USRE676E - Improvement in steam-gages - Google Patents

Description

T.' STUBBLEFIELD.

4 Pressure Gage.

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THOMAS STUBBLEFIELD, OF GOLMBUS, GEORGIA.

IMPROVEMENT lN STEAM-GAGES.

Specification forming part ol' Letters Patent No. 11,333, dated July 1B, 1854 Reissue l`No` 676, dated March iii, 1659.

To all whom it may concern Be it known that I, TnoMns SrunnLn- FIELD, of Columbus, in the county of Muscogce, State of Georgia, have invented certain new and useful improvements in devices for measuring the pressure of fluids and also for closing the aperture for their admission or discharge, of which the following is a full, clear, and exact description, reference bein-g had to the accompanying drawings, forming part of this specid'cation, which represent these devices as applied to measure the pressure of tluids.

Figure 1 represents a sideielevation of a steam-gage embracing my improvements and applied to a steam-boiler. Fig. 2 represents a transverse section ou the line .r ar of Fig. 1,

and Fig. 3 represents o transverse section on the line l 1 of Fig. 1.

The apparatus consists of a cylindrical casing, A, closed at both ends by screw-glands B and C, with an exterior tubular nozzle, c and `g, to each gland, Aby which a'communication is made from either end with the interior of the easing. NVithin this casing is a spring-valve consisting of a rod or stem, b, the lower end which is screwcdinto a stud, f', on the center of a disk, D, which forms the base of the valve, and rests on a seat, d, formed by an annular projection, l, on the inner face ,of the lower gland, (l. A rim, c, around the edge and on the upper face 'oi' the disk D, forms a. cup to receive the lower end of a hollow cylindrical vulcanized-rubber spring, E, the upper end of which is received into a corresponding cup formed by an annular projection, c, on the interior face vof the upper glanjd, The external diameter of the rubber springis somewhat greater than the interior diameter of the anges surrounding either end, that it may lit closely therein. 0n the interior oi' the rubber Kspringis a spiral wire" spring, I, surrounding the stem without touching it, which for thisy purpose L prefer to make of hardened brass. The valve-rod b passes through and extends beyon the end-oi' the upper tubular nozzle, a,i which it loosely lits, and on the outer end of this rod is set a nut, h, which, on being screwed down, bears on the end of the nozzle a, holds the disk and gland B in close contact with the ends of the rubber spring, so as-to form a tight :sprin passage of either water or steam from below through the upper gland, while the external air has free communication with the interior of the valve.

To the valve-rod b may be attached a circular graduated indicator-plate, and connection made between the rod b and index-hand o by means of a link, q, pivoted at one end to the rod b and at the other end to a toothed sector, o, which gears into a pinion, P, on the axis of the index-hand.

This apiiaratus, when used as a steamgage, is connected with a steam-boiler in the manner shown in the drawings, by means of a screw-coupling, H, which connects the nozzle g of the lower gland with a Siphon-pipe, P, whose opposite end communicates with the interior of a steam-boiler, S, so that-the steam will have free communication with thc space m below the valve. The pressure ot the steam in the boiler is transmitted through the pipe P, acts on the under side of the valve, raises it from its seat, compresses the springs until their resista-nce corresponds with the pressure `otthe steam in the boiler, and as the pressure of the steam in the boiler varies, increasing or diminishing, so also does the position of the valve change, and the valve-rod is protruded a greater or less distance beyond the end of the nozzle a. The motions of this rod through the connections previously described give motion to the index-hand, causing it to traverse the indicator-plate, which is graduated to correspond with Vthe movement of the valve due to the varying pressure of the steam in the boiler to the square inch, and these grail nations give that pressure in pounds. The spiral springs within the tubular rubber spring not only give to it greater power and strength, but prevent it from collapsing by the pressure of the steam en its outer surface, which, were it to do so, would bind the-rod b, increase its friction, and thus prevent the gage from giving a true indication ofthe pressure of the steam in the boiler. If, howeverthe pressnreto be indicated should be so ow or the thickness of the rubber tube so great that there would be no liability of its collapsing, the wire sprn g may be omitted. To prevent the rubber when applied to steam-gages from being a ected by heat so as to change its elasticity, the connection between theV gage and the steam-boiler may be made by a long,

small, inverted, siphon-pipe, and the gage placed in such position as to be several inches below the point at which the pipe enters the boileigand it would in all cases be best if the lower bend of the pipe was below the bottom of the boiler, although its connection should be with the steam-space aft the top.

From the arrangement of' these devices, as described, it will be seen that the valve is pressed toward the seat by the action ot the rubber spring; that the rubber spring also performs the oliee of a )nanometer-spring when pressure is applied to the face of the valve; that it packs the valve-stem without binding it, and that it alsocuts off communicatin between the apertures in the opposite ends ofthe ease Without packing or binding on the sides of the case.

What I claim therein as new,a.nd desire to secure by Letters Patent, is-

1. Thccombi'nation of' a case perforated at both ends withinJ spring-valve., the spring forming the sides of the valve beingA arranged so as to eut olfeommnnication between the perforations in the opposite ends of the case, and perform the duty oi a manon]eter-spring, as described.

2. The combinations of valve, stem, disk, and gland with the interposed rubber spring, arranged substantially as described, so as to press the valve toward its seat and pacl the valve-stem without the spring binding;l the valve-stem or the valve ease.

In testimony whereof' I havesnbscribed my name.

THOS. STUBBLEFI-ELD.

Witnesses:

F. Scauri-rene Smm, JOHNS HoLLrNesnEAn.

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