JP2012011273A - Dust collector and method for operating dust collector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dust collector which collects microparticles, when backwashing is made, to prevent the microparticles from adhering to a filter cloth when dust collection is started again, consequently to restrain a pressure loss from increasing and make its maintenance easy; and to provide a method for operating the dust collector when backwashing is made.SOLUTION: The dust collector 100 includes a bag filter 101 which is provided with a filter cloth 111 which hangs down in a dust chamber 110 and a backwashing dust-collecting filter cloth 112, and brushes off dust 117, which is collected on the external side of the filter cloth when backwashing is made, and then collects the brushed-off dust by means of the backwashing dust-collecting filter cloth. A method for operating the dust collector is provided. In addition, the dust collector includes a bag filter which is provided with a filter cloth which hangs down in a dust chamber, and brushes off dust, which is collected on the external side of the filter cloth when backwashing is made, and then collects the brushed-off dust by means of another filter cloth in the same bag filter or a filter cloth in another bag filter. A method for operating the dust collector is provided.

Description

  The present invention relates to a dust collector for removing dust contained in a gas, and an operation method during backwashing of a bag filter of the dust collector.

Conventionally, a bag filter provided with a filter cloth for treating dust (particulate matter) contained in a gas is installed. Examples of the gas include exhaust gas generated when burning coal and heavy oil, and air. The above-mentioned bag filter is installed in the flue of power generation plants such as coal-fired and heavy oil-fired, industrial combustion equipment such as incinerators, etc., as well as a dust collector that is installed in the vicinity of a device that generates dust and performs environmental dust collection Also applies.
In general, a filter cloth having a circular cross section, an oval cross section, or the like is used. When gas flows in from the outer surface of the filter cloth and is exhausted through the inside of the filter cloth, dust that cannot pass through the filter cloth accumulates on the outer surface of the filter cloth.

  In order to remove dust on the outer surface of the filter cloth, backwashing is periodically performed. Bag filters are generally backwashed using a pulse jet. Backwashing by pulse jet introduces a gas flow such as air into the inner surface of the filter cloth, so that dust is removed by impact force and reverse airflow from the inner surface to the outer surface of the filter cloth, and dust is collected at the bottom of the bag filter by downward airflow. To do.

  Patent Document 1 discloses a dust collector that includes a bag filter that performs backwashing with a back pressure drop-off type, and dust that re-scatters from the backwashed bag filter is provided on the downstream side of the bag filter. Discloses a back-washing method for a dry dust collector in which clean air that has been collected by the filter and passed through a dust collector is allowed to flow again into the filtration chamber.

Japanese Patent Laid-Open No. 3-12210 (Claim 1, page 2, lower right column, line 19 to page 3, lower right column, line 6, FIGS. 1 to 4)

  The dust removed by backwashing settles in the bag filter. The sedimentation rate of dust (particles) depends on the size of the dust as expressed by the Stokes equation. That is, after backwashing, relatively large dust settles quickly, but fine dust is floating in the bag filter. When dust collection is resumed without sufficiently securing the settling time of dust, the fine dust that floats reattaches to the outer surface of the filter cloth. As a result, the filter cloth is clogged and the pressure loss increases, so the life of the filter cloth is shortened. In general, a plurality of filter cloths are installed inside the bag filter. However, it is necessary to replace all the filter cloths at the time of maintenance and inspection, and the time required for the replacement becomes long.

  The present invention collects fine particles during backwashing and prevents fine particles from adhering to the filter cloth when dust collection is resumed, thereby suppressing an increase in pressure loss and maintaining maintenance. It is an object of the present invention to provide a dust collector that makes it easy to operate and a method of operating the dust collector during backwashing.

  In order to solve the above-mentioned problems, the present invention is a dust collector for removing dust in a gas, including a bug filter and an induction fan in order from the upstream side in a flue through which the gas flows, A bag filter includes a dust chamber, a filter cloth that is suspended in the dust chamber and collects dust during gas processing, and a filter that is suspended in the dust chamber and dropped from the filter cloth during backwashing. A backwashing dust collecting filter cloth for collecting a portion, a first upper space provided on an upper part of the filter cloth and isolated from the dust chamber through the filter cloth, and the backwashing dust collecting A first upper space and a second upper space provided on an upper portion of the filter cloth and isolated from the dust chamber via the backwashing dust collecting filter cloth; In the upper space and the second upper space, Air source for backwashing supplying air for washing are connected, backwash dust collecting filter cloth for induction fan to the second upper space to provide a dust collecting device connected.

  Further, in the above dust collector, the step of stopping the exhaust of the first upper space by the attraction fan when the bag filter is backwashed, and the backwash air source to the first upper space. Supplying air for backwashing and applying an air flow to the inside of the filter cloth to remove dust collected on the outside of the filter cloth; and discharging the gas from the second upper space to discharge the gas A method of operating a dust collector comprising: sucking the inside of a backwashing dust collecting filter cloth and collecting the dust that has been removed with the backwashing dust collecting filter cloth.

  In the above invention, since exhaust of the first upper space is stopped and exhaust of the second upper space is performed at the time of backwashing, the backwashing air is supplied to the first upper space and dust is removed. Thereafter, the dust that has been removed is selectively collected by a backwashing dust collecting filter cloth installed in the same bag filter. As a result, the life of the filter cloth can be extended. The backwashing dust collection filter cloth is clogged and needs to be replaced periodically. However, during maintenance, only the backwashing dust collection filter cloth needs to be replaced, and the number of replacements can be reduced, facilitating maintenance. The required time is also shortened.

In the dust collector, a plurality of the bag filters may be installed. With such a configuration, when one bag filter is backwashed, dust collection can be continued with the remaining bag filters.
In the dust collector, the dust chamber may include a plurality of filter cloths and a plurality of backwash dust collecting filter cloths. With such a configuration, the filter cloth can be back-washed while continuing the dust collection.

  In the method for operating the dust collector, in the step of collecting dust with the backwashing dust collecting filter cloth, it is preferable that gas is supplied to the first upper space.

  In the above invention, for example, by circulating the gas exhausted from the second upper space to the first upper space, the pressure loss in the bag filter can be suppressed, and the load of the attracting fan for collecting the backwashing dust can be reduced. . In addition, the filter cloth that collects dust during gas treatment, which is subject to backwashing, is kept at a relatively positive pressure. Slow fine dust can be prevented from reattaching to the surface of the filter cloth, and as a result, the backwash dust collecting filter cloth is induced to collect fine dust. The gas to be supplied may be a gas exhausted from the second upper space as described above, or a gas outside the system (for example, air) may be used as a supply source. For example, it is possible to generate a downward flow by increasing the amount of gas supplied to the first upper space to be greater than the amount of circulation from the second upper space. As a result, the life of the filter cloth can be prolonged. At this time, a predetermined amount or more of gas is supplied to the inside of the bag filter. However, an operation of removing the excessively supplied gas may be performed simultaneously with the settled ash treatment.

  In the above-described invention, it is preferable that a precharge unit that charges the dust in the gas is further provided on the upstream side of the bag filter. It is preferable that the method further includes a step of applying an electric charge to the dust in the gas on the upstream side of the bag filter.

  The charged dust tends to aggregate with coarse dust on the filter cloth surface. For this reason, the collection rate of the fine dust in a bag filter improves. By agglomerating dust, it becomes easy to drop off from the filter cloth during backwashing. Furthermore, fine dust floating in the dust chamber can be reduced and the sedimentation speed can be increased. As a result, an increase in pressure loss can be further suppressed, and the life of the filter cloth and the backwashing dust collecting filter cloth can be further extended.

  Further, the present invention is a dust collecting device for removing dust in a gas, comprising a plurality of bug filters and an induction fan in order from an upstream side in a flue through which the gas flows, Each is provided with a dust chamber, a filter cloth that is suspended in the dust chamber and collects dust during gas processing, and is provided on the filter cloth, and is isolated from the dust chamber through the filter cloth. There is provided a dust collector including an upper space, a backwash air source for supplying backwash air to the upper space, and a backflow fan connected to the upper space.

  In the dust collector, the step of stopping the exhaust of the upper space by the attraction fan during backwashing of the one bag filter, and the upper space of the bag filter to be backwashed from the backwash air source Supplying the air for backwashing to blow off the dust collected on the outside of the plurality of filter cloths by supplying airflow to the inside of the plurality of filter cloths of the bag filter to be backwashed; Supplying gas from the fan to the upper space, discharging gas from the upper space of the other bag filter, and discharging the dust removed from the dust chamber of the backwashed bag filter And a method of operating the dust collector including the steps of transporting to the dust chamber of the other bag filter and collecting with the filter cloth of the other bag filter.

  In the above-described invention, a backflow fan is connected to the upper space, and gas is supplied from the backflow fan to the upper space, so that a downward flow is generated in the dust chamber and dust settling is promoted. Furthermore, the sedimentation of fine dust in a floating state with a slow sedimentation speed is accelerated, and these fine dusts are conveyed to another bag filter that continues the dust collection. In other bag filters, the fine dust removed by backwashing is aggregated and collected in the already collected dust. For this reason, when dust collection of a bag filter that has been backwashed is resumed, fine dust is reattached to the backwashed filter cloth, preventing the filter cloth from becoming clogged and increasing pressure loss. it can. As a result, the life of the filter cloth can be extended. Moreover, when the other bag filter which collected the fine dust is backwashed, the sedimentation speed of dust becomes large and the backwashing effect can be enhanced.

  Further, the present invention is a dust collector for removing dust in a gas, the flue through which the gas circulates includes, in order from the upstream side, a bug filter and an induction fan, and the bag filter includes a dust chamber, A plurality of filter cloths suspended in the dust chamber and collecting dust at the time of gas treatment, and provided on top of the plurality of filter cloths, and isolated from the dust chamber through the filter cloths, An upper space separated into a plurality of compartments by a partition wall, a backwash air source for supplying backwash air to each of the compartments, and a backflow fan in each of the compartments Provide connected dust collector.

  In the dust collector, when the bag filter is backwashed, the step of stopping exhaust by the induction fan in the compartment located above the filter cloth to be backwashed, and the backwash air source from the backwash air source. The backwashing air is supplied to the compartment located at the top of the filter cloth to be washed, and the airflow is applied to the inside of the filter cloth to be backwashed, thereby collecting on the outside of the backwashed filter cloth. A step of removing the generated dust, a step of supplying gas from the backflow fan to the compartment located above the filter cloth to be backwashed, and the partition located above the other filter cloth. A method of operating a dust collector, comprising: exhausting gas from a chamber and collecting the dust that has been removed with the other filter cloth.

  In the above invention, gas is supplied from the backflow fan to the compartment located at the top of the filter cloth to be backwashed, so that the sedimentation of the dust that has fallen off from the filter cloth to be backwashed is caused by the downward flow from the backflow fan. Promoted. In addition, a part of the dropped dust is collected by another filter cloth. At this time, fine dust aggregates in the dust collected on the other filter cloth. By adopting such a configuration, it is possible to accelerate sedimentation of fine dust that has a particularly slow sedimentation speed and is in a floating state. For this reason, even if dust collection is resumed after backwashing, re-collection of fine dust in a suspended state is suppressed, suppressing an increase in pressure loss due to clogging of the filter cloth, and extending the life of the filter cloth. be able to. Even if only one bag filter is provided, dust collection can be continued while backwashing is performed.

  In the above invention, the attracting fan for backwashing dust collecting filter cloth or the backflow fan may be the attracting fan. By doing so, the dust collector can be simplified.

  In the above-described invention, it is preferable that a precharge unit that charges the dust in the gas is further provided on the upstream side of the bag filter. It is preferable that the method further includes a step of applying an electric charge to the dust in the gas on the upstream side of the bag filter.

  The charged dust tends to aggregate with coarse dust on the filter cloth surface. For this reason, the collection rate of the fine dust in a bag filter improves. By agglomerating dust, it becomes easy to drop off from the filter cloth during backwashing. Furthermore, fine dust floating in the dust chamber can be reduced and the sedimentation speed can be increased. As a result, an increase in pressure loss can be further suppressed, and the life of the filter cloth and the backwashing dust collecting filter cloth can be further extended. It is also effective to charge and agglomerate fine dust with a backflow fan before conveying it to another bag filter.

The present invention collects fine dust that has fallen from the filter cloth by backwashing with a backwash dust collection filter cloth provided in the same bag filter, thereby suppressing an increase in the pressure loss of the bag filter. The life of the fabric can be extended. In addition, by installing a backflow fan, it is possible to promote sedimentation of fine dust. By extending the service life of the filter cloth, it is only necessary to replace the backwash dust collecting filter cloth during periodic inspection, so that maintenance management becomes easy.
When the fine dust dropped from the filter cloth by backwashing is collected by another bag filter, the fine dust aggregates into coarse dust on the outer surface of the filter cloth. For this reason, sedimentation of dust can be promoted at the time of backwashing other bag filters. Further, it prevents the fine dust from being collected on the backwashed filter cloth. As a result, the life of the filter cloth can be extended.

It is the schematic of the dust collector which concerns on 1st Embodiment. It is the schematic which shows an example of a precharge part. It is the schematic which shows another example of a precharge part. It is the schematic of the dust collector which concerns on 2nd Embodiment. It is the schematic of the dust collector which concerns on 3rd Embodiment. It is the schematic of the dust collector which concerns on 4th Embodiment. It is the schematic of the modification of the dust collector which concerns on 4th Embodiment. It is the schematic of the dust collector which concerns on 5th Embodiment. It is the schematic of the dust collector which concerns on 6th Embodiment. It is the schematic of the dust collector which concerns on 7th Embodiment. It is the schematic of the dust collector which concerns on 8th Embodiment. It is the schematic of the dust collector which concerns on 9th Embodiment.

Embodiments according to the present invention will be described below with reference to the drawings.
<First Embodiment>
FIG. 1 is a schematic view of a dust collector according to the first embodiment. The dust collector 100 is installed in a flue on the downstream side of the boiler (combustion furnace) 150, and includes a bag filter 101 and an induction fan 102 in order from the upstream side. The boiler 150 is, for example, a coal-fired power generation coal boiler. A chimney 160 is installed on the downstream side of the attracting fan 102.

Combustion exhaust gas containing dust (particulate matter) generated in the boiler flows into the bag filter 101 on the downstream side. In this embodiment, a plurality of bag filters are installed in parallel with the flow of the combustion exhaust gas. FIG. 1 illustrates the case where three bag filters 101a, 101b, and 101c are provided. Each of the bag filters 101a to 101c has the same structure.
In the bag filter 101a, a plurality of filter cloths 111a and backwashing dust collecting filter cloths 112a are suspended in the dust chamber 110a. In FIG. 1, the number of backwashing dust collecting filter cloths installed in each bag filter 101a, 101b, 101c is one, but a plurality of backwashing dust collecting filter cloths may be provided.
The filter cloth 111a and the backwashing dust collecting filter cloth 112a are formed in a cylindrical shape or an envelope shape. The cross sections of the filter cloth 111a and the backwashing dust collecting filter cloth 112a are not particularly limited, and a circular shape, an oval shape, a pleated shape, or the like can be applied. As the backwashing dust collecting filter cloth 112a, the same thing as the filter cloth 111a may be used, or a filter cloth having a low pressure loss specification may be used. Examples of the filter cloth using low-pressure loss include a membrane filter, a surface uneven filter, and a fiber diameter increasing filter.

  An upper space is provided above the dust chamber 110a. The upper space is separated into a first upper space 113a and a second upper space 114a by a partition wall 115a. The first upper space 113a is provided above the plurality of filter cloths 111a, and is isolated from the dust chamber 110a via the filter cloths 111a. The first upper space 113a is connected to the induction fan 102 on the downstream side through the flue. The second upper space 114a is isolated from the dust chamber 110a through the backwashing dust collecting filter cloth 112a.

  As a modification of the dust collecting device of FIG. 1, a partition may be provided between the filter cloth 111a and the backwash dust collecting filter cloth 112a in the dust chamber 110a. The upper end of the partition is connected to a wall that separates the dust chamber 110a from the first upper space 113a and the second upper space 114a. The lower end is positioned with a gap so that the gas in the dust chamber 110a can flow.

  The lower part of the dust chamber 110a has a hopper shape, and the dust dropped from the filter cloth 111a is discharged from the dust chamber 110a by opening the valve 116a provided at the bottom.

A backwash air source 120 is provided outside the bag filter 101. The backwash air source 120 is connected to each of the bag filters 101a, 101b, and 101c. The backwash air source 120 is connected to the first upper space 113a and the second upper space 114a of the bag filter 110a through a pipe. At this time, the first upper space 113a and the second upper space 114a may be connected to the backwash air source 120 by separate pipes.
The backwash air source may be common to each bag filter as shown in FIG. 1, or a separate backwash air source may be provided for each bag filter.
In the pipes in the first upper space 113a and the second upper space 114a, nozzles 121a are respectively installed at positions corresponding to the filter cloth 111a and the backwashing dust collecting filter cloth 112a.

An attracting fan 130a for backwashing dust collecting filter cloth is provided outside the bag filter 101a. The backwashing dust collecting filter cloth attracting fan 130a is connected to the second upper space 114a through a pipe. Further, the attracting fan 130a for backwashing dust collecting filter cloth is connected to the first upper space 113a by being connected to the flue connecting the attracting fan 102 and the first upper space 113a.
In FIG. 1, each of the bag filters 101a, 101b, and 101c is provided with an attracting fan 130a, 130b, and 130c for backwashing dust collecting filter cloth. However, the backwashing dust collecting filter connected to each bag filter is provided. It is good also to share the cloth invitation fan.

A process of performing off-line backwashing in the dust collector 100 of FIG. 1 will be described below. Here, a case where the bag filter 101a is backwashed will be described.
The valve 103a installed between the boiler 150 and the bag filter 101a is closed, and the supply of combustion exhaust gas to the dust chamber 110a is stopped. The valve 104a installed between the bag filter 101a and the attracting fan 102 is closed. Thereby, the exhaust of the first upper space 113a by the attracting fan 102 is stopped.
The valves 103b and 103c between the boiler 150 and the other bag filters 101b and 101c and the valves 104b and 104c between the bag filters 101b and 101c and the induction fan 102 are opened. For this reason, dust collection by the bag filters 101b and 101c is continued.

  Next, the backwashing dust collecting filter cloth attracting fan 130a is activated. Valve 131a between second upper space 114a and backwashing dust collecting filter cloth attracting fan 130a, and valve between backwashing dust collecting filter cloth attracting fan 130a and first upper space 113a 132a is opened. The backwashing dust collecting filter cloth attracting fan 130a exhausts the second upper space 114a. As a result, an air flow is generated from the dust chamber 110a through the backwashing dust collecting filter cloth 112a toward the second upper space 114a.

The valve 122a installed between the first upper space 113a and the second upper space 114a of the bag filter 101a and the backwash air source 120 is opened. A backwash air stream is jetted from the nozzle 121a to the inside of the filter cloth 111a. Thereby, the dust deposited on the outer surface of the filter cloth 111a falls off from the filter cloth 111a. A plurality of valves 122a may be installed according to the number of filter cloths provided in the dust chamber.
At this time, when the valve 116a at the bottom of the dust chamber 110a is opened, a downward flow is generated inside the dust chamber 110a.
As described above, when a partition is provided between the filter cloth 111a and the backwashing dust collecting filter cloth 112a, a downward flow can be generated only on the filter cloth 111a side.

Coal-fired boiler ash usually has an average particle size of about 10 to 30 μm. Coarse dust 117 dropped off from the filter cloth 111a settles down to the lower part of the dust chamber 110a. In the present embodiment, the gas exhausted from the second upper space 114a is circulated to the first upper space 113a, and the valve 116a at the bottom of the dust chamber 110a is opened to generate a downward flow. For this reason, sedimentation of the dust 117 is promoted. The dust 117 that has settled and accumulated at the bottom of the dust chamber 110a is discharged from the bag filter 101a through the valve 116a.
On the other hand, fine dust having an average particle size of 10 μm or less has a lower sedimentation speed than coarse dust. The fine dust is collected on the outer surface of the backwash dust collecting filter cloth 112a by an air flow generated by exhausting the second upper space 114a. Therefore, the gas circulated from the second upper space 114a to the first upper space 113a is a clean gas.

The backwashing dust collecting filter cloth attracting fan 130a includes a pipe between the second upper space 114a and the backwashing dust collecting filter cloth attracting fan 130a, and between the attracting fan 102 and the bag filter 101a. The gas exhausted from the second upper space 114a may be supplied to the first upper space 113a through the flue. The gas supplied from the backwash dust collecting filter cloth attracting fan 130a to the first upper space 113a flows into the dust chamber 110a through the filter cloth 111a. By circulating the gas discharged from the second upper space 114a to the first upper space 113a, the inside of the bag filter 101a can be made to have a relatively high pressure, and an attracting fan for backwashing dust collecting filter cloth. Suction by 130a is promoted. Moreover, since the filter cloth 111a is maintained at a relatively positive pressure, it is possible to suppress the fine dust that has been washed away by floating back and floating again.
Alternatively, the gas supplied to the first upper space 113a may be a gas from outside the system such as air.

  The valves 122a, 131a, 132a, 116a are closed, and the backwashing is finished. Next, the valves 103a and 104a are opened, and dust collection by the bag filter 101a is resumed.

  Off-line backwashing of the bag filters 101b and 101c is also sequentially performed in the same process as described above.

In the first embodiment, dust that has been washed away by backwashing, particularly fine dust in a floating state, is collected by the filter cloth for collecting backwashing dust, so that sufficient time is allowed for the dust to settle. There is no need, and the time required for backwashing can be shortened. Moreover, since fine dust does not adhere to the filter cloth when dust collection is resumed, clogging of the filter cloth is less likely to occur. As a result, an increase in pressure loss is suppressed and the life of the filter cloth can be extended.
When the backwashing dust collecting filter cloth is clogged, only the backwashing dust collecting filter cloth is replaced. For this reason, maintenance becomes easy and the time required for maintenance is shortened.

In this embodiment, the nozzle 121a is installed in the position corresponding to the backwashing dust collection filter cloth 112a. For this reason, backwashing dust collection filter cloth 112a can be backwashed regularly, and the pressure loss rise of backwashing dust collection filter cloth can be controlled.
In FIG. 1, since the first upper space 113a and the second upper space 114a are connected to the backwash air source 120 by the same pipe, the backwashing of the filter cloth and the backwash dust collecting filter cloth is performed by the valve. It is carried out at the same time when 122a is opened. Alternatively, when the first upper space 113a and the second upper space 114a are connected to the backwash air source 120 by separate pipes, the backwash timing of the backwash dust collecting filter cloth is determined by the filter cloth. It can be arbitrarily set separately.

  In the dust collector 100 of the first embodiment, a preliminary charging unit may be installed in the flue between the boiler 150 and the bag filter 101.

  FIG. 2 is an example of the preliminary charging unit. 2 includes a plurality of projecting discharge electrodes 202 supported by a support 201, a flat ground electrode 203, and a high-voltage power supply 204 connected to the support 201. As shown in FIG. 2, a plurality of supports 201 and a ground electrode 203 may be provided. The tip of the discharge electrode 202 and the ground electrode 203 are opposed to each other, and the support 201 and the ground electrode 203 are arranged substantially in parallel. The combustion exhaust gas flowing in from the boiler flows through the gap between the support 201 and the ground electrode 203 as shown in FIG.

  FIG. 3 shows another example of the preliminary charging unit. 3 includes a plurality of protruding discharge electrodes 212 instructed by the support 211, a ground electrode 213 having a plurality of holes, and a high-voltage power supply 214 connected to the support 211. The ground electrode 213 is, for example, a wire mesh or a punching metal. The tip of the discharge electrode 212 and the ground electrode 213 face each other, and the support 211 and the ground electrode 213 are arranged in parallel. The flow of combustion exhaust gas from the boiler is perpendicular to the ground electrode 213, and the combustion exhaust gas flows through the hole of the ground electrode 213.

If the combustion exhaust gas flows when power is supplied to the discharge electrodes 202 and 212 from the high-voltage power supplies 204 and 214, the dust contained in the combustion exhaust gas is charged.
The charged dust flows into the bag filter 101 and is collected on the surface of the filter cloth 111. When the charged dust is collected on the surface of the filter cloth 111, fine dust tends to aggregate with coarse dust on the surface of the filter cloth 111. For this reason, the collection rate of the fine dust in the bag filter 101 is improved.
When off-line backwashing is performed, fine dust aggregates, so that fine dust floating in the dust chamber 110 during backwashing can be reduced, and the life of the backwash dust collecting filter cloth 112 can be reduced. Can be extended. Further, the agglomerated dust is easily removed from the filter cloth 111 during backwashing, and the settling speed is high. For this reason, an increase in pressure loss can be suppressed. For example, it is possible to reduce the installation area (filtration area) of the bag filter without reducing the pressure loss.

<Second Embodiment>
FIG. 4 is a schematic view of a dust collector according to the second embodiment. In the present embodiment, by increasing the flow rate of the attracting fan 302 as compared with the case of the first embodiment, the attracting fan 302 functions as an attracting fan for backwashing dust collecting filter cloth in the first embodiment. Therefore, in this embodiment, the apparatus can be further simplified.

A duct is connected to the downstream side of the induction fan 302 (the flue between the induction fan 302 and the chimney 360). The duct is connected to each flue between the valves 304a, 304b, 304c and the first upper space 313a, 313b, 313c. A flow rate adjustment valve 370 is provided in the duct.
Each flue between the valves 304a, 304b, 304c and the attracting fan 302 and the second upper space 314a, 314b, 314c are connected by a duct. Each of the ducts is provided with valves 332a, 332b, and 332c.

  In the present embodiment, the flow rate adjustment valve 370 is always open. When performing off-line backwashing of the bag filter 301a in the dust collector of FIG. 4, the valve 304a is closed and the valve 332a is opened. As a result, the second upper space 314a is exhausted by the attracting fan 302, and an airflow is generated from the dust chamber 310a through the backwashing dust collecting filter cloth 312a toward the second upper space 314a. Further, the valve 331a is opened, and the exhaust gas exhausted from the second upper space 314a is circulated to the first upper space 313a through the induction fan 302. Thereby, the inside of the bag filter 301a can be made into a relatively high pressure, and the filter cloth 311a can also be kept at a relatively positive pressure.

The valve 322a between the backwash air source 320 and the first upper space 313a is opened. Thereby, the dust deposited on the outer surface of the filter cloth 311a falls off. The dropped dust settles below the dust chamber 310a by opening the valve 316a, and fine dust with a slow sedimentation speed is collected by the backwash dust collection furnace cloth 312a.
The valves 304b and 304c are opened, and the valves 331b, 331c, 332b, and 332c are kept closed. For this reason, dust collection is continued in the bag filters 301b and 301c.

  As a modification of FIG. 4, the valve 304 is replaced with a duct (back flow line) that connects the flue between the induction fan 302 and the chimney 360 and the duct between the first upper space 313 and the valve 304. And the duct between the first upper space 313 and the valve 304, and a backflow fan may be provided between them. By doing so, backwashing can be performed even when the air flow of the attracting fan 302 is not sufficient.

<Third Embodiment>
FIG. 5 is a schematic view of a dust collector according to the third embodiment. In the present embodiment, a plurality of filter cloths 411 and a plurality of backwashing dust collecting filter cloths 412 are provided in one bag filter 401. A plurality of first upper spaces 413 and a plurality of second upper spaces 414 are provided on the upper portions of the filter cloth 411 and the backwashing dust collecting filter cloth 412. In FIG. 5, only one backwashing dust collecting filter cloth 412 is provided for one second upper space 414, but a plurality of backwashing dust collecting filter cloths may be provided.

  The backwash air source 420 is connected to the plurality of first upper spaces 413a, 413b, 413c, 413d and the plurality of second upper spaces 414a, 414b, 414c through a pipe. In the pipes in the first upper space 413 and the second upper space 414, nozzles 421 are installed at positions corresponding to the filter cloth 411 and the backwash dust collecting filter cloth 412, respectively.

Each of the second upper spaces 414 is connected to an attraction fan 430 for backwashing dust collecting filter cloth provided outside the bag filter 401. The backwashing dust collecting filter cloth 430 is connected to each duct between the first upper spaces 413a to 413d and the valves 404a to 404d.
Further, ducts connected to each of the second upper spaces 414 are coupled to the respective ducts between the first upper spaces 413a to 413d and the valves 404a to 404d. Each of the ducts is provided with valves 433a, 433b, and 433c. At the time of dust collection, the valves 433a to 443c are opened, and dust collection is performed also with the backwash dust collection filter cloth.

  FIG. 5 shows an example in which one bag filter 401 is provided, but a plurality of bag filters may be provided in parallel with the flow of combustion exhaust gas as shown in FIG.

Hereinafter, the case where the filter cloth 411c is backwashed will be described as an example.
The valve 404c is closed and dust collection by the filter cloth 411c is stopped.
The suction fan 430 for backwashing dust collecting filter cloth is activated. Next, the valves 433b and 433c are closed, and the valves 431b and 431c are opened. Thereby, the backwashing dust collection filter cloth suction fan 430 exhausts the second upper spaces 414b and 414c. For this reason, an air flow is generated from the dust chamber 410 through the backwashing dust collecting filter cloths 412b and 412c toward the second upper spaces 414b and 414c.
Since the valves 404a, 404b, 404d, the valve 433a, and the valve 403 remain open, the dust collection by the filter cloths 411a, 411b, 411d and the backwashing dust collecting filter cloth 412a is continued.

A valve 422 installed between the backwash air source 420 and the first upper space 413c is opened. Thereby, the airflow of backwashing air is jetted from the nozzle 421 to the inside of the filter cloth 413c, and the dust deposited on the outer surface of the filter cloth 413c falls off.
When the valve 416 at the bottom of the dust chamber 410 is opened, a downward flow is generated inside the dust chamber 410. Thereby, coarse dust settles to the lower part of the dust chamber 410. As shown in FIG. 5, by providing a dust settling dust vane 418 below the backwashing dust collecting filter cloth 412, the dropped dust is easily collected at the bottom of the dust chamber 410.
On the other hand, the fine dust is collected on the outer surface of the backwash dust collection filter cloth 412b, 412c adjacent to the backwashed filter cloth 411c.

  The suction fan 430 for collecting the backwashing dust is stopped, the valves 422, 431b, 431c, 432b, 432c, and 416 are closed, and the backwashing of the filter cloth 411c is completed. Next, the valve 414c is opened, and dust collection by the filter cloth 411c is resumed.

  In this embodiment, backwashing can be performed for each divided filter cloth without stopping the bag filter. Moreover, the dust dropped by the backwashing is collected by the backwashing dust collecting filter cloth adjacent to the backwashed filter cloth, and the collection by the other filter cloths 411a, 411b, and 411d is suppressed. For this reason, clogging of the filter cloth 411 due to adhesion of fine dust can be prevented.

  In this embodiment, the backwashing dust collection filter cloth 412 is regularly backwashed. In this case, the valve 433 provided in the duct connected to the second upper space 414 corresponding to the backwashing dust collecting filter cloth 412 to be backwashed is closed, and backwashing air is added to the second upper space 414. Backwash air is supplied from a source 420 through a nozzle. The backwashing dust collecting filter cloth 412 may be backwashed without closing the valve 433.

<Fourth embodiment>
FIG. 6 is a schematic view of a dust collector according to the fourth embodiment. The present embodiment is an example in which the attracting fan for backwashing dust collecting filter cloth in the third embodiment is substituted with an attracting fan as in the second embodiment. Also in this embodiment, a plurality of bag filters can be installed in parallel with the flow of the combustion exhaust gas.

Hereinafter, the case where the filter cloth 511d is backwashed will be described as an example.
In the present embodiment, the flow rate adjustment valve 570 is always open.
The valve 504d is closed and the dust collection by the filter cloth 511d is stopped. Next, the duct is connected to the duct between the first upper space 513d located above the filter cloth 511d to be backwashed and the valve 504d, and the flue between the induction fan 502 and the chimney 560. The valve 531d is opened. Further, the valve 522 between the backwash air source 520 and the first upper space 513d is opened, and backwash air is supplied to the first upper space 513d. Thereby, the dust deposited on the outer surface of the filter cloth 511d falls off. By opening the valve 516, dust settles to the bottom of the dust chamber 510.

  In the present embodiment, the valve 503, the valves 504a, 504b, and 504c, and the valves 533a, 533b, and 533c are kept open when the filter cloth 511d is backwashed. Further, the valves 531a, 531b, 531c are kept closed. For this reason, the fine dust whose sedimentation speed is slow is collected by the backwashing dust collection filter cloth 512c adjacent to the filter cloth 511d to be backwashed. Moreover, the dust collection by the filter cloth 511a, 511b, 511c which is not backwashed, and the backwash dust collection filter cloth 512a, 512b is continued.

  As a modification of FIG. 6, instead of a duct (back flow line) connecting the flue between the induction fan 502 and the chimney 560 and the duct between the first upper space 513 and the valve 504, the valve 504 is used. And the duct between the first upper space 513 and the valve 504, and a backflow fan may be provided between them. By doing so, backwashing can be performed even when the air flow of the attracting fan 502 is not sufficient.

  In the present embodiment, the valve 503, the valves 504a, 504b, and 504c, and the valves 533a, 533b, and 533c are kept open when the filter cloth 511d is backwashed. Further, the valves 531a, 531b, 531c are kept closed. For this reason, the fine dust whose sedimentation speed is slow is collected by the backwashing dust collection filter cloth 512c adjacent to the filter cloth 511d to be backwashed. Moreover, the dust collection by the filter cloth 511a, 511b, 511c which is not backwashed, and the backwash dust collection filter cloth 512a, 512b is continued.

  When the backwashing dust collecting filter cloth 512 is backwashed in the dust collector of the fourth embodiment, the duct valve 533 connected to the second upper space 514 corresponding to the backwashed filter cloth 512 is first closed. The Next, the valve between the second upper space 514 corresponding to the backwashing dust collecting filter cloth 512 to be backwashed and the backwashing air source 520 is opened. Thereby, the backwashing air is injected into the backwashing dust collecting filter cloth 512, and the dust falls off from the outer surface of the backwashing dust collecting filter cloth 512. The backwashing dust collecting filter cloth 512 may be backwashed without closing the valve 533.

  As another modification, as shown in FIG. 7, a duct connecting the flue between the valve 604 and the induction fan 602 and the second upper space 614 is provided, and the first upper space is further provided. It is good also as a structure which omitted the path | route which circulates gas. A valve 633 is installed in each duct.

Hereinafter, the case where the filter cloth 611c is backwashed will be described as an example.
The valve 604c is closed, and dust collection by the filter cloth 611c is stopped. Since the valves 604a, 604b, and 604d are opened, dust collection by the filter cloths 611a, 611b, and 611d is continued. Next, the valve 622 provided between the backwash air source 620 and the first upper space 613c is opened, and backwash air is supplied to the first upper space 613c. Thereby, the dust deposited on the outer surface of the filter cloth 611c falls off.
By opening the valve 616, coarse dust settles at the bottom of the dust chamber 610. In this modification, when the filter cloth 611c is backwashed, the duct valves 633b and 633c connected to the second upper spaces 614b and 614c of the backwash dust collecting filter cloth 612b and 612c adjacent to the filter cloth 611c are opened. It will be kept. For this reason, the fine dust with a slow sedimentation speed is collected by the backwashing dust collection filter cloth 612b, 612c.
For the backwash dust collection filter cloth 612a other than the backwash dust collection filter cloth adjacent to the backwashed filter cloth, the valve 633a is opened when the other backwash dust collection filter cloth is backwashed. Also good. By carrying out like this, the dust collection efficiency at the time of backwashing can be improved. Or valve 633a may be closed at the time of backwashing other backwashing dust collection filter cloth. By carrying out like this, it becomes possible to lengthen the lifetime of the backwashing dust collection filter cloth itself.

  In this modification, the apparatus configuration can be simplified by using the same induction fan for the exhaust system of the first upper space and the second upper space. In addition, if the induction fan exhausts the backwash air for backwashing, the bag filter interior will settle down to approximately the same pressure as during normal operation. Is not necessarily required. For this reason, an apparatus structure can be simplified more.

  In 2nd Embodiment thru | or 4th Embodiment, the preliminary | backup charge part demonstrated in 1st Embodiment may be provided in the flue between a boiler and a bag filter. By charging the dust in the combustion exhaust gas by the preliminary charging unit, the dust tends to settle during off-line backwashing.

<Fifth Embodiment>
FIG. 8 is a schematic view of a dust collector according to the fifth embodiment. Similar to the first embodiment, the dust collector 700 includes a bag filter 701 and an induction fan 702 in the flue downstream of the boiler 750. A chimney 760 is installed on the downstream side of the induction fan 702. FIG. 8 illustrates a case where three bag filters 701a, 701b, and 701c are provided. Bag filters 701a, 701b, and 701c have the same structure.

  In the bag filter 701 of the fifth embodiment, a plurality of filter cloths 711 are suspended in the dust chamber 710. An upper space 713 that is isolated from the dust chamber 710 through a filter cloth 710 is provided on the upper side of the dust chamber 710. The upper space 713 is connected to the induction fan 702 on the downstream side through the flue. Valves 704a, 704b, and 704c are provided in the flue between the upper space of each bag filter 701a, 701b, and 701c and the induction fan 702, respectively.

  Outside the bag filter 701, a backwash air source 720 connected to the upper space 713 of each bag filter 701 through a pipe is installed. A nozzle 721 is installed at a position corresponding to the filter cloth 711 in the pipe through which the backwash air flows in the upper space 713.

  Ducts are connected to the flue between the upper space of each bag filter 701a, 701b, 701c and the valve 704a, 704b, 704c, and the flue between the valve 704a, 704b, 704c and the induction fan 702, respectively. The reverse flow fans 730a, 730b, and 730c are connected. Valves 731 and 732 are installed in each duct.

  Also in the fifth embodiment, a precharge unit similar to that in the first embodiment may be installed in the flue between the boiler 750 and the bag filter 701.

In the dust collector of FIG. 8, the process of performing off-line backwashing will be described below. Here, a case where the bag filter 701a is backwashed will be described.
A valve 704a installed between the bag filter 701a and the induction fan 702 is closed. Thereby, the exhaust of the upper space 713a by the induction fan 702 is stopped.
Since the valves 704b and 704c between the bag filters 701b and 701c and the induction fan 702 are open and the backflow fans 730b and 730c are not activated, dust collection by the bag filters 701b and 701c is continued. ing.

The backflow fan 730a is activated. Valves 731a and 732a provided in a duct connecting the flue between the bag filter 701a and the induction fan 702 and the backflow fan 730a are opened. As a result, the gas discharged after the dust is removed by the bag filters 701b and 701c is supplied to the upper space 713a of the bag filter 701a. The gas flows into the dust chamber 610a through the filter cloth 711a.
Next, the valve 722a installed between the upper space 713a of the bag filter 701a and the backwash air source 720 is opened. An airflow of backwashing air is jetted from the nozzle 721a to the inside of the filter cloth 711a. Thereby, the dust deposited on the outer surface of the filter cloth 711a falls off from the filter cloth 711a.

Since the gas exhausted from the bag filters 701b and 701c is supplied to the bag filter 701a by the backflow fan 730a, the bag filter 701a is held at a higher pressure than the other bag filters. For this reason, a downward flow is generated in the dust chamber 710a of the bag filter 701a, and the gas containing the dust 717 that has fallen off from the filter cloth 711a is discharged from the bag filter 701a. Further, when the dust collection of the bag filter 701a is resumed, it is possible to prevent the dust removed during backwashing from being collected again on the filter cloth 711a. The gas containing the discharged dust 717 flows into the other bag filters 701b and 701c through the flue between the boiler 750 and the bag filter.
Also, by opening the valve 716a at the bottom of the dust chamber 710a, the downward flow is increased and the sedimentation of the dust 717 that has fallen off is promoted. Part of the dropped dust 717 is discharged from the valve 716a at the bottom of the dust chamber 710a.

  The dust transported from the bag filter 701a to the other bag filters 701b and 701c together with the gas is collected by the filter cloth of the bag filters 701b and 701c. Here, the dust conveyed to the bag filters 701b and 701c includes fine dust, but is collected by agglomerating with the dust already collected on the filter cloth.

In the present embodiment, the dust discharged from the bag filter 701a may be allowed to pass through the above-described precharge portion before flowing into the other bag filters 701b and 701c. Aggregation of the discharged dust is promoted by passing the precharged portion. By doing so, the agglomerated dust flows into the bag filters 701b and 701c and is collected by the filter cloth. For this reason, the pressure-loss fall of the filter cloth of bag filter 701b, 701c can be suppressed.
Further, the dust flowing in from the boiler 750 may become charged dust by passing through the above-described preliminary charging portion, and collide with the dust discharged from the bag filter 701a to promote dust aggregation.

  When the backflow fan 730 is stopped and the valves 722a, 731a, and 732a are closed, the backwashing is finished. Next, the valve 704a is opened, and dust collection by the bag filter 701a is resumed.

  The backwashing of the bag filters 701b and 701c is also sequentially performed in the same process as described above.

In this embodiment, downflow is generated, and dust that has fallen out by backwashing is transported to another bag filter and collected. Can be prevented from adhering again to the backwashed filter cloth. As a result, an increase in the pressure loss of the bag filter can be suppressed.
Further, the fine dust dropped off from the backwashed bag filter is aggregated and collected by the dust collected on the filter cloth of the bag filter not backwashed. Thereby, dust becomes coarse. For this reason, when other bag filters are back-washed, the sedimentation rate of dust becomes large, and the back-washing effect can be enhanced.
As a result of the above effects, it is possible to extend the life of the filter cloth.

<Sixth Embodiment>
FIG. 9 is a schematic view of a dust collector according to the sixth embodiment. In this embodiment, a common backflow fan is installed in each bag filter.
Specifically, valves 804a, 804b, and 804c are provided in the flue between the bag filters 801a, 801b, and 801c and the induction fan 802, respectively. A duct is connected to the flue between the valves 804 a, 804 b and 804 c and the induction fan 802, and is connected to the backflow fan 830. Also, ducts are connected to the flue between the valves 804a, 804b, 804c and the bag filters 801a, 801b, 801c, and are connected to the backflow fan 830, respectively. In this embodiment, the backflow fan 830 is always activated and the valve 831 is opened.

  Also in the sixth embodiment, a precharge unit similar to that in the first embodiment may be installed in the flue between the boiler 850 and the bag filter 801. Accordingly, the dust discharged from the bag filter 801a can be charged by passing the preliminary charging portion before flowing the dust into the other bag filters 801b and 801c. Further, the dust flowing in from the boiler 850 becomes charged dust by passing through the above-described precharge portion, and collides with the dust discharged from the bag filter 801a, whereby the dust aggregation can be promoted.

When off-line backwashing of the bag filter 801a is performed in the dust collector of FIG. 8, the valve 804a is closed and the valve 832a is opened. The valves 804b and 804c are opened, and the valves 832b and 832c are kept closed. As a result, the gas discharged after the dust is removed by the bag filters 801b and 801c is supplied to the upper space 813a of the bag filter 801a by the backwash fan 830.
Other processes are the same as those in the fifth embodiment.
The sixth embodiment has an advantage that the operation at the time of backwashing becomes easy and the apparatus can be simplified as compared with the fifth embodiment.

<Seventh embodiment>
FIG. 10 is a schematic view of a dust collector according to the seventh embodiment. In this embodiment, by increasing the flow rate of the induction fan 902 as compared with the case of the fifth embodiment and the sixth embodiment, the induction fan 902 functions as the backflow fan of the fifth embodiment and the sixth embodiment. Fulfill.

A duct is connected to the flue between the induction fan 902 and the chimney 960. The duct is connected to each flue between the valves 904a, 904b, 904c and the bag filters 901a, 901b, 901c. A flow rate adjusting valve 970 is provided in the duct.
In this embodiment, the flow rate adjustment valve 970 is always open. When off-line backwashing of the bag filter 901a is performed in the dust collector of FIG. 10, the valve 904a is closed and the valve 931a is opened. The valves 904b and 904c are opened, and the valves 931b and 931c are kept closed. As a result, the gas discharged after the dust is removed by the bag filters 901b and 901c is supplied to the upper space 913a of the bag filter 901a by the induction fan 902.
Other processes are the same as those in the fifth embodiment.

  Also in the seventh embodiment, a preliminary charging unit may be installed in the flue between the boiler 950 and the bag filter 901. Thus, the dust discharged from the bag filter 901a can be charged by passing the preliminary charging portion before flowing the dust into the other bag filters 901b and 901c. Further, the dust flowing in from the boiler 950 may pass through the above-described preliminary charging portion to become charged dust, collide with the dust discharged from the bag filter 901a, and promote the aggregation of the dust.

  As a modification of FIG. 10, instead of a duct (back flow line) connecting the flue between the induction fan 902 and the chimney 960 and the duct between the first upper space 913 and the valve 904, the valve 904 is used. And a duct between the first upper space 913 and the valve 904, and a backflow fan may be provided between them. By doing so, backwashing can be performed even when the air volume of the attracting fan 902 is not sufficient.

<Eighth Embodiment>
FIG. 11 is a schematic view of a dust collector according to the eighth embodiment. In this embodiment, a plurality of filter cloths 1011 are provided in one bag filter 1001. An upper space 1013 is provided above the dust chamber 1011. The upper space 1013 is separated into a plurality of spaces by partition walls.
In FIG. 11, four filter cloths are installed and the upper space is separated into four, but two or more filter cloths may be defined as one section, and the upper space may be separated corresponding to each section. For example, when four filter cloths are installed as shown in FIG. 11, two upper spaces may be provided by dividing two filter cloths (1013a and 1013b and 1013c and 1013d) into one section.

  A partition 1018 may be provided between each filter cloth 1011. The upper end of the partition 1018 is connected to a wall that separates the dust chamber 1010 and the upper space 1013. The lower end of the partition 1018 is located with a gap so that the gas in the dust chamber 1010 can flow.

The backwash air source 1020 is connected to each of the upper spaces 1013a, 1013b, 1013c, and 1013d separated through the piping.
Each of the upper spaces 1013a, 1013b, 1013c, and 1013d is connected to the induction fan 1002 by a flue. Valves 1004a, 1004b, 1004c, and 1004d are provided in the middle of the flue.

A duct is connected to the flue between the valves 1004a, 1004b, 1004c, 1004d and the induction fan 1002, and is connected to the backflow fan 1030. Valves 1031a, 1031b, 1031c, and 1031d are installed in each duct. The valves 1031a to 1031d are closed during dust collection.
A duct is connected to the flue between the upper spaces 1013a, 1013b, 1013c, 1013d and the valves 1004a, 1004b, 1004c, 1004d, and is connected to a backflow fan 1030 provided outside the bag filter 1001. Valves 1032a, 1032b, 1032c, and 1032d are installed in each duct. Valves 1032a to 1032d are closed during dust collection.

Hereinafter, the case where the filter cloth 1011d is backwashed will be described as an example.
The valve 1004d is closed, and dust collection by the filter cloth 1011d is stopped.
The backflow fan 1030 is activated. Valves 1031d and 1032d are opened. Next, the valve 1022 installed between the upper space 1013d corresponding to the filter cloth 1011d to be backwashed and the backwashing air source is opened. Thereby, the air flow of backwashing air is jetted from the nozzle 1021 to the inside of the filter cloth 1011d, and the dust accumulated on the outer surface of the filter cloth 1011d falls off.
In this embodiment, since the partition 1018 is provided, when the valve 1016 at the bottom of the dust chamber 1010 is opened, a downward flow is generated around the filter cloth 1011d. As a result, coarse dust settles down to the lower portion of the dust chamber 1010. On the other hand, fine dust is collected on the outer surfaces of the filter cloths 1011a to 1011c.

The backflow fan 1030 is stopped and the valves 1022, 1031d, 1032d, and 1016 are closed, and the backwashing of the filter cloth 1011d is completed. Next, the valve 1004d is opened, and dust collection by the filter cloth 1011d is resumed.
In this embodiment, a downward flow is generated around the backwashed filter cloth, and fine dust is collected by another filter cloth. Therefore, when dust collection with the backwashed filter cloth is resumed, the filter cloth is filtered. It is possible to prevent fine dust from being collected on the cloth surface.

<Ninth Embodiment>
FIG. 12 is a schematic view of a dust collector according to the ninth embodiment. The present embodiment is an example in which the backflow fan in the eighth embodiment is substituted with an attracting fan.

Hereinafter, the case where the filter cloth 1111d is backwashed will be described as an example.
In the present embodiment, the flow rate adjustment valve 1170 is always open.
The valve 1104d is closed and dust collection by the filter cloth 1111d is stopped.
The valve 1131d provided in the duct connecting the upper space 1113d located above the filter cloth 1111d to be backwashed and the valve 1104d and the duct connecting the induction fan 1102 and the chimney 1160 is opened. The Next, the valve 1122 between the backwash air source 1120 and the upper space 1113d is opened, and backwash air is supplied to the upper space 1113d. Thereby, the dust deposited on the outer surface of the filter cloth 1111d falls off.
Since the partition 1118 is provided in this embodiment, when the valve 1116 at the bottom of the dust chamber 1110 is opened, a downward flow is generated around the filter cloth 1111d. For this reason, coarse dust settles to the lower part of the dust chamber 1110. On the other hand, fine dust is collected on the outer surfaces of the other filter cloths 1111a to 1111c.

  Also in the present embodiment, as in the fourth embodiment, a duct (back flow line) connecting the flue between the induction fan 1102 and the chimney 1160 and the duct between the upper space 1113 and the valve 1104 is used. Thus, the flue between the valve 1104 and the induction fan 1102 and the duct between the upper space 1113 and the valve 1104 may be connected, and a backflow fan may be provided therebetween. By doing so, backwashing can be performed even when the air volume of the attracting fan 1102 is not sufficient.

  In the eighth embodiment and the ninth embodiment, the precharge portion described in the first embodiment may be provided in the flue between the boiler and the bag filter. By charging the dust in the combustion exhaust gas by the preliminary charging unit, the dust tends to settle during off-line backwashing. Furthermore, fine dust conveyed from the bag filter being backwashed to another bag filter is likely to aggregate with coarse dust.

  In addition, this invention is not limited to the removal of the dust in combustion exhaust gas demonstrated in the said embodiment, It is applied also when removing the dust in the air.

100, 300, 400, 500, 600, 700, 800, 900, 1000, 1100 Dust collector 101, 301, 401, 501, 601, 701, 801, 901, 1001, 1101 Bug filter 102, 302, 402, 502 , 602, 702, 802, 902, 1002, 1102 Induction fan 110, 310, 410, 510, 610, 710, 810, 910, 1010, 1110 Dust chamber 111, 311, 411, 511, 611, 711, 811, 911 , 1011, 1111 Filter cloth 112, 312, 412, 512, 612 Backwash dust collecting filter cloth 113, 313, 413, 513, 613 First upper space 114, 314, 414, 514, 614 Second upper space 115,315 Partition 120,320,4 0,520,620,720,820,920,1020,1120 Backwash air source 121,321,421,521,621,721,821,921,1021,1121 Nozzle 130,430 Backwash dust collecting filter cloth Induction fan 730, 830, 1030 Backflow fan 150, 350, 450, 550, 650, 750, 850, 950, 1050, 1150 Boiler 160, 360, 460, 560, 660, 760, 860, 960, 1060, 1160 Chimney 713, 813, 913, 1013, 1113 Upper space 200 Preliminary charging unit 201 Support body 202 Discharge electrode 203 Ground electrode 204 High voltage power supply 370, 570, 970, 1170 Flow rate adjustment valve

Claims (13)

A dust collector for removing dust in gas,
In the flue through which the gas circulates, in order from the upstream side, including a bug filter and an attracting fan,
The bug filter is
A dust chamber;
A filter cloth suspended in the dust chamber and collecting dust during gas treatment;
A backwashing dust collecting filter cloth that is suspended in the dust chamber and collects part of the dust that has fallen off the filter cloth during backwashing;
A first upper space provided on the filter cloth and isolated from the dust chamber through the filter cloth;
A second upper space provided on the backwashing dust collecting filter cloth, isolated from the dust chamber through the backwashing dust collecting filter cloth, and isolated from the first upper space; ,
A backwash air source for supplying backwash air is connected to the first upper space and the second upper space,
A dust collector in which an attracting fan for backwashing dust collecting filter cloth is connected to the second upper space.   The dust collector according to claim 1, wherein a plurality of the bag filters are installed.   The dust collector according to claim 1 or 2, comprising a plurality of the filter cloths and a plurality of the backwash dust collecting filter cloths in the dust chamber.   The dust collecting apparatus according to claim 1, wherein the attracting fan for backwashing dust collecting filter cloth is the attracting fan. A dust collector for removing dust in gas,
In the flue through which the combustion exhaust gas circulates, in order from the upstream side, including a plurality of bag filters and an induction fan,
Each of the plurality of bug filters
A dust chamber;
A filter cloth suspended in the dust chamber and collecting dust during gas treatment;
An upper space provided on an upper portion of the filter cloth and isolated from the dust chamber through the filter cloth;
A backwash air source for supplying backwash air is connected to the upper space,
A dust collector in which a backflow fan is connected to the upper space. A dust collector for removing dust in gas,
In the flue through which the gas circulates, in order from the upstream side, including a bug filter and an induction fan
The bug filter is
A dust chamber;
A plurality of filter cloths suspended in the dust chamber and collecting dust during gas treatment;
An upper space provided on top of the plurality of filter cloths, separated from the dust chamber through the filter cloths, and separated into a plurality of compartments by partition walls;
A backwash air source for supplying backwash air is connected to each of the compartments,
A dust collector in which a backflow fan is connected to each of the compartments.   The dust collector according to claim 5 or 6, wherein the backflow fan is the induction fan.   The dust collector according to any one of claims 1 to 7, further comprising a pre-charging unit that imparts electric charge to the dust in the gas on an upstream side of the bag filter. An operation method of the dust collector according to claim 1,
Stopping the exhaust of the first upper space by the attraction fan when backwashing the bag filter;
Supplying the backwashing air from the backwashing air source to the first upper space and applying an air flow to the inside of the filter cloth to remove dust collected on the outside of the filter cloth; ,
Discharging the gas from the second upper space, sucking the inside of the backwashing dust collecting filter cloth, and collecting the removed dust with the backwashing dust collecting filter cloth; Operation method of the dust collector provided.   The method for operating a dust collector according to claim 9, wherein gas is supplied to the first upper space in the step of collecting dust with the backwashing dust collecting filter cloth. An operation method of the dust collector according to claim 5,
Stopping the exhaust of the upper space by the attraction fan during backwashing of the one bag filter;
By supplying the backwashing air from the backwashing air source to the upper space of the backwashed bag filter and providing an air flow inside the plurality of filter cloths of the backwashed bag filter, Removing dust collected on the outside of the plurality of filter cloths;
Supplying gas from the backflow fan to the upper space;
The gas is discharged from the upper space of the other bag filter, the dust removed from the dust chamber of the bag filter to be backwashed is discharged, and conveyed to the dust chamber of the other bag filter. And a step of collecting with the filter cloth of the other bag filter. An operation method of the dust collector according to claim 6,
When the bag filter is backwashed, stopping the exhaust by the induction fan of the compartment located above the filter cloth to be backwashed;
The backwash air is supplied from the backwash air source to a compartment located above the filter cloth to be backwashed to provide an air flow inside the backwashed filter cloth. Removing dust collected outside the filter cloth,
Supplying gas from the backflow fan to the compartment located above the filter cloth to be backwashed;
A method of operating a dust collector, comprising: exhausting gas from the compartment located above the other filter cloth and collecting the dust that has been removed by the other filter cloth.   The method for operating a dust collector according to any one of claims 9, 11, and 12, further comprising a step of applying an electric charge to the dust in the gas upstream of the bag filter.

Images