prevent the parts 5 and 6 being uncovered except at the desired time.

. If by varying the position of the-radiusVV rod 23 in the link 25 by meansof the rod 32 and lever 30, 31 the cut off is altered or the engine reversed thenowing to the exhaust ports being controlled by the piston 7 the lead land compression will still remain constant. In this'way all the ,drawback `in working due to the variation in` the compression and lead are obviated. Owing to the compression being maintained constant the forces resulting from the moving masses of the parts of the engine 'are always properly taken up so that knocking of the mechanismA is e'ectively avoided whether in going up hill with a late cut olf or when going at high-,speed when the cut 0H must also be fairly late to overcome air resistance.

The arrangement of double exhaust herein described is particularly applicable to locomotive engines in which the main part of the exhaust is employed for assisting the chimney draft, or for feed heating purposes. Owing to the construction of locomotives, it is impossible to lead the exhaust from the Y bottom of the cylinders, or such a construction is associated with considerable difliculty.

'By arranging a separate draining exhaust,

as described, only low pressure steaml @Scapes through the draining passage 40, and all the advantages of leading theexhaust from the bottom of the cylinder are secured.

What I claim is 1. In asteam engine, the combination of a cylinder, 'a' )iston therein, a steam inlet port at the en of the cylinder, a valve controlling the passage of steam through said port, means for operating said valve, a group of exhaust ports in the upper side of the cylinder and a group of exhaust ports in the under side of the cylinder, the. total area of the lower group of ports being less than the total area of the upper group of ports, all `of said ports being covered and uncovered by the piston in its travel, and each group of ports communicating with a separate exhaust passage, substantially as described. y

2. In a steam engine the combination of a cylinder, a piston therein whose travel and form are so. proportioned relatively to the cylinder as to provide a clearance whose volume isequivalent tothe least volume into which the residual exhausted steam is to be compressed, a` steam inlet port at the lend of the cylinder, a valve controlling the passage of steam through said port meansfor' operating said valveta group of exhaust ports in the upper side of the cylinder, a group of exhaust ports in the under side of the cylinder, the total area ofthe lower group. of ports being less than the total rea of the upper group of ports, all of said ports being covered and uncovered by the piston in its travel, an exhaust pipe with which the upper group of ports communicates, and a separate chamber on the underside of the. cylinder with which the lower group'of ports communicates, said chamber being provided with a relatively small outlet, substantially p as described.

ports, a piston adapted to overrun and con-k trol said exhaust ports at and near the end of its stroke, said piston being provided with a concave end and a cover on said-cylinder having a'substantially flat inner face. In witness whereof I have hereunto set my hand in presence of two witnesses. f

' JOHANN STUMPF. y Witnesses: i

' MAX SEILER, y

T S. H. ALEXANDER.

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