Combustion equipment

Abstract

To provide a combustor that can easily detect reduction of an LP gas residual amount to issue a notification on the arrival of replacement timing of a gas cylinder.SOLUTION: A combustor (10) that burns LP gas filled in a gas cylinder as fuel in a combustion unit, has control means (6) that controls combustion operation so that a combustion output becomes a target output based on a preset operation table, and output detection means (18, 13, 16) of detecting the combustion output. When the combustion output detected by the output detection means (18, 13, 16) is higher than the target output by a reference value or more, the control means (6) issues a notification on reduction in an LP gas residual amount of the gas cylinder.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a combustion device that uses LP gas as fuel. [Background technology]

[0002] Conventionally, combustion devices that burn fuel gas have been installed in hot water heaters that use the heat of combustion, for example. Fuel gas can be either city gas, which is supplied from a supplier via gas pipelines, or LP gas, which is filled in gas cylinders that the supplier provides to each user.

[0003] Because the amount of LP gas that can be filled into a gas cylinder is limited, it is necessary to replace the gas cylinder when the remaining amount is low. For this reason, LP gas suppliers regularly check the remaining amount and replace gas cylinders as necessary to prevent running out of fuel, but this places a heavy burden on inspectors as they have to visit each and every gas cylinder location.

[0004] For this reason, a method is known in which the remaining amount of a gas cylinder is managed based on the weight of the gas cylinder, the supply flow rate of LP gas, temperature, etc., as disclosed in Patent Document 1. Also, in a fuel cell that reforms LP gas and uses it to generate electricity, a technique is known in which the supply flow rate of LP gas to a reformer is controlled based on the relationship between the residual pressure of the gas cylinder and the butane concentration in the LP gas so that the amount of hydrogen gas after reforming is constant, as disclosed in Patent Document 2. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-138325 [Patent Document 2] Patent No. 4314942 Summary of the Invention [Problem to be solved by the invention]

[0006] However, Patent Document 1 requires a device to measure the weight of the gas cylinder, which makes its implementation costly and difficult. Therefore, it is conceivable to detect the remaining amount of gas in a gas cylinder based on the relationship between the remaining pressure in the gas cylinder and the butane concentration in the LP gas, as in Patent Document 2, but there are cases where it is not possible to obtain the remaining pressure from the gas meter. Furthermore, since it is sufficient to know when it is time to replace the gas cylinder, there is no need to constantly monitor the remaining amount of gas in the gas cylinder as in Patent Document 2.

[0007] An object of the present invention is to provide a combustion device that can easily detect a decrease in the remaining amount of LP gas and notify the user that it is time to replace the gas cylinder. [Means for solving the problem]

[0008] The combustion device of the present invention, which burns LP gas filled in a gas cylinder as fuel in a combustion section, comprises a control means for controlling combustion operation so that combustion output becomes a target output based on a preset operation table, and an output detection means for detecting the combustion output. A combustion fan that supplies combustion air to the combustion section and the control means comprises: When the combustion operation is controlled based on the operation table and adjusted to the target output, if the rotation speed of the combustion fan is reduced by a certain amount or more from a reference rotation speed, it is determined that the combustion output has increased by a reference value or more relative to the target output, In this case, a notification is given that the amount of LP gas remaining in the gas cylinder is low.

[0009] According to the above configuration, the control means of the combustion device notifies the user that the remaining amount of LP gas in the gas cylinder is decreasing if the combustion output exceeds a reference value relative to the target output when the combustion operation is performed based on the operation table. As the remaining amount of LP gas in the gas cylinder decreases and the time for replacement approaches, the proportion of butane, which has a large calorific value relative to the main component propane, increases. Therefore, the combustion output increases compared to combustion operation based on the operation table. Therefore, the control means can detect that the remaining amount of LP gas is decreasing by detecting the combustion output using the output detection means, and by notifying the user that the time for gas cylinder replacement has arrived, the control means can prompt the user to replace the gas cylinder.

[0011] Furthermore, as a supplementary explanation,When adjusting the combustion output to reach the target output, if the rotation speed of the combustion fan is reduced by more than a certain amount from the reference rotation speed set in the operation table in order to reduce the combustion output, the combustion output With respect to the target output Therefore, it is possible to notify the user of a decrease in the amount of LP gas remaining, which would cause the combustion output to increase by more than the reference value, and to prompt the user to replace the gas cylinder.

[0012] Claim 2 The combustion device of the invention is In a combustion device in which LP gas filled in a gas cylinder is used as fuel and combusted in a combustion section, the device has a control means for controlling combustion operation so that combustion output becomes a target output based on a preset operation table, and a gas proportional valve as an output detection means for detecting the combustion output, which adjusts the supply flow rate of LP gas; when the control means controls the combustion operation based on the operation table and adjusts it to become the target output, if the opening of the gas proportional valve is reduced by a certain amount or more from the reference opening, the control means determines that the combustion output has increased by more than a reference value relative to the target output, and in this case issues a warning that the remaining amount of LP gas in the gas cylinder is low. It is characterized by the following. According to the above configuration, when performing combustion operation based on the operation table and adjusting the combustion output to the target output, if the opening of the gas proportional valve is reduced by more than a certain amount from the reference opening set in the operation table in order to reduce the combustion output, the combustion output With respect to the target output Therefore, it is possible to notify the user of a decrease in the amount of LP gas remaining, which would cause the combustion output to increase by more than the reference value, and to prompt the user to replace the gas cylinder. [Effects of the Invention]

[0013] According to the combustion device of the present invention, it is possible to easily detect a decrease in the remaining amount of LP gas and to notify the user that it is time to replace the gas cylinder. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram showing a water heater equipped with a combustion device according to an embodiment of the present invention; [Figure 2] 10 is an example of an operation table in which conditions for combustion operation are set. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, the mode for carrying out the present invention will be described based on examples. [Example]

[0016] A combustion apparatus that burns LP gas as fuel will be described below, taking a water heater having this combustion apparatus as an example. 1, water heater 1 has combustion device 10, heat exchanger 3 that heats hot water using the combustion heat of combustion device 10, water supply unit 4 that supplies clean water to heat exchanger 3, hot water outlet unit 5 that adjusts the temperature of the hot water heated in heat exchanger 3 and outputs the adjusted temperature, control unit 6 (control means) that controls the combustion operation of combustion device 10 and the temperature adjustment of hot water outlet unit 5, and operation terminal 6a. Operation terminal 6a has an operation switch and a display unit for setting the target hot water temperature of water heater 1, for example, and is connected to control unit 6.

[0017] The combustion device 10 has a combustion section that burns the fuel LP gas and is composed of multiple combustion stages 11a to 11d, and is equipped with a gas supply section 12 that supplies LP gas to the combustion section, a combustion fan 13 that supplies combustion air to the combustion section, and a can body case 15 that houses the combustion section and directs the combustion exhaust gas from the LP gas combustion to an exhaust port 14.

[0018] The gas supply unit 12 includes a gas passage 12a, a gas passage on-off valve 12b that opens and closes the gas passage 12a, a gas proportional valve 16 that adjusts the LP gas supply flow rate, and multiple combustion stage on-off valves 17a-17d that switch the supply of LP gas to the multiple combustion stages 11a-11d on and off. The combustion device 10 can adjust the combustion output from maximizing the combustion output by combusting all of the multiple combustion stages 11a-11d to minimizing the combustion output by combusting only the combustion stage 11a. By adjusting the opening of the gas proportional valve 16, the combustion output can be finely adjusted even with the same number of combustion stages. A flame temperature sensor 18 that detects the temperature of the flame in this combustion unit is disposed above the combustion stage 11a.

[0019] The rotation speed of combustion fan 13 is adjusted by control unit 6 to adjust the flow rate of combustion air supplied according to the combustion output. A can body temperature sensor 15a is provided on the outside of can body case 15, and if this can body temperature sensor 15a detects an abnormal temperature rise (for example, a rise of 50°C or more), control unit 6 will stop combustion to ensure safety.

[0020] The water supply section 4 includes a water supply passage 4a that supplies clean water to the heat exchange section 3, a water supply temperature sensor 4b that detects the temperature of the clean water (water supply temperature), and a water supply flow rate sensor 4c that detects the water supply flow rate of the clean water supplied to the heat exchange section 3.

[0021] The hot water outlet section 5 has a hot water outlet passage 5a that supplies hot water heated in the heat exchange section 3 to the outside, a bypass passage 7a that branches off from the water supply passage 4a and is connected to the hot water outlet passage 5a to supply clean water from the water supply passage 4a to the hot water outlet passage 5a, and a flow rate adjustment valve 7b that adjusts the flow rate of clean water in the bypass passage 7a. The hot water outlet passage 5a is equipped with a first hot water outlet temperature sensor 5b that detects the temperature of the hot water heated in the heat exchange section 3, and a second hot water outlet temperature sensor 5c that detects the temperature of the hot water that has been mixed with clean water from the bypass passage 7a and adjusted in temperature.

[0022] When the feedwater flow rate sensor 4c detects a flow rate equal to or greater than a predetermined flow rate, the control unit 6 sets the target output for the combustion operation of the combustion device 10 based on the feedwater flow rate, feedwater temperature, and target hot water temperature. Then, based on an operation table for combustion operation stored in the control unit 6, such as that shown in Fig. 2, the control unit 6 sets the combustion stage to be burned, the opening of the gas proportional valve 16, and the rotation speed of the combustion fan 13, and starts the combustion operation.

[0023] The operation table defines reference operating conditions for combustion operation according to the target output, such as the reference number of combustion stages, the reference opening of the gas proportional valve 16, the reference rotation speed of the combustion fan 13, and the reference flame temperature of the combustion section. The reference operating conditions are set in advance based on combustion experiments in which LP gas of a predetermined composition is burned, so that the higher the target output, the higher the number of combustion stages, the opening of the gas proportional valve 16, the rotation speed of the combustion fan 13, and the flame temperature of the combustion section. The LP gas of the predetermined composition is, for example, 90 mol% propane and 10 mol% butane, but is not limited to these.

[0024] LP gas is a liquefied mixture of gases containing propane as the main component and hydrocarbons such as butane, and is filled in a gas cylinder. The LP gas is supplied from this gas cylinder to the combustion device 10. Since the amount of LP gas that can be filled into a gas cylinder is limited, gas cylinders are replaced to prevent the fuel from running out.

[0025] Propane has a lower boiling point than butane and therefore vaporizes more easily, so when there is a lot of LP gas remaining in the gas cylinder, the proportion of propane in the supplied LP gas is high. On the other hand, as the amount of LP gas remaining in the gas cylinder decreases, the proportion of propane decreases and the proportion of butane increases, even if the LP gas supply flow rate remains the same.

[0026] Vaporized butane generates more heat during combustion than the same amount (volume) of vaporized propane, so if the LP gas supply flow rate is constant, the less the remaining LP gas amount, the higher the combustion output of the combustion device 10. Therefore, the control unit 6 determines that the remaining LP gas amount is low by detecting an increase in this combustion output above a reference value (for example, an increase of 20% or more) using the output detection means, and notifies the user of the low remaining amount to prompt the user to replace the gas cylinder.

[0027] Since the combustion device 10 is equipped with a flame temperature sensor 18, for example, this flame temperature sensor 18 is used as the output detection means. In the operation table of Fig. 2, the flame temperature that is assumed to be detected by the flame temperature sensor 18 as the combustion section temperature during combustion operation is preset as a reference temperature for each target output based on combustion experiments. Note that the boiler body temperature sensor 15a may also be used as the output detection means, and the operation table presets the reference temperature that is assumed to be detected by the boiler body temperature sensor 15a for each target output.

[0028] During combustion operation based on the operation table, if the flame temperature of the combustion unit rises by more than a certain temperature above the reference temperature due to an increase in combustion output, the control unit 6 determines that the remaining amount of LP gas is low and issues a notification of the decrease in the remaining amount. For example, if the target output is the maximum heat output of the combustion device 10 and the control unit 6 detects a rise of more than 30°C above the set reference flame temperature A [°C] of the combustion unit, the control unit 6 determines that the combustion output has risen by more than a certain temperature above the reference value due to the decrease in the remaining amount of LP gas. The control unit 6 then notifies the operation terminal 6a of the decrease in the remaining amount of the gas cylinder, for example, by displaying or outputting audio. The certain temperature corresponds to the temperature rise when the combustion output rises by the reference value, and is set in advance, for example, by experimentation, for each target output.

[0029] Furthermore, the control unit 6 starts combustion operation based on the operation table and controls the combustion operation by adjusting the opening of the gas proportional valve 16 and the rotation speed of the combustion fan 13 according to, for example, the flame temperature of the combustion unit or the temperature detected by the first outlet hot water temperature sensor 5b, so as to match the combustion output with the target output. The control unit 6 can also use this combustion fan 13 as an output detection means. For example, when the remaining amount of LP gas in the gas cylinder becomes low and the combustion output increases, the control unit 6 controls the combustion operation by reducing the rotation speed of the combustion fan 13 to reduce the combustion output.

[0030] When the rotation speed of the combustion fan 13 is reduced by a certain number of rotations or more from the reference rotation speed set in the operation table, the control unit 6 determines that the combustion output has increased by a certain number of rotations or more from the reference value due to a decrease in the remaining amount of LP gas, and notifies the operation terminal 6a of the decrease in the remaining amount of gas in the gas cylinder. The reduction correction by a certain number of rotations corresponds to the rotation speed of the combustion fan 13 that is reduced when adjusting the combustion output that has increased by the reference value to the target output, and is set in advance for each target output based on combustion experiments, for example. The reduction rate of the rotation speed may also be used as the criterion for judgment.

[0031] Furthermore, the control unit 6 starts combustion operation based on the operation table and controls the combustion operation to match the combustion output to the target output by adjusting the aperture of the gas proportional valve 16 and the rotation speed of the combustion fan 13, for example, in accordance with the flame temperature of the combustion unit or the temperature detected by the first outlet hot water temperature sensor 5b. The control unit 6 can also use this gas proportional valve 16 as an output detection means. For example, when the remaining amount of LP gas in the gas cylinder decreases and the combustion output increases, the control unit 6 controls the combustion operation to reduce the aperture of the gas proportional valve 16 and thereby lower the combustion output.

[0032] When the opening of the gas proportional valve 16 is reduced by a certain amount or more from the reference opening set in the operation table, the control unit 6 determines that the combustion output has increased by a certain amount or more from the reference value due to a decrease in the remaining amount of LP gas, and notifies the operation terminal 6a of the decrease in the remaining amount of gas cylinder. The reduction correction by a certain amount of opening corresponds to the opening of the gas proportional valve 16 that is reduced when adjusting the combustion output that has increased by the reference value to the target output. For example, when the opening is specified by the number of steps, the certain opening is preset for each target output based on combustion experiments according to the number of steps. The reduction rate of the opening may also be used as the criterion for judgment.

[0033] Water heater 1 uses the heat of combustion from combustion device 10 to heat clean water in heat exchange section 3, and supplies the heated water to the outside by mixing the clean water with the clean water and adjusting the temperature. Control section 6 adjusts the combustion output of combustion device 10 and the mixing ratio at which clean water is mixed to adjust the temperature of the hot water, according to the target output of combustion device 10 for supplying hot water at the target hot water temperature to the outside.

[0034] The control unit 6 starts the combustion operation based on the operation table for the combustion operation and controls the combustion operation so as to reduce the difference between the target output and the combustion output calculated by the control unit 6 based on the feedwater flow rate, feedwater temperature, and hot water temperature heated by the heat exchange unit 3. The control unit 6 can also use the feedwater flow rate sensor 4c, feedwater temperature sensor 4b, and first hot water outlet temperature sensor 5b, which detect the feedwater flow rate, feedwater temperature, and hot water temperature heated by the heat exchange unit 3, as output detection means. For example, since the calculated combustion output increases when the remaining amount of LP gas in the gas cylinder decreases, the control unit 6 determines that the remaining amount of LP gas has decreased if the combustion output increases by more than a reference value relative to the target output, and issues a notification of the decrease in the remaining amount.

[0035] The operation and effects of the combustion device 10 will now be described. When combustion operation is performed based on the operation table, the control unit 6 of the combustion device 10 notifies the user that the remaining amount of LP gas in the gas cylinder is decreasing if the combustion output detected by the output detection means (flame temperature sensor 18, combustion fan 13, gas proportional valve 16) rises by more than a reference value. As the remaining amount of LP gas in the gas cylinder decreases and the time for replacement approaches, the proportion of butane, which has a high calorific value, increases relative to the main component propane. Therefore, the combustion output increases compared to combustion operation based on the operation table. Therefore, the control unit 6 can detect that the remaining amount of LP gas is decreasing by detecting the combustion output using the output detection means, and can notify the user that the time for gas cylinder replacement has arrived by notifying the user that the LP gas remaining amount is low, thereby encouraging the user to replace the gas cylinder.

[0036] The control unit 6 performs combustion operation based on the operation table, and determines that the combustion output has increased by more than a reference value when the temperature of the combustion unit is higher than the reference temperature set in the operation table of the flame temperature sensor 18 by a certain amount. Therefore, the control unit 6 can notify the user of a decrease in the remaining amount of LP gas, which causes the combustion output to increase by more than the reference value, and can prompt the user to replace the gas cylinder.

[0037] The control unit 6 performs combustion operation based on the operation table, and when adjusting the combustion output to the target output, if the rotation speed of the combustion fan 13 is reduced by more than a certain amount from the reference rotation speed set in the operation table in order to reduce the combustion output, the control unit 6 determines that the combustion output has increased by more than the reference value. Therefore, the control unit 6 can notify the user of a decrease in the remaining amount of LP gas, which causes the combustion output to increase by more than the reference value, and can prompt the user to replace the gas cylinder.

[0038] When the control unit 6 performs combustion operation based on the operation table and adjusts the combustion output to the target output, if the opening of the gas proportional valve 16 is reduced by more than a certain amount from the reference opening set in the operation table in order to reduce the combustion output, the control unit 6 determines that the combustion output has increased by more than a reference value. Therefore, the control unit 6 can notify the user of a decrease in the remaining amount of LP gas, which causes the combustion output to increase by more than the reference value, and can prompt the user to replace the gas cylinder.

[0039] The combustion device 10 may be mounted on a heating device such as a gas fan heater. In addition, a person skilled in the art can implement the present invention in various forms by adding various modifications to the above embodiment without departing from the spirit of the present invention, and the present invention includes such modifications. [Explanation of symbols]

[0040] 1: Hot water supply equipment 3:Heat exchange section 4: Water supply section 4a: Water supply passage 4b: Water supply temperature sensor 4c: Water supply flow sensor 5: Tap area 5a: Hot water passage 5b: First hot water outlet temperature sensor 5c: Second hot water outlet temperature sensor 6: Control unit (control means) 6a: Operation terminal 7a: Bypass passage 7b: Bypass flow control valve 10: Combustion equipment 11a to 11d: Combustion stage (combustion section) 12: Gas supply unit 12a: Gas passage 12b: Gas passage opening / closing valve 13: Combustion fan (output detection means) 14: Exhaust port 15: Can body case 15a: Can body temperature sensor 16: Gas proportional valve (output detection means) 17a to 17d: Combustion stage on-off valves 18: Flame temperature sensor (output detection means)

Claims

1. In a combustion device that burns LP gas filled in a gas cylinder as fuel in a combustion section, The system has a control means for controlling combustion operation so that the combustion output becomes a target output based on a preset operation table, and a combustion fan for supplying combustion air to the combustion section as an output detection means for detecting the combustion output, The control means, when controlling the combustion operation based on the operation table and adjusting it to achieve the target output, determines that the combustion output has increased by more than a reference value relative to the target output if the rotation speed of the combustion fan is reduced by more than a certain amount from the reference rotation speed, and in this case, issues an alert that the remaining amount of LP gas in the gas cylinder is low.

2. A combustion device that burns LP gas filled in a gas cylinder as fuel in a combustion section, The system has a control means for controlling combustion operation so that the combustion output becomes a target output based on a preset operation table, and a gas proportional valve for adjusting the supply flow rate of LP gas as an output detection means for detecting the combustion output, The control means, when controlling the combustion operation based on the operation table and adjusting it to achieve the target output, determines that the combustion output has increased by more than a reference value relative to the target output if the opening of the gas proportional valve is reduced by more than a certain amount from the reference opening, and in this case, issues an alert that the amount of LP gas remaining in the gas cylinder is low.

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