JP2667429B2 - Long pull-out type soot blower and its operating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a long-removal type soot blower (soot blower),
In particular, the present invention relates to a long-displacement type soot blower capable of suppressing a swing caused by resonance of an outer tube (lance tube) having a long insertion / removal distance and contributing to downsizing and safety of a boiler apparatus in which a soot blower is installed, and an operation method thereof.

[Conventional technology]

The outer tube of the long slip-type soot blower is supported by a roller bracket installed near the water-cooled furnace wall of the furnace and outside the furnace, and rotates and moves forward and backward while injecting high-pressure steam or compressed air as the injection medium. By the operation, the water-cooled furnace wall is inserted into the furnace in a cantilever shape for removing dust such as soot or clinker (slag) attached to the surface of the furnace wall tube constituting the water-cooled furnace wall. For example, if the outer diameter of the outer tube is
127mm can be more than 15m long and can be rotated, so the tip of the outer tube may swing during one rotation due to the initial bending (not straight) of the outer tube near the maximum insertion position in the furnace. , The natural frequency and the rotation speed of the outer tube at that time approach, and the outer tube vibrates greatly due to the resonance state. If only the initial deflection of the outer tube is affected, the outer tube simply rotates while drawing a certain substantially circular trajectory. However, when the above-described resonance state is reached, the outer tube undergoes abnormal and large swinging. For example, the center of the distal end of the outer tube is displaced by 150 mm or more, and the trajectory of rotation of the distal end does not have a circular shape, and draws an unspecified trajectory. The shock causes the tip to move in an unpredictable direction, so that the swing is large and the trajectory of rotation causes an extremely irregular and shocking movement. Therefore, when the tip of the outer tube of the soot blower is provided close to the furnace wall tube constituting the water-cooled furnace wall of the furnace, damage due to contact of the outer tube with the furnace wall tube and a serious accident may occur. Therefore, it is extremely dangerous to determine the gap (cavity space) between the furnace wall tubes only by considering the bending of the tip portion of the outer tube. Also, even if the time required for reverse rotation at the time of maximum insertion of the outer tube is stopped for about 1 second, the swing of the outer tube at the time of forward movement does not stop by itself,
If reverse rotation occurs in this state, an abnormal swing will occur due to the reaction, and this is not a solution for preventing the outer tube from swinging. In the prior art, no consideration was given to suppressing and preventing the swing of the outer tube of the long-removal type soot blower.

[Problems to be solved by the invention]

As described above, in the related art, irregular swinging due to resonance of the outer tube of the long-removal type soot blower is large, and there is a risk of causing an accident by contacting the furnace wall tube constituting the water-cooled furnace wall of the furnace. There was a problem of lack of safety. Further, due to the above-mentioned irregular large swing, the gap (cavity space) of the furnace wall tube for inserting the outer tube of the soot blower into the furnace cannot be reduced, so that the boiler device cannot be downsized. However, no consideration has been given to suppressing and preventing the swing of the outer tube of the long-removal type soot blower.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art, minimize the swing of the outer tube of the long-drawing soot blower, and reduce the cavity space of a furnace wall tube such as a boiler. It is an object of the present invention to provide a highly reliable and highly reliable long-removal type soot blower which can be made compact and which does not cause abnormal shaking, and a method of exercising the same.

[Means for solving the problem]

The object of the present invention is to elongate the natural frequency of the outer tube of the difference type soot blower, the rotation speed of the outer tube,
Keep the outer tube as far as possible from the resonance area near the maximum insertion position of the outer tube, and when the specified distance from the maximum insertion position of the outer tube is approached, reduce the rotation speed of the outer tube from the set rotation speed to the low-speed side by inverter control. This is achieved by controlling.

In the long pull-out soot blower of the present invention, it is only necessary to add a limit switch for inverter control at a position at a specific distance from a position in front of the reverse rotation limit switch provided at the foremost portion in the forward direction of the outer tube. The object of the present invention can be achieved, and the main body of the long plug-in soot blower does not need to be changed at all.

In the long pull-out type soot blower of the present invention, when the outer tube is advanced and the specific insertion distance is approached to the maximum insertion position, the set rotation speed of the outer tube is gradually reduced by the inverter control, and the maximum insertion of the outer tube is performed. After reversing the rotation near the position, while rotating the outer tube backward, gradually increase the rotation speed again and return to the original rotation speed at a specific distance from the maximum insertion position of the outer tube. As a result, it is possible to prevent shaking due to resonance that occurs at the outer tube tip portion. In addition, the inverter control is provided with a rotation speed setting device and a function that can set the time from zero rotation speed to the set rotation speed and from the set rotation speed to the rotation speed zero to prevent overload. I have.

Inverter control in the long-removal type soot blower of the present invention is to control the set insertion position of the outer tube, which is a specific distance away from the maximum insertion position of the outer tube, to a set arbitrary rotation speed and an arbitrary stroke speed. Can be. For example, about the maximum insertion position of the outer tube
Increase the stroke speed of the outer tube to the position of 1.5 m,
When the set insertion position of the outer tube is reached (for example,
By setting the sensor to a low rotation speed by an electric signal to the rotation speed setting device of the inverter control,
In the section where the outer tube swing is small, the stroke (forward or reverse) speed is increased, and the stroke speed is reduced from the set insertion position of the outer tube where the swing increases to the vicinity of the maximum insertion position, thereby reducing the outer tube swing. It can be minimized.

The set rotation speed of the outer tube of the long-removable soot blower of the present invention can be made variable. For example, the rotation speed of the outer tube is 25 rpm, the stroke speed is 2.5 m / min, the rotation speed is reduced at a point 1.5 m before the maximum insertion position, and the rotation speed is 20 rpm,
By setting the stroke speed to 2 m / min, the swing of the outer tube can be reduced by about 50%. The change in the set rotation speed of the outer tube depends on the maximum insertion length of the outer tube into the furnace, the positional relationship between the furnace wall tube and the soot blower, and the type of dust (soot, clinker, etc.) It is set according to the state of adhesion.

[Action]

When the motor is started through the inverter, the rotation of the motor does not immediately reach the synchronous speed, and the rotation speed gradually increases. Conversely, when the inverter is turned off, the rotational speed of the motor gradually decreases. By the performance of this inverter, the outer tube is advanced, and when the maximum insertion position is near a specific distance, by turning off the inverter, the rotation speed of the outer tube gradually decreases,
Also, when the motor is reversed near the maximum insertion position of the outer tube and the outer tube is moved backward, the rotation speed of the outer tube gradually increases, and when a certain distance from the maximum insertion position of the outer tube is reached, the outer tube is set to the set position. Return to speed. By this operation, it is possible to reduce the number of revolutions in a section where resonance is likely to occur near the maximum insertion position where the vibration of the outer tube becomes large, so that the vibration due to the resonance of the outer tube can be extremely reduced. And
Although the cleaning effect is improved by lowering the rotation speed of the outer tube, the function of the soot blower is not reduced at all.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in more detail with reference to the drawings.

FIG. 1 shows an example of the long pull-out type soot blower of the present invention. In the drawing, the trolley 2 has an outer tube 4 and an inner tube 3 that can rotate and move forward and backward. The outer tube 4 is close to a furnace wall tube 6 of a water-cooled furnace wall.
Moreover, it is supported by a roller bracket 5 provided outside the furnace. An injection medium 11 composed of high-pressure steam or compressed air is introduced from the main valve 1 into the inner tube 3 and injected into the furnace from the injection holes 7 to perform rotation, forward and backward operations, thereby performing the water-cooled furnace of the furnace. The cleaning is performed by removing soot or clinker (slag) attached to the surface of the furnace wall tube 6 constituting the wall.

The feature of the long-removal type soot blower of the present invention is that the forward end of the soot blower is provided with a limit switch 9 for reverse rotation of the outer tube and a limit switch 10 for inverter control in front of the limit switch 9 for reverse rotation. The point is to freely control the number of rotations and prevent the vibration due to its resonance.

When operating a conventional long pull-out type soot blower,
As shown in FIG. 3, the relationship between the length of insertion of the outer tube into the furnace and the natural frequency of the outer tube, as shown in FIG. 3, becomes closer to the maximum insertion point (c) of the outer tube. ) And the rotation speed (b) of the outer tube approach each other and approach the maximum point of resonance.
Therefore, in the long-removal type soot blower of the present invention, as shown in FIG.
It is reduced before approaching the resonance state, so as not to approach the natural frequency (a) of the outer tube, and it is possible to prevent the outer tube from swinging due to resonance. That is,
As shown in FIG. 1, near the maximum insertion position of the outer tube 4, the inverter control limit switch 10 provided about 1 m to 1.5 m before the reverse rotation limit switch 9 for reversing the outer tube 4 is turned off. By operating, the inverter is turned off and the rotation of the motor gradually decreases. By gradually moving the outer tube to the maximum insertion position in the furnace while gradually reducing the rotation and forward speed of the outer tube, the outer tube is operated by operating the reverse rotation limit switch 9 provided at the foremost portion of the soot blower. The forward rotation and rotation of the outer tube 4 are stopped, the inverter for reverse rotation of the motor is turned on, and the outer tube 4 is moved backward while gradually increasing the reverse rotation.
When the outer tube retracts to the home position, the motor and the inverter are turned off by the stop limit switch 8, and one operation of the soot blower is completed. As described above, by turning the inverter off or on near the maximum insertion position of the outer tube in the furnace, the rotation speed and the forward / reverse speed of the outer tube are reduced as the position approaches the maximum insertion position, thereby causing the outer tube to swing. Can be effectively suppressed. Therefore, the space for mounting the outer tube of the soot blower provided in the boiler body can be reduced, and abnormal swinging of the outer tube is eliminated, so that safety is improved and reliability is improved.

〔The invention's effect〕

As described above in detail, the long-removal type soot blower according to the present invention can effectively prevent the outer tube from swaying due to resonance by inverter control, so that the passage of the outer tube of the soot blower into the furnace is reduced. It is possible to make the water-cooled furnace wall of a furnace such as a boiler device more compact, and there is no occurrence of accidents such as damage to the furnace wall tube due to contact with the outer tube, thus further improving safety and reliability. Can be enhanced. Furthermore, since the jet of the medium injected from the injection port of the soot blower does not shake the outer tube,
It is possible to perform uniform cleaning with a fixed predetermined trajectory without being disturbed, so that the cleaning efficiency of the soot blower can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing the structure of a long-removal type soot blower exemplified in the embodiment of the present invention, FIG. 2 is a graph showing the vibration characteristics of the long-removal type soot blower of the present invention, and FIG. It is a graph which shows the vibration characteristic of a slip-on type sootblower. DESCRIPTION OF SYMBOLS 1 ... Main valve 2 ... Trolley 3 ... Inner tube 4 ... Outer tube 5 ... Roller bracket 6 ... Furnace wall tube 7 ... Injection port 8 ... Stop limit switch 9 ... Reverse switch 10 ...... Limit switch for inverter control 11 …… Injection medium

Claims (5)

(57) [Claims] 1. A jet port for jetting a medium is provided at a tip end,
And has a long outer tube to be pulled forward and backward while rotating at a set speed, and to insert and remove into the furnace,
In the outer tube, an inner tube for introducing a jet medium is slidably provided inside the outer tube, and a medium is ejected from a tip portion of the outer tube to clean the surface of the furnace wall tube. In a soot blower, move the outer tube forward while rotating it at the set number of revolutions and insert it into the furnace to a maximum of 1.5 m before approaching the maximum insertion position.
A long-displacement soot blower, comprising: a limit switch at a position; and control means for gradually reducing the rotation speed of the outer tube by controlling an inverter. 2. The inverter control method according to claim 1, wherein the inverter control limit switch is provided near a maximum insertion position of the outer tube in a specific section before a reverse rotation limit switch for reversing the rotation direction of the outer tube. The long pull-out type soot blower according to claim 1. 3. An ejection port for ejecting a medium is provided at the tip end,
And has a long outer tube to be pulled forward and backward while rotating at a set speed, and to insert and remove into the furnace,
In the outer tube, an inner tube for introducing a jet medium is slidably provided inside the outer tube,
In the operation method of the long-removal-type soot blower that cleans the surface of the furnace wall tube by injecting a medium from the tip of the outer tube, the outer tube is advanced while rotating at a set number of revolutions and inserted into the furnace. When the specified distance from the maximum insertion position of the outer tube is approached, the rotation speed of the outer tube is gradually reduced by the inverter control, and the rotation is reversed near the maximum insertion position of the outer tube. Gradually raise
By rotating the outer tube at a specific distance from the maximum insertion position and restoring the rotation speed of the outer tube to the set rotation speed, the vibration caused by resonance near the maximum insertion position of the outer tube is controlled. Operation method of differential soot blower. 4. When the forward speed of the outer tube is approached a specific distance from the maximum insertion position of the outer tube, the forward speed of the outer tube is reduced from the set forward speed of the outer tube. The method according to claim 3, wherein the speed of the outer tube is returned to the original set speed at a specific distance. 5. The operating method for a long-removable soot blower according to claim 3, wherein a specific distance from the maximum insertion position of the outer tube is 1.5 m at a maximum.