US2267451A - Adjustable oil burner - Google Patents

Description

Dec. 23, 1941. K. K. H. EWERYD ETAL ADJUSTABLE OIL BURNER Filed Oct. 5, 1959 2 Sheets-Sheet 1 v z l mm INVENTORJ ATTO NY Dec. 23, 1941. K. K. H. 'EWERYD ETII'AL ADJUSTABLE OIL BURNER 2 Sheets-Sheet 2 Filed Oct. 5, 1939 J M ATTORNEY Patente(l Dec. 23, 1941 UNITED STATE ADJUSTABLE OIL-BURNER Knut Karl Herman Eweryd and Tor Axel fidman, Karlskrona, and Lars Axel Widlng, Stockholm, Sweden, assignors to Aktiebolaget Giitaverken, Gothenburg, Sweden, a corporation of Sweden Application October 5, 1939, Serial No. 298,062

g In Sweden October 6, 1938 8 Claims. (Cl. 158-73) This invention relates to improvements in adjustable oil burners for boilers, hot water heaters or other heating plants.

The conventional oil burners, which are at present available, cannot be manufactured for lower oil capacity than about 2' kilogrammes of oil per hour. This is due to the practical impossibility of producing oil burner nozzles with oriiices for smaller oil delivery than 2 kilogrammes per hour at the lowest practical oil pressure,

which will maintain atomization of the oil. Considering, for instance, an oil with a heating value of 10,000 kilogramme calories per kilogramme of oil, the quantity of heat whichis liberated by the combustion of the oil delivered by an oil burner of the above mentioned conventional type, is at least 20,000 kilogramm calories per hour, and consequently, the necessary heat exchange surface in an ordinary water heating apparatus is at least two square meters, if economical heat exchange is to be obtained.

When such an oil burner is provided in a small heating plant, the heat exchange surface is usually insufficient and the combustion chamber too small for said oil quantity. This results in heat losses and a considerable amount of unburned products in the combustion gases. Since the maximum heat consumption per hour in a small heating plant is often much less than the smallcording to the invention with a spraying nozzle with variable spraying angle and adjacent to the path of the oil jet delivered by said nozzle there is located means for catching a portion of said oil jet, so arranged that the oil, which passes the catching means, is fed to the combustion zone of the burner whereas the oil which is caught by the catching means is conducted away without entering the combustion zone.

With an oil burner of this type it is possible to control the oil quantity supplied to the combus tion zone according to the momentary variations of the heatconsumption of the heating apparatus automatically or manually within very wide For instance, a burner nozzle, which atlimits.

011 per hour, may easily be adjusted so that the peripheral parts of the oil jet are retained by the catching means and the oil quantity supplied to the combustion zone is reduced to 10 per cent of the total capacity of thenozzle, that is to 0.5 kilogramme of oil per hour. In such a case the combustion zone is supplied with 5,000 kilogramme calories per hour and it is then possible, for instance, to operate a heating apparatu with less than one square meter-heat exchange surface continuously without undue losses in the combustion gases.

A further object of the invention is to combine the adjustable spraying nozzle with an adjustable oil catching means in order to increase still further the range within which the oil burner may be operated. Further features of the invention are set forth in the following specification and claims.

In the accompanying drawings some embodiments of the invention are illustratedby way of example.

' Fig. 1 is a vertical section of a heating plant provided with an oil burner according to the invention.

Fig. 2 is a longitudinal section of an oil burner a larger scale.

Fig. 3 is a section on lin III-III in Fig. 2.

Figs. 4 and 5 are longitudinal sections of two further embodiments of oil burners according to the invention.

Fig. 6 is a longitudinal section of an adjustable spraying nozzle for an oil burner according to the invention.

Fig. 7 is a detail of a control device for said nozzle.

Fig. 8 is a section on line VIII-VIII in Fig. 6.

Fig. 9 is a longitudinal section of an adjustable spraying nozzle according to a further embodiment of the invention; and I Fig. 10 is a cross-sectional view taken on the line X-X of Fig. 5.

Fig. 1 shows a plant comprising a heating apto the invention. The heating apparatus, which may naturally be of any design, comprises a combustion chamber 2, heat exchange portions 3 and a combustion gas outlet 4. Thermostatic control devices 5 and 6 are provided with their heat sensitive members 1 and 8, respectively, extending into the combustion gas outlet 4 and the hot water jacket of the heating apparatus I. A fuel oil tank 9 is connected by means of normal oil pressure deliver five kilogrammes of a conduit l0 to an oil pump ll of conventionm design driven by an electric motor II, which also drives a fan or blower l3 for the combustion air. The device may be a switch adapted to interr'upt the circuit of the motor when the gas temperature in the outlet 4 falls below a certain value. The oil pump, the motor and the fan are mounted on a tubular shaft i4 journalled in a casing I5 carried by a support l6. If a sufficient natural draught is available the fan may be omitted. The oil burner comprises a burner housing II, which forms the front end of the casing l5 and is secured in an opening i8 in the heating apparatus l. The burner housing I! contains an adjustable spraying nozzle l 9, which, through a tubular stem 29 extending through the shaft i4, is connected with a device 2i for controlling the spraying angle of the nozzle, which device is described in detail in connection with Figs. 6 and 7. The control device 2| is actuated by the thermostat 6 through a flexible cable 22 such as a Bowden cable, and increases the spraying angle of the nozzle when the water temperature rises and vice versa. A spray oil catching means 23 in the shape of a drum surrounds the nozzle l9, and more or less of the oil delivered by the nozzle is caught by said means as the spraying angle is increased or reduced. A housing 24 serves to gather superfluous oil. A conduit 25 leads oil from the oil pump I I to the control device 2|, which is connected with the nozzle, and another conduit 26 is provided for leading superfluous oil from the housing 24 back to the oil tank 9.

The oil burners illustrated in Figs. 2, 4 and 5 may replace the burner indicated in Fig, 1, and

may in similar manner be built together with casings containing an oil pump, a fan. and a motor, but they may also be incorporated in any other known type of oil burner assembly.

The burner according to Figs. 2 and 3 comprises a burner housing 21, which may be secured to a wall of a combustion chamber of a heating apparatus by means of a flange 28 in the same manner as illustrated in Fig. 1. The housing 2'! serves to lead combustion air to the combustion chamber. A nozzle 29 with-an adjustable spraying angle is provided within the drum-shaped nozzle housing 30 intl'le burner housing 21. 3| is a stem, which contains fuel supply conduits and connects the nozzle with a spraying angle control device as will be hereinafter described in connection. with Figs. 6 and 'Z. The nozzle housing 30 is provided with openings 32 serving to prevent pressure reductions within the nozzle housing during the operation of the nozzle and to admit air to the jet immediately and which is connected with the burner housing 21 and the drum 33 by means of plates 38 and 39, respectively, Fig. 3, which, if desired, may be adapted to produce a whirling motion of the air flowing to the combustion chamberthrough the burner housing 21 around the nozzle housing 38. When the spraying angle of the nozzle 29 is adjusted to a value near the taper angle of the drum 33, all oil delivered by the nozzle flows into the combustion chamber through'the open end of the burner housing 21. However, as the spraying angle of the nozzle is increased, more and more of the peripheral portions of the oil jet 34 is deposited on the inner surface of the drum 33 and moved towards the groove 35 and conducted back to the oil tank and thus withdrawn from the combustion process in the heating apparatus. If the pressure of the oil supplied to the nozzle 29 is substantially constant,

the amount of oil delivered by the nozzle will be substantially constant independently of the momentary spraying angle, and, consequently, the amount of oil supplied to the combustion chamber varies substantially in inverse ratio to the size of the spraying angle.

In the embodiment according to Fig. 4 a burner housing 40 is provided with a flange 4i for securing the burner to a heating apparatus such as I in Fig. 1. Oil under pressure is admitted through a hollow stem 42 to a nozzle 43, the spraying angle of which may be adjusted automatically or manually by means of a rod 44 extending through the stem 42, as will be described in'detail in connection with Fig. 9. The angle of the oil jet 45 delivered by said nozzle may be varied over a wide range but the amount of fuel delivered by the nozzle at a certain oil pressure is substantially constant irrespective of the prevailing spraying in front of the nozzle in the nozzle housing.

angle. The spraying nozzle 43 is disposed in a nozzle housing 46, which is provided with air inlet openings 41, through which air is admitted to the interior of the nozzle housing 46. The housing 46 is provided with a front wall 43 forming an oil catching means and having an opening 49. The amount of oil supplied to the heating apparatus depends upon the relation between the area of the opening 49 and the total cross-sectional area of the oil jet in the plane of said opening. Consequently, the amount of oil supplied to the heating apparatus depends directly upon the spraying angle of the jet and may be varied from a maximum value, when all oil delivered by the nozzle is injected into the heating apparatus and the spraying angle is so small that all of the oil jet passes through the opening 49, to a very low value corresponding to the largest obtainable jet angle. The oil particles deposited on the inner surface of the wall 48 and the nozzle housing 46 flow to the bottom 29, as illustrated in Fig. 2, but said drum may naturally be of cylindrical or other suitable shape. "At the large open end of the drum 33 a peripheral collecting groove 35 is formed for collecting.

directs a portion of the air towards the oil jet of the nozzlehousing and escape through an opening 59 to a collecting chamber 5!, from which a drain pipe 52 leads the oil back to the oil tank or the pump, respectively. An external wall or shield 53 is provided in front of the wall 48 and has an opening 54 corresponding to the opening 49. A space 55 is formed between the shield 53 and the wall 48, in which space oil deposited on the edges of the opening 49. is gathered and from which said oil is conducted to the chamber 5|. A deflecting plate 56 and guide vanes 51 and 58 are provided in the space between the nozzle housing 46 and the drum-shaped burner housing 40, said plate and vanes serving to direct the air into close contact with the oil jet so as to produce a perfect mixture.

In the embodiment illustrated in Figs. and an adjustable spraying nozzle 59 is provided in a nozzle housing 60 disposed in a burner housing 6| provided with an external flange 62 for securing the burner to a heating apparatus such as the apparatus illustrated in Fig. 1. The nozzle housing 60 is provided with air inlet openings 63 and an oil outlet opening 64 in a lower portion of the housing communicating through a drain pipe 65 with the oil tank. Oil under pressure is admitted to the nozzle through a hollow stem 66, which may be connected to a control device such as 2| in Fig. 1, and a jet 6! with variable spraying angle is delivered by the nozzle. At a suitable distance in front of the nozzle a catching means in the form of an iris diaphragm 68 is provided, which may be operated automatically or manually by means of a rotatable shaft 69 and a gear wheel I0 co-operating with the diaphragm. Only the oil particles which pass through the opening II of the diaphragm 68 are injected into the combustion chamber of the heating apparatus, whereas the other particles of the jet are deposited on the diaphragm 68 and flow down into the lower portion of the nozzle housing 60 and through the opening 64 and the pipe 65 back to the oil tank. A second diaphragm or cover I2 is provided outside the iris diaphragm 68 and Figs. 6 and 9 illustrate two different embodiments of spraying nozzles with adjustable spraying angle, which may be used in connection with the oil burners according to the invention, but

other adjustable nozzles of known constructions may also be employed in connection with the invention.

In the spraying nozzle according to Fig. 6, which is employed in the oil burners illustrated in Figs. 1, 2 and 5, fuel oil under pressure is supplied to a distribution chamber 18 in a body 2|, Figs. 1 and 6, from which the oil flows through a pipe 19 and a duct 80 to .a central chamber III in the nozzle body 82. From the chamber 8I the oil flows through a duct 83 to a centrally disposed circular chamber 84 formed by two bodies 85 and 86, which are held in place by means of a collar 81 screw-threaded onto the nozzle body. The body 85 is provided with an eccentric bore 88 communicating with the chamber 84 through a slot 89, Fig. 8, directed tangentially towards the circular chamber 84. The bore 88 is connected through a duct 90 and a pipe 9| with the chamber I8. The supply of pressure oil to the pipes I9 and 9I is controlled by two plungers 92 and 93 operated by means of a cross piece 94, a lever 95 and a rod 96. The cross piece 94 is journalled on a pivot 9'! and the plungers 92, 93 are movable in bores 98 and 99 in the body 2| so that the same oil quantity is always admitted to the nozzle and so that the oil quantity flowing through the duct 83 relatively to the oil quantity flowing through the duct 89 varies according to the position taken by the cross piece 94, which depends upon the water temperature in the heating apparatus. For this purpose the thermostatic control device 6, 8, Figs. 1 and '7, contains a rod II3 with a different coefficient of elongation than the tube 8, which actuates the flexible cable 22 and the rod 96 against the action of a spring I I4, Fig. 6. The oil is delivered by the nozzle through the orifice I 00, and it all the oil delivered by said orifice comes through the central duct 83, that is it the plunger 93 has closed the bore 99, the spraying angle of the jet is a minimum and the burner injects the maximum oil quantity into the heating apparatus. If, on the contrary, all the oil delivered by the nozzle flows to the chamber 84 throughthe tangential. duct 89 only, that is if the plunger 92 has closed the bore 98, the oil in the chamber 84 is caused to rotate rapidly and the maximum spraying angle is obtained, which may be some 160. A variation of the relation between the oil quantities supplied through the ducts 83 and 89 results in a perfectly continuous variation of the spraying angle of the nozzle. The lever may naturally be operated manually instead of automatically and the illustrated control valve mechanism may be replaced by a three way cock or separately operated valves for the difierent oil conduits.

In the embodiment illustrated in Fig. 9 and employed in the burner according to Fig. 4 the nozzle body IN is provided with a fuel supply pipe I02 connected through a duct I03 with an annular chamber I04. A valve I05, which is screw-threaded at I06 in the nozzle body IN, is rotatable by means of a rod I01 corresponding to 44 in Fig. 4 to and from a conical seat formed by a body I08, which is secured at the end of the nozzle body IN by means of a collar I09 screwthreaded'onto the nozzle body. 'Ihe body I08 is providedwith an orifice H0 and a central circular chamber III is formed in the valve and between the end of the valve and the conical valve seat formed by the body I08. The valve is provided with a duct IIZ leading tangentially from the annular chamber I04 to the chamber III. When the valve I05 is in its foremost position, as illustrated in Fig. 9, all oil delivered by the orifice passes through the duct H2 and, consequently, maximum rotation of the oil in the chamber III and maximum spraying angle is obtained. In every other position of the valve I05, the oil also flows radially to the chamber III through the space between the conical valve and the valve seat formed by the body I08 so that less rotation is produced in the chamber III. Consequently, the position of the valve directly determines the relation between the oil quantities flowing tangentially and radially to the chamber III and thereby the spraying angle of the nozzle. The spraying nozzle according to Fig. 9 also permits a completely continuous variation of the spraying angle of the oil jet delivered by the nozzle and, consequently, also of the fuel oil quantity injected into the combustion chamber. The rod I0'I may be connected to a thermostatic control device at the heating apparatus or it may be adjusted manually by means of a suitable hand wheel or the like provided on the rod.

When the spraying angle of the nozzles above described is varied, the oil density of the jets is also varied but the degree of atomization is substantially the same forv diiierent sprayingangles, and, consequently, a satisfactory combustion is always obtained, which is not always the case when the oil quantity delivered to the combustion zone is controlled by variation of the pressure of the oil supplied to the nozzle.

The embodiments of the invention above" described and illustrated in the drawings should only be considered as examples and the invention may naturally be modified in several dlflerent ways within the scope of the following claims.

What we claim is:

1. In an oil burner, a spraying nozzle with variable spraying angle for atomizing fuel oil supplied to said nozzle, and an oil catching means disposed adjacent to the path of an oil jet delivered by the nozzle and adapted to catch portions of said oil jet and to prevent caught oil from entering the combustion zone of the burner.

2. In an oil burner, a spraying nozzle having a central circular chamber provided with a central discharge orifice, a duct leading to a centrally disposed portion of said chamber, a second duct leading to said chamber and directed tangentially to the chamber, a distribution valve mechanism controlling the oil supply to said ducts so arranged that an increasing of the oil supply to one duct is accompanied by a decreasing of the oil supply to the other duct and vice versa, and an oil catching means disposed adjacent to the path of an oil jet delivered by the nozzle and adapted to catch portions of said oil jet and to prevent caught oil from entering the combustion zone of the burner.

3. In an oil burner, a spraying nozzle having a central circular chamber provided with a central discharge orifice, a duct leading to a centrally disposed portion of said chamber, a second duct leading to said chamber and directed tangentially to the chamber, a valve controlling the oil supply to said first-mentioned duct, a valve controlling the oil supply to said second duct, a member connecting said valves and adapted upon displacement in one direction to increase the valve opening of the first-mentioned valve and to reduce the valve opening of the second valve and upon displacement in the opposite direction to cause contradictory movements of the valves, and an oil catching means disposed adjacent to the path of an oil jet delivered by the nozzle and adapted to catch portions of said oil jet and to prevent caught oil from entering the combustion zone of the burner.

4. In an oil burner, a spraying nozzle with variable spraying angle for atomizing fuel oil supplied to said nozzle, and an adjustable oil catching means disposed adjacent to the path of an oil jet delivered by the nozzle and adapted according to the adjustment of said catching means to catch more or less of said oil jet and to prevent caught oil from entering th combustion zone of the burner.

5. In an oil burner, a spraying nozzle with variable spraying angle for atomizing fuel oil supplied to said nozzle, an oil catching means disposed adjacent to the path of an oil jet delivered by the nozzle and adapted to catch portions of said oil jet and to prevent caught oil from entering the combustion zone of the burner, and means providing an adjustable opening in said catching means for admitting at will a desired portion of the oil jet into the combustion zone of the burner.

6. In an oil burner, a spraying nozzle with variable spraying angle for atomizing fuel oil supplied to said nozzle, an iris diaphragm disposed in the path of an oil jetdelivered by the nozzle and adapted to catch more or less of said oil jet according to the momentary adjustment of said diaphragm and to prevent oil caught by the diaphragm from entering the combustion zone of the burner, and means for varying th opening of the iris diaphragm.

'7. In an oil burner, a spraying nozzle with variable spraying angle for atomizing fuel oil supplied to said nozzle, a means for controlling said spraying angle of the nozzle, a temperature sensitive device provided in heat exchange relation with medium heated by the burner and adapted to actuate said controlling means according to the temperature of said medium, and an oil catching means disposed adjacent to the path of an oil jet delivered by the nozzle and adapted to catch portions of said oil jet and to prevent oil caught by said catching means from entering the combustion zone of the burner.

8. In an oil burner, a spraying nozzle with variable spraying angle for atomizing fuel oil supplied to said nozzle, a housing surrounding said nozzle, and a portion of said housing remote from the nozzle forming an oil catching means disposed adjacent the path of an oil jet delivered by the nozzle and adapted to catch portions of said oil jet and to prevent caught oil from entering the combustion zone of the burner.

KNUT KARL HERMAN EWERYD. TOR AXEL 6DMAN. LARS AXEL WIDING.

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