US62711A - Improvement in steam engines - Google Patents

Description

l@einen titties @anni @ffice GEORGE I.- I'VASHBURN, OF IVORGESTEH, MASSACHUSETTS.

.Letters Patent IVO. 62,711, dated Ilmcr, 1867.

IMPROVEMENT IN STEAM ENGINES.

@in rlgrhul nient it in tigre' tintas fjnttnt mit mating gnu nf tigtsamt,

'.lO ALL WHOM IT MAY CONGERN:

Bc it known that I, GEORGE I. WASIIDURN, of Worcester, in the 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 'oe a full, clear, andexact description of the same, suiiicient to enable one skilled in the art to which the Vinvention appertains to make use ot` it, reference being had Ato the accompanying drawings, which form a part of this specification, and in which- Figures I and 2 are central vertical sections, diil'erng in respect of the relative positions of the steam cylinders and in the arrangement of the valve, but agreeing in the moin feature of the invention, which is as follows: i i

The steam, after acting directly-upon one side ofthe piston in the smaller cylinder, is cutoff from the boiler, and allowed to iiow on both sides of the said piston, and expand against one side of the larger piston in the second cylinder.

By this arrangement the steam is used twice, and in connection with pistons in separate cylinders; the iirst time directly from the boiler, and the second time expansively; but when used upon thc second piston it is not allowed to exert a back pressure upon the irst piston, as is common in some engines which use the steam expansively in a second cylinder after using it directly in the first cylinder. In my improvement, after acting with full head, or directly upon the first piston, it is cut oil' and transferred to the second cylinder, flowing on y both sides of the first piston, so aste deprive it of any activerinduence as to that piston in the stroke made by the second piston. It may be out oil' at some time during the effective stroke of the first piston, and not employ a full head of steam to the conclusion of said stroke. This is an economical question, which doesl not ail'cct the point ot' my invention, which consists in transferring the steam, after the effective strokrl of the first piston, to both sides of the said piston, and to the second cylinder, where it acts expansivel'y, the communication with the boiler being cut oi. When the full head is used to the end ot' the strokeoi' the first piston no cut-oit action is required; but the valve closes the communication with the boiler at lthe same time that it opens the port leading from the irst to the second cylinder. The steam, by this arrangement, only acts effectively upon one side of' each piston, and upon the pistons consecutively, the steam, during the eii'ective stroke of the second piston, being balanced upon the respective sides of thefirst piston. A condenser may be attached to receive the steamA from abov'e the second riston; the atmosphere willthen assist inV making the return stroke ot' the latter while the direct action of the steam is making the effective stroke of the 'first piston. Steam is admitted above and below the valve either by making the valve hollow, so as to permit the iow of steam through it, (fig. 1,) or by opening the valve-chamber at each end to the steam, (fig. 2.)

In the drawings, A is the smaller cylinder, in which the steam directly from the boiler is admitted to the upper side of the piston B, which is `shown descending, the crank having described one-quarter ot' its downward stroke. C is the larger cylinder, in which thepiston D is ascending. The pistons B l) arc attached by means of their rods and pitmen to the cranks E F respectively, on the main shaft G, the cranks being opposite, as shown in'thediagram, iig. 1, a. The valve II is tubular, having two annular disks L h', one at each end, which tit the walls of the valve-chamber I, in which the valve reciprocates, as actuated by the eccentric J, on the main shaft Gr. K is the valve-rod, which is screwed into the upper end of the valve.

The operation is as follows: Steam is admitted by the pipe a to the valve-chamber I, and passing through the valve Il, enters cylinder A- through the port 5, and acts upon the upper side of the piston B until it has ,v/ reached ,the lower limit of its stroke, when the valve H is raised to the position shown in red lines, shutting the boiler steam from port l and exhaust port c, and opening the portb to the annular space around thc tubular valve, which space is bounded above andbelow by the disks L. Through this space the steam Hows to the port c, which opens into the upper end of the cylinder C, and acts expansively upon the upper side of the piston I), making the return stroke, and lifting lthe pistorrB. Here is seen the distinguishing peculiarity in the operation of luy invention, namely, as the steam flows fromthe space above the piston B in cylinder A through the port I), and around the valve to the port c, to the larger cylinder, it also flows through the p'ort d underneath the piston E in cylinder A, so that no resistance' is made 'by steam to the raising of the said piston, as the stcalmhcing admitted above and below, balanced in its action on the said piston, so that no back press- -ure is exerted upon the first pistonA while the steam is used expansively on the second. Bythe means described the piston B having arrived at the upper limit of its stroke, and the piston D at its lower limit, the valvel is again depressed, assuming the position shown in dark lines in the figure, when the steam is admitted as before, they exhaust steam passing out of each cylinder by the ports nl c respectively, and through the annular space around the valve, to the exhaust pipe e. As has been' observed, the upward motion of the piston D, andthe downward motion of piston B, maybe assisted by a condenserconnected to the exhaust. The air is admitted I to the lower si'de of piston D through opening f. If any cut-otf action is required in the use of the steam in the downward stroke of piston B, it is obtained by the adaptation of the eccentric to that duty in a mannervfamiliar to experts. The'downward motion' of piston D is entirely due to the expansion of the body of steam admitted' to cylinder A, to perform its duty ou piston B after the said body of steam is cut oil' from the boiler. Fig. 2 shows the two cylinders, placed one above the other, the port (Z being dispensed with, and the piston D being i connected to the shaft G by two piston-rodsY and two cranks F F. The action of the .steam is the same in this arrangement'as in the other,'illustrated in fig. 1, the steam from the boiler being admitted through ports a and b to the upper face of the pistou B in cylinder, andl expanded from thence as the change of position of the valve occurs, through the port c, to the upper face of piston D in the enlarged lower cylinder C, at the same-time bearing against the under side of piston B, and balancing the pressure exerted against its upper side. lt will be observed that the valve in fig. 2 consists of two disks on a valve-rod, and that it dilfers from the valve H shown in fig. 1, the latter being tubular. The two disks agree in all respects with the disks on valve H, as boiler steam is constantly present on their respective outer surfaces, and the space between them is alternately a means of communication between the two -cylinders and between the cylinders and the exhaust port c; the extra pipe a isa steam pipe, introducing steam below disk L so as to balance the pressureiupon the upper disk L. It isoil course possible to arrange two similar engin-es in relation to one crank so that one should be upon its dead centre while 'the other was at mid stroke.

Having described my invention, what I claim therein as new, and desire to secure by Letters Patent, is

Au arrangement of cylinders and steam ports,`by which the steam, after being used on one piston, is permitted toilow to the other side of the same piston and to the other cylinder, to be used oxpansively, substantially as described. A

I claim the arrangement of the double disk hollow'valve H, operating substantially as described.

GEO. I. WASHBURN.

Witnesses:

SA l). Mouse, EDWARD hInLLEN.

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