US140223A - Improvement in fastenings for safety-valve cases - Google Patents

Description

Patented June 24,1873.

(fimusem I ff. M. I

UNITED STATES GEORGE B. SISSON, OF BUFFALO, NEW YORK.

IMPROVEMENT IN FA'STENINGSFOR SAFETY-VALVE CASES.

Specification forming part of Letters Patent No. 140,223, dated J une 24, 1873 application filed February 27, 1873.

In the drawings, Figure 1 is a sectional side elevation. Fig. 2 is a sectional front elevationi Fig. 3 is a plan; Figs. 4 and 5, detail views of the hasp. v

A is the base or steam-chamber, whose bottom, a, is made with an inner screw-thread, by which means-it is secured to the boiler. In the top is the valve-seat b. The interior of chamber A is provided with across-piece, 0, into the center of which the spindle or guide-rod dot a valve, B, sets, as shown. on

top of the valve B is another spindle or stem,

c, which passes upward through a crosshead or plate, 0, which is secured by'suitable nuts f, g to two upright posts,D D (See Fig. 2.) Surrounding the stem e, between the crosshead c and valve B, is the usual coiled spring 'E, the whole thus forming the usual spring safety-valve. To make it a lock-valve, I provide a cover or box,

F,-which sets over the spring and valve, with its. lower edge resting upon the top flange h of the chamber A, as shown, and with au'opening, G, in the top'for the escape ofthe steam, i is a slot or opening through one side of the flange h, (see Fig. 1,) through which-a gib-hook, 7', passes, which is riveted. tothe side of the box F, the hook-part catching on the outside of the edge of the flange h, and thus holding that side of the case F down. The opposite side of the flange is also provided with a slanting slot, m, through which a tongue or lever-hasp, n, is passed frombeneath, having a slot, '1), in its upper part fitting over a staple, r, secured to the side of they case F, as shown, by which means other important feature of novelty in my invention, as vby this means I fasten the case F by only one look, and doing away with hinges, which allows 'the outer case to be removed entirely from place, to readily reach the valve, &c., for repairs or tests.

In all lock-valves with which 1 am acquainted there is no means of ascertaining whether the valve is in goodorder or not without unlocking them, or raising the pressore of steam .in the boiler unless it has reached the point at which the valve is set. The latter is inconvenient, and sometimes dangerous, while the first is only practicable when the inspector is present to unlock it. It is usual to attach to boilers an extra safety-valve for use, in cases of emergency, but this does not obviate the main di-fliculty, which is to ascertain whether the lock-valve is in good order or not.

To accomplish this, I provide. a shaft, H,

which runs across through the top part of the case F, as shown, and which is provided with square ends, 8 s, by which means it may be turned from the outside to raise the valve. On the center of this shaft is a forked catch or wiper, I, which catches either side of the top of the valve-stem 0, above the crosshead (J, the top of. said stem being provided'with a head, it. By this means the valve may be operated from the outside of the cover, but, at the same time, will not allow it to be held down, or otherwise tampered with. I thus entirely obviate the greatest objection to lock-valves, as well as do away with the necessity of an extra'valve,-

as by the use of the shaft or rodH it may be used as a common safety-valve without interfering with the lockingpart of it. W is the usual platesuspended over the orifice G to prevent the valve being reached from In witness whereof I have hereunto signed above. my name in the presence of two subscribing I claimwitnesses. The gib-hookj, and locking-hasp n, in com- GEORGE B. SISSON. bination with the case F, and chamber A Witnesses: having the slotted flange h, substantially as J. R. DRAKE,

described, for the purpose specified. O. N. 'WOODWARD.

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