JP2015013224A - Filter electrification treatment device and filter electrification treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cause charged particles to reach a depth part of a filter having a three-dimensional shape and uniformly electrifies the whole of the filter when electrifying the filter.SOLUTION: A filter electrification treatment device includes a drift electrode 2 (first electrode) to which a voltage is applied, a grid electrode 3 (second electrode), which is disposed above the drift electrode 2 to be opposite to the drift electrode 2, has an opening formed therein and an earth potential, a drift space 26 which is formed between the drift electrode 2 and the grid electrode 3 and has a filter 1 of an object to be treated installed therein while separated from the drift electrode 2 and the grid electrode 3, and a discharge part 25 which is disposed on the outside of the grid electrode 3 to be on the opposite side to the drift space 26, and supplies charged particles to the drift space 26 via the opening of the grid electrode 3 for electrifying the filter 1. The filter electrification treatment device performs electrification treatment for the filter 1 by means of the discharge part 25 while applying a high electric field to the drift space 26 by means of the drift electrode 2 and the grid electrode 3.

Description

  The present invention relates to a filter electrification apparatus and a filter electrification method, and in particular, in an electret filter used in an air conditioner, electret characteristics deteriorated due to use or washing when reused by washing after dust collection for a certain period. The present invention relates to a filter electrification processing apparatus and a filter electrification processing method for recovering the dust and recovering the dust collection rate.

  A non-woven electret filter is used as a medium performance filter for air conditioning. Non-woven electret filters have an electric polarization oriented and fixed inside and on the non-woven fibers, and in addition to aerodynamic collection mechanism, due to the effect of electrostatic force, excellent dust despite low pressure loss Realize the collection rate.

  In the non-woven electret filter, the sheet-like non-woven filter medium is charged under a corona discharge in the atmosphere at the time of manufacture, and the electric polarization is maintained in the filter medium. In general, electret filters are used by adhering thin, fine fiber charged filter media to thick aggregates with structural support by bonding, heat melting, or mechanical frictional force. There are front and back surfaces, and the aggregate on the back surface generally has a relatively low surface resistivity, so that it cannot hold charged charges and is difficult to charge. In order to reduce the pressure loss when inserting into a predetermined duct opening after bonding, the charged sheet-shaped filter medium is folded into a pleat shape and processed into a three-dimensional shape in order to increase the surface area of the filter medium. There are many. Then, in order to maintain a three-dimensional shape, it is common to use fixing means such as bonding with an adhesive (hot melt).

  By the way, an uncharged non-woven filter removes dust adhering at the time of use by washing with water, etc., so that the dust collection rate is recovered and can be reused. However, in the case of an electret filter, Since the electric polarization is lost due to the influence of the surfactant contained in the cleaning agent, the collection rate is lowered. In order to recover the initial collection rate, it is necessary to recharge the filter medium.

  As a conventional recharging technique, a method has been proposed in which a washed electret material is brought into close contact with a corona discharge electrode and introduced into an electric field in a flat state (see, for example, Patent Document 1).

  As another conventional recharging technique, there has been proposed a method in which a three-dimensional filter is irradiated with plasma in a vacuum to be recharged (see, for example, Patent Document 2).

JP-A-3-105907 (page 5) Japanese Patent Laying-Open No. 2003-210924 (page 2, FIG. 1)

  When a three-dimensional filter folded in a pleat shape is to be charged by the charging method disclosed in Patent Document 1 or Patent Document 2, when charged particles for charging are injected from discharge, charged particles of the filter are injected. Charged particles stay on the surface side first to form a reverse electric field, and charged particles injected later are prevented from entering the interior of the three-dimensional shape, making it difficult to charge the pleated valleys. . For this reason, the charging of the entire filter greatly loses uniformity, and the recharged state similar to that at the time of initial manufacture is not reproduced, and the desired collection performance cannot be obtained.

  In Patent Document 1, a three-dimensional filter is not intended. However, if the method of Patent Document 1 is to be used for a three-dimensional filter, the filter is previously used when the used and washed electret filter is regenerated. After the sheet is developed, corona discharge is performed so that the charging is applied to the entire filter surface. However, the adhesive part for maintaining the three-dimensional pleat shape of the filter is destroyed and the filter frame for attachment to the duct is destroyed / removed. The disassembly / assembly process is repeated, and the cost merit of reusing the three-dimensional electret filter is almost lost.

  When the method of Patent Document 2 is used, a vacuum is required, so that a vacuuming step and an air release step are required before and after the recharging process. When applied to a large amount of filter processing, the throughput of continuous processing is required. Greatly restrict. Alternatively, in order to recharge a large amount of filter at once by batch processing, a large-capacity vacuum chamber and a plurality of plasma electrodes are required, and an apparatus having extremely high introduction cost and operation cost is required.

  The present invention was made to solve such problems, and when charging the filter, charged particles can reach the depth of the three-dimensional filter, and the entire filter can be uniformly charged. An object of the present invention is to provide a filter charging device and a filter charging method.

  The present invention provides a first electrode to which a first voltage is applied, a second electrode which is provided on the upstream side of the first electrode so as to face the first electrode, has an opening, and is grounded And a discharge section for generating a discharge by applying a second voltage to a discharge electrode provided upstream of the second electrode to generate charged particles, the first electrode Supplying the charged particles accelerated by the first voltage through the opening of the second electrode toward the filter to be processed installed between the first electrode and the second electrode; It is a filter charging processing device that performs charging processing on the filter.

  The present invention provides a first electrode to which a first voltage is applied, a second electrode which is provided on the upstream side of the first electrode so as to face the first electrode, has an opening, and is grounded And a discharge section for generating a discharge by applying a second voltage to a discharge electrode provided upstream of the second electrode to generate charged particles, the first electrode Supplying the charged particles accelerated by the first voltage through the opening of the second electrode toward the filter to be processed installed between the first electrode and the second electrode; Since it is a filter electrification apparatus that performs the electrification process on the filter, when the filter is electrified, the charged particles can reach the deep part of the three-dimensional filter, and the entire filter can be uniformly charged.

It is sectional drawing which shows the structure of the filter electrification processing apparatus in Embodiment 1 of this invention. It is a perspective view which shows the structure of the medium performance filter after washing | cleaning in Embodiment 1 of this invention. It is a schematic diagram explaining the principle by which charging in the absence of an electric field in Embodiment 1 of the present invention is hindered. It is a schematic diagram explaining the principle by which uniform electrification is accelerated | stimulated by the electric field in Embodiment 1 of this invention. It is a schematic diagram explaining the principle which discharge generation in Embodiment 1 of this invention prevents charging. It is sectional drawing which shows the spacer of the filter electrification processing apparatus in Embodiment 1 of this invention. It is a bottom view explaining the installation position of the spacer of the electrification processing device in Embodiment 1 of the present invention. It is a figure explaining the charging result by the filter charge processing apparatus in Embodiment 1 of this invention. It is sectional drawing which shows the structure of the filter electrification processing apparatus in Embodiment 2 of this invention. It is sectional drawing which shows the structure of the filter electrification processing apparatus in Embodiment 3 of this invention. It is sectional drawing which shows the structure of the filter electrification processing apparatus in Embodiment 4 of this invention. It is a figure explaining the relationship between the space | gap thickness of the space | gap and discharge start voltage in Embodiment 1 of this invention.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram illustrating a filter charging apparatus 50 according to Embodiment 1 of the present invention. In FIG. 1, the filter 1 is a processing target for which the filter charging device 50 performs the charging process. The filter 1 can recover the dust collection rate by performing the charging process even if the dust collection rate once decreases due to water washing or the like. As shown in the perspective view of FIG. 2, the filter 1 includes a filter medium 20 made of a charged non-woven fabric and a metal or wooden filter frame 18 provided around the filter medium 20. The filter medium 20 is a three-dimensional filter obtained by folding a charged nonwoven fabric into a pleat shape, and the upper surface is used as a charged filter medium. 21 is a valley part of a pleat shape. The filter frame 18 is provided in the filter 1 for the purpose of maintaining the shape of the filter medium 20 and improving the mounting property. It is.

  As shown in FIG. 1, the filter electrification apparatus 50 includes a first electrode (hereinafter referred to as a drift electrode 2), a second electrode (hereinafter referred to as a grid electrode 3), a discharge high voltage electrode 4, and Discharge unit 25 composed of discharge ground electrode 5, fan and fan casing 6, prefilter 7, spacer 8, insulator 9, device housing 10, drift power supply 11, discharge power supply 12, discharge The high-voltage electrode connection 13, the drift electrode connection 14, the ground potential connection 15, and the ground 16 are configured.

  As shown in FIG. 1, in the filter electrification processing device 50, a drift electrode 2 and a grid electrode 3 having a ground potential are provided opposite to each other in a device box 10 having a substantially box shape and opened at the top. ing. The drift electrode 2 is a rod-shaped or plate-shaped electrode as shown in FIG. On the other hand, the grid electrode 3 is formed in a grid shape or a lattice shape (mesh shape, mesh shape) and has a large number of openings (through holes). Between the drift electrode 2 and the grid electrode 3, a space called a drift space 26 having a height of 50 to 200 mm is provided. The drift electrode 2 is provided on the insulator 9 and is electrically insulated from the apparatus housing 10 by the insulator 9. When performing the charging process, the filter 1 is placed on the drift electrode 2 through the spacer 8 made of an insulator. The filter 1 is placed apart from the grid electrode 3 so as to have a predetermined gap without contacting the grid electrode 3. Thus, the filter 1 is installed (electrically) isolated from the drift electrode 2 and the grid electrode 3. Since charged particles to be described later are supplied to the filter 1 via the grid electrode 3, the grid electrode 3 is on the upstream side of the filter 1. The position of the filter 1 in the drift space 26 is set slightly upward (upstream) from the center in the drift space 26 by appropriately selecting the height of the spacer 8. That is, the gap length (gap height) formed by the drift electrode 2 and the filter 1 is longer than the gap length (gap height) formed by the grid electrode 3 and the filter 1. This is for suppressing the discharge generated from the filter 1. An intermediate distance from the drift electrode 2 and the grid electrode 3, which is the counter electrode of the discharge from the filter 1, that is, the filter 1 is preferably located at the center position, but since the spacer 8 is present on the drift electrode 2 side, it is desirable. Since the possibility of creeping discharge of the spacer 8 is added, the drift electrode 2 side rather than the grid electrode 3 side means that the creeping distance (insulating distance) of the spacer 8 is increased to suppress discharge along the creeping surface of the spacer 8. It is desirable to separate them. Therefore, the filter 1 is installed on the grid electrode 3 side slightly above the center.

  A drift power source 11 is connected to the drift electrode 2 via a drift electrode connection 14. Grid electrode 3 is connected to ground 16 via device housing 10 and ground potential connection 15. A discharge portion 25 composed of the discharge high voltage electrode 4 and the discharge ground electrode 5 is disposed in a space located on the opposite side of the drift space 26 and upstream of the grid electrode 3. Although the discharge part 25 and the grid electrode 3 are separated from each other, they are arranged close to each other. Here, the discharge unit 25 employs a wire for the discharge high voltage electrode 4 in order to perform corona discharge. The discharge high voltage electrode 4 is connected to a discharge power source 12 through a discharge high voltage electrode connection 13. The discharge ground electrode 5 has a plate shape and is connected to the ground 16 through a ground potential connection 15. The discharge high-voltage electrodes 4 and the discharge ground electrodes 5 are alternately arranged in parallel and alternately to constitute a discharge unit 25 as a whole. The entire area of the discharge unit 25 is larger than the area of the upper surface of the filter 1, and the discharge unit 25 is disposed so as to cover the entire upper surface of the filter 1. A fan and a fan casing 6 (hereinafter simply referred to as fan 6) are provided in a space on the opposite side of the drift space 26 and on the outer side of the discharge unit 25 provided on the outer side of the grid electrode 3. It has been. The portion where the fan 6 is provided is an upper opening of the apparatus housing 10, the fan 6 is provided so as to close the upper opening, and a pre-filter 7 is provided on the outside of the fan 6. .

  Next, the operation of the filter charging device 50 will be described with reference to FIG. First, with respect to the drift electrode 2, a positive drift voltage having a voltage value not exceeding (the height of the drift space 26−the height of the filter 1) × (air breakdown voltage: 2.8 kV / mm) is applied. Applied by the drift power supply 11. The voltage value calculated by the above equation is a value set so as not to cause an air discharge in the drift space 26 even when the filter 1 or the filter frame 18 associated with the filter 1 exists. The drift voltage value is desirably 80% or less of the above calculated value in order to prevent discharge. The filter 1 installed between the drift electrode 2 and the grid electrode 3 is placed in a high electric field by the operation of applying the drift voltage. At this time, no steady current flows through the drift power supply 11 and there are almost no charged particles other than the surviving electrons in the drift space 26.

  Subsequently, a negative voltage is applied to the discharge high voltage electrode 4 from the discharge power supply 12. When the gap between the discharge high voltage electrode 4 and the discharge ground electrode 5 is 10 mm and a negative voltage of about −7 kV is applied, corona discharge occurs around the wire-shaped discharge high voltage electrode 4. Most of the charged particles generated by the corona discharge are absorbed by the plate-shaped discharge ground electrode 5, but negatively charged particles (negative ions of mainly oxygen, carbon dioxide, nitrogen oxide to which electrons and electrons are attached). And a part of the charged particles in which electrons are added to the fine dust in the gas phase can pass through the opening of the grid electrode 3 which is the lower boundary of the discharge unit 25 and enter the drift space 26. In particular, the grid electrode is set so that the distance between the discharge high voltage electrode 4 and the grid electrode 3 is equal to the distance between the discharge high voltage electrode 4 and the discharge ground electrode 5 plus a few mm. By installing 3, negatively charged particles are more efficiently transferred into the drift space 26. On the other hand, when the grid electrode 3 approaches the discharge high voltage electrode 4 such that the distance between the grid electrode 3 and the discharge high voltage electrode 4 is shorter than the distance between the discharge high voltage electrode 4 and the discharge ground electrode 5. The corona discharge is limited to the vicinity of the intersection of the discharge high-voltage electrode 4 and the grid electrode 3, the uniform discharge on the discharge high-voltage electrode 4 is not performed, spatial nonuniformity occurs in the charging effect, and the collection rate of the filter 1 The recovery effect will be greatly impaired. Therefore, in the present embodiment, the distance between the discharge high voltage electrode 4 and the grid electrode 3 is a distance equivalent to the distance between the discharge high voltage electrode 4 and the discharge ground electrode 5 plus several millimeters. The grid electrode 3 is installed so that it may become a distance.

  Subsequently, the fan 6 provided at the upper part of the discharge unit 25 is driven, and the inflow air 30 is taken into the inside of the device housing 10 by the fan 6 through the prefilter 7 provided in the opening of the device housing 10. At this time, the inflow air 30 passes through the pre-filter 7 and is removed and cleaned. The dust-removed air 31 obtained in this way is further sent toward the discharge unit 25 by the fan 6. The charged particles in the discharge unit 25 flow out from the discharge unit 25 toward the drift space 26 due to the advection effect due to the wind. At this time, extremely fine particles that are not captured by the prefilter 7 pass through the discharge unit 25 and are charged. Then, it flows out from the discharge part 25 to the drift space 26 together with the charged particles. Since the positive charged particles cannot move against the electric field, they cannot enter the drift space 26 beyond the grid electrode 3. On the other hand, some of the negatively charged particles are advected to the drift space 26. In this way, by sending the charged particle-containing air 32 to the drift space 26 using the fan 6, the flux (current) of negative charged particles entering the drift space 26 can be increased, and the charging efficiency can be increased.

  As a result of the above operation, negative charged particles from the discharge unit 25 move in a high electric field in the drift space 26, whereby a current on the order of 1 μA to 100 μA flows to the circuit including the drift power source 11, and Charged particles are accelerated and collided and fixed by an electric field. When the treatment is continued for several tens of seconds to several tens of minutes in this state, the filter 1 is charged and the dust collection rate is recovered.

  The role of the high electric field applied to the drift space 26 by the drift power supply 11 in the filter charging apparatus 50 according to the first embodiment will be described in detail with reference to FIGS. 3 and 4. FIG. 3 is a diagram for comparison with the first embodiment, and is a schematic diagram when the filter 1 is not placed under a high electric field. FIG. 3 shows a state in the course of recharging. The filter 1 is already charged with a certain amount of negatively charged particles 42. Since the pleated trough 21 of the filter 1 is not yet charged, negatively charged particles 42a are required for further charging. However, the negative charged particles 42 a are moved away from the filter 1 by receiving the Coulomb force 44 in the direction away from the filter 1 due to the influence of the electric field 41 formed by the negative charged particles 42 already charged on the filter 1. The track 45a will be taken. Therefore, the valley portion 21 having a pleat shape is not charged, and recovery of the collection rate is hindered.

  On the other hand, in FIG. 4 showing the case of the first embodiment, the drift electric field 40 is applied, and the direction of the drift electric field 40 is the same as the electric field 41 formed by the negative charged particles 42 charged on the filter 1. The reverse direction. At this time, since the drift electric field 40 has a high electric field strength, the electric field 41 formed by the negative charged particles 42 charged on the filter 1 is canceled, so that the filter 1 has a certain amount of negative charged particles 42. The Coulomb force 44 received by the negative charged particles 42b is directed toward the filter 1 and takes a trajectory 45b that collides with the filter 1. Therefore, the valley portion 21 having a pleat shape is also charged, and recovery of the collection rate proceeds.

  Next, the demerit that discharge occurs in the drift space 26 will be described with reference to FIG. In the filter 1 whose collection rate is restored by recharging, unipolar charges, here, negatively charged particles 42 are fixed on the surface of the filter 1. When the discharge 46 is generated in the drift space 26, not only the negative charged particles 42 c but also the positive charged particles 43 c are generated by the discharge 46. The charged particles 43c having the positive polarity take the orbits 45c attracted by the Coulomb force toward the charged valley portion 21 and neutralize by colliding with the negative charged particles 42, thereby weakening the collection rate recovery effect by charging. End up.

  For example, in a state where the discharge 46 is generated in the discharge unit 25, specifically, when the drift voltage 40 is applied and the discharge unit 25 is not discharged, the drift current measured by the drift power supply 11 has already been several. When the charging process is performed under the condition of 10 μA flowing, the collection rate of particles having a diameter of 0.2 to 0.3 μm, in which the effect of improving the dust collection rate (particle collection rate) due to charging is remarkable, is almost 0. It has been observed that In other words, the occurrence of discharge in the drift space 26 greatly hinders the collection rate recovery performance of the filter charging device. For this reason, in the first embodiment, the charging efficiency is improved by suppressing the occurrence of discharge in the drift space 26 by adopting the configuration described below. In addition, in addition, in the present embodiment, the discharge unit 25 is installed outside the drift space 26 and discharge is generated outside the drift space 26. However, the influence of the discharge outside the drift space 26 is affected. Prevents the positive charged particles 43 from penetrating into the drift space 26 by the potential barrier of the grid electrode 3, so that only the negative charged particles 42 can be supplied for charging. The sum is suppressed and the charging efficiency is improved.

  Possible causes of the discharge generation in the drift space 26 include the creeping discharge on the side surface of the spacer 8 and the spacer 8 and the filter 1 in addition to the above-described minute gap between the spacer 8 and the drift electrode 2. There is a possibility of discharging at a gap between the two. Therefore, for the purpose of suppressing discharge along the surface of the spacer 8, the present embodiment employs a spacer 8a or 8b having a shape in which the creeping distance (insulation distance) of the spacer 8 is extended as shown in FIG. The spacers 8a and 8b have grooves formed on the side surfaces in order to increase the creepage distance on the side surfaces. The groove of the spacer 8a has a substantially rectangular shape, and the groove of the spacer 8b is formed in a curved shape so as to draw an arc. In general, it is known that the creepage distance is suppressed by taking a distance of three times or more of the air discharge, and the creepage distance (side length) of the spacer 8a or 8b is the spacer 8a or 8b, respectively. It is preferable to make it a shape that is at least three times the height of.

  Next, the configuration of the first embodiment for the purpose of suppressing discharge due to a minute gap between the spacer 8 and the drift electrode 2 will be described. When a gap having a certain distance or more is generated on the contact surface of the spacer 8 with the drift electrode 2, a discharge is generated there. Therefore, the contact surface of the spacer 8 with the drift electrode 2 needs to have adhesion. . Therefore, in this embodiment, in order to make the spacer 8a or 8b adhere to the drift electrode 2, as shown in FIG. 6, a flexible silicone tape is attached to the lower surfaces of the spacers 8a and 8b as the adhesion body 80. . In the gap on the contact surface, since the filter 1 and the spacer 8 are dielectrics, electric field concentration occurs and discharge is likely to occur. Therefore, a close contact member 80 is provided as shown in FIG. 6 to form the spacer 8 and the drift electrode 2. It is desirable to make the voids to be minute amounts. FIG. 12 is a diagram showing the relationship between the gap thickness and the discharge start voltage in the present embodiment. In FIG. 12, a solid line 63 is an experimental value of the discharge start characteristic (Paschen curve) of air, and a dotted line 64 is the calculated value. The thickness of the gap formed by the spacer 8 and the drift electrode 2 corresponds to the left side of the minimum value (hereinafter referred to as Paschen minimum) of the air discharge start characteristic (Paschen curve) shown in FIG. It is necessary to form a gap having a sufficiently small voltage and a small thickness that does not cause discharge. Therefore, the close contact member 80 is provided on the lower surface of the spacer 8, and only a gap with a small thickness corresponding to the left side of the Paschen minimum (region where the discharge voltage rises) is formed between the spacer 8 and the drift electrode 2. Do not be. If the recharging atmosphere is atmospheric pressure (760 Torr), the gap thickness is desirably 1 μm or less because a gap of 1 μm or less sufficiently enters the left side of the Paschen minimum (a region where the discharge voltage increases). Therefore, the contact body 80 is attached by its adhesiveness, or the spacer 8 is screwed to the drift electrode 2 together with the spacer 8 to compress the contact body 80 so that the gap is less than a predetermined thickness (1 μm). The contact body 80 is not limited to the lower surface of the spacer 8, and the contact body 80 may be provided on the drift electrode 2 side.

  Next, the configuration of the first embodiment for the purpose of suppressing discharge due to the gap between the spacer 8 and the filter 1 will be described. In the present embodiment, as shown in FIG. 7, in the three-dimensional filter 1 configured with the filter frame 18, the spacer 8 does not contact the filter frame 18 but contacts the filter medium 20 portion. To be provided. This is because, particularly when the filter frame 18 is a metal frame, the filter frame 18 has a relatively high surface electric field strength in the drift space 26, so that the spacer 8 contacts the spacer 8 by avoiding the filter frame 18. The electric field strength of the portion can be reduced, the partial discharge caused by the spacer 8 is suppressed, the presence of the positive charged particles 43c generated by the discharge 46 in the drift space 26 is minimized, and the charge is neutralized. It can suppress that a collection rate falls.

  FIG. 8 shows an evaluation result obtained by performing recharging and recovery of the dust collection rate (particle collection rate) using the filter charging apparatus 50 according to the present embodiment. In FIG. 8, the horizontal axis represents the filter surface wind speed (m / s), and the vertical axis represents the particle collection rate (%). Further, the solid line 60 is a graph before cleaning, the solid line 61 is after cleaning, and the solid line 62 is a graph after cleaning and charging. In the evaluation of FIG. 8, an electret filter having a colorimetric method of 90% with a filter peak height (pleat height) of a filter folded in a pleat shape of approximately 40 mm was used as the filter 1. The electret is applied to a thin PP meltblown filter and is bonded to the PET aggregate with chemical bonds. When the particle collection rate of 0.3 μm center diameter was evaluated for this filter, as shown by the solid line 60, the collection rate was about 50% at a filter passing wind speed of 1 m / s. When this was washed with water containing a surfactant and the particle collection rate was evaluated, as shown by the solid line 61, the collection rate decreased to 10% or less even after sufficient drying. Therefore, the filter with a reduced collection rate was installed in a filter charging apparatus 50 set to a drift voltage of 40 kV, a discharge voltage of −7 kV, a discharge current of 3 mA, and a fan wind speed of 15 m / s, and charged for 10 minutes. As a result, the collection rate recovered to a little less than 40% as indicated by the solid line 62, and was recovered to about 70% to 80% of 50% before the cleaning. It should be noted that only a drift voltage of 40 kV is applied to the discharge power source 12 without generating a discharge voltage, and the drift current is 0.0 μA when no air is blown by the fan 6, and no discharge occurs in the drift space 26. I have confirmed. When the discharge is generated and the drift current without fan blowing by the fan 6 is 10 μA, and the fan blowing air speed is 15 m / s, the drift current increases to 30 μA. I found out.

  Note that the polarities of the drift power supply 11 and the discharge power supply 12 may be opposite to those described above. In this case, the filter 1 is charged with a positive charge, and the collection rate is recovered. Making the discharge power source 12 positive has the effect of suppressing ozone generation during discharge.

  As described above, the filter electrification apparatus according to the first embodiment has a drift sandwiched between the drift electrode 2 (first electrode) and the grid electrode 3 (second electrode) having an opening (opening). In the space 26, the three-dimensional filter 1 to be processed is installed separately from the drift electrode 2 and the grid electrode 3 through a spacer 8 made of an insulator, and a drift voltage is applied to the drift electrode 2 by a drift power source 11. The discharge high-voltage electrode 4 of the discharge unit 25 provided in the vicinity of the outside of the grid electrode 3 with the (first voltage) applied and the filter 1 installed in the drift space 26 placed in a high electric field. A negative voltage (second voltage) is applied to the electrode to generate a discharge to generate charged particles, and the grid electrode 3 (second electrode) has an opening (opening) toward the filter 1 to be processed. ) Supplies the charged particles are accelerated by the grid voltage (first voltage), and configured to perform charging processing for the filter 1. With this configuration, when the three-dimensional filter 1 is charged, the electric field 41 formed by the negatively charged charged particles 42 previously charged on the filter 1 is canceled by the drift electric field 40, The charged particles 42b for charging can reach up to 21. As a result, the filter 1 can be charged almost uniformly and the filter 1 can be recovered to a high collection rate. Therefore, in the present embodiment, as in the conventional device of the above-mentioned Patent Document 1, the three-dimensional filter can be recharged as it is without disassembling or assembling, so that the work process It is easy and cost-effective, and the maximum cost advantage of reuse can be expected. Moreover, compared with the conventional apparatus which recharges by plasma irradiation like the conventional apparatus of patent document 2 mentioned above, introduction cost and operation cost do not start, and an operation process is also simple. Further, in the present embodiment, by dividing the drift space 26 and the discharge part 25 by the grid electrode 3 in a grid shape, only unipolar charged particles can be introduced into the drift space 26. In this way, by supplying only unipolar (either negative or positive) charge for charging, neutralization of the charged charge can be suppressed and efficient charging becomes possible. In addition, by separating the filter 1 from the discharge high-voltage electrode 4, discharge between the discharge high-voltage electrode 4 and the filter 1 is prevented, and charged particles having a polarity opposite to that of the recharged charge are generated in the drift space 26. By limiting the presence, efficient charging can be performed without neutralizing recharging. Therefore, it is possible to achieve an effect that recovery of the collection rate by recharging the filter can be realized in a short time.

  Further, in the first embodiment, the filter 1 is installed slightly above the center of the drift space 26, so that the gap length formed by the drift electrode 2 and the filter 1 provided by the spacer 8 is the grid electrode 3 and the filter 1. It was configured to be longer than the gap length formed. In this way, by increasing the distance of the spacer 8 between the filter 1 whose potential has been lowered due to charging and the drift electrode 2, the discharge along the spacer 8 is suppressed, and the presence of reverse polarity charges is minimized. It is possible to increase the charging efficiency and to prevent the charge from being neutralized and the collection rate from being lowered.

  In the first embodiment, since the spacer 8 has a close contact surface with the drift electrode 2 and can adhere to the gap with the drift electrode 2 at 1 μm or less, the spacer 8 and the drift electrode 2 are used. 2 minimizes the minute air gap generated at the contact portion with 2 and suppresses partial discharge in the minute air gap. As a result, the presence of charged particles of opposite polarity in the drift space 26 can be minimized, the charged charge can be prevented from being neutralized and the collection rate can be suppressed, and the charging efficiency can be increased.

  In the first embodiment, since the side surface of the spacer 8 has a groove shape for extending the creeping distance, this configuration increases the insulating distance of the spacer 8 having a creeping structure that easily discharges. As a result, the discharge in the drift space 26 can be suppressed, the presence of reverse polarity charges can be minimized, and the collection rate can be suppressed from being neutralized due to neutralization of the charged charges.

  In the first embodiment, especially when the filter frame 18 attached to the filter 1 is a metal frame, the contact surface between the spacer 8 and the filter 1 is not in contact with the filter frame 18 that is a metal frame. With this configuration, the potential with which the spacer 8 is in contact can be lowered, the creeping discharge on the side surface of the spacer 8 can be suppressed, and the electric field on the contact surface between the filter 1 and the spacer 8 can be relaxed. Can be suppressed. Thereby, it is possible to minimize the presence of the reverse polarity charge and to prevent the charge from being neutralized and the collection rate from being lowered.

  Further, in the first embodiment, in the filter electrification processing apparatus, the fan 6 for blowing air is provided on the further outer side of the discharge unit 25 arranged on the outer side of the grid electrode 3, and directed toward the drift space 26 where the filter 1 exists. Therefore, the charged particles from the discharge unit 25 can be increased by the advection effect by the wind, and high-speed and efficient charging can be realized.

Embodiment 2. FIG.
FIG. 9 is a schematic diagram showing a filter charging apparatus 50A according to Embodiment 2 of the present invention. As shown in FIG. 9, the filter charging apparatus 50 </ b> A is provided with the drift space 26 as in the first embodiment, but is not provided with the spacer 8 shown in FIG. 1. Instead, the filter support 19 Thus, the point that the pleated filter 1 is suspended downward from the device housing 10 or the grid electrode 3 is different from the first embodiment. Further, the position of the filter 1 in the drift space 26 is slightly above the center in the height of the drift space 26 in the first embodiment, but in the present embodiment, in the height of the drift space 26. The difference from Embodiment 1 is that it is installed slightly below the center. Further, in the present embodiment, the fan 6 and the prefilter 7 shown in FIG. 1 are not provided, and instead, the opening 24 of the device housing 10 is provided with a lid 24. And different. Since other configurations are the same as those in the first embodiment, the same reference numerals are given and description thereof is omitted here.

  In the second embodiment, the filter support 19 is made of an insulator. Therefore, even when the filter frame 18 of the filter 1 is a metal frame, the filter frame 18 is supported so as to be electrically shielded from the apparatus housing 10. Further, the contact surface of the filter support 19 with the filter frame 18 is provided with the close contact body 80 as described with reference to FIG. 6, and the gap formed in the close contact surface is suppressed to a minute thickness that does not cause discharge. You may do it. As shown in the example of FIG. 9, for recharging, even when there is no fan 6, a lid 24 is applied to the upper part of the device housing 10, and only the potential relationship between the drift electrode 2 and the grid electrode 3 is obtained. Even if the movement 33 of the charged particles 42 of the negative charged particles 42 is generated, charging is possible although the charging efficiency is lowered. Further, not only in this case, but also in the present embodiment, a configuration in which a fan 6 and a pre-filter 7 are provided as shown in FIG. In that case, the charging efficiency can be improved by blowing the fan 6.

  Since the operation of the filter charging apparatus 50A is the same as that of the filter charging apparatus 50 of the first embodiment, the description thereof is omitted here.

  In the second embodiment, since the filter 1 is suspended by the filter support 19 made of an insulator, the structure causes discharge caused by the filter frame 18 even when the filter frame 18 is a metal frame. Since it is prevented by the filter support 19 and the spacer 8 is not provided, the generation of charged particles in the drift space 26 due to the creeping discharge of the spacer 8 can be suppressed, so that an efficient collection rate recovery effect is obtained. be able to.

  In FIG. 9, the side surface shape of the filter support 19 is described as a plane. However, the present invention is not limited to this, and in order to increase the creeping distance of the filter support 19, the spacers 8 a and 8 b in FIG. 6 are used. A groove similar to the groove formed on may be formed on the side surface of the filter support 19.

  As described above, in the second embodiment, as in the first embodiment, it is sandwiched between the drift electrode 2 (first electrode) and the grid electrode 3 (second electrode) having an opening. In the drift space 26, the three-dimensional filter 1 is installed separately from the drift electrode 2 and the grid electrode 3, and by applying a drift voltage, the filter 1 is placed in a high electric field. Since the filter 1 is charged by supplying charged particles from the discharge unit 25 provided in the vicinity of the outside, the same effects as those of the first embodiment described above can be obtained.

  Furthermore, in the second embodiment, the spacer 1 is not provided, and the three-dimensional filter 1 is placed in the drift space 26 surrounded by the drift electrode 2 and the grid-like grid electrode 3, and the filter support 19 made of an insulator. Is suspended from the apparatus housing 10 and is separated from the drift electrode 2, and charged particles are supplied from the discharge unit 25 disposed outside the drift space 26 on the grid electrode 3 side to charge the filter 1. . Since the spacer 8 is not provided in such a configuration, the generation of charged particles in the drift space 26 due to the creeping discharge of the spacer 8 can be suppressed. Can be prevented from being neutralized to lower the collection rate.

  In the second embodiment, the filter 1 is installed slightly below the center at the height of the drift space 26, so that the gap formed by the drift electrode 2 and the filter 1 provided by the filter support 19 is provided. The length was configured to be shorter than the gap length formed by the grid electrode 3 and the filter 1. This is because the spacer 8 is not provided, so that it is not necessary to consider the possibility of charged particle generation in the drift space 26 due to the creeping discharge of the spacer 8, and the creepage distance ( This is because the discharge in the drift space 26 is suppressed by increasing the insulation distance. In this embodiment, since the spacer 8 having a creeping structure that easily discharges is not provided, the partial discharge generated around the spacer 8 can be suppressed. Therefore, the presence of the reverse polarity charge is minimized, and the charged charge is medium. It can suppress that the collection rate falls by being summed.

  Further, in the present embodiment, the filter support 19 electrically shields the filter frame 18 of the filter 1, the contact surface in contact with the filter frame 18 has adhesiveness, and the gap between the filter frame 18 and the filter frame 18 is 1 μm or less. If possible, the minute air gap generated at the contact portion between the filter support 19 and the filter 1 can be minimized to suppress partial discharge in the minute air gap. As a result, the presence of charged particles of opposite polarity in the drift space 26 can be minimized, the charged charge can be neutralized, the collection rate can be suppressed from decreasing, and the charging efficiency can be increased.

  Further, in the present embodiment, in order to extend the creepage distance of the side surface of the filter support 19, the filter support 19 having a creeping structure that is easy to discharge is formed by making the creepage of the filter support 19 into a groove shape. Since the insulation distance of the body 19 can be increased, the discharge in the drift space 26 is suppressed, the presence of reverse polarity charges is minimized, and the charged charges are neutralized and the collection rate is reduced. Can do.

Embodiment 3 FIG.
FIG. 10 is a schematic diagram showing a filter charging apparatus 50B according to Embodiment 3 of the present invention. 10 and FIG. 1 is that a dehumidifying device 22 is provided between the pre-filter 7 and the fan 6 in FIG. Since other configurations are the same as those in the first embodiment, the same reference numerals are given, and the description thereof is omitted here.

  In the present embodiment, as shown in FIG. 10, the filter charging apparatus 50 </ b> B is provided with the drift space 26 and the discharge unit 25, and the pleated filter 1 is installed in the drift space 26, as in the first embodiment. To do. In the present embodiment, the inflow air 30 that flows in from the opening at the top of the device housing 10 is cleaned and removed through the prefilter 7 and then taken in, and then passed through the dehumidifying device 22 so that the inflow air 30 Dehumidify. In this way, the dust 6 and the dehumidified air 34 are sent to the discharge unit 25 by the fan 6, whereby the humidity of the drift space 26 can be lowered. As the level of dehumidification of the air 34, it is desirable that the relative humidity be 40% RH or less that can significantly increase the surface resistivity of the filter 1 particularly with respect to charging. Moreover, since the discharge of the discharge part 25 is obstructed when the humidity is high, the discharge part 25 can be easily discharged.

  10 shows a configuration in which the filter 1 is mounted on the drift electrode 2 via the spacer 8 slightly above the center at the height in the drift space 26 as shown in the first embodiment. However, the present invention is not limited thereto, and the filter 1 is suspended and supported by the filter support body 19 slightly below the center at the height in the drift space 26 as shown in the second embodiment. It may be configured.

  As described above, in the third embodiment, the same effect as in the first embodiment can be obtained, and further, the humidity in the filter electrification processing device 50B is removed by providing the dehumidifying device 22. By reducing leakage due to conduction of charged particles contributing to charging on the surface of the filter 1, an efficient collection rate recovery effect can be obtained.

Embodiment 4 FIG.
FIG. 11 is a schematic diagram showing a filter charge processing apparatus 50C according to Embodiment 3 of the present invention. 11 differs from the configuration in FIG. 1 in that, in FIG. 11, an expansion / contraction part 23 for adjusting the height of the grid electrode 3 is provided on the side surface of the apparatus housing 10. In the present embodiment, as described above, the expansion / contraction part 23 is provided on the side surface of the device housing 10, so that the drift electrode 2 and the grid electrode 3 are arranged according to the height (thickness) of the filter 1. The height of the drift space 26 between them can be made variable. Moreover, the expansion / contraction part 23 may be provided in all the side parts of the apparatus housing 10, or may be provided in a part of the side parts of the apparatus housing 10 as shown in FIG. Accordingly, in the configuration of FIG. 11, the spacer 8 c is installed at a slightly higher position from the center of the drift space 26 according to the height of the filter 1 and the height of the drift space 26. The height can be adjusted. As a method for adjusting the height of the spacer 8c, for example, a plurality of spacers 8c having different heights are prepared in advance, and the height of the spacer 8c can be changed by exchanging them, or the height can be adjusted. A flexible telescopic spacer 8c is used. Since other configurations are the same as those in the first embodiment, the same reference numerals are given, and the description thereof is omitted here.

  In the fourth embodiment, as shown in FIG. 11, the filter charging device 50C is provided with the drift space 26 and the discharge unit 25 as in the first embodiment, and the pleated filter 1 is placed in the drift space 26. Install in. Normally, the expansion / contraction part 23 is stationary at a predetermined length according to the reference value of the height of the filter 1, but when the height of the filter 1 installed in the drift space 26 is lower than the reference value, The expansion / contraction part 23 is contracted, and the height of the drift space 26 defined by the drift electrode 2 and the grid electrode 3 is kept low, and (the height of the drift space 26−the height of the filter 1) × (dielectric breakdown voltage of air: The drift voltage value limited by the value calculated at 2.8 kV / mm) is kept low. On the other hand, when the height of the filter 1 is higher than the reference value, the expansion / contraction part 23 is extended so that the filter 1 can be accommodated in the drift space 26. The height is reduced to about a value calculated by (height of 26−height of filter 1) × (air breakdown voltage: 2.8 kV / mm). At this time, the spacer 8 c adjusts the height of the spacer 8 c in accordance with the height of the filter 1 and the height of the drift space 26 so that the filter 1 is installed at a slightly higher position from the center of the drift space 26.

  11 shows a configuration in which the filter 1 is mounted on the drift electrode 2 via the spacer 8c slightly above the center at the height in the drift space 26. However, the present invention is not limited to this. As shown in the second embodiment, 1 may be configured to be suspended and supported by the filter support 19 slightly below the center at the height in the drift space 26. In this case, it is assumed that the filter support 19 has a configuration that can expand and contract according to the height of the filter 1.

  If the insulator 9 has a telescopic structure, the height of the drift space 26 can be adjusted according to the filter 1, but if the height of the filter 1 is high, the drift voltage increases, Since the insulator 9 needs to be shortened, it is not preferable in terms of insulation design.

  As described above, in the third embodiment, the same effect as in the first embodiment can be obtained, and further, the device housing 10 or the filter support body 19 as an electrode support body that supports the grid electrode 3 can be obtained. Since a part or all of the structure can be expanded and contracted and the height of the drift space 26 between the drift electrode 2 and the grid electrode 3 can be made variable according to the height of the filter 1, Corresponding to the filter 1 with different heights, the drift voltage is optimized regardless of the height of the filter 1, and the minimum required applied voltage can be selected for each height of the filter 1, which is unnecessary in the drift space 26. Efficient discharge can be suppressed, and an efficient collection rate recovery effect can be obtained.

  In addition, the filter electrification processing devices 50, 50A, 50B, and 50C in the first to fourth embodiments described above are described as electrification processing devices for recharging the cleaned filter and recovering the dust collection rate of the filter. did. When the filter is used, naturally, dust adheres to it, but the adhered dust can be removed by washing with water. However, the dust collection rate decreases due to the influence of the surfactant contained in the cleaning water and the cleaning agent during cleaning. Therefore, the filter electrification apparatus in the first to fourth embodiments is an apparatus for performing a electrification process on the filter in order to recover the reduced dust collection rate of the filter. However, the present invention is not limited to this, and it is naturally possible to use the filter charging device 50 according to the first embodiment for charging the filter at the time of manufacture. In that case, the same effect can be obtained. Needless to say.

  1 filter, 2 drift electrode, 3 grid electrode, 4 discharge high voltage electrode, 5 discharge ground electrode, 6 fan and fan casing (or fan), 7 prefilter, 8 spacer, 9 insulator, 10 device housing, 11 drift Power supply, 12 Discharge power supply, 13 Discharge high voltage electrode connection, 14 Drift electrode connection, 15 Ground potential connection, 16 Ground, 18 Filter frame, 19 Filter support, 20 Filter media, 21 Valley part, 22 Dehumidifier, 23 Stretching part, 24 lid, 30 inflow air, 31 dust removal air, 32 charged particle-containing air, 33 movement of charged particle, 40 drift electric field, 41 electric field due to charged particle on filter, 42 negative charged particle, 43 positive charged particle, 44 Coulomb force, 45 charged particle trajectory, 46 discharge, 50 filter charging Device, 80 adhesion body.

Claims (12)

A first electrode to which a first voltage is applied;
A second electrode that is provided on the upstream side of the first electrode so as to face the first electrode, has an opening, and is grounded;
A discharge unit that generates a charged particle by applying a second voltage to a discharge electrode provided on the upstream side of the second electrode to generate a charged particle; and
The charged particles accelerated by the first voltage through the opening of the second electrode toward the filter to be processed installed between the first electrode and the second electrode And a charging process for the filter. The filter is installed on the first electrode via a spacer made of an insulator,
The filter charging apparatus according to claim 1, wherein a gap length formed by the first electrode and the filter provided by the spacer is longer than a gap length formed by the second electrode and the filter. The filter charging apparatus according to claim 2, wherein a contact surface of the spacer with the first electrode has adhesiveness, and a gap between the spacer and the first electrode is 1 μm or less. The filter electrification processing apparatus according to claim 2, wherein a groove is formed on a side surface of the spacer. The filter is composed of a filter medium and a metal frame provided around the filter medium,
5. The filter electrification apparatus according to claim 2, wherein the spacer is installed in contact with the filter medium without contacting the metal frame of the filter. 6. The filter is installed by being suspended from the device housing or the second electrode by a filter support made of an insulator,
The filter charging apparatus according to claim 1, wherein a gap length formed by the first electrode and the filter provided by the support is shorter than a gap length formed by the second electrode and the filter. The filter charging apparatus according to claim 6, wherein a contact surface of the filter support with the second electrode has adhesiveness, and a gap between the support and the second electrode is 1 μm or less. The filter charging apparatus according to claim 6, wherein a groove is formed on a side surface of the filter support. 9. The fan according to claim 1, further comprising a fan that is provided further upstream of the discharge unit provided upstream of the second electrode and blows air toward the filter. Filter electrification device. A dehumidifying device for dehumidifying the air blown toward the filter by the fan;
The filter electrification processing device according to claim 9, wherein air having a relative humidity of 40% RH or less dehumidified by the dehumidifying device is blown toward the filter. The second electrode is supported by an electrode support;
The part or all of the electrode support that supports the second electrode has a stretchable structure, and the distance between the first electrode and the second electrode is variable. The filter electrification processing apparatus according to claim 1. A first electrode to which a first voltage is applied; a second electrode provided on the upstream side of the first electrode so as to face the first electrode, having an opening, and having a ground potential; Between which the filter to be treated is placed apart from the first electrode and the second electrode;
Applying the first voltage to the first electrode;
Applying a second voltage to a discharge electrode provided on the upstream side of the second electrode to generate a discharge, and generating charged particles,
The charged particles accelerated by the first voltage through the opening of the second electrode toward the filter to be processed installed between the first electrode and the second electrode A filter charging method for supplying and charging the filter.

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