US73456A - Improvement in steam-engine pistons - Google Patents

Description

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ALEXANDER NADOW, OF SPRINGFIELD, MASSACHUSETTS.

I Letters Patent No. 73,456, dated January 21, 1868.

IMPROVEMENT m STEAM-ENGINE PISTONS.

TO ALL WHOM IT MAY CONCERN:

Be it known that 'I, ALEXANDER Nnnow, of Springfield, Hampden county, Commonwealth of Massachusetts, have invented certain Improvements in the Pistons of Steam-Engines; and I do hereby declare that the following is afull and exact description thereof, reference being bad to the accompanying drawings, and to the letters of reference marked thereon. In the drawings Figure 1 is longitudinal section of a steam-cylinder, A, .showing the piston B, as arranged in my invention. A J

Figure 2 is a eross-scction of the same, showing the piston B, with one head, 0, removed.

Figure 3 is a section of the pistonQwiththc ring Z) removed; and

Figure 4, avicw of the piston, with the ring 6 removed.

The object'ot' my invention is to obtain a cheap and accurately-fitting piston, which is packed or rendcred steam tight, by means of a ring, Z1, formed in two or more segments, and expanded against the inside of the cylinder by means of steam, which is let inside of the piston in a peculiar manner, or, if preferred, by means of a spring inside ofthe piston, the form of the ring and manner of letting the steam inside of the piston-being the improvements constituting this invention.

The construction is as follows: The outside ring I) of the piston Bis formed of two or more segmcnts,- C G, fig. 2,and fits over the piston, as shown in fig. 3, having two heads, a c. This ring, at the joints m m, is of peculiar form, as shown in 1, so as to allow it to spread out against the cylinder, for if the space d be made very much larger by the expansion of the ring, no steam can get by, as it is stopped by the part 8 of the joint, when the two parts of the ring are ground to an accurate fit.

Pistons, a s usually constructed, are made of.a number of rings, placed sidc'by side, and cut at only oneplace in each ring, and placed on the piston so as to break joints, or else are made of a great number of segments, also brcakingjoints. New, in the first case, any expansion of the rings throws them greatly out of the form of a true circle, thus making an inaccurate fit in the cylinder, and in the second case, they are very expensive. New, in my invention, only one ring is used, with joints, as described, made in two, or at most, three segments, though I do not. wish to confine myself to any particular number, and thus forms a very cheap and durable; ring, and also, when expanded, it fits the cylinder much better than a ring out in only one place.

I Inside ofthis packing-ring is a double ring, of thin metal, ff, which serves for the steam to act against when let inside of the piston, as I will now describe. 9 is a valve hung on a pivot, at 11. Under each end, of this valve is aport, 7a is, communicating with the cylinder at each side of the piston. Now as steam is let on at one side er the piston it enters at this port, it, and blows up into the inside of the-piston, and as it does this, the valve 9 isimoved so as to cover the port it, and thus preventing the steam from blowing through the piston. As the steam comes inside of the piston, it acts onff, the thin metal ring spoken of, and forces it out against .the packing-ring 6, which isforccd against the inside of the cylinder, thus packing the piston.

One objection to self or steam-packing pistons has been that they required so much room for expansion, that when used without steam, as in the case of a. locomotive going down a grade, all the ports being loose, would lie on the bottom of the. cylinder, and thus wear it out of a circular form, but in this arrangement, so little room is required that a very small amount of space between the packing-ring and the cylinder is necessary, thus obviating this difficulty. The simplicity of this arrangement makes it nearly impossible to be got out of order, while the two great requirements, eheapncss and durability, are at the same time combined with this simplicity.

New, having described my invention, what I claim as new, and desire to secure by Letters Patent, is-- The valve y, when used in combination with the piston 13 and ports 7c is, substantially-as described.

ALEXANDER NADOW.

Witnesses:

J. 'B'. 'GARDINER, MILTON BRADLEY.

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