US1246946A - Drifting-valve. - Google Patents

Description

W. J. SCHLACKS.

DRIFTING VALVE.

APPLICATION FILED SEPT-28,1914.

1 ,2%6,946. Patented Nov. 20, 1917.

3 SHEETS-SHEET I.

warren STATES PATENT OFFICE WILLIAM J'. SCHLACKS, OF CHICAGO, ILLINOIS, ASSIGNOR '10 MOCOIR'D AND COMIANY, OF CHICAGO, ILLINOIS, A CORPORATIQN OF NEW JERSEY.

' DBIFTING-VALVE.

I Specification of Letters Patent.

Patented Nov. 20, 1917.

Application filed September 28, 1914. Serial No. 863,954.

To all whom it may concern:

Be it known that I, WILLIAM J. SCHLAOKS, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Drifting-Valves; and I do hereby declare the following'to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention has for its object to provide an improved drift valve for locomotives, and to such ends, generally stated, the invention consists ofthe novel devices and combinations of devices hereinafter described and defined in the claims.

The well known purpose of a drift valve is to open up an auxiliary or by-passage between the locomotive boiler and the cylinders, to thereby afford a limited supply of saturated steam to the cylinders when the normal steam supply through the throttle valve is cut off and the engine is running under momentum. Several types of drift valves have hitherto been proposed, and some of these have been efficient to a limited extent, but all have been subject to serious objections, and none, so far as I am aware, have satisfactorily solved the problem.

The advent of the superheater locomotive, furthermore, has made imperative the de mand for such an automatic drift valve. It is found that in the superheater locomotives, the main valve and cylinder packing rings and bushings, for instance, do not last nearly as long as in saturated steam engines. The reason for this is that the superheated steam is at higher temperature than the flashing point of lubricating oil, so that when the throttle is closed before the engine stops, or when the engine is allowed to drift any considerable distance with the throttle valve closed, the oil that was lubricating the valves and c linders when the throttle was opened, will then very quickly burn, because the oil, at such times, is immediately'surrounded by an atmosphere that supports the combustion of oil. This oil is, therefore,

quickly consumed, due to the hot cylinder 'walls, resulting from the high temperature for the oil, and hence, when the engine is drifting with the tlirottle shutoff, there is no operative carrying medium in the customary arrangement. My invention, however, provides this carrying medium at such times. When a partial vacuum is formed by the locomotive drifting without steam in the valves or cylinders, the hot gases from the front of the boiler, in addition to the cinders, are drawn into the valves and cylinders, and such gases are sometimes compressed by the pistons to such a degree that the temperature thereof is raised as high as 1,900 degrees.

Hence, it is evident that a drift valve, to be eflicient, should not allow even a partial vacuum to be formed in the cylinders or steam chest, but should afford a supply of saturated steam, through the auxiliary passage, in time to prevent the formation of even a partial vacuum, such as will draw in the gases, air, dirt, or cinders. In several drift valves hitherto designed, the operation thereof, to admit steam through. the auxiliary passage has been dependent upon the initial formation, or partial vacuum within the cylinder of the steam chest.

My improved drift valve is automatic and never permits the formation of partial vacuum within the cylinders or steam chest, but, on the contrary, affords a supply of saturated steam through the by-passages, in a manner which maintains pressure, above that of the atmosphere, within the cylinders and steam chest, when the engine is drifting or driven with the throttle closed.

In the accompanying drawings which illustrate the improved valve, like characters indicate like parts throughout the several views. Referring to the drawings:

Figure 1 is a view in diagrammatic front elevation showing my improved drift valve applied to a locomotive of the-superheater ty e;

, ig. 2 is a section taken centrally and longitudinally through the improved drift valve, some parts being shown in full, and the parts being in their normal position; and

Fig. 3 is a view corresponding in line of section of Fig. 2, but illustrating different positions of the difi'erential piston valves.

Of the parts of the locomotive it is only desirable to particularly notethe boiler 1, the cylinders 2 and the valve chambers or steam chests 3, and saddle casting 4C.

The improved drift valve is applied in a by-passage that is independent of throttle controlled supply of steam, and which connects the boller to the valve chamber or steam chest, preferably, through the delivery portion of the superheated steam supply channel.

The drift valve proper comprises three main elements, to-wit, a differential cylinder or valve casing, a main difierential piston valve, and a sup lemental differential piston. The difierential cylinder or casing 5 has internal cylindrical surfaces 6, 7 and 8. The cylindrical surface 6 is but sli htly larger in diameter than the cylindrica surface 7 but the cylindrical surface 8 is very small, as compared with the surfaces 6 and 7. The casing, in which the cylinder 8 is formed, is shown as connected to the main casing by a conical slot head 5 which leaves that end of the casing 5 open to the atmosphere.

The casing 5 is provided with a port 9 that is connected to the boiler, by a pipe 10. Also, the casing 5 is provided with orts 11 and 12, that are separated by a ridg 13, but are both connected by a pipe 14, to the superheated steam channel 15,-

which latter is of the usual well known construction, and leads from the superheater to the valve chamber or chest 3. The head end of the casing 5 has a; port 16 that is connected by a pipe 17 to the locomotive exhaust chamber or channel 18.

The main differential piston comprises a hollow stem 19 having internal shoulders at and l and piston heads 20, 21, 22 and 23. The piston heads 20 and 21' are of the same diameter and engage the cylindrical surface 6; the piston head 22 is of such less diameter than the piston heads 20 and 21 that it properly engages the cylindrical surface 7 and the piston head 23, which is relatively very small, works within the cylindrical surface 8. The axial-bore 2 5 of the stem 19, it will be noted, extends completely through the piston head The annular stop nut 24. is screwed onto that end of the stem 19 to which the piston head 20 is applied, and the bore 25 of the said Stem, at

nae-sees its end, is expanded to afiord a cylin4 drical piston chamber 25 that is provided with a port 26 that opens through one side of the said stem and into chamber A. which is formed between the piston heads 20 and 21. The space between piston heads 21 and 22 is treated as chamber B. The space 1n cylinder 8, at the left of the piston 23 is hereln designated as chamber 0, while the space within the cylindrical surface 25 is desi nated as chamber D.

T e supplemental difierential piston comprises a stem 27 having a larger piston head 28 and a small piston head 29.. The stem 27 Works through the stop nut or gland 24, the plston head 28 is of the same diameter as the piston heads 20 and 21, and engages the cylindrical surface 6, while the small piston head 29 works within the chamber D and in close engagement with the cylindrical surface 25.

The numeral 30 indicates an air vent which, as shown, is formed ina ring 30 that is clamped between sections of the cylindrical surface 6 andprojects into the cylinder so that it affords a stop limiting the movement of the main difierential piston toward the right, and limits the movement of the supplemental difl'erential piston toward the left, in respect to Figs. 2 and 3.

Preferably, there are several of these air vents 30, and the inner end extremities thereof are, as shown, open both through the sides and under surfaces of the ring 30, so that the said air vents can never be closed by the pistons 20 and 28.

When the engine is originally fired up from a cold state, the saturated steam from the boiler enters chamber A through port 9, then from chamber A. enters chamber D through port 26, and furthermore, this saturated steam pressure passes through the axial bore 25 into chamber C. Here it is important to note that the pressure acting on the pistons 29 and 23 tending to move "the main and supplemental diflerential pistons to the right is greater than the opposing pressure acting on shoulders at and y. The pressure in chamber A on piston heads 20 and 21, is counterpoised, but the effect of pressure in chamber D on piston head 29 is to hold the latter against nut 24:, and the piston head 28 separated from piston head 20. This pressure will also tend to move the main differential piston to the right, because the shoulder on the piston 29 contacts with the stop nut 24. Hence, both the main and supplemental difi'erential pistons are moved toward the right, as shown in Fig. 2.

We will now assume that the steam pressure' in the boiler of the engine has been raised to an extent suflicient to move the engine. The throttle valve being then opened, superheated steam pressure from .the main steam channel enters chamber B,

through ports 11 and 12, and bears against the plstons 21 and 22. The greater total pressure on piston 21 over that on piston 22, due to the greater diameter 01 the said piston 21. assisted by the pressure against piston 23, results in holding the main diflerential pistons 20, 21, 22, and 23 to the right, as shown in Fig. 2, with piston 20 against the ring 30.

As already noted, the port 16, and hence the space between the piston 28 and adchamber D acting on piston 29. Hence,

when the locomotive is propelled by its own steam, the main differential pistons 20, 21, 22 and 23 will be in a position shown in Fig. 2, with pistons 28 and 29 as shown in Fig. 3, with the left side of piston 28 against the ring 30 and piston 29 near the left head of chamber D.

It should be noted that the area of piston 28 is so much greater than piston 29 that the very small pressure per square inch on piston 28 will total more than the total pressure on piston 29, from which follows that the small pressure due to the wire-drawn exhaust,-will cause piston 28 to move to the left and stay against vented collar stop 30 until the wire-drawn pressure of the exhaust has been reduced to a minimum. This insures the drift valve bein operative down to a very low piston spee of the locomotive and tends to reduce wear of piston 28 in the cylinder, because it usually will make only one movement to the left, up against vented collar stop 30, when the locomotive.

starts by steam from the throttle, and will remain in this one position stationary until the engine is almost stock still.

When the throttle valve is shut off, the locomotive runs by its own momentum, assisted by the superheated steam left in the conduits between the throttle and the cylinders, and as this steam is used, the pressure in chamber B will be gradually reduced to a predetermined pressure, say six pounds per square inch. When this reduction 1n pressure in chamber B takes place, the pressure on shoulder a", whlch 1s now the effective pressure tending to move the main differential piston to the left becomes sufficient to move such main differential piston toward the left until the piston 21 occupies a position on bridge 13 between ports 11 and 12, in which position saturated steam cham-- her A is connected to port 12, thus allowin the saturated steam pressure from the boiler, through chamber A, to flow through port 12 and pipe 14, into the steam channel, and from'thence, to the valve chamber of the locomotive and through port 11.to chamber B. The above noted position of the valve is illustrated in Fig. 3.

The movement of the main differential piston to this position is permitted because the iston 28 was previously moved to the left By the exhaust pressure when the engine was first started. The pressure on piston 29, therefore, now has no effect in tending to hold the main differential piston to the right, as the shoulder on piston 29 is out of contact with the stop nut 24:. The pressures on piston C and shoulder 3 substantially balance each other, and hence, the pressure on shoulder as will be the effective pressure for moving the main differential piston to the left.

Let it now be assumed that the engine is running Without the steam supply through the throttle, at fifty miles an hour. As the speed is reduced, the pressure in chamber B, supplied through ports 11 and 12, will be progressively increased, due to the more constant flow of saturated steam to the main steam channel, from chamber A through port 12 and pipe 14; and when this increasing pressure in the said chamber B reaches a pressure in excess of some predetermined amount, already assumed to be six pounds, the resulting pressure, due to the greater area of the piston 21 over piston 22, will overcome the comparatively constant resistance of the saturated steam in chamber D, acting on shoulder at. This will cause the main differential piston to move toward the right with the result that piston 20 will be moved against the ring 30 and piston 21 moves to the right over port 12,.thereby temporarily cutting off the supply of saturated steam through the by-passage which is controlled by the drift valve. The pistons of the drift valve will remain in the position just above noted, and the supply of saturated steam through the by-passage to the valve chambers cut oil, until the steam pressure in chamber B has been reduced to lso take place when the throttle valve is su denly opened, without the engine having stopped after the throttle was shut off, and they will be repeated as long as the 6 engine is running. When the engine is stopped, there will be no pressure on piston 28 through port 16, and the saturated steam in, chambers G and D will cause the difien ential pistons to return to normal positions 10 indicated in Fig. 2.

It will be understood that .to make the valve mechanism operative, as above described, when the engine is running, and dormant or inoperative when the engine is standing still, I depend on the wire-drawing pressure of the exhaust, due to what steam there is in the cylinders, assisted by the piston acting as a compressor, and this wire-drawing pressure, acting against the piston 28. When the locomotive is stopped, or very soon after, the w1re-drawing pressure of the exhaust is reduced to atmospheric pressure, and the more or less constant saturated steam pressure from the boiler acts in chamber C on piston 23, and in chamber D on piston 29, to return the difi'erential pistons and pistons 28 and 29 to normal ositions shown in Fig. 2.

The a ove described automatically controlled movements of the main difierential piston, whereby the piston 21 is moved back and forth between the positions indicated in Figs. 2 and 3, maintain the desired supply of saturated steam to the valves and cylinders when drifting at fifty miles an hour, or some such high speed, and at the same time, limits and regulates this supply of saturated steam, so that when the engine is running at, say eight or ten miles an hour, the said pressure cannot build up to a point beyond the control of the engineer. Otherwise stated, the arrangement described does not allow an accumulation in the main valves or steam chests of the locomotive, of a -15 pressure exceeding a predetermined amount not sufficient to cause the engineer to lose control of the locomotive.

In the difierential cylinder between the pistons 21 and 22, and preferably at the top of said cylinder I provide a relief valve 31 of the check-valve type. This relief valve, as shown, is ravity-held, normally open,.so that it afior s an escape for the saturated steam pressure from the boiler which may leak past the piston 21. If this relief from the leakage of saturated steam into the chamber B was not provided, there would be a great danger that such leakage, when the engine is allowed to stand with the cylinder cocks closed, might build up a sufiiwill cient pressure to start the locomotive. With the said normally open relief valve, this is made impossible.

The aid relief valve is, however, so araaeaeae ranged and adjusted that low pressure of, sa about one-half pound per square inch, Wlll close it, and hence, the said escape valve will always be closed when the engine is runnin and will never be closed when the engine is standing still. Obviously, the pressure 1n chamber B, when the engine is runnmg, will always be more than one-half pound per square inch, and the gradual leakage which may take place from chamber'A, past iston 21 into chamber B, will never be suficlently rapid to accumulate a pressure, anywhere nearly approaching the said assunfied pressure of one-half pound per square mc The relief ports 30, already noted, not only afiord relief from the wire-drawn exhaust leakage past piston 28, but also afiord relief for the saturated steam pressure which may leak past piston 20.

What I claim is:

1. A drift valve for locomotives having a movable element and means subject to the exhaust pressure from the locomotive and controlling the movement of said' element, whereby the exhaust pressure is utilized as a factor in the control of said drift valve.

. 2. A drift valve for locomotives comprislng a caslng having an inlet adapted to be connected with the locomotive boiler and an outlet adapted to be connected with the locomot1ve superheater, valve mechanism in said casing for normally closing communication between said inlet and outlet but adapted to be moved to establish communication therebetween, movable means to control the movement of said valve mechanism, and means subject to the exhaust from the locomotive and controlling the movement of said lastnamed means to render the valve mechanism operative and inoperative.

3. A drift valve for locomotives comprising a cylinder and a piston working therein to control the supply of steam through said cylinder, the said cylinder having an opening adapted to be connected to the locomotive exhaust passage whereby the exhaust pressure is utilized as a factor for controlling movements of said piston.

4:. A drift valve for locomotives comprising a casing and a difierential piston working therein, said casing havingan inlet and an outlet whereby it may be connected in a by-passage between the locomotive boiler and the locomotive valve chamber, said piston being adapted to normally close communication between said inlet and outlet and said casing having an opening adapted to be connected to the exhaust passage of the locomotive, and means adapted when actuated by the exhaust pressure of the locomotive to permit said piston to establish communication between said inlet and outlet.

- 5. A drift valve for locomotives compris ing a differential cylinder and a diiferential piston working therein, said cylinder havmg three openings one adapted to'be connected to the boiler, one to the exhaust and another to the normal .steam delivery channel beyond the throttle valve,-said openings being so arranged that the live steam and exhaust pressures coact on said differential piston to control. the supply of saturated steam from the boiler to the locomotive valves when the engine is drifting.

6. A drift valve for locomotives comprising a cylinder and main and supplemental difi'erential pistons working therein, said main piston having a small cylinder in which the smaller head of said supplemental piston works, means whereby said smaller head of the supplemental piston may be constantly subject to boiler pressure, the said cylinder havin three openings one adapted to be connects to the boiler, one to the exhaust and another to the normal steam delivery channel beyond the throttle valve whereby the, steam and exhaust pressures may coact on said pistons to control the supply of saturated steam to the locomotive valves when the engine is drifting.

7. A drift valve for locomotives of the superheater type comprising a differential cylinder and a differential piston working therein, said cylinder having three openings one adapted to be connected to the boiler,

one to the exhaust and another to the superheated steam channel of the locomotive whereby the boiler, the exhaust and thesuperheated steam "pressures may coact on the differential piston, to control the supply of saturated steam to the locomotive valves when the engine is drifting. t

8. A drift valve for locomotives of the superheater type comprising a cylinder and main and supplemental differential pistons working therein, said main piston having a small cylinder in which the smaller head of said supplemental piston works, means whereby said smaller head of the supplemental piston may be constantly subject to boiler pressure and said cylinder having three openings one adapted to be connected to the boiler, one to the exhaust and another to the superheater steam channel of the locomotive whereby the boiler, exhaust and superheated steam pressures may coact on said pistons to control the supply of saturated steam to the locomotive valves when the engine is drifting.

9. A drift valve comprising a differential cylinder and main and supplemental. difi'erential pistons working therein, said main differential piston having a cylinder in which one of the piston heads of said supplemental difl'erential piston is arranged to I work.

I nected to the exhaust and havin adapted to be connected to t ing a port adapted to be connected to'the' boller and another port adapted to be contwo ports e normal steam delivery channel beyond the throttle valve of the locomotive, and the said dif ferential piston having a head that is movable to and from a position between the latter two noted ports and serving when in such position to establish communication betweenthe portfor the boiler and one of'the two ports for the steam delivery channel.

'12. A drift valve for locomotives of the superheater type comprising a casing having' an inlet pipe and an outletpipe forming aby-passage adapted to be interposed between the locomotive boiler channel and the superheater steam channel, said casingalso havmg'a port adapted to be connected to the exhaust o the locomotive.

13. A drift valve for locomotives of the superheater type comprising a differential cylinder and a differential piston working therein, said cylinder having twoports adapted to be connected res ectively to the boiler and to the exhaust o the locomotive and havin longitudinally spaced ports adapted to e connected to the superheater steam channel, and the said differential piston having a head adapted to be subjected to the exhaust pressure and having another head that normally cuts off communication between the port for the boiler and both of said longitudinally spaced ports, but movable to a position between the same whereby the boiler pressure, the superheater steam pressure and the exhaust pressure are 'rendered effective on said differential piston to control movements thereof.

14. A drift valve for locomotives comprising a differential cylinder, a main differential piston, and a supplemental differential piston, said cylinder having three cylindrical surfaces of different diameters, the larger cylindrical surface thereof having at one end a port adapted to be connected to the locomotive exhaust and having in its sides longitudinally spaced ports, one adapted to be connected to the locomotive boiler and two adapted to be connected to the normal steam delivery channel beyond the throttle valve, the said main differential piston havin two piston heads engaging the larger cy mdrical surface and'two other piston heads engaging respectively the intermediate and smaller cylindrical surfaces of said differential cylinder, one of said larger piston heads 'being movable to a point between the latter two noted ports, said main difierential valve having a hollow \stem leading to a cylindrical chamber provided with a port opening outward between the two large heads of said piston, and the sald supplemental piston havmga large head engagm cylin er and provided working in the cylindrical within said main piston..

15. A drift valve for locomotives compr sing a differential cylinder and a difierentlal piston working therein, said cylinder havin a port adapted to be connected to the boiler, another port adapted to be connected to the exhaust, and having two ports adapted to 'be connected to the normal steam delivery channel beyond a throttle valve of said locomotive, and the said difierential iston having a head that is movable to and from a position between the latter two noted orts and serving, when in such position, to establish communication between the port for the boiler and one of said two ports for the steam delivery chamlel, and a normally opened vent valve in that portion of said difierential cylinder which is adapted to receive the normal steam supply through one of the said two ports, the said vent valve arranged to be automatically closed by premure less than that which is suficient to move the locomotive.

16. A drift valve for locomotives comprising a differential cylinder, a main difierenwith a small head chamber formed tial piston and a supplemental .difierential piston, said cylinder having three cylindrical surfaces of difi'erent diameter, the larger cylindrical surface thereof having a port at one end adapted to be connected to the locomotive exhaust and having in its sides longitudinally offset ports, one'adapted to be connected to the engine boiler and two adapted to be connected to the normal steam delivery channel beyond the throttle valve, the said main difierential piston having two piston heads engaging the larger cylindrical surface, and two other piston heads engaging, respectively, the intermediate and small cylindrical surfaces of said difi'erential cylinder, one of said larger piston heads being movable to a point between the latter two noted ports, said main difi'erential valve having a hollow stem leading to a cylindrical chamber provided with a port opening outwardbetween the two large heads of said piston, the said supplemental piston having a large head engaging the large cylindrical surface of said cylinder, and provided with a small head working in the cylindrical chamber formed within said main piston, and a normally opened relief valve opening from the cylindrical surface of intermethe large cylindrical surface of said aaeaeae diate diameter, arranged bev closed by pressure from within said cylinder in excess of a predetermined pressure which is v to the exhaust, and another to the'normal I steam delivery channel beyond the throttle valve, whereby the steam and exhaust pressures may coact on said pistons to control the supply of saturated steam to the locomotive valves when the engine is drifting, and a relief port opening from said cylinder at a point that is always between adjacent heads of saidmain and supplemental difierential pistons.

- 18. A drift valve for locomotives comprising a cylinder and main and supplemental difi'erential pistons working therein, said main piston having asmall cylinder in which the smaller head of said supplemental piston works, means whereby said smaller head of the supplemental piston may be constantly subjectedto boiler pressure,.and the 19. A drift valve for locomotives comprising a difierential cylinder, a main difierential piston and a supplemental difl'erential piston, said cylmder having three cylindrical surfaces of different diameter, the larger cylindrical surface thereof having a port at one end adapted to be connected to the locomotive exhaust and having in its sides longitudinally oflset ports, one adapted to be connected to the engine boiler and two adapted to be connected to the normal steam delivery channel beyond the throttle valve, the said main differential piston havin two piston heads engaging the larger cylin rical surface, and two other piston'heads engaging, respectively, the intermediate and smaller cylindrical surfaces of said difierential cylinder, one of said larger piston heads being movable to a oint between the latter two noted ports, sai main difierential valve having a hollow stem leading to a cylindrical chamber provided with a port opening outward between the two large heads of said piston, and the said supplemental piston having a large head engaging the large cylindrical surface of said cylinder, and provided with a small head working in the cylindrical chamber formed within said main piston, and a stop flange 10 projecting into said cylinder between adjacent heads of said main and supplemental differential pistons, the said stop flange having an air vent therein.

In testimony whereof I aflix my signature in presence of two witnesses.

WILLIAM J. SCI-ILACKS. Witnesses:

C. W. RUDOLPH, DONALD D. THILERT.

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