US1970323A - Steam engine valve - Google Patents

Description

INVENTOR.

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M Z ATTORNEYS.

Aug. 14, 1934.-

W. F. KIESEL, JR

STEAM ENGINE VALVE 2 Sheets-Sheet 1 Original Filed Aug. 3. 1927 & BY

2 Sheets-Sheet 2 w, F. KIESEL, JR

' STEAM ENGINE VALVE Original Filed Aug. 3, 192'? Aug. 14, 1934.

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Patented Aug. 14-, 1934 r.

wire s'r'rss jars STEAM ENGINE VALVE 7 William F. Kiesel, Jr., Hollidaysburg, Pa. Original application August 3, 1927, Serial No. 210,412. Divided and this application June 3, 1929, Serial No; 368,012 l 12 Claims. (Cl. 121142) This invention relates to the valves for steam through the main valve showing in detail the engines and more particularly to valves intended drive mechanism for it and the auxiliary valve; to be used on locomotives operating at very high Figure 3 is a longitudinal section through the steam pressures. The present application is a cut-off valve and the main valve showing a bydivision of my copending application Serial No. pass control;

210,412, filed August 3, 1927. V Figure 4 is an enlarged View in vertical see- It is a general object of the present invention tion of the automatic by-pass valve shown in to provide a novel and improved valve for 1000- Figure 3; and motive engines together with operating gear for Figure 5 is a view similar to Figure 4, but

s the same. showing a by-pass valve having pneumatic con- 65 More particularly, it is an object of the inventrol. tion to provide, in a locomotive, a main valve With the use of very high pressure steam, the adapted to control the flow of live and exhaust conventional form of valve and valve motion, steam to and from a cylinder, together with an now used on locomotives, is not satisfactory to auxiliary valve whose sole function is to control realize the expansion possibilities of such pres- 0 the cut-off and to limit the same to a small persure, and some means must be provided to centage of the stroke at moderate and high achieve earlier cut-off than is now possible withspeeds. out excessive throttling of the steam. The con- A further object of the invention consists in ventional slide valve either of the D or piston providing means to be used in connection with type, operated by any form of valve gear, such 7 auxiliary and limiting cut-off valves, to supply as the Walschaert type, has the various events steam throughout substantially the full stroke which it controls so interconnected that a change of the piston for starting purposes. in the hook-up to change, for instance, the out- One feature of'the invention comprises a novel off, causes a change in the various other events,

arrangement for actuating the auxiliary cut-oii notably release and compression. If, with advalve from the linkage mechanism of the main mission occurring slightly before dead center, an valve. 1 attempt is made to provide cut-oii early in the A further feature of the invention comprises stroke, the angle of advance, determined by these the arrangement of an auxiliary cut-off valve two events, is large and causes either release or 30 controlling the admission of live steam into what compression or both to be early. If one is im- 5 may be termed the receiver volume of the main proved, it must be at the expense of the other. valve chamber. On high speed engines, a rather high compres- Another and further object of the invention sion is desired to absorb the kinetic energy of consists in the provision of novel means for bythe reciprocating parts at the end of the strokes,

- passing live steam around the cut-off valve to but on lower speed engines such compression m 0 the receiver volume of the main valve chamber not only unnecessary but undesirable because it on starting, when the auxiliary cut-01f valve proreduces the amount of work per stroke. A locoduces a cut-off too early in the stroke of the motive is essentially a variable speed machine, piston to provide adequate power. and it will be seen that an attempt to obtain an 40 Other and further features and objects of the early cut-off at moderate speeds, as required for 95 invention will be more apparent to those skilled economy, will increase the compression too greatin the art upon consideration of the accompanyly and also seriously advance the release. The ing drawings and following specification wherein release should not be advanced materially where are disclosed several exemplary embodiments of using very high pressure steam, for it materially the invention with the understanding that such reduces the economy. '100 changes may be made therein as fall within the The present invention contemplates overcomscope of the appended claims without departing ing the above and other difficulties by the use of from the spirit of the invention. an auxiliary or cut-off valve arranged between In said drawings: the main valve, which may be of any desired Figure 1 is a side elevation of a portion of a form, and the steam pipe and actuating this cut- 105 locomotive disclosing a cylinder, the cylinder off valve from the same link motion that actuates valves, some of the drivers, the connecting rod the main valve. According to this invention the and the valve operating mechanism, or gear, main valve is so arranged as to permit cut-offs which is of the Walschaert type; varying from small amounts to a predetermined Figure 2 is a longitudinal vertical section maximum of to a es Whereas the cut-off valve is so arranged as to admit steam up to about 10% of the piston travel when the link block is in mid-position and up to about 25% when the link block is in either of its extreme positions. This valve controls the admission of steam into a definitely determined space, in the case shown, the volume between the main valve and its barrel and the volume between the auxiliary valve and its barrel. The main 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-off 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 be filled with live steam which then expands and moves the piston until the main valve closes causes cut-ofi. Further expansion will then occur in the cylinder volume alone, and will continue until the main valve opens for release.

However, when starting and travelling slowly under a heavy load, it is desirable to permit a maximum cut-off of at least which the main vaive will allow, but which the cut-off valve will not allow. Hence some. means is provided to allow by-passing or l akage 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 produce but little elfect when running at high speeds and, therefore, the cut ofi" as determined by the auxiliary cut-oi? valve will be effective.

Referring to the drawings, there will be seen at 19 the conventional cylinder of a locomotive within which is located the piston 10 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 pistonrod 2 is effected. at the cross head 16 which slides in the guides 17.

Steam is admitted to either end of the cylinder as required and exhausted therefrom through the ports 18 controlled by the slide valve 19, re-

ciprooable in a valve chamber 20, and adapted .to be moved in timed relation to the piston by a valve rod 21 passing through a stuffing box 22 in one head of the chamber. The valve 19 may be 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 80% to90% of the piston stroke, and can be, by its linkage, adjusted to produce cutofis at fairly small percentages of the piston stroke, say 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 timedrelation to the motion of the piston by means of the well known Walschaert valve gear, comprising the eccentric rod 24 driven from the eccentric pin 25 ,and serving to rock the link 26 trunnioned at 27 and provided with an arcuate slot 28 in which the link block secured to one end of the radius rod 30 .is adjustably positioned. A link 31 is attached to the cross head and enables the motion of this cross head to be combined with the motion of the radius rod obtained from the eccentric pin by .the lap and lead lever 32.

far described will be readily understood.

means of the lap and lead lever 32 having its ends pivoted respectively to one end of each radius rod 30 and the link 31. At 33, the lap and lead lever 32 is pivotally connected to a slider 34 operating in ways 35 in the brackets 36 extending from the stufiing-box-end head 37 of the valve chamber 20. It will be seen that the lap and lead lever floats 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. 3 is shown the auxiliary, or cut-off valve comprising 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 from the main steam inlet 43. It is provided with the packing rings 41 to maintain a steam tight fit with the sleeve. When the valve is moved a sufficient distance from its center position, in either direction, steam may flow by the end of the valve and through openings in the sleeve into the annular passage 44 which communicates by way of the port 44' with the central space 45 surrounding the main piston-valve 19 which distributes the same to either end of the cylinder in a well known manner.

Motion is imparted to the 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 chamber to form guides for the slider are bent upwardly to form the trunnions 47 between which is pivoted the lever 48 whose lower end is connected by a link 49 to an intermediatepoint on The upper end of the lever 48 is connected, by a link 50, to the lower end of the arm 51, secured to the rock shaft 52, best shown in Fig. 3. gland 53 in the wall of the extension 54, near the top, and at one end, of the'auxiliary valve housing. The arm 55 is secured to the inner end of the rock shaft 52. The lower end of this arm 55 connected, by a link 5'7 which passes through the hollow valve member 40, to the trunnions 58 on the far end of that valve member. It will thus be seen that the auxiliary valve will move in unison with the main valve, but not necessarily in exact This shaft passes through a synchronism therewith. The rock shaft 52 together with its two arms 51 and 55 is used in order to eliminate a stufiing-box and its chances for leakagewhen subjected to the extremely high pressure steam in the auxiliary valve chamber. A tight fit where the rock shaft passes through the gland 53 is obtained 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 It will be seen that the cut-off valve controls absolutely the flow of steam into the space 45 surrounding the main valve, which space has been termed the 1 valve will govern only the cut-01f. Upon admission by the main valve, steam expands from the receiver volume and flows into the cylinder followed immediately by a flow of steam directly from the steam pipe through the cut-off valve and the passage a4 into the space 45 and thence into the cylinder until cut-on is efiected by the auxiliary valve, after which steam, both in the cylinder and in the receiver volume, will expand until cutoir 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-off of from 80% to 90% when the link block is at a maximum distance fromthe trunnions in either direction, and will preferably have a minimum cut-off, when fully hookedv up, substantially equal to the maximum cut-off of the auxiliary valve, i. e., about 25%. The main valve thushas a variation between these limits rather than between the wider limits ordinarily necessary for economical operation. The co-related events controlled by the main valve can thus be better adjusted and proportioned, and furthermore less throttling of the steam takes place during admission.

- The auxiliary valve is designed to provide cutoifs 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 main valve. With this arrangement, it will be seen that while the port opening afforded by the cut-oil valve is large and provides a satisfactory flow of steam at the smaller cut-offs without undue throttling, this valve, nevertheless, limits the cut-off to a maximum of about 25% when the linkage is in extreme position and can reduce thesame to a minimum or" substantially 10% when the linkage is fully hooked up, but maximum cut-off of around 80% cannot be obtained for starting purposes. It is essential that a cut-off of such proportions be available for starting under heav loads and on steep grades.

Steam for cut-oil's up to substantially 80%, or the maximum allowed by the main valve design and setting may be provided by a suitable by-pass passage around the cut-off valve such as shown at in Figs. 3, 4 and 5. h

This by-pass passage is of such size as to provide suilicient 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 and when the locomotive is moving at very slow speeds. However, the passage is so restricted that at speeds of above 10 miles an hour the amount of steam flowing through the passage is inconsequential, due to the short time occupied by each stroke, andhas almost no offeot on the steam distribution which is then wholly determined by the auxiliary valve, whereas at starting and at very low speeds, the cutoff is wholly determined by the main valve.

As shown in Fig. 3, the pipe 65 extends from the steam pipe 43 to the receiver volume 45 and has sufficient area to permit the required amount of steam to flow therethrough for starting purposes after cut-oif by the cut-cit valve. An automatic valve 66 is provided between this pipe 55 and the steam pipe 43 and is best shown in Fig. i. It includes within the casing two communicating, concentric, cylindrical bores 67 and 68 in which fit, respectively, the pistons 69 and '70, either integral, or suitably secured together and each provided with packing rings. The bottom of the bore 67 is closed by the head 71 through which passes the pipe 65. The head 72, preferably formed integral with the casing, closes the opposite end of the bore 68 which, however, is vented to the atmosphere at 72. The flange 73 on the side of thecasing is adapted to be secured against the flat end 74 of the auxiliary valve housing 42, so that steam may pass through the opening '76 in the steam pipe and through the port 77 into the ring-like chamber 78 around the piston 69 near its junction with the smaller piston.

.A beveled seat 79 between the two cylindrical bores in the housing is engaged by a suitable bevel .on the upper end of the larger piston to prevent steam flowing through the port '7'? from passing beyond the space 78, under running conditions, and into the space 80, at the junction of the two pistons, and thence through the bores 81 and 82 into the space below the larger piston and thus into the pipe 65. When there is no pressure or a low pressure in the receiver 45, the high precsure steam entering through the port Wand acting'on the annular area of the larger piston below the space '78 will push the composite piston down and unseat'the upper edge of the larger piston from the seat '79 and allow steam to pass into the space and thence through the bores .in the pistons and into the pipe 65 for starting purposes. When the valve is unseated, the high vpressurelsteam can act on a projected area equal .to the total area of the larger piston minus the area of the smaller piston and can thus maintain the valve unseated until the pressure in the receiver is great enough so that its effect on the total area (the underside) of the larger piston overbalances the effect of the high pressure steam onthe upper side. When once closed, a greater difference in pressure is required to open the valve because of the smaller area exposed to high pressure steam when closed. The valve 66 is thus an automatic valve, allowing steam to flow into the receiver volume when the pressure in the receiver is below a predetermined maximum and preventing fiowwhen the pressure is above that predetermined maximum.

It may sometimes be advisable to provide for manual control of the flowof by-pass steam into the receiver volume, in which case a valve similar to 66 may be provided for pneumatic control from the cab such as disclosed in Fig. 5. Here the valve parts are the same as those described in connection with Fig. 4 except that instead of the head 72 on the end of the smaller cylinder,

there is arranged on the upper end of the valve j' the space 85 is vented to the atmosphere as at 88. .Above the piston 86 the space 89 is in communication with the source of compressed air supply of the locomotive, controlled by an engineers valve, through the'pipe 90 so that the bypass valve can be held open, if desired, by the engineer irrespective of the receiver pressure, but

will closeautomatically when the air pressure is removed from the auxiliary piston, if the pressure in the receiver is sufficiently high.

The advantages of the construction above de- 1'.

scribed 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-oii valve enables a high pressure locomotive or, in fact, anysteam engine .of variable speed to be operated more economically and with better main valve functioning. It allows an earlier cut-ofi than is possible with an 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 of a receiver volume of about one-third of the cylinder capacity allows for a better use of the full expanson possibilities of the very high pressure steam. The advantages of late cut-off for starting. are obtained in a simple manner without adding to the necessary manual controls in the cab.

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

1. In a steam engine, in combination, a cylinder, a piston reciprocable therein, a main valve adapted to control admission and to provide the maximum cut-on ever required, a cutofi valve between the source of steam and the main valve, said cut-off valve providing as its maximum cut-off that required at normal operating speeds, a pipe adapted to by-pass steam around said cut-oiI valve, and means to prevent flow through said pipe when the pressure in the main valve chamber reaches a predetermined amount less than that of the source of steam supply. i

2. In a steam engine, in combination, a cylinder, a piston reciprocable therein, a main valve adapted to control admission and to provide the maximum out-01f ever required, a cut-off valve between the source of steam and the main valve, said cut-off valve providing as its maximum cutoff that required at normal operating speeds, a

ipe adapted to by-pass steam around said outoff valve, and automatic means to prevent flow through said pipe when the pressure in' the main valve chamber reaches a predetermined amount less than that of the source of steam supply.

3. In a steam engine, in'combination, a cylinder, a piston reciprocable therein, a main valve adapted to control admission and to provide the maximum cut-oil ever required, a cut-'ofi valve between the source of steam and the main valve, said cut-oil valve providing as its maximum cutoii that required at normal operating speeds, a pipe adapted to by-pass steam around said cutoff valve, automatic means to prevent flow through said pipe when the pressure in the main valve chamber reaches a predetermined amount less than that of the source of steam supply, and means to disable the automatic means at will as desired.

4. In a steam engine, in combination, a cylinder, a piston reciprocable therein, a main valve adapted to control admission and to provide the maximum out-ofi ever required, a cut-ofi valve between the source of steam and the main valve, said cut-ofi valve providing as its maximum cutoff that required at normal operating speeds, a pipe adapted to by-pass steam around said cut -off valve, automatic means to prevent flow through said pipe when the pressure in the main valve chamber reaches a predetermined amount less than that of the source of steam supply, and pneumatically controlled means to control the operation of said automatic means.

. 5. In a steam engine, in combination, a cylinder, a piston reciprocable therein, a main valve chamber, a main valve therein adapted to control admission and to provide the maximum cutoff ever required, a cut-off valve between the source of steam and the main valve chamber arranged to provide as its maximum cut-ofi that required at normal operating speeds, means to admit steam tosaid main valve chamber for starting purposes during the period from cut-off by the cut-oiI valve to cut-off by the main valve, and further means to prevent the flow of steam to the main valve chamber when the pressure therein has a predetermined differential in pressure below that of the main steam supply.

6. In a locomotive, in combination, a cylinder, a piston therein, a main valve chamber having a valve therein, means providing a receiver volume for steam ahead of the main valve and of a capacity greater than 20% of the cylinder volume, said valve being adapted to control admission, cut-off, release and compression, a cut-oil Valve chamber adjacent the main valve chamber, a cutoff valve therein adapted to control flow of steam to said receiver volume, a by-pass around said cut-off valve and a valve in said by-pass controlled by diiierence in pressures on the two sides thereof.

7. In a locomotive, in combination, a cylinder, a main valve casing having a valve therein, means providing a receiver volume for steam ahead of the main valve and of a capacity greater than 20% of the cylinder volume, said valve being adapted to control the conjugate events for piston operation, a cut-off valve casing'adjacent the main valve casing, a cut-off valve therein adapted to control how of steam to said receiver volume, a by-pass passage around said cut-01f valve, a valve in said passage and means associated with said valve to control it in accordance with pressure differencesexisting between the said valve casings;

8. In a locomotive, in combination, a cylinder, a main valve casing having a valve therein, means providing a receiver volume for steam ahead of the main valve and of a capacity greater than 20% of the cylinder volume, said valve being adapted to control the conjugate events for piston operation, a cut-ofi valve casing adjacent the main valve casing, a cut-off valve therein adapted to control flow of steam to said receiver volume, a by-passpassage around said cut-off valve, a valve in said passage, a piston operatively connected to said valve and exposed to the pressure of steam in said receiver volume at all times, a second piston of less area connected to said valve and subject to the pressure or steam in said cut-off valve casing, said first mentioned piston serving to close said valve when the receiver volume pressure is a predetermined amount less than the cut-01f valve casing pressure.

9. In a locomotive, in combination, a cylinder, a main valve casing having a valve therein, means providing a receiver volume for steam ahead of the main valve and of a capacity greater than 29% of the cylinder volume, said valve being adapted to control the conjugate events for piston operation, a cut-oiI valve casing adjacent the main valve casing, a cut-off valve therein adapted to control flow of steam to said receiver volume, a by-pass passage around said cut-ofi valve, a valve in said passage, a piston operatively connected to said valve and exposed to the pressure of steam in said receiver volume at all times, a second piston of less area connected to said valve and subject to the pressure of steam in said cut-off valve casing, said first mentioned piston serving to close said valve when the receiver volume pressure is a predetermined amount less than the cut-off valve casing pressure and means for opening said valve against the said first piston at will.

10. In a steam engine, in combination, a source of steam, a main valve chamber, a cut-off valve between said source and chamber, a starting mechanism including a pair of coaxial cylinders of two diameters, a valve seat between said cylinders, a combined piston and valve in the larger cylinder, a piston in the smaller cylinder and directly connected to the larger piston, means exposing the face or' the smaller piston to atmosphere, means exposing the face of the larger piston to pressure of steam in the main valve chamber, means exposing the difierential area of the pistons to steam at the pressure of said source only when the valve is open, and means whereby said last mentioned steam acts on less than said differential area when the valve is closed;

11. In a steam engine, in combination, a source of steam, a main valve chamber, a cut-off valve between said source and chamber, a starting mechanism including a pair of coaxial cylinders of two diameters, a valve seat between said cylinders, a combined piston and valve in the larger cylinder, a piston in the smaller cylinder and di rectly connected to the larger piston, means exposing the face of the smaller piston to atmos phere, means exposing the face of the larger piston to pressure of steam in the main valve chamber, means exposing the diiierential area of the pistons to steam at the pressure of said source only when the valve is open, means whereby said last mentioned steam acts on less than said differential area when the valve is closed, and a passage connecting said differential area to the face of the larger piston.

12. In a steam engine, in combination, a source of steam, a main valve chamber, a cut-off valve between said source and chamber, a starting mechanism including a pair of coaxial cylinders of different diameters, a valve seat between said cylinders and of an intermediate diameter, a composite piston for said cylinders having a portion' fitting each cylinder and a portion cooperating with said valve seat, a closure for the large cylinder, means conveying steam from said source to the larger cylinder near the valve seat, an annular area on said larger piston exposed to pressure from said steam when the valve is closed, a passage through the piston from the head of the larger portion to a position on the small cylinder side of the valve part, and means connecting the larger cylinder to the main valve chamber.

WILLIAM F. KIESEL, JR.

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