The present application relates generally to heaters. More particularly, the present application relates to dual-fuel heaters with a specialized valve configuration.
Heating units, such as fireplaces, are desirable features in the home. Devices that burn non-solid materials, such as gas, or that produce heat electrically have gradually gained popularity. Like wood, the combustion of gas can provide real flames and heat, but oftentimes entails a careful mixing of gas and air for desired or optimal performance. This aspect of the gas fireplace, and similar appliances, typically involves the delivery of air for combustion to an arrangement or device where the air is mixed with gaseous fuel, e.g., natural gas (NG) and liquid propane (LP). The air and fuel are mixed at a ratio for proper combustion and then delivered to a burner element or member, and ultimately provided to a combustion chamber of the fireplace or other similar appliance. The mixing of air and fuel is oftentimes accomplished in the burner itself.
It is also advantageous to have a unit that operates on different kinds of fuel. In many homes and other buildings, there may be NG or LP fuels available. Sellers may therefore ask for a unit that can be adapted for either NG or LP, depending on what source of gas is available, or desired for the installation. Accordingly, units that can be configured to operate with more than one fuel source have been developed and are well known. These are typically referred to as “dual-source” or “dual-fuel” units. For example, the burner element may include a valve system that, when in one position, allows the unit to operate with a first fuel, and when in a second position, allows the heating unit to operate with a second fuel. These dual-fuel units are typically set up so that a choice of fuel is made by the installer when the unit is first put into operation. While dual-fuel burner units have been in the art for decades, there is always a desire to make the units simpler and more reliable to use at a lower cost.
One problem in dual-fuel heaters is that the wrong fuel can be selected at the heater. For example, a user may select the NG fuel at the heater when the fuel provided to the heater is in fact LP. This can be a dangerous mistake because the NG orifice leading to the burner is larger than the LP orifice, and the LP gas is provided at a higher pressure than the NG gas. Accordingly, selecting the NG mode when using LP gas can provide an excessively high-pressure gas through a large orifice to a burner, causing a large flame and creating an obvious safety hazard.
The disclosed embodiments broadly include a dual-fuel heater having one or more oxygen depletion sensor (ODS) thermocouple pilots capable of maintaining the opening of a control valve that in turn allows the flow of fuel to the burner. In normal operating conditions, a primary fuel selector valve can be operated by a user to choose the fuel being used. In conventional dual-fuel heaters, fuel would flow from the fuel regulator directly to the control valve and then through a selector valve mechanism to the ODS thermocouple pilots and main burner. Instead, in the disclosed embodiments fuel would flow through a multi-port fuel selector system prior to reaching the control valve. This design is more reliable than conventional heater designs because it specifically directs the flow of the selected fuel while terminating the incorrect fuel even when the incorrect fuel is chosen rather than relying on pressure or electrical mechanisms and the ODS thermocouple pilots alone for safety measures. It also allows for safety mechanisms to be implemented upstream of the control valve for added simplicity and to avoid the wrong fuel from being supplied to the incorrect pilot.
For example, the present application can include a dual-fuel system having a first regulator adapted to provide a first fuel, a second regulator adapted to provide a second fuel, a control valve that receives fuel from either the first regulator or the second regulator, and a slave valve in fluid communication between the first and second regulators and the control valve. The slave valve can selectively permit a flow of the fuel to the control valve based on input of a user. The system can further include at least one thermocouple associated with a corresponding pilot, where the thermocouple provides an electrical signal to the control valve to control whether the control valve allows the passage of fuel through the control valve. Also included is a burner, where the electrical signal causes the control valve to allow the first or second fuel to flow to the burner.
Further disclosed is a valve system including a slave valve adapted to be positioned in fluid communication between first and second regulators and a control valve. The slave valve can selectively permit the flow of the fuel to the control valve based on input of a user. Also included is a primary fuel selector valve coupled to the slave valve and that receives the input from the user to correspondingly operate the slave valve based on the input.
Also disclosed is a dual-fuel system including means for providing a first fuel, means for providing a second fuel, means for controlling a flow of fuel from the means for providing a first fuel and means for providing a second fuel, means for selectively permitting a flow of the fuel to the means for controlling a flow of fuel based on input of a user, means for providing an electrical signal to the means for controlling a flow of fuel to control whether the means for controlling a flow of fuel allows a passage of fuel through the means for controlling a flow of fuel, and means for burning the fuel. The electrical signal causes the means for controlling a flow of fuel to allow the first or second fuel to flow to the means for burning the fuel.
For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated.
While this invention is susceptible of embodiments in many different forms, there is shown in the drawings, and will herein be described in detail, a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to embodiments illustrated. As used herein, the terms “present invention” and “disclosed embodiments” are not intended to limit the scope of the claimed invention and is instead a term used to discuss exemplary embodiments of the invention for explanatory purposes only.
The disclosed embodiments broadly include a dual-fuel heater having one or more ODS thermocouple pilots that operate a control valve. The control valve then controls whether fuel is distributed from a regulator to a burner based on the signal generated by the thermocouple(s). A primary fuel selector valve can be operated by a user to choose the fuel being used. The primary fuel selector valve provides fuel to the control valve upstream from the thermocouples, and is capable of blocking a passage of the fuel that is not chosen, either alone or with other mechanisms such as a slave valve. This allows for a simpler design that provides the fuel to the control valve prior to the thermocouples, and that further allows for upstream control mechanisms such as a slave valve, to control the flow of fuel to the control valve.
The control valve 120 includes, for example, a solenoid valve that opens or remains open upon the application of a predefined amount of current, for example, 200 milliamps. If the NG thermocouple 130 generates more than the requisite amount of current, the solenoid valve will open or remain open and allow fuel to be provided to a burner 135. If the NG thermocouple 130 does not provide sufficient current or another sufficient signal, the solenoid valve will close and will no longer provide fuel to the burner 135. In some embodiments, the solenoid valve is coupled to a thermal switch, where the thermal switch will instantaneously close the solenoid valve upon the thermal switch reaching a specific minimum allowed temperature. These safety mechanisms are implemented in heaters to protect against the pilot flame going out or not combusting sufficient fuel, in which case the flammable fuel will be emitted into the surrounding home or other structure and cause a gas leak. The solenoid valve blocks such a leak from occurring by closing off supply of the fuel when the fuel is not properly combusted.
The fourth passage 115d is closed in the illustration shown in
As shown in
The second embodiment 200 is similar to the system 100 described above, but includes two passages 115c, d located on a side of the slave valve 115, and orifices 152, 153 leading to the burner 135 in a parallel or side-by-side configuration. The slave valve 115 and primary fuel selector valve 133 can also be coupled together by a coupling 170, or in some embodiments, can be integral with one another. As shown in
The invention has been discussed herein as being a dual-fuel system for NG and LP fuel. However, the invention is not so limited to the disclosed fuels, and can be implemented with any fuel without departing from the spirit and scope of the present application.
As discussed herein, the term “coupled” is intended to refer to any connection, direct or indirect, and is not limited to a direct connection between two or more elements of the disclosed invention. Similarly, “operatively coupled” is not intended to mean any direct connection, physical or otherwise, and is merely intended to define an arrangement where two or more elements communicate through some operative means (e.g., through conductive or convective heat transfer, or otherwise). The term “coupled” can mean, in some embodiments, two objects being integral with one another.
The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of the inventors' contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.
Number | Name | Date | Kind |
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20080223465 | Deng | Sep 2008 | A1 |
20140272741 | Downing | Sep 2014 | A1 |
Number | Date | Country | |
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20180058692 A1 | Mar 2018 | US |
Number | Date | Country | |
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62379409 | Aug 2016 | US |