USRE3802E - Improvement in balance slide-valves - Google Patents

Description

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UNITED STATES PATENT GEEICE.

WILLIAM M. STEVENSON, 0F NEWCASTLE, PENNSYLVANIA.

IMPROVEMENT IN BALANCE SLIDE-VALVES.

Specification forming part of Letters Patent No. 83,336, dated October 20, 1868 Reissue No. 3,802, dated January 18, 1870.

To all whom tt may concern:

Be it known that I, WILLIAM M. STEVEN- SON, late of Sharon, in the county of Mercer and State of Pennsylvania, but now of Newcastle of the said State, have invented a new and useful Improvement Vin Balance Slide- Valves for Engines; and I do hereby declare the same to be fully described in the following specification and represented in the accompanying drawings, of which- Figure 1 is avertical section of a. steamchest and the valve thereof as provided with my invention. Fig. 2 is a transverse section of the same. Fig. 3 is a top view, and Fig. 4 a bottom view, of the valve.

Thenature ot' my invention consists in a balanced valve provided with grooves on its upper edge, and having its chamber open both at top and bottom, and a pair of triangular prisms arranged in each groove, and over one or more holes made through the bottom of the grooves, so'as to open communication with the groove and the steam-chest, the wholev being in manner and so as to operate vas hereinafter described.

1n order to enable others skilled in the art to construct and use my invention, I will now proceed to describe it and its mode of operation.

The steam-chest is shown at A as provided with a valve, B. The end and side walls ot' the said valve are shown at a a, they being properly formed to operate with the inductionports b b ot' the cylinder C, the eduction pas- Between the said walls is a cavity or chamber, d,which is open both at top and bottom, such chamber being formed in manner as represented. Each of the walls of the valve at its top or upper 4 part is furnished with a groove or chamber, K, to receive two packing-stripsor right-angled triangular prisms, e e, which are arranged in the groove in manner as represented in Fig. 1. 4

| One or more holes, t', lead out of the lower part of each groove in manner as shown in Figs. l and 2, the purpose of such holes being to admit steam from the chest to pass into the groove and' underneath the lower of the two prisms or packings andforce it upward against the upper one, so as to crowd it both laterally and vertically. The packing-strips, by their forms and by the pressure of the steam, will be forced upward against the cap of the chest and laterally against the sides of the groove, so as to make tight joints against their bearing-surfaces. The valvewill be seated or forced downward at the same time, and thus both at top and bottom it will be caused to work with close joints. The cavity d between the walls ct a will be filled with exhaust-steam from the cylinder when steam may be flowing from the chest into eitherinduction-port. Theexhaust-steam will cause a downward pressure on the port-laps, such as will nearly, if not entirely, counterbalalice the pressure tending to elevate the valve oft' its seat at the most critical points of the travel ot' the valve.

What I claim as my invention is The improved balanced valve, substantially' as described-viz., as constructed not only with a chamber open at top and bottom and with grooves having openings through their bottoms and arranged at the upper part of the valve, as set forth, butwith a pair of triangular prismatic packing-strips arranged in each of such grooves, whereby such strips, when forced upward by the steam against the top of the steam-chest to make therewith aclose joint, will be caused by their' action against each other to be moved laterally against opposite sides of their groove, so as to make close joints i with such sides, the whole being as specilied.

WM. M. STEVENSON.

Witnesses:

R. H. EDDY, L. N. MoLLER.

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