On the spring safety valves of the boilers of locomotive engines

JOURN

AL

OF q[' }~ 1.:

FRANKLIN

I NSTITUTE O F T I t 1~5

DFVOTED

q'O

THF.

MEOHhI~I~ 2~RTS~ M A I ~ U P A U T U R E S , A N D '1'1-t1'; R I ~ ; C 0 ] ~ t ) I N ¢ ~

A:~IERICAN AND O T I t E R JUNE~

G~NERAL

SCIEI~GE,

OF

PA'I'ENTI~D

INVENTIO:NS.

1 S3:~:.

On the Spring Safety Valves of the _[?oilers oj" Loeomotive Engines. TO Tl:I:g COX)I:ITTEE 031" r U l l L 1 C A T I 0 ~ S . GENTL EMEN~

Observing that the improved sprin~ balances are being brought into general use, for loading tile safety valves ot the boilers of loeomotiv8 engines, I will take the liberty of p o i n t i n g out some of their defects, when applied to that purpose. In the first place, the apparatus permits the valve to be loaded to an unlimited degree, by screwing the lint until the index is drawn out to its |'all extent, the common melhod of attaching them to the lever b e i n g by means o f a s c r e w and adjusting nut. The facility with which the valve can be overloaded will prove, in the hands of careless or ignorant persons, a source of great danger. Secondly, when the s t e a m is high enough to blow off, the load increases with the pressure of t h e steam; this was proved by an experiment with a safety valve, tile l e v e r of which was so proportioned that one pound at its end, gave ten pounds pressure on the valve. When the valve was closed, t h e index of the balance stood at l~ lbs., (tlm index moves through a s p a c e of about one-eighth of an inch for each pound,) and when the s t e a m began to blow off, the index pointed to fi~urteen pounds; showing that there was an additional pressure of nearly £0 lbs. on the v a l v e . It is well known that the use of the simple weight was laid a s i d e on account of the tendenVoL. XI ~ N o , 6.~JrJN:~ 18~3.:3. 46

362

Note oTt the Properties of ,~ilicon.

cy to batter the valve, and to permit the escape of steam, from the tremor of the carriage. I purpusenow to suggest a plan which I think will not have the disadvant.t~es j u s t spoke ~ of as belonging to the common weight, nor those belove alluded to as affecting the spring weighing machine. It is illustrated by the fbliowing figures.

:B

H

In fig. 1 is shown part of the usual lever, with an improved weight; the apparatus is shown more completely by fig. ~, which is a evnss section of fig. 1~ in which A is the lever upon which rests a weight suspended by a spring. Fig. 3 shows a cylinder, B, or case, to contain a spring and stem, the latter having a hole in its top through which the stem works. C is the weight which is secured to the fork on the lower end of the case. In fig. 4 the stem and saddle is shown in detail, and E is a spiral spri,lg of steel; this is made to wot'k freely between the inside of the case and stem, the.u ~pe' end being [astened to the top of the cas% and the lower to the pm on the stem. Yours~ respectfully, A. c . a.

Note on the Properties of ,~ilicon. By Ro~a~l~l:IIaaE, M. D. Professor of Ghcmistry in the University oF Pennsyh, ania. T0

Tile

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GEXTL~tEN~--Since [ enclosed to you my paper on the evolutiort of silicon, I have made the following observations. The silicou left