JP2003236463A - Powder transporting method, powder fluidizing route, powder transporting means and powder container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly and reliably carry out fluidization transportation, transfer, supply, recovery, and the like, of a powder by decreasing adhesion of the powder to a guide face of a fluidizing route and a transportation face of a transporting means. <P>SOLUTION: A coating layer of a graphite fine powder is formed in the powder guide face of the powder fluidizing route to which the powder is brought into contact, the transportation face of the powder transporting means, and an inner face of a powder container to fluidize and transport the powder, transfer the powder by the transporting means, and take the powder in and out. As shown in the Figure, a coating layer 2 of a fine powder 2a of graphite is formed on a base plate 2 while being fixed with an anchor layer of an adhesive. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has a particle size of 200 μm.
TECHNICAL FIELD The present invention relates to a powder transport method for transporting powder of about 10 μm to 10 μm without adhering to the powder guide surface of a powder flow path or a transport surface of a transport means, and a flow path, transport means and container used for powder transport. .

[0002]

2. Description of the Related Art Powder (fine particles) easily adheres to a contact partner, and particularly in fluidized transportation, even if the inclination angle of the powder guide surface is increased or vibration is applied, the transportation and recovery cannot be performed well. Sometimes.

It is generally considered that the cause of adhesion of fine particles to a contact object is static electricity and humidity.

The humidity can be easily controlled by dehumidifying and humidifying, but it is very difficult to prevent the generation of static electricity, and it is considered impossible to completely remove static electricity.

Generally, in the direction of suppressing static electricity rather than preventing it, a method of releasing electric charges and a slow electric method of neutralizing the electric charges of the charged body by giving electric charges of the opposite sign to the electric charges of the charged body are considered. Is.

[0006] As an electrostatic material for releasing charges, a method of making the material conductive is usually used, and a polymer material or the like is manufactured by mixing a conductive substance.

There is also a method of making the surface conductive with a metal. The metal film on the surface is formed by chemical plating, vacuum deposition, sputtering, or the like and has extremely good conductivity, and therefore has sufficient characteristics to leak static electricity.

There is also a conductive paint in which a fine powder of a conductive substance is mixed in the paint. The paint film is inferior in conductivity to the metal film, but there is no problem in leaking electric charges.

In addition, as the antistatic agent, a surfactant is generally used in order to accelerate the leakage of charges.

[0010]

In the transportation of powder, adhesion occurs even if the above-mentioned static electricity suppression measures are taken. Adhesion is particularly remarkable for powders having a particle size of 200 μm or less.

For this reason, the powder is not often conveyed by the method of allowing the guide surface to flow naturally.

The present applicant has developed a defect sorter for removing defective products whose shape has been lost from spherical particles of metal or the like produced by the atomization method by utilizing the difference in rolling condition and rolling speed of the particles. However, since fine powder adheres to the guide surface, it was difficult to include it in the selection target.

Further, in the case of carrying by a carrying means such as a belt conveyor or a screw feeder, it is necessary to frequently clean and remove the powder adhering to the carrying surface.

Cleaning and removal of the powder adhering to the inner surface of the hopper and the container for collection and storage are indispensable, and the wasteful work increases.

Therefore, an object of the present invention is to effectively reduce the adhesion of powder to the guide surface, the conveying surface, and the inner surface of the container.

[0016]

In order to solve the above-mentioned problems, in the present invention, a coating layer formed of fine graphite powder is provided on the powder guide surface of the flow path, and the powder is fluidized and conveyed. A powder carrying method and a powder carrying method in which a coating layer formed of fine graphite powder is provided on a carrying surface of a powder carrying means, and the powder is carried by the carrying means.

Further, a powder flow path having a coating layer formed of fine graphite powder on a powder guide surface, a powder conveying means having a coating layer formed of fine graphite powder on a conveying surface, and graphite Also provided is a powder container having a coating layer formed of the above fine powder on its inner surface.

The fine graphite powder forming the coating layer is preferably fixed by providing an anchor layer formed of an adhesive or the like. The anchor layer is covered with graphite to expose the graphite powder on the surface.

The graphite powder preferably has a smaller particle size than the powder to be conveyed. Particle size is from 200 μm
When the powder having a particle size of about 10 μm was conveyed, the particle size of the graphite powder was particularly preferably about 30 μm to 3 μm.

In addition, if a container for dropping and dropping powder is provided with a layer of urethane rubber or the like acting as a cushion layer on the inner surface and a coating layer made of fine graphite powder is provided on the surface of the cushion layer. preferable.

[0021]

[Function] It is thought that the cause of the powder adhering to the contact object is mainly the static electricity, and the gradual electric method was applied to the flow-conveying method in which the powder was supplied onto the inclined plate and allowed to flow naturally. Since the particles are fine, it is difficult to balance the ions with the charged particles, and since the ions do not enter the contact area of the particles, the charge at the contact area cannot escape, and the powder is deposited on the inclined plate. It stayed and did not flow well.

Next, an attempt was made to see if the powder flowed without adhering to it by using an inclined plate provided with an electrically conductive polymer material or an electrically conductive film, but this also did not give very good results. .

In view of these experimental results, the inventor has tried various methods other than removing the influence of static electricity and found that a coating layer formed of fine graphite powder is effective as a solution to the problem. It was

If the surface roughness of the graphite coating layer provided on the powder guide surface of the flow path is sufficiently smaller than the particle size of the powder to be conveyed, the flow of the powder in the flow conveying method will be dramatically increased. Get better.

Graphite has a small friction coefficient. In addition to this, the surface of the coating layer formed of fine powder is appropriately roughened, which reduces the contact area with the powder. Further, it is speculated that the flow of the powder may be improved because graphite has conductivity and the adsorption force due to static electricity is weakened.

Even when powder is conveyed by a conveying means such as a belt conveyor or a screw feeder, the graphite coating layer reduces the adhesion of the powder to the conveying surface provided with the graphite coating layer.

The same applies to the powder container, and the graphite coating layer serves to reduce the possibility that powder adheres to and remains on the inner surface of the container.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows an example of the powder flow path of the present invention. In the figure, reference numeral 1 is a base plate that constitutes a slanting plate for flow conveyance, a trough, a shooter,
A coating layer 2 formed of graphite fine powder 2a is provided on the surface of the base plate 1 which forms a powder guide surface. 3 is an anchor layer for fixing the fine powder 2a on the base plate 1. Depending on the condition of the surface of the base plate 2 and the material of the surface layer, fine powder may be retained without the anchor layer, but it is preferable to provide the anchor layer 3 for reliable fixation and retention.

Here, the anchor layer 3 is formed of an adhesive. The adhesive may be either a solvent type adhesive or a cyanoacrylate (so-called instant adhesive). As the solvent-type adhesives, synthetic rubber-based adhesives, nitrile rubber-based adhesives, epoxy-based adhesives and the like were tested, but there was no shortage. The mixing ratio of the adhesive and the organic solvent is preferably about 1: 5 to 1:20. In the case of coating a base plate made of urethane rubber or the like, a small amount of adhesive is required, and for a base plate made of a hard material such as glass, it is preferable that the amount of adhesive is increased because a stronger adhesive force can be obtained.

Fine graphite powder 2a and an adhesive diluted with an organic solvent are mixed and spread evenly on the surface of the base plate 1. At this time, if a spray is used, efficient coating can be performed.

Immediately after coating, the fine powder 2a is buried in an organic solvent mixed with an adhesive. However, when the organic solvent vaporizes, the adhesive remains and sinks to form an anchor layer 3 as shown in the figure. The fine powder 2a is bonded and fixed.

Solder balls with a particle size of 100 μm (hereinafter BG
In the experiment in which the ball A is referred to as a rolling transport (the rolling transport is also regarded as a fluid transport in the present invention), the same result is obtained regardless of the kind of the adhesive. Therefore, the adhesive is not present on the fine powder 2a. It seems that all the graphite is exposed on the surface.

The organic solvent used to dilute the adhesive was better with lacquer thinner containing toluene than paint thinner without toluene. This seems to be related to the solubility and volatility of the adhesive.

The transport device of the present invention is provided with a coating layer similar to that shown in FIG. 1 on the transport surface and on the inner surface of the powder container.

The test results will be described below. As the graphite fine powder, rod-shaped graphite was scraped off with a file, and an average particle size of about 30 μm to 3 μm was prepared.

As the adhesive, four kinds of styrene-butadiene rubber-containing adhesive, cyanoacrylate adhesive, chloroprene rubber-containing adhesive and polyurethane rubber-containing vinyl chloride resin adhesive were prepared, and a lacquer thinner for dilution was also prepared. .

Further, the following were prepared as a base plate. Urethane rubber coating plate Soda glass plate Stainless steel plate Glass plate with conductive chrome film by sputtering Polyurethane impregnated resin belt

A graphite coating layer is formed on a part of the surface of each of these base plates by using the prepared adhesive and graphite fine powder, and the portion where the coating layer is provided (referred to as A) and the coating are formed. For the part without a layer (this is B), the BG of 100 μm described above
The flow conditions of ball A were compared.

First, the urethane rubber coating plate is placed horizontally, and a large number of BGA spheres are evenly placed on the parts A and B. After that, the urethane rubber coating plate is placed in the tray so that the parts A and B are substantially vertical. I leaned until I stood up. As a result, almost all of the BGA spheres on the site A fell into the tray. On the other hand, most of the BGA spheres on the site B remained attached and remained on the base plate.

Next, with the soda glass plate horizontal, BGA balls were placed on the parts A and B, and then the soda glass plate was tilted in the tray until the inclination angle was 45 degrees. As a result, the amount of BGA spheres remaining on the site A was extremely small, which was extremely smaller than the amount remaining on the site B.

The stainless steel plate (1) has conductivity and easily discharges static electricity, but a large number of BGA spheres remained and remained on the site B in the same 45 ° tilt test as the soda glass plate. On the other hand, the BGA spheres on the site A flowed down and hardly remained.

With respect to this stainless steel plate, the flow of BGA spheres when the antistatic agent was applied was also examined. As a result, even if the antistatic agent was applied, the flow of the BGA spheres was poor, and even if the stainless steel plate was tilted almost vertically, the adhered BGA spheres remained without flowing, as in the uncoated portion B.

The glass plate provided with the chrome film of
When a BGA ball was placed on B and gradually tilted to an angle of about 15 degrees in the tray, some BGA balls on part A stopped flowing in the middle, while on the part B Most of the BGA spheres remained in their original position.

With respect to the polyurethane-impregnated resin belt, the adhesion amount of BGA balls when the belt was tilted was significantly smaller in the region A than in the region B. If a belt without a graphite coating is used on a low speed belt conveyor, it is easy for powder to remain on the transport surface even after the belt turns at the forward end and the transport surface faces downward. Can be guessed. With the graphite coating layer, the powder is better separated from the transport surface and the transport surface does not need to be cleaned frequently.

Next, the powders selected by the defect sorter are dropped on the inclined guide plate, collected by the guide plate, and poured into a container placed in the lower front of the plate. A coating layer of urethane rubber that acts as a layer was provided, and a coating layer made of fine graphite powder was provided on top of that, and a BGA sphere recovery test was conducted. As the urethane rubber is soft, it does not damage the BGA sphere, and The graphite coating layer facilitated and speeded up the collection of BGA spheres and greatly simplified container cleaning.

The graphite coating layer 2
Is also effective when provided on the inner surface of a powder supply hopper, the inner surface of a duct or tube for powder transfer, the conveying surface of a screw feeder, the inner surface of a container used for collecting and storing powder, and the like.

It is also effective to provide the coating layer 2 on a part of the powder flow path or the transfer surface of the transfer means (only the part where the powder adheres).

[0048]

As described above, according to the present invention, a coating layer formed of fine graphite powder is provided on the powder guide surface of the flow transfer path, the transfer surface of the transfer means, and the inner surface of the powder container for fluid transfer. In order to prevent powder from adhering and accumulating during transportation and transportation, for example, in a defective sorter such as a BGA ball or a collecting device, the flow of powder is improved, and stable sorting and smoothing are possible without adding vibration. It can be collected.

Further, it becomes easy to clean the flow path formed by the inclined plate, the trough, the tube, the transport surface of the transport means such as the belt conveyor and the screw feeder, and the inner surface of the hopper, the powder container, etc. You can also reduce the time, labor and time.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an example of a flow path of the present invention.

[Explanation of symbols]

1 base plate 2 coating layers 2a Graphite fine powder 3 anchor layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B65G 15/30 B65G 15/30 Z 4D075 43/00 43/00 M 65/30 65/30 BF term ( Reference) 3E062 AB08 JA01 JA07 JB23 JD07 3F011 AA07 BA02 3F024 AA06 BA04 CA04 CB01 CB07 3F027 AA02 AA05 AA09 CA07 DA19 3F075 AA08 BA01 BB01 DA01 EB23EB15 EB15 EB15 EB15 EB15 EB15 DB20 DB15 DB12 DB15 DB23 DB12 DB15 DB23 DB12 DB15 DB23 DB12 DB15 DB12 DB15 DB23 DB12 DB15 DB12 DB15 DB23 DB16 DB23

Claims (5)

[Claims] 1. A powder conveying method in which a coating layer made of fine graphite powder is provided on a powder guide surface of a flow path to flow and convey the powder. 2. A powder carrying method in which a coating layer made of fine graphite powder is provided on the carrying surface of the powder carrying means, and the powder is carried by the carrying means. 3. A powder flow path in which a coating layer formed of fine graphite powder is provided on the powder guide surface. 4. A powder carrying means having a carrying surface provided with a coating layer formed of fine graphite powder. 5. A powder container having a coating layer formed of fine graphite powder on its inner surface.