US2074165A - Expansion engine - Google Patents

Description

J; M. CLARK EXPANSION ENGINE March 16, 193'17.

Filed Aug. 2l, 1955 2 Sheets-Sheet l March 16, 1937. g, M CLARK 2,074,165

EXPANS ION ENGINE Filed Aug.'211955 2 sheets-sheet l2 /f u INVENTOR. Jam Mem# am.

l WLM' ATTORNEYS.

Patented Mar. 16, 1937 UNITED? sTA'rEs i .2nuits OFFICE 14 Claims.

This invention relatesto expansion engines, especially to engines havingv a fluid-pressure cylinder with a piston Working therein, and admission and exhaust ports controlled by a main valve, and more particularly to such Vengines which are characterized by an auxiliary exhaust passage controlled by an auxiliary exhaust valve.

A primary object of the present invention is to provide, to an extent heretofore unrealized, for relieving back pressure in the cylinder by permitting a complete free exhaust therefrom independently of that permitted by the main valve; also, in pursuance of this primary object, another object is to provide for connecting the auxiliary l valve to appropriate Working parts of the engine,

and preferably to the main reverse-shaft-link, in

such a manner that full motion will be imparted thereby to effect free exhaust to an optimum extent.

Another object is to provide means by which the operation of the auxiliary free exhaust valve gear will be under direct manual control of the engineer, by .governing means independent of the usual means for controlling the main valve,

but conveniently disposed in relation thereto for manual operation, as in the cab of a locomotive.

Another object of the invention is to provide for throwing the auxiliary valve gear entirely out of `operation at the will of the engineer without in any Way aiecting normal operation of the main Valve gear.

Still another object is to provide for effecting the last-named object by means of a device acting in aid of the auxiliary exhaust valve, but permitting the latter to idle without functioning, at

times when free exhaust is not desired; also to utilize for this purpose a piston-'type valve as the auxiliary valve, and a` sleeve member disposed telescopically upon this piston valve, with a lever controlling-system running to the cab by which the sleeve may be set readily at any time to cut 01T the exhaust entirely, or to set it at any degree of cut-off without affecting the coordinative relation between the valves.

Other objects and advantages will appear as the description of the particular physical embodiment selected to illustrate the invention progresses, and the novel `features will be particularly pointed out in the appended claims.

In describing the invention in detail, and the particular physical. embodiment selected to illustrate the invention, reference Will be had to the accompanying drawings and the several views 5,-; thereof, in which like characters of reference designate like parts throughout the several views, and in which:

Fig. 1 is an elevation of the invention, partly in section through the driving cylinder-and the main and auxiliary valve casings;

Fig. 2 is a fragmentary,`detail view of a part of the mechanism shown in Fig. l, illustrating certain of the parts in a different operative position;

Fig. 3 is a vertical section taken on the line 3-3 of Fig. 1;

Fig. 4 isa fragmentary, detail View similar to Fig. 2, showing a modication;

Fig. 5 is a similar view illustrating another modication.

In the now-preferred embodiment of the invention selected for illustrative disclosure thereof, the part designated by the reference character II is the duid-pressure cylinder of an expansion engine upon a steam-propelled locomotive, and I 2 designates the piston working therein, I3 being the piston-rod, I4 the cross-head, I5 the main driving-rod, running to crank-pin I6 of driving Wheel Il; I8 is the eccentric-rod, running to arm I9 on the main reverse-link 22; 20 is the reverse shaft, 2l the reverse-shaft-arm, 23 the lifting-link and 24 the reverse-shaft-lever; these forming parts of connections running to the cab of the engine (not shown), to permit manual control thereof by the engineer.

The valve gearY and associated parts designated as above may be in general of the conventional form illustrated, or of other suitable construction, as are also the main valve 25, shown as a piston valve operating in a steam chest Z6 having a suitable main admission passage 2l', and main admission and exhaust ports 28 and 29: main exhaust passages are shown at 3l and 32', and 30 designates suitable orifices in the valve-seatliners 33, the ports designated as above being all adapted to be controlled by the main valve 25, which is in turn actuated and controlled by suitable connections Wth the main link 22, such connections preferably including a radius-rod 34, anda combination-lever of conventional form as 35, 36, associated with the cross-head I4, by which it may desirably be actuated in the manner characteristic of the so-called Walschaert valve gear, or of any other analogous or suitable valve gear, the particular form shown being merelyillustrative and not limitative.

In an extension of the valve chest, as 31, is

shown an auxiliary valve 38, taking the form, in

the instance' illustrated, of a` piston valve, al-

though by such illustrative disclosure it is not intended to exclude the use of other suitable forms of valves; this auxiliary valve being adapted to control auxiliary passages 39 and 40, either 5 of which is adapted, selectively, to permit full and free exhaust from the main cylinder when so desired, independently of the exhaust controlled by the main valve 25.

As a convenient and suitable means to operate l this auxiliary valve 38, its stern 4| is connected to the main link 22, as by a pivot 42 from which a rod 43, or system of rods and levers designated generally by the reference character R, runs to a pivot 45 on main link 22, and in the preferred l form of the invention illustrated in Figs. 1, 2 and 3, I have shown a secondary link 44 mounted swingingly about a pivot post 46 carried by the frame F, the secondary link 44 constituting an adjustable element or instrumentality in connection with a pivot block 4 upon which is carried lever 43 by a stud 43a said block being movable slidingly in the body slot 3 of link 44. The

end 48 of lever 43 is connected pivotally, as by a lifting link 49, (which may be termed the secondary lifting link, as it is identical in form with the main lifting link 23) With the bell-crank lever 50, which forms part of a system of levers designated generally A, running to the engine cab (not shown), to permit manual control by the engineer of the auxiliary valve independently of the usual control of the main valve through main link 22, as already described.

The various operations of this secondary link will be described more at length hereinafter, but it should be noted that when it is adjusted to the mid-position shown in Fig. 2, or rather when the pivot block 4 is adjusted so as to bring the pivot stud 43a into axial registration with the pivot point 45 of the secondary link, as in Fig. 2, the auxiliary valve 38 will be put thereby entirely out of operation, and the main valve will` then be relied upon to take over the entire government of exhaust operations, in normal fashion, and completely without interference. 45 So far as I am aware, this provision for effecting a full stroke of such an auxiliary valve to permit complete free exhaust under selective control by the engineer at all times, has never been made before, and I regard this notable improvement in the art as constituting the underlying idea of means to which my claims are directed generically except so far as otherwise limited to particular physical embodiments of the said idea of means. 55 It will be readily understood from the foregoing disclosure that when the parts are in the relative positions illustrated in Fig. 1, steam will be admitted to the front end I9 of cylinder following the course indicated by the arrows in Fig. 1, the main steam supply entering the chest 26 from S through port 2'1, and leaving the chest through the orifices 30 in bushing or liner 33, which are at all times in communication with ports 28, through which the live steam has ac- 65 cess to the front end of the cylinder.

The main valve at this event is disposed with its front piston m' in position to block exhaust to the main exhaust passage 32, and the auxiliary valve 38 is so disposed as to block the auxiliary exhaust passage 49 by means of the auxiliary valve piston a; while at the other ends of the main valve and of the auxiliary valves respectively, the valve piston m of the main valve and the valve piston a of the auxiliary valve are so disposed as to leave the main exhaust passage 3| and the auxiliary exhaust passage 39 wide open for spent steam passing through passage 29 and orifices 30 in the liner 3 also having access to the main exhaust passage through an orice 5| provided between the auxiliary and main exhaust passages. It is to be understood that the auxiliary passages 39 and 49 respectively surround the liners or bushings 33, so that when either of the valve pistons a or a, as the case may be, occupies its innermost position, as that occupied in Fig. 1 by the piston valve a, for example, the steam proceeding from port 29 will be given free and full opportunity to exhaust, regardless of whether the valve piston m of the main valve occupies the position illustrated in Fig. 1, or whether the main valve 25 has been retracted to a position in which said piston valve m" covers the orices 30 in Whole or in part.

It is also true that when one of the piston valves of the auxiliary valve occupies its outermost position, as in the case illustrated in Fig. 1 with respect to the valve piston a', the auxiliary exhaust passage controlled thereby will be closed, as is the passage 40 in Fig. 1. In the instance illustrated the main exhaust passage 32 is completely closed, also, but it will be understood that the auxiliary valve may be disposed to close the auxiliary exhaust passage completely even when the main exhaust passage is desirably open in whole or in part, as during the event of starting the engine, or at such times the auxiliary exhaust may also be opened in Whole or in part, its regulation being entirely under the manual governance of the engineer, by means of the lever system A, independently of the regulation of the main valve, as already disclosed.

Accordingly the main valve can be linked up or cut olf to any point for high speed work, independently of the free exhaust valves, and my novel arrangements for operating the auxiliary valves will give a free exhaust While the main valve is traveling a short stroke on cut off, and thus my invention accomplishes the primary object stated in the opening paragraphs of this specication, viz., to provide, to an extent heretofore unrealized, for relieving back pressure in the cylinder while permitting a complete free exhaust therefrom independently of that permitted by the main valve. I have found on test that with a 50% cut-off on the main valve and the auxiliary valves wide open for complete free exhaust, I am able to effect a gain of at least 20% in power, and the gain is in proportion to the size of the engine.

The particular physical embodiment of the invention shown in Fig. l is merely illustrative, as already mentioned, and as an indication of possible changes or modifications of structure to meet the requirements of particular installations, or to eiect economies of space, I have shown in Fig. 4 an arrangement of parts in which the various instrumentalities that bear reference characters corresponding to those of Fig. 1, may be regarded as similarly formed and co-operating in the same fashion; but it will be noted that the secondary link 44A shown in Fig. 4 is provided with a relatively long arm or extension 54, and that the rod running from this part to the main link 22 is connected pivotally to the latter at the same pivotal point 58 to which is connected the eccentric rod i8.

It will also be noted that the pivot point of the secondary link support 51 is disposed at the upper end of said link and a somewhat longer adjustive range of movement has been provided for, all at one side of the pivot point 51.

lnanother modification of the invention, as

shown in Fig. 5, I have provided in a suitable extension 60 of the valve casing a cylindrical seat 6l, 62, having main exhaust passagesv and .ports 63, 64, and auxiliary exhaust passages and ports 65, 66.

The auxiliary valve 68 in this device is of the pistonv typeV and has piston valves p' and p" so disposed that` when the engine is to be backed up these valves will close the main exhaust ports, as illustrated.

In this structure, the valve`istem61 is connected to the main link 22 by mechanismincluding link 69, lever 1B and link 1| operating in well-known reversal of the direction of motion derived from main link 22, and the auxiliary piston valves continue to reciprocate aslong as the main link 22 operates. The sleeve 12 as shown in this figure is provided with a system of levers designated generally by the reference `character L, which may desirably be extended to the engine cab, (not shown) so that the sleeve may be shifted independently of the operation of theV main valve b-y the means hereinbefore described with respect to other embodiments of the invention.

By operation of the lever system L manually, the sleeve 12 may be set at any desired position within its range of movement; viz, from one extreme position in which all o-f the parts are cut oil?,- so that the auxiliary valve mechanism idles (i. e., is ineiective, though moving), to a position in which, asshovvn in Fig. 5, al1 of the parts 13, 14, 15 and 16 are open, affording complete free exhaust. By setting the sleeve 12 suitably to a selected intermediate position the parts may be cut Oi tothe extent desired, in which latter instance ports 16, 13, 14 andV 15, in the extension will be brought suitably Vinto registry` with appropriate portions of the ports 63, 64, 65 and 66.

I have described what I believe to be the best embodiments of my invention. I do not Wish, however, to be conned to the embodiment shown, but what I desire to cover by Letters Patent is set forth in the appended claims.

I claim:

1. A valve gear for an expansion engine of the type characterized by a fluid-pressure cylinder with a reciprocating piston working therein and having main admission and exhaust ports and a main valve adapted to control said ports for general admission and exhaust purposes; said valve gear being further characterized by an auxiliary exhaust passage and an auxiliary exhaust valve exclusively for controlling exhaust through said last-named passage, and means to permit selective manual control of said valves at all times, whereby complete free exhaust from said cylinder is provided.

2. A valve gear for anexpansion engine of the type characterized by a fluid-pressure cylinder with a reciprocating piston Working therein and having an admission port, a main exhaust passage, a main exhaust port, a main valve adapted to control both of said ports for general exhaust purposes, and means for actuating and controlling said main valve; said valve gear being further characterized by an auxiliary exhaust passage and an auxiliary exhaust valve for controlling said last-named passage, whereby free exhaust from said cylinder may be permitted independently of control by the main valve; and means to control said auxiliary valve independently of the main valve.

3. A valve gear for an expansion engine of the type characterized by a fluid-pressure cylinder witha reciprocating piston Working therein, and havingV an admission port, a main exhaust passage, a main valve adapted to control said port and Apassage for general exhaust purposes, and means for actuating and controlling said main valve, including a conveniently disposed manual governing device for said main valve; said valve gear being further characterized by an auxiliary valve and an auxiliary passage controlled thereby, whereby free exhaust from said cylinder may be permitted independently of the main exhaust, and also characterized by manually operable governingvmeans `for said auxiliary valve disposed conveniently vnear to said first-named governing device butoperable independently thereof.

4. A valve gear for an expansion engine of the type characterized by a fluid-pressure cylinder with a reciprocating piston Working therein and having an admission port, a main exhaust passage, a main valve adapted to control said port and passage for general exhaust purposes, and means for actuating and governing said main valve, including a main reverse link combined and co-operating with appropriate working parts of the engine; said valve gear being further characterized by an auxiliary `valve and an auxiliary exhaust passage controlled thereby, said auxiliary valve being -provided with connections to said main link, whereby free exhaust from said cylinder may be permitted independently of the main exhaust, and means to control the operation of said auxiliary valve manually, independently of said main valve. l

5. A valve gear for a steam engine orlike expansion engine of the type characterized by a fluid-pressure cylinder and a piston working therein and having an admission port, a main exhaust passage, a main valve adapted to control said admission and exhaust generally, and means for actuating and governing said main valve including a main reverse link, combined and cooperating with appropriate working parts of the engine, said governing means including a device conveniently disposed for manual government of said main valve; said valve gear being further characterized by an auxiliary valve and an auxiliary exhaustpassage controlled thereby, whereby free exhaust from said cylinder may be permitted independently of the main exhaust, said auxiliary valve having direct, adjustable, connections with said main link, and manual governing means to adjust said connections for said auxiliary valve, said last-named governing means being arranged in convenient disposition for operation independently of said first-named governing device.

6. A valve gear characterized by the elements combined and co-operating as set forth in claim 1, said valve gear being further characterized by having said auxiliary valve formed as a reciprocating piston and by having a sleeve surrounding said piston valve slidingly as an instru-- mentality of said auxiliary-valve-control means; andmeans operable manually to move said sleeve to cut off said free exhaust at will, irrespective of Whether or not said main exhaust is open,

7. A valve gear of the class described, comprising a main valve adapted to control the main admission and exhaust normally; an auxiliary valve adapted to control an auxiliary passage for free exhaust, being arranged for normal operation in supplement of the main exhaust, and means to cut off said auxiliary exhaust passage at will, while said auxiliary valve continues to move.

8. A valve gear forA expansion engines of the type characterized by a fluid-pressure cylinder with a reciprocating piston working therein and having an admission port, a main exhaust passage, a main exhaust port, a main valve adapted to control said admission and exhaust normally, and means for actuating and governing said main valve; said valve gear being further characterized by an auxiliary exhaust passage and an auxiliary valve for controlling said last-named passage, means to co-ordinate the operation of said main and auxiliary valves whereby free exhaust from said cylinder may be permitted through said auxiliary passage free from control by said main valve, and means to control said auxiliary valve independently of said main valve.

9, A valve gear characterized by the elements combined and co-operating as set forth in claim 8, and further characterized by having said auxiliary-valve-control means formed with a secondary link and adjusting means therefor.

10. A valve gear characterized by the elements combined and co-operating as set forth in claim 8, and further characterized by having said auxiliary-valve-control means provided with a secondary link, and adjusting means comprising a system of manually operable levers and a pivot block connected to said auxiliary valve and working in said secondary link.

11. A valve gear characterized by a main valve link, connected to the working parts of an expansion engine for controlling admission and exhaust of the fluid pressure medium, and also characterized by an auxiliary valve having a secondary link connection with said rst-named link,

whereby said secondary link and auxiliary valve are co-ordinated with, and actuated by, said rstnamed link, each of said links being provided with means for adjustment of one link motion independently of the other.

12. valve gear characterized by a main valve link, connected to the Working parts of an expansion engine for controlling admission and exhaust of the fluid pressure medium, and also characterized by an auxiliary valve having a secondary link connection with said first-named link, whereby said secondary link and auxiliary valve are coordinated with, and actuated by, said firstnamed link, each of said links being provided with means for a reversal of one link motion independently of the other.

13. A valve gear characterized by a main valve link, connected to the Working parts of an expansion engine for controlling admission and exhaust of the uid pressure medium, and also characterized by an auxiliary valve having a secondary link connection with said first-named link, whereby said secondary link and auxiliary valve are coordinated with, and actuated by, said rst-named link, each of said links being provided with an arm, said arms being extended in the same direction and being connected pivotally with a common rod which serves to connect and co-ordinate the movements of said links while permitting independent adjustment of each; said gear being also characterized by means for eiecting manually and selectively said adjustments.

14. A valve gear for an expansion engine of the type characterized by a Huid-pressure cylinder with a reciprocating piston working therein and having main admission and exhaust ports and a main Valve adapted to control said ports for general admission and exhaust purposes; said valve gear being further characterized by an auxiliary exhaust passage and an auxiliary valve therefor, with means to control said auxiliary valve selectively to provide free exhaust in any cut-off position of the main valve.

JOHN MERRITT CLARK.

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