JP6673863B2 - Mixture supply device and combustion device - Google Patents

Description

  Embodiments of the present invention relate to an air-fuel mixture supply device and a combustion device.

  Some conventional combustors introduce a premixed gas mixture of fuel and air in advance into a combustion region and burn the mixture. In such a premixed combustion type combustor, if the flow rate of combustion air decreases for some reason and the air ratio deviates from the set range, the equivalence ratio, which is the mixing ratio of fuel and air, deviates from the set range. Becomes The deviation from the set range of the equivalence ratio causes, for example, unstable combustion or an increase in nitrogen oxides (NOx) in the combustion gas.

  Therefore, a conventional premixed combustion type combustor is provided with an air-fuel mixture supply device that provides a flow rate adjusting means such as a pressure equalizing valve in a fuel supply path for supplying fuel and adjusts a fuel flow rate according to a change in an air ratio. ing. The pre-mixture formed in the mixture supply device is introduced into the combustor.

  As an air-fuel mixture supply device having such a pressure equalizing valve, there is an air-fuel mixture supply device in which a cylindrical mixing chamber is provided in a suction portion of a fan and fuel is supplied into the mixing chamber. In this mixing chamber, the air sucked from one end of the mixing chamber and the fuel sucked into the mixing chamber are uniformly mixed by operating the fan. Then, the mixed air-fuel mixture is sucked into the fan from the suction port of the fan, passes through the fan, and is introduced into the combustor.

  At this time, the equalizing valve adjusts the fuel supplied at the primary pressure to the secondary pressure and supplies the fuel to the combustor based on the signal pressure introduced to the equalizing valve. Here, the signal pressure is a pressure acting on the diaphragm in the equalizing valve to adjust the secondary pressure to a pressure corresponding to the signal pressure. As the signal pressure, for example, a static pressure of a mixing chamber that sucks air is used. Since the pressure in the mixing chamber is a negative pressure, the signal pressure is a negative pressure. Further, the secondary pressure of the fuel also becomes a negative pressure. Here, the negative pressure means a gauge pressure with the atmospheric pressure set to 0 atm and a pressure lower than the atmospheric pressure (hereinafter the same).

  The configuration of the pressure equalizing valve 300 used in such a conventional air-fuel mixture supply apparatus having a negative pressure type mixing chamber will be described.

  FIG. 7 is a diagram schematically showing a longitudinal section of a pressure equalizing valve 300 used in a conventional air-fuel mixture supply device having a negative pressure type mixing chamber.

  As shown in FIG. 7, the equalizing valve 300 adjusts the pressure difference between the valve body 310 for adjusting the opening degree of the gas passage, the signal pressure P13 which is the static pressure of the mixing chamber for sucking air, and the outlet pressure P12 of the equalizing valve 300. It includes a receiving diaphragm 311, a valve element 310, a spring 312 for supporting the diaphragm 311 and an adjusting mechanism 313 for adjusting the spring 312.

  For example, when the rotation speed of the fan increases and the signal pressure P13 fluctuates more to the negative pressure side, the diaphragm 311 is pulled toward the adjusting mechanism 313 (lower side in FIG. 7) with the pressure fluctuation, and the valve body 310 moves downward. Then, the outlet pressure P12 of the pressure equalizing valve 300 is adjusted so as to be the signal pressure P13 which fluctuates to the negative pressure side. Thereby, the flow rate of the fuel introduced into the mixing chamber increases.

  As described above, in the conventional combustor, the static pressure of the mixing chamber or the like is used as the signal pressure P13 of the equalizing valve 300, and the fuel flow rate is changed in accordance with the air flow rate change. The mixing ratio is kept constant.

JP 2010-127541 A

  As described above, when the fuel supply pressure is maintained by using the equalizing valve, the static pressure of the mixing chamber or the like is conventionally used as the signal pressure. Here, at a low output load, the static pressure which is the signal pressure P13 is also small, and it is difficult to control an appropriate fuel flow rate.

  Therefore, in a conventional air-fuel mixture supply device having a negative pressure type mixing chamber, adjustment is performed by adjusting the adjusting mechanism 313 to secure a fuel flow rate at a low output load. Therefore, at the time of a high output load, a fuel flow rate larger than an appropriate fuel flow rate may be discharged from the equalizing valve 300. This makes it difficult to maintain a constant fuel / air mixture ratio at each output load.

  An object of the present invention is to provide an air-fuel mixture supply device and a combustion device capable of maintaining a constant fuel-air mixture ratio at each output load.

  The air-fuel mixture supply device of the embodiment supplies a premixed air-fuel mixture to a combustor. The air-fuel mixture supply device includes a fan that blows the pre-air-fuel mixture to the combustor, a mixer connected at one end to a suction port of the fan, a mixer that mixes fuel and air, and a fuel that is connected to the mixer. A fuel supply pipe for supplying the inside of the mixer, a cylinder connected to the other end of the mixer, and having a negative pressure inside due to a suction force generated by the blowing of the fan, and an opening end of the cylinder. A rectifying unit for rectifying air introduced into the cylinder, a total pressure detecting unit for detecting a total pressure of air sucked into the cylinder via the rectifying unit, and a rectifying unit interposed in the fuel supply pipe. A fuel flow adjusting unit for adjusting fuel supplied at a primary pressure to a secondary pressure based on the total pressure detected by the total pressure detecting unit and discharging the fuel to the mixer side.

  According to the air-fuel mixture supply device and the combustion device of the present invention, the mixing ratio of fuel and air can be kept constant at each output load.

It is a figure showing typically the outline of the combustion device provided with the air-fuel mixture supply device of an embodiment. It is the figure which expanded and showed some cross sections of the air-fuel mixture supply apparatus of embodiment typically. It is the figure which showed typically the longitudinal cross section of the fuel flow control part with which the air-fuel mixture supply apparatus of embodiment is provided. It is a figure showing an example of a database of a set fuel flow rate corresponding to a fan rotation number of an air-fuel mixture supply device of an embodiment. It is a flowchart of the abnormality detection processing in the air-fuel mixture supply device of the embodiment. It is the figure which showed the pressure change of total pressure, static pressure, and dynamic pressure in the cylinder of the air-fuel mixture supply apparatus with respect to the output load of a combustor. It is the figure which showed typically the longitudinal section of the pressure equalizing valve used for the air-fuel mixture supply apparatus provided with the conventional negative pressure type mixing chamber.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram schematically illustrating an outline of a combustion apparatus 1 including an air-fuel mixture supply device 10 according to an embodiment. FIG. 2 is a diagram schematically showing an enlarged cross section of a part of the air-fuel mixture supply device 10 according to the embodiment. FIG. 3 is a diagram schematically illustrating a vertical cross section of a fuel flow rate adjusting unit 70 provided in the air-fuel mixture supply device 10 according to the embodiment.

  As shown in FIG. 1, the combustion device 1 includes an air-fuel mixture supply device 10 and a combustor 100.

  The air-fuel mixture supply device 10 uniformly mixes fuel (gas fuel) and air to form a pre-air-fuel mixture. The mixture supply device 10 includes a fan 20, a mixer 30, a fuel supply pipe 40, a cylinder 50, a total pressure detection unit 60, a fuel flow rate adjustment unit 70, a control unit 90, an operation panel 150, Is provided.

  As shown in FIG. 2, the fan 20 includes a casing 21, in which, for example, a rotating blade 22 is provided. Further, the fan 20 includes a motor 23 for rotating the rotary blade 22. In the casing 21 of the fan 20, a suction port 24 for sucking the premixed gas from the mixer 30 and a discharge port 25 for discharging the sucked premixed gas are formed inside the fan 20.

  Further, the fan 20 is provided with, for example, a fan tachometer 26 for detecting the number of revolutions of the fan 20. Note that the fan tachometer 26 functions as a tachometer. The fan 20 is composed of, for example, a sirocco fan or a turbo fan.

  The outlet 25 of the fan 20 communicates with a premixed gas introduction space 102 of the combustor 100 described below directly or via a pipe or the like.

  The mixer 30 is constituted by a cylinder having a passage 31 therein. The mixer 30 is a so-called mixer. One end 32 of the mixer 30 is connected to the suction port 24 of the fan 20. Specifically, one end of the mixer 30 is connected to, for example, the casing 21 of the fan 20 such that the passage 31 of the mixer 30 communicates with the inside of the fan 20 via the suction port 24. Therefore, the premixed air and fuel that have passed through the mixer 30 are sucked into the fan 20 and further mixed.

  The passage 31 has a venturi structure having a throat portion 33 in which the cross-sectional area of the passage gradually decreases in the air flow direction (the direction of the arrow shown in FIG. 2). In the passage 31 downstream of the throat portion 33, for example, the cross-sectional area of the passage gradually increases in the flow direction.

  The fuel supply pipe 40 supplies the fuel (gas fuel) supplied from the fuel supply source 41 to the passage 31 of the mixer 30. One end 40a of the fuel supply pipe 40 communicates with the inside of the throat portion 33 of the passage 31, as shown in FIG.

  In the fuel supply pipe 40, a shutoff valve 42 for shutting off the flow of fuel in the fuel supply pipe 40 is provided on the mixer 30 side with respect to the fuel flow rate adjustment unit 70 and on the fuel supply source 41 side with respect to the fuel flow rate adjustment unit 70. , 43 are interposed. Further, for example, a fuel flow meter 44 for detecting a flow rate of the fuel flowing through the fuel supply pipe 40 is interposed between the shutoff valve 43 and the fuel supply source 41. Note that the fuel flow meter 44 functions as a fuel flow detecting unit.

  As shown in FIG. 2, the cylinder 50 connected to the other end 34 of the mixer 30 is, for example, a cylindrical body having both ends opened. A flow straightening plate 51 is provided at the opening end of the cylinder body 50 on a side different from the mixer 30 side. That is, the current plate 51 is provided at the opening end of the cylindrical body 50 on the upstream side in the air flow direction.

  Further, the cylinder 50 is provided with a pressure sensor 52 for detecting the pressure (static pressure) in the cylinder 50. The pressure sensor 52 is provided, for example, to detect that the pressure in the cylinder 50 has reached an abnormal range described later. Note that the pressure sensor 52 functions as a pressure detector.

  For example, as shown in FIG. 2, when the inner diameter of the cylinder 50 on the mixer 30 side is larger than the inner diameter of the other end 34 of the mixer 30, the end of the cylinder 50 on the mixer 30 side is The cross-sectional area may be configured in a tapered shape that gradually decreases toward the mixer 30. Thereby, pressure loss when air flows from the cylinder 50 to the mixer 30 can be suppressed.

  The rectifying plate 51 rectifies the flow of the air sucked into the cylindrical body 50 as the fan 20 blows air. The current plate 51 is formed of, for example, a flat plate such as a porous body, a honeycomb structure, or a punched metal. Note that the rectifying plate 51 functions as a rectifying unit.

  The total pressure detector 60 detects the total pressure of the combustion air sucked into the cylinder 50. As shown in FIGS. 1 and 2, the total pressure detecting unit 60 includes, for example, a tubular probe 61 and a transmission pipe 62 that transmits the total pressure detected by the probe 61 to the fuel flow rate adjusting unit 70. As shown in FIG. 2, the probe 61 has a total pressure detection port 63 that opens in the flow direction of the combustion air. Then, the flow is blocked at the total pressure detection port 63, and the total pressure of the flow is detected at the total pressure detection port 63.

  The probe 61 is arranged, for example, such that the center of the total pressure detection port 63 is located on the central axis of the cylindrical body 50. The probe 61 preferably has a small tube diameter so as not to obstruct the flow of air. Further, here, an example including one probe 61 is shown, but a plurality of probes 61 may be provided.

  In the case where a plurality of probes 61 are provided, for example, a probe 61 arranged so that the center of the total pressure detection port 63 is located on the central axis of the cylindrical body 50 and a probe 61 arranged outside the probe 61 in the radial direction. Probe 61 may be provided. That is, one probe may be provided on the central axis of the cylindrical body 50, and another probe 61 may be provided at a position radially outward from the central axis of the cylindrical body 50.

  In the case where a plurality of probes 61 are provided, the transmission pipe 62 communicating with each probe 61 may be one collecting pipe on the downstream side, and this collecting pipe may be connected to the fuel flow rate adjusting unit 70. In this case, the average pressure of the total pressure detected by the plurality of probes 61 is transmitted to the fuel flow rate adjusting unit 70.

  The fuel flow adjusting section 70 is interposed in the fuel supply pipe 40 as shown in FIG. The fuel flow rate adjusting section 70 adjusts the fuel supplied at the primary pressure to the secondary pressure based on the total pressure detected by the total pressure detecting section 60 and discharges the fuel to the mixer 30 side. The fuel flow rate adjusting unit 70 includes, for example, a pressure equalizing valve, a zero governor, and the like.

  As shown in FIG. 3, the fuel flow rate adjusting unit 70 includes a fuel inlet 71, a fuel outlet 72, and a signal pressure inlet 73. The signal pressure inlet 73 is connected to the transmission pipe 62 of the total pressure detector 60.

  The fuel flow rate adjusting unit 70 converts the fuel of the primary pressure (inlet pressure P1) introduced from the fuel inlet 71 into a secondary pressure (outlet) corresponding to the total pressure P3 which is the signal pressure introduced from the signal pressure inlet 73. The pressure is adjusted to P2) and discharged. That is, the pressure of the fuel discharged from the fuel discharge port 72 changes depending on the total pressure P3.

  A gas passage is formed in a casing 79 of the fuel flow rate adjusting unit 70, and a valve body 74, a diaphragm 75, a spring 76, and an adjusting mechanism 77 are provided. The valve 74 adjusts the opening of the gas passage.

  The diaphragm 75 forms a signal pressure chamber 80 inside the casing 79. The total pressure P3 introduced from the signal pressure inlet 73 is applied to the signal pressure chamber 80. Therefore, a full pressure P3 is applied to one of the diaphragms 75.

  A secondary pressure communication chamber 81 is formed on the other side of the diaphragm 75. The secondary pressure communication chamber 81 communicates with a fuel outlet 72 on the secondary side via a secondary pressure communication passage 82. Therefore, a pressure difference between the total pressure P3 and the outlet pressure P2 occurs in the diaphragm 75.

  The spring 76 supports the diaphragm 75, and the strength of the spring 76 is adjusted by the adjusting mechanism 77. Note that the fuel inlet 71 and the secondary pressure communication chamber 81 are partitioned by a partition film 83.

  The valve element 74 adjusts the degree of opening of the gas passage, and is connected to the diaphragm 75 via the valve rod 78. The valve rod 78 is provided so as to be slidable in the axial direction of the valve rod 78 with respect to the partition film 83. Further, between the valve stem 78 and the partition film 83, the fuel is prevented from leaking.

  The combustor 100 includes a casing 101 and a burner 103, as shown in FIG.

  A premixed gas introduction space 102 for introducing a premixed mixture of fuel and air discharged from the discharge port 25 of the fan 20 is provided below the casing 101. A burner 103 is provided above the premixed gas introduction space 102.

  At the outlet of the burner 103, there is a fuel injection hole 104 for injecting the premixed gas introduced into the premixed gas introduction space 102 into the combustion region 107. The burner 103 includes an ignition device 106 that ignites the premixed gas ejected from the fuel ejection holes 104. In addition, the ignition device 106 is composed of, for example, an igniter. The flame 105 is formed on the downstream side of the fuel ejection hole 104 as shown in FIG.

  The operation panel 150 includes, for example, an operation switch 151 for instructing start / stop of operation, an output setting switch 152 for setting the output of the combustor 100, and the like. The configuration of the operation panel 150 is not limited to these, and a monitor and various setting switches can be provided as needed.

  The control unit 90 illustrated in FIG. 1 mainly includes, for example, an arithmetic unit (CPU), storage means such as a read-only memory (ROM) and a random access memory (RAM), and input / output means. The CPU executes various arithmetic processes using, for example, a program or a database stored in the storage unit.

  The input / output unit inputs an electric signal from an external device or outputs an electric signal to the external device. Specifically, the input / output means is connected to, for example, the fan 20, the shutoff valves 42 and 43, the fuel flow meter 44, the pressure sensor 52, the operation panel 150, and the like so that various signals can be input and output. In the fan 20, the input / output means is connected to, for example, a motor for controlling the rotation speed of the fan 20, a fan tachometer 26 for detecting the rotation speed of the fan 20, and the like so that signals can be input and output.

  The input / output unit is connected to each device of the combustor 100 so that various signals can be input and output. The processing executed by the control unit 90 is realized by, for example, a computer device such as a microcomputer.

  The storage means includes, for example, a database of a set fuel flow rate corresponding to the rotation speed of the fan 20, a database of a fan rotation speed corresponding to the set output of the combustor 100, and a reference pressure in the cylinder 50 corresponding to the fan rotation speed. A database and the like are stored. The storage unit stores, for example, various databases for controlling the combustor 100. The database stored in the storage means is not limited to these, and other databases can be stored as needed.

  The control unit 90 controls the shutoff valves 42 and 43 based on output signals from the fan speed meter 26 and the fuel flow meter 44, for example. In addition, the control unit 90 controls the shutoff valves 42 and 43 based on output signals from the fan tachometer 26 and the pressure sensor 52, for example. Further, the control unit 90 controls, for example, the fan 20 based on the information input on the operation panel 150. Further, the control unit 90 controls each device of the combustor 100, each device of the air-fuel mixture supply device 10, and the like based on output signals from each device of the combustor 100, for example.

  The control in the control unit 90 is not limited to these. The control unit 90 can control the entire operation of the air-fuel mixture supply device 10 and the combustor 100, for example.

  Next, the operation of the air-fuel mixture supply device 10 and the combustor 100 will be described.

  When determining that the operation switch 151 for instructing start / stop of the operation of the operation panel 150 shown in FIG. 1 has been pressed, the control unit 90 activates the fan 20.

  Subsequently, the control unit 90 activates the ignition device 106 of the combustor 100. Then, the control unit 90 opens the shutoff valves 42 and 43 and supplies the fuel to the mixer 30.

  Specifically, when the fan 20 operates, the outside air passes through the flow straightening plate 51 and is sucked into the cylindrical body 50. The inside of the cylinder 50 has a negative pressure. The sucked air is guided to the mixer 30.

  In addition, when the shut-off valves 42 and 43 are opened, fuel is introduced from the fuel supply source 41 into the mixer 30 through the fuel supply pipe 40. When the fuel passes through the fuel supply pipe 40, the flow rate is adjusted by the fuel flow rate adjusting unit 70, and the flow rate is measured by the fuel flow meter 44. In the fuel flow rate adjusting unit 70, the flow rate is adjusted using the total pressure P3 in the cylinder 50 transmitted via the probe 61 and the transmission pipe 62 as a signal pressure.

  The air and the fuel introduced into the mixer 30 are mixed when passing through the passage 31 in the mixer 30, and become a premixed air having a predetermined air ratio, in other words, a predetermined equivalence ratio. This air-fuel mixture flows into the fan 20 from the suction port 24, is further mixed, and is introduced into the premixed air introduction space 102 of the combustor 100.

  The premixed gas introduced into the premixed gas introduction space 102 passes through the burner 103 and is ejected from the fuel ejection holes 104 to the combustion region 107. The premixed gas jetted to the combustion region 107 is ignited by an ignition device 106 and burns to form a flame 105.

  After igniting the burner 103, the control unit 90 refers to the fan rotation speed corresponding to the set output stored in the storage unit so that the output is set by the output setting switch 152 of the operation panel 150, for example, For example, based on the output from the fan tachometer 26, the motor 23 of the fan 20 is controlled to adjust the number of rotations of the fan 20. The air flow rate is adjusted by adjusting the rotation speed of the fan 20. Then, with the adjustment of the air flow rate, the fuel flow rate adjustment unit 70 adjusts the fuel flow rate.

  Here, for example, when the control unit 90 determines that the set output has been increased by the output setting switch 152 of the operation panel 150, the control unit 90 increases the rotation speed of the fan 20. Specifically, based on a signal related to the increased setting output from operation panel 150, control unit 90 refers to a database of the fan rotation speed corresponding to the setting output stored in the storage unit. Then, the control unit 90 controls the motor 23 of the fan 20 based on the fan rotation speed corresponding to the referred setting output and the output from the fan tachometer 26 to determine the rotation speed of the fan 20 in the fan rotation speed database. Adjust to a number.

  As the rotation speed of the fan 20 increases, the total pressure P3, which is the signal pressure, fluctuates more toward the negative pressure side. That is, as the rotation speed of the fan 20 increases, the absolute value of the total pressure P3 as the negative pressure increases. As a result, the diaphragm 75 shown in FIG. 3 is pulled toward the signal pressure chamber 80 (downward in FIG. 3), and the valve body 74 moves downward. Then, the outlet pressure P2 is adjusted so as to be the total pressure P3 whose pressure has changed to the negative pressure side. Thereby, the flow rate of the fuel introduced into the mixer 30 increases. The fuel flow rate is increased in accordance with the increase in the air flow rate so that a predetermined equivalence ratio can be maintained.

  On the other hand, for example, when the control unit 90 determines that the set output has been reduced by the output setting switch 152 of the operation panel 150, the control unit 90 decreases the rotation speed of the fan 20. Specifically, based on a signal related to the reduced setting output from operation panel 150, control unit 90 refers to a database of the fan rotation speed corresponding to the setting output stored in the storage unit. Then, the control unit 90 controls the motor 23 of the fan 20 based on the fan rotation speed corresponding to the referred setting output and the output from the fan tachometer 26 to determine the rotation speed of the fan 20 in the fan rotation speed database. Adjust to a number.

  As the rotation speed of the fan 20 decreases, the total pressure P3, which is the signal pressure of the negative pressure, changes to the atmospheric pressure side. That is, as the rotation speed of the fan 20 decreases, the absolute value of the total pressure P3, which is the negative pressure, decreases. Accordingly, the diaphragm 75 shown in FIG. 3 is pushed toward the secondary pressure communication chamber 81 (the upper side in FIG. 3), and the valve body 74 moves upward. Then, the outlet pressure P2 is adjusted so as to be the total pressure P3 whose pressure has changed to the atmospheric pressure side. Thereby, the flow rate of the fuel introduced into the mixer 30 decreases. In addition, the fuel flow rate is reduced in accordance with the decrease amount of the air flow rate so that a predetermined equivalent ratio can be maintained.

  As described above, in the air-fuel mixture supply device 10, the fuel pressure adjusting unit 70 uses the total pressure P <b> 3 of the cylinder 50 as the signal pressure, varies the fuel flow according to the variation in the air flow, and supplies the fuel to the combustor 100. The equivalence ratio, which is the mixture ratio of fuel and air, is kept constant.

  In addition, the air ratio in the air-fuel mixture supplied to the combustor 100 is set to, for example, about 1.30 to 1.60. That is, this mixture is a lean premix having an equivalent ratio of about 0.63 to 0.77.

  That is, when the air flow increases, the fuel flow adjuster 70 increases the fuel flow according to the increase in the air flow (increase in the absolute value of the total pressure P <b> 3, which is a negative pressure), and supplies the fuel to the combustor 100. The mixture ratio of fuel and air is kept constant. When the air flow rate is reduced, the fuel flow rate is reduced in the fuel flow rate adjusting unit 70 in accordance with the decrease in the air flow rate (decrease in the absolute value of the total pressure P3 as the negative pressure), and the fuel flow rate is supplied to the combustor 100. The mixture ratio of fuel and air, that is, the equivalence ratio is kept constant.

  In the combustor 100 to which the premixed air is supplied from the air / fuel mixture supply device 10, the premixed air having a constant equivalence ratio is supplied even when the output load in which the air flow rate changes is changed. Thus, in the combustor 100, stable combustion can be maintained over each output load, and nitrogen oxides (NOx) and the like can be suppressed.

  The operation of the air-fuel mixture supply device 10 and the combustor 100 described above is an example, and is not limited to the above-described operation. In the air-fuel mixture supply device 10, the full pressure of the cylinder 50 may be used as the signal pressure in the fuel flow rate adjusting unit 70.

  Here, the abnormality detection processing of the air-fuel mixture supply device 10 will be described.

  FIG. 4 is a diagram illustrating an example of a database of a set fuel flow rate corresponding to a fan rotation speed of the air-fuel mixture supply device 10 according to the embodiment. FIG. 5 is a flowchart of an abnormality detection process in the air-fuel mixture supply device 10 according to the embodiment.

  The storage unit of the control unit 90 stores, for example, a database of the set fuel flow rate corresponding to the fan speed as shown in FIG. In FIG. 4, the horizontal axis indicates the fan rotation speed, and the vertical axis indicates the set fuel flow rate. FIG. 4 specifically shows an appropriate range W1, a warning range W2, and an abnormal range W3, which will be described later, with respect to the predetermined fan speed, but these ranges are also defined for other fan speeds. Is the same.

  As shown in FIG. 4, the reference fuel flow rate corresponding to the fan speed is set, for example, on line L1. The range surrounded by the line L2 is set as an appropriate range (appropriate range W1) of the actual fuel flow rate (actual fuel flow rate) corresponding to the fan speed. Note that the appropriate range W1 includes a range on the line L2. That is, even if the actual fuel flow rate fluctuates to the increasing side or the decreasing side within a predetermined range from the reference fuel flow rate, the appropriate fuel flow rate range is set.

  Further, the range that exceeds the appropriate range W1 and is surrounded by the line L3 is not the range in which the actual fuel flow rate corresponding to the fan rotation speed is immediately determined to be the flow rate abnormality and the operation is stopped, but the possibility of causing the flow rate abnormality is high. It is set as a high range (warning range W2). Note that the warning range W2 includes a range on the line L3. In other words, the warning range W2 is a range between the line L2 and the line L3.

  Further, a range exceeding the warning range W2 is set as a range in which the actual fuel flow rate corresponding to the fan speed is determined to be abnormal and the operation is stopped (abnormal range W3). The range beyond the warning range W2 is the side on which the set fuel flow rate is larger or smaller than the line L3.

  Here, as a case where the actual fuel flow rate corresponding to the fan rotation speed becomes smaller than the set fuel flow rate stored in the database, there is a case where an appropriate air flow rate corresponding to the fan rotation speed is not flowing.

  A cause of this case is, for example, clogging of the current plate 51. That is, when the flow straightening plate 51 is clogged, air having a flow rate smaller than an appropriate flow rate corresponding to the fan rotation speed flows. In the fuel flow rate adjusting section 70, the fuel flow rate is adjusted in accordance with the air flow rate that is actually flowing. Therefore, when the air flow rate decreases, the actual fuel flow rate also decreases.

  Examples of the case where the fuel flow rate becomes larger than the set fuel flow rate stored in the database with respect to the fan rotation speed include a case where the signal pressure is not transmitted to the signal pressure chamber 80, that is, a case where the signal pressure is not applied to the signal pressure chamber 80. No.

  The cause in this case is, for example, a case where the probe 61 is damaged and communicates with the atmosphere.

  Next, the abnormality detection processing of the air-fuel mixture supply device 10 will be described with reference to the flowchart shown in FIG.

  The control unit 90 refers to the set fuel flow rate corresponding to the fan speed stored in the database, and determines the actual fuel flow rate with respect to the fan speed based on the outputs from the fan speed meter 26 and the fuel flow meter 44. It is determined whether it is within the appropriate range W1 (step S200).

  Specifically, the control unit 90 specifies the actual fan speed based on the output from the fan speed meter 26, and specifies the set fuel flow rate at the actual fan speed from the database. Subsequently, the control unit 90 specifies the actual fuel flow rate based on the output from the fuel flow meter 44, compares the actual fuel flow rate with the set fuel flow rate specified from the database, and determines the actual fuel flow rate at the actual fan speed. It is determined whether or not the range is within the appropriate range W1.

  If it is determined in step S200 that the actual fuel flow rate is within the appropriate range W1 with respect to the fan rotation speed (Yes in step S200), the control unit 90 executes the processing in step S200 again.

  If it is determined in step S200 that the actual fuel flow rate is not within the appropriate range W1 with respect to the fan rotation speed (No in step S200), the control unit 90 sets the set fuel corresponding to the fan rotation speed stored in the database. Referring to the flow rate, it is determined whether or not the actual fuel flow rate is within the warning range W2 with respect to the fan speed based on the outputs from the fan speed meter 26 and the fuel flow meter 44 (step S202).

  Specifically, the control unit 90 specifies the actual fan speed based on the output from the fan speed meter 26, and specifies the set fuel flow rate at the actual fan speed from the database. Subsequently, the control unit 90 specifies the actual fuel flow rate based on the output from the fuel flow meter 44, compares the actual fuel flow rate with the set fuel flow rate specified from the database, and determines the actual fuel flow rate at the actual fan speed. It is determined whether the range is within the warning range W2.

  When it is determined in step S202 that the actual fuel flow rate is within the warning range W2 with respect to the fan speed (Yes in step S202), the control unit 90 executes a warning issuance process (step S204). .

  In the warning issuance process, for example, when the operation panel 150 has a display unit such as a monitor, the control unit 90 displays the warning information on the display unit. When the operation panel 150 has a warning lamp, the control unit 90 turns on or blinks the warning lamp. Further, when the operation panel 150 has a sound source function of emitting a sound, the control unit 90 activates the sound source function to sound a warning sound.

  If the actual fuel flow rate is lower than the set fuel flow rate stored in the database with respect to the fan rotation speed in the warning issuance process, the control unit 90 causes the rectifier plate 51 to become clogged, for example. The display indicating that the user is present may be displayed on the display unit. Further, the operation panel 150 may be provided with a warning lamp or a sound source function indicating that the current plate 51 is clogged.

  If it is determined in step S202 that the actual fuel flow rate is not within the warning range W2 with respect to the fan speed (No in step S202), the control unit 90 executes an operation stop process (step S206).

  In the determination in step S202, the case where the actual fuel flow rate is not within the warning range W2 with respect to the fan speed is the case where the actual fuel flow rate is not within the appropriate range W1 and the warning range W2, that is, corresponds to the above-described abnormal range W3.

  In the operation stop processing, the control unit 90 closes the shutoff valves 42 and 43, and shuts off the supply of the fuel to the mixer 30, for example. In this case, for example, when the operation panel 150 has a display unit such as a monitor, the control unit 90 may display the abnormality detection information on the display unit. Further, when there is an abnormal lamp on operation panel 150, control unit 90 may light or blink the abnormal lamp. Further, when the operation panel 150 is provided with a sound source function of emitting a sound, the control unit 90 may activate the sound source function to emit a sound.

  As described above, by providing the abnormality detection processing function, an abnormality in the air-fuel mixture supply device 10 can be reliably detected. In addition, by providing the abnormality detection processing function, the safety of the air-fuel mixture supply device 10 can be improved. Further, by providing the abnormality detection processing function, the user can confirm the operation state of the air-fuel mixture supply device 10, and can recognize, for example, the maintenance time of the rectifying plate 51 and the like.

  Here, the abnormality detection processing of the air-fuel mixture supply device 10 is not limited to the above-described processing. In the air-fuel mixture supply device 10, an abnormality may be detected as follows.

  The control unit 90 detects the actual pressure (static pressure) in the cylinder 50 based on the output signal from the pressure sensor 52. Then, based on the reference pressure in the cylinder 50 corresponding to the fan rotation speed stored in the database, the control unit 90 determines that the actual pressure exceeds, for example, ± 20% of the reference pressure with respect to the fan rotation speed. If it is determined that there is an error, it is determined that it is within the abnormal range.

  When the control unit 90 determines that the actual pressure is in the abnormal range with respect to the fan rotation speed based on the reference pressure in the cylinder 50 corresponding to the fan rotation speed stored in the database, Execute operation stop processing. This operation stop processing is the same as the processing in step S206 described above.

  In the air-fuel mixture supply device 10, by providing the abnormality detection processing based on the actual pressure in the cylindrical body 50 in addition to the abnormality detection processing shown in FIG. 5, a double abnormality detection function is provided. Thereby, the safety of the air-fuel mixture supply device 10 can be further improved.

  Next, a pressure change in the cylinder 50 of the air-fuel mixture supply device 10 with respect to the output load of the combustor 100 will be described.

  FIG. 6 is a diagram illustrating changes in total pressure, static pressure, and dynamic pressure in the cylinder 50 of the air-fuel mixture supply device 10 with respect to the output load of the combustor 100. The horizontal axis in FIG. 6 indicates the output load of the combustor 100, and the vertical axis indicates the pressure. In FIG. 6, a pressure equal to or greater than 0 is defined as a positive pressure, and a pressure smaller than 0 is defined as a negative pressure. The pressure is a gauge pressure.

  As shown in FIG. 6, the static pressure decreases as the output load of the combustor 100 increases. That is, since the static pressure shown in FIG. 6 is a negative pressure, its absolute value increases as the output load of the combustor 100 increases.

  Like the static pressure, the total pressure decreases as the output load of the combustor 100 increases. However, since the dynamic pressure is a positive pressure and the dynamic pressure increases with an increase in the output load of the combustor 100, a decrease in the total pressure (an increase in the absolute value of the total pressure) corresponds to a decrease in the static pressure (an increase in the static pressure). Increase in absolute value of pressure).

  Then, as shown in FIG. 6, as the output load of the combustor 100 increases, the pressure difference between the total pressure and the static pressure increases.

  That is, the use of the total pressure in the cylinder 50 as a negative pressure as the signal pressure in the fuel flow rate adjusting unit 70 is more appropriate than the use of the static pressure in the cylinder 50 as the negative pressure. Can be supplied.

  Here, as described above, in a conventional air-fuel mixture supply device including a negative pressure type mixing chamber and using a static pressure as a signal pressure of the equalizing valve, the equalizing valve is designed to ensure a fuel flow rate at a low output load. It is adjusted by the adjustment mechanism. Therefore, at the time of high output load, more fuel flow than the proper fuel flow is discharged from the equalizing valve.

  However, as in the air-fuel mixture supply device 10 of the present embodiment, the output pressure of the combustor 100 is increased by using the total pressure in the cylinder 50 that is a negative pressure as the signal pressure of the fuel flow rate adjusting unit 70. , The increase of the signal pressure accompanying this is suppressed. Thereby, even when the output load of the combustor 100 increases, an appropriate fuel flow rate can be supplied.

  As described above, according to the air-fuel mixture supply device 10 of the present embodiment, the total pressure in the cylinder 50 that is a negative pressure is used as the signal pressure of the fuel flow rate adjustment unit 70, so that the low-pressure load Even if the fuel flow rate adjusting unit 70 is adjusted to secure the fuel flow rate, an appropriate fuel flow rate can be supplied even under a high output load. Therefore, the air-fuel mixture supply device 10 of the present embodiment can supply a pre-air-fuel mixture in which the mixing ratio of fuel and air, that is, the equivalence ratio, is kept constant from a low output load to a high output load. .

  Although several embodiments of the present invention have been described, these embodiments are provided by way of example and are not intended to limit the scope of the invention. These new embodiments can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and their equivalents.

  DESCRIPTION OF SYMBOLS 1 ... Combustion apparatus, 10 ... Air-fuel mixture supply apparatus, 20 ... Fan, 21, 79, 101 ... Casing, 22 ... Rotating blade, 23 ... Motor, 24 ... Suction port, 25 ... Discharge port, 26 ... Fan tachometer, Reference Signs List 30 mixer, 31 passage, 32, 40a one end, 33 throat portion, 34 other end, 40 fuel supply pipe, 41 fuel supply source, 42, 43 shutoff valve, 44 fuel flow meter 50 ... Cylinder, 51 ... Rectifier plate, 52 ... Pressure sensor, 60 ... Total pressure detecting unit, 61 ... Probe, 62 ... Transmission pipe, 63 ... Total pressure detecting port, 70 ... Fuel flow rate adjusting unit, 71 ... Fuel inlet , 72 ... fuel outlet, 73 ... signal pressure inlet, 74 ... valve body, 75 ... diaphragm, 76 ... spring, 77 ... adjustment mechanism, 78 ... valve stem, 80 ... signal pressure chamber, 81 ... secondary pressure communication chamber , 82: secondary pressure communication path, 83: partition membrane, 90: control unit, 10 ... combustor, 102 ... premixed gas introduction space, 103 ... burner, 104 ... fuel outlet, 105 ... flame, 106 ... ignition device, 107 ... combustion area, 150 ... operation panel, 151 ... operation switch, 152 ... output setting Switch, P1: inlet pressure, P2: outlet pressure, P3: total pressure.

Claims (9)

An air-fuel mixture supply device for supplying a pre-mixture of fuel and air to a combustor,
A fan for blowing the premixed air to the combustor,
A mixer having one end connected to the suction port of the fan and mixing fuel and air;
A fuel supply pipe connected to the mixer to supply fuel into the mixer;
A cylindrical body connected to the other end of the mixer and having a negative pressure inside due to a suction force caused by air blowing from the fan;
A rectifying unit that is provided at an opening end of the cylinder and rectifies air introduced into the cylinder,
A total pressure detection unit that detects a total pressure of air sucked into the cylinder via the rectification unit,
A fuel flow rate adjuster interposed in the fuel supply pipe and adjusting the fuel supplied at the primary pressure to a secondary pressure based on the total pressure detected by the total pressure detector and discharging the fuel to the mixer side; An air-fuel mixture supply device comprising: The passage in the mixer includes a venturi structure having a throat portion in which a passage cross-sectional area gradually decreases in a flow direction,
The air-fuel mixture supply device according to claim 1, wherein an outlet of the fuel supply pipe communicates with the inside of the throat portion.   3. The air-fuel mixture supply device according to claim 1, wherein the fuel flow rate adjusting unit is configured by a pressure equalizing valve or a zero governor.   The air-fuel mixture supply device according to any one of claims 1 to 3, wherein the total pressure detection unit includes a tubular probe having a total pressure detection port facing a flow direction of air. A rotation speed detection unit that detects a fan rotation speed of the fan,
A fuel flow rate detection unit that detects a flow rate of the fuel flowing through the fuel supply pipe,
An operation state is detected based on a fan speed detected by the speed detecting unit, an actual fuel flow detected by the fuel flow detecting unit, and a set fuel flow corresponding to the fan speed stored in the database. The air-fuel mixture supply device according to any one of claims 1 to 4, further comprising a control unit.   The control unit, based on the set fuel flow rate corresponding to the fan speed stored in the database, determines that the actual fuel flow rate is in a warning range that is likely to cause a flow rate abnormality, and issues a warning notification process. 6. The air-fuel mixture supply device according to claim 5, wherein: A shutoff valve interposed in the fuel supply pipe, for shutting off fuel flowing through the fuel supply pipe,
The control unit, when determining that the actual fuel flow rate is in an abnormal range based on a set fuel flow rate corresponding to a fan rotation speed stored in a database, closes the shutoff valve. 7. An air-fuel mixture supply device according to 5 or 6. A pressure detection unit that detects the pressure of the cylindrical body,
The control unit, based on the reference pressure in the cylinder corresponding to the fan rotation speed stored in the database, based on the actual pressure detected by the pressure detection unit, when it is determined that the abnormal range, the shut-off valve The mixture supply device according to any one of claims 5 to 7, wherein the device is closed. An air-fuel mixture supply device according to any one of claims 1 to 8,
A combustor for combusting a pre-mixture of fuel and air supplied from the mixture supply device.

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