USRE3313E - Improvement in hot-air engines - Google Patents

Description

3 Sheets-Sheet.` 1.

P. SHAW. HOT AIR ENGINE.

Reissued Feb. 23, 186'9.

3 Sheets-Sheet 2,

P. SHAW. HOTAIR ENGINE.

Reissued Peb. 23, 1869.'

w: Cams PETERS ce, Pmmmm., Mmmm. D. c.

3 sheeuhsheet 3.

P. SHAW.

HOT AIR ENGINE.

No. 3,313. Reissued Peb. 23, 1869.

ma mums PETERS co. PHoroM-mo.. wAsHmaroN, o. c.

emasafe .SHAWS .UNION AIR-ENGlNE COMPANY,`

SHISIEH' ASSIGNEES OF l PHILANDER SHAW.

Letters Patent. No. 33,799, dated November 26,-1861; reissue No. 3,313, dated Februa/ry 23, 1869.

IMPROVEIENT IN HQT-AIR NGINS.

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To all mnnl/ pomern Be it knownl that I, PHILANDER SHAW, of Boston, in the countypf Suffolk, aud State of Massachusetts,`

have invented certain new and useful Improvements in Hot-Air, or Calorie Engines; and Ido hereby deelare that the following, taken in connection with the drawings which accompany and form part of this specii ication, is a description of myinvention, so full and excentrally located, or nearly so, between the said cyl# inders, and-within an air-tight casing, which forms a .reservoir for compressed and heated air, and is so divided, by partitions and diaphragme, as to receive the cool-supply air at or near the exterior of the reservoir, and to guide it inward, by a tortuous passage, to the furnace, in substantially the manner described, so that it shall absorb the heat radiated fromsuch parts of the engine as receive the products of combustion, those parts of the engine cylinders, in which the pistons fill the bore, being located outside of and upon the casing as a foundation, and exposed to the atmosphere, and the other parts of the cylinders being located within the casing, so that the heat radiated therefrom shall be absorbed by the cool-supply air on its route to the furnace. l v

Second, in a peculiar construction 4and arrangement, substantially such as herein is described, and is illustrated in the drawings, of the hot-air cylinder, the packed part of its piston, and a piston-trunk, which, with. the necessary packing-valvesiand other adjuncts, form a pump by which cold air is compressed Yand snpplied to the furnace, to be expanded by heat. The pump, being annular, is exposed, inside as well as'outside, to the cooling-iniluence of the atmosphere, and, when compressing the supply-air, being operated by the vdirect pressure of the expanded heated air on the engine-piston, the strain necessary to compress the supply-air is applied directly, andis not transmitted through the rotative parts of the mechanism. this annular arrangement of the pump, I am enabled to reduce the height which would otherwise be needed by my engine, by connecting the pitman direct to the engine-piston. 'l-he pitman thus vibrates within the trunk, and good facilities are had for keeping cool the joint of the pitman with 'the piston, and for lubricat formed around the interior of the cylinder, at the part thereof where the lower edge of the closely-fitting portion of the piston comes at the lowest point in its downward stroke. This chamberreceives a supply of pure, cool., compressed air, by means `hereinafter described, for the p urpose of keeping the piston-packing cool, and that part of the interior surface of the cylinder against, which thepiston slides, and to keep solid products of combustion from rising tothe upper part of the cylinder with each incoming supply from the furnace. Thisrchamber or groove also serves to receive the lubricating-fluid, which escapes, past the packed portion of the piston, and as much moreas may be introduced therein by means of oil-pumps, 85e. Into the duid contained in this groove, the lower edge of the piston may be made to dip, and so lubricate 'the inner surface of thev cylinder at each stroke of the piston. The groove or chamber may be made toreceive an isolated circular trough to receive th'e oil, as shown ,in iig. (i-which, by means of the introduction of cool, compressed, and pure air-around it, prevents evaporation of the oil by conducted'heat, which might occur-without the use 'of the isolated trough.

Fourth, in the construction of an inwardly-projecting dange, as shown and described, which flange may form part ofthe boundary of the circular chamberI `before referred to, and which comes nearly, but not quite into contact withithe contracted and extended part of the piston, for the purpose of deflecting such solid matter from the furnace, as may ,find entrance into the cylinder along with the gaseous products of combustion, and preventing the same from abrading the iinished surfaces of the piston-andfcylinde,

Fifth, in the arrangement of an auxiliary valve, op' erating to admit, from the reservoir,'in which the air is maintained under pressure, comparatively cool and compressed air into the circular vgroove around the, cylinder, and into the clearance-spaces within and con` neeted with the cylinder, for the double purpose of balancing the pressure upon the maininlet-valve into the cylinder, and to maintain the vfinished surfaces'of the piston and cylinder, where one moves upon the other, at a temperature which will not prevent lubrication.

Sixth, in regulating the speed of hot-air engines,

placing a valve, which is operated by the regulator ,of the engine, so that it shall obstruct the passage of air on its way from the air-pump to the working-cylinder, and thus cause an additional resistance to the motion of the air-pump piston, said resistance continuing to act against the motion of the piston until the velocity of the engine is reduced to its normal rate. By the common method, that is, by regulating the speed of the engine by the exhaust-regulator, or, in other words, by diminishing or increasing the pressure, the

ypower of the engine is 'reduced to the work actually Abeing done, although the work may be but a tenth.

f part of that which the engine is capable of doing. If,

now, while the engine is thus working, thek amount'of work is suddenly thrown'l upon it, which will, perhaps, require most of its normal power, the effect will be to so check its velocity that it cannot recover its pressure, and' thus stop it altogether. By my method, any increase in the speed of the engine will cause the regulating-valve to obstruct the passage of air from the pump tothe cylinder, and give an additional resistance ro the action of the pump, which serves to check the engine, while, at the same time, the pressure is kept `at its normal point, thus leaving the engine always ready to act up to its normal capacity. It will be seen, that by m5' method, the engine may be even stopped for a moment, by the regulator-valve, and yet the pressure in the cylinders remains at-its normal point, so that the engine is ready to start without having to wait to re-establish a workingfpr'essure. The ordinary method of regulating the speed of an air-engine, by allowing the escape of the condensed air, and thus reducing the pressure, is objectional, on account of the loss of time which is consumed while the engine is. working up to the required pressure, The common method will not checkthe speed of the engine, 'when work isthrown off, as quickly as mine will,

, for thereason that it simply reduces the pressure on the piston, while, by my method, I reduce the pressure on the piston, at the same time increasing that on the pump, thusacting in two ways to check the speed of the engine'. Again, when work' is thrown on, an engine, with my r'egulaton' has already the necessary pressure, and it recovers its speed at once, but any engine with the common regulator, must have time to make up' the 4pressurenecessary to the work,`

Seventh, in the construction and combination Iof the devices for cooling all the essential parts of the engine,A

by causing' a circulation of the cool air from the air pumps through and around the different parts of the engine.

The importance of this cooling-arrangement cannot be overstated, as, in fact, the whole practical value of an air-engine may be estimated, other things being equal, upon the relation between the temperature of its working-parts and thepressure generated; in other. words, no air-engine can work steadily and economically, unless the working-parts are kept comparatively cool.

In my engine, the parts are arranged with this end in View, as will be seen, if We follow the course of the air from the air-pump to the furnace. Thus the air is A taken into the air-pump through' the valve n, Figure 2;

thence sent through the pipe K L, Figure l, into the chamber formed by the plates E and j around the central part of the cylinder, and near the oil-receptacle, c, thus keeping this most important part of the cylin- --der cool; thence, the air passes through an opcning,j,

-. Figure 3.

The cool air from' the pump having thus traversed through and about all these parts, cooling `on its passage the central and lower part of the cylinder, the valves and stems, and the casiugs, and in general all of the important parts ofthe engine, pass finally through vthe pelforations in the plates t and b, iig. 1, into the furnace.

` Drawings. Sheet No. l illustrates in half-side elevation, and in half sectional elevation, arhohair, or caloricengiue em bodying my invention, the section being taken 'in the lines y y, SheetNo. 2, 'z z, lSheet No. 3.

Sheet No. 2 is an end elevation of the same, a pa however, being shown in section taken in the lines yl y', Sheet No. 1, and :d a', Sheet No. 3, for the purpose of showing the fuel feed-box.

Figure 3, Sheet No. 3, illustrates the same in half plan and in half horizontal section, taken in the lines z z, Sheet No. 1, and z2 z2, Sheet No. 2.

Figure 5 is a sectional elevation, taken in the line y y2, iig. 3,4)f so much of the cylinder, and the parts connected therewith, as toillustrate how the exhaust escapes into the radiator or heater.

Figure 6, an enlarged section, shows the groove or chamber in the cylinder, the isolated trough therein,

and the inwardly-projecting ange.

E is the casing, which, as it forms the reservoir for the compressed air, and the foundation or bed-plate for Vthe mechanism, should be so made as to be air-tight under the heat, strains, and pressure to which it is subjected, and wherever moving parts pass through it, they should be carefully packed.

Centrally located in E is the furnace, lined with irebrick, J, figs. l and 3, and provided with grates, c, figs. 1 and 3, and an ash-pit, which has an air-tight door, I, figs. 2 and 3,.and fuel-receptacle H, figs. l, 2, and 3, from which fuel is fed to the fire through the top of the furnace.

The fuel-box is provided with an air-tight receivingdoor, d, figs. 1, 2, and 3, having suitable fastenings, and

a valve, e, iig. 2, opened and closed by a link, f, fig. 2, and a valve-rod, which passes through a packing in the fuel-box. l

A piston-head, g, with its rod, lt, (see iig. 2,) serves to thrust the fuel forward in the fuel-box, so that it may all fall into the furnace, through the aperture closed by valve e, fig. 2.

By this arrangement, and its proper manipulation, which will be seen by inspection of the drawings, it is obvious that the fire may be replenished with fresh fuel, while there is the requisite pressure within the furnace and casing, needed to operate the engine, without reducing the. pressure or impeding the operation of the engine.

The furnace is provided with openings, a,fig. 1,be low the grates, and with others, a2, ig.,1, above the top of the fuel, through whichV air under pressure is supplied, by means hereinafter to be described, which air is introduced into the space contained between the outside casing b, figs. 1, 2, and 3, which next surrounds it'.

The working-cylinders, of which there are two, are located within and upon the casing, and upon opposite sides of the furnace.

These cylinders are `singlewacting, that is, the pistou of each is forced upward by admitting the compressed heated air and gases from within the furnace, beneath the piston; and both pistons being connected to the main shaft R, figs. l and 3, by cranks at right angles with each' other, the downward movement of each pis'- ton is produced by the upward movement of the other, acting through the shaft in connection with the balancewheel.

Each cylinder may be described as in two sections; the upper section A, figs. 1 and 2, standing above and outside of the casing or bed-plate, and being nished 1 enginepistons within their cylinders. The lower s ecl tion, B, figs. 3, 5, and 6, is within the bed-plate or casing.

' This section need not be bored out or finished, as' the extension-part F, g. 1, of the piston, which plays in the lower section of the cylinder, is not intended to come into' contact with it, and, when at the lowest point of-its downward stroke, leaves an end and an annular' clearance.

That part of the piston which is marked D, g. 1, is constructed nearly like steam-engine pistons, so far as packing is concerned, and does not need further 'ere planation than is afforded by the drawing.

' The piston-follower, c', g. 1, is the flange of the pipe or trunk, C, figs. 1, 2, and 3. In this trunk, the coni necting-rod or pitman, P, figs. -1, 2,'and' 3, plays, and is connected lto the piston-head by a joint, as shown in fig. 1, which is kept cool by free exposure to the atmosphere, and by lubrication, for which good facilities are afforded. The trunk v.passes through the upper head, fi, figs. 1, 2, and 3, of the cylinder', where it is packed with leather, and guided by the gland figs. 1, 2, `and 3.

The upper cylinder-head is furnished with a valve, o, fig. 1, which, when forced open-by the compression of the air in the annular' space between the trunk and the upper section of the cylinder, permits the said compressed air to pass intol the casing, through the valvelboil: K and pipe L, figs. l and 2. It will be obvious that the piston', in its ascent, will compress the air in the said annular space, till its density is equal to that of the 'gaseous contents of thecasing, when further movement of -the piston upward, opens the outletvalve and displaees the -compressed air.

The upper cylinder-head is also furnished with valves, n, figs. 1, 2, and 3, the purpose of which is to open to admit air within the annular pump, when the pistonfdescends, and to close, and remain vclosed at other times. supposing the engine to be in motion, the air which is taken in hy the pumps and thrown out byeach stroke of each piston, passes, as is indicated by the arrows in g. 1, along the division-plate j, fig. 1, which extends horizontally, entirely across the space contained within the casing, to an opening in the centre of said plate ;v then, between said plate anda second horizontal plate,

k, figs. l and 2; from thence, downward between theouter vertical bonndary E.of the casing, and an internal vertical partition, on m, figs. 1 and 2, parallel with said outer boundary, and extending entirely-around within the casi-ng; then vertically upward between partitions m and l, figs. 1, 2, and 3, into a space contained between land t, figs. 1, 2, and 3, whence the air p asses into the furnace through-apertures al, figs. 1 and 2, and a,- fig. l, the position of the dampers fr, fig. l, determining what portion of the air shall pass into the furnace through the fuel, and what above. it.

Having described how air is compressed and forced into the furnace, I will now Ashow how,.when expanded by heat, it passes into the cylinders and is exhausted therefrom, thereby producing reciprocatifns of the -pistons, and developing the power generated -by-heating theair.

' In the top of the furnace, and passing through it to the inlet-valve boxes O, figs. l, 3, and 5, is a. suitablyshaped pipe, H, gsrl and 3, w'ith an aperture therein, opening in to the furnace, which can be opened and closed by a throttle-valve, p, fig. 1, This valve is 'operated by a governor .or regulator, Q, figs. 1 and 3, op-

. erating on a lever fixed to the valve-stem, by means of The heated air and gaseous theconnection 11,' fig. l. products lof combustion, mingled, pass into this pipe in amount regulated by the position of the throttle-valve, and when the inlet-valveof either cylinder .is opened, theypass `into the cylinder and force the piston upward.

:The inlet-valve, or valve correspondingto the steamalve of a steam-engine, closes when or before the pistimhas completed its upward movement. At about the time when the upward movement ofthefpi'ston ceases, and after the inletvalve has been closed, the exhaust-valve opens and permits the contents of the cylinder to escape, and to be forced out, by the Adescent of the piston, into the open air, vthrough the passage N, fig. 5and the radiator' or heater G, rigs. 1, 3, and

5, located in the space through which air passes on its.

.way to be heated in'the furnace.

The valves shown'in theA drawings are of the puppet variety, and areV operated, at -proper times, by liftertappets on the valve-rods, and on rocker-shafts worked from eccentrics S, figs. '1, 2, and 43, on themainlshaft. There is nothing peculiar about 'the valves or valvegcar, and any other which is adapted to the ingress and egress of the heated air, and known to engineers, in the Vpracticeof their profession, may be used for those shown, though I prefer to use valves of the pup-` petvariety.

The form ofthe heateris immaterial. That shown, presents a large surface for radiation, and the diaphragm-plates Acnfigs. l and 5, within the heater, compel -a tortuous passage ofthe exhaust.

It .will be' seen that the disposition of division-plates 'and partitions, before mentioned,-issuchl as to cause the gradual heating of the'cold, compressedair on its way from the pump to the'furnace, by the absorption of the heat from the radiation from the; lower part of the cylinder, the conveying-pipes, heater, and boundaries of.l the furnace, so that the radiated heat .is nearly all utilized, and the desideratum is attained-of' .having a comparativelyeool surface to the outer, or exposed surface and parts of the machine. A deadair space-is formed in the casing, betweenfits base-v plate and the compressed and heated' air, to prevent radiation of' heat from the lower surface .of the casing. At the junction of the upper and lower sections of'l the cylinder, and at the lower edge of'. the close-fitting part of the piston, a groove or chamber, fu, figs. 1 and 6,.is formed entirely around the cylinder. At the upper inner edge ef the lower section of the cylinder, is au inward-projecting `fiange, 's, figs. l and 6, which formsthebottom of the groove, and extends inward, from the general surface of the lower part ofthe cylinder, so as almost to touch the. lower, or extended' part of the piston.' The groove .or chamber around the cylinder', communicates with4 the compressed air in the upper part of the casing, where it is comparai tively cool and pure.

This communication` is made by the means of pipe w,'fig. 1, which terminates in the valve-box b', f i'g.'1, which the puppet-.valve u, fig. 1, operates by any vsuitable mechanism,.that shown being a wiper-or arm on a rocker-shaft, acting on the valve-stem, to open the valve against 'the pressure of a spring, the reaction of which assists to close it.

It will be seen that when the valve u, fig. l1, is open,

air will fiow into thecylinder from the casing at such spot as 4the valve may be located at. opened, as. it should be, after .the exhaust-valve closes, and before the mainl inlet opens, all the'- clearances or unoccupiedk space in the cylinder and valve-passages will be filled with pure air,'but little heated,'a1id of density'equal'to that within the casing and furnace.

The object of' introducing air through pipe w, fig. 1, from and at about the pla/ce, and at thetirne mentioned,

` is threefold with pure air, that which rushes, afterward, -into the` cylinder from thefurnace,` will not be apt to carry the solid .products of combustion into the joint` betweenthe finished portions of the piston and cylinder.

Third, by the introduction of cool compressed air,

as described, the temperature of the finished parts of' the piston and cylinder, which come into contact,are kept sufficiently cool toadmit of efficient lubrication.

The inwardly-projecting flange s, figs. 1 and 6, serves to deflect or to render difficult the passage of any particle of solid matter coming into the cylinder-with the heated air and gaseous products of combustin, and

the lower edge of the packed part of the piston is. l

If this valve is made of the shape shown in iig. 1, to aid in keeping regulated as to prevent the increase of pressure to a solid matter` from entering between the finished surpoint which would endanger the integrity of the mafaces of thepiston and cylinder, and from abrading chine.

tnem. It should be observed that the valve-chest covers, .The chamber e, gs. 1 and 6, serves to catch the oil through which pass the valve-stems, are provided with which passes by the piston, or` lubricating-matter may pipes T, fig. 5, which'extend through the casing, for the be injected therein, by an oil-pump. A pipe provided purpose of bringing the` packings of the valve-stems with a stop-cock, will aiford means for drawing oli acto a position where'they are not materially aifected by cumnlations `of lubricating-matter, together with such the heat from the furnace. solid matter as may be deposited there, while the lower Having described my invention, edge of the piston-packing, by dripping into the oil at What I claim as new, and desire to have secured to each downward stroke, will aid in keeping the workingme by Letters Patent, is` surfaces well lubricated. l. The combination and arrangement of the cylin- An improvement upon the simple chamber, consists ders, pistons, reservoir, and furnace, substantially as in placing therein a circular oil-trough, M, (see fig. 6,) herein made known.

which is sustained, at a little distance from the metal 2. The combination of the finished or upper part of'. of the cylinder, by ears placed at intervals around the the cylinder, with its head, piston, and trunk, therewith trough. connected, all operating together, and with inlet and The current of cool air from the aukiliary valve, will outlet-valves, and suitable packinground the said trunk, pass through the space around the trough, cutting-oli' to form an annular air-pump, substantially as set forth.

communication of the heat conducted by the metal of 3. The combination and arrangement of the chamthe cylinder, and preventing evaporation, and burning ber or groove 'u around the cylinder, substantially as of the lubricating-material. 1 specified.

In starting a fire on the grates, the main inlet, ex- 4. The construction and arrangement of the oilhaust, and throttle-valves should be opened, as well as trough M, within the chamber or roove, around and the ash-pit door, to establish a draught through the within the' cylinder, as herein set orth.

engine -by way of the cylinder and radiator. If' suf- 5. Theinwardly-projectingflanges, constructed, comfioient draught cannot be obtained in this Way, then bined, and arranged substantially as shown and dethe fuel-box valve e, fig. 2, and the door (l, figs. 1, 2, scribed.

and 3, should be opened, and a direct upward draught 6. The combination and arrangement of the vvalve thereby established, which may be conducted by a ternu, valve-box b', and air-passage w, whereby to admit porary funnel. comparatively pure and cool air 'om the reservoir, in

When the fn'el is well ignited, all the doors and valves .which it is constantly maintained compressed, at the through which air can pass to or from the casing, should place and times, substantially upon the principle herein be closed and secured, and air should be supplied by made. known.

a pump to support-combustion, and to force and com- 7. In an air-engine, in which the products of com, press air Within the casing, where it will be expanded bustion pass through the working-cylinder, the devices from the heat generated by the burning fuel. herein set forth, whereby to force the cool air from the The means by which air may be forced into thefurair-pump around and through all parts of the engine nace, while establishing a suicient pressure therein to liable to be `overheated by the intense heat from the start the engine, may be a force-pump, or fan, or other tire-pot, substantially as herein set forth. equivalent device, operated by hand, or by any other 8. The device and arrangement for sending the cool convenient and suitable power; or, the main shaft of air om the air-pump around and against the valves,

` the engine itself may be rotated by suitable-means, valve-boxes, and valve-stems, for the purpose of coolwhen thelpump forming part of the engine will supply ing them.

the air needed in the furnace. 9. The' combination of the valve p with the fire- ,When sufficient pressure has been generated to rochamber, hot-air passage H', and the regulating-device tate the engine, the extraneous force may be discon- Q q, whereby to govern the speed of the engine, as tinned, as the expansion of the air supplied by the herein set forth. f

pumps of the engine will continue to increase the press- PHILAN DER SHAW. ure 'within the casing, till the engine has some work Witnesses applied to it, to absorb the power generated. 4 WILLIAM EDsoN,

- Asafety-valve may be applied to the casing, and so ALBERT L. MuRDocK.

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