USRE7585E - Improvement in combined high and low pressure engines - Google Patents

Description

T. L. JONES.

COMBINED HIGH AND LOW PRESSURE ENGINES.

No; 7,585. Reissued April 3, 1877.

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I g I I I I I Y I I I I I I IWITNE'SSES. I INVENTDFI.

UNITED STATES PATENT O CE:-

THOMAS L. JONES, or NATeHnz, MISSISSIPPI.

IMPR OVEMENT IN COMBINED HIGH AND LOW PRESSURE ENGINES.

Specification forming part of Letters Patent No. 76,77}; dated April 14, 186B; reissue No. 7,58 dated April 3, 1877; application filed October 10,1874.

Toa'il whom it may concern Be .it known that I, THOMAS L. JONES, a

'resident of Natchez, Adams county, State of a hi h-pressure and of a low-pressure steamcon ensing engine; and it consists, mainly, in the peculiar disposition of the exhaust steam, substantially asis hereinafter set forth.

It further consists in the means employed I in efl'ecting such disposition of the exhaust steam,substantially as is hereinafter described.

The accompanying drawing represents a slide-valve engine.

A. represents the steam-chest B, the cylinder; 0, the valve-rod D,"the piston; E, the piston-rod; F, a pipe leading to a condenser; and G G, exhaust-pipes leading to the open air, and respectively provided with air-tight valves 9 g, which seat! downward.

In Fig. '1, m represents the upper and m I the lower steam-port, the former, m, branching into two ports, a and a and the latter, m, branching into two other ports, a and a,

.and all passing up through the valve-seat and into the steam-chest proper. Between the ports cand a and extending down from the face of the valve-seat, is what I term a coudenser-port, 0. Similarly arranged between the ports a and a. is another condenser-port, 0 Both the condenser-ports connect with the pipe F, as shown in Fig. 1. The steam is supplied fromthe boiler through a pipe, H, which may be connected with any suitable cut-ofi. The two ports a and at are arranged above the middle of the steam-chest, and the ports a and a below the middle of the chest. There is an exhaust-port, i, in the valve-seat, between the middle of the chest and the port V a and another exhaustort 4" similarl a'rranged between the middle of the chest and the port a These lastmentioned ports 1' and 1" respectively connect with the exhaust-pipes G G, Fig.1. a

The valve of the engine is a slide-valve. As shown in ,Fig. 2, it is, in its front orunder side, and toward its upper end,.provided with a chamber or recess, n, which, as hereinafter '1 the pipe H circulates.

. The operation of the invention is as follows:

'Let the piston and valve be in the position shown in Fig. 2, the piston moving upward',' or to the left, as seen in the drawing, and the valve moving to the right. In this position the live steam will feed through port a to the cylinder below the pistomand the steam in the cylinder above the piston will he exhaust ing through the port a, recess n, and condenser-port 0. Ports 0., t, a, and 6 will be I closed, and the communication with the ex-.

haust-port i will be closed, so that no steam can escape through-it.- When the piston;

reaches the end of its stroke, moving to the left, the valve will have moved, so tap to the right as to close the condenser-port p. The

steam-port a will still be closed, so that no 1 live steam can escape through port a, recess 'n, and exhaust 1', which will be in connection. V

At the same moment,'-in the lower end of the steam-chest, port a will be closed, and port a will be put in communication with exhaust 1; n I

through the recess a, and in an instant the live steam in the lower end of the cylinder will force the valve 9' up, and exhaust to the open air until the steam within the cylinder is reduced to a pressure, of fifteen pounds to the inch, or one atmosphere, when the valve.

will of itself close. The next instant, the

valve still moving to the right, the portopens, and live steam passes into the cylinder above the piston, which begins its down- There is a stearhmpacc, 'r,fj I I through which live..st.eam admitt ed.t f ll. Y

stroke. As the valve in its movement opens port a it closes port a, and severs all commu- V nication from the upper end of the cylinder to the condenser-port e or the exhaust i; but at the same time it opens a communication from the lower end of'the cylinder to acondenser (not shown) through port a, recess a,

vand condenser-port e, and the steam in the "stroke in the same manner as l have described its passing to the upper end of the previous --stroke-from the position in which it was first seen, as in Fig. 2. The piston having arrived at the lower end of its 'downstroke, the same movement of the parts takes place that I have described as taking place when the piston reached the upper end of its stroke, but in an inverse manner. It will he noticed that the exhaust end of the cylinder is in connection with the open-air exhaust during a small portion of the stroke only. During the remainder' 'of the stroke the open-air exhaust is shut off, andthe communication is open from the cylinder to the condenser. It is only necessary to have the open-air exhaust in connectionwith the cylinder tor a very brief time,

, asthe inner steam-ports and the open-air exhaust-ports are large and close together, and the passage through the exhaust-pipe may be made perfectly straight, afiording a free es (in e to the steam when in connection.

tispreferahle to arrange the arir-iusparts so that the condenser shall not be put ineonnection with the cylinder when the crank is passing" the dead-point, but a moment after,-

when it has passed twenty or thirty degrees beyond that point. The additional power then imparted to the piston by the formation of the I vacuum in the cylinder will be thrown upon the crank. at a favorable moment to utilize it to the utmost extent. At the same time care should be taken that the crank should :not pass-too far beyond the dead-point before the condensation takes place, since the sooner the increased power is applied the longer will such power have an opportunity to exert itself upon the piston. In thus disposing of the exhaust steam, as in the manner set forthviz., exhausting, the steam at each stroke of the piston to the open air only until the steampressure at the exhaust end of the cylinder equals the pressure of the atmosphere, and then diverting the remaining one atmosphere into a condenser-t he etficicncy of the engine is largely increased.

Having described my intention, what I M, and space 7, valves 9 g, pipes F and H, and valve 0 a 0, provided with the recesses u n, substantially as described and shown.

THUS. L. JONES. 4 Witnesses;

FRED PARSONS, H. Y. CHILD.

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