JP2009162130A - Fuel supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel supply device capable of optimizing a mixing ratio of air and/or oxygen according to a heating value possessed by fuel gas, and controlling a flow rate of the fuel gas taking the heating value as a control value. <P>SOLUTION: A first flow rate adjusting device for controlling a flow rate of fuel gas controls a heat quantity flow rate of the fuel gas and acquires a heating value ratio with respect to the heating value of fuel gas in a standard state from a heating value of the fuel gas. According to the heating value ratio, a flow rate of air and/or oxygen which is an optimum mixing ratio [A/F], [O<SB>2</SB>/F] of air and/or oxygen mixed into the fuel gas is acquired to be set as a control target value of a second flow rate adjusting device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides a fuel supply capable of optimizing the mixing ratio of air and / or oxygen in accordance with the calorific value of the fuel gas when the fuel gas is mixed with air and / or oxygen and supplied to the fuel gas combustion system. Relates to the device.

  When fuel gas is burned using a burner, the fuel gas supply amount (fuel gas flow rate) and air supply amount (air flow rate) supplied to the burner are adjusted to optimize the combustion state, respectively. The ratio of the air mass to the fuel gas mass in the air-fuel mixture, that is, the so-called air-fuel ratio [A / F] is made constant. In such air-fuel ratio control, for example, the mass flow rate of the fuel gas and the mass flow rate of air are measured using a thermal mass flow sensor, for example, and at least one of the flow rates of the fuel gas and air ( (Mass flow rate) is adjusted (controlled) (see, for example, Patent Document 1).

Further, when performing the above-described air-fuel ratio control, if there are a plurality of types having different compositions as the fuel gas or the composition ratio changes, the amount of combustion heat and the amount of heat generated per unit time are obtained. Is also proposed to be fed back to the flow rate control (see, for example, Patent Document 2). Even when air and oxygen are mixed in the fuel gas and the mixture is supplied to the burner and burned, the mass flow rates of the fuel gas, air and oxygen are measured, and each of these components is measured. It has also been proposed to control each flow rate so as to achieve an ideal mixing ratio (see, for example, Patent Document 3).
JP 2002-267159 A JP 2003-35612 A JP 2007-87029 A

  By the way, in a burner used in a glass tube sealing process or the like, it is required to control the combustion amount with high accuracy. However, as described above, the supply amount is controlled based on the mass flow rate of the fuel gas, and each flow rate of air and oxygen is controlled so that each component of the fuel gas, air and oxygen has an ideal mixing ratio. However, when the composition of the fuel gas changes, there is a problem that the combustion amount (heat generation amount) of the fuel gas (air mixture) cannot be maintained at a desired control value. Moreover, since the gas density also changes with the change in the composition of the fuel gas, there arises a problem that the mixing ratio also deviates from the ideal state. These problems also cause incomplete combustion of fuel gas.

  The present invention has been made in consideration of such circumstances, and its purpose is to control the flow rate of the fuel gas using the heating value as a control value regardless of the difference or change in the composition of the fuel gas. An object of the present invention is to provide a fuel supply device capable of optimizing the mixing ratio of air and / or oxygen in accordance with the amount of heat generated.

In order to achieve the above-described object, a fuel supply device according to the present invention includes a first flow rate adjustment device having a flow rate adjustment valve that adjusts the flow rate of fuel gas, and a flow rate adjustment valve that adjusts the flow rate of air and / or oxygen. A device comprising a second flow rate adjusting device in parallel, and supplying the fuel gas with air and / or oxygen to the fuel gas combustion system,
The first flow rate adjusting device includes:
<a1> a calorific flow rate calculating means for obtaining a calorific flow rate of the fuel gas from an output of a thermal mass flow sensor provided in the flow path of the fuel gas;
<a2> The flow rate adjusting valve is controlled according to the heat flow rate set as the control target value and the heat flow rate per unit volume of the fuel gas determined by the heat flow rate calculation means to control the flow rate of the fuel gas. First flow rate adjusting means for adjusting;
<a3> a calorific value detection means for obtaining a calorific value per unit volume of the fuel gas;
<a4> The calorific value ratio of the fuel gas based on the calorific value per unit volume in the reference state of the fuel gas obtained in advance and the calorific value per unit volume of the fuel gas obtained by the calorific value detection means Calorific value ratio calculating means for obtaining
<a5> Optimum mixing ratio [A / F] of air and fuel gas and / or air for optimal combustion of the fuel gas in accordance with the calorific value ratio obtained by the calorific value ratio calculating means And a mixing ratio setting means for obtaining an optimal mixing ratio [O ₂ / F] of the fuel gas;
<a6> From the flow rate of the fuel gas adjusted by the first flow rate adjusting means and the mixing ratios [A / F] and [O ₂ / F] obtained by the optimum ratio setting means, air and / or A flow rate setting means for obtaining a flow rate setting value for oxygen and notifying the second flow rate adjustment device;
The second flow rate adjusting device includes:
<b> A second flow rate adjusting means for adjusting the flow rate of the air and / or oxygen by controlling the flow rate adjusting valve in accordance with a flow rate setting value notified from the first flow rate adjusting means. Yes.

  Incidentally, the fuel gas is a CH-based gas, and the calorific flow rate calculation means refers to the thermal formula with reference to, for example, a table describing the relationship between the output of the thermal mass flow sensor and the calorific flow rate of the fuel gas. The heat flow rate of the fuel gas is determined according to the output of the mass flow sensor. The calorific value detection means obtains the calorific value per unit volume of the fuel gas from the output of the thermal mass flow sensor when the flow of the fuel gas is stopped, or the thermal mass flow sensor The calorific value per unit volume of the fuel gas is determined from the change in the output of the thermal mass flow sensor when the driving conditions are changed. In addition, you may make it obtain | require the emitted-heat amount per unit volume of the said fuel gas from the output of the calorie | heat amount sensor attached to the said thermal mass flow sensor.

  According to the fuel supply apparatus having the above configuration, the heat flow rate of the fuel gas is obtained from the output of the thermal mass flow sensor that detects the mass flow rate of the fuel gas in the heat flow rate calculation means, and is set as the control target value in the flow rate control means. Since the operation of the flow rate adjustment valve is controlled by comparing the heat quantity flow rate obtained with the heat quantity flow rate obtained by the heat quantity flow rate calculation means, the flow rate of the fuel gas is made constant at the heat quantity flow rate set as the control target value. Can do. That is, the flow rate of the fuel gas can be controlled using the heat flow rate determined by the mass flow rate of the fuel gas and the calorific value per unit volume of the fuel gas as a management value.

Further, a ratio of a calorific value per unit volume of the fuel gas to a calorific value per unit volume in the reference state of the fuel gas obtained in advance, that is, a calorific value ratio is obtained, and air and / or oxygen is determined according to the calorific value ratio. And the flow rate of air and / or oxygen mixed with the fuel gas is set according to the mixture ratio and the flow rate of the fuel gas, so that the difference or change in the composition of the fuel gas is concerned. In addition, the mixing ratio [A / F] of air and fuel gas and / or the mixing ratio [O ₂ / F] of oxygen and fuel gas can be optimized.

  Therefore, even when the composition (type) of the fuel gas is different from the assumed composition (type) or when the composition of the fuel gas itself changes, the fuel gas is focused on the amount of heat generated by the fuel gas. The flow rate of air and / or oxygen can be optimized in accordance with the calorific value ratio, so that stable combustion of the fuel gas can be realized simply and effectively. . In addition, since the relationship between the output of the thermal mass flow sensor and the heat flow rate of the fuel gas is obtained in advance and described as a table, the heat flow rate of the fuel gas can be easily obtained according to the sensor output. The effect that the burden of flow control does not increase so much is exhibited.

Hereinafter, a fuel supply apparatus according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a fuel supply device according to this embodiment. 10 is a flow rate control device [first flow rate adjusting means] for controlling the supply amount of fuel gas (F), and 20 is supply of air (A) A flow rate control device [second flow rate adjusting means] for controlling the amount, and 30 is a flow rate control device [second flow rate adjusting means] for controlling the supply amount of oxygen (O ₂ ). These flow rate supply devices 10, 20, 30 are provided in parallel, and the fuel gas, air, and oxygen supplied through the respective flow rate supply devices 10, 20, 30 are controlled by the mixer 41, Then, the mixture is sequentially mixed through the burner 43 and supplied to the burner 43 as a combustor. Incidentally, the flow rate supply device 10 plays a role of controlling the supply amount of the fuel gas in accordance with the required combustion amount (heat generation amount) in the burner 43, and each of the flow rate supply devices 20 and 30 It plays a role of controlling each supply amount (flow rate) of air and oxygen for completely burning the fuel gas according to the supply amount (flow rate) of the gas.

  Each of the flow control devices 10, 20, and 30 is basically provided in the fuel gas (air, oxygen) flow path 1 as shown in FIG. 1 and FIG. A thermal mass flow sensor 3 that includes a flow rate adjusting valve (valve) 2 that adjusts the flow rate of gas (air, oxygen) and detects the mass flow rate of fuel gas (air, oxygen) that flows through the flow path 1. Is provided. The valve opening degree of the flow rate adjusting valve 2 is controlled by a valve control circuit 4 that is driven according to the flow rate detected by the thermal mass flow rate sensor 3. In particular, the flow rate adjusting valve (valve) 2 operates under the control of the control calculator 5, the flow rate detected using the thermal mass flow sensor 3, and the control target value set in the control calculator 5. The flow rate of the fuel gas (air, oxygen) is adjusted by feedback control so that there is no deviation from (flow rate).

  Incidentally, the flow rate control devices 10, 20, and 30 configured by including the flow rate adjusting valve 2 and the thermal mass flow rate sensor 3 described above are fuel gas (air, oxygen) as schematically shown in FIG. A flow rate adjusting valve (valve) 2 in which a thermal mass flow sensor 3 is provided on a flow path body 11 in which the flow path 1 is formed so as to face the flow path 1 and the valve opening degree is controlled by a solenoid mechanism 12. Is incorporated into the flow path body 11 so as to partition between the inlet and the outlet of the flow path 1. Further, in this flow control device, the drive unit 13 on which the control arithmetic unit 5 and the valve control circuit 4 described above are mounted is integrally assembled on the outside of the flow path body 11. The flow control device and the thermal mass flow sensor 3 having the above-described configuration are well known as introduced in the above-mentioned Patent Document 3 and the like.

In the present invention, the output of the thermal mass flow sensor 3 for detecting the mass flow rate of the fuel gas (air, oxygen) in the flow rate control devices 10, 20, 30 basically configured as described above is We focus on the fact that it is proportional to the heat flow rate of the fuel gas (air, oxygen). That is, the thermal mass flow sensor 3 used for detecting the mass flow rate Fm of the fuel gas (air, oxygen) detects the temperature distribution of the fluid (fuel gas, air, oxygen) in the vicinity of the sensor. The distribution varies depending on the thermal diffusivity α of the fuel gas (air, oxygen) and the flow velocity (volume flow rate) of the fuel gas (air, oxygen). Incidentally, the thermal diffusivity α of the fuel gas (air, oxygen) is λ, the thermal conductivity of the fuel gas (air, oxygen), ρ, the density of the fuel gas (air, oxygen), and the fuel gas (air, oxygen). Α = λ / (ρ × Cp) where Cp is the specific heat of
As given.

  On the other hand, the calorific value Qv per unit volume of the fuel gas varies depending on its composition (type). For example, the calorific value Qv per unit volume at a reference temperature (for example, 0 ° C.) of a CH gas that is a general fuel gas is As shown in the table.

  The difference in the calorific value Qv per unit volume of the fuel gas is mainly caused by the difference in the gas density ρ accompanying the difference in the composition of the fuel gas. Therefore, when the composition of the fuel gas whose mass flow rate Fm is detected using the thermal mass flow sensor 3 changes, the gas density ρ of the fuel gas changes accordingly, and further along with the change of the gas density ρ. Thus, the mass flow rate Fm detected by the thermal mass flow sensor 3 changes.

  However, the density ρ of the fuel gas containing the above-described CH-based gas is proportional to the reciprocal [1 / α] of the thermal diffusivity α as shown in FIG. 4 regardless of the difference in the composition. Further, the calorific value Qv per unit volume of the fuel gas composed of the CH-based gas is proportional to the density ρ regardless of the composition as shown in FIG. The thermal mass flow sensor 3 used for detecting the mass flow rate Vm of the fuel gas obtains an output corresponding to the temperature distribution of the fuel gas in the vicinity of the sensor, and the temperature distribution is the flow rate Fv of the fluid (fuel gas). It varies depending on the calorific value Qv per unit volume. In other words, the signal (sensor output) output from the thermal mass flow sensor 3 is proportional to the calorific value Qv per unit volume regardless of the composition of the CH-based fuel gas, and at the same time the flow velocity (volume flow rate) Fv. It is proportional to Therefore, the signal (sensor output) output from the thermal mass flow sensor 3 is relatively defined as the product of the calorific value Q per unit volume of the fuel gas and its flow velocity (volume flow rate) Fv as shown in FIG. It can be said that it has a one-to-one relationship with the heat quantity flow rate Fc.

  Therefore, in the first flow rate control device 10 in the fuel supply device according to the present invention, the volume flow rate Fv of the fuel gas and the unit volume of the fuel gas from the output (sensor output) of the thermal mass flow rate sensor 3 are determined. There is provided a calorific flow rate detecting unit (caloric flow rate calculating means) 6 for obtaining a calorific flow rate Fc of the fuel gas determined by the calorific value Qv. That is, instead of obtaining the mass flow rate Fm of the fuel gas from the output (sensor output) of the thermal mass flow sensor 3, the heat quantity flow rate Fc of the fuel gas is obtained.

  Then, as the control target value to be given to the control calculator 5, the heat quantity flow Fo for directly managing the heat quantity given to the combustion system such as the burner is set, and this management set value (heat quantity flow Fo) and the heat quantity flow rate are set. The operation of the flow rate adjusting valve 2 described above is controlled so that the heat flow rate Fc of the fuel gas becomes the set flow rate Fo by comparing with the heat flow rate Fc obtained by the detection unit (heat flow rate calculation means) 6. It is characterized by that. In this case, the control calculator 5 functions as a fuel gas flow rate control means based on the heat flow rate Fc detected using the thermal mass flow rate sensor 3.

  According to the first flow control device 10 configured as described above, the heat flow rate Fc of the fuel gas is directly detected from the output (sensor output) of the thermal mass flow sensor 3, and the detected heat flow rate Fc is detected. And the heat flow rate Fo set as the control target value, the operation of the flow rate adjustment valve 2 is controlled to adjust the flow rate (heat flow rate; calorific value) F of the fuel gas. Even if it changes, the calorific value flow rate (heat generation amount) Fc of the fuel gas supplied to the combustion system such as the burner through the flow rate control device (flow rate adjusting valve 2) can be kept constant and stable.

  In particular, the flow rate control is performed by paying attention to the calorific value Qv of the fuel gas, unlike the flow rate control of the fuel gas based on the mass flow rate Fm detected using the conventional general thermal mass flow sensor 3. The heat flow rate (heat generation amount) Fc can be made constant by reliably following not only the flow rate variation but also the heat generation amount variation caused by the composition change. Therefore, it is not necessary to determine whether the change in the output of the thermal mass flow sensor 3 is caused by the change in the flow rate or the change in the amount of heat accompanying the change in the composition, and the calorific value Qv possessed by the fuel gas. As a result, it is possible to achieve a practically great effect such as the ability to stably perform the flow control focusing on the above.

Incidentally, in order to stably and completely burn the above-described fuel gas, it is necessary to mix air and oxygen in the fuel gas at an appropriate ratio (ratio) as described above. Incidentally, the ideal mixture ratio of air and fuel gas in the air-fuel mixture when burning CH gas completely (ideal air-fuel ratio; A / F), and the ideal mixture ratio of oxygen and fuel gas, so-called ideal acid The fuel ratio [O ₂ / F] is as shown in the following table.

That is, when the composition of the combustion gas changes, the ideal air fuel ratio [A / F] and the ideal acid fuel ratio [O ₂ / F] also change accordingly. Therefore, in the fuel supply device according to the present invention, the flow rate control device 10 controls the flow rate control of the fuel gas in accordance with the heat generation flow rate as shown in FIG. The calorific value per unit volume of the fuel gas flowing through the flow rate control device 10 is obtained, the calorific value per unit volume in the reference state of the fuel gas of the type assumed in advance, and the unit volume of the fuel gas obtained as described above. The change in the amount of generated heat is evaluated by obtaining the ratio of the amount of generated heat per unit (the amount of generated heat). Then, an optimal mixing ratio [A / F] of air to be mixed with the fuel gas and an optimal mixing ratio [O ₂ / F] of oxygen to be mixed with the fuel gas are determined according to the calorific value ratio. The flow rates of air and oxygen mixed in the fuel gas are set according to the mixing ratio [A / F], [O ₂ / F] and the flow rate of the fuel gas. The set flow rates of air and oxygen thus set are notified to the second flow rate control devices 20 and 30, respectively, and the second flow rate control devices 20 and 30 respectively control the air and oxygen flow rates according to the notified set flow rates. Control the flow rate. Through such flow rate control, the flow rates of fuel gas, air, and oxygen are optimized according to the amount of combustion heat generated by the burner 43, and an air-fuel mixture adjusted to an ideal mixing ratio is supplied to the burner 43. The

  That is, in the fuel supply apparatus according to the present invention, in addition to the above-described configuration of the first flow rate control device 10, a calorific value detection means 7 for obtaining a calorific value per unit volume of the fuel gas as shown in FIG. And the calorific value per unit volume in the reference state of the CH-based fuel gas obtained in advance and the calorific value per unit volume of the fuel gas obtained by the calorific value detection means 7, A calorific value ratio calculating means 8 for obtaining a calorific value ratio of the fuel gas is provided.

  Further, the first flow rate control device 10 has an ideal mixing ratio [ideal air-fuel ratio; A / F] of air and fuel gas necessary for complete combustion of the CH-based fuel gas to the calorific value of the fuel gas. A table 11 registered in advance according to the ratio is provided. In the first flow rate control device 10, the air-fuel ratio [A / F] between the air to be mixed with the fuel gas and the fuel gas with reference to the table 11 according to the calorific value ratio obtained as described above. The air flow rate setting unit 12 obtains the supply amount of air to be mixed with the fuel gas as the control target value according to the air-fuel ratio [A / F] and the flow rate of the fuel gas.

Similarly, in the first flow rate control device 10, an ideal mixing ratio of oxygen and fuel gas necessary for complete combustion of the CH-based fuel gas, so-called ideal acid fuel ratio [O ₂ / F], is obtained. A table 13 registered in advance in accordance with the calorific value ratio of the fuel gas is provided. In the first flow rate control device 10, referring to the table 13 in accordance with the calorific value ratio obtained as described above, the oxygen to be mixed with the fuel gas and the mixing ratio of the fuel gas, that is, the above-described acid fuel ratio [ A / F] is obtained, and the oxygen flow rate setting unit 14 sets the supply amount of oxygen to be mixed with the fuel gas in accordance with the acid ratio [O ₂ / F] and the flow rate of the fuel gas as a control target value. Looking for.

  The supply amounts (control target values) of air and oxygen thus determined are notified to the second flow rate control devices 20 and 30, respectively, and the flow rate control targets in these flow rate control devices 20 and 30, respectively. Set as a value. The flow control devices 20 and 30 respectively control the flow rates of air and oxygen under the set control target values, thereby optimizing the supply amount of the air and oxygen according to the heat generation flow rate of the fuel gas. We are trying to make it. As a result, the mixing ratio of the fuel gas, air, and oxygen through the mixers 41 and 42 is optimized according to the calorific value of the fuel gas, and the mixture is supplied to the burner 43.

  The calorific value detection means 7 in the first flow rate control device 10 described above generates, for example, the calorific value per unit volume of the fuel gas from the output of the thermal mass flow sensor 3 when the flow of the fuel gas is stopped. It is configured to determine Qv. Specifically, when the flow rate adjusting valve (valve) 2 is closed and the flow of the fuel gas is stopped, the mass (gas density) of the fuel gas is obtained from the output of the thermal mass flow sensor 3, and this gas The heat generation amount is detected using the fact that the density is proportional to the heat generation amount Qv per unit volume of the fuel gas.

  Instead of such a calorific value detection method, for example, a so-called gas reservoir portion in which the fuel gas only enters a part of the fuel gas passage 1, that is, no flow of the fuel gas occurs, is recessed. The thermal mass flow sensor 3a independent from the thermal mass flow sensor 3 is provided in the gas reservoir, and the output of the thermal mass flow sensor 3a is performed in parallel with the detection of the thermal flow rate Fc described above. Of course, the calorific value Qv per unit volume of the fuel gas can be obtained. In this way, the calorific value Qv per unit volume of the fuel gas can be obtained while the fuel gas is continuously flowing without closing the flow rate adjusting valve (valve) 2 and stopping the flow of the fuel gas. It can be obtained.

  Alternatively, for example, as disclosed in JP-T-2004-514138, the heater power when the heater temperature, which is the driving condition of the thermal mass flow sensor 3, is changed in two stages, is obtained, and from these heater powers, respectively. The calorific value detecting means 7 can be configured to obtain the calorific value Qv per unit volume from the obtained thermal conductivity λ of the fuel gas according to the relationship between the thermal conductivity λ and the density of the fuel gas. .

  In addition, the calorific value ratio calculation means 8 has a calorific value Qv per unit volume of the fuel gas obtained by the calorific value detection means 7 as described above, and a reference state obtained in advance for the assumed type of fuel gas. The ratio of the calorific value per unit volume to Qs, that is, the calorific value ratio [Qv / Qs] is obtained. The calorific value Qs per unit volume in the reference state of the fuel gas is, for example, the calorific value Qs per unit volume obtained in advance for each fuel gas type by designating the type of fuel gas to be controlled. It is obtained by referring to a table in which is described.

In this way, the calorific value ratio [Qv / Qs] of the fuel gas is obtained by the calorific value ratio calculation means 7 to determine how much the calorific value Qv of the fuel gas is from the calorific value Qs of the fuel gas assumed in advance. It becomes possible to grasp whether it is changing. Incidentally, the cause of the change in the calorific value Qv of the fuel gas is exclusively the change in the composition of the fuel gas. As the composition changes, the optimum ideal air / fuel ratio [A / F] and ideal acid / fuel ratio [O ₂ / F] for burning the fuel gas also change. Accordingly, as described above, the flow rate setting that regulates the supply amounts (flow rates) of air and oxygen to be mixed with the fuel gas according to the calorific value ratio [Qv / Qs] of the fuel gas and the heat flow rate Fc of the fuel gas. If the value is obtained and the operation of the second flow control devices 20 and 30 is controlled, the air-fuel ratio [A / F] and the acid-fuel ratio [O ₂ / F] for forming the air-fuel mixture are optimized. Can be realized. Conceptually, for example, when the calorific value ratio of the CH-based fuel gas is obtained as [1.1], it is determined that the calorific value is increased by 10% with the change in the composition of the fuel gas, The supply amount of air and oxygen necessary for the combustion of the fuel gas may be increased by 10%.

  Thus, according to the fuel supply apparatus configured as described above, the supply amount of the fuel gas is controlled on the basis of the heat generation flow rate based on the heat generation amount of the fuel gas. Regardless of the calorific value per unit volume of the gas, the supply calorific value of the fuel gas can be accurately controlled. Moreover, even if the composition of the fuel gas is different from the composition assumed in advance and the calorific value per unit volume of the fuel gas is different from the calorific value per unit volume of the assumed type of fuel gas, it is obtained as described above. Since the flow rates of air and oxygen are corrected according to the calorific value ratio, air and oxygen can be mixed with the fuel gas at an optimum ratio according to the composition (heat value) of the fuel gas. Therefore, it is possible to completely burn the combustion gas in a state in which the mixing ratio of air and oxygen is optimized, and the effects of being able to stably optimize the combustion temperature, the state of the flame, and the like are exhibited.

  Moreover, since the first flow control device 10 can manage the operating conditions of the second flow control devices 20 and 30 according to the calorific value of the fuel gas, the system configuration can be greatly simplified. Can be achieved. Further, as the second flow rate control devices 20 and 30, there is an effect that it is possible to use a general-purpose flow rate control device (mass flow controller) which is generally used conventionally as it is.

  The present invention is not limited to the embodiment described above. For example, the mass flow rate detected by the thermal mass flow sensor 3 can be output in parallel with the heat flow rate obtained by the heat flow rate detection unit 6. It is also possible to adopt a configuration in which flow rate control based on the heat flow rate and flow rate control based on the mass flow rate can be set selectively. As for the flow rate control for air and oxygen, the mass flow rate control may be performed assuming that the components are constant. Needless to say, the present invention is also applicable to a fuel supply apparatus that mixes only one of air and oxygen with fuel gas. Furthermore, it is of course possible to incorporate functions such as known temperature correction means as appropriate, and the present invention can be implemented with various modifications without departing from the gist thereof.

1 is a schematic configuration diagram of a fuel supply device according to an embodiment of the present invention. FIG. 2 is a schematic functional configuration diagram of a flow control device used in the fuel supply device shown in FIG. 1. The figure which shows the example of the flow-path structure of the flow control apparatus shown in FIG. The figure which shows the relationship between the density of CH type fuel gas, and the reciprocal [1 / (alpha)] of thermal diffusivity (alpha). The figure which shows the relationship between the density of CH type fuel gas, and the emitted-heat amount per unit volume. The figure which shows the relationship between the calorie | heat amount flow rate of fuel gas, and the sensor output of a thermal mass flow sensor.

Explanation of symbols

1 Fuel gas flow path 2 Flow control valve (valve)
3 Thermal mass flow sensor 4 Valve control circuit 5 Control calculator 6 Heat quantity flow detector (heat quantity flow calculation means)
7 Heat generation amount detection means 8 Heat generation amount ratio calculation means 10, 20, 30 Flow rate control device 11 A / F table 12 Air flow rate setting unit 13 O ₂ / F table 14 Oxygen flow rate setting unit

Claims (3)

A fuel supply device that mixes air and / or oxygen with fuel gas and supplies the fuel gas to a combustion system of the fuel gas, the first flow rate adjustment device having a flow rate adjustment valve for adjusting the flow rate of the fuel gas, A second flow control device having a flow control valve for adjusting the flow rate of air and / or oxygen,
The first flow rate adjusting device includes a calorific flow rate calculating means for obtaining a calorific flow rate of the fuel gas from an output of a thermal mass flow sensor provided in the fuel gas passage,
The flow rate adjustment valve is controlled to adjust the flow rate of the fuel gas according to the heat flow rate set as the control target value and the heat flow rate per unit volume of the fuel gas obtained by the heat flow rate calculation means. 1 flow rate adjusting means;
A calorific value detection means for obtaining a calorific value per unit volume of the fuel gas;
From the calorific value per unit volume in the reference state of the fuel gas obtained in advance and the calorific value per unit volume of the fuel gas obtained by the calorific value detection means, the calorific value ratio of the fuel gas is calculated. Calorific value ratio calculating means to be obtained;
The optimum mixing ratio [A / F] of the air and the fuel gas and / or air and the fuel gas for optimally burning the fuel gas in accordance with the calorific value ratio obtained by the calorific value ratio calculating means A mixing ratio setting means for obtaining an optimal mixing ratio [O ₂ / F] with:
The flow rate for air and / or oxygen from the flow rate of the fuel gas controlled by the first flow rate adjusting means and the mixing ratios [A / F] and [O ₂ / F] obtained by the mixing ratio setting means. Flow rate setting means for obtaining a set value and notifying the second flow rate adjustment device;
The second flow rate adjustment device includes a second flow rate adjustment unit that controls the flow rate adjustment valve according to the flow rate setting value notified from the first flow rate adjustment unit to adjust the flow rate of the air and / or oxygen. A fuel supply device comprising the fuel supply device. The fuel gas is a CH gas,
The calorific flow rate calculation means refers to a table describing the relationship between the output of the thermal mass flow sensor and the thermal flow rate of the fuel gas, and the calorific flow rate of the fuel gas according to the output of the thermal mass flow sensor The fuel supply device according to claim 1, wherein   The calorific value detection means is configured to output the thermal mass flow sensor from the output of the thermal mass flow sensor in a state where the flow of the fuel gas is stopped or when the driving condition of the thermal mass flow sensor is changed. 2. The fuel supply device according to claim 1, wherein a heat generation amount per unit volume of the fuel gas is obtained from an output change or an output of a calorific sensor provided in the thermal mass flow sensor.

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