Flow rate control system and combustion control system equipped with same

Abstract

To safely save manpower through automation of various types of adjustment, such as a flow rate of fuel gas, while improving economic efficiency by maintaining a simple configuration without providing a flow meter.SOLUTION: By operating a blower B, combustion gas A is caused to flow in on-site fuel piping H1 via on-site connection piping H3. While a fuel flow control valve RVg is maintained at a predetermined initial set opening and pressure at a primary side inlet is maintained at predetermined fuel flow rate control pressure by using the blower B, pressure at a secondary side outlet is set to be predetermined initial set secondary pressure by using a secondary side fuel pressure adjustment mechanism GV. Then, while fuel piping on-off valves SV1, SV2 are opened and a connection piping on-off valve SV3 is closed, the opening of the fuel flow control valve RVg is controlled on the basis of opening fuel flow rate relation stored in a storage section S3 to control a flow rate of fuel gas G to a target flow rate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a flow rate control system for controlling the flow rate of a controlled gas including a fuel gas, and a combustion control system including the same. [Background technology]

[0002] Conventionally, a pressure equalizing valve type combustion control system used in industrial furnaces and the like has been known (see Patent Document 1). The pressure equalizing valve type combustion control system is configured to include, for example, a fuel pipe connected to a burner and passing fuel gas such as city gas 13A, an air pipe similarly connected to the burner and passing combustion air, a temperature regulator that controls the output of the burner based on the temperature of the industrial furnace, a control valve connected by a linkage to a control motor that controls the flow rate of air passing through the air pipe based on a signal from the temperature regulator and is controlled to open and close, a pressure equalizing valve that controls the opening degree of the fuel pipe in a form corresponding to the air pressure on the secondary side of the control valve of the air pipe, and a blower that pressure-feeds combustion air to the air pipe. In this pressure equalizing valve type combustion control system, the linkage between the control motor and the control valve is manually adjusted by an expert, and the adjustment is done at one point, so to change the air ratio, etc., manual adjustment by an expert is required again. This is the same for the double linkage type combustion control system. As another configuration, an electronic linkage type combustion control system is known, and this electronic linkage type is configured, for example, with a fuel pipe connected to the burner and through which fuel gas such as city gas 13A flows, an air pipe similarly connected to the burner and through which combustion air flows, a temperature regulator that controls the burner output based on the temperature of the industrial furnace, a control unit that receives a signal from the temperature regulator, an electronic flow meter that measures the flow rate of the fuel gas flowing through the fuel pipe and the air flow rate flowing through the air pipe and sends the results to the control unit, a fuel flow control valve that controls the flow rate of the fuel gas flowing through the fuel pipe based on the signal from the control unit, and an air flow control valve that controls the flow rate of the air flowing through the air pipe. In this electronic linkage system, the flow rate of fuel gas and combustion air are monitored by an electronic flow meter, and the air ratio based on the flow rate is also monitored. The air ratio can also be changed by changing the settings in the control unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-47654 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned pressure equalizing valve type combustion control system, for example, if the flow rate of fuel gas deviates from the target value for some reason, the user may not notice this, and the furnace temperature may not be able to be maintained at the set value. In addition, adjustments to the output and other aspects require manual adjustments by an experienced person, which makes it difficult to improve efficiency by reducing the number of people required. Furthermore, in order to adjust the flow rate of the fuel gas, etc., it is necessary to provide a relatively expensive electronic flow meter, which is problematic from the viewpoint of economy.

[0005] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a fluid flow control system that can prevent unintended combustion, etc. during adjustments, while improving economy by maintaining a simple configuration without a flow meter, and can safely achieve labor savings by automating various adjustments of the fuel gas flow rate, etc., and a combustion control system equipped with the same. [Means for solving the problem]

[0006] A flow control system for achieving the above object is a flow control system for controlling the flow rate of a control target gas including a fuel gas, and its characteristic configuration is as follows: a fuel flow control valve that is provided in an on-site fuel pipe through which the fuel gas as the gas to be controlled flows, and whose opening degree is controlled by a control command from a flow control unit; a secondary-side fuel pressure regulating mechanism that is provided at an outlet of the fuel flow control valve in the on-site fuel piping and that is capable of adjusting a pressure of the secondary-side outlet based on a measurement result of a second fuel pressure gauge that is provided at a secondary-side outlet of the fuel flow control valve; a primary-side fuel pressure regulating mechanism that is provided at a primary-side inlet of the fuel flow control valve in the on-site fuel piping and that is capable of adjusting a pressure of the primary-side inlet based on a measurement result of a first fuel pressure gauge; a fuel pipe opening / closing valve provided at a most upstream portion of a primary side of the on-site fuel pipe for opening and closing the on-site fuel pipe; a blower that is provided in an on-site combustion gas pipe through which a combustion gas as an oxidizer for the fuel gas flows and that pressure-feeds the combustion gas into the on-site combustion gas pipe; and a combustion gas pipe opening / closing valve that is located downstream of the blower and that is capable of opening and closing the on-site combustion gas pipe; a connecting pipe opening / closing valve that is provided in a field connection pipe that connects a primary side of the fuel flow control valve and a secondary side of the fuel pipe opening / closing valve of the field fuel pipe with a primary side of the combustion gas pipe opening / closing valve and a secondary side of the blower of the field combustion gas pipe, and opens and closes the field connection pipe, In a test facility including a test fuel pipe having the same diameter as the on-site fuel pipe in place of the on-site fuel pipe, a test combustion gas pipe having the same diameter as the on-site combustion gas pipe in place of the on-site combustion gas pipe, and a test connection pipe having the same diameter as the on-site connection pipe in place of the on-site connection pipe, the test facility is provided with a fuel flow meter for measuring a flow rate of a fluid flowing through the test fuel pipe, and the pressure control unit and the flow rate control unit for controlling pressure by the secondary side fuel pressure adjustment mechanism and the primary side fuel pressure adjustment mechanism are provided with the combustion gas pipe opening / closing valve and the a storage unit that stores an opening / fuel flow rate relationship between the opening of the fuel flow control valve and a flow rate measured by the fuel flow meter, after the fuel pipe opening / closing valve is closed and the connection pipe opening / closing valve is opened, the blower is operated to cause the combustion gas to flow into the test fuel pipe via the test connection pipe, the fuel flow control valve is maintained at a predetermined initial setting opening, and the pressure of the primary side inlet is maintained at a predetermined fuel flow control pressure by the primary side fuel pressure regulating mechanism, and then the pressure of the secondary side outlet is set to a predetermined initial setting secondary pressure by the secondary side fuel pressure regulating mechanism, In the on-site facility, the pressure control unit and the flow rate control unit close the combustion gas piping on-off valve and the fuel piping on-off valve and open the connecting piping on-off valve, operate the blower to flow the combustion gas into the on-site fuel piping via the on-site connecting piping, maintain the fuel flow control valve at a predetermined initial setting opening, and while the pressure of the primary side inlet is maintained at a predetermined fuel flow control pressure by the primary side fuel pressure regulating mechanism, the pressure of the secondary side outlet is set to a predetermined initial setting secondary pressure by the secondary side fuel pressure regulating mechanism, and then, based on the opening fuel flow rate relationship stored in the memory unit, control the flow rate of the fuel gas to a target flow rate by controlling the opening of the fuel flow control valve.

[0007] In the above-described characteristic configuration, using a test facility having piping of the same diameter as that of the on-site facility, the pressure on the primary side of the fuel flow control valve is configured to be maintainable at a constant pressure by the primary-side fuel pressure regulating mechanism, and the pressure on the secondary side of the fuel flow control valve is configured to be adjustable to a predetermined pressure by the secondary-side fuel pressure regulating mechanism. As a result, in both the test facility and the field facility, the secondary pressure of the fuel flow control valve can be adjusted to a constant value regardless of the secondary pressure loss in the field facility and the test facility, and the relationship between the opening degree of the fuel flow control valve and the fuel flow rate can be maintained the same in both the test facility and the field facility. As a result, the relationship between the opening of the fuel flow control valve and the flow rate of fuel passing through the test fuel pipe obtained in the test facility can be used as is in the field facility. In other words, the opening-fuel flow rate relationship obtained in the test facility can be commonly used in various field facilities having different pressure losses on the secondary side of the fuel flow control valve. Therefore, in the field facility, the flow rate of fuel flowing through the field piping can be controlled to a desired flow rate by controlling the opening of the fuel flow control valve based on the known opening-fuel flow rate relationship without providing a relatively expensive electronic flow meter. Furthermore, since the control does not require manual adjustment by an expert, it is possible to achieve efficiency by reducing the number of workers. In particular, in the above-mentioned characteristic configuration, since combustion gas is used instead of fuel gas when acquiring the opening-fuel flow rate relationship related to the fuel gas, safety can be improved compared to when fuel gas is passed through. Also, since the primary and secondary pressures of the fuel flow control valve in the field facility can be initially set using combustion gas instead of fuel gas, safety can be improved compared to when fuel gas is used. As described above, a fluid flow control system can be realized that maintains a simple configuration without a flow meter, improves economy, prevents unintended combustion during adjustments, etc., and reduces the number of personnel required by automating various adjustments such as the fuel gas flow rate.

[0008] A further characteristic configuration of the flow control system is The on-site connection pipe is provided with a first check valve that prevents the fuel gas from flowing from the on-site fuel pipe to the on-site combustion gas pipe, The test connection pipe is provided with a second check valve that prevents the fuel gas from flowing from the test fuel pipe to the test combustion gas pipe.

[0009] As described above, by providing a first check valve in the on-site connection piping and providing the second check valve in the test connection piping, it is possible to prevent fuel gas from mixing into the on-site combustion gas piping and the test combustion gas piping.

[0010] A further characteristic configuration of the flow control system is The on-site facility and the test facility are provided with an interlock mechanism that maintains the connection pipe opening / closing valve in a closed state when the fuel pipe opening / closing valve is in an open state.

[0011] According to the above characteristic configuration, in the on-site equipment, when fuel gas is flowing through the on-site fuel piping, the on-site connection piping is maintained in a closed state, thereby preventing fuel gas from mixing from the on-site fuel piping into the on-site combustion gas piping and avoiding the risk of backfire in the on-site combustion gas piping. The same effect can also be achieved in test equipment.

[0012] A further characteristic configuration of the flow control system is The flow control unit derives the opening-fuel flow rate relationship by using a corrected fuel flow rate Q' obtained by correcting the flow rate Q measured by the fuel flow meter using the conversion formula shown in the following [Formula 1], where s is the specific gravity of the fuel gas. Q'=Q / √s (Equation 1)

[0013] According to the above-described characteristic configuration, a corrected fuel flow rate Q' obtained by appropriately correcting a tentative fuel flow rate Q obtained by flowing a combustion gas using its specific gravity can be used to derive an opening-fuel flow rate relationship, which is a relationship between the corrected fuel flow rate Q' and the opening of the fuel flow control valve.

[0014] A further characteristic configuration of the flow control system is the memory unit stores a pressure-fuel-flow rate relationship between the pressure of the secondary outlet measured by the second fuel pressure gauge and the flow rate measured by the fuel flow meter after the pressure of the secondary outlet is set to a predetermined initial set secondary pressure by the secondary fuel pressure regulating mechanism in a state in which, in the test facility, the pressure control unit and the flow rate control unit close the combustion gas piping on-off valve and the fuel piping on-off valve and open the connection piping on-off valve, operate the blower to flow the combustion gas into the test fuel piping via the test connection piping, maintain the fuel flow control valve at a predetermined initial set opening, and maintain the pressure of the primary inlet at a predetermined fuel flow control pressure by the primary fuel pressure regulating mechanism, The on-site facility has an abnormality determination unit that determines that a flow control abnormality has occurred when the flow control unit controls the opening of the fuel flow control valve according to the opening-fuel-flow rate relationship to control the flow rate of the fuel gas to the target flow rate with the fuel piping on-off valve in an open state and the connecting piping on-off valve in a closed state, and when the controlled flow rate of the fuel gas differs from a flow rate derived from the pressure of the secondary side outlet measured by the second fuel pressure gauge and the pressure-fuel-flow rate relationship.

[0015] According to the above-described characteristic configuration, by monitoring whether the flow rate derived from the opening-fuel flow rate relationship is equal to the flow rate derived based on the pressure at the secondary outlet of the fuel flow control valve and the pressure-fuel flow rate relationship, it is possible to confirm whether the flow rate of fuel gas flowing through the on-site fuel piping obtained by controlling the fuel flow control valve based on the opening-fuel flow rate relationship is an appropriate flow rate. In other words, by using this principle, when the opening of the fuel flow control valve is controlled according to the opening-fuel flow rate relationship to control the fuel gas flow rate to a target flow rate, if the pressure of the secondary outlet measured by the second fuel pressure gauge and the flow rate derived from the pressure-fuel flow rate relationship differ from the target flow rate, the abnormality determination unit determines that a flow rate control abnormality has occurred, thereby making it possible to accurately determine an abnormality in the control of the fuel gas flow rate to the target flow rate.

[0016] A combustion control system for achieving the above object is a combustion control system including the flow control system described above, and also including a burner to which the fuel gas flowing through the on-site fuel piping and the combustion gas flowing through the on-site combustion gas piping are introduced, the combustion control system having the following characteristic configuration: In the on-site equipment, the flow rate control unit controls the flow rate of the fuel gas using the opening-fuel flow rate relationship that is common to different types of burners.

[0017] According to the above-mentioned characteristic configuration, even if burners having different pressure losses are used in the on-site equipment, the pressure at the secondary outlet of the fuel flow control valve can be controlled to a constant value by the secondary pressure adjustment mechanism, thereby eliminating the influence of different pressure losses of different burners, and fuel gas flow control can be performed using a common opening-fuel flow rate relationship for the different burners, making it possible to construct a simple and economical system that does not require the installation of an electronic flow meter in the on-site equipment.

[0018] A further characteristic configuration of the combustion control system is a combustion control system including the above-mentioned flow control system, and a burner to which the fuel gas flowing through the on-site fuel piping and the combustion gas flowing through the on-site combustion gas piping are introduced, the burner comprising: In the on-site facility, the abnormality determination unit determines whether or not there is an abnormality in the flow rate control by using the pressure-fuel-flow rate relationship that is common to different types of burners.

[0019] According to the above characteristic configuration, even if burners having different pressure losses are used in the on-site equipment, the pressure at the secondary outlet of the flow control valve can be controlled to a constant value by the secondary pressure adjustment mechanism, thereby eliminating the influence of different pressure losses of different burners, and a common pressure-fuel-flow relationship can be used to determine flow control abnormalities for the different types of burners, making it possible to build a simple and economical system that does not require the installation of an electronic flow meter in the on-site equipment.

[0020] A further characteristic configuration of the flow control system is The blower for pressure-feeding the combustion gas is used in common as the primary fuel pressure adjustment mechanism.

[0021] According to the above-described characteristic configuration, the blower for pressurizing combustion gas to the burner can also be used as the primary fuel pressure adjustment mechanism for controlling the flow rate of fuel gas, thereby simplifying the configuration compared to the case where a dedicated device is provided as the primary fuel pressure adjustment mechanism. [Brief description of the drawings]

[0022] [Figure 1] 1 is a schematic configuration diagram of a combustion control system according to an embodiment; [Diagram 2] FIG. 1 is a schematic configuration diagram showing a test facility according to an embodiment. [Diagram 3] FIG. 11 is a graph showing the relationship between opening degree and air flow rate for combustion air. [Figure 4] FIG. 2 is a graph showing the relationship between the pressure and the air flow rate of combustion air. [Diagram 5] FIG. 4 is a graph showing the relationship between the head pressure and the flow rate of the burner. [Figure 6] FIG. 13 is a graph showing the relationship between opening degree and fuel flow rate in the case of fuel gas. [Figure 7] FIG. 4 is a graph showing the relationship between pressure and fuel flow rate of fuel gas. [Figure 8] FIG. 11 is a schematic configuration diagram of a combustion control system according to another embodiment. [Figure 9] 4 is a graph showing changes over time in the opening degree of a fuel flow control valve and a pressure regulating valve serving as a secondary pressure regulating mechanism when controlling the flow rate of fuel gas in the combustion control system according to the embodiment. FIG. [Figure 10] FIG. 4 is a graph showing changes over time in primary pressure and secondary pressure of a fuel flow control valve when controlling the flow rate of fuel gas in the combustion control system according to the embodiment. [Figure 11] 4 is a graph showing a change over time in the flow rate of fuel gas when the flow rate of fuel gas is controlled in the combustion control system according to the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The flow control systems 100, 200 and the combustion control system 300 according to the embodiments of the present invention maintain a simple configuration without a flow meter, improving economy, while preventing unintended combustion during adjustments, etc., and safely realizing labor savings by automating various adjustments of the fuel gas flow rate, etc. Hereinafter, flow rate control systems 100, 200 and a combustion control system 300 according to the embodiments will be described with reference to Figs.

[0024] As shown in FIG. 1, the combustion control system 300 according to this embodiment is configured to include a flow control system 100 for a fuel gas G, such as city gas 13A, a flow control system 200 for combustion air A (an example of a combustion gas) as an oxidizer for the fuel gas G, a control device S realized in a form in which hardware and software work together, and a burner BNa, and is configured to heat the inside of an industrial furnace R to a predetermined temperature.

[0025] <Flow rate control system 100 for fuel gas G> As shown in FIG. 1, the flow rate control system 100 for fuel gas G is provided in an on-site fuel piping H1 through which fuel gas G as a gas to be controlled flows, and includes a fuel flow rate control valve RVg whose opening is controlled by a control command from a flow rate control unit S1 as a control device S, a secondary-side fuel pressure regulating mechanism GV that is provided at the outlet of the fuel flow rate control valve RVg in the on-site fuel piping H1 and that is capable of adjusting the pressure of the secondary-side outlet based on a measurement result of a second fuel pressure gauge P2g provided at the secondary-side outlet of the fuel flow rate control valve RVg, and a first fuel pressure gauge P2g provided at the primary-side inlet of the fuel flow rate control valve RVg in the on-site fuel piping H1. The system is equipped with an inverter-type blower B as a primary side fuel pressure adjustment mechanism capable of adjusting the pressure at the primary side inlet based on the measurement results of the pressure gauge P1g, a first solenoid valve SV1 and a second solenoid valve SV2 as fuel pipe opening / closing valves provided at the most upstream position on the primary side of the on-site fuel pipe H1 for opening and closing the on-site fuel pipe H1, and an air flow control valve RVa as a combustion gas pipe opening / closing valve provided in an on-site air pipe H2 (an example of an on-site combustion gas pipe) through which combustion air A flows, downstream of the blower B which pressurizes combustion air A to the on-site air pipe H2 for opening and closing the on-site air pipe H2. That is, in the field equipment 100a, the blower B serving as the primary fuel pressure adjustment mechanism has a common configuration with the blower B that pressure-feeds the combustion air A to the field air piping H2.

[0026] Furthermore, the flow control system 100 for the fuel gas G is provided in a field connection pipe H3 that connects the primary side of the fuel flow control valve RVg of the field fuel pipe H1 and the secondary side of the first solenoid valve SV1 and the second solenoid valve SV2 with the primary side of the air flow control valve RVa of the field air pipe H2 and the secondary side of the blower B, and is provided with a connection pipe opening / closing valve SV3 that opens and closes the field connection pipe H3, and is provided with a memory unit S3 that stores an opening-fuel flow rate relationship (shown in FIG. 6) between the opening of the fuel flow control valve RVg and the flow rate of the fuel gas G flowing through the field fuel pipe H1, a flow control unit S1 that controls the flow rate of the fuel gas G by the fuel flow control valve RVg, and a pressure control unit S4 that controls the pressure by the secondary side fuel pressure adjustment mechanism GV and the blower B as the primary side fuel pressure adjustment mechanism, as will be described later. The memory unit S3, the flow control unit S1, and the pressure control unit S4 are realized in the control device S by the cooperation of hardware such as a CPU and a memory and software.

[0027] Here, the overall configuration of the flow control system 100 for the fuel gas G, i.e., the configuration of the combustion control system 300, will be explained. A burner BNa is provided to heat the inside of the industrial furnace R, and the flow control unit S1 of the above-mentioned control device S controls the flow rates of the fuel gas G and combustion air A led to the burner BNa so that the measured temperature measured by the temperature sensor ND that measures the temperature inside the industrial furnace R becomes the target temperature. In the on-site equipment 100a, an on-site fuel pipe H1 that leads fuel gas G to a burner BNa is provided with, in order from the downstream side (secondary side), a secondary side fuel pressure adjustment mechanism GV, a second fuel pressure gauge P2g, a fuel flow control valve RVg, a first fuel pressure gauge P1g, a governor GA that can adjust the primary side pressure of the fuel flow control valve RVg to a predetermined set pressure, a first solenoid valve SV1, and a second solenoid valve SV2. The on-site air piping H2, which leads combustion air A to the burner BNa, is provided with, in order from the downstream side (secondary side), a third air pressure gauge P3a, a pressure regulating valve BVa, a second air pressure gauge P2a, an air flow control valve RVa, a first air pressure gauge P1a, and a blower B. Here, the third air pressure gauge P3a measures the head pressure of the burner BNa at the primary inlet of the burner BNa of the on-site air piping H2, and is configured to check whether the relationship between the head pressure and the flow rate for each of burners 1 to 3 is consistent with known values, as shown in Figure 5.

[0028] Next, a test facility 400 for acquiring the opening-fuel flow rate relationship stored in the memory unit S3 will be described with reference to Fig. 2. Note that, in the test facility 400, control lines from various pressure gauges are not shown due to space limitations. The test equipment 400 is provided with a test fuel pipe H1x having the same diameter as the on-site fuel pipe H1 in place of the on-site fuel pipe H1, a test air pipe H2x having the same diameter as the on-site air pipe H2 in place of the on-site air pipe H2, and a test connection pipe H3x having the same diameter as the on-site connection pipe H3 in place of the on-site connection pipe H3, each of which is provided in the on-site equipment 100a, and is also provided with a first flow meter F1 (an example of a fuel flow meter) that measures the flow rate of fluid flowing through the test fuel pipe H1x. Here, the on-site facility 100a is provided with the following components in the test fuel pipe H1x that introduces the fuel gas G to the burner BNa, in order from the downstream side (secondary side): a secondary fuel pressure adjustment mechanism GV, a second fuel pressure gauge P2g, a fuel flow control valve RVg, a first fuel pressure gauge P1g, a governor GA that can adjust the pressure of the primary side of the fuel flow control valve RVg to a predetermined set pressure, a first solenoid valve SV1, and a second solenoid valve SV2. Furthermore, in the test air pipe H2x (an example of a test combustion gas pipe) that introduces the combustion air A to the burner BNa, in order from the downstream side (secondary side), a third air pressure gauge P3a, a pressure adjustment valve BVa, a second air pressure gauge P2a, an air flow control valve RVa, a first air pressure gauge P1a, and a blower B, and a flow control unit Ss1, a memory unit Ss3, and a pressure control unit Ss4 are provided as the control device Ss. In addition, as a configuration for obtaining the opening air flow rate relationship in the flow control system 200 for the combustion air A described below, the test air piping H2x is equipped with a second flow meter F2 that measures the flow rate of the fluid flowing through the test air piping H2x.

[0029] In order to obtain the opening-fuel flow rate relationship, in the test facility 400, the flow rate control unit Ss1 and pressure control unit Ss4 of the control device Ss close the air flow rate control valve RVa, the first solenoid valve SV1, and the second solenoid valve SV2 and open the connecting pipe opening / closing valve SV3, and operate the blower B to flow the combustion air A through the test fuel pipe H1x via the test connecting pipe H3x, maintain the fuel flow rate control valve RVg at a predetermined initial setting opening (for example, 100%), and maintain the pressure of the primary side inlet at a predetermined fuel flow rate control pressure (maintained at 6 kPa ± 0.05 kPa for 30 seconds) using the blower B. Then, the pressure of the secondary side outlet is set to a predetermined initial setting secondary pressure (maintained at 5 kPa ± 0.05 kPa for 30 seconds) using the secondary side fuel pressure adjustment mechanism GV, and the opening-fuel flow rate relationship is obtained as the relationship between the opening of the fuel flow rate control valve RVg and the flow rate measured by the first flow meter F1.

[0030] Incidentally, in the case of acquiring the above-mentioned opening-fuel flow rate relationship in the test facility 400, the opening of the fuel flow rate control valve RVg and the secondary side fuel pressure regulating mechanism GV change over time as shown in FIG. 9, the primary pressure and secondary pressure of the fuel flow rate control valve RVg change as shown in FIG. 10, and the flow rate of the combustion air A flowing through the test fuel pipe H1x changes as shown in FIG. 11. In addition, when obtaining the opening-fuel flow rate relationship, since the combustion air A is flowing instead of the fuel gas G, the flow rate control unit Ss1 derives the opening-fuel flow rate relationship using a corrected fuel flow rate Q' obtained by correcting the flow rate Q measured by the first flow meter F1 using the conversion formula shown in the following [Formula 1], where s is the specific gravity of the fuel gas G. Q'=Q / √s (Equation 1)

[0031] As described above, the flow rate control system 100 for the fuel gas G executes the following control using the opening-fuel flow rate relationship acquired by the test facility 400. That is, in the on-site equipment 100a, the flow rate control section S1 and pressure control section S4 of the control device S close the air flow rate control valve RVa, the first solenoid valve SV1, and the second solenoid valve SV2 and open the connecting piping on-off valve SV3, while operating the blower B to flow the combustion air A through the on-site fuel piping H1 via the on-site connecting piping H3, maintaining the fuel flow rate control valve RVg at a predetermined initial setting opening (for example, 100%) and maintaining the pressure of the primary side inlet at a predetermined fuel flow rate control pressure (maintaining 6 kPa ± 0.05 kPa for 30 seconds) with the secondary side fuel pressure adjustment mechanism GV, and then stopping the blower B and closing the connecting piping on-off valve SV3. Thereafter, the first solenoid valve SV1 and the second solenoid valve SV2 are opened, and the opening of the fuel flow control valve RVg is controlled based on the opening-fuel flow rate relationship (shown in FIG. 6) stored in the memory unit S3, to control the flow rate of the fuel gas G to a target flow rate.

[0032] Incidentally, in order to prevent the fuel gas G from flowing into the on-site air pipe H2 and the test air pipe H2x, which are pipes through which the combustion air A flows, the on-site connection pipe H3 is provided with a first check valve GV3 downstream of the connection pipe opening / closing valve SV3, which blocks the flow of the fuel gas G from the on-site fuel pipe H1 to the on-site air pipe H2 in the flow direction of the combustion air A in the on-site connection pipe H3. Also, the test connection pipe H3x is provided with a second check valve GV3, which blocks the flow of the fuel gas G from the test fuel pipe H1x to the test air pipe H2x in the flow direction of the combustion air A in the test connection pipe H3x. Furthermore, in order to isolate the on-site fuel pipe H1 from the on-site air pipe H2, or the test fuel pipe H1x from the test air pipe H2x when fuel gas G is being supplied to the on-site fuel pipe H1 or the test fuel pipe H1x, an interlock mechanism (not shown) is provided in the on-site equipment 100a and the test equipment 400 to maintain the connecting pipe opening / closing valve SV3 in a closed state when the first solenoid valve SV1 and the second solenoid valve SV2 are in an open state.

[0033] In the flow control system 100 for fuel gas G described above, as the system is continued to be used, deviations may occur in the set openings of the various valve elements, causing the flow rate controlled based on the opening-fuel flow rate relationship to deviate from the target flow rate. Then, in the test facility 400, the memory unit S3 stores the pressure-fuel flow rate relationship (shown in FIG. 7 ) between the pressure of the secondary outlet measured by the second fuel pressure gauge P2g and the flow rate measured by the first flow meter F1 after the flow rate control unit Ss1 and the pressure control unit Ss4 of the control device Ss close the air flow control valve RVa, the first solenoid valve SV1, and the second solenoid valve SV2 and open the connection pipe opening / closing valve SV3, operate the blower B to flow the combustion air A into the test fuel pipe H1x via the test connection pipe H3x, maintain the fuel flow control valve RVg at a predetermined initial setting opening (for example, 100%), and maintain the pressure of the primary inlet at a predetermined fuel flow control pressure by the blower B (maintain 6 kPa±0.05 kPa for 30 seconds), and then set the pressure of the secondary outlet by the secondary fuel pressure adjustment mechanism GV to a predetermined initial setting secondary pressure (maintain 5 kPa±0.05 kPa for 30 seconds). Furthermore, in the field equipment 100a, when the flow control unit S1 of the control device S stops the blower B and closes the connecting piping on-off valve SV3, and then opens the first solenoid valve SV1 and the second solenoid valve SV2 to control the opening of the fuel flow control valve RVg according to the opening-fuel flow rate relationship (shown in FIG. 6) to control the flow rate of the fuel gas G to a target flow rate, if the controlled flow rate of the fuel gas G differs from the flow rate derived from the pressure of the secondary outlet measured by the second fuel pressure gauge P2g and the pressure-fuel flow rate relationship (shown in FIG. 7), the field equipment 100a is provided with an abnormality determination unit S2 which determines that a flow control abnormality has occurred. When the abnormality determination unit S2 determines that there is an abnormality in the flow control and this is displayed on a display unit (not shown) such as a monitor, the manager executes various settings of the flow control system 100 related to the fuel gas G again.

[0034] <Flow rate control system 200 for combustion air A> In the flow control system 200 for the combustion air A, the flow rate of the combustion air A is controlled by flowing the combustion air A through the on-site air piping H2 and the test air piping H2x using the acquired opening-air flow rate relationship (shown in FIG. 3). In the flow control system 200 for the combustion air A, in order to obtain the opening-air flow rate relationship, in the test facility 400, the flow control unit Ss1 and the pressure control unit S4 of the control device Ss close the connecting pipe opening / closing valve SV3, operate the blower B to pass the combustion air A through the test air pipe H2x, maintain the air flow control valve RVa at a predetermined initial opening (for example, 100%), and maintain the pressure of the primary side inlet at a predetermined air flow control pressure (maintain 8.0 kPa ± 0.05 kPa for 30 seconds) with the blower B, and set the pressure of the secondary side outlet to a predetermined initial secondary pressure (maintain 4.0 kPa ± 0.05 kPa for 30 seconds) with the pressure control valve BVa as the secondary side air pressure adjustment mechanism, and then obtain the opening-air flow rate relationship (shown in FIG. 3) as the relationship between the opening of the air flow control valve RVa and the flow rate measured by the second flow meter F2. As described above, using the opening degree / air flow rate relationship acquired by the test facility 400, the flow rate control system 200 for the combustion air A executes the following control. That is, in the on-site equipment 200a, the flow rate control section S1 and pressure control section S4 of the control device S close the connecting piping on-off valve SV3, operate the blower B to flow the combustion air A through the on-site air piping H2, maintain the air flow rate control valve RVa at a predetermined initial setting opening (for example, 100%), and maintain the pressure of the primary side inlet at a predetermined air flow rate control pressure (maintaining 8.0 kPa ± 0.05 kPa for 30 seconds) with the blower B, set the pressure of the secondary side outlet at a predetermined initial setting secondary pressure (maintaining 4.0 kPa ± 0.05 kPa for 30 seconds) with the pressure regulating valve BVa, and then control the flow rate of the combustion air A to a target flow rate by controlling the opening of the air flow rate control valve RVa based on the opening air flow rate relationship (in FIG. 3) stored in the memory section S3.

[0035] In the flow control system 200 for the combustion air A, as use continues, deviations may occur in the set openings of the various valve elements, causing the flow rate controlled based on the opening-air flow rate relationship to deviate from the target flow rate. Therefore, in the test facility 400, the flow control unit Ss1 and the pressure control unit Ss4 of the control device Ss close the connecting pipe opening / closing valve SV3, operate the blower B to pass the combustion air A through the test air pipe H2x, maintain the air flow control valve RVa at a predetermined initial setting opening (for example, 100%), and maintain the pressure of the primary side inlet at a predetermined air flow control pressure by the blower B (maintain 8.0 kPa ± 0.05 kPa for 30 seconds), and then set the pressure of the secondary side outlet to a predetermined initial setting secondary pressure by the pressure control valve BVa as the secondary side air pressure adjustment mechanism (maintain 4.0 kPa ± 0.05 kPa for 30 seconds). The field equipment 200a stores a pressure-air flow rate relationship (shown in FIG. 4) between the pressure of the secondary outlet measured by the air pressure gauge P2a and the flow rate measured by the second flow meter F2. When the flow rate control unit S1 of the control device S closes the connecting piping on-off valve SV3 and controls the opening of the air flow control valve RVa according to the opening-air flow rate relationship (shown in FIG. 3) to control the flow rate of the combustion air A to a target flow rate, if the controlled flow rate of the combustion air A differs from the flow rate derived from the pressure of the secondary outlet measured by the second air pressure gauge P2a and the pressure-air flow rate relationship (shown in FIG. 4), the field equipment 200a is provided with an abnormality determination unit S2 which determines that a flow rate control abnormality has occurred. When the abnormality determination unit S2 determines that there is an abnormality in the flow control and this is displayed on a display unit (not shown) such as a monitor, the manager executes various settings of the flow control system 200 related to the combustion air A again.

[0036] Now, in the combustion control system 300 having a burner BNa equipped with the above-mentioned flow control system 100 for the fuel gas G and the flow control system 200 for the combustion air A, in the on-site equipment 100a, 200a, the flow control unit S1 of the control device S controls the flow rate of the fuel gas G using a common opening / fuel flow rate relationship for different types of burners BNa, and controls the flow rate of the combustion air A using a common opening / air flow rate relationship for different types of burners BNa. That is, the opening / fuel flow rate relationship has a common relationship for the burners BNa with different head pressures as shown in Fig. 6, so that one opening / fuel flow rate relationship can be used in various sites. Also, the opening / air flow rate relationship has a common relationship for the burners BNa with different head pressures as shown in Fig. 3, so that one opening / air flow rate relationship can be used in various sites.

[0037] Furthermore, in the combustion control system 300, in the on-site equipment 100a, 200a, the abnormality determination unit S2 determines whether there is an abnormality in the flow control of the fuel gas G using a common pressure-fuel flow relationship for different types of burners BNa, and also determines whether there is an abnormality in the flow control of the combustion air A using a common pressure-air flow relationship for different types of burners BNa. That is, the pressure-fuel flow rate relationship has a common relationship for the burners BNa with different head pressures as shown in Fig. 7, so that one pressure-fuel flow rate relationship can be used in various sites. Also, the pressure-air flow rate relationship has a common relationship for the burners BNa with different head pressures as shown in Fig. 4, so that one pressure-air flow rate relationship can be used in various sites.

[0038] [Another embodiment] (1) In the above embodiment, the combustion air A is exemplified as the combustion gas. However, for example, an oxygen-enriched gas that is enriched with oxygen may be used as the combustion gas.

[0039] (2) The combustion control system 300 is not limited to use in heating the industrial furnace R, but can be widely applied to burners in glass melting furnaces, metal forging facilities, and the like.

[0040] (3) Although not described in detail in the above embodiment, in an environment in which the temperature of the field equipment 100a, 200a changes significantly, the following configuration and control may be adopted. That is, in the test equipment 400, the opening-fuel flow rate relationship can be obtained for each temperature of the fuel gas G flowing through the test fuel pipe H1x, and in the on-site equipment 100a, flow rate control of the fuel gas G and the combustion air A can be performed based on the opening-fuel flow rate relationship at the temperature of the fuel gas G measured in the on-site fuel pipe H1. In addition, in the test equipment 400, the opening / air flow rate relationship can be obtained for each temperature of the combustion air A flowing through the test air piping H2x, and in the on-site equipment 200a, flow rate control of the combustion air A can be performed based on the opening / air flow rate relationship at the temperature of the combustion air A measured in the on-site air piping H2.

[0041] (4) In the above embodiment, a governor GA may be used as the secondary fuel pressure regulating mechanism GV. In this case, as shown in FIG. 8, the connection point of the field connection piping H3 of the field equipment 100a with the field fuel piping H1 is connected between the governor GA and the first solenoid valve SV1, and the discharge pressure of the blower B is controlled to a constant value.

[0042] In the above embodiment, a configuration example has been shown in which the air flow control valve RVa is used as the combustion gas piping on-off valve, but a configuration may be adopted in which an on-off valve is provided in addition to the air flow control valve RVa.

[0043] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, provided that no contradiction arises. Furthermore, the embodiments disclosed in this specification are merely examples, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope that does not deviate from the purpose of the present invention. [Industrial Applicability]

[0044] The flow control system of the present invention and a combustion control system equipped with the same can be effectively used as a fluid flow control system and a combustion control system equipped with the same, which can prevent unintended combustion and the like during adjustments, while improving economy by maintaining a simple configuration without a flow meter, and can safely achieve labor savings by automating various adjustments of the fuel gas flow rate, etc. [Explanation of symbols]

[0045] 100, 200: Flow control system 100a, 200a: Field equipment 300: Combustion control system 400: Testing facilities A: Combustion air B: Blower BNa: Burner F1: 1st flow meter F2: 2nd flow meter G: Fuel gas GV: Secondary fuel pressure adjustment mechanism GV3: 1st check valve, 2nd check valve H1: On-site fuel piping H1x: Test fuel pipe H2: On-site air piping H2x: Test air piping H3: On-site connection piping H3x: Test connection pipe P1g: 1st fuel pressure gauge P2g: Second fuel pressure gauge Q:Flow rate Q' :Fuel flow rate after correction RVg: Fuel flow control valve S: Control device S1: Flow control section S2: Abnormality determination section S3: Storage section S4: Pressure control section SV1: First solenoid valve SV2: Second solenoid valve SV3: Connection piping on-off valve RVa: Air flow control valve

Claims

1. A flow rate control system for controlling a flow rate of a control target gas including a fuel gas, a fuel flow control valve that is provided in an on-site fuel pipe through which the fuel gas as the gas to be controlled flows, and whose opening degree is controlled by a control command from a flow control unit; a secondary-side fuel pressure regulating mechanism that is provided at an outlet of the fuel flow control valve in the on-site fuel piping and that is capable of adjusting a pressure of the secondary-side outlet based on a measurement result of a second fuel pressure gauge that is provided at a secondary-side outlet of the fuel flow control valve; a primary-side fuel pressure regulating mechanism that is provided at a primary-side inlet of the fuel flow control valve in the on-site fuel piping and that is capable of adjusting a pressure of the primary-side inlet based on a measurement result of a first fuel pressure gauge; a fuel pipe opening / closing valve provided at a most upstream portion of a primary side of the on-site fuel pipe for opening and closing the on-site fuel pipe; a blower that is provided in an on-site combustion gas pipe through which a combustion gas as an oxidizer for the fuel gas flows and that pressure-feeds the combustion gas into the on-site combustion gas pipe; and a combustion gas pipe opening / closing valve that is located downstream of the blower and that is capable of opening and closing the on-site combustion gas pipe; a connecting pipe opening / closing valve that is provided in a field connection pipe that connects a primary side of the fuel flow control valve and a secondary side of the fuel pipe opening / closing valve of the field fuel pipe with a primary side of the combustion gas pipe opening / closing valve and a secondary side of the blower of the field combustion gas pipe, and opens and closes the field connection pipe, In a test facility including a test fuel pipe having the same diameter as the on-site fuel pipe in place of the on-site fuel pipe, a test combustion gas pipe having the same diameter as the on-site combustion gas pipe in place of the on-site combustion gas pipe, and a test connection pipe having the same diameter as the on-site connection pipe in place of the on-site connection pipe, the test facility is provided with a fuel flow meter for measuring a flow rate of a fluid flowing through the test fuel pipe, and the pressure control unit and the flow rate control unit for controlling pressure by the secondary side fuel pressure adjustment mechanism and the primary side fuel pressure adjustment mechanism are provided with the combustion gas pipe opening / closing valve and the a storage unit that stores an opening / fuel flow rate relationship between the opening of the fuel flow control valve and a flow rate measured by the fuel flow meter, after the fuel pipe opening / closing valve is closed and the connection pipe opening / closing valve is opened, the blower is operated to cause the combustion gas to flow into the test fuel pipe via the test connection pipe, the fuel flow control valve is maintained at a predetermined initial setting opening, and the pressure of the primary side inlet is maintained at a predetermined fuel flow control pressure by the primary side fuel pressure regulating mechanism, and then the pressure of the secondary side outlet is set to a predetermined initial setting secondary pressure by the secondary side fuel pressure regulating mechanism, a flow control system in which, in the on-site facility, the pressure control unit and the flow rate control unit close the combustion gas piping on-off valve and the fuel piping on-off valve and open the connecting piping on-off valve, operate the blower to flow the combustion gas into the on-site fuel piping via the on-site connecting piping, maintain the fuel flow control valve at a predetermined initial setting opening, and, in a state in which the pressure of the primary side inlet is maintained at a predetermined fuel flow control pressure by the primary side fuel pressure regulating mechanism, the pressure of the secondary side outlet is set to a predetermined initial setting secondary pressure by the secondary side fuel pressure regulating mechanism, after which the fuel piping on-off valve is opened and the connecting piping on-off valve is closed, and the opening of the fuel flow control valve is controlled to control the flow rate of the fuel gas to a target flow rate based on the opening fuel flow rate relationship stored in the memory unit.

2. The on-site connection pipe is provided with a first check valve that prevents the fuel gas from flowing from the on-site fuel pipe to the on-site combustion gas pipe; 2. The flow control system according to claim 1, wherein the test connection pipe is provided with a second check valve that prevents the fuel gas from flowing from the test fuel pipe to the test combustion gas pipe.

3. 3. The flow control system according to claim 1, wherein an interlock mechanism is provided in the field facility and the test facility to maintain the connection pipe opening / closing valve in a closed state when the fuel pipe opening / closing valve is in an open state.

4. The flow control system according to any one of claims 1 to 3, wherein the flow control unit derives the opening-fuel flow rate relationship by using a corrected fuel flow rate Q' obtained by correcting the flow rate Q measured by the fuel flow meter using a conversion formula shown in the following [Formula 1], where s is a specific gravity of the fuel gas. Q′=Q / √s (Formula 1)

5. the memory unit stores a pressure-fuel-flow rate relationship between the pressure of the secondary outlet measured by the second fuel pressure gauge and the flow rate measured by the fuel flow meter after the pressure of the secondary outlet is set to a predetermined initial setting secondary pressure by the secondary fuel pressure regulating mechanism in a state in which, in the test facility, the pressure control unit and the flow rate control unit close the combustion gas piping on-off valve and the fuel piping on-off valve and open the connection piping on-off valve, operate the blower to flow the combustion gas into the test fuel piping via the test connection piping, maintain the fuel flow control valve at a predetermined initial setting opening, and maintain the pressure of the primary inlet at a predetermined fuel flow control pressure by the primary fuel pressure regulating mechanism, 5. The flow control system according to claim 1, further comprising an abnormality determination unit that determines that a flow control abnormality has occurred when, in the on-site facility, when the flow control unit controls the fuel gas flow rate to the target flow rate by controlling an opening of the fuel flow control valve according to the opening-fuel-flow rate relationship with the fuel piping on-off valve in an open state and the connecting piping on-off valve in a closed state, the controlled flow rate of the fuel gas differs from a flow rate derived from the pressure of the secondary side outlet measured by the second fuel pressure gauge and the pressure-fuel-flow rate relationship.

6. A combustion control system comprising the flow control system according to any one of claims 1 to 5, and a burner to which the fuel gas flowing through the on-site fuel piping and the combustion gas flowing through the on-site combustion gas piping are introduced, the burner comprising: In the on-site facility, the flow rate control unit controls the flow rate of the fuel gas using the opening-fuel flow rate relationship that is common to different types of burners.

7. A combustion control system comprising the flow control system according to claim 5 and a burner to which the fuel gas flowing through the on-site fuel piping and the combustion gas flowing through the on-site combustion gas piping are introduced, the burner comprising: In the on-site facility, the abnormality determination unit determines whether or not there is an abnormality in the flow rate control by using the pressure-fuel-flow rate relationship that is common to different types of burners.

8. 8. The combustion control system according to claim 6, wherein the blower for pumping the combustion gas is also used as the primary fuel pressure adjustment mechanism.

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