US439449A - wallis - Google Patents

Description

(No Model.)

2 Sheets-Sheet 1.

A. H. WALLIS. ENGINE STARTER.

No. 439,449. Patented Oct. 28, 1890.

(No Model.) '2 Sheets-Sheet 2.

A. H. WALLIS.

ENGINE STARTER.

No. 439,449. Patented Oct. 28, 1890.

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UNITED STATES PATENT OFFICE.

ARTHUR H. VALLIS, OF BASINGSTOKE, ENGLAND.

ENGINE-STARTER.

SPECIFICATION forming part of Letters Patent No. 439,449, dated October 28, 1890.

d April 30, 1890. Serial No. 350,045. (No model.) Patented in England December l9. 1889,11'0. 20,4A3, and in South African Republic March 28, 1890, No. 166.

To all whom it may concern:

Be it known that I, ARTHUR HERBERT WAL- LIS, engineer, of North Hants Iron Works, Basingstoke, in the county of Hampshire, England, have invented a new and useful Improvement in Starting and Stopping Apparatus .for Compound-Engines, (for which I have obtained patent in South African Republic, dated March 28, 1890, No. 166, and in Great Britain by an application for patent, which patent, when granted, will bear date December 19, 1889, No. 20,443,)of which the following is aspecification.

As compound engines are usually arranged, steam, after performing work in one cylinder, exhausts therefrom into a reservoir, whence it supplies another cylinder at lower pressure, and this may be repeated three or more times. It is difficult to effect the stopping and starting of an engine of this kind, because, in the case of stoppage, although the supply to the high-pressure cylinder may be cut off, the reservoir or reservoirs go on supplying the low-pressure cylinder or cylinders, keeping the engine in motion, and in the case of starting, although the high-pressure cylinder may be supplied, there is no supply to the low-pressure cylinder or cylinders.

My invention relates to means of overcoming these difficulties, which I effect in the following manner: I provide shut-off valves for the slide-jackets of the several cylinders so arranged that they are simultaneously opened or closed by one action, and I furnish the reservoir, or each reservoir, if there are several of them, with a supply-pipe governed by a reducing-valve so adjusted that the reservoir is supplied with. live steam only when the pressure in the reservoir is below a certain minimum suflicient for acting in the lowpressure cylinder connected to the reservoir. Thus by the one action of closing the valves I can shut oif steam from all the cylinders, so causing immediate stoppage of the engine, and as the reservoirs are always, during working, charged up to the minimum pressure required by the one action of opening the valves, I admit steam to all the cylinders, causing the engine to start.

Figure 1 of the accompanying drawings is a part side view, and Fig. 2 is an end view, of the cylinders of a compound two-cylinder engine to which my invention is applied. Fig. 3 is a transverse section of the cylinders through the high-pressure slide-valve, and Fig. 4 is a similar section through the lowpressure slidevalve. Figs. 5 and 6 are vertical sections on planes at right angles to one another; and Fig. 7 is a sectional plan showing, on an enlarged scale, a convenient form of reducing-valve which I employ.

I provide sluice-valves A and B or other suitable stop-valves by which I can simultaneously out off the steam-supply to the high and the low pressure cylinders, respectively, the stems of these valves being both connected to arms of one rocking-shaft C, so that on moving this rocking-shaft by a lever D, both valves A and B are simultaneously closed or opened for the purpose of stopping or starting the engine.

I provide a reducing-valve E, Fig. 3, which may be of the construction shown in Figs. 5, o, and 7. It has two valves on the stem of a piston Q, which is pressed down by a loaded lever, so that when these valves are unseated there is communication between two branches F and G. The branch F communicates with the space H of the high pressure slidejacket, which space, when the valve A is open, is supplied with steam direct from the boiler by the pipe P. The branch G communicates with the reservoir space R, which receives the exhaust from the high-pressure cylinder, and which when the valve B is open supplies the space L of the low-pressure slide-jacket. The apparatus operates as follows: By moving in one direction the lever D both the valves A and B are closed, cutting oif steam from the slide-jackets of both cylinders, and the engine is stopped. hen it is desired to start again, both the valves A and B are simultaneously opened by moving the lever D in the opposite direction, and if the reservoir R should at that time contain steam at pressure sufficient for the low-pressure cylinder the engine is started; but should the pressure in B have become too low or tended to become too low then the reducing-valves E operate, admitting steam from the slide-jacket H to the reservoir R, thus maintaining in R the pressure determined by the adjustment of the reducing-valve E. This pressure is adjusted by proportioning the load on the lever to the area of the piston Q, so that the valves attached to that piston open only when the pressure upward on the piston Q, which is the pressure in R, is less than the load on the piston downward. Obviously, instead of a weight the piston Q might be loaded by a spring or by the pressure on another piston connected to it.

I prefer to provide in additon to the reducing-valve E a check-valve M, closing a passage from F to G, so that when, although steam is shut oif, the momentum of the flywheel continues the movement of the engine, causing a pumping action in the cylinders, steam can pass from the reservoir R to the high-pressure slide-jacket, thus maintaining the high-pressure slide-valve in equilibrium, and so preventing it from being forced away from the facing.

Ordinary engines usually have a single shut-off valve, which is for the high-pressure supply, and as there is steam coming from the high-pressure cylinder and supplying the lowpressure cylinder, it is impossible to stop the engine as rapidly as is desirable, for though the high-pressure supply is cut-off there is sufficient steam in the reservoir to keep the lowpressure cylinder moving. In consequence of the lack of means to shut off the steam-supply from both cylinders simultaneously serious accidents have occurred when such engines are applied for the winding in mines, because if the engine cannot be promptly stopped when the cages reach the top there is a break-down. By providing each cylinder with a shut-01f valve and connecting such valves to one lever the stoppage of the engine can be rapidly effected by closing the valves, and there being always supply of steam to the low-pressure cylinder admitted to its reservoir by the reducing-valve, the engine can be quickly started by opening the two valves.

Although I have shown my invention ap plied to a compound engine having only two cylinders, obviously when there is a greater number of cylinders the apparatus may be repeated for each successive pair. For example, when there are three cylinders, with a reservoir between the first and second and a reservoir between the second and third, I provide three shut-0E valves, one for each cylinder, connected to one lever, and two reducingvalves, one between the slide-jacket of the first cylinder and the reservoir, which its exhaust supplies, and one between the slidejacket of the second cylinder and the reservoir supplied by its exhaust. The reducingvalve in each case operates automatically, supplying the reservoir with steam when steam is required.

Reducing-valves have heretofore been proposed for supplying the reservoir of the lowpressure cylinders of compound engines; but myinvention resides in the combination, with a reducing-valve, ot shut-off valves simutaneously operated for both cylinders.

Having thus described the nature of my invention and the best means I know of carrying the same into practical effect, I claim- In combination with the cylinders and intermediate reservoirs of a compound engine, shut-01f valves, one for each cylinder, connected to one lever or motor, by which they are simultaneously opened or closed, and an adjustable reducing-valve in communication from the supply of each cylinder to the reservoir supplied by its exhaust, substantially as and for the purpose herein set forth.

In testimony whereof I have signed my name to this speeification, in the presence of two subscribing witnesses, this 16th day of April, A. D. 1890.

, ARTHUR H. WALLIS.

Witnesses:

OLIVER IMRAY, Patent Agent, 28 Southampton Buildings,

London, W. O.

J NO. P. M. MILLARD, Clerk to Messrs. Abel d2 Immy, Consulting Engineers and Patent Agents, 28 Southampton Buildings, London, W. C.

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