US716382A - Steam-engine. - Google Patents

Description

NIL 716,382. Patented Dec. 23, |902.

W. S. CLWELL.

' STEAM ENGINE.

(Appumion mea oct. 29, 1901.) (No Model.) 2 Sheets-Sheet I.

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No. 716,382. Patented Dac. 23, |902.

' W. S. COLWELL.

STEAM ENGINE.

(ApplicatiQn'led Oct. 29, 1901.)

2 Sheets-Sheet `2.

(No Mdel.)

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WILLIAM S. COLVVELL, OF CHICAGO, ILLINOIS.

STEAM-ENGINE SPECIFICATION forming part 0f Letters Patent No. 716,382, dated December 23, 1902.

Application tiled October 29,1901. Serial No. 80,403. KNO model.)

*T0 1r/ZZ whom ir may concern:

Be it known that I, WILLIAM S. CoLwnLL, residing at Chicago, county of Cook, and State of Illinois, have invented a certain new and useful Improvement in Steam Engines, of which the following is a specification.

My invention relates to steam-engines of the direct-acting or reciprocating type, and more particularly to engines of this type which employ a vacuum for decreasing the pressure necessary for driving the piston, and which for this reason are ordinarily known as low-pressure engines.

Generally stated, the object of my invention is to provide certain details and features of improvement which will tend to increase the efiiciency of alow-pressure steam-engine. Certain special objects are to provide a simple and effective form of valve mechanism for controlling the exhaust and to arrange and operate the same in such manner that the condensing or vacuum-producing means will not receive the entire exhaust, but will only receive such portion of the exhauststeam as may remain in the cylinder after a momentary discharge or exhaust into the atmosphere, it being a particular and special object of the invention to provide a valve device for this purpose which may be readily and conveniently attached to any of the wellknown or approved constructions of steamengine now in use.

To the foregoing and other useful ends the engine can be of any suitable form or construction and the condenseror vacuum-producing means can be of any suitable form and arranged to connect with the cylinder of the engine in any known or approved manner. The valve mechanism, however, is of such character that in exhausting` the discharge is first into the atmosphere and then into the passages leading to the condenser or apparatus for producing the vacuum. In other Words, the arrangement is such that when the pistou has, for example, completed its forward stroke the exhaust-steam is then allowed to escape into the atmosphere, and when the piston starts on its return stroke the exhaust into the atmosphere is then cut oft and the valve mechanism shifted in such manner as to establish communication between the cylinder and the vacuum-chamber.

In this way the condenser or vacuum-chamber does not receive the entire exhaust, but only such portion of the exhaust as may remain in the cylinder after the initial and momentary discharge of the same into the atmosphere. This arrangement and method ot' operation permits the vacuum to act on the advance side of the piston in the usual manner and enables the piston to advance under reduced steampressure, as is the casein steam-engines of the low-pressure type. It Will be seen, however, that with the initial or momentary exhaust into the atmosphere the vacuum-chamber is thereby relieved of the necessity of condensing or reducing the entire volume of the ex' haust to Water in order to produce the desired vacuum for reducing the pressure on the advance side of the piston. In this way the etticiency of the engine is greatly increased, inasmuch as less power and energy are employed and utilized in producing the Vacuum and for the further reason that the arrangement obviates the necessity of providing extensive condensing and pumping apparatus for condensing the exhaust and returning it to the boiler. In order that my invention may be made applicable to any of the well-known or approved constructions ot' steam-engine, the means for controlling the exhaust in this manner can bein the nature of asupplemental valve device adapted to be attached to the usual exhaust or discharge opening of the engine-cylinder. This supplemental valve device can be operated in any suitable or desired manner-as, for example, by connecting it with the eccentric-strap, which is usually employed for operating the valves which control the admission and exhaust. The invention thus embodied in the form of an attachment can, as stated, be convenientlyapplied to any known or approved constructionA of engine, and it cau be readily attached Without necessitating any changes in the engine. The nature and operation ot' my invention, together with other advantages,will,however, hereinafter more fully appear.

In the accompanying drawings, Figure l is a side elevation of a low-pressure steam-engine embodying the princigles of my invention. Fig. 2 is an enlarged side elevation of the eccentric and means for operating the valve mechanism. Fig. 3 is an end elevation IOC of the valve which is employed for controlling the exhaust and which is arranged to rst direct the exhaust into the atmosphere and to then cut o" such exhaust and establish communication between the cylinder and the vacuum-chamber, it being observed that the valve device thus shown is in the nature of an attachment adapted for use-in connection with any known or approved construction of steam-engine. Fig. 4 is a side elevation of the valve device shown in Fig. 3. Fig. 5 is a longitudinal section on the line 5 A5 of Fig. 3. Fig. 6 is a cross-section online 6 6 in Fig. 4. Fig. 7 is a detail side elevation of the rotary valve inclosed by the casing shown in Figs. 3 and 4. Fig. 8 is a cross-section on line 8 8 in Fig. 7. Fig. 9 is an end elevation of the valve shown in Fig. '7. Figs. l0, ll, l2, 13, and 14 are diagrammatic views illustrating the operation of the valves for controlling the admission and exhaust and showing the manner in which the supplemental valve first directs the exhaust into the atmosphere and then operates to establish communication between the interior of the cylinder and the vacuum-chamber.

It will be understood that the engine shown in Fig. l can be of any known or approved construction and that the construction may involve the usual cylinder A, the balancewheel B, and also suitable connnection between the shaft b and the piston, which, it will be understood, is inclosed within the said cylinder. In the construction shown the piston-rod a is connected with the crank-shaft by means of a pitman at@ The reciprocation of the piston operates to rotate the crankshaft in the usual manner, and the latter is provided with an eccentric-cam-C, adapted and arranged to operate the valve-rods c and c. These valve-rods can be arranged to operate the admission and exhaust valves of the engine in any suitable manner-'as, for example, by connecting the rod c with a rotary disk or plate c2, which is in turn connected with the valves by means of short rods or pitmen c3. y The rotation of the eccentric-cam operates to oscillate this plate c2 through the medium of the valve-rods, and the oscillation of this plate causes the valves to shift or rock, so as to open and close the ports for supplying the steam and discharging the exhaust. The live steam can be supplied to the admission-valves through a valve-pipe l, and the exhaust can be discharged from the bottom of the cylinder at 2. The said valves can be of any suitable or desired form, my invention, as stated, being applicable to any of the known constructions and to such engines as may be already built and in use.

The supplemental valve device (shown in Figs. 3 to 9, inclusive) is adapted to be applied to a steam-engine-such, for example, as the one shown in Fig. l-and, as previously explained, is adapted to coperate with a condenser or vacuum-chamber in subjecting the advance side of the piston to vacuous action. To such end this supplemental valve device may comprise a suitable body orl casing D, constructed with an upper port or opening d, adapted to register with the exhaustopening of the cylinder and also provided with three discharge-openings d d2 d3. The ends of the body or casing can be provided with suitable heads d4 and d5, the latter being preferably so constructed as to providea stuffing-box d?. The rotar)T Valve member D' is preferably cylindric in form and adapted to fit the bore of the body or casing D. This valve member is preferably and desirably formed with a slot or transverse opening d7, preferably enlarged or widened at its upper portion, so as to always be in communication with the opening d, and narrowed at its lower portion, so as to permit it to register with any one of the openings d' d2 d3. The means for rotating this valve member consists, preferably, of a rod D2, provided with a crank-arm d8. This rod,it will be observed,is arranged to extend through the stuffing-box d and is provided at its inner end with a bar or cross-piece (Z9, adapted to engage a groove or recess d10 in the end of therotary valve member D. With this arrangement said valve member can be oscillated or partially rotated in its casin g by swin ging the crank-arm d8 one way or the other, according to the'direction in which it is desired to turn the valve in order to establish communication between the opening d and any one of the lower openings d d2 d3. As explained, the casing or body of this valve device is adapted to be secured to the cylinder of an ordinary engine and to have its opening d register with the usual discharge or exhaust opening in the side of the cylinder-casing. In Fig. l this supplemental Valve device is shown in place on the under side of the cylinder A. The axis of the valve member D is preferably at right angles to the axis of the cylinder to which it is applied. `With this arrangement the supplemental valve device can be operated from the usual eccentric on the crankshaft of the' engine. For example, as shown in Fig. l, the crank-arm d8 is connected with a lever-arm E by means of a rod or pitman e. This lever-arm is preferably pivoted to some portion of the engine structure and has its upper arm connected with the eccentricstrap through the medium of a rod or pitman e. With this arrangement the rotation of the eccentric-cam C will cause the lever-arm E to vibrate, and thereby reciprocate the rod e in such manner as to rock or partially rotate the valve member D'. In other words, the engine in operating in the usual manner causes the supplemental valve device to control the exhaust and to direct the latter either into the atmosphere or into the passages leading into the condenser or vacuum-chamber. This condenser or vacuum-chamber can be of any suitable or approved construction and can be arranged and connected up with the ports oropenings dl and d3 inV any suitable IOO IIO

or desired manner. In Fig. 14 of the drawings this condenser or vacuum-chamber F is indicated in dotted lines and is shown as having suitable pipe connections with the two ports or openings CL and cl3.

The operation of an exigirle thus equipped with my improved exhaust-controlling attachment is as follows: Iu Fig. 10 the piston is shown at the extreme limit of its stroke to the right, and the supplemental valve is therefore in position to direct the exhaust from the left of the piston into the atmosphere through port d?. It will be understood that the valves 3, i, 5, and 6 shown in this view and also in the succeeding views are the valves for controlling the admission and exhaust and that the same can, as previously explained, be operated and constructed in any suitable manner. The valve at this juncture being positioned as shown in said Fig. l0, the exhaust-steam at the left of the piston, as stated, escapes into the atmosphere, and the cran k-shaft then continuing to rotate the piston starts on its return stroke to the left, as shown in Fig. 1l. It will be seen at this point, however, that the supplemental valve has shifted to an extent to establish communication between the interior of the cylinder and the port or opening d. This adjustment of the valve permits the residue or remaining portion of the exhaust to pass from the cylinder into the vacuumchamber F. (Shown in Fig. la.) In this way a vacuum is immediately induced in the cylinder ahead of the piston, and the latter then travels to the left under the iniiuence of the vacuum on its advance surface and steam-pressure on its rear surface. This, it will be seen, reduces the pressure necessary for propelling the piston forward, inasmuch as the vacuum ahead of the piston is fully as eective as the steam in producing the forward movement of the piston. It will be seen, however, that by thus initially exhausting into the atmosphere the condenser or vacuum-chamber is relieved from the necessity of receiving the entire volume of the exhaust and of condensing and reducing the saine to Water. In other words, the arrangement secures all the advantages of a vacuum in operating the pislton and at the same time obviates the necessity of condensing the entire volume of the exhaust. As previously explained, however, the vacuum-chamber F can be equipped with any suitable condensing means, so as to insure the proper condensing ofthe residue or remaining portion of the exhaust. In Fig. 12 the piston is nearly at the end of its stroke to the left, and in Fig. 13 the piston has started on its return stroke to the right. lVhen the piston has arrived at the end of its stroke to the left, the operation is substantially the same as in Fig. l0, the exhaust being first discharged through the supplemental valve into the atmosphere through the dischargeopening cl2 and then cut oi and directed through the exhaust-passage d3 into the pipe or conductor leading to the vacuum-chamber F. In Fig. 14 the piston has nearly reached the limit of its stroke to the right, and the supplemental Valve is just moving into position to permit the initial exhaust from the cylinder into the atmosphere in the manner shown in Fig. 10.

Thus it will be seen that I provide an improved valve arrangement for controlling the exhaust from a steam-engine of any known or approved construction and which operates in such manner as to greatly increase the efficiency of the engine. As previously stated, the initial exhaust into the atmosphere and the subsequent establishment of a vacuum in the cylinder secure all the advantages ofthe low-pressure principle and at the same time obviate the necessity of providing extensive condensing and pumping apparatus for condensing the exhaust-steam and returning it to the boiler. The vacuous action which I obtain with myimproved valve arrangement is fully as eiective in decreasing the steam-pressure necessary for propelling the piston as the usual or ordinary arrangement, in which the entire volume of the exhaust is condensed in the vacuum-chamber and reduced to water for the boiler. Furthermore, it Will be seen that I embody my invention in the form of a supplemental valve which may be readily and conveniently attached to any of the Well-known and approved constructions of engine. In this way my invention can be applied as an attachment to any engine, so as to convert the latter into a low-pressure engine operating in the described manner and having as a result higher efficiency than low-pressure engines operating in the ordinary Way.

What I claim as my invention isl. The combination with a direct-acting engine havinga reciprocating piston, and apistonv-cylinder provided with valved ports for supply and exhaust; of a vacuum-chamber; an attachment to the piston-cylindercomprising a shell or casing haviuga port connected with the main exhaust-port of the piston-cylinder and branched to form a couple of ports which are connected with the vacuum-chamber, and au intermediate port arranged for discharge into the atmosphere; a rotary three -way valve arranged for alternately opening and closing the branches of the port which connects with the main exhaust-passage, and operating during each stroke of the piston to Iirst'direct the exhaust from the mainl exhaust-passage into the atmosphere and to then cut offsuch exhaust and place the main exhaust-passage in open communication with the vacuum-chamber; and a valveactuating device applied for operating said rotary valve and comprising a crank connected with the valve, a reciprocating rod for actuating the crank, and connection arranged between the reciprocating rod and the eccentric-strap of the engine and involving a vibratory lever.

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2. The combination with a direct-acting engine having a reciprocating piston, and a piston-cylinder provided with valved ports for supply and exhaust; of ya vacuum-chamber; an attachment to the piston-cylinder having a port connected With the main-eXhaust-port of the piston-cylinder and branched `to form a couple of ports which are connected With the vacuum-chamber, and an intermediate port arranged to discharge into the atmosphere a rotary three-Way valve arranged for opening and closing the branches of the port which connects with the main exhaust-passage, and operating during each stroke of the piston to first direct the exhaust from the main exhaust-passage into the atmosphere and to then cut off such exhaust and place the main exhaust-passage in open communi- Witnesses:

ALEXANDER GRANT, WILLIAM E. ARMSTRONG.

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