US356376A - Valve mechanism for compound engines - Google Patents

Description

(No Model.)

F. M BITES. VALVE MECHANISM' FOR COMPOIUNDENGI-Ns.

Patented Jan. 18 1887.

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Unire STATES ArnNr erica.'

FRANCIS M. RITES, OF PITTSBURG, PENNSYLVANIA.

VALVE MECHANISNI FOR COMPOUND ENGINES.

SPECIFICATION forming part of Letters Patent No. 356,376, dated January 18, 1887.

Application filed September 27, 1886. Serial No.2i4,592. (No model.) 4

To all whom, it may concern:

Be it known that I, FRANCIS M. BITES, residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, a citizen of the United States, have invented or discovered acertain new. and useful Improvement in Valve Mechanism for Compound Engines, of which improvemcntthe following isaspeciication.

The object of my invention is to enable the admission of steam from the high-pressure to the low-pressure cylinder of a compound engine to be effected by a single eccentric at the proper period of the piston-stroke to attain a high degree of expansion in the low-pressure cylinder without the corresponding undue compression in the high pressure cylinder incident to the operation of valve-gears as ordi,- narily heretofore constructed. f

To this end my invention, generallystated, consists in the combination, with a steamen gine, of a sectional distribution-valve, the sections of which govern the passage of steam through different ports, respectively, and which are independently coupled to the strap of a valve-operating eccentric at different distances from the center thereof.

The improvement claimed is hereinafter fully set forth.

In the accompanying drawings, Figure 1 is avertical transverse section through a compound engine embodying my invention, taken at the center of the valve-chest; Fig. 2, a vertical longitudinal central section through the valve-chest, and Fig. 3 a horizontal section through the same at the line x x of Fig.'2.

The engine to which my improvement is herein shown as applied is of the vertical single-acting type, having a high-pressure cylinder, 1, and a low pressure cylinder, 2, of larger diameter, fixed side and side upon the top of a crank caseor boX, 3, and fitted with pistons coupled by connecting-rods in the ordinary manner to the pins of cranks set 0ppositely or one hundred and twenty degrees apart on a crank-shaft, 5, rotating in end bearings in the crank-case 3. Steam is admitted to and exhausted from the high and low pressure cylinders by a distribution-valve reciprocated by an eccentric, 13, in a sleeve or bushing, 11, Xed in a valve-chest, 12, located between the cylinders and provided With a se` ries of steam-supply ports, 17, communicating with a steam-supply passage, 16, to which the .main steam-pipe from the boiler is connected,

a series of high-pressure ports, 18, above the supply-ports 17, said high-pressure ports communicating with the piston-space of the highpressure cylinder, a series of low-pressurek ports, 24, above the high-pressure ports communicating with-the pistonspace of the lowpressure cylinder, and a series of exhaustports, 25, above the low-pressure ports, communicating with an exhaust-passage, 26 to which an exhaustpipe,leading into the atmosphere or to a condenser, is connected.

' The eccentric 13, which actuates the distribution-valve, is preferably, as in the instance shown, mounted adjustably upon the crankshaft, so as to be varied and controlled in position by a centrifugal governor of any suitable construction, the governor illustrated being similar to that which is set forth in an application for Letters Patentfiled by me September 1, 1886, Serial No. 212,351, and not constituting part of my present invention.

The distribution-valve by which admission separate and independent sections, 3 4, each having an upper and a lower piston connected by a body of smaller diameter, so as tol provide an annular space between them for the passage of steam from one to another series of ports of the valve-bushing 11, and both being coupled to the strap 19 of the eccentric 13, so as to be reciprocated therewith and thereby, but in ,suchv manner, as presently to be described, that the valve-sections, while moving coincidently in the same direction, shall likewise have independent relative movements and exhaust are'effected is composed of two and different degrees of traverse, and are all ternately caused to approach and recede from each other through a limited degree of traverse in their upward and their downward movements respectively.

The admission of steam to the high-pressure cylinder is effected by the upper piston of the lower valve-section, 3, the exhaust of steam from the high-pressure cylinder to the lowpressure cylinder by thelower piston ofthe upper valve-section, 4, and the exhaust of steam from the low-pressure cylinder to the exhaust- ICO passage 26, between the lower and the upper pistons of the upper ValvesectiOn, 4. It results from such construction and function of the valve-sections that if they be drawn more closely together on their upward traverse and moved farther apart on their downward trav erse, and the upper section be given a greater traverse than the lower section, a hetter portopening on both admission and exhaust anda later exhaust will be attained for the lowpressure cylinder, thus affording a higher degree of expansion, and compression will he made later in both cylinders, all of which tend to a more economical utilization of steam.

To impart the movements above referred to to the two valvesections from the eccentric 13, I provide the lbllowing mechanism: rEhe 'upper end ot' the eeccntriestrap 19 is caused to move in a substantially-vertical line by being coupled to a fixed bearing, 29, on, the eranl case by meausof apair of links, 27. iournalcd at one end on a pin, 28, iu the bearinfr 29, and

' at the other on a piu, '23, in the upper end of the eecentricfstrap. The lower valve-section, 3, is coupled by a pair of links, 22, to the pin 23, and a lateral projection, 141-, formed upon the upper` end of the eccentric-strap 19, substantiallyr at right angles to a line drawn from the center of the eccentric to the center of the pin 23, carries a pin,2l,whieh is coupled by a link, 20, to a pin on the lower end ot' a stem, 6, passing freely through the lower valveseetion, 3, and secured to the upper valve-sec tion, 4. The effect of such lateral connection ofthe upper valve-section to the eccentricstrap is toimpart to said section a movement corresponding to that which it would receive from an eccentric of greater throw and less angular advance than the eccentric 13, as well as to retard in both directions the movement of the upper section, l, relativelyto that of thelower section, 3, due to its connection with the strap in or substantially in line with the center thereof, thereby giving an increased traverse to the section I relatively to the section 3, and causing its distance from the section 3 to be decreased on the upward stroke and increased on the downward stroke of thc valve, the advantageous results of which difference of traverse and variation of relative position have been hereinbefore stated. A

I claim as my invention and desire to secure by Letters Patentl. rlhe eombiuatiomin a stearn-engine, of a distribution-valve composed of two separate and independent sections which govern, respectivel y, the passage of steam through dift'en ent ports, and are independently coupled at different points to the strap of a single operating-eccentric, substantially as set forth.

2. The combination, in a steam-engine, of a distribution-valve composed of two separate and independent sections which govern, respcctiv ely, the passage ot'steam through different ports. a single operating eccentric and strap, and link-connections in and ont of line, respectively, with the center oi" the eccentricstrap, and coupling the valve-sections independently thereto, substantially as set forth.

3. The combination, with a compound engine having a hi gli-pressure and a low-pressure cylinder, of a valve-chest having a port or ports leading to the high-pressure cylinder, a port or ports leading to the low-pressure cylinder, and a port or ports leading tothe exhaust, a distribution-valve composed ot two separate and inde pendent sections, the high pressure section ot' which governs admission and exhaust ot' steam l to and from thehigh-pressure ports, an d the lowpressure section admission of steam from the high-pressure to the lo\vpressure ports and exhaust from the low-pressure to the exhaustports, an operating eccentric and eccentric- `strap, and links coupling the higlrpressure

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