May 8, ,668,927

Transcription

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5 O Patented May 8, UNITED STATES PATENT OFFICE. JoHANN STUMPF, OF BERLIN, GERMANY. NoNCONDENSING STEAM. ENGINE... Application filed November 10, 1920, serial No. 423,201, and in Germany October 14, with cut-off at three different positions of The invention relates to steam engines, and is especially applicable to non-condens the piston, ing steam engines. Fig. 5 is a cross-section through the cyl The object is to provide improved method inders and a Smokebox of a locomotive. and means for transforming pressure energy Fig. 5" is a top plan view of formation 11. of exhausting steam of a plural cylinder Fig. 6 is a part elevation part section of a steam engine into kinetic energy and utiliz cylinder and valve gear therefor. ing said kinetic energy derived from the ex Fig. 7 is a diagrammatic section showing hausting steam of one cylinder in withdraw a two-cylinder engine with the cranks at ing residual exhaust from another cylinder. 90, with 75% release, Fig. 7 showing the The invention is especially applicable to cyl Crank arrangement. inders in which steam has a uni-directional Fig. S is a similar view showing a two flow. s cylinder engine with cranks at 90, with The invention comprises the method of 90% release, with auxiliary exhaust, Fig. 8: utilizing the entire pressure of the exhaust showing the crank arrangement. - of one cylinder at the point of release, that Fig. 9 is a similar view showing a three is the point at which the exhaust port be cylinder engine with cranks at 120 with gins to open, to draw exhaust steam from 90% release, Fig. 9 showing the crank ar another cylinder. l'angement. This method involves an overlap of the Similar numerals refer to similar parts exhaust periods of two or more cylinders in throughout the several views. such manner that the maximum velocity in In the diagram, Fig. 1 of a crank circle the exhaust of one cylinder is available for of a twin cylinder unaflow engine, is shown acting upon the residual exhaust of another the time of opening the exhaust ports, con cylinder M trolled by the piston, with an advance of The invention also comprises improved 25% in the lead of the exhaust, with cranks means for effecting the method above de at 90.. fined, including an ejector, and means for In this diagram, a. and b represent the cir preventing the expansion or loss of Velocity cular motion of the engine when the ex until after the exhaust has passed the ejec haust ports of one cylinder are open, and 6 tor; nozzle follmations for preventing loss and direpresent the circular motion of the in transforming initial pressure energy into engine when the exhaust ports of the other kinetic energy, and diffuser formations for cylinder are open. changing kinetic energy into pressure energy It will thus be seen that the opening of the in order to discharge against the atmosphere, and in combining with the means above re cited, an elongated piston for covering the main exhaust, ports at all times except near the end of the stroke. The invention also includes exhaust valves so timed that the ex haust of one cylinder will open at a prope' interval before the final closing of the ex haust of another cylinder. The invention also covers other details and formations herein particularly described. Referring to the drawings which illustrate merely by way of example, suitable and pre ferred means for effecting my invention;-- Fig. 1 is a diagram showing the time of opening of the exhaust ports of a twin cyl inder uniflow engine Fig. 2 is steam diagram of said engine. Fig. 3 is a diagram showing the time of opening of the exhaust ports of a triple cyl inder uniflow steam engine..... ; Fig. 4 comprises three indicator diagrams, exhaust ports of opposite cylinders overlap to the extent, of the shaded parts e, f, g and h; or that the exhaust port of one cylinder is opened before the exhaust port of the op posite cylinder is closed. - The entire initial energy of the exhaust at the point of release is utilized in drawing residual exhaust steam from the opposite cylinder just before its exhaust port closes. The diagram, Fig. 2, shows an indicator card in black lines, with the expansion curve carried to the exhaust pressure shown by the shaded portion. The shaded portion A shows the amount of steam exhausted dur ing the simultaneous opening of the ex haust ports of both cylinders and represents the energy which is utilized to draw off the residual steam of the opposite cylinder and drop the pressure in the opposite cylinder as indicated at...l.m. C. represents the increase in the work done in the cylinder due to the lowering of the pressure from l to m SO 90 OO O

6 () will certainly entail a vacuum of 50%. This, in combination with the commencement of the compression at 75%, allows a clearance space of the same size as used in Ordinary locomotives. The vacuum produced in a triple cylinder engine will always be larger than in a twin cylinder engine, as the resid ual steams better drawn out by the other cylinders than by the one cylinder. The short length of the usual exhaust pipe will not allow too much suction upon the residual steam of the same cylinder... In a triple cylinder engine the exhaust will also show the greatest uniformity, and, when used with a locomotive, will produce a good intensive and effective combustion. There will be a substantial reduction of steam consumption and a substantial in crease of the capacity of the engine. A cut of at different positions of the piston will entail different vacua and different compres sions as indicated in Fig. 4. In the cross-section view, Fig. 5, the ex haust nozzles 3 and 4 are placed in the cyl inder wall. The area is first smoothly re duced and then smoothly and gradually en larged. Only two nozzles, 3 and 18, and 4 and 16 are arranged in the wall of each cyl inder; one being continued by a pipe lead ing to the ejector-union 7, 8, 9, 10, 11, and the common Smoke stack 15, 16, 17. The other nozzles 18 and 19 lead by other pipes 20, 21 to heating devices not shown. In the triple cylinder engine, three exhaust pipes meet at the union, the cross-section of which is almost tripled in comparison with the cross-section of one single cylinder ex haust pipe. - In Fig. 6, the cylinder is shown with The shaded portion B indicates that part single beat valves 22, 22", a Walchaert gear of the steam left in the cylinder, which is and an actuating cam with rollers. The re exhausted by its own pressure after the ex Sulting motion of the Walchaert gear is com haust port of the opposite cylinder has been inunicated by rod 23 to the lever 24 upon closed. shaft 25, mounted in a casing 26, and bear The diagram, Fig. 3, shows the time of ing a swinging cam 27 provided with curved opening of the ports controlled by the pis faces acting upon the rollers attached to tons of a triple cylinder uniflow steam engine swinging levers 28, 28. These levers trans with an advance of ten per cent in the lead mit motion to horizontal slide pieces 29, 29, of the exhaust, and with cranks at 120. which push the spindles of the single beat The arcs M, N, P, Q, R and S show the time valves 22, 22. The pistons 31 are movable in the cycle when the exhaust valves are in a cylinder formation 32 arranged in the open. The shaded sections show the over central part of the casing 26. Steam or lapping of the exhaust valve openings. The compressed air may be introduced into the time of opening of the exhaust of one cyl space between the pistons 31, by means of a inder is always partially covering that of pipe 30, to press them apart, thus engaging another, so that, at all times, residual steam elements 29, 29' and opening the inlet valves is drawn out from one of two other cylinders. in order to remove all resistance for the The diagram, Fig. 4, represents three indi locomotive when drifting or empty running. cator diagrains or cards, with cut-off at three By making the advance in the lead of the different positions of the piston. A cut-off exhaust in a uniflow cylinder as large as 25%, at 44% gives sufficient exhausting energy to the length of the piston may be reduced and produce an exhaust pressure of 0.68 atm., consequently the length and weight of the abs., corresponding to a vacuum of 32%, if cylinder. In fact the cylinder has about ample losses by friction etc., are assumed in the same weight as an ordinary cylinder. the calculation. A cut-off at 60% or 70% The single beat valves are tight against high pressure, are very light and simple and need no lubrication. The exhaust ports 3 and 4 in the cylinder Y'alls, which are controlled by the piston, are made in the form of steam nozzles which have the effect of transforming pressure energy of the steam into kinetic energy. The form of these nozzles, as shown in Fig. 5 at 3 and 4, as well as the form of the piston as shown in Fig. 6, are made to cooperate so as to give good nozzle efficiency during the time of partial uncovering of the ports. Both may be adapted as to shape and size so as to give those cross-sections of free area required by the decreasing difference of pressure. - By combining the exhaust pipes of two or more cylinders, in an ejector like formation, a partial vacuum is created in one cylinder by the action of the exhaust from another cylinder or cylindel's. The position of the cranks at ninety degrees in a twin cylinder engine and of one hundred and twenty de grees in a triple cylinder engine will favor this suction action, if sufficient advance on the lead of the exhaust is used; twenty-five per cent will answer all requirements in two cyl inders, and ten per cent in three. This will correspond to a release at seventy-five and ninety per cent of the stroke of the piston, generally required for locomotives with two or three cylinders respectively. By release or point of release is meant the point at which the exhaust port begins to open, thereby releasing the exhaust steam from the cylinder. It is important that the entire pressure of the exhaust at the point of re lease, be utilized in order to produce the maximum velocity, and that the exhaust s

7 'shall not be permitted to expand beyond that incident to its passage through pipes 5 to smooth internal surfaces, with no or sudden changes in directionar 6 to the ejector. Therefore the exhaust gon The arrangement should be such t nections are so designed that there shall be transformation of the resi no pressure or velocity losses, due to unnec energy into speed energy, the transmission of essary expansion., - That part of the exhaust steam flowing the same, the impact of steam from one with the highest speed from one cylinder, cylinder with the residual steam of another cylinder and the impact of steam with the will just meet with that part of the exhaust combustion gases, and the transformation of steam from the other cylinder flowing with the resulting speed energy of the mixtur the lowest speed. into pressure energy at atmospheric pres The nozzle formation is shown as having sure i ured with them minefficiency its most restricted part in the cylinder wall, Where it is desired to secure a lengthened as at 3 and 4, Fig. 5. This position is op time for the exhaust at the cylinder, near tional so long as it is located before the the ends, valves may be provided which are ejector union so that all pressure energy controlled by the piston, as shown in Fig. S. will be transformed into speed energy before - While the invention is especially appli said union, where the cross-section should on-condensing steam engines, it cable to : 3: W.'; ' ' be enlarged to secure good suction. After Will be obvious to those skilled in the art, the ejector union, the cross-section of the that the improvements herein described will combined exhaust pipe should be gradually also be applicable to other engines using increased up to the highest end, which shall expansive medium having high initial pres have the largest cross-section, as shown in sure and subsequent expansive force. Fig. 5. As a rule the smallest cross-section While the invention is especially adapted is in the cylinder wall, the largest at the end for locomotives, it may be used to great ad of the combined exhaust pipe. This is al vantage for similar machinery, such as steam together different from the usual practice tractors, steam vehicles and common ex in locomotives. haust steam engines with two or more In the diffuser thus realized in the com cylinders.. bined exhaust pipe, the equalized flow of It is known that non-condensing uniflow exhaust steam is transformed into exhaust steam engines ordinarily require a large clear steam with less speed and higher pres ance space on account of the great length of sure. Just sufficient speed is left to pro compression and on account of the pressure duce sufficient air draft in the furnace. with which the compression is started. There Exhaust steam and combustion gases are is consequently the disadvantage of excessive thus mixed in the formation 17, Fig. 5, clearance space and a large steam consump forming a flow of mixture, which will be tion. This disadvantage can be substantially partially transformed into pressure energy reduced either by reducing the terminal ex in the diffuser of the chimney 15. haust pressure or by increasing the initial It is important properly to proportion the pressure or by combining both. size of the smallest area of the different noz The advantage therefore of the present zles at the cylinders. For the average production of steam, with about twenty-five method and means over the common prac tice, is that, instead of an over-pressure, a per cent advance in the lead of the exhaust, partial vacuum, up to one-half atm. is they should offer such area as to secure a created in the exhausting cylinder. This flow of steam during nearly the whole time decreases the steam consumption and yet of the opening of the exhaust port. In this leaves sufficient velocity of exhaust steam, manner the greatest unifornity in the con through the Smoke stack to produce the re bined flow of steam and the greatest suck quired draft in the fire-box of the locomotive. ing action will be obtained. It is preferable, when the exhaust is used to produce draft in the furnace, to use two diffusers, one 10, after having taken up the residual steam of a cylinder or cylinders, and the other 15, after having taken up the combustion gases. The partial vacuum in the exhaust of the uniflow cylinder, will in itself increase the efficiency and capacity of the steam engine, because the required clearance space is sub stantially reduced, the compression also is changed, so that great compression is com bined with small cut-off and small compres sion with large cut-off, as it should be. All exhaust piping should be made with The energy for accomplishing this result is taken from that part represented in the diagram Fig. 2, as lost by incomplete ex panslon. What I claim is:- 1. In a plural cylinder engine, the com bination of means comprising exhaust ports and passages having nozzle formations to prevent loss in transforming the initial pres sure energy of the exhaust to kinetic energy and means comprising an ejector for utiliz ing said kinetic energy derived from the ex haust of one cylinder to draw the exhaust from another cylinder. 2. In a plural cylinder engine, the con bination of means comprising exhaust ports is ()

8 4 and passages having nozzle formations to prevent loss in transforming the initial pressure energy of the exhaust to kinetic energy, means comprising an ejector for utilizing said kinetic energy derived from the exhaust of one cylinder to draw the exhaust from another cylinder, and means comprising an aditional diffusel for chang ing kinetic energy back to pressure energy lo for discharging against atmosphere. 3. In a plural cylinder engine having main exhaust ports controlled by the power pis ton operating so that, when exhausting, there shall be no opening of the main exhaust 15 port or ports, except the exhaust opening from the exhausting side of the cylinder. the combination of means forming an ejector common to all exhaust ports, and port con trolling means so timed that the exhaust from one cylinder will operate to withdraw the exhaust steam from another cylinder. 4. In a plural cylinder engine having main exhaust ports controlled by the power piston operating so that, when exhausting, there shall be no opening of the main ex haust port or ports, except the exhaust open ing from the exhausting side of the cylinder, the said cylinders also having supplementary exhaust ports and valves controlling the same, the combination of means forming an ejector common to all exhaust ports, and port controlling means so timed that the exhaust from one cylinder will operate to withdraw the exhaust steam from another cylinder. In testimony that I claim the foregoing as my invention I have signed my name. JOHANN STUMPF