JPH03154609A - Method and device for dust recovery - Google Patents

Abstract

PURPOSE:To permit an easy recovery of dusts and prevent the production of suspended dusts by a method wherein, when a dust-contg. air stream is supplied into a pressure reducing container through a pipe, a liq. dust coagulant is sprayed against the dust contg. air stream in the pipe near the opening of the pressure reducing container. CONSTITUTION:A suction conduit pipe 24 for supplying a dust contg. air stream G into a hopper 20 causes nozzles 25a and 25b near an opening of the hopper 20 to spray a two-liquid reactive coagulants A and B. The dusts in the air stream G are coagulated into a mass of a high viscosity, which is then dropped into the hopper 20 under its own weight and accumulated on the bottom part thereof. The hopper 20 is kept vacuous by evacuating through a pressure reducing conduit pipe 23 connected to a pressure reducing device. When the dust masses amount to an appropriate amt., the sucking operation is stopped to open a gate 22 at the bottom part of the hopper 20 and allow them to drop into a recovery tank 11. The gate is then closed, the sucking operation is restarted, the tank 11 is moved and an empty tank is set in place. This method permits an easy recovery of the dusts and prevents the production of suspended dusts.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a dust collection method and device that are effective, for example, when removing asbestos layers that have been applied to the walls and ceilings of buildings. .

[Conventional technology] Many existing buildings have asbestos surfaces on their walls and ceilings, which were once useful for purposes such as sound absorption, heat insulation, and dew prevention. Asbestos is a carcinogenic substance, and therefore there is an urgent need to improve asbestos surfaces in existing buildings.

There are two methods for renovating asbestos surfaces: one is to solidify and contain the asbestos layer as it is by injecting or applying resin, and the other is to completely remove the asbestos layer.

With the method of solidifying and containing asbestos, it is difficult to completely assimilate the entire asbestos layer, and it is not possible to confirm it, so there remains a risk that floating dust of unsolidified asbestos will be generated when the building is demolished.

In contrast, removing the asbestos layer is a wise method that will not leave any problems in the future.

Conventional asbestos removal methods include pulverizing the asbestos layer by jetting high-pressure water and washing it away, mechanically scraping it off with a scraper, or combining this with a vacuum suction machine. .

[Problems to be Solved by the Invention] Among the conventional asbestos removal methods, in the method of injecting high-pressure water, when the asbestos is crushed by the injected water, fine asbestos flows out with the running water.
There is a post-treatment problem in that a large amount of wastewater must be filtered.

On the other hand, with the method of mechanically scraping off the asbestos layer, if you suddenly remove the dry asbestos layer with a scraper, floating asbestos dust will scatter, so be sure to spray water etc. beforehand and then inject a solidifying liquid. The peeling process begins, but the injection process itself and solidification take time.
Furthermore, even with these preparations, it was not possible to completely prevent the generation of asbestos floating dust.

Furthermore, no matter which method is used, in order to prevent the asbestos being removed from scattering and to be recovered, it is necessary to cover the floors and windows of the construction site with airtight sheets for sufficient curing, and workers are also required to wear respiratory protective equipment and It was necessary to have the workers wear protective clothing and pay sufficient attention to safety management in the workplace and protection of the external environment.

The present inventor has proposed an asbestos removal method and apparatus for solving the above-mentioned problems of the prior art in Japanese Patent Application No. 63-253874. According to this, fluid is sprayed in a curtain shape to surround the periphery of a limited area on the asbestos surface to be removed, which has been applied to the ceiling of an existing building. It is isolated from the surrounding area with a fluid jet curtain. The isolated space inside the fluid jet curtain is maintained under negative pressure from the outside, and the asbestos layer in the area is stripped in the isolated space. In this case, the tip of the fluid jet curtain is always in contact with the asbestos surface on its entire circumference, and since the inner isolated space is under negative pressure, the jetted fluid is always drawn down into the isolated space without flowing outward. After the peeled asbestos is crushed within the isolated space, it is collected outside the isolated space along with the recovery of the injection fluid by negative pressure suction. In this case, if the recovery fluid is a liquid, it will provide appropriate moisture to the crushed asbestos, making it possible to recover asbestos with less floating dust.

Furthermore, even if it is a gas, the generation of floating dust can be suppressed by spraying the liquid onto the crushed asbestos.

The above-mentioned steps are performed on an asbestos surface of a required size while moving the isolated space.

In this method, asbestos is peeled off and crushed in an isolated space surrounded by a fluid jet curtain, and the jetted fluid is recovered and the crushed asbestos is collected by vacuum suction.
Water and asbestos do not fly away, and collection and processing can be done using existing filter-equipped vacuum suction equipment. Therefore, curing work such as sealing the site before construction can be significantly simplified compared to conventional methods, and cleaning work to be performed after construction can be made much easier. Best of all, the removal work can be started immediately without injecting a chemical into the asbestos layer in advance, and the asbestos layer can be removed continuously in strips, making it extremely efficient.

The present invention further enhances such a system, and its purpose is to provide a method and device that easily enables dust collection with almost no dust scattering on the vacuum suction device side.

Although the present invention is particularly effective in collecting asbestos dust, the dust to be collected is not limited to this.

[Means for Solving the Problems] According to the present invention, for example, dust that dries and is generated while being conveyed through a conduit to the reduced pressure suction device can be efficiently agglomerated or agglomerated by spraying liquid for aggregation in the closed space. It is condensed and collected.

That is, in the dust collection method according to the invention described in claim 1, when a dust-containing airflow is sucked into a reduced pressure container to separate and collect dust from the inside of the container, the dust is collected on the upstream side of the dust suction port into the container. A liquid for agglomerating powder B is injected into a dust-containing air stream.

Further, in the dust collection method according to the second aspect of the invention, as the liquid for dust aggregation, for example, water or a liquid to which a surfactant is added is injected to moisten the dust.

Further, in the dust collection method according to the third aspect of the invention, as the dust aggregation liquid, a two-component polymerization-reactive liquid is injected, for example, from separate nozzles to condense the dust.

Further, in the dust collection device according to the invention described in claim 4, there is provided a hopper connected to a reduced pressure suction source via a filter, a dust-containing airflow introduction pipe connected to the reduced pressure internal space of the hopper, and the introduction pipe. A dust agglomerated liquid injection nozzle provided in the vicinity of the opening of the passageway to the hopper, and a collection container that receives the agglomerated dust separated from the air flow in the hopper from the lower opening of the hopper. be.

Further, in the PII dust collection device according to the invention set forth in claim 5, in addition to the structure set forth in claim 4, the lower opening of the hopper is configured to be openable and closable with respect to the collection container.

Furthermore, in the dust collection device according to the invention set forth in claim 6, in addition to the structure set forth in claim 4, the collection container is provided with means for adsorbing a sealed collection bag to the inner surface of the container in a lined state. It is something.

[Function] In the present invention, for a dust-containing airflow introduced into a vacuum container (hopper) before a filter of a vacuum suction device for collecting dust, the airflow is removed near the opening of a conduit into the container. A flocculating liquid is injected into the vacuum container, and therefore, when the dust enters the vacuum container, it becomes agglomerated by the injected liquid, and immediately falls and accumulates in the collection container at the bottom of the container due to its own weight. Therefore, the filter is less likely to be clogged, and powder strings are hardly blown away. The aggregated dust that has accumulated in the collection container is transported to another location by stopping vacuum suction as appropriate.
be disposed of.

The liquid for dust aggregation used in the present invention can be selected from various types depending on the physical properties of the dust to be collected, but it is preferably a liquid that can be easily post-treated, such as water, water with a surfactant added, or A one-component reactive coagulant is used. In addition, the injection position is set before the flow path expands in the vacuum container, that is, near the opening of the introduction pipe into the vacuum container, so that the dust is sufficiently moistened when entering the vacuum container (hopper). However, when a reactive condensate is injected, it is determined at an appropriate distance within the conduit upstream from the opening, taking into consideration the time required for the reaction.

The inside of the collection container is usually lined with a collection bag that can be closed and sealed, and the collected dust is deposited therein. The lower opening of the reduced pressure container is closed during vacuum suction operation, and during recovery, the lower opening of the reduced pressure container is opened after stopping vacuum suction, and the dust accumulated in the reduced pressure container is removed from the collection container. let it fall. Alternatively, the lower opening of the reduced pressure container may be directly connected to the upper opening of the collection container, and in this case, during the reduced pressure suction operation, the lining bag inside the collection container is flipped upward by the reduced pressure airflow for suctioning the dust airflow. A suitable means such as a vacuum pump is attached to keep the pressure between the inner surface of the collection container and the outer surface of the lining bag lower than that inside the bag so that the inner surface of the collection container does not rise.

In order to understand the specific features of the present invention, one embodiment of the present invention will be described below with reference to the drawings.

[Embodiment] FIG. 1 schematically shows a dust collection device according to a first embodiment of the present invention with a portion cut away. In FIG. 1, the main parts of the device are mounted on a trolley 10 and are movable. The lower part of the trolley 10 is a storage space 12 for a collection tank 11 that can be taken in and taken out, and the floor plate 1 of the trolley
A collection tank lifting mechanism 14 is provided on the lever 1.
5, the recovery tank 11 can be raised and lowered. That is, when the elevating mechanism 14 lowers the recovery tank 11, the recovery tank 11 can be pulled out from the trolley 10 in the direction of arrow A, whereas when the lifting mechanism 14 raises it, the upper edge of the recovery tank +1 can be pulled out from the trolley 10. It is designed to be tightly pressed against the top plate 16, and for this purpose, a backing 17 is attached to the top plate 16 of the truck, which is in close contact with the upper edge of the tank around the entire circumference.

A duct 18 is provided on the top plate 16 of the truck, and a hopper 20 is attached to the upper part of the duct 18 via a gate 22 that can be opened and closed by a lever 21. The interior of the hopper 20 of this truck upper structure is brought into a reduced pressure state by a vacuum conduit 23 connected to a suction port of a vacuum suction device (not shown), and powder is sucked in through a suction conduit 24 opening in the hopper peripheral wall.

The opening of the vacuum conduit 23 in the hopper is surrounded by a filter (not shown). Further, the suction conduit 24 has spray nozzles 25a and 25b arranged side by side immediately upstream of its opening to the hopper 20.
A is supplied with a liquid A from an external chemical supply source (not shown), and a liquid B is similarly supplied with an appropriate pressure to the nozzle 25b. In this case, the A and B liquids are known two-component reactive coagulants that have a relatively low viscosity when they are alone, but when they come into contact, they undergo a polymerization reaction and become highly viscous or solidify. Other liquids may be used depending on the physical properties of the dust to be treated.

Now, in the dust collection work using the device configured as described above, the collection tank 11 is set on the trolley 10 and the lifting mechanism 14 is
The tank 11 is placed in the raised position so that the upper edge of the tank is pressed against the gasket 17 of the top plate 16, and the gate 22 is closed and the vacuum suction device is activated to vacuum the inside of the upper hopper 20. At the same time, dust is sucked in from the conduit 24. At this time, the nozzles 25a and 25b
Liquids A and B for condensation are injected into the conduit 24 in a spray form, and the injection pressure and flow rate are adjusted so that each liquid is evenly sprayed onto the dust-containing airflow that is being sucked in. At this time, the suctioned dust is sprayed with condensed liquid before the opening to the hopper 20 and coagulates, and is transported into the hopper 20 as a lump having an appropriate viscosity. When reaching the opening to the hopper 20, the mass overcomes the suction airflow due to its own weight, falls, and is deposited in the lower part of the hopper 20. When this accumulation reaches an appropriate amount, the suction operation is stopped, the gate 22 is opened by the lever 21, the accumulation in the hopper 20 is transferred to the collection tank 11 via the duct 18, and then the gate 22 is closed again and the suction is sucked. Resume operation.

The deposits transferred into the recovery tank 11 can be transferred to a predetermined collection point by removing the recovery tank 11 from the trolley 10 by processing the lifting mechanism 14. In this case, if a sealable bag made of synthetic resin is placed inside the collection tank 11 in advance, handling of the collected dust will be easy. It goes without saying that the recovery tank must be set up again.

FIG. 2 shows a dust collection device according to a second embodiment,
In this device as well, the main parts of the device are mounted on a trolley 30, and the lower part of the movable trolley 30 serves as a storage space 32 for a recovery tank 31 that can be taken in and out. A tank elevating mechanism 34 is provided, and the collection tank 31 can be raised and lowered by operating a lever 35. That is, when the lifting mechanism 34 lowers the recovery tank 31, the recovery tank 31 moves in the direction of arrow A.
When the recovery tank 31 is raised, the upper edge of the recovery tank 31 is tightly pressed against the truck top plate 36. For this purpose, the top edge of the tank 36 is A backing 37 is attached that is in close contact with the entire circumference.

The recovery tank 31 has a large opening plate 31 forming a double bottom at the bottom.
a, and the lower surface portion of the perforated plate 31a is connected to the connection boat 31.
It is connected to a vacuum pump (not shown) via a vacuum break valve 50 connected to b. A synthetic resin sealed bag 39 is lined inside the recovery tank above the perforated plate 31a, and the rim of the bag 39 protrudes outside from the opening edge of the recovery tank 11. It is sealed by a backing 37. A hopper 40 is attached directly to the truck top plate 36, and the lower part of the hopper 40 is directly opened to the central opening 38 of the truck top plate 36.

The inside of the hopper 40 of this truck upper structure is reduced in pressure by a vacuum conduit 43 connected to a suction port of a vacuum suction device (not shown), and dust is sucked in through a suction conduit 44 that opens on the hopper peripheral wall. There is not much difference from the example shown in FIG. 1 above.

Further, the opening in the hopper of the decompression conduit 43 is surrounded by a filter (not shown).

Spray nozzles 45a and 45b are arranged side by side in the suction conduit 44 immediately upstream of its opening to the hopper 40, and surfactant is added to these nozzles 45a and 45b from an external liquid source (not shown). The aqueous solution is supplied at an appropriate pressure.

The operation of the apparatus shown in FIG. 2 begins with, as a preparatory step, covering the recovery tank 31 with a bag 39 and operating the valve 31b connected to the boat 31b to reduce the pressure in the space below the perforated plate 31a. This pressure reduction is to prevent the bag body 39 from turning up when the recovery tank 31 is set on the trolley 31 and the pressure of air taken into the hopper 40 is reduced from the conduit 43. Therefore, the bag 39 is kept stuck to the inner surface of the collection tank 30 while the inside of the hopper 40 is depressurized and the dust-containing air flow from the conduit 44 is separated. Therefore, the agglomerated dust falling from the tip of the conduit 43 in the hopper 40 is deposited in the lining bag 39 of the collection tank 30 as it is. The amount of dust accumulated in the recovery tank 30 can be confirmed using a suitable weight scale, and when the amount reaches the appropriate level, the vacuum suction in the hopper 40 is stopped and the recovery tank 30 is removed in the same manner as described above, and the dust is removed from the bag. It can be recovered while housed in the body 39.

Figure 1 [Effects of the Invention] As described above, according to the present invention, the generation of floating dust can be effectively prevented when collecting various types of dust including asbestos, and the handling of the collected dust can also be improved. There is no risk of floating dust.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an apparatus configuration according to a first embodiment of the present invention, and FIG. 2 is a schematic diagram showing an apparatus configuration according to a second embodiment of the invention. (Explanation of symbols of main parts) 10.30: Trolley, 11, 31: Recovery tank, 14, 3
4: Lifting mechanism, 20, 40: Hopper, 22: Opening/closing gate, 23, 43: Decompression conduit, 24.44: Suction conduit, 25
a, 25b, 45a, 45b nis spray nozzle.

Claims (1)

[Scope of Claims] 1. In a method for sucking a dust-containing airflow into a reduced-pressure container through a pipe line and separating and recovering dust from the airflow in the container, the A dust collection method characterized by injecting a liquid for dust coagulation into a dust-containing air stream. 2. The dust collection method according to claim 1, characterized in that a liquid that moistens the dust is injected as the dust coagulation liquid. 3. The dust collection method according to claim 1, characterized in that a two-part polymerization-reactive liquid is injected as the dust aggregation liquid. 4. A hopper connected to a reduced pressure suction source via a filter, a dust-containing airflow introduction pipe connected to the reduced pressure internal space of the hopper, and a pipe provided near the opening of the introduction pipe to the hopper. A dust recovery device comprising: a dust aggregation liquid injection nozzle; and a recovery container that receives the agglomerated dust separated from the airflow in the hopper from a lower opening of the hopper. 5. The dust collection device according to claim 4, wherein the lower opening of the hopper is configured to be openable and closable with respect to the collection container. 6. The dust collection device according to claim 4, wherein the collection container is provided with means for adsorbing a sealed collection bag on its inner surface in a lined state.