US2446031A - Semicompound multiple expansion steam engine - Google Patents

Description

July 27, 1948. R. R. WATERMAN 2 Sheets-Sheet 1' lJva F,

v n f 0 r 2 A w R m g a 2 E J U Ml NIH/1| i m VA W It; n m LL r H n w 5 f JJ 3 Patented July 27, 1948 UNITED (STATES PATENT OFFICE -SEMIGO1WPOUND MUL'IIPL'E SION STEAM ENGINE RussllfRJWaterman, Lodi, Calif. "Application'lluly '24, 1944, Serial No. 546,344

3 Claims. (01. 121-103) This invention relates to steam engines, the

main objectheing to provide a steam engine having high and low pressurecylinders, and provided with porting and a controlvalve-arrangement so designed that the engine may be run compound or high pressuresteam fed to the :low pressure cylinder so that the engine will run "simple.

By reason of this arrangement extra starting torque and hence added power may be obtained when desired, as when starting a load, without making the engine unduly large, and retaining the economical advantages of a compound engine when the need for this extra power is not present.

Another object is to. arrange the porting. and control valve so thatthe change in operation of the engine from compound to simple, and vice versa, is effected by merely changing the length ofithe stroke of the v.alve-.-an operation which maybe performed by utilizing any of thecon- 4 ventional types of valve gearing .or linkage such .as are'used to change the valvecut-ofifin conventional engines.

The low pressure cylinder is of the un'iflow type, while the high pressure cylinder isof the counter-flow type; and another object is to arrange the inter-communicating porting, and the control valve, so that tliehigh ressure cylinder becomes the steam measuring cylinder for the low pressure cylinder; thus eliminating the troubles now had with valve actions of such engines when operatin on the extremelyshort cut-offs desirable ta obtain proper'efiiciency therewith. M

In other words, the use of a urfifiow lowflpr essure cylinder automatically eliminates unbalanced pressures between operatin cylinders.

A further object of the invention is to provide a simple and. inexpensive device, and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects I accomplish by means .of such structure and'relative arrangement'of parts as will fully appear by a perusal" of the following specification and claims.

In the drawings similar characterspf refer- 'ence "indicate corresponding parts in the several views: I

Figure 1 is a'ldiagram of my'improved engine showing the pistons at the opposite ends of their stroke, 'and'with the control valve set for simple engine operation.

Figure 2 is a similar view showing the pistons and valve athalf-stroke position. 1

.- Fig ure 3 is a similar viewshowing the valve Js etfor compound engine operation.

2 Figure 4 is an enddiagram of the -enginewith the crank at halts-woke andi'llustratin-g the use of a. conventional type ofval-ve linkage :foracontrolling the setting of the valve.

Referring now more particularly to the char-- actors of reference on the drawings, the engine comprises a high pressurecylinder I and a low pressure cylinder 2, the - cylinders having pistons 3 and 4, respectively, oonnectedby'pistom and connecting rod units 5; as usual, to cranks 6 set i855 apart, so that the pistons travel in; .opposite directions and are at oppositeends of the respective cylinders whens-the cranks tare dead-center position. l A valve chest 1 is mounted anvconnection with the cylinders, having a steam intake ,pipe 8 connected thereto at one endi A hollow-open-ended piston valve 9 is slida-ble in the flohest said valve having a rod l0 projecting from one end thereof and which is connected .to the. control valve linkage ll of any suitable typemountedon the crankshaft, and by means of. whichthe length of the valve stroke orits cut-01f may be altered, so that the valve will move .selected-difierent distances to either side of acentral transverse line H2 in the chest. j

The valve 9 as a whole is of .reduceds'ize elative to the diameter of the chest and includes end pistons l3 fitting the chest and rcentralpistons M also fitting the chest and spaced apart sufficiently to leave an annular channel l5therebetween which communicates withthe intefior of the valve through ports l6.

Steam passages ll communicate with the high pressure cylinder I at its ends and with the chest 1 atsuch points equal distances from the amen-2 as to be closed by the pistons l3 when the valve is in central position, as .shown in. Fig. .2. jfOn'e passage ll,"however, is open to the chest between adjacent pistons l3 and I' l when the valve jiseat the corresponding end of its stroke (whether set for a long ors'hort stroke uncut-0117), while at the same time the. other passage ll communicates with the chest beyond the other endjpfis ton l3 irrespective of the valve stroke, asf'seen by comparing Figs. land '3.

Other steam passages l8 communicate at one end with the ends of the'cylinder 2 and with the chest 1 at. such points equal distances from the line l2 as to communicate with the spaces in the chest 1 just beyond thecentr'al pistons/l4 when the valve is in its central positionyas shown in Fig. 2.

When the piston valve ,is working on along stroke or cut-01f andis at the head-end ofoits stroke, the adjacent head end passage I8 comequal distances from said line I2. Said ports I9, when the valve is in a central position, then open to the chest between the corresponding pistons I3 and I4, as shown in Fig. 2, and the same is true when the piston valve is at either end of its stroke when operating on a short cut-ofi', as shown in Fig. 3. When, however, this valve is'at the head end of its stroke on a long cut-off, the corresponding or .adjacent port I9 is still open to the chest between the adjacent valve pistons, but the other port I9 is closed by the other end piston I4, as shown in Fig. 1. An exhaust pipe 28 leads from the cylinder 2 centrally of its ends or so as to be uncovered when the piston 4 is at either end of its stroke.

I I In operation, when it is desired to operate the engine simple, as when starting a load, the valve 9 is set for a long stroke by suitable manipulation of thelinkage I I. The cranks 6 are set relative to the valvelinkage so that when the valve is at the head end of its stroke, for instance, the piston 4 is at the head end of its cylinder, while the pistons is at the opposite end. Steam admitted to the chest I from pipe 8 then passes directly through the valve 9 to the ports I6 and into the channel I5, entering the head end passage I8, whicli then communicates with said chest, and then flows into the head end of cylinder 2 on top of the piston 4, as shown in Fig. 1, the other passage I8 being then idle.

At the same time steam is entering cylinder I atits opposite end through the corresponding passage H, which is open to the chest beyond the valve. Said head end passage I8, however, also communicates with the head end of cylinder I through the adjacent port I9, the chest I between adjacent pistons I3 and I l, and the ad jacent passage H. The steam pressure in cyl inder I is therefore balanced and the piston 3 then, does little work. Steam taken into said cylinder at its. head end, however, is forced into the cylinder 2 in a measured amount as. the piston 3 moves toward the head end of the cylinder until, the passage I1 is cut off by the adjacent valve piston I4. When the piston l reaches the end of its stroke the steamexhaust through the pipe and fresh steam is then admitted to the opposite end of cylinder 2 in the same manner as above described, for thereturn stroke. The cylinder 2 is then operating on high pressure steam, as will be evident, and, due to the large size of the piston I, exerts great starting torque on the crankshaft. When the need of this extra torque haspassed, the valve linkage I i is manipulated to set the piston valve on a short stroke. .With the valve then at the head end of the chest,

steam enters the lower end of cylinder I as before and passes out from above the piston 3 through the head end passage H, which then communicates with the chest 1 between the adj-acentvalve pistons I3 and I4. I he head end port I9, however, is also in communication with the chest between said pistons so that the previously expanded steam flows directly from cylinder I above the piston 3 into cylinder 2, so that the latter then operates compound. When the cylinder pistons and valve reach the opposite ends of their stroke the spent steam in cylinder 2 passes out through pipe 20, and the entering flow of steam to said cylinder is of course reversed.

The engine may be operated partially simple by the use of amedium valve stroke; and the same engine. operation and functioning may of course be obtained when the cylinders are disposed in a tandem relation.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention asset forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described my invention, what I claim as new and useful and desire to secure by Letters Patent is:

1. A steam engine comprising a, counterflow cylinder and a unifiow cylinder having an exhaust port, a steam chest connected to a source of steam, steam. passage means between the cylinders and chest and including the latter, and a valve adjustable as to length of stroke, movable in the chest and cooperating with the passage means to feed steam from the chest to one end of the counterflow cylinder and from the opposite end of the latter to the uniflow cylinder; or to feed steam from the chest to both cylinders simultaneously and depending on the length of stroke of the valve.

2 A steam engine including high and low pressure cylinders having pistons arranged for reciprocation in opposite directions, a steam chest connected to a source of steam, a, valve manually adjustable as to length of stroke mounted for reciprocation in the chest, and means forming steam passages between the ends of the cylinders and the chest and communicating with the latter in such relation to the valve that said valve, when operating on one stroke length will cause steam to feed from. the chest to one end of the high pressure cylinder and from the other end of the latter to the corresponding end of the low pressure cylinder; and so that said valve, when operating on another stroke length, will cause steam to feed direct from the chest to both cylinders at opposite ends thereof simultaneously, as well as to the same end of the low pressure cylinder from the other end of the high pressure cylinder. V

3. A steam engine comprising a counterfiow cylinder and a uniflow cylinder, a piston mounted in each cylinder said piston being operable to move alternately in relatively opposite directions, respectively, each of said cylinders being provided with an intake port at each end thereof andthe uniflow cylinder being provided with an exhaust port substantially mid way of its length, a steam chest, means for connecting the steam chestto a source of steam supply, a slide valve operable within the steam chest, said valve, when in one position, opening communication from the steam chest to both ports in the counterflow cylinder and to one port in the uniflow cylinder, simultaneously, and said valve, when in another position, opening communication from the steam chest to the port in one end of the counterfiow cylinder and from the port in the opposite end of said counterflow cylinder to the port in the corre- Number sponding end of the uniflow cylinder. 707,647 RUSSELL R. WATERMAN. 1,165,579 1,512,205 REFERENCES CITED 5 1,746,104 The following references are of record in the file of this patent. Number UNITED STATES PATENTS 2 4, 7 Number Name Date 10 387,426

511,016 Hansel Dec. 19, 1893 Name Date Schneider Aug. 26, 1902 Ditsler Dec. 28, 1915 Ellis Oct. 21, 1924 Christiansen Feb. 4, 1930 FOREIGN PATENTS Country Date Great Britain Dec. 22, 1927 Great Britain Feb. 9, 1933

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