GB2515253A

GB2515253A - Oil burner system

Info

Publication number: GB2515253A
Application number: GB1305468.9A
Authority: GB
Inventors: Martin Graham Rowlingson
Original assignee: Henry Martin & Sons Ltd
Current assignee: Henry Martin & Sons Ltd
Priority date: 2013-03-26
Filing date: 2013-03-26
Publication date: 2014-12-24
Also published as: GB201305468D0

Abstract

An oil burner system 10 and method of supplying heated oil to a burner 49 assembly comprising an oil vessel 12 having an oil heating arrangement 22; a supply arrangement for the transfer of heated oil from the oil vessel to a burner assembly, the supply arrangement comprises a circulation path 29 in fluid communication with the oil vessel for the circulation of heated oil from the vessel and back and a transfer path 40 in fluid communication with the circulation path for the selective transfer of heated oil from the circulation path to the burner assembly; an oil pump 34 is provided for the circulation and transfer of heated oil; and a control means 15 is configured to regulate the supply of heated oil from the circulation path 29 to the burner assembly 49. Another aspect of the invention is a conversion kit for converting an oil burner to burn recycled vegetable oil, this kit comprises the same features as above but with the oil vessel 12 having an inlet for introduction of oil from a supply 11. The conversion kit maybe configured to interact with existing oil burner control mechanisms. The system may include an auxiliary heater 43.

Description

OIL BURNER SYSTEM

This invention relates to an oil burner system and to a method of supplying heated oil to a burner assembly. The invention also extends to a conversion kit for converting an oil burner to burn recycled oil. The system and method have been designed principally for use with viscous "biomass" oil, such as vegetable oil and the invention will be described with particular emphasis on this use. It will be appreciated though that the invention is not limited to such use and other types of oil may equally be used.

Oil burners are used to provide heating to dwellings and buildings. Such burners use oil as a fuel source and operate by atomising the oil into a fine spray by forcing it through a nozzle at high pressure and then ignited. An electric fan is provided to force air through the system. In terms of environmental sustainability and economy it is highly advantageous to use recycled "biomass" oil, such as recycled vegetable oil as a fuel source for oil burners. Generally, vegetable oil is not suitable for conventional oil burners because it has a high viscosity. To reduce the viscosity, high viscous oils must be pre-heated. Systems have been developed which allow oil burners to operate using high viscous oils by incorporating a preheater between an oil reservoir and the burner. However, in the majority of cases the efficiency of such systems is not ideal because the heated oil inevitably cools as it travels from the pre-heater to the burner. Furthermore, because an oil burner is not usually in constant use, when the oil burner is not initiated, oil remains in the conduit between the pre-heater and burner. Thus, upon further initiation of the oil burner, the oil initially provided to the burner is cool, highly viscous and generally unsuitable.

It is a principle aim of the present invention to provide an oil burner system, a method for supplying heated oil to a burner and a conversion kit for use with a conventional oil burner which addresses some or all of the above problems.

According to one aspect of this invention, there is provided an oil burner system comprising: -an oil vessel having a heating arrangement for heating oil therein; -a supply arrangement for the transfer of heated oil from the oil vessel to a burner assembly, the supply arrangement comprising: -a circulation path in fluid communication with the oil vessel for the circulation of heated oil from the oil vessel and back thereto; -a transfer path in fluid communication with the circulation path for the selective transfer of heated oil from the circulation path to the burner assembly; and -an oil pump for the circulation and transfer of heated oil; and -control means configured to regulate the supply of heated oil from the circulation path to the burner assembly.

According to another but closely related aspect of this invention, there is provided a method of supplying heated oil to a burner comprising the steps of: heating oil within a vessel; circulating heated oil from the oil vessel around a circulation path; and selectively transferring heated oil from the circulation path to the transfer path leading to a burner assembly.

In this arrangement heated oil may be circulated continuously round the circulation path so that when burner start-up initiated, the required amount of heated oil may be directed through the transfer path to the burner assembly. By diverting oil from the circulation path to the burner assembly when required the oil is already pre-heated to the necessary temperature to effect low viscous fluid flow and may be diverted to travel a small distance along the transfer path to the burner.

Oil is likely to remain in the transfer path between the end of one operation of the burner assembly and initiation of the next. Such oil will inevitably cool and become more viscous. To improve efficiency of the system it is preferable that the transfer path includes an auxiliary heater arranged further to heat oil within the transfer path. This ensures that heated oil will be delivered to the burner assembly at start up.

To ensure that heated oil in the system reaches the most appropriate temperature and pressure for optimum burning, the control means may include one or more sensors to monitor the temperature and/or pressure oil in the circulation path and/or the transfer path. In this arrangement, the system may include one or more valve in the supply arrangement, the one or more valve being operated by the control means. In this way, the control means may be configured to operate the valves, to supply heated oil to the transfer path from the circulating path, when the temperature and/or pressure of heated oil exceeds a pre-determined threshold. Operation of an oil burner is usually initiated by a user-operated actuator (I.e. a button) or a timer operatively connected to the burner assembly. Preferably, the control means is arranged to intercept initiation signals from the burner assembly and to operate the supply arrangement in response to said signals.

Preferably, the control means includes an electronic programmable circuit. By being programmable, the operator or installer may program the control means to regulate the supply of heated oil to the burner assembly only when certain conditions have been met, e.g. when the heated oil has reached a pre-determined threshold. The temperature and/or pressure threshold may be different depending on the overall set up of the system but in order to achieve a clean burn the heated oil should reach the firing nozzle at a minimum temperature of approximately 110 degrees Celsius and at a pressure of 25 Bar.

Preferably, the threshold temperature is within the range of approximately 110 to 120 degrees Celsius. Even more preferably, the control means is configured to supply heated oil to the burner assembly at a temperature of approximately degrees Celsius and a pressure of 25 Bar.

The oil to be burned is pre-heated in the oil vessel. To achieve this, the heating arrangement may comprise an electrically heated resistive element, such as an immersion heater. Preferably, the heating arrangement is arranged to pre-heat oil from an initial temperature of approximately 20 degrees Celsius to a temperature of around between 130 to 140 degrees Celsius. Such heating of the oil ensures that any micro particles of moisture within the oil cavitate to steam. Preferably, thermostats or other temperature sensors are provided in the oil vessel to control and limit the temperature of the oil therein.

The circulation path preferably includes circulation feed and return conduits for the circulation of heated oil from the oil vessel and back thereto. In practice, such feed and return conduits may form a continuous loop to and from the oil vessel. The transfer path may comprise a transfer feed conduit in fluid communication with the circulation path to allow the supply of heated oil from the circulation path to the burner assembly. The pipes of the transfer path and circulation path may be thermally insulated as may be the oil vessel.

Preferably, the burner system is specifically configured for burning viscous oil, such as vegetable based oil. The oil to be burned by the burner system may be recycled vegetable oil, which is highly beneficial economically and environmentally.

In a further aspect of this invention, there is provided a conversion kit for converting an oil burner to burn recycled vegetable oil, the conversion kit comprising: -a vessel having an inlet for the introduction of oil from a supply and a heating arrangement for heating oil therein; -a supply arrangement comprising: a circulation path adapted for fluid communication with the vessel for the circulation of heated oil from the vessel and back thereto; a transfer path selectively in fluid communication with the circulation path and adapted for fluid communication with a burner assembly; and an oil pump for circulating and transferring heated oil; and -control means configured to control and regulate operation of the supply arrangement to supply heated oil to a burner assembly, as required.

The conversion kit is designed for use with existing oil burners which are not suitable for the burning of viscous fluids. This is achieved in part by pre-heating the oil in the vessel and also by circulating the heated oil continuously round the circulation path so that when burner start-up is initiated, oil at the required temperature may be directed through the transfer path to the burner assembly at the required temperature and pressure.

Preferably, the control means is configured to interact with the existing control mechanism of the oil burner so that operation of the supply arrangement will be initiated when required.

The conversion kit may include an auxiliary heater in the transfer path arranged further to heat oil therein, as hereinbefore described with reference to the oil burner system. One or more sensors may also be provided in order to monitor the temperature and/or pressure of oil in the circulation path and/or transfer path. In this arrangement the conversion kit may further comprise one or more valves in the supply arrangement, the one or more valves being operated by the control means depending on the temperature and/or pressure monitored by the sensors. The temperature and/or pressure thresholds and settings vary depending on the type of oil burner to be converted and the characteristics of the oil to be burnt.

By way of example only, one specific embodiment of oil burner system of this invention will now be described in detail, reference being made to the accompanying drawing in which:-Figure 1 is a simplified diagrammatic view of a system arranged to produce heat by combusting recycled vegetable oil and which operates in accordance with this invention.

Referring to Figure 1, there is shown in simplified diagrammatic form an oil burner system 10. The system 10 includes an oil storage tank 11 which is in fluid communication with an oil vessel 12 by way of an oil entry conduit 13. An oil inlet sensor 14 is provided within the oil entry conduit 13 for detecting the temperature of oil travelling from the storage tank 11 to the oil vessel 12. A connection (not shown) is provided between the oil inlet sensor 14 and a controller 15 so that the temperature information can be provided to the controller 15. A lockable valve 18 is provided along the oil entry conduit 13 selectively to prevent the flow of oil into the oil vessel 12. A fire solenoid valve 19 is also provided along the oil entry conduit 13 and is configured automatically to close when a tire is detected to prevent the flow of oil into the oil vessel 12.

The oil vessel 12 contains an immersion heater 22 and has a vent 23 which extends above the level of the storage tank 11 for the release of moisture within the oil. An oil storage sensor 24 is provided in the oil vessel 12 to detect oil temperature and this sensor 24 is connected to the controller 15 to relay the temperature information thereto. A control thermostat 25 and a level limit sensor 26 are positioned on the oil vessel 12 and these control the sored oil temperature.

A circulation path 29 extends from the oil vessel 12 and back thereto and is defined by teed conduit 30 and return conduit 31, thus forming a fluid loop.

Valves 32, 33 are provided in the circulation path to control the flow of oil from the oil vessel 12 and back thereto. The feed conduit 30 includes a pump 34 to drive oil flow and an oil flow sensor 35 is provided after the pump 34 to detect the oil flow temperature. A high temperature oil filter 39 is provided before the pump 34 so as to protect the interior of the pump 34. A further path 36 is provided from the pump 34 back to the oil vessel 12 and this includes a valve 37 so that the pressure of the pump 34 may be controlled. A further oil return sensor 38 is located within the return conduit 31 to detect the temperature of oil returning to the oil vessel 12. Each of the sensors 35, 38 is connected to the controller 15.

A transfer path 40 is provided between the feed 30 and return 31 conduits and the flow of oil into the transfer path 40 is controlled by a first solenoid valve 41 in the transfer path 40. A second solenoid valve 42 is provided in the circulation path 29 to control the flow of oil through the return conduit 31. Each of these valves 41, 42 is operably connected to the controller 15. The transfer path 40 includes an auxiliary heater 43 therearound and further sensors 44, 45 to detect the oil temperature and pressure. The transfer path 40 leads to an oil burner nozzle 46.

The transfer path 40 is connected to a burner assembly 49 for the transfer of heated oil. A sensor 50 is provided on the burner assembly 49 to detect combustion carbon dioxide levels and a fire sensor 51 is also provided, which is also connected to the controller 15. The controller 15 is arranged to receive signals from the burner assembly 49 and is electronically programmable so that the valves are operably dependent upon pre-set temperature and pressure thresholds.

Operation of the system as hereinbefore described will now be discussed.

The system 10 is particularly useful for the burning of new or recycled vegetable oil which has been pre-filtered down to 5 microns. The oil is stored in the storage tank 11 and is transferred to the oil vessel 12 when required. On travelling to the oil vessel 12 the sensor 14 detects the oil inlet temperature and provides this information to the controller 15. The oil entering the vessel 12 will usually be approximately 20 degrees Celsius. Oil within the oil vessel 12 is heated by the immersion heater 22 to a temperature of around 140 degrees Celsius. Any micro particles of moisture within the oil cavitate to steam and vent off through the vent 23 above the storage tank 11 maximum storage level.

The high pressure, high temperature pump 34 activates on a run command from the burner assembly 49 and circulates heated oil from the oil vessel 12 round the circulation path 29. When the oil return sensor 38 detects a temperature of approximately 110 degrees Celsius the controller 15 instructs the burner assembly 49 to start a pre-purge and ignition cycle. The controller detects the ignition cycle from the burner assembly 49 and operates the first solenoid valve 41 in the transfer path 40 to open and simultaneously regulates the second solenoid valve 42 in the circulation path 29 to close at least partially so as to allow the appropriate pressure to be sustained at the supply nozzle 46 but to still allow sufficient return circulation of oil back to the oil vessel 12 to sustain adequate temperature of the oil within the circulation path 29.

The controller 15 reads the temperatures and pressures around the system 10 and operates the valves accordingly so as to achieve the correct control sequence.

If a fault occurs, the system 10 is designed to shut down. The immersion heater 22 in the oil vessel 12 will shut down if excessive temperature is detected or the fire valve 19 is activated.

Claims

CLAIMS1. An oil burner system comprising: -an oil vessel having a heating arrangement for heating oil therein; -a supply arrangement for the transfer of heated oil from the oil vessel to a burner assembly, the supply arrangement comprising: -a circulation path in fluid communication with the oil vessel for the circulation of heated oil from the oil vessel and back thereto; -a transfer path in fluid communication with the circulation path for the selective transfer of heated oil from the circulation path to the burner assembly; and -an oil pump for the circulation and transfer of heated oil; and -control means configured to regulate the supply of heated oil from the circulation path to the burner assembly.
2. An oil burner system as claimed in claim 1, wherein the transfer path includes an auxiliary heater arranged further to heat oil within the transfer path.
3. An oil burner system as claimed in claim 1 or claim 2, wherein the control means includes one or more sensors to monitor the temperature and/or pressure of oil in the circulation path and/or transfer path.
4. An oil burner system as claimed in claim 3, further comprising one or more valves in the supply arrangement, the one or more valves being operated by the control means.
5. An oil burner system as claimed in any of the preceding claims, wherein the control means includes an electronic programmable circuit.
6. An oil burner system as claimed in any of the preceding claims wherein the control means is configured to supply heated oil at a temperature of 120 degrees Celsius and a pressure of 25 Bar.
7. An oil burner system as claimed in any of the preceding claims, wherein the heating arrangement comprises an electrically heated resistive element.
8. An oil burner system as claimed in any of the preceding claims, wherein the circulation path includes circulation feed and return conduits for the circulation of heated oil from the oil vessel and back thereto.
9. An oil burner system as claimed in claim 7, wherein the transfer path includes a transfer feed conduit in fluid communication with the circulation path.
10. An oil burner system as claimed in any of the preceding claim, configured for burning viscous oil.
11. An oil burner system as claimed in claim 10, configured for burning recycled vegetable based oil.
12. An oil burner system as claimed in claim 1 and substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.
13. A method of supplying heated oil to a burner assembly comprising the steps of: heating oil within an oil vessel; circulating heated oil from the oil vessel around a circulation path; and selectively transferring heated oil from the circulation path to a transfer path leading to a burner assembly.
14. A method as claimed in claim 13, wherein heated oil transferred to the transfer path is further heated by an auxiliary heater in the transfer path.
15. A method as claimed in claim 13 or claim 14, wherein the temperature and/or pressure of heated oil in the supply arrangement is monitored by sensors.
16. A method as claimed in claim 15, wherein the supply of heated oil to the transfer path from the circulating path is regulated by control means configured to operate valves when the temperature and/or pressure of heated oil exceeds a pre-determined threshold.
17. A method as claimed in claim 16, wherein the temperature threshold is degrees Celsius and the pressure threshold is 25 Bar.
18. A method as claimed in any of claims 13 to 17, wherein the control means is arranged to intercept signals from the burner assembly and to operate the supply arrangement in response to said signals.
19. A method as claimed in any of claims 13 to 18, wherein the oil to be heated in the oil vessel is a viscous oil.
20. A method as claimed in claim 19, wherein the oil to be heated in the oil vessel is a recycled vegetable based oil.
21. A conversion kit for converting an oil burner to burn recycled vegetable oil, the conversion kit comprising: -a vessel having an inlet for the introduction of oil from a supply and a heating arrangement for heating oil therein; -a supply arrangement comprising: a circulation path adapted for fluid communication with the vessel for the circulation of heated oil from the vessel and back thereto; a transfer path selectively in fluid communication with the circulation path and adapted for fluid communication with a burner assembly; and an oil pump for circulating and transferring heated oil; and -control means configured to control and regulate operation of the supply arrangement to supply heated oil to a burner assembly, as required.
22. A conversion kit as claimed in claim 21, wherein the control means is configured to interact with the existing control mechanism of the oil burner.
23. A conversion kit as claimed in claim 21 or claim 22, further comprising an auxiliary heater in the transfer path arranged to heat oil therein.
24. A conversion kit as claimed in any of claims 21 to 23, further comprising one or more sensors to monitor the temperature and/or pressure of oil in the circulation path and/or transfer path.
25. A conversion kit as claimed in claim 24, further comprising one or more valves in the supply arrangement, the one or more valves being operated by the control means depending on the temperature andlor pressure monitored by the sensors.