US2122683A

US2122683A - Oil vaporizer control

Info

Publication number: US2122683A
Application number: US710971A
Authority: US
Inventors: Clyde B Faverty
Original assignee: Individual
Current assignee: Individual
Priority date: 1934-02-12
Filing date: 1934-02-12
Publication date: 1938-07-05
Anticipated expiration: 1955-07-05

Description

July 5, 1938. c. B. FAVERTY OIL VAPORIZER CONTROL Filed Feb. 12, 1934 2 Sheets-Sheet l u: unil :as

July 5, 1938. c. B. FAVERTY OIL VAPORIZER CONTROL 2 Sheets-Sheet 2 Filed Feb. 12, 1934 K l 7s Patented July 5, i938 UNITED STATES OIL VAPORIZER CONTROL Clyde B. Faverty, Chicago, Ill., assigner, by mesne assignments, to Mark C. Bates, Chicago, Ill.

Application February 12, 1934, Serial No. 710,971

19 Claims.

My invention relates in general to oil Vaporizing and burning mechanism. It relates more in particular to control means for a vaporizer by means of which more accurate burner control and the like is obtained.

'Those skilled in the art are referred to the copending application of C. A. French, Serial No. 603,491 filed April 6, 1932 wherein apparatus is shown for vaporizing a liquid hydrocarbon such as gas oil". 'Ihe French vaporizer is of considerable utility particularly in certain industries for supplying a gas of a sufficiently stable character to permit its being piped short distances to industrial furnaces and ovens. For this reason, the equipment can be used to take the place of gas in industries where a close control of temperature and furnace atmosphere is necessary. Considerable saving results from its use. Certain disadvantages and objections, however, arise when the French equipment is used under certain conditions. For example, if a single vaporizing unit is employed to supply a combustible mixture to a plurality of furnaces or ovens, a problem has arisen in that when the combustible mixture is shut off to one burner, there is a tendency to supply an excessive amount of the combustible mixture to the remaining burners. So also, when the equipment is adjusted to supply less than the number of burners present, when additional burners are turned on there is a tendency for the supply of combustible mixture to the plurality of burners to be insuiiicient to maintain temperature. arise in connection with maintaining the proper relative mixture of air and vaporized hydrocarbon when a plurality of burners is supplied. Other problems in control are encountered. but in general the case of the use of a plurality of burners is typical and suiciently illustrative.

'Ihe principal object of my present invention is the solution of the problem indicated.

Another object is to provide an automatic control for vaporizing apparatus when the same is connected to supply a plurality of burners.

Still another object is the provision of improved vaporizing structure whereby pilot burner operation and operation of the vaporizer as a whole are enhanced.v y

Another object is the provision of an improved diaphragm control mechanism for regulating the supply of air to the vaporizing apparatus.

A further object is to maintain a substantially constant pressure in a manifold between an oil vaporizing apparatus and a burner.

A still further object is to maintain a substan- Additional problems tially uniform mixture of air and oil vapor in a manifold whether the vaporizing apparatus is operating at maximum capacity or short of maxtmum capacity.'

A further object is the provision of simple means for raising or lowering an established manifold pressure to suit variable operating requirements.

Another object is to control the output of a. vaporizer in response to manifold pressure. v

Still another object is to amplify the manifold pressure variation by means of pressure from a separate source.

I show and shall describe certain embodiments of my invention in connection with the French type of vaporizer heretofore referred to in describing problems sometimes arising in the use of this general -type of equipment) It will be evident to those skilled in the art that the invention may be used with many types of installations. It is particularly adapted, however, for' use when a French type of vaporizer is used to supply a plurality of burners placed in dliferent ovens or furnaces, each separately controlled as to temperature and operation. 4

According to the main features of the present' invention, I employ a diaphragm type of vaporizer control responsive to changes in manifold pressure so arranged that if one or more burners are extinguished or turned down, the amount of air and vapor delivered to the manifold is decreased, while the same proportions thereof are maintained. When a burner is turned on, the amount of air and vapor is automatically increased. Preferably I use a pilot control so that 35 air under pressure, controlled by the pilot, furnishes the operating pressure.

0n the French type of vaporizer, a tapered metering rod is movable axially of a forcing nozzle forming a part of an inspirator which draws oil vapor from a vaporizing chamber. The'yolume of air through the forcing nozzle is thus cut down without decreasing the velocity or impairing the suction on the vaporizing chamber. Co-incidentally with the operation of the metering rod, a valve is actuated to control the vapor passageway to the inspirator, and assists in maintaining a uniform air-vapor mixture.

Other objects and features of the invention will be apparent from a consideration of the following detailed description taken with the accompanying drawings, wherein 1 is an elevational view, partly in section, showing the features of the vaporizing apparatus and control therefor;

Fig. la illustrates more or less schematically a group of burners or ovens. the scale being made smaller than used in Fig. l;

Fig. 3 is an enlarged vertical sectional view taken through part of the control mechanism of F18. 1:

Fig. 3 isasectional view taken ontheline3-3 Pig. 4 is a modification of the control apparatus shown in Fig. l, wherein only a single 'dia-f phragm valve is employed; and

Fig. 5 illustrates still another modification in which control is based upon a different principle.

Now considering the details of the invention, I shall refer first to the general features of the vaporizer illustrated in Fig. 1 and thereafter shall describe the' control means therefor. Air under pressure is supplied from a blower, air pump, or suitable mechanism 0 to an air delivery pipe Il, whence it is delivered to an inspirator including a forcing nozzle Il and a. Venturi 'mixing nozzle I2. An annular ewayor gas 4distributing chamber I3 between the forcing nozzie and the mixing nozzle connects with a vapor eway H controlled in part by a. butterfly type of valve Il. 'Ihe passageway Il is: connected to a vaporizlng chamber I1 where' a constant level of liquid hydrocarbon is maintained by a iioat valve mechanism Il. .-'I'he vaporized hydrocarbon'or gas is accordingly 4drawn the passageway I4, combines with air as it passes through the mixing nozzle l2 to form a'combustible mixture and is delivered through' a larger passageway llconnected to and forming a of a manifold 2|. The lioat valve mechanism I3 is provided with a pipe Ila which is con nected with the vaporizing chamber l1 whereby equal pressure conditions are maintained in both the noat chamber and the vaporizing chamber. A pipe I8b connects the oat chamber with the lower part of the vaporizing chamber il to provide for the passage of the liquid hydrocarbon into said vaporizing chamber.

The eway l! is constructed in the form of-a casting in which is provided a trap 22 for withdrawing" some of theY combustible'mixture and supplying the same through a pipe 23 to a pilot burner indicated generally by the character 24. The mixture is burned and downwardLv' through a vertical passageway 2S. The integral passageway 23 is provided with an extension 21 carrying a bubble plate 28 di `beneath the level of the liquid. Here the hot gases of `combustion are broken up and pass upwardly through a plurality of openings in the bubble plate. In through the liquid hydrocarbon, the hot gases vaporize aportion of this liquid, and'the'vaporized Portion with the burned gases are drawn through the passageway I4 into the Venturi tube i2. This is ,the cycle of operation. it being understood, of course, that the major portion of the combustible mixture Passes to the' manifold 2| where it is :available for burning at a plurality of burners provided in ovens 29-29.

It will be noted that the casting is `constructed so that the trap opening 22 is positioned sutil- 'ciently above the lower inside surface thereof so that any vaporized liquid which mightv condense in the large eway I9 cannot find its way into the 4pilot burner. At a suitable place in the manifold, I also provide a trap 3| for catching any condensate that may form in this place. The trap is connected by a pipe system 32 to the vaporizing chamber il, softhat whatanaaeas ever condensate is formed is returned directly to the system. i

Inserted in the gas passageway to the pilot tube I provide a'valve system including a butterily type of valve 33 controlled by a handle 3l, with a calibrated segment to show the position of the butterfly valve and stops 33 which can be set to limit the movement thereof. By this means I can set the butterfly valve to produce any suitable and selected type of flame at the Pilot burner.

The burner 24 is of special construction to avoid the possibility of having the name thereof extinguished due to high velocity of the gas therethrough. To this end itis provided with a central'burner opening 31 and relatively smaller radially `disposed openings 33. A

hood 33 is positioned in front of the openings 31 and 3l. this hood being of generally tubular cross-section but flanged at the forward end to provide a large but relatively restricted opening 4Iy through which the llame passes. It will be noted that the burning gases passing through the opening 31 are directed centrally through the opening 4I. The small radial openings 3i, however, are directed to strike against the inside surface of the hood. 3l where the flame therefrom is caused to converge toward the center by reason of the flanged forward end of this hood. In this manner, relatively small portions of name or burning gases are directed inwardly against the main body of burning gas and keep the main body of gas ignited atl all times. The small flames at the openings or ports 3l are maintained' partly because the gas passing therethrough is restricted in velocity and partly because the hood 33 is maintained aba relatively higher temperature and assists in keeping the relatively smaller flames from being extinguished. Immediately in advance of the pilot burner, I provide a tubular vinsert 42 of heat resistingV material such as a high grade of alloy'steel. The burner itself may also be formed ofthe same or similar material. A housing 43 is provided around the entire burner 'structure equipped with a handle uA by means of which the housing can be moved to the right to clean or inspect the burner.

The principal control feature includes a pair of diaphragms, one operating to move air volume control mechanism and the other operating to control a supply of air to the rst mentioned diaphragm, this second mentioned diaphragm being controlled by the gas pressure within the manifold. I shall first describe the means for controlling the volume of air delivered to the apparatus.

The main air delivery pipe iii is provided with a specially designed elbow fitted with a rear boss 48, giving the elbow the appearance generally of a T. Within the boss 6B is supported an apertured plug Il in which a metering rod de is slidably secured. This sliding rod has a tapered portion 4l adapted to be extended into the forcing nozzle il to partially close the same. In advance of the tapered portion is a relatively small diameter extension El doweled on the center line of an apertured plate 52 carried betweenA the Venturi tube I2 and the casing Il. By forming the plug Il and the apertured plate 52 to close dimensions. the rod 43 and the tapered portion 49 thereof can be carried substantially exactly on the center line of the opening in the forcing nozzle il. I construct the rod I3 so that if the tapered portion 'thereof is extended entirely through the forcing nomic, a very small annular opening will re- 'Anastasia main for the passage of air therethrough. I have found that an opening of the order of a sixtyfourth to a'thirty-second of an inch gives very suitable results when the vaporizer. is of a 5 capacity to supply four or ilve burners. 'Ihis will permit all but one of the burners to be extinguished and a proper mixture still delivered to the remaining single burner; while the vaporizer will be of sufcient capacity to deliver a suitable como bustible mixture to the four or ilve burners when they are in full operation.

The rod is provided with a pivoted extension 52 pivoted to a leverarm l2 fulcrumed at 5I to a stationary extension I! supported by suitable 5 frame structure. A tension spring 51 connects the lower end of the lever arm 53 tending to hold the rod 4l at the extreme left or entirely out oi' the 'forcing nozzle passageway. Slightly below the pivot. the lever arm 53 is pivoted to a stud `5,8 D secured to a diaphragm 59. This diaphragm is supported within a bi-part diaphragm casing Il. It is obvious that if air under pressure is delivered 'to the diaphragm casing at the right side of the diaphragm looking at Fig. 1, and this air pressure 5 issumcient to overcome the force of the spring 51, the rod 48 will be forced to the right through the lever arm connections shown and the amount -of air passing through the forcing nozzle and consequently the amount of combustible mixture delivered to the burners will be decreased. I may place the manifold 2| directly in contact with the diaphragm I9 to secure direct control such as that which I show in Fig. 4 and which will afterward be described. In order to secure a more dei pendable operation, however, I employ a second 'diaphragm as an intermediate control, as will now be shown.

The intermediate control comprises a diaphragm 62 supported in a bi-part casing I3. One side of the diaphragm is in communication with the manifold through a pipe 64. At the opposite side of the diaphragm I provide a valve consisting of a valve seat 66 and a poppet type of valve S1 provided with a valve stem 88 slidably supported in the valve housing 8l of which the seat forms a part. A compression spring 1I- has one end bearing against the valve 81 and the opposite end bearing against one end of a cupshaped spring housing 12. This spring housing is threaded in the valve housing 89 so that the compression of the spring 1I can be controlled by the position of the spring housing. One side of the valve is connected by a pipe 1I to the main air pipe I O and the other side thereof is connected small bleeder passageway 16 is provided in the pipe 1I to permit return of the diaphragm when valve 81 is closed. j

For further control, an arm 11 is secured to the butterfly valve i6. This armisprovided withaplurality of openings for adjustably attaching thereto a rod 18 pivoted to the lever 53; This rod is shaped as shown to pass over the diaphragm casing Si without obstruction. A

In the operation of this mechanism, the vaporiaing chamber is rst heated up in any suitable way and then oil is admitted thereto at a level controlled by the oat mechanism il. 'I'he blower supplying air to the pipe is' now operated, 'and there will be some vapor drawn from the chamber i1, usually suilicient, to start the operation of the pilot burner. In lcold weather, or to secure rapid starting, it may be advisable to hold a blow torch at the pilot light opening ,by rst withdrawing the covering or shield 43.

by a pipe 14 to one side of the diaphragm i. A

During the time of starting,. it may be advisable to disconnect the rod 1l from the'arm 11 to allow the butterily valve I6 to be held completely open. When the pilot burner is iirst operated, it may also be necessary to hold the butterfly valve completely o pen. By these and other means the vaporizer is brought up to full operating condition and the combustible mixture produced thereby is delivered to the burners of the furnaces or ovens 29. Ihe spring 1l is set to the desired maximum requirements for the number of burners used so that when the maximum output of gas desired is being consumed, thevalve 61 will be held against its seat. Assume now that less than the entire number of burners is being operated. A slight pressure increase will result in the manifold and this will operate the diaphragm B2 and partially open the valve 01 against the action of spring 1l. This admits air from the pipe l0 to the right hand side oi.' diaphragm 59. Thisdiaphragm is then forced to the left, resulting in the rod 48 being moved slightly toward the right to partially close the opening of the forcing nozzle Il. At the same time, the arm 11 is moved to partially close the butterfly valve I6. This automatically decreases the amount of combustible mixture delivered to the manifold. If now another burner is lighted, the opposite eifect will take place and the amount of combustible mixture delivered to the manifold will be increased. It will be understood, of course, that this action takes place quickly and more or less constantly during the operation of a battery of furnaces or ovens. Usually the burners supplying heat' to such furnaces or other containers are thermostatically controlled. The control mechanism described co-operates and functions with automatic control of the burners and maintains substantially the exact amount of combustible mixture desired at any particular setting of the burners. By means of the present control, particularly with thermostatic control means for the burners, I have been able to maintain furnaces, ovens and other heating plants such as kilns and the like at a substantially uni-1 form pressure, varying not more than a few degrees either side of the desired setting under the most unfavorable conditions.

In connection with the equipment shown, it is at once apparent that all of the parts thereofare readily accessible for repair and/or replacement, and are simple and readily kept in order and adjustment. I find that it is desirable to clean'the metering rod 48 occasionally and to this end the lever arm 53 is bifurcated at the top and the rod extension is pinned between the bifurcations as shown particularly in Fig. 3. This permits removal of the pin and the direct withdrawal of the rod 48 without disturbing any other part of the mechanism or changing the adjustment thereof. l

Fig. 4 shows a rather simple modification of the principle shown in Fig. 1. The rod |48 is supported at only one point and is provided with a relatively long taper of the character shown. Other portions oi the equipment that are the same as shown in Fig. l are given the same reference characters prexed with the numeral 1 to facilitate and shorten the description. It will be noted that the pilot burner @24 is of somewhat modied construction with a hot point BI' for assisting in keeping the burner lighted. The hot .point 8l comprises a pair of wires which become heated by the pilot flame and thereby assist in keeping the pilot burner lighted.

` to diaphragm 82 in the manner shown.

A In this case I provide only a single diaphragm 82 in a diaphragm casing I8. A` single lever 84 is pivote intermediate its ends and is attacgteld e spring It? serves to hold the rod I to the left. IEhe pipe i communicates directly between the manifold and the diaphragm 82. When the pressure in t'ne manifold increases, the diaphragm is moved directly to the ieft as a result of auch increased pressure, and operates directly to move the rod lll. The reverse action takes place in the same manner. While the specic mechanism shown in Fig. 4 will operate satisfactorily under rnost conditions, I find that in general the control is somewhat more accurate when preerred form is used. On exceptionally large installations also employing large vaporizing units, I find that the pressure in the manifold is not suillcient as a rule to obtain o uick control response when the burners are turned oil' and on. For relatively small installations and particularly where a greater variation of temperature is permitted, the simplified form of Fig. 4 is thoroughly satisfactory.

In Fig. 5 I show still another modification adopted to be used principally when the vaporizing apparatus is operating the burners of only a single furnace or oven. 'Ihis modified apparatus however may be used in other ways. In Fig. 5 I also employ the same reference characters employed in the previous figures with the prefix "l" for indicating that a modification is shown. The particular portions of the previously shown apparatus of interest in the present connection are the diaphragm I 82, the lever arm IOL, the rod M8 which may be shaped substantially as shown in Fig. 4, andthe spring |51 tending to withdraw 'the rod from the forcing nozzle.

In the modification of Fig. 5 I use a thermostatic control directly. An expansible,` element 88, which may be in the -form ofa rod, is carried in a suitable position where it is aiIected directly by the heat resulting from burning the vapor-ized mixture. A suitable or usual position is within the oven which is being controlled. This expansible member carries a valve 31 which is adapted to engage a valve seat 88. One side of the valve seat body communicates with the atmosphere while the other side thereof communicates with a pipe 89 connected through a restricted passageway Si and a forcing nozzle 82 to the main air supply pipe ilu. This arrangement of the forcing nozzle 92 and the restricted passageway 9| creates a suction at this point and is connected by a pipe 93 to the diaphragm casing |83 and the diaphragm itz.

The operation ci this mechanism is as follows: The entire apparatus being set to the temperature desired. it will be assumed that the element 88 has been expanded to such a point that the valve 81 has engaged its seat 88 and prevented the passage of air therethrough. The air under pressure in pipe H0 will now cause a pressure to exist on the right hand side of the diaphragm i8! and this will operate the lever arm '|84 against the action of spring |51 and move the rod |48 in a direction to shut off the air and decrease the amount of gas or combustible mixture delivered to the burner of the furnace or ogen carrying the element 86. Assume new that this oven or furnace has its temperature lcwered.

The expansible member 86 will contract, the valve 81 will be removed from its seat and air is now permitted to pass therethrough. The result is that the air from the forcing nozzle 92 can now areasss' pass through the pipe 8l. It will create a suction of a character determined by the velocity through the restricted portion Il. 'Ihe air adjacent the diaphragm Il: being under pressure at this time and a partial suction belngcreated at pipe. the diaphragm will immediately return to normal and the rod III will be withdrawn.

' A feature of the operation of my invention is the provision ef simple means for raising or lowering an established manifold pressure to suit varying operating'requirements. For example. it mayb-eassumedthatinordinaryoperstioma four-inch manifold pressure is to be maintained. For starting a furnace cold, however, it may be advisable to raise the manifold pressure to force the furnace burner. The temion of spring 'il can then be increased by turning the adjustable 'housing 'I2 to the right. In this way, the manifold pressure may be increased to, say, ilve inches. Under other conditions. the vpressure of spring 1i cen be decreased and the manifold pressure lcan oe reduced to, say, three or three and onehalf inches. Some Iregulation can be made by controlling the tension of spring l1, out in general this adjustment is not so suitable, not so sstisfactory, and not readily controlled.

It will be understcod that the invention is not limited by the specific arrangement thereof shown nor by the detailed language employed in the description thereof, Nor is it limited in its use with the speelde type of vaporlzing mechanism shown. It may be used wherever a ccnstant manifold pressure is desired to be maintained and -gwherein a mixture of-air and vapor of uniform quality is desired under all operating conditions. v Moreover, the term "manifold as employed in the specification and particularly in the claims is used in a descriptive but not a restricted sense to include any portion of the passageway 'between the mixing nomic and the burner.

The invention is explained as applied te the situation where a plurality of separately controlled burners is provided. It may be used in any analogous or equivalent situation in which a variable demand is made on a vaporizing apparatus. A simple example is a single burner or group of burners variably controllw to regulate the temperature of an oven or furnace. In this connection. it is te lie/noted also that the invention can be applied in an installation.in which gas is substituted for a hydrocarbon vapor. The term vapor therefore is used in a broad sense.

What I claim as new and desire to protect by Letters Patent ofthe United States is:

1. In oil vaporizlng apparatus, oil vaporizing means, a manifcid, means for combining the oil vapor with air and delivering the resulting mixture to said manifold, means responsive to the pressure within the manifold for control'iing the amount of airand vapor mixture delivered thereto, said means including a diaphragm controlled mechanism actuated by air delivered by air supply mechanism, a valve for controlling the air delivered thereto, and a second diaphragm control mechanism, said second mentioned diaphragm control mechanism actuating said air controlling valve.

2. In oil vaporizing apparatus including an vaporizing chamber adapted to contain a supply of liquid oil, an inspirator including a forcing nozzle, means for delivering air to the forcing nozzle, a connection with the '-.faporlzing chamber and said inspirator at said forcing nozzle to draw vapor therefrom and mix the same with said air, a manifold for receiving said air and Vapor mixture and a plurality of burners connected with said manifold, separate means for burning a portion of said mixture and passing the hot gases resulting from the combustion of 5 said portion below the level Vof liquid in the vaporizing chamber, and means responsive to pressure of the mixture within the manifold for controlling the amount of air passing through said forcing Vnozzle without substantially affecting the l velocity thereof.

3. In oil burning apparatus, oil vaporizing means, means for delivering air under' pressure and mixing the same with vaporized oil, a manifold for delivering the mixture to a burner, a

l control mechanism for regulating the amount of air delivered, an air control diaphragm for operating said air control means, a second diaphragm controlled by pressure within said manifold, and a valvecontrolled by said second mentioned dia- 20 phragm for controlling the amount of air delivered against said first mentioned diaphragm.

4. In oil burning apparatus, an oil vaporizing chamber, an inspirator including a forcing nozzle connected to draw oil vapor from said chamber,

25 means for delivering air at relativelyhigh velocity to the forcing nozzle, a manifold receiving air and vapor mixture from the inspirator for delivery to a plurality of burners, and means responsive to pressure within said manifold for 30 controlling the amount of air delivered through the forcing nozzle without substantially affecting velocity thereof, said last mentioned means including area control means at the discharge end of the forcing nozzle.

35 5. In oil vaporizing apparatus, Aa vaporizing chamber, a manifold, an inspirator including a forcing nozzle and a mixing nozzle, a connection yto the vaporizing chamber between the forcing nozzle and mixing nozzle, means for forcing air under pressure to the forcing nozzle whereby vapor is mixed therewith to form a combustible mixture and delivered to the manifold, a metering rod having a tapered portion extending axially through the forcing nozzle, a diaphragm 45 one side thereof in communication with said manifold, a spring normally urging said metering rod in a direction to increase the pressure in the manifold, and means actuated by movement of the diaphragm in response to inn creased manifold pressure for moving said metering rod to decrease vthe area of said forcing nozlle and decrease said manifold pressure.

16'. In a device of the character described, an compressor and means for delivering air Il therefrom, a vaporizer, an inspirator including a forcing nozzle receiving said air under pressure and a connection tothe vaporizer whereby vapor is withdrawn therefrom and combined with said air. means for changing the cross sectional area l) of' the forcing nozzle, a diaphragm control for said last mentioned means including a diaphragm urgedby from said compressor in one direction and by a spring in the opposite direction, a Pilot valve for controlling delivery of air to the gli diaphragm, and means for opening and closing said pilot vvalve in response to the pressure of the and vapor mixture, whereby a substantially constant pressure is maintained between said inspirator and a delivery point for said mixture.

'lo 7. A device as denned in claim s, including bleeder means in communication with said diaphragm whereby to permit said spring to move t e diaphragm in the event of ysudden closing of said pilot valve.

il@ d. In a fuel :tm-1 device wherein preliminarily produced fuel vapors are mixed with air under pressure and delivered to a manifold for delivery to a plurality of burners, control apparatus comprising, means for 'regulating the amount of combustible mixture of fuel vapor 5 and air deliveredto the manifold, said means including means for regulating only the amount of fuel vapor delivered to the manifold, an air pressure operated device for actuating. both of said means, and means operated in response to the pressure within said manifold for causing operation of said air pressure operated device.

9. In a fuel burning device wherein preliminarily produced fuel vapors are mixed with air under pressureand delivered to a manifold for delivery to a plurality of burners, control apparatus comprising, means for regulating the amount of combustible mixture of fuel vapor and air delivered to the manifold, said means including means for regulating only the amount of fuel vapor delivered to the manifold, an air pressure operated device for actuating both of said means. and a valve for supplying air to said device, and means controlled by the pressure within said manifold for operating said valve.

l0. In a fuel burning device wherein preliminarily produced fuel vapors are mixed with air under pressure and delivered to a manifold' for delivery to a plurality of burners, control apparatus comprising, means for regulating the amount of combustible mixture of fuel vapor and air delivered to the manifold, said means including means for regulating only the amount of fuel vapor delivered to the manifold, an air pressure operated device for actuating both of said means, a valve for supplying air to said device. actuating means operable by the pressure within said manifold for operating said valve, and adjustable means forregulating the effective pressure required for operating said actuating means.

11. In oil burning apparatus, an oil Vaporizing chamber, means for vaporizing the oil, an

Ainspirator including a forcing nozzle connected to 'said vaporizing chamber, means for forcing air under pressure through said forcing nozzle whereby oil vapors are withdrawn from said vaporizing chamber, a manifold connected to said forcing nozzle and leading to a plurality of binners, and control means, responsive to the pressure within the manifold, for regulating the amount of air and oil vapor delivered to said manifold without substantially affecting the velocity of the air passing through the forcing nozzle, said control means comprising area control means at the discharge end of the forcing nozzle.

12. The apparatus described in claim 1l, including means for burning at least a portion of the mixture of air and oil vapors and utilizing the products of combustion thereof to vaporize 00 additional amounts of the oil in the vaporizing chamber.

13. In oil vaporizing apparatus. oil vaporizing means, a manifold, a forcing nozzle through which air is delivered to said manifold, means for combining the oil vapor with said air and delivering the resulting mixture to said manifold, and area control means at the discharge end of the forcing nozzle, said last mentioned means including means responsive to the pressure within the manifold whereby the amount of air and vapor mixture delivered to said manifold is controlled while maintaining the velocity of the air at the discharge end of the forcing nozzle substantially constant. 7d

van oil vaporizing chamber, an inspirator including a forcing nozzle positioned to draw vapor from said chamber, means for conducting air under pressure to said forcing nozzle, a manifold for delivering mixed air and vapor to a plurality of burners, and means for maintaining a substantially constant manifold pressure independently of the number of burners to which the mixture is being delivered, said last mentioned means including area control means at therdischarge end of the forcing nozzle, the area control means being operated in Vresponse to `pressure of the mixture within themanifold whereby the velocity of the air at the discharge end of the forcing nozzle is maintained substantially constant. Y A

15. In oil burning apparatus, an oil Vaporizing chamber, an inspirator including a forcing nozzle connected to draw oil vapor from said chamber, means for delivering -air at relatively high velocity to the forcing nozzle, a valve for controlling the amount of vapor delivered to the inspirator at any air velocity controlled in accordance with the rate of ow of the air delivered to the forcing nozzle, a manifold receiving air and vapor mixture from the inspirator for delivery to a pluralityof burners, area control means at the discharge end of the forcing nozzle for controlling the amount of air delivered to the forcing nozzle whereby the air velocity at the discharge end of the forcing nozzle is maintained substantially constant, and means respon-v sive to pressure within said manifold for operating said area control means. 16. The structure defined in claim 13, including separate means for maintaining a uniform mixture of the air and vapor.

17. The structure defined in claim 13, wherein the area control means comprises a rod disposed axially of the forcing nozzle and adapted to vary the area'of the outlet opening ofisaid forcing nozzle.

18. In oil vaporizing apparatus, a vaporizing chamber, amanifold, an inspirator including a forcing nozzle and a mixing nozzle, a connection to the vaporlzing chamber between the forcing nozzle and mixing nozzle, means for deliv- 5 ering air under pressure to the forcing nozzle and mixing it with fuel vapor in said mixing Ynozzle tol form a combustible mixture which is delivered to the manifold. a metering rod having a tapered portion extending axially through the 10 forcing nozzle, and means responsive to the demand for combustible mixture placed upon the manifold for moving said metering rod and maintaining a substantially constant pressure within *said manifold, the velocity of thealr through the l5 forcing nozzle being substantially'constant whereby inspirating action even at low air volume is maintained. y

19. In oil vaporizing apparatus, a vaporizing chamber, a manifold, an inspirator including a 20 forcing nozzlerand a mixing nozzle, a connection to the vaporizing chamber between Vthe forc-v ing nozzle and mixing nozzle, means for forcing air under pressure to the forcing nozzle and mixing it with fuel vapor in said mixing noz- 25 zle to form a combustible mixture which is delivered t) the manifold. a metering rod having a tapered portion extending axially through the forcing nozzle, means Vresponsive to the demand for combustible mixture placed upon the mani- I() fold for moving said metering rod and thereby maintaining a substantially constant pressure within said manifold, the'velocity of the air through the forcing nozzle being substantially constant whereby insplratlng action even at low 35 substantially uniform mixture is maintained even o at low volume.

` CLYDE B.