US94891A - Improvement in combined high and low-pressure engines - Google Patents

Description

THOMAS L. JONES, OF NATCHEZ, MISSISSIPPI.

Letters Patent No. 94,891,datedrSeptember I4, 1869. I IM' i IMPROVENIENT IN' CCMBINED HIGH AAND LOW-PRESSURE ENGINES.

The Schedule referred to in th'ese Letters Patent and making part 0f the Same- To all whom it may' concern:

Be it known that I, THOMAS L. J oNns, of Natchez, in the county of Adams, and State of Mississippi, `have invented a'new and-.improved Combined High and Low-Pressure "Engiriej and I do hereby declare that the following is a fhll, clear, and exactdescription of the construction and operation of the same, reference beiughad: to the accompanying drawings, `making a part of this specification, in whichp Figures l and 2 are side-views, showing the valves in dii'erent positions, a portionl ,of the walls of the valve-chests being broken away, to reveal the operation of the parts enclosed therein.

i Figure 3 isia detached View of valve n n.

This invention is an adaptation of my combined high and vlow-pressure steam-engine, patented April 14, 1868, No. 76,776, ,and` consists. in a new arrangement ofparts, whereby]1A am enabled to use my atmospheric valv'e (a portion of `my patent) in connection with that i'orm of` engines now in use on our western rivers, enabling them, with s'light addition of machinery and cost, to retain their present high-pressure steamboat-eugines,` and, with my improvement, giving them the advantage of a vacuum, increasing the speed of theirl forty-foot paddle-wheels three or four revolutions per minute, without additional press- Vure of steam.

This improvement I have practically tested, on a large scale, at Louisville, .Kentucky, on onel of our river steamboats, and it has proved to work to perfectionI in all its particulars. l

In thedrawings-- A is the cylinder-head; i

' B, the piston-rod;

`(l, the cross-head;

E F, two reciprocating rods, which wol-.k the valves,

themselves operated, `by a cam and yoke, from the main shaft;

a side pipe, arranged alongside of the cylinder, oil-.the opposite side to that Voccupied by the steam-chest, the latter not being shownin the draw- .iussi v I and J, two rock-shafts, the former worked by thev rod E, and thelatter by the rod I" t t', a A,rocking or lifting-lever, atiixed to shaft I. L L', two levers, operated, alternately, bythe toes H H, pipes', leading. from the ends of the main cylf inder into the side pipe G, at each end of 'the latter,

and shown here indotted lines; v K K', rods, connecting the levers L L to valves that open and close pipesV H H,respectively, and thusalternately opening a .passage'for the steam in its centre, through which steam exhz'iusts from thev valve-chest to the open air;

N', a side pipe, attached to the side of va'ilve-chest N; and

R, a pipe, leading from the centre of side pipe N to the condenser.

VThe operation of these severalparts `is briefly as v follows:

Then the vsteam exhausts from theleft-hand end of the main cylinder, it passes, through pipe H, into side vpipe G, the toe i being lifted, so as to open pipe H, and the toe t" being depressed, s'o as to close pipe H at that moment, as shown in tig. 1

When the steam exhausts from the right-hand endof the main cylinder, it also passes into side pipe G,

but through pipe H', lever L being up,and lever L down, as shown in tig. 2.

From side pipe G, in either case, the steam, under considerable pressure, passes directly into valve-chest M, where it forces up an atmospheric valve, m ml, and blowsofi, through pipe Q, down to an equilibrium with the atmosphere, or fifteen vpounds to the square inch. f

Ihe valve m m then falls vby its own weight, (assisted, if necessary, by the action ofa spring, m2,)

and, at lthat instant, two balanced.. valves, connected on one sten1,iz 1i1,in chest N, open and establish a direct communication from sidepipe G to the condenser, through the parts O M l N N It', and instantly, by the action of Vthe condenser, the remaining fifteen pounds of' steam are condensed, and a vacuuxn produced in the exhaust-end ofthe main cylinder. l

The li-ve steam is being admitted to the opposite end of the main cylinder meanwhile, so that the piston that operates rod B has a vacuum f 'o'n one side, and a full head of steam on the other side, at the same instant, and thus acts with the combined force `ot' a high-pressure and a-low-pressure engine.

The valves an m1 and a n1 are operated by means of a lifting-foot on vshaft J, similarto that show-n at i fi.

The two' valve-Steins m1 al are connected to a cross# gine awhile,

'steam to exhaust to the open air, whatever maybe the position of the cross-head and the other valves.

This arrangement not only insures the raising and lowering of va-lve mm1 at the proper instant, but pre- `vents all danger should anything connected with steam-chest N, its valves, or the condenser, get out of order, or refuse to act, since, in such case, the steam would simply blow off wit-hout going to the condenser, just as in a simple high-pressure engine. Indeed, it can be made to act as a-high-pressure cngine alone, by raising the cross-head, and fastening it up, in which position the `two balanced condenservalves 'n nl will be securely seated, and the valve m fm.l open.

In my large engines, I prom'de a sleeve aud lever v over rock-shaft J, for the special purpose of thus raising the cross-head, .and fastening it.

Among other advantages of this arrangement, it enables the engineer to ascertain, at any time, just what gain results 4from the employment of the condenser-exhaust in addition. to the open-air exhaust. He has only to shut ofi` the former, and run the ennoting the number of revolutions per and run the, engine an equal when acomparison of the show which minute, and then open it, time, noting the revolutions, revolutions made under each condition will is most advantageous.

In the large river-boats on which this improvement.

has been most fully and satisfactorily tested and demonstrated, a gain of three to four revolutions per minute over the high-.pressure engine has been. noted whenever the combination was employed.

In order to assist in securely shutting the valves n al, a spring, u2, may be provided under the valvechest.

The valve-rod nl will require but little packing, since the chest N is so connected with the condenser that the outward pressure is nearly always neutralized. Indeed, the pressure is generally inward on this'chest, so that the steam has no tendency whatever to escape from it, except to the condenser.

The throw of the valves m m1 n a1 maybe adjusted by changing their position on their stems, or by adjusting the cross-head or. the. liftiug-foot, or moving the cam employed at the main shaft to work the rod F. It is, therefore,- perfectly ,easy to regulate the working of any part of the apparatus, and it will be especially observed that the engine with my improvement works as well backward as forward.v

In fig. 1, the piston is at the right-hand end of the main cylinder, and the exhaust H is opening. Just at this instant, the cross-head raises valve m m1, making a free passage from the exhaust-end of the cylinder to the open air, and allowing all but fifteen pounds of steam to blow ott'. At the same instant, the valve a al has seated, cutting off the communication with the condenser. As it takes but an instant to blow oli` all the steam above fifteen pounds, the cross-head now comes down quickly, allowing valve m 1nl to close, and opening valve a al, so that the remaining fifteen pounds may go to the condenser. The passage tothe condenser continues open during the remainder of the stroke, andis only closed when, on the return-stroke, the toe i opens the exhaust H', atthe opposite end of the cylinder. At that instant, it closes momentarily, to allow the newly-exhausted steam to blow off to fifteen pounds, when it again unseats, as shown in `tig. 2, and keeps the way to the condenser open to the end of the return-stroke, and so on, as long as the engine is in operation. i

The valves n nl are balanced, consisting of a frame, e, two annular rings, a a, attached to the frame, and working steam-tight in the chest, two lcircular plates, n n, opening and closing the central orifice of the an nular plates, tached to that part of rod al which is fastened to the cross-head, and the plates a n being attached to that part of said rod which extends down through the bot tom of the valve-chest, and is connected to the spring.- It will be seen that the rod nl is thus in two parts, connected only by the slidingy parts e a n, as described. The construction of this valve is clearly exhibited in fic. 3.

Itowill be observed that the open-air exhaust Q communicates with the side of the valve-chest M, so that the valve m can rise above it-an arrangement which allows the steam to blow off before the valve reaches the end of its upward throw.

The upper end of the valve-chest, above the orificev Q, thus forms an air-chamber, which cushions the valve, and prevents all jar and shock. y

In practice, the valve is found to work as smoothly and silently under full head of steam as if operated by hand.

If necessary', the valve might be made to rise into the mouth of a downward-projecting tube, closed steam and air-tight at its upper end, in which case a perfect air-cushion would be provided for the Valve.

I do not wish to confine myself to the particular form of valve shown in fig. 3, but may use any other construction Iwhich,'adopted in place of that, would answer the purpose as well.

,When I employ the form of valve described, Ias shown, the simplicity and beauty of the operation of the parts are particularly noticeable, the simplevertical movement of the crosshead performing three functions, viz, operating the valve m m1, raising and lowering the frame e and annular plates ara, and moving, at the proper moment, the valve-plates n. It would be diiricult to effect such complex movements with simpler mechanism.

Having thus described my invention,

What I claim as new, and desire to secure by Letters Patent, is-- e 1. The combination of pipe 0,valvecl1est M, valve a, and pipe Q, of the valve-chest, with an air-chamber above it, substantially as set forth. V

2. The cross-head T, in combination with the valvestem a, fixed to it by a set-screw, the valve-stem mi sliding loosely through it, and the stop "u, to regulate the distance which the rod m1 slides through the crossfhead, substantially as and for the purposes set forth.

3." lhe combination and arrangement of the valvechests M N, valves on m1 n al, passage P, pipes Q R, cross-head T, and springs fm? al, substantially as described.

the frame and annular plates being atwhen the latter is arranged at the side-

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