US2122704A - Suction vaporizer - Google Patents

Description

July 5, 1938. E. c. WELBORN ET AL SUCTION VAPORIZER 2 Sheets-Sheet 1 Filed June 13, 1936 j v e Welbom,

Edgar; Peir GLVanEaer 392 M July 5, 1938.

E. c. WELBORN El AL 2,122,704

SUCTION VAPORIZER Filed June 15, 1936 2 Sheets-Sheet 2 [ll/67% Eojgcufl Wiborm P192197 0 L mfiaeren,

Patented July 5, 1938 UNITED STATES PATENT OFFICE SUCTION VAPORIZER cago, Ill.

Application June 13, 1936, Serial No. 85,070

\ 19 Claims.

Our invention relates in general to the vaporization and combustion of fuel oils. It relates more in particular to a method of and apparatus for vaporizing relatively heavy liquid hydrocar- 5. bons, premixing the vapors with air and burning the same.

In the prior application of Charles A. French, Serial No. 47,910, filed November 1, 1935, there is disclosed a method for vaporizing relatively '10 heavy liquid hydrocarbons preparatory to burning the same. Relatively heavy liquid hydrocarbons as described in the French application are those heavier than kerosene, for example those having a Be. gravity of 41 or less.

15 In accordance with the French method of vaporization, an excess of fuel is maintained in a vaporization chamber and a controlled amount of products of complete combustion is delivered to the vaporization chamber into contact with the excess of fuel. The products of vaporization admixed with hot inert gases are then drawn from the vaporization chamber and mixed with a supply of air suiflcient for complete combustion, the products of complete combustion of a portion of 25 this mixture being utilized for vaporization purposes.

The principal object of our present invention is to improve processes for vaporizing relatively heavy liquid hydrocarbons.

30 Another object is the provision of improved apparatus for vaporizing relatively heavy liquid hydrocarbons.

Another object is to secure a greater range of operation of a fuel oil vaporizing device, particu- 3' larly such that a lower turndown thereof is made possible, that is the device can be set to vaporize only a very small fraction of the fuel oil which it is capable of handling at maximum capacity.

40 Other specific objects of the invention will be apparent from the description of embodiments herein described in connection with the accompanying drawings, wherein Fig. 1 is an elevational view partly in section, showing one embodiment of apparatus in accordance with our present invention;

Fig. 2 is a plan sectional view taken on the line 2-2 of Fig. 1, part of the equipment being shown in full lines to facilitate the disclosure; 50 Fig. 3 is a fragmentary elevational View showing a modification of the invention; and

Figs. 4 and 5 are partiallly schematic elevational views showing certain control features.

In accordance with the main features of the 55 invention, we employ a vaporizing chamber in which an excess of ,fuel is maintained at all times; that is, more fuel than can be vaporized at any given time by the heat available at such time and such place.

One suitable method is to maintain a pool of 5 oil in the vaporizing chamber, the constant level thereof being maintained by a float valve or other means. A blower is employed to withdraw vaporized fuel from the vaporization chamber and mix the same with air in a mixing chamber disposed between the vaporization chamber and the blower. A portion of the mixed fuel vapors and air is withdrawn from the manifold at a point on the pressure side of the blower and burned in a pilot flame, the hot gases of combustion from the pilot flame being brought into contact with the fuel in the vaporization chamber to promote vaporization. In general, the regulation of temperature of hot gases, the functions and, broadly speaking, the method of vaporization are substantially the same as described in the French application referred to hereinabove. The blower, pilot burner and mixing chamber are housed in an oven of special design and construction, the oven being heated by hot gases from the pilot burner.

There are several ways in which the principles of the invention can be utilized, some embodiments being shown in the accompanying drawings. For convenience, reference will first be made to Figs. 1 and 2, illustrating a relativelysimple embodiment wherein the controls employed are not shown in detail. Some of the functions and main advantages of the present invention will be pointed out more in detail after the description of the herein exemplified embodiments.

Referring now to Figs. 1 and 2, We provide a vaporization chamber H] in which a pool of oil at constant level is maintained by a float valve I l. The top of the vaporization chamber projects into a specially designed oven 12, and within the oven an extension l3 of the vaporization chamber is provided having a connection to a mixing chamber indicated generally by the reference character [4.

A pilot burner 16 extends through the wall of the oven 12 so that the flame from the pilot burner is disposed entirely Within the oven. The pilot flame is directed into a horizontally disposed portion of a conduit ll, the conduit extending through the upper extension l3 of the vaporization chamber and having a downcomer portion Ila, the lower end of which extends below the level of fuel in the vaporization chamber. In the portion of the conduit ll outside of the vaporization chamber there are provided a plurality of ports l8 through which hot gases in excess of those required for vaporization are delivered into the oven l2 gases as introduced into the oven being discharged from the oven through ports I8a.

One end of the mixing chamber [4 is connected to a blower housing I9 at the suction side thereof, in this case at the center of the blower. The opposite end of the mixing chamber is open to atmosphere to provide an air intake which projects through the wall of the oven. A control for the admission of air is provided as will be explained more in detail hereinafter. Intermediate the ends of the mixing chamber [4 there is an annular portion 2|, to which annular portion the top of the vaporization chamber extension I3 is connected through a throat 22, a butterfly valve 23 being provided in the throat to control the cross-sectional area thereof. The'airpassageway to the mixing chamber is constricted by means of an annular inner flange 24 whereby to facilitate mixture of air and vapor.

Within the blower housingl9 are fan or blower blades 26 secured on a shaft 27 journaled in the blower housing and extending through the outside wall of the oven I2. The pressure side of the blower is connected into a manifold 28. The blower is driven by an electric motor 29, a plural part coupling 3! being employed to avoid transmission of heat from the blower to the motor along the shaft, whereby to avoid overheating of the motor.

Manifold 28'extends out of the oven l2 and is adapted to deliver a combustible mixture of air and vapor to a point of use as, for example, to a burner 32.

The pilot burner is supplied with a combustible mixture from the manifold at the pressure side of the blower, a robber tube 33 extending into the manifold and connecting to the pilot burner it through a control valve 34; the control valve has connected thereto a rod 36which can be controlled by hand but preferably automatically as will be explained. I

To control the admission of air to the mixing chamber l4, we provide a perforated plate 31 entirely covering the outer end of the mixing chamber. Within this plate is a second plate 38 also perforated and mounted on a rod extending through and journaled in the plate 31. A lever 39 is provided for rotating the plate 38 so as to bring the openings in the plates 31 and 38 in alignment with each other or operated whereby by a species of valve action to control the cross sectional area of the parts through which the air passes to the mixing chamber and thereby to control the amount of air delivered under any particular conditions.

Due to the greater turndown possible with the device of our present invention, there are times that, unless precautions are taken, the temperature of the oil in the vaporization chamber will drop so that vaporization will not take place readily. To meet this situation, we provide a heating element 4! immediately below the vaporization chamber and in contact therewith, this element being controlled by thermostat 42 whereby when the temperature drops below the temperature at which the fuel is vaporized, electricity will be delivered to the heating element 4| until the temperature rises to the point at which vaporization takes place. It is, of course, understood that mere maintenance of a sufliciently high temperature will not cause vaporization in the present device, or at least not a substantial amount of vaporization. The essential element is the entraining of vapors with the hot products of combustion which pick up the vapors and carry them to the mixing chamber in somewhat the same manner that dry warm air will pick up water vapor.

Before describing the operation of the embodiment shown, we shall first describe other embodiments and control features in order that all of the advantages and features of the invention as a whole may be explained together.

In the device shown in Fig. 3, the same features are employed as in Figs. 1 and 2, except for certain modifications. In this form, the vaporizing chamber 36 is substantially entirely housed in the oven '51. A pilot burner dais directed downwardly to an orifice d9 in an insert of heat resisting alloy steel, imbedded in a downcomer The vaporizing chamber is partly jacketed with a jacket 52 having an annular opening 53 in the bottom thereof. A-portion of the hot gases flow down around the vaporization chamber inside of the jacket 52 and then through the annular opening 53, thereby heating the upper part of the vaporization chamber and imparting super heatto the vapors as they pass to the mixing chamber. An air intake is provided at 54 similar to the air intake described in the preceding embodiment, and the air from the intake 54; passes to a passageway 56 leading to an inlet 57 in a blower housing 58. A connection 59 is provided between the vaporizing chamber and the end of the air passageway where it meets the blower housing; and an annular flange 55 is provided at the orifice leading into the blower housing whereby to facilitate delivery of the proper mixture of air and vapor to the housing. A butterfly valve 62 is provided in the connection 59 tocontrol the effective cross-sectional area thereof. The blower is provided with the usual type of impeller blades 63 drivenby shaft 6 3 journaled in the housing. A portion 66 of a coupling is shown adapted to cooperate with a secondcoupling member driven by an electric motor, not shown, whereby to drive the blower and prevent overheating of the motor. The mixture delivered to the blower is exhausted into manifold 67, and a robber tube 68 is provided in the manifold for delivering a portion of the combustible mixture back to the pilot burner 68 A valve 69 is provided for controlling the amount of combustible mixture delivered to the pilot burner.

Figs. 4 and 5 illustrate control features and in order to simplify the showing, the oven with which it is preferred to house the entire apparatus is not shown. In addition, the relative arrangement of the parts is modified slightly to facilitate illustration in single figures, but each of these figures illustrates the embodiment of Fig. 1. For convenience, therefore, the portion of Figs. 4 and 5 which are identical with Fig. 1 and which bear the same reference characters will not be described in detail.

Referring now to Fig.4, a relatively small pipe or tube H has one end connected to the manifold 28 and the other end connected to one side of a diaphragm housing 13 containing .a diaphragm 12. The diaphragm is connected to a rod M which in turn is connected to a bell crank lever or arm 16 pivoted at T? to a stationary member 18 which may be part of a frame. A tension spring 19 has one end connected to the lever- 16 and the other end connected to the diaphragm housing whereby normally to urge the lever iii in a clockwise direction about the fulcrum l1.

The upper end of the bell crank lever 16 has a pilot burner control rod Bl pivoted thereto, the opposite end of the rod being adjustably connected to the arm 36 which adjusts the position of valve element 3 this valve element being suitably a butterfly unit. Similarly, a quality control rod 82 is connected to lever 16 and has its opposite end adjustably and pivotally connected to an arm 83 operatively connected to the butterfly valve 23 which controls the effective cross-sectional area of the throat 22. An air control rod 84 is also pivotally connected to the arm 16 and is adjustably connected to the air control lever 39 which controls the position of the adjustable perforated plate 38.

Fig. differs from Fig. 4 in the employment of a servo mechanism in the form of a pilot diaphragm mechanism. In this form, a tube 86 is connected to the manifold 28 and to one side of a diaphragm housing 88 containing diaphragm 87. A valve control rod 80 is attached to the diaphragm so that the movement of the diaphragm adjusts the position of a valve 9|. Compressed air is delivered to a pipe 92, and the amount of air passing valve 9| is controlled by the position of the diaphragm 81. The pipe 92 extends beyond valve 9| to one side of the diaphragm 12 in the housing 13. It also carries a fixed bleeder orifice 90. In this manner, the diaphragm 12 is controlled by pressure means independent of the manifold pressure, but the amount of air delivered to the diaphragm 12 is controlled by the manifold pressure through the pilot diaphragm 87, and'the bleeder 90. The control of the pilot burner, quality damper and air intake from the diaphragm 12 are the same as described in connection with Fig. 4.

There is a difference in operation of the forms of control shown in Figs. 4 and 5 which will be brought out clearly in the description of the operation.

Referring now generally to the operation of the device shown in Figs. 1 and 2, the same principles in general apply as those described in the prior French application identified hereinabove. There are certain differences, however. which make it advisable to explain. the operation to those skilled in the art in a somewhat detailed manner.

A relatively heavy liquid hydrocarbon such as a No. l to No. 3 fuel oil or heavier is maintained in the vaporization chamber I 0. While this form of device utilizes an excess of fuel in the form of a puddle or pool of oil, the same principle of operation applies if an excess of the oil is sprayed into the vaporization chamber, or a fountain principle employed, the characteristic in each case being that an excess of fuel is always present and there is a relatively large area of contact between the hot gases and the fuel. Whatever the manner may be in which the excess of fuel is maintained in the vaporization chamber, the fuel in liquid form is kept out of contact with surfaces substantially hotter than the liquid oil which would cause carbonization, and in no sense is the principle of vaporization in contact with an extremely hot surface employed.

The fuel oil is vaporized in the vaporization chamber and is drawn by means of the blower into the mixing chamber M where it is admixed with incoming air. This mixing is accomplished in a rapid manner by the structure shown. We have determined that if a No. 1 to No. 3 fuel oil is employed, condensation of the vapors mixed with hot products of combustion only is avoided if the temperature is maintained not lower than approximately 550 to 600 F. If now, this vapor be mixed with air sufficient for complete combustion, that is to say, if a perfect mixture is made, the temperature of the mixture can be as low as from 200 F. to 250 F. without condensation of the fuel vapor. It is, of course, understood that when the mixture is leaned out, that is to say, when a smaller proportion of vapor is present, the temperature at which condensation of the fuel vapors occurs is decreased; and conversely, if the mixture is richer the temperature at whichcondensation occurs is higher. It is essential, therefore, that a rapid mixing occur so that the vapor be not cooled by the incoming air to a temperature below about 550 to 600 F. before it is diluted with the air. It will be noted that the flange 24, which, on account of being in contact with the incoming air, is relatively cool, is not directly in the path of the vapors delivered to the mixing chamber through the throat 22. We have found that if the hot vapors entering the mixing chamber contact with any part carrying incoming air, condensation of the vapors occurs at that point. Although the mixer shown in Fig. 1 is constructed to deliver the air at a relatively higher rate of speed through a constricted passageway shaped after the manner of a Venturi tube, it is not primarily an injector effect which is sought but a mixing effect, the desire being to obtain the rapid mixing found to be required and a rapid interchange of temperature while still preventing condensation of the fuel vapors.

From the mixing chamber the air and vapor mixture is drawn through the mixing chamber extension into the blower and thence delivered under pressure to the manifold 28. The blower may be of a positive type or it may be a centrifugal blower as illustrated in the drawings. In the form of device shown in Figs. 1 and 2, the air and vapor mixture is heated in the mixing chamher and in the blower because of the oven arrangement. The heating of the blower is of particular importance because otherwise condensation tends to occur due to the centrifugal action. With the arrangement employed, however, the blower still further mixes the air and vapor mixture so that a very uniform combustible product is produced.

The advantages and functions of the present invention may be explained by reference to the blast type of vaporizer disclosed in French application, Serial No. 47,910.

As contrasted with the blast type vaporizer, the present form of device makes possible a much greater turn-down when an injector is substituted by a mixer-blower. In the injector type, when the back pressure in the manifold rises due to reduced consumption at burners or other devices utilizing the combustible mixture, the injector suction is reduced with the result that insuflicient vapor is withdrawn from the vaporization chamber to make possible an extremely low turndown. In the case of the mixer blower, the amount of suction on the vaporization chamber is under complete control by means of the valve in the air intake. This valve and the quality valve control the quality of the mixture in the manifold, as well as the pressure. With the present device, the air may be substantially entirely cut off, and the product delivered to the manifold will be substantially 100% fuel vapor, mixed, of course, with inert gases. With an extremely rich mixture, approaching 100% vapor, it is to be understood, of course, that additional air must be introduced' in the pilot burne'r'so as to support combustion at this point, but sufficient air should not be introduced to produce an oxidizing flame which would carbonize the liquid fuel in the vaporization chamber. Similarly, a product may be delivered to the manifold which consists substantially entirely of pure air, this being. accomplished by cutting off the connection between the mixer and vaporization chamber by means of the quality damper 23. These extreme controls, of course, do not represent practical operating conditions but merely illustrate the extent of control which is possible. Whether the combustible mixture is" on the extremelean side or on the extreme rich side, the quantity delivered to the manifold may also be controlled while constant quality. is maintained. In connection with the operation of the vaporizer'under extreme conditions of mixture, that is, with an extremely lean mixture or an extremely rich mixture, it should be borne in mind that the pilot burner may, if desired, be fed with a combustible mixture from a source outside of the vaporizer with which it is associated. In practice, a relatively small vaporizing device adjusted to produce a substantially perfect combustible mixture may be used to pilot a number of larger Vaporizers, and the quality of mixture produced in these sepa rately piloted Vaporizers can be controlled without introducing any complications whatsoever in the control of the pilot flame.

With the present type of vaporizer much less power input is necessary due in great part to the elimination of relatively high blast pressures. In the suction type of vaporizer, the total pressure differential between the manifold and suction sides of the blower need not be greater than approximately six inches on a water column, whereas the required differential in the pressure type of vaporizer is about 17 to 24%; inches of water. In the pressure vaporizer, the blast pressure on the blast line in ordinary operation is about 12 to 16 ounces, or 29 to 28 inches of water. The total back pressure in units which'have been operated successfully, employing the suction principle, ranges from 1 inches manifold pressure at high fire to 3% inches at low fire with one form of control. The suction at the suction side of the blower where it is connected to the mixing chamber is about 2 inches at high fire and 4; inch at low fire. It will at once be apparent that these figures show a total pressure differential of less than 6 inches on a water column in actual practice, but we have calculated that under substantially any ordinary conditions of operation not more than approximately 6 inches pressure differential between the suction side of the blower and the manifold is required for thoroughly satisfactory and commercial operation. With another form of control, the manifold pressure can be maintained substantially constant, but there will still remain a pressure differential at opposite sides of the blower approximately of the order illustrated above. Two different methods of control will now be described.

In the form of regulating mechanism employed in Fig. 4, the manifold pressure is applied directly against the diaphragm 12, so that at high fire and low fire a different manifold pressure is maintained and in response to such manifold pressure the position of the pilot valve, quality damper, and air control valve are adjusted. We have found that approximately 1 inches pressure variation on the water column is ample to operate a diaphragm and control the three adjustments described. As an example of this method of control, assume that a number of burners are supplied with a combustible mixture from the manifold 28. If now one or more of these burners is turned the pressure in the manifold increases. This causes the diaphragm 12 to move the arm 16 against the pressure of spring and decrease the amount of air and amount of vapor delivered to the mixing chamher. This at once tends to compensate for the decreased a-mount'of combustible mixture consumed by cutting down the amcunt of air and decreasing the amount of vapor fed to the mixing chamber. At the same'time, the pilot burner is maintained substantially constant, or the amount of combustible mixture delivered thereto decreased somewhat'by the control of the pilot valve. The entire equipment is maintained in equilibrium and the quality of the mixture delivered to the manifold remains constant. Conversely, if burners are turned on the manifold pressure tends to be decreased, the spring 19 returns the diaphragm, arm 16 and associated mechanism to a balanced position; and 'the quality and capacity'are maintained to-take care of the added load.

The formof control employed in Fig; also makes use of the manifold pressure except that only very slight differences in manifold pressure are employed, and the device is so arranged that a substantially uniform manifold pressure is maintained. In this case, assume that a burner is turned off and the pilot diaphragm 81 is actuated to open valve 91' slightly. under pressure is then delivered to the diaphragm l2 and the controls are operated to maintain proper quality and to establish conditions within-the mixing chamber or extension of the. mixing chamber where it engages the blower so that the manifold pressure beyond the blower again becomes substantially the same as that which existed before the burner'was turned off. This is permitted because the added load on the spring I9 does not have to be carried by thepressure: of gas in the manifold itself but is carried by the compressed air delivered from an outside source; are designed so that a bleeder valve 9!! permits the escape of exactly the same amount of air as that delivered past valve 91 after an equilibrium is established. Since at low fire the tensionon spring 1-9 isgreater than at high fire, it follows that a higher pressure must be maintained in the line 92 When a higher pressure exists in line 92, mere air will tend to escape through the bleeder valve 90; This means that more compressed air has to be admitted through the valve 9!. However, the difference is so relatively slight that the pressure the manifold remains substantially constant. We have determined that a maximum differential of A; inch on a water column is sufficient 'tomaintain the necessary adjustments at extremely high fire and extremely low fire.

The adjustments discussed occur substantially instantaneously. So rapid is the automatic adjustment that if a burner isturned off, the regulating mechanism keeps up with the closing of the valve leading to the burner and by the time the burner is entirely extinguished an equilibrium condition has again been established. For con.- venience, however, the functions of the regulating mechanism are explained in steps, although in actual practice they occur substantially simul- The parts taneously. A feature of the regulating mechanism is that should the manifold pressure drop unduly because of a blower failure, for example, the air valve will immediately open and dilute the mixture of air and vapor to such an extent that it will not support combustion. Backfires, therefore, due to sudden manifold pressure drop because of blower failure or the like, cannot occur.

In the pressure type vaporizer, at relatively low turndown, backfires may occur with the result that a blow-out occurs into or through the vaporization chamber, and special precautions are required to avoid such blow-outs or blowdowns. We have found thatshould a back fire occur with the suction type of vaporizer, the backfire is stopped at the blower discharge due to the turbulence in the blower itself. The present blower also has the advantage of requiring less floor space because the mixer does not need a straight approach and straight discharge in order to rectify flow as does the pressure vaporizer employing an injector.

The use of the oven in the vaporizer of the present invention is of extreme advantage. With very low turndowns, additional heat is introduced into the various vaporizer parts and this heat counteracts for temperature losses at low turndown which would normally result in excessive amounts of condensation in the oil vapor generated. With the arrangement employed, this feature is self-compensating since when less vapor is being withdrawn through the throat 22, more hot gases from the pilot burner are delivered out through the ports 3. By this means, heat is introduced to parts which at relatively low turndown would ordinarily lose heat.

The vaporizing device of our invention will continue to operate at extremely low turndowns and will continue to function when all of the valves in the mixture manifold are turned off; that is to say, when the only vapor being burned or consumed is in the vaporizing device itself. In this instance, a minimum quantity of vapor is withdrawn from the vaporization chamber and all of the vapor so .withdrawn is burned at the pilot burner. A considerable portion of the heat produced by the burning of this vapor is utilized to heat the oven and maintain all of the parts in full operating condition. We have determined that at the extreme turn-down, something on the order of 10% of the hot products of combustion are utilized for vaporization purposes and the remaining portion is available to heat the oven. The proportion of vapor utilized for vaporization purposes at this extremely low turndown is considerably greater proportionately than during normal operation. The significant fact of the low turndown, however, is that it is possible to completely shut off all valves connected with the manifold, the only outlet therefrom. then being through the robber casting 33 (Fig. 2), and the vaporizer will continue to function and will be ready at an instants notice to supply the maximum demand which will be placed upon it at greatest capacity.

It will be noted that the vaporization chamber, or at least that portion thereof which contains the liquid fuel, is not included within the oven. For this reason, no matter what the temperature of the oven may be, the oil is never raised to such a temperature as to cause boiling or vaporization thereof except through contact with hot gases, and cracking and formation of carbon deposits will not occur. The temperature at which vaporization takes place in actual operation is about 320 F. for No. 1 furnace oil, while the initial boiling point of such oil is 365 F. In a similar manner, with N0. 3 oil the temperature of the oil in process is 480 F., whereas the initial boiling point of the oil is 509 F. The thermostatic control for maintaining the proper temperature in the fuel bowl has been described. It is obvious that since the part of the vaporization chamber containing the oil is out of the oven sufficiently so that its heat will not be transmitted to the oil, the oil will not be raised above the temperature at which it is desired to maintain it.

A modified method of heating is utilized in the device shown in Fig. 3. In Fig. l, the pilot burner is operated at a rate of combustion higher than is necessary for the gasification of liquid fuel. The excess heat, the proportion of which varies with the output of the vaporizer, is liberated into the oven which encloses the mixer, suction tube and blower housing. The excess heat, therefore, in part superheats the vapor as it is delivered to the throat 22, but principally heats the mixture of air and vapor in the mixing chamber I4 and blower housing. In the form shown in Fig. 3, the rate at which the pilot burner is operated is also higher than required for vaporization of the fuel. Here, however, the vapor and air are heated separately, the air because the air passageway surrounds the casing 52, and the vapor because the gases are directed by the casing or skirt 52 down around the upper portion of the vaporization chamber where the vapors pass through the passageway 59. In this form also, however, the blower is enclosed within the oven.

The functions and advantages of our present invention appear to be clear from the preceding description. One of the greatest advantages is the extremely wide range of capacities possible and the extreme flexibility in the maintenance of proper temperature conditions in a processing oven, for example. To illustrate, if a dozen burners should be employed with a single oven, all fired by our present vaporizer and device, all, any number or none of said burners can be operated at any given time or for any given period and, whatever the condition may be, the vaporizer is always prepared for maximum increase or decrease in output and, whatever the demand made upon it, it will function automatically and substantially instantaneously.

What we claim as new and desire to protect by Letters Patent of the United States is:

1. In apparatus for vaporizing relatively heavy liquid hydrocarbons, a vaporizing chamber, means for maintaining an excess of the liquid hydrocarbon in said vaporizing chamber, means for delivering hot inert gas to the vaporization chamber into contact with said excess of liquid hydrocarbon whereby to vaporize a portion thereof, a manifold adapted to contain vapor under pressure and convey the same to a combustion device, a passageway connecting the vaporization chamber and said manifold, and a blower disposed in said passageway, whereby to withdraw vapor from said vaporization chamber and deliver the same under pressure to said manifold.

2. In apparatus for vaporizing relatively heavy liquid hydrocarbons, a vaporization chamber, means for maintaining an excess of the liquid hydrocarbon in the vaporization chamber, means for delivering hot inert gas to the vaporization chamber into contact with the excess of liquid fuel whereby to vaporize a portion thereof, a mixing chamber, a connection between said vaporization chamber and the mixing chamber, a part for admitting air to the mixing chamber, a manifold, a connection between the mixing chamber and the manifold, a combustion device having a connection to the manifold, and a blower disposed between the mixing chamber and the combustion device.

3. A device for vaporizing relatively heavy oils which comprises a vaporization chamber, means for maintaining an excess of oil in said vaporization chamber, means for introducing hot inert gaseous products of combustion into said vaporization chambeninto intimate contact with said oils, a manifold communicating with said vaporization chamber and leading to a combustion device, a blower disposed between said vaporization chamber and said combustion device, and

.means for withdrawing a minor portion of the Vapors passing through said manifold prior to reaching said combustion device, burning said withdrawn vapors, and means for passing the hot inert products of combustion resulting therefrom into said vaporization chamber whereby additional quantities of said oils are vaporized.

4. The structure defined in claim 3 including eating means substantially surrounding said blower.

5. In apparatus for vaporizing relatively heavy liquid hydrocarbons, a vaporization chamber, a mixing chamber, a connection between the vaporization chamber and mixing chamber, adjustable means for admitting air to the mixing chamber, a blower having a suction side connected to the mixing chamber, a manifold connected to the pressure side of the blower, an oven surrounding said blower, mixing chamber and connection between the vaporization chamber and mixing chamber, and means for heating said oven.

6. Apparatus as defined in claim 5 including means for maintaining an excess of liquid hydrocarbon in the vaporization chamber, a pilot burner, means for withdrawing a combustible mixture from the manifold and delivering the same to the pilot burner, and means for delivering hot inert products of combustion of the pilot burner into the vaporization chamber into contact with said excess of liquid hydrocarbon.

'7. Apparatus as defined in claim 5 including means for maintaining an excess of liquid hydrocarbon in the vaporization chamber, a pilot burner, means for withdrawing a combustible mixture from the manifold and delivering the same to the pilot burner, and means for delivering hot inert products of combustion of the pilot burner into the vaporization chamber into contact with said excess of liquid hydrocarbon, said means for heating the oven comprising means for by-passing a portion of said hot inert gases into the oven.

8. In apparatus for vaporizing relatively heavy liquid hydrocarbons, a vaporization chamber, means for maintaining an excess of liquid hydrocarbon in the vaporization chamber, means for introducing hot inert gases into the vaporiza.

tion chamber into contact with said excess of liquid hydrocarbon whereby to vaporize a portion thereof, a mixing chamber having a connection to the vaporization chamber for delivery of vapors to the mixing chamber, an air intake in said mixing chamber shaped to deliver atmospheric air to the mixing chamber in response to suction thereon, the delivery end of said air intake means being so arranged as to be outside of the direct path of the hot hydrocarbon by to impart heat to the mixed air and Vapor 3 to inhibit condensation of the latter.

10. Apparatus as defined in claim 8 including means for separately heating "thehydrocarbon vapor and air before the admixture thereof.

11. In apparatus for vaporizing a relatively heavy liquid hydrocarbon a vaporization chamber, means for maintaining an excess of the liquid hydrocarbon in the vaporization chamber, a mixing chamber, a passageway interconnecting the vaporization chamber and the mixing chamber, a port for admitting air to the mixing chamber, a blower connected to'withdraw mixed air and vapor from the mixing chamber, a manifold connected to the pressure side of the blower whereby to receive a combustible mixture of vapor and air under pressure, a pilot burner, means for withdrawing combustible mixture from the manifold and delivering the same to the pilot burner, and means for directing hot inert products of combustion from the pilot burner to the vaporization chamber into contact with said excess of liquid hydrocarbon.

12. Inapparatus for vaporizing a relatively heavy liquid hydrocarbon a vaporization chamber, means for maintaining an excess of the liquid hydrocarbon in the vaporization chamber, a

mixing chamber, a passageway interconnecting the vaporization chamber and the mixing chamber, a port for admitting air to the mixing chamber, a blower connected to withdraw mixed air and vapor from the mixing chamber, a manifold connected to the pressure side of the blower whereby to receive a combustible mixture of vapor and air under pressure, a pilot burner, means for withdrawing combustible mixture from the manifold and delivering the same to the pilot burner, means for directing hot inert products of combustion from the pilot burner to the vaporization chamber into contact with said excess of liquid hydrocarbon, and means responsive to the manifold pressure for controlling the amount of combustible mixture delivered to the pilot burner.

13. In apparatus for vaporizing a relatively heavy liquid hydrocarbon a vaporization chamber, means for maintaining an excess of the liquid hydrocarbon in the vaporization chamber, a mixing chamber, a passageway interconnecting the vaporization chamber and the mixing chamber, a port for admitting air to the mixing chamber, a blower connected to withdraw mixed air and vapor from the mixing chamber, a manifold connected to the pressure side of the blower whereby to receive a combustible mixture of vapor and air under pressure, a pilot burner, means i amount of air and amount of vapor delivered to the mixing chamber, said control means functioning to maintain the manifold pressure substantially constant independent of the amount of combustible mixture delivered thereto.

14. The method of vaporizing a relatively heavy liquid fuel oil which comprises maintaining an excess of the liquid hydrocarbon in a vaporizing chamber, delivering hot inert products of substantially complete combustion to the vaporization chamber, into contact with said excess of liquid fuel, withdrawing a portion of said vapors by suction of a suction device from the vaporization chamber, withdrawing atmospheric air by suction of such suction device into intimate contact with the withdrawn vapors so as to cause a quick intermingling of the air and vapors, and delivering the resulting combustible mixture under pressure through the suction device and through a manifold to a combustion device.

15. The method defined in claim 14 wherein said hot products of complete combustion are provided by a pilot burner, and wherein the combustible mixture burned in the pilot burner is withdrawn from the manifold.

16. The method defined in claim 14 including the step of heating the combustible mixture before delivery to the manifold.

1'7. The method defined in claim 14 including the step of separately heating the air and vapor before mixing them and prior to delivery to the manifold.

18. A device for vaporizing relatively heavy oils which comprises a vaporization v chamber, means for maintaining a pool of oil in the vaporization chamber, means for introducing hot gaseous products of combustion into a vaporization chamber beneath the pool of oil therein, a mixing chamber, a connection between the mixing chamber and the vaporization chamber, a connection to the mixing chamber with a source of outside air, a manifold connected to the mixing chamber, a pilot burner adapted for providing the said hot gaseous products of combustion, a connection between the pilot burner and the manifold, a combustion device, and a blower disposed in the manifold between the mixing chamber and the combustion device, the suction side of said blower facing said mixing chamber and the pressure side of the blower facing the combustion device whereby to deliver the combustible mixture under pressure to the combustion device whereby the combustible mixture passes through the suction means while flowing to the combustion device.

19. A device for vaporizing relatively heavy liquid hydrocarbon oil, which comprises a vaporization chamber, means for maintaining an excess of liquid oil in said chamber, a manifold, a mixing chamber, valved connections to the mixing chamber from said vaporization chamber and from a source of air respectively, a blower disposed between the mixing chamber and manifold whereby to withdraw mixed air and vapor from the mixing chamber, means for delivering hot inert gases into contact with the vaporization chamber in proportion to the amount of vapor withdrawn from such chamber, whereby it vaporizes a portion of the liquid oil therein, said liquid oil being heated by contact with said hot inert gases, and separate means for heating the said liquid oil in said vaporization chamber When insufiicient hot gases are delivered thereto to e maintain the desired temperature therein. EDGAR C. WELBORN. PETER C. L. VAN BUEREN.

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