US321739A - Hot-air engine - Google Patents

Description

(No Model.)

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J. J. MQTIGHE.

HOT AIR ENGINE.

Patented Jul 7, 1885..

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7 HOT AIR ENGINE. No. 321,739. Patented July 7, 1885 i I ,f 5 J am mu, muvmu mwmmn c (No Model.) 1 3 Sheetsr-Sheet 3. J. 'J. McTIGHE.

HOT AIR ENGINE.

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UNITED STATES PATENT JAMES J. MCTIGHE, OF FREEPOR'I, PENNSYLVANIA.

HOT-AIR ENGINE.

SPECIFICATION forming part of Letters Patent No.321,739, dated July 7, 1885.

Application filed January 28, 1885.

To aZZ whom it may concern.-

Be it known that 1, JAMES J. MOTIGHE, of Freeport, in the county of Armstrong and State of Pennsylvania, have invented certain new and useful Improvementsin Hot-Air Engines; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification, in which- Figurel is a horizontal sectional view; Fig. 2, a top view. Fig. 3 is a vertical section of heating-tube. Fig. 4 is a vertical side view, partly in section. Fig. 5 is a vertical section of lower part of heating and cooling chamber, showing connecting pipe. Fig. 6 isa vertical sectional View of working-cylinder and pistons. Fig. 7 is a view showing stove or heater and method of connecting flue with both sides of heating-tubes.

This invention has relation to that class of hot-air engines in which the same air, whether previously compressed or not, is used over and over again, and has for its object to provide an engine very compact in size, economical. and reliable in its working, and of such power as to become a substitute, in many cases, where only steam can now be'used.

My invention consists, first, in the nove form of heating and cooling or reversing chambers; secondly, in the novel arrangement of heating and cooling devices within said chambers; thirdly, in the novel form of reversing mechanism contained within said chambers; fourthly, in the novel arrangement of the working'cylinders; fifthly, in the novel means for utilizing superfluous expansive power; sixthly, in the novel means. for preventing heating or cooling of the air at times not needed; seventhly, in all the arrangements and combination of parts hereinafter fully described, and more fully claimed.

In Fig. 1, A represents a hollow cylinder closed at both ends by caps, one of which is removable. This cylinder is divided into two parts or chambers, A A, by the wall B, each portion being made air-tight both as regards communication with the external atmosphere and with each other. The chambers A A (No model.)

are again divided into two portions by the semicircular partitions a a, which are fastened to the walls of the cylinder by screws, and, being slotted, are free to move under the expanding force of the heat to which they will be submitted. The parts between'the parlitions and the sides of the cylinders are fillcd with loose iron plates, forming the regenerators.

The four corners of the chambers formed by the junction of the dividing-wall B and the periphery of the cylinder are partly occupied by tubes 0 O G O, of which a detailed description will be given further on. For the present, suffice it to say that the tubes 0 C in the right-hand corners of Fig. 1 are cool ing-tubes, containing circulating water, and the tubes 0 O in the left-hand corners contain passing flame and constitute the heating devices of the engine. A certain portion of the balance of the chambersis taken up with the reversers D D, which, as appears, are, in a plan view, somewhat of a shield form, and oscillate or rock on their axes. These revels ers always occupy positions as nearly diametrically opposite as possible, the result being that while the air in one chamber is being heated that in the other is being cooled. Obviousl y, as these reversers oscillate they change the air from the hot corner to the cool, and vice versa, in each chamber, respectively.

The object of shaping the reversers as shown in Fig. 1 is that there may be as little useless air-space as possible in the side or corner where the air is not wanted. Near the ends of the semicircular partitions a a are placed gates or clack-valves (Z d, so arranged as to close when the air is following and to open when it is preceding the reverser. The purpose of this is to draw the air around and through the heating or cooling devices when it is desired to heat or cool it, and to furnish it with a shunt passage away from said devices when the aim is to avoid the heating or cooling. The gates or valves (1 d, as shown in the drawings, being clack-valves, are automatic in their working, but may be of such construction as to be actuated, when required, by a posi tive motion from the engine-shaft, the means for so doing being very obvious.

The reversers are of course operated by a positive motion from the shaft, somewhat in a similar manner and in nearly the same relative times as the valves of a steam-engine. To the upper end of the reversers are attached shafts which pass out through and are packed in the top or cover of the cylinder. These twin shafts may be made to turn simultaneously and in any desired periods by many different means. One way is shown in the drawiugsviz., to fasten to each shaft above'the top of the cylinder a small gear-wheel, it, another cog-wheel, k, meshing into and pivoted between them. By turning the central wheel the other two turn in opposite directions, and the reversers within the chambers are compelled to follow and preserve their diametric relations. As shown in Figs. 2 and 6, the central wheel is made to oscillate by the use of levers and a cam on the engine-shaft; but any other suitable means may beadopted. The aim being to cause the reversers to rock to and fro about their respective axes, this purpose -an be obtained in various ways without addinganything to this invention. The reversers are shown in Fig. 1 in section; but it is to be understood that they are also capped and airtight. They may also be divided into compartments, the end toward the cold side of each chamber containing circulating water let in through the shafts and making its exit by the same, as is commonly provided in similar circumstances in ice-making machines.

The two chambers of the reversing-cylinder communicate, respectively, by the open passages E E, Fig. 1, with the two singleaeting working-eylindersthat is, chamber E to the clearance-space above the piston in cylinder F, and chamber E to the clearance space above the piston in cylinder F. These working cylinders containtrunk-pistons ff of any desired pattern, and their connecting-rods actuate the cranks r g of the main shalt G,together with its various attachments, as in any ordinary steanrengine. These twin working cylinders are placed mouth downward for a twofold purpose first, to prevent oil or water getting into the reverser-cylinders,where under the influence of great heat damage might result to the engine; and, secondly, to prevent as far as possible the oil used in lubricating getting behind or rather above the pistons, where, owing to its gradually becoming gummy,it would increase the friction. In steam-engines this oil would be blown out through the exhaust; but as there is no exhaust in this class of hot-air engines means must be adopted to prevent the above inconveniences, and the best way is to place the mouths of the workingcylinder downward. A box or other vessel may be attached to the mouths of these working-cylinders for oil and water for the purpose of better lubrication and to prevent waste of oil. This method of and means for lubricating the working-cylinders is well known, but has never heretofore been applied to a hot-air engine,and in this regard may be considered not merely advantageous,

but really necessary. The two chambers of the reversing cylinder are connected by a pipe, H, Fig. 5. This pipe is closed normally by a plug-valve, which may be opened at any desired moment by a cam on the engine-shaft and immediately reclosed. This valve is pref erably an oscillating one,and its aim is to establish a brief communication between the two reversing chambers,as will appear further 011.

The four tubes 0 C (J C, Fig. 1, above re ferred to, are constructed substantially as shown in Fig. 3. As seen, none of the tubes are quite equal to the internal length of the reversing-eylinder, and each one is divided into two compartments by a wall, c,which goes near to the closed end of the tubes, thus leaving a communicating space, 71, between the compartments. This wall is perforated to es tablish a communication across or through the tube, through which the air in the reverser-cylinders may pass, as before men tioned. In one case the heat or flame goes up one side of the tube from the grate, stove, or burner, and down the other side to the flue. In the other case the water follows a like course from the faucet to the waste. Thus high and low temperatures are maintained, as desired, and entirely within the revel-senchambers,and very extensive heating and cooling surfaces provided.

The heating-tubes may and must be arranged in any convenient manner to allow for expansion, and when cast separately from the cylindcrs may be readily replaced when burned out.

A small air-pump operated by the motion of the engine-shaft communicates with a reservoir provided with two exit-pipes, each communieating with one of the reverser-chambers, and each having a check-valve to prevent the return of air to the reservoir. The rcservoi r itself has an ordinary safety-valve,whie11 may be loaded to any desired pressure. Whatever that pressure be will be theoretically the work ing pressure of the engine, as will appear further on. Thus it will be possible to determine and set the horse-power desired in any degree or fraction within thelimits of bursting pressure of the various parts of the engine.

The operation of the engine is as follows: The reverser-chambers A A and their respective communicating working-cylimlers F F are first charged by hand or otherwise with air at any desired pressure. It may be the atmospheric pressureflifteen pounds, which needs no charging; but suppose they be charged to sixty pounds. The flame and water are let intotheir respective tubes, and let the heatingtubes be heated to about 500 Fahrenheit, the cool-tubes remaining, say, at In this circumstance the heated air acquires a tension of about one hundred and twenty pounds, while the cold air in the other chamber remains at sixty pounds tension. Evidently the piston connecting to the chamber containing heated air will commence to descend undcrthe difference of tension oft hetwo chambersviz.,120

IIO

pressed.

60:60 pounds. At the same time the other piston is being forced upward, compressing the air ahead of it. This compression produces a cer tain amount of heat, which is being rapidly extracted by the water of the tube in its cool-' ing-chamber and into which it is being com- These are-truths long since demonstrated by Stirling and others, and are only referred to in order to explain completely the working of the present invention. The piston under tension or pressure of heated and expanding air, retaining yet the tension practt cally of one hundred and twenty pounds, is about to complete its stroke, the other piston likewise being about on the point of finishing its stroke and consequent compression of cold and cooling air at substantially sixty pounds pressure. At this precise juncture, if the valve between the two reversing-chambers be suddenly opened, as it will be by the revolution of the engine-shaft, the tension between the two chambers becomes at once balanced, one falling from one hundred and twenty pounds to ninety pounds and the other rising to ninety pounds from sixty pounds. Here is a dead point. The movement of the fly-wheel carries itself beyond the dead-point. The valve above referred to is closed by a positive motion. By a positive motion, also, the reversers are immediately changed and the shaft receives a new impulse from the tension of the air heating in the second chamber and cooling in'the first. Thus the operation proceeds. In the meantime the pump is being also operated, the reservoir safety-valvebeing loaded, say, to sixty pounds. If at any time the air in either reversing-chamber, owing to leakage, becomes less than sixty pounds, sufficient air will pass to it from the reservoir to restore it to -its normal pressure when cold.

Thus the engine will work at any pressure which the material of which it is constructed will withstand. Its working pressure will be theoretically the difference of pressure between the two reservoir-chambersin practice lessor, in other words, its theoretical working pressure will be the load carried on the safety-valve of the reservoir.

- Having described myinvontion, I claim 1. A reverser-chamber for hot-air engines, divided into compartments, each compartment having a vibrating reverser, substantially as shown and described.

2. A reverserchamber for hot-air engines, divided into compartments, each compartment having a vibrating reverser therein, and a workingcylinder communicating therewith, substantially as described.

3. A reversing device for hot-air engines, consisting of chambers, and a means, substan tially as shown and described, for establishing communication between said chambers, whereby the superfluous pressure at the end of the stroke of the piston is transferred from one chamber to the other.

4. In a hot-air engine, the combination of a vibrating or rocking reverser and a heating or cooling device contained within the same chamber, substantially as described.

5. In a hotair engine, the combination of a heater and cooler and a vibrating or rocking reverser contained within said chamber, substantially as described.

6. In a hot-air engine, the combination of chamber A, inclosing heating or cooling tubes 0 O, with vibrating reverser D, whereby the air is transferred from one side of the chamber to the other, substantially as described.

7. In a reverser for hot-air engines, the combination of heating and cooling devices with shunt or auxiliary passages connecting the ends of said reversing-chambers, substantially as described, whereby the air may be trans ferred from one end to the other without com ing in contact with the heating or cooling devices.

In testimony that I claim the foregoing as my own I have hereto affixed my signature in presence of two witnesses.

JAMES J BIOTIGHE.

WVitnesscs:

A- A. Moonn, THOS. A. CoNNoLLY.

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