MXPA05004798A

MXPA05004798A - System, apparatus and method for controlling ignition including re-ignition of gas and gas fired appliances using same.

Info

Publication number: MXPA05004798A
Application number: MXPA05004798A
Authority: MX
Inventors: James M Ralson
Original assignee: Saint Gobain Ceramics
Priority date: 2002-11-04
Filing date: 2003-11-04
Publication date: 2005-07-22
Also published as: EP1558872A2; WO2004042485A3; US20040209209A1; WO2004042485A2; CA2504839A1; AU2003291705A1; EP1558872A4; BR0315906A; AU2003291705B2

Abstract

Featured is a gas control device being configured and arranged so as to control operation of a hot surface igniter so it is warmed-up to ignition temperatures of a gas when a call for heat is made and, following ignition, to control operation of the igniter so it is capable of rapidly re-igniting the gas without having to continuously maintain the igniter at or above gas ignition temperatures. More particularly, the gas control device includes circuitry that controls energization of the igniter for ignition of the gas and, after ignition of the gas is determined to have occurred, controls energization of the igniter so that the igniter can be warmed up to ignition temperature conditions within desired re-ignition time periods. Also featured are systems and apparatuses embodying such control devices as well as methods related thereto.

Description

WO 2004/042485 A3! lillllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll ! ll! ll! li li! Illl! l! li il! i III) Published: For In'o-íllíer codes and other abbrevhuions, please refer to the "Gutd- - wilh i ernational search repon ance Notes or: Codes and Abbreviations" appearirig at the begin- - before tlie expiration of the time limit for amending llie ing of each regular issue of the PCT Gazette. claims and to be republished in the event of receipts of amendinents (88) Date orpublication of tlie intcrnational scarc rcport: 21 April 2005 SYSTEM, APPARATUS AND METHOD TO CONTROL THE IGNITION OF GAS, INCLUDING REIGN, AND GAS IGNITION APPLIANCES THAT USE THEM The present application claims the benefit of the provisional application of E.U.A. No. 60 / 423,509, filed November 4, 2003, which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION In general terms, the present invention relates to systems and methods for controlling gas ignition; more particularly to systems and methods for controlling gas ignition, including reignition, when electric resistance lighters are used; more particularly to systems and methods for controlling the ignition of gas in gas igniters and water heaters; and more specifically to systems and methods that use microprocessors / microcontrollers to perform said control functionalities.

BACKGROUND OF THE INVENTION There are several appliances such as cooking stoves, clothes dryers and water heaters in which a combustible material, such as a combustible hydrocarbon (eg propane, natural gas), is mixed with air (ie, oxygen) and burned continuously inside the water heater or appliance in order to provide a continuous source of heat energy. This continuous source of heat energy is used for example to cook food, dry clothes and heat the water to supply a source of hot running water. Since this mixture of fuel and air (ie, fuel / air mixture) does not self-ignite when the mixture is made, an ignition source must be provided to initiate the combustion process and continue to operate until the combustion process is self-sustaining. In the not too distant past, the source of ignition was what was commonly referred to as a pilot flame in which a very small amount of the combustible material and air mixed and burned continuously even while the heating apparatus was not in operation. For several reasons, the use of a pilot flame as a source of ignition was eliminated and a lighter is used instead. A lighter is a device that creates the conditions required for the ignition of the fuel / air mixture at will, which includes spark type lighters such as piezo igniters and hot surface type lighters such as hot surface lighters of silicon carbide . Spark igniters that produce an electric spark that ignites the gas advantageously provide very rapid ignition, i.e., ignition in a few seconds. Problems with spark-type lighters, however, include among other things the electronic and physical noise produced by the spark. With hot surface igniters, such as the silicon carbide hot surface igniter, the tip or heating element is resistively heated by electricity at the temperature required for ignition of the fuel / air mixture; thus, the fuel / air mixture ignites when it flows near the lighter. This process is repeated as required to meet the particular operating requirements of the heating apparatus. Hot surface type lighters are advantageous since they produce negligible noise compared to spark type lighters. Nevertheless, lighters of the hot surface type may require a significant ignition / heating time to resistively heat the resistance lighter to a temperature sufficient to ignite the gas. There are several manufacturers of used hot surface lighters, and a lighter of any manufacturer, due to its particular material composition, mass and physical configuration, will generally heat at a different speed, up to a different final temperature than a cigarette lighter from another manufacturer. For example, when energized at 15 v, a manufacturer's lighters can heat up to a temperature sufficient to ignite the gas, approximately 871 ° C, in about 5 seconds, and at a relatively stable final temperature of approximately 1371 ° C when Energizes for 20 seconds or more. A lighter from another manufacturer may require more or less time to heat up to 1371 ° C, and may reach a lower or higher final temperature. The speed of temperature change and the final temperature reached also depend on the value of the applied voltage. Specifically, when the applied nominal voltage is lower, the igniter heats more slowly and reaches a lower final temperature than when energized at a higher voltage; When the applied nominal voltage is relatively higher, the lighter heats up faster and reaches a higher final temperature. The hot surface ignition systems include a control module that, among other functions, establishes the duration of the lighter's heating period. When it is known that a particular lighter having a brief heating time is to be used, the duration of the lighter heating period can be set at a relatively low value, for example, 15 seconds. However, when the particular lighter to be used has a long heating time, or it is desirable that the system be usable with short or long heating time lighters, the duration of the lighter heating period is set at a relatively large value, for example 45 seconds. With respect to the operation of the system, the lighter's heating period of 15-45 seconds, usually does not present any particular problem because it represents the period between a heat demand and the time necessary to allow the lighter to reach the ignition temperature of the gas . From the point of view of cooking, drying clothes and water heating, these delays are expected and generally imperceptible to the user. For example, the delay in the ignition of a oven is significantly less than the preheating time of the oven to cook or reach roasting conditions. In this way, for the typical user the delay of 15-45 seconds of the gas ignition does not noticeably increase the preheating time nor the time to reach the roasting conditions. However, these periods of lighter heating are a disadvantage from the point of view of the re-ignition of gas during a combustion / heating process, whose gas re-ignition times, according to established industrial standards, are of the order of 4 seconds or less. A conventional furnace gas burner control system that includes a re-ignition capability uses a bimetallic valve control system, where the valve remains open so that the gas can flow for combustion, provided the bimetallic element is subjected to to heat energy above a predetermined amount. To keep the valve open in these types of systems, the lighter must remain on (ie, be hot at or above the ignition temperature) throughout the period of operation of the burner, in order to provide the heat energy required for the bimetallic valve. In addition, for ovens with self-cleaning capacity, the lighter remains hot at or above the gas ignition temperature, during that portion of the cleaning cycle where the oven is heated to elevated temperatures to remove or convert (for example to ash) the residues (eg chips, drippings, etc.) on the interior surfaces of the oven. This maintenance of the lighter at or above the ignition temperature of the gas during the entire cooking / heating or cleaning cycle necessarily reduces the service life of the lighter. In USP 4,615,282 there is a control module in a hot surface ignition system that includes a microcomputer programmed to provide a pre-selected lighter heating period, to allow a lighter to heat up to a gas ignition temperature during normal operation ( for example 15 or 45 seconds), and is also programmed to provide, for testing purposes only, an accelerated lighter warming period (for example 10 seconds), which is shorter than the pre-selected lighter warming period, but sufficiently long to allow the lighter to warm up to a temperature high enough to ignite the gas. The program for providing the period of accelerated heating of the lighter is executed automatically in response to a single signal from a test device detachably connected to the control module. It also provides that this signal is unique and can not be generated by the system itself under normal or abnormal conditions.

In this way, it would be desirable to provide a new system, apparatus or device to control the operation of the lighter so that the lighter is able to re-ignite the gas in the desired periods, without having to keep the lighter in a continuous "on" state. , and methods to control the energization / operation of the lighter. It would also be desirable to provide such a control system and method wherein the lighter is heated up to the ignition temperature to ignite the gas and subsequently the operation of the lighter is controlled in order to keep the lighter in a state of rapid re-ignition of the gas. It would be particularly desirable to provide such a device and method which would control the energization of the lighter, in order to extend the operational life of the lighter in comparison with the operational life of the lighters controlled by means of the prior art control devices. Such systems, apparatuses and devices, preferably, would be simple in construction compared to prior art systems, apparatuses or control devices, and with such methods it would not be necessary for very experienced users to use the device.

BRIEF DESCRIPTION OF THE INVENTION The present invention features a gas control device configured and arranged to control the operation of a hot surface lighter, such that said lighter is heated to or above the ignition temperature of a gas, when a demand for heat is made. Said gas control device is also configured and arranged in such a way that after said ignition operation, the igniter is controlled so that it is capable of rapidly re-igniting the gas (that is, re-igniting the gas in a desired re-ignition period). , without having to continuously maintain the lighter at or above the gas ignition temperature, as is done with conventional gas control circuitry. More particularly, the gas control device includes circuitry that controls the energization of the igniter to ignite the gas and, after it is determined that the ignition of the gas has occurred, controls the energization of the lighter so that the igniter can be heated to the ignition temperature conditions within desired reignition periods. Systems and apparatuses incorporating said control devices are also presented, as well as related methods. A gas control system is also presented which controls the energization of an electric resistance lighter of a power source, and includes a control device configured and arranged in such a way as to control the operation of the electric resistance lighter. More particularly, the control device is configured and arranged to heat the electric resistance lighter to the ignition temperature of a gas that burns or above it. In addition, the control device is configured and arranged such that after successful gas ignition, the operation of the electric resistance lighter is controlled so that the electric resistance lighter is at a temperature lower than the ignition temperature of the igniter. gas, and so the electric resistance lighter can be reheated in order to re-ignite the gas within a desired re-ignition period. In more specific embodiments, the gas control system also controls the operation of one or more gas control valves, said valves controlling the gas flow for combustion. In addition, the control device is configured and arranged to open the gas valves, one or more, after the control device determines that the electric resistance lighter is heated to a temperature at least equal to the temperature of the ignition of gas. Other aspects and embodiments of the invention are set forth below.

Definitions The present invention is understood more clearly with reference to the following definitions: The term gas is understood to mean any combustible gas material as known to those skilled in the art, used with respect to gas ignition apparatus such as those used to cook food and dry clothes (eg stoves, ovens, clothes dryers) and water heaters, and also includes, without limitation, propane, natural gas, municipal gas and manufactured gas.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the nature and desired objects of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying figures, in which similar reference characters denote corresponding parts in the various views, and where Figure 1 is a schematic block diagram of a gas ignition apparatus, including a gas control system according to the present invention, illustrating the control of a gas burner; Fig. 2 is a schematic block diagram of the gas ignition apparatus, including a gas control system according to the present invention, illustrating the control of a plurality of gas burners; Figures 3A-3D illustrate a flow diagram of a control method according to the present invention; Fig. 4 is a schematic block diagram of a gas ignition apparatus, including exemplary igniter control circuitry for a gas control system in accordance with an embodiment of the present invention; and Figure 5 is a flow diagram illustrating the energization process for a lighter that is controlled with the igniter control circuitry of Figure 4.

DETAILED DESCRIPTION OF THE INVENTION As discussed above, the present inventors now provide an ignition system comprising a control device that can control the operation of an electric resistance lighter, such as a sintered electric igniter. Exemplary preferred lighters for use in the ignition system of the invention include sintered ceramic lighters such as lighters which are described, for example, in U.S. Pat. Nos. 6,852,629; 6,474,492; and 5.801361, among others. The control device is suitably configured to (i) heat the lighter to a temperature greater than or equal to the ignition temperature of a gas for combustion, and (ii) after successful ignition of the gas, control the operation of the igniter so that the lighter is at a temperature lower than the ignition temperature of the gas, and thus the electric resistance lighter can be reheated in order to re-ignite the gas within a desired re-ignition period. Preferably, the temperature of the lighter is maintained at the desired level (for example at the ignition temperature or below the ignition temperature) by monitoring the amperage. Preferably, the system can only open the gas flow when a predetermined current level in the lighter is reached. Conveniently, the control device can operate in such a way that the electric resistance lighter is maintained at a temperature of about 100 ° C or more, for example 200 ° C, 300 ° C, 400 ° C, 500 ° C, 600 ° C , or 000 ° C or more, less than a desired gas ignition temperature (eg, a desired gas ignition temperature may be about 1100 ° C, 1200 ° C, 1300 ° C or 1400 ° C, for example 100 ° C to 1400 ° C). Also, conveniently, the electric resistance lighter can be maintained at a non-elevated temperature (i.e., it can be maintained at room temperature) during periods without ignition. However, for many applications, it is preferable that the igniter be maintained at some temperature above room temperature, but below the ignition temperature (e.g. below about 1200 ° C., 1 150 ° C or 1 100 ° C) during periods when ignition is not required or desired. Preferably, an ignition system of the invention provides for rapid ignition of gaseous fuel, for example where ignition occurs in approximately 6 seconds or less after activation of the ignition system (i.e., the reignition period), preferably approximately 5, 4, 3 or even 2 seconds after activation of the system for ignition.

Referring now to the various figures, in which similar reference characters refer to similar parts, a schematic block diagram of a gas-fired water heater or gas igniter, 10, is shown in FIG. such as a gas oven or stove that includes a gas control system, 100, according to the present invention. The gas ignition apparatus, 10, also includes a control mechanism 12, a master or master gas valve, 32, a gas control valve or burner, 34, gas supply line, 36, a burner 38, a flame detector mechanism, 50, and a lighter 60. The electrical power to operate the components of the gas ignition apparatus comes from an energy source 20, and the gas that is burned in the gas ignition apparatus is of a source of gas, 30. In exemplary exemplary embodiments, the gas source 30 is a gas supply line within a house, said gas line typically includes a manual shut-off valve and is interconnected with one or more gas supply lines. gas from a gas service company. Also, the source of electrical energy, 20, is the central electrical panel inside a house, which is electrically coupled by means of a switch with the electrical lines of an electric service company. It must be recognized that the electrical voltage or line voltage supplied depends on the location in the world, and on the operational scale or allowed variation. In the United States, where the specified line voltage is 220 VAC, the nominal line voltage normally varies between approximately 208 VAC and approximately 240 VAC. In Europe and other parts of the world where the specified line voltage is 230 VAC, the nominal line voltage normally varies between approximately 220 VAC and approximately 240 VAC. In this way, the variation of line voltage can vary universally anywhere between approximately 176 VAC and approximately 264 VAC. In the United States, there are cases where other nominal line voltages are found; in one case, the nominal line voltage is 120 VAC, which varies between approximately 102 VAC and approximately 132 VAC, and in another case the nominal line voltage is 24 VAC, which varies between approximately 20 VAC and approximately 26 VAC. The control mechanism 12 is any of several known mechanisms or switches that can provide output signals to the microcontroller 1 10, in response to user inputs / actions, in order to selectively turn off and turn on the gas burner 38 and also selectively adjust the heat output from the gas burner. In an exemplary exemplary embodiment, the control mechanism 12 is a rotary switch known to those skilled in the art, which is selectively rotated by a user to thereby provide the necessary output signals. In alternative embodiments, the control mechanism 12 is one or more pressure sensitive switches used to turn the gas burner 38 on and off and to select a power rating (e.g., a temperature). The pressure-sensitive switch can be used in combination with an LCD or other type of display that displays the on-off condition and information of the degree of power to the user. In the illustrated embodiment, a redundant gas valve subsystem comprised of a main valve 32 and a gas control valve, 34; however, this should not be considered as limiting the present invention to the illustrated modality. The gas control device 100 of the present invention is contemplated and is adaptable for use with gas ignition apparatus having a single gas control valve between the gas source 30 and the gas burner 38. The supply line of gas, 36, is any of several pipe products known to those skilled in the art that are suitable for use with gas and suitable for interconnecting the main valve 32, the gas control valve, 34, of the gas ignition apparatus, with the gas source 30 and in turn with the gas burner 38. The main valve 32 is any of several valves known to those skilled in the art, such as a solenoid valve, which is selectively operable in response to a control signal from the microcontroller 1 10. In an illustrated embodiment, the main valve 32 is suitably configured to be an open / close valve and to be in an open position or closed in response to one or more signals received from a control device such as the microcontroller 10. Similarly, the gas control valve 34 is any of the gas control valves known to those skilled in the art, which may be selectively adjusted in any of several positions, between the closed and fully open position, inclusive, in response to the control signals of a control device such as the microcontroller 1 10. In this way, the gas control valve 34 adjusts the amount of gas flowing through the gas control valve to the burner and consequently selectively controls the amount of heat energy produced by the gas burner. gas 38. The gas burner 38 is any one of several known burners, or structures developed using well known principles or techniques by which a combustible gas is controllably intermixed with the surrounding atmosphere, in order to establish a combustion process. The flame detector mechanism, 50, is normally provided for use in determining the presence of continuous combustion of the fuel / air mixture. In one embodiment, the detector mechanism incorporates the electric phenomenon of flame rectification flame between the lighter 60 and an insulated metal cover surrounding the lighter as the mechanism for detecting the presence of a flame. In this embodiment, the presence of a flame is detected or determined if a current leak between the igniter and the cover exceeds a predetermined value. In other embodiments, the flame detector mechanism is a type of detector thermopile that detects the temperature of the area in which the fuel / air mixture burns, or comprises an optical detector. The flame detector mechanism may also comprise the lighter shield or the grounded burner element. The detector mechanism 50 is operatively coupled or interconnected with the microcontroller 110 to provide indications or signals representative of the presence of a flame or the absence of a flame. The actions performed by the microcontroller 1 10 in response to said indications are described below. The lighter 60 is any one of several electric resistance or hot surface igniters known to those skilled in the art, suitable for the intended use / application described herein. In a particularly illustrative embodiment, the lighter 60 is a ceramic / intermetallic hot surface lighter, such as the Norton Mini Igniters®, manufactured by St. Gobain Industrial Ceramics Norton Igniter Products. Said ignition device normally includes a heating element that extends outwardly from one end of the base to which it is secured. This is not considered to be limiting since the present invention can be used with other types of hot surface igniters, as well as other types of ignition devices or lighters, such as for example Norton CRYSTAR Ignites®. In specific exemplary embodiments, the electric surface igniter 60 is an electrical resistance lighter having a nominal operating voltage of 18, 60, 70, 80, or 150 volt (V) AC; however, it should be recognized that the present invention is not particularly limited to these nominal operating voltages. The gas control system 100 includes a microcontroller 1 10, an energy switching mechanism, 120, and a mechanism for monitoring the lighter 60, in order to determine when the lighter has reached a temperature suitable for igniting the gas. In an illustrative embodiment, the monitoring mechanism is a current sensing mechanism 130 as is known in the art, which detects the current of the lighter. As is known to those skilled in the art, a relationship between the igniter current and the temperature of the lighter 60 can be established. In this way, when the igniter current detected by the current detecting mechanism 130 reaches a predetermined value, in further referred to as the threshold of the current, it is known that the lighter 60 has achieved the minimum operating temperature necessary to ignite the gas-air mixture. When the detected current of the lighter reaches the current threshold, this condition is sometimes referred to as the ignition source "is proven". It should be recognized that other mechanisms known to those skilled in the art are contemplated for use in the present invention to determine the operational condition of the lighter 60. For example, a temperature sensitive element (e.g., a bimetallic element) may be placed together to the lighter 60 in order to provide a signal indicative of when a temperature exceeds a predetermined value. The power switching mechanism, 120, is any of several circuits or circuit elements which, in response to control signals from the microcontroller 10, at least selectively energizes the igniter 60 (i.e., ignites the igniter), in such a manner of heating or reheating the lighter so that the lighter is hot enough to ignite the gas, and de-energizes it (that is, turns off the lighter) to stop the heating of the lighter's resistance. As described below, in one embodiment of the present invention, the power switching mechanism, 120, is also controlled by the microcontroller 1 10, after the gas is properly turned on, in order to keep the lighter 60 at a predetermined temperature. or on a predetermined temperature scale, less than the gas ignition temperature. The system may further comprise one or more improved ignition elements such as those described in the published patent application of E.U.A. copending and the same beneficiary, 2003-0164368A1, which is set forth below and with particular reference to Figure 4. In an illustrative embodiment, the power switching mechanism, 120, includes a thyristor, a rectifier that blocks the current in the both forward and reverse. In a more specific embodiment, the thyristor is a triac such as those known in the art to block the current in any direction until it receives a gate impulse from the microcontroller 110. Upon receiving the gate impulse, current flows through the gate. of the triac. The thyristor or triac is electrically coupled to the electric power source 20 and the hot surface igniter 60, in order to control the flow of current from the power source through the hot surface igniter. In this way, in the event that the thyristor or triac is blocking the current flow, the hot surface igniter 60 is de-energized. In the event that the thyristor or triac has received a gate pulse, current flows through the hot surface igniter 60, thereby energizing the igniter and causing it to heat up. The microcontroller 110 includes a processing unit 112, a random access memory, 114, a non-volatile memory, 16, and an application program for execution in the processing unit. The application program includes instructions and criteria for receiving and processing the various signals input to the microcontroller 1 0 from the current detector mechanism 130 of the lighter, the flame detector mechanism 50 and the control mechanism 12 of the gas ignition apparatus. The application program also includes instructions and criteria in order to provide output control signals to the main gas valve, 32, the gas control valve, 34, and the power switching mechanism 120, thereby controlling the intake of the gas. gas to the combustion area, energizing the hot surface lighter 60 and keeping the lighter in a waiting condition to re-ignite the gas within a predetermined period. The application program, which includes the instructions and their criteria, is discussed below with respect to Figures 3A-D. The processor unit 112 is any of several microprocessors known to those skilled in the art to perform the functions described herein and operating in the intended medium. In an exemplary embodiment, the processing unit 1 2 is Samsung S3C9444 or Microchip 12C671. The random access memory (RAM) 1 14 and the non-volatile memory 1 16 is any of several such memory devices, memory chips, or the like, as is known to those skilled in the art. Non-volatile memory 1 16, more particularly, may comprise flash or axis type memory. In a particularly illustrative embodiment, non-volatile memory 1 16 includes non-volatile random access memory (NVRAM), read-only memory (ROM), such as EPROM. In a particular embodiment, the processing unit 1 2, RAM 4 and non-volatile memory 1 16 are arranged / arranged in order to be colocalized on a single integrated chip. This is not particularly limiting since these components can be configured and arranged in any of several ways known to those skilled in the art. The operation of the gas control system, 100, of the present invention, as well as an exemplary exemplary gas ignition apparatus, 10, incorporating said system, is best understood from the following disclosure and with reference to FIGS. D. Reference should also be made to Figure 1 and the preceding discussion of the features and functionalities of the gas control system 100 not provided or set forth in any other way below. As indicated above, the following also describes the functions and instructions and criteria of the application program running on the processor 12 of the microcontroller 110. The gas control system 100 is operated in such a manner that the hot surface igniter 60 is de-energized and the main gas and gas control valves, 32, 34, are closed during times when no heat energy is produced by the gas ignition device device 10, such as a heating unit, for example. example a water heater. Therefore, during said non-heat producing times, the gas control system 100 is in an inactive state. When the gas ignition apparatus 10 produces heat energy, an input signal is provided to the microcontroller 1 10, such as a signal from the control mechanism 12. Said signal corresponds to a signal to initiate the energization process of the surface igniter 60. , in order to ignite the gas / gas burner 38, step 402. In case the gas control system 100 is de-energized when it is in the inactive state, such as after a period has passed without receiving signals for energize the lighter 60, and to ignite the gas / gas burner 38, said signal can be manifested by restoring the energy to the control system. Such signals are also essentially a demand for the production of heat energy. After receiving demand signals for production of heat energy, the microcontroller 110 performs a pre-start check to detect the presence of a flame, steps 404, 406. More particularly, the microcontroller 1 10 evaluates the outputs, if any, of the flame detection mechanism 50 to determine if the output signals indicate the presence of a flame. If it is determined that a flame is present (YES, step 406) where none must be present, that indicates a fault and the microcontroller 1 10 sends a closing signal in order to cause the gas ignition apparatus 0 to be put on a closing mode, step 408. In the closing mode, the igniter 60 and the gas valves 32, 34, of the gas ignition apparatus 10 can not operate (for example, the igniter can not be energized and the valves can not be they can be opened). Normally, the manufacturer of the gas ignition apparatus provides a mechanism by which the closing mode can be readjusted, for example, after a specified period has elapsed or after the electrical power for the appliance has been removed and subsequently restored. If it is determined that a flame is not present (NO, step 406), the microcontroller 1 10 sends a control signal to energize the igniter 60 the igniter to heat up to the temperature conditions of gas ignition, step 410. More particularly, the microcontroller 110 sends one or more control signals to the power switching mechanism 120 to supply electrical power (ie, voltage and current) to the lighter 60, to energize the lighter. In an exemplary exemplary embodiment, the switching mechanism 120 is selectively operated by the microcontroller 1 10 so that the lighter 60 is heated up to the ignition temperature of the gas. Using the outputs of the monitoring mechanism of the lighter, the microcontroller 110 monitors the lighter, for example the temperature of the lighter or the parameters may be related to the ignition temperature (for example the current lighter), step 412, and evaluates these conditions to determine if the temperature of the lighter is greater than or equal to the ignition temperature of the gas, step 414. As indicated above, the igniter current can be related to the temperature of the lighter. In this manner, in an exemplary embodiment, the microcontroller 1 10 monitors the current detection mechanism of the igniter, 130, to determine whether the detected or measured igniter current exceeds a current threshold. In this way, if the igniter current detected or measured is greater than or equal to the current threshold, then the temperature of the lighter is correspondingly greater than or equal to the ignition temperature of the gas. If it is determined that the temperature of the igniter is less than the ignition temperature of the gas (NO, step 414), a determination is made to see if a first suspension record has expired, step 416. In other words, a determination is made to see if the time that has elapsed since the signal was generated to energize the lighter 60 is greater than or equal to a previously specified period. As indicated herein, a given lighter is typically characterized by a specific period required to heat the lighter so that it reaches the minimum temperature required for the ignition of the gas. In this way, the period previously specified for the first suspension record is established based on the period of heating of the lighter that is used. In an illustrative mode, the previously specified period is 15 seconds. If it is determined that the first suspension record has expired (YES, step 416), then the microcontroller 110 sends a closing signal thereby causing the gas ignition apparatus 10 to be put into a closing mode, step 408. If it is determined that the first record of suspension has not expired (NO, step 416), then the process repeats the process outlined in steps 412 and 414. If it is determined that the temperature of the lighter is greater than or equal to the temperature of the lighter (NO , step 414), the microcontroller sends one or more control signals that cause the main gas valve 32 and the gas control valve 34 to open allowing the gas to flow to the gas burner 38, step 420. In the exemplary embodiment, the microcontroller 10 evaluates the current of the detected or measured lighter and if it is determined that the detected or measured current is greater than or equal to the current threshold, it is determined that the lighter 60 is at a temperature greater than or equal to the ignition temperature of the gas. After the opening of the gas valves 32, 34, a period is normally established by which the gas coming from the gas burner 38 must be ignited and a continuous sustained combustion of the gas must be established. Normally, a period of approximately 4 seconds is established to do the above. In this way, after the valves 32, 34 are opened, a determination is made to see if a second suspension record related to the preceding period has expired, step 422. If the period has not elapsed (NO, step 422) , the valves 32, 34 are kept open and the gas continues to flow to the gas burner 38. If it is determined that the second record of the suspension has expired (YES, step 422), the microcontroller 110, using signals from the detection mechanism of the flame 50, determines whether there is flame indicative of successful ignition of the gas and the establishment of continuous sustained combustion of the gas, step 424. If a flame is detected (SI, step 424), the microcontroller 1 10 continues to keep the valves open ( for example, continue to energize the valves in order to keep them open), step 430, and initiate or establish the re-ignition functionality of the present invention as described below. Since the valves are kept open, signals are also generated to control or regulate the heat output from the gas burner 38. More particularly, the control mechanism 12 or a temperature regulating device of the gas ignition apparatus further provides signals (for example a line voltage signal) to control or regulate the heat output of the gas burner 38. In an exemplary embodiment, the temperature regulating device or the control mechanism 12 sends a line voltage signal to the control valve of gas, 34, which in turn regulates the amount of gas that passes through the valve and thus the amount of heat energy produced by the gas burner. The process also continues to evaluate the operational status of the gas ignition apparatus 10 to determine whether the particular heating cycle is completed or completed, step 432. The heating process continues (NO, step 432) until it is determined that the cycle heating has finished (YES, step 432). When the particular heating cycle is complete or finished, the valves 32, 34 are closed, the igniter 60 is de-energized and the re-ignition functionality is completed, step 434. As indicated above, if a flame is detected (YES, step 424) , the microcontroller 110 initiates or establishes the re-ignition functionality of the present invention as described below. More particularly, the microcontroller 1 10 sends one or more control signals to the power switching mechanism 120 to continue energizing the lighter 60, but in order to keep the lighter in a wait or re-ignition wait, step 440, and continues to monitor the presence of a flame, step 450. As for the energization of the lighter 60, the microcontroller 1 10 controls the power switching mechanism in such a way that the voltage and current applied to the lighter are such that the lighter is kept at a temperature or at a temperature scale that is lower than the ignition temperature of the gas, but high enough so that the igniter can be heated to the minimum temperature for the ignition of the gas in a period less than the predetermined one. In exemplary modalities, the default period is 4 seconds or less; more particularly, approximately 2 seconds; and more specifically on the scale of approximately 2 seconds and approximately 4 seconds, inclusive.

From monitoring the presence of the flame, step 450, a determination is made to see if the flame is present or not, step 452. If it is determined that the flame is present (YES, step 456), the process continues to perform the steps 450 and 452 until the heating cycle ends or a flame loss is detected. In an exemplary embodiment, the microcontroller 1 10 detects the flame loss in one second or less, more particularly in about 0.8 seconds. If it is determined that there is no flame (NO, step 452), then the microcontroller 1 10 sends one or more control signals to the power switching mechanism 120 in order to cause the igniter 60 to be reheated to the ignition temperature conditions of gas, step 454. Since the lighter 60 is maintained at a holding temperature (step 440), the time to reheat the lighter and restore the gas ignition temperature conditions is from about 2 to about 4 seconds as indicated above. After a control signal is sent to energize the igniter and to restore the gas ignition temperature conditions (step 454), it is determined whether a predetermined period has elapsed since said control signal was generated, step 456. If the predetermined period has not elapsed (NO, step 456), the process continues to execute steps 454 and 456. If the predetermined period has elapsed (YES, step 456), the process returns to step 424 (FIG. 3B) for an evaluation to determine if a flame is detected again.

If a flame is not detected (NO, step 424), either when the gas valves were opened initially after initially energizing the igniter, or after attempting to re-ignite the gas after detection of a flame loss, the microcontroller 1 10 sends one or more control signals to the power switching mechanism 120 to de-energize the lighter 60, and sends control signals to close the main and gas control valves, 32, 34, step 460. In addition, a counter representing the number of test cycles for ignition is increased by one and the number in the counter is compared with a maximum number of test cycles for ignition, step 462. If it is determined that the counter equals the maximum number of test cycles for ignition (YES, step 462), then the microcontroller 1 10 sends the closing signal, step 408. If it is determined that the counter number is less than the maximum number of test cycles even to ignition (NO, step 464), then the system is purged to dissipate unburned gas or combustion residual products, step 464. A predetermined period is established for said purge which is sufficient time for the dissipation of unburned gas or products residuals of combustion. The process continues with said purge (NO, step 466), until it is determined that the predetermined ignition test period has elapsed (YES, step 466). After the predetermined period has elapsed, the process returns to step 404 (FIG. 3A) to perform the pre-start verification process. Referring now to Figure 2, there is shown a schematic block diagram of a gas ignition apparatus having a plurality of gas burners, 38a, 38b, including a gas control system 100 'according to the present invention. invention, which is configured to separately control each gas burner. In FIG. 2, alpha characters were added to the reference numbers used in FIG. 1 to identify the components corresponding to those of FIG. 1, but provided to control one of the gas burners illustrated in FIG. 2. In this way, reference will be made to the preceding discussion of Figure 1 and Figures 3A-D to see the details of the corresponding elements / components and functionality. As for the microcontroller 110 'of this mode, the microcontroller, which includes the program of applications that are executed in the processor 12 of the microcontroller, can be, for example, appropriately configured so that the microcontroller can separately control the operation of each gas burner independently of the operation of the another gas burner, or alternatively, for example, the microcontroller can be configured to control only one burner at a time. For example, one gas burner could operate normally while the other of the gas burners goes through re-ignition of the gas. However, in the case of realization of the closing mode (step 408), all gas burners can be affected due to the closure of the main gas valve. As regards other aspects of the microcontroller 1 10, the constituents thereof and the program of applications for execution, reference should be made to the preceding discussion with respect to figures 1 and 4A-D. It should be recognized that although Figure 2 is illustrative of burners of a gas ignition burner, the circuitry and system configuration illustrated in Figure 2 are easily adaptable for use in the control of a wide range of gas ignition apparatuses. which have a plurality of gas burners, as well as the gas burners used in baking and roasting ovens. For example, in an exemplary exemplary gas ignition furnace in accordance with the present invention, said furnace would include a gas main valve in series with a baking gas valve to control baking and a gas control valve for roasting to control the roast. This is similar to the arrangement of the first and second gas control valves, 34a, b, and the main gas control valve, 32, as shown in Figure 2. However, unlike the operation of a gas-fired oven, in the case of an oven, the gas-control valve for baking and the gas-control valve for roasting, although separately controllable, are neither energized nor open at the same time because a furnace is normally used for bake or to roast and not to do both at the same time. Regarding other aspects, reference should be made to the foregoing disclosure of Figures 1-3 for further details of the use of the gas control system of the present invention, for a gas-fired oven and other gas ignition applications. not listed here specifically in another way. Referring now to Figure 4, a schematic block diagram of a gas ignition apparatus including a gas control system according to an embodiment of the present invention is shown. Reference should be made to USSN 10 / 090,450, filed March 4, 2002 (published patent application of USA 2003-064368A1 to Chodacki et al., Published September 4, 2003), the teachings of which are incorped herein by reference in its entirety, including details not otherwise shown in the figures herein referred to below or described below. Reference should also be made to the preceding discussion of Figures 1 and 3A-D to see the details of structure / features / common components and method steps not otherwise described below. The gas control system 300 further includes a zero crossing circuit, 302, and a line voltage measurement circuit, 304, and the application program for execution in the processor 112 of the control robot 110, includes further instructions and criteria for controlling the energization of the lighter according to this embodiment of the present invention. The zero crossing circuitry, 302, is electrically coupled to the power source 20 to monitor the line voltage of the power source, and is operatively coupled with the microcontroller 1 10. The zero crossing circuitry, 302, is any of several circuits known to those skilled in the art, which is configured and arranged in order to be able to detect or determine when the AC line voltage crosses the time axis, in other words it passes through zero voltage. The zero crossing circuitry, 302, is also configured and arranged so as to provide an output signal to the microcontroller 110 when the AC line voltage passes through zero voltage. In an exemplary embodiment, the output signals are digital signals. The line voltage measuring device 304 is electrically coupled to the power source 20 and is operatively coupled to the microcontroller 10. The line voltage measuring device 304 includes any of several known line voltage measuring circuits. for those skilled in the art, which is configured and arranged to monitor and determine the line voltage of the power source 4 and to provide output signals representative of the determined line voltage. More particularly, such circuits are configured and arranged so as to be able to quickly determine the line voltage and provide such output signals to the microcontroller 110. In a more particular embodiment, the line voltage measuring apparatus, 304, comprises a conventional resistor divider filter circuit In an exemplary mode, the output signals are analog signals; however, the circuitry can be configured in order to provide digital output signals. The power switching mechanism, 320, comprises a thyristor 322, which is a rectifier that blocks the current in the forward and reverse directions. In a more specific embodiment, the thyristor 322 is a triac as is known to those skilled in the art, which blocks the current in any direction until it receives a gate pulse from the microcontroller 110. Upon receiving the gate pulse, the current It flows through the triac. The thyristor 322 or triac is electrically coupled to the power source 4 and the hot surface igniter 60, in order to control the flow of current from the power source through the hot surface igniter. Thus, in the case where the thyristor 322 or triac is blocking the flow of the current, the hot surface igniter 60 is de-energized. In the case where the thyristor 322 or triac has received a gate pulse, the current flows through the hot surface igniter 60 thereby energizing the igniter and causing it to become hot. The operation of the gas control system, 300, is best understood from the following discussion and with reference to Figures 3A-D and 5. Reference should also be made to Figure 4 and the preceding discussion of Figures 4 and 1 to see the features and functionalities of the control system 300 not provided or set forth in any other way later. As indicated above, the following also describes the functions and instructions, and the criteria of the application program executed in the processor 12 of the microcontroller 1 10. However, the following discussion is mainly limited to describing the particular process associated with the application. energization of the lighter (step 410, figure 3A) in accordance with this embodiment of the present invention.

As indicated above with respect to Figure 3A, if it is determined that a flame is not present (NO, step 406), the microcontroller 1 10 sends a control signal to energize the lighter 60 to heat it to the temperature conditions of gas ignition, step 410. According to this embodiment, the microcontroller 1 10 sends a signal (for example a gate pulse) to the triac or thyristor 322, to trip the thyristor so that the current from the power source 4 flows through the hot surface igniter 60. More particularly, the microcontroller 1 10 controls the triac or thyristor 322, such that the current flows continuously and thus "full" voltage is supplied to the hot surface igniter 60, step 502. This normally produces an "overvoltage" condition, that is, the voltage developed through the hot surface igniter 60 is greater than the nominal operating voltage for the igniter ers Consequently, the hot surface igniter 60 heats faster at a given temperature and also produces more heat energy in the lighter. As indicated above, the line voltage measuring device 304 monitors the line voltage of the power source 20 and provides output signals representative of the line voltage to the microcontroller. After receiving said energizing signal, the microcontroller 1 10 processes the output signals of the line voltage measuring device, 304, to determine the amplitude of the line voltage, step 510. The microcontroller 110 evaluates the determined line voltage or measured to determine the period during which the "full line" voltage is to be applied or supplied to the hot surface igniter 60, step 512. This period is then referred to as the "full" period. More particularly, the processor 112 compares the determined line voltage with a look-up table to determine the appropriate "full" period for the determined line voltage. In a more specific embodiment, the look-up table is stored in the non-volatile memory 1 16. In an exemplary embodiment, this process of determining the "full" period is terminated in about one second after the signal to energize the lighter is received by the microcontroller 110. Accordingly, the processor 112 adjusts the "full" period each time the microcontroller 110 receives an input signal to energize the hot surface igniter 60 based on the measured line voltage each time. In other words, the time that the "full" voltage will be applied or delivered to the hot surface igniter 60 will vary depending on the line voltage measured each time the igniter is energized. For example, if the measured voltage is at the lower end of a given voltage scale, then the "full" period would be adjusted to compensate for this by applying the "full" voltage for a longer period. Similarly, if the measured voltage is at the upper end of a given voltage scale, then the "full" period would be adjusted to compensate for this by applying the "full" voltage for a relatively shorter time than for the end-line voltage. lower.

After determining the "full" period, the processor 1 12 continuously determines whether this time has expired, step 504. If it is determined that the period has not expired (NO, step 504), then the microcontroller 1 10, more particularly the processor 112, controls the triac or thyristor 322 in such a way that the "full" voltage continues to be applied or supplied to the hot surface igniter 60, step 502. If it is determined that the period has expired (YES, step 504), then the processor 1 12 controls the triac or thyristor 322 to regulate the voltage applied to the triac or thyristor, step 506. Then, the process returns to step 412 of FIG. 3A. It should be recognized that the energization process of the lighter described with respect to Figures 4 and 5, it is also adaptable for use in energizing the lighter when the gas is re-ignited after the detection of a flame failure (steps 450, 452, FIG. 3C). In such a case, the lighter is in a non-hot or hot condition to a standby condition, before applying the full voltage as described above. In such cases, the microcontroller 1 10 would similarly determine a period of full voltage, control the application of the full voltage to the igniter during the determined period, and after the expiration of the determined period would then regulate the voltage to the nominal operation value for the lighter. Although a preferred embodiment of the invention has been described using specific terms, said description is for illustrative purposes only and it is understood that changes and variations may be made without departing from the spirit or scope of the following claims.

Claims

39 NOVELTY OF THE INVENTION CLAIMS

1. - A gas control system that controls the energization of an electric resistance lighter of a power source, said control system comprising: a control device that is configured and arranged to control the operation of the electric resistance lighter; wherein the control device is configured and arranged to heat the electric resistance lighter to a temperature greater than or equal to an ignition temperature of a burning gas; and wherein the control device is also configured and arranged such that after successful ignition of the gas, the operation of the electric resistance lighter is controlled so that the electric resistance lighter is at a temperature lower than the ignition temperature. of gas, and so that the electric resistance lighter can be reheated in order to re-ignite the gas within a desired re-ignition period.

2. The gas control system according to claim 1, further characterized in that the gas control system controls the operation of one or more gas control valves, said valves control the gas flow for combustion, and wherein the control device is configured and arranged to open the gas valves, one or more, after the control device determines that the electric resistance lighter is heated to a temperature at least equal to the ignition temperature of the gas.

3. The gas control system according to claim 1, further characterized in that the control device is configured and arranged to selectively control the energization of the electric resistance lighter after successful gas ignition, wherein the gas heater The electrical resistance is selectively energized so that the electric resistance lighter is maintained at a temperature that is less than the ignition temperature of the gas, and which is set such that a time required to reheat the electric resistance lighter from the A temperature lower than the ignition temperature of the gas up to a minimum temperature required for the ignition of the gas is less than a desired period for re-ignition.

4. The gas control system according to claim 3, further characterized in that the control device includes: a switching mechanism operatively connected between the electric resistance lighter and the power source; a microcontroller and an application program for execution in the microcontroller; and wherein the application program includes instructions and criteria for sending control signals for the switching mechanism, for selectively controlling the voltage applied to the electric resistance lighter, sending control signals for the switching mechanism, to heat the electric resistance lighter to the ignition temperature of the gas, and send control signals to the switching mechanism, after successful ignition of the gas, to keep the electric resistance lighter at a lower temperature than the ignition temperature of the gas.

5. - The gas control system according to claim 4, further characterized in that the application program also includes instructions and criteria for: heating the electric resistance lighter to the temperature that is set in such a way that a time required for reheating the electric resistance lighter from the set temperature to a minimum temperature required for the ignition of the gas, is in a desired period for re-ignition.

6. - A gas control system that controls the energization of an electric resistance lighter from a power source, and that controls the operation of one or more gas control valves, these valves control the flow of gas for combustion , said gas control system comprising: a control device that is operatively coupled between the electric resistance lighter and the power source, and being operatively connected to the gas valves, one or more; wherein the control device is configured and arranged to selectively apply a voltage to the electric resistance lighter that responds to an input signal that demands heat; and wherein the control device is configured and arranged: so that the electric resistance lighter 42 is heated by the voltage applied selectively to be at a temperature greater than or equal to a temperature to ignite the gas, a temperature of ignition of the gas, such that after determining that the electric resistance lighter has been heated to the temperature of Gas ignition, gas valves, one or more, open, and so after determining that the gas has been ignited correctly, the voltage applied to the electric resistance lighter is controlled to maintain the electric resistance lighter at an operational temperature that is lower than the ignition temperature of the gas.

7. The gas control device according to claim 6, further characterized in that the control device is configured and arranged so that the voltage applied to the electric resistance lighter after determining that the gas has been ignited correctly, is controlled so that the electric resistance lighter is at a set temperature such that a time that is required to reheat the electric resistance lighter from that temperature to a minimum temperature required for the ignition of the gas is within a desired period for the reignition.

8. An ignition system comprising: a control device that can control the operation of an electric resistance lighter; wherein the control device is configured to (i) heat the igniter to a temperature greater than or equal to an ignition temperature for a burning gas; and (ii) after the successful ignition of 43 gas, controlling the operation of the lighter so that the lighter is at a temperature lower than the ignition temperature of the gas, and so that the electric resistance lighter can be reheated to re-ignite the gas within a desired re-ignition period.

9. The ignition system according to claim 8, further characterized in that an electric resistance lighter is operatively connected to the control device.

10. - The ignition system according to claim 9, further characterized in that the electric resistance lighter is in electrical communication with the control device.

11. - The ignition system according to claim 8, further characterized in that the lighter is a concrete ceramic lighter.

12. - The ignition system according to claim 8, further characterized in that after the ignition of the gas, the lighter is maintained at a temperature lower than the ignition temperature of the gas, but higher than the ambient temperature.

13. - The ignition system according to claim 8, further characterized in that the desired re-ignition period is approximately four seconds or less.