US1970322A - Steam engine valve - Google Patents

Description

Aug. 14, 1934.

W. F. KIESEL. JR

STEAM ENGINE VALVE 2 Sheets-Sheet l Original Filed Aug, 3, 1927 Aug. 14, 1934. l w F, KIESEL, JR 1,970,322

STEAM ENGINE VALVE Original Filed. Aug. 3, 1927 2 Sheets-Sheet 2 Patented Aug. 14, 1934 l S''ETES 8 Claims. (Cil. 121-142) This invention relates to the valves for steam through the main valve showing in detail the engines and more particularly to vaives intended drive mechanism for. it and the auxiliary valve; to be used on locomotives operating at veryV high Figure 3 is a transverse vertical section on steam pressures. The present application is a vbroken line 3--3 or" Figure 2; and 5 division of my copending application Serial No. Figure e is alongitudinal section through the 60 210,412, led August 3, 1927. y auxiliary valve and the main valve taken on bro- It is a general object of the present invention ken line 4 4 of Figure 3. to provide a novel and improved valve for loco- With the use of very high pressure steam, the

motive engines together with operating gear for conventional form of valve and valve motion,-

the same. now` used on locomotives, is not satisfactory to 65 More particularly, it is an object of the invenrealize the expansion possibilities of such prestion to provide, in a locomotive, a main valve sure, and some means must be provided to achieve adapted to control the flow oi live and exhaust earlier cut-off than is now possible without exsteam to and from a cylinder, together with an cessive throttling of the steam. The convenauxiliary valve whose sole function is to control tional slide valve either of the D or piston type, 70. the cut-01T and to limit the same to a small peroperated by any form of `valve gear, such as the centageof the stroke at moderate and high Walschaert type, has the various events which Speeds. Y it controls so interconnected that a change in the A further object of the invention consists in hook-up to change, for instance, the cut-off,

2O providing means to be used in connection with causesa changein the various other events, nota- 75` auxiliary and limiting cut-ofi valves, to supply bly release and compression. Ii, with admission steam throughout substantially the full stroke occurring slightly before dead center, an attempt of the piston for starting purposes. is made to provide cut-ori early in the stroke,

One feature Aof the invention comprises a novel the angle of advance, determined by these two arrangement for actuating the auxiliary cut-OIT events, is large and causes either release or com.- 80 valve from the linkage mechanism of the main pression or both to be early. If one is improved, valve. it must'be at the expense of the other. On high A further feature of the invention comprises Speed engines,` a rather high compression is dethe arrangement of an auxiliary cut-off valve sired to absorb the kinetic energy oi the reciprocontrolling the admission of live steam into what eating parts Vat the end of the strokes, but on 85 may be termed the receiver volume of the main lower speed engines such compression is not only valve chamber. unnecessary but undesirable because it reduces Another and further object of the invention theamount of work per stroke. A locomotive is consists in the provision of novel means for byessentially a variable speed machine, and it will passing live steam around the cut-off valve to be seen that an attempt to obtain an early cut- 90 the receiver volume of the main valve chamber off at moderate speeds, as required Jio: economy, on starting, when the auxiliary cut-oit valve prowill Vincrease the compression too greatly and duces a cut-ofi too early in the stroke of the also seriously advance the release. The release piston to provide adequate power. should not be advanced materially where using Other and further features and objects of the very high pressure steam, for it materially re- 95 invention will be more apparent to those skilled duces the economy. in the art upon consideration of the accompany- The present invention contemplates overcoming drawings and foilowing specification wherein ing the above and other difficulties by the use are disclosed several exemplary embodiments of of an auxiliary or cut-off valve arranged between the invention with the understanding that such the` main valve, which may be of any desired 100 changes may be made therein as fall within the form, and the steam pipe and actuating this cutscope of the appended claims Without departing off valve from the same link motion that actuates from the spirit of the invention. the main valve. According to this invention the In said drawings: f main valve is-so arranged as to permit cut-offs Figure 1 is a side elevation of a portion ofl a varying from small amounts to a predetermined 105 locomotive disclosing a cylinder, the cylinder maximum of 80% to 90% as desired, whereas valves, some of the drivers, the connecting rod the cut-off valve is so arranged as to admit steam and the valve Voperating mechanism, or gear, up to about 10% of the piston travel when the which is of the Walschaert type; Y link block is in mid-position and up to about Figure 2 is a longitudinal vertical section 25% when the link block is in either of its exg 110 treme positions. rlhis valve controls the admission of steam into a definitely determined space, in the case shown, the main valve chamber volume surroundng the main valve barrel. The valve disclosed is of the inside admission type and the space surrounding the main barrel thereof, and into which steam is admitted by the cut-oif valve will hereinafter be designated the receiver volume. In operation, after closing of the cut-off valve, the receiver volume and the portion of the cylinder up to the piston will ybe filled with live steam which then expands and moves the piston until the main valve closes and causes cut-off. Further expansion will then occur in the cylinder volurne alone, and will continue until the main valve opens for release.

However, when starting and travellingslowly under a heavy load, it is desirable to permit a maximum cut-olf of at least 80% which the main valve will allow, but which the cutoff valve lwill not allow. Hence some means is provided to allow ley-passing or leakage of steam from the source of steam supply into the receiver volume for starting purposes, but this means is provided with a constriction so that the amount of steam flow therethrough will vproduce but little effect when running at high speeds and, therefore, the cut-off as determined by the auxiliary cut-off valve will be effective.

Referring to the drawings, there will be seen at 1G the conventional cylinder of a locomotive within which is located the piston'rlo" driving the drivers 11 through the piston rod 12, the connecting rod 13 and the pitman rods 14. The' rod 13 is journaled on crank pin 15 secured to the face of one of the drivers. The connection between the connecting rod 13 and the piston rod 12 is effected at the cross head 16 which slides in 4 the guides 1'?.

Y Steam is admitted to either endv ofthe cylinder as required and exhausted therefrom through the ports 18 controlled by the slide valve 19, recipro` cable in a valve chamber 20, and adapted to be moved in timed relation to the piston by a valve rod 2l passing through a stulingbox 22 in'one head of the chamber. The valve 19 may-oe of any of the well known and conventional types, the one shown being a piston valve to` provide inside admission and outside exhaust. It is not believed to be necessary to here describe the'operation of the valve 19 other than to say that it is so designed as to allow cut-off up to substantially 86% to 90% of the piston stroke, and can be,'.by

its'linkage, adjusted to produce cut-offs at fairly small percentages of the piston strokegsay about 20%' to 25%. Adjustments* of the linkage to thus vary the cut-off through this range has' but little effect on admission, release and compression.

Motion is imparted to the valve in timed relation to the motion of the piston by means ofthe well known Walschaert valve gear, comp-rising the eccentric rod 24 driven from the'eccentric pin 25 and serving to rock the link 26 trunnioned at 22 and provided with an arcuate slot 28 in which 65 the link block 25 secured to oneend of the radius rod is adiust'ably positioned. 'A link 31`is attached to the cross head and enables the motion of this cross head to be combined with the lmotion of the radius rodv obtained from the eccentric pin by means of the lap and lead lever 32 having its endspivoted respectively to one end of each radius rod 30 and the link 31.

At 33 the lap and lead lever 32 is pivotally con-y nected to a slider 34 operating in ways 35 in the brackets 36 extending from the stuffing-boX-end head 37 of the valve chamber 20. It will be seen that the lap and lead lever oats between the link 31 and the radius rod 30 and is supported by means of the slider 34 to which it imparts the combination of the motions of the cross head and the eccentric pin. The amount and direction of movement of the radius rod 30 may be changed by varying the position of the link block 29 in the slot 28 in the link by means of the lifting link 30 attached to the bell crank lever 38, which is operated by the reach rod 39 leading to the cab.

In Fig. 4 is shown the auxiliary, or cut-olf valve Vcomprising a hollow cylinder 40 adapted to be reciprocated within the sleeve 41 in the auxiliary valve housing 42. The valve is open at both ends in order that steam may flow through the same fromthe main steam inlet 43. It is provided with the packing rings 41 to maintain a steam tight nt with the sleeve. When the valve is moved a sufficient distance from its center position ineither direction, steam may now by the end of theV valve and through openings in the sleeve into Ythe annular passage 44 which communicatesby way of the port 44' with the central space 45 surrounding the main piston valve 19 which distributes the saine to either end of the cylinder-ina well known manner. i

Motion is imparted tothe cut-off valve in the desired relation to the motion of the main valve by means of the linkage best shown in Fig. 2. The arms 36 extending "from` the head of the main valve chamberto form guides for the slider are'bent upwardly tov form the trunnions 47 betwee'nwhich is pivoted the lever 48 whose lower endisconnected by a link 49 to an intermediate point on the lap andlead lever 32. The upper end ofthe lever`43 is connected, by a link 50, to the lower end of the arm 51, secured to the'rock shaft 52,7 best shownr in Fig. 4. This shaft passes through a gland 53 in the wall of the extension 'xr.'

54,- near the top, and at one' end, of the auxiliary valve housing. The arm Y55 is1se'cured to the inner end of the rock shaft 52. The lower end of thisarm 55 is connected, by a link 57 which passes-through the hollow Valve member 40, to

the trunnionsi58 `on the far end of that valve member. It will thus be seen that the auxiliary valvewillmo've in' unison' with the main valve, but not necessarily in exact synchronism therewith.

The rock shaft 52 together with its two arms 51 and 55 isu'sed in order to eliminate a stuffing-box and its chances for leakage when subjected to the extremely vhigh pressure steam in the auxiliaryvalve chamber. A tight fit where the rock shaft passes through the gland 53 is obtained 1;A

by means of? a collar secured to the rock shaft and having a ground fit with the inner surface of the gland against which it is maintained by steam pressure in a well known manner.

`The operation of the'parts of the structure so far described,"will be'readily understood. It will be seenthat the cut-off valve controls absolutely the flow ofs'team into the space 45 surrounding the main valve, which space has been termed the receivervolume and which has less than j,

. main valve.

Lamaze and thence into the cylinder until cut-off is effected by the auxiliary valve, after which steam, both in the cylinder and in the receiver volume, will expand until cut-oir is effected by the main valve 19, after which further expansion will take place in the cylinder only, until release is effected by the main valve.

The main Valve, as before stated, may have a maximum cut-ofi of from to 90% when the link block is at a maximum distance from the trunnions in either direction, and will preferably have a minimum cut-oit, when fully hooked up, substantially equal to the maximum cut-off of the auxiliary valve, ie., about 25%.` The main valve thus has a variation between these limits rather than between the wider limits ordinarily necessary for economical operation. The corelated events controlled by the main valve can thus be better adjusted and proportioned, and furthermore less throttlingoi thesteam takes place during admission'. v

The auxiliary valve is designed to provide cutol's varying from substantially 10% to 25% of the piston stroke in accordance with the position of the link block. The percentage of cut-off varies with movement of the link block in the link in the same manner as does that of the With this arrangement, it will be seen that while the port opening afforded by the cut-off valve is large and provides a satisfactory flow of steam at the smaller cut-offs without undue throttling, this valve, nevertheless, linnts the cut-oit to a maximum of about 25% when the linkage is in extreme position and can reduce the same to a minimum of substantially 10% when the linkage is fully hooked up, but maximum cut-off of around 80% Acannot be obtained for starting purposes. It is essential that a cut-on" of such proportions be available for starting under heavy Vloads and on steep grades.

Steam for cut-oiis up to substantially 80%, or the maximum allowed by the main valve design and setting may be provided by a bleeder, or

:port S2, in the wall of the auxiliary valve 40,

as shown in Fig. e. This port is positioned in such a manner, in relation to the passage 44, that it is always in communication with this passage when the passage is covered by the i valve.

This bleeder is oi such size as to provide sufiicient steam to the receiver after closure of the cut-off valve', for cut-offs up to the maximum allowed by the main valve when starting j and when the locomotive is moving at very slow speeds. However, the port is so restricted that at speeds of above 10 miles an hour the amount of steam iiowing through the bleeder is inconsequential, due to the short time occupied by each stroke, and has almost no effect on the steam distribution which is then wholly determined by the auxiliary valve, whereas at starting and at very low speeds, the cut-off is wholly determined by the main valve.

The advantages of the construction above described will be readily appreciated by those skilled in the art. It will be seen that all of the advantages are obtained with but slight additions to the usual mechanism. The apparatus necessary for controlling the auxiliary or cutoff valve is extremely simple and comprises but three parts, The separate cut-off valve enables a high pressure locomotive or, in fact, any steam engine oi variable speed to be operated more economically and with better main valve functioning. It allows an earlier cut-off than is possible with a. conventional form of single valve controlled by the usual linkage and provides for quicker opening and closing of the ports without deleterious effects on the conjugate `functions of the main valve. The provision o a f receiver volume of abo-ut one-third of the cylinder capacity allows for a better use of the full expansion possibilities of the very high pressure steam. Theadvantages of late cut-off for starting are obtained in a simple manner without adding to the necessary manual controls inthe cab.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is: i

1. In a steam locomotive, in combination, a cylinder, a piston reciprocable therein, a slide valve controlling live and exhaust steam for said cylinderand a separate cut-o valve between said slide valve and the source of live steam, said cutoi valvebeing arranged to provide maximum cutoff less' than that required for starting, and provided by the main valve and means in said cutoil valve having a constant admission area to admit suiiicient steam to said slide valve up to the required piston displacement for operation at slow speeds only.

2. In a steam locomotive, in combination, a cylinder, a piston reciprooable therein, a main valve adapted to control admission and to provide the maximum cut-off ever required, a cut-od valve between the source of steam and the main valve arranged to provide as its maximum cut-off that required at normal operating speeds, and means in said cut-off valve having a constant admission area to admit sufficient steam to said main valve for startingpurposes only during the period from cut-oit by the cut-01T valve to cut-off by the main valve.

3. In a steam locomotive, in combination, a cylinder, a piston reciprocable therein, a main valve adapted to control admission and to provide the maximum cut-off ever required, a cut-off valve between the source of steam and the main valve arranged to provide as its maximum cut-ofi that required at normal operating speeds, and means including a port of such size in said cut-0E valve as to be eiective at low speeds only to admit steam to the main valve for starting purposes during the period from cut-orf by the cut-oit valve to cut-off by the main valve.

4. In a locomotive, in combination, a pair of cylinders, pistons therein adapted to operate with cranks displaced at a xed angle, a main valve chamber for each cylinder, a valve in each main valve chamber, a cut-off valve chamber adjacent each main valve chamber, a cut-ofi valve therein adapted to control the flow of steam to said main valve chamber and adapted to always give early cut-off and means in said valve of iixed iiow area to pass a small quantity of steam to the main valve chamber after cut-off by the cut-01T valve to admit suflicient steam for operating at low speeds until cut-oli by the main valve.

5. In a locomotive, in combination, a cylinder, a piston operative therein, a main valve arranged to cut-01T in full gear after the piston has completed at least two-thirds of its stroke, a cut-off valve arranged to cut-od steam to the main valve before the piston has completed one-third of its stroke, a steam space between the cut-off valve and the main valve, and means independent of the position of the cut-oit valve after cut-off to admit a limited quantity of steam through said out-off valve to said space after ncut-oi by said cut-off valve. t

6. In a locomotive, in'cornbination,` a cylinder, a piston operative therein, a main kValve chamber, a valve operative therein, a cut-off valve chamber adapted to be supplied with live steam, a passage between a port intermediate the ends of said cutoiT Valve chamber and a port in the main Valve chamber, a hollow open-ended valve member in said cut-off valve chamber normally covering said port therein, means to reciprocate said valve in unison with said main valve to uncover Vsaid port and a bleeder in said out-oi valve always open to a iixed area to said port when the port is covered by the valve. l f Y '7. In a locomotive, in combination, `a cylinder, a piston operative therein, a main valve chamber, a valve operative therein to provide late outoi, a out-ofi" valve chamber adapted to be supplied with live steam,a port through a wall of said chamber connected by a passage to. said main valve chamber, a valve member inv said chamber to cooperate with said port to control the normal flow of steam to said main valve to always provideearly cut-off and a bleeder passage through said'valve to always register with said port with constant area when said port is covered by said valve, said passage having such steam capacity as to provide sufficient steam to operate the locomotive with main valve cuteoff at low speeds but with substantially cut-off valve cutof at high speeds. Y

8. In a'steam locomotive, in combination, a cylinder, a piston reeiprocable therein, a connecting rod and crank, a main valve adapted to control admission and adjustable to vary cut-off and receiving a component of its motion from said crank, a cut-01T valve controlling a port between the source vof steam and the main valve arranged to provide as its maximum cut-off that required at normal operating speeds and obtaining its movement from the drive for the main valve, and a passage oi xed admission area from the cutoff valve chamber to the main valve chamberso disposed that when the cut-off Valve covers said port said passage provides for a constant measured flow of steam to the main valve chamber.

WILLIAM F. KIESEL, J R.

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