JP2008049302A - Venturi tube and bag filter retainer including the same - Google Patents

Abstract

A part of compressed air ejected from a nozzle disposed above can be ejected from an opening formed in a peripheral wall portion of a venturi tube, and a negative pressure generated near the outer periphery of the venturi tube can be reduced. In addition, the entire filter cloth including the upper end of the retainer can be swollen outward to ensure that the dust adhering to the filter cloth can be removed, and the effective filtration area can be expanded, improving the dust collection efficiency. An object of the present invention is to provide a venturi tube that can alleviate sticking of the filter cloth on the upper end side of the retainer and prevent breakage of the filter cloth and is excellent in the long life of the filter cloth.
A venturi tube that is inserted and disposed in a central portion of an upper end side of a bag filter retainer, and includes a plurality of openings formed on a circumference of a peripheral wall portion, and a lower end portion of the opening portion. And a guide portion disposed on the inner peripheral side of the peripheral wall portion.
[Selection] Figure 1

Description

  The present invention relates to a venturi tube disposed on a bag filter retainer that supports a filter cloth of a dust collector from the inside, and a bag filter retainer including the venturi tube.

Conventionally, as a dust collector, a filter cloth (filter bag) that separates and collects dust by passing a dust-containing airflow, and a support frame (hereinafter referred to as a retainer) that supports the filter cloth from the inside to maintain the shape of the filter cloth. The thing provided with these is used. When the dust collector is operated, the filter cloth collects dust, and the loss of suction force increases with the lapse of operation time. Therefore, it is necessary to remove the collected dust intermittently or continuously. For example, as described in (Patent Document 1) and (Patent Document 2), a venturi pipe is provided on the upper end side of the retainer, and a pulse jet (compressed air) is provided. There is a pulse jet type dust collector that backwashes the filter cloth by spraying the nozzle toward the venturi tube.
FIG. 5A is a schematic cross-sectional view of the main part showing the state of the filter cloth at the time of dust collection of a conventional bag filter retainer in a dust collector equipped with a pulse jet type wipe-off mechanism, and FIG. It is a principal part schematic sectional drawing which shows the state of the filter cloth at the time of dust removal of the conventional bag filter retainer in the dust collector provided with the jet-type removal mechanism (at the time of backwashing).
In FIG. 5, reference numeral 50 denotes a conventional bag filter retainer disposed on an upper portion of a dust collector equipped with a pulse jet type wiping mechanism 70, 51 denotes a retainer body of the bag filter retainer 50, and 52 denotes an upper end of the retainer body 51. The venturi tube 52a is fixedly disposed on the portion, 52a is a flange portion at the upper end of the venturi tube 52, 55 is a cylindrical filter cloth disposed on the outer periphery of the retainer body 51, and 60 is a dust collector for holding the bag filter retainer 50. A partition plate (cell plate) 70 a is a nozzle of a pulse jet type wiping mechanism 70 that is disposed above the venturi tube 52 and injects compressed air toward the venturi tube 52.

As shown in FIG. 5 (a), the dust-containing airflow that has flowed into the dust-collecting chamber from the dust-containing airflow inlet of the dust collector is removed from the outside of the filter cloth 55 and flows into the filter cloth 55, and the dust is filtered. The clean airflow collected on the outer periphery of 55 and separated and collected is discharged from the venturi tube 52. A nozzle 70a of a wiping mechanism 70 is disposed above the venturi tube 52. As shown in FIG. 5B, compressed air is supplied from the nozzle 70a to the inside of the filter cloth 55 from the venturi tube 52 at regular intervals. The dust sprayed and adhered to the filter cloth 55 is instantaneously removed to the outside of the filter cloth 55.
JP 10-2111410 A Japanese Patent Laid-Open No. 8-299732

However, when the operation of the filter cloth 55 at the time of dust removal is observed for the pulse jet type dust collector, when the pulse jet (compressed air) is injected from the nozzle 70a, the venturi tube 52 on the upper end side of the retainer main body 51 is observed. As shown in FIG. 5B, a negative pressure is generated in the vicinity of the outer periphery of the filter cloth 55. As shown in FIG. 5B, the filter cloth 55 is attracted to the retainer main body 51 and is in a suction state. I found out that the dust was not removed. Therefore, when a sensor (digital micro differential pressure gauge) was attached in the longitudinal direction of the retainer main body 51 and the pressure was measured, it was almost 500 mm to 600 mm from the upper end of the filter cloth 55 regardless of the total length (3 m to 9 m) of the retainer main body 51. It was found that negative pressure was generated near the outer periphery of the venturi tube 52 within a certain range. FIGS. 6A to 6C are diagrams showing measurement results of pressures at positions 200 mm, 350 mm, and 3000 mm from the upper end when a pulse jet (compressed air) having a pressure of 294 kPa is injected for 0.2 seconds. is there. This phenomenon was confirmed in the same manner even when the venturi tube 52 was not provided.
From the above, the following problems in the prior art have been clarified.
(1) Even if a positive pressure pulse jet (compressed air) is injected, the injection speed is fast (about 90 m / s), so that positive pressure is generated only for a moment (about 0.02 seconds) ( 6 (a) and 6 (b)), the filter cloth 55 cannot react, remains in the suction state, dust cannot be removed at the upper end of the filter cloth 55, and the dust collection efficiency decreases. To do.
(2) When the high-speed pulse jet (compressed air) passes through the venturi pipe, the pressure inside the retainer main body 51 is reduced by the venturi effect. At this time, the dust-containing airflow outside the bag filter retainer 50 passes through the filter cloth 55 and is taken into the retainer main body 51 as a clean airflow, but the supply of the clean airflow is not in time due to the resistance of the filter cloth 55, Entrainment negative pressure is generated. As a result, the filter cloth 55 is attracted to the outer periphery of the retainer body 51 by both the blower negative pressure and the entanglement negative pressure, and the filter cloth 55 is easily rubbed and damaged by the retainer body 51, resulting in a long life. Lack of sex.
(3) In particular, at the position of the boundary where the negative pressure of 500 mm to 600 mm changes from the upper end of the filter cloth 55 to the positive pressure, the filter cloth 55 is extremely attracted inward and outward, and damage due to bending becomes significant.
(4) When the pressure of the pulse jet is increased, when the venturi tube 52 is removed, or when the venturi tube 52 is attached to the outside of the retainer body 51, the negative pressure at the upper end of the filter cloth 55 is further increased. The filter cloth 55 is easily damaged. Therefore, the pressure of the pulse jet is usually in the range of about 196 kPa to 686 kPa, but in order to prevent the filter cloth 55 from being damaged, there are places where the pressure of the pulse jet is suppressed to 392 kPa or less. In the retainer, the pulse jet does not reach the lower end of the retainer body 51, and there is a tendency that dust cannot be removed at the upper and lower ends.

  The present invention solves the above-described conventional problems, and a part of the compressed air injected from the nozzle disposed above is ejected from an opening formed in the peripheral wall portion of the venturi tube, and near the outer periphery of the venturi tube. The generated negative pressure can be relieved, the entire filter cloth including the upper end side of the retainer is inflated outwardly, the dust adhering to the filter cloth can be surely removed, the effective filtration area is expanded, It is possible to improve the dust collection efficiency and to ease the filter cloth sticking on the upper end side of the retainer to prevent the filter cloth from being damaged. An object of the present invention is to provide a bug filter retainer.

In order to solve the above-described conventional problems, the venturi tube of the present invention and the bag filter retainer including the same have the following configurations.
The venturi tube according to claim 1 of the present invention is a venturi tube that is disposed by being inserted into the central portion on the upper end side of the bag filter retainer, and includes a plurality of tubes formed on the circumference of the peripheral wall portion. It has the structure provided with the opening part and the guide part arrange | positioned in the inner peripheral side of the said surrounding wall part at the lower end part of the said opening part.
With this configuration, the following operation is obtained.
(1) Since it has a plurality of openings formed on the circumference of the peripheral wall portion and a guide portion disposed on the inner peripheral side of the peripheral wall portion at the lower end portion of the opening portion, when the filter cloth is backwashed When compressed air is sprayed from the nozzles arranged on the upper part of the bag filter retainer, a part of the compressed air is guided by the guide part and ejected from the opening to the outer peripheral direction of the peripheral wall (the radial direction of the retainer). The negative pressure generated on the upper end side of the retainer can be reduced, the entire filter cloth including the upper end side of the retainer can be inflated almost uniformly outward, and the dust adhering to the filter cloth can be expanded. The dust can be reliably removed, the maintenance is highly reliable, the effective filtration area during dust collection can be expanded to improve the dust collection efficiency, and the energy saving performance is excellent.
(2) When the filter cloth is backwashed, a part of the compressed air injected from the nozzle disposed on the upper part of the bag filter retainer is ejected from the opening toward the radial direction (outer peripheral direction) of the retainer. By reducing the negative pressure generated at the upper end, the filter cloth is strongly attracted at the upper end of the retainer and can be prevented from sticking to the retainer body. Can be improved.
(3) By arranging a plurality of openings on the circumference of the peripheral wall portion, compressed air injected from the nozzles during backwashing can be uniformly ejected from the entire circumference of the peripheral wall portion toward the outer peripheral side of the retainer. In addition, the filter cloth on the upper end side of the retainer can be reliably inflated outward over the entire circumference, and dust can be efficiently removed to keep the dust removal efficiency substantially constant.
(4) By arranging a plurality of openings on the circumference of the peripheral wall portion, it is possible to prevent a negative pressure from being partially generated on the outer periphery of the peripheral wall portion, and it is excellent in uniformity of the negative pressure reduction effect and surely Dust can be removed, and the filtration performance is reliable and the filter cloth has a long service life.

Here, the shape, number, area, arrangement, and the like of the opening of the peripheral wall can be appropriately selected according to the diameter of the retainer body of the bag filter retainer, the diameter and length of the venturi tube, and the like. For example, as the shape of the opening, for example, a semicircular shape, a semi-elliptical shape, or a long hole shape is preferably used.
The openings of the peripheral wall portion are preferably arranged at 2 to 8 locations, preferably 3 to 6 locations on the circumference of the peripheral wall portion of the venturi tube. As the number of openings decreases from three, the compressed air ejected from the peripheral wall becomes more easily biased, and the filter cloth near the outer periphery of the peripheral wall becomes less likely to swell uniformly, so that dust can be removed from the upper end of the retainer. The drop effect tends to be inadequate, and the amount of compressed air that passes through the inside of the venturi pipe and reaches the lower end of the retainer tends to be insufficient as the number of drops increases. There is a tendency that the payout effect is insufficient. In particular, when the number of openings is less than two, the compressed air ejected from the peripheral wall is biased, and the filter cloth in the vicinity of the outer periphery of the peripheral wall is unevenly swelled, and dust at the upper end of the retainer is removed. It becomes difficult to reach the lower end of the retainer with the compressed air that has passed through the inside of the venturi pipe as it becomes more than 8 places, and it becomes difficult to remove dust on the lower end side of the retainer. Is also not preferred.
Also, by ensuring a sufficient opening area by forming the opening in the shape of a long hole, it becomes easy for clean air sucked by the blower during dust collection to enter the inside of the venturi through the opening, The load on the blower can be reduced.

The arrangement of the openings in the peripheral wall portion may be equal or unequal, but in particular, when the openings are arranged at equal angular intervals on the circumference of the peripheral wall portion of the venturi tube, it radiates from the entire circumference of the peripheral wall portion. Since compressed air is ejected, the air flow is uniform over the entire circumference of the peripheral wall, the filter cloth can be evenly inflated, and dust can be removed without unevenness. Excellent stability.
Further, the opening can be provided in a plurality of steps in the longitudinal direction of the peripheral wall portion, and the number of steps in which the opening is arranged can be arbitrarily selected according to the length of each opening and the entire length of the peripheral wall portion. When arranging a plurality of openings, the length of the opening for each stage may be the same or different. Moreover, the length of each opening part in each stage does not need to be the same, For example, the opening part of 2 types of length can also be arranged alternately.
When a plurality of openings are arranged in the longitudinal direction of the peripheral wall, the compressed air injected from the nozzle at the time of backwashing can be ejected from the opening toward the outer peripheral side of the retainer over almost the entire outer periphery of the peripheral wall. The filter cloth on the upper end side of the retainer can be surely inflated outward over the entire length of the negative pressure generating region, and dust can be efficiently removed. In particular, when the openings arranged on the circumference of the peripheral wall portion are arranged in a staggered manner so as to be alternately arranged with the adjacent openings in the longitudinal direction, the openings are densely packed without reducing the strength of the peripheral wall portion. The opening area can be increased, and compressed air can be ejected uniformly and uniformly from the entire surface of the peripheral wall, and the efficiency and reliability of the negative pressure reduction effect are excellent. Efficiency can be improved.

As the guide part, when the opening part is formed in the peripheral wall part, a part integrally formed with the peripheral wall part is preferably used by cutting out except the lower end part and bending the inner part of the peripheral wall part. Moreover, you may attach the guide part formed with the flat member from the lower end part of each opening part by welding or screwing.
Moreover, you may integrally form several guide part corresponding to the position of each opening part of a surrounding wall part. For example, a central opening may be provided at the center of a disk-shaped member having an outer diameter equivalent to the inner diameter of the peripheral wall, and a plurality of guides corresponding to the positions of the openings may be formed around the center opening. The opening area of the central opening can be appropriately selected according to the inner diameter of the venturi tube and the number of openings formed in the peripheral wall. Further, considering the balance between the amount of compressed air ejected from the opening to the outer periphery of the retainer and the amount of compressed air ejected from the central opening to the lower end side of the retainer, the opening area and shape of the central opening are determined. .
In particular, when a plurality of openings are formed in the peripheral wall portion, a peripheral wall guide portion formed integrally with the peripheral wall portion is suitably used for the opening formed in the middle of the peripheral wall portion in the longitudinal direction. This is because there is no need for welding or screwing, and productivity is excellent. In addition, an annular bottom guide portion in which a plurality of guide portions are integrally formed is preferably used for the opening formed in the vicinity of the lower end portion of the peripheral wall portion. This is because it can be easily assembled and is excellent in productivity by being arranged at the lower end of the venturi tube.

  In addition, the attachment angle α formed by the upper end side of the peripheral wall portion and the guide portion is preferably 30 to 90 degrees. As the mounting angle α of the guide part becomes smaller than 30 degrees, the distance between the opening part and the guide part becomes narrow, and it becomes difficult for the compressed air to be ejected from the opening part. It tends to flow to the lower end side of the retainer without spreading in the outer peripheral direction), and it tends to be difficult to swell the filter cloth on the upper end side (outer periphery of the peripheral wall portion) outward, and as it becomes larger than 90 degrees, Compressed air that hits the guide cannot be guided to the opening, and the compressed air easily flows through the venturi tube to the lower end of the retainer, and is filtered on the upper end of the retainer (the outer periphery of the peripheral wall). It tends to be difficult to inflate the fabric outwards, both of which are undesirable.

The invention according to claim 2 is the venturi according to claim 1, wherein the plurality of openings are arranged in a staggered pattern on the peripheral wall.
With this configuration, in addition to the operation obtained in the first aspect, the following operation can be obtained.
(1) Since a plurality of openings are arranged in a staggered manner on the peripheral wall portion, the compressed air injected from the nozzle during backwashing can be opened regardless of the circumferential or longitudinal position of the peripheral wall portion. Can be reliably ejected toward the outer periphery of the retainer, and the filter cloth on the upper end of the retainer can be inflated outwards without any unevenness, which can improve dust removal efficiency and reliability of filtration performance. Excellent.

  Here, a plurality of openings are provided by arranging openings at equiangular intervals on the circumference of each stage and arranging the positions of the openings of adjacent stages on the top and bottom so as to be slightly shifted in the circumferential direction. The parts can be arranged in a staggered manner. For example, when the openings are arranged in two stages, by arranging the positions of the upper and lower openings at a half pitch in the circumferential direction, the openings can be arranged uniformly over the entire surface of the peripheral wall, and negative pressure Excellent uniformity of improvement effect.

A third aspect of the present invention is the venturi tube according to the first or second aspect, wherein the flange portion is disposed on the outer periphery of the upper end of the peripheral wall portion, and is formed on the flange portion and is formed from the upper end side to the lower end side And a flange portion opening portion having a tapered inner peripheral surface formed to expand toward the surface.
With this configuration, in addition to the operation obtained in the first or second aspect, the following operation can be obtained.
(1) Protruding the guide portion on the inner peripheral side of the peripheral wall portion increases the resistance inside the venturi tube and reduces the cross-sectional area of the flow path, but by forming the flange portion opening in the flange portion In addition, the cross-sectional area of the upper end of the retainer can be ensured, the load on the blower used for suction during dust collection can be prevented from increasing, and the reliability is excellent.
(2) The flange opening has a tapered inner peripheral surface formed by expanding from the upper end side toward the lower end side, thereby reducing pressure loss caused by suction of the blower during dust collection. As a result, the load on the blower can be reduced, the generation of negative pressure after pulse jet injection during backwashing can be suppressed, the negative pressure improvement effect can be improved, dust removal efficiency, and filtration performance reliability can be improved. Can be improved.

Here, the shape, number, arrangement and the like of the flange opening can be appropriately selected according to the diameter of the retainer body of the bag filter retainer, the diameter of the venturi tube, and the like. For example, an elliptical shape such as a circular shape or an elliptical shape is preferably used as the shape of the opening of the flange portion. In addition, it is preferable to arrange | position a flange part opening part at equal angular intervals on the circumference of a flange part. This is because the flow of clean air sucked by the blower becomes uniform over the entire outer periphery of the peripheral wall portion, and the filtration can be efficiently performed on the entire surface of the filter cloth, and the filtration performance is stable.
Moreover, although the opening area (total area) of a flange part opening part is based also on the shape, area, etc. of a guide part, 3 to 8% of the cross-sectional area of a retainer main body is preferable. As the opening area (total area) of the flange opening becomes smaller than 3% of the cross-sectional area of the retainer body, the load of the blower used for suction during dust collection tends to increase, and as it becomes larger than 8%. When a pulse jet is ejected when dust is removed, an attracting occurs between the positive pressure in the filter cloth by the pulse jet and the suction negative pressure of the blower on the upper part of the partition plate (cell plate), and the upper end of the retainer body The negative pressure reduction effect at the part becomes insufficient, and the positive pressure of the pulse jet also does not reach the lower end of the retainer body, and there is a tendency that dust removal at the lower end part of the retainer body tends to be insufficient. It is not preferable.

According to a fourth aspect of the present invention, there is provided a bag filter retainer comprising: a plurality of fixing rings formed annularly with a metal wire and arranged at predetermined intervals; and a plurality of vertical wires joined to the outside of the fixing ring. And a venturi tube according to any one of claims 1 to 3, wherein the venturi tube is inserted and disposed in a central portion on an upper end side of the retainer main body. ing.
With this configuration, the following operation is obtained.
(1) A venturi tube is inserted and disposed at the center of the upper end side of the retainer main body, so that a part of the compressed air injected from the nozzle above the retainer during backwashing of the filter cloth can be part of the peripheral wall of the venturi tube. It is possible to reduce the negative pressure generated on the upper end side of the retainer main body, and to inflate the entire filter cloth including the upper end side of the retainer main body outward from the opening provided in the portion in the radial direction of the retainer main body. Dust adhering to the filter cloth can be surely removed, the effective filtration area during dust collection can be expanded, dust collection efficiency can be improved, and the filter cloth is strongly attracted at the upper end of the retainer body The filter cloth can be prevented from being damaged and the filter cloth can be prevented from being damaged, and the filter cloth has a long life.
(2) A venturi tube having a flange opening at the flange portion is inserted and disposed at the center of the upper end side of the retainer main body, so that the cross-sectional area of the upper end portion of the retainer is reduced to a conventional venturi tube. It can be enlarged compared to the one provided, the load on the blower used for suction during dust collection can be reduced, and energy saving is excellent.
(3) Since the suction negative pressure by the blower during dust collection increases at the upper end of the retainer body, the amount of dust adhering to the upper end also increases, but it is reversed by attaching a venturi tube with an opening in the peripheral wall. By reducing the generation of negative pressure due to pulse jet (compressed air) during washing, the effect of dust removal on the upper end side of the retainer body can be improved, and energy saving and filtration performance reliability are excellent.

As described above, according to the venturi tube of the present invention and the bag filter retainer including the same, the following advantageous effects can be obtained.
According to the invention of claim 1,
(1) A part of a pulse jet (compressed air) injected at the time of backwashing of the filter cloth is ejected in the radial direction (outer peripheral direction) of the retainer from the opening formed in the peripheral wall, and the filter including the upper end side of the retainer By inflating the entire cloth almost uniformly outward, dust attached to the filter cloth can be surely removed to increase the effective filtration area, improving the maintainability and dust collection efficiency of the bag filter retainer. In addition, it is possible to provide a venturi tube that can improve energy saving.
(2) A part of the pulse jet (compressed air) injected during backwashing of the filter cloth is ejected from the opening of the peripheral wall portion in the radial direction (outer peripheral direction) of the retainer, and the negative pressure generated on the upper end side of the retainer is generated. By reducing, it is possible to provide a venturi tube that can alleviate the strong attraction of the filter cloth on the upper end side of the retainer, prevent the filter cloth from being damaged, and improve the life of the filter cloth.
(3) Compressed air injected from the nozzle during backwashing can be evenly ejected from the plurality of openings arranged on the circumference of the peripheral wall toward the outer periphery of the retainer, and partially on the outer periphery of the peripheral wall Negative pressure can be prevented, the filter cloth on the upper end of the retainer can be surely inflated all around, the negative pressure reduction effect is uniform, and the dust of the bag filter retainer Therefore, it is possible to provide a highly reliable Venturi tube that can improve the efficiency of the dust removal and can keep the dust removal efficiency substantially constant.

According to invention of Claim 2, in addition to the effect of Claim 1,
(1) During backwashing, compressed air can be ejected from a plurality of openings arranged in a staggered pattern on the peripheral wall portion, and the filter cloth on the upper end side of the retainer regardless of the circumferential direction or longitudinal position of the peripheral wall portion It is possible to provide a venturi tube that can be uniformly inflated outwardly without unevenness, has excellent dust dusting efficiency and uniformity, and has excellent filtration performance.

According to invention of Claim 3, in addition to the effect of Claim 1 or 2,
(1) Reliability that can secure the flow path cross-sectional area of the upper end of the retainer by the flange opening formed in the flange, and can prevent an increase in the load of the blower used for suction during dust collection; It is possible to provide a venturi tube excellent in energy saving.
(2) The flange opening has a tapered inner peripheral surface formed by expanding from the upper end side toward the lower end side, thereby reducing pressure loss caused by suction of the blower during dust collection. The load of the blower can be reduced and energy saving is excellent, and the reliability of the negative pressure improvement effect can be improved by suppressing the generation of negative pressure after pulse jet injection during backwashing, and the efficiency of dust removal In addition, it is possible to provide a venturi tube having excellent filtration performance.

According to invention of Claim 4,
(1) A part of the compressed air injected during the backwashing of the filter cloth can be ejected from the opening of the peripheral wall portion in the radial direction of the retainer, so that the negative pressure generated at the upper end side of the retainer can be reduced. The entire filter cloth including the filter cloth is inflated outwards to ensure that the dust adhering to the filter cloth can be surely wiped out, and it has excellent reliability of maintenance, increases the effective filtration area during dust collection, and improves dust collection efficiency. In addition, it is possible to provide a bag filter retainer that can prevent the filter cloth from being strongly attracted on the upper end side of the retainer to prevent the filter cloth from being damaged, and has a long life span of the filter cloth. .
(2) Since the flange opening is formed in the flange, the flow path cross-sectional area of the retainer upper end can be secured, and the increase in the load of the blower used for suction during dust collection is prevented. It is possible to provide a bug filter retainer that is excellent in energy saving.
(3) By attaching a venturi tube to reduce the generation of negative pressure due to pulse jet (compressed air) during backwashing, the entire filter cloth including the upper end of the retainer body can be reliably inflated outward. Therefore, it is possible to provide a bug filter retainer that can improve the dust removal effect, is excellent in maintainability and energy saving, and has excellent filtration performance.

The best mode for carrying out the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 1 is a cross-sectional front view of a venturi tube according to Embodiment 1 of the present invention, FIG. 2 (a) is a plan view of the venturi tube according to Embodiment 1 of the present invention, and FIG. It is AA sectional view taken on the line.
1 and 2, 1 is a venturi tube according to the first embodiment of the present invention, 2 is a cylindrical peripheral wall portion of the venturi tube 1, 2a is a lower end opening portion of the venturi tube 1, and 2b is an upper end opening portion of the venturi tube 1. Reference numeral 3a denotes four openings of the venturi tube 1 arranged at equal angular intervals on the circumference on the upper end side in the longitudinal direction of the peripheral wall portion 2, and reference numeral 3b denotes a circumference on the lower end side in the longitudinal direction of the peripheral wall portion 2 Four elongated openings 4a of the venturi tube 1 arranged alternately in a staggered manner with the openings 3a at equal angular intervals, 4a is formed by cutting the peripheral wall 2 to form the openings 3a. The peripheral wall guide part 4b as a guide part of the opening part 3a formed integrally with the peripheral wall part 2 by bending at the lower end part to the inner peripheral side of the peripheral wall part 2 at the attachment angle α ₁ corresponds to the position of the opening part 3b. A plurality of (four places) guide portions 5 and a substantially cross-shaped central opening 5a A bottom guide portion as a guide portion of the opening 3b which is formed in an annular shape and is fixed to the lower end portion on the inner peripheral side of the peripheral wall portion 2 by welding at an attachment angle α ₂ = 90 °, and 6 is the upper end side of the peripheral wall portion 2 A flange portion of the venturi tube 1 disposed on the outer periphery of the venturi tube 6a, a locking portion for fixing the venturi tube 1 formed in a substantially U shape on the outer periphery of the flange portion 6 and locked to a partition plate (cell plate) of the dust collector, Reference numeral 7 denotes eight circular flange opening portions formed at equal angular intervals on the circumference of the flange portion 6, and 7 a is formed by expanding from the upper end side to the lower end side of the flange portion opening portion 7. It is the taper-shaped inner peripheral surface made.

FIG. 3 is a cross-sectional front view of an essential part of the bag filter retainer provided with the venturi pipe according to Embodiment 1 of the present invention.
In FIG. 3, 10 is a bag filter retainer in which the venturi tube 1 according to the first embodiment is inserted in the center of the upper end side of the retainer body 11, and 12 is formed annularly with a metal wire such as stainless steel. A plurality of retaining rings 11 of the retainer body 11 arranged at predetermined intervals, 13 is a retainer body 11 formed of a metal wire such as stainless steel and joined by spot welding or the like on the circumference of the outer periphery side of the securing ring 12. A plurality of vertical wire members 20 are a partition plate (cell plate) of the dust collector to which the fixing locking portion 6a of the venturi tube 1 is locked.
In addition, although the filter cloth formed in the cylinder shape etc. is arrange | positioned at the outer periphery of the retainer main body 11, it abbreviate | omitted on account of description.

  The openings 3a and 3b are arranged in a staggered manner in two upper and lower stages on the circumference of the peripheral wall portion 2 at four equal angular intervals. Thereby, the opening area can be increased without reducing the strength of the peripheral wall portion 2, compressed air can be jetted from the entire surface of the peripheral wall portion 2 during backwashing, and the vicinity of the position where the venturi pipe 1 is attached. The negative pressure generated in the negative pressure generation region can be effectively reduced, and dust can be reliably removed from the upper end side of the retainer body 11. In particular, by arranging the openings 3a and 3b at equal angular intervals on the circumference of the peripheral wall 2 of the venturi tube 1, the flow of the air flow ejected from the peripheral wall 2 extends over the entire outer periphery of the peripheral wall 2. It becomes uniform, and dust can be removed without unevenness, and the stability of filtration performance can be improved. In addition, since the opening 3b is formed in a long hole shape to ensure a sufficient opening area, clean air sucked by a blower (not shown) during dust collection passes through the opening 3b and enters the interior of the venturi tube 1. It becomes easy to enter the blower and the load on the blower can be reduced.

The shape, number, area, arrangement, and the like of the openings 3a, 3b are not limited to the present embodiment, and the diameter of the retainer body 11 of the bag filter retainer 10, the diameter and the length of the venturi tube 1 are not limited. It can be appropriately selected depending on the above.
The number of openings 3a and 3b is preferably 3 to 6. As the number of the openings 3a and 3b becomes smaller than three, the compressed air ejected from the peripheral wall portion 2 is easily biased, and the filter cloth in the vicinity of the outer periphery of the peripheral wall portion 2 becomes difficult to swell uniformly. There is a tendency that the dust removal effect at the upper end tends to be insufficient, and the amount of compressed air that passes through the interior of the venturi tube 1 and reaches the lower end of the retainer main body 11 tends to be insufficient as the number of dust increases more than six. This is because it has been found that the dust removal effect on the lower end side of the retainer body 11 tends to be insufficient.
The number of stages in which the openings 3 a and 3 b are arranged can be appropriately selected according to the length of each of the openings 3 a and 3 b and the total length of the peripheral wall 2. In the case where a plurality of openings 3a and 3b are arranged, the length of the openings 3a and 3b for each stage may be different as in the present embodiment, or may be the same. Further, the lengths of the openings 3a and 3b in each stage do not have to be the same. For example, the openings 3a and 3b having two kinds of lengths can be alternately arranged on the circumference.

The attachment angle α ₁ formed by the upper end side of the peripheral wall portion 2 and the peripheral wall guide portion 4a can be appropriately selected within a range of 30 degrees to 90 degrees. As the mounting angle α ₁ of the peripheral wall guide part 4a becomes smaller than 30 degrees, the interval between the opening part 3a and the peripheral wall guide part 4a becomes narrower, and it becomes difficult for the compressed air to be ejected from the opening part 3a, and it is ejected from the opening part 3a Compressed air does not spread in the radial direction (outer peripheral direction) of the retainer main body 11 but easily flows to the lower end side of the retainer main body 11, and the filter cloth on the upper end side of the retainer main body 11 (outer periphery of the peripheral wall portion 2) is expanded outward. As the angle becomes larger than 90 degrees, the compressed air hitting the peripheral wall guide 4a cannot be guided to the opening 3a, and the compressed air passes through the inside of the venturi tube 1 as it is. This is because it tends to flow to the lower end side of the retainer 11 and it is difficult to swell the filter cloth on the upper end side (the outer periphery of the peripheral wall portion 2) of the retainer body 11 outward.
The peripheral wall guide portion 4a may be attached to the lower end portion of each opening 3a by a flat plate member by welding or screwing, in addition to being formed integrally with the peripheral wall portion 2, In some cases, a plurality of guides can be connected to each other at the base (base side) to form an annular shape.

In the present embodiment, as the guide portion corresponding to the opening portion 3b, the bottom guide portion 4b having the central opening portion 5a and integrally formed with the plurality of guide portions 5 is used, but it corresponds to each opening portion 3b. A plurality of guide portions 5 may be provided separately and separately. Further, like the guide portion 4a, a part of the peripheral wall portion 2 can be bent and formed integrally with the peripheral wall portion 2.
In addition, although the attachment angle α ₂ formed by the upper end side of the peripheral wall portion 2 and the guide portion 5 of the bottom guide portion 4b is set to 90 degrees, it is in the range of 30 to 90 degrees similarly to the attachment angle α ₁ of the peripheral wall guide portion 4a. It can select suitably. Further, the opening area and shape of the central opening 5a can be appropriately selected according to the inner diameter of the venturi tube 1 and the number of openings 3b formed in the peripheral wall 2. From the opening 3b to the retainer main body 11 This is determined in consideration of the balance between the amount of compressed air to be ejected to the outer periphery and the amount of compressed air to be ejected from the central opening 5a to the lower end side of the retainer body 11.

The shape, number, arrangement, and the like of the flange opening 7 can be appropriately selected according to the diameter of the retainer body 11 of the bag filter retainer 10, the diameter of the venturi tube 1, and the like.
As the shape of the flange opening 7, an elliptical shape such as an elliptical shape is suitably used in addition to the circular shape. The opening area (total area) of the flange opening 7 is 3% to 8% of the cross-sectional area of the retainer body 11 although it depends on the shape and area of the peripheral wall guide 4a and the bottom guide 4b. As the opening area (total area) of the flange opening 7 becomes smaller than 3% of the cross-sectional area of the retainer main body 11, the load of the blower used for suction during dust collection tends to increase, more than 8%. As a result, when a pulse jet is ejected when dust is removed, an attracting force is generated between the positive pressure in the filter cloth by the pulse jet and the suction negative pressure of the blower on the upper part of the partition plate (cell plate). 11, the negative pressure reduction effect at the upper end of the retainer 11 becomes insufficient, and the positive pressure of the pulse jet does not reach the lower end of the retainer main body 11, and dust tends to be insufficiently discharged at the lower end of the retainer main body 11. It is because it was found that there is.
In addition, by arranging the flange opening 7 on the circumference of the flange 6 at equal angular intervals, the flow of clean air sucked by the blower becomes uniform over the entire outer periphery of the peripheral wall 2, and the filter cloth Filtration can be performed efficiently without unevenness on the entire surface, and the stability of filtration performance is excellent.

A method for using the bag filter retainer including the venturi tube according to the first embodiment of the present invention configured as described above will be described below.
FIG. 4 (a) is a schematic cross-sectional view of the main part showing the state of the filter cloth during dust collection of the bag filter retainer provided with the venturi tube in Embodiment 1 of the present invention, and FIG. 4 (b) is the present invention. It is a principal part schematic cross section which shows the state of the filter cloth at the time of backwashing of the bag filter retainer provided with the venturi pipe | tube in the first embodiment.
In FIG. 4, 25 is a cylindrical filter cloth disposed on the outer periphery of the retainer body 11, and 30 a is a pulse jet type disposed above the bag filter retainer 10 and injects compressed air into the retainer body 11. This is the nozzle of the payout mechanism 30.

At the time of dust collection, as shown in FIG. 4A, a dust-containing air flow flows into the filter cloth 25 from the outside of the filter cloth 25, dust is collected on the outer periphery of the filter cloth 25, and dust is separated and collected. The cleaned clean airflow is discharged through the upper end opening 2 b of the venturi tube 1 on the upper end side of the retainer body 11 and the flange portion opening 7 of the flange portion 6. At this time, the clean airflow moving from the lower end side of the retainer main body 11 to the upstream side can smoothly move along the peripheral wall portion 2 of the venturi tube 1, and the venturi tube 1 does not hinder the flow of the airflow. .
When backwashing is performed at regular intervals, as shown in FIG. 4B, compressed air is jetted from the nozzle 30a of the scraping mechanism 30 toward the inside of the retainer body 11 (inside the filter cloth 25). . At this time, the compressed air that has entered from the upper end opening 2 b of the venturi pipe 1 moves toward the lower end side of the retainer body 11 through the lower end opening 2 a, but a part of the compressed air is inside the venturi pipe 1. Generation of negative pressure is reduced by striking against the guide portions 5 of the peripheral wall guide portion 4a and the bottom guide portion 4b and ejecting from the openings 3a, 3b in the radial direction (outer peripheral direction) of the retainer main body 11, thereby reducing the generation of the retainer main body 11. The filter cloth 25 on the upper end side swells almost uniformly outward, and the dust adhering to the outer surface of the filter cloth 25 is instantaneously removed.
Further, the compressed air that passes through the central opening 5a of the bottom guide 4b, passes through the lower end opening 2a of the venturi tube 1 and reaches the lower end side of the retainer main body 11 moves toward the lower end side of the retainer main body 11. The filter cloth 25 can be sequentially inflated in between, and the dust adhering to the outer surface over the entire length of the filter cloth 25 can be surely removed.

As described above, since the venturi tube according to the first embodiment of the present invention is configured, the following operation is obtained.
(1) A plurality of openings 3a and 3b formed on the circumference of the peripheral wall 2, and a peripheral wall guide 4a and a peripheral wall projecting on the inner peripheral side of the peripheral wall 2 at the lower ends of the openings 3a and 3b And a bottom guide portion 4b provided with a plurality of guide portions 5 projecting to the inner peripheral side of the portion 2, so that when the filter cloth 25 is backwashed, it is compressed from the nozzle 30a disposed on the upper portion of the bag filter retainer 10. When air is injected, a part of the compressed air is guided by the guide part 5 of the peripheral wall guide part 4a and the bottom part guide part 4b, and from the openings 3a and 3b to the outer peripheral direction of the peripheral wall part 2 (in the radial direction of the retainer). The negative pressure generated on the upper end side of the retainer main body 11 can be reduced, the entire filter cloth 25 including the upper end side of the retainer main body 11 can be expanded outward substantially uniformly, The dust adhering to the cloth 25 can be surely removed, and the Excellent reliability of Maintenance Manual, it is possible to improve the dust collecting efficiency spread effective filtration area during dust collection, excellent energy saving properties.
(2) When the filter cloth 25 is backwashed, a part of the compressed air sprayed from the nozzle 30a disposed on the upper part of the bag filter retainer 10 is passed through the openings 3a and 3b in the radial direction (peripheral direction) of the retainer body 11. By reducing the negative pressure generated on the upper end side of the retainer main body 11, the filter cloth 25 is strongly attracted on the upper end side of the retainer main body 11, and the sticking to the retainer main body 11 can be reduced. Further, the filter cloth 25 can be prevented from being damaged, and the life of the filter cloth 25 can be improved.
(3) By arranging a plurality of openings 3a and 3b on the circumference of the peripheral wall portion 2, compressed air injected from the nozzle 30a during backwashing from the entire periphery of the peripheral wall portion 2 to the outer peripheral side of the retainer body 11 The filter cloth 25 on the upper end side of the retainer body 11 can be surely inflated outward over the entire circumference, and dust can be efficiently removed to remove dust. Can be kept substantially constant.
(4) By arranging the plurality of openings 3a and 3b on the circumference of the peripheral wall portion 2, it is possible to prevent a negative pressure from being partially generated on the outer periphery of the peripheral wall portion 2, and to make the negative pressure reduction effect uniform. It is excellent in that the dust can be surely removed, and the reliability of the filtration performance and the long life of the filter cloth are excellent.
(5) By disposing a plurality of openings 3a, 3b in the longitudinal direction of the peripheral wall 2, compressed air injected from the nozzle 30a during backwashing from the openings 3a, 3b almost all over the outer periphery of the peripheral wall 2. It can be ejected toward the outer peripheral side of the retainer main body 11, the filter cloth 25 on the upper end side of the retainer main body 11 can be surely inflated outward over the entire length of the negative pressure generating region, and dust can be removed. Can be performed efficiently.
(6) Since the plurality of openings 3a and 3b are arranged in a staggered manner on the peripheral wall 2, the compressed air injected from the nozzle 30a during backwashing is positioned in the circumferential or longitudinal direction of the peripheral wall 2. Regardless of this, the openings 3a and 3b can be reliably ejected toward the outer peripheral side of the retainer main body 11, and the filter cloth 25 on the upper end side of the retainer main body 11 can be uniformly inflated outward without any spots. Excellent dust removal efficiency and filtration performance reliability.
(7) By disposing the peripheral wall guide portion 4a and the bottom guide portion 4b on the inner peripheral side of the peripheral wall portion 2, the internal resistance of the venturi tube 1 increases and the flow path cross-sectional area decreases, but the flange portion 6 By forming the flange opening 7 on the top, the flow passage cross-sectional area of the upper end of the retainer body 11 can be secured, and an increase in the load of the blower used for suction during dust collection can be prevented. Excellent in properties.
(8) Since the flange opening 7 has a tapered inner peripheral surface 7a formed to expand from the upper end side toward the lower end side, pressure loss caused by suction of the blower during dust collection can be reduced. It can reduce the load of the blower and reduce the negative pressure after the pulse jet injection during backwashing, improve the negative pressure improvement effect, improve the efficiency of dust removal, the filtration performance Reliability can be improved.

As described above, the bag filter retainer including the venturi tube according to the first embodiment of the present invention is configured, and thus the following operation is obtained.
(1) Since the venturi tube 1 is inserted and disposed at the center of the upper end side of the retainer body 11, one of the compressed air injected from the nozzle 30a on the retainer body 11 when the filter cloth 25 is backwashed. Can be ejected in the radial direction of the retainer main body 11 from the openings 3a and 3b provided in the peripheral wall portion 2 of the venturi tube 1, and the negative pressure generated on the upper end side of the retainer main body 11 can be reduced. The entire filter cloth 25 including the upper end side of the filter is inflated outwardly, so that dust adhering to the filter cloth 25 can be surely removed, and the effective filtration area at the time of dust collection is widened to improve dust collection efficiency. In addition, the filter cloth 25 can be prevented from being strongly attracted at the upper end side of the retainer body 11 to prevent the filter cloth 25 from being damaged, and the filter cloth 25 has a long life.
(2) Since the venturi tube 1 having the flange portion opening 7 in the flange portion 6 is inserted and disposed at the center portion on the upper end side of the retainer body 11, the flow path disconnection at the upper end portion of the retainer body 11 is achieved. The area can be expanded as compared with a conventional venturi tube, the load of the blower used for suction during dust collection can be reduced, and energy saving is excellent.
(3) The suction negative pressure by the blower during dust collection increases at the upper end of the retainer main body 11, so that the amount of dust adhering to the upper end increases, but the venturi having openings 3a and 3b in the peripheral wall 2 By reducing the generation of negative pressure due to pulse jet (compressed air) during backwashing by attaching the tube 1, the effect of dust removal on the upper end side of the retainer body 11 can be improved, and energy saving and reliability of filtration performance can be improved. Excellent in properties.

Hereinafter, the present invention will be specifically described by way of examples.
(Example 1)
The pressure measurement during backwashing was performed by the bag filter retainer provided with the venturi tube described in the first embodiment.
The bag filter retainer 10 used for pressure measurement has a retainer body 11 diameter of 160 mm, a retainer body 11 length of 9000 mm, a venturi pipe 1 length of 130 mm, a venturi pipe 1 peripheral wall 2 diameter (inner diameter) of 57.5 mm, a flange The hole diameter (minimum diameter) of the part opening 7 was set to 13 mm, and the opening area (total area) of the flange part opening 7 was formed to be about 5% of the cross-sectional area of the retainer body 11 (see FIG. 3).
A 294 kPa pulse jet (compressed air) is jetted from the nozzle 30a of the pulse jet type wiper mechanism 30 to the bag filter retainer 10 for 0.2 seconds, and 200 mm, 350 mm, and 3000 mm are respectively provided from the upper end of the bag filter retainer 10. The pressure was measured at the position (see FIG. 4).
In addition, the digital fine differential pressure gauge (the Nagano Keiki Co., Ltd. make, model number GC62) was used for the measurement of a pressure. The pressure range (measurement range) was set to -5 kPa to 5 kPa, and the graph was created by displaying the measured value by the comparator output (response: within 5 ms) and analog output (response: within 50 ms). In addition, the maximum pressure and the minimum pressure applied to the pressure port were stored in the internal memory as a peak value and a bottom value by the peak hold function of the digital differential pressure gauge.

(Example 2)
In FIG. 4, the pressure was measured in the same manner as in Example 1 except that the pressure of the pulse jet (compressed air) ejected from the nozzle 30a was changed to 490 kPa.

(Comparative Example 1)
In FIG. 5, instead of the venturi tube 1, pressure was applied in the same manner as in Example 1 except that a conventional venturi tube 52 (see Japanese Patent Laid-Open Nos. 10-2111410 and 8-299732) was attached. It was measured.
5 is the same as the retainer body 11 and the removal mechanism 30 in FIG. 4, and only the venturi tube 52 is different.

(Comparative Example 2)
In FIG. 5, the pressure was measured in the same manner as in Comparative Example 1 except that the pressure of the pulse jet (compressed air) injected from the nozzle 70a was changed to 490 kPa.

6 to 9 are views showing the measurement results of pressure. 6 to 9, the horizontal axis indicates time, and the vertical axis indicates pressure. On the graph, the part exceeding the display range (± 1.25 kPa) is cut, and there are some peak values that could not follow the response of the analog output. And the maximum negative pressure are values of the maximum pressure (peak value) and the minimum pressure (bottom value) stored in the internal memory of the digital fine differential pressure gauge, respectively, and there is no problem in measurement.
According to the measurement results in Comparative Example 1 in FIGS. 6A to 6C and the measurement results in Example 1 in FIGS. 7A to 7C, the retainer body 11 in the conventional Comparative Example 1 is shown. On the upper end side (l = 200 mm, 350 mm), a maximum negative pressure of about 1 kPa was generated (see FIGS. 6A and 6B), whereas in Example 1, the upper end side of the retainer body 11 was (L = 200 mm, 350 mm), only a negative pressure of 0.44 to 0.45 kPa, which is less than half that of Comparative Example 1, is generated (see FIGS. 7A and 7B), and backwashing is performed reliably. Thus, it became clear that dust adhering to the filter cloth 25 can be removed.
Further, in a region other than the negative pressure generation region on the upper end side of the retainer body 11 (l = 3000 mm), a sufficient positive pressure is obtained in any of Comparative Example 1 in FIG. 6C and Example 1 in FIG. 7C. It was revealed that it was consistent with the dust removal situation.

In Comparative Example 1 as well, when a pulse jet (compressed air) is injected, positive pressure is generated for an instant (about 0.02 seconds) on the upper end side (l = 200 mm, 350 mm) of the retainer body 11. (See FIGS. 6 (a) and 6 (b)) However, since the time is short, the filter cloth 55 does not react, remains in the suction state, and it is clear that dust cannot be removed. .
The filter cloth 55 is always sucked by the blower, and even if a positive pressure pulse jet (compressed air) is injected at regular intervals, the injection speed is high (about 90 m / s), and the positive pressure is generated. Only for a moment (about 0.02 seconds), the filter cloth 55 cannot react and remains in the suction state, and because of the negative pressure generated by the compressed air repeatedly injected, the filter cloth 55 Is strongly attracted to the retainer main body 51 and is easily rubbed and damaged, leading to a reduction in the life of the filter cloth 55.
In addition, the pressure in the steady state after a sufficient time has elapsed from the injection of the pulse jet (compressed air) indicates the suction pressure of the blower. In Comparative Examples 1 and 1, the pressure is -0.12 to -0.11 kPa. It became clear that there was no change in the load of the blower and there was no difference in the suction efficiency.

According to the measurement result in Comparative Example 1 in FIGS. 6A to 6C and the measurement result in Comparative Example 2 in FIGS. 8A to 8C, the conventional Venturi tube 52 (see FIG. 5) is formed. With the attached one, when the pressure of the pulse jet (compressed air) is increased, the positive pressure increases at a position away from the negative pressure generation region on the upper end side of the retainer body 11 (l = 3000 mm) (FIG. 6 ( c) and FIG. 8 (c)), on the other hand, the maximum negative pressure is increased more than twice on the upper end side (1 = 200 mm, 350 mm) of the retainer body 11 (FIGS. 6A and 6B). 8), FIG. 8 (a) and FIG. 8 (b)), it became clear that the filter cloth 25 was strongly attracted to the retainer body 11 and was easily damaged.
On the other hand, according to the measurement results in Example 1 of FIGS. 7A to 7C and the measurement results in Example 2 of FIGS. 9A to 9C, the first embodiment of the present invention is shown. In the case where the venturi tube 1 is attached, even if the pressure of the pulse jet (compressed air) is increased, the increase in the maximum negative pressure on the upper end side (l = 200 mm, 350 mm) of the retainer body 11 is about 0.1 kPa. (Refer to FIGS. 7 (a), (b), 9 (a) and 9 (b)), negative pressure improvement effect and dust removal on the upper end side (1 = 200 mm, 350 mm) of the retainer body 11 The drop effect became clear.
The phenomenon in which negative pressure is generated at the upper end side of the retainer body as seen in Comparative Examples 1 and 2 is the same phenomenon as that of a retainer not equipped with a venturi tube (however, the magnitude and distribution of the negative pressure are different). It is clear that this can be improved by installing the venturi tube of the present invention.

According to the present invention, a part of the compressed air injected from the nozzle disposed above is ejected from an opening formed in the peripheral wall portion of the venturi tube, and the negative pressure generated near the outer periphery of the venturi tube can be alleviated. The entire filter cloth including the upper end side of the retainer can be inflated outwards, and dust attached to the filter cloth can be surely removed, and the effective filtration area can be expanded and the dust collection efficiency can be improved. At the same time, it is possible to provide a venturi tube excellent in long-life filter cloth and a bag filter retainer having the filter cloth that can prevent the filter cloth from being damaged by relaxing the sticking of the filter cloth on the upper end side of the retainer. Therefore, it is possible to improve the filtration efficiency of the existing dust collector and extend the life of the filter cloth, thereby contributing to resource saving and energy saving.

Sectional front view of the venturi pipe in Embodiment 1 of this invention (A) Plan view of a venturi tube according to the first embodiment of the present invention (b) Cross-sectional view taken along line AA in FIG. The top view of the retainer for bag filters provided with the venturi pipe in Embodiment 1 of this invention (A) Schematic sectional view showing a state of a filter cloth at the time of dust collection of the bag filter retainer provided with the venturi pipe according to the first embodiment of the present invention (b) The venturi pipe according to the first embodiment of the present invention Schematic cross-sectional view of the relevant part showing the state of the filter cloth during backwashing of the bag filter retainer (A) A schematic cross-sectional view showing the state of a filter cloth during dust collection of a conventional bag filter retainer in a dust collector equipped with a pulse jet type wiper mechanism. (B) A pulse jet type wiper mechanism is provided. Schematic cross-sectional view of the main part showing the state of the filter cloth when dust is removed from the conventional bag filter retainer in the dust collector (backwashing) Figure showing pressure measurement results Figure showing pressure measurement results Figure showing pressure measurement results Figure showing pressure measurement results

Explanation of symbols

1,52 Venturi tube 2 peripheral wall 2a lower end opening 2b upper end opening 3a, 3b opening 4a peripheral wall guide 4b bottom guide 5 guide 5a central opening 6, 52a flange 6a fixing lock 7 flange Opening 7a Inner circumferential surface 10, 50 Bag filter retainer 11, 51 Retainer body 12 Fixing ring 13 Vertical wire 20, 60 Partition plate (cell plate)
25, 55 Filter cloth 30, 70 Draw-off mechanism 30a, 70a Nozzle

Claims (4)

A venturi tube that is inserted and disposed in a central portion on the upper end side of the bag filter retainer, the plurality of openings formed on a circumference of the peripheral wall portion, and the peripheral wall at a lower end portion of the opening portion And a guide part disposed on the inner peripheral side of the part. The venturi tube according to claim 1, wherein the plurality of openings are arranged in a staggered pattern on the peripheral wall portion. A flange portion disposed on the outer periphery of the upper end of the peripheral wall portion; and a flange portion opening portion having a tapered inner peripheral surface that is formed on the flange portion and is expanded from the upper end side toward the lower end side. The venturi tube according to claim 1 or 2, further comprising: A retainer body including a plurality of fixing rings formed in a ring shape with a metal wire and arranged at predetermined intervals, and a plurality of vertical wires joined to the outside of the fixing ring, and a center on the upper end side of the retainer body A bug filter retainer comprising: the venturi tube according to any one of claims 1 to 3, wherein the bag filter tube is inserted into the portion.

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