US199865A - Improvement in piston-valves - Google Patents

Description

W C. Ross. Piston-Valve.

1510.199865. Patented Jan. 29, 187s.

jig. f.

N. PETERS. FHOTOYLITHOGHAFHER, WASHINGTON. D C.

UNITED' STATES' PATENT OFFICE-L VVILLIM C. ROSS, OF CINCINNATI, OHIO.

IM PROVEM ENT IN VP|STON VA| 'VES.

Specification forming part of Letters Patent N0. 199,865, dated January 29, 1878; application filed l December 18, 1877.

ton-valve,.0f an auxiliary piston-valve, which mechanically starts the main valve in shifting, and also governs the ports through which steam is introduced and exhausted, to complete the movement of the main valve.

It further consists in so constructing the v valve that the piston-heads of the auxiliary valve serve to conine the steam admitted to the valve-chest, so that the latter may be constructed without heads, and thus admit of the withdrawal of the valves at any time for examination and repairs without disturbing` any joints.

In the annexed drawings, Figure l is a sectional elevation of my improved piston-valve, showing` its application to a steam-pump. Fig. 2 is a plan of the valve, showing the whole of the chest and one-halfof the valves in section. Fig. 3 is a front elevation of the same. Fig. 4 is a transverse section.

The' same letters of reference indicate identical parts in all the gures.

The valve-chestA has a central bore or valvel chamber extending entirely through it from end to end. In this instance, the valve-chamber is of uniform diameter throughout. The several piston-heads of the main and auxiliaryvalves are snugly itted therein, the heads B and Bl of the auxiliary valves rigidly secured to or formed on the stem B2, being provided with glands C and C and suitable packing, to vform tight steam-joints. The heads of the auxiliary valve are provided with recesses or annular grooves b and b', respectively, which communicate through holes c and c with the valvechamber. The main valve is fitted to slide on the stem B2, between the heads of the auxiliary valve, and consists of three heads, D, D1, and D2, imited by hubs, or in any other suitable manner, so as to move together.

The diiference between the length of the main valve and the distance between the heads -throw of the main valve.

of the auxiliary valve is determined by the On one side of the valve-chamber the chest is provided with a steam-chamber, E, and ou the other side with an -exhaust-chamber, F. The steam-chamber E communicates with the valve-chamber through the main steam-ports e and el, which are con. trolled by the heads D and Dl of the main valve, and also through the auxiliary port-s c2 and e2, which are controlled by the heads of the auxiliaryvalve. The exhaust-steam from the cylinder passes from the valve-chamber to the exhaust-chamber F through the main exhaustport j', governed by the head D2 of the main valve, and the steam utilized in shifting the main valve escapes to the exhaust-chamber alternately through the auxiliary exhaustports f1 and f2, which are controlled by the heads of the auxiliary valve. 'Ihe cylinderports G and Gr of the chest lare on opposite sides of the head D2, and are controlled by the heads D and Dl of the main valve.

The valve-stem B2 carries tappets B3 andB,

which are alternately struck to initiate the shifting of the valve by an arm, H, on the main piston-rod I of the engine, just before the piston completes the stroke.

The operation of the valve is as follows: In the position of the valve shown in Fig. 1, the main steam-port eis uncovered, so thatlive steam enters the cylinder through portG, and drives the piston from left to right. Of the auxiliary steam-ports, e2 is closed and e3 open, while of the auxiliary exhaust-ports, f1 is open and f 2 closed, so that the main valve is held against the head B of the auxiliaryvalve by the pressure of the steam between the respectivel heads Bl and D1 of the said valves. Just before the main piston of the engine completes its stroke in this direction, the arm H on its rod strikes the tappet B4 on the valve-stem B2, and moves the auxiliary valve far enough by the time the stroke is completed to cover auxiliary Vsteam port e3 and uncover auxiliary steam-port e2. At the same time the auxiliary exhaust f2 is uncovered, to admit of the escape of the steam confined between the respective heads Bl and D1 of the valves, and the auxiliary exhaust-port f1 is covered. The main valve is also pushed to the right by the head B of the auxiliary valve by the 4same movement, and

begins to cover main steam-port c, without, however, uncovering as yet main steam-port el, which is not effected until the main valve is further moved by the pressure ofthe steam behind its head D,whereby it is iinally thrown against the head B1 of the auxiliary valve, so as to close port e and establish communication between ports el and G at the same time that communicationis openedbetween G and ports f. The cylinder-ports G and Gr are always open, and in shifting the valve its open main steamport 'remains open until the main valve is moved by steam-pressure. The engine will therefore start from any point in the stroke.

The initiatory mechanical impulses given by the auxiliary valve to the main valve in shifting will prevent any sticking of the latter.

What I claim as my invention, and desire to secure by Letters Patent, is-

l. In a piston-valve, the combination, substantially as specified, of the main valve, the movement of which in shifting is initiated mechanically and completed by steam, and an independent auxiliary valve, which is moved mechanically only, merely starting the main valve `and reversing the ow of the steam acting thereon.

2. In a piston-valve, the combination, substantiallylas specified, of an independent auxiliary valve, moved mechanically only, and a main valve tted to slide between heads of the auxilary valve, which mechanically initiate the movement of the main valve in shifting, besides controlling the ports through which steam enters to complete such shifting of the main valve.

3. The combination, substantially as specitied, of the triple-headed main valve, the cylinder-ports, the main exhaust-port, the main steam-induction ports of the valve-chest, the double-headed auxiliary valve, whose heads are provided with steam-passages, and the aux- :iliary steam and exhaust ports of the valvechest.

4. The combination, substantially as specied, of the open-ended valve-chamber, the double-headed auxiliary valve, and the main valve confined between the heads of the auxiliary valve, so that both valves can be drawn together endwise from out of the open-ended valve-chamber.

In testimony whereof Ihave signed myname to the foregoing specication in the presence of two subscribing witnesses.

- WILLIAM G. ROSS. Vitnesses:

FRANK CALDWELL,

PATTERSON A. REECE.

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