JP2010244886A - Blowing type static eliminator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a static eliminator equipped with a structure that dusts contained in itself are not discharged outside. <P>SOLUTION: A cabinet 2 includes a flow passage 21 through which an air stream formed by a fan 3 passes. Inside the flow passage 21 and a space 22 inside the cabinet 2 in which the above high voltage power supply and a control board are fixed and arranged are blocked structurally or air-tightly, and air does not come and go through a wall demarcating the flow passage 21. The flow passage 21 is constituted of the inner surface 33 of a chassis 32 in which a cross-section in the diameter direction surrounding outside of the diameter direction of a blade 31 which the fan 3 has is nearly rectangular, and the inner surface 24 of a metallic duct 23 equipped with a cylindrical shape, and the chassis 32 and the duct 22 are air-tightly connected via an adaptor 7 equipped with an O-ring 8. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a blower type static eliminator.

  Various types of so-called blown static eliminators have been developed that generate positive and negative ions simultaneously by corona discharge and transport the generated ions toward the object together with the air blown by the fan to neutralize the static electricity charged. Yes. Such a blower type static eliminator has an electrode that performs corona discharge and a blower that generates an air current that carries ions generated by the corona discharge. In an assembly process of a semiconductor component or an electronic device, the component or the like It is used for the purpose of preventing destruction of parts and the like due to the discharge of charged static electricity.

  For example, Patent Document 1 that discloses an air ionizer states that “a part of the airflow passing through the housing 12 is defined by a cylindrical duct 22 disposed behind the air outlet passage 17 and in the front region of the housing. The duct 22 is attached to and supported by the front wall 16 of the housing.

  Patent Document 2 states that “the desorption unit 20 for a static eliminator has a support 4 that opens the vent 3, at least one discharge electrode 1 that is provided on the support 4 so as to protrude into the vent 3, and And a high-voltage power supply unit 2 for supplying power to the discharge electrode 1 ”.

US Pat. No. 6,118,645 JP 2004-253192 A

  In many cases, electronic equipment and semiconductor manufacturing equipment having a fine structure are installed in a clean room in order to avoid a deterioration in yield due to dust mixed into a manufactured product. In such a case, when using the blower type static eliminator as described above in the clean room, it is desired that the dust in the airflow conveyed from the static eliminator is as small as possible. However, the conventional blower type static eliminator has built-in control boards equipped with switches and the like in the casing. Usually, the inside of the casing where the control boards are arranged and the duct portion through which the airflow generated by the blower passes. And communicate. Further, when the duct portion is made of resin, the resin may be scraped off during maintenance to generate fine particles serving as a basis for dust. Therefore, during operation of the static eliminator, the internal pressure of the housing becomes negative due to the airflow of the blower, and dust and resin particles adhering to the control boards in the housing are carried away from the inside of the housing and directed toward the static elimination object along with the airflow May be transported. Therefore, in the conventional blower type static eliminator, it is necessary to periodically disassemble the static eliminator and clean the control boards.

  Therefore, the present invention provides a static eliminator having a structure that does not release dust or the like adhering to a control board without periodic cleaning, and does not itself become a dust generation source.

  In order to achieve the above object, according to one aspect of the present invention, at least one electrode for generating ions by corona discharge, and a blower unit that generates an air current that carries ions generated by the electrodes, A static eliminator having a flow path through which the air flow passes, wherein a wall surface defining the flow path is shut off in an airtight manner so that the air flow generated by the blower section does not pass through the wall surface. Electrical equipment is provided.

  In the static eliminator according to one aspect of the present invention, the static eliminator is shielded between the inside of the static eliminator in which the control boards are arranged and the flow path through which the air flow generated by the air blowing unit passes, thereby eliminating the static eliminator. It is possible to prevent dust and the like inside the static eliminator from being mixed into the airflow sent. Therefore, the cleanliness of the airflow can be maintained and managed at a high level without cleaning the inside of the static eliminator.

It is a figure which shows the front and side cross section of the static eliminator which concerns on embodiment of this invention. It is a figure which shows an example of the fan contained in the static eliminator of FIG. It is an enlarged view of the III section of FIG. It is a figure which shows the adapter which the static eliminator of FIG. 1 has. It is a figure which shows the state which combined the fan and the adapter. It is a figure which shows the attachment structure of an electrode. (A) It is a figure which shows the dimensional relationship around the adapter between a fan and a duct, Comprising: It is a figure which shows the state which the adapter and the electrode holder contact | abut, (b) An adapter and an electrode holder are O-rings It is a figure which shows the state separated only by the distance corresponding to the radius of. It is a figure which shows schematically the dimensional relationship of an electrode and a duct opening part. It is a graph which shows the discharge evaluation result at the time of changing the dimension d1 of FIG.

  Drawing 1 is a figure showing the front and side section showing one embodiment of the static eliminator concerning the present invention. In this embodiment, a DC type static eliminator will be described as an example. The static eliminator 1 includes a housing 2, a fan 3 (see FIG. 2) that is disposed in the housing 2 and generates an air flow in the direction of the rotation axis, and electrodes 4 a to 4 h (this embodiment) for generating ions by corona discharge. Then, four pairs of needle-like electrode needles are provided (total of 8 pairs), high-voltage power supplies 5a and 5b that are arranged in the housing 2 and send high voltage to the electrodes 4a to 4h, high-voltage power supplies 5a, And a control board 6 for controlling 5b. The static eliminator 1 may further include a grounded counter electrode (not shown) for generating a corona discharge between the electrodes 4a to 4d, but the components of the grounded static eliminator are opposed to each other. It can also be used as an electrode. The pair of electrodes (in the example shown, electrodes 4a and 4e, 4b and 4f, 4c and 4g, and 4d and 4h) are arranged at positions facing each other, and two of the four pairs (4a and 4e and 4c and 4g) Are electrically connected to the positive high voltage power source 5a, and the other two pairs of electrodes (4b and 4f and 4d and 4h) are electrically connected to the negative high voltage power source 5b. Corona discharge is generated between the electrode and the counter electrode by the applied voltage from these high voltage power supplies. Air ions are generated by the corona discharge, and the generated air ions are transported along with the air flow generated by the fan 3 toward an object (not shown) to be neutralized.

  As shown in the side sectional view of FIG. 1, the housing 2 has a flow path 21 through which an air flow generated by a blower, for example, a fan 3 passes. The inside of the flow path 21 and the internal space 22 of the housing 2 in which the above-described high voltage power supply and control board are fixedly arranged are cut off structurally or in an airtight manner, and pass through the wall that defines the flow path 21. Air can't come and go. In the present embodiment, the flow path 21 is disposed close to the fan 3 and the inner surface 33 of the chassis 32 (see FIG. 2) having a substantially rectangular radial cross section surrounding the radially outer side of the blade 31 of the fan 3. It is comprised from the inner surface 24 of the duct 23, and the chassis 32 and the duct 23 are airtightly connected through the adapter 7 provided with the sealing member (for example, O-ring 8 or packing with a rectangular cross section). The duct 23 is, for example, a cylindrical member, and may be made of a metal, or may be made of a resin whose inner surface is plated with a metal. When the member is made of a metal material, the metal material is preferably excellent in workability and corrosion resistance, such as stainless steel. In addition, by making the inner surface of the duct a metal, it is possible to improve the wear resistance by smoothing the inner surface and to make it easy to visually check the cleanliness of the inner surface. An excellent static eliminator can be provided.

  FIG. 3 is an enlarged view of a part III in FIG. 1, and FIG. The duct 23 is formed, for example, by welding a cylindrical metal member to the opening edge 12 of the front panel 11 (see FIG. 1) of the static eliminator 1 over the entire circumference, or integrated with the front panel 11 by press plastic working or the like. Thus, air leakage at the duct opening edge 12, that is, at the boundary between the duct 23 and the front panel 11, can be prevented, and dust in the internal space 22 of the housing 2 can be moved outside by the air flow of the fan 3. It is prevented from being conveyed. The duct 23 and the front panel 11 may be joined without a gap with an adhesive or a sealing material, or may be joined without a gap with an adhesive tape or the like. In either case, the opening edge 12 only needs to be kept airtight so that air does not leak from the opening edge due to the negative pressure generated by the airflow of the fan.

  When the duct 23 and the front panel are integrally formed by the above-described method, it is difficult to maintain the axial dimension of the cylindrical member with high accuracy, and the connection region between the duct 23 and the chassis 32 of the fan 3 is difficult. There is a possibility that a gap is generated at 25. Therefore, an adapter 7 as shown in FIG. 4 is used to prevent air from coming and going in the connection area.

  As shown in FIG. 2 when the fan 3 is viewed from the downstream side in the air flow direction, the chassis 32 of the fan 3 has at least one rib for fixing the motor (in the illustrated example, three ribs 34a and 34b) extending from the outside in the radial direction toward the center. And 34 c), and one of the ribs (rib 34 c) has a guide function for guiding the fan cable 35 that supplies power to the fan 3. On the other hand, the adapter 7 is made of an insulating material such as an insulating resin, and has an outer dimension substantially the same as that of the fan 3 when viewed in the axial direction of the fan 3 as shown in FIG. As shown in FIG. 5, the adapter 7 is disposed so as to overlap the fan 3 when the static eliminator is assembled, and ribs 71a and 71b that come close to or abut against the ribs 34a, 34b, and 34c at that time, respectively. And 71c. In particular, the rib 71c protects the fan cable 35, and dust or the like adhering to the cable 35 is mixed into the air flow of the fan 3, or dust or the like inside the housing is passed through a passage through which the cable 35 is wired. Is provided with a function as a cover member that forms a closed space in cooperation with the rib 34 c so that the air does not enter the air flow of the fan 3. As shown in FIG. 3, the chassis 32 and the adapter 7 of the fan 3 are in contact with each other in the connection region 25, but the contact surfaces of the chassis 32 and the adapter 7 are relatively highly accurate. Since it can be processed into a flat surface, it is possible to prevent air from leaking between the two even when they are in contact with each other. However, for more reliable airtightness, a soft gasket or the like may be interposed between the two. Alternatively, both may be joined with an adhesive, a sealing material, an adhesive tape or the like without a gap.

  Next, a connection form between the adapter 7 and the duct 23 will be described. As shown in FIGS. 3 and 4, the adapter 7 has a receiving portion (circular recess in the illustrated example) that receives an O-ring 8 for airtightly joining to one end 231 of the duct 23 when the static eliminator is assembled. 72. The receiving portion 72 includes a ring-shaped bottom portion 73 having an inner diameter substantially equal to the inner diameter of the duct 23 and an outer diameter substantially equal to the outer diameter of the O-ring 8, and is substantially perpendicular to the bottom surface from the outer periphery of the bottom portion 73. When the electric appliance is assembled, it is defined by a ring-shaped peripheral portion 74 extending to the opposite side (that is, the duct side) from the fan 3. That is, as shown in FIG. 3, the receiving portion 72 opens in the axial direction of the duct 23 and on the duct side. Therefore, the O-ring 8 received by the receiving portion 72 has an inner peripheral portion on the outer surface 26 of the duct 23. The outer peripheral part comes into contact with the peripheral edge 74 of the adapter 7. That is, the outer wall surface of the duct 23, the bottom portion and the peripheral portion of the adapter 7 cooperate to define a receiving groove for receiving the O-ring 8. According to such a configuration, even if the end portion 231 of the duct 23 does not come into contact with the bottom portion 73 of the adapter 7 due to the axial dimensional accuracy of the duct 23, the airtightness of the connection region 25 is achieved by the O-ring 8. Kept.

  As in the case of the static eliminator according to the present embodiment, when the duct 23 is made of metal, if the plate thickness is appropriately selected (for example, t = 1.2 mm when the duct is made of stainless steel), Sufficient strength and rigidity can be provided. Hereinafter, the electrode fixing mode will be described with reference to FIG.

  FIG. 6 is a view including a top view of the electrode holder 9 for fixing each electrode (4a in the illustrated example) to the duct 23, and a cross-sectional view of the electrode holder 9 attached to the metal duct 23. The electrode holder 9 includes a pedestal 91 made of an insulating material such as an insulating resin, a seal member (for example, an O-ring 92 or a packing having a rectangular cross section) received in an annular groove 911 formed in the pedestal 91, and a pedestal 91. And fixing means 93 such as screws for fixing to the duct 23. The duct 23 is provided with an opening 27 having an opening diameter d1 smaller than the outer diameter of the O-ring 92. The pedestal 91 is configured such that the O-ring 92 surrounds the opening 27 from the outer surface 26 side of the duct 23. And is attached to the outer surface 26 by fixing means 93. The electrode 4a is tightly fixed to the pedestal 91 by press fitting or the like so as to extend substantially perpendicularly from the center of the annular groove 911 or the O-ring 92 to the central axis of the duct 23. At this time, as shown in the side sectional view of FIG. 6, an O-ring 94 or a sealing material may be disposed between the electrode 4a and the base 91 so that air does not leak from the periphery of the electrode.

  The O-ring 92 is disposed between the duct portion that defines the opening 27 and the bottom surface of the annular groove 911, and is pressed against the duct portion that defines the opening 27 over the entire circumference. Thereby, the opening part 27 is sealed, and the entrance / exit of the air through the opening part 27 is prevented. In this way, even if it is a curved surface such as a duct side surface, air leakage can be reliably prevented by a sealing member such as an O-ring. The relationship between the opening diameter (d1) of the opening 27 of the duct 23 and the shortest distance d2 between the peripheral end of the duct 23 defining the opening and the outer peripheral portion of each electrode will be described later.

  As shown in FIG. 6, the pedestal 91 of the electrode holder 9 can also be used as a holding means for the O-ring 8 provided between the adapter 7 and the duct 23 described above. That is, by disposing the adapter 7 and the holder 9 so that the upper end surface 741 of the peripheral edge 74 of the adapter 7 and the side end 912 of the base 91 of the electrode holder 9 are close to each other, the O-ring 8 can be detached from the adapter 7. Can be prevented. 7A, the upper end surface 741 of the peripheral edge 74 of the adapter 7 and the side end 912 of the pedestal 91 of the electrode holder 9 may be in contact with each other, or may be separated from each other by a predetermined distance. . However, the predetermined distance is preferably equal to or less than the radius R of the radial section of the O-ring 8 in order to reliably prevent the O-ring 8 from being detached, as shown in FIG. In order to maintain the airtightness due to the O-ring 8, the distance between the end face of the duct end 231 and the bottom face 731 of the adapter 7 is preferably not more than the radius R.

  The material of the above-described O-rings 8 and 92 is not particularly limited, but a fluorine-based material having shrinkage and solvent resistance is preferable. However, if solvent resistance is not required, an inexpensive nitrile rubber, for example, can be used.

  When the electrode 4a is to be fixed to the duct 23 made of at least the inner surface 24 as shown in FIG. 6, the dielectric breakdown between the electrode 4a and the metal portion of the duct 23 (here, the duct inner surface 24). In order to prevent this, it is preferable to provide a non-conductive portion or space made of an insulating resin or the like around the electrode 4a. Therefore, in the example of FIG. 6, an annular groove 911 is provided so as to form an insulating circular region 913 having a diameter d1 centered on the electrode 4a, and an opening 27 having a size corresponding to the insulating circular region 913 is formed in the duct 23. Is provided.

  The dimension d2 shown in FIG. 6 and FIG. 8 represents the shortest distance between the metal duct 23 and each electrode (electrode 4a in the illustrated example). Insulation breakdown may occur, corona discharge does not occur at the electrode tip, and a predetermined amount of ions may not be generated. Therefore, corona discharge evaluation was performed when the dimension d2 was changed under the conditions described below.

  As shown in FIG. 1 and FIG. 6, four insulating resin holders for positive electrodes (4a, 4c, 4e, 4g) and four insulating resin holders for negative electrodes (4b, 4d, 4f, 4h) They were alternately fixed at equal intervals (45 ° intervals) to a stainless steel cylindrical duct having a diameter of 115 mm. As schematically shown in FIG. 8, the height h of each electrode tip from the inner surface 24 of the duct 23 was 9 mm. The diameter of each electrode was 1.5 mm, and the tip angle was 20 degrees. The opening diameter d1 of the duct 23 to which the insulating resin holder to which the electrode was attached was fixed was four conditions of 10 mm, 8 mm, 7 mm, and 6 mm. A voltage of +4.5 kilovolts was applied to the positive electrode and a voltage of -3.0 kilovolts was applied to the negative electrode, and corona discharge evaluation was performed for each of the above four conditions.

  As a result of the discharge evaluation, stable corona discharge occurred when the opening diameter d1 was 10 mm, 8 mm, and 7 mm, but when the opening diameter was 6 mm (that is, when the shortest distance between the electrode and the metal duct was 2.25 mm). ), Dielectric breakdown occurred between the electrode and the metal duct, and no corona discharge occurred. Therefore, the ion balance stability of the ion output was measured for aperture diameters d1 of 10 mm, 8 mm, and 7 mm (that is, d2 = 4.25 mm, 3.25 mm, and 2.75 mm). The measurement was performed according to ANSI standard EOS / ESD S3.1-1991 Location: TP02.

  FIG. 9 is a graph showing the results of measuring the ion balance stability when the aperture diameter is 10 mm, 8 mm, and 7 mm based on the ANSI standard. The graph shows the variation of ion balance with respect to time during measurement for each aperture diameter, and further, three times the standard deviation of ion balance at each aperture diameter, that is, 3 sigma is added. In addition, when the same measurement was performed in a state where ions were not output from the static eliminator, 3 sigma was 3.01.

  Example 1 described above shows an evaluation result based on a change in the shortest distance d2 between the metal duct 23 and each electrode (the electrode 4a in the illustrated example), but the height of the electrode is equal to the dimension d2 or from d2. If the distance is short, the distance between the tip of the electrode and the peripheral edge of the duct opening (shown as d3 in FIG. 8) may be a factor that greatly affects the presence or absence of dielectric breakdown and the variation in ion balance. . The voltage applied to each electrode can also affect the occurrence of dielectric breakdown.

  In the above-described embodiments, the DC type static eliminator has been described as an example. However, the present invention can be similarly applied to an AC type static eliminator. In the AC type static eliminator, for example, one electrode may be provided. Moreover, all the electrodes can be electrically connected to one AC power supply, and corona discharge is performed between the electrodes and a part of the static eliminator having the ground potential.

  In the static eliminator according to the present invention, a structure that shuts off a duct through which an air stream containing ions (ion flow) passes and an internal space of a housing in which the control boards of the static eliminator are installed is provided inside the static eliminator. The cleaning degree of the static eliminator can be managed by performing the maintenance of only the duct portion without considering the influence of the dust blowing out or existing. Further, by making the duct portion made of a metal having high corrosion resistance such as stainless steel, it is possible to clean it with a solvent such as alcohol. In addition, by adopting a structure in which the holder to which the electrode is fixed is fixed to a metal duct, the duct can have two functions as a flow path through which an ion flow passes and a fixing part of the holder. It is possible to contribute to miniaturization and weight reduction.

DESCRIPTION OF SYMBOLS 1 Charger 2 Housing 21 Flow path 22 Internal space 23 Duct 25 Connection area 27 Opening part 3 Fan 4a-4h Electrode 5a, 5b Power supply 6 Control board 7 Adapter 8, 92 O-ring 9 Insulating electrode holder 91 Base 93 Fixing means

Claims (5)

A static eliminator having at least one electrode for generating ions by corona discharge, a blower unit that generates an air flow for carrying ions generated by the electrode, and a flow path through which the air flow passes,
The wall surface that defines the flow path is a static eliminator that is shut off in an airtight manner so that the airflow generated by the blower does not pass through the wall surface.   At least a part of the wall surface defining the flow path is an inner surface of a cylindrical member having at least an inner surface made of metal, and the cylindrical member is at a boundary between the cylindrical member and the front panel of the static eliminator. The static eliminator according to claim 1, configured to prevent air from leaking.   An adapter is disposed between the cylindrical member and the air blower, and the adapter and the cylindrical member cooperate to abut against both the adapter and the cylindrical member so that the adapter and the cylinder are in contact with each other. The static eliminator of claim 2, wherein the static eliminator defines a groove that receives a seal member that ensures airtightness between the ridges.   The static eliminator according to claim 2 or 3, wherein the at least one electrode is airtightly fixed to the cylindrical member by an insulating electrode holder so as not to be electrically connected to the metallic cylindrical member. .   The static eliminator of Claim 4 whose shortest distance between the part which consists of a metal in the said cylindrical member, and each electrode is 2.25 mm or more.

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