JPH0315316B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pipe-type static eliminator for neutralizing static electricity of powder or liquid traveling in a pipe.

It is well known that when various powders or liquids with high electrical resistance are transported through pipes, a large amount of static electricity is generated due to the collision of these objects with the inner walls of the pipes, resulting in various disasters. ing. On the other hand, if it were possible to install a static electricity remover to neutralize static electricity in the pipe during pipe transportation, it would be extremely economical without changing the transport route and requiring no special location. Such a static eliminator does not exist, and therefore, conventionally, a known static eliminator has been installed outside the outlet of conduit transportation and used to neutralize static electricity. Therefore, in the past, highly charged powder etc. adhered to the middle of the pipe line due to electric force and obstructed transportation, and such adhered powder was suddenly separated and discharged as agglomerates with large particle diameters. In the case of powder coating, etc., quality problems often occur.

In response to this, the present inventor provided an insulating cylindrical body in the conduit in another invention "pipe type static eliminator" (Japanese Patent Application Laid-Open No. 58-57296), and provided a corona discharge electrode in contact with the inner wall of the insulating cylinder. At the same time, a planar induction electrode is provided in contact with the outer wall so as to cover the part facing the corona discharge electrode, and an alternating current high voltage is applied between both electrodes, and the electrode is applied along the dielectric surface from the corona discharge electrode. After generating an alternating current creeping corona discharge to form a planar plasma ion source containing abundant positive and negative polar ions, a charged object entering the insulating cylinder from the upstream side is
We proposed a ``tube-type static eliminator'' that uses the Coulomb attraction exerted by the charge to attract and extract ions of opposite polarity from the plasma ion source, thereby neutralizing the charge on the charged object.

This static eliminator has extremely excellent static eliminator performance, but since a cylindrical planar plasma ion source with a concentric structure is installed inside the tubular static eliminator body, it requires an insulating mold, etc., and its structure is significantly deteriorated. It has the drawbacks of being complicated and extremely expensive.

SUMMARY OF THE INVENTION An object of the present invention is to provide a new pipe-type static eliminator which has a simple structure and is inexpensive, which compensates for the drawbacks of the above-mentioned pipe-type static eliminator. However, the term "pipe type" as used herein is not necessarily limited to those having a circular cross section, but generally refers to those having rectangular, square, polygonal, round, and other cross-sectional shapes.

Therefore, the present invention aims to achieve the above-mentioned purpose by arranging one or an appropriate number of planar plasma ion source generators of any shape in a pipe so that the plasma generating part thereof is exposed to the airflow in the pipe. Achieve by doing.

That is, the novel pipe-type static eliminator according to the present invention has a pipe main body for allowing a charged object to pass through, and a plasma generating section in the pipe main body that controls the flow of the charged object passing through the pipe. It has an appropriate number of planar plasma ion source generators arranged so as to be exposed to the path, and is attached to one side of at least one planar dielectric layer as the planar plasma ion source generators. or a suitable number of corona discharge electrodes are provided in close proximity, and a planar induction electrode is provided on the other side of the planar dielectric layer in contact with the dielectric layer so as to cover the portion facing the corona discharge electrode. , applying an alternating current high voltage between both electrodes and generating a creeping corona discharge from the corona discharge electrode along the surface of the dielectric layer, thereby forming a planar plasma ion source;
Further, it is characterized by having an AC high voltage power source for applying an AC high voltage between the corona discharge electrode and the induction electrode.

In this case, the planar shape of the planar dielectric layer is not limited to just a planar shape, but includes cylindrical, curved, polygonal, and any other suitable shapes. As for the material, any suitable organic or inorganic insulating material can be used, and inorganic insulating materials such as glass, ceramic, and mica are particularly suitable because they are resistant to corona deterioration. The corona discharge electrode is preferably made of a metal material with high corona resistance, such as tungsten, platinum, stainless steel, or nickel, and preferably has a thin or strip-like shape, which is placed on the surface of the dielectric layer. The two ends may be fixed and stretched so that they are in contact with each other, or they may be bonded onto the dielectric surface with a suitable adhesive. The pattern of the linear corona discharge electrode may be formed by printing a thick film of ink on the surface of the dielectric layer, and the pattern may be fired at a high temperature to form the corona discharge electrode. In addition, as a planar induction electrode formed in contact with the opposite surface of the dielectric layer, a suitable metal foil such as aluminum foil may be adhered, but a suitable conductive paint may be applied on the dielectric surface. It is also possible to use a method of forming the film by using thick film printing, a method of forming and firing the film by thick film printing, or a method of forming a metal thin film by vapor depositing an appropriate metal. Additionally, the backside of the device can be covered with an insulating layer to ensure safety. The same wave number of the AC high voltage may be either commercial frequency or high frequency, but especially 1K.
It is preferable to use a high frequency of Hz or higher because a good plasma ion source can be formed. Further, as the waveform of the AC high voltage, not only a sine waveform but also a pulse waveform, a pulsating waveform, and any other appropriate waveform can be used.

Further, as the pipe main body, a pipe made of metal may be used, but a pipe made of any suitable material such as plastic, FRP, rubber, rubber cement, glass, ceramic, etc. may also be used. In addition, since powder may accumulate on the surface of the planar plasma ion source generator during use and inhibit plasma generation, a scraping device may be built in to mechanically remove the powder. A hammering device that slides a group of corona discharge electrodes onto the dielectric surface to scrape off powder, provides a nozzle to blow it away with a jet of compressed air, and causes it to peel off by applying a mechanical shock. Alternatively, a vibration device may be provided. Further, the side wall of the conduit may be structured so that it can be opened, closed, or removed so that the plasma ion source generator inside can be easily inspected and cleaned. Furthermore, flanges or the like may be provided at both ends of the conduit for connection to the transport conduit.

FIG. 1 is a perspective view showing an example of a planar plasma ion source generator used for pipe-type static elimination according to the present invention, and FIG. 2 is a cross-sectional view thereof. In the figure 1
is a rectangular flat dielectric layer made of high-purity alumina ceramic or heat-resistant glass, and is formed on the surface 2 by the above-mentioned thick film printing technique and is fired to a width of about 1 mm.
Strip-shaped corona discharge electrodes 3, 4, 5, and 6 having a thickness of about 100 μm are provided, and one end thereof is connected to a thick film conductive wire 7 for connection. 8 is a planar induction electrode having a thickness of about 10 μm formed and fired using the same thick film printing technique on the back surface 9 of the dielectric layer 1, and facing the corona discharge electrodes 3 to 6 disposed on the surface 2; and has a shape and area that covers the entire area of the opposing portion, and its outer periphery 10 is equal to the outer periphery 11 of the dielectric layer 1.
It is arranged so that it is at least about 3 to 5 mm inside of the The back of the induction electrode 8 is covered with an insulating layer 12 for safety. 12 may be made of an epoxy resin layer, FRP layer, glass layer, etc., and may be bonded to 8 and 9.
When high-purity alumina ceramic is used for the dielectric layer 1, the insulating layer 12 itself can also be made of high-purity alumina ceramic, and can be laminated and fired with the insulating layer 1 and formed integrally. 13 is the AC high voltage power supply and terminal 1
4, 15 and conductive wires 16, 17 between the corona discharge electrodes 3 to 6 and the induction electrode 8.
An AC high voltage is supplied through the corona discharge electrodes 3 to 6, thereby generating an AC creeping discharge along the surface 2, which generates a planar plasma ion source containing abundant positive and negative ions. It is formed along the surface 2 of the dielectric layer 1.

FIG. 3 is a perspective view showing another example of the planar plasma ion source generator used in the present invention. are glued together to form a monolithic structure. Alternatively, 18 and 19 may be constructed by laminating and firing high-purity alumina ceramics and then integrally forming them. Concave portions 22, 23, 24, 25 and 22', 2 are formed at regular intervals on both peripheral edges 20, 21 of 18, 19, respectively.
3', 24', 25', and a single thin tungsten wire 26 is spirally wound on the outer surface of both of the integral structures 18 and 19 so as to fit into these recesses. They are fixed at both ends 27 and 28, thereby forming linear corona discharge electrodes that are arranged in parallel and at equal intervals in contact with both outer surfaces of the dielectric layers 18 and 19. Therefore now,
When an AC high voltage is supplied between the linear corona discharge electrode 26 and the planar induction electrode 8 via the terminals 14, 15 and the conductive wires 16, 17, the flat dielectric layers 18, 19 formed as an integral structure are formed. A planar plasma ion source is formed on both outer surfaces of.

FIG. 4 is a side view of another example of the planar plasma ion source generator used in the present invention. In the figure, 29 is a cylindrical dielectric layer made of glass or ceramic, and a strip-shaped metal corona discharge electrode 30 is spirally wound around the outer surface of the dielectric layer, and is fixed to 29 at both ends 31 and 32. . 33 is a planar induction electrode made of conductive paint applied to the inner surface of the cylindrical dielectric layer 29;
9 is a cap made of a conical insulator attached to one end (upstream side) of the cap to prevent adhesion of fluid powder. Reference numeral 35 denotes a bushing made of an insulator attached to the other end (downstream end) of 29, through which a conducting wire 17 connected to the terminal 15 passes through the center and is connected to the induction electrode 33. Now terminals 14, 15
Linear corona discharge electrode 3 is connected via twisted conductors 16 and 17.
By supplying an AC high voltage between the cylindrical dielectric layer 29 and the planar induction electrode 33, a cylindrical plasma ion source can be formed on the outer surface of the cylindrical dielectric layer 29.

FIG. 5 shows a perspective view of an embodiment of the novel pipe-type static eliminator according to the present invention. Reference numeral 36 denotes a conduit main body having a rectangular cross section, and in contact with the inner sides of both sides 37 and 38, planar plasma ion source generators 39 and 40 shown in FIG. 1 are equipped with corona discharge electrodes. The plasma generating parts 41 and 42 are connected to the pipe main body 3
The terminals 1 and 6 are arranged so as to face the fluid passages 43 inside the terminals 1 and 1, respectively, and are
Plasma of the planar plasma ion source generators 39, 40 is generated by supplying an AC high voltage between the corona discharge electrodes 3 to 6 and the planar induction electrode 8 through the conductors 16, 17 and the planar plasma ion source generators 39, 40. Generation part 41,
42 to form an active planar plasma ion source. Therefore, when the pipe main body 36 is inserted and connected in the middle of the pipe transport route for powder, granular material, fluid, etc., and a charged object is introduced into the fluid passage 43 in the inlet 44, the electric charge will be reduced. The object is immediately neutralized and neutralized by ions of opposite polarity supplied from the plasma ion source, and the object that has lost its charge is discharged from the outlet 45.

In this example, it goes without saying that the planar plasma ion source generator shown in FIG. 1 may be attached not only to the left and right side walls but also to the inner surfaces of the upper and lower side walls.

FIG. 6 is a perspective view of another embodiment of the pipe-type static eliminator according to the present invention. Reference numeral 46 denotes a pipe main body having a circular cross section, and a planar plasma ion source generator 47 shown in FIG. 3 is installed in the center of the pipe main body so as to bisect the fluid passage 43 inside the pipe main body. Therefore, if the flanges 48 and 49 at the inlet and outlet portions are used to insert and connect the 46 to a pipeline transport path for powder, granules, fluid, etc., and a chargeable object is introduced into the fluid passage 43 within the 46 from the inlet 44. , 4
The charges are neutralized and eliminated by planar plasma ion sources formed on both sides of the ion beam 7, and then discharged from the outlet 45.

FIG. 7 shows a longitudinal sectional view of another embodiment of the pipe-type static eliminator according to the present invention. Reference numeral 46 designates a pipe body having a circular cross section, 44 an inlet thereof, 45 an outlet thereof, 48 an inlet flange, and 49 an outlet flange. Reference numeral 50 denotes a cylindrical planar plasma ion source generator shown in FIG. 4 disposed along the pipe axis of the pipe main body, which is supported by metal supports 51 and 52 and fixed to the pipe main body 46. has been done. The terminal 14 is now connected to the linear corona discharge electrode 30 of the cylindrical planar plasma ion source generator 50 via the conductor 16 and the metal support 52, and the terminal 15
is connected to the planar induction electrode 33 inside 50 by a conductive wire 17 via an insulating bushing 53 penetrating the conduit main body and an insulating bushing 35 at the downstream end of 50. Therefore, when an AC high voltage is applied between the terminals 14 and 15, an active planar plasma ion source is formed on the outer surface of the cylindrical planar plasma ion source generator 50 over its entire length. When a powder or a fluid that can be charged is introduced from the inlet 44 in the direction of the arrow 54, the fluid passage 4 on the outer periphery of 50 is introduced.
While passing through the plasma ion source 3, the plasma ion source removes and neutralizes static electricity, and is discharged to the outside from the outlet 45.

FIG. 8 is a planar plasma ion source generating apparatus used in the present invention, a perspective view of a modification of the one shown in FIG. 1, and FIG. 9 is a view of a portion thereof seen from behind.
Reference numeral 55 denotes a dielectric layer in the form of a rectangular plate, with a planar induction electrode 8 disposed on its back surface, and deep notches 56, 57, 58 formed at both peripheral edges 20, 21 at regular intervals. ,59 and 56',5
7', 58', and 59'. Reference numeral 60 denotes an insulating layer that covers the entire planar induction electrode, and is bonded to the back surface of the flat dielectric layer 50, leaving the notched portions at both ends uncovered. 61
is one linear corona discharge electrode, and the above notch 5
6→56'→57'→57→58→58'→59'→
The surface 62 of the flat dielectric layer 55 is sequentially fitted onto the dielectric layer 59, and then wrapped around the back and fixedly stretched.
Linear corona discharge electrodes 3, 4, 5, and 6 are arranged parallel to each other at equal intervals. Now terminal 1
When an AC high voltage is supplied between the linear corona discharge electrode 61 and the planar induction electrode from the conductors 4 and 15 through the conductive wires 16 and 17, a planar plasma ion source is formed on the surface 62. This device can be used in exactly the same way as the device shown in FIG.

A large number of planar plasma ion source generating devices shown in FIGS. 1 and 8 may be arranged along the inner wall of the cylindrical pipe body, or the devices shown in FIGS. 3 and 4 may be arranged in a cylindrical shape. It goes without saying that the novel pipe-type static eliminator according to the present invention can be constructed by arranging a plurality of static eliminators in a rectangular pipe main body.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an example of a planar plasma ion source generator used in the present invention, and FIG. 2 is a cross-sectional view thereof. FIG. 3 is a perspective view of another planar plasma ion source generator, and FIG. 4 is a side view of another planar plasma ion source generator. FIG. 5, FIG. 6, and FIG. 7 each show an embodiment of the pipe-type static eliminator according to the present invention. FIG. 8 is a perspective view of another planar plasma ion source generator, and FIG. 9 is a rear view of a portion thereof. The names of the main components in the diagram are as follows. 1, 18, 19, 29, 55... dielectric layer,
3,4,5,6,26,30,61... Corona discharge electrode, 8,33... Planar induction electrode, 12,60...
... Insulating layer for coating, 13 ... AC high voltage power supply, 1
4, 15...terminal, 16,17...conductor, 36,
46... Pipe main body, 39, 40, 47, 50...
Planar plasma ion source generator, 44...inlet;
45... Outlet, 48, 49... Flange, 43...
...Fluid passage.

Claims (1)

[Scope of Claims] 1. A pipe main body through which a charged object passes, and a plasma generating section is arranged in the pipe main body so as to be exposed to a flow path through which the charged object passes through the pipe main body. The planar plasma ion source generator includes an appropriate number of corona emitters attached to or adjacent to at least one planar dielectric layer on one side of the planar dielectric layer. An electrode is provided, a planar induction electrode is provided on the other side of the planar dielectric layer in contact with the dielectric layer so as to cover a portion facing the corona discharge electrode, and a high AC voltage is applied between both electrodes. Upon application, a creeping corona discharge is generated from the corona discharge electrode along the surface of the dielectric layer, thereby forming a planar plasma ion source. It has an AC high voltage power supply for applying an AC high voltage between the two, thereby forming a planar plasma ion source containing abundant positive and negative ions on the surface of the planar plasma ion source. A pipe-type static eliminator characterized by supplying ions having a polarity opposite to the electric charge of a charged object introduced into a flow path within the pipe main body to neutralize and eliminate static electricity. 2. The conduit-type static eliminator according to claim 1, wherein the planar plasma ion source generator is flat and is disposed along the side wall of the conduit main body. 3. The conduit type according to claims 1 and 2, characterized in that a covering insulating layer is provided in contact with the back surface of the planar dielectric so as to cover the entire planar induction electrode. Static eliminator. 4. The planar plasma ion source generator has a flat plate shape, and there are two dielectric layers sandwiching the planar induction electrode, and an appropriate number of corona discharge electrodes are attached to or adjacent to the outer surface of each layer. are provided, thereby forming a planar plasma ion source on both sides of the flat planar plasma ion source generating device, and inserting the planar plasma ion source into the fluid passage channel in the pipe main body. A pipe-type static eliminator according to claims 1 and 2, characterized in that an appropriate number of static eliminators are arranged in parallel with the pipe main body. 5. The planar plasma ion source generator has a cylindrical shape, and a corona discharge electrode is disposed adjacent to or adjacent to the outer surface of the cylindrical dielectric layer, and the planar induction electrode is in contact with the inner surface of the corona discharge electrode. is provided to form a planar plasma ion source on the external cylindrical surface of the cylindrical planar plasma ion source generating device, and to place the planar plasma ion source within the fluid passageway within the conduit body. A pipe-type static eliminator according to claim 1, characterized in that an appropriate number of static eliminators are arranged in parallel with the pipe main body. 6. The conduit type static eliminator according to claims 1 to 5, characterized in that the dielectric layer is an inorganic dielectric layer such as glass or ceramic. 7. Claims 1 to 6, characterized in that a linear corona discharge electrode such as a thin metal wire, a metal strip line, or a linear metal pattern formed by thick film printing is used as the corona discharge electrode. Pipeline static eliminator described in . 8. The conduit-type static eliminator according to claims 1 to 7, characterized in that the AC high-voltage power source is an AC high-voltage power source that generates a high-frequency AC high voltage with a frequency of 1 KHz or more. 9. The pipe-type static eliminator according to claims 1 to 8, characterized in that connection flanges are attached to both ends of the pipe main body. 10. The conduit type static eliminator according to claims 1 to 9, characterized in that the wall surface of the conduit main body has a structure that can be opened and closed to facilitate internal inspection. 11. The pipe-type static eliminator according to claims 1 to 10, characterized in that it is equipped with means for removing adhering dust on the corona discharge electrode.