Patent Application
20130040252
The present disclosure generally relates to gas fired heating appliances such as water heaters, and more particularly to monitoring a pilot burner flame of such heating appliances.
This section provides background information related to the present disclosure which is not necessarily prior art.
Gas fired heating units such as gas water heater appliances typically comprise a gas valve for supplying gas to a main burner and a standing pilot burner within a burner chamber. Since water heaters now have sealed burner chambers, manual lighting of the standing pilot burner with a match is not possible. Accordingly, the gas valve has a manually-opened pilot valve that must be depressed and held open while an ignition device is activated to establish a pilot flame at the standing pilot burner. Once the pilot valve is manually opened and a pilot flame is established at the standing pilot burner, the pilot burner burns gas continuously to thereby provide an ignition source for the main burner. These gas valves and standing pilot burners operate independently of any connection to electrical power within the residential or commercial building. However, it is difficult for users to operate the pilot valve and ignition device and monitor the pilot burner flame.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
Various embodiments of an apparatus are provided for indicating the level of pilot flame output and when flame output is sufficient to cause a thermocouple to generate a voltage that will hold a pilot valve open. One embodiment of an apparatus includes a voltage measuring circuit having first and second connectors configured to be coupled to a thermocouple that generates a voltage in response to a gas pilot flame supplied by a gas valve. The voltage measuring circuit is configured to provide an output indicative of a magnitude of the voltage generated by the thermocouple. The apparatus includes a light emitting device and a controller coupled to the voltage measuring circuit and the light emitting device. The controller is configured to controllably switch the light emitting device on and off in a flashing manner at a frequency based on the output indicative of the magnitude of the voltage of the thermocouple, to thereby generate a flash rate corresponding to the magnitude of the voltage generated by the thermocouple. The flash rate increases as the magnitude of the voltage increases, to thereby provide an indication of when the voltage magnitude is sufficient to cause a valve operator to hold the gas valve open.
According to another aspect of the present disclosure, a system is provided for indicating the level of pilot flame output in a gas appliance having a manually opened gas valve. The system includes a gas valve having a manually-opened pilot valve that is held in an open position when a sufficient voltage is applied to a valve operator, and a thermocouple that converts heat from a gas pilot flame into a voltage that is applied to the valve operator. The system includes a voltage measuring circuit configured to provide an output indicative of a magnitude of the voltage generated by the thermocouple, and a light emitting device. A controller is coupled to the voltage measuring circuit and the light emitting device. The controller comprises a microprocessor that is configured to establish, based on the output indicative of the magnitude of the voltage generated by the thermocouple, a switch sequence for switching the light emitting device on and off in a flashing manner to thereby generate a flash rate corresponding to the magnitude of the voltage generated by the thermocouple. The flash rate increases as the voltage increases to provide an indication of when the magnitude of the voltage is sufficient to cause the valve operator to hold the gas valve open, where the manually-opened pilot valve must be held down until the voltage generated by the thermocouple is sufficient to hold the pilot valve open.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
According to one aspect of the present disclosure, various embodiments of an apparatus are provided for indicating when the level of pilot flame output is sufficient to cause a thermocouple to generate a voltage that will hold a pilot valve open. The apparatus includes a voltage measuring circuit having first and second connectors configured to be coupled to a thermocouple that generates a voltage in response to a gas pilot flame supplied by a gas valve. The voltage measuring circuit is configured to provide an output indicative of a magnitude of the voltage generated by the thermocouple. The apparatus includes a light emitting device and a controller coupled to the voltage measuring circuit and the light emitting device. The controller is configured to controllably switch the light emitting device on and off in a flashing manner at a frequency based on the output indicative of the magnitude of the voltage of the thermocouple, to thereby generate a flash rate corresponding to the magnitude of the voltage generated by the thermocouple. The flash rate increases as the magnitude of the voltage increases, to provide an indication of when the voltage magnitude is sufficient to cause a valve operator to hold the gas valve open.
According to another aspect of the present disclosure, a system is provided for indicating the level of pilot flame output in a gas appliance having a manually opened gas valve. The system includes a gas valve having a manually-opened pilot valve that is held in an open position when a sufficient voltage is applied to a valve operator, and a thermocouple that converts heat from a gas pilot flame into a voltage that is applied to the valve operator. The system includes a voltage measuring circuit configured to provide an output indicative of a magnitude of the voltage generated by the thermocouple, and a light emitting device. A controller is coupled to the voltage measuring circuit and the light emitting device. The controller comprises a microprocessor that is configured to establish, based on the output indicative of the magnitude of the voltage generated by the thermocouple, a switch sequence for switching the light emitting device on and off in a flashing manner to generate a flash rate corresponding to the magnitude of the voltage generated by the thermocouple. The flash rate increases as the voltage increases to provide an indication of when the magnitude is sufficient to cause the valve operator to hold the gas valve open, where the manually-opened pilot valve must be held down until the voltage generated by the thermocouple is sufficient to hold the pilot valve open.
Referring to
The voltage measuring circuit 110 is configured to receive via the first and second connectors 101, 102 an input of a voltage generated by a thermocouple, and to provide an output that is indicative of the magnitude of the voltage. The voltage measuring circuit 110 may comprise, for example, an op-amp 112 (U2) configured as a differential amplifier that is used to determine the difference of two voltage inputs, multiplied by a constant. The negative (−) and positive (+) voltage outputs from a thermocouple are connected to the first and second connectors 101, 102. The thermocouple's positive (+) voltage V2 is connected to the second connector 102 and applied across a resistor R5 and input to a non-inverting (+) pin of the op-amp 112, and the negative (−) voltage V1 is connected to the first connector 101 and applied across a resistor R4 and input to an inverting (−) pin of the op-amp 112, where the resistance of R4 equals R5. The measuring circuit 110 may include a compensating capacitor C2 in parallel with resistor R3. The amplification or gain is established by resistors R3, R6, where the resistance of R3 equals R6, and the output of the op-amp is given by:
Vout=A(V2−V1), where A=R3/R4=R6/R5
Accordingly, the voltage measuring circuit 110 provides an amplified voltage output 114 that is representative of the differential voltage potential between the first and second connectors 101, 102 coupled to a thermocouple, to thereby provide an output 114 that is indicative of the magnitude of the voltage generated by the thermocouple (typically 0-35 millivolts). The output 114 of the voltage measuring circuit 110 is coupled or communicated to an input 142 of a controller 140, as described below.
As shown in
Where the controller 140 is a microprocessor (U1), the voltage magnitude or level may be determined by a preprogrammed algorithm, which processes the output 114 indicative of thermocouple voltage level to determine a duration and frequency at which to controllably switch a connection at 144 for switching on and off the light emitting device 130 (such as light emitting diode DS1). Specifically, one or more batteries 146 provide a voltage V+ that is connected via switch SW1 and applied across a light emitting device 130 (and optionally resistor R1) when the controller 140 or microprocessor U1 controllably switches a connection at 144 for turning the light emitting device 130 on and off.
Based on the output 114 of the voltage measuring circuit 110, the controller 140 or microprocessor U1 preferably switches the light emitting device 130 or light emitting diode DS1 on and off at a given duration and frequency to generate a flash rate that increases as the magnitude of the thermocouple voltage increases, to thereby produce an increasing flash rate to provide an indication of when the voltage magnitude is approaching a sufficient level to cause a valve operator to hold the gas valve open, as described below.
Referring to
Accordingly, a system 150 is provided for indicating when the level of pilot flame output and thermocouple voltage generated therefrom is sufficient to drive a valve operator to hold a pilot valve open. As shown in
While the first embodiment of an apparatus 100 shown in
Referring to
It should be noted that in both of the above embodiments, the apparatus 100 and 200 each comprise a battery, wherein the controller and light emitting device are operably powered by the battery only. Thus, the controller and light emitting device do not derive any electrical power from the voltage generated by the thermocouple. As such, the voltage from the thermocouple will provide for operation of the valve operator to hold the pilot valve open, even if the battery has a voltage output that is too low to operate the apparatus 100, 200 to provide an indication of the level of the pilot flame output. In this manner, the apparatus 100, 200 is isolated from the thermocouple circuit, and monitors the level of the pilot flame output without any risk of interrupting or affecting the thermocouple voltage required to hold the pilot valve open.
While the second embodiment of an apparatus in
Referring to
As shown in
In addition to providing an indication of when the level of pilot flame output is sufficient (or when the thermocouple's generated voltage is at a magnitude sufficient to hold a pilot valve open), the apparatus of the present disclosure may further be configured to monitor the thermocouple voltage to provide one or more diagnostic functions. For example, the controller 140 shown in
According to another aspect of the present disclosure, one or more embodiments of a method are provided for controlling operation of the apparatus to monitor one or more conditions. As stated above, the controller 140 in
Referring to
The controller 140 or microprocessor may also be programmed to provide a method for indicating that the voltage generated by the thermocouple (during pilot flame ignition or thereafter) is at an acceptable peak voltage that is effective to operate a valve operator 18 to hold the pilot valve 16 open (
After ignition of the pilot flame has been established, the method proceeds at step 1005 (in
Furthermore, the controller and/or microprocessor may also be programmed to provide a method for monitoring the thermocouple voltage after establishing a pilot flame to thereafter indicate if the thermocouple voltage has decreased below an acceptable level for reliably operating the valve operator 18. As shown in
The above methods and apparatus provide for controllably switching on and off a light emitting device for providing various indications as to the operational status of the standing pilot flame and thermocouple output, which various indications are illustrated in the Table below.
1.4 v~1.8 v
To further prolong battery life, the above described apparatus and methods may employ a microprocessor having a low power mode for reducing power usage by the microprocessor, by entering into a sleep mode for a predetermined “inactive” time period (e.g., nine seconds) and then returning to operation for a brief time period (e.g., 1 second). In this manner, the apparatus and methods provide an energy conserving “sleep” mode for a predetermined time period, followed by brief operation at given time intervals to determine a voltage input, system state and system output (e.g., provide an indication of voltage level, etc.). Unlike thermal powered circuits that operate from voltage or power derived from a thermocouple or thermo-pile and a large pilot flame required to create the amount of thermal energy required by the circuit, the present apparatus draws no power from the thermocouple and relies on a battery powered circuit that is configured to operate intermittently to prolong battery life up to five years or more.
Accordingly, various embodiments of a method are provided for the above described apparatus. It should be understood that the above described controller and/or apparatus may be configured and/or programmed to determine, from a voltage measuring circuit input, the magnitude of the voltage generated by a thermocouple by utilizing an algorithm within the program, or by alternatively using a look-up table comprising a plurality of values associated with a magnitude of the thermocouple voltage. Likewise, the above described apparatus may alternatively utilize an audible alarm to provide a beep or other sound in place of the indication provided by the light emitting device. Similarly, the above described apparatus may be employed with different forms of gas fired heating appliances and systems.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
