JP2010155194A - Filter unit having blowback function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter unit with a blowback function which has a simple and compact structure and is capable of removing dust adhered to the filter element efficiently. <P>SOLUTION: In a container containing a filter 5 purifying a sample gas and divided into a primary space 4 and a secondary space 6 by the filter 5, a sample introducing portion 1 introducing a sample gas into the primary space 4, a purified gas delivering portion 2 delivering, through the secondary space 6, the sample gas having passed through the filter 5 as a purified gas, a blowback gas introducing portion 3 introducing a blowback gas into the secondary space 6 and an expanded opening 9 expanded gradually from the purified gas delivering portion 2 are disposed. The direction in which the blowback gas is introduced from the blowback gas introducing portion 3 has a specified inclination angle with respect to the inside surface 9a of the container, and the blowback gas is discharged toward the filter 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a filter unit having a blowback function, and more particularly, to a filter unit having a blowback function for supplying a cleaned gas by removing dust in a sample gas.

  In the measurement of specific components in the sample gas from fixed exhaust sources such as combustion boilers and mobile exhaust sources such as automobiles or various processes, dust in the sample gas is removed using a filter and a dehumidifier is installed. A more accurate measurement can be performed by introducing the sample gas into the measurement unit in a clean state by a predetermined process such as removing moisture by using the sample gas. However, when clogging occurs due to dust accumulated in the filter with long-term use, the sample exhaust resistance increases, and the sample gas flow path is corroded or contaminated by adhesion of moisture or acidic substances to the dust. Therefore, it is necessary to periodically regenerate the filter so that these can be prevented and measurement can be performed under stable conditions for a long period of time.

  For example, as shown in FIG. 10A, the filter of the particulate collection and purification device 101 that can be appropriately cleaned without removing the filter 112 of the particulate collection and purification device 101 disposed in the exhaust passage 104. 112 cleaning methods have been proposed. Specifically, it includes a cylindrical container 121 disposed in the exhaust passage 104 and a filter 112 that is housed in the container 121 and collects particulates in the exhaust gas. A plurality of nozzles 122 that open toward the downstream end face of the filter 112 and open at the other end to the outside of the container 121 are provided, and backwashing is performed by blowing high-pressure air from each nozzle 122 toward the downstream end face of the filter when the filter 112 is cleaned. Thus, the fine particles accumulated in the filter 112 are blown away to the upstream side of the filter, and the blown-off fine particles are collected. As shown in FIG. 10B, a plurality of, for example, four nozzles 122 are arranged at equal intervals in the circumferential direction (see, for example, Patent Document 1).

  Further, as shown in FIG. 11A, a particulate filter backwashing regeneration device that can efficiently perform backwashing regeneration over the entire filter 201 has been proposed. Specifically, on the downstream side of the particulate filter 201 installed in the middle of the exhaust passage, the nozzle body 225 whose opening gradually expands toward the injection port 224 side, and the rectifying element disposed on the axial center in the nozzle body And a single backwash air nozzle 223 connected to the pressure source 207 via the control valve 210 so that the injection port 224 faces the downstream end surface of the particulate filter 201. Here, as shown in FIG. 11B, the backwash air nozzle 223 includes a hollow conical nozzle body 225 whose inner diameter gradually increases toward the injection port 224, and a support member 26 at the axial center of the nozzle body 225. And a teardrop type rectification planer 227 which is tapered toward the injection port 224 (see, for example, Patent Document 2).

JP-A-01-106915 Japanese Patent Laid-Open No. 04-036008

However, the conventional method has some problems shown below.
(I) In the above example, it is assumed that dust adheres almost evenly to the filter in use, and the purpose is to backwash efficiently by applying air uniformly to the filter. In the dust removal process, the exhaust gas does not flow uniformly to the filter, or because of factors such as uneven shape and distribution of dust, the dust in the exhaust gas does not adhere uniformly to the entire filter. I will make unevenness. Therefore, even when the backflow air is supplied uniformly during blowback, the air passing through the filter is not uniform due to uneven pressure loss of the filter. For this reason, there is a problem that the blowback effect cannot be sufficiently obtained and a part of the dust remains on the filter, and the dust that has peeled off from the filter remains without being discharged from the sampling flow path.

  (Ii) Also, the method of dispersing and uniformly supplying the backwash air is not effective for the formation of a short path, which is a problem during backwashing. That is, when the attached dust is blown off partially or locally, the backwashing air dispersed in the detached part flows into the formed short path. At this time, even if backwashing air uniformly dispersed as described above hits the filter, the short path is not solved, and the problem is that desorption at other locations becomes insufficient and dust remains. there were.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a filter unit having a blow back function that can efficiently remove dust attached to a filter element with a simple and compact structure. Another object of the present invention is to provide a filter unit that can adhere dust in a sample gas to a uniform filter element and obtain a blowback effect more efficiently.

  As a result of intensive studies, the inventor has found that the above object can be achieved by a filter unit having a blowback function shown below, and has completed the present invention.

  That is, the filter unit having a blowback function according to the present invention contains a filter element for cleaning the sample gas, and the primary body and the secondary space are partitioned by the filter element into the primary space. A sample gas introduction part into which a sample gas is introduced into the space part, a clean gas delivery part through which the sample gas that has passed through the filter element is delivered as a clean gas through the secondary space part, and a secondary space part. A blowback gas introduction section into which blowback gas is introduced and an expanding section that gradually spreads from the clean gas supply section, and a direction in which the blowback gas is introduced from the blowback gas introduction section. Has a predetermined inclination angle with respect to the inner surface of the container, and is discharged toward the filter element.

One of the ideal conditions for a filter unit having a blowback function is that the flow of the sample gas on the primary space side (sample gas introduction side) of the filter during use is uniform, and dust adheres uniformly to the filter element. In addition, the flow of the blowback gas from the secondary space side of the filter during backwashing (the supply side of the sample gas (clean gas) cleaned by the filter) is uniform and permeates the filter element uniformly. That is. However, the present invention has found that, during backwashing, it is difficult to prevent a short path in the filter element simply by flowing a blowback gas from a direction perpendicular to the filter. The direction in which the blowback gas is introduced has a predetermined inclination angle with respect to the inner surface of the container,
(I) The blowback gas that hits the inner surface of the container is divided in the left-right direction to generate a swirling flow;
(Ii) By generating a vortex flow in the direction of the filter element, it diffuses widely and forms a turbulent flow-like state. In other words, the flow of the blowback gas is not narrowed in a certain direction, but it has been found that it is preferable to generate a flow almost perpendicular to the filter surface over the entire filter surface. By forming the flow of the blowback gas, dust adhering to the surface of the filter element can be uniformly and efficiently removed. Moreover, such a function can be further enhanced by providing an expanding portion that gradually expands from the clean gas supply portion. That is, although there is no direct flow of blowback gas to the clean gas supply section, some blowback gases reflected by the expanded section having an inclination angle with respect to the filter element reflect the aforementioned gas. In addition to the flow, a flow almost perpendicular to the filter surface is generated over the entire filter surface. Furthermore, the formation of the flow of the blowback gas can provide a technical effect that, when the pressure of the blowback gas is high, the difference in some pressure loss of the filter element to which dust adheres can be ignored. It was. Such a function was confirmed in a verification experiment (cross-sectional flow velocity distribution) described later.

  The present invention is a filter unit having the blowback function, wherein the shape of the container on the side of the secondary space portion is formed in a substantially conical shape gradually spreading from the clean gas supply portion.

  As described above, it is one of the essence of the present invention to generate a flow near the perpendicular to the filter surface with respect to the blowback gas over the entire filter surface. Here, the expanded portion is expanded to form a substantially conical body that gradually spreads from the clean gas supply portion, and by integrating with the inner surface, a larger swirl flow and vortex flow are generated, and higher uniformity is achieved. Can be secured. Moreover, such a configuration of the inner surface can form a simple and compact structure as a filter unit.

  Further, the present invention is a filter unit having the blowback function, wherein the shape of the container on the side of the primary space portion forms a substantially conical shape gradually spreading from the sample gas introduction portion. To do.

  As described above, it is preferable that the flow of the sample gas on the primary space side of the filter during use is uniform, and the dust adheres uniformly to the filter element. In other words, the flow of the sample gas during use and the flow of the blowback gas during backwashing are in an integrated relationship, and if the uniformity is lost in either case, the dust adhered to the filter element or remains during backwashing. Unevenness is generated in the dust, and the influence is further amplified in the dust removal process of the next sample gas and the dust purge process during backwashing. From this point of view, the present invention forms a substantially conical shape that gradually spreads from the sample gas introduction part on the primary space part side of the filter, thereby allowing the sample gas on the primary space part side of the filter to have a simple and compact structure. Flow uniformity can be achieved. In addition, since dust concentrates on a flow with a high flow velocity, the sample gas introduced from the sample gas introduction portion is initially formed with a flow with a high flow velocity at the center, and is gradually dispersed and uniformed by the shape that gradually spreads. The adhesion of dust to the inner surface corresponding to the peripheral portion of the flow can be greatly reduced. Therefore, it is possible to achieve efficient and uniform dust adhesion to the filter element.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. A filter unit (hereinafter referred to as “this unit”) having a blowback function according to the present invention includes a filter element (hereinafter referred to as “filter”) for cleaning a sample gas, and a primary space portion accommodated by the filter element. It is comprised from the container body divided by a secondary space part.

<Basic configuration of this unit>
A basic configuration example (first configuration example) of this unit is shown in FIG. Here, FIG. 1A illustrates the appearance of the unit 10 and includes a sample gas introduction unit 1, a clean gas supply unit 2, and a blowback gas introduction unit 3. FIG. 1B illustrates a bird's-eye view of the gas flow path inside the unit 10, and the primary space 4 and the secondary space 6 are partitioned by the filter 5. In use, the sample gas is introduced into the primary space 4 from the sample gas introduction unit 1, passed through the filter 5, and then cleaned, and then supplied as a clean gas through the secondary space 6. Provided from part 2. Further, during backwashing, blowback gas is introduced from the blowback gas introduction part 3 into the secondary space 6, the filter 5 is backwashed, and then the sample together with dust through the primary space 4. It is discharged from the gas inlet 1.

  FIG. 2 illustrates the structure of the unit 10 in which the filter 5 can be replaced. The unit 10 includes an introduction unit 10a and a delivery unit 10b. Both units are joined via flanges 7a and 7b. The sample gas introduction part 1 is joined to the coupling part 1a and connected to the primary space part 4, and the clean gas supply part 2 is joined to the coupling part 2a and connected to the secondary space part 6 via the flow path 2b. Then, the blowback gas introduction part 3 is joined to the coupling part 3a and connected to the secondary space part 6 through the flow path 3b, and sealing between each gas flow path and the outside is performed by an O-ring 8. The structure is illustrated. By separating the introduction unit 10a and the delivery unit 10b, the filter 5 can be replaced and the inside can be cleaned.

[About the secondary space]
The unit 10 is provided with an expanding portion 9 that gradually expands from the clean gas supply portion 2 in the secondary space portion, and the direction in which the blowback gas is introduced from the blowback gas introduction portion 3 is predetermined with respect to the inner surface. It is characterized in that it is discharged toward the filter 5. Dust adhering to the surface of the filter 5 is uniformly and efficiently removed by generating a flow of blowback gas for the filter 5 during backwashing on the entire filter surface that is nearly perpendicular to the filter surface. can do. At this time, the inclination angle is not particularly limited, and is arbitrarily set depending on the size of the filter 5, the size of the secondary space, the flow rate of the blowback gas, or the like, but is usually preferably about 30 to 60 °. Such a function can be further enhanced by providing the expanding portion 9. The expanding portion 9 can be formed in any shape such as a substantially conical shape, an elliptical cone shape, a pyramid shape, and a shade shape as long as the flow reflected by the blowback gas has a function toward the filter 5. Further, the expansion angle (opening angle with respect to the vertical surface of the filter 5 surface) is not particularly limited, and is arbitrarily set depending on the size of the filter 5, the size of the secondary space, the flow rate of the blowback gas, or the like. However, about 20-60 degrees is preferable normally.

  In particular, it is preferable to expand the expanding portion 9 to form a substantially conical body that gradually spreads from the clean gas supply portion 2. By forming a substantially cone-shaped body in which the inner surface and the expanding portion 9 are integrated, it is possible to generate a larger swirl flow and vortex flow and to ensure higher uniformity. It is also preferable to secure a large internal volume of the secondary space 6 by using a substantially conical body as a part of the inner surface. Specific examples of the shape include shapes as shown in FIGS.

  FIG. 3A illustrates a case where the entire secondary space 6 forms a substantially conical body. The blowback gas introduced from the blowback gas introduction portion 3 provided in a substantially horizontal direction in the drawing hits the inner surface 9a that forms a substantially conical body while diffusing. At this time, as shown in the enlarged view (A1) which is the vertical cross section, the flow Fo as the center hits the inner surface 9a so as to have a predetermined inclination angle α, and diffuses and has a predetermined width directionality. Similarly, the flows Fa, Fb, etc., have a wider angle or a narrower angle than the inclination angle α and hit the inner surface 9a. These flows reflected by the inner surface 9a are further diffused and flow toward the filter 5 to generate a flow almost perpendicular to the filter surface over the entire filter surface and are discharged. Note that the blowback gas introduction portion 3 is attached to the blowback gas in the direction of introduction of the blowback gas so as to have a predetermined inclination angle α with respect to the inner surface 9 a and perpendicular to the filter surface toward the filter 5. As long as a near flow is generated over the entire filter surface and discharged, the flow may be in an arbitrary direction instead of the substantially horizontal direction in the figure.

  On the other hand, as shown in the ff ′ cross-sectional view (A2) which is the horizontal cross section, the flow Fo hits the inner surface 9a and is divided into left and right directions by the curved surface to generate a swirling flow, and diffuses to have a predetermined width. The directional flows Fc, Fd, etc. also form part of the swirling flow. While these flows are further diffused to generate a vortex flow, a flow perpendicular to the filter surface is generated on the entire filter surface toward the filter 5 and discharged. As described above, the blowback gas is discharged from any direction by generating a flow almost perpendicular to the filter surface toward the filter 5 over the entire filter surface, thereby discharging the dust attached to the surface of the filter 5. Can be eliminated evenly and efficiently. The blowback gas introduction portion 3 or the blowback gas is introduced in a direction in which a swirl flow is generated and a vortex flow is generated while being further diffused toward the filter 5 toward the filter surface. As long as a substantially vertical flow is generated and discharged over the entire filter surface, as shown in the ff ′ cross-sectional view (A3), it is not in the direction of the substantially central axis in the drawing but in any direction. It doesn't matter. Further, here, the flow of the blowback gas is divided into the vertical and horizontal directions for the sake of explanation, but it goes without saying that the flow direction is not limited to this.

  FIG. 3B illustrates a case where a part of the secondary space 6 forms a substantially conical body. As in FIG. 3A, the blowback gas introduced from the blowback gas introduction portion 3 provided in a substantially horizontal direction in the drawing hits the inner surface 9a that forms a substantially conical body while diffusing, The dust adhering to the surface of the filter 5 is uniformly and efficiently removed by generating a flow almost perpendicular to the filter surface toward the filter 5 from all directions and discharging the entire filter surface. Can do. In this configuration, the blowback gas having a flow toward the filter 5 is further diffused by the space 6a having the inner surface 9b, and a flow that is more perpendicular to the filter surface can be generated over the entire filter surface. The inner surface 9b is not necessarily limited to being perpendicular to the filter 5, but has an inclination angle different from the inclination angle of the inner surface 9a and has a narrower inclination angle than the inner surface 9a. Thus, it is possible to prevent dust from remaining at the end of the filter 5.

  FIG. 3C shows a configuration in which a part of the secondary space 6 forms a substantially conical body as in FIG. 3B, but the blowback gas introduction part 3 is provided on the inner surface 9c. The case where it is provided in a direction that is not horizontal in the drawing and the blowback gas hits the inner surface 9c with a predetermined inclination angle β while diffusing is illustrated. The mode in which the blowback gas including the flow Fo that is the center of the blowback gas has a predetermined inclination angle β with respect to the inner surface 9c is the same as the mode shown in the enlarged view (A1), and the gg ′ cross section. The mode in which the blowback gas hits the inner surface 9c is substantially the same as the mode shown in the section ff ′ (A2) or (A3) except that the cross-sectional shape of the secondary space 6 is elliptical. It is. Therefore, the dust adhering to the surface of the filter 5 is uniformly and efficiently removed by generating a flow almost perpendicular to the filter surface toward the filter 5 from all directions and discharging the entire filter surface. can do. The inner surface 9c is not necessarily limited to being perpendicular to the filter 5, but has an inclination angle different from the inclination angle of the inner surface 9a, and has a narrower inclination angle than the inner surface 9a. Thus, it is possible to prevent dust from remaining at the end of the filter 5.

As described above, “the direction in which the blowback gas is introduced from the blowback gas introduction portion (hereinafter referred to as“ BG introduction direction ”) has a predetermined inclination angle with respect to the inner surface of the container, and the filter element When the flow that is nearly perpendicular to the filter surface is generated over the entire filter surface,
(1) When the BG introduction direction with respect to the inner surface of the container having an inclination with respect to the filter surface is parallel to the filter surface or has an inclination equal to or less than the inclination angle (2) The direction in which the BG introduction direction is repeated by the inner surface of the container Is perpendicular to the filter surface. For example, the BG introduction direction does not have such a function in a tangential direction of the inner surface of the container or a direction approximate thereto.

[About the primary space]
As shown in FIG. 2, the primary space portion 4 preferably forms a substantially conical shape that gradually spreads from the sample gas introduction portion 1 (the coupling portion 1 a thereof). By introducing the sample gas from the conical tip, diffusion of the sample gas into the entire primary space 4 can make the flow of the sample gas on the primary space side of the filter 5 uniform. Further, it is possible to extremely reduce the adhesion of dust to the inner surface 4a, and it is possible to realize efficient and uniform adhesion of dust to the filter 5. Even in such a configuration, the flow rate to the central part of the filter 5 remains somewhat larger than the surrounding area, but the increase in the amount of dust adhering to the central part of the filter 5 is caused by the pressure loss of the filter 5 in the central part. This increases the amount of dust and facilitates the adhesion of dust to the peripheral portion, and the portion where much dust adheres gradually diffuses to the periphery. As a result, uniform adhesion of dust can be formed on the entire filter surface. Such a function can be realized by forming a shape in which the primary space portion 4 allows diffusion of the sample gas, that is, a substantially conical shape that gradually expands. At this time, the opening angle of the substantially conical body (opening with respect to the vertical surface of the filter 5 surface) is not particularly limited, and is arbitrarily set depending on the size of the filter 5, the size of the primary space, the flow rate of the sample gas, or the like. However, about 20 to 60 ° is usually preferable.

  Further, at this time, as illustrated in FIG. 4, a convex step portion 1 b is provided on the center side of the primary space portion 4 in the connection portion 1 a between the sample gas introduction portion 1 and the inner surface 4 a forming a substantially conical shape body. It is preferable to have. The effect of narrowing the sample gas by the convex step 1b is generated, and as will be described later, when a sample gas having a predetermined flow rate or more is introduced, a state in which the inner surface 4a is hardly in contact with the flow containing dust is formed. Can do. In other words, dust may easily adhere to a part of the inner surface 4a due to the possibility of eddy currents in the vicinity of the connecting portion 1a without the convex step portion 1b, and the sample gas is narrowed down by the convex step portion 1b. By utilizing the characteristics of dust concentrated in a flow with a high flow velocity, it is possible to contribute to uniform dispersion of dust simultaneously with the uniform flow of sample gas, and to reduce / prevent dust adhesion to the inner surface 4a. In addition, this increases the function of diffusing a portion where a large amount of dust adheres to the filter 5 to the periphery, thereby enabling more uniform dust adhesion.

<Second configuration example of this unit>
FIG. 5A shows a bird's-eye view of the gas flow path inside the second configuration example of this unit. A second blowback gas introduction part 32 (hereinafter referred to as “B2 introduction part”) is provided in the primary space part 4, and a blowback gas introduction part 31 (hereinafter referred to as “B1 introduction part” provided in the secondary space part 6 is provided. The blowback gas is introduced from the B2 introduction part 32 in association with the introduction of the blowback gas from the above. Dust adhering to the inner surface 4a during use is difficult to remove by blowback gas during backwashing, and part of the dust detached from the filter 5 during backwashing tends to adhere to the inner surface 4a. By introducing the blowback gas directly into the primary space 4, dust attached to the inner surface 4 a during use can be removed, and adhesion of the detached dust to the inner surface 4 a during backwashing can be prevented in advance. it can. At this time, as shown in FIG. 5 (B), the B2 introduction part 32 forms a swirl flow along the inner surface 4a by being arranged in the tangential direction of the inner surface 4a, that is, along the outer edge of the filter. It is possible to effectively remove dust adhering to 4a and prevent the desorbed dust from adhering to the inner surface 4a during backwashing. In the second configuration example, one blowback gas is directly introduced into the primary space portion 4. However, a plurality of blowback gas introduction portions are further provided for blowback from several directions. It is also possible to adopt a configuration in which a gas is introduced to form such a highly functional flow.

<Third configuration example of this unit>
FIG. 6A illustrates a bird's-eye view of the gas flow path inside the third configuration example of this unit. A third blowback gas introduction portion 33 (hereinafter referred to as “B3 introduction portion”) is provided in the secondary space portion 6 so as to face the B1 introduction portion 31, and the blowback gas from the B1 introduction portion 31 is supplied. In connection with the introduction, a blowback gas is introduced from the B3 introduction part. By introducing not only blowback gas from one direction but also blowback gas from a plurality of directions, diffusion of blowback gas from the B1 introduction portion 31 is promoted, and this flow is merged with the filter 5. On the other hand, it is possible to generate a flow almost perpendicular to the filter surface over the entire filter surface.

  At this time, as shown in FIG. 6B, the flow of the blowback gas from the B3 gas introduction portion 33 is tangential to the inner surface 9 (corresponding to any of the inner surfaces 9a to 9c in FIG. 3), that is, the filter. It is preferable to arrange the B3 gas introduction part 33 so as to be in a direction along the outer edge part. This forms a swirl flow along the inner surface 9, promotes diffusion of blowback gas from the B1 introduction portion 31, merges with this flow, and is more perpendicular to the filter surface than the filter 5. Flow can be generated across the filter surface. Further, by forming the flow of the blowback gas from the B3 gas introduction portion 33 so as to be substantially parallel to the flow from the B1 gas introduction portion 31 and deviating by a predetermined distance, the above flow is formed and the flow is further enhanced. A simple swirl flow can be formed. Furthermore, a plurality of blowback gas introduction portions are provided, which are introduced from various directions to form a flow of blowback gas that generates a flow that is more perpendicular to the filter surface over the entire filter surface. Is also possible. Alternatively, it is possible to adopt a configuration in which a flow of blowback gas concentrated only at the center portion or the peripheral portion of the filter 5 is formed. Moreover, the flow of the blowback gas to the secondary space 6 in the second configuration example can be applied to the third configuration example.

<Verification of flow of blowback gas and sample gas in this unit>
[Verification 1]
As a first configuration example of this unit, the flow of the blowback gas when the primary space portion 4 and the secondary space portion 6 as a whole formed a substantially conical body was verified, and its technical effect was confirmed.
(1) Verification Method As shown in FIGS. 7A and 7B, the direction in which the blowback gas is introduced from the blowback gas inlet 3 (IN) is substantially parallel to the surface of the filter 5 and the center thereof. The direction was substantially along the line. The inner surface 9 a has an inclination angle α, is reflected, flows toward the filter 5, and is discharged from the sample gas introduction unit 1 (OUT) through the primary space 4.

(2) Verification Results FIGS. 7A to 7C show the simulation results of this unit. The gas flow rate is expressed in shades, and the darker the color, the higher the flow rate. The vertical cross section shown in FIG. 7A shows a flow in which the blowback gas is dispersed and uniformly distributed to the filter 5 and converges on the sample gas introduction unit 1 in the primary space 4. It shows that. In the flow velocity distribution diagram of the gas in the vicinity of the surface on the secondary space 6 side of the filter 5 shown in FIG. 7B, the flow velocity of the blowback gas is large in a wide region from the vicinity of the inner surface 9a to the vicinity of the central portion. This shows an improvement from the distributed distribution around the inner surface or in a limited area in the local area. As a result, in the gas flow velocity distribution on the primary space portion 4 side immediately after passing through the filter 5 shown in FIG. 7C, although the influence of the distribution on the secondary space portion 6 side is seen, a highly uniform gas The flow velocity distribution was observed, and a high blowback effect could be expected. In particular, the blowback gas introduced substantially horizontally in the figure has a uniform flow velocity distribution that is nearly ideal and changes its direction substantially perpendicular to the filter 5 due to the pressure loss of the filter 5.

[Verification 2]
As a third configuration example of this unit, the flow of blowback gas when a plurality of blowback gases were introduced was verified, and the technical effect was confirmed.
(1) Verification Method As shown in FIGS. 8A and 8B, as in the above [Verification 1], at the same time as the blowback gas from the B1 introduction portion 31 (IN31), it is substantially parallel and deviated from this. The blowback gas from the B3 introduction part 33 (IN33) was introduced so as to be tangential to the inner surface 9a. Both flow together and flow toward the filter 5, and are discharged from the sample gas introduction unit 1 (OUT) via the primary space 4.

(2) Verification Results FIGS. 8A to 8C show simulation results of this unit. The vertical cross section shown in FIG. 8 (A) has a larger distribution function of the blowback gas in the secondary space 6 and circulates more uniformly with respect to the filter 5, and the uniformity of the flow velocity in the primary space 4. It shows that a high flow of is formed. Further, in the flow velocity distribution diagram of the gas in the vicinity of the surface on the secondary space 6 side of the filter 5 shown in FIG. 8B, the flow velocity of the blowback gas is uniform over a wide area of the entire filter 5 surface. It is shown that. As a result, on the primary space 4 side immediately after passing through the filter 5 shown in FIG. 8C, a very uniform gas flow velocity distribution is seen, and a high blowback effect can be expected. It was. Further, as in [Verification 1], the direction of the filter 5 is substantially changed in the vertical direction due to the pressure loss of the filter 5, and the flow velocity distribution is more uniform.

[Verification 3]
In this unit having a conical primary space portion, the flow of the sample gas when the convex step portion 1b is provided in the vicinity of the sample gas introduction portion 1 of the primary space portion 4 as shown in FIG. 4 is verified. The technical effect was confirmed.
(1) Verification Method As shown in FIG. 9, the sample gas introduced from the sample gas introduction part 1 (IN) is narrowed down by the convex step part 1b, and the primary space part 4, the filters 5, 2 It is delivered via the secondary space 6 and the clean gas delivery part 2 (OUT). The flow of the sample gas at this time was simulated as the flow velocity distribution.

(2) Verification results FIG. 9 shows the simulation results of this unit. In the primary space 4, it is possible to form a flow with almost no contact with the inner surface 4 a. The adhesion of dust to the inner surface 4a can be avoided. Further, as shown in the sectional view along the line aa ′ due to the pressure loss in the filter 5, the sample gas is dispersed over the entire surface of the filter 5, forms a substantially uniform flow velocity distribution, and passes through the filter 5. However, since the flow velocity is reduced in the peripheral portion of the filter 5 as the gas flow is narrowed down, there is less dust adhesion, and less dust adheres to the inner surface 4a during backwashing, which is high. The result is that a blow back effect can be expected. The clean gas cleaned by the filter 5 converges according to the shape of the secondary space portion 6 and forms a flow to the clean gas supply portion 2 in a state where the flow velocity at the center is slightly high.

Explanatory drawing which shows the basic structural example of the filter unit which has the blowback function which concerns on this invention. Explanatory drawing which illustrates the structure of the basic structural example of the filter unit which concerns on this invention. Explanatory drawing which illustrates the specific form of the secondary space part of the filter unit which concerns on this invention. Explanatory drawing which illustrates the form of the primary space part in the case where it has a convex step part in a sample gas introduction part. Explanatory drawing which illustrates the bird's-eye view of the internal gas flow path of the 2nd structural example of the filter unit which concerns on this invention. Explanatory drawing which illustrates the bird's-eye view of the internal gas flow path of the 3rd structural example of the filter unit which concerns on this invention. Explanatory drawing which illustrates the flow of the gas for blowbacks in the 1st structural example of the filter unit which concerns on this invention. Explanatory drawing which illustrates the flow of the gas for blowbacks in the 3rd structural example of the filter unit which concerns on this invention. Explanatory drawing which illustrates the flow of sample gas in case a sample gas introduction part has a convex step part. Explanatory drawing which shows the particulate collection and purification apparatus which concerns on a prior art. Explanatory drawing which shows the backwash reproduction | regeneration apparatus of the particulate filter which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sample gas introduction part 1a, 2a, 3a Joint part 2 Clean gas supply part 3 Blowback gas introduction part 3b Flow path 4 Primary space part 4a, 9a Inner surface 5 Filter element (filter)
6 Secondary space portion 7a, 7b Flange 8 O-ring 9 Expanded portion 10 Filter unit according to the present invention (this unit)
10a Introduction unit 10b Delivery unit

Claims (3)

A sample gas introduction unit that contains a filter element for cleaning the sample gas, and into which the sample gas is introduced into the primary space part into a container that is partitioned by the filter element into a primary space part and a secondary space part; A clean gas supply section through which the sample gas that has passed through the filter element is supplied as clean gas through the secondary space section; and a blowback gas introduction section in which blowback gas is introduced into the secondary space section; And an expanding portion that gradually spreads from the clean gas supply portion, and
The blowback characterized in that the blowback gas introduction direction from the blowback gas introduction portion has a predetermined inclination angle with respect to the inner surface of the container, and is discharged toward the filter element. Filter unit with function.   The filter unit having a blowback function according to claim 1, wherein the shape of the container on the side of the secondary space portion forms a substantially conical shape that gradually spreads from the clean gas supply portion.   The filter unit having a blowback function according to claim 1 or 2, wherein the shape of the container on the side of the primary space portion forms a substantially conical shape that gradually spreads from the sample gas introduction portion.

Images