Method and Apparatus for Controlling and Regulating Flow of Fuel Oil in Heating Systems

Abstract

A fuel oil burner for a heating system includes a nozzle having an inlet and outlet, and an electric solenoid valve having an inlet for receiving pressurized fuel oil from a fuel supply system and an outlet in communication with the inlet of the nozzle. The valve is configured to prevent flow of fuel oil through the valve to the nozzle in a closed state and to permit flow of fuel oil through the valve to the nozzle in an open state. A controller in communication with the valve is configured to intermittently switch the valve between the closed state and the open state at predetermined time periods so that pulses of fuel oil exit the outlet of the nozzle. The valve is intermittently in the closed state a time period so that the pulses of fuel oil exiting the outlet of the nozzle self-sustain a flame.

Description

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

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PARTIES TO A JOINT RESEARCH AGREEMENT

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REFERENCE TO APPENDIX

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FIELD OF THE INVENTION

The field of the present invention generally relates to heating systems and, more particularly, to heating systems having oil burners.

BACKGROUND OF THE INVENTION

Oil burners are employed in various types of heating systems such as, for example, home furnaces, water heaters, and the like. In such systems, the oil burner receives fuel oil (sometimes referred to as “heating oil”) and initiates combustion of the fuel oil to generate heat. The heat is then used in various manners to perform work such as, for example, to warm air or water to desired temperatures.

As fuel oil prices rise, fuel oil consumers typically become more cost and efficiency conscious. However, their options are typically limited to reducing heat within their house so that less fuel oil is burned, switching to a replacement fuel such as “blended oil”, or replacing their heating system with a heating system using another available type of fuel. Obviously using reduced heat during the winter is not a very desirable option. Additionally, using “blended oil” such as, for example, fuel oil blended with waste oils typically results in reduced efficiency and a higher level of pollution. In some cases, the “blended oil” can create sludge which results in the necessary disassembly of the heating system for cleaning. Furthermore, obtaining a heating system that utilizes a different type of fuel can be extremely costly and/or difficult if there is not a readily available alternative fuel at the geographic location of the homeowner.

Accordingly, there is a need for improved methods and apparatus for controlling and regulating flow of fuel oil in heating systems that reduce fuel oil usage while producing an equivalent quantity of heat as prior art heating systems.

SUMMARY OF THE INVENTION

Disclosed are methods and apparatus for controlling and regulating flow of fuel oil in heating systems which address one or more issues of the related art. Disclosed is a fuel oil burner for a heating system. The fuel oil burner comprises, in combination, a nozzle having an inlet and outlet and configured to atomize fuel oil and an electric solenoid valve having an inlet for fluid-flow communication with a pressurized source of fuel oil and an outlet in fluid-flow communication with the inlet of the nozzle. The electric solenoid valve is configured so that flow of fuel oil from the inlet of the electric solenoid valve to the inlet of the nozzle is prevented in a closed state of the electric solenoid valve and fuel oil flows from the inlet of the electric solenoid valve to the inlet of the nozzle in an open state of the electric solenoid valve. A controller is in electrical communication with the electric solenoid valve and is configured to intermittently change the valve between the closed state and the open state at predetermined time periods so that pulses of fuel oil exit the outlet of the nozzle. The electric solenoid valve is intermittently in the closed state a time period so that the pulses of fuel oil exiting the outlet of the nozzle self-sustain a flame.

Also disclosed is a method for controlling and regulating flow of fuel oil in a heating system. The method comprises the steps of, in combination, obtaining a nozzle having an inlet and outlet and configured to atomize fuel oil and obtaining an electric solenoid valve having an inlet for fluid-flow communication with a pressurized source of fuel oil and an outlet in fluid-flow communication with the inlet of the nozzle. The electric solenoid valve is configured so that flow of fuel oil from the inlet of the electric solenoid valve to the inlet of the nozzle is prevented in a closed state of the electric solenoid valve and fuel oil flows from the inlet of the electric solenoid valve to the inlet of the nozzle in an open state of the electric solenoid valve. The steps further comprise intermittently changing the valve between the closed state and the open state at predetermined time periods so that pulses of fuel oil exit the outlet of the nozzle. The electric solenoid valve is intermittently in the closed state a time period so that the pulses of fuel oil exiting the outlet of the nozzle self-sustain a flame.

Also disclosed is a domestic furnace apparatus comprising, in combination, a combustion chamber, a nozzle having an inlet and outlet in communication with the combustion chamber and configured to atomize fuel oil, and an electric solenoid valve having an inlet for fluid-flow communication with a pressurized source of fuel oil and an outlet in fluid-flow communication with the inlet of the nozzle. The electric solenoid valve is configured so that flow of fuel oil from the inlet of the electric solenoid valve to the inlet of the nozzle is prevented in a closed state of the electric solenoid valve and fuel oil flows from the inlet of the electric solenoid valve to the inlet of the nozzle in an open state of the electric solenoid valve. A controller is in electrical communication with the electric solenoid valve and configured to intermittently change the valve between the closed state and the open state at a predetermined time periods so that pulses of fuel oil exit the outlet of the nozzle. The electric solenoid valve is intermittently in the closed state a time period so that the pulses of fuel oil exiting the outlet of the nozzle self-sustain a flame within the combustion chamber.

From the foregoing disclosure and the following more detailed description of various preferred embodiments it will be apparent to those skilled in the art that the present invention provides a significant advance in the technology and art of heating systems having fuel oil burners. Particularly significant in this regard is the potential the invention affords for providing an economic and efficient heating system that reduce fuel oil usage while producing an equivalent quantity of heat as prior art heating systems. Additional features and advantages of various preferred embodiments will be better understood in view of the detailed description provided below.

BRIEF DESCRIPTION OF THE DRAWINGS

These and further features of the present invention will be apparent with reference to the following description and drawings.

FIG. 1 is a schematic view of a heating system having a fuel oil burner according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a normally-closed solenoid valve of the fuel oil burner of the heating system of FIG. 1, wherein the solenoid valve is in a closed or deenergized state.

FIG. 3 an enlarged cross-sectional view of the normally-closed solenoid valve of FIG. 2, but wherein the solenoid valve is in an open or energized state.

FIG. 4 is schematic view of a control signal for a pulsed fuel oil spray from a nozzle of the fuel oil burner of the heating system of FIG. 1.

FIG. 5 is schematic view of an alternative control signal for a pulsed fuel oil spray similar to FIG. 4 but for an alternative pulsed fuel oil spray.

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of the heating systems as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes of the various components, will be determined in part by the particular intended application and use environment. Certain features of the illustrated embodiments have been enlarged or distorted relative to others to facilitate visualization and clear understanding. In particular, thin features may be thickened, for example, for clarity or illustration. All references to direction and position, unless otherwise indicated, refer to the orientation of the heating systems illustrated in the drawings.

DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS

It will be apparent to those skilled in the art, that is, to those who have knowledge or experience in this area of technology, that many uses and design variations are possible for the apparatus and methods disclosed herein. The following detailed discussion of various alternative and preferred embodiments will illustrate the general principles of the invention. Other embodiments suitable for other applications will be apparent to those skilled in the art given the benefit of this disclosure.

Referring now to the drawings, FIG. 1 schematically shows a heating system 10 in the form of a domestic furnace having a fuel oil burner 12 according to the present invention. The illustrated fuel oil burner 12 includes an intermittent or pulsing fuel injector 14 including a nozzle 16 having an inlet and outlet 18, 20 and configured to atomize fuel oil into a combustion chamber 22, and an electric solenoid valve 24 having an inlet 26 for fluid-flow communication with a fuel supply system 28 providing pressurized fuel oil and an outlet 30 in fluid-flow communication with the inlet 18 of the nozzle 16. The illustrated fuel oil burner 12 additionally includes an electronic driver or controller 32 in electrical communication with the electric solenoid valve 24 and configured to intermittently change or switch the electric solenoid valve 24 between a closed state and an open state at a predetermined high frequency with predetermined open and closed time periods so that pulses of fuel oil exit the outlet 20 of the nozzle 16 into the combustion chamber 22 to form a self-supporting flame 34. The electric solenoid valve 24 is intermittently in the closed state a predetermined time period 36 and in the open state a predetermined period of time 38 so that the pulses of fuel oil exiting the outlet 20 of the nozzle 16, self-sustain the flame 34 as described in more detail hereinbelow. That is, the flame 34 is not extinguished or quenched by the pulsating fuel oil.

Pressurized fuel oil flows from the inlet 18 to the outlet 20 of the illustrated nozzle 16. The illustrated nozzle 16 is configured to atomize the fuel oil by forcing it through a small opening to inject a pulsed or intermittent stream of atomized fuel oil into the combustion chamber 22. It is noted that the nozzle 16 can alternatively be of any other suitable type.

The illustrated electric solenoid valve is a fast-action electric solenoid valve 24. The illustrated electric solenoid valve 24 is configured so that flow of fuel oil from the inlet 26 of the electric solenoid valve 24 to the inlet 18 of the nozzle 16 is prevented in a closed state of the electric solenoid valve 24 and fuel oil flows from the inlet 26 of the electric solenoid valve 24 to the inlet 18 of the nozzle 16 in an open state of the electric solenoid valve 24. The illustrated electric solenoid valve 24 is a normally-closed electronic solenoid valve configured so that flow of fuel oil from the inlet 26 to the outlet 30, and to the inlet 16 of the nozzle 18 connected thereto, is prevented when the electric solenoid valve 24 is un-energized or de-energized and fuel oil flows from the inlet 26 to the outlet 30, and to the inlet 18 of the nozzle 18 connected thereto, when the electric solenoid valve 24 is energized. It is noted that the electric solenoid valve 24 can alternatively be of any other suitable type. It is also noted that the electric solenoid valve and the nozzle can be integrated into a single housing.

FIGS. 2 and 3 show an exemplary fast-action, normally-closed, electric solenoid Valve 24. In the closed position, a coil 40 is de-energized or in a no-voltage condition and a valve element or plunger 42 is in contact with a valve seat 44 to fully close a valve orifice 46 due to preloading of a return spring 48 (shown in FIG. 2). In this arrangement, the electric solenoid valve 24 is closed and no fuel oil flows through the electric solenoid valve 24 because the fuel oil cannot pass through the valve orifice 46 to flow from the inlet 26 to the outlet 30. When the coil 40 is activated by providing voltage to the coil 40, the electric solenoid valve 24 switches to the open position because the coil 40 is energized or in a voltage condition. When the coil 40 is energized, a magnetic field produced by the energized coil 40 moves the plunger 42, which extends though the coil 40 and this the magnetic field, against the bias force of the return spring 48 in a direction away from the valve seat 44 so that the valve orifice 46 is open and pressurized fuel oil can travel from the inlet 26 to the outlet 30 via the valve orifice 46. When the coil 40 is again de-energized, the plunger 42 moves to seat against the valve seat 44 by the force of the return spring 48 to close the valve orifice 46 and prevent flow of pressurized fuel oil from the inlet 26 to the outlet 30. It is believed that a suitable electric solenoid valve 24 is available from Solenoid Solutions, Inc. of Erie, Pa.

The inlet 26 of the illustrated electric solenoid valve 24 is connected to the fuel supply system 28 to provide pressurized fuel oil to the inlet 26 of the electric solenoid valve 24. The illustrated fuel supply system 28 includes a fuel oil tank 50 and a fuel oil pump 52. Fuel oil is pulled from the fuel oil tank 50 through a first conduit 54 by the fuel oil pump 52 and pushed to the inlet 26 of the electric solenoid valve 24 through a second conduit 56 by the fuel oil pump 52. The fuel oil pump 52 is configured to produce a predetermined constant fuel oil pressure upstream of the electric solenoid valve 24 such as, for example, 100 to 150 psi. The illustrated fuel oil pump 52 is a positive displacement pump with a built-in pressure regulator. It is noted that the fuel oil tank 50 and the fuel oil pump 52 can be of any suitable type. It is also noted that the fuel supply system 28 can alternatively be of any other suitable type.

The electric solenoid valve 24 is controlled or driven by the electronic driver or controller 32 that is in electrical communication with the electric solenoid valve 24. The illustrated controller 32 includes a processor and memory and is configured to control the flow of fuel oil through the electric solenoid valve 24 and the nozzle 16 by changing or switching the electric solenoid valve 24 at a high frequency between its closed state and its open state by de-energizing and energizing the electric solenoid valve 24. The controller 32 can include a pulse width modulated drive to provide a pulse width modulated control signal to the electric solenoid valve 24 in the form of a square wave control signal at a predetermined frequency. The illustrated electronic driver or controller 32 can deliver “ON” or open state pulses for a plurality of preset periods of times such as, for example, 3 milliseconds to 100 milliseconds and can deliver “OFF” or closed state pulses for a plurality of preset periods of times 3 milliseconds to 100 milliseconds. The electronic driver or controller 32 can be of any suitable type. The period of times 36, 38 for the “ON” and “OFF” pulses are predetermined to obtain a desired fuel flow reduction or fuel savings while maintaining the self-sustaining flame 34 in the combustion chamber 22 with the pulsing flow of fuel oil without a constant ignition source igniting the pulses of fuel oil coming from the nozzle 16. That is, the flame 34 within the combustion chamber 22 is initially created by igniting the pulsing fuel flow with an igniter within the combustion chamber 22 such as, for example, a sparkplug, glow, plug and the like but once the flame 34 is created by the igniter, the flame 34 is maintained by the pulses of fuel oil from the nozzle 16 without further use of the igniter except when the fuel oil burners 12 is turned off and restarted.

The time period 36 the electric solenoid valve 24 is intermittently in the closed state is preferably in the range of 3 milliseconds to 7 milliseconds in order to maintain the self-sustaining flame 34. The time period 36 the electric solenoid valve 24 is intermittently in the closed state is preferably less than the time period 38 the electric solenoid valve 24 is intermittently in the open state and more preferably the electric solenoid valve 24 is intermittently in the closed state a time period 36 about 25% to about 75% of the time period 38 that the electric solenoid valve 24 is intermittently in the open state. As shown in FIG. 4, the control signal for the fuel oil flow through the illustrated electric solenoid valve 24 resembles a square wave control signal. The illustrated time period 36 that the electric solenoid valve 24 is intermittently in the closed state is 5 milliseconds and the illustrated time period 38 that the electric solenoid valve 24 is intermittently in the closed state is 50% of the time period 36 the electric solenoid valve 24 is intermittently in the open state (which in the illustrated embodiment is 10 milliseconds). The illustrated electric solenoid valve 24 is repeatedly in the open state for 10 milliseconds and then in the closed state for 5 milliseconds. Thus, the illustrated electric solenoid valve 24 is operated at 67 hertz (or cycles/second) at a 66% duty cycle to obtain a 33% reduction in fuel oil flow while producing substantially the same heat compared to a constant flow of the fuel oil under otherwise the same conditions. It is noted that any other suitable periods of time 36, 38 can alternatively be utilized.

FIG. 5 illustrates an alternative operation of the electric solenoid valve 24 wherein The illustrated electric solenoid valve 24 is repeatedly in the open state for 14 milliseconds and then in the closed state for 7 milliseconds. Thus, the illustrated electric solenoid valve 24 is operated at 48 hertz (or cycles/second) at a 66% duty cycle to obtain a 33% reduction in fuel oil flow while producing substantially the same heat compared to a constant flow of the fuel oil under otherwise the same conditions. This illustrated embodiment shows that the electric solenoid valve can 14 be intermittently closed and opened for other predetermined time periods 36, 38 and obtain fuel savings.

Any of the features or attributes of the above described embodiments and variations can be used in combination with any of the other features and attributes of the above described embodiments and variations as desired.

It is apparent from the above detailed description of preferred embodiments of the present invention, that the above-disclosed heating system has an economic and efficient oil burner that reduces fuel oil usage while producing an equivalent quantity of heat as prior art heating systems.

From the foregoing disclosure and detailed description of certain preferred embodiments, it is also apparent that various modifications, additions and other alternative embodiments are possible without departing from the true scope and spirit of the present invention. The embodiments discussed were chosen and described to provide the best illustration of the principles of the present invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the present invention as determined by the appended claims when interpreted in accordance with the benefit to which they are fairly, legally, and equitably entitled.

Claims

1. A fuel oil burner for a heating system, said fuel oil burner comprising, in combination: a nozzle having an inlet and outlet and configured to atomize fuel oil;an electric solenoid valve having an inlet for fluid-flow communication with a pressurized source of fuel oil and an outlet in fluid-flow communication with the inlet of the nozzle;wherein said electric solenoid valve is configured so that flow of fuel oil from the inlet of the electric solenoid valve to the inlet of the nozzle is prevented in a closed state of the electric solenoid valve and fuel oil flows from the inlet of the electric solenoid valve to the inlet of the nozzle in an open state of the electric solenoid valve;a controller in electrical communication with the electric solenoid valve and configured to intermittently change the valve between the closed state and the open state at predetermined time periods so that pulses of fuel oil exit the outlet of the nozzle; andwherein the electric solenoid valve is intermittently in the closed state a time period so that the pulses of fuel oil exiting the outlet of the nozzle self-sustain a flame.

2. The heating system according to claim 1, wherein the electric solenoid valve is in the closed state when deenergized and in the open state when energized.

3. The heating system according to claim 1, wherein the fuel oil entering the inlet of the nozzle is at constant pressure.

4. The heating system according to claim 1, wherein the pulses of fuel oil exiting the outlet of the nozzle self-sustain the flame without a constant ignition source.

5. The heating system according to claim 1, wherein the time period the electric solenoid valve is intermittently in the closed state is in the range of 3 microseconds to 7 microseconds.

6. The heating system according to claim 5, wherein the time period the electric solenoid valve is intermittently in the closed state is 5 microseconds.

7. The heating system according to claim 1, wherein the time period the electric solenoid valve is intermittently in the closed state is less than a time period the valve is intermittently in the open state.

8. The heating system according to claim 9, wherein the time period the electric solenoid valve is intermittently in the closed state is about 25% to 75% of the time period the valve is intermittently in the open state.

9. The heating system according to claim 8, wherein the time period the electric solenoid valve is intermittently in the closed state is about 50% of the time period the valve is intermittently in the open state.

10. A method for controlling and regulating flow of fuel oil in a heating system, said method comprising the steps of, in combination: obtaining a nozzle having an inlet and outlet and configured to atomize fuel oil;obtaining an electric solenoid valve having an inlet for fluid-flow communication with a pressurized source of fuel oil and an outlet in fluid-flow communication with the inlet of the nozzle;wherein said electric solenoid valve is configured so that flow of fuel oil from the inlet of the electric solenoid valve to the inlet of the nozzle is prevented in a closed state of the electric solenoid valve and fuel oil flows from the inlet of the electric solenoid valve to the inlet of the nozzle in an open state of the electric solenoid valve;intermittently changing the valve between the closed state and the open state at predetermined time periods so that pulses of fuel oil exit the outlet of the nozzle; andwherein the electric solenoid valve is intermittently in the closed state a time period so that the pulses of fuel oil exiting the outlet of the nozzle self-sustain a flame.

11. The heating system according to claim 10, wherein the electric solenoid valve is in the closed state when deenergized and in the open state when energized.

12. The heating system according to claim 10, wherein the fuel oil entering the inlet of the nozzle is at constant pressure.

13. The heating system according to claim 10, wherein the pulses of fuel oil exiting the outlet of the nozzle self-sustain the flame without a constant ignition source.

14. The heating system according to claim 10, wherein the time period the electric solenoid valve is intermittently in the closed state is in the range of 3 microseconds to 7 microseconds.

15. The heating system according to claim 14, wherein the time period the electric solenoid valve is intermittently in the closed state is 5 microseconds.

16. The heating system according to claim 10, wherein the time period the electric solenoid valve is intermittently in the closed state is less than a time period the valve is intermittently in the open state.

17. The heating system according to claim 16, wherein the time period the electric solenoid valve is intermittently in the closed state is about 25% to 75% of the time period the valve is intermittently in the open state.

18. The heating system according to claim 17, wherein the time period the electric solenoid valve is intermittently in the closed state is about 50% of the time period the valve is intermittently in the open state.

19. The heating system according to claim 10, wherein the valve is intermittently changed between the closed state and the open state with a controller in electrical communication with the electric solenoid valve.

20. A domestic furnace apparatus comprising, in combination: a combustion chambera nozzle having an inlet and outlet in communication with the combustion chamber and configured to atomize fuel oil;an electric solenoid valve having an inlet for fluid-flow communication with a pressurized source of fuel oil and an outlet in fluid-flow communication with the inlet of the nozzle;wherein said electric solenoid valve is configured so that flow of fuel oil from the inlet of the electric solenoid valve to the inlet of the nozzle is prevented in a closed state of the electric solenoid valve and fuel oil flows from the inlet of the electric solenoid valve to the inlet of the nozzle in an open state of the electric solenoid valve;a controller in electrical communication with the electric solenoid valve and configured to intermittently change the valve between the closed state and the open state at predetermined time periods so that pulses of fuel oil exit the outlet of the nozzle; andwherein the electric solenoid valve is intermittently in the closed state a time period so that the pulses of fuel oil exiting the outlet of the nozzle self-sustain a flame within the combustion chamber.