US1974200A - Steam engine - Google Patents

Description

Sept 18, 1934. J. TITUS El AL 1,974,200

STEAM ENGINE Filed May 2 1926 2 Sheets-Sheet l Suva l'ozs Sept. 18, 1934. H. J. TITUS ET AL STEAM ENGINE 2 Sheets-Sheet 2 Filed May 24, 1926 Patented Sept 18, I934 starts Railway Supply Company, New York, N. Y., a corporation of Delaware Application May 24, 1926, Serial No. 111,180

6 Claims.

This invention relates to steam engines and is particularly applicable to locomotives.

It has for its primary object the provision of means for starting a steam engine which is equipped with what is known in the art as a limited cut off.

The invention is illustrated in the accompanying drawings as being applied to a locomotive and the description, therefore, will particularly relate 10- to locomotive practice although it is to be understood that the invention might be applied to other steam engines.

For purposes of economy in steam consumption as well as for other reasons familiar to those skilled in the art, it is frequently customary to set the valves of a locomotive so that at what is known as full gear position the valve will give a cut off at half stroke, for example, or at some other portion of the stroke greater than half stroke. It is therefore obvious that even in three cylinder engines there may be positions of the parts when the engine stops at which the starting effort will be considerably less than required. Our invention therefore relates to means for starting a limited cut off engine and to this end it is an-object of the invention to provide a supplementary or auxiliary steam supply mechanism together with means for properly controlling it so that it will not interfere with the normal limited cut off operation of the engine at higher speeds. Furthermore it is an object of our invention to provide a starting device which will make it possible to employ cut oils of less than 50% if so desired. Of course with our de- Vice it is also possible to obtain greater tractive effort at starting especially over certain portions of the cycle and it will be possible to provide for more uniform torque at slow speeds than is obtainable under present practice.

How the foregoing together with other incidental advantages may be obtained by our invention will now be described in connection with the accompanying drawings which illustrate a preferred embodiment and in which 7 Fig. l is a partial diagrammatical side elevation of a locomotive with our improvements applied thereto and with certain portions of the apparatus broken away to illustrate details; and

Fig. 2 is an enlarged view similar to that which is shown at the forward end of Fig. 1 in order to make the details more clear. r

The locomotive A is, shown as being supplied with the usual cylinders 1 and pistons 2 which .can be connected in any well known manner (not shown) to the wheels or a driving axle. The

steam passages 3 and 4 are controlled by the piston valve 5, the steam entering at the center thru chamber 6 and exhausting at the ends 7 and 3. Steam enters the chamber 6 thru the usual steam pipe 9 and is discharged by suitable connections from the ends I and 8 to the exhaust passage 10.

The parts so far described are all old and well known in the art and, therefore, need not be described in greater detail. The valve 5, for purposes of illustration, will be assumed to have been set so that in what is known as full gear position it will give a cut off at half stroke of the piston 2. The piston 2 is illustrated at the extreme forward limit of travel and is'just on the point of returning to the other end of the cylinder. The valve 5 is moving forward and is just on the point of opening the passage 4 to the sup-ply chamber 6. During the first half of the return stroke of the piston 2 the valve 5 will move forwardly to completely uncover the passage 4 and then will return to the position indicated in order to cut off the steam supply. Under normal conditions the balance of the stroke of the piston 2 will be accomplished by what is known as the expansive force of the steam.

However at starting our improvements provide means for supplying the piston 2 with steam throughout practically its entire stroke in order to obtain the advantages hereinbefore mentioned.

It will be noted that the passages 3 and 4 are annular passages and to each is connected a supplementary steam supply passage 11 and 12 respectively. Steam for these passages is brought from the steam pipe 9 thru the conduit 13 which delivers the steam to the chamber 14 of the valve device B. Here it is subjected to the control of the supplemental inlet valve 15 which, when opened,'establishes communication between the chambers 14 and 16, the chamber 16 communi- 5 eating with the two passages 11 and 12 subject however to the distributing mechanism to be described below. I

We arrange to have the supplemental inlet valve 15 under the direct control of the engineer in the locomotive cab 17. This is accomplished by means of an air valve 18 which can be operated by a lever 19. When the lever 19 is pushed downwardly the valve 18 is opened so that air pressure from the reservoir 20 thru the conduit 21 can reach the upper face of the piston 22 which is connected to the valve 15. The piston moves downwardly under the pressure of the air in order to open the supplemental inlet valve 15. The spring 23 and the steam pressure on the under 116 in Fig. 2.

face of the valve 15 serve to close it when the air pressure is relieved.

The distributing mechanism in the chamber 16 comprises the piston valves 24 and 25 which respectively control the passages 12 and 11. In the absence of steam pressure in the chamber 16 the valves 2% and 25 are held in their upward position so as to cut off the flow of steam thru the pipes 11 and 12 by means of the springs 26 and 27. Each valve 2425 is provided with a stem 28 which projects downwardly toward the controlling collar 29 slidingly mounted upon a forward extension-30 secured to th piston valve 5. g

The stem 30 is supported at its outer end by the bracket 31 and at each side of the collar 29 it carries a stop shoulder 3233.

The operation is as follows assuming that the locomotive is starting from a dead stop with the piston 2 and the valve 5 in the position indicated The piston on the other side of the locomotive (not illustrated) will, of course, be doing the initial work. However, just as soon as motion starts the valve 5 will move forwardly and steam from the chamber 6 will flow thru the passage 4 in order to force the piston 2 rearwardly.

The valve 5 having already been traveling in a forward direction will have brought the stop 32 against the left hand end of the collar 29. The collar 29 will, therefore, be carried forwardly so that the stem 28 of the valve 24 will be in a position to clear the upper surface 34 of the collar and come down upon the surface 35 to the left of the surface 3 1. The engineer has, of course, operated the valve 18 so as to open the supplemental inlet valve 15 and the steam pressure entering the chamber 16 forces the piston 24 downwardly, as described to bring its stem 28 down into contact with the surface 35. This of course opens the supplementary passage 12 so that steam is being supplied thru such passage as well as thru the normal passage 4.

Zhis condition will continue thru the balance of the forward stroke of the piston valve 5 and until the piston valve 5 has returned to the position illustrated in Fig. 2. At this time as previously stated the main piston 2 will have travelled half of the distance toward the rear end of its stroke. Cut off of the passage 4 will then take place so that the normal flow of steam from the chamber 6 will not take place. However at the same time the valve 5 can still travel toward the left before it moves the collar 29 to the left in order to once again bring the surface 34 beneath the stem 28 in order to close the supplementary passage 12. The reason for this is that there is lost motion between the stops 32 and 33 indicated at the point X. It is not until the stop 33 is brought into contact with the right hand end of the collar 29 that it will be moved to the left in order to close the passage 12 as described and the movement of the piston valve 5 is so controlled by the valve mechanism (in the usual way, not illustrated herein) that this action will not take place until near the end of the return stroke of the piston 2. The piston therefore will be receiving steam thru the passage 12 during the time that normal supply thru the passage l is out oif, the passage 11 on the other hand being closed by the piston valve 25 whose stem 28 still remains upon the upper surface 3 of the collar 29. It will be seen, therefore, that the supply of steam through the supplementary passage 12 does not begin untilapa proximately the moment when the main passage 4. is being opened and that the supplemental supply is then continued after cut off at the main passage until approximately the point of release at the main passage. In this way both pare-admission and wastage of steam are prevented.

At the other end of the stroke of the piston 2 just the reverse operation takes place the valve 25 opening to permit steam to reach the left hand end of the piston 2 thru the supplementary passage 11 while the valve 24 closes or cuts off the supply of steam thru the passage 12. The V stem 28 of the valve 25 rides down upon the surface 36 to the right of the surface 34, the surface 36 corresponding to the surface 35 at the other end. Between the surface 34 and the sur. faces 35 and 36 there are inclined faces 37 over which the stems 28 can easily ride.

It might be stated that the valve mechanism B as a whole may be mounted in any suitable manner'as by the bracket 38a. The valve rod extension 30 is suitably packed, of course, at the point where it enters the valve chamber.

It should be mentioned that stops 38 are provided to limit the upward movement of the piston valves 24and 25.

It will be seen that the movements of the valves 24 and 25 are so synchronized with the movement. of the main piston valves 5 as to permit the supply of steam which they control to enter the cylinders 1 at the proper times. This synchronization takes place by virtue of the fact that the control mechanism for the valves 24 and 25 is operated by a moving part of the locomotive directly associated with the movement of the locomotive valve, in this instance by the extension 30 connectedto the valve itself, although some other arrangement might be adopted.

Furthermore it will be seen that the cam 34 is of such a length in proportion to thetravel of the main valve 5, as to prevent opening of the piston valves 24 and 25 except during periods of long out off when the travel of the main valve 5 is sufficiently great to bring the cam surface 34 out from under the stems 28. During periods of short cut off or when the reverse gear is hooked back, as it is expressed by those skilled in the art, the travel of valve 51s not great enough to permit the valves 24 and 25 to be opened. In this way our invention positively prevents operation of the locomotive in a direction opposite to that for which the reverse gear may be set as sometimes happens with limited out off locomotives equipped with the usual starting ports.

The apparatus is extremely simple and will make it possible to obtain greater tractive effort at starting over certain portions of the cycle Where the tractive elfort has heretofore been low and at the same time it will make possible a more uniform torque at slow speeds as well as permit the use of cut oifs of less than 50% if so desired. As will be apparent to those skilled in the art this arrangement of auxiliary steam supply mechanism has many advantages over the supplementary port mechanism normally employed in limited out off engines where the supply of steam which is possible at all .times thru such auxiliary ports has a tendency to overcome or overbalance, so to speak, the advantages incident to the employment of such ports at low speeds. Furthermore, with our device it is possible to stop the flow of steam entirely after a start has been made. This the engineer can accomplish simply by closing the valve 18. When this takes place the valves 24 and 25 are moved upwardly out of the path of the collar 29 so that the high speed reciprocation of the parts attached to the valve 5 will not be liable to cause damage. Even at slow speeds the use of auxiliary ports without the mechanical controlling devices which we have disclosed prove to be a disadvantage in that they affect the compression period of the stroke of the pistons 2. Many other advantages will occur to those skilled in the art.

We claim:

1. A distributing apparatus for a locomotive starting device of the character described comprising in combination, a member moving with a locomotive valve, a pair of stops on said member, a collar slidable between the stops, a steam supply chamber, a conduit between said chamber and each end of a locomotive cylinder, and a piston valve controlling each of said conduits having a stem projecting toward said collar and movable thereagainst under the pressure of the steam, said collar normally holding said piston valves in position to close said conduits but adapted to be moved by said stops to permit movement of said piston valves to open said conduits.

2. In a steam locomotive having a cylinder, a piston, a main valve, and an adjustable valve gear for operating and reversing said main valve and altering its cut-oii, said main valve and said valve gear, when in full-gear position, being set so as to cut off the supply of steam to the cylinder at a ercentage of the piston stroke which is substantially less than the customary maximum; the combination with said adjustable valve gear of means providing a by-pass around and independent of said main valve to the cylinder, supplementary valve means independent of said main valve but actuated by said adjustable valve gear for opening and closing said by-pass in timed relation to the piston movement to admit steam to the ends or" the cylinder independently of said main valve throughout approximately the customary maximum stroke of the piston, and means for effecting the starting and stopping of said supplementary valve means to render said by-pass operative or inoperative but without afiecting the cut-oii of the main valve.

3. In a steam locomotive having a cylinder, a piston, a source of steam supply, a steam passage to each end of the cylinder, main valve means for controlling said passages, and an adjustable valve gear for operating and reversing said main valve means and altering its cutoff, said main valve means and said valve gear being set so as to limit the supply of steam through said passages when in full-gear position; the combination with said adjustable valve gear of by-pass means for delivering steam to the cylinder independently of said main valve means, supplementary valve means independent of said main valve means for controlling said by-pass means, said supplementary valve means being controlled by the said adjustable valve gear so as to cut off the supply of steam through the by-pass means after cut-off by said main valve means, and means for rendering said supplementary valve means and the by-pass which it controls operative or inoperative as desired without affecting the cut-ofi of the main valve means.

4. In a locomotive having a cylinder, a piston, a source of steam supply, a main valve, and an adjustable valve gear for operating and reversing said main valve and altering its cut-off, said main valve and said valve gear being set so as to limit the supply of steam when in full-gear position; the combination with said adjustable valve gear of by-pass means around said main valve, supplementary valve means independent of said main valve for controlling said by-pass means, a cam means operated by said adjustable valve gear for actuating the supplementary valve means in timed relation to the piston movement, said actuating means being set to close the supplementary valve means after cut-off by the said main valve, and means for rendering said cam means effective or ineffective to actuate said supplementary valve means without affecting the cut-off of said main valve.

5. Means for starting a limited cut-off steam locomotive having a cylinder, a piston, a steam chest, main steam supply ports and passages, a main steam valve set to give a limited cut-cit when in full-gear position and an adjustable valve gear for operating and reversing said main valve and altering its cut-01f; said means including, in combination with said adjustable valve gear, supplementary passages for supplying steam to the cylinder independently of the main valve, starting valve means independent of the main valve for controlling said supplementary passages, means actuated by said adjustable valve gear for controlling the opening and closing of said starting valve means in timed relation to the piston movement to admit steam to the cylinder throughout sufiicient of the piston stroke to effect starting of the locomotive, and means for initiating or discontinuing the said operation of the starting valve means in order to render said supplementary passages effective or ineffective without affecting the cut-off of the main valve.

6. Means for starting a limited cut-off steam locomotive having a cylinder, a piston, a steam chest, main steam supply ports and passages, a main steam valve set to give a limited cut-off when in full-gear position and an adjustable valve gear for operating and reversing said main valve and altering its cut-off; said means including, in combination with said adjustable valve gear, supplementary passages for supplying steam to the cylinder independently oi the main valve, starting valve means independent or" the main valve for controlling said supplementary passages, means actuated by said adjustable valve gear for controlling the opening and closing of said starting valve means in timed relation to the piston movement to admit steam to the cylinder throughout sumcient of the piston stroke to effect starting of the locomotive, said starting valve means being shiftable into and out of engagement with said means for controlling the opening and closing thereof, and means for so shifting the starting valve means in order to render said supplementary passages eiiective or ineffective without affecting the cut-oii of the main valve.

I-IUBERT J. TIT'US. JOHN S. WALLIS.

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