JPH1054544A - Damper for controlling flow of pulverized coal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily control the flow of pulverized coal and prevent the flow of pulverized coal from being deflected by providing two corrosion resistant passage opening/closing damper blades each having an arcuate cross section in such a manner that each of the blades is swingably supported on an axis disposed at the center of a passage of a pulverized coal pipe for pneumatically conveying pulverized coal to a plurality of burners so as to be oriented normal to the passage of the pipe. SOLUTION: Two damper blades 2 each having an arcuate surface 9 having the same cross section are provided in a rectangular pulverized coal passage 4 for pneumatically conveying pulverized coal to a plurality of burners of a boiler furnace in such a manner that each of the blades 2 is swingably supported on an axis 3 provided in the passage 4 through an arm 2'. A flat plate 5 is connected to the inside of the arcuate surface 9, and a ceramics plate is bonded to the damper blades 2, flat plates 5 and axis 3 to prevent these parts from being worn away by pulverized coal. By turning the blades 2 about the axis 3, the cross-sectional area of the passage 4 can be controlled and by turning the blades 2 symmetrically, the flow of the pulverized coal is prevented from channelling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulverized coal flow rate adjustment damper used for a plurality of pulverized coal pipes for carrying pulverized coal to each of a plurality of burners by air flow.

[0002]

2. Description of the Related Art In a boiler having a plurality of burners and performing pulverized coal combustion, coal is pulverized into pulverized coal by one pulverized coal machine, and a plurality of pulverized coals connected to the single pulverized coal machine are provided. Pulverized coal is transported to each burner by airflow through a pipe and burned. At this time, it is inevitable that a plurality of pulverized coal pipes in contact with one pulverized coal machine have different lengths and a different number of bend portions. Are not equal.

However, since the amount of pulverized coal supplied to each pulverized coal pipe is substantially proportional to the pressure loss of each pulverized coal pipe, the amount of pulverized coal supplied to each pulverized coal pipe is made equal to perform stable combustion. Therefore, it is necessary to take measures for equalizing the pressure loss of each pulverized coal pipe.

As a countermeasure, an orifice is generally installed in each pulverized coal pipe so that the pressure loss of each pulverized coal pipe is equalized. However, once the orifice is installed, the orifice is easily installed. It could not be changed, and re-adjusting it later when there was an imbalance in the amount of pulverized coal was a tedious task.

Therefore, a method of adjusting the flow rate of pulverized coal by attaching a damper to the pulverized coal pipe has been used. Examples of this conventional damper are shown in FIGS.

The damper shown in FIG. 5 is provided with a damper accommodating portion 21 in a pulverized coal passage 23, in which the damper blade 20 can be accommodated. It is designed to adjust the degree of opening of the flow path by moving in and out.

Further, the damper shown in FIG.
3, a damper shaft 31 is provided, and a damper blade 30 is rotatably mounted on the damper shaft 31. The damper blade 30 is rotated about the shaft 31 to open and close to adjust the opening degree of the flow path. It was made.

[0008]

In the conventional damper using only one plate-like blade, there is a problem that the center of the pulverized coal stream is deviated from the center of the pulverized coal pipe.

In the conventional damper shown in FIG. 5, since the damper accommodating portion protrudes from the pulverized coal passage, if the number of damper blades is increased to eliminate the drift of the pulverized coal flow, a large space is required for installation. There was a problem of doing.

Further, in the damper shown in FIG. 6, the shaft 3 of the blade is used to open and close the damper blade 30 smoothly.
1 and the inner wall of the pulverized coal pipe 32, it is necessary to secure a certain distance. Therefore, when the opening of the damper is small, the relative proportion of the pulverized coal flowing from this gap increases, and the opening of the damper is reduced. Even if it is small, the pulverized coal flow rate cannot be reduced, and there is a problem that adjustment is difficult.

According to the present invention, the installation space is small, the flow rate of pulverized coal can be easily adjusted, and the flow rate of pulverized coal is controlled for each pulverized coal pipe without causing a drift in the pulverized coal flow in the pulverized coal pipe. An object of the present invention is to provide a pulverized coal flow rate adjustment damper for eliminating a difference in pulverized coal flow rate between pulverized coal pipes.

[0012]

[Means for Solving the Problems]

1. The pulverized coal flow rate adjustment damper of the present invention is disposed at the center of each of the pulverized coal pipe passages of a plurality of independent pulverized coal pipes for carrying pulverized coal by airflow to each of the plurality of burners, so as to be orthogonal to the shaft and the shaft. A wear-resistant damper blade for opening and closing a passage having two arc-shaped cross sections that are coaxially supported and rotatable about a coaxial axis is provided.

2. The pulverized coal flow rate adjusting damper of the present invention is characterized in that, in the present invention 1, a flat plate is attached inside the arc-shaped cross section of the damper blade.

3. The pulverized coal flow rate adjusting damper according to the present invention is characterized in that, in the present invention 1 or 2, the damper casing has a cylindrical shape whose cross section is a concentric circle having substantially the same size as the arc-shaped cross section of the damper blade.

4. The pulverized coal flow rate adjustment damper according to any one of the first, second, and third aspects of the present invention, wherein the two damper blades are opened and closed from only one side of the damper casing to the upstream side or the downstream side of the pulverized coal flow. It is made possible.

5. Further, the pulverized coal flow rate adjusting damper of the present invention may be arranged such that
The opening degree of the damper blade is adjusted by a signal of a flow rate detector for detecting a flow rate of pulverized coal at a burner inlet.

According to the first aspect of the present invention, a rotation orthogonal to the pulverized coal passage is provided at the center of each pulverized coal passage, and two damper blades having an arc-shaped cross section are coaxially rotatably supported around the axis. The opening and closing of the damper blade can be simultaneously performed from the left and right of the pulverized coal pipe passage. As a result, the pulverized coal flow passing through the damper portion passes through the center of the pulverized coal passage, and does not flow unevenly.

According to the second aspect of the present invention, the flow of the pulverized coal can be smoothly reduced by the flat plate attached inside the arc-shaped cross section of the damper blade.

According to the third aspect of the present invention, the entire damper can be made compact by forming the cross section of the damper casing into a cylindrical shape having a concentric circle having substantially the same size as the arc-shaped cross section of the damper blade. At the same time, it is possible to make the gap between the damper blade and the damper casing very small, and by reducing the pulverized coal flow flowing from this gap, it is possible to adjust the pulverized coal flow especially when the damper opening is small. It can be done easily.

According to the fourth aspect of the present invention, since two damper blades can be opened and closed from only one side of the damper casing to the upstream side or the downstream side of the pulverized coal flow, the operation space for the damper blades is reduced. Reduced.

According to the fifth aspect of the present invention, the opening of the damper blade is adjusted by the signal of the flow detector for detecting the flow rate of the pulverized coal at the burner inlet, and the adjustment of the damper blade can be easily and automatically performed. .

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a pulverized coal flow rate adjusting damper according to the present invention will be described with reference to FIGS. In the embodiment, the damper blade is provided so as to open and close on the downstream side.

Pulverized coal is pneumatically conveyed from one pulverized coal machine (not shown) in the direction indicated by arrow 7, and the pulverized coal is air-conveyed to one of a plurality of boiler furnace burners (not shown). In the straight tubular pulverized coal passage 4, a damper blade 2 having an arc surface 9 having two equal cross sections is provided via an arm 2 '.
The pulverized coal passage 4 is rotatably supported about the axis of the shaft 3 provided on each side of the pulverized coal passage 4. As shown in FIG. 2, the rotating shaft 3 is disposed at the center of the pulverized coal passage 4 so as to be orthogonal to the passage 4. 10 is the pulverized coal passage 4,
3 shows a damper formed by a damper blade 2, a shaft 3, and the like.

The damper blades 2 on both sides of the damper 10
A damper casing 1 that accommodates the damper blade 2 is provided at a position where the damper blade 2 is provided.
The section is formed in a cylindrical shape that is substantially the same size as the arc surface 9 of the damper blade 2 and is concentric.

The damper blade 2 whose two cross-sections form an arc surface 9 is rotated by levers 6, 6 attached to one side of the damper casing 1 and connected to the arms 2 ', 2'. The shaft 3 is closed from the upstream side to the downstream side around the shaft 3.

Inside the arc surface 9 of the damper blade 2, flat plates 5 connected to both ends of the arc are provided. The damper blade 2, the flat plate 5, the shaft 3 and the like have a wear-resistant structure such as attaching a ceramic plate to prevent wear due to pulverized coal. The lever 6
May be operated manually, or the damper blade 2 may be automatically operated by connecting an air cylinder or the like. Reference numeral 7 denotes a flow of the pulverized coal conveyed by gas, and reference numeral 8 denotes a flange connecting the damper 10 to the pulverized coal pipe.

In the present embodiment configured as described above, the two damper blades 2 are rotated around the axis of the shaft 3 via the lever 6 so that the two damper blades 2 And moves downstream from the open position shown by the solid line to the position shown by the alternate long and short dash line, whereby the area of the pulverized coal flow path 4 can be adjusted.

The two damper blades 2 are connected to the pulverized coal passage 4
The pulverized coal flows through the center of the pulverized coal passage 4 simultaneously and symmetrically around the axis of the shaft 3 at the center, and no drift occurs.

Further, the flow of the pulverized coal can be smoothly reduced by the flat plate 5 provided inside the arc surface 9 of the damper blade 2.

Further, on both sides of the damper, the circular arc surfaces 9 of the damper blade 2 are housed so as to accommodate the damper blade 2.
Since the cylindrical damper casing 1 having a concentric circle substantially the same size as that of the damper casing 1 is provided, the entire damper is made compact, and the damper blade 2 and the damper casing 1 are formed.
To reduce the flow of pulverized coal flowing from this gap when the opening of the damper blade 2 is small,
Adjustment of the pulverized coal flow rate can be facilitated.

In addition to the above, since the damper blade 2 is operated only from one side of the damper casing 1, the operation space for the damper blade 2 can be reduced.

A second embodiment of the present invention will be described with reference to FIG. The structure, configuration, and the like of each part of the present embodiment are almost the same as those of the first embodiment of the present invention, except that the damper blade 2 having two arc-shaped cross-sections The pulverized coal passage 4 is adjusted so as to close to the upstream side.

In the present embodiment, since the portions to be worn are the arc surface 9 of the damper blade 2 and the inner surface of the damper 10 on the upstream side thereof, the wear is performed in the same manner as in the first embodiment of the present invention. Abrasion resistant structure.

In the first and second embodiments of the present invention, the plurality of dampers 10 are attached to each of the plurality of pulverized coal pipes 15 and the damper blades 2 are located near the inlet of the burner 12 of the furnace 11. Pulverized coal flow detector 13 provided
FIG. 4 shows an example in which the control is automatically performed by the signal of FIG.
Shown in

Four pulverized coal pipes 15 are attached to one mill 16 for pulverizing coal into pulverized coal, and each of the four pulverized coal pipes 15 is attached to each of four burners 12 mounted horizontally on the front of the furnace 11. Is connected. A flow detector 13 is provided near the inlet of each burner 12, and a signal of the pulverized coal flow detected by the flow detector 13 is transmitted to each damper 10 via a control device 14, The opening degree of the damper blade 2 is adjusted. Depending on the length of each pulverized coal pipe 15 and the number of bends, each burner 1
However, in this device,
The opening degree of the damper blade 2 of each damper 10 can be automatically adjusted so that the flow rate of the pulverized coal supplied to each burner 12 becomes the same.

[0036]

According to the present invention, the following effects can be obtained since the present invention has the configuration described in each claim.

That is, since the two arc-shaped damper blades can be simultaneously opened and closed from the left and right, the pulverized coal flow can be controlled for each pulverized coal pipe without causing a drift in the pulverized coal flow. Can be eliminated for each pulverized coal pipe, and thereby stable combustion can be achieved.

Further, the flow of the pulverized coal can be reduced smoothly by attaching the flat plate inside the arc-shaped cross section of the damper blade. Further, by making the damper casing into a cylindrical shape having a concentric circle having a cross section substantially the same size as the arc-shaped cross section of the damper blade, it is possible to make the entire damper compact, and to reduce the size of the damper blade and the damper casing. The pulverized coal flow rate can be easily adjusted by reducing the gap between the two.

By operating the two damper blades from only one side of the damper casing, the required space can be reduced.

Further, the opening of the damper blade can be easily and automatically adjusted by the signal of the flow rate detector for detecting the flow rate of the pulverized coal at the burner inlet.

[Brief description of the drawings]

FIG. 1 is a horizontal sectional view of a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of the first embodiment of the present invention.

FIG. 3 is a vertical sectional view of a second embodiment of the present invention.

FIG. 4 is a perspective view of the first and second embodiments of the present invention, in which a plurality of pulverized coal pipes are mounted on a plurality of pulverized coal pipes, and a damper blade is controlled by a pulverized coal flow rate detector provided near a burner inlet. FIG. 3 is a system diagram of an example configured to perform the processing.

FIG. 5 is a vertical sectional view of a first example of a damper provided in a conventional pulverized coal passage.

FIG. 6 is a vertical sectional view of a second example of a damper provided in a conventional pulverized coal passage.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Damper casing 2 Damper blade 3 Shaft 4 Pulverized coal passage 5 Flat plate 6 Lever 7 Pulverized coal flow 8 Flange 9 Circular surface 10 Damper 11 Furnace 12 Burner 13 Flow detector 14 Control device 15 Pulverized coal pipe 16 Mil

Claims (5)

[Claims] 1. A shaft which is coaxially supported and coaxial with an axis arranged at the center of each pulverized coal passage of a plurality of independent pulverized coal pipes for carrying airflow of pulverized coal to each of a plurality of burners, respectively, so as to be orthogonal to the passage. A pulverized coal flow rate adjustment damper comprising: a wear-resistant damper blade for opening and closing a passage having two arc-shaped cross sections rotatable around a center. 2. The pulverized coal flow rate adjustment damper according to claim 1, wherein a flat plate is attached inside the arc-shaped cross section of the damper blade. 3. The pulverized coal flow rate adjustment according to claim 1, wherein the damper casing has a cylindrical shape having a cross section having a center circle having substantially the same size as an arc-shaped cross section of the damper blade. damper. 4. The open / close operation of the two damper blades from only one side of the damper casing to the upstream or downstream of the pulverized coal flow.
The pulverized coal flow rate adjustment damper according to any one of 2 and 3. 5. An opening of said damper blade is adjusted by a signal of a flow rate detector for detecting a flow rate of pulverized coal at a burner inlet.
The pulverized coal flow rate adjustment damper according to any one of items 3 and 4.