US364207A - barnaby - Google Patents

Description

C. W. BARNABY.

STEAM ENGINE VALVE.

` Patented June 7, 1887. .0.9,

(No Model.)

UNITED STATES PATENT OFFICE.

CHARLES W. BARNABY, OF SALEM, OHIO, ASSIGNOR OF ONE-HALF TO THE BUCKEYE ENGINE COMPANY, OF SAME PLACE.

STEAMENG|NE VALVE.

SPECIFICATION forming part of Letters Patent No. 364,207, dated June 7, 1887.

Application filed October 2, 1886. Serial No. 215.120.

To all whom it may concern.-

, Beit known that I, CnAnLEs W. BAENABY, Y

of Salem, in thc county of Columbiana'and State of Ohio, have invented a certain new and useful Improvement in Steam-Engine Valves,

of which improvement the following is a speciiication.

My invention relates to eutofl` or expansion valves for steanrengines of the cla-ss which 1o operate within box or chambered main or distribution valves through which steam passes to the cylinder, and its object is to reduce, as far as practicable, the dimensions of the steamehambers within the main valve, thereby attaining greater strength and rigidity in resisting the internal pressure of the steam upon the main valve, which tends to press its walls outwardly and disturb the contour of its working-faces.

@o To this end my invention, generally stated,

consists in the combination of a box or chambered main valve having a steamchamber provided with a supply-opening and deliveryport at each of its ends, and a cut-off valve 2 5 composed of a pair of recessed or chambered sections connected one to the other and fitted to reciprocate over faces inclosing the outer ends ofthe main-valve steam-ports.

The improvement claimed is hereinafter 3c fully set forth.

In the accompanying drawings, Figure l is a vertical longitudinal central section through a steam cylinder, valve chest, and valves, illustrating the application of my invention; Fig. 2, a plan or top View of the cut-off valve detached; Fig. 3, a transverse section through the same at the line x x of Fig. .2, Figs. 4 and 5, longitudinal sections through one of the steam-chambers of the main valve, showing .fio the cutoff-valve section in positions which completely open and completely close, re-

spectively, the steam-port; and Fig. 6 a simi-` lar section illustrating a, modification of the form of the eut-off valve.

My invention is herein illustrated as applied in a steam-engine, the cylinder l of which is closed at its ends by heads 2, in the usual manner,` and is fitted with a piston, 3, secured upon a pistoirrod, 4. Steam is admitted to 5o and exhausted from the opposite sides of the (No model.)

pist-on 3 through ports 10, adjacent to the ends of the cylinder, by a main valve reciprocated by suitable valve-gear in a valve-chest, 5, fixed upon the cylinder above the ports 10, and closed by a hollow cover or back, 6, to which steam from the boiler is admitted by a pipe communicating with an opening, 9, in the outer shell. rlhe main valve is of the box or chambered type, and is composed of a pair of end steamchambers, 1l, connected by a lon- 6o gitudinal passage or tubular body, l1, and working between equilibrium-rings 7 in the inner shell of the valve-chest cover and faces on the cylinder surrounding the ports l0.

Each of the steam-chambers 11 is provided 65 with a supply-opening, S, in its top, which communicates with spaces in the adjacent equilibrium-ring 7, (or both chambers maybe supplied from a common opening inthe body l1,) and with a lower delivery-port; 9, through 7o which steam passes into the adjacent cylinderport 10 when the port 9 is brought over the same in the traverse of the valve and un covered by the cut-off valve, presently to be de scribed. Theinterior of theinainvalvc is con 75 tinuously in communication with the steamsupply, and in the reciprocation of the main valve steam is alternately admitted to one of the cylinder-ports l0 and exhausted through the other into the valvechest, which is pro- 8o vided with an outlet communicating with a condenser or exhaustpipe.

The construction shown is of the description usuallyknown as the Buckeye valve, as exemplified in the patent of J. V. Thompson, 235 No. 162,714, April 27, 1875, and others; but my invention is equally adaptable to other forms in which the working-space is necessarily or preferably limited, either by reason of insufficiency of permissible dimensions or oo deficiency of the strength which is attainable Ain valves of the ordinary form operating in a live-steam chest.

It is the usual practice to so construct and set valves of the class illustrated that they shall 9 5 properly control the opening and closure of the exhaustingcylinder port and the opening of the cylinder-port receiving steam, the closure of the latter being eifected and controlled by a cut-off valve working within the main rco valve over the steam-ports thereof. As heretofore constructed, so far as myknowledge and information extend, the eut-o valve has consisted of a pair of iiat plates connected to each other and to a valve-stem, and, under the control of the governor, traversing over the steamports of the main valve, the cut-off valve admitting steam through said ports to the cylinder and cutting off steam earlier or later in the stroke-in conformity with varying conditions of load or pressure, or both, as regulated by the governor.

In order to attain a rapid movement of the cut-off valve, and so insure a reasonably sharp cut ofi", the movement of said valve has been made materially in excess of that which would be required to merely open and close the mainvalve steam-ports, the ordinary practice being to make the traverse of the eut-off valve equal to that of the main valve, or four times the width of the main-valvesteam-ports. The eutoff valve is also so set in the main valve that when at mid-travel it covers about one-half the width of the ports at each end of the main valve, and thus the cutting off of the steam is effected while the cut-off valve is moving most rapidly. It will be seen, further, that the cutoff valve acts only through one-fourth of its travel, the remaining three-fourths of its movement being past the point of full closure on one Side and past the point of full opening on the other.

To prevent the cut-off valve from passing entirely beyond the ports, reopening-at one side after closing at the other, it has been neces-l sary to make the width of each of its sections` equal to at least three times the width of the port which it covers,and such increase of width, in addition to the required travel and clearance, necessitates objectionably large end steamchambers in the main valve, their width being usually about eight times that of the port. Expensive and complicated valve-gears have been devised and operated, having for their purpose a rapid closure of the steam-portwith a reduced travel of the cnt-off valve7 so as to reduce correspondingly the width of the steanr chambers, the cutoff val ve being in such case caused to move much more rapidly at the middle and more slowly at the ends of its stroke than when operated by au ordinary eccentric or crank. Such gears, while attaining the object of their design, have not been found fully satisfactory in practice by reason of the expense and complication necessarily incident in their construction.

Under my invention I reduce both the travel and the width of the sections of the cutoff Valve, and thereby correspondingly reduce the width of the chambers of the main valve Without modification of or addition to the actuating-gear heretofore employed, by forming an internal recess or chamber, 13, in each of the sections 12 of the cutoff valve, said chambers being open at bottom to the mainvalve faces or seats which surround the ports 9, and against which the cut-off sections iit, and-having their end walls made as thin as is consistent with proper strength, in order to afford the largest practicable degree of opening of the ports 9 relatively to a given travel of the cut-off valve. Y

The chambers 13 may be either entirely open on their sides adjacent to the main-valve faces, as shown in Fig. 6, or, as is preferable in practice, be provided with abridge or bar, 14, having a port on each of its sides, as iu Figs. 1, 3, 4, and 5, the latter construction affording the advantage of increased bearing-surface for the cut-off-valve sections upon their seats or faces on the main valve without interfering with the passage of steam through the ehambers 13 to the ports 9. The cut-off valve is shown in Fig. 1 as moving to the right and just prior to its closure of the ports 9, steam being admitted on the inner sides of the sections 11 through their chambers 13 to the ports 9, and on their outer sides directly to the ports, and the passages through and past the outer sides of the chambers 13 being open simultaneously, the saine results practically are obtained with Onehalf the travel of the ordinary valves. The sections 11 are connected by a b olt or bolts, 15, so as to move coincidently asv reeiprocated by a common valvestem, 16, passing freely through the stein 17 of the main valve, and may, if desired, be located outside of the main-valve ports 9, so as to cut off steam while moving toward the center ofthe main valve,instead of while moving toward the ends, as in the instance shown.

In the employment of my improved cut-off valve I am enabled to effect a reduction of travel of one-half and of width one-sixth, and thereby reduce the width of the 1nain-valve steam-ehambers from eight times the width of the ports to five, and attain the further advantage of effecting a reduction in the diameter and throw of the cut off eccentric, thereby diminishing the weight, cost, and friction of the same and of its strap.

I claim as my invention and desire to secure by Letters Patent- The combination of a main valve having a closed steainchamber at each of its ends communicating with a supplyopening and provided with a delivery-port, and a cutoff valve composed of two connected sections, each iitting against a face or seat inclosing one of the ports of the main valve, and having auinternal recess or chamber which `is open on its side adjacent to said face, substantially as set forth.

CHARLES V. 'BARNAB Witnesses: y

ALBERT CAMERON, PETER AMBLER.

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