US2661055A - Film type liquid fuel burner - Google Patents

Description

Dec. 1,1953

Filed March 16, 1950 G. KOPP FILM TYPE LIQUID FUEL BURNER 3 Sheet's-Sheet 1 fa i Dec. 1, 1953 G. KOPP FILM TYPE LIQUID FUEL BURNER Filed March 16 1950 FIG 4.

I4 l6 /7 I8 19 3 SheetsSheet 2 Dec. 1, 1953 G. KOPP 2,661,055

FILM TYFE LIQUID FUEL BURNER Filed March 16, 1950 3 Sheets-Sheet s FIG 5.

Inventor ttorney Patented Dec. 1, 1953 UNITED STATES EPATENT OFFICE FILM TYPE LIQUID FUEL BURNER George Kopp, Rugby, England Application March 16, 1950, Serial No. 150,055

- more particularly to the combustion with the aid of a wickless burner of liquid fuels, such as kerosene, vapourizing oil, gas oil, fuel oil, crude oil, liquid tar or pitch and the like fuels of lower specific gravity than water, hereinafter for brevity referred to as oil.

The primary object of the present invention is to burn a film of oil with absolute safety and without back-firing by interposing a water layer between the burning oil and the oil supply duct or nozzle. The invention also aims to maintain a limited amount of oil in the burner which is such that the entire film of oil will be in a state of combustion, and also to regulate the thickness of the oil film according to the desired temperature or heat out-put.

Further objects are to ensure complete combustion by providing an adequate supply of air to the burning film of oil, and to avoid overheating of the layer of water upon which the oil fioats by creating a water fiow below the oil film,

The invention further aims to provide a burner of simple construction having no movable or mechanically operating parts and requiring no motive power for supplying the oil or air for combustion.

According to the present invention the method of liquid fuel combustion includes the steps of feeding oil upwards through a pool of water or other incombustible liquid to form a combustible film on the surface of the pool and distributing air over the surface of the oil film to support combustion thereof.

Preferably, during combustion of the oilfilm, the water in the pool subjacent the oil film is maintained at a constant level and a maximum temperature slightly below or equal to its boiling point by adding fresh water and by overflowing used water. This is achieved by continuously or intermittently introducing cold water into the burner at a rate sufiicient to make good any water losses due to evaporation and allowing the water, which is already heated up, to overflow to waste. This also enables the liquid level in the burner to be maintained constant not only with respect to the burner casing but also to the positions at which air is supplied for combustion purposes.

Again, the air for supporting combustion is fractionally distributed over the entire surface of the oil film by being fed in separate streams upwards through, but in isolation from, the water pool and oil film.

The liquid fuel burner of the present invention 5 Claims. (c1. 158-93) comprises a tray, or other vessel, means for maintaining therein a film of oil of predetermined thickness upon a subjacent pool of water and means for supplying air for combustion substantially over the entire superficial area of said oil The burner is conveniently provided with oil and water inlet ducts in the lower part of the vessel, and a plurality of air supply tubes extend upwards through the water and through the film of oil floating therein, said tubes being open below the vessel and opening above the oil film, and being arranged to distribute the air to the entire surface of the oil.

Circulation of the water in the pool is attained by the provision of one or more baffles or partitions which separate the burner tray or like vessel into a burner chamber and an adjacent overflow chamber, which communicate with each other below the oil and water interface over the upper edge of a weir, so that the water supplied either continuously or intermittently to the pool of water in the burner chamber overflows below the oil and water interface intothe overflow chamber, from whence it may be discharged through an overflow pipe.

The air inlet tubes may be vertically arranged and project above the burning film of oil so that their upper ends are heated by the fiame and partially heat the air for combustion.

The oil supply to the burner may be effected i through one or more oil ducts and these oil ducts may be provided in the bottom of the burner tray and open into the tray through one or more orifices in the oil ducts.

invention- I Inthese drawings:

Figure l is a sectional elevation on the line |l I of Figure 2, whichis a plan view of the burner,

Figure 3 is a detail sectional view substantially on the line III-III of Figure 2,

Figure 4 is a plan view of a modification showing control means for the oil and water supplies, and

Figure 5 is a sectional view through a conven- -ient form of safety device for the oil and water supplies-to the burner.

Figures -1-3 of the drawings illustrate a tray or open vessel 4 supported on a hollow base formed by parallel'side walls 5 and an end wall 6, leaving the base' open at the other end for the admission of air. Securedin the bottom wall 1 of the vessel 4 is a plurality of uniformly distributed vertical air tubes 8 having open ends, the height of the hollow base being such that its frontal opening, through which air enters, corresponds to the total of the passage areas of the air tubes which in turn depends on the size and output of the burner. At one end of the vessel 4 is a water inlet connection 3 which communicates with a longitudinal passage l drilled or cored in the bottom. wall 1. Similarly, an oil inlet connection ll communicates with an oil passage l2 drilled or cored in the bottom wall 1.

Orifices [3 are drilled or cored vertically downwards in the bottom wall 1 into the water passage H) at a position remote from the connection 9. Similar orifices l2a are drilled in the bottom wall into the oil passage 12,. but these preferably are uniformly distributed along the length of the oil passage I2. It will be appreciated that a plurality of oil passages similar to the passage I2 may be employed, according to the size of the burner.

A partition 14 is provided at one end of the vessel 4, remote from the side at which the water inlet connection 9 is located, said partition 14 being of such height that it forms a weir over which water supplied to the vessel flows when it reaches the level of the upper edge of the partition. Spaced from the partition [4 and extending downwards into a well I5 is a baiile l6 whichseparates the vessel from an overflow chamber l1 fitted in its lower part with an outlet funnel l8 which communicates with a drain outlet connection l 9. It will be appreciated that the weir l4 serves to prevent cold water short-circuiting directly to the overflow chamber ll whilst the battle it serves to prevent the oil film from reaching said overflow chamber and running out to waste.

The operation of the improved burner is as follows: Water is supplied to the vessel 4 through the water inlet connection 9, longitudinal water passage 40 and orifices [3 until the water flows over the weir l4 and out of the overflow cham- The oil which is.

her I! through the funnel [8. preferably supplied by gravity from a reservoir 1 or tank which may be fitted with a constant ,level regulator to ensure delivery of the oil under a. constant head, is fed to the vessel 4 through the oil inlet connection ll, longitudinal oil passage l2 and orifices [2a and floats by virtue of its lower specific gravity to the surface of the water pool in the vessel 4, where it may be ignited and burns as a film of oil. Air for combustion entering below the bottom I of the vessel 4 passes up by thermosiphonic action through the air tubes 8, which open slightly above the level of the film of oil. It will be appreciated in this manner the air/fuel ratio is automatically maintained substantially constant over a wide range of combustion rates.

As combustion proceeds, the temperature of the water subjacent to the burning oil rises, andby continuously or intermittently introducing cold water into the pool the temperature is maintained at, or slightly below, boiling point and evaporation losses are made good. It is preferred to introduce a slight excess of water to ensure that this purpose is achieved, as all excess is allowed to overflow. Further the temperature of the oil rising through the hot water pool to reach the surface thereof increases and its viscosity decreases, thus improving the formation of a continuous film and its combustion.

In the construction according to Figure 4 in which is illustrated a burner of greater capacity than that of Figures 1-3, the water feed to a vessel 2%, having twenty-eight air tubes 8 in each of a number of rows distributed uniformly over the area of the vessel, is from a source of supply through a throttle valve 2 I a stop valve 22, safety device 23 and conduit 24, leading to an inlet for the burner which corresponds to the inlet 9 of the construction according to Figure 1.

The oil feed is from a source of oil supply, not shown, through a manually adjustable valve 25 for controlling oil flow in accordance with changes in temperature or pressure, and thence through the safety device 23 and an outlet 26 therefrom which leads to a plurality of distributor inlets 28, in place of the single inlet ii of Figure 1. The safety device 23 is also in communication with the burner through a duct 2? leading to the burner at 29.

The outlet drain connection for water leads to waste through a drip chamber or overflow sight 30.

The safety device 23 is illustrated at Figure 5 and comprises a casing containing a float 3! from the roof 3 la of which a pair of valve spindles 32, 33 are suspended. The spindle 32 has a valve formed of a pair of opposed cones 34, 35, in the upper cone 34 of which is a peripheral groove 36 which extends from one end to the other of the cone and constitutes a passage of narrow section which is always available for oil flow at an idling rate. The spindles and their valves are vertically displaceable relatively to chambers 31, 38 respectively in accordance with float displacement, and the lower ends of said chambers are shaped complementarily to the valve heads. An inlet for oil from a source of oil supply such as a tank is shown at 39 whilst an inlet for water is shown at 89 below a conical head 4! at the lower end of the spindle 33.

It will be appreciated that the provision of two Valves 34, 35 on the spindle 32, as compared with one valve 4! on the spindle 33, tends to unbalance the suspension as a whole from the roof am of the float. This difiiculty, however, is avoided by cutting away the head 42 of the valve spindle at 43 to such an extent that the loss of weight is equal to the weight arising from the additional valve at the base of the spindle with the result that the total weight of the spindle 32 and the elements associated with it is equal to that of the spindle 33 and its elements.

The safety device is mounted upon a stand l l the height of which varies in accordance with the capacity of the burner, that is to say the height of the stand 44 is increased as the height of the hollow base under the burner increases with the capacity of the burner in order to cooperate with higher liquid levels in the latter.

'Inoperation should obstruction or cessation of the water supply to the burner arise, the supply level would be lowered and this, by virtue of the duct 2i between the float chamber of the safety device and the burner at 29, would be aocompanied by consequential descent of the float 3i and the valve spindles 32, 33 in the safety device, thereby cutting off the supply of fuel to the burner except through the pilot or idling groove 36 which cannot feed more than approximately 4% of the maximum supply of fuel. In the event of a stoppage of the overflow from the burner, the level in the safety device will rise thereby causing the fioat 3! to rise and with it the valve spindles 32, 33 with the result that both the oil and water supply are cut off.

The air supply to the burner may be regulated conveniently by providing a reciprocatory or rotary slide valve for controlling the inlet ends of the air supply tubes 8.

The burner of the present invention ensures that only that amount of oil is present in the burner chamber, which, by contact with air, is in a state of combustion, a constant fiow of oil being introduced below the water level, and the oil rising to the surface of the pool by virtue of its specific gravity being lower than that of water.

The water may be replaced by any other suitable liquid of an incombustible nature having a ture of the air entering the combustion chamber,

and creates a draught in the air tubes by thermosyphonic action. The extent to which the air tubes project above the oil film may thus be used to determine the volume and temperature of the air supplied to the fiames in order to ensure complete combustion. The number, size, and distribution of the air tubes should be such as to provide the requisite quantity of air for complete combustion of the oil.

The maximum thickness of the oil film should not exceed that for which the cooling effect of the water pool is sufficient to prevent premature distillation of the lighter fractions of the oil under combustion.

In order to light the burner it may be primed with methylated spirts or the like to establish a burning film of spirit prior to the admission of the oil for combustion, which will ignite by contact with the burning spirit. Alternatively a torch may be introduced into the burner to ignite the oil film.

The oil supply may be regulated by a manually operated valve, by a mechanically operating thermostatic device or again by means of a thermal electric switch in order to adjust the heat of the burner to demands.

It will be understood that the burner chamber or vessel 4 may be of any convenient shape with provision for the admission of air to the underside thereof and that the oil and water 1. A liquid fuel burner comprising a vessel in the form of a tray having a water inlet, means for supplying cold water through said inlet to provide a pool of water in the tray, means for supplying oil to said tray to form a film fioating on said pool of water, means for supplying air for combustion substantially over the entire exposed area of said film of oil, a baflle in said tray remote from the water inlet for dividing the tray into combustion and overflow chambers, and a weir located adjacent to said bafile, said weir and said baffle being arranged for fiow of excess water from said pool over said weir and under said baflle to said overflow chamber, and means for discharging said excess Water from the overfiow chamber.

2. A burner as defined in claim 1 including a safety device for substantially cutting off the fuel supply to the burner upon failure of the water supply to the burner and for completely cutting off both the oil and water supplies to the burner upon stoppage of overflow of water from the burner.

3. The combination, with a burner of the kind in which a film of liquid fuel to be burned is floated on a body of heavier liquid, of means for feeding fuel to the burner, mean for feeding said heavier liquid to the burner, and a, safety device forming a part of said feeding means, said device comprising a float movable in response to fluctuations in the level of said heavier liquid in the burner, a first control valve for control ling the fuel supply and a second control valve for controlling the supply of said heavier liquid, said control valves being actuated in response to movement of said float, said first control valve being moved to a first position substantially cutting off the supply of fuel upon downward movement of the float in response to a lowering of the level of said heavier liquid in the burner.

4. Apparatus as defined in claim 3, in which said first control valve is provided with a bypass passage permitting fiow of a pilot quantity of fuel to the burner when said valve is in said first position.

5. Apparatu as defined in claim 3, in which said first control valve is moved to a second and fully closed position and said second control valve is moved to fully closed position when said fioat rises in response to rise of the level of said heavier liquid from it normal level in the burner.

GEORGE KOPP.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 86,024 May at al. Jan. 19, 1869 101,964 Truesdell Apr. 12, 1870 168,782 Rice Oct. 11, 1875 370,883 Moore Oct. 4, 1887 409,576 Gray Aug. 20, 1889 600,409 Damon Mar. 8, 1898 FOREIGN PATENTS Number Country Date 1,380 Great Britain of 1875

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