JP5981239B2 - Flame detector - Google Patents

Description

  Embodiments described herein relate generally to a flame detection device.

  In boiler facilities installed in thermal power plants and private power plants, it is important to manage the presence and state of flames to prevent accidents. In a boiler, ignition of the burner may fail (non-ignition) or the burner may extinguish (fire extinction). In such a case, the fuel supply must be stopped immediately. If fuel supply is continued without detecting non-ignition or fire extinction, the fuel in the boiler becomes excessive, causing an explosion or cracking the boiler. The damage of such an accident is extremely large, and a flame detection device for detecting the presence or state of a flame is conventionally used to prevent the accident.

  The flame detection device detects the presence or state of a flame by detecting ultraviolet rays or infrared rays emitted from the flame of the burner, and is for detecting non-ignition, extinction, and unstable combustion.

Japanese Examined Patent Publication No. 62-41329 JP 2011-95083 A JP 2004-69186 A

  Since the boiler controls the fuel supply and stop of the burner based on the signal output from the flame detection device, if the flame detection device has a false detection, the function of the boiler cannot be performed sufficiently. Causes of false detection include improper setting of zero output and the influence of flames of other burners in the boiler.

  The zero output is set by adjusting the output level when the flame detection device covers the mouth for taking in ultraviolet rays and infrared rays so that ultraviolet rays and infrared rays are not detected. However, the conventional flame detection device is not completely covered due to the structure considering durability, etc., and ultraviolet rays and infrared rays enter through the gaps, and the light cannot be completely zeroed, or the cover is attached / detached. The structure is complicated and not strong, and the cover may not be able to be attached or detached due to a failure, and it is difficult to set the zero output appropriately.

  In addition, since the boiler is provided with a plurality of burners, there are inconveniences such as detecting the flame of a neighboring burner even though the burner to be detected is extinguished. There is still no way to prevent it properly.

The flame detection apparatus according to the embodiment includes a sensor, a cylinder, a lid, an opening / closing mechanism unit, and an activation unit . A sensor detects the light which a flame emits and notifies the presence or absence of a flame. A cylinder has an opening which goes to the crater of the burner which incorporates a sensor and ejects the flame used as the detection object of the sensor concerned. The lid is rotatably mounted in the vicinity of the opening, and is movable between a closed position where the lid is in close contact with the opening and the opening is separated from the opening. The opening / closing mechanism moves the lid between the closed position and the open position when adjusting the output of the sensor. The activating part generates power for moving the lid. The opening / closing mechanism includes a shaft that is slidably supported by the cylinder in the longitudinal direction of the cylinder, a cylinder that applies a force that slides on the axis by the power generated by the generator, and a stopper that restricts the sliding of the axis to a predetermined range. And a lever fixedly provided on the lid, and provided to be freely adjustable in position by a shaft that slides by stopping the operation of the generator, and engages with the lever to rotate the lid toward the open position. The opening engaging part that adjusts the pivot position when the lid is opened and the shaft that slides by operating the triggering part are adjustable, and the lever is engaged to rotate the lid toward the closed position. And a closing engagement portion that adjusts the rotation position when the lid is closed.

FIG. 1 is a schematic diagram of a boiler in which the flame detection device of the first embodiment is installed and a thermal power generation facility using the boiler. FIG. 2 is a cross-sectional view showing the structure of the flame detection device of the first embodiment, in which the shielding plate is in the closed position. FIG. 3 is a cross-sectional view showing the structure of the flame detection device of the first embodiment, in which the shielding plate is in the open position. FIG. 4 is a partial cross-sectional view illustrating the structure of the opening / closing mechanism unit of the first embodiment. FIG. 5 is a schematic diagram for explaining the difference in the field of view of the sensor due to the difference in the opening degree of the shielding plate located at the open position in the first embodiment. FIG. 6 is a schematic diagram for schematically explaining how to change the visual field of the sensor according to the second embodiment.

(First embodiment)
Hereinafter, an embodiment of a flame detection device will be described with reference to the accompanying drawings. Moreover, in this embodiment, the case where it installs and uses for the boiler used at a thermal power plant etc. is demonstrated to an example. FIG. 1 is a schematic diagram of a boiler in which the flame detection device of the present embodiment is installed and a thermal power generation facility using the boiler. The thermal power generation facility includes a boiler 1, a turbine 2, and a generator 3. The turbine 2 is rotated by the power of steam generated in the boiler 1, and the generator 3 to which the rotation of the turbine 2 is transmitted generates power. .

The boiler 1 includes a water tube 4, a burner 5, a flame detection device 6, and a protective tube 7.
The water pipe 4 meanders in the boiler 1, one end is connected to a water supply facility (not shown), and the other end is connected to the turbine 2. A plurality of burners 5 are provided in the boiler 1 to heat the water in the water pipe 4. The flame detection device 6 detects the flame of the burner 5. The protective tube 7 is provided through the outer wall 1a of the boiler 1, and covers the outer periphery of the flame detection device 6 to protect it from the flame.

2 and 3 are cross-sectional views showing the structure of the flame detection device 6. The flame detection device 6 includes a sensor 11, a cap 12 as a cylinder, a glass plate 13, a hood 14, a shielding plate 15 as a lid, an opening / closing mechanism portion 16, and an air compressor (not shown) as an activation portion. It has. Here, FIG. 2 shows a state where the shielding plate 15 is in a closed position (described later), and FIG. 3 shows a state where the shielding plate 15 is in an open position (described later).
The sensor 11 detects the ultraviolet rays emitted from the flame of the burner 5 and outputs a signal notifying the presence or absence of the flame.

  The cap 12 incorporates the sensor 11 and has a cylindrical portion 121 and a flange portion 122. The cylinder part 121 covers the outer periphery of the sensor 11. The flange portion 122 is fixed to the cylindrical portion 121 and has an opening 12a (see FIG. 3) for taking in ultraviolet rays emitted from the flame of the burner 5.

The glass plate 13 protects the sensor 11, is positioned between the sensor 11 and the opening 12 a, and has an outer periphery fixed to the inner peripheral surface of the flange portion 122.
The hood 14 is the outermost shell at the tip of the flame detection device 6, covers the cap 12 and the opening / closing mechanism 16, and is fixed to the cylinder 121.

The shielding plate 15 is configured to be movable between a closed position shown in FIG. 2 and an open position shown in FIG. 3, and closes the opening 12a in close contact with the opening 12a of the cap 12 and closes the opening 12a in the open position. The opening 12a is opened away from the center. Further, the shielding plate 15 limits the field of view of the sensor 11 to a predetermined range (α) in the open position.
The opening / closing mechanism 16 moves the shielding plate 15 between the open position and the closed position.

  FIG. 4 is a partial cross-sectional view showing the structure of the opening / closing mechanism 16. As shown in FIG. 2, the opening / closing mechanism 16 includes a bracket 21, a lever 22, a switching shaft 23, an opening engagement piece 24, and a closing engagement piece 25. As shown in FIG. 4, the opening / closing mechanism section 16 includes an air cylinder 26, an air tube 27, an open slide stopper 28, and a closed slide stopper 29.

  The bracket 21 is a plate-like member fixed to the hood 14 and supports the lever 22 so as to be rotatable. The lever 22 is pivotally supported by the bracket 21 at the center, and a shielding plate 15 is attached to one end. The other end is an engagement end 22 a that engages with the opening engagement piece 24 and the closing engagement piece 25.

The switching shaft 23 is a thin metal shaft. The opening engagement piece 24 is fixed in the vicinity of the tip, and is closed at a position spaced apart from the opening engagement piece 24 away from the tip of the switching shaft 23. The hour engagement piece 25 is fixed.
The engaging end 22a of the lever 22 is located between the opening engaging piece 24 and the closing engaging piece 25, and moves with the sliding of the switching shaft 23. Engage with the frame 25. As a result, the lever 22 rotates as the switching shaft 23 slides.

The air cylinder 26 has a well-known structure, and is connected to an air compressor by an air tube 27. The air cylinder 26 slides the switching shaft 23 by using the pressure of compressed air obtained by operating the air compressor as power. .
Here, the air cylinder 26 is in a state in which the switching shaft 23 is most retracted in a power-off state where the air compressor is not operating. At this time, the engagement end 22a of the lever 22 engages with the engagement piece 24 at the time of opening, the lever 22 obtains the rotational force in the clockwise direction in FIGS. 2 and 3, and the shielding plate 15 is located at the open position. To do.

  The air cylinder 26, the open-time slide stopper 28, and the close-time slide stopper 29 are fixed to a member 14 a that is fixed to the hood 14. Further, the switching shaft 23 includes an engaging protrusion 23 a at a position close to the air cylinder 26. The open-time slide stopper 28 and the closed-time slide stopper 29 are arranged so as to sandwich the engaging protrusion 23a.

  When the air cylinder 26 retracts the switching shaft 23, the opening slide stopper 28 is engaged with the engaging protrusion 23 a and determines the opening position of the shielding plate 15. When the air cylinder 26 pushes out the switching shaft 23, the closing slide stopper 29 is engaged with the engaging protrusion 23 a and determines the closing position of the shielding plate 15.

  The opening engagement piece 24, the closing engagement piece 25, the opening slide stopper 28, and the closing slide stopper 29 are fixed by screws or the like so that the position can be adjusted in the field. ing. Then, by adjusting the position of the open slide stopper 28, the opening degree of the shielding plate 15 located at the open position is determined, and the field of view of the sensor 11 is determined.

  In such a configuration, the flame detection device 6 according to the present embodiment outputs a signal notifying the presence or absence of a flame by the sensor 11 detecting the ultraviolet rays emitted from the burner 5 and incident from the opening 12a of the cap 12. .

  When setting the zero output of the sensor 11, the air compressor is operated, the switching shaft 23 is pushed out by the air cylinder 26, and the lever 22 is rotated in the counterclockwise direction in FIGS. Is positioned at the closed position, and the opening 12a of the cap 12 is closed by the shielding plate 15. At this time, the shielding plate 15 comes into close contact with the opening 12 a of the cap 12, and a light zero state in which light does not enter the sensor 11 is achieved.

  FIG. 5 is a schematic diagram for explaining the difference in the field of view of the sensor 11 due to the difference in the opening degree of the shielding plate 15 located at the open position. For example, if the light emitted from the burner 5 'adjacent to the burner 5 to be detected by the sensor 11 is incident on the sensor 11 when the visual field is in the range indicated by α, The positions of the opening engagement piece 24 and the opening slide stopper 28 are adjusted so as to be narrowed to β that does not enter. This prevents erroneous detection of the sensor 11 due to the flame of the burner 5 '.

  Thus, according to the present embodiment, when adjusting the zero output, the shielding plate 15 can be brought into close contact with the opening 12a of the cap 12 so that the light is in the zero state, and the output from the sensor 11 can be easily obtained. Can be set to zero output.

  Further, according to the present embodiment, since the shielding plate 15 is located in the open position when the air compressor is not operating, the state of the air compressor is set during normal operation of the boiler 1 that does not set zero output. Regardless, the flame can be detected.

Furthermore, according to the present embodiment, since the field of view of the sensor 11 can be adjusted, erroneous detection due to the influence of the other burner 5 ′ in the boiler 1 can be reduced.
Furthermore, since the field of view of the sensor 11 can be adjusted by an easy method of changing the position of the open slide stopper 28, the difficulty at the work site can be greatly reduced.

In addition, according to the present embodiment, a simple structure in which the switching shaft 23 is slid to open and close the shielding plate 15 and a simple structure in which the shielding plate 15 is brought into close contact with the opening 12a to prevent light from entering. Therefore, it is difficult for problems due to deformation of the members to occur, and the cause of the problems can be reduced.
The weight of the member can be reduced by the simple structure, and the pressure of the air compressor for sliding the switching shaft 23 can be reduced.

(Second Embodiment)
Next, another embodiment for adjusting the field of view of the sensor 11 will be described. FIG. 6 is a schematic diagram for schematically explaining how to change the field of view of the sensor 11 in the present embodiment. In the present embodiment, the field of view of the sensor 11 is adjusted as shown in FIG. 6 by changing the flange portion 122 (see FIG. 3) of the cap 12 to one having a different diameter of the opening 12a (see FIG. 3).

According to the present embodiment, since the field of view of the sensor 11 can be adjusted over the entire circumference, it becomes easier to eliminate the influence of the burner 5 ′ that is not a detection target as compared with the first embodiment.
In the present embodiment, the shielding plate 15 may not necessarily be used to limit the field of view of the sensor 11, and the limitation of the field of view of the sensor 11 by the shielding plate 15 may be used as necessary.

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

  6 Flame detector, 11 Sensor, 12 Cap (cylinder), 15 Shield plate (lid), 16 Opening / closing mechanism

Claims (4)

A sensor that detects the light emitted by the flame and notifies the presence or absence of the flame;
A cylinder having an opening toward a crater of a burner that incorporates the sensor and ejects a flame to be detected by the sensor;
A lid that is rotatably mounted in the vicinity of the opening, and is movable between a closed position that closes the opening and closes the opening, and an open position that is spaced apart from the opening;
An opening / closing mechanism that moves the lid between the closed position and the open position when adjusting the output of the sensor;
An activating part for generating power for moving the lid;
Equipped with a,
The opening / closing mechanism is
A shaft that is slidably supported by the cylinder in the longitudinal direction of the cylinder;
A cylinder that applies a force to slide on the shaft by the power generated by the motor,
A stopper for restricting the slide of the shaft to a predetermined range;
A lever fixed to the lid;
The shaft is slidable by stopping the operation of the moving portion, and the lid is rotated toward the open position by engaging with the lever, and the rotation position when the cover is opened is set. An opening engaging portion to be adjusted;
The position is freely adjustable on the shaft that slides by operating the motor, and engages with the lever to rotate the lid toward the closed position and adjusts the rotational position when the lid is closed. A closing engagement portion to
A flame detector. 2. The flame detection device according to claim 1, wherein the opening / closing mechanism section defines a position where the lid limits a visual field of the sensor within a predetermined range and blocks light emitted by a flame not detected by the sensor as a release position. The flame detection device according to claim 1, wherein the opening of the cylinder has a diameter large enough to limit a field of view of the sensor to a predetermined range and block light emitted by a flame that is not a detection target of the sensor. The opening / closing mechanism section defines a position where the lid blocks a light emitted by a flame that is not a detection target of the sensor as the opening position, depending on a position of the stopper and a position of the opening engaging section. 4. The flame detection device according to any one of 3 above.

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