JP3575503B2 - Large double suction centrifugal fan - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a large-sized double suction centrifugal fan having suction ports on both sides and a large size.
[0002]
[Prior art]
As an example of an apparatus in which a large double suction centrifugal fan is used, the gas flow of a boiler combustion device will be described with reference to the system diagram of FIG. 3. Combustion air of the boiler 1 is air sent from a forced blower 2. After being heated by the steam air heater 3, the air is further heated by exchanging heat with the exhaust gas from the boiler 1 by the air preheater 4 and sent to the burner 6 of the boiler 1 through the combustion air supply pipe 5. Has become.
[0003]
Fuel 7 such as fuel oil or pulverized coal is supplied to the burner 6 of the boiler 1 and mixed with combustion air to burn in the furnace of the boiler 1 and generate steam in a heat transfer tube (not shown). It has become.
[0004]
Exhaust gas generated by the combustion in the furnace of the boiler 1 is introduced into an air preheater 4 through an exhaust gas discharge pipe 8 and exchanges heat with the combustion air. Thereafter, dust is removed by an electric precipitator 9, and air is discharged from a chimney 10. To be released.
[0005]
When the fuel 7 is completely burned in the furnace of the boiler 1, no soot is produced. However, since the amount of nitrogen oxides contained in the exhaust gas is increased, a part of the exhaust gas is reduced to reduce the nitrogen oxides contained in the exhaust gas. The boiler 1 is recirculated, and the combustion temperature in the furnace of the boiler 1 is lowered to slightly moderate the combustion, thereby suppressing the generation of nitrogen oxides.
[0006]
Therefore, between the exhaust gas discharge pipe 8 and the combustion air supply pipe 5, a large-sized double suction centrifugal fan 11 is provided as an exhaust gas mixing ventilator.
[0007]
FIG. 4 is a front view showing an example of a large-sized double suction centrifugal fan 11, and FIG. 5 is a sectional view taken along line V-V in FIG. 4. The suction ports 13 and 14 are connected to the exhaust gas discharge pipe 8 in FIG. 3 by a duct (not shown).
[0008]
A rotating shaft 16 that is driven to rotate by a motor 15 penetrates the volute 12, and an impeller 17 is attached to the rotating shaft 16 as shown in FIG.
[0009]
When the impeller 17 is rotated together with the rotary shaft 16 by the motor 15, the impeller 17 sucks exhaust gas from the suction ports 13 and 14 on both sides in the axial direction of the rotary shaft 16 and raises the pressure, and the exhaust port 18 in FIG. After that, the exhaust gas is sent to the combustion air supply pipe 5 in FIG.
[0010]
In order to adjust the amount of exhaust gas sucked by the large-sized double suction centrifugal fan 11, a plurality of dampers 19 are provided in one suction port 13 and a plurality of dampers 20 are also provided in the other suction port 14. Is established.
[0011]
FIG. 6 is a plan view showing an example of the suction ports 13 and 14 of the conventional large-sized double suction centrifugal fan 11, and FIG. 7 is a front view of FIG. The base ends of the turning levers 22 are fixed to the ends of all the turning shafts 21 fixed to the center of the damper 19, and the tip of the turning lever 22 is pivotally attached to one connecting bar 23. By connecting the connection bar 23 to the tip of a drive lever 25 rotated by the opening / closing drive device 24 and displacing the connection bar 23 in the longitudinal direction, all the dampers 19 arranged in parallel to the suction port 13 on one side are connected. The opening degree of can be adjusted all at once.
[0012]
Similarly, at the suction port 14 on the other side, the base ends of the rotation levers 27 are fixed to one ends of all the rotation shafts 26 fixed to the centers of the dampers 20 (see FIG. 6) arranged side by side. The tip of the rotating lever 27 is pivotally connected to one connecting bar 28, and the connecting bar 28 is connected to the tip of a driving lever 30 rotated by a damper opening / closing drive device 29, and the connecting bar 28 is displaced in the longitudinal direction. By doing so, the openings of all the dampers 20 juxtaposed to the suction port 14 on the other side can be adjusted simultaneously.
[0013]
As described above, the drive source for adjusting the opening degree of the dampers 19 and 20 is divided into the two damper opening / closing drive devices 24 and 29 by the suction port 13 on one side and the suction port 14 on the other side. Is large, and if the opening degree adjustment of all the dampers 19 and 20 is attempted to be operated by one damper opening / closing drive device, the operation torque becomes large and it becomes impossible.
[0014]
[Problems to be solved by the invention]
In the conventional large-sized double suction centrifugal fan 11, the openings of the dampers 19, 20 are simultaneously adjusted for each of the two suction ports 13, 14 on both sides. If any one of them fails, the gas can be sucked only from one side of the two suction ports 13 and 14 on both sides in some cases, and the gas pressure on both sides of the impeller 17 shown in FIG. As a result, the impeller 17 is pushed in the axial direction of the rotating shaft 16 due to a difference in pressure between the right and left sides of the gas, causing a displacement.
[0015]
The present invention eliminates such a drawback, and prevents the impeller of the large-sized double suction centrifugal fan from being pushed in the axial direction even if one of the two driving systems for opening and closing the damper fails. It is an object of the present invention to provide a suction centrifugal fan.
[0016]
[Means for Solving the Problems]
The present invention connects approximately half of the plurality of dampers arranged in parallel to one suction port and approximately half of the plurality of dampers arranged in parallel to the other suction port. Connected to one damper opening and closing drive,
The other half of the dampers arranged side by side with the one suction port and the remaining half of the dampers arranged side by side with the other suction port are connected to each other to open and close another damper opening / closing drive device. The present invention relates to a large-sized double suction centrifugal fan which is connected.
[0017]
Further, in the large-sized double suction centrifugal fan, the dampers connected to the one damper opening / closing drive device are every other damper among a plurality of dampers arranged in parallel at the suction ports on both sides,
It is preferable that a damper connected to the other damper opening / closing drive device is the remaining damper among a plurality of dampers arranged in parallel at the suction ports on both sides.
[0018]
Therefore, approximately half of the plurality of dampers arranged side by side on one side of the suction port and approximately half of the plurality of dampers arranged side by side on the other side of the suction port are one damper. The opening degree is adjusted by the opening / closing drive device, and the remaining substantially half of the dampers arranged side by side with the one-side suction port and the remaining substantially half of the dampers arranged side by side with the other-side suction port. However, the opening is adjusted by another damper opening / closing drive device, and even if one of the two damper opening / closing drive devices fails, the damper opening of the suction ports on both sides becomes substantially the same, and both sides of the impeller Gas pressure is always balanced so that the impeller is never pushed in the axial direction of the rotating shaft.
[0019]
Further, the dampers connected to one damper opening / closing drive are alternate dampers among a plurality of dampers arranged in parallel at the suction ports on both sides, and the dampers connected to the other damper opening / closing drive are used. In the case where the remaining dampers of the plurality of dampers arranged in parallel on the suction ports on both sides are used, one of the dampers arranged in parallel on the suction ports on both sides by one damper opening / closing drive device. The opening degree of every other damper is adjusted, and the remaining dampers of the plurality of dampers arranged in parallel at the suction ports on both sides are adjusted by other damper opening / closing drive devices.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
FIG. 1 is a plan view showing an example of a mode for carrying out the present invention, FIG. 2 is a front view of FIG. 1, and a suction port 13 on one side of a spiral chamber 12 of a large-sized double suction centrifugal fan has: A plurality of dampers 31a, 31b, 31c, 31d, 31e, 31f, 31g, 31h, 31i, 31j, 31k, 31m are provided side by side, and a plurality of dampers 32a, 32b are similarly provided in the suction port 14 on the other side. , 32c, 32d, 32e, 32f, 32g, 32h, 32i, 32j, 32k, and 32m.
[0022]
A plurality of dampers 31a, 31b, 31c, 31d, 31e, 31f, 31g. In 31h, 31i, 31j, 31k, and 31m, the base ends of the rotation levers 34 are respectively attached to one ends of the rotation shafts 33 fixed to the centers of the other dampers 31a, 31c, 31e, 31g, 31i, and 31k. The other end of each of the rotating levers 34 is pivotally attached to one connecting bar 35, and the connecting bars 35 are displaced in the longitudinal direction, so that every other damper 31a, 31c, 31e, 31g in one group is formed. , 31i, and 31k can be simultaneously adjusted.
[0023]
Further, one end of a rotating shaft 36 fixed to the center of the remaining dampers 31b, 31d, 31f, 31h, 31j, 31m located between the other dampers 31a, 31c, 31e, 31g, 31i, 31k. Also, the base end of each of the rotating levers 37 is fixed, and the distal end of each of the rotating levers 37 is pivotally attached to another connecting bar 38 different from the above, and the connecting bar 38 is displaced in the longitudinal direction. The openings of the other alternate dampers 31b, 31d, 31f, 31h, 31j, and 31m, which are the other group, can be simultaneously adjusted.
[0024]
Similarly to the above, every other damper 32a, 32b, 32c, 32d, 32e, 32f, 32g, 32h, 32i, 32j, 32k, 32m arranged in parallel with the suction port 14 on the other side. The base ends of the rotating levers 40 are fixed to one ends of the rotating shafts 39 fixed to the centers of the dampers 32a, 32c, 32e, 32g, 32i, and 32k, respectively. By pivoting on the connecting bar 41 and displacing the connecting bar 41 in the longitudinal direction, the openings of the dampers 32a, 32c, 32e, 32g, 32i, and 32k, which are one group, can be adjusted at the same time.
[0025]
Further, the rotation is fixed to the center of the remaining alternate dampers 32b, 32d, 32f, 32h, 32j, and 32m between the alternate dampers 32a, 32c, 32e, 32g, 32i, and 32k. The base end of the rotating lever 43 is also fixed to one end of the shaft 42, and the distal end of each rotating lever 43 is pivotally attached to another connecting bar 44 different from the above, and the connecting bar 44 is moved in the longitudinal direction. By the displacement, the opening degree of the other alternate dampers 32b, 32d, 32f, 32h, 32j, and 32m that are the other group can be adjusted at the same time.
[0026]
Damper opening / closing driving devices 45 and 46 are attached to the lower portions of the suction ports 13 and 14, respectively.
[0027]
Further, two rotating shafts 47 and 48 are rotatably supported by bearings 49 over the sides of the suction ports 13 and 14.
[0028]
A distal end of a drive lever 50 that is vertically rotated by one damper opening / closing drive device 45 and a distal end of a link 51 whose base end is fixed to one rotary shaft 47 are connected by a rod 52. The one damper opening / closing drive device 45 can rotate one rotation shaft 47.
[0029]
A distal end of a drive lever 53 that is vertically rotated by the other damper opening / closing drive device 46 and a distal end of a link 54 whose base end is fixed to the other rotary shaft 48 are connected by a rod 55. The other damper opening / closing drive device 46 can rotate the other rotation shaft 48.
[0030]
The base ends of the links 56 and 57 are fixed to one of the rotating shafts 47, and the distal end of the link 56 is connected to the connecting bar 35 by a connecting rod 58. The distal end of the link 57 is connected to a connecting rod 59. To the connection bar 41.
[0031]
The base ends of the links 60 and 61 are fixed to the other rotating shaft 48, the distal end of the link 60 is connected to the connecting bar 38 by the connecting rod 62, and the distal end of the link 61 is connected to the connecting rod 63. To the connecting bar 44.
[0032]
Next, the operation of the device shown in FIGS. 1 and 2 will be described.
[0033]
When the drive lever 50 is turned up and down by one damper opening / closing drive device 45, one turn shaft 47 is turned via the rod 52 and the link 51.
[0034]
When the rotation shaft 47 rotates, the connecting bar 35 is displaced in the longitudinal direction via the link 56 and the connecting rod 58, and the connecting bar 41 is also displaced in the longitudinal direction via the link 57 and the connecting rod 59.
[0035]
For this reason, the opening degree of every other damper 31a, 31c, 31e, 31g, 31i, 31k of one group of the suction port 13 on one side is simultaneously adjusted, and at the same time, one of the suction ports 14 on the other side is adjusted. The opening degree of every other damper 32a, 32c, 32e, 32g, 32i, 32k of the group is also adjusted simultaneously.
[0036]
When the drive lever 53 is vertically rotated by the other damper opening / closing drive device 46, the other rotation shaft 48 is rotated via the rod 55 and the link 54.
[0037]
When the rotation shaft 48 rotates, the connecting bar 38 is displaced in the longitudinal direction via the link 60 and the connecting rod 62, and the connecting bar 44 is also displaced in the longitudinal direction via the link 61 and the connecting rod 63.
[0038]
For this reason, the opening degree of every other damper 31b, 31d, 31f, 31h, 31j, 31m of the other group of the suction port 13 on one side is simultaneously adjusted, and at the same time, the other of the suction ports 14 on the other side. The opening degree of every other damper 32b, 32d, 32f, 32h, 32j, 32m of the group is also adjusted simultaneously.
[0039]
As described above, the two systems of damper opening / closing driving devices are configured to adjust the opening degree of the damper for each half of both the suction ports 13 and 14.
[0040]
In this device, when one damper opening / closing drive device 45 fails, every other damper 31a, 31c, 31e, 31g, 31i, 31k of one group of the suction port 13 on one side and the other side have a different position. The opening degree of every other damper 32a, 32c, 32e, 32g, 32i, 32k of one group of the suction port 14 cannot be adjusted, but every other damper of the other group of the suction port 13 on one side. 31b, 31d, 31f, 31h, 31j, and 31m and every other damper 32b, 32d, 32f, 32h, 32j, and 32m of the other group of the suction port 14 on the other side are connected to the other damper opening / closing drive 46. Thus, the opening degree can be adjusted.
[0041]
Conversely, if the other damper opening / closing drive device 46 breaks down, every other damper 31b, 31d, 31f, 31h, 31j, 31m in the other group of the suction port 13 on one side, and the other. The opening degree of every other damper 32b, 32d, 32f, 32h, 32j, 32m in the other group of the suction port 14 on the side becomes uncontrollable, but every other group in the suction port 13 on the other side. The other dampers 32a, 32c, 32e, 32g, 32i, and 32k of one group of the suction port 14 on the other side have one damper opening / closing drive. The opening degree can be adjusted by the device 45.
[0042]
In this way, even if one of the damper opening / closing driving devices 45 and 46 fails, the suction ports 13 and 14 on both sides of the spiral chamber 12 of the large-sized double suction centrifugal fan have the same damper opening, and the impeller 17 ( The gas pressure on both sides (see FIG. 5) is always balanced, so that the impeller 17 is never pushed in the axial direction of the rotating shaft 16.
[0043]
In addition, the large-sized double suction centrifugal fan of the present invention is not limited to the illustrated example described above. In FIG. 1, the connecting bar 35 is disposed on the same side as the connecting bar 38 and the connecting bar 44 is provided. The dampers 31a, 31b, 31c, 31d, 31e, 31f, 31g. The layout of the drive system of 31h, 31i, 31j, 31k, 31m and the dampers 32a, 32b, 32c, 32d, 32e, 32f, 32g, 32h, 32i, 32j, 32k, 32m can be variously selected. A plurality of dampers 31a, 31b, 31c, 31d, 31e, 31f, 31g. 31h, 31i, 31j, 31k, 31m and 32a, 32b, 32c, 32d, 32e, 32f, 32g, 32h, 32i, 32j, 32k, 32m, instead of every other, every third or third It goes without saying that various changes can be made without departing from the gist of the present invention, such as the fact that the present invention may be connected.
[0044]
【The invention's effect】
As described above, according to the large-sized double suction centrifugal fan according to claims 1 and 2 of the present invention, even if one of the damper opening / closing driving devices fails, the damper opening of both suction ports is the same. Thus, there is an effect that the gas pressures on both sides of the impeller are always balanced so that the impeller is not pushed in the axial direction of the rotating shaft.
[Brief description of the drawings]
FIG. 1 is a plan view showing an example of an embodiment of a main part of the present invention.
FIG. 2 is a front view of FIG.
FIG. 3 is a system diagram showing a gas flow of a boiler.
FIG. 4 is a front view showing an example of a large double suction centrifugal fan.
FIG. 5 is a sectional view taken along line VV of FIG. 4;
FIG. 6 is a plan view showing an example of a suction port portion of a conventional large-sized double suction centrifugal fan.
FIG. 7 is a front view of FIG. 6;
[Explanation of symbols]
13 suction port 14 suction ports 31a, 31b, 31c, 31d, 31e, 31f, 31g. 31h, 31i, 31j, 31k, 31m Damper 32a, 32b, 32c, 32d, 32e, 32f, 32g, 32h, 32i, 32j, 32k, 32m Damper 45 Damper opening / closing drive 46 Damper opening / closing drive 51 Link 54 Link 56 Link 57 links 60 links 61 links

Claims (2)

Approximately half of the plurality of dampers arranged side by side on one side of the suction port and approximately half of the plurality of dampers arranged side by side on the other side of the suction port are connected to form one damper. Connected to the opening and closing drive,
The other half of the dampers arranged side by side with the one suction port and the remaining half of the dampers arranged side by side with the other suction port are connected to each other to open and close another damper opening / closing drive device. A large double suction centrifugal fan that is connected. The damper connected to the one damper opening / closing drive device is a damper connected to the other damper opening / closing drive device every other one of a plurality of dampers provided side by side at the suction ports on both sides. 2. The large-sized double-suction centrifugal fan according to claim 1, wherein the remaining one of the plurality of dampers arranged side by side at the suction ports on both sides is the remaining damper.

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