US21813A - Peters - Google Patents

Description

4o l l f 4a UNITED STATES PATENT OFFICE.

BENJN. BUNGE, OF NE\V YORK, N. Y.

CUT-OFF VALVE FOR STEAM-ENGINES.

Specification of Letters Patent No. 21,813, dated October 19, 1858.

To all 'whom it may concern.'

Be it known that I, BENJAMIN BUNCE, of New York, county of New York, and State of New York, have invented certain new and useful Improvements in the Cut-Cif Valves of Steam-Engines; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being made to the annexed drawing, making a `part of this specification, in which- Figure I is a longitudinal vertical section through the steam chest. Figs. II, III and IV are of parts in detail.

Similar letters refer to similar parts throughout.

My invention is adapted to work in connection with any of the ordinary forms of slide-valves.

The improvement lies chiefly in the mode of admitting the steam to the slide-valve, and consists in attaching to the slide itself a tube which communicates from its interior with the induction passage on the face of the slide, and which tube is slotted on its sides to receive steam from the steam-chest, in which it is situated. The slotted tube is surrounded by a sleeve or cylinder, which is also slotted, and partial rotation is given to the sleeve so that the slots in the two may either coincide, or may close each other, as required, by stops fixed within this chest and against which stops a pin projecting from the sleeve is brought to strike as the tube and its sleeve are carried along by the movement of the slide-valve to which those are affixed.

I am aware that a cut-off has been made with a slotted tube and cylindrical slotted seat over it, yet this hasnot been combined with the slide-valve so as to be moved along with it, without the requirement of an independent set of connections to give it its play.

y improvement will be readily understood by the following description of the construction.

The slide-valve is shown at A in Figs. I and II and has the usual openings upon its face for admitting and exhausting steam, as (l) 21'). At each side rises a hollow post A; the channels in which communicate with the induction passages (b). Into these posts a cross tube is fitted so as to lill up the holes shown in their tops, and is so secured as to make a steam tight joint around the external edges, the tube itself being closed at both ends. This tube is seen at C, Fig. I, and is also represented detached in Fig. III. The apertures are narrow slots extending lengthwise of the tube, as at C', and may be distributed equally around the tube, as shown. The aggregate area of the whole should be equal to that of the induction ports. This tube forms the cut-off valve seat; the cut oft1 valve is a cylinder or sleeve divided lengthwise into two segments and is represented at D. The bore of this is such as to fit upon the surface of C, and through this cylinder is also a series of slots D', of like capacity and shape with those on C. Each segment of the valve has a flange set oft as seen at (c), for the purpose of clamping the two parts upon the tube, a space being left between to form a slotopening in each side. Consequently, the two parts of the sleeve are not exactly semicylinders.

Fig. I exhibits a sectional view of the cut off valves in place within the steam-chest. In valve No. 2, the position shown is that wherein the steam apertures in C and D coincide, while the valve No. l is so turned as to exhibit the slots in C closed by the cylinder D.

The halves of D are clamped upon the tube C by screws passing through the set ofi flanges (e), or they may be kept together by a spring which sha-ll be constantly acting to draw them toward each other, serving to keep always a tight surface by closing up as fast as the wear requires. There is a pin projecting from the cylinder D by which its vibratory motion is obtained.

The operation is as follows: The valves A, playing back and forth as usual, open the steam and exhaust ports on the great cylinder, and the cut-off is of course carried along with it. As these movements take place the pin strikes two stops before the slide-valve reaches the end of its stroke. By this means the cylinder D is turned partially around on its tubular axis C which forms its scat. These stops are on opposite sides of (i) and are represented by (O) and (O). The valves are shown at half-stroke; No. 2 is over the exhaust port and No. l over the steam port. The pin strikes the stop (O) and the cut olf is thus turned so as to make both sets of apertures viz. D and C, coincide. The pin on valve No.

l is shown as being struck by the stop (O), so that D has been turned sufficiently to close the aperture C, the cut-off thereby being eected. The piston noW travels for the remainder of its stroke and the valves are reversed. As (7)) of valve No. 2 cornes over its steam port (8),.stea1n Will pass through all the slots D and C from the steam-chest, then through the tube C and down the hollow posts A and through the valve into the cylinder of the engine7 the valvefNo. l being at that time over its eX- haust port. The pin (i) of No. 2 Will now be brought so as to strike (O) and the cutoii' etfected by turning D7 While the pin on No. l strikes the stud (O) and opens its steam passages. The degree of expansion Will be regulated by the position of (O),

` for the cut-oit Will be sooner or later according to its position in the path of the slide valve. 7 hen therefore a variable cutoit' is desired (O) is inade, adjustable by any suitable mechanical contrivance and as shown in Fig. I. The stops (O) are always fixed.

I claim- Combining with a slide valve of ordina-ry character, a cut-off valve, constructed substantially as Adescribed-that is to saythe slotted tube secured in a liXed position upon the slide, said tube having its ends so closed that the steam shall pass to the valve through the slots, and having also upon it y In Witness whereof I have hereunto set my hand.

BENJAMIN BUNGE. Ttnesses J. P. PIRssoN,

S. H. MAYNARD.

Images