KR20240070050A - Integrated bag-cage unit and dust collector having the same - Google Patents

Abstract

The present invention includes a back cage forming the frame of a bag filter, an upper venturi disposed at the top of the back cage to introduce a pulse jet generated from an injector, and a venturi disposed spaced downward from the upper venturi and passing through the upper venturi. Disclosed is an integrated backcage unit including a lower venturi configured to increase the flow rate by guiding a pulse jet into a narrow through hole.

Description

Integrated bag cage unit and filter dust collector equipped with the same {INTEGRATED BAG-CAGE UNIT AND DUST COLLECTOR HAVING THE SAME}

The present invention relates to an integrated backcage unit and a filter dust collector having the same. More specifically, the present invention relates to an integrated backcage unit, which increases the flow rate reaching the bottom of the bag filter by controlling the longitudinal flow rate of the bag filter, thereby increasing dust removal efficiency. It relates to a filter dust collector equipped with an integrated back cage unit that can improve and reduce operating costs.

In thermal power plants or workplaces where a lot of dust is generated, dust collection equipment is applied to collect particulate matter and dust contained in exhaust gas or process gas and discharge purified air.

These dust collection facilities are mainly equipped with filter dust collectors using bag filters. Bag filters, cartridge filters, and candle filters made of non-woven fabric or ceramic are used in filter dust collectors. However, these filters have the disadvantage that when used for a long time, dust or emissions are adsorbed on the outer surface of the filter, increasing back pressure and reducing filtration efficiency. Therefore, a dedusting process is necessary to shake off foreign substances adsorbed on the filter by periodically spraying a pulse jet (compressed air) in a direction opposite to the filtration direction of the filter.

In order to improve the efficiency of this desorption process, Republic of Korea Patent No. 10-1309025 'Venturi for dust collector' (hereinafter referred to as 'Patent Document 1') attempted to increase desorption efficiency by changing the structure of the venturi at the top of the bag filter. . Specifically, in Patent Document 1, a spiral groove, etc. is formed on the inner peripheral surface of the venturi that guides compressed air to the bag filter, so that the compressed air discharged from the blower tube moves downward efficiently when flowing in the venturi, removing foreign substances bound to the bag filter. We present a structure that makes it possible.

In Republic of Korea Patent No. 10-0776693, 'Compressed air injection device for dust collector bag filter using multiple venturi structure' (hereinafter referred to as 'Patent Document 2'), a space capable of sucking air is formed directly around the venturi. A structure is proposed in which a plurality of such venturis are installed in a layered structure to increase air suction and improve the desorption effect of the bag filter.

However, since the bag filter used in the field has a length of several meters (m), it is difficult to actually deliver the pulse jet (compressed air) to the bottom of the filter simply by changing the upper venturi structure. As a result, as time goes by, the difference in dust collection performance between the upper and lower parts of the bag filter occurs, and the problem that the filter's efficiency and lifespan is shortened continues to be raised.

Republic of Korea Patent No. 10-1309025 Republic of Korea Patent No. 10-0776693

The present invention is intended to solve the above problems, and its purpose is to provide a filter dust collector that can increase dust removal efficiency by adjusting the longitudinal flow rate of the bag filter by applying an integrated bag cage unit.

In addition, the purpose of the present invention is to provide a filter dust collector that can reduce air pollution by applying a bag filter with improved dust removal efficiency, extending the life of the filter, saving time required for maintenance, and increasing dust collection efficiency. .

In order to solve the above problems, the present invention includes a back cage forming the frame of a bag filter, an upper venturi disposed at the top of the back cage to introduce the pulse jet generated from the injector, and spaced downward from the upper venturi. Disclosed is an integrated back cage unit including a lower venturi that is disposed and formed to increase the flow rate by guiding the pulse jet that has passed through the upper venturi to a narrow through hole.

According to one embodiment of the present invention, the lower venturi includes a flat member extending in the width direction, a first inclined surface member extending from an inner end of the flat member to form an inclined surface inclined inward, and an end of the inclined surface member. Discloses an integrated back cage unit comprising a cylindrical member extending downward and a second inclined surface member extending from an end of the cylindrical member to form an outwardly inclined inclined surface.

According to one embodiment of the present invention, an integrated back cage unit is disclosed, wherein the lower venturi is located at 1/3 of the back cage.

According to one embodiment of the present invention, an integrated back cage unit is disclosed, wherein the diameter of the center hole of the flat member is less than 2/3 of the diameter of the center hole of the upper venturi.

According to one embodiment of the present invention, an integrated back cage unit is disclosed, further comprising a flow control unit formed on the inner surface of the cylindrical member to control pulse jet flow.

According to one embodiment of the present invention, the flow control unit discloses an integrated back cage unit characterized in that it includes eight flow protrusions arranged at equal intervals.

According to one embodiment of the present invention, the flow protrusion includes a vertical protrusion extending in the vertical direction, a lower protrusion protruding from the lower end of the vertical protrusion in one direction, and an upper protrusion protruding from the upper end of the vertical protrusion in the other direction. Disclosed is an integrated back cage unit characterized in that:

According to an embodiment of the present invention, an integrated back cage unit is characterized in that the area (B) of the space between adjacent flow projections is 40% to 60% of the area (A) of the flow projections when viewed from the top. Begin.

According to one embodiment of the present invention, the upper surface of the lower protrusion includes a recessed surface and a protruding surface, and an inflection line whose curvature changes from positive to negative is formed between the recessed surface and the protruding surface. Start the backcage unit.

According to one embodiment of the present invention, the upper surface of the lower protrusion includes a recessed surface and a protruding surface, and an inflection line whose curvature changes from positive to negative is formed between the recessed surface and the protruding surface, and the upper surface of the upper protrusion Discloses an integrated back cage unit characterized by comprising a left curved surface and a right curved surface curved downward.

According to the present invention, the integrated back cage unit causes the surrounding air to flow into the primary venturi due to the pressure difference between the compressed air and the compressed air discharged from the blow tube, causing primary exhaustion, and reducing the existing flow rate through the secondary venturi. By adjusting the flow rate and pressure, the flow rate and pressure are reduced by 20 to 30% compared to the conventional back cage. It can be improved.

In addition, according to the present invention, by increasing the flow rate and pressure at the bottom of the bag filter during the dedusting process, the desorption efficiency in a long bag filter can be improved, and it is possible to reduce the facility cost and operating cost of the filter dust collector.

1 is a diagram showing a filter dust collector according to an embodiment of the present invention.
Figure 2 is a diagram showing an integrated back cage unit according to an embodiment of the present invention.
FIG. 3 is a diagram showing the connection relationship between the upper venturi and the lower venturi shown in FIG. 2.
Figure 4 is a front view of the lower venturi according to one embodiment (Example 1) of the present invention.
Figure 5 is a plan view of the lower venturi shown in Figure 4.
Figure 6 is a bottom view of the lower venturi shown in Figure 4.
Figure 7 is a perspective view of a lower venturi according to another embodiment (Example 2) of the present invention.
Figure 8 is a plan view of the lower venturi shown in Figure 7.
Figure 9 is a bottom view of the lower venturi shown in Figure 7.
FIG. 10 is an enlarged conceptual diagram of the flow protrusion of the lower venturi shown in FIG. 7.
Figure 11 is a comparative example (Comparative Example 1) when the shape of the flow protrusion is modified.
Figure 12 is a comparative example (Comparative Example 2) when the spacing of flow protrusions is modified.
Figure 13 is flow rate experiment comparison data between a conventional back cage and a back cage according to embodiments of the present invention.
Figure 14 is a diagram showing pulse jet flow according to lower venturi structures.
Figure 15a shows flow rate experimental comparison data between the back cage according to an embodiment of the present invention and the back cage according to Comparative Example 1.
Figure 15b is flow rate experimental comparison data between the back cage according to an embodiment of the present invention and the back cage according to Comparative Example 2.
Figure 15c is flow rate experimental comparison data between the back cage according to an embodiment of the present invention and the back cage according to Comparative Example 3.

Hereinafter, the present invention will be described in more detail with reference to the drawings. In this specification, the same or similar reference numbers are assigned to the same or similar components even in different embodiments, and the description is replaced with the first description. As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise.

In addition, when describing with reference to the accompanying drawings, identical components will be assigned the same reference numerals regardless of the reference numerals, and overlapping descriptions thereof will be omitted. In describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

1 is a diagram showing a filter dust collector according to an embodiment of the present invention.

When explained with reference to FIG. 1, the filter dust collector 100 includes a housing 110 having an internal space, a bag filter 120 installed to filter contaminated air flowing into the housing 110, and An injection pipe 132 is installed on the upper side of the bag filter 120 at a predetermined distance to receive compressed air through the pulse jet air supply unit 130 and sprays it, and is installed on one side of the injection pipe 132 to spray the compressed air. The bag filter 120 may be equipped with an injector 150 that injects compressed air in multiple stages.

The bag filter 120 is installed on the fixing plate 148 installed on the upper part of the housing 110.

The cross-section of the bag filter is circular, and an upper venturi (ventury, 122) is installed at the top of the bag filter (120).

The bag filter 120 is composed of a bag (120a) made of non-woven fabric, etc., and a back cage (120b) that forms the frame of the bag (120a).

The pulse jet air supply means 130 is installed at a rear end of the air header 134 for accumulating compressed air, a ball valve 138 connected to the connector 136, and the ball valve 138. It may include a pulse valve 140 that supplies compressed air to the pipe 132, and a connector 142 connecting the pulse valve 140 and the injection pipe 132.

One end of the injection pipe 132 is connected to the connector 142, and the other end is fixed to the inner wall of the housing 110 using a fastening member 160.

The filter dust collector 100 supplies pulse jet compressed air through the pulse jet air supply means 130 and the spray pipe 132. It is possible to clean dust attached to the outer surface of the bag filter 120 during the dedusting process using pulse jet compressed air.

There is a hood 102 at the bottom of the housing 110 through which air containing dust flows, and the air filtered through the bag filter 120 is discharged through the outlet 190 at the top of the housing 110. .

A funnel-shaped dust hopper (170) exists at the bottom of the housing 110, and a rotary valve 180 is installed at the bottom of the dust hopper (170).

According to one embodiment of the present invention, the bag is formed by an organic combination of the upper venturi disposed at the top of the back cage 120b and the lower venturi disposed near the center of the back cage 120b, preferably 1/3 from the top. It is possible to increase the hydraulic pressure and flow rate at the bottom of the filter 120.

Hereinafter, the structure and performance of the integrated back cage unit of the present invention will be described in detail with reference to FIGS. 2 to 15.

Hereinafter, the structure and performance of the integrated back cage unit of the present invention will be described in detail with reference to FIGS. 2 to 15.

Figure 2 is a diagram showing an integrated back cage unit according to an embodiment of the present invention, and Figure 3 is a diagram showing the connection relationship between the upper venturi 210 and the lower venturi 220 shown in Figure 2.

Referring to Figures 2 and 3, the integrated back cage unit may include a bag 120a, a cage 120b, a venturi unit 200, etc.

The venturi unit 200 includes an upper venturi 210 and a lower venturi 220 that are organically coupled to each other.

The upper venturi 210 includes a ring-shaped flat member 211, a first inclined surface member 212 extending downward from the flat member 211 and having a funnel-shaped inclined surface, and the first inclined surface member 212. ), a cylindrical member 213 extending downward from the end of the cylindrical member 213, and a second oblique member 214 extending outward from the end of the cylindrical member 213.

The center hole of the flat member 211 is arranged to face the injector 150. The pulse jet ejected from the injector 150 flows into the center hole of the flat member. The end of the flat member 211 may be bent downward and bent into a '┌' shape or a '┐' shape. The end of the cage can be inserted into the curved area to secure the upper surface of the cage.

Compressed air flowing in through the center hole of the flat member 211 moves downward along the inclined surface of the first inclined member 212. As it moves along the slope, the air gathers at the center and moves to the cylindrical member 213. The air passing through the cylindrical member 213 spreads outward along the second inclined member 214.

FIG. 4 is a front view of the lower venturi 220 according to an embodiment of the present invention, FIG. 5 is a top view of the lower venturi 220 shown in FIG. 4, and FIG. 6 is a front view of the lower venturi 220 shown in FIG. 4. This is the bottom view.

Like the upper venturi 210, the lower venturi 220 may include a flat member 221, a first oblique surface member 222, a cylindrical member 223, and a second oblique surface member 224.

Since the flat member 221 of the lower venturi 220 is disposed inside the cage, its outer diameter is smaller than that of the flat member of the upper venturi 210. The central hole of the lower venturi (220) flat member has a diameter of about 2/3 of the central hole of the upper venturi (210) flat member.

The first oblique surface member 222 of the lower venturi 220 is formed to have a greater slope than the first oblique surface member 212 of the upper venturi 210. That is, the first inclined surface member 222 of the lower venturi 220 has a lower height than the first inclined surface member 212 of the upper venturi 210, and the difference in width between the upper and lower parts is small.

The air that passes through the cylindrical member 223 of the lower venturi 220 spreads outward along the second inclined member 224.

Referring to FIG. 3, in area I, air flows from the wide center hole of the first member to the narrow passage of the third member, so the flow rate of the air flowing from area I to area II increases. And as it passes through area II and enters area III, the air spreads to the side and impacts the bag filter.

However, if the air pressure decreases in area III, pressure cannot be applied to the lower part of the bag filter, so in the present invention, the lower venturi 220 is disposed to disperse the air pressure.

Air passing through area III passes through area IV and proceeds to area V. The air flowing through the IV area to the V area increases in flow speed, enters the VI area, spreads to the side, and impacts the lower part of the bag filter.

Figure 7 is a perspective view of the lower venturi 220 according to another embodiment of the present invention, Figure 8 is a plan view of the lower venturi 220 shown in Figure 7, and Figure 9 is a lower venturi 220 shown in Figure 7. It is a bottom view, and FIG. 10 is an enlarged conceptual diagram of the flow protrusion of the lower venturi 220 shown in FIG. 7.

Referring to the drawings, a flow control unit 230 may be formed on the inner surface of the cylindrical member of the lower venturi 220. The flow control unit 230 may be made in various forms, but in order to achieve optimal efficiency, it is preferable to have the same shape and spacing as shown in FIGS. 7 to 10. That efficiency may decrease if the shape of the flow control unit 230 is different will be explained in detail below with reference to FIGS. 11 to 15.

Referring to FIGS. 7 to 10, the flow control unit 230 includes a plurality of flow protrusions spaced apart from each other at equal intervals.

The flow protrusion includes a vertical protrusion (231a) extending in the vertical direction and a lower protrusion (231b) protruding laterally from the lower end of the vertical protrusion (231a). Additionally, an upper protrusion protruding in the opposite direction to the lower protrusion 231b may be formed at the upper end of the vertical protrusion 231a.

According to one embodiment of the present invention, a recessed surface 231c is formed between the lower protrusion 231b and the vertical protrusion 231a, and the cross-section has a downwardly concave curve, and the recessed surface is formed on the outer surface of the lower protrusion 231b. A protruding surface 231d having a curvature in the opposite direction to the surface 231c is formed. In other words, there is an inflection line 231e whose curvature changes from positive to negative between the recessed surface 231c and the protruding surface 231d.

A right curved surface (231g) and a left curved surface (231h) are formed on the upper surface of the upper protrusion. Referring to FIG. 10, the right curved surface (231g) causes the air hitting the upper protrusion to go downward along the vertical protrusion (231a) without forming a vortex, and the left curved surface (231h) allows the descending air to flow along the vertical protrusion (231a). ) and creates a vortex in the space between the upper protrusions and allows air to be concentrated in the discharge area (d) between the first flow protrusions (231) and the second flow protrusions (232).

According to another embodiment of the present invention, the lower protrusion 231b may be formed to become wider as it moves away from the vertical protrusion 231a. As in the above embodiment, if the curvature changes and the width is designed to gradually become wider, it is possible to make the lateral flow of air more smooth. Additionally, the upper protrusion may be formed to become narrower as it moves away from the vertical protrusion 231a.

As a result of numerous experiments, when applying the shape of the flow protrusion, the efficiency is best when the space (B) between adjacent flow protrusions on the plan view is between 40% and less than 60% of the area (A) formed by the flow protrusion. This was confirmed (see Figure 9). Hereinafter, it will be described in detail with reference to FIGS. 11 to 15.

Figure 11 is a comparative example (Comparative Example 1) when the shape of the flow projections is modified, and Figure 12 is a comparative example (Comparative Example 2) when the spacing of the flow projections is modified.

In the comparative example of Figure 11, the number (spacing) of flow protrusions was the same as the embodiment of the present invention, but the upper protrusions were removed. In the comparative example of Figure 12, the shape of the flow projections was the same as the embodiment of the present invention, but the number (spacing) of the flow projections was different.

Figure 13 is flow rate experiment comparison data between a conventional back cage and a back cage according to embodiments of the present invention.

Referring to FIG. 13, it can be seen that in the case of a back cage without the existing lower venturi 220, the flow rate drops rapidly at the lower part (1.5 m or less) of the bag filter. In contrast, in Examples 1 and 2 of the present invention, it can be seen that the flow rate slowly decreases even at points below 1.5 m.

It is believed that this is because the through-hole diameter of the lower venturi 220 is smaller than the through-hole diameter of the upper venturi 210, and the speed of the pulse jet increases as it passes through the lower venturi 220.

In Example 1, as shown in FIGS. 4 to 7, there are no flow protrusions inside the lower venturi 220. Therefore, the lower venturi 220 only serves to increase the flow speed by reducing the cross-sectional area through which air passes, and it can be seen that the speed is smoothly reduced as shown.

In Example 2, flow protrusions exist on the inner surface of the cylindrical member of the lower venturi 220. The shape and arrangement of the flow protrusions applied to this embodiment are shown in Figures 9 and 10. The flow protuberances form a certain amount of tangential airflow in the descending airflow. However, if the tangential airflow is too strong, it becomes difficult to transmit the impact to the bag filter, so in this embodiment, a left curved surface 231h is added to the upper protrusion to weaken the tangential airflow generated by the lower protrusion 231b. As a result of applying this structure, it can be seen that the flow rate can be increased by about 10% up to the 1.3 m point, as shown in FIG. 13.

Referring to FIG. 14, it can be seen through the vector of venturi how the pulse jet flow changes in each of the embodiments and comparative examples of the present invention.

In FIG. 14, the first graph is the pulse jet flow when the lower venturi 220 does not exist, the second graph is the pulse jet flow when Example 2 of the present invention is applied, and the third graph is the comparative example of FIG. 11 (Comparative Example 1) ), the fourth is a pulse jet flow when applying the comparative example (Comparative Example 2) of FIG. 12, the fifth is a flow protrusion without the upper and lower protrusions 231b and only the vertical protrusion (231a). This is the pulse jet flow when present (Comparative Example 3).

When the lower venturi 220 does not exist, the hydraulic pressure appears strong near the upper venturi 210, and the hydraulic pressure becomes weaker as it goes downward. It can be seen that the amount of impact applied to the bag filter weakens sharply as you go lower than the middle.

In the embodiment of the present invention, the through-hole diameter of the lower venturi 220 is smaller than the through-hole diameter of the upper venturi 210, so the pressure applied to the upper part of the bag filter by the air accumulating near the lower venturi 220 is You can see that it increases significantly. In addition, as the flow rate increases while passing through the lower venturi 220, it can be seen that the hydraulic pressure is maintained strong even after passing through the middle part of the bag filter.

In Comparative Example 1, it can be confirmed that the hydraulic pressure becomes stronger below the middle part of the bag filter compared to the existing case, but it can be confirmed that the efficiency is lower than in the Example.

In Comparative Example 2, as the spacing between the flow protrusions becomes smaller, the hydraulic pressure between the upper venturi 210 and the lower venturi 220 becomes stronger compared to the example, but it can be seen that the hydraulic pressure below the lower venturi 220 decreases.

Comparative Example 3 is a case where only the vertical protrusion (231a) exists in the flow protrusion and the upper protrusion and lower protrusion (231b) do not exist. In this case, the hydraulic pressure is maintained further downward compared to Comparative Example 1 or Comparative Example 2, but the hydraulic pressure in the left and right directions is weakened, so the amount of impact applied to the bag filter is reduced.

As a result of checking the above pulse jet flow graph, it can be seen that the structure of Example 2 of the present invention is a structure that can demonstrate optimal efficiency compared to other comparative examples in which the shape or spacing of the protrusions is changed.

Referring to FIG. 14, it can be seen that the performance of the embodiment of the present invention and the comparative examples are significantly different at a distance of 1.5 m or less.

Therefore, in FIGS. 15A to 15C, specific speed data at points below 1.5 m are checked.

Figure 15a is flow rate experimental comparison data between the back cage according to an embodiment of the present invention and the back cage according to Comparative Example 1, and Figure 15b is the flow rate experimental data of the back cage according to an embodiment of the present invention and the back cage according to Comparative Example 2. This is flow rate experiment comparison data, and Figure 15c is flow rate experiment comparison data between the back cage according to an embodiment of the present invention and the back cage according to Comparative Example 3.

Referring to FIG. 15A, it can be seen that when the upper protrusion is not present on the flow protrusion, the flow velocity does not concentrate and the flow velocity at the bottom of the bag filter becomes weaker compared to the embodiment.

Referring to FIG. 15b, it can be seen that even if the flow protrusions have upper protrusions, if the spacing between the flow protrusions becomes too narrow, the flow rate decreases further at the bottom of the bag filter than in Comparative Example 1.

Referring to FIG. 15C, when neither the upper nor lower protrusion (231b) exists in the follow protrusion, the downward airflow becomes stronger, so the rate of decrease in flow rate is lower (the slope is larger) than in Comparative Examples 1 and 2, but at 1.1 to 1.5 m. It can be seen that the flow rate in the section is lowered by about 20% compared to the example. This is believed to be because when only the vertical protrusion (231a) is present, the descending airflow becomes stronger, but the tangential airflow formed by the upper and lower protrusions (231b) is not generated.

According to at least one embodiment of the present invention described above, the integrated back cage unit causes surrounding air to flow into the primary venturi due to the pressure difference between the compressed air and the compressed air discharged from the blow tube, causing primary dusting, By controlling the flow rate and pressure of the existing flow through the secondary venturi, the flow rate and pressure are reduced by 20 to 30% compared to the conventional back cage. Compared to the prior art, it is possible to improve the desorption efficiency in long bag filters by increasing the flow rate and pressure at the bottom of the bag filter during the desorption process, and it is possible to lower the facility and operating costs of the filter dust collector. Improved effects can be expected.

The embodiments described in this specification and the accompanying drawings merely illustratively illustrate some of the technical ideas included in the present invention. Accordingly, the embodiments disclosed in this specification are not intended to limit the technical idea of the present invention, and therefore, it is obvious that the scope of the technical idea of the present invention is not limited by these examples. All modifications and specific embodiments that can be easily inferred by a person skilled in the art within the scope of the technical idea included in the specification and drawings of the present invention should be construed as being included in the scope of the present invention.

100: Filter dust collector
102: hood
110: housing
120: bag filter
120a: one hundred
120b: cage
132: injection pipe
134: header
136: connector
138: ball valve
140: pulse valve
142: connector
150: injector
160: fastening member
170: Dust Hopper
180: rotary valve
190: outlet
200: Venturi unit
210: upper venturi
211: Plane member
212: first oblique surface member
213: Cylindrical member
214: second inclined plane member
220: lower venturi
221: Plane member
222: First oblique surface member
223: Cylindrical member
224: Second inclined plane member
230: flow control unit
231: first flow protrusion
231a: Vertical projection
231b: lower protrusion
231c: depression surface
231d: protruding surface
231e: Inflection line
231f: Upper protrusion
231g: Right curved surface
231h: Left curved surface
232: Second flow protrusion
232a: Vertical projection
232b: lower protrusion
232c: depression surface
232d: protruding surface
232e: Inflection line
232f: Upper protrusion
232g: Right curved surface
232h: Left curved surface

Claims (10)

Back cage forming the frame of the bag filter;
an upper venturi disposed at the top of the back cage to introduce pulse jets generated from the injector; and
An integrated back cage unit including a lower venturi that is spaced downward from the upper venturi and is formed to increase the flow rate by guiding the pulse jet that has passed through the upper venturi into a narrow through hole. According to paragraph 1,
The lower venturi,
A flat member extending in the width direction;
a first inclined surface member extending from an inner end of the flat member to form an inclined surface inclined inward;
a cylindrical member extending downward from an end of the inclined surface member; and
An integrated back cage unit comprising a second inclined surface member extending from an end of the cylindrical member to form an inclined surface inclined outward. According to paragraph 2,
The lower venturi,
An integrated back cage unit located at 1/3 of the back cage. According to paragraph 2,
An integrated back cage unit, characterized in that the diameter of the center hole of the flat member is less than 2/3 of the diameter of the center hole of the upper venturi. According to paragraph 2,
An integrated back cage unit, characterized in that it further includes a flow control unit formed on the inner surface of the cylindrical member to control pulse jet flow. According to clause 5,
The flow control unit is,
An integrated back cage unit comprising eight flow protrusions arranged at equal intervals. According to clause 6,
The flow protrusions are,
Vertical protrusions extending in a vertical direction;
a lower protrusion protruding in one direction from the lower end of the vertical protrusion; and
An integrated back cage unit comprising an upper protrusion protruding from the upper end of the vertical protrusion in the other direction. In clause 7,
An integrated back cage unit, characterized in that the area (B) of the space between adjacent flow projections is 40% to 60% of the area (A) of the flow projections when viewed from the top. In clause 7,
The upper surface of the lower protrusion includes a recessed surface and a protruding surface,
An integrated back cage unit, characterized in that an inflection line whose curvature changes from positive to negative is formed between the recessed surface and the protruding surface. According to clause 9,
The upper surface of the lower protrusion includes a recessed surface and a protruding surface, and an inflection line whose curvature changes from positive to negative is formed between the recessed surface and the protruding surface,
An integrated back cage unit, characterized in that the upper surface of the upper protrusion includes a left curved surface and a right curved surface curved downward.

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