US794881A - Variable-exhaust mechanism. - Google Patents

Description

PATENTED JULY l, 19N.

BEST MA1LN3\.L=.l @Op 0.1.. PAGBN'HART'. VARIABLE EXHAUST MSCHAMSM.

AYPLIGATIN FILED 00T. 12, 1904.

BEST AVAlLABLE CO2" UNITED STATES Patented July 18, 1905.

PATENT OEEICE.

TI-IIRDS TO DAVID R. TENNILLE, GEORGIA.

THOMAS AND JULIUS BASHINSKI, JR., OF

VARIABLE-EXHAUST MECHANISNI.

'SPECIFICATION forming part of Letters Patent No. 794,881, dated July 18, 1905. Application filed October l2, 1904. Serial No. 228.213.

To {LZZ whom, it may concern;

Be itknown that I, CHARLES L. PAGENHART, a citizen of the United States, residing at Tennille, in the county of Washington and State of 5 Georgia, have invented certain new and useful Improvements in Variable-Exhaust-Mechanism for Application to Steam-Engines Wherever Such a Device is Desirable to be Employed; and Ihereby declare the following to 1o be a fulhclear, and exact description of the sama-reference being had to the accompanying drawings, in which-- Figure 1 is a vertical central section of a mechanism embodying my in vention,shown in connection with the exhaust-column and exhaust-column bridge of a locomotive to control the 'exhaust thereof. Fig. 2 is an enlarged detail section of a portion of the exhaust-column, showing the eolumn-bridge-ad- 2O justing cam mounted therein, and a portion of one section of the adjustable column-bridge. Like symbols refer to like parts wherever they occur.

Myinvention relates to that class of devices especially designed to govern or control the exhausts of steam-engines, but generally applicable for exhaust purposes under similar conditions, and has for its objects to produce a mechanism which shall automatically increase or decrease the draft accordingly as the steam-pressure may fall below or risc above the normal and to generally reduce the back pressure, as well as prevent the back pressure of one cylinder upon an'opposite cylinder, 3 5 thereby saving a large percentage of the fuel ordinarily necessary, while at the same time producing a more eiiicient engine and locomotive of increased and more uniform speed and power. Hitherto in the construction of va- 40 riahle-exhaust mechanism designed to accomplish these several before-noted objects cones or other devices adapted to vary the area of the opening in the exhaust-nozzle have been commonly employed, or flap or other valves have been used; but a construction such the former type impairs the eflicient working of the engine by reasonof the back pressure created by the obstruction thus placed cen- `haust-oolumn preferably slightly` above trally of the exhaust-nozzle, and devices of the latter type generally produce cross-firing of the exhaust in the stack and soon become inefficient by reason of the constant vibration and oscillation to which they are subjected when in service.

To accomplish the before-noted objects and to overcome the objections pointed out, I combine with the exhaust-column of an engine an exhaust-column bridge separating the cylinder exhaust-ports, said bridge having upwardly-diverging sides and having its upper extremity adjacent to the choke of the exthe same.

A second feature of my invention resides in so arranging and constructing the exhaustcolumn bridge that the exhaust area of the g exhaust-column may be varied by a change in the form of the said exhaust-colummbridge'.

A third feature of my invention resides in the means for automatically adjusting and controlling the exhaust-column bridge, said means comprising a` plurality of differentlygraduated 'valvesinterposed between a common source of pressure and a cylinder the movement of whose piston actuates the""ad justable exhaust-column bridge by any suitable connections.

A fourth feature of my invention resides in an automatic exhaust-valve mechanism for the cylinder whose piston actuates the exhaustcolumn bridge.

There are other minor features of invention" residing in particular coi'nbinations and elemental constructions, all as will hereinafter more fully appear and be particularly pointed out in the claims.

I will now proceed to describe my invention more fully, so that others skilled in the art to which it appertains may apply the same.

lrVhile I have illustrated my devices as applied to a locomotive, yet it will be Linderstood that my invention as pointed out inthe claims is of broader scope and may be applied to any engine wherein a forced draft is desirable, and similarly the automatic means BEST AVAlLABLE CO?" for controlling the form and size of the adl justable column-bridge and the means for automatically controlling the exhaust of the cylinder which actuates the column-bridge are of more general application in the arts.

In the drawings, A is the smoke-box of a locomotive, having therein an exhaust-column B, the lower end of which is secured to the cylinder-saddle (not shown) connected to the cylinders (not shown) through usual and wellknown exhaust ports or in other suitable manner. The exhaust-column B is preferably gradually contracted in area to the choke l thereof and from thence is preferably increased in area for at least a part 2b of its remaining length, the converging Walls of the lower portion of -said exhaust-column B, if prolonged, preferably meeting at a point in the longitudinal axis of the stack (not shown) and adjacent to the lower end' of the latter; but, if desired, any other suitable form of exhaust-column may be employed.

Within the exhaust-column Band interposed between` the exhaust-ports connected to the cylinders in such manner as to divide said exhaust -column into two independent compartments is the exhaust-column bridge C, which is -preferably constructed with upwardly-diverging sides and which terminates at oradjacent to the choke 1b of the exhaustcolumn B, the outwardly flaring or diverging sides directing the exhaust centrally upward through 4the column and counteracting the tendency of the-exhaustesteam to cross to the opposite Side ofthe column and to create back pressure on the opposite cylinder, thus 'preventing any decrease of the effective pressure upon suoli. opposite cylinder. By this means also the exhaust-steam from one cylinder does not cross the path of the exhauststeam .from the other cylinder, and the swirl.

ing of the steam, which is so detrimental to a perfect draft and a free exhaust, is obviated. The exhaust-column. bridge C, which, as will hereinappear, is a means for regulating the draftin the stack, is preferably constructed of a plurality of resilient sections 1c 1, which are bolted or otherwise secured to the columnbridge base 2c, the latter being rigidly fas-- tened to the base of the exhaust-column intermediate the cylinder exhaust-ports leading thereinto, said resilient sections 1c 1c having their upper ends bent inwardly to overlap and closely engage each other, thus forming a closure for the top of said adjustable column-bridge and permitting a relative movement toward and from each other of the two sections. If desired, the edges of the resilient members 1 lc may be provided with spring-pressed packing-strips which engage the fiattened walls 3" 3" of theexhaust-column B, thus preventing any possible leakage from one exhaust-compartment to the other exhaust-compartment of the said exhaustcolumn.

\Vhile I prefer to form the sections lC 1 of the adjustable exhaust-column bridge C of resilient material such that the said sections will always have a tendency to approach each other, yet it is obvious that this function may be accomplished by a spring interposed between the sections and bearing upon each. It is apparent also that the sections 1e l'3 of the adjustable exhaust column bridge may be constructed of a single piece of metal formed into the proper shape.

The cam-shaft D, to which is secured the cam E, is -iournaled in the exhaust-column B near the choke l" thereof, one of its ends engaging the corresponding socket 4f" of the said column B, (see Fig 2,) the other end passing through a thimble 1d, which engages the interiorly-threaded nipple 5b of the exhaust-column; but, if desired, other means may be employed for this purpose.

The cam or double eccentric E, which is interposed between the resilient sections 1I 1c of the exhaust-column bridge C and is a means both for adjusting-the said sections lC l and retaining them in an adjusted position, is preferably formed with a square aperture running axially therethrough for engaging a correspondingly-formed portion of the cam-shaft D, said cam being thereby fixed to its shaft in respect of any relative turning movement; but other well-known means-as, for example, a key or spline-may be employed to secure the cam to its shaft.

Rigidly attached in any suitable manner to that end of the cam-shaft D which passes through the exhaust-column B is the lever or crank F, said crank having its opposite end flexibly secured to the reach -rod Gr by a knuckle-joint or other connection of like character.

For the purpose of readily adapting the device to different locomotives, as well as to relatively adjust the parts and to readily assemble the same, I prefer to form the reach-rod G of a plurality of sections l 1"', connected by a turnbuckle 2, the latter being engaged by thejam-nnt 3g, which restrains any movement of the latter, and thus affords a means for securing the sections of the reach-rod in a fixed relation;` but other means whereby the reach-rod may be rendered extensible in character may be employed, or the reach-rod may be constructed as an integral member.

Bolted or otherwise secured upon the exterior of the smoke-box is a bracket H, preferably com prising a baseplate l, con forming to that part of the locomotive to which it is applied, and an open yoke 2", the said baseplate and yoke being each provided with a stuffing-box of any usual or suitable construetion either made integral therewith or detachable therefrom.

fliile l prefer to locate the bracket ll, which forms the-,support for the cylinder con- IOO IIO

trolling the exhaust-column bridge C, con-30 tiguous to the sm oke-box, yet said bracket and the mechanism carried thereby may obviously be located in any other suitable position upon the engine or locomotive.

Secured to the bracket H by bolts passing through an angular fiange or in other suitable manner is the cylinder K, the head 1k whereof is provided with ahand-wheel 2k and attached threaded rod 3, having threaded engagement with the said cylinder-head 1k, by which means the length of stroke of the piston or other movable member L Within the cylinder K is limited and by which primarily the minimum area of the exhaust-opening of the exhaustcolumn is regulated through the cam or double eccentric E, which controls the relative 'position of the resilient'members 1c 1c, constituting the adjustable exhaust-column bridge C; but, if desired, other meansrfor regulating the minimum area of the exhaust and the corresponding maximum separation of the adjustable members of the said column-bridge may be employed.

Vithin the cylinder K isa piston L-ovair'iywell-known orsuitable construction, the piston-rod whereof is exibly connected to the reach-rod G, preferably by a knuckle-joint, said piston-rodl passing through and being guided-by the stuing-boxes of the vbracket H.

The cylinder K is provided with ports l4" 5k for the admission of steam to the cylinder on opposite sides of the piston and isalso pref-v erably provided with corresponding leakage-f. grooves orexbaust-ports 6k7kof comparatively-'g small area for the escape of steam and of water of condensation; but, if desired, automat-- ically-controlled exhaust-valves may be substituted for such leakage grooves or ip orts, or.

bib-cocks or other valves may be .employed in addition to such leakage ports orvalves.

When automatic exhaust-valves arel desired to control the leakage-grooves or exhaustports 6k 7k of main cylinder K, I preferably employ the means therefor devised by me and i shown in the drau-'ings-A-that is .to say', I secure to the cylinder K adjacent or in line with the exhaust-ports 6k 7k valve-cases or supplemental cylinders W W', each of which is connected with the opposite end of main cylinder K by a live-steam port or passage 8 (or 8W) and provided with an exhaust-port 9, (or 9`v,) and within each of said valve-cases I provide a piston X (or X') or diaphragm, which is connected with the adjacent valveY, (or Y',) which controls the exhaust-port 6k, (or 7k,) so that when there is no pressure or the pressure is uniform on both heads of piston L of main cylinder 'K said valve Y (orY) remains.

seated; but as soon as the pressure becomes greater upon one headof the piston than on the other the said pressure will act through the port 8 (or 8W) upon piston "X (or X) to open valve Y, (or Y.) The unseating of valve Y at once puts exhaust-port 6 in communicaessi AvAiLAeLE coP tion Withexha'ust-port 8, while the unseating of valve Y puts exhaust-port 7k in communication with exhaust-port 9. It is evident that this automatic exhaustmechanism is applicable tothe control of the leakage or exhaust ports of fluid-pressure cylinders in general.

VMounted upon the-,cylinder K in any snitable manner, as by being threaded thereinto, are the diaphragm-bodies M and N,the same having valved passages therein communicatingwith the ports ik 5", respectively, and also having apertures to receive a pipe or other means for transmitting pressure to the diaphragme O P, as will hereinafter appear.

'Mounted within the respective diaphragmbodies M and N, and preferably secured therein by means of the spring-cases QQ, which are or may be threaded to engage corresponding threads of said diaphragm-bodies are the diaphragms O and P, the latter` being formed, of any suitable flexible material, preferably. Vcopper or brass.

Secured to the diaphragm O is the highpressure valve o, which is adapted to be lifted from its seat Within the diaphragm-body M to admit steam .or other Huid pressure to cylinder K through. the port 4E Whenthe steampressure in the boiler rises above the limit at which said high-pressure Valve o is setto open, the low-pressure Valve p, located; within the diaphragm-body N, being similarly secured to `its :diaphragm P, but being adapted to open -toadmit pressure to thecylinder K through the port-5k When the- -steam-pressure in the yboiler falls below.the pressure at which said -last-namedvalve is set to open. '7 f l In lieu ofrthe diaphragms I may. substitute pistons lWorking in the spring-cases Q Q; but a construction employing such diaphragms is preferable, astlie `opening of the attached valves is thus limited in a very simple manner and a tight steam-joint is readily secured.

- Preferably housed within spring-cases Q, Q

are the springs S S, each of said springs be' ing interposed between one of the diaphragme O P and one of the adjusting-nuts R It, by l which the pressure of such springs upon the diaphragms and attached valves may be graduated.v It will be noted that the springs S S are the preferred moans for mai ntaining a constant pressure of predetermined amount upon the ,respective valves; but other means for IOO IIO

this purpose may he employed, or under suitable conditions of operation the diaphragms themselves vmay be made of the desired difference in stiffness.

The interior chambers of the diaphragmbodies M and N, which open into the cylinder K, are connected to a common source of pressure through the pipe 'l.`v, which connects the diaphragm-bodies and the pipe V, which is supplied with steam at l. oilei'-\;iressurc; but other means may be adopted for this puipose,

if desired-as, for example, each diaphragmbody may be independently connected to the boiler-pressure.

The construction being substantially such as hereinbefore pointed out, the device will operate as follows: rIhe mechanism having been assembled and placed in position on the locomotive, the turnbuckle 2g having been manipulated tomake the reach-rod G of proper length, the desired minimum exhaust area of the exhaust-column at the choke having been fixed by properly adjusting the screw-rod 3k by means of the hand -wheel 2k, and the adjusting-nuts R R having been operated to produce pressure upon the respective valves corresponding to the pressures at which it is desired .they shall open to admit steam to the cylinder K, the live steam from the boiler will pass through the pipes V and T to the interior chambers of the diaphragm-bodies M and N. If at this time the steam-pressure is within the limits of variation it is desired to allow,

such variation being represented by the difference between the spring-pressure upon the high-pressure valve 0, which is designed to open when the steam-pressure exceeds the desired upper limit, and the spring-pressure upon the low-pressure-valve 10, which is designed to open when the steam-pressure falls below the desired lower limit, then both highpressure valve o and low-pressure valve p will remain closed, since the pressure of steam is insuflicient to overcome either spring, and the adjustable exhaust-column bridge will be unaffected and will maintain the exhaust area at the choke of the exhaust-column which it has "been designed or adjusted to have under normal conditions. If now the steam-pressure should rise above lthe upper limit at which'the high-pressure valve 0 is set, such excessive pressure acting upon the diaphragms O and P through the pressure-pipes V and T will overcome the spring-pressure upon the diaphragm O, causing the latter and the attached valve 0 to rise, thus admitting steam to the cylinder K through the port 4k, and the presl sure entering the main cylinder K through Vthe port Ik will pass through that end of-the cylinder and through port 8 to valve-case or supplemental cylinder W and unseat exhaustvalve Y, thus opening the leakage-port 7k to exhaust-port 9. During this time the steampressure upon the diaphragm P is greater than the spring-pressure thereon, and the low-pressure valve p consequently remains closed. It thus results that the piston L is moved in a direction to slightly rotate the cam E and permit the resilient sections lc l of the exhaust-column bridge to more closely approach each other, thereby increasing the exhaust area at the choke of the exhaust-column, and thus permitting a freer exhaust, while at the same time decreasing the draft in the stack. Vhen the pressure of steam in the boiler has dropped by reason of the de- BST AVAlLABLE COF" creased draft until it is below the pressure at which the high-pressure valve 0 is set, such Valve 0 is closed through the spring acting thereon. If now the steam-pressure in the boiler should fall below the limit at which the low-pressure valve p is designed to open, such steam-pressure acting through the pipes V andTwill be communicated to the diaphragms l O and P and will be insulhcient to overcome the springpressure maintaining the highpressure valve closed, but will, permit the spring-pressure upon the low-pressure valve p to open said last-named valve, as shown in Fig. 1, to admit steam to the cylinder K through the port 5k,which steam will also pass through port or passage 8W to valve-case or supplemental cylinder W and unseat the exhaust-valveY, thus opening the leakage-port 6k to the exhaust-port 9W. At the same time the piston L is moved to cause a slight rotation of the cam E, which results in a spreading or separation of the sections 1c l of the exhaust-column bridge, thus decreasing the area of the exhaust at the choke of the exhaustcolumn by changing the form of said columnbridge, andV thereby increasing the draft. When the steam-pressure` in the boiler has risen above the pressure at which the low-- pressure valve is set, such pressure thereupon closes said valve. v

While l have illustrated and described a particular mechanism for automatically actuating my adjustable exhaust-column bridge, yet it is evident that other forms of apparatus may be 'employed for this purpose or that such exhaust-column bridge may be operated manually, and while I have shown and described a preferred means for automatically admitting steam to the cylinder controlling the operation of such adjustable exhaust-column bridge other means for this purpose may he employed-as, for example, a slidevalve or a triplev valve.

vMy invention is susceptible of many modifications and many 'changes in construction and form of parts without departing from the spirit thereof.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, isd

l. In a variable-exhaust mechanism, the combination with an exhaust-column, of an adjustable exhaust-column bridge within said exhaust-column, substantially as and for the purposes specified.

Q. In a variable-exhaust mechanism, the combination with an exhaust-column, of an adjustable exhaust-column bridge within said exhaust-column, and means lfor adjusting said exhaust-column bridge, substantially as and for the purposes specified.

3. In a variable-exhaust mechanism, the combination with an exhaust-column, o f an adjustable exhaust-column bridge within said exhaust column, and pressure controlled IXO means for automatically adjusting said exhaust-column bridge, substantially as and for the purposes specilied. l Y

4. In a variable-exhaust mechanism, the combination with an exhaust-column, of an exhaust-column bridge Within said'exhaustcolumn, said bridge havingupwardly-diverging walls, substantially as and for the purposes specilied.

5. In a variable-exhaust mechanism, the combination with an exhaust-column, of an exhaust-column bridge within said exhaustcolumn, said bridge comprising a plurality of relatively movable sections, substantially as and for the purposes specified.

6. In avariable-exhaust mechanism, the combination with an exhaust-column, of an exhaust-column bridge within said exhaustcolumn, said bridge comprising aplurality of resilient sections, substantially as and for the purposes specified.

7. In a variable-exhaust-mechanism, the

'combination with an exhaust-column, of an exhaust-column bridge within. said exhaustcolumn, said bridge adapted tov vary the exhaust area of said exhaust-column by-a variation in form of the saidexhaust-eol umn'brid ge, substantially as and for the purposes specitied.

8. In a variable-exhaust mechanism, the combination with an exhaust-column, 'of an adjustable exhaust-column bridge Within. said exhaust-column, said bridge comprising a plurality of sections normally tending to approach each other, substantially as and for the purposes specilied.

9. In a variable-exhaust mechanism, the combination with an exhaust-column, of an exhaust-column bridge Within said exhaustcolumn, said bridge comprising a plurality of relatively movable sections, and means for moving said sections relatively, substantially as and for thepurposes specified.

10. In a variable-exhaust mechanism, theA combination with an exhaust-column, of an exhaust-column bridge Within said exhaustcolumn, said bridge comprising a plurality of relatively movable sections, and a cam for moving said sections relatively, substantially as and for the purposes specified.

11.v In a variable-exhaust mechanism, the

combination with an exhaust-column, of an exhaust-column bridge Within said exhaustcolumn, said bridge comprising a plural-ity of relatively movable resilient sections, and means formoving said sections relatively, substantially as and for the purposes specified.

12. In a variable-exhaust mechanism, the` combination with an exhaust-column, of an exhaust-column bridge within said exhaustcolu mn, said bridge comprising a plurality of. relatively movable resilientsections, and a cam for moving said sections relatively, sub.- stantially as and for the purposes specified.

lf3. In a variable-exhaust mechanism," the combination with an exhaust-column having` BEST AVAlLABLE COF` a choke, of means Within said exhaust-columi for varying the exhaust area of said exhaust column at the choke, substantially as and fo: the purposes specified.

14C. In an exhaust mechanism, the combina tion with an exhaust-column havingupwardly convcrgingwalls, of an exhaust-columnbridge within said exhaust-column, said bridge having upwardly-divergi ng walls, substantially as and for the purposes specified.

15. In an exhaust mechanism, the combinaupwardly-converging walls, a choke and di- Verging walls above said choke, of an adjustable .exhaust-column bridge comprising a plurality of resilient sections terminating adjacent to said choke, substantially as and for the purposes specified.

18. In a. variable-exhaust mechanism, the combination with anv exhaust-column having .upwardly-converging walls, a choke and di verging Walls above saidv choke, of an' adjustf able exhaust-column bridge comprising a plu- .rality of resilientsections terminating adjacent to said choke,\andv a cam adapted to actuate said resilient sections, substantially as and for the purposes specilied. a. 19. In a variable-exhaust mechanism, the

- combination With an exhaust-column. having upwardly-'converging Walls, a choke land divergingwalls above said choke, of an adjustable exhaust-column bridge comprising a plurality of relatively movable sections terminating adjacent to said choke, and means for movingsaid sections relatively, substantially as and for the purposes specified.

20. In a variable-exhaust mechanism, the combination With an exhaust-column, of i an exhaust-columnl bridge within said exhaustcolumn, said bridge comprising a4 plurality of relatively movableY sections, and means for automatically moving said sectionsrelatiwly, substantially asand for the purposes specified. 21. In a variable-exhaust mechanism, the combination with an exhaust-column, of an exhaust-column,bridge within said exhaustcolumn, said bridge comprising a plurality of Arelatively movable resilient sections, and

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22. In avariable-exhaust mechanism, the )mbination with an exhaust-column, of an xhaust-column bridge within said exhaustolumn, said bridge adapted to vary the exaust area of said exhaust-column, and means or automatically actuating said exhaust-colmn bridge to vary said exhaust area, subtantially as and for the purposes specified.

23. In a variable-exhaust mechanism, the ombination with an exhaust-column, of an :xhaust-column bridge within said exhaustzolumn, said bridge adapted to vary the exiaust arca of said exhaust-column, a cylinder, t piston within said cylinder, means for automatically actuating said piston, and devices interposed between said piston and said exhaust-column bridge for actuating the latter, substantially as and for the purposes specified.

24. In a variable-exhaust mechanism, the

combination with an exhaust-column, of an adjustable exhaust-column bridge within said exhaust-column, a cylinder, a piston within said cylinder, pressure-controlled means for actuating said piston, means for limiting the length of ystroke of said piston, and devices interposed between said piston and said ex haust-column bridge for actuating the latter, substantially as and for the purposes specified.

25. In a variable-exhaust mechanism, the combination with an exhaust-column, of an adjustable exhaust-column bridge within said exhaust-column, a cylinder, a piston within said cylinder, a high-pressure valve controlling a cylinder-port, a low-pressure valve controlling a cylinder-port, a diaphragm` acting upon said high-pressure valve, a diaphragm acting upon said low pressure valve. and means interposed between said piston and said "ei'ustcolumn bridge for actuating the latter, `substantially as and for the purposes specified.

26. In a variable-exhaust mechanism, the combination with an exhaust-column, of an adjustable exhaust-column bridge Within said exhaust-column, a cylinder, a piston within said cylinder, a high-pressure valve controlling a cylinder-port, a low-pressure valve controlling a cylinder-port, and means interposed between said piston and said exhaust-column bridge for actuatingthe latter, substantially as and for the purposes specilied. y

27. In a variable-exhaust mechanism, the combination with an exhaust-column, of an adjustable exhaust-column bridge within said exhaust-column, a cylinder, a piston within sail "ylinder, a high-pressure valve controllinga cylinder-port, a low-pressure valve controlling a cylinder-port, springs acting upon said valves, and means interposed between said piston and said exhaust-column bridge for actuating the latter, substantially as and for the purposes specified.

28.In a variable-exhaust mechanism, the combination with an exhaust-column, of an BEST AVAILABLE COF" adjustable exhaust-column bridge comprising a plurality ot' relatively movable Vsections within saidexhaust-column, a cam interposed between said sections and adapted to actuate the same, acrank adapted to actuate said cam, acylinder, apiston within said cylinder, means for automatically actuating said piston, and a reach-rod flexibly connected to said crank and said piston, substantially as and for the purposes speciied.

29. Ina variable-exhaust mechanism, the` vcombination with an exhaust-column, of an adjustable exhaust-column bridge comprising a plurality oi' relatively movable sections within said exhaust-column, a cam interposed between said sections and adapted to actuate the same, a cylinder, a piston within said cylinder, means forlimiting the stroke of said piston, means for automatically actuating said piston, and devices interposed between said piston and said cam for actuating the latter, substantially as and for the purposes specified.

30. In a variable-exhaust mechanism, the combination with an exhaust-column, of an adjustable exhaust-column bridge comprising aplurality of relati vcly movable sections within said eXhaust-cplumn, a cam interposed between said sections and ad apted to actuate the same, a crank adapted to actuate said cam, a cylinder. a movable member within said cylindex', a high-pressure valve controlling acylinder-port, a low-pressure valve controlling a cylinder-port, diaphragme for said valves, springs acting upon said diaphragms, means for graduating the pressure of said springs upon their respective diaphragms, and means interposed between said movable member and said cam for actuating' the latter, substantially as and for the purposes specitied.

31. In -a variable-exhaust mechanism, the combination with an exhaust-column, of an adjustable exhaust-column bridge comprising a plurality of relatively movable sections within said exhaust-column, a cylinder, a piston within said cylinder, a high-pressure valve controlling a cylinder-port, a low-pressure valve controlling a cylinder-port, diaphragms for said valves, means for transmitting pressure to said diaphragms, and means interposed between said piston and said exhaust-column bridge for actuating the latter, substantially as and for the purposes specified.

32. In a variable-exhaust mechanism, the combination with an exhaust-column, ot' an adjustable exhaust-column bridge within said exhaust-column, a cylinder, a piston within said cylinder, a high-pressure valve controlling a cylinder-port, a low-pressure valve coutrolling a cylinder-port, diaphragms for said Valves, springs acting upon said diaphragme, ln'eans Vfor grai'lllating' the pressure of said springs upon their respective diaiiihragms, means for transmitting pressure to said diaphragms, and devices interposed between said IOO IIO

IIS

sEsT AVAILABLE cee` piston and said exhaust-column bridge for actuating the latter, substantially as and for the purposes specified. l

33. In La variable-exhaust mechanism, the combination with an exhaust-column, of an adjustable exhaust-column bridge comprising a plurality of resilient. sections Within said eX- haust-column, a cylinder, a piston Within said cylinder, means for automatically actuating said piston, and means interposed betweensaid piston and said exhaust-column bridge for actuating the latter, substantially as and for the purposes specified.

34. In a variable-exhaust mechanism, the combination with a draft-regulator, of a high and low pressure cylinder, and independent high and low pressure valves operative to control the admission ofpressure to the said cylinder, substantially as and for the purposes specified. l

35. In a variable-exhaust mechanism, the combination with an exhaust-column, of an adjustable exhaust-column bridge, a high and low pressure cylinder, independent high and low pressure valves operative to control the ad mission of pressure to the said'cylinder, and means operative by the. admission of pressure to the cylinder for actuating said adjustable bridge, substantially as and for the purposes speciied.

36. In a variable-exhaust mechanism, the combination with an exhaust-column, of an adjustable exhaust-column bridge, a source of pressure, and means operated by variations in said pressure for actuating said exhaustcolumn bridge, substantially as and for the purposes specified.

37. In a variable-exhaust mechanism, the combination with an exhaust-column, of an ad justable exhaust-column bridge, a cylinder, a source of pressure connected to said cylinder, and means actuated by variations in said pressure for operating said exhaust-column bridge, substantially as and for the purposes specified.

38. In a variable-exhaust mechanism, the

40. In a variable-exhaust mechanism, the

combination with an exhaust-column, of an adjustable exhaust-column bridge having a closure for the top thereof, and means for adjusting said exhaust-column bridge, substantially as and for the purposes specified.

41. In a variable-exhaust mechanism, the combination with an exhaustcolumn, of an exhaust-column bridge comprising a plurality of relatively movable sections having their upper ends engaging each other to form a closure for the top of said exhaust-column bridge, substantially as and for the purposes specified.

, 42. In a variable-exhaust mechanism, the combination with an exhaust-column, of an exhaust-column bridge comprising a plurality of resilient sections having their upper ends 'bent inwardly to form a closure for the top of said exhaust-column bridge, substantially as Aand for the purposes specified.

43. An exhaust-column bridge comprising v a plurality of resilient sections provided with y CHARLES L. PAGENHART.

Witnesses:

OTIS ELLIsoN, H. C. CARROLL.

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