JP4069234B2 - Method for filling powder into container - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for filling a container with a powder that has a small bulk density and easily causes flushing as densely as possible.
[0002]
[Prior art]
Certain powders with low bulk density and weak interparticle adhesion may exhibit fluidity like water when the air content increases upon aeration. Such a phenomenon is called “flushing” in the field of powder technology.
There are various flushing powders (powder that easily causes flushing) in the industry. For example, toner of an electrostatic copying machine has a considerable flushing property. This is because the toner particles are subjected to surface modification in order to improve the fluidity in the copying machine.
Also, the dry process amorphous silica powder added to the plastic injection molding material is likely to be flushed. In addition, alumina fine powder, slaked lime fine powder, pulverized coal, and the like also cause flushing.
[0003]
[Problems to be solved by the invention]
When this type of flushing powder is aerated for some reason and causes flushing, it flows like water, making it very difficult to handle.
For example, powder such as toner of an electrostatic copying machine must be transported to another place by being put in a transport container when manufactured at the manufacturing plant. Since the suction is performed by pneumatic transportation, the powder inevitably undergoes aeration when filling the transport container. As a result, when the powder is transferred from the transport container or the like to the final container, the powder causes flushing and flows like water, which makes measurement and transfer to the final container very difficult.
In addition, when aeration is applied to the transport container, the bulk density is reduced, so that the efficiency of filling the transport container is deteriorated, a large transport container is required, and the transport efficiency is lowered.
[0004]
An object of the present invention is to provide a method for filling a container with a flushing powder having a small bulk density as compactly as possible without causing flushing.
Another object of the present invention is to provide a filling method capable of filling a powder having a small bulk density into a container as small as possible.
[0005]
[Means for Solving the Problems]
In the present invention, when the powder contained in the first container is pneumatically transported to the second container by vacuum suction and filled into the second container, (1) one end of the air transport pipe is placed in the first container. Positioning in the powder and hermetically connecting the other end of the pneumatic transport pipe to the second container; and (2) a first level negative pressure in the second container with the pneumatic transport pipe conducting. (3) shutting off the air transport pipe and moving the air by sucking the powder in the first container to the second container by suction through the air transport pipe by applying (low vacuum) A second level of negative pressure (high vacuum) stronger than the first level of negative pressure is applied to the second container in a state in which the inflow of air into the second container through the tube is blocked. And a step of degassing the powder in the container.
[0006]
Thus, in the method of the present invention, in the deaeration step, the air transport pipe is shut off to stop air transport, and the second container is vacuum-sucked in a state in which the inflow of air to the second container is blocked. A high vacuum is established in the second container that cannot be achieved during pneumatic transportation.
As a result, the powder in the second container is effectively degassed and filled into the second container more compactly and densely.
In this way, since the powder is packed compactly and densely in the second container, the powder does not cause flushing when transferred from the second container to another container and can be handled easily. Can do.
In addition, since the powder is filled more densely in the second container, the second container can be reduced in size.
[0007]
Preferably, the air transporting step is carried out under a negative pressure stronger than about -10 kPa on average, more preferably under a negative pressure of about -30-60 kPa on average, and the deaeration step is carried out under a negative pressure stronger than that.
In a preferred embodiment, the pneumatic transport and degassing steps are repeated until the second container is filled with the desired amount of powder.
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.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The attached drawings show an application example of the method of the present invention. Referring to the drawings, the method of the present invention can be implemented to pneumatically transport powder 12 contained in a first container 10 to a second container 14 and fill the second container.
As a non-limiting example, the first container 10 is a container (for example, a container for storing manufactured toner) disposed in a powder preparation manufacturing plant (for example, a toner manufacturing plant), and the second container 14 is a powder. It may be a body transport container (for example, a container for transporting toner manufactured in a manufacturing plant to another place). As will be described later, the powder transport container 14 can be replaced with a hopper or other container.
[0009]
The method of the present invention is carried out using a vacuum conveyor device 16. The vacuum conveyor device 16 includes a cylindrical main body 20 whose upper portion is closed by a circular top plate 18, and an air transport pipe 22 passing through the main body 20 is fixed by welding or the like.
One end of the air transport tube 22 is opened inside the main body 20, and a suction nozzle 26 can be connected to the other end via a vacuum hose 24.
[0010]
An opening / closing valve device 28 is attached to the inner end of the main body of the air transport pipe 22 so as to open and close the inner end of the air transport pipe 22. The on-off valve device 28 includes a bracket 30 fixed to the air transport pipe 22 by welding or bolting, a compressed air drive type rotary actuator 32 fixed to the bracket, and a swing fixed to the output shaft of the actuator 32. A movable arm 34 and a movable valve body 36 attached to the swing arm 34 can be used.
The rotary actuator 32 is of a 90-degree swing type, and the inner end of the air transport tube 22 can be fully opened or fully closed by the movable valve body 36 by swinging the swing arm 34 by about 90 degrees.
[0011]
The top plate 18 of the vacuum conveyor device 16 is provided with a conventional vacuum pump 38, which sucks air inside the main body 20 through an outlet opening (not shown) of the top plate 18 and vacuums the inside of the main body. Can be made to act. As the vacuum pump 38, a conventional multistage ring blower, a roots blower, or an ejector type vacuum pump can be used.
A filter 40 is mounted on the upstream side of the vacuum pump 38 and below the top plate 18 to remove dust from the air sucked into the vacuum pump 38.
Although not shown, a conventional air pulse generator for backwashing the filter 40 is attached to the top plate 18, and the filter 40 can be backwashed by periodically emitting air pulses toward the inside of the filter 40. it can.
[0012]
When filling the toner 12 in the first container 10 into the toner transport container 14, the main body 20 of the vacuum conveyor device 16 is placed on the toner transport container 14, and the both are airtight using the seal ring 42. Connecting.
The tip of the suction nozzle 26 is charged and positioned in the toner 12 in the first container 10, and the vacuum pump 38 is operated with the on-off valve device 28 fully opened. Thereby, the toner 12 in the first container 10 is vacuum-sucked together with air toward the inside of the main body 20 of the vacuum conveyor device 16 through the vacuum hose 24 and the air transport pipe 22. The exhaust of the vacuum pump 38 is released to the atmosphere.
The toner 12 pneumatically transported into the main body 20 stalls and falls, and accumulates in the second container 14 as shown.
[0013]
After pneumatic transportation for a predetermined time, the rotary actuator 32 is switched to fully close the on-off valve device 28 and the inner end of the pneumatic transportation pipe 22 is closed. As a result, air transportation of the toner from the first container 10 to the second container 14 is stopped, and at the same time, the inflow of air into the second container 14 through the air transportation pipe 22 is blocked.
However, since the operation of the vacuum pump 38 continues, the vacuum pump 38 continues to exhaust the air inside the main body 20 of the vacuum conveyor device 16 and the second container 14. As a result, a high degree of vacuum is gradually established inside the main body 20 and the second container 14.
The toner deposited on the bottom of the second container 14 is gradually degassed by the action of high vacuum, tightening, and increasing the bulk density.
[0014]
After performing the deaeration process for a predetermined time, the rotary actuator 32 is switched again to fully open the on-off valve device 28, and air transportation is resumed.
In this way, the air transportation process and the deaeration process are repeated until the second container 14 is filled with a desired amount of toner. As a result, the second container 14 is filled with toner in a compact and compact state.
When the filling of the first second container 14 is completed, the filled second container 14 can be removed from the vacuum conveyor device 16 and a new second container can be connected.
[0015]
Although not shown in the drawings, as another embodiment, a conventional hopper can be used as the second container instead of the powder transport container 14, and the vacuum conveyor device 16 is placed on the hopper. By airtight connection, the powder can be pneumatically transported from the first container 10 to the hopper. After pneumatic transportation, the powder can be deaerated by closing the on-off valve device 28 and applying a high vacuum as described above, and the powder can be compactly filled in the hopper.
[0016]
【The invention's effect】
As described above, according to the present invention, the pneumatic transportation of the powder is stopped, and the operation of the vacuum pump 38 is continued with the on-off valve 28 being fully closed. Since the vacuum is established, the powder filled in the second container 14 is forcedly and positively subjected to effective deaeration action and tightened, and the bulk density increases. Therefore, the powder is prevented from flushing during the subsequent handling, and the handling and weighing of the powder becomes easy.
[Brief description of the drawings]
FIG. 1 is a partially cutaway front view showing a state where powder is filled into a container by the method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10: 1st container 12: Powder 14: 2nd container 16: Vacuum conveyor apparatus 22, 24, 26: Air conveyance pipe line 28: On-off valve apparatus 38: Vacuum pump

Claims (4)

When the powder contained in the first container is pneumatically transported to the second container which can be located away from the first container by vacuum suction and filled into the second container,
Positioning one end of the air transport conduit in the powder in the first container and hermetically connecting the other end of the air transport conduit to the second container;
The first level of negative pressure is applied to the second container by a negative pressure source in a state where the air transport pipe is conducted, whereby the powder in the first container is secondly sucked through the air transport pipe. A process of pneumatically transporting the container;
A second level higher than the first level of negative pressure by the negative pressure source in a state where the air transport line is shut off and the inflow of air into the second container through the air transport line is blocked. Degassing the powder in the second container by applying a negative pressure to the second container;
A powder filling method comprising:   2. The powder filling method according to claim 1, wherein the air transporting step is performed under a negative pressure stronger than an average of about −10 kPa, and the degassing step is performed under a negative pressure stronger than that.   3. The powder filling method according to claim 2, wherein the air transportation step is performed under a negative pressure of about -30 to 60 kPa on average, and the deaeration step is performed under a stronger negative pressure.   4. The powder filling method according to claim 1, wherein the second container is filled with powder by repeating the air transporting step and the deaeration step.

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