US28910A - Air-engine - Google Patents

Description

0. M. STILLMAN AIR ENGINE.

Patented June 26, 1860.

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UNITED STATES PATENT orricn.

O. M. STILLMAN, OF YS'IOINGTON, CONNECTICUT.

AIR-ENGINE.

Specification of Letters Patent No. 28,910, dated June 26, 1860.

T o all whom it may concern:

Be it known that I, O. H. STILLMAN, of Stonington, in the county of New London and State of Connecticut, have invented certain new and.. useful Improvements in Air-Engines, whereby they are simplified in construction and rendered more efficient; and I do hereby declare that the following `is a full, clear, and exact description of the same, reference being had to the accompanying drawing, which is a vertical section of an engine containing my improvements.

The nature of my invention consists in a means of compressing and working the air in a single cylinder by the use of but one piston. Also in combining the stuflingbox with the induction valve in such a manner that the friction of the former upon the piston rod controls and aids the operation of the latter, preventing it from slamming and aiding it to open and close at the proper periods. Also, in a means of cooling the interior of the piston and piston rod. Also,

in a means of cooling the exterior of the cylinder.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation by the aid of the drawing and of the letters of reference marked thereon.

A is a hollow cylinder with heads A', A.

B is a piston fitted therein having a large hollow piston-rod B cast in the same piece or otherwise attached thereto. At the lower. end of this piston-rod is a cross-head B which is connected by rods C on each side of the cylinder to cranks C on the main shaft one of which cranks only is represented.

N is the fly wheel.

In the -center of the head A I place an annular valve R, extending around the hollow piston rod B, and carrying a stuffing-box R with projecting arms as represented, so that when the valve R is depressed the passage is closed and an air tight chamber is formed below the piston B; but when it is elevated, the passage is open and air is allowed to pass freely. The friction of the stufling-box, R, on the piston-rod, B, tends to move the annular valve, R, in the same direction that the piston B is traveling and to prevent any movement of R at any other time or in any other direction. The arms or stops on R, by striking A prevent the valve R from opening too wide.

An annular chamber, o", around the piston rod B, communicates with the valve R, and also, by pipes r, communicates through the vfloor of the engine room with the external atmosphere. Another annular chamber, L,

exterior to 7", communicates with the interior of the cylinder A through self acting valves H, H, which latter valves open outward from cylinder A. This chamber, L, also communicates through the tube E`with the heater, D, as represented. This heater may be made in a tubular, annular, or other suitable form, and serves thev ordinary purpose of expanding the air delivered thereto by the engine. The top of the heater I) communicates with the top of the cylinder A by means of the pipe F and valve F which valve receives motion from the main shaft, so that itis opened when the piston B is at the highest point and is closed at a proper period during its ascent, to allow the air to act expansively. Other suitable mechanism may be employed in lieu of e and e with the same effect.

M is the exhaust valve fitted in the head A of the cylinder, and is also actuated by ordinary means to open when the piston B is at its lowest point and to close a little before it has reached its highest point.

The operation of my invention is as follows: As the piston B rises by the momentum of the fly wheel, the induction Valve R is raised from its seat by the friction of the stufling box R and cool air flows in through pipes r and chamber r, into the space under the piston B while the air above the piston is blown out at the valve M. IVhen B arrives at the end of its up stroke, the valve F is opened by the cam e, and a measure of compressed and hot air from the heater D is admitted which by its pressure forces down the piston and actuates the engine. As the piston descends the valve R is shut by the motion of the piston-rod and the cold air beneath the piston is compressed until its pressure equals and slightly exceeds the pressure within the heater, when it passes through the valves H, chamber h and pipe E into the heater. The valve F' is set so as to close when the piston has made about one quarter of its stroke, and the remainder is completed by expansion. I prefer to make the piston rod B of such size that the pump side of the piston is about one half the area of the working side, though any other proportion may be employed. If, now, the air in the heater D is doubled in volume by the addition of heat, the pipe, E, will deliver a volume of air one half as great as is used in the working end of the cylinder, but if the air is expanded less the pressure is reduced,

and the pipe E delivers a greater volume, the reverse taking place if the heat is increased.

In the operating of air or gas engines more or less difficulty has always been experienced from the accumulation of heat in the working parts. In order to remove caloric and keep the parts cool, water or air has been caused to circulate in contact with the surfaces of the cylinder'and in some cases water has been introduced to fill the piston. The use of water is objectionable in most cases and impracticable in many, and in the use of air for such purpose no adequate means have hitherto been provided to move the air with rapidity. In my engine I use air for this purpose and have invented the follow ing means of applying it: The piston B and piston rod B are made hollow and a solid plunger, O, is so placed that at each stroke of the piston a portion of the air within it is expelled and made to pass through a narrow annular space between the piston rod and plunger, conveying away a portion of the heat from the metal of the piston and rod. At the up-stroke a fresh quantity of cool air is taken in to the piston through the same opening, to be again expelled; thereby keeping up a constant circulation in close contact with the surfaces which it is desired to keep cool. I also attach a vessel, P, to the piston rod, B, which vessel extends up around the exterior of the cylinder A without touching it, leaving a thin annular space, x, between it and the cylinder. At each stroke of the piston a quantity of air is alternately inducted and expelled through this opening and conveys away the heat which is transmitted downward from the working end, and also that which might accumulate from the compression of air in the pumping end. The pipes r and E pass through openings in the bottom of this vessel which are of sufficient size to allow P to play up and down upon them. By these means I am enabled to keep the working parts of my engine sufficiently cool by the use of air alone and dispense with the use of water, and all the inconveniences accompanying it.

To the several features of my invention herein described, are due the following several advantages: First, by the compressing and working of the air in the single cylinder A, by the use of the single piston B, and the other parts arranged as represented I am enabled to construct my engine more simply, cheaply, and compactly. Second, by the peculiar construction and operation of the induction valve, R, and stufling box, R', I am enabled to open a'large passage for the induction of the air at a very early period in the up stroke of B, and to so control the motion of the valve R by the friction of R', upon the piston rod B', as to close the opening without noise. Third, by the circulation of the air around the plunger O, within the piston rod B, I spread the current over the surfaces and remove the heat from the interior more effeotually and conveniently than has heretofore been practiced. Fourth, by the induction and eduction of the air through the annular space around the cylinder, in the manner here shown, the cylinder is effectually and conveniently cooled and the working parts kept at a proper temperature.

Having now fully described my improved air engine, what I claim as new therein, and desire to secure by Letters Patent is:

l. Compressing and working the air in the single cylinder, A, by the single piston, B, in combination with the valves and air passages R, 7", E, F, F, and M, or their equivalents, arranged and operating substantially in the manner above specied.

2. The combination of the induction valve R with the stufIing-box R, piston rod B, and head A of the cylinder A, so that the friction ofl the stuiing box upon the piston rod, aids and controls the motion of the valve, substantially as herein shown and described.

3. Causing a circulation of air through an annular space between the plunger :O and the interior of the piston or piston rod, for the purpose of cooling the latter, substantially as above set forth. n

4. Cooling the exterior of the cylinder A, by alternately inducting and expelling air through an annular space X substantially in the manner herein described.

O. M. STILLMAN.

Vitnesses:

DAVID SMITH, WILLIAM P. COY.

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