JP2007309554A - Gas combustion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas combustion device having a function capable of accurately discriminating kinds of gas without changing a structure of a sensor chip, and performing optimal combustion control. <P>SOLUTION: In this gas combustion device 1 comprising a thermal mass flow rate sensor 11 in a fuel gas supply passage 10 to a burner 2, a main gas solenoid valve 13 is temporarily closed when flame is detected by a frame rod 15 in its ignition operation, heater electric power of the sensor 11 is operated, and the kind of gas is discriminated on the basis of a result of the operation. After the discrimination of the kind of gas, combustion is controlled according to the kind of gas on the basis of a result of the discrimination. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gas combustion apparatus, and more particularly, to an automatic gas type discrimination technique in a gas combustion apparatus provided with a thermal mass flow sensor as a fuel gas flow rate measuring means.

  Gas combustion devices that use gas as fuel (for example, water heaters and bath tubs) use a flow rate control valve that adjusts the fuel gas supply amount by varying the passage area of the gas supply path for combustion control. Has been proposed. (For example, refer to Patent Document 1).

  By the way, in such a gas combustion apparatus, a mass flow sensor is provided in the gas supply path in order to measure the flow rate of the gas. In such a mass flow sensor, a flow rate output is performed depending on the type of gas flowing in the gas supply path. Since the sensor characteristics have different values, it is necessary to specify the gas type before starting the operation of the gas combustion apparatus.

  Therefore, the applicant has proposed a method of measuring the heater voltage of the mass flow sensor and determining the gas type based on the measured value as a method of determining the gas type in such a gas combustion apparatus (Patent Document). 2).

Japanese Utility Model Publication No. 5-79240 JP 2005-16927 A

  However, the method of discriminating the gas type based on the heater voltage of the mass flow sensor as described above has the following problems, and improvement has been desired.

  That is, in this type of mass flow sensor, a platinum resistor is preferably used for the heater. However, since the sensor chip on which the heater is mounted is extremely small, the same conditions (temperature, pressure are Even when measuring the same gas type under the same conditions), the heater voltage varies from chip to chip, making it difficult to accurately determine the gas type.

  The present invention has been made in view of such conventional problems, and the object of the present invention is to accurately determine the gas type without modifying the structure of the sensor chip, and to perform optimal combustion control. It aims at providing the gas combustion apparatus provided with the function which can be performed.

  In order to achieve the above object, a gas combustion apparatus according to claim 1 of the present invention detects a surrounding temperature by means of a fuel gas supply path to a burner, a detector having a heater and temperature sensors disposed on both sides thereof. A heater voltage for detecting a voltage across the heater in a gas combustion apparatus having an ambient temperature sensor and including a thermal mass flow sensor that is controlled so that the heater temperature rise value is constant by the heater voltage Heater power for calculating power consumption in the heater based on detection means, bridge voltage detection means for detecting the heater bridge voltage of the heater, detection value by the heater voltage detection means, and detection value by the bridge voltage detection means And data indicating the relationship between the fuel gas type and the heater power when the fuel gas flow rate is a predetermined flow rate. Gas type determination for comparing the storage means and the calculated value calculated by the heater power calculation means when the fuel gas is at the predetermined flow rate and the data stored in the storage means to determine the gas type of the fuel gas Means.

  That is, in the gas combustion apparatus according to claim 1, the thermal mass flow sensor disposed in the fuel gas supply path to the burner is configured so that the temperature rise value of the heater is constant, in other words, the heater power Is configured to control the bridge voltage Vb of the heater bridge so that is constant. In determining the gas type, the power consumed by the heater (heater power) is calculated based on the heater voltage and the bridge voltage of the heater bridge, and the calculation result is compared with data stored in advance. The gas type of the gas is determined. That is, according to the first aspect of the present invention, the determination of the gas type is performed based on the heater power that is kept constant regardless of the variation of the heater resistance (heater voltage), not the heater voltage that varies greatly due to the production variation. Therefore, the gas type determination can be performed accurately.

  The gas combustion apparatus according to claim 2 is characterized in that the gas type discrimination by the gas type discrimination means is executed when the flow rate of the fuel gas to the burner is a constant flow rate including zero. That is, in the gas combustion apparatus according to claim 2, since the gas type determination of the fuel gas described above is performed when the flow rate is a constant flow rate including zero, for example, the fuel gas supply path is filled with the fuel gas Thus, since the gas type determination can be performed by stopping the flow of the fuel gas, it is possible to avoid an erroneous determination of the gas type due to a change in the flow rate of the fuel gas.

  According to a third aspect of the present invention, there is provided a gas combustion apparatus comprising: ignition means for igniting the burner; ignition detection means for detecting ignition to the burner; and fuel configured to cut off supply of fuel gas to the burner When the ignition detecting means detects ignition during the ignition operation by the ignition means, the fuel gas supply is shut off by the fuel cutoff means, and the gas type discrimination of the fuel gas is performed by the gas type discrimination means. It is executed.

  That is, according to the gas combustion device of claim 3, since the fuel gas supply is shut off after detecting the ignition by the ignition means and the gas type is determined, the fuel gas supply path is filled with the fuel gas, That is, since the gas type can be determined in a state where air or the like is not mixed, the gas type can be determined accurately.

  The gas combustion apparatus according to claim 4 is characterized in that the discrimination of the gas type by the gas type discrimination means is executed after the combustion of the burner is stopped. That is, in the gas combustion apparatus of claim 4, since the gas type is determined after the combustion of the burner is stopped, for example, when the gas combustion apparatus is a water heater, the gas type determination is performed at the end of the hot water supply operation. As in the third aspect, the gas type determination can be performed accurately.

  According to a fifth aspect of the present invention, there is provided a gas combustion apparatus comprising combustion control means for performing combustion control according to the gas type based on the determination result of the gas type determination means. That is, in the gas combustion apparatus according to the fifth aspect, since the combustion control according to the gas type is performed after the gas type is determined, the optimal combustion control according to the gas type can be performed.

  According to the present invention, since the gas type of the fuel gas is automatically discriminated by the gas type discriminating means, it is not necessary to perform a gas type setting operation by a human, and the gas type discrimination of the fuel gas can be performed quickly and reliably. . In addition, since the gas type discrimination by the gas type discrimination means is performed based on the heater power calculated based on the heater voltage and the bridge voltage of the heater bridge, it is affected by the production variation of the heater resistance (heater voltage). Therefore, it is possible to accurately determine the gas type.

  In addition, since the gas type determination by the gas type determination means is performed by interrupting the supply of the fuel gas after the ignition is detected during the ignition operation to the burner, an erroneous determination due to mixing of gas other than the fuel gas is avoided and accurate. The gas type can be determined.

  Furthermore, by performing the gas type discrimination during the ignition operation, it is possible to automatically cope with the change of the gas type. In addition, by providing combustion control means for performing combustion control suitable for the gas type based on the determination result of the gas type determination means, a user-friendly gas combustion apparatus can be provided.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a case where the gas combustion apparatus of the present invention is applied to a water heater. As shown in the figure, the water heater 1 includes a burner 2 that uses gas as fuel in its main body, and a heat exchanger 3 that is configured to be heated by the burner 2 is provided above the burner 2. Further, a blower fan 4 for supplying air to the burner 2 is provided below the burner 2.

  A water supply pipe 5 is connected to the water inlet side of the heat exchanger 3, and a hot water discharge pipe 6 is connected to the hot water side. The water supply pipe 5 is provided with an incoming water temperature sensor (incoming water temperature detecting means) 7 for detecting an incoming water temperature Ta to the heat exchanger 3 and a water amount sensor (incoming water amount detecting means) 9 for detecting an incoming water amount Q. ing. The tapping pipe 6 is provided with a tapping temperature sensor (tapping temperature detecting means) 8 that detects a tapping temperature Tb of hot water heated by the heat exchanger 3.

  On the other hand, a gas pipe 10 for supplying fuel gas to the burner 2 is connected to the burner 2. The gas pipe 10 is connected to a gas supply source (for example, a gas pipe for supplying city gas for city gas, a gas cylinder for propane gas, etc.), and constitutes a fuel gas supply path to the burner 2. is doing.

  The gas pipe 10 includes a gas flow rate sensor 11 for detecting the flow rate V of the fuel gas, a gas flow rate control valve 12 for adjusting the flow rate V of the fuel gas supplied to the burner 2, and a fuel gas to the burner 2. An original gas solenoid valve (fuel cutoff means) 13 configured to be able to shut off the supply of is provided.

  In this embodiment, a thermal mass flow sensor that detects the mass flow rate of the fluid flowing in the gas pipe 10 is used as the gas flow sensor 11. As shown in FIG. 2 (a), the gas flow sensor 11 is a heater that raises the temperature of a fluid to be measured at a constant temperature on a base 101 having an insulating film layer formed on the surface of a silicon chip as a detector. The heater resistance Rh as a temperature sensor, the upstream temperature sensor resistance Ru and the downstream temperature sensor resistance Rd as temperature sensors disposed on both upstream and downstream sides in the fluid passage direction across the heater resistance Rh, and the upstream temperature An ambient temperature sensor resistance Rr as a temperature sensor for detecting an ambient temperature (in other words, a fluid temperature) is disposed further upstream of the sensor resistance Ru.

  Each of these resistors Rh, Ru, Rd, Rr is a resistor whose resistance value changes according to temperature (for example, platinum resistor). Although not shown, the silicon at the center of the base 101 where the heater resistance Rh and the upstream and downstream temperature sensor resistances Ru and Rd are provided is removed by etching or the like, and these resistors and the base 101 are heated. Insulated diaphragm structure.

  By the way, the specific configuration (particularly, the configuration of the temperature detection circuit using the temperature sensor resistances Ru and Rd) and the operation principle of the thermal mass flow sensor configured as described above are well known, and a detailed description thereof will be given here. Although not shown, in this type of gas flow sensor 11, the heater resistance Rh and the ambient temperature sensor resistance Rr constitute a bridge circuit together with the resistances R1 and R2 as shown in FIG. The temperature of (heater resistance Rh) is controlled to be higher than the ambient temperature by a predetermined temperature (heater control circuit).

  Specifically, the heater control circuit connects the connection point between the resistor R1 and the heater resistor Rh to the non-inverting input terminal of the operational amplifier OP, and connects the connection point between the resistor R2 and the ambient temperature sensor resistor Rr to the operational amplifier. It is configured by connecting to the inverting input terminal of OP and connecting the output terminal of the operational amplifier OP to the connection point of the resistors R1 and R2 via a voltage control element such as a transistor (not shown). A resistor R3 is connected to both ends of the heater resistor Rh. Here, each of the resistors R1 to R3 is a resistor whose resistance value has little production variation (for example, a carbon film resistor or a solid resistor is preferably used).

  In the heater control circuit configured as described above, the heater voltage Vh is controlled so that the heater resistance Rh supplements the heat taken away by the surrounding gas. That is, since the temperature of the heater resistance Rh is proportional to the heater power Ph consumed by the heater resistance Rh, the heater control circuit is configured so that the heater power Ph becomes constant in order to keep the temperature of the heater resistance Rh constant. The bridge voltage Vb is controlled.

  Thereby, for example, when a gas (gas) with high thermal conductivity is in contact with the heater resistance Rh, the amount of heat diffused from the heater to the gas side is large (a lot of heat is taken away by the surrounding gas). The heater control circuit adjusts the bridge voltage Vb so as to maintain the heater temperature at a predetermined temperature (adjusts the heater voltage Vh higher). On the other hand, when the heater resistance Rh is in contact with a gas (gas) having low thermal conductivity, the diffusion of heat to the gas side is small, so the bridge voltage Vb is adjusted so as to reduce the heater voltage.

  As will be described later, in the present invention, since the gas type is discriminated by making use of the control characteristics of the heater control circuit, the gas flow rate sensor 11 detects the voltage Vh across the heater resistance Rh. The heater voltage detecting means 111 for detecting the heater bridge voltage and the bridge voltage detecting means 112 for detecting the heater bridge voltage Vb are provided (see FIG. 3).

  The gas flow rate control valve 12 is constituted by a proportional valve that controls the flow rate of the fuel gas by operating the valve body and changing the opening area of the valve seat, such as a needle valve. That is, the amount of gas supplied to the burner can be adjusted by changing the cross-sectional area (passage area) of the fuel gas supply path by adjusting the opening of the valve.

  The original gas solenoid valve 13 is composed of an open / close solenoid valve that switches between opening and closing the gas supply path, and is disposed upstream of the gas flow sensor 11 as shown in the figure, and the fuel gas of the burner 2 is closed by closing the valve body. It is comprised so that supply can be interrupted | blocked.

  In the vicinity of the burner 2, an igniter (ignition means) 14 for igniting the burner 2 and a frame rod (ignition detection means) 15 for detecting ignition (presence or absence of flame) to the burner 2 are provided. Yes. In addition, since these structures and arrangement | positioning are well-known, detailed description is abbreviate | omitted.

  The controller 16 constitutes a control means for controlling the operation of each part of the water heater 1, and specifically, for executing various controls and processes such as combustion control and gas type discrimination process described later. A microcomputer is the main part. In the present embodiment, when the controller 16 is configured based on its function, as shown in FIG. 3, the combustion control means 20, the heater power calculation means 21, the gas type determination means 22, and the storage means 23 Consists of

  As shown in FIG. 1, the controller 16 outputs signals from the water temperature sensor 7, the hot water temperature sensor 8, the water amount sensor 9, the gas flow rate sensor 11, the frame rod 15 and the like as indicated by broken lines in the figure. Connected through a line. Similarly, the controller 16 is connected to the blower fan 4, the gas flow rate control valve 12, the original gas solenoid valve 13, the igniter 14 and the like through signal lines indicated by broken lines, and control signals for controlling the operation thereof. Can be output.

  Therefore, the operation of the water heater 1 configured as described above will be described with reference to FIGS. 3 and 4. 3 shows a functional block diagram of the water heater 1 according to the present invention, and FIG. 4 is a flowchart showing an example of the procedure of the gas type discrimination process. In FIG. 3, reference numeral 30 denotes a remote controller (operating device) for the water heater 1.

  When the operation start operation is performed with the remote controller 30 and the tip plugs are opened in this state, and water flow exceeding the minimum operating water flow amount occurs in the water heater 1 (see step S1 in FIG. 4), the combustion control means 20 of the controller 16 Thus, the ignition operation is started (see step S2 in FIG. 4).

  This ignition operation refers to a series of processes for opening the original gas solenoid valve 13 and the gas flow rate control valve 12 to operate the igniter 14. This ignition operation is repeated until flame is detected by the frame rod 15. (See step S3 in FIG. 4). This is because even when both the original gas solenoid valve 13 and the gas flow rate control valve 12 are opened when the gas pipe 10 is filled with air (for example, after the completion of the gas pipe connection work). This is because the amount of fuel gas required for ignition does not come out of the burner 2, so that the ignition operation is performed until the amount of fuel gas required for ignition comes out of the burner 2.

  When the flame (ignition) in the burner 2 is detected by the frame rod 15, the controller 16 next executes a process for closing the original gas solenoid valve 13 (see step S4 in FIG. 4). The supply of the fuel gas to 2 is stopped, and the gas type determination process (the processes of steps S5 and S6 in FIG. 4) is started. That is, after the fired flame is extinguished, the gas type determination process (the processes in steps S5 and S6 in FIG. 4) is executed.

  Here, the reason why the ignited flame is once extinguished and the next process is performed is that the fuel gas is filled in the gas pipe 10 when the burner 2 is ignited. Is closed to fill the gas pipe 10 with the fuel gas and stop the gas flow in that state to determine the gas type.

When the closing process of the original gas solenoid valve 13 is completed, the controller 16 next detects the detected value (heater voltage Vh) by the heater voltage detecting means 111 and the detected value (bridge voltage Vb) by the bridge voltage detecting means 112. Based on the above, the heater power calculation means 21 calculates the heater power Ph. Specifically, the heater power calculation means 21 calculates the heater power Ph using the following mathematical formula (see step S5 in FIG. 4).
Ph = [(Vb−Vh) / r1−Vh / r3] × Vh

  Here, r1 and r3 in this equation indicate the resistance values of the resistors R1 and R3 of the heater control circuit, respectively. The resistance values of the resistors R1 and R3 are stored in the heater power calculation means 21 in advance as specified values.

  When the heater power Ph in the heater control circuit of the gas flow sensor 11 is calculated in this way, the calculation result is then input to the gas type discrimination means 22. Then, in the gas type discriminating means 22, the value of the heater power Ph obtained in this way and the data stored in the storage means 23 in advance (specifically, the gas type of the fuel gas and the heater power) The gas type is discriminated by comparing with the reference data indicating the relationship. That is, it is determined that the gas of the gas type that shows the same value as the value of the heater power Ph measured in step S5 in FIG. 4 is supplied.

  FIG. 5 shows an example of such data. Specifically, the data shown in FIG. 5 represents the heater power on the vertical axis and the gas type on the horizontal axis. Here, the heater power data for each gas type when the flow rate is zero is stored. Yes. That is, in the present embodiment, the original gas solenoid valve 13 is closed in step S4 in FIG. 4 (that is, the flow rate in the gas pipe 10 is made zero), and the heater power Ph of the gas flow rate sensor 11 is calculated. Since it is configured, the data stored in the storage means 23 uses the same conditions, that is, data for each gas type when the flow rate is zero.

  In addition, about this point, if the gas flow rate at the time of calculating the heater power Ph and the data stored in the storage unit 23 can be compared (if both have the same flow rate), they are stored in the storage unit 23. It is also possible to store data when the gas flow rate is a predetermined flow rate other than zero as data. That is, the same condition (flow rate) is set such that the flow rate of the fuel gas is set to a constant flow rate (predetermined flow rate) by the gas flow rate control valve 12 without closing the original gas solenoid valve 13 in step S4 in FIG. It is also possible to store the data acquired under と し て as comparison data.

  Further, FIG. 5 shows a case in which data of seven types of fuel gases, 13A-0, 13A-1, 12A-3, air propane, 13A-2, C3H8, and C4H10, are stored as gas types. Of course, it is possible to store data of other gas types as data of the gas types to be stored in the storage means 23.

  When the gas type is determined in step S6 in FIG. 4, thereafter, the combustion control means 20 normally uses a combustion control table (control table) suitable for the gas type based on the result of the gas type determination. Is started (see step S7 in FIG. 4).

  That is, the combustion control means 20 performs the ignition operation again, and the target burner is determined from the target temperature To, the incoming water temperature Ta, and the incoming water amount Q so that hot water can be discharged at the target temperature To set by the remote controller 30. Among the control tables provided for each gas type (the table showing the correlation between the output (gas flow rate) from the sensor output circuit 113 of the flow rate sensor 11 and the calorific value). Then, a control table corresponding to the gas type obtained by the gas type discrimination is selected, and the valve opening degree of the gas flow rate control valve 12 is adjusted and controlled so that the target calorific value is obtained in the burner 2. Along with this, the rotational speed of the blower fan 4 is controlled so that an optimal combustion state is obtained by the burner 2.

  As described above, in the water heater of the present invention, the gas type discrimination means automatically discriminates the gas type of the fuel gas at the time of ignition operation, so that the gas type setting operation or the like by a person is not required quickly and reliably. Species determination can be performed. In particular, according to the present invention, the gas type is determined based on the heater power Ph when determining the gas type, so that it is possible to prevent an erroneous determination of the gas type due to production variations in the heater resistance Rh.

  That is, in the conventional gas type determination based on the heater voltage Vh, there is a possibility that the heater voltage Vh varies with the production variation of the heater resistance Rh, which may cause an erroneous determination of the gas type. The electric power Ph is kept constant by the heater control circuit regardless of the variation of the heater resistance Rh (the heater voltage Vh and the bridge voltage Vb are adjusted), so that the conventional erroneous determination problem does not occur. In addition, in the formula for calculating the heater power Ph (the formula of Ph = [(Vb−Vh) / r1−Vh / r3] × Vh), the calculation of the heater power Ph may be erroneous (causes a calculation error). The resistance values r1 and r3 are both resistors R1 and R3, which use resistors with little production variation (small errors), so that the heater power Ph can be accurately calculated, and there is little misjudgment of gas type. .

  In addition, since the calculation of the heater power Ph requires only about 20 milliseconds, the above-described processing from step S1 to step S6 in FIG. 4 is almost the same as the ignition operation in a general water heater. The water heater user can use the water heater normally without being aware that the gas type determination is being performed.

  Further, after the ignition to the burner 2 is confirmed, the combustion is temporarily stopped and the gas type determination is performed. Therefore, the gas type determination can be performed in a state where the gas gas is filled in the gas pipe 10, and a gas other than the fuel gas ( Misjudgment due to air) can be avoided, and the gas type can be accurately determined.

  Further, when the gas type of the fuel gas is discriminated by the controller 16 in this way, in this embodiment, the gas type discrimination result is displayed on the display unit provided in the main body of the hot water heater 1 or the remote controller 30. Configured.

  6A shows a case where the display means is provided on the remote controller 30, and FIG. 6B shows a case where the display means is provided on the front surface of the main body of the water heater 1.

  That is, FIG. 6A shows a case where the display unit 31 of the remote controller 30 is used as the display means, and in this case, the gas type discrimination result is displayed in characters at a predetermined position of the display unit 31 of the remote controller 30. (In the illustrated example, the case where the gas type is “13A” is displayed) is configured. FIG. 6B shows a case where a display unit 32 for gas type display is provided on the front surface of the main body of the water heater 1 as the display means. In the example shown in FIG. 6B, the display unit 32 includes a plurality of indicator lamps such as light emitting diodes for each gas type (in the example shown, an indicator lamp 32a indicating "LP gas" and an indicator lamp 32b indicating "13A gas"). 2), and an indicator lamp indicating the corresponding gas type is turned on by gas type discrimination.

  As described above, in this embodiment, since the gas type discrimination result is displayed by the display means, the contractor or the user can visually check the gas type supplied to the fuel gas supply path. Easy to find use.

  Note that the above-described embodiments merely show preferred embodiments of the present invention, and the present invention is not limited to these, and various design changes can be made within the scope thereof.

  For example, in the above-described embodiment, the determination of the gas type is performed during the ignition operation. However, for example, the gas type determination process (the processes of steps S5 and S6 in FIG. 4) is performed after the combustion is stopped. You can also. Moreover, the gas type determination at the time of the ignition operation described above can be performed only at the time of construction of the gas combustion apparatus, or can be performed at every ignition operation after the construction. Further, it is possible to make a gas type determination every predetermined time.

  In the above-described embodiment, the case where the so-called flow control type gas flow control valve 12 is used as the valve device for adjusting the fuel gas supply amount has been described. The present invention is also applicable to a water heater using a pressure control type valve device.

  In the above-described embodiment, the original gas electromagnetic valve 13 is used as the fuel cutoff means. However, if the flow of the fuel gas in the gas pipe 10 can be stopped, another valve device (for example, the gas flow control valve 12). May be used.

  Moreover, although the case where this invention was applied to the water heater was shown in embodiment mentioned above, this invention is applicable also to gas combustion apparatuses other than a water heater (for example, a bathtub, a gas stove, etc.).

  Moreover, although the case where the display means for displaying the gas type is provided on the front surface of the main body of the remote controller or the water heater 1 is shown in the above-described embodiment, when the display unit 31 of the remote controller 30 is used, for example, the display unit is normally used. 31 does not display the gas type, but is configured to display by a predetermined operation of the operation switch, or even if it is provided in the main body of the water heater 1, the position of the display means and the display mode The design can be changed as appropriate.

It is explanatory drawing which shows schematic structure of the water heater to which the gas combustion apparatus which concerns on this invention is applied. It is explanatory drawing of the thermal mass flow sensor used for the water heater, Comprising: Fig.2 (a) is a schematic structure of the detection part of the sensor, FIG.2 (b) is an example of the heater control circuit of the sensor Show. It is a functional block diagram explaining the function of the water heater. It is a flowchart which shows an example of the gas type discrimination | determination procedure of the water heater. FIG. 5 is a diagram showing an example of gas type discrimination data used in the gas type discrimination procedure of FIG. FIGS. 6A and 6B are explanatory views showing a mode of displaying the gas type discrimination result on the display means. FIG. 6A shows a case where the display means is provided in the remote control 30, and FIG. 6B shows the display means as a water heater. 1 shows the case of being provided on the front surface of the main body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water heater 2 Burner 3 Heat exchanger 4 Blower fan 5 Water supply pipe 6 Hot water outlet pipe 7 Water inlet temperature sensor 8 Hot water temperature sensor 9 Water quantity sensor 10 Gas pipe 11 Gas flow sensor 12 Gas flow control valve 13 Original gas solenoid valve )
14 Igniter (ignition means)
15 Frame rod (ignition detection means)
16 controller 20 combustion control means 21 heater power calculation means 22 gas type determination means 23 storage means 30 remote control 111 heater voltage detection means 112 bridge voltage detection means

Claims (5)

The fuel gas supply path to the burner has a heater, a detection unit having temperature sensors arranged on both sides thereof, and an ambient temperature sensor for detecting the ambient temperature, and the heater voltage has a constant temperature rise value. In a gas combustion apparatus equipped with a thermal mass flow sensor that is controlled to be
Based on a heater voltage detecting means for detecting a voltage across the heater, a bridge voltage detecting means for detecting a heater bridge voltage of the heater, a detected value by the heater voltage detecting means and a detected value by the bridge voltage detecting means. Heater power calculation means for calculating power consumption in the heater, and storage means for storing data indicating the relationship between the gas type of the fuel gas and the heater power when the flow rate of the fuel gas is a predetermined flow rate, Gas type discriminating means for discriminating the gas type of the fuel gas by comparing the calculated value calculated by the heater power calculating means when the fuel gas is at the predetermined flow rate and the data stored in the storage means. A gas combustion apparatus characterized by that. The gas combustion apparatus according to claim 1, wherein the gas type discrimination by the gas type discrimination means is executed when the flow rate of the fuel gas to the burner is a constant flow rate including zero. Ignition means for igniting the burner, ignition detection means for detecting ignition to the burner, and fuel cutoff means configured to be able to cut off the supply of fuel gas to the burner,
During the ignition operation by the ignition means, when the ignition detection means detects ignition, the fuel cutoff means cuts off the supply of fuel gas, and the gas type discrimination means executes the gas type discrimination of the fuel gas. The gas combustion apparatus according to claim 1 or 2. The gas combustion apparatus according to any one of claims 1 to 3, wherein the gas type discrimination by the gas type discrimination means is executed after the combustion of the burner is stopped. The gas combustion apparatus according to any one of claims 1 to 4, further comprising combustion control means for performing combustion control in accordance with a gas type based on a determination result of the gas type determination means.

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