Patent Application
20190338951
The present invention is related to a gas appliance, and more particularly to a gas appliance which could sense flames by utilizing a thermocouple.
Gas appliances are usually utilized as heating devices. As comparing to electro-thermal heating devices, the gas appliances provide more heat energy by burning gas. In addition, the gas appliances also have a heating time and a response time which are faster than the electro-thermal heating devices.
Referring to
When the user operates the conventional gas appliance 1, the user would press the knob 124 to open the electromagnetic valve of the valve body 122 for supplying the gas to the burner 10, and rotate the knob 124 to the ignition position to trigger the switch 126 and the ignitor 14 for igniting. Referring to
During the ignition procedure, in the beginning, although the user could see the generated flames, it is required for the thermocouple 18 to be heated for a longer time to output the sensing voltage which could reach the predetermined voltage V. Then, the user could release the knob 124. When the user releases the knob 124 too early, the electromagnetic valve would not have the constant magnetic field yet, and the gas pipe p would be blocked instantly. However, the user could not identify whether the electromagnetic valve has the constant magnetic field or not, and could only identify rely on his experience, resulting in inconvenience.
Referring to
However, the sensing voltage output from the thermocouple 18 decreases with a speed much slower than its increasing speed while the thermocouple 18 is heated. Hence, when the flames are extinguished by wind, the sensing voltage requires a longer time (i.e., more than one minute) to become lower than the predetermined voltage V. In other words, when the flames are extinguished by wind, it requires more than one minute for the electromagnetic valve to block the gas pipe p.
In this way, when the flames are extinguished with a large gas flow rate, a large amount of gas would leak out of the burner 10 for more than one minute, thereby affecting the security of the conventional gas appliance 1, which could be even worse when there is additional spark to ignite the leaking gas.
In view of the above, an object of the present invention is to provide a gas appliance and a control method thereof which could identify a successful ignition faster.
Another object of the present invention is to provide a gas appliance and a control method thereof which could block the gas earlier when the flames are extinguished, thereby improving the security of utilization.
To achieve the object mentioned above, the present invention provides a control method for a gas appliance, wherein the gas appliance includes a burner, a gas valve, an ignitor, and a thermocouple. The burner includes at least one flame port; the gas valve is disposed on a gas pipe communicating with the burner, and is controllable to open or block the gas pipe; the ignitor is disposed adjacent to the flame port of the burner, and is controllable to ignite gas output from the flame port; the thermocouple is disposed adjacent to the burner, and is adapted to sense flames and output a corresponding sensing voltage; the control method comprises steps of: A. controlling the ignitor to ignite, and controlling the gas valve to open the gas pipe; B. receiving the sensing voltage output from the thermocouple; C. stopping the ignitor from igniting and controlling the gas valve to keep the gas pipe be in an open state when the sensing voltage increases to a first voltage; D. receiving the sensing voltage output from the thermocouple continuously, and controlling the gas valve to block the gas pipe when the sensing voltage decreases from higher than a second voltage to lower than the second voltage, wherein the second voltage is higher than the first voltage.
The present invention provides a gas appliance including a burner, a gas valve, an ignitor, a thermocouple, and a control device. Wherein, the burner includes at least one flame port; the gas valve is disposed on a gas pipe communicating with the burner, and is controllable to open or block the gas pipe; the ignitor is disposed adjacent to the flame port of the burner, and is controllable to ignite gas output from the flame port; the thermocouple is disposed adjacent to the burner, and is adapted to sense flames and output a corresponding sensing voltage; the control device is electronically connected to the gas valve, the ignitor, and the thermocouple, wherein the control device is adapted to control the ignitor to ignite and control the gas valve to open the gas pipe, and to stop the ignitor from igniting and control the gas valve to keep the gas pipe be in an open state when the sensing voltage output from the thermocouple increases to a first voltage; then, the control device is adapted to control the gas valve to block the gas pipe when the sensing voltage output from the thermocouple decreases from higher than a second voltage to lower than the second voltage, wherein the second voltage is higher than the first voltage.
The advantage of the present invention is that through defining the sensing voltage output from the thermocouple as the first voltage for identifying the successful ignition, the ignition procedure with the ignitor could be speeded up, and the ignition time and the power consumption during the ignition could be reduced. The gas could further be blocked earlier as the second voltage, which is higher than the first voltage, is utilized for identifying the extinguished flames, thereby improving the security of the gas appliance.
The present invention will be best understood by referring to the following detailed description of some illustrative embodiments in conjunction with the accompanying drawings, in which:
The following illustrative embodiments and drawings are provided to illustrate the disclosure of the present invention, these and other advantages and effects can be clearly understood by persons skilled in the art after reading the disclosure of this specification. As shown in
The burner 20 includes at least one flame port which is adapted to burn gas to generate flames. The gas valve 22 is disposed on a gas pipe P communicating with the burner 20. The gas valve 22 is controllable to open or block the gas pipe P and regulate a gas flow supplying to the burner 20. The ignitor 24 is disposed adjacent to the flame port of the burner 20, and is controllable to generate sparks with respect to the burner 20 so as to ignite the gas output from the flame port of the burner 20. The thermocouple 26 is disposed adjacent to the burner 20, and is adapted to sense the flames and output a corresponding sensing voltage.
The control device 28 is electronically connected to the gas valve 22, the ignitor 24, and the thermocouple 26. In addition, the control device 28 is further electronically connected to a trigger which is a switch 30 as an example. The switch 30 is triggered by a user to generate a trigger signal, and outputs the trigger signal to the control device 28. The control device 28 includes an ignition circuit (not shown) to control the ignitor 24. The control device 28 is adapted to execute a control method for the gas appliance 2 of this embodiment, wherein the control method comprises the following steps, which are shown in
Step S01: receiving the trigger signal generated by the switch 30.
Step S02: controlling the ignitor 24 to ignite, and controlling the gas valve 22 to open the gas pipe P for supplying the gas to the burner 20.
Step S03: receiving the sensing voltage output from the thermocouple 26 continuously.
Referring to
Step S04: when the sensing voltage increases to a first voltage V1 (i.e., at the time t2), the control device 28 would identify that the ignition is successful, and meanwhile, the control device 28 would stop the ignitor 24 from igniting and control the gas valve 22 to keep the gas pipe P be in an open state to supply gas to the burner 20 continuously. The thermocouple 26 is continuously heated by the flames to make the sensing voltage increase from the first voltage V1 to a predetermined voltage V, wherein the predetermined voltage V is determined by a flame size (that is, the predetermined voltage V is varied depending on the gas flow rate output to the burner 20). In order to illustrate easily, in
Step S05: then, the control device 28 continuously receives the sensing voltage output from the thermocouple 26. When the flames are extinguished (i.e., at the time t3), but not because the gas is blocked by the gas valve 22, for example, the flames are extinguished by wind or due to insufficient gas flow rate, the sensing voltage output from the thermocouple 26 would decrease gradually from the predetermined voltage V which is higher than a second voltage V2 to the sensing voltage which is lower the second voltage V2 (i.e., at the time t4), and meanwhile, the control device 28 would identify that the flames are extinguished and control the gas valve 22 to block the gas pipe P. Wherein, the second voltage V2 is higher than the first voltage V1. In this embodiment, the second voltage V2 is higher than twice of the first voltage V1.
With the aforementioned steps, as comparing to the conventional gas appliance 1, the gas appliance 2 of the present invention could identify the successful ignition faster so as to reduce a time for the ignitor 24 to continuously ignite. In addition, the gas appliance 2 could block the gas earlier when the flames are extinguished abnormally, thereby preventing the gas from leaking out of the flame port of the burner 20 for a long time.
Sometimes the flames are blew by wind and lose contact with the thermocouple 26 temporarily but soon contact with the thermocouple 26 again, which makes the sensing voltage output from the thermocouple 26 become lower than the second voltage V2 in a short time but then become higher than the second voltage V2 again. Hence, the control device 28 would identify that the flames are extinguished and control the gas valve 22 to block the gas pipe P. In order to prevent the aforementioned situation, in a second embodiment, it could further include a step of controlling the gas valve 22 to block the gas pipe P until the sensing voltage is continuously lower than the second voltage V2 for a predetermined period of time such that the gas would not be blocked as the flames lose contact with the thermocouple 26 temporarily. Preferably, the predetermined period of time is within ten seconds, that is, the gas valve 22 is controllable to block the gas pipe P within ten seconds after the time t4 (i.e., at the time t5), as shown in
After step S04, a control method for the gas appliance 2 of a third embodiment further includes the following steps. The control device 28 is adapted to identify the gas flow rate, which is regulated by the gas valve 22, supplying to the burner 20 (e.g., the gas flow rate is identified according to an opening degree of the gas valve 22 or is identified by utilizing an anemometer). When the gas flow rate supplying to the burner 20 reaches a predetermined gas flow rate for a predetermined period of time (e.g., two to five minutes in this embodiment), or when a slope of the sensing voltage with respect to time decreases to a predetermined slope (that is, a temperature of the flames is stable), a voltage of the sensing voltage would be recorded and a new first voltage V1 for next ignition would be set based on the recorded voltage. The aforementioned predetermined slope is larger than or equal to zero. In this embodiment, the recorded voltage is at least divided by two to be set as the new first voltage V1. Preferably, the new first voltage V1 could be set as one value which is between one third and one fourth of the recorded voltage. Preferably, the predetermined gas flow rate is the maximum gas flow rate output from the gas valve 22. Hence, the recorded voltage would be equal to the predetermined voltage V which is shown in
Moreover, the second voltage V2 in step S05 could be set based on the recorded voltage as well. In this embodiment, the second voltage V2 is higher than half of the recorded voltage. Preferably, the second voltage V2 could be set as one value which is between two third and three fourth of the recorded voltage.
In practice, the recorded voltage could be the maximum voltage output from the thermocouple 26 in a predetermined temperature, and the predetermined gas flow rate is the gas flow rate which could enable the flames generated by the burner to reach the predetermined temperature.
Moreover, the control method of each of the aforementioned embodiments could be applied to a premixed gas appliance which includes a blower such that air and gas could be premixed and then be supplied to the burner.
According to the illustration mentioned above, through defining the sensing voltage output from the thermocouple 26 as the first voltage V1 for identifying the successful ignition, the ignition procedure with the ignitor 24 could be speeded up, and the ignition time and the power consumption during the ignition could be reduced. The gas could further be blocked earlier as the second voltage V2, which is higher than the first voltage V1, is utilized for identifying the extinguished flames, thereby improving the security of the gas appliance 2.
It must be pointed out that the embodiments described above are only some embodiments of the present invention. All equivalent structures which employ the concepts disclosed in this specification and the appended claims should fall within the scope of the present invention.
