Waste oil burner improved preheater design

Abstract

An improved oil preheater assembly for a waste oil burner that significantly reduces the labor time required to perform routine maintenance. This is accomplished by incorporating a removable cover to directly access the heated oil passages for cleaning thereby providing a simplified method of access to the areas most often requiring routine maintenance. Additionally this design provides an improved electrical control system which significantly reduces electrical energy consumption and the formation of oil carbonization when oil burner heat output is not required. Additionally this design incorporates a nozzle cleaning system for a low pressure siphoning type of discharge nozzle which can remove carbonization and other nozzle contamination and obstructions without the disassembly of components.

Claims

1. An electrical control system for providing on-demand heat to a waste oil burner preheater block having a heating element in operational association with the block and an internal winding passageway for delivering oil, the system comprising: (a) means for receiving from a user a desired minimum preheater block temperature for oil burner ignition; (b) means for receiving a first trigger signal for heat; (c) transmitting means for powering the heating element associated with the preheater block in response to the signal; (d) means for monitoring the temperature of the preheater block; (e) transmitting means for powering ignition of the oil burner when the preheater block has reached the desired temperature; (f) means for receiving a second trigger signal that the call for heat has been satisfied, and (g) transmitting means for terminating power to the heating element, such that the preheater block can cool to an ambient temperature.

2. The electrical control system of claim 1 wherein the preheater block temperature monitoring means comprises a temperature sensor in operational association with the preheater block.

3. The electrical control system of claim 1 wherein the means for receiving a desired minimum preheater temperature block temperature comprises a programmable digital temperature controller.

4. The electrical control system of claim 1 wherein the first trigger signal is from an ambient thermostat or boiler aquastat.

5. The electrical control system of claim 1 wherein the second trigger signal is from an ambient thermostat or boiler aquastat.

6. The electrical control system of claim 1 wherein the heating element can produce more than about 300 watts.

7. The electrical control system of claim 1 further comprising transmitting means for directing the delivery of compressed gas to the preheater block on demand.

8. A method for providing on-demand heat to an oil burner preheater block, the method comprising the steps of: (a) an electrical control system receiving from a user a desired minimum preheater block temperature for oil burner ignition, the control system being in operational association with a temperature sensor and a heating element in operational association with the preheater block; (b) the electrical control system receiving a first trigger signal for heat; (c) the electrical control system transmitting power to the heating element in response to the first trigger signal; (d) the electrical control system receiving temperature data from the temperature sensor; (e) the electrical control system transmitting power for igniting the oil burner when the preheater block has reached the desired minimum temperature; and (f) the electrical control system terminating power to the heating element in response to a second trigger signal that the call for heat has been satisfied.

9. The method of claim 8 wherein the first and second trigger signals occur sequentially.

10. The method of claim 8 wherein the first trigger signal is from an ambient thermostat or boiler aquastat.

11. The method of claim 8 wherein the second trigger signal is from an ambient thermostat or boiler aquastat.

12. The method of claim 8 wherein a programmable digital temperature controller receives the desired minimum preheater block temperature.

13. The method of claim 8 wherein the heating element can produce more than about 300 watts.

14. The method of claim 8 comprising the additional step of directing the delivery of compressed gas to the preheater block on demand.

15. The method of claim 14 wherein the delivery of compressed gas occurs prior to igniting the oil burner.

16. The method of claim 8 wherein the electrical control system consumes less than about 5 watts of power in the absence of the first trigger signal.

17. A method for reducing oil carbonization forming in an oil burner preheater block, the method comprising the steps of: an electrical control system receiving from a user a desired minimum preheater block temperature for oil burner ignition, the control system being in operational association with a temperature sensor and a heating element in operational association with the preheater block; the electrical control system receiving a first trigger signal for heat; the electrical control system transmitting power to the heating element in response to the first trigger signal; the electrical control system receiving temperature data from the temperature sensor; the electrical control system transmitting power for igniting the oil burner when the preheater block has reached the desired minimum temperature; and the electrical control system terminating power to the heating element in response to a second trigger signal that the call for heat has been satisfied.

18. The method of claim 17 wherein a programmable digital temperature controller receives the desired minimum preheater block temperature.

19. The method of claim 17 comprising the additional step of directing the delivery of compressed gas to the preheater block on demand.

20. The method of claim 17 wherein at least one of the trigger signals is from an ambient thermostat or boiler aquastat.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A more complete understanding of the present invention may be had from the following detailed description, particularly when considered in light of the accompanying drawings, wherein:

(2) FIG. 1 is a schematic view of a waste oil preheater block with a removable cover to access oil passages for cleaning.

(3) FIG. 2 is a schematic rear view of an oil burner gun modified with the addition of an electrical control box to house the electrical components required for control of the preheater block heating system.

(4) FIG. 3 is a schematic side view of an oil burner gun.

(5) FIG. 4 is a schematic side view of an oil burner gun with the blast tube removed showing the preheater block equipped with a removable cover plate.

(6) FIG. 5 is a simplified block wiring schematic detailing the improved electrical control system design which reduces electrical energy consumption.

DETAILED DESCRIPTION OF THE DRAWINGS

(7) As noted above, this invention relates to waste oil burners. In particular, this invention relates to an improved preheater system for waste oil burners which minimizes the time required for routine cleaning maintenance of preheater waste oil fuel supply passages, significantly reduces the electrical consumption of the heating circuit during standby periods (or periods where no demand for burner gun heat output exist), and provides a method for cleaning a low pressure siphoning type of discharge nozzle without nozzle removal.

(8) Referring now to FIG. 1, there is shown a waste oil burner preheater block 13 with a removable cover plate 20 for access to cleaning the block passages 17, which are heated by a cartridge type heater element 19, through which the waste oil fuel flows and is heated non-directly by the heater element 19 prior to discharge from the nozzle 11. To prevent leakage of the waste oil fuel the removable cover plate 20 is sealed to the block with a suitable material. A groove 21 may be incorporated into the block 13 and/or the cover plate 20 to hold a suitable sealing material. In standby (or no demand for heat modes) the preheater block 13 is not electrically heated and remains at ambient temperature. When a demand for heat is present the preheater block 13 electrical heating circuits energize the heating element 19 and the preheater block 13 is quickly brought up to a temperature to achieve atomization of the waste oil fuel during discharge from the nozzle 11 required for proper combustion. Approximately two minutes is required to increase the block 13 temperature from room temperature to 160 degrees Fahrenheit. The waste oil fuel to be heated enters at location 16, is heated as it travels through passage 17, enters the nozzle at location 18, and is atomized as it mixes with compressed air during discharge from the nozzle 11. The compressed air for atomization enters the rear of the preheater block 13 at location 22 where it travels through the block to location 15 to enter the nozzle 11 prior to the discharge port. The mixture is ignited with a spark producing transformer and electrodes (not shown). To clean a clogged nozzle compressed air is briefly re-routed using a solenoid valve (indicated by item 27 on FIG. 5) and/or check valve system and piping (not shown) to enter the oil passage as close to location 18 as possible. Waste oil fuel pressure within the heated passageways normally does not exceed 10 psi. This brief introduction of air pressure supplied at pressures up to 175 psi will clear nozzle clogs without the need to physically remove the nozzle and clean it. Further more detailed description of these components and their function is not required as those who are skilled in the art of designing and manufacturing waste oil burners are familiar and knowledgeable about them.

(9) Referring now to FIG. 2, there is shown a rear view of a typical fuel oil burner assembly. Pictured are the following components; combustion air motor 1, a primary or safety controller 4, an ignition transformer 5, fuel oil burner housing 6. Further more detailed description of these components and their function is not required as those who are skilled in the art of designing and manufacturing waste oil burners are familiar and knowledgeable about them. Fuel oil burner assemblies of this type are recognized by those skilled in the art as that which are typically modified by waste oil burner manufacturers in order to use waste oil as a fuel. Fuel oil burner assemblies of this type when used with the present invention can be used to burn waste oil as a fuel. FIG. 2 shows such a fuel oil burner which has been modified with the addition of a box 2 in which to house the additional electrical components required for the operation of the preheater block electrical circuits. Item 3 refers to one possible location of the digital temperature controller used in the present invention to maintain the preheater block temperature at the desired temperature when a demand for heat is called for by the system thermostat or aqua-stat (indicated by item 35 on FIG. 5).

(10) Referring now to FIG. 3, there is shown a side view of a typical fuel oil burner assembly. Pictured are the following components; combustion air motor 1, a primary or safety controller 4, an ignition transformer 5, a blast or combustion air delivery tube 7, a mounting flange for mounting a burner to a furnace or boiler 8. Item 2 refers to a box which has been added on to the standard fuel oil burner in which to house the additional electrical components required for the operation of the preheater block electrical circuits.

(11) Referring now to FIG. 4, there is shown a side view of a converted for waste oil use fuel oil burner assembly which has been partially disassembled for access to the preheater block 13 of the present invention. Pictured are the following components; 7 blast or combustion air delivery tube, 8 mounting flange for mounting burner to furnace or boiler, 9A, 9B, and 9C screws used to retain the blast tube 7 onto the fuel oil burner housing (item 6 of FIG. 2), electrodes 10 used to transfer spark from transformer (see item 5 of FIGS. 2) to 11 the nozzle discharge ignition area, the flame retention head or combustion air turbulator 12, and the waste oil fuel preheater block 13 of the present invention.

(12) Referring now to FIG. 5, there is shown a simplified block wiring schematic of the present invention detailing the improved electrical control system design which reduces electrical energy consumption during standby periods where no heat output from the burner is required. Room thermostat or boiler aquastat 35 provides a demand for heat signal to turn burner heating and control circuits on. Power control relay 33 is used to provide power to cartridge heater element 19 and primary safety controller 4 when a call for heat has been recognized by the thermostat or aquastat 35. Pictured are the following components; primary safety controller 4 used to provide power to oil solenoid 26 and primary compressed air solenoid 28, ignition transformer 5, combustion air motor 1, and hour meter 30, only when a call for heat has been recognized by the thermostat or aquastat 35. The cad cell flame sensor 24 is monitored by the primary controller 4 to shut down the burner should a flame failure occur. Ignition transformer 5 provides a spark to ignite the waste oil fuel and air mixture. Primary compressed air solenoid 28 controls the flow of atomization air at the nozzle. Secondary compressed air solenoid 27 is used during the air pressure nozzle cleaning process operated by switch 36. Oil solenoid 26 is used for control of waste oil fuel flow into the preheater block. Oil solenoid 26 may also be used during the air pressure nozzle cleaning process to limit the direction of air pressure flow through the nozzle. A mechanical one-way check valve could be substituted for this purpose. Motor 1 provides combustion air, hour meter 30 records accumulated burner on time, and thermocouple type temp sensor 31 attached to the preheater block (see FIG. 4 item 13) provides a preheater block temperature signal to the digital temperature controller 3. Digital temperature controller 3 is a programmable electronic control device which will maintain preheater block 13 temperature at a pre-determined point when a call for heat has been recognized by the thermostat or aquastat 35. Further more detailed description of these components and their function is not required as those who are skilled in the art of designing and manufacturing waste oil burners are familiar and knowledgeable about them.