US54716A - Improved safety-valve for steam-generators - Google Patents

Description

e, Unimet) STATES KParitair GFFICE.

VIRGIL D. GREEN, OF WATERTOWN, WISCONSIN.

IMPROVED SAFETY-VALVE `FOR STEAM-GENERATQRS.

Speeication forming part of Letters Patent No. 54,716, dated May 15, 1866.

To all whom it may concern.-

Be it known that I, VIRGIL D. GREEN, of

lWatertown, in the county of Jefferson and State of Wisconsin, have invented a new and Improved Arrangement of Safety-Valves for Steam-]3oilers; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to make and use the same, reference being hadto the accompanyingdrawings, forming a part of this specication. n

The object of the present invention is to enable a large safety-valve to be used for the escape of steam from a boiler, while at the same time the use of a long lever or heavy weights or rigid and stiff springs are dispensed with; and it consists in arranging upon the boiler, in a suitable aperture thereof, a hollow cupfsliaped valve opening outward and having an inside diameter greater than the diameter of the said aperture, which valve, by its open end, plays steam-tight upon a xed center-plug or piston, having through its center a passage formed leading to and opening into the boiler, for the steam to pass from the boiler intothe said valve, in the end of which steam-passage, commun icating with the boiler, is arranged a val ve opening inward, and so connected through a suitable stem with another valve of said steam passage, but opening outward, that when one is open the other is closed,the latter valve being held down by means of a weight, spring, or any other suitable device properly adjusted to the degree of pressure which it is desired the steam in the boiler should not exceed. By this arrangement it is obvious that so long as the pressure of steam within the boiler does not exceed the downward pressure upon the weighted valve the passage of steam from the boiler to the interior ofthe cup-shaped valve is free and uninterrupted, consequently producing sufficient pressure upon the inside of such valve, as its surface there exposed to the pressure of the steam is greater than its end fitting in the aperture ofthe boiler and subject to the direct action of the steam therein to firmly hold it to its seat in the boiler, the valve at the boiler end of the steam-passage leading to the hollow-valve being then open, and consequently the weighted valve closed. In this relative position the several valves remain until the pressure of the steam in the boiler has sufficiently increased above that of the weighted valve to raise or open it, consequently at the same time closing the valve in `the steam-passage from the boiler to the cup- Lshaped valve, and thus stopping the passage iof steam through it, through which weighted `valve the steam in such passage, as well as in the cup-shaped valve, then escapes to the open air, thereby relieving the inside pressure upon such valve, by which it is held to its seat, when the steam-pressure within the boiler, immediately raising such valve from its seat, opensit `to the escape of the steam from the boiler, `which continues so long as the boiler-pressure fis above the pressure of the weighted valve,or fsuftieiently so to hold it open,butis immediately ,stopped the instant the pressure is reduced bejlow such amount by the falling or closing of the weighted valve, and consequent opening ot' 1the boiler-valve in the steam-passage tothe rcupfshaped valve, whereby the steam-pressure ,again acts upon the inside of the cupshaped valve, bringing or forcing it to its seat, where `it remains until the boiler-pressure again exceeds the amount of pressure on the weigh ted valve, Awhen the same relative movements ot' the several valves again take place as above explained, and so ou at each and every increase of boilerpressure- In accompanying plate of drawings myimprovements are illustrated, Figure 1 being a plan or top view, Fig. 2 a side elevation, and Fig. 3 a central vertical section taken in the plane of the line a' a', Fig. l. K

Similar letters of reference indicate like parts.

A in the drawings represents, for instance, the top plate of a steam-boiler, which may be made of any of the ordinary constructions of such boilers, in which boiler-plate an aperture or opening, 15 is formed with its edge ared or beveled outward. In the dared portion Vof this opening B tits the beveled or flared lower end, C, of a hollow cup-shaped valve, D, playing steam-tight by its open and upper end, E, over a fixed piston or plunger, F, secured to the under side of the top plate, G, of the chamber or box H surrounding the said valve D. Through the. center of this fixed piston or plunger F extends a passage, I, leading therefrom to the top of the boiler, with the interior of which it communicates through a flared aperture or opening, J, having avalve, K, arranged in it opening inward. This valve K is secured to the lower end of a vertical rod or stem, L, extending upward through the censteam in the boiler, the weighting of this Valve N being the same as in ordinary safety- 4 valves.

From the above description of the arrangement ofthe two valves K and N, attached to a common stem,L, itis obvious that when one is open the other will be closed, and vice versa, the steam, when the valve K is open, passing through the steam-passage I leading from the boiler directlyinto the hollow cup-sh aped valve D, the internal diameter oi' which is intended to be sufficiently in. excess ot' the boiler-aperture, in which it lits or comes to a seat, that the inside pressure of steam will more than balance the direct pressure of the steam within the boiler upon its lower end, and thus firmly hold it down and to its seat, where it remains until the steam-pressure in the boiler exceeds the amount to which the valve N is weighted, which it consequently then Yraises and opens, at the same time closing the valve K, stopping the passage of steam through steam-passage l, from which, as well as the interior of the cup-valve D, the steam then escapes through said open valve N, relieving' the inside pressure upon the valve D, which then, by the action of the boiler-pressure upon the lower end, immediately rises and opens, giving a rent to-the steam from the boiler through its aperture B intothe chamber H, from which it escapes to the open air at R, said valve D, as soon as the boiler-pressure has thus become reduced to the desired amount, falling and closing, while at the same time the weighted valve N closes, (the valve K ofcourse opening,)

and the steam communication is again established with the interior of the cup-valve D, which so remains until theboiler-pressure again exceeds the amountto which the weightedvalve N is adjusted or set. By this arrangement of the valves K, N, and D so as to operate with regard to each other, as explained, it is manifest that a small weighted valve may be used, while at the same time a large vent is obtained for the steam to escape from the boiler in case it should exceed the amount of pressure desired, the importance of which arrangement is apparent to all conversant with steam-boilers.

In order to assist the closing ofthe cup-Valve D, I use upon its inside a light coiled or spiral spring, S, resting at one end upon the valve D and at its other hearing against the lower end of the xed plunger F, around which the' valve iits steam-tight.

T is a steam-passage around Valvechamber H and upon the opposite side to steam-passage I, for the equalizing ot' the expansion oi the said chamber-plate.

a is a small opening through bottom of cupshaped valve to allow condensed steam in it to escape.

I claim as new and desire to secure by Letters Patent- The combination of the cup-shaped or hollow valve D, steam-passage I, and weighted Valve N, and boiler-ValVeK, connected to a common stem, L, when arranged so as to operate together substantially as herein described, and for the purpose specified.

VIRGIL D. GREEN.

Witnesses CHARLEs M. DUoAssr, LEONARD PAoHoLING.

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