US20060147855A1 - Liquid fuel supply unit for a liquid fuel burner and a liquid fuel burner system - Google Patents
Liquid fuel supply unit for a liquid fuel burner and a liquid fuel burner system Download PDFInfo
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- US20060147855A1 US20060147855A1 US10/533,142 US53314203A US2006147855A1 US 20060147855 A1 US20060147855 A1 US 20060147855A1 US 53314203 A US53314203 A US 53314203A US 2006147855 A1 US2006147855 A1 US 2006147855A1
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- United States
- Prior art keywords
- liquid fuel
- supply unit
- compressor
- feed pump
- burner
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K5/00—Feeding or distributing other fuel to combustion apparatus
- F23K5/02—Liquid fuel
- F23K5/14—Details thereof
- F23K5/142—Fuel pumps
- F23K5/145—Fuel pumps combined with fans
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K5/00—Feeding or distributing other fuel to combustion apparatus
- F23K5/02—Liquid fuel
- F23K5/04—Feeding or distributing systems using pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K2300/00—Pretreatment and supply of liquid fuel
- F23K2300/20—Supply line arrangements
- F23K2300/201—Pumps
Definitions
- the present invention relates to a liquid fuel supply unit for a liquid fuel burner and a liquid fuel burner system. Especially the invention relates to domestic heating the liquid fuel burner having a heat output of less than 10 kW.
- Liquid fuel burners such as oil burners
- oil burners are quite common for domestic use.
- Ordinarily such oil burners are of the oil pressure atomizing type having high-pressure pumps delivering oil at high pressure.
- These burners operate on the principle that when oil under pressure is permitted to expand through a small orifice, it tends to break into a spray of very fine droplets, which are suitable for combustion.
- These burners are usually designed to operate with oil pressure as high as 3 MPa and viscosities of from 2 cSt.
- the principle upon which these burners operate requires that the pressure drop across the orifice be maintained high and as nearly constant as possible in order to achieve the necessary fine atomized droplets and also to avoid pulsating combustion.
- the minimum output of the burner is controlled by the size of the holes in the orifice.
- the smallest feasible holes are 0.1 mm in diameter, as smaller holes will clog very quickly due to inevitable particles in the oil or due to soot build-up from the combustion, increasing the need for maintenance to an intolerable level.
- the ordinary minimum output of oil burners having an orifice with the smallest holes possible is about 10 kW, which exceeds the static demand of an ordinary household.
- U.S. Pat. No. 5,692,680 discloses a fuel supply unit for an oil burner.
- This fuel supply unit comprises a pump delivering pressurized fuel to a metering orifice, where the flow rate of fuel delivered can be regulated by regulating the pressure differential to maintain a constant flow independently of the elevation of the burner and the elevation of the tank with respect to the pumping unit.
- this kind of supply unit is not desirable.
- EP-A-0 556 694 discloses a burner system for liquid fuel and provided for easy modulation to compensate for changes in fuel viscosity.
- the burner system thus comprises a gas atomizing nozzle fed by an air compressor and a fuel pump, the fuel being fed through a regulator regulating on basis of a pressure difference.
- U.S. Pat. No. 4,391,580 discloses a system for supplying fuel to a pressure atomization fuel oil burner nozzle comprising a rotating gear pump with a rotatable valving structure for delivering fuel at pressure pulses and at a rate depending on the rotational speed of the pump, the rate thus being controllable.
- the system further comprises a blower driven by the same motor as the pump.
- EP-A-0 013 488 discloses a unit comprising a fuel oil pump, a fan and a motor mounted on a common shaft and an electric circuit for controlling the unit.
- the object of the present invention is to provide a liquid fuel burner system which when applied to a boiler of a domestic heating system allows substantially continuous, modulate operation at least during the heating season.
- a further object is to provide a unit for use in such a system.
- a liquid fuel supply unit for a liquid fuel burner with a gas atomizing nozzle comprising a liquid fuel feed pump and a compressor, said liquid fuel feed pump having an inlet connectable to a liquid fuel conduit from a liquid fuel source, such as an oil tank, and an outlet connectable to an inlet of a liquid fuel metering device, said compressor having an outlet being connectable to the gas atomizing nozzle of the liquid fuel burner, is characterized in that the unit comprise a common drive shaft for the liquid fuel feed pump and the compressor.
- liquid fuel feed pump and the compressor both comprise a rotary impeller mounted on the common drive shaft.
- the unit comprises a motor with a rotor connected to the common drive shaft.
- the motor is placed between the compressor and the liquid fuel feed pump. This provides for more maintenance friendly unit as the compressor and liquid fuel feed pump will be readily accessible.
- the common drive shaft may be one element or it may comprise more interconnected shaft elements, which will facilitate manufacturing.
- the unit may comprise a modulatable liquid fuel metering device, which may comprise a metering orifice and a valve.
- the liquid fuel metering device is a metering pump, which may be a piston pump activated by an electro magnet.
- the compressor is a vane pump and the liquid fuel feed pump may be a gerotor pump.
- a liquid fuel burner system comprises a burner device with a gas atomizing burner nozzle, a fan for supplying combustion air to the burner device, and a liquid fuel supply unit, said unit being a constructional and exchangeable unit and comprising a liquid fuel feed pump and a compressor having a common drive shaft, the system further comprising a modulatable liquid fuel metering device fed by said liquid fuel feed pump, said gas atomizing burner nozzle being connected with the liquid fuel metering device and the compressor for receiving liquid fuel and atomising gas.
- the burner device preferably has a minimum heat output of less than 10 kW.
- FIG. 1 is an oblique view of a compressor
- FIG. 2 is an oblique view of a feed pump
- FIG. 3 is a side view of an assembled compressor-pump unit
- FIG. 4 is a cross-section along line IV-IV of the compressor-pump unit in FIG. 3 ,
- FIG. 5 is a partial section along the line V-V in FIG. 4 .
- FIG. 6 is a diagram showing fuel and air flows in a heating system utilizing the compressor-pump unit
- FIG. 7 is a diagram showing a preferred embodiment of a liquid fuel supply unit
- FIG. 8 shows a section corresponding to FIG. 5 but of a unit in a preferred embodiment.
- the present invention is embodied in a burner or heating system and a liquid fuel supply unit, such as may be used in pumping a low volume of fuel oil from a tank (not shown) to a burner nozzle in a household boiler.
- FIG. 6 shows diagrammatically a heating system with a liquid fuel supply unit 101 comprising a liquid fuel feed pump 102 connected to a metering device 103 and a compressor 104 .
- the liquid fuel supply unit 101 is described in more detail with reference to FIGS. 1-5 .
- the heating system comprises a gas atomizing nozzle 105 fed by the supply unit 101 , said nozzle 105 being attached to a burner 106 , which is supplied with combustion air by a fan 107 .
- the burner 106 is in turn attached to a boiler 108 of the domestic or household heating system.
- the boiler 108 and the fan 107 may be of any suitable art.
- the burner 106 and nozzle 105 may also be of a known art.
- the fuel supply unit 101 , the fan 107 , the nozzle 105 and the burner 106 together constitute a burner system.
- the compressor 104 can be seen in FIG. 1 in partly disassembled state.
- the compressor 104 is a vane pump having an impeller 2 mounted on a drive shaft 3 .
- the impeller 2 rotates in a housing 4 having an offset pump chamber 5 .
- On rotation of the impeller 2 movable vanes 6 of the impeller 2 follows the inner wall of the pump chamber 5 , so that gas, in the present example air, is drawn in through an inlet (not shown), compressed in the pump chamber 5 between the impeller 2 , the housing 4 and the vanes 6 , and delivered through an outlet (not shown).
- gas in the present example air
- the compressor 104 must obviously be equipped with some kind of cover covering the pump chamber.
- the feed pump 102 can be seen in partly disassembled state, as no cover is shown.
- the feed pump 102 is a gerotor pump (a kind of gear wheel pump known in the art) comprising a rotary impeller or gear wheel 8 mounted on the shaft 3 to be rotated thereby.
- the gear wheel 8 meshes with an internal toothing in an eccentrically mounted gear ring 9 , thereby defining pump chambers of varying size to pump a liquid, in this case fuel oil, from an inlet to an outlet.
- FIG. 2 also shows the metering device 103 , which in this embodiment is a metering pump, connected to the feed pump 102 .
- the bearing housing 11 of the feed pump 102 comprises conduits for delivering oil from the feed pump 102 to the metering device 103 and conduits for the oil delivered from the metering device 103 to a metered oil outlet 12 ( FIG. 4 ) in the bearing housing 11 .
- the feed pump 102 is mounted on the same drive shaft 3 as the compressor 104 , so that the housing of the feed pump 102 also act as cover for the compressor 104 .
- the bearing housing 11 of the feed pump 102 further comprises conduits for compressed air from the compressor 104 to an atomizing gas outlet 13 in the bearing housing 11 .
- gaskets 14 are provided between the housing 4 of the compressor 104 and the bearing housing 11 of the feed pump 7 .
- the gaskets 14 are preferably made of carbon fibre sheet material to provide low friction bearings for the impeller 2 and sealing of the housing 4 to hinder leakage of compressed air.
- the final assembly is the fuel supply unit 101 comprising the compressor 104 , the feed pump 102 and a covering 15 of the feed pump 102 can be seen in FIG. 3 , which is a side view of the assembly, and also the metering device 103 .
- the extending end of the shaft 3 ( FIGS. 1 and 2 ) can be connected to a preferably electric motor.
- the motor may be an external component, but preferably it is incorporated in the liquid fuel supply unit 101 as shown at 30 in FIG. 4 and 5 .
- the compressor 104 , the feed pump 102 and the motor 30 each have a rotor connected to the common shaft 3 .
- the metering device 103 is inserted deeply into the bearing housing 11 of the feed pump 102 .
- the metering device 103 which in this embodiment is a metering pump, comprises a piston 16 actuated by an electromagnet 17 .
- Oil delivered from the metering device 103 passes a one-way valve, in this case a ball 18 biased by a spring 19 to close off the discharge opening of the metering device 103 .
- the oil From the discharge opening of the metering device 103 , the oil enters a conduit 20 and continues to the outlet 12 .
- Oil for the feed pump 102 enters through an inlet 21 and flows through conduits (not shown) to the feed pump 102 .
- Excess oil from the feed pump 102 is directed to an outlet 22 through conduits (not shown) and through a pressure regulating valve 23 ensuring that the oil pressure before the metering device 103 is maintained at a desired level e.g. 0.5 bar overpressure (1.5 bar absolute pressure).
- the output of the metering device 103 can be modulated with a rate of capacity of 1:5 or more between minimum and maximum. The modulation may be performed gradually or stepwise (e.g. two or three stages).
- the shaft 3 is connected to the impeller 2 of the compressor and to the gear wheel 8 of the feed pump, which gear wheel 8 meshes with an internal toothing of a gear ring 9 .
- the impeller 2 comprises vanes 6 and rotates in the chamber 5 of the housing 4 of the compressor.
- a conduit 24 for oil delivery to the metering device 103 is formed, whereas excess oil from the pump returns through a conduit 25 to the outlet 22 (see FIG. 4 ).
- the burner system will comprise means for regulation including means for controlling the output from the metering device 103 and means for controlling the output of the fan 107 to obtain a proper relationship between the feeding rates of fuel oil and combustion air.
- the supply unit for a burner of a domestic boiler operates with a feed pump delivering oil for the metering device at a rate of 20 l/h and at a pressure of 0.5 bar (overpressure). Oil for the burner is delivered by the metering device delivering oil at a rate of down to 0.5 l/h at an overpressure of 0.5 bar.
- the metering device is a piston pump, in which the piston is activated by an electromagnet, and the piston has a displacement of 2.8 mm 3 per stroke, which at a frequency of 50 Hz gives the above mentioned flow rate.
- the compressor delivers atomizing air at a rate of 1.3 m 3 /h at a pressure of 0.3 bar. With this supply unit it is possible to obtain an output of the burner of less than 10 kW at continuous operation of the burner.
- the preferred embodiment of the liquid fuel supply unit of the present invention comprises as a metering device an orifice and a valve with a device for opening and closing said valve at intervals according to a heating demand.
- FIG. 7 shows a liquid fuel supply unit 101 ′ comprising a liquid fuel feed pump 102 ′, a compressor 104 ′ and a motor 30 ′ for driving the feed pump 102 ′ and the compressor 104 ′ through a common shaft 3 ′.
- the motor 30 ′ is situated between the compressor 104 ′ and the liquid fuel feed pump 102 ′.
- the common shaft 3 ′ may be one element, or it may comprise two or three elements interconnected by couplings, possibly elastic couplings as it is known in the art to compensate for minor misalignments.
- An outlet of the feed pump 102 is through a conduit 201 connected to a metering device 103 ′ comprising a shut-off valve 202 and an orifice 203 .
- a conduit 204 leads fuel metered by the valve 202 and the orifice 203 to the gas atomizing nozzle 105 and a conduit 205 leads atomizing air from the compressor 104 ′ to the nozzle 105 .
- FIG. 7 also shows a pressure regulating valve 206 for regulating a pressure drop over the orifice 203 and for draining excess oil delivered from the feed pump 102 ′.
- FIG. 8 shows a section of a unit in the preferred embodiment.
- the shaft 3 ′ is connected to the impeller 2 of the compressor 104 ′ and to the gear wheel 8 of the feed pump 102 ′, which gear wheel 8 meshes with an internal toothing of a gear ring 9 .
- the impeller 2 comprises vanes 6 and rotates in the chamber 5 of the housing 4 of the compressor.
- a conduit 24 for oil delivery to the metering device 103 is formed, whereas excess oil from the pump returns through a conduit 25 to the outlet.
- the electric motor 30 ′ is situated between the compressor 104 ′ and the liquid fuel feed pump 102 ′ and comprises a rotor 31 connected to the shaft 3 ′ and a stator 32 .
- the modulation of the rate of feeding fuel to the nozzle 105 is performed by keeping a predetermined pressure differential across the orifice 203 (and the shut-off valve 202 ) by means of the pressure regulating valve 206 and opening and closing the shut-off valve 202 to meter or to deliver fuel to the orifice at a pulsing rate in accordance with heat demand.
- This mode of operation provides for modulating the heat output from a low output of approximately 1 kW (corresponding to approximately 0.16 l/h fuel oil) to a high output of 10-20 kW or more.
- shut-off valve 207 may be kept open and the fuel delivery rate be regulated (metered) by regulating the pressure differential across the orifice 208 by means of the pressure regulating valve 211 .
- the compressor 104 and the feed pump 102 may be run at a constant rate.
- a constant output from the compressor 104 of 30 l/h at 0.3 bar overpressure could be used. This rate corresponds to the need for combustion air at the low heat output of approximately 1 kW.
- the combustion air fan may be turned off when the output from the metering device is modulated to its lower limit.
- the described compact design of the supply unit as a constructional unit provides for easy assemblage during production of burners and also makes the supply unit ideal for retrofitting on an existing boiler for domestic use, possibly at a change from using gaseous fuel, such as natural gas, to a liquid fuel, such as fuel oil. Further the gathering of components: liquid fuel feed pump, compressor and possibly a liquid fuel metering device in a unit provides for easy exchange of such unit if necessary.
- a piston pump possibly with commutation, could be used either driven by a separate motor or by the motor driving the compressor and the feed pump. If driven by a separate motor the metering may be modulated by varying the speed of the motor. Otherwise modulation may be obtained by varying the commutation.
- gear wheel pump with either internal or external gearing teeth, possibly with commutation, could be used either driven by a separate motor or by the motor driving the compressor and the feed pump. If driven by a separate motor the metering may be modulated by varying the speed of the motor. Otherwise modulation may be obtained by varying the commutation.
- the invention is not restricted to the use of oil as the liquid fuel, and would work well with other kinds of liquid fuel. Further, the invention is not restricted to the use of air as the atomizing gas, other kinds of gases, e.g. an inert gas, such as nitrogen, or a gaseous fuel, such as propane, could be used if this should be advantageous in the given situation.
- gases e.g. an inert gas, such as nitrogen, or a gaseous fuel, such as propane, could be used if this should be advantageous in the given situation.
Abstract
Description
- This application is entitled to the benefit of and incorporates by reference essential subject matter disclosed in international Patent Application No. PCT/DK2003/000733 filed on Oct. 30, 2003 and Danish Patent Application No. PA 2002 01684 filed on Nov. 1, 2002.
- The present invention relates to a liquid fuel supply unit for a liquid fuel burner and a liquid fuel burner system. Especially the invention relates to domestic heating the liquid fuel burner having a heat output of less than 10 kW.
- Liquid fuel burners, such as oil burners, are quite common for domestic use. Ordinarily such oil burners are of the oil pressure atomizing type having high-pressure pumps delivering oil at high pressure. These burners operate on the principle that when oil under pressure is permitted to expand through a small orifice, it tends to break into a spray of very fine droplets, which are suitable for combustion. These burners are usually designed to operate with oil pressure as high as 3 MPa and viscosities of from 2 cSt. The principle upon which these burners operate requires that the pressure drop across the orifice be maintained high and as nearly constant as possible in order to achieve the necessary fine atomized droplets and also to avoid pulsating combustion. Because it is not possible to maintain the required atomization at lower pressure drop and thus lower flow, modulation or regulation of the heat output, in the operation of such burners has traditionally been very severely limited or has not been used at all, and the burners have been operated in an on-off mode only. This results in inferior temperature control, lower boiler efficiency and increased thermal load of the components, as they will experience a lot of heating and cooling cycles. On-off regulation also has a detrimental impact on the environments due to the many start-ups during which the combustion of the fuel is not optimal.
- The minimum output of the burner is controlled by the size of the holes in the orifice. The smallest feasible holes are 0.1 mm in diameter, as smaller holes will clog very quickly due to inevitable particles in the oil or due to soot build-up from the combustion, increasing the need for maintenance to an intolerable level. The ordinary minimum output of oil burners having an orifice with the smallest holes possible, is about 10 kW, which exceeds the static demand of an ordinary household.
- One such oil burner is known from U.S. Pat. No. 5,692,680, which discloses a fuel supply unit for an oil burner. This fuel supply unit comprises a pump delivering pressurized fuel to a metering orifice, where the flow rate of fuel delivered can be regulated by regulating the pressure differential to maintain a constant flow independently of the elevation of the burner and the elevation of the tank with respect to the pumping unit. However, it is generally advantageous to have an adjustable flow rate of fuel to the burner, therefore this kind of supply unit is not desirable.
- It has also been proposed to use burners in which a liquid fuel is gasified prior to the supply to the burner. These burners, however, require a significant start-up time, as the fuel must be heated to gasification temperature prior to start-up of the burner, and this kind of burners are mainly used for large industrial burners.
- It has also been tried to operate liquid fuel burners on foamed liquid fuel. One such burner is disclosed in U.S. Pat. No. 5,051,090 wherein the liquid fuel is foamed in a foam collection cylinder. This kind of burner is, however, only suited for large industrial burners.
- EP-A-0 556 694 discloses a burner system for liquid fuel and provided for easy modulation to compensate for changes in fuel viscosity. The burner system thus comprises a gas atomizing nozzle fed by an air compressor and a fuel pump, the fuel being fed through a regulator regulating on basis of a pressure difference.
- U.S. Pat. No. 4,391,580 discloses a system for supplying fuel to a pressure atomization fuel oil burner nozzle comprising a rotating gear pump with a rotatable valving structure for delivering fuel at pressure pulses and at a rate depending on the rotational speed of the pump, the rate thus being controllable. The system further comprises a blower driven by the same motor as the pump.
- EP-A-0 013 488 discloses a unit comprising a fuel oil pump, a fan and a motor mounted on a common shaft and an electric circuit for controlling the unit.
- As oil and most other liquid fuels are fossil fuels and hence a scarce resource, care should be taken to exploit the fuel to the utmost.
- The object of the present invention is to provide a liquid fuel burner system which when applied to a boiler of a domestic heating system allows substantially continuous, modulate operation at least during the heating season.
- A further object is to provide a unit for use in such a system.
- According to the invention a liquid fuel supply unit for a liquid fuel burner with a gas atomizing nozzle, the supply unit comprising a liquid fuel feed pump and a compressor, said liquid fuel feed pump having an inlet connectable to a liquid fuel conduit from a liquid fuel source, such as an oil tank, and an outlet connectable to an inlet of a liquid fuel metering device, said compressor having an outlet being connectable to the gas atomizing nozzle of the liquid fuel burner, is characterized in that the unit comprise a common drive shaft for the liquid fuel feed pump and the compressor. Hereby is obtained a unit which provides for low production costs and thus makes it feasible to provide a system according to the invention.
- Preferably the liquid fuel feed pump and the compressor both comprise a rotary impeller mounted on the common drive shaft.
- Also preferably the unit comprises a motor with a rotor connected to the common drive shaft. Preferably the motor is placed between the compressor and the liquid fuel feed pump. This provides for more maintenance friendly unit as the compressor and liquid fuel feed pump will be readily accessible.
- The common drive shaft may be one element or it may comprise more interconnected shaft elements, which will facilitate manufacturing.
- Further the unit may comprise a modulatable liquid fuel metering device, which may comprise a metering orifice and a valve. Alternatively the liquid fuel metering device is a metering pump, which may be a piston pump activated by an electro magnet.
- In a preferred embodiment the compressor is a vane pump and the liquid fuel feed pump may be a gerotor pump.
- A liquid fuel burner system according to the invention comprises a burner device with a gas atomizing burner nozzle, a fan for supplying combustion air to the burner device, and a liquid fuel supply unit, said unit being a constructional and exchangeable unit and comprising a liquid fuel feed pump and a compressor having a common drive shaft, the system further comprising a modulatable liquid fuel metering device fed by said liquid fuel feed pump, said gas atomizing burner nozzle being connected with the liquid fuel metering device and the compressor for receiving liquid fuel and atomising gas.
- By means of the system according to the invention it is economically feasible to run a domestic heating device with a boiler and a liquid fuel burner continuously during the heating season, thus avoiding the drawbacks related to operation in on-off mode.
- Thus the burner device preferably has a minimum heat output of less than 10 kW.
- In the following, the invention will be explained in more detail by means of embodiments and with reference to the accompanying drawing, in which
-
FIG. 1 is an oblique view of a compressor, -
FIG. 2 is an oblique view of a feed pump, -
FIG. 3 is a side view of an assembled compressor-pump unit, -
FIG. 4 is a cross-section along line IV-IV of the compressor-pump unit inFIG. 3 , -
FIG. 5 is a partial section along the line V-V inFIG. 4 , -
FIG. 6 is a diagram showing fuel and air flows in a heating system utilizing the compressor-pump unit, -
FIG. 7 is a diagram showing a preferred embodiment of a liquid fuel supply unit, and -
FIG. 8 shows a section corresponding toFIG. 5 but of a unit in a preferred embodiment. - For purposes of illustration, the present invention is embodied in a burner or heating system and a liquid fuel supply unit, such as may be used in pumping a low volume of fuel oil from a tank (not shown) to a burner nozzle in a household boiler.
- Thus
FIG. 6 shows diagrammatically a heating system with a liquidfuel supply unit 101 comprising a liquidfuel feed pump 102 connected to ametering device 103 and acompressor 104. The liquidfuel supply unit 101 is described in more detail with reference toFIGS. 1-5 . Further the heating system comprises agas atomizing nozzle 105 fed by thesupply unit 101, saidnozzle 105 being attached to aburner 106, which is supplied with combustion air by afan 107. Theburner 106 is in turn attached to aboiler 108 of the domestic or household heating system. Theboiler 108 and thefan 107 may be of any suitable art. Theburner 106 andnozzle 105 may also be of a known art. - The
fuel supply unit 101, thefan 107, thenozzle 105 and theburner 106 together constitute a burner system. - The
compressor 104 can be seen inFIG. 1 in partly disassembled state. Thecompressor 104 is a vane pump having animpeller 2 mounted on adrive shaft 3. Theimpeller 2 rotates in ahousing 4 having an offsetpump chamber 5. On rotation of theimpeller 2movable vanes 6 of theimpeller 2 follows the inner wall of thepump chamber 5, so that gas, in the present example air, is drawn in through an inlet (not shown), compressed in thepump chamber 5 between theimpeller 2, thehousing 4 and thevanes 6, and delivered through an outlet (not shown). To function thecompressor 104 must obviously be equipped with some kind of cover covering the pump chamber. - In
FIG. 2 thefeed pump 102 can be seen in partly disassembled state, as no cover is shown. Thefeed pump 102 is a gerotor pump (a kind of gear wheel pump known in the art) comprising a rotary impeller orgear wheel 8 mounted on theshaft 3 to be rotated thereby. Thegear wheel 8 meshes with an internal toothing in an eccentrically mountedgear ring 9, thereby defining pump chambers of varying size to pump a liquid, in this case fuel oil, from an inlet to an outlet.FIG. 2 also shows themetering device 103, which in this embodiment is a metering pump, connected to thefeed pump 102. The bearinghousing 11 of thefeed pump 102 comprises conduits for delivering oil from thefeed pump 102 to themetering device 103 and conduits for the oil delivered from themetering device 103 to a metered oil outlet 12 (FIG. 4 ) in the bearinghousing 11. As may be appreciated fromFIG. 5 or when comparingFIGS. 1 and 2 , thefeed pump 102 is mounted on thesame drive shaft 3 as thecompressor 104, so that the housing of thefeed pump 102 also act as cover for thecompressor 104. The bearinghousing 11 of thefeed pump 102 further comprises conduits for compressed air from thecompressor 104 to anatomizing gas outlet 13 in the bearinghousing 11. Between thehousing 4 of thecompressor 104 and the bearinghousing 11 of the feed pump 7,gaskets 14 are provided. Thegaskets 14 are preferably made of carbon fibre sheet material to provide low friction bearings for theimpeller 2 and sealing of thehousing 4 to hinder leakage of compressed air. - The final assembly is the
fuel supply unit 101 comprising thecompressor 104, thefeed pump 102 and a covering 15 of thefeed pump 102 can be seen inFIG. 3 , which is a side view of the assembly, and also themetering device 103. The extending end of the shaft 3 (FIGS. 1 and 2 ) can be connected to a preferably electric motor. The motor may be an external component, but preferably it is incorporated in the liquidfuel supply unit 101 as shown at 30 inFIG. 4 and 5. Thus thecompressor 104, thefeed pump 102 and themotor 30 each have a rotor connected to thecommon shaft 3. - In the section of
FIG. 4 , it can be seen that themetering device 103 is inserted deeply into the bearinghousing 11 of thefeed pump 102. Themetering device 103, which in this embodiment is a metering pump, comprises apiston 16 actuated by anelectromagnet 17. Oil delivered from themetering device 103 passes a one-way valve, in this case aball 18 biased by aspring 19 to close off the discharge opening of themetering device 103. From the discharge opening of themetering device 103, the oil enters aconduit 20 and continues to theoutlet 12. Oil for thefeed pump 102 enters through aninlet 21 and flows through conduits (not shown) to thefeed pump 102. Excess oil from thefeed pump 102 is directed to anoutlet 22 through conduits (not shown) and through apressure regulating valve 23 ensuring that the oil pressure before themetering device 103 is maintained at a desired level e.g. 0.5 bar overpressure (1.5 bar absolute pressure). The output of themetering device 103 can be modulated with a rate of capacity of 1:5 or more between minimum and maximum. The modulation may be performed gradually or stepwise (e.g. two or three stages). - In the section of
FIG. 5 , it can be seen that theshaft 3 is connected to theimpeller 2 of the compressor and to thegear wheel 8 of the feed pump, whichgear wheel 8 meshes with an internal toothing of agear ring 9. Theimpeller 2 comprisesvanes 6 and rotates in thechamber 5 of thehousing 4 of the compressor. In the bearinghousing 11 of the feed pump, aconduit 24 for oil delivery to themetering device 103 is formed, whereas excess oil from the pump returns through aconduit 25 to the outlet 22 (seeFIG. 4 ). - The burner system will comprise means for regulation including means for controlling the output from the
metering device 103 and means for controlling the output of thefan 107 to obtain a proper relationship between the feeding rates of fuel oil and combustion air. - In an example the supply unit, as disclosed with reference to
FIGS. 1-5 , for a burner of a domestic boiler operates with a feed pump delivering oil for the metering device at a rate of 20 l/h and at a pressure of 0.5 bar (overpressure). Oil for the burner is delivered by the metering device delivering oil at a rate of down to 0.5 l/h at an overpressure of 0.5 bar. The metering device is a piston pump, in which the piston is activated by an electromagnet, and the piston has a displacement of 2.8 mm3 per stroke, which at a frequency of 50 Hz gives the above mentioned flow rate. The compressor delivers atomizing air at a rate of 1.3 m3/h at a pressure of 0.3 bar. With this supply unit it is possible to obtain an output of the burner of less than 10 kW at continuous operation of the burner. - In stead of a metering pump the preferred embodiment of the liquid fuel supply unit of the present invention comprises as a metering device an orifice and a valve with a device for opening and closing said valve at intervals according to a heating demand.
- Thus
FIG. 7 shows a liquidfuel supply unit 101′ comprising a liquidfuel feed pump 102′, acompressor 104′ and amotor 30′ for driving thefeed pump 102′ and thecompressor 104′ through acommon shaft 3′. Themotor 30′is situated between thecompressor 104′ and the liquidfuel feed pump 102′. Thecommon shaft 3′ may be one element, or it may comprise two or three elements interconnected by couplings, possibly elastic couplings as it is known in the art to compensate for minor misalignments. An outlet of thefeed pump 102 is through aconduit 201 connected to ametering device 103′ comprising a shut-offvalve 202 and anorifice 203. Aconduit 204 leads fuel metered by thevalve 202 and theorifice 203 to thegas atomizing nozzle 105 and aconduit 205 leads atomizing air from thecompressor 104′ to thenozzle 105.FIG. 7 also shows apressure regulating valve 206 for regulating a pressure drop over theorifice 203 and for draining excess oil delivered from thefeed pump 102′. -
FIG. 8 shows a section of a unit in the preferred embodiment. For corresponding parts the same reference numerals are used as inFIG. 5 . It can be seen that theshaft 3′ is connected to theimpeller 2 of thecompressor 104′ and to thegear wheel 8 of thefeed pump 102′, whichgear wheel 8 meshes with an internal toothing of agear ring 9. Theimpeller 2 comprisesvanes 6 and rotates in thechamber 5 of thehousing 4 of the compressor. In the bearinghousing 11 of the feed pump, aconduit 24 for oil delivery to themetering device 103 is formed, whereas excess oil from the pump returns through aconduit 25 to the outlet. Theelectric motor 30′ is situated between thecompressor 104′ and the liquidfuel feed pump 102′ and comprises arotor 31 connected to theshaft 3′ and astator 32. - In the preferred embodiment shown in
FIG. 7 the modulation of the rate of feeding fuel to thenozzle 105 is performed by keeping a predetermined pressure differential across the orifice 203 (and the shut-off valve 202) by means of thepressure regulating valve 206 and opening and closing the shut-offvalve 202 to meter or to deliver fuel to the orifice at a pulsing rate in accordance with heat demand. This mode of operation provides for modulating the heat output from a low output of approximately 1 kW (corresponding to approximately 0.16 l/h fuel oil) to a high output of 10-20 kW or more. - In the alternative the shut-off valve 207 may be kept open and the fuel delivery rate be regulated (metered) by regulating the pressure differential across the orifice 208 by means of the pressure regulating valve 211.
- Whereas the delivery rates of fuel oil from the
metering deice 103 and combustion air from thefan 107 are modulated according to heat effect needs, thecompressor 104 and thefeed pump 102 may be run at a constant rate. Thus a constant output from thecompressor 104 of 30 l/h at 0.3 bar overpressure could be used. This rate corresponds to the need for combustion air at the low heat output of approximately 1 kW. Thus the combustion air fan may be turned off when the output from the metering device is modulated to its lower limit. - The described compact design of the supply unit as a constructional unit provides for easy assemblage during production of burners and also makes the supply unit ideal for retrofitting on an existing boiler for domestic use, possibly at a change from using gaseous fuel, such as natural gas, to a liquid fuel, such as fuel oil. Further the gathering of components: liquid fuel feed pump, compressor and possibly a liquid fuel metering device in a unit provides for easy exchange of such unit if necessary.
- In case a metering pump is used several alternatives to the above-mentioned metering pump are envisaged:
- A piston pump, possibly with commutation, could be used either driven by a separate motor or by the motor driving the compressor and the feed pump. If driven by a separate motor the metering may be modulated by varying the speed of the motor. Otherwise modulation may be obtained by varying the commutation.
- Also a gear wheel pump with either internal or external gearing teeth, possibly with commutation, could be used either driven by a separate motor or by the motor driving the compressor and the feed pump. If driven by a separate motor the metering may be modulated by varying the speed of the motor. Otherwise modulation may be obtained by varying the commutation.
- The invention is not restricted to the use of oil as the liquid fuel, and would work well with other kinds of liquid fuel. Further, the invention is not restricted to the use of air as the atomizing gas, other kinds of gases, e.g. an inert gas, such as nitrogen, or a gaseous fuel, such as propane, could be used if this should be advantageous in the given situation.
- While the present invention has been illustrated and described with respect to a particular embodiment thereof, it should be appreciated by those of ordinary skill in the art that various modifications to this invention may be made without departing from the spirit and scope of the present invention.
Claims (13)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DKPA200201684 | 2002-11-01 | ||
DKPA200201684 | 2002-11-01 | ||
PCT/DK2003/000733 WO2004040192A1 (en) | 2002-11-01 | 2003-10-30 | A liquid fuel supply unit for a liquid fuel burner and a liquid fuel burner system |
Publications (1)
Publication Number | Publication Date |
---|---|
US20060147855A1 true US20060147855A1 (en) | 2006-07-06 |
Family
ID=32187138
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/533,142 Abandoned US20060147855A1 (en) | 2002-11-01 | 2003-10-30 | Liquid fuel supply unit for a liquid fuel burner and a liquid fuel burner system |
Country Status (7)
Country | Link |
---|---|
US (1) | US20060147855A1 (en) |
EP (1) | EP1576316A1 (en) |
JP (1) | JP2006504921A (en) |
KR (1) | KR100711048B1 (en) |
CN (1) | CN1711446A (en) |
AU (1) | AU2003277825A1 (en) |
WO (1) | WO2004040192A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090218409A1 (en) * | 2008-02-29 | 2009-09-03 | Wen-Lo Chen | Heating system for motor vehicle |
CN102252321A (en) * | 2011-05-17 | 2011-11-23 | 苏州辰昌新能源技术有限公司 | Combustion device |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
ITBO20120128A1 (en) | 2012-03-13 | 2013-09-14 | Riello Spa | COMBUSTION EQUIPMENT OF LIQUID FUELS AND ITS METHOD TO MODULATE THE POWER OF SUCH EQUIPMENT |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2117512A (en) * | 1935-03-28 | 1938-05-17 | Lewis L Scott | Oil burner |
US2760564A (en) * | 1956-08-28 | Fuel supply system for oil burners - | ||
US2832403A (en) * | 1955-09-20 | 1958-04-29 | Sundstrand Machine Tool Co | Air-oil unit |
US4255093A (en) * | 1979-03-23 | 1981-03-10 | Sundstrand Corporation | Combined lift and metering pump |
US4391580A (en) * | 1980-12-08 | 1983-07-05 | Sundstrand Corporation | Liquid fuel supply system for an atomization burner nozzle |
US4994984A (en) * | 1987-03-31 | 1991-02-19 | Tecnolab Snc Di Sanna Massimo & C. | System and device for supplying desired liquid volumes by means of a metering pump in variable flow rate condition |
US5692680A (en) * | 1995-03-17 | 1997-12-02 | Suntec Industries Incorporated | Fuel supply unit for an oil burner |
US20020098394A1 (en) * | 2000-10-27 | 2002-07-25 | Keefer Bowie G. | Systems and processes for providing hydrogen to fuel cells |
-
2003
- 2003-10-30 CN CNA2003801028305A patent/CN1711446A/en active Pending
- 2003-10-30 WO PCT/DK2003/000733 patent/WO2004040192A1/en active Application Filing
- 2003-10-30 EP EP03769249A patent/EP1576316A1/en not_active Withdrawn
- 2003-10-30 JP JP2004547446A patent/JP2006504921A/en active Pending
- 2003-10-30 AU AU2003277825A patent/AU2003277825A1/en not_active Abandoned
- 2003-10-30 KR KR1020057007726A patent/KR100711048B1/en not_active IP Right Cessation
- 2003-10-30 US US10/533,142 patent/US20060147855A1/en not_active Abandoned
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2760564A (en) * | 1956-08-28 | Fuel supply system for oil burners - | ||
US2117512A (en) * | 1935-03-28 | 1938-05-17 | Lewis L Scott | Oil burner |
US2832403A (en) * | 1955-09-20 | 1958-04-29 | Sundstrand Machine Tool Co | Air-oil unit |
US4255093A (en) * | 1979-03-23 | 1981-03-10 | Sundstrand Corporation | Combined lift and metering pump |
US4391580A (en) * | 1980-12-08 | 1983-07-05 | Sundstrand Corporation | Liquid fuel supply system for an atomization burner nozzle |
US4994984A (en) * | 1987-03-31 | 1991-02-19 | Tecnolab Snc Di Sanna Massimo & C. | System and device for supplying desired liquid volumes by means of a metering pump in variable flow rate condition |
US5692680A (en) * | 1995-03-17 | 1997-12-02 | Suntec Industries Incorporated | Fuel supply unit for an oil burner |
US20020098394A1 (en) * | 2000-10-27 | 2002-07-25 | Keefer Bowie G. | Systems and processes for providing hydrogen to fuel cells |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090218409A1 (en) * | 2008-02-29 | 2009-09-03 | Wen-Lo Chen | Heating system for motor vehicle |
CN102252321A (en) * | 2011-05-17 | 2011-11-23 | 苏州辰昌新能源技术有限公司 | Combustion device |
Also Published As
Publication number | Publication date |
---|---|
JP2006504921A (en) | 2006-02-09 |
EP1576316A1 (en) | 2005-09-21 |
WO2004040192A1 (en) | 2004-05-13 |
KR20050061598A (en) | 2005-06-22 |
KR100711048B1 (en) | 2007-04-24 |
CN1711446A (en) | 2005-12-21 |
AU2003277825A1 (en) | 2004-05-25 |
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