US62713A - Improvement in steam engines - Google Patents

Description

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@geiten gieten atmft GEORGE I. WASHURN, VOF `lllfOlitCfE STE-R, MASSACHUSETTS.

Letters Patent No. 62,713, dated VIarcL 5,4 1867.

IMPROVEMENT IN STEAM ENGINES.

TO ALL WHOM IT MAY CONCERN:'

Be it known that I, GEORGE I. WASHB'UBN, of the city and county of Worcester, and State of Massachusetts. have invented a new and useful Improvement in Steam Engines; and I do hereby declare the following to be a full, clear, and exact description of the same, suiicie'nt t0 enable one skilled in the art to which the invention appcrtains to make use of it, reference heilig had to the accompanying drawings, which form apart of this specilication, and in whieh i Figure I is a'vertical section on' the line :r at, fig.'

Figure 2 is a vertical section Von thelinc y y, fig. 1.

. Figure 3 is a horizontal section un the line z z, iig. 1. Figures 4, 5, and 6 show the same application of steamfto an engine in which the pistons are annular, have two piston-rods, and the rod connecting the cross-head with the crank passes through the centre of the cylinder.

This engine has two double-acting pistons, each operating by itself-in its'steam cylinder, and attached to a pistou-rod which carries a valve of any suitable construction, operating in its own chamber. Each valve controls the action of the steam upon the double-acting piston in the opposite cylinder, and not that piston to which Ait is attached. A`valve upon the eduction port, or in the exhausty pipe, opening outwardly, closes lthe aperture against the reflux of exhaust steam. The piston-rods may be attached each to its own crank on a double crank-shaft, as in the drawings, or may both be attached to the same crank, provided that in all cases they are so located in reference te each other that, when one piston is at the end of its stroke, the valve governing the action of steam thereupon may be in the proper position for reversing thesaid motion. Thus, if the cylinders are placed parallel to each other, as in the drawings, it will be necessary to have adouble crankshaft in order tomaintain the above relation between the valve and piston, `but if-the .cylinders are placed in the saine-plane, and at an angle of ninety degrees with each other, the rods may be attached to thc same crank, and a proper valve motion preserved.` In the first-mentioned instance a benefit will result from shortening the steam passages, and in the'sccond I use but one crank. An angle of ninety degrees is found between the two cranks or the two cylinders. If the two cylinders be placed at an angleof ninety degrces'aiid both pistone operate upon a single crank, the pipes which convey the steam from thc valves to the pistons may be flexible or jointed, each cylinder hanging upon trn-nnions,-and dispensing with cross-head ways and connecti'ng-rods. The two piston-rods may be attached directly to the crank, the valve action remaining the same as before. The steam may be taken either through flexible orjointed pipe, or through thehollow trunnions; and exhaustedliliewise. Also the connecting pipes may be enclosed 'in a chamber and heate'd by any suitable means, as steam, or the product-s of combustion as they pass from the boiler to prevent condensation of steam in the connecting passages. In this fom the enginewill have two oscillating cylinders, but the mutual action of the valves and pistons is designed to be the same as in the drawings, when the cylinders are stationary Aand parallel, the valve on a given piston-rod controlling the action of the steam on the piston of the other rod.

While I do not confine myself to a disk-valve, it is n necessary feature of my invention that the valve shall be attached to the piston-rod and more with the piston to which it is attached, though its effective action is upon the other piston in the other cylinder.y The valve-chamber and piston-chamber, ltraversed by a common piston-rod, are separated by a cylinder head, which entirely divides them so -far as any association of coaction is concerned, the valve action, though, isochronous with the piston niotior, having no immediate effect upon it. I donot rely upon any extraneous condenser for obtaining a partial vacuum before the piston, but afford the exhaust steam the means of escaping with the maximum liberty and freedom, and provide a check-.valve over the ports in the exhaust-chamber to admit the cfiiux but prevent the reflux of steam therethrough.

The steam as it rushes ont will drive the atmosphere before it=until its momentum is overcome, at which time thc pressure behind it and against theexhaust side of the piston will be less than the atmospheric pressure outside, thereby obtaining a partial vacuum on the exhaustv side of the piston. The steam passing freely ont will expend' its momentum in driving the air before it through the' exhaust port, and, at the instant the momei tuuiis; expended, the minimum pressure upon the exhaust side of the piston is attained. This check-valve on the exhaust port, or iii the exhanstpipe, is not designed to constitute the space intervening between it and the ci; is 2 cylinder as acondenser-in any respect or degree, but to prevent the reflux of the exhaust steam into the cylinder. The automatic check-valve thus placed in the exhaus'passage o1: on the exhaust port is opened by the ilow outward of the exhaust steam, and closed by the reflux of the same, or by its gravity,- or a spring, as soon as the force of the outgoing steam is insutlicient to keep it open.` It is not designed to prevent the escape of the steam, and is only operative when the exhaust port is open. lts object is to utilize the partial exhaust produced by the rapid emptying of the exhaaist end of the cylinder."'l`hat a partial vacuum is thus produced in certain contingencies is recognized by high expert authority, and it is areasonable deduction from the nature of the case.

In some cases, wherean engine has but a short stroke and rapid revolution of the crank, thc valve may not be necessary to make the moment-ary partial vacsium available, as the period during which the air and steam is held at hay preparatory to the reflux may be sufficient to enable the piston to complete its motion when the steam is reversed and thc exhaust-passage closed by mechanical means preparatory to the admission of live Steam to that side of the piston which was lateiyin Contact with the exhaust steam referred to. The rate of motion of the piston bei'n-gknown, and the rapidity with which the exhaust steam will pass from the cylinder being calculable,

it is reasonable to suppose that the speed of the steam being so far in excess ot' that of the piston which is following, a partial vacuum will, at a certain time, be formed before the'momentum of the outgoing exhaust steam is perfectly conterpoised by the resistance of the atmosphere. In some cases, as I havesaid, this period may be suicient for the purpose in short-stroke engines; but in others. which move more slowly, it is, or may b'e, useful to place upon the port or in the exhaust pipe avalre to prevent the redux, and make the partial vacuum thus pr duced more distinctly and certainly utilizable, and to prolong it for a longer period. To make this partial vacuum fully available, the port should be comp'aratively'large, and the pipe of such a shape as to offer theleast possible resistance to the passage of the steam, and also of such length that the steam may exert its momentum against the atmosphere before it leaves the pipe.

In' the drawings, A is one steam cylinder, and B a second cylinder, their axes being parallel in the drawings, but capable ofA other arrangement, as I have before stated. At the end of cylinder A is a valve-chamber, C, and at the end of cylinder B is a valve-chamber, D. Traversing longitudinally' in cylinder A and valvechamber. C is a piston-rod, a, having upon it a'piston, E, and valve-disks ee. Similarly the piston-rod b traverses in cylinder B and valve-chamber D, carrying the pistonl F and valvefdisksff. The cylinder and valve-chambers thus arranged in -line with each other, are separated by a. partition' or cylinder-head through a steam'tight opening, in which thepiston-rod passes. "Each piston-rod is connected byapitman and crank to the main shaft, on which is a ily-.wheel and two belt pulleys, as represented, the main s-haft being supported on standards, and the cross-head at each connection of piston-rod and pitman having guides, as usual under such conditions. G isthe induction pipe to the inductionchamber H, and I is the eduction pipe from the exhaust-chamber J, K being eheck-valves to prevent the reflux of exhaust steam back into the cylinder, as has been before4 referred to. Live steam from the boiler is constantly present in the vinduction-chamber H, and communicates by ports with the chamber C to the ou'ter faces of the disks e c', respectively, and communicates with chamberD by a single port, 3, between the two disks ff. 4The exhaust-chamber J' receives steam from chamber C through a single port, 6, between" the valves e e', and from chamberD',.through two p'orts, 8, above and below the disks .f.f, respectively. The cylinderA receives and ldischarges steam through the ports 10 and 11 alternately from chamber D, andthe cylinder B receives and discharges steam through ports 12v and 13, alternately, from chamber-C, the ports being alternately induction and eduction ports, and the pistons in each .case double-acting. Piston-rod a being down, and b athalf stroke descending, steam is admitted above disk 'c Afrom vchamber H, and passes through port 12 above piston F, the exhaust steam below .piston F passing out through port 13 to valve-chan'iber Glbetween disks@ e', and thence through port 6 t0 the' exhaust-chamber J. Steam admitted below disk e serves to balance its pressure on the valve in the' chamber C. While this is being eifected in cylinder B, steam is admitted from chamber H through port 3 into valve-chamber D, between the disks ff', and will pass thencethrough port 11 under piston E, as soon as the port 1l is uncovered by the disk f, passing its I nid stroke, the point' of. reversal ofithcsteam on piston E. As soon as this reversal occurs, the port 10 will be open for the exhaust steam from above piston E, to pass out into chamber D above disksf, and thence through port 8 into exhaust-chamber K. Theexhaust-chamber K connects by two ports with chamber D, and by one with chamber C, and the steam chamber connects by two ports with chamber c, and by one with chamber D. In each case the duplicate ports are respectively above and below the disks in the valve-chamber and the single port between the said disks., The steam admitted between the disks is thereby balanced in its action on them as a valve, and the same is true of the admission of it to the outer faces of the two disks on a given piston-rod. In lthe cylinders `it is admitted to the upper and lower faces alternately, and the reciprocating action thereby obtained.

The description having. been given at length of the action in one direction, the order and means for induction and eduction, while executing the return motion, will be readily understood by experts, to whom this specifica,- ton is addressed. The engine may be reversed by reversing the `functions of the steam and exhaust-chambers H J, except when using the check-valves K. The cylinders maybe vertical or horizontal, inclined or oscillatingthe connections thelrminimum lengtlu-asin the drawings, or longer if the cylinders are notso closely associated. Several may-.beasscciated around a common shaft with a common crank or cranks, H, disconnected, except as to their common shaft. Each valve, in the arrangement to lsecure the minimum length of ports, is opposite to the piston, whose motion it regulates, so that (as shown) the piston E is above the valve c e', and the piston E below the valve ff. Figs. 4, 5, and illustrate the same application of steam in an engine whose pistons are annular, having two piston-rods and the connecting-rods, which extend from the cross-heads to the crlanks passing through the centresoi` the cylinders. This admits of a certain compactness of arrangement not repdily attained in any other way. l y

Hrs-ving described my invention, what I claim therein ns new, end desire to secure by `Letters Patent, is as follows:

l. claini the nrralngement. upon one pistomrod, of the double-acting, operating piston in its own cylinder, and a. .valve oi' valves attached to said piston-rod, and operating Within a, valvecl1'amber iu line with said cylinder, substantially as described.

2. claim the combination with each otherof tivo such arrangements, (as expressed in the :rbove clnimJ tim valves attached to a given piston-rod ill-each case governingV the induction and eduction ports of the opposite steam cylinder, in which reciproca-tes the other piston-rod, substantially as described.

3.- I claim a valve, operating in connection with un exhaust port or pipe to permit the egress of steam, and

prevent reflux thereof, for the purpose described.

' GEO. I. WASHBURN.

Witnesses:

A.. D. HoBAR'r, EDWARD MELLE'N.

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