US1920907A - Steam generator for automotive vehicles - Google Patents

Description

1933- W. D. LA MONT STEAM GENERATOR FOR AUTOMOTIVE VEHICLES Filed July 28, 1927 4 Sheets-Sheet l INVENTOR #4405? DOUGLAS L/Wm/T ATTORNEY5 Aug, 1, W33. w. D. LA MONT STEAM GENERATOR FOR AUTOMOTIVE VEHICLES 4 Sheets-Sheet 2 INVENTOR /VAZ me fia/ams 1/; /7o/vr ATTORNEY) unlll wllunull Filed July 28, 1927 Aug, 1, 1933. w. D. LA MONT STEAM GENERATOR FOR AUTOMOTIVE VEHICLES- Filed July 28,1927 4 Sheets-Sheet 5 OOOOOOOD K QRNN INVENTOR M44715? DOUGLAS Z/i/70/V7' Aug. 1, 1933. w. D. LA MONT 1,920,907

STEAM GENERATOR FOR AUTOMOTIVE VEHICLES I Filed July 28, 1927 4 Sheets-Sheet 4 fag/5? Patented Aug. 1, 1933 STEM GENERATOR FOR AUTOMOTEVE VEHICLES Walter Douglas lLa Mont, Larchmont, N. Y., as-

signor to La Mont Corporation, New York, N. Y., a Corporation of New York Application July 28, 1927.

(Cl. 186l) 7 Elaims.

This invention relates to processes and apparatus in which steam is generated in tubes of relatively small diameter as compared with water tubes andfire tubes commonly used in commercial boilers.

In my United States Patent No. 1,545,668, July 14, 1925, and in my copending application, Serial No. 79,096, filed January 4, 1926, I have disclosed tubes into which the water to be evapo- 0 rated is introduced in quantities greater than the generating capacity of a tube but less than sufiicient to fill the tube and through which the generated steam and unevaporated water move towards the discharge end thereof with provisions for separating the steam from the water and continuously returning the water to the receiving end of a tube. In said patent and application the generating elements or tubes are arranged so that the level of the discharge end 9 is lower than the receiving end, using gravity to aid.in the flow of water through the tubes, and maintain a film of water on the surface of the tubes opposite to that exposed to the heat. Such arrangements increase the steam generating efficiency of boilers to which they are applied, whether the tubes are of relatively small diameter or are of the size now in general use. In my copending application, Serial No. 162,770, filed January 22, 1927, for instance, I have shown the invention applied to fire tube and wa ter tube boilers of existing types.

I have discovered, however, that gravity flow is not a necessary condition to the generation of steam involving what may be briefly called the La Mont principle as disclosed in said patent and applicalion. In fact, the tubes may be horizontal or may be inclined with the receiving end of the tube lower than the discharge end.

4 In tubes so arranged, one condition is that the stantially horizontal position or in a position where the receiving end is below the discharge end, that the inner surfaces of the tube throughout its entire length are constantly wetted. In

the tubes that I have thus far used, the inside diameter has been approximately of an inch, although for some uses smaller tubes would seem to be even better and possibly somewhat larger tubes may also be used. i

5 'Another condition is that the water be introduced into the receiving end of a tube in a quantity greater than the evaporating capacity of the tube and that the excess water he with-i drawn from the tube at such a rate that the 5 quantity of water flowing through the tube is tubes shall be of such a diameter when in a sub- Serial No. 209,02i

constantly less than suflicient to fill the tube, but at all times greater than the generating capacity thereof. Or stated in another Way, the quantity of heat received and size of the tube and the quantity of water introduced should be so related that both steam and water fiow through the tubes from the receiving end thereof with such turbulency and velocity that the inner surface of the tube is substantially constantly wetted throughout with a film of water and that at all times the tube is free from hydraulic pressure such as would cause steam locking or would interfere with the freedom of flow so that there is no danger of the tube burning out. The invention finds many useful applications, as for instance, in the generation of steam for automotive vehicles such as rail cars, locomotives, automobiles, including trucks, and in such applications the generating tubes are arranged in a substantially horizontal position.

As applied to locomotives, the invention offers advantages over present methods of generating steam since it will aiiord greater steam generating capacity for the same or less weight and since locomotives at the present time are necessarily limited to certain clearances and possibly weight, any increase in power without increasing weight or size is a distinct advantage.

In respect of other automotive vehicles such as trucks, coaches and pleasure cars, the steam motor has many well known advantages not possessed by the gasoline engine. Automobiles which have heretofore employed steam as a motive power have usually relied upon so-called flash boilers, that is to say, boilers in which all of the water injected into the boiler is immediately converted into steam, or boilers in which the water is boiled in substantial masses. The difiiculty of accurately and reliably controlling flash boilers has been a serious objection to their use and in the mass boiler type there has been difficulties with the formation of scale, often resulting in burn-outs.

By the use of the present invention, it is possible to generate steam at a sufficiently rapid rate and under simpler controls than is possible with the older type of boilers, thereby gaining the advantages of steam power in vehicles of this sort. Preferably, the La Mont generating tubes are arranged lengthwise of the vehicle and underneath the body thereof and extend for a substantial portion of the length of the vehicle.

The invention and its applications will be better understood by more detailed consideration of 11 0 the several embodiments illustrated by way of r the examples, in the accompanying drawings, which drawings, however, are more or less schematic and illustrate practical ways of applying the principles of the invention without including many details which would, of course, be supplied in practice by the designer and engineer for the more convenient and automatic control of various functions.

Referring to the drawings- Figure 1 is a side elevation showing more or less diagrammatically an automotive vehicle having the invention applied thereto;

Figure 2 is a section on line 2-2 of Figure 1;

Figure 3 is a section on line 3-3 of Figurel;

Figure 4 is a sectional view showing a somewhat difierent arrangement of the casing for the tubes to provide insulation and also to permit circulation of air, which is thereby heated before it is delivered to the combustion chamber;

Figure 4 is a modification of the construction shown in Figure 4;

Figure 5 is an enlarged view of the crosswise arranged insulation cells shown in Figure 1;

Figure 6 is an enlarged view of a modified form of means for subdividing the casing enclosing the tube casing proper to provide for the circulation around the tube casing;

Figure 7 is an enlarged view of one of the intake headers and intake manifold;

Figure 8 is an enlarged view of a discharge header showing its connection with the pot wherein the stream and water are separated;

Figure 9 is a side elevation of a somewhat modified arrangement embodying the invention;

Figure 10 is a section on line 1010 of Figure 9;

Figure 11 is a section on line 11--11 of Figure 9; Figure 12 is a top view partly in section of the form shown in Figure 9; and

Figure 13 is a diagrammatic view showing one way in which the various parts may be co-ordinated and controlled.

Referring to Figure 1, the frame of the vehicle may be utilized to support a casing for the steam generating elements. This casing is shown at 1 and extends from front to rear of the vehicle and preferably the under and upper portions are formed each of two plates separated by an insulating space. In the embodiment shown in Figure 1, the plates are separated by partitions 2, Figure 5, running transversely of the frame and providing dead air spaces. These partitions are preferably separated from the frame plates by strips 3 of heat-insulating material. The casing 1 is closed at the front by a plate 4 but the rear 5 is open and covered by a screen, through which the exhaust combustion gases flow. The usual hood is somewhat modified and consists of an inner casing 6 and outer casing 7, as shown in Figures 1 and 3, thus providing a space therebetween through which air may fiow to be utilized in promoting combustion. As shown, the combustion chamber occupies the major portions of the hood space and thus provides a combustion chamber of ample size. Not all of this space, however, need be thus utilized but only sufficient for the purpose of producing combustion gases at a sufficiently high temperature and in the desired volume. A fan 8 suitably supported on the front portion of the outer casing 7 forces air into and around the spacebetween the casings 6 and 7. The combustion fuel is supplied through a nozzle shown conventionally at 9.' Suitable means, not shown, are provided for burning the fuel within the casing or chamber 6, the flow of air being around the walls of the casing 6 and between it and the casing 7, suitable passages being provided so that the air enters alongside of the combustion nozzle 9. The hot gases then come in direct contact with the steam generating elements 10 and after passing lengthwise of the tubes are discharged through the screen 5 at the rear end of the vehicle.

The tubes 10 constitute the steam generating elements and are suitably supported within the frame and between the upper and lower members thereof. Several sets of tubes are shown arranged one above the other (Figures 1, 2 and 3) and each set of tubes is supplied with water for steam generation by a distributing tube 11 carried by a header 12. This distributing tube is shown in enlarged detail in Figure 7 and is semicircular in form with small orifices, one registering with each generating tube 10. For convenience of assemblage the headers 12 have holes bored therethrough and the end of each tube is expanded into the header. The distributing tube 11 may then be inserted into the header from one end thereof and plugs 13 are then inserted into the hole opposite the tube end. In this way steam-tight joints are provided and flow of steam and water in one direction assured.

The tubes 10 are of relatively small diameter, those which I have used being of an inch outside diameter and /g inch inside diameter. The tubes, however, have limits as to size dictated by the following considerations:

In general, tubes as small as possible are desirable because they will stand higher steam pressures with a thinner wall, than large tubes. They are therefore lighter and less expensive. on the other hand, where the tubes are exposed to radiant heat and where the advantage of close spacing of the tubes does not enter so much as a factor, since the heat transferred takes place mainly due to the elevation of the temperature of the heated body, somewhat larger tubes are desirable to provide for the introduction of a large amount of water necessitated by the corresponding high evaporation under the action of radiant heat. The use of a larger tube permits a larger orifice in the distributing tube, which is desirable to avoid the danger of clogging and insuring the introduction into the tube of suflicient water in excess of the evaporating capacity of the tube. The tube, however, must not be so large as to interfere with the proper propagation of the film by means of the steam and water fiow, since in a tube of too great diameter there is danger of hydraulic action, resulting in steam pockets with too large a surface of the tube unwetted and corresponding danger of burning.

When convection gases are used, as small a tube as possible is desired in order that a great number of tubes closely spaced may occupy a given cross section, thus providing for concentration of the heat surface in the cross section of the gas passage, thus increasing the rate of heat transfer. Another advantage in smallness of tube is the increase of heating surface obtained with as short a tube as possible. This is especially desirable where there is limitation of length of tube. A small tube under convection conditions may likewise be used because the evaporation is not so great as under radiant heat conditions and therefore the amount of water necessary to be introduced into the tubes is relatively smaller and even though the orifice in the tube is also smaller there is less danger of clogging. It is apparent. however, that the limit of smallness is reached when the orifice in the distributing tube orated by the tube.

The invention therefore is not limited to any exact size of tube but with due regard to the con ditions just outlined, should be relatively small.

The water for the generation of steam in the construction shown in Figure 1 is supplied to the intake distributing tube 11 in quantity less than sufiicient to fill the tubes but greater than the steam generating capacity of the tubes and by reason of the small orifices in the intake manifold the water is distributed in .proper proportion to all the tubes. The water supply is obtained from a tank 14 connected by a stand pipe 15 to a water distributing header 16, from which run branch pipes 17 for supplying each intake or distributing tube 11, of which four are shown in Figure 1. It is, of course, to be understood that the number of tubes will vary according to the power requirements of the particular vehicle upon which they are used. A pipe 18 also connects the header 16 to a pump 19 which constantly supplies the necessary head of water to the tubes 11, the size of the pump being so calculated that water in a proper quantity is delivered. Due in part to the'force of the water injected through the orifices in the tubes 11 and in part to the expansive force of the steam formed in the generating tubes, steam and water flow through the tubes to the rear or discharge end thereof with such velocity and interaction due to the process of ebullition in the small tubes used, that the inner surface of the tubes is constantly wetted and steam is rapidly formed and discharged from the water film formed on the tube surface. Steam and water are discharged into a pot 20, where the water is taken up by the pump and returned to the intake manifold and the separated steam passes into a pipe 21 to a throttle valve 22. When the throttle valve is opened steam passes through a pipe 23 to the engine 24 suitably supported as by a bracket 25 depending from the vehicle frame and by the rear axle of the vehicle. Other forms of support may, of course, be used. The exhaust steam from the engine flows along pipe 26 upwardly through a pipe 2'7 to a condenser 28. A pump 29 connected by a pipe 30 to the distributing header 16 delivers the condensed steam thereto.

In order to equalize pressure in the pot 20 and supply tank 14, a small pipe 31 connecting the two is provided, or a pipe with a restricted portion, as shown at 58, Figure 1.

With the piping arrangement as shown, when the pump 19 stops, the tubes 10 are filled with water from the tank 14. As soon, however, as the pump starts again the tank 14 begins to fill, due to the restricted orifices in the intake manifolds. When it is necessary to supply additional water to the system this may be conveniently done, through the tank 14, which is provided with a cap 32 for this purpose and the pipe 15 and pipe 31 are each supplied with a valve to enable the tank 14 to be entirely shut off from the system when it is being filled. Nor- 'mally both valves are open. I

The operation will be apparent from what has been already stated but it may be briefly summarized as follows: The fuel to be burned entering through the nozzle 9 is supplied by the fan with air for its combustion and the combustion gases after passing over the tubes 10 and heating 'them to the desired steam generating temperature, pass out at the opening 5. The tubes being of small diameter and of suitable length and likewise being closely spaced absorb the heat rapidly and efiiciently from the gases when the latter pass over them at high velocity,

and therefore comparatively little heat is wasted in the exit gases.

The water supplied by the pump 19 to the intake manifolds enters the several headers and is rapidly converted into steam as it passes along the tubes 10, the steam being separated from the water in the pot 20, the unevaporated water being returned again to the headers. The steam utilized in the engine is passed through the condenser and the condensed steam again also returned to the headers. The amount of water that needs to be supplied to the system is only that due to leakages which with proper design may be, and preferably is, very small.

The pump 19 is designed to be operated at sufiicient pressure to maintain the desired head of water in the tank 14, but even if this pressure should be a little greater than necessary, a small amount of water will be carried over to the pot 20, but only a small amount, due to the restriction 58 in the connection 31.

The insulation of the tube space both at the .bottom and top, as shown in Figure 1 and described above, is only one of a number of forms which might be utilized. Another form of cells is shown in Figure 6 and these may run either transversely providing dead air space, or they may run longitudinally. With the form of partitioning wherein the cells run longitudinally in-. stead of transversely of the frame, provision may.

be made for passing the air taken in by the fan through the casing before it enters the combustion chamber, thereby imparting heat to the air and effecting cooling of the casing plates, thereby preventing radiation loss, the heat thus absorbed being returned to the combustion space.

In Figure 4 is shown another arrangement consisting of two longitudinally celled casings outside of the casing carrying the generating elements. The inner passages in this figure are designated as 33 and outer ones as 34. The air supplied by the fan may be made to circulate first through the outer passages and then through the inner ones and thence to the combustion chamber or in some cases a reverse circulation may be used, that is to say, through the inner passages first and then through the outer ones and thence to the combustion chamber. Other arrangements may'also be used. For instance, some of the cells may be made smaller than others, as illustrated in Figure 4 and these may be closed against passage of air, thus providing dead air spaces at suitable intervals or these spaces may be filled with insulation. The closure may be permanent, or dampers may be used in some or all of the cells to control the draft. Still other arrangements may be employed. w The modification shown in Figure 9 does not have a condenser and hence a larger water supply is necessary than in the form of device shown in Figure 1. In this figure the frame of the vehicle consisting of channel bars is utilized to support the steam generating elements which are located in a casing having a lower member 35 and an upper member 36, each of which may and preferably does consist of a lower and upper plate between which insulating material is placed, or circulation cells such as shown in Figures 4 and 6 may be used. The channel bars of the vehicle frame may constitute the sides of this casing. In this form of device, the hood of the automobile is supported as usual by the frame and the frame at its forward portion is formed into a combus- 5 tion chamber indicated by the numeral 37, and

having a burner 38 suitably located therein. Suitable means not shown, but which may be similar to those shown and described in connection with Figure 1, may supply air for combustion, if dcsired. The heated gases, in the form of arrangement shown in Figure 9, likewise come immediately into contact with the tubes 10, and flow along the chamber formed by the members 35 and 36 to the rear end of the vehicle where they exhaust into the atmosphere. The tubes 10 are of the same type as illustrated in the first described form and they likewise are supplied with intake manifolds of the same construction already described. The rear end of the tubes, however, instead of running into a transversely extending pot, as shown in Figure 1, enter a discharge header 39 shown in enlarged view in Figure 8, which header is connected with a vertical pot 40 wherein the steam and water are separated, the steam going through a throttle controlled pipe 41 to the steam chest 42 of the engine 43 while the water entering the pct 40 passes through pump 44 and by way of pipe 45 back to the intake headers. Since no condenser is used, the supply of water is carried in a tank 4'7 occupying the hood space, which tank is connected at its lower portion by a valved pipe 48 with the pot 40. A small equalizing pipe 49 connects the upper portion of the supply tank 4'7 with the upper portion of the pot 40, a valve 50 also being provided in this pipe, which valve and also the valve 51 in the pipe 48, may be closed when it is desired to supply additional water through the opening closed by the cap 52. The engine is supported by a bracket 53 depending from the vehicle frame and by the rear axle, as in the first described form.

Although in the above described embodiments the flow of steam in the tubes is longitudinal of the vehicle, it is nevertheless within the spirit of the invention to arrange the tubes so that the flow of steam therein is transverse of the vehicle. Such an arrangement is made possible by reason of the small size of tubes which may be used according to the principles of the invention, and by reason of their small size more of them may be placed in a given space. Therefore a suflicient length may be available in the width of a vehicle to provide for suificient steam generating action. The gases, however, flow longitudinally, as in the forms described above.

Referringnow to Figure 13, which shows diagrammatically the several controls it will be assumed that the vehicle is stationary and that no fuel is being supplied and no air forced through by the fan. The steam generating elements 10, however, are filled with water.

Upon movement of a control lever 60 pivoted at 61 a link 62 rigidly connected to a portion 68 of the lever 60 rocks the bell crank lever 63 about its pivot and opens the valve 64 to admit fuel to the combustion chamber. This fuel may consist of any suitable liquid, such as crude oil or kerosene, which may be burned in any well known manner. Movement of the portion 68 of the lever 60 also closes an electric circuit through a motor 65 connected by a belt or otherwise for operating the circulation pump 19. The circuit for the motor may be traced as follows: starting with battery A, the current flows through the wire 66-67 to the shaft 61 or to a conducting collar on the shaft,

thence along the arm 68 which is also of conducting material and which arm at this time engages the contact member 69. From 69 the current flows along wire 70-'71 to the motor 65. Returning, the current flows along wire 72-73 back to the battery. The arm 68 also makes electrical contact with another contact piece 74 which supplies current through wire '75 to a sparking device 76 within the combustion chamber to ignite the fuel, a suitable sparking coil 7'? being provided in the circuit.

The initial movement of lever 60 in addition to establishing the several circuits already described and substantially simultaneously therewith also closes a third electrical circuit by the arm 68 coming in contact with an electrically conducting member '78, to which is connected a wire '79-80 leading to a rheostat 81. An arm 82 stands normally in electrical contact with one of the rheostat points and the current flows through this arm to wire 83 to the fan 8. All of the above described operations take place when the lever 60 is moved from the position shown in Figure 1, to a position coincident with a second lever 60a. It is to be understood, however, that the starting of the circulation pump, the fan and the supply of fuel and its ignition while all taking place during the initial movement of the lever 60, do not necessarily occur simultaneously, as it is preferable to arrange for the proper lag or lead in starting the several instrumentalities. Preferably the circulation pump is started first followed by starting of the fan and ignition of the fuel. It is of course, obvious that this order may be varied.

When the lever 60 is moved as described, the pump 19 has been started, fuel has been introduced into the combustion chamber and ignited, the fan circulates air for combustion and forces the heated gases over and along the generating elements, causing steam to be generated.

To start the engine, the lever 60a is moved in a clockwise direction, which lever operates through a link 84 on a second lever 85 controlling the throttle valve 22. Steam is then admitted from the steam pot 20 through pipes 21 and 23 to the engine 24.

The pump 29 which takes water from the condenser and discharges it into the water distributing header 16 is operated by a belt on the engine shaft so that upon starting of the engine, the condenser water is circulated.

If the lever 60 has been operated to perform its various functions and the lever 60a not operated, the result would be the generation of steam in the tubes 10, but no use would be made of it. A safety valve 86 is provided for emergency but in order not to waste steam unnecessarily a control is provided whereby the supply of fuel is cut down and the fan slowed down under these circumstances. This is brought about through a rise of pressure in the pct 20. A pipe 87 leading from the upper portion of the pot conveys pressure to a piston 88 to move a rod 89 connected to an arm forming a bell crank with the arm 82 to cut in resistance to the fan circuit, the movement being opposed by a compression spring 89. Likewise the pressure acts through a diaphragm. control 90 to cut down the fuel supply The order in which the different elements are brought into action, may likewise be varied.

For instance, with the tubes 10 full of water, the combustion may first be started and steam generated, as in the ordinary water tube boiler. The steam so generated may be used to operate the water circulating pump 65. Since the steam generated under these conditions would collect mostly in the tank 14, a connection from this tank would lead to a steam engine which would be substituted for the electric motor 19.

What is claimed as new is:

1. The combination in an automotive vehicle, a combustion chamber and steam generating elements extending longitudinally throughout a substantial portion of the length thereof, a casing enclosing said elements through which casing the heating gases may pass, a longitudinally celled casing outside said first mentioned casing and through which the air to be used for combustion passes before entrance thereof into the combustion chamber.

2. The combination in an automotive vehicle having a body, of steam generating elements extending under the body and throughout a substantial portion of the length thereof and means for positively maintaining circulation through said elements of water in quantity greater than the steam generating capacity thereof but less than sumcient to fill said elements.

3. In combination with a body and hood of an automotive vehicle, of steam generating elements extending outside of the hood, and a combustion chamber occupying a substantial portion of the hood for supplying the heat for said elements.

4. The combination in an automotive vehicle having a body and having a frame provided with a portion extending beyond said body, of steam generating elements arranged adjacent to the body, a combustion chamber arranged adjacent said extended portion of the frame, and means for causing the combustion gases to pass from the combustion chamber over said steam generating elements.

5. The combination with an automotive vehicle having a hood, of steam generating elements having at least a part of their length extending outside said hood along a portion of the vehicle, and a combustion chamber in the hood for supplying the heat for said elements.

6. The combination with an automotive vehicle of a plurality of steam generating tubes having at least a part of their lengths extending generally parallel to each other and longitudinally of the vehicle, a combustion chamber for supplying the steam generating heat for said tubes and so located in relation thereto as to deliver the gases of combustion to said lonigtudinally extending part of the tubes, and a casing surrounding said part of the tubes and connected to said combustion chamber so as to cause the heating gases to pass longitudinally of the vehicle lengthwise over said part of the tubes.

7. In combination with an automotive vehicle for normally horizontal travel, a combustion chamber mounted in the vehicle, a casing mounted in the vehicle and providing a gas passage having its lonigtudinal extent normally horizontal, said casing at one end thereof being connected to said combustion chamber so as to receive the combustion gases from the combustion chamber and to confine their flow lengthwise of the passage, a set of tubes mounted in said gas passage and having their lengths extending generally parallel to the lonigtudinal extent of the passage, whereby the flow of fluid through the tube is normally substantially horir'ontal and the flow of gases from the combustion chamber is along the length of the tubes toward the end thereof remote from the combustion chamber.

WALTER DOUGLAS LA MONT.

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