US172603A - Improvement in balanced slide-valves - Google Patents

Description

Vcrate a plunger, D, which is top of, or to one Bn'NJM'uv BnAZEnLn, 1or sr. LoUiS, MISSOURI.

` ,',IMPRQl/ EMENT'IN BA-LANCED SLIDE-VALVES.

I v,Spieciicationforming partof Letters Patent To altwhom it amy-concem: i

,f Beit known that! I, BENJAMIN BRAZELLE, ofSt. Louis, vlVIissouri',.have invented Van ImprovedBalanc'ed Slide-Valve, of, which the following is a speeitication i This invention has for its object the relieving of slide-valves for steam-engines of friction, and achieves the advantageous-results from the use of a balanced slide-valve.

The constructive principle of this invention is based upon the obtaining of a perfect balance or equilibrium by means of unequal pressures acting upon unequal areas, and as now Will more fully appear.

Of the drawing, Figure 1 is a Sectional elevation on line a: m of Fig. 2. Fig. 2 is a top sectional plan on line w' w' of Fig. 1. Fig. 3 is a part side elevation, showing lever-connection with plunger-heads, Fig.4 4 being a bottom plan of slide-valve.

A represents the cylinder. B, Fig. 2, is the induction-port. b b1, Figs. l and 2, are the steam -inlet ports, which communicate by transverse ports b2 b3 to the valve-seat. b4 b5 are the main steam-ports, that serve alternately to admit steam to piston and exhaust from cylinder; B', Fig. 2, being the exhaustport. In steam-chest is the usual slide-valve C, having the three D-chambers or cores c c1 c2. The valve controls the ports b2 b3, and main ports b4 b5. rlhus, when valve is in the position as shown in Fig. 1, the core c covers the port b3, while the opposite core 0l covers ports b2 b4, establishing steam-connection to that end of cylinder, the center core c2 establishing exhaust-connection by covering port b5 and exhaust B', and vice versa when the reverse stroke of piston takes place.

To carry out the principle of lny invention as stated, Vconstituting the nature thereof, I provide a further port or communication, d, in conjunction with one of the inlet-ports-say, lil-(see dotted lines, Figs. l and 2,) the purpose of this port being to adlnit steam to opside of, the cylinder, as shown inl Figs. 1, 2, 3, the plunger D being to control the further admission of steam to steam-chest; hence the farther port d1, (shown is Fig. 1,) and communicating from plunger-cylinder to steam- N0.`172,603, datedJanuary 25, 1876; application filed July 26,1875.'

chest. The steam in the chest has a further communication by a port, d2, to the cylinder that contains the'plunger D'. (Shown clearly in Fig. 1.)

' By this means direct steam-connection from boiler is had to operate the plungers D D',

these being connectedby the lever E, as shown in Figs. 1 and 3. The leverage can be established or regulated by means of a movable fulcrum, E', which, as l1ere`shown,slides 011 a horizontal bar, e, Fign, although other ordi nary Ways ofchanging the fulcrum can be used. The areas of the plungers are dissimilar; thus, as shown, that of D is smaller than that of D', in order to obtain unequal pressures, and to effect the purpose of my improvement, as will hereinafter appear.

My improvement being thus constructed and arranged, the operation ofthe parts is as follows: Supposing the position of the valve to be as in Fig. l, the steam is admitted through inlet-port b and port b2 under the core cl of the valve; thence into main steam-port b5 to drive the piston to complete a stroke, the exhaust taking place through the opposite main port b4 under the center core c2 of valve, from thence out of exhaust. At same time, be it noted, the direct pressure of steam from boiler has entered the inlet-.port b1, and, by means lof the Vport d, raised the small plunger D, and in doing so passes through the port d1 into the steam-chest top of the valve. The excess of steam-pressure top of valve, owing to its increased area, passes through the port cl2 and raises the large plunger D', and in so doing, by means of the lever-connection with plunger D, causes it to close further admission of steam to the chest. The fulcruin having been supposed at center, it is plain that thus the steam-pressure top of the valve becomes less to that degree that the steam-pressure under the valve is the greaten -z'. e., the less pressure of steam top of valve With its increased area, being, therefore, counterbalanced by the greater steam-pressure under the valve acting upon less area, causes said valve to be automatically balanced, and relieved of its friction.

In case` the steam-pressure in the steamchest becomes reduced from condensation or other causes, then-the small plunger, on -account of thegreater pressure below the valve, will be forced up, and thus supply the -chest through port d1 With its loss ot' pressure. It the pressure under the valve C becomes reduced and a greater pressure is in the steamchest, then the larger plunger will be forced up, to permit such excess of pressure to escape through the exhaust-port d3. (See Fig. l.) This done, said plunger will also close. A greater pressure in the steam-chest can be achieved for the purpose ot a pressure-valve, by sliding` or changing the fulcrum inthe direction of the large'plunger. (See Figs. 1 and 3.) The excess of leverage will then be in fz vor of small plunger, and this raised admits the required greater pressure in steam-chest. f

My improvement, therefore, enables the valve to be balanced or to act as a pressure-valve, or be overbalanced, (by changing the fulcrum in the direction. of the small p1unger,)

and all this While the engine is in motion, .the engineer having the valve under perfect control.

By changing the positionl of the fulcrum all Wear that takes place can be compensated, or follow up whatever increase ot' area arisesfroin use; also, the s't'eam-chestfcan be reedfrom all dirt, grit, and impurities out of the exhaust d3, and otherwise my improvement possesses advantages readily apparent.

. What I claim isl. A lever having a changeable fulcrum, and carrying plungers arranged in a steam-chest with relation to a slide-valve, in vthe manner herein shown and described, and by means whereof the lesser pressure top of valve is counterbalanced by the greater pressure below said valve, forming an improved balanced valve, as set forth.

2. The combination of the plungers D D, le-

ver E, movable fnlcrum E', ports d2 cll d, with relation to a steam-chest and cylinder A, to operate as and forthe purpose set forth. In testimony' of said invention I have hereunto set my hand.' v

BENJAMIN BRAZELLE. Witnesses: v

WILLIAM W. HERTHEL, CHAs. F. MEIsNnR.

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