US957762A - Slide-valve motion for steam-engines. - Google Patents

Description

E. FRIKART. SLIDE VALVE MOTION FOR STEAM ENGINES.

APPLICATION FILED MAY 23, 1908.

Patented May 10, 1910.

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APPLICATION FILED MAY 23, 1908.

Patented May 10, 1910.

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EUGEN' FRIKART, or MT'J'LHAUsEN, GERMANY, ASSIGNOR TO nLsiissIsoHE MASGHINENBAU-GESELLSGI-IAFT, or Mt'ILHAUsEN, GERMANY.

SLIDE-VALVE MOTION FOR STEAM-ENGINES.

Specification of Letters Patent. Patented May 10, 1910,

Application filed. May 23, 1908. Serial No. 434,622.

To all whom it may concern:

Be it known that I, EUGEN FRIKART, a citizen of the Swiss Republic, residing at Miilhausen, Alsace, Germany, have invented certain new and useful Improvements in Slide-Valve Motions for Steam-Engines, of which the following is a specification.

The invention relates to a slide-valve motionfor steam engines, the actuating device of which requires only one half the number of revolutions made by the crank-shaft of.

the engine; thus during a complete revolution of the crank-shaft the actuating device rotates only to the extent of 180, or, in other words, during the time that the piston changes its direction twice in the steam cylinder, the slide-valve does so but once. In the case of ordinary slide-valve motions and piston slide-valve motions only one and the same edge always acts, that is to say that, when the slide-valve moves in the one or the other direction, its one edge opens and closes the inlet passage, the other edge of the slide-valve never passing above this passage. Under the conditions existing in the present invention, and given by the actuating device, the two edges of the slide-valve alternately open and close the inlet passage, as, when the inlet-valve moves in the one direction one of its edges opens the inlet passage, its other edge closing the same, while when the inlet-valve moves in the opposite direction precisely the reverse takes place that is to say, the latter edge opens and the first mentioned edge closes the passage. It is exactly the same with the outlet valve. In order that, under the action of the governor of the engine, it may be possible to vary the admission of steam to the engine fitted with such a valve-motion, the slide valve for the admission of the steam, at least, is divided and the arrangement so carried out that the two parts of the same can not only be actuated together, but that, if the quantity of steam-admitted to the engine is to be varied, each part acts independently, that is to say, can be brought nearer to or put farther apartfrom the other.

Figure 1 of the accompanying drawing illustrates the present invention in the form of a piston-valve motion, by way of example, in cross section. Fig. 2 illustrates, also by way of example, anarrangement of the device for actuating the inlet and outlet valves and for adjusting the two parts of the inlet valve. Fig. 3 shows diagrammatically this latter device in another position.

The cylindrical admission valve box f which has a passage e, through which the steam passes to the steam cylinder, contains two piston slides one behind the other. The slide a is attached to a rod 8, the othera is secured to a sleeve 1) surrounding the rod 8. The other end of the rod 8 is connected by a link 0 with the one end of an oscillating arm a, which is loosely pivoted on a shaft 2 actuated by the sleeve of the governor. The other end of the oscillating arm n is pivoted to a link g, which is flexibly connected with a rod Z pivoted to the strap of the eccentric w. The hollow rod Z) of the slide a" is connected by means of a link d with the one arm h of a crank lever pivoted to the oscillating arm n,- to the other arm h" of the crank lever is pivoted a link rod 2', which is pivotally connected with one arm of a double-armed lever 70 firmly secured on the already mentioned shaft 2 actuated by the governor-sleeve. To the other arm of the lever is is pivoted a rod m which is pivotally connected with the rod Z connected to the strap of the eccentric m. The arrangement of the levers h and 7c, the link 2' and the upper portion of the oscillating arm n is such as to form a parallelogram, as shown in Fig. 3.

The exhaust slide-valve box f has a passage 1) leading from the steam cylinder, and contains two slides a, a, one behind the other, which however are firmly secured to one and the same rod 6, at a distance apart corresponding to the length of the passage 0. The rod t terminates in a cross-head p, to which is connected a rod 1" linked to one arm of an angle-lever g rotating around a fixed center 0. To the other arm of the angle-lever g is pivotally connected the eccentric-rod 3 In the position of the admission valves a and a shown, the latter keeps the inlet passage 6 closed. During one half revolution (from the position indicated into the opposite one) of the controlling shaft with the eccentric as, which in accordance with what is set out in the introduction, corresponds to a complete revolution of the crank-shaft, the two valves a and a move to the left, without stopping and without change of direction, to such an extent that the inlet below slide, a or a )assa e e is first uncovered b T the slide a l a and then completely covered by the slide a. In this case the uncovering is effected by the edge 2 of the valve a, the covering being effected by the edge 1 of the valve a. During a second complete revolution of the crank-shaft and during the second half rotation of the controlling shaft the two slides a and a move back into the starting position as illustrated without stop Ding on the way or altering their direction of movement. In this case the slide edge 1 'efiects the uncovering, and the slide edge 2 the covering, of the inlet passage 0. Thus in fact there is a change in the direction of movement of the two slides a, a only half as frequently as in that of the steam piston.

The ordinary regular movements of the slides a and a forward and backward are effected by the arm a oscillated around the shaft 2 by the rod Z connected to the strap of the continuously rotating eccentric :0, but the time during which the inlet passage 6 wholly or partially opened, can be shortened or lengthened, the distance between the two slides a and a being reduced or increased for this purpose. In consequence of this, the slides a and a are axially displaced in opposite directions, the former through the media of the parts m, g, 12., c and a, and the latter through that of the parts 2', h, h, (Z and Z), and an alteration of the position of the rod Z to that of the eccentric-strap takes place. This alteration has however no influence onthe point where the rodZ is attached to the eccentricstrap, he effect of it being firstly an alteration of the position of the oscillating arm n and a slight displacement of the slides a and a, both in the same direction in relation to the inlet passage e, and secondly a vaiiation of the length of the are passed by said point on its curve. Upon the length of said arc depends the degree of the steam-admission. According to the position of the governor-sleeve or above its middle position, the distance of the edge 1 of the slide a from the edge 2 of the slide a varies with the various positions of the two arm lever is, the closer the two edges 1 and 2 are, the shorter the time the inlet passage to the steamcylinder is uncovered, and vice versa. The timely uncovering of the inlet passage, for the purpose of insuring the advance motion or outsidedead, by the one or other is always efiected at the same position of the piston in the steam-cylinder, whatever be the degree of steam-admission and notwithstanding a relative motion of the slides one to the other with a regulating motion of the governor-sleeve.

As to the exhaust valve u, u", it is at the first half revolution of the controlling shaft with the eccentric m moved air of the position shown to the left; the edge 2 effects the uncovering and the edge 1, the covering of the outlet passage '0 of the slide box f, while at the second revolution of the controlling shaft the edge 1 efiects the uncovering and the edge 2 the covering of the passage 0).

Obviously each, the inlet and the outlet slide, may have its own eccentric, and these eccentrics may be adjusted on the controlling shaft corresponding to a certain condi tion of working best suited to the distribution of the steam in the cylinder. If, as for example in the use of a low-pressure cylinder of a compound engine, an alteration of the steam admission under the action of the governor be not necessary, the slides for the inlet and outlet need not be divided, each forming in itself a single piston with openings in certain places in its sides. In this case several passages for the inlet and the outlet of the steam may be provided on the slide face. The width of the openings and their distance apart are taken according to the width and the distance apart of the passages in the slide face. v

lV hat I claim as my invention and desire to secure by Letters Patent is 1-. In a slide valve motion for steam engines the combination with an eccentric, and eccentric strap, and a controlling shaft on which said eccentric is mounted, of an admission slide-valve divided into two parts a (4 adapted to move independently of each other, an oscillating arm operated by the said eccentric and connected with part a, of the slidevalve, a shaft 2 on which said oscillating arm is loosely mounted, means for operating said latter shaft, a crank-lever pivoted to said oscillating arm, a double= armed lever secured on shaft 2, a parallel link mechanism connecting one arm of said double-armed lever with the said cranklever, and means connecting the other arm of the double-armed lever with the eccentric strap. v A

2. In a slide valve motion for steam engines the combination with an eccentric, and a controlling shaft on which said eccentric is mounted, of a divided admission slidevalve the parts of which are adapted to move independently of each other, and means for operating said parts of the slidevalve for the purpose of varying the degree of admission to the steam cylinder.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EUGEN FRIKART;

\Vitnesses:

' HANS FRIOKELBERGER,

GEO. GIrroRD.

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