US893188A - Cut-off valve for engines. - Google Patents

Description

No. 893,188. 'IIPATENTEDJULY 14, 1908.

- 1. 'B. McBLRoY GUT-OFF .VALVE FOR ENGINES.

I APPLICATION FILED APR.24, 1906- 2 SHEETS-SHEET 1.

I J awuzutoz No. 893,188. a PATENTED JULY 14, 1908 I. B. McELROY.

CUT-OFF VALVE FOR ENGINES.

APPLICATION FILED APR.24, 1906.

z SHEETS-SHEET 2.

UNITED sTATns PATENT OFFICE.

ISAAC ERWIN MCELROY, OF MUSOATINE, IOWA.

CUT-OFF VALVE FDR' ENGINES.

Specification of Letters Patent.

Patented July 14, 1908.

Application filed April 24, 1906. Serial No. 313,455.

The chief objects of this invention are:

first, to simplify and improve the construc tion and increase the efliciency of operation of rotary steam-valves and governing mech anism; second, to obtain by practicable means automatic control of the induction of steam or other propelling fluid, varyin the cut-off according to the load, without owever varying the counter-pressure-a result hitherto attained, it is thought, only in a Corliss engine also to secure sensitiveness in operation of the governor and cut-ofl, without impairing the accuracy or positiveness of action; third, to provide large full ports, sudden in opening and closing, thereby avoiding wire-drawing and condensation of steam by strangulation; and, further, to maintain a full open exhaust during the whole of the reverse stroke of the piston, excepting as may be necessary for cushioning.

One appropriate embodiment of the invention, applied to an ordinary reciprocatory steam-en me, is illustrated in the accompanying rawin s, which form a part of this specification. t is understood however that the invention is independent of the specific construction or style of engine with which it is incorporated, being adapted for general application, as well as susceptible of embodi ment in different forms, and of modifications in details of structure and arrangement of parts. Without restriction therefore to the particular construction illustrated, the invention will hereinafter be first fully described with reference to said drawings, and then more particularly pointed out in the appended claims. a p

In said drawings, Figure '1 is an enlarged horizontal section through the cylinder or piston-chamber and the valve-case, showing the piston and valve in elevation, also showing a cut-off governor in section. Fig. 2 is a horizontal section through the valve, valvecase, and contiguous portion of the cylinder. Fig. 3 is a vertical cross-section on line III III of Figs. 1 and 2. Fig. 4 is a cross-section on line IVIV of Figs. 1 and 2. Fig. 5 is a perspective view of the rotary valve. Fig. 6 1s a face view of the cut-01f governor.

The cylinder A, working-piston B, and

piston-rod C are shown as usual in recipro-1 cating en ines.

The va ve-case 1 is shown in a preferred relation, that is arranged longitudinally of and beside the cylinder A. Motive fluid,

steam, compressed air or the like, is supplied through the feed-pipe 2 shown in Fig. 4, which enters an intermediate part of the valve-case. Exhaust fluid is taken from opposite ends of the valve-case through the discharge pipes 3. from the cylindrical va ve-seat to opposite ends of the piston-chamber.

The illustrated valve, being designed to distribute and control the steam or other motive fluid for both sides of the piston-chambenis therefore a double or two-part valve. It is shown comprising two valve-heads, 6 and 7, alined and connected together, either integrally constructed as shown, or both splined upon the same valve-rod, or otherwise rigidly united. Said valve-heads rotate in cooperative relation to the steam- ports 4 and 5 respectively. They. are in the form of hollow cylinders, so constructed and internally divided by longitudinal partitions 8 as to.

provide in each valve-head an inlet-chamber 9 and exhaust-chamber 10. It is understood of course that the inlet and exhaust chambers at one side are inversely arranged with respect to those at the other side, since steam is admitted to one end of the cylinder or piston-chamber while exhausting from the other end. The annular space 11 between the valve-heads constitutes a medial supply chamber, which is in constant communication with the feed-pipe 2. Said chamber 11 is also in open communication with the respective inlet-chambers 9, through ports or openings 12 in the inner ends or end walls of the valve-heads. The exhaust-chambers 10 are of course closed to said medial supplychamber 11, but are in open communication through ports or openings 13 with exhaustchambers 14 in the outer ends of the valvecase, the latter being in communication with discharge pipes 3. Thus the double valve, as a whole, is in the general form of a hollow partitioned cylinder having five chambers, viz: the medial supply 11 and the opposite inlet-chambers 9 and exhaust-chambers 10.

Steamorts 4 and 5 extend;

' able relation thereto. preferably freely or loosely mounted on said.

The outer wall or shell of each valve-head is provided with an inlet-port 15 and exhaustport 16, open from the inlet-chamber 9 and exhaust-chamber 10 respectively, and adapt ed to register in alternation with the particular steam- port 4 or 5 in the valve-seat with which the particular valve-head is associated. These inlet and exhaust ports 14 and 15 are cut or formed longitudinally in the shell of the valve, and are made large or wide to maintain continuous registration with the steam- ports 4 and 5 during admission and exhaust phases of rotation of each valve-head. The valve-shaft being geared to rotate once per each rotation of the crankshaft, the registering steam-ports are sudden in opening and closing, thereby avoiding wire-drawing and condensation of steam by strangulation. The exhaust-ports 16 are especially made wide enough to maintain a continuous full open exhaust during the reverse stroke of the piston, except as may be desired at the completion of the stroke for cushioning. In the constructionillustrated, the outer shells of the valve-heads, in which the ports are formed, consist of turned sleeves fitted tightly on the circular end walls of the respective valve-heads and revolubly fitted within the valve-chamber.

The inlet or live-steam side of each valvehead is provided with an automatic variable cut-off device, revolving with the valve, and connected with a governor operated by the speed of the engine to control the induction of steam in such manner as to secure uniformity of speed. In the form shown, the said riding or revolving cut-off is an internal segmental plate 17, movably or slidablyfitted under the shell of the valve-head at the cutoff or rearward side of the inlet-port 15 thereof, and carrying at its front or advancing ed e a flange or lip 18, the latter being movabIy arranged in the said inlet-port or between the ends of said port and having an outer convex surface co-cylindrical with the surface of the valve-head. Hence the passing of the flange or lip 18 over the steam- port 4 or 5 in the valve-seat determines the period of cut-off, or terminates the induction of propelling fluid, allowing the propelling fluid thereafter to act expansively. Said cut-off device 17 is carried by a radially arran ed spider or support 19, co-axial and revolu le with the valve-head, but capable of a vari- The cut-off device is spider or support 19, as by pin and slot fastenings 20, or by other suitable means, whereby the riding cut-off is always properly seated by pressure of steam on the inner or end face of the segmental plate 17.

As'shown, the spiders or supports 19 for the two cut-offs are keyed or fixed on a shaft 21, which is revolubly arranged in the center of thevalve,within ahollowvalve-shaft 22, the

latter being keyed or fixed to the valve. The said cut-off shaft 21 passes out through said valve-shaft 22 beyond one end of the valvecase. The valve-shaft 22 may be either an independent hollow shaft, as shown, or it may be an extension of the valve-rod proper 23, which is shown extending out through the opposite end of the valve-case. The cutoff may be controlled by any suitable device, as by means of a speed-governor or other mechanism operating on the cut-off shaft 21 For example, in the case of a locomotive engine, a lever may be employed to control the variable cut-off. However, as a part of my invention, I have devised the construction now to be described, in which is employed a speed-governor revoluble with the valve and operatively connected with the cut-oil shaft.

On the end of said hollow valve-shaft 22- is a,

centrifugal governor 24, of any suitable type or construction, which is connected with the cut-off shaft 21 in such manner as to rotate the same, with the valve-sh aft, but at a variable relation thereto, according to the speed of the engine. Hence any variation in speed causes a variable relative position of the shafts 21 and 22, thereby moving the riding cut-oif device, so as to lengthen or shorten the period of admission. The illustrated governor comprises a disk or element mounled on the valveshaft 22, and carrying springconnected weighted levers 25, which are connected by links 26 with a yoke or cross-piece 27 to the cut-off shaft 21, thereby making a yielding connection between the shafts adapted to turn them together but allowing a variation in their relative positions under the centrifugal action of the weights. The governor being thus directly and closely connected with the cut-off, has its sensitiveness greatly increased without impairing its positive action. It will be noted, moreover, that the variations in the periods of admission, due to the action of the governor and riding cut-off, does not affect the counterpressure, since the cut-oif is varied by a restriction of the width of the inlet-ports 15, without however varying the position of the valve itself, nor varying the position or the size of the exhaust-ports 16, which latter maintain a full open exhaust for the reverse stroke of each side of the piston.

The valve may of course operate two or more cylinders as well as one cylinder, in which instance the valve-case would be arranged between the cylinders, steam-ports being provided for the respective cylinders, each for. successive registration with the inlet and exhaust ports of the valve.

Having thus fully described my invention, what I claim as new and desire to secure-by Letters Patent of the United States is 1. In rotary valve mechanism, the combination of a cylindrical valve-case having a ing a hollow cylindrical head having lateral admission and exhaust ports adapted to register with the port in said valve-case, and a variable riding cut-off carried inside said nal riding cut-off mounted on said shaft comprising a loosely held segmental plate fitted under the cut-off side of the admission port and having a flange or lip fitted within said admission port against'the interior of the valve-case, said cut-off being seated by steam pressure.

3. In rotary valve mechanism, the combination of a cylindrical valve-chamber having a port therein, a hollow rotary valve fitted in said chamber and having a cooperative inletport, a variable cut-off device revoluble with the valve and movably arranged in the inletport thereof, said cut-off device having an outer surface flush with the interior walls of the valve chamber and being freely or loosely held, and seated by pressure of motive-fluid in the valve.

4. A rotary valve comprising a hollow cylindrical shell having a lateral inlet-port, an independently-turnable rod or shaft axially arranged therein, a radially-arranged spider or support on said rod, and a riding cut-off device carried by said spider, said device comprising a segmental plate fitted under the inner wall of the valve-shell at the cut-off side of its port and being loosely fastened on said spider.

In testimony whereof I affiX my signature, in presence of two witnesses.

ISAAC ERWIN MQELROY.

Witnesses:

G. ALLBEE, C. W. BENSHOOF.

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