US223663A - wheeleb - Google Patents

Description

6 Sheets-SheeLl N. W. WHEELER. Pumping-Engines. No. 223,663. Patented Jan. 20,1880.

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Pumping-Engines. No. 223,663. Patented Jan. 20,1880.

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No. 223,663. Patented Jan. 20,1880.

N.PETERS. PHOTO-LITHOGHAPHER WASHINGYON. D C,

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N. W. WHEELER.

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UNITED STATES PATENT OFFI E.

NORMAN W. WHEELER, OF BROOKLYN, NEW YORK.

PUMPING-ENGINE.

' SPECIFICATION forming part of Letters Patent No. 223,663, dated January 20, 1880.

Application filed June 9, 1879.

To all whom it may concern:

Be it known that I, NORMAN W. WHEELER, of the city of Brooklyn, county of Kings, and State of New York, have invented a new and useful Improvement in Pumping-Engines, of which the following is a specification, reference being had to the accompanying drawings, in which Figure I is a front elevation. Fig. II is an end elevation. Fig. III is a rear elevation; Fig. IV, a diagram illustrating the action of the engine; Fig. V, a sectional View of the steam-valves and adjacent parts; Fig. VI, a plan of the steam -chest with the cover removed to show the valves and their attachments; and Fig. VII, a front View of the initial and expansion cylinders, showing the arrangement of the main steam ports and passages.

This invention relates, chiefly, to compound steam-engincst'. 6., engines in which the steam works first in one cylinder and then passes to a larger cylinder, wherein it works by expansion previous to its final release; and it consists, chiefly, in devices for connecting the pistons to a beam, a crank, and to a pump or pumps, whereby peculiar relative movements of the pistons are secured; and, further, in devices for the prevention of steam-cushions, for the proper distribution of steam, for avoidance of loss from idle expansion of steam, and for combining pumps with such engines.

A is the main frame of the engine; B, the crank; G, the initial steam-cylinder, with the steam-chestE; D, the expansion-cylinder; F, the beam, mounted upon the beam-center P in the plumber-frame G; I, the piston-rod of the expansion-cylinder D; R, the piston-rod of the initial cylinder; J, a link connecting I directly with the beam F, and L a link connecting R indirectly withthe opposite end of the same beam F.

N N are two single-acting plunger-pumps U U, the plungers, and K K links connecting the plungers U U with the beam F.

O is a cross-head guide; S, a small diskwheel upon the shaft, which is mounted in bearings upon the frame A, and carries the crank B, together with a return-crank-and eccentric-pin, to actuate the eccentric-rod d, rocker-arms e, and valve-rod f.

H is a deltoid frame, which carries the bearings 00 b c, a taking a pin near the end of the beam F, I) a pin in the link L, and c the wristpin of crank B. y

The side a 0 of the deltoid frame H forms a straight connecting-rod between the beam-pin and the crank-pin, so that the relative movements of the crank-pin andthe piston of the expansion-cylinder D are similar to those of the common beam -engines; but the initial piston upon the rod R has a different movement because of its connection to the deltoid frame H at the point b, as is shown in the diagram -Fig. IV, wherein the circle B b traversed by the crank-pin is marked at twentyfour equidistant points, and each point numbered. The paths of the beam-pins I z', J j,

E e, and Ff are marked and numbered correspondingly, and also the path .0 'c D d of the deltoid-frame pin 1).

It Will be seen upon inspection that the expansion-piston reaches the end of its stroke at No. 1 in one direction and at No. 13 in the other, while the initial piston reaches the end of its stroke later, near Nos. 3 and 15, and that during the earlier parts of a stroke the initial piston has a rateof motion considerably less than that of the expansionpiston at the same time, and that these relative rates of motion are reversed in the later portions of the stroke of the expansion-piston.

The different times of ending their strokes and the varying rates of motion of the pistons of a compound engine connected and asso ciated with a crank, as before described, make the engine especially valuable for pumping purposes, because during the earlier parts of a beam or pump stroke the great pressure upon the expansion-piston is sutficient of itself to do the required work with but little assistance from pressure upon the initial piston but in the later parts of a pump-stroke the decreased pressure upon the expansion-piston by reason of the expanded state of theisteam within the cylinder is supplemented by a greater effect derived from a nearly constant pressure upon the initial piston, the increase of effect being indicated by the relative increase of speed of the initial over that of the expansion piston, so that a persistent or even increasing pressure may be put upon fluids acted upon in the pump or pumps N N from near the beginning to the end of the stroke.

The action of this engine may be described in another way. Thus, when the crank B starts from a vertical position in line with the pin of bearing a, and moves from No. 1 to No 2 and beyond, the effect is to tilt the deltoid frame H so that the pin of b rises faster than the pin of to falls, and that as motion is continued the pin of b rises absolutely until position 3 is passed, when the upward motion of b arising from the tilting of the deltoid frame H is overcome by the downward motion of a, and then the initial piston begins its downward stroke; but until the crank-pin of B reaches nearly the half-stroke the tilting of H goes on, and the motion of the initial piston is thereby retarded and made less effective than it would otherwise be, the deltoid frame H, crank B, and beam F acting as a combination of toggle-levers with the beam-center P and shaft of B as fulcra, the system being opened by force acting downward at I), while the resulting side pressure upon the crank-pin resists the opening of the system; but after the half-stroke is passed the deltoid frame H is tilted back toward its original vertical position, and the resulting side pressure upon the crank-pin assists the closing of the system of toggle-levers, and the effect of the pressure upon the initial piston is thereby augmented, at the same time that the effect from pressure upon the expansion-piston is small by reason of the expanded state of the steam then 0011- tained in the expansion-cylinder.

In the example before us the distribution of steam is elfected in the steam-chest E by means of the main valve 9 g, Figs. V and VI, having two exhaust-cavities, motion being given thereto by means of a return-crank, eccentric-pin, eccentric-rod d, rocker-arms e, and valve-rod f.

The valve-seat is common for the two cylinders, and has the initial ports or passages 02 n, intermediate ports 1) o, and exhaust-port t, which opens into the exhaust-pipe w. The passages an lead from the intermediate ports a 'v to the respective ends of the expansioncylinder D.

The valve g g has a considerable lap over the initial ports a a and very little lap over the intermediate ports 1; o and the exhaustport t. The different laps over the different ports correspond with the lead that the expansion-piston has over the initial piston, and secure the taking of intermediate steam into the expansion-cylinder and the final exhaust therefrom at the proper times, and also secure the taking of initial steam into the initial cylinder at the proper time, as well as the cutting off of the initial steam before the intermediate exhaust takes place, so that for any stroke initial steam passes into the initial cylinder through a port, a, is cut off before the intermediate exhaust occurs; then, by reason of the continued movement of the valve g g, the way is opened through a 9 U u for the intermediate steam to pass to the expansion piston at the time the stroke of the expansionpiston is completed and before the completion of the initial piston-stroke, both pistons moving for a short space in the same direction from the force of expanding steam, which delivers the sum of the pressures to the beam F; but so soon as the initial piston begins its return-stroke, the pistons then moving in opposite directions, the force delivered to the beam F from expanding steam ,is that due to the pressure upon the expansion-piston minus the back-pressure upon the initial piston; but this force is supplemented by the pressure of initial steam upon the initial piston.

When the expansion-piston terminates its stroke the final exhaust takes place from the expansion-cylinder D through a o g t w, and a charge of intermediate steam is received through the opposite ports and passages a a u.

The motion of the valve g g relatively to that of the pistons of the cylinders G and D is illustrated in Fig. IV. At B b is seen the throw-curve and lap-lines for the cylinder 0, and those for cylinder D are seen at A a, the numbered ordinates representing the relative positions of the respective pistons in each case.

To avoid the compression of intermediate steam before the initial piston after the closare of the port a by the inside lap of the valve g, the passages 0 0 are provided, which open into the cavities ll in two transverse slidevalves, h h, mounted upon the back of the main valve 9 g, and from these cavities l l the escape-ways are continued through the passages a a into the exhaust-cavities of g g.

There are lips m m, within the cavities l l, to open and close the ports a a by the transverse movements of the valves h h. The pressure of live steam upon the valves h It holds them to their seats.

The valves h h are connected by a bar, t', mounted upon the pin 3' fixed in the valve 9 g, and the bar 41 is extended to one side and the extension notched, so as to be actuated by a tappet-pin, w, fixed in the steam-chest cover, all in such a way that, when the valve 9 g approaches the end of its throw, contact of the sides of the notch of the bar i with the tappetpin on causes the valves h h to be moved, so that the passage a at the end of the valve g g, which has last cut off initial steam, will be opened and the opposite passage closed to allow the escape of intermediate steam'from before the initial piston after the port a shall have been closed by the normal inside lap of the valve g g, the cushion escape being through 0 l a to the exhaust-cavity of g g.

While the cushion escapes, as above described, the opposite passage a is closed by the lip m of the valve h, and a premature intermediate exhaust prevented. Thus the lap and lead for the purposes of expanding initial steam in the usual way are retained, while the effects of inside lap are abolished at the time it would cause retarding compression of steam.

This device for cushion release is applicable to the common sort of slide-valve engines, wherein the designer has been compelled'to compromise between undue compression and Iio undue exhaust lead, or resort to a more or less complicated independent cut-off gear.

'It will be observed that the final exhaust from the cylinder D occurs before the initial piston completes its stroke and while the valve h is open, so'that, if there be a vacuum in the pipe to and beyond, it will extend through tn 1 0 it into the space before the advancing initial piston, which would otherwise be occupied by a retarding steam cushion. The vacuum tends to re-enforce the effect upon the pumps N N near the end of a stroke.

It will also be observed that, although one piston leads the other over the centers, no intermediate chamber is requisite, such as is used in common compound engines, with one piston leading the other over the centers, because no perceptible retarding cushion is formed before advancing pistons. Therefore the waste from idle expansion is reduced to that due to clearances and short passages only.

When the duty of the engine is to be that of compressing elastic gases or vapor, involving an increase of resistance as a stroke progresses, the conditions are met by increasing the distance a I) relatively to the distance a c, as hereinbefore indicated, by making the cylinders more nearly of equal contents than would otherwise be judicious, and by working initial steam in both cylinders, the several proportions being determined by the elasticity of the gas or vapor and the amount of compression 7 to which it will be subjected.

The capacity for delivering increased pressures upon the pump-plungers as a stroke progresses may be augmented by using two sin gleacting pumps, as N N, and attaching them to the beam F by pins, not both in the same right line drawn through the beam-center P, but upon lines diverging therefrom toward the pumps, or by inclining the pumps relatively to the beam, so that the pump-connection pins will sweep through a greater rectilinear distance in the earlier than in the later parts of the stroke.

The devices herein described may be varied in many ways. For example, piston or puppet valves may be substituted for the slide-valves,

'stead of one eccentric.

which valves may be actuated by several in- The pump or pumps may be attached to one of the piston-rods, and

radius or parallel-motion bars be substituted for the beam F. An imperfect imitation of the relative movements of parts and of the action of the engine may be made by connecting each piston -rod with a crank which leads or follows another upon the same shaft; but in this last supposed case the peculiar slow relative motion of the initial piston in the early part of the stroke and the faster motion in the later parts of the stroke exhibited by the engine herein specifically described would be lacking in a great degree.

' All such like formal variations in compound pumping-engines in which steam is used expansively in two cylinders, and which deliver a constant or increasing pressure to the pump from near the beginning to the end of thestroke without the use of an intermediate chamber, I regard as falling within the scope of my invention.

I claim-- 1. Two cylinders, G D, and their adjuncts, working as a compound engine without intermediate chamber, and one piston leading the other over the centers, in combination with the pump or pumps N N, substantially asand for the purposes described.

2. The pistons of the cylinders G and D, in combination with the deltoid frame H, crank B, and pump or pumps N N, substantially as and for the purposes described.

3. In compound engines so constructed that the expansion-piston leads the initial piston over the centers, the ports and passages a n, o v, u u, and t, in combination with the valve 9 g, substantially as and for the purposes described.

4. The relief slide-valves h h, with means of actuating the same, in combination with the valve 9 g, substantially as and for the purposes described.

NORMAN W. WHEELER.

Witnesses:

ABNER VAN HORN, JOHN F. RoBER'rs.

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