JP2011050824A - Pulse type dust collector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulse type dust collector capable of extremly accelerating pressure rising speed in an injector tube accompanying the opening operation of an on-off valve without causing problems that the device is made large in size and the air consumption is increased, and improving dust shaking off performance by means of the propagation of a pressure wave to inside of a filter part. <P>SOLUTION: In a compressed air jetting part of the pulse type dust collector, a plurality of jetting holes 17 connecting a compressed air source for independently jetting the compressed air H to a plurality of filters from the compressed air source are provided in the longitudinal direction and an induction part 30 capable of inducing outside air OA into an injector tube by the air stream of the compressed air H supplied to the inside of the injector tube 15 from the base end side to the tip side through the on-off valve is provided in a base end side area P between the base end where the on-off valve is provided and a place where the jetting holes 17a most closed to the base end in the plurality of the jetting holes 17 is provided in the injector tube 15 connected to the compressed air source through the on-off valve at the base end. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention includes a housing whose interior is partitioned into a dust-containing air introduction chamber and a purified air chamber by a partition wall, and each of a plurality of communication portions that communicate the dust-containing air introduction chamber and the purified air chamber among the partition walls. A filter unit having a plurality of filters for collecting dust contained in the dust-containing air flowing from the dust-containing air introduction chamber side to the purified air chamber side, and from the purified air chamber side through the filter unit The present invention relates to a pulse type dust collector including a compressed air ejection unit that ejects compressed air to a dust-containing air introduction chamber side and cleans dust adhering to a filter unit.

  The pulse type dust collector collects dust contained in the dust-containing air flowing from the dust-containing air introduction chamber side to the purified air chamber side in the housing by the filter unit, and incinerators, crushing facilities, etc. This is a device that purifies the dust-containing air supplied from the filter. Further, the dust collected and adhered to the filter unit is compressed from the purified air chamber side to the dust-containing air introduction chamber side through the filter unit by the compressed air ejection unit. It is configured such that air can be ejected, cleaned, and cleaned (see, for example, Patent Document 1).

In the pulse dust collector described in Patent Document 1, the compressed air ejection part includes an injector tube (tube member) having a proximal end connected to a compressed air source and a closed end, and compressed air from the compressed air source. Is provided with a plurality of on-off valves that can be intermittently supplied into the injector tube, and a plurality of ejection holes that are provided in the longitudinal direction of the injector tube and that individually eject the compressed air supplied into the injector tube into the plurality of filters. .
As a result, even if dust is collected and adhered to the filter part and the pressure loss in the filter part increases, the opening / closing valve is opened while the dust is still collected on the filter part. Then, the pressure air (pulse wave) is propagated from the purified air chamber side to the dust-containing air introduction chamber side through the filter by ejecting compressed air from the plurality of ejection holes into the inside of the plurality of filters through the injector tube. The dust adhering to the outer surface of the filter (on the dust-containing air introduction chamber side) can be removed.

  Here, for example, in the pulse type dust collector described in Patent Document 1, a plurality of bag filters having a filter portion suspended from the communication portion of the partition wall, that is, a bag shape covered with a cage-shaped support body Filter (filter cloth). When cleaning the bag filter, the compressed air is ejected from the ejection hole, so that the pressure wave propagating in the direction of ejection propagates from the opening end to the tip in the bag filter, and the filter cloth itself instantaneously In general, the dust that has been expanded in the outer diameter direction and adhered to the outer surface of the filter cloth is wiped off and cleaned in the outer diameter direction, thereby eliminating clogging. The removed dust falls to the bottom of the housing and is collected.

Japanese Utility Model Publication No. 6-15713

  In the pulse dust collector, the injector tube is configured such that the proximal end is connected to the compressed air source via the on-off valve and the distal end is closed. The pressure is increased only by the supply of compressed air through the on-off valve, and the compressed air is ejected from the ejection holes by the pressure increase. Therefore, in order to improve the effect of removing dust adhering to the filter part, the pressure (static pressure) in the injector tube is increased in as short a time as possible, and compressed air is ejected from the ejection hole into the filter part at once. Thus, it is important to form a pressure wave in a high energy state.

However, in the pulse dust collector described in Patent Document 1, since the pressure increase in the injector tube is only due to the supply of compressed air through the on-off valve, the injector tube is limited due to pressure loss and the like in the on-off valve. There is a limit to improving the rate of pressure increase inside.
Moreover, since the several injection hole is provided in the longitudinal direction of the injector tube, the length of an injector tube inevitably becomes long and it exists in the tendency for the pressure rise speed in an injector tube to fall.
Furthermore, it is conceivable to increase the size of the on-off valve or the like in order to improve the pressure increase rate in the injector tube, but problems such as an increase in the size of the device, an increase in the amount of air consumption, and an increase in cost arise.

  The present invention has been made in view of the above circumstances, and its purpose is not to cause problems such as an increase in the size of the apparatus and an increase in the amount of air consumed, and the purpose of the present invention As the pressure rise speed is extremely rapid, the pressure wave in the extremely high energy state is formed by the jet of compressed air from the jet hole, and the dust removal performance by the propagation of the pressure wave into the filter part can be improved. The object is to provide a pulse-type dust collector capable.

In order to achieve the above object, a pulse dust collector according to the present invention includes a housing whose interior is partitioned by a partition wall into a dust-containing air introduction chamber and a purified air chamber, and the dust-containing air among the partition walls. Dust contained in the dust-containing air that is provided in each of a plurality of communicating portions that communicate between the introduction chamber and the purified air chamber and that flows from the dust-containing air introduction chamber side to the purified air chamber side is collected. A filter unit having a plurality of filters, and a compressed air ejection unit that ejects compressed air from the purified air chamber side to the dust-containing air introduction chamber side through the filter unit to clean dust adhering to the filter unit And
An injector tube having a proximal end connected to a compressed air source and closed at a distal end; and an on-off valve capable of intermittently supplying the compressed air from the compressed air source into the injector tube. A pulse-type dust collecting device provided with a plurality of nozzles provided in the longitudinal direction of the injector tube, and each having a plurality of jets for injecting the compressed air supplied into the injector tube into the plurality of filters. The configuration is
In the injector tube of the compressed air ejection part, in a proximal side region between a proximal end where the on-off valve is provided and a location where an ejection hole closest to the proximal end is provided among the plurality of ejection holes. And an attracting portion capable of attracting external air into the injector tube by an air flow of the compressed air supplied from the proximal end side toward the distal end side into the injector tube through the on-off valve. In the point.

According to this characteristic configuration, the proximal end region of the injector tube is provided with an attracting portion capable of attracting external air into the injector tube, so that the compressed air source is compressed via the on-off valve by opening the on-off valve. When the air flow of air is supplied into the injector tube at a high speed, a negative pressure is generated around the air flow due to the venturi effect caused by the flow of the high-speed air flow through the proximal end region. External air is forcibly attracted into the injector tube via an attracting portion provided in the proximal end region. Note that the flow velocity of the high-speed air flow is, for example, about the speed of sound, that is, about 300 to 350 m / sec.
In other words, not only the compressed air supplied through the opening / closing valve but also the external air forced through the induction part is instantaneously supplied to the tip side of the induction part in the injector tube. The pressure in the injector tube can be increased very quickly.
In addition, even when an on-off valve having the same configuration as the conventional one is used without modifying the on-off valve configuration, the pressure in the injector tube is reduced by forcibly attracting external air from the attraction portion as described above. It can be raised very quickly.
Therefore, without causing problems such as an increase in the size of the device and an increase in the amount of air consumed, the pressure rise rate in the injector tube accompanying the opening operation of the on-off valve can be made extremely quick, and the compressed air from the outlet hole can be filtered. As a result, the pressure wave in an extremely high energy state is formed by jetting into the filter, and it is possible to improve dust removal performance by propagation of the pressure wave into the filter portion.

  A further characteristic configuration of the pulse dust collector according to the present invention is such that the injector tube includes a proximal end side tube member provided on the proximal end side and a distal end side tube member provided on the distal end side. The proximal end side tube member is inserted into the distal end side tube member in a state where the attracting portion forms a radial gap between the proximal end side tube member and the distal end side tube member. It is in the point which is comprised.

  According to this characteristic configuration, the attracting portion provided in the injector tube forms a radial gap between the proximal end side tube member provided on the proximal end side and the distal end side tube member provided on the distal end side. Since the proximal end side pipe member is inserted into the distal end side pipe member, it is possible to form an attracting part that attracts external air using the Venturi effect with a very simple configuration. In addition, since the flow direction of the external air to be attracted is the front end side direction substantially the same as the flow direction of the air flow of the compressed air H, the external air can be favorably attracted by the Venturi effect. The gap in the radial direction between the two pipe members is also affected by the speed of the compressed air flowing through the vicinity of the attracting part, the amount of air, the shape of the attracting part, the diameter of the pipe member, etc. The air flow is formed at a relatively narrow interval so that external air can be attracted into the injector tube by the negative pressure generated by the venturi effect around the air flow.

  A further characteristic configuration of the pulse dust collector according to the present invention is that the proximal end portion of the distal end side pipe member has an enlarged diameter portion whose diameter is increased toward the proximal end side. The proximal end side pipe member is inserted in the proximal end portion.

  According to this characteristic configuration, since the proximal end side tube member is inserted into the proximal end portion of the distal end side tube member whose diameter has been expanded by the expanded diameter portion, in the injector tube, from the expanded diameter portion of the distal end side tube member In addition, the cross-sectional area of the distal end side (the portion where the diameter is not expanded) can be made substantially equal to the cross-sectional area of the distal end portion of the proximal end side pipe member. Therefore, when the compressed air flow passes through the proximal end side pipe member and then flows through the distal end side pipe member, the reduction in the speed of the air flow accompanying the increase in the sectional area of the distal end side pipe member is suppressed. It is possible to prevent a decrease in the pressure increase rate in the injector tube due to the air flow.

  A further characteristic configuration of the pulse dust collector according to the present invention is that a distal end portion of the proximal end side tube member is formed with a tapered portion that is reduced in diameter toward the distal end side of the distal end portion of the proximal end side tube member. There is in point.

  According to this characteristic configuration, the distal end portion of the proximal end side pipe member is provided with a tapered portion that is reduced in diameter toward the distal end side, and this tapered portion functions as a so-called throttle, so that the compressed air in the proximal end side tube member is compressed. The velocity of the air flow can be accelerated with a taper and allowed to flow from the proximal tube member to the distal tube member. This further increases the generation of negative pressure due to the venturi effect in the vicinity of the attracting portion formed between the proximal end side tube member and the distal end side tube member, and attracts external air from the attracting portion into the injector tube. The force can be increased, and as a result, the pressure increase rate in the injector tube can be further increased.

Schematic side sectional view of pulse dust collector Schematic top view of the pulse dust collector Enlarged cross-sectional view showing the configuration near the attracting part Schematic side cross-sectional view of a pulse dust collector showing operation during normal operation Schematic side cross-sectional view of pulse dust collector showing operation during cleaning operation The graph which shows the static pressure distribution in the injector tube at the time of the cleaning operation of the pulse type dust collector which concerns on an Example. The graph which shows the static pressure distribution in the injector tube at the time of the cleaning operation of the pulse type dust collector which concerns on a comparative example The graph which shows the relationship between the elapsed time from opening operation of an air on-off valve, and the pressure in a certain nozzle hole position Enlarged sectional view showing a configuration in the vicinity of the attracting portion according to another embodiment Enlarged sectional view showing a configuration in the vicinity of the attracting portion according to another embodiment Enlarged sectional view showing a configuration in the vicinity of the attracting portion according to another embodiment

Hereinafter, in the pulse dust collector A according to the present invention, an embodiment in which a bag filter 5 is used as a filter unit will be described.
As shown in FIG. 1 and FIG. 2, the pulse dust collector A includes a housing 1 whose interior is partitioned by a partition wall 4 into a dust-containing air introduction chamber 2 and a purified air chamber 3, and the partition wall 4. Included in the dust-containing air G that is provided in each of the plurality of communication portions 6 that communicate the dust-containing air introduction chamber 2 and the purified air chamber 3 and flows from the dust-containing air introduction chamber 2 side to the purified air chamber 3 side. Bag filter 5 (an example of a filter unit) that collects dust D to be collected, and compressed air H is jetted from the purified air chamber 3 side to the dust-containing air introduction chamber 2 side through the bag filter 5, 5 includes a compressed air ejection part 7 for cleaning the dust D adhering to 5 and a control part 8 for controlling the operation of the pulse dust collector A such as the operation of the compressed air ejection part 7. Further, the pulse dust collector A includes a pressure difference detection unit 9 that detects a pressure difference between the inside and the outside of the bag filter 5.

The housing 1 is partitioned by a partition wall 4 in the vertical direction, a dust-containing air introduction chamber 2 through which dust-containing air G flows, and a bag filter 5 provided at a communication portion 6 of the partition wall 4 at the top. A purified air chamber 3 is formed through which the purified air C purified by the air flows. The casing 1 is formed in a rectangular shape in a top view when the bag filter 5 is disposed in the dust-containing air introduction chamber 2 and the portion where the purified air chamber 3 is formed, and the bag filter in the dust-containing air introduction chamber 2 is formed. The lower outer shape of the place where 5 is arranged is formed in a funnel shape.
A dust-containing air introduction path 10 for introducing dust-containing air G from an incinerator or the like (not shown) into the dust-containing air introduction chamber 2 is formed at the upper end portion of the housing 1 formed in the funnel shape. A purified air discharge path 11 for discharging the purified air C purified by the bag filter 5 from the purified air chamber 3 is formed at an upper portion formed in the rectangular shape of the housing 1. A suction device (not shown) is provided on the downstream side of the purified air discharge passage 11 so that the purified air C in the purified air chamber 3 can be sucked into the external space. In addition, a discharge port 12 provided with a rotary valve is formed at the lower end of the portion formed in the funnel shape of the housing 1, and the inside of the dust-containing air introduction chamber 2 generated by cleaning the bag filter 5 described later or the like. The dust D and the like can be discharged.
Therefore, the dust-containing air G generated in an incinerator or the like (not shown) is introduced into the dust-containing air introduction chamber 2 through the dust-containing air introduction path 10 by the suction force of the suction device (not shown). Dust D is collected by the bag filter 5 to become purified air C, which is discharged from the purified air chamber 3 to the external space connected to the downstream side of the dust collector A via the purified air discharge passage 11. .

As shown in FIGS. 1, 4 and 5, the bag filter 5 has a bottomed cage shape (for example, a plurality of straight rod-shaped bodies attached to a plurality of ring-shaped frame bodies formed in an annular shape. A bag-like bug 5b (an example of a filter) configured to allow the dust-containing air G to flow is covered on the outside of the support 5a formed in a shape of a cage).
The bug 5b is composed of a filter cloth that can satisfactorily collect the dust D in the dust-containing air G. For example, a base cloth formed by a non-woven cloth attached on the outside of the cloth or a non-woven cloth or a woven cloth. Composed of cloth or the like. The material of the filter cloth is made of synthetic fiber or glass fiber. The lower part of the bug 5b is formed in a bag shape, and the upper part is provided with an opening. A guide pipe 13 of a compressed air ejection part 7 to be described later is attached to the opening, and the upper end part of the bug 5b is formed by the guide pipe 13 and the support 5a. It is clamped and fixed to the communication part 6 of the partition wall 4.
The bag filter 5 is attached to the communication portion 6 of the partition wall 4 in a suspended state. In the present embodiment, 20 bag filters 5 are provided in a state where 4 pieces are arranged vertically (up and down in FIG. 2) and 5 pieces are arranged horizontally (in the left and right direction in FIG. 2). The arrangement location, the number of arrangements, the shape of the support 5a, the shape of the bug 5b, the presence / absence of the guide tube 13, and the like can be appropriately changed in relation to the amount of dust D processed.

The compressed air ejection section 7 is configured to be able to eject the compressed air H intermittently (in a pulse shape) to the inside of each bag filter 5.
The compressed air ejection part 7 includes an injector tube 15 having a proximal end 15A connected to a header part 14 (an example of a compressed air source) and a closed end 15B, and compressed air H from the header part 14 into the injector tube 15. A plurality of air on-off valves 16 (an example of on-off valves) that can be intermittently supplied and a plurality of compressed air H provided in the longitudinal direction of the injector tube 15 and supplied to the inside of the plurality of bag filters 5. A plurality of ejection holes 17 are separately ejected.
Further, the compressed air ejection section 7 adjusts the pressure of compressed air H from a compressor or the like via a pressure regulating valve 19 provided in the compressed air supply path 18, and then in each header section 14 (in FIG. 14a, 14b, 14c, and 14d). Then, the compressed air ejection section 7 converts the compressed air H stored in each header section 14 into air on / off valves 16 (not shown, but 16a, 16b, 16c, 16d) provided in the header sections 14, respectively. 4), and is distributed to each of the plurality of injector tubes 15 (four in FIG. 2, four of 15a, 15b, 15c, 15d), and the plurality of jets provided in the injector tube 15 is distributed. It is configured to be able to eject from the hole 17 to the inside of each bag filter 5 through each guide tube 13. In the example shown in FIG. 1, five ejection holes 17 (for example, 17a, 17b, 17c, 17d, and 17e) are provided for one injector tube 15 (for example, 15d).

The opening / closing of each air on / off valve 16 is configured to be controllable by operating sections 20 (four in FIG. 2, 20 a, 20 b, 20 c, and 20 d) provided corresponding to each air on / off valve 16. Each ejection hole 17 is arranged on the upper part of each bag filter 5 so as to correspond to each bug filter 5 on a one-to-one basis. In addition, five bag filters 5 are arranged in parallel in the first injector tube 15a corresponding to the first air on-off valve 16a, and similarly, the second injector tube 15b corresponding to the second air on-off valve 16b, the third air Five bag filters 5 are arranged in parallel in the third injector tube 15c corresponding to the on-off valve 16c and the fourth injector tube 15d corresponding to the fourth air on-off valve 16d, respectively. Therefore, the compressed air H stored in the header portion 14 is in an open / closed state in which the operation portions 20 are controlled by the control portion 8 and the opening / closing of the air on / off valves 16 corresponding to the operation portions 20 is set. By being controlled so as to be, it is possible to eject intermittently (in a pulse form) inside each bag filter 5 through each ejection hole 17. The pressure and the air amount of the compressed air H stored in each header portion 14 can be appropriately set according to the pressure and the air amount of the compressed air H that needs to be ejected. For example, the pressure is 2 MPa, The capacity can be set to about 450 cm ^3, and the air flow of the compressed air H when the air on-off valve 16 is opened is, for example, about the speed of sound, that is, about 300 to 350 m / sec.

  The control unit 8 includes a central processing unit (CPU), a memory, a storage unit, and the like (not shown), and includes known information processing means that can execute a predetermined program and process information by the CPU. The operation of the pulse dust collector A can be controlled.

As shown in FIG. 1, the pressure difference detection unit 9 is provided in a dust-containing air introduction path 10 and detects the pressure outside the bag filter 5 (on the dust-containing air introduction chamber 2 side). A first pressure detection unit 9a; and a second pressure detection unit 9b that is provided in the purified air discharge passage 11 and detects the pressure inside the bag filter 5 (purified air chamber 3 side). These first pressure detection units Based on the detected pressure from 9a and the 2nd pressure detection part 9b, it is comprised so that the internal / external differential pressure | voltage of the bag filter 5 can be detected. The detected internal / external differential pressure of the bag filter 5 is configured to be output to the control unit 8.
The pressure difference detection unit 9 includes a third pressure detection unit 9c that detects the pressure inside the bag filter 5 (inside the bag 5b of the bag filter 5), and includes a first pressure detection unit 9a and a third pressure detection unit. The difference in detected pressure from 9c can be measured as the internal / external pressure difference of the bag filter 5. Further, a predetermined pressure difference serving as a reference for determining that the dust D has adhered to the outside of the bag filter 5 and the dust D cannot be efficiently collected is set in advance. That is, the pressure difference between the inside and outside of the bag filter 5 is a pressure loss of the dust-containing air G flowing from the outside to the inside of the bag filter 5, whereas the predetermined pressure difference requires the bag filter 5 to be cleaned. It is set as the value of the pressure loss in the case of a new state. The predetermined pressure difference is output to the control unit 8 and can be stored in the storage unit of the control unit 8 in advance.
The purified air discharge path 11 is provided with a known flow rate detection unit 21 that detects the flow rate of the purified air C discharged from the purified air chamber 3 to the external space, and the detected flow rate is output to the control unit 8. Is configured to do.

Next, the further structure of the compressed air ejection part 7 which is the characteristic structure of this application is demonstrated.
As shown in FIGS. 1 to 5, the compressed air ejection portion 7 in the present embodiment includes an injector tube 15 having a proximal end 15 </ b> A connected to a header portion 14 (an example of a compressed air source) and a distal end 15 </ b> B closed. Prepare.
The injector tube 15 includes a cylindrical proximal end side tube member 31 provided on the proximal end 15A side and a cylindrical distal end side tube member 32 provided on the distal end 15B side.
As shown in FIG. 3, the injector tube 15 has the proximal tube member 31 at the distal end with a radial gap S formed between the proximal tube member 31 and the distal tube member 32. The attracting portion 30 is configured by being inserted into the side tube member 32 up to a predetermined site. In FIG. 3, the proximal end side pipe member 31 and the distal end side pipe member 32 are inserted in a concentric state in which the respective axial centers are made common.
That is, in this injector tube 15, the base end side region P between the base end 15 </ b> A where the air opening / closing valve 16 is provided and the location where the ejection hole 17 a closest to the base end 15 </ b> A is provided among the plurality of ejection holes 17. Further, an attracting portion capable of attracting the external air OA into the injector tube 15 by the air flow of the compressed air H supplied from the base end 15A side toward the distal end 15B side into the injector tube 15 via the air opening / closing valve 16 30 is formed.

  As shown in FIG. 3, the proximal end side pipe member 31 is connected to the distal end portion 31a of the proximal end side tube member 31 with the inner diameter X of the proximal end cylindrical portion 31d of the proximal end side tube member 31 (even the maximum inner diameter of the distal end portion 31a). A tapered portion 31b that is reduced in diameter toward the distal end 15B side is formed, and this tapered portion 31b is in response to the air flow of the compressed air H that flows from the proximal end side to the distal end side in the proximal end side pipe member 31. It functions as a so-called diaphragm. Further, a distal end cylindrical portion 31c having an inner diameter substantially the same as the minimum inner diameter (not shown) of the tapered portion 31b is formed on the distal end 15B side of the tapered portion 31b in the distal end portion 31a.

As shown in FIG. 3, the distal end side tube member 32 is formed with a diameter-expanded portion 32 b that increases in diameter toward the proximal end 15 </ b> A side at the proximal end portion 32 a of the distal end side tube member 32. Further, a proximal end cylindrical portion 32d having an inner diameter Z substantially the same as the maximum inner diameter Z of the enlarged diameter portion 32b is provided on the proximal end 15A side of the enlarged diameter portion 32b in the proximal end portion 32a. Further, the distal end side pipe member 32 includes a distal end cylindrical portion 32c having an inner diameter Y substantially the same as the minimum inner diameter Y of the expanded diameter portion 32b on the distal end 15B side of the expanded diameter portion 32b.
That is, in a state where the proximal end side pipe member 31 is inserted into the proximal end portion 32a of the distal end side tube member 32, the inner diameter of the distal end side tube member 32 is increased toward the proximal end 15A side, and the proximal end side It has an enlarged diameter portion 32b that is set to be equal to or larger than the inner diameter of the distal end portion 31a of the tube member 31 and less than the inner diameter Z of the proximal end cylindrical portion 32d of the distal end side tube member 32. FIG. 3 shows an example in which the minimum inner diameter Y of the enlarged diameter portion 32 b of the distal end side tube member 32 is substantially the same as the maximum inner diameter X of the distal end portion 31 a of the proximal end side tube member 31.

Therefore, the attracting part 30 of the injector tube 15 inserts the proximal end side pipe member 31 into the proximal end part 32 a of the distal end side pipe member 32, thereby providing a predetermined radial direction between these pipe members 31 and 32. The gaps S are formed at intervals. Thereby, the attraction | suction part 30 is connecting the exterior of the injector tube 15 and the inside of the injector tube 15 through the clearance gap S, and the compressed air which flows through the base end side pipe member 31 and the front end side pipe member 32 The external air OA can be attracted into the injector tube 15 by the negative pressure generated by the venturi effect around the H air flow.
The gap S having a predetermined interval in the radial direction between the pipe members 31 and 32 is the speed of the compressed air H flowing through the vicinity of the attracting part 30, the amount of air, the shape of the attracting part 30, the pipe member Although it is influenced by the diameters 31 and 32, the external air OA is formed at a relatively narrow interval around the air flow so that the external air OA can be attracted into the injector tube 15 by the negative pressure generated by the venturi effect. . Further, in FIG. 3, the gap S having a predetermined interval in the radial direction between the pipe members 31 and 32 is formed so as to be substantially the same interval at a portion where the proximal end side pipe member 31 is inserted. Yes.

  The distal end tubular portion 31c on the distal end side of the tapered portion 31b of the proximal end side tube member 31 is reversely arranged so as to close the gap S across the distal end tubular portion 31c and the distal end tubular portion 32c of the distal end side tube member 32. A restricting member 33 as a stop valve is provided. The restricting member 33 allows the external air OA to be attracted into the injector tube 15 from the external space through the clearance S of the attracting portion 30 due to the negative pressure due to the venturi effect of the air flow of the compressed air H. It is configured to be able to regulate the flow of compressed air H from the injector tube 15 to the external space via S. The regulating member 33 is, for example, a tongue-shaped member in a cross-sectional view, and is open when a negative pressure is generated by the air flow of the compressed air H, and is a check valve that is closed when no negative pressure is generated. It can comprise with the flexible member which can exhibit the function as.

Next, the normal operation and the cleaning operation will be described for the operation state of the pulse dust collector A controlled by the control of the control unit 8.
In the normal operation of the pulse dust collector A, as shown in FIG. 4, the control unit 8 starts suction by a suction device (not shown) connected to the downstream side of the purified air discharge path 11 to contain dust. Dust-containing air G is introduced into the dust-containing air introduction chamber 2 in the housing 1 from an incinerator or the like (not shown) connected to the upstream side of the air introduction path 10. As a result, the dust-containing air G is caused to flow from the dust-containing air introduction chamber 2 side to the purified air chamber 3 side through the bag filter 5 (from the outside to the inside of the bag filter 5). D is collected by the bug 5b of the bag filter 5 to purify the dust-containing air G and process it as purified air C. Here, the bag filter 5 before the start of the normal operation is in a state in which the bug 5b is simply covered on the outside of the support 5a. However, when the normal operation is started, as shown in FIG. Is attracted to the inside of the support 5a, and the bug 5b comes into close contact with the outside of the support 5a. In this normal operation, the collected dust D adheres to the outer surface of the bag 5b of the bag filter 5. In addition, the control part 8 monitors the information of the internal / external differential pressure inside and outside the bag filter 5 from the pressure difference detection part 9 (the 1st pressure detection part 9a and the 2nd pressure detection part 9b) in normal driving | operation. . Further, the control unit 8 detects the flow rate of the purified air C discharged from the purified air discharge passage 11 in the normal operation by the flow rate detection unit 21, and the suction device so that the detected flow rate becomes a predetermined flow rate. Etc. (not shown) are controlled.
Thereby, the dust D in the dust-containing air G can be collected by the bag filter 5 and the dust-containing air G can be purified well to obtain purified air C.

On the other hand, if this normal operation is continued, the dust D adhering to the outer surface of the bag filter 5 increases, the dust D adheres in layers to the outside of the bug 5b, and further, the dust D is outside the bug 5b. It adheres not only on the surface but also into the fibrous portion of the filter cloth forming the bug 5b. In such a state, pressure loss occurs in the bag filter 5 and it is difficult to efficiently collect the dust D. Therefore, the control unit 8 detects that the dust D layer has been formed by detecting whether the pressure difference detecting unit 9 (the first pressure detecting unit 9a and the second pressure detecting unit 9b) detects the inside or outside of the bag filter 5. Recognizing that the differential pressure has reached the predetermined pressure differential (predetermined internal / external differential pressure), it is determined that the bag filter 5 needs to be cleaned. The predetermined pressure difference is set in advance as a pressure difference when, for example, a layer of dust D is formed on the bag filter 5 and dust D cannot be efficiently collected, Those stored in the storage unit 8 can be used.
In such a state, in the present application, the cleaning operation of the bag filter 5 is performed in a state where the normal operation is performed (a state where dust D is collected).

  As described above, as shown in FIG. 5, the control unit 8 keeps the suction of the suction device (not shown) and performs the normal operation, and the internal / external differential pressure of the bag filter 5 becomes a predetermined pressure difference. When it becomes, the compressed air ejection part 7 is operated and the bag filter 5 is cleaned. As the cleaning operation, first, the control unit 8 adjusts the opening degree of the pressure regulating valve 19 to store the compressed air H from the compressor (not shown) in the header unit 14, and the compressed air in the header unit 14. Control is performed so that the pressure of H is about 2 MPa.

And the control part 8 controls opening and closing of the specific air on-off valve 16 (for example, air on-off valve corresponding to the header part 14d), and flows outside from each bag filter 5 via the bug 5b. Thus, the compressed air H is ejected intermittently (in a pulse form). The time for which the compressed air H continues to be ejected is, for example, about 0.1 to 0.5 seconds.
Specifically, as shown in FIG. 5, the control unit 8 opens a specific air on-off valve 16 to cause the compressed air H to flow into the injector tube 15 from the proximal end 15 </ b> A side to the distal end 15 </ b> B side. It spouts at a high speed at a stretch toward the.
The air flow of the compressed air H flows through the proximal end side pipe member 31 and further flows through the distal end side pipe member 32, and the pressure in the injector tube 15 is sufficiently increased, so that the distal end side pipe It is ejected from a plurality of ejection holes 17 provided in the member 32, and flows from the inside of the bag filter 5 to the outside through the bag 5b.

Here, the flow of the compressed air H will be described. The compressed air H blown into the injector tube 15 from the header portion 14 through the air on-off valve 16 passes through the proximal end side pipe member 31. Since the tip 31b of the distal end portion 31a having an inner diameter smaller than the inner diameter X of the base end cylindrical portion 31d is passed through, the flow velocity is accelerated by the tip 31b. The accelerated air flow flows through the distal end cylindrical portion 31c having the same inner diameter as the inner diameter (not shown) of the distal end portion of the tapered portion 31b, and flows into the distal end side tube member 32 while maintaining the speed.
At this time, since the air flow of the compressed air H flowing into the distal end side pipe member 32 is very high speed, a negative pressure is generated around the air flow due to the venturi effect, and the vicinity of the attracting portion 30 is large. The pressure is lower than atmospheric pressure. Thereby, the external air OA (for example, about atmospheric pressure) is forcibly applied to the attracting portion 30 in the injector tube 15 through the gap S formed between the proximal end side tube member 31 and the distal end side tube member 32. Will be attracted. When the external air OA is attracted, the regulating member 33 is opened by the negative pressure, and the gap S is formed with a relatively narrow predetermined interval and the same interval in the radial direction. Therefore, the attraction of the external air OA that flows in substantially the same direction as the air flow of the compressed air H is performed better.
Therefore, not only the compressed air H supplied via the air opening / closing valve 16 but also the external air OA forcedly attracted via the attracting part 30 is located on the tip 15B side of the attracting part 30 of the injector tube 15. It is supplied instantaneously, and the pressure in the injector tube 15 can be increased very quickly.

  The fact that the pressure in the injector tube 15 can be increased extremely quickly will be described with reference to FIGS. FIG. 6 is a graph showing the static pressure distribution in the injector tube 15 during the cleaning operation of the pulse dust collector A according to the example of the present embodiment, and FIG. 7 shows the pulse dust collector according to the comparative example. Fig. 8 is a graph showing the static pressure distribution in the injector tube during the cleaning operation, and Fig. 8 is a graph showing the relationship between the elapsed time from the opening operation of the air on-off valve and the pressure (static pressure) at a certain ejection hole position. It is. The static pressure is a pressure on a plane parallel to the velocity of the air flow of the compressed air H flowing through the injector tube 15.

  As shown in FIG. 6, in the example of the present embodiment, the static pressure distribution near the wall surface in the injector tube 15 immediately after the opening operation of the air on-off valve 16 is based on a negative pressure (negative pressure) state. The static pressure rises from the end 15A side toward the tip 15B side, but rises all at once in the vicinity of the attracting portion 30 and is pushed up to near 0 (atmospheric pressure). This is because the negative pressure due to the air flow of the high-speed compressed air H in the proximal end side pipe member 31 is caused by the external air OA attracted to the attracting part 30 through the clearance S opened to the atmosphere, This is because the vicinity of the attracting unit 30 is instantaneously boosted to near 0 (atmospheric pressure). In addition to the compressed air H, the external air OA is attracted, so that an air amount necessary for raising the static pressure in the injector tube 15 over the whole (in particular, the distal end side pipe member 32) is supplied. Therefore, the static pressure is already relatively high even in the region where the plurality of ejection holes 17 are arranged and in the vicinity of the tip portion 15B.

  On the other hand, as shown in FIG. 7, in the pulse type dust collector of the comparative example that does not include the attracting unit 30, when the cleaning operation is performed in the same manner as in the example, immediately after the opening operation of the air on-off valve is performed. In the static pressure distribution near the wall surface in the injector tube, the static pressure increases from the base end side in the negative pressure (negative pressure) state to the tip end. There is no increase and the point where the static pressure is near 0 (atmospheric pressure) is shifted to the tip side. That is, in the embodiment, the vicinity of the attracting portion 30 is near 0, whereas in the comparative example, the static pressure is near 0 on the tip side of the portion corresponding to the attracting portion 30. In addition, since only the compressed air H is supplied into the injector tube, a sufficient amount of air is not supplied to increase the static pressure in the injector tube as a whole. The static pressure is relatively low in the region where the holes are arranged and in the vicinity of the tip portion 15B.

  Furthermore, as shown in FIG. 8, the static pressure at the position where a certain ejection hole 17 is provided is very short with a steep slope of the graph as time elapses from the opening operation of the air on-off valve 16. The pressure increased at a stroke over time (see the one-dot chain line in FIG. 8), and in the comparative example, it was found that the slope of the graph was relatively gentle and a relatively long time was required until the pressure increased.

  Therefore, by adopting the injector tube 15 having the above-described characteristic configuration as in the pulse dust collector A according to the present embodiment, the pressure in the injector tube 15 can be increased extremely quickly. Further, even when the air on / off valve 16 having the same configuration as the conventional one is used without modifying the configuration of the air on / off valve 16, the pressure in the injector tube 15 can be increased very quickly.

Then, the compressed air H supplied by the opening operation of the air on-off valve 16 and the external air OA attracted by the attracting unit 30 increase the pressure in the injector tube 15 very rapidly, and the tip of the injector tube 15. It reaches the 15B side and starts flowing again to the base end side 15A. At this stage, since the pressure in the injector tube 15 is sufficiently increased, the air flow of the compressed air H toward the proximal end 15A side sequentially causes the plurality of ejection holes 17 provided in the distal end side pipe member 32 to sequentially flow. It will be ejected inside each bag filter 5. Specifically, the compressed air H is mainly ejected in the order of the ejection holes 17e, 17d, 17c, 17b, and 17a shown in FIG.
In this manner, the pressure wave in the extremely high energy state can be propagated into the bag filter 5 by ejecting the compressed air H into the bag filter 5 from the ejection hole 17 in a state where the pressure is increased very quickly. . As a result, the bug 5b is reversed from the state contracted inward (the state shown in FIG. 4), and the bag 5b is surely expanded outward and is in a tension state (see FIG. 5). The opening of the portion becomes large, and the dust D adhering in a layered manner to the outer surface of the bug 5b can be removed to clean well.

  Therefore, without causing problems such as an increase in the size of the apparatus and an increase in the amount of consumed air, the pressure rise speed in the injector tube 15 accompanying the opening operation of the on-off valve can be made extremely quick, and the compressed air H from the ejection hole 17 can be obtained. The pressure wave in an extremely high energy state is formed by jetting into the filter part, and it is possible to improve the dust removal performance by propagation of the pressure wave into the filter part.

[Another embodiment]
(1) In the above-described embodiment, the proximal end side tube member 31 is moved in a state where the radial gap S is formed between the proximal end side tube member 31 and the distal end side tube member 32. The proximal end tube member 31 is configured to be inserted into the proximal end portion 32a of the distal end side tube member 32 up to a predetermined portion. The proximal end side tube member 31 has a distal end portion 31a and a distal end portion 31b and a distal end cylindrical portion 31c, and a proximal end portion (see FIG. (Not shown) is provided with a proximal end cylindrical portion 31d, and the distal end side tube member 32 has a distal end cylindrical portion 32c at the distal end portion (not shown), and a reduced diameter portion 32b and a proximal end cylindrical portion 32d at the proximal end portion 32a. Although it comprised so that it might comprise, if it is the structure which can attract the external air OA to the attracting part 30 favorably, it will not be specifically limited to this structure. For example, the following configurations (1-A) to (1-C) can be exemplified.

(1-A) For example, as shown in FIG. 9, a cylindrical proximal tube member 41 having no inner diameter change portion is connected to a cylindrical distal tube member 42 having no inner diameter change portion. It is also possible to configure the attracting part 40 by inserting up to a predetermined part in a state where a radial gap S is formed between the pipe members 41 and 42. Thereby, it is possible to form the attracting part 40 that attracts the external air OA using the Venturi effect with a very simple configuration.
In this case, the gap S is closed over the inner peripheral surface of the distal end portion (distal end opening, not shown) of the proximal end side tube member 41 and the inner peripheral surface of the distal end side tube member 42. A regulating member 43 as a check valve can be provided.

(1-B) Further, for example, as shown in FIG. 10, the base end portion 52a of the distal end side tube member 52 having the same configuration as the distal end side tube member 32 of the above-described embodiment does not have a portion where the inner diameter changes. It is also possible to configure the attracting portion 50 by inserting a cylindrical proximal end pipe member 51 up to a predetermined site with a radial gap S formed between the pipe members 51 and 52. In this case, in the distal end side tube member 52 of FIG. 10, the proximal end portion 52a is the proximal end portion 32a of the distal end side tube member 32, the enlarged diameter portion 52b is the enlarged diameter portion 32b, and the distal end tubular portion 52c is the distal end tubular portion 32c. Further, the base end cylinder part 52d corresponds to the base end cylinder part 32d.
As a result, the minimum inner diameter of the enlarged diameter portion 52b of the distal end side tube member 52 and the inner diameter of the distal end tubular portion 52c are equal to or larger than the inner diameter of the distal end portion (distal end opening, not shown) of the proximal end side tube member 51. Since the inner diameter of the proximal tube portion 52d of the side tube member 52 is smaller than the inner diameter, the distal end of the compressed air H flows through the distal tube member 52 after passing through the proximal tube member 51. It is possible to suppress a reduction in the speed of the air flow accompanying an increase in the cross-sectional area of the side pipe member 52, and it is possible to prevent a decrease in the pressure increase rate in the injector tube 15 due to the air flow.
In this case, the inner peripheral surface of the distal end portion (distal end opening, not shown) of the proximal end side tube member 51 is connected to the inner peripheral surface and the inner peripheral surface of the distal end tubular portion 52 c of the distal end side tube member 52. A regulating member 53 as a check valve can be provided so as to close the gap S.

(1-C) Further, for example, as shown in FIG. 11, the cylindrical distal end side tube member 62 having no portion where the inner diameter changes is similar to the tapered portion 31 b of the proximal end side tube member 31 of the above embodiment. It is also possible to configure the attracting part 60 by inserting the proximal end side pipe member 61 having the configuration into a predetermined part with a radial gap S formed between the pipe members 61 and 62. is there. In this case, the distal end portion 61a of the proximal end side pipe member 61 corresponds to the distal end portion 31a in the above embodiment, the tapered portion 61b corresponds to the tapered detail 31b, and there is no configuration corresponding to the distal end tubular portion 31c in the above embodiment. It becomes. This further increases the generation of negative pressure due to the Venturi effect in the vicinity of the attracting portion 60 formed in the portion communicating from the distal end side of the tapered portion 61b of the proximal end side tube member 61 into the distal end side tube member 62, The attraction force of the external air from the attracting part 60 into the injector tube 15 can be increased, and as a result, the pressure increase speed in the injector tube 15 can be further increased.

(2) In the above-described embodiment, the configuration in which the cross section of the injector tube 15 is cylindrical has been described. However, the configuration is not particularly limited to this configuration as long as the compressed air H can flow well. For example, various shapes such as a triangle, a rectangle, and a polygon can be employed.

(3) In the above embodiment, the bag filter 5 is used as the filter unit. However, any filter can be used as long as it is a filter that can satisfactorily collect the dust D in the dust-containing air G. . For example, it is possible to employ a ceramic filter as the filter unit. In this case, the ceramic filter is relatively hard, and even when the compressed air H is jetted inward, the ceramic filter hardly swells outward and becomes in tension like the bag filter 5. By making the pressure rise rate in the tube 15 extremely rapid, a pressure wave in an extremely high energy state is formed by the jet of the compressed air H from the jet hole 17 to the ceramic filter, and the pressure wave enters the ceramic filter. It is possible to improve the dust removal performance due to the propagation of.

  As described above, the compressed air in the ejection hole can be set to an extremely rapid pressure increase rate in the injector tube accompanying the opening operation of the on-off valve without causing problems such as an increase in the size of the device and an increase in the amount of air consumed. It was possible to provide a pulse type dust collector capable of forming a pressure wave in an extremely high energy state by jetting and improving dust removal performance by propagation of the pressure wave into the filter part.

DESCRIPTION OF SYMBOLS 1 Case 2 Dust-containing air introduction chamber 3 Purified air chamber 4 Partition wall 5 Bag filter (filter part)
6 Communication part 7 Compressed air ejection part 14 Header part (compressed air source)
15 Injector tube 15A Base end 15B Tip 16 Air on-off valve (on-off valve)
17 Ejection hole 30 Attraction part 31 Base end side pipe member 31a Tip end part 31b of base end side pipe member Taper (tip part of base end side pipe member)
32 distal end side pipe member 32a proximal end part 32b of distal end side pipe member expanded diameter part (proximal end part of distal end side pipe member)
A Pulse-type dust collector D Dust G Dust-containing air C Purified air H Compressed air OA External air P Base end region S Clearance X Maximum inner diameter of the base end tube member (base tube of the base end tube member Inside diameter)
Y Minimum inner diameter of the proximal end of the distal tube member (inner diameter of the distal tube portion of the distal tube member)
Z Maximum inner diameter of the proximal end of the distal tube member (inner diameter of the proximal tube of the distal tube member)

Claims (4)

A housing whose interior is partitioned into a dust-containing air introduction chamber and a purified air chamber by a partition wall;
Dust-containing air that is provided in each of a plurality of communicating portions that communicate the dust-containing air introduction chamber and the purified air chamber in the partition wall and flows from the dust-containing air introduction chamber side to the purified air chamber side. A filter unit having a plurality of filters for collecting dust contained therein;
A compressed air ejecting section for ejecting compressed air from the purified air chamber side to the dust-containing air introducing chamber side through the filter section and cleaning dust adhering to the filter section;
An injector tube having a proximal end connected to a compressed air source and closed at a distal end; and an on-off valve capable of intermittently supplying the compressed air from the compressed air source into the injector tube. A pulse-type dust collector provided with a plurality of nozzle tubes in the longitudinal direction of the injector tube, each of which includes a jet hole for jetting the compressed air supplied into the injector tube separately to the plurality of filters,
In the injector tube of the compressed air ejection part, in a proximal side region between a proximal end where the on-off valve is provided and a location where an ejection hole closest to the proximal end is provided among the plurality of ejection holes. And an attracting portion capable of attracting external air into the injector tube by an air flow of the compressed air supplied from the proximal end side toward the distal end side into the injector tube through the on-off valve. Pulse type dust collector. The injector tube is configured to include a proximal side tube member provided on the proximal side and a distal side tube member provided on the distal side,
The attraction portion is configured by the proximal end side tube member being inserted into the distal end side tube member in a state where a radial gap is formed between the proximal end side tube member and the distal end side tube member. The pulse dust collector according to claim 1.   The proximal end portion of the distal end side tube member has an enlarged diameter portion whose diameter increases toward the proximal end side, and the proximal end side tube member is inserted into the proximal end portion of the expanded distal end side tube member. The pulse type dust collector according to claim 2.   The pulse type dust collector according to claim 2 or 3, wherein a tip end portion of the base end side pipe member is formed with a taper that decreases in diameter toward a tip end side of the tip end portion of the base end side tube member.

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