JPH0579240U - Combustion device - Google Patents

Abstract

(57) [Summary] [Purpose] According to the type of gas used, the control range of the gas supply amount that matches the type of gas is automatically set. A proportional valve 5 is provided in a gas passage 4 for supplying fuel gas to the burner 1, and the amount of gas is controlled by controlling the opening amount of the proportional valve 5. The opening amount of the proportional valve 5 is controlled by the combustion control unit 18 of the control device 12. When the gas type to be used is set, the combustion control unit 18 automatically sets the control range suitable for the gas type, and the proportional valve 5 is controlled within the control range suitable for the gas type used.
Control the valve opening amount.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a combustion device such as a water heater or a bath cooker that variably controls a control range of a gas supply amount according to a gas type of fuel.

[0002]

[Prior Art]

 FIG. 11 shows a schematic configuration of a water heater generally known as a combustion device. In the figure, a fan 2 for air supply and exhaust is arranged on the lower side of the burner 1, and a heat exchanger 3 is arranged above the burner 1. A gas passage 4 is connected to the burner 1, and a proportional valve 5 for controlling the gas amount by the valve opening amount is provided in the gas passage 4.

A water supply pipe 6 is connected to the inlet side of the heat exchanger 3. The water supply pipe 6 has a water temperature sensor 7 for detecting a water temperature and a water flow for detecting a water flow rate of the heat exchanger 3. A quantity sensor 8 is provided. A hot water supply pipe 10 is connected to the outlet side of the heat exchanger 3, and a hot water supply temperature sensor 11 for detecting the hot water supply temperature is provided in the hot water supply pipe 10.

In this type of water heater, the maximum and minimum combustion capacities are given at the design stage. Therefore, at the shipping adjustment stage of the water heater, the proportional valve 5 corresponding to the maximum combustion capacity is opened. The dynamic current and the valve-opening drive current of the proportional valve 5 corresponding to the minimum combustion capacity are set, and the control device 12 sets the valve-opening drive current corresponding to the maximum combustion capacity as the upper limit and opens the valve corresponding to the minimum combustion capacity. Combustion control of the burner 1 is performed by variably controlling the valve opening amount of the proportional valve 5 within a control range with the valve drive current as the lower limit.

As is well known, the calorific value at the time of gas combustion varies depending on the gas species. Therefore, conventionally, the combustion capacity of the water heater is set according to the gas species used, Proportional valves that match the control range of this combustion capacity were equipped according to the combustion capacity and gas type of the water heater.

[0006]

[Problems to be solved by the device]

 However, the method of equipping the dedicated proportional valve 5 according to the combustion capacity and gas type of the water heater can be used only for the specified gas type, and when using another gas type, There was the trouble that it was necessary to replace it with a proportional valve suitable for the above, and to set the capacity, that is, to newly set the control range of the proportional valve 5.

In order to eliminate such troubles, it is considered that the use of a plurality of gas species is predicted in advance and a wide control range including all control ranges of each gas species is set in advance. Be done. For example, when the gas types used are 13A gas and 6B gas, as shown in Fig. 12, it is wider than the control range that combines the control range of the valve opening drive current of 13A gas and the control range of 6B gas. It is conceivable to set a wide control range of.

However, if such a very wide control range is set, for example, when the 13A gas is used and the tap water temperature is considerably lower than the set temperature, the controller 12 sets the tap temperature to the set temperature as much as possible. In this case, the proportional valve 5 is excessively opened by the valve opening drive current of B, which is considerably larger than the upper limit current A of the control range for the original 13 A gas, so that the heat exchanger 3 is passed through this time. There is a problem that the water is overheated and hot water with a temperature considerably higher than the set temperature comes out, resulting in a large overshoot (a phenomenon in which the temperature of the hot water becomes higher than the set temperature). Further, for example, when 6B gas is used, when the hot water temperature is higher than the set temperature, the control device 12 controls the hot water temperature to approach the set temperature within a short time. Since the proportional drive valve 5 is throttled by adding a current D which is considerably smaller than the original minimum drive current C of the above, the combustion amount of gas becomes too small this time, and it becomes considerably higher than the set temperature. There is a problem that the undershoot water with a low temperature comes out.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to perform combustion control of a plurality of gas species with a common proportional valve and without causing a large overshoot or undershoot. Another object of the present invention is to provide a combustion device capable of controlling the hot water temperature quickly and stably.

[0010]

[Means for Solving the Problems]

 The present invention is configured as follows to achieve the above object. That is, the present invention is used in a combustion apparatus in which a gas flow rate adjusting valve is provided in a gas passage that guides fuel gas to a burner, and the supply gas amount is variably controlled by controlling the opening amount of the gas flow rate adjusting valve. When a gas type is set, a valve opening amount setting section is provided for automatically setting a valve opening amount control range suitable for the gas type based on the gas type setting signal. In addition, the valve opening amount setting unit widens the predetermined amount range to the upper side of the valve opening amount corresponding to the maximum combustion capacity set as the upper limit of the valve opening amount control range to control the valve opening amount. The lower limit of the range is widened by a predetermined amount below the valve opening amount corresponding to the minimum burning capacity set as the capacity of the equipment, and set wider than the valve opening amount control range specific to the set gas type. And said bar It is also a characteristic configuration of the present invention that a slow ignition control unit is provided to slowly operate the opening of the gas flow rate adjusting valve to slowly raise the amount of gas supplied to the burner when the engine is ignited. There is.

[0011]

[Action]

 In the present invention having the above-described configuration, when the gas type is set manually or automatically during the combustion operation of the combustion device, the valve opening amount setting unit determines the set gas type according to the set gas type. Automatically sets the valve opening control range that matches the type. Then, the burner combustion amount is controlled within the set valve opening amount control range.

[0012]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. In the description of this embodiment, the same parts as those in the conventional example are designated by the same reference numerals, and the duplicated description will be omitted. FIG. 1 shows the system configuration of an embodiment of a combustion apparatus according to the present invention. The combustion apparatus of this embodiment is also shown for a water heater as in the conventional example. In this embodiment, a hot-wire anemometer 13 as a gas flow rate detecting means is provided in the gas passage 4, and a combustion control is performed by setting a control range corresponding to the gas type in the control device 12 and performing ignition control. A unique combustion control unit 18 for performing slow ignition control is sometimes provided. Other configurations are almost the same as the above-mentioned conventional example. In FIG. 1, 9 is a fan rotation sensor for detecting the rotation of the fan 2.

As shown in FIG. 2, the hot-wire anemometer 13 includes a synthetic resin hollow case 14 in which a wind velocity sensor element 15 for detecting a gas flow rate and a temperature compensating sensor element 16 are arranged. By keeping the wind speed sensor element 15 heated, the amount of heat radiation from the wind speed sensor 15 changes according to the flow velocity of the gas passing through the case 14, and this change in heat radiation amount is converted into an electrical signal. A detection signal of the gas flow rate temperature-compensated by the temperature compensation sensor element 16 is applied to the control device 12.

As shown in FIG. 3, the characteristic combustion control unit 18 of the present embodiment includes a heat amount calculation unit 20, a required gas amount setting unit 21, a memory 22, a gas type determination unit 23, and an opening unit. The valve amount setting unit 24, the valve opening amount control unit 25, and the slow ignition control unit 26 are configured. The calorie calculation unit 20 is shown in the figure with the incoming water temperature added from the incoming water temperature sensor 7, the outgoing hot water temperature added from the outgoing hot water temperature sensor 11, and the water flow rate of the heat exchanger 3 added from the running water flow sensor 8. Based on the information about the set temperature of hot water supplied from a remote controller, etc., the required heat quantity required to raise the water supply temperature to the set temperature is PID, the combination of PID and feedforward, and the desired control calculation such as feedforward. The required gas amount setting unit 21 is added with the calculation result.

Data indicating the relationship between the gas flow rate and the sensor output of the hot-wire anemometer 13 is provided in advance in the memory 22 for each type of gas used. In order to simplify the description, the case where the gas used is 13A gas and 6B gas of city gas is explained. In this case, as an example, the graph data as shown in FIG. .. For example, taking the No. 2.5 water heater as an example, the sensor output V _AL of the gas flow rate F _AL corresponding to the heat quantity of the minimum combustion capacity of 4500 Kcal / h and the heat quantity of the maximum combustion capacity of 4500 0 Kcal / h for 13 A gas. The value of the sensor output V _AH corresponding to the gas flow rate F _AH and the value of the sensor output V _A0 when the gas flow rate is zero are given. Similarly, for the 6B gas, the minimum combustion The sensor output V _BL corresponding to the gas flow rate F _BL of the capacity, the sensor output V _BH corresponding to the gas flow rate F _BH of the maximum combustion capacity, and the sensor output V _B0 when the gas flow rate is zero are respectively given. There is.

On the other hand, the gas type discriminating unit 23 automatically discriminates the gas type to be used from the level of the signal applied from the hot wire anemometer 13 and the relationship graph of the gas flow rate and the sensor output stored in the memory 22. As is well known, the heat conductivity differs depending on the type of gas, and therefore the amount of heat released from the wind speed sensor element 15 differs depending on the type of gas. Even when the flow rate is zero, the output level of the hot-wire anemometer 13 differs depending on the gas type. Utilizing this phenomenon, in this embodiment, the gas type discriminating unit 23 compares the sensor output added from the hot wire anemometer 13 with the gas flow rate at zero and the relationship graph data between the gas flow rate and the sensor output. Then, the gas type is discriminated (if the sensor output is V _A0 , it is discriminated as 13A gas, if it is V _B0 , it is discriminated as 6B gas), and the discrimination result is added to the required gas amount setting unit 21 and the valve opening amount setting unit 24. ..

The valve opening amount setting unit 24 sets the control range of the gas flow rate according to the type of gas used. The control range is set based on the gas type and the sensor output data stored in the memory 22. There are various possible ways of setting this. For example, in the case of 13A gas, the gas flow rate of the minimum combustion amount of the water heater is set as the value of the sensor output V _AL , and the gas corresponding to the maximum combustion capacity is set. The flow rate may be set as V _AH , similarly, the gas flow rate of the minimum combustion capacity may be set as V _BL and the gas flow rate corresponding to the maximum combustion capacity may be set as V _BH in the case of 6 B gas, but in this embodiment, The lower limit and the upper limit of the control range are widened by a predetermined amount, for example, 10 to 20% relative to the control range, and in the case of 13 A gas, the upper limit of the control range is given by V _AH ′ and the lower limit is given by V _AL ′. In the case of 6B gas, the upper limit of the control range is given by V _BH ′ and the lower limit is given by V _BL ′. Then, this set control range is added to the required gas amount setting unit 21 and the valve opening amount control unit 25.

The required gas amount setting unit 21 is a gas amount F required to generate the required heat amount of the heat amount calculation unit 20._GAnd calculate this F_GIs the gas flow rate F at the lower limit of the control range of the water heater_GL(13 A gas is F_AL', F for 6B gas_BL′) And the upper limit gas flow rate F_GH(F for 13A gas_AH', F for 6B gas_BHIt is judged whether it is within the range of ′) and F_GLAnd F _GH When it is within the range of, the calculated value F_GThe required gas amount F as it is_GSPAnd set F_GIs F_GLLower limit F_GLThe required gas amount F_GSPAs the value of (F_GSP= F_GL), Also F_GIs F_GHWhen it exceeds the upper limit, the upper limit F_GHThe required gas amount F_GSPAs the value of (F_GSP= F_GH) Set. Then, the required gas amount set value F_GSPIs added to the valve opening amount control unit 25.

The valve opening amount control unit 25 has a calculation unit, and sets the control range of the valve opening amount according to the gas type to be used, and within the set control range, the proportional valve 5 as a gas flow rate adjusting valve. The valve opening drive current is calculated. At the installation and construction stage of the water heater, the valve opening amount control unit 25 is given a wide valve opening amount control range including the control ranges of a plurality of gas types. For example, when 13A gas and 6B gas are assumed to be used as gas species, the control range with the upper limit including the control ranges of these gases as V _GH and the lower limit as V _GL is given in FIG. Therefore, when the water heater is actually used, the wide control range is updated and set to a control range suitable for the gas type to be used, based on the control range added from the valve opening amount setting unit 24. For example, when the gas type is 13 A gas, the original control range V _{GL to} V _GH is updated and set to V _AL ′ to V _AH ′. Similarly, when 6B gas is used, the control range is updated and set to the range of V _BL ′ to V _BH ′.

Next, the valve opening amount control unit 25 compares the required gas amount F _GSP added from the required gas amount setting unit 21 and the detected flow rate of the gas added from the hot wire anemometer 13, and the burner 1 The valve opening amount of the proportional valve 5, that is, the magnitude of the valve opening drive current applied to the proportional valve 5 is calculated by, for example, PI calculation so that the added gas flow rate becomes the required gas amount F _GSP , and the calculated valve opening drive is performed. An electric current is applied to the proportional valve 5, and the valve opening amount of the proportional valve 5 is controlled within the control range set by the control range setting unit 24 to perform the combustion operation of the burner 1.

The slow ignition control unit 26 widens the proportional band of the PI calculation formula when obtaining the valve opening drive current of the valve opening amount control unit 25 when the ignition operation state of the water heater is detected, and (or ) Increase the integration time. As a result, the valve-opening drive current applied to the proportional valve 5 at the time of ignition rises slowly, so the valve-opening operation becomes slower, and the desired slow ignition is achieved.

This embodiment is configured as described above, and its operation will be briefly described below with reference to the flowchart shown in FIG. First, immediately after the start, in step 100, it is judged whether or not the ignition is in an operating state. Except for the ignition operation, detection of the set temperature of hot water supply, detection of incoming water temperature entering the heat exchanger 3, detection of outgoing hot water temperature coming out of the heat exchanger 3, and detection of water flow rate of the heat exchanger 3. Based on these detected values, the required amount of heat required to raise the water entering the heat exchanger 3 to the set temperature is determined by the calorific value calculation unit 20 in step 105. It is calculated by a desired control calculation such as a feed forward, in this embodiment, a control calculation formula using both PID and feedforward.

Next, in step 106, the gas amount F _G required to obtain the calculated required heat amount is calculated. In step 107, it is determined whether the calculated gas amount F _G is larger than the upper limit gas amount F _GH of the control range set by the valve opening amount update setting unit 24. When F _G is larger than F _{GH, the} required gas amount F _GSP is set as the value of F _GH .

On the other hand, F_GHThan F_GWhen is small, F_GIs the lower limit gas amount in the control range F_GLIs smaller than F, and F_GIs F_GLLess than F_GLThe required gas amount F_GSPSet as the value of. F_GIs F_GLGreater than F_GHIf it is smaller than F, the gas amount F calculated in step 106_GThe required gas amount F_GSPSet as. Next, at step 112, the current gas amount F is detected by the detection signal from the hot wire anemometer 13._GI Of the detected gas amount F in step 113._GIAnd the required gas amount F set above _GSP From these values, the valve opening drive current of the proportional valve 5 is calculated by the PI calculation so that the flow rate of the gas supplied to the burner 1 becomes the required gas amount. Control.

On the other hand, when it is determined in step 100 that the slow ignition operation is to be performed, the gas amount F _GSP ′ required for the slow ignition is set in step 114. This gas amount F _GSP ′ can be given as a function of the prediction time, or it may be calculated. In step 115, the hot wire anemometer 13 detects the amount of gas F _GI currently flowing in the gas passage 4, and in step 116, the value of F _GSP ′ and F _GI causes F _GI to approach F _GSP ′. The valve opening drive current of the proportional valve 5 is calculated by the PI calculation by the valve opening amount control unit 25. At the time of this PI calculation, the slow ignition control unit 26 changes the PI calculation constant in the direction in which the proportional band of the PI calculation is wide and / or in the direction in which the integration time is long, and as a result, the PI calculation is performed slowly with respect to time. The valve-opening drive current that rises is calculated, and this valve-opening drive current is applied to the proportional valve 5, so that the supply gas amount slowly rises and the target slow ignition is performed.

In this embodiment, the calculation formula of the required gas amount setting unit 21 and the values of the upper limit F _GH and the lower limit F _GL of the control range are automatically changed to the changed gas type each time the used gas type changes. The combustion control of the burner 1 is performed through the above calculation process.

In the present embodiment, the control range for opening the proportional valve 5 is updated and set according to the type of gas used, so that the type of gas used changes. Also, without changing the proportional valve or manually changing the control range, it is possible to suitably perform the combustion control suitable for the gas type after the change.

In addition, in the present embodiment, when the control range is updated and set, the control range is set wider than the minimum and maximum ranges of the combustion capacity determined by the specifications of the water heater, so the amount of gas supplied to the burner 1 It is possible to obtain an excellent control effect that the hot water temperature of the water heater can be quickly focused on the set temperature by promptly following the required gas amount.

6 to 7 are graphs showing these effects in a comparative state with the conventional example. FIG. 6 is a graph showing the outlet heated temperature characteristic ((a) in the same figure) and the gas amount control mode ((b) in the same figure) when the amount of discharged hot water is varied as shown in (c) of the same figure. , The broken line shows the conventional example, and the solid line shows the case of this embodiment. In the conventional example, for example, when a large amount of hot water is supplied, which is close to the hot water supply capacity of the water heater, the amount of gas supplied to the burner 1 cannot exceed the upper limit of the combustion capacity of the equipment. If the hot water temperature is much lower than the set temperature, even if the gas supply amount is increased to the upper limit of the capacity of the equipment, the hot water temperature cannot be raised, and it takes a long time to reach the set temperature. However, in this embodiment, as shown in (b) of the same figure, the control range of the gas supply amount is widened to the upper side within a range where there is no overshoot larger than the upper limit of the capacity of the equipment of the water heater. Therefore, since it is possible to supply a gas amount that exceeds that capacity, the hot water temperature can be quickly raised to the set temperature even when supplying a large amount of hot water, and the hot water outlet temperature characteristics are effectively improved. There is. Moreover, even when the amount of hot water discharged is sharply reduced, the amount of gas can be reduced beyond the lower limit of the capacity of the equipment, so the amount of gas can be made to quickly follow the required amount of gas. It is possible to suppress the occurrence of overshoot and undershoot, and stabilize the hot water temperature.

FIG. 7 shows the temperature characteristics of the hot water discharge (FIG. 7A) and the gas amount control mode (FIG. 7B) when the hot water discharge amount is changed in the manner shown in FIG. In comparison with the conventional example, the broken line shows the conventional example, and the solid line shows the embodiment. For example, when the hot water supply amount is rapidly changed and the hot water supply amount is rapidly changed, the amount of gas supplied to the burner 1 must be increased accordingly. In the example, since the control range of the gas amount is limited to the lower limit and the upper limit of the capacity of the water heater, even if the gas amount is controlled to increase, the gas amount must be supplied beyond the upper limit. Therefore, there is a problem that the response of the hot water temperature cannot be speeded up. Similarly, if there is a demand for a rapid decrease in the gas supply amount from the steady combustion state, there is the problem that the response of the hot water temperature cannot be increased. On the other hand, in the present embodiment, as shown in (b) of the figure, the control range of the gas supply amount is set wider by ΔH at the upper limit and by ΔL at the lower limit than the control range of the conventional example. Therefore, for example, during steady combustion, when there is a change in the direction of rapid increase in the gas supply amount, it is possible to supply the gas supply amount that exceeds the conventional upper limit. The responsiveness of the gas supply amount also improves, and similarly, when the gas supply amount is rapidly reduced during normal combustion, the responsiveness of the gas supply amount becomes quick and sufficient control performance is achieved. Can be increased to

Further, in the present embodiment, since the ignition operation is configured to ignite slowly, the effect that the ignition operation can be smoothly performed is obtained. FIG. 8 shows this effect in comparison with the conventional example. The broken line shows the conventional example, and the solid line shows the embodiment. At the time of ignition, since the gas supply amount is raised by the normal PI operation, the initial gas flow rate at ignition becomes unstable. Becomes unstable, and if this unstable condition becomes severe, there is a problem that an ignition error will occur. On the other hand, in the present embodiment, since the slow ignition is performed, the change in the gas flow rate at the initial stage of the ignition becomes gradual, whereby the ignition can be stably and smoothly performed. Also, after the point ignition period has elapsed, the control range of the gas supply amount is set to a wide range as described above even when shifting to proportional combustion by the combined use of PID and feedforward. Response becomes quick, and the gas supply amount can be raised to the required gas amount in an extremely short time.

The present invention is not limited to the above-mentioned embodiment, and various embodiments can be adopted. For example, in the above embodiment, the hot wire anemometer 13 was used as the gas flow rate detecting means, but it is also possible to use the specific gravity float type detecting means as shown in FIG. ), A pressure sensor type means may be used. In the case of the specific gravity float type detection means, the accommodation space 31 of the float 30 is provided, and the position of the float 30 floated by the flow of gas is located on the wall side of the accommodation space 31 by a magnetic conversion type or photo coupler. The position of the gas flow rate can be detected by providing the position detecting means 32 for detecting the floating position of the float 30 with the position detecting means 30 by detecting the floating position of the float 30. Further, in the case of the pressure sensor type shown in FIG. 9B, a pressure sensor 35 is provided in the gas passage 4 between the proportional valve 5 and the burner 1, and the gas flow rate can be converted into pressure for detection. ..

Further, even when these flow rate detecting means are used, it is possible to automatically determine the gas type to be used by the output level of the flow rate detecting means. For example, when the flow rate detecting means is of a specific gravity float type, the floating position of the float 30 is different when the gas flow rate is zero or when the flow rate is zero because the gas specific gravity differs depending on the gas species. As a result, the output level changes depending on the gas type, and the gas type can be automatically discriminated by detecting this change. Further, even when a pressure sensor type is used as the flow rate detecting means, the pressure varies depending on the gas type. Therefore, by similarly analyzing the output level of the pressure sensor, it becomes possible to automatically determine the gas type. ..

In the present embodiment, the automatic discrimination of the gas type is discriminated based on the sensor output when the gas flow rate is zero, but it is discriminated based on the sensor output level when the gas is flowing at a predetermined speed. Alternatively, multiple points of sensor output may be detected at multiple gas flow positions to create a graph of the relationship between gas flow and sensor output, and the curve pattern of this graph and the graph data pattern of each gas type. It may be possible to automatically discriminate the type of gas to be used by comparing and referring to.

Further, although the gas type is automatically discriminated in the above-described embodiment, for example, a gas type to be used when a hot water heater is installed by providing a manual switch for the gas type in the control device 12 or a remote controller. The gas switch may be set by switching the manual switch according to the type.

Further, in the above-mentioned embodiment, the flow rate detecting means (the hot-wire anemometer 13 in the embodiment) is provided in the main gas passage 4, but when a low-calorie gas species and a high-calorie gas species are used, As shown in FIG. 10, it is desirable to provide a bypass passage 33 for the gas passage 4. As is well known, since the specific gravity varies depending on the gas species, there is a large difference in the gas flow rate between the low-calorie gas and the high-calorie gas. Table 1 shows the comparison data of the flow rates of these gas species.

[0037]

[Table 1]

In this table, for example, looking at the flow rate at the time of maximum combustion in the No. 24 water heater, for example, when propane gas (LP gas) is set to 1, the flow rate for 6B gas is 4.3 times. The lowest flow rate, 4C gas, is 7.5 times higher. In addition, the same ratio is obtained even when the gas flow rate at the time of minimum combustion when the water heater is No. 2.5. On the other hand, when the water heater is at the maximum combustion of No. 24, assuming that the flow rate of 13A gas is 1, the flow rate of 4C gas is 3.2 times that. In addition, the same ratio will be obtained for the No. 2.5 water heater even during minimum combustion.

As described above, since the flow rate greatly differs depending on the gas type, for example, the passage area of the gas passage 4 is set according to the flow rate of propane gas or 13A gas, and the hot wire anemometer 13 or the like is set in the gas passage 4. If propane gas or 13A gas can be detected with the flow rate detection means, the gas flow rate can be detected without any problem. However, when the low calorie gas 4C gas with a low specific gravity is used, the gas flow rate is too large and There is a problem that the gas flow rate cannot be detected because the detected value greatly deviates from the measurement range of the anemometer 13 or the like. In order to avoid this, as shown in FIG. 10, a bypass passage 33 is provided, and for example, a flow restricting means 34 such as a damper or a valve is provided in the bypass passage 33, and a low-calorie gas such as 4C gas is provided. When the seed is used, the flow restrictor 34 is opened to allow the gas to flow through both the passages 4 and 33 so that the flow rate of the gas is detected by the flow through the passage 4, and when the high calorie gas is used, the flow restrictor is used. It is possible to close the means 34 and allow all the gas to flow through the passage 4 to detect the gas flow rate. This makes it possible to detect the gas flow rate from low-calorie gas to high-calorie gas without any problem.

Further, in the above embodiment, the valve opening amount control unit 25 is previously given a wide control range of the valve opening amount including the control ranges of a plurality of gas types, and when the gas type is set, The control range was updated to match the gas type, but the wide opening control range was not given to the valve opening control unit 25 in advance, and the gas was not supplied when the water heater was first installed and installed. When the species is set, the control range suitable for the gas species may be automatically set. Even in this case, when the gas type to be used is changed thereafter, the control range is updated to match the changed gas type.

Further, in the above embodiment, the gas flow rate is detected, and the combustion control is performed by the detection signal. However, as in the case of a general water heater, the gas flow rate is not detected and the normal feed forward or PID is detected. The combustion control may be performed by a control method such as the combined use of feedforward and PID. In this case, the control range of the valve opening amount of the proportional valve 5 is set by the valve opening drive current, as has been widely done in the past. In this case as well, in the present invention, when the gas type is set, that gas is set. The control range of the valve opening drive current that matches the type will be set automatically. When setting the control range, if there is a particular request, a control range wider than the control range specific to the set gas type is set.

Further, although the proportional valve is used as the gas flow rate adjusting valve in the above-described embodiment, the gas flow rate adjusting valve may be any one as long as it can control the gas flow rate by controlling the opening amount, for example, a needle valve or a governor. Other valves such as

Further, in the above embodiment, when the valve opening control range of the gas flow rate adjusting valve (proportional valve 5) is set to a range F _{GH to} F _GL wider than the control range peculiar to the appliance, for example, the set temperature is set to A. When set to ℃, when the hot water temperature is α ℃ lower (A-α) ℃, the gas flow rate is set to the maximum F _GH for operation, but at this time, measure the time with a timer etc. If the hot water temperature does not rise to A ° C due to insufficient capacity even after continuous operation with the amount F _GH for a predetermined time, restore the control range to the original control range of the device in order to reduce the load on the device. Similarly, when the tapping temperature is α ° C higher (A + α) ° C than the set temperature of A ° C, the gas flow rate is set to the minimum F _GL and the operation is performed. If the tap water temperature does not drop to A ℃ due to excess, In order to reduce the burden on the engine, the control range may be returned to the original control range of the appliance and the combustion control may be performed. In this case, the combustion control is performed so as to bring the hot water temperature close to the set temperature by also controlling the hot water flow rate.

Further, in the above-described embodiment, the hot water supply device was described as an example of the combustion device, but the present invention is also applied to various combustion devices such as a bath heater and a gas heater.

[0045]

[Effect of the device]

 The present invention is configured such that when the gas type to be used is set, the valve opening amount control range suitable for the gas type is automatically set. Therefore, even if the gas type is different, it is suitable for the gas type. Therefore, suitable combustion control can be performed.

Further, even if the gas type is different, it is not necessary to change and adjust the proportional valve each time as in the conventional example, and there is also a gap for manually setting the capacity of the instrument each time the gas type changes. It is unnecessary and very convenient to handle.

Further, in the case where the control range of the valve opening amount is set to be wider than the power range of the device within a range where a large overshoot or undershoot does not occur, the gas supply amount is set to the required gas. The amount of gas can be quickly tracked, which improves the responsiveness of gas supply control and enables high-performance combustion control with high performance.

Further, in the case where the burner is ignited by the slow ignition, the start-up of the gas at the time of ignition can be made slow, so that the ignition operation becomes smooth and stable without ignition mistakes. Ignition can be performed.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of a combustion apparatus according to the present invention.

FIG. 2 is a configuration explanatory view of a hot-wire anemometer used in the apparatus of the embodiment.

FIG. 3 is a block configuration diagram of a control unit that constitutes the apparatus of the embodiment.

FIG. 4 is an example of graph data showing a relationship between a gas flow rate and a sensor output.

FIG. 5 is a flowchart showing the operation of the same embodiment.

FIG. 6 is a graph showing the effect of the present embodiment in a state of comparison with the conventional example.

FIG. 7 is another graph showing the effect of the present embodiment in a comparative state with the conventional example.

FIG. 8 is an explanatory view showing the slow ignition operation of the present embodiment in a comparative state with a conventional example.

FIG. 9 is an explanatory diagram showing another example of the flow rate detecting means.

FIG. 10 is an explanatory diagram of an example in which a bypass passage is provided in the gas passage.

FIG. 11 is a system diagram of a conventional general combustion device.

FIG. 12 is an explanatory diagram of a set amount of a valve opening amount control range that can be considered in order to handle a plurality of gas types.

[Explanation of symbols]

 1 burner 5 proportional valve 12 control device 18 combustion control unit 23 gas type determination unit 24 valve opening amount setting unit 25 valve opening amount control unit 26 slow ignition control unit

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Takashi Kaneko 3-4, Fukamidai, Yamato-shi, Kanagawa Prefecture, Gaster Co., Ltd. (72) Seiichi Mori, 3-4, Fukamidai, Yamato-shi, Kanagawa Prefecture, inside Gaster, Co., Ltd.

Claims (3)

[Scope of utility model registration request] 1. A combustion apparatus in which a gas flow rate adjusting valve is provided in a gas passage for guiding a fuel gas to a burner, and a supply gas amount is variably controlled by controlling an opening amount of the gas flow rate adjusting valve. Is set, the combustion device is provided with a valve opening amount setting unit that automatically sets a valve opening amount control range suitable for the gas type based on the gas type setting signal. 2. The valve opening amount control section widens a predetermined amount range above the valve opening amount corresponding to the maximum combustion capacity set as the upper limit of the valve opening amount control range to control the valve opening amount. The lower limit of the range should be set wider than the valve opening amount control range specific to the set gas type by widening the specified amount range below the valve opening amount corresponding to the minimum combustion capacity set as the capacity of the appliance. The combustion device according to claim 1, wherein the combustion device is configured as follows. 3. A slow ignition control section for slowly activating the opening of the gas flow rate adjusting valve to slowly raise the amount of gas supplied to the burner when the burner is ignited. The described combustion device.