US122269A - Improvement in valve-gears for steam-engines - Google Patents

Description

Q52.; JOHN c. MACDQNALD.

Improvement in Valve Gear for Stam Engines.

.Patented Decac26, 1871.

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Uivrrnn l Srnfrns JOHN C. MACDONALD, OF ST. LOUIS, MISSOURI.

IMPROVEMENT' IN4 VALVE-SEARS FOR STEAM-ENGINES.

Specication forming part of Letters Patent No. 122,269, dated December 26, 1871.

To all whom 'it may concern.-

Be it known that I, JonN C. MACDONALD, of

St. Louis, in the county of St. Louis and State oi' Missouri, have inadcxcertain new and useful Improvements in Valve-Gear for Steam-Cylinders; and I do hereby declare that the following is a full and true description thereof, reference being had to the accompanying drawing and to the letters of reference marked thereon.

The object oi' the improvements here presented is to dispense with valve-rods and connecting attachments ordinarilynsed to operate piston-rods and pistons oi' steam-cylinders, and to gain the y required reciprocating motion for the piston byr the direct action oi steam pressure or power.

To achieve said object the nature of this invention relates: First, to the peculiar arrangement and construction of auxiliary cylinders and their reverse acting stops and slidevalves, in combination with the main cylinder oi'steam-engines.

\ Secondly, to the arrangement of inductive and Y exhaust steam-passages and ports, by which the steam-power shall operate the valves in the auxiliary cylinders at regular periods to impart the y required reciprocating motion to cylinder-pisy Fig. 5 lis a transverse section at line m4 m4.

A is the main cylinder. A1 is the piston-cyl- A2 the piston=rod as ordinary. The main cylinder A is provided with main steam-ports a, al a? a, the said ports a al communicating from i vcylinder steani-space with the steam-chest A3,

the said ports c2 a?, however, being arranged horizontally and leading to the exhaust-pipe. The

steam is fed into steam-chest A3 through side v port a", (see Fig. 5,) the exhaust escaping ont of main exhaust a5, Figs. l and2. WVithin the steamchest o n top cylinder A are the auxiliary cylinders, constructed, arranged, and provided with the valve-gear as follows: The slide-valve cylinder B is provided with proper piston B1. In order to form the required steam-tight joints for said piston the heads B2 of cylinder B are cored with projecting cylindrical faces Within and Without said cylinder. (See Figs. l and 2.) .The joint thus formed obviates steam-jacketing, also is more durable and reliable. At the ends of the piston-rod of piston Bl are valve-heads C C, these being adjustably attached to said rod ends by proper set-screws. Further, the valve-heads G O are properly mortised to receive the bii'urcated extensions of the reverse acting slide-valves D D. The body of said valves is formed D-shaped, being cored hollowr to carry the exhaust steam from either end of cylinder alternately to main exhaust. The arrangement, therefore, ofthe auX- iliary cylinder B and its reverse slide-valves D D is such that said valves shall open and close the main inductive and exhaust ports a al a? a3, as illustrated in Figs. l and 2. Also, forming part of the cylinder B is the further auxiliary cylinder E, cored with proper inner shoulders to limit the stroke of its stopyalve E,Which is constructed and arranged as follows: The said stopvaive E consists of cylindrical section FF' formed ywith thc respective valve or piston-heads ffl.

(See Figs. 3 and 4.) In order to unite said sectional Valve E Within the cylinder E, the sectional part F has at its `inner end a stationary turirbolt, this being iitted to lock in a proper slot in the contiguous arranged sectional part F', as indicated in Figs. 3 and 4. The cylindrical stop-valve E', when arranged to abut against the shoulders within the auxiliary cylinder E, forms steam-spaces or chambers G G', (see Figs. 3 anden) in which steam is admitted from the main cylinder, as Will hereinafter appear. In order to guide in its slide motion the stop-valve E lthe same is provided ou top with a groove in which set-screwsfZ are fitted to engage; all lateral or irregular motion onpart of said stop-valve is thus prevented. The duplicate arrangement of steam passages and ports to admit steam from the main cylinder to operate the valve-gear, loe-A fore described, is as follows: The cylindrical stopvalve E' is operated by steam from cylinder A, passing through ports b Z2',- these ports are positioned at the outer ends of said cylinder to communicate by diagonal passages with the steamchambers (5r G of the auxiliary cylinder E, as clearly shown in Figs. 3 and 4. Further, there are similarly arranged the ports c c1 to communi# rrrcn. y

meteen l cate'from' the main cylinder with D- shaped ports from main cylinder passing through ports c 01 c2 c3' c4 c5 into slide-valve cylinder B in an alternate manner, operates its piston` B1 to in ake the reverse stroke required. Also, it will be noticed that by the arrangements of all said parts the cylindrical stop-valve E is operated y alternately'by steam-y power froni main cylinder to admit, exhaust, and cut-off at proper periods the stearnlfrom the rer verse acting slidevalves D The exhaust from the top c-ylinderB is passed through the ports c1 c5, into D-sh'aped ports c2 c3 4of the valve E', from thence out of central exhaust-port c, shownA in Figs. 2, 3, and 4, which leads to main exhaust or escape-pipe. The exhaustfrom'the steam-chambers Gr G of the cylinder E returns and `escapes with exhaust of main cylinderAA.- The direct action of steam passing through the passages arranged `as described and shown is as follows: Supposing the main port a opened to live steam, the ports a3 a1 are opened to exhaust. The piston A1 having nearly finished its; return stroke, steam -port c1 is uncovered, admitting steam through said port into D-s'haped port c3, from thence through p ort or passage c5 into the slidevalve cylinder B, operating its piston B1to the left, which reverses the slide-valves DD. to open the main port a1 to live steam Land the main ports Y a a? to exhaust, (Figs. l and 3;) at the same time the exhaust of cylinder B is escaping through port c1 into D-sh'aped port c2, from thence through central exhaust-port c6 outof the exhaust-pipe.

The piston A1, now ready to commence its for-A ward stroke, uncovers port b admitting steam into the steam-chamber G', (of cylinder E,) reversing it-slstop-valveE to close port c1 to live steam, open ports c5 tG to exhaust, also opening port c to receive live steam as soon as thepiston has passed said port c in its forward stroke. s Immediately, thereibre, as the reverse stroke of the piston occurs, simultaneously occurs' the reverse stroke of the reverse-acting valves, which open exhaustports, allowing escape of the exhaust from one My saidimproved valve arrangements are readilyrepaired, also are not liable to disorder, breakage, or leakage of any of its parts, utilizing the full power of steam, their operation being With less friction and greater power as well as with regularity, precision, and certainty.

Having thus fully described my said improve- 1. The cylindrical stop-valve E formed in sections F F having heads f f1, D-shaped ports c2 c3, when arranged to operate asu and for the purpose set forth.

2. `The arrangement of'auxiliary cylinders B and E, piston B1, double valve-heads' C, reverse slide-valves I) D, cylindrical ystop-valve E', constructed to operate in combination vwith main cylindcr A, substantially as and for the purpose set forth.

3. The' arrangement of steam-passages or ports b b', steam-chambers G G', in ycombination with auxiliary cylinder E an d cylinder A, substantially as and for the purpose set forth.

4. The arrangement of inductive and exhaust ports c c1, D-ports' cz'cs, ports and passages c4115 c, in combination with cylinders E, cylindrie alstop-valves E', and main cylinder A, substantially as and for the purpose set forth.

5. The auxiliary cylinders BE, valves E' D D,

steam-ports c c1 b b c2' c3 c4 c5 c, arranged in coinbination with steam-chest A3, cylinder Ahaving. main ports a a1 a2 a3, piston A1, when all said parts are constructed and arranged to Voperate as and for the purpose set forth.

In testimony of said invention I have hereunto setmyhand.

I JOHN C. MACDONALD. in presence of WILLIAM W. HERTHEL,

ROBERT BURNS. (152) It will be noticed that, as the action of i

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