US245774A - Steam-engine - Google Patents

Description

(No Model.) 2 Sheets-Sheet 1.

B. BRAZELLE STEAM ENGINE. No. 245,774. Patented Aug. 16,1881.

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2 Sheets--Sheet 2.

(No Model.)

B. BRAZBLLE,

STEAM ENGINE.

No.- 245,774. PatentedA ug. 16,1881;

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'UNITED, STATES- PATENT QFEICE.

BENJAMIN BRAZELLE, OF ST. LOUIS, MISSOURI.

STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 245,774, dated August 16, 1881.

Applicationfiled May 7,1881. (No model.)

To all whom it may concern Be it known that I, BENJAMIN BRAZE IIE,

of St. Louis, in the county of St. Louis and State of Missouri, have invented certain new and useful Improvements in Steam-Engines, of which improvements the following is a specification.

The object of my invention is to provide an engine in which theexpansive action of steam can be advantageously and economically exerted without the/necessity of employing more than a single cylinder, and without the use of the more or less complicated and expensive valve mechanisms heretofore required for the purpose. y 1,

To this end my improvements consist in a distribution-valve having internal expansionchambers, and in the combination of a valve so formed with a cylinder and steam-chest.

Myimprovements further consist in the combination of a distribution-valve having internal expansion-chambers and adjustable cutoff plates, by which the quantity of steam supplied to the chambers can be varied, either automatically or by hand, in accordance with the desired grade of expansion or fraction of the stroke of the piston at which steam is to be cut off.

The improvements claimed are hereinafter more fully set forth.

In the accompanying drawings, Figure 1 is a vertical longitudinal central section through the cylinder and steam-chest of an engine, showing the application of my improvements as adapted to afixed grade of expansion; Fig. 2, a vertical transverse section through the same at the linear w of Fig. 1; Fig. 3, a vertical longitudinal central section through a cylinder and steam-chest, showing my improvements as adapted for variable expansion; and Fig. 4 a plan or top view of the same.

In the practice of my invention, which is equally applicable to single-cylinder and to coupled engines, the cylinder A is of the ordinary construction, provided wit-l1 induction and exhaust passages c a, to and from which steam is supplied and exhausted by a sliding or oscillating distribution-valve, a long and a short D-slide valve respectively being herein shown and described as illustrating the most simple adaptation of my improvements to existing practice.

Referring to Figs. 1 and 2, the distributionvalve B is of the long D-slide type, provided with the usual exhaust-recesses in its face, and is reciprocated within the steam-chest B by the valve-stem B being in so far similar to the ordinary valve. Above its working-face I form on the valve B, by webs of metal of suitable thickness, two expan sion-chambers, B B, one adjacentto each end of the valve, and

each having a port, I), on its lower side, the outer opening of which port is in line with the working-face of the valve, so that according to the relative positions assumed by the valve in its traverse the steam which is supplied to the chest B by the steam-pipe B will, alternately, first enter and fill the expansion-chambers through their ports I), and subsequently escape therefrom through said ports and the induction-passages a, and exert its pressure in the cylinder A upon the piston A. The steam is exhausted from the cylinder and escapes through the exhaust-pipe B in theordinary manner. The piston A in Fig. 1, which is shown as moving to the right, is actuated by the steam from the expansion-chamber B on the left, which steam has been supplied to the chamber during the preceding stroke, and dur- .the ratio of the volume of one of the expansion-chambers to th at of the cylinder,the quantity of steam supplied to each chamber, and no more, being that which is admitted behind the adjacent side of the piston at each stroke in the opposite direction, and the engine therefore works at such fixed grade of expansion as may be determined by the constructer.

Inasmuch as the capacity of varying the grade of expansion, in conformity with variations in imposed duty, is an important desideratum in numerous instances, I provide for such purpose the means illustrated in Figs. 3 and 4. The expansion-chambers B and delivery-ports b, through which the steam passes a 245mm ,per wall of each chamber, adjacent to its outer end, the outer surfaces of said walls being finished truly at and adjacent to said supplyports, so as to form working-faces. An adjustable cutoff plate, 0, faced truly on its under side,rests upon the top of thevalveB, above the supply-ports b, said plates being connected by links to arms 0 on the lower end of an adjusting-shaft, C, which passes through the steam-chest cover, and has a crank-arm, 0 secured to its outer end. By the movements, in one or the other direction, of a rod, 0 journaled to the end of the arm 0 the cut-0E plates may be drawn together or moved apart, and will correspondingly increase or decrease the duration of opening of the supply-ports I) in the valve which moves beneath them, and therebyadmita greater orless amount of steam to the chambers at each stroke.

The rod 0 may either be connected to a hand-lever and indicating-segment, where the point of cut-off is to be varied by the engineer, as in locomotive and marine engines, or may be actuated by the governor where automatic regulation is required. It will be obvious that, as in the former instance, the initial grade of expansion is determined by the relative volumes of the expansion-chamber and of the cylinder, and any desired higher grade or shorter point of cut-off can be obtained to the extent of shutting off steam entirely by adjustments of the cut-off plates, which adjustments can be effected during the motion as during the rest of the engine. By the provision of chambers of sufficient capacity the engine may be started under a load so as to work following full stroke, and the point of cut-oft be varied gradually or instantaneously in desired conformity with the variations of resistance.

By my improvements an expansively-workingengine of very simple construction is pro- Vided, a single cylinder and distribution-valve afiording the advantage of employing high initial pressure and economical expansion to the desired terminal, which result has heretofore been attained only in automatic and compound engines,the complication and expense of which is so great as to render them undesirable for many classes of service.

I am aware that hollow or box-slide distribution-valves having an internal chamber or chambers through which steam passes to and from the cylinder are not new, and do not, therefore, broadly claim a valve of such construction. So far, however, as my knowledge and information extends, the purpose and function of said valves has been to partially relieve or balance the pressure of steam upon their external surfaces, and none of them, so far as I am aware, were designed for or are capable of supplying a measured volume of steam to the cylinder at each stroke, as in my hereinbefore-described invention.

I claim as myinvention and desire to secure by Letters Patent 1. A distrilmtion-valve for steam-engines, having an internal expansion-chamber and a port therein, by which said chamber is caused to communicate alternately with the steamchest and with the cylinder, substantially as set forth.

2. In a steam-engine, the combination, substantially as set forth, of a cylinder, a steamchest, and a distribution-valve having an internal expansion-chamber and a port therein, said chamber and port forming the avenue of communication through which a determined volume of steam is supplied to the cylinder at each stroke of the piston.

3. In a steam-engine, the combination, substantially as set forth, of a distribution-valve having internal expansion-chambers, deliveryports in said chambers adapted to communicate with the cylinder, supply-ports adapted to communicate with the steam-chest, and adjustable cut-off plates by which a greater or less quantity of steam may be admitted to the supply-ports of the expansion-chambers at each stroke of the valve.

4. The combination of a chambered distribution-valve having delivery-ports upon its face adjacent to the cylinder, and supply-ports upon its opposite face, movable cut oft plates fitting freely upon said opposite face, links by which said plates are coupled to arms upon an adjusting-shaft, and a rod by which said adjusting-shaft may be coupled to hand or automatic regulating mechanism.

B. BRAZELLE.

Witnesses:

J. SNowDEN BELL, CHAS. A. SAFFORD.

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