US2187571A - Steam distribution and control for locomotives - Google Patents

Description

J. c; MARIS,

STEAM DISTRIBUTION AND CONTROL FOR LOCOMOTIVES 4 SheetsSheet 1 Filed Sept. 24, 1937 INVENTOR (James C. /"\nels Jan. 16, 1940.

STEAM DISTRIBUTION AND CONTROL FOR LOCOMOTIVES J. c. MARIS 2,187,571

Filed Sept. 24, 1957 4 Sheets-Sheet 2 I= v 40 Fig 5. 19A 24. 24

INVENTOR U FINES C. News J. C. MARIS Jan. 16, 1940.

STEAM DISTRIBUTION AND CONTROL FOR LOCOMOTIVES 4 Sheds-Sheet 3 Filed Sept. 24, 1937 INVENTOR James C. l mrels ATTRNEY Jan. 16, 1940. c, MARIS 2,187 571 STEAM DISTRIBUTION AND CONTROL FOR LOCOMOTIVES Filed Sept. 24, 1937 4 Sheets-Sheet 4 INVENTOR [James C. M9215 AT ORNEY Patented Jan. 16, 1940 UNITED STATES PATENT OFFICE STEAM DISTRIBUTION AND CONTROL FOR LOCOMOTIVES 4 Claims.

This invention relates generally to locomotives and more particularly to an improved system for controlling supply of steam to simple expansion engine cylinders, the invention being particularly useful in connection with high speed four cylinder type locomotives in whichthe cylinders are of the simple expansion type.

In the specific disclosure herein, the four cylinder locomotive preferably operates under a high pressure of say, 350 pounds boiler pressure, and in order to provide suificient continuous tractive power required to operate at a very high speed of say 100 miles per hour with a heavy train, it is necessary to use the high pressure steam economically and expand it down by using relatively large size cylinders, the valve gear cutting oft preferably at a very short strokesay 20% to 25%. This will give a low steam and water rate per indicated horsepower.

The necessity for using the steam economically in such a high speed and high power locomotive is because the physical size of a boiler is definitely limited in accordance with the clearance limits required for passing through tunnels, etc., which determine the ultimate size of the boiler. Hence the increase in demand for speed and power cannot be satisfied by increasing the size of the boiler, but must be obtained by operating with maximum economy in the use of steam. This problem, however, is further complicated because the large size cylinders required to operate the engine at higher speeds under the high boiler pressure will produce, during starting, a tractive force sufiicient to slip the drivers unless the supply of steam can be very closely controlled. With prior art arrangements, such close control would be difiicult to obtain by the engineman because of the extremely close limits within which the throttle valve would have to be cracked. Hence this method of cracking the throttle depends upon the variable personal equations ofthe engineman and is open to the objection that carelessness in operation or inability to control the valve with the necessary nicety of accuracy will cause the driving wheels to slip and thereby wear the tires and rails as well as placing great strain upon the locomotive mechanism together with other harmful eilects on the fire, etc., such as are well known to those versed in the art. Furthermore, the necessary steam control cannot be obtained by a multiple throttle valve because if the engine fails to start upon partial opening of the valve, then steam pressure will gradually build up to the maximum boiler pressure causing slip.- page of the wheels.

It is an object of my invention to provide in a high speed high boiler pressure locomotive employing relatively large simple expansion cylinders an improved system for economically controlling supply of steam to the cylinders and for avoiding the necessity of relying upon the ability of the engineman to control the supply of steam with a high degree of sensitivity and accuracy.

Another object is to provide an improved system for controlling supply of steam in a locomotive as above referred to whereby the engine cylinders may be supplied with steam at a maximum possible pressure substantially below boiler pressure and consequently with minimum possibility of slipping the drivers thereby facilitating starting of the locomotive and train, and thereafter allow steam to be supplied to the cylinders under full boiler pressure.

Another object is to accomplish the foregoing objects by a combination of elements constructed and arranged in a manner that is relatively simple and compact and is economical in operation and maintenance. I

Other objects and advantages will be more apparent to those skilled in the art from the follow-- ing description of the accompanying drawings in which: r

Fig. 1 is a diagrammatic sideeelvation of a locomotive embodying my improved control system, parts being broken away to show in elevation 1 certain elements of the control system;

Fig. 2 is a plan view of Fig. 1 but with the boiler removed and a part of the multiple throttle valve broken away, substantially along the line 22 of Fig. 3, to show the relation of certain elements in the control system;

Fig. 3 is a longitudinal section through the multiple throttle valve taken substantially on the line 33 of Fig. 2;

Figs. 4 and 5 are similar sections taken respectively on the lines 4-4 and 5-5 of Fig. 2; I

Fig. 6 is a vertical transverse section taken substantially on the lines B6 of Figs. 2 and 3;

Fig. 7 is a side elevation similar to Fig. l but showing a modified arrangement of my improved control system;

Fig. 8 is a plan view of Fig. 7 with the boiler removed for purposes of clarity;

Figs. 9, 10, 11 and 12 are longitudinal sections taken respectively on lines 9-9, lD--l0, H-H and Ill-l2 of Fig. 8.

In the specific embodiments of the invention such as I have disclosed herein merely for the purpose of illustrating two specific forms among possible .others that the invention might take, I

have provided as shown in Fig. l a four cylinder locomotive of the single rigid frame type such as disclosed in McCarroll Patent 1,622,917 wherein a single rigid locomotive frame i has a forward pair of cylinders 2 and a rearwardly disposed pair of cylinders 3 located midway between the ends of the frame. The frame i is rigidly connected to or formed with said cylinders and is provided with usual pedestals and spring rigging for a forward set of driving wheels t and a rearward set generally indicated at 5. Other usual locomotive elements and accessories are, of course, employed but do not enter into my present invention and hence need not be described. Also my invention is applicable to simple expansion articulated type locomotives as well as being applicable to a simple two cylinder locomotive.

A usual boiler 1 is supported in a customary manner upon frame I and has a usual steam dome B from'which steam is conducted through the well known dry pipeB to a superheater head- 'er generally indicated at 1-0.- As shown in Fig. l, the superheater header has transversely extending chambers II and 12 which are relatively shallow and to which the superheater header tubes are connected in a customary mannerbut which are not disclosed herein because they do not-per se constitute a part of my present invention. Chambers H and I2 are separated by a partition Ha having openings Hb to effect uniform distribution to chamber 1'22. Chamber l2 communicates with another transverse chamber 13, Fig. 3, one end of which communicates with a longitudinal passage M, Figs. 2,3 and 6, and thence with a chamber [5, Fig. 3, of an automatic reducing valve 'mechanism generally indicated at l6. Various types of reducing valves may be employed such as that diagrammatically disclosed herein or that shown in Patent No. 855,796, and inasmuch as such devices are well known, further. detailed description is not deemed necessary. Steam fiows from the valve chamber inlet I5 through a passage controlled by valve I1 to an upper valve outletchamber I8 and thence into a transverse chamber l9 shown in certain instances in Figs. 3 and 6. The reducing valve is is so adjusted and operated in its customary manner that it maintains 'a constant outlet pressure inchambers I8 and I9 of say 250 pounds as against the 350 pounds boiler pressure.

The remaining steam supply and control structure will be more readily understood from a description of the mode of operation of my improved system. Assuming that the engineman 'desiresto start the locomotive, he rotates a camshaft 20, Fig. 6, through a usual throttle lever in "the locomotive cab and linkage connected to an arm 2|. Inasmuch as such elements are well known, further description thereof is not necessary. Initial rotation of shaft 20 will cause a cam 22 to'raise a usual pilot valve 22a to admit low pressure steam from chamber 19 through an opening 19b to a balancing chamber 23. A series of valveplungers 24 are of substantially the same effective area as throttle valves 25 and hence the opposed steam pressure forces acting on the valves 'and plungers will be substantially balanced. Continued rotation of camshaft 20 will cause earns 26 to successively open. the throttle valves '25, thereby admitting low pressure steam from chamber I9 into a chamber 21 and thence through an outlet T 28, Fig. 2, to which the usual-steam pipes 28 areconnected. As shown in Fig. 1, the steam pipes 29 are connected to the forward pair of cylinders :through suitable an opening Ail in a partition Al, Fig. 3.

steam. As the locomotive gains speed under the relatively low pressure, a second set of throttle valves 35, Fig. 5, are then successively opened through rotation of a camshaft 36 and cams generally indicated at 31. As shown in Fig. 3, the camshafts 2i) and 38 are connected by a link 36a. for common actuation from the main throttle lever .in the locomotive cab although the angular relation of -the cams on said shafts is such that the high pressure throttle valves are not initially opened until'all of the low pressure valvesare open. As the valves 55 open, high pressure steam directly from the boiler flows through chambers 12 and i i and'an opening 31b into a chamber 38 separate from chamber l9, whereby upon opening of valves 3.5 steam is admitted to a transverse chamber 353. This chamber has free communication with chamber 2?, Fig. 6, through Hence the chambers2l and 39 are equivalent to a=single chamber communicating with the outlet pipe connection 28 leading to steam pipes 29.

.It will be understood that the full boilerpressure now admitted to chambers 39 and 21 will also cause full boiler pressure to build up in chambers 19 and I8, but this will not be detri- 'menta'l because *full boiler pressure already exists in chamber I5 beneath throttling valve ll. Hence there cannotbe any reverse flow of high pressure steam in the system after the high pressure throttle valves 35 are open. The high pressure valves 35 are subjected to balancing pressure ina chamber Msupplied withhigh pres- .sure steam through a pilot valve :33 which is x opened by camshaft 36 prior to opening of any of the valves 35.

From the foregoing description it is seen that boiler pressure is automatically reduced in passing through reducing valve H5, whereupon the engineercan readily sequentially open low pressure valves 25 without fear that sudden high pressure will build up in the engine cylinders to cause the drivers to spin. Consequently, there will be no waste of steam or other deleterious effects. After the engine has startedfull boiler pressure can be readily supplied to the engine cylinders by sequentially opening the valves 35.

In the modifications shown in '7 to 12, a pipe Ma corresponding generally to passage I Fig. 2, of the preferred form connects into an automatic pressure reducing valve Ba which, like valve l6, maintains a constant reduced pressure on the outlet side thereof. Valve H50, is located outside of the smolsebox a substantially lower level than the superheater header as shown in Fig. '7. -A low pressurepipe 8a corresponding generally to chamber l8, Fig. 3, of the preferred form communicates with a chamber its. The

remaining passage arrangement, valves and opcrating mechanism therefor are identical to that .of the preferred form and hence corresponding parts are given the samereference numerals except that'they are primed. The mode of operation is the same, and hence the .description'of the preferred form will sumce for this modification.

From the foregoing disclosure, it is seen that I have provided an extremely simple and yet highly effective throttle control system adapted to insure a convenient and positive means for supplying low pressure steam from the high pressure boiler to the engine cylinders during starting and thereafter supply steam to the cylinders under full boiler pressure. There is no necessity on the part of the engineer to attempt to use exacting control over the throttle valves in an attempt to prevent spinning of the drivers with consequent wastage of steam and in my improved system there is no possibility, in the event the engine does not start immediately upon admission of steam to the cylinders, for full boiler pressure to accumulate in the engine cylinders as would be the case with a usual throttle valve control operated in a cracked position. The automatic reducing valve in my improved system prevents any accumulation of full boiler pressure in the engine cylinders in the event that the engine does not start upon opening of the low pressure throttle valves 25.

It will of course be understood that various changes in details of construction and arrangement of parts may be made by those skilled in the art without departing from the spirit of the invention as set forth in the appended claims.

I claim:

1. In combination, a steam locomotive having a high pressure boiler and simple expansion engine cylinders, a pressure reducing valve operative to maintain a reduced substantially constant outlet pressure, a throttle valve, means for supplying steam under full boiler pressure to said reducing valve and for conducting steam from the outlet side thereof under reduced pressure to said throttle valve whereby said throttle valve is maintained completely full of steam under reduced pressure at all times so that a full volume of low pressure steam can be instantly supplied to said cylinders, means for conducting steam from the throttle valve to the engine cylinders, and means for supplying steam under full boiler pressure to said engine cylinders after the reduced pressure steam is initiallysupplied thereto.

2. In combination, a steam locomotive having a high pressure boiler and simple expansion cylinders, a transversely extending throttle valve casing having a plurality of throttle valve chambers and a common outlet therefor leading to the engine cylinders, a plurality of throttle valves in each of said chambers for variably controlling flow of steam therefrom to said outlet, means for. supplying boiler steam directly to one of said throttle chambers, an outlet at one side of said casing communicating with said boiler steam supply means, a constant pressure outlet reducing valve communicating with said side outlet, and

means located at the other side of said throttle casing for connecting said reducing valve with the other one of said throttle chambers, whereby boiler steam is first supplied to said reducing valve and then to said latter throttle valve chamber which is thereby maintained completely full of steam under reduced pressure at all times so that a full volume of low pressure steam can be instantly supplied to said outlet.

3. In combination, a steam locomotive having a high pressure boiler and simple expansion engine cylinders, a throttle valve casing having a plurality of throttle valve chambers connected to the engine cylinders, a plurality of throttle valves in each of said chambers for variably controlling flow of steam therefrom to said engine cylinders, means for supplying full pressure boiler steam directly to one of said throttle chambers, a constant pressure outlet reducing valve communicating with said throttle chamber to which full boiler pressure steam is supplied, and means connecting the outlet side of said reducing valve with the other one of said throttle chambers whereby boiler steam is first supplied to said reducing valve and then to said latter throttle valve chamber which is thereby maintained completely full of steam under reduced pressure at all times so that a full volume of low pressure steam can be instantly supplied to said outlet.

4. In combination, a steam locomotive having a high pressure boiler and simple expansion cylinders, a transversely extending throttle valve casing having a plurality of transversely extending valve chambers, transversely extending chambers beneath each of said valve chambers and terminating in a centrally disposed longitudinally extending common outlet leading to the engine cylinders, a plurality of sequentially operated throttle valves in each of said throttle valve chambers for variably controlling flow of steam therefrom to said outlet, a main steam, supply header having a steam pipe passage at one end and a steam supply chamber at its other end extending transversely of said throttle valve casing adjacent to and communicating directly with one of said throttle valve chambers whereby full boiler pressure steam can be supplied to said outlet, a constant pressure outlet reducing valve communicating with said header and throttle valve chamber to which full boiler pressure steam is supplied, and means connecting said reducing valve with the other one of said throttle valve chambers whereby boiler steam is first supplied to said reducing valve and then to said latter throttle valve chamber which is thereby maintained completely full of steam under reduced pressure at all times so that a full volume of low pressure steam can be instantly supplied to said

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