JP3605157B2 - Dust collection member - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a dust collecting member which can be used for removing dust or carbon in a gas stream, and more particularly to a method for removing oil mist and oil vapor from a gas stream containing fine oil particles (oil mist) and oil vapor. The present invention relates to an effective dust collecting member.
[0002]
[Prior art]
For example, in a kitchen of a hotel or a restaurant, a large amount of oil is generated in the form of fine particles (mist) or vapor in a cooking process. Exhausting such gas containing oil mist or oil vapor (hereinafter referred to as “oil-containing gas”) as it is is a cause of air pollution, and the oil adhering to the exhaust duct is ignited, causing a fire. There is also a danger of producing. For this reason, it is necessary to remove the oil content before the oil-containing gas is discharged to the outside, and various apparatuses have been proposed and are currently used.
[0003]
[Problems to be solved by the invention]
Among conventional oil removal devices of this type, for example, a device using a filter filled with an adsorbent such as activated carbon is provided as a device for removing oil vapor. Although this device has a relatively high oil vapor removal efficiency, the removal rate of the oil mist is so low that it is not suitable for gas in which the oil mist coexists.
[0004]
On the other hand, the oil mist is removed mainly by an inertial collision method. This method is particularly effective when the oil particles are large, but has a problem that the collection efficiency is reduced when the oil particles are fine. As means for effectively performing an inertial collision, a mesh screen having a large number of openings formed at an inclination angle of a predetermined angle (for example, 30 to 60 degrees) with respect to the passage direction of the oil-containing gas is arranged, and the mesh screen is provided. (Japanese Patent Application No. 58-27672) has been proposed in which a plurality of mesh screens are arranged so that the openings of the respective screens are angularly displaced in the plane direction by 90 degrees.
[0005]
According to the above proposed configuration, since the openings are displaced by 90 degrees each other, the oil-containing gas passing through the openings of each screen forms a swirling flow, and effective collection of dust or oil by the inertial collision method is expected. Is done. However, in order to exhibit such a collecting effect, it is necessary to stack and arrange about 10 mesh screens, and in some cases, about 20 mesh screens, and the pressure loss of the fluid passing through these screens becomes large, and There is a concern that the running cost of the apparatus will increase, such as by increasing the capacity of the apparatus. Further, in the inertial collision system including the apparatus, it is impossible to efficiently separate and collect oil vapor having a small difference in mass as compared with the carrier fluid, no matter how high the collection efficiency.
[0006]
[Means for Solving the Problems]
The present invention is a member for dust collection having a plurality of perforated screens formed with a number of openings, each opening of the perforated screen is formed obliquely at a predetermined angle with respect to the flow direction of the fluid, and Each of the adjacent porous screens is arranged by being turned 180 degrees so that the opposing surface forms the front and back, thereby forming a porous screen group as a whole, and a filter of a filtration type is arranged behind the porous screen group. The filtration type filter is a dust collecting member characterized in that, in a region in front of the filter, a pressure loss in a region near a fluid generation source is reduced more than in other regions .
[0007]
[Action]
The fluid that has flowed into the first perforated screen becomes, for example, a downward flow at an angle corresponding to the inclination angle of each opening, and in the next perforated screen in which the front and back are arranged in reverse, the descending flow is reversed and the inclination angle of the opening is reduced. And the upward flow along. Thus, each time the fluid passes through each porous screen, the fluid repeatedly descends and rises, and most of the contained trapping objects, for example, oil mist, are trapped by inertial collision, and a part of the oil vapor is also collected by agglomeration. Gathered. Further, the fluid that has exited the group of porous screens passes through a filtration filter having fine through-holes, thereby collecting oil vapor or the like that is difficult to collect by inertial collision.
[0008]
Furthermore, since the pressure loss in the region of the portion close to the source of fluid it is configured to be lower than other regions in the area in front of the filtration type filter Waso, fluid from the portion close to the source of fluid Before the fluid is dispersed, the fluid is sucked by the filter, thereby efficiently collecting oil vapor and the like in the fluid.
[0009]
【Example】
Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings.
[0010]
FIG. 1 is a diagram showing an example of a porous screen used in the present invention, and FIG. 2 shows a configuration example of a dust collecting member using the porous screen.
[0011]
First, the configuration of the porous screen will be described with reference to FIG. The arrow 1 indicates the entire porous screen, and the porous screen 1 is formed of a metal material such as SUS304 stainless steel, aluminum or nickel. However, being formed of a metal material is not an indispensable requirement for forming a porous screen, and in addition to these metal materials, for example, it can be formed of plastics or ceramics. An example will be described.
[0012]
Reference numeral 2 denotes an opening, and as the name implies, the porous screen 1 is formed by connecting a large number of openings 2 in series. For example, as a forming method, a structure in which a number of cuts (slits) are formed in a metal plate in advance and the cut portion is opened by pulling the metal plate in a predetermined direction to form an opening, that is, a structure called expanded metal A method or the like is used. Each opening 2 opens obliquely at a predetermined angle α with respect to the flow direction of the oil-containing gas G. It is effective that the angle α is such that the oil contained when the oil-containing gas G flows into the opening is separated by inertia, and that the flow does not become turbulent but maintains almost laminar flow. From these points, the inventors have conducted a test and concluded that α is suitably between 25 ° and 70 °.
[0013]
FIG. 2 shows a configuration example of a dust collecting member using the porous screen 1 shown in FIG. 1a shows the porous screen 1 shown in FIG. 1 arranged in the same state as the arrangement shown in FIG. 1, that is, a state in which each opening 2 is opened obliquely at an angle α, and 1b shows this porous screen 180 It is shown inverted, that is, placed upside down. Therefore, since the opening 2 of the porous screen 1b faces downward at an angle α, the opening angle of the opening of the porous screen 1b with respect to the oil-containing gas G will be indicated by −α hereinafter. In order to avoid misunderstanding in the following description, the opening 2 of the porous screen 1a is 2a, and the opening 2 of the porous screen 1b is 2b. Although only two porous screens 1 are arranged in the configuration shown in the figure, three or more porous screens 1 can be arranged. In this case, the adjacent porous screens 1 are arranged so as to be inverted by 180 degrees from each other.
[0014]
Next, reference numeral 3 denotes a filter (hereinafter simply referred to as a "filter") of a filtration and dust collection type disposed behind each of the porous screens 1. The filter 3 collects oil mist fine particles and oil vapor that could not be collected by the porous screens 1a and 1b by a filtration method. As a constituent material of the screen 3, a porous material made of a ceramic porous material or a metal (eg, a nickel-based metal) material commonly called a metal foam is effective. This metal foam or ceramic porous body is effective because it can be reused many times by removing the deposits. However, since most of the oil is removed in the porous screen portion, the amount of oil adhering to the filter 3 is not so large.
[0015]
In the dust collecting member having the above-described configuration, the oil-containing gas G is sucked by the induction type blower (IDF / not shown) disposed downstream of the filter 3 and travels toward the first porous screen 1a (see FIG. 2). . In this case, the IDF is operated such that the flow rate of the oil-containing gas G into the first porous screen 1a is about 0.5 to 2.0 m / sec. Since the oil-containing gas G that has reached the first porous screen 1a has the openings 1a opened obliquely at a predetermined angle α, the oil-containing gas G collides with the opening wall surface and causes the contained oil mist to adhere to the opening wall surface while descending the flow G1. To form The oil vapor contained also partially condenses due to the collision and adheres together with the mist, and the adhered oil flows down along the porous screen by its own weight and is collected in an oil reservoir (not shown).
[0016]
On the other hand, the oil-containing gas G that has exited the first porous screen 1b then flows into the opening 2b of the second porous screen 1b that opens with -α, and the downward flow G1 turns into an upward flow G2. At the time of this reversal, most of the oil mist that has not been collected in the first porous screen 1b is sorted and removed by inertia (indicated by a broken line arrow in the figure). Further, the oil-containing gas G that has turned into the upward flow G2 is further subjected to the same inertial collision method as that in the first porous screen 1a, so that the oil mist is further removed and the oil vapor is condensed on the opening wall surface and removed. The oil-containing gas G repeatedly rises and falls because the porous screens 1 are arranged 180 degrees inverted, during which time oil collection by collision, aggregation of oil vapor, and oil removal by inertia at the time of fluid inversion are repeated. As described above, the flow path of the oil-containing gas G is rapidly changed between the adjacent porous screens, so that the efficiency of removing oil from one porous screen is high. Therefore, it is possible to reduce the number of perforated screens and also to efficiently remove oil, thereby greatly reducing the pressure loss of the entire apparatus. Therefore, the number of perforated screens required for realizing an oil collection rate of 90%, including the collection by the filter 3 described later, is extremely small, ie, two to three. By the way, it is difficult to set the trapping efficiency to 90% in the conventional device itself, and even if it can be achieved, it is anticipated that the number of screens to be installed will be 10 or more. Running costs also increase considerably.
[0017]
As described above, in each of the porous screens 1a and 1b, most of the oil contained in the oil-containing gas G is removed, but fine oil particles in the oil mist and a part of the similar fine oil particles due to the condensation of oil vapor are partially removed. 2 perforated screen 1b. Filter 3 , a filter of the filtration type, is arranged to filter and trap such particles, where most of the remaining oil is removed. In this filter portion, naturally, the oil vapor colliding with the portion other than the small hole portion is aggregated and collected.
[0018]
FIG. 3 shows a configuration in which the pressure loss distribution with respect to the front of the dust collecting member is changed to increase the efficiency of suction of the oil-containing gas as the whole dust collecting member.
[0019]
In this configuration , the filter 3 is formed such that the thickness of the cross section thereof decreases toward the lower portion, so that the distribution of the pressure loss of the filter 3 changes. More specifically, it is configured such that the pressure loss at the time of passage of the gas decreases toward the lower side of the filter 3. Accordingly, the entire dust collecting member including the first and second porous screens 1a and 1b is configured such that the pressure loss at the time of passage of a fluid (gas) decreases toward the lower side of the member at the front portion thereof. become.
[0020]
With the above-described configuration, the dust collecting member has a functional characteristic that the amount of fluid suction increases in the vertical direction of the dust collecting member downward. For this reason, for example, in a state where the oil-containing gas G rises from the lower side of the dust collecting member, the oil-containing gas G is immediately sucked from the lower portion when the oil-containing gas G rises to the position of the dust collecting member. The contained gas G is efficiently sucked into the dust collecting member before being dispersed. In the illustrated configuration, the pressure loss distribution is changed by changing the thickness of the filter 3. However, for example, the thickness of the filter 3 may be uniform, and the distribution of the aperture ratio in the filter plane may be changed. It is of course possible to change the distribution of the pressure loss by changing it, or by changing both the cross-sectional thickness and the distribution of the opening ratio.
[0021]
Next, FIGS. 4A and 4B schematically show the arrangement of the openings 2 in the porous screen 1. First, in the configuration of (A), each opening 2 has a substantially rhombic shape in front of the opening, and the openings are obliquely connected to each other by making each side of the rhombus a common wall surface. . On the other hand, in the configuration of FIG. 3B, the openings 2 are arranged so as to be aligned in a line in both the horizontal direction and the vertical direction. Either of the configurations (A) and (B) may be used for removing non-liquid fine substances, that is, solid dust such as fine sand particles and fiber waste. On the other hand, when an object to be removed such as an oil mist or oil vapor, such as an oil-containing gas G, is a liquid or a substance whose liquid has changed, the configuration of (A) is more preferable. That is, in the configuration shown in FIG. 2A, since the openings 2 are positioned obliquely, the oil adhering to the walls of these openings can flow obliquely down the end of the common wall surface as indicated by the arrow, and the oil is collected. However, it becomes easier than the configuration of FIG.
[0022]
FIG. 5 shows still another configuration example .
[0023]
In the drawing, reference numeral 4 denotes a filter used in the present embodiment, and the configuration and forming material thereof are the same as those in the above-described respective configuration examples. The illustrated filter 4 is formed unevenly along the outlet of the opening 2b of the porous screen 1b. By being formed in this way, first, the surface area of the filter 4 can be set larger than the front area through which the gas passes. In this configuration, when the amount of deposits on the filter 4 is small, the upward flow G2 of the oil-containing gas G that has exited each opening 2b of the porous screen 1b passes through a surface 4a of the filter 4 that is substantially orthogonal to the upward flow G2. . In this way, at the initial stage, oil adheres around the orthogonal surface 4a of the filter 4, and the resistance of the orthogonal surface 4a gradually increases. In response to the increase in the resistance, a part of the upward flow G2 flows into a parallel surface 4b substantially parallel to the upward flow G2 as shown by a broken line. At this time, the upward flow G2 rapidly changes the flow path as indicated by the broken line, so that the pressure loss of the filter 4 as a whole increases to some extent, but an increase in the oil collection rate due to inertia is expected.
[0024]
FIG. 6 is a diagram showing a comparative example of the performance of the dust collecting member according to the present invention and a conventional dust collecting member. In the drawing, (a) shown by a solid line shows the dust collecting member of the configuration according to the present invention (the configuration shown in FIG. 2), (b) shown by the dotted line shows the configuration of only the filtration type filter, and is shown by the one-dot chain line. (C) shows the configuration of the porous screen alone.
[0025]
First, in FIG. 7A, it can be seen that in the configuration (b) including only the filtration type filter, the pressure loss increases significantly in proportion to the increase in the amount of collected oil. On the other hand, in the configuration (c) of the porous screen alone, the increase in the pressure loss is suppressed to a small amount, and the increase in the pressure loss in the configuration (a) of the present invention is also reduced to the configuration (c) of the porous screen alone. It can be seen that it is suppressed to almost the same extent.
[0026]
On the other hand, in the diagram (B), when the amount of collected oil increases with the elapse of time, the amount of oil (oil holding amount) held by the filter in the configuration (b) including only the filtration type filter increases, while the porous screen increases. In the configuration (c) alone, the oil holding amount does not increase much. That is, the configuration (b) using only the filtration type filter is considerably inferior in terms of removing the collected oil, and this causes the pressure loss in FIG. Although the configuration (a) of the present invention is not as large as the configuration (c) of the porous screen alone, the amount of retained oil can be significantly reduced as compared with the configuration (b) using only a filtration filter.
[0027]
From the above points, in the configuration of the present invention, clogging hardly occurs even when oil is collected, and since the amount of retained oil after collection is small, the risk of ignition or the like is small and the safety is high. Further, it is possible to reduce the cost for cleaning the filter.
[0028]
Next, in FIGS. 6 (C) and 6 (D), in the configuration (c) of the porous screen alone, it is necessary to set the passing wind speed to be high in order to enhance the oil removal performance [see FIG. 6 (D)]. The degree of increase in the pressure loss corresponding to the increase in the pressure is large (see FIG. (C)), and it is necessary to set the capacity of the blower large. On the other hand, in the configuration (a) of the present invention, the oil removal performance hardly decreases as shown in FIG. It can be set to a low speed, so that operation with a low pressure loss is possible as shown in FIG. Further, even when it is necessary to increase the passing wind speed, for example, by discharging a large amount of oil smoke, the increase in pressure loss can be suppressed low.
[0029]
Including the above performance comparison, the configuration of the present invention has been described by taking as an example the case where the fluid containing the trapping target is an oil-containing gas, but is effective only for the oil-containing gas containing oil as well as the dust-collecting member. It is easily understood by those skilled in the art that the present invention is widely effective for fluids containing various dusts, whether solid or liquid.
[0030]
【The invention's effect】
According to the present invention, a plurality of perforated screens are arranged and turned 180 degrees so that the front and back faces each other, that is, the perforated screens are disposed so that they are turned upside down. When passing, it passes like a wave up and down. For this reason, the efficiency of inertia / collision dust collection is high, and therefore, the efficiency of collecting objects in one porous screen is high. Further, a filter for mainly filtering and collecting dust is provided behind the porous screen for inertia / collision dust collection. Dust that is difficult to collect by the inertia / collision dust collection method can be finally collected with high efficiency, and the filter of the filtration and dust collection type is located near the source of fluid in the area in front of the filter. Since the pressure loss in the partial area is configured to be lower than that in the other areas, the target fluid can be sucked into the apparatus before diffusing, thereby achieving extremely high dust collection efficiency as a whole apparatus. I can do it.
[Brief description of the drawings]
FIG. 1 is a partial perspective view of a perforated screen used in the present invention.
FIG. 2 is a partial sectional view of a dust collecting member showing a configuration example of the present invention.
3 is a cross-sectional schematic view of the present invention the dust collecting member showing an implementation example.
FIG. 4A is a schematic front view of a porous screen showing an example of an arrangement state of openings in a porous screen, and FIG. 4B is a schematic front view of a porous screen showing another arrangement state.
FIG. 5 is a partial sectional view of a dust collecting member showing another configuration example of the present invention.
FIG. 6 is a diagram for comparing the performance of the configuration of the present invention with another conventional configuration, wherein (A) is a diagram showing the relationship between the amount of collected oil and pressure loss, and (B) is a diagram. Diagram showing the relationship between the amount of collected oil and the amount of collected oil, (C) shows the relationship between the passing wind speed and pressure loss, and (D) shows the relationship between the passing wind speed and the oil removal performance. FIG.
[Explanation of symbols]
Reference Signs List 1 perforated screen 1a first perforated screen 1b second perforated screen 2 opening 2a first perforated screen opening 2b second perforated screen opening 3 (filtration type) filter 4 filter (concave and convex)

Claims (3)

A dust collecting member having a plurality of perforated screens having a plurality of openings formed therein, each opening of the perforated screen being formed obliquely at a predetermined angle with respect to the flow direction of the fluid, and each adjacent perforated screen being forms a whole as the porous screen group by the opposing surface is disposed inverted 180 degrees to form the front and the back, in the dust collecting member filtration type filter is disposed behind of the perforated screen group, the filtration The dust collecting member is characterized in that the pressure filter is configured such that a pressure loss in a region near a fluid generation source in a region in front of the filter is reduced as compared with other regions . The filtration type filter is configured such that its cross-sectional thickness decreases toward a portion near the source of the fluid, so that a pressure loss in a region near the source of the fluid is lower than in other regions. dust collecting member according to claim 1, characterized in that it is configured to be. In the filtration type filter, by setting the opening ratio in the filter plane larger toward a portion closer to the source of the fluid, the pressure loss in a portion near the source of the fluid is reduced more than in other regions. The dust collecting member according to claim 1, wherein the dust collecting member is configured as described above.

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