US1870303A - Steam engine - Google Patents

Description

Aug. 9, 1932 H. J. TITUS ET AL STEAM ENGINE Filed J1me 1926 2 Sheets-Sheet l 1932 H. J. TITUS ET AL 1,870,303

STEAM ENGINE Filed June 18, 1926 2 Shets-Sheet 2 INVENTORS 1 TTORNE Y6 Patented Aug. 9, 1932 @ATEF? @FF'IQE.

HUBER'I' J. TITUS, OF PATERSON, NEW JERSEY, AND JOE-IN S. WALLIS, OF NEW YORK, N. Y., ASSIGNOES TO FRANKLIN RAZLVJAY SUPPLY COLWIPANY, 015 NEW YORK, N. Y.,

A CORPORATION OF DELA'VVABE STEAM: ENGINE Application filed June 18,

This invention relates to a steam engine and is particularly applicable to locomotives which are equipped with what is now well known in the art as the limited cut-off. liocomotives of this type have a high piston thrust up to the point of cut-off. The steam then acts expansivelythroughout the remainder of the stroke, giving a gradually reduced piston thrust after the point of cut-off.

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

Our invention particularly relates to the provision of a starting mechanism for limited cut-oil locomotives. 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. This is especially true in any limited cut-off locomotive, wherein the boiler pressure or cylinder diameter has been increased suiiiciently to give power at slow speeds equivalent to a full gear locomotive with less pressure or smaller cylinders. "Vith such a limited cut-o locomotive it is necessary to pro vide a suitable means for temporarily giving the equivalent of a longer cut-off for starting purposes. When the boiler pressure or cylinder diameters have been increased as above indicated and are used in conjuncti n with a means for giving a longer cut-off for starting, there will he positions of course where the turning moment becomes excessive so that the wheels will slip. To state the matter in another way if a proper starting means is supplied it is possible to make a locomotive with a factor of adhesion which would normally cause slippage at starting but which, of course, will greatly increase the efficiency of the locomotive after a start is once obtained.

With the foregoing introduction the objects of our invention will be better understood and it can be said that we provide a 1326. Serial No. 118,813.

starting device for a limited cut-off locomotive which will reduce the pressure from the boiler sufficiently to avoid slipping while the steam is being supplied thru such starting device. In other words we provide a starting device which will give preferably the same maximum tractive effort at the moment of starting as would afterwards obtain when moving at slow speeds.

It is a further object of the invention to provide for a constant high pressure in the steam chest of the locomotive with a relatively low pressure in the cylinders at times when the main port is closed and steam is being obtained from the auxiliary starting device.

A further object of our invention is the provision of a steam engine which will greatly decrease the consumption of steam and fuel for the same power. Ne also aim to give an increased average tractive effort with approximately the same starting effort and rotative effort durin the entire cycle and to provide for a higher tractive effort at speeds where the evaporation of the boiler is the controlling factor.

flow the foregoing together with other advantages which may appear hereinafter or are incident to our invention are obtained will appear in connection with the following description of the accompanying drawings which illustrates our invention in a preferred form. Figure 1 is an enlarged view of the forward end of a locomotive illustrating the usual piston and valve construction in section with our improvements applied thereto and Fig. 2 is a similar view showing the positions of the parts just after the main valve has cut off the main steam port at the right.

The drawings show the usual piston and cylinder 1 and 2, steam ports 3 and 4 and piston valve of the central admission type the steam entering thru the steam or dry pipe 6 and chamber 7. Exhaust takes place at the ends of the valve thru passages 8 and 9 which communicate with the exhaust cavity 10 leading to the nozzle not shown. The piston 1 is shown at the forward end of its stroke in the cylinder 2 and 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 1. The piston 1 is just on the point of returning to the other end of the cylinder and the valve 5 is still moving forwardly and is just on the point of opening the passage 4. During the first half of the return stroke of the piston the valve 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 will be accomplished by what is known as the expansive force of the steam.

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. Each of these passages is controlled by a valve 13 and constitutes a by-pass around the valve for the purpose of supplying the piston with steam when starting. The passages 11 and. 12 supply steam from the boiler and may be connected to the steam pipe 6 as shown.

In order that the valve 13 may be opened fluid pressure is introduced to the face of the piston 14 in the upper cylindrical part 14a. This will move the valve plunger 16 downwardly against the top of the piston 17 which in turn forces the valve 13 to its open position against the pressure of spring 18 provided, of course, that the pressure below the piston 17 not high enough to overbalance the pressure on the piston 1 1-. The fluid pressure on the face of the piston 14 is introduced thru the pipes 15 and 1511 the pipe extending, for convenience, back to the cab of the locomotive where an operating valve 19 is provided for the convenience of the en gineer. By depressing the operating lever 20 the valve 19 can be opened so as to introduce the pressure to the pipe 15 from any suitable source of supply 21.

It will be apparent, therefore, if there be one hundred pounds pressure on the face of piston 14 acting to open the valve 13, that just as soon as one hundred pounds of steam pressure accumulates on the face of the isto'n 17 the two pistons 14 and 17 will be balanced and any slight increase of pressure on the piston 17 will immediately cause the valve 13 to close. In this way no more than approximately one hundred pounds pressure can be introduced to the face of the piston 1 in starting the locomotive. Just as soon as astart has been made the danger of slipping will be overcome and the engineer can permit the valve 19 to close in order to throw the starting device out of operation because the starting device is intended to function only for a comparatively short period of time.

For any given installation the pressure applied to piston 14 should, of course, be such as will give the desired starting pressure on the main piston 1 which is preferably as high as possible but just below the point at which the locomotive would slip its drivers. It will be seen, however, that to meet the conditions of difierent installations or any change in a given installation it would be a very simple matter to alter the point at which the valve 13 will be closed simply by altering the pressure delivered to the face of piston 14;. The valve 13, therefore, may be termed a pressure set valve since it is possible to vary the time at which it will be closed simply by changing the pressure on the piston 14.

In this connection it will be understood, of course, that an engineer in starting a locomotive docs not immediately open the throttle wide especially if his train is a heavy one. On the contrary, he carefully cracks the throttle a little at a time so that the full boiler pressure will not immediately be effective in the steam pipes 6 leading to the chests and the cylinders. In this way he is generally able to keep the pressure in these parts considerably below the boiler pressure until after the train is well started and all danger of slippage is past.

WVith a limited cut-off locomotive, such as is involved in this disclosure, slippage at start is much more likely to occur than with the regular type of: locomotive as explained above and even with the greatest care in opening the throttle an engineer might very well permit a pressure to accumulate which would be suflicicnt to cause slippage. But with our improvements it is impossible to deliver more than a certain predetermined pressure to the cylinders thru the starting passages 11 and 12 because the valves 13 will close just as soon as the predetermined pressure is reached.

In order to start a train it is, of course, necessary that both pistons be delivering power which, as is well known to those skilled in this art, is not possible in all positions of the parts with a limited cut-oil locomotive. Our improved starting device is intended to supply steam only long enough to get the main valve oil center position so that the main port is uncovered. lVhen this is effected danger of slippage is generally past.

It will be seen, therefore, that our starting device will never deliver steam to the cylinders when the main port is open unless, possibly, for a very short period of time when the pressure coming in through the steam pipe 6 is below the predetermined pressure at which the valves 13 will close. It is not necessary to use the starting device once the locomotive has been moved to the point in the cycle where the main port is opened.

One other portion of the apparatus remains to be explained, namely, the distributing mechanism indicated as a whole by the character 22. In this connection we should like to note that this distributing mechanism is in :a hand pipe 150.

all essential particulars the same as the distributing mechanism illustrated in our coling application No. 111,180, filed May 1926 to which application reference may be had if so desired.

This distributing mechanism comprises the body 23 supported in any suitable manner as upon the bracket 24. Its interior chamber 25 is provided with a pair of cylindrical pockets 26 in each of which is mounted a piston 27 having a plunger 28 which projects downwardly toward a collar 29 slidably mounted upon the rod 30 between the stops 31 and 32. The rod 30 is carried as a forward projection of the piston valve 5, the outer end being supported or mounted in any suitable manner as in the upturned portion of the bracket 33.

The supply pipe 15 delivers the fluid pressure (preferably air) to the chamber 25 above the tops of the pistons 27 and these pistons 27' control the outlets to the pipes 15a leading to the reducing valves 13 already described. In the absence of pressure in the chamber 25 the pistons 27 are normally held upwardly in a retracted position so as to cover the outlets to the pipes 15a and with their stems 28 clear of the collar 29.

The collar 29 has a raised surface 34 and two lower surfaces or faces 35 one at each side.

When the engineer introduces the pressure to the chamber 25 the pistons 27 are forced downwardly against the face 34 of the collar 29 and as this collar 29 is moved forwardly by the piston valve 5 thru the medium of the stop 31, the stem 28 of the left hand piston 27 will ride downwardly to the lower face 35 thus opening the outlet to the left This will cause the valve 13 to be opened in the manner already described so as to introduce starting pressure to the piston 1. In the reverse direction of travel of the collar 29 the same action takes Place with the right hand piston 27. The pistons 27 are held upwardly against stops 36 by springs 37 when the starting device is not in operation in which position a bleed passage 38 will register with the pipe 150; to permit the trapped fluid to exhaust to the atmosphere thru ports 39.

The stops 3132 are spaced apart sufficiently to permit a certain amount of lost motion to occur in either direction of travel of the rod 30 before engagement with the collar 29 takes place. In this way the valves 13 are controlled so that they can not admit steam to the cylinders 2 except for startlng purposes as described. For example, if the air pressure were present in the chamber 25,

the piston 27 would move downwardly just as soon as the valve 5 moves forwardly a sufficient distance to take the surface 35 of the collar 29 out from under the stem 28. On

" the return stroke of the rod 30 the stop 32 would not be brought into contact with the collar 29 until the lost motion were taken up and by properly proportioning the degree of lost motion to the length of the surface 34 and the distance between the stems 28 it is possible to have the valves 13 with their operating mechanisms in condition to deliver steam to the cylinders 2 only during those periods of the stroke where. the valve 5 cuts off the supply to the main ports 3 and 4.

Ive wish to state that the distributing mechanism 22 need not necessarily be operated in the manner indicated but might be associated with some other moving part in the driving mechanism of the locomotive just so long as the movements of the pistons 27 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 2 at the proper times.

In Fig. 2 the valve 5 is shown as travelling to the left and as just having cut off the main port 4. If a start had to be made in this position the necessary steam would be supplied through the forward valve 13, the menr ber 29 not yet having been moved by the stop 32 to bring the surface 34 under the stem 28 of the left hand piston valve 27. During this starting operation the valve 13 remains open until the steam pressure on the face of piston 17 builds up sufficiently to overbalance the pressure above the piston 14. It will then close and since, in the present instance, this pressure is 100 lbs. no more than 100 lbs. can be delivered to the piston 1 in starting the locomotive. Thus slippage at start is made practically impossible.

As soon as a start has been made the valve 5, since it is moving in the same direction as the piston 1 at this period of the cycle, will move the surface 34 under the piston 28 and the supply of starting steam will be cut off.

When the valve 13 at the head end is open the one at the crank end is closed as will be seen upon inspection of Fig. 2.

W e claim 1. In a locomotive, the combination of a cylinder, a piston, a valve chest, a steam pipe a main steam passage, a main valve set to give a limited maximum cutoff, a supplementary steam passage for supplying steam to start the locomotive, and means for limiting the pressure delivered through said supplementary passage to a predetermined maxi mum sutficiently low to prevent slippage in starting.

2. In a locomotive, the combination of a cylinder, a piston, a valve chest, a steam pipe, a main steam passage, 21 main valve set to give a limited maximum cut-oif, a supplementary steam passage for supplying steam to start the locomotive, means connecting said supplementary passage with said steam pipe, and means for limiting the pressure delivered through said supplementary passage to a predetermined maximum sufliciently low to prevent slippage in starting.

3. In a locomotive, the combination of a cylinder, a piston, a valve chest, a steam pipe, a main steam passage, :1 main valve set to give a limited maximum cut-oil, a supplementary steam passage for supplying steam to start the locomotive, a supplementary valve for controlling said supplementary passage, a piston for opening said supplementary valve, and means for sup lying fluid pressure to said piston to open t 1e valve, together with means which is subject to the pressure of the starting steam for closing said supplementary valve when the steam pressure passing through the supplementary passage counterbalances said opening pressure and said opening pressure being counterbalanced by a steam pressure which is sufliciently low to prevent slippage in starting.

4. In a locomotive, the combination with the usual cylinders, pistons, valve chests. steam pipes and main steam passages, of main valves set to give a limited maxin'ium cnt-ofi', supplementary steam passages for supplying steam to start the locomotive, distributing mechanism therefor, and means for limiting the pressure delivered through said supplementary passages to a predetermined maximum sufliciently low to prevent slippage in starting.

5. In a locomotive, the combination with the usual cylinders, pistons, valve chests, steam pipes and main steam passages, of main valves set to give a limited maximum cut-ofi', supplementary steam passages for supplying steam to start the locomotive, distributing mechanism therefor, and means for limiting the pressure delivered through said supplementary passages to a predetermined maximum sufficiently low to prevent slippage in starting, together with means for initiating and discontinuing at will the operation of said limiting means and of said distributing mechanism.

6. In a locomotive, the combination of a cylinder, a piston, a valve chest, a steam pipe, a main steam passage, a main valve set to give a limited maximum cut-off, a supplementary steam passage for supplying steam to start the locomotive and fluid pressure actuated means for opening said supplementary passage, said means being subject to the influence of the pressure of the starting steam whereby the supplementary passage is closed when the starting pressure reaches a predetermined maximum which is suiiiciently low to prevent slippage in starting.

7. In a locomotive, the combination of a cylinder, a piston, a valve chest, asteam pipe, a main steam passage, a main valve set to give a limited maximum cut-ofi, a supplementary steam passage for supplying steam to start the locomotive, and means actuated by the pressure of the steam passing through the starting passage for closing said passage when the pressure passin therethrough rises above the point where s ippage will occur.

8. In a locomotive, the combination with the usual cylinders, pistons, valve chests, steam pipes and main steam passages, of main valves set to give a limited maximum cut-0H, supplementary steam passages for supplying steam to start the locomotive, distributing mechanism therefor, and means actuated by the pressure of the steam passing through the starting passages for closing said passages when the pressure passing therethrough rises above the point where slippage will occur.

9. In a locomotive, the combination with the usual cylinders, pistons, valve chests, steam pipes and main steam passages, of main valves set to give a limited maximum cut-ofl", supplementary steam passages for supplying steam to start the locomotive, distributing mechanism therefor, and means actuated by the pressure of the steam passing through the starting passages for closing said passages when the pressure passing therethrough rises above the point where slippage will occur together with means for initiating and discontinuing at will the operation of said distributin g mechanism.

In testimony whereof, we have hereunto signed our names.

HUBERT J. TITUS. JOHN S. WALLIS.

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