JP2005001818A - Device for static-eliminating, supplying, and conveying charged powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a powder feeder capable of smoothly feeding easily-charged powder or charged powder and a pneumatic transportation device. <P>SOLUTION: A hopper 14 of the powder feeder comprises aeration means 16, 26, 30 equipped with a fine porous film 16 and applies aeration to powder in the hopper. An ionization device 38 such as a corona discharge device preliminarily ionizes air for the aeration. The ionized air is evenly blown to the powder in the hopper through the fine porous film 16 to remove electrical charge on the surface of the powder and eliminate static on the powder. The aeration makes the powder in the hopper involve air and an air layer is formed between the powder and an inner wall of the hopper, which restrains the power from being charged again. Secondary air or compressed air can be ionized as well in the pneumatic transportation device. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for supplying and pneumatically transporting a powder that is easily electrostatically charged.
[0002]
[Prior art]
In the industry, hoppers and pneumatic transport devices are used for storing and cutting out powders and transporting them to remote areas.
[0003]
[Problems to be solved by the invention]
Powders made of certain types of non-conductive materials aggregate with each other due to electrostatic charging, and electrostatically adhere to the inner walls of hoppers and air transport pipes, hindering smooth feeding. .
In particular, as the powder becomes finer (for example, on the order of a micrometer), the specific surface area becomes larger, so that charging tends to occur.
[0004]
An object of the present invention is to provide a powder supply device and a pneumatic transport device that can smoothly supply and transport this type of chargeable powder (powder that is easily charged or charged powder). .
[0005]
[Means for Solving the Problems]
In one aspect of the present invention, the present invention provides a powder supply device, the powder supply device comprising a hopper for containing and discharging the powder, and a microporous diaphragm, and the powder in the hopper An aeration means for aerating the body; and an ionization means for ionizing the air blown into the hopper by the aeration means, and the charged or easily charged powder in the hopper is ionized by the ionized air. It discharges while discharging.
[0006]
When ionized air is uniformly blown into the powder in the hopper through the microporous diaphragm, the ionized air neutralizes or removes the surface charge of the powder, so that the surface charge of the powder is reduced. It disappears and the powder is neutralized.
In addition, when aeration is performed through the microporous diaphragm, the particles in the hopper become estranged due to the air trapping the air, so that the chance that the powder particles come into contact with each other and collide and friction is reduced. Since an air layer is formed between the powder and the inner wall of the hopper, the powder is prevented from being newly charged, and the aggregation of the powder and the adhesion to the hopper are suppressed.
[0007]
In a preferred embodiment, a humidifier is further provided for humidifying the air ionized by the ionization means. This humidifier can be provided upstream or downstream of the blower of the aeration means.
If the air to be ionized in this way is humidified, the fine particles of water are charged when the air is ionized by the ionization means, so that the powder charge elimination efficiency is further improved.
[0008]
In another aspect, the present invention provides a pneumatic transport device, which includes a hopper for containing and discharging powder, and a microporous diaphragm for the powder in the hopper. An aeration means for performing aeration, an ionization means for ionizing the air blown into the hopper by the aeration means, and an air transport means for pneumatically transporting the powder discharged from the hopper to a remote place Yes.
[0009]
According to this pneumatic transport apparatus, since the powder transported by the pneumatic transport means is previously neutralized in the hopper, it can be transported smoothly without adhering to the pneumatic transport pipeline.
[0010]
In a preferred embodiment of the pneumatic transport device, the pneumatic transport means comprises a suction type pneumatic transport means with a suction nozzle, which is made of a conductive material and is grounded.
In this way, since the powder in the powder-air mixture transported by the air transport pipeline is further neutralized, transport is performed more smoothly.
[0011]
In a further preferred embodiment of the pneumatic transport device, the pneumatic transport means comprises a suction pneumatic transport means, the suction pneumatic transport means comprising secondary air supply means for supplying secondary air to the pneumatic transport line; And ionizing means for ionizing the secondary air supplied by the secondary air supply means.
If ionized air is used as the secondary air introduced into the suction-type pneumatic transport pipe in this way, the transported powder is further neutralized and transport is performed more smoothly.
[0012]
In another preferred embodiment of the pneumatic conveying device, the pneumatic conveying means comprises a pressurized pneumatic conveying means with a compressed air injection nozzle, which is an ionization for ionizing the air injected by the injection nozzle. Means.
In this embodiment, since ionized air is used as the pressure-feeding air, the powder sent through the air transportation pipeline is further neutralized, and the powder on the inner wall of the air transportation pipeline and the inner wall of the solid-gas separation device Prevents electrostatic adhesion of the body.
[0013]
In yet another preferred embodiment of the pneumatic conveying device, the pneumatic conveying means comprises a pressurized pneumatic conveying means with a compressed air actuated ejector, which ionizes the compressed air that is the drive source of the ejector. Ionizing means is provided.
Since ionized compressed air is used as a drive source for the ejector in this way, the powder sent through the pressure-feed pneumatic transport line is further neutralized and transported more smoothly, preventing electrostatic adhesion. The
The above-described features and effects of the present invention as well as other features and effects will be further clarified as the following examples are described.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
1 to 4 show an embodiment of the powder supply apparatus of the present invention.
Referring to these drawings, the powder supply apparatus 10 includes a support frame 12 formed of angle steel or the like, and a hopper 14 is mounted on the support frame 12. As can be clearly understood from FIG. 2, the hopper 14 includes an inner member 16 for aeration, an outer housing 18, and an upper housing 20.
[0015]
The inner member 16 for aeration of the contents of the hopper is formed of a microporous and self-supporting air-permeable diaphragm. The microporous diaphragm 16 is formed of an air permeable sheet such as high-density polyethylene, and preferably has pores with an average pore size of 10 to 20 μm. As shown in FIG. 2, the microporous diaphragm 16 has a flange 16A, a conical wall portion 16B, and a cylindrical outlet 16C.
[0016]
The outer housing 18 is formed of, for example, a stainless steel plate, and has an upper flange 18A, a conical wall portion 18B, a cylindrical portion 18C, and a lower flange 18D.
The upper housing 20 has a flange 20A and a cylindrical portion 20B.
[0017]
The inner member (microporous diaphragm) 16, the outer housing 18 and the upper housing 20 are integrally fastened by a plurality of bolts and nuts (one of which is indicated by reference numeral 22 in FIG. 2) passed through the flanges. Has been. As shown in FIG. 3, the flange 18 </ b> A of the outer housing 18 and the flange 20 </ b> A of the upper housing 20 are hermetically sealed by the packing 24.
[0018]
3 and 4, the conical wall portion 16B and the cylindrical portion 16C of the inner member 16 have a smaller radius than the conical wall portion 18B and the cylindrical portion 18C of the outer housing 18, respectively. An annular compressed air filling chamber 26 for filling the compressed air is formed between them.
In order to maintain a gap between the inner member 16 and the outer housing 18, a plurality of spacers 28 arranged at equal intervals in the circumferential direction are interposed therebetween.
[0019]
As can be clearly understood from FIG. 4, the lower end of the compressed air chamber 26 can be sealed with a gland packing 32 or the like. The gland packing 32 is compressed by a ring 34 welded to the inside of the outer housing 18 and a retainer 36 bolted to the lower flange 18D of the outer housing 18 to seal between the inner member 16 and the outer housing 18.
[0020]
The outer housing 18 is provided with a compressed air inlet 30 such as a nipple, and is connected to a blower or an air compressor 40 through a compressed air line to supply compressed air to the compressed air filling chamber 26 for aeration. It is supposed to be.
Between the blower 40 and the compressed air inlet 30, an air ionizer 38 such as a corona discharge device is provided to ionize the air sent to the compressed air filling chamber 26.
A humidifier 42 is provided upstream of the blower 40 so as to humidify the air sent to the ionizer 38.
[0021]
During the operation of the powder supply device 10, powder is put in the hopper 14 and the humidifier 42, the blower 40, and the air ionization device 38 are operated. The humidified and ionized compressed air for aeration enters the air filling chamber 26. From there, it passes through the microporous membrane 16 and flows out into the hopper.
Since the air permeable diaphragm 16 is microporous, there is no short path of air flow in the powder, and the powder in the hopper 14 is uniformly aerated by the ionized air.
[0022]
When aeration is performed with ionized air in this way, the ionized air neutralizes or carries away the surface charge of the powder, so that the surface charge of the already charged powder is lost and the powder is neutralized. The
At the same time, when aeration is performed through the microporous diaphragm 16, the particles in the hopper are estranged due to the air trapping, so that the chance that the powder particles come into contact with each other and collide and rub against each other is reduced. At the same time, since an air layer is formed between the powder and the inner wall of the hopper, it is possible to prevent the powder from being newly charged.
As a result, it is possible to suppress the powder from electrostatically adhering to the hopper and the particles from aggregating with each other. Therefore, the powder in the hopper is smoothly discharged from the discharge port 16C by its own weight without forming a bridge or forming a rat hole in the hopper.
[0023]
5 to 8 show different embodiments of the pneumatic transport apparatus incorporating the powder supply apparatus shown in FIG. In FIGS. 5 to 8, the same or equivalent components as those shown in FIGS. 1 to 4 are denoted by the same reference numerals, and redundant description is omitted.
Referring to FIG. 5, in this embodiment, the pneumatic transport device 50 is configured as a suction type pneumatic transport device (vacuum conveyor). The pneumatic transport device 50 includes a powder supply device 10 having an aeration hopper 14, an air ionization device 38, and a blower 40, and a suction nozzle 52 inserted into a discharge casing 51 connected to a lower discharge port 16 </ b> C of the hopper 14. And a pneumatic transport pipe 54 connected to the suction nozzle 52.
[0024]
The suction nozzle 52 is made of a conductive material such as aluminum or copper, and is grounded by a ground wire 56.
The pneumatic transport pipe 54 is connected to a conventional cyclone separator 58 with a built-in filter, and the cyclone separator 58 is mounted on the powder transport destination hopper 60. A blower 62 is connected to the cyclone separator 58, and negative pressure is applied to the cyclone separator 58 by operating the blower 62.
[0025]
In operation, the air ionization device 38 and the blower 40 are operated as described above, and the powder is discharged while discharging from the hopper 14 of the powder supply device 10.
When the suction transport blower 62 is operated, the powder discharged from the hopper 14 is sucked into the cyclone separator 58 through the suction nozzle 52 and the air transport pipe 54, and the solid-gas separated powder is separated from the cyclone. The powder is transferred from the container 58 to the powder transport destination hopper 60.
Since the suction nozzle 52 is formed of a conductive material and grounded, the powder discharged from the hopper 14 is further discharged by making electrical contact with the grounded suction nozzle 52. Therefore, the powder does not adhere to the inside of the pneumatic transport tube 54 or the cyclone separator 58 due to static electricity.
[0026]
A pneumatic transport device 50 shown in FIG. 5 was prototyped and tested. The suction nozzle 52 was made of aluminum. The powder in the hopper 14 was aerated while the corona discharge device 38 was operated, and the suction nozzle 52 was grounded and the powder from the hopper 14 was pneumatically transported to the cyclone separator 58. When observed with the naked eye, almost no powder adhered to the inner walls of the air transport tube 54 and the cyclone separator 58.
[0027]
FIG. 6 shows another embodiment of the suction type pneumatic transport apparatus. In FIG. 6, the same or equivalent components as those shown in FIGS. 1 to 4 and 5 are denoted by the same reference numerals, and redundant description is omitted.
Referring to FIG. 6, in this embodiment, ionized secondary air is supplied to a suction nozzle 52 connected to a lower discharge port of the hopper 14. For this reason, the suction nozzle 52 is provided with a secondary air control valve 64, and the inlet of the secondary air control valve 64 is connected to a secondary air ionizer 66. In order to compensate for the ventilation resistance of the secondary air ionizer 66, a blower 68 for pressurizing the secondary air may be provided as necessary.
[0028]
In the suction-type pneumatic transport apparatus shown in FIG. 6, since the secondary air introduced into the pneumatic transport pipe 54 is ionized by the secondary air ionizer 66, in addition to being neutralized in the hopper 14, the air The powder conveyed through the transport pipe 54 is more completely neutralized. Therefore, electrostatic adhesion of the powder is further suppressed.
[0029]
When the air transportation device shown in FIG. 6 was made as a trial and operated while the ionization devices 38 and 66 were operated, the adhesion of powder to the inside of the air transportation tube 54 and the cyclone separator 58 was hardly recognized.
[0030]
FIG. 7 shows a pumping pneumatic transport device. Constituent elements that are the same or equivalent to the constituent elements of the above-described embodiment are denoted by the same reference numerals.
Only the difference will be described with reference to FIG. 7, and this pressure-feed pneumatic transport device 70 includes an injection nozzle 72 connected to the air transport pipe 54, and the powder discharged from the hopper 14 is injected from the injection nozzle 72. The air flow is pumped to the cyclone separator 58 via the air transport pipe 54.
The injection nozzle 72 is connected to a blower or compressor 76 via an air ionizer 74.
[0031]
Also in this pressure-feed pneumatic transport device 70, the powder in the hopper is neutralized by aeration with ionized air.
Further, since the compressed air injected into the air transport pipe 54 is ionized in advance by the air ionization device 74, the powder is further neutralized in the air transport pipe 54 to the inner walls of the air transport pipe 54 and the cyclone separator 58. The electrostatic adhesion of the powder is effectively suppressed.
[0032]
FIG. 8 shows another embodiment of the pressure-feed type pneumatic transport apparatus. Constituent elements that are the same as or equivalent to the constituent elements of the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.
Referring to FIG. 8, this transport device 70 includes an ejector 78 connected to a hopper discharge housing 51, and the powder discharged from the hopper 14 is pumped to a cyclone separator 58 via an air transport pipe 54. It is supposed to be.
[0033]
FIG. 9 shows an example of the configuration of the ejector 78. The ejector 78 is of a conventional type, and when compressed air is injected from the compressed air inlet 80, a high-speed air flow toward the discharge port 82 is generated by the Coanda effect, and the inlet air is attracted to the suction port 84. It has become. As a result, the powder discharged from the hopper 14 is pumped to the cyclone separator 58 via the air transport pipe 54.
The compressed air inlet 80 of the ejector 78 is connected to an air ionizer 86 and a blower 88 so that compressed air as a drive source of the ejector 78 is ionized. A discharge port 82 of the ejector 78 is connected to the pneumatic transport pipe 54.
[0034]
Also in the pressure-feed type pneumatic transport device 70 of FIG. 8, the powder in the hopper is still discharged by aeration with ionized air.
In addition, since the compressed air as the drive source of the ejector 78 is ionized in advance by the air ionization device 86, the powder is further neutralized while being sent through the air transport pipe 54 to the air transport pipe 54 and the cyclone separator 58. The electrostatic adhesion of the powder is also effectively suppressed.
[0035]
【The invention's effect】
According to the present invention, the powder in the hopper is neutralized by aeration with ionized air, and the powder is prevented from agglomerating and adhering to the hopper, so that the powder is smoothly discharged from the hopper. .
In the pneumatic transportation device of the present invention, when using secondary air for suction pneumatic transportation or ionized air as driving air for pressure pneumatic transportation, static elimination is further performed in the pneumatic transportation pipeline, It is possible to prevent static electricity from adhering to the inner wall of the air transport pipe, the vacuum conveyor, the cyclone separator, and the inner wall of the destination container.
Similarly, when the suction nozzle of the suction type air transport device is formed of a conductive material and grounded, it is possible to prevent electrostatic adhesion.
[Brief description of the drawings]
FIG. 1 is a schematic view of a powder supply apparatus of the present invention.
FIG. 2 is an exploded perspective view of a hopper of the powder supply apparatus shown in FIG.
FIG. 3 is an enlarged cross-sectional view taken along line III-III in FIG.
4 is an enlarged sectional view taken along line IV-IV in FIG. 2;
FIG. 5 is a schematic view of the suction type pneumatic transport apparatus of the present invention.
FIG. 6 is a schematic view of another embodiment of the suction type pneumatic transport apparatus of the present invention.
FIG. 7 is a schematic view of the pressure-feed type pneumatic transportation device of the present invention.
FIG. 8 is a schematic view of another embodiment of the pressure-feed type pneumatic transport apparatus of the present invention.
9 is a cross-sectional view of the ejector shown in FIG.
[Explanation of symbols]
10: Powder supply device 14: Hopper 16: Microporous membrane 16/26/30: Aeration means 38: Ionization means 42: Humidifier 52/54: Air transport means 52: Suction nozzle 64: Secondary air supply means 66 : Secondary air ionizer 72: compressed air injection nozzle 76: compressed air ionization means 78: ejector 86: compressed air ionization means

Claims (7)

A hopper for containing and discharging powder, an aeration means for providing aeration to the powder in the hopper with a microporous diaphragm, and ionization for ionizing the air blown into the hopper by the aeration means And a powder supply device for discharging the charged or easily charged powder in the hopper while removing electricity with ionized air. The powder supply apparatus according to claim 1, further comprising a humidifier for humidifying the air ionized by the ionization means. A hopper for containing and discharging powder, an aeration means for providing aeration to the powder in the hopper with a microporous diaphragm, and ionization for ionizing the air blown into the hopper by the aeration means And a pneumatic transporting device for pneumatically transporting the powder discharged from the hopper to a remote place. 4. The pneumatic transport apparatus according to claim 3, wherein the pneumatic transport means includes a suction type pneumatic transport means having a suction nozzle, and the suction nozzle is formed of a conductive material and is grounded. The pneumatic transport means comprises a suction type pneumatic transport means, and the suction type pneumatic transport means is supplied by a secondary air supply means for supplying secondary air to an air transport pipeline and the secondary air supply means. An air transport device according to claim 3, further comprising ionization means for ionizing the secondary air. The pneumatic transport means comprises a pressure-feed type pneumatic transport means provided with a compressed air injection nozzle, and the pressure-feed type pneumatic transport means comprises an ionization means for ionizing the air jetted by the jet nozzle. A pneumatic transport device according to claim 3. The pneumatic transport means comprises a pressure-feed type pneumatic transport means having a compressed air-operated ejector, and the pressure-feed type pneumatic transport means comprises an ionization means for ionizing compressed air as a drive source of the ejector. Pneumatic transport device according to claim 3 characterized by the above.

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