JP4418636B2 - Powder degassing method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for degassing and tightening airy and fluffy powder (in this specification, powder includes short fibers).
[0002]
[Prior art]
Certain powders with low interparticle force (van der Waals force), such as amorphous silica powder added as a reinforcing filler to plastic injection molding materials and alumina fine powder, are in the manufacturing stage and pneumatic transport. When subjected to aeration at the stage or handling stage, it becomes a fluffy state containing air.
[0003]
[Problems to be solved by the invention]
When the powder contains air and is bulky in this way, the filling efficiency deteriorates when packing into a bag or a container, and a large bag or container is required, increasing the logistics cost.
Further, when the reinforcing silica powder or the like is cut out from the hopper to the extruder so as to add the reinforcing filler to the main material of the injection molding, it is easy to form a bridge in the hopper if the powder contains air and is fluffy.
On the other hand, in some cases, air-containing powder may exhibit water-like fluidity (flushing phenomenon), which also makes it difficult to handle the powder.
[0004]
Therefore, the present inventor first transported the powder to the destination container using a vacuum conveyor, and then vacuumed the destination container after fully closing the inlet of the vacuum conveyor, It has been proposed to forcibly degas the powder in the container (Japanese Patent Laid-Open No. 2001-287701).
[0005]
An object of the present invention is to provide a powder degassing method and apparatus which are improved by the above-described method and have a superior degassing effect.
[0006]
[Means for Solving the Problems]
The present invention is characterized in that the powder is degassed by dropping it in a vacuum (negative pressure) atmosphere while dispersing the powder.
In this way, if the powder is deaerated while being dropped in a vacuum while being dispersed, the air between the particles is easily taken away, so that the powder is quickly degassed and tightened.
According to the present invention, compared with the case of deaeration in a stationary state, it was possible to deaerate more than 20-30% in a shorter time and in volume shrinkage.
[0007]
In another aspect, the present invention provides a powder degassing apparatus for carrying out the degassing method, the apparatus comprising: at least three modular hopper units connected one above the other in an airtight manner Each hopper unit includes a hopper having a powder discharge port, a damper mechanism for opening and closing the powder discharge port of the hopper, and a deaeration chamber in cooperation with the hopper of the lower hopper unit below the hopper And at least the uppermost and middle hopper units are provided with means for applying a negative pressure to the deaeration chamber at a predetermined time.
This device opens the damper of the uppermost hopper unit, loads the powder into the hopper of the middle hopper unit, closes the damper of the uppermost hopper unit, and loads it into the deaeration chambers of the uppermost and middle hopper units. After the pressure is applied, by opening the damper of the middle hopper unit, by dropping the powder in a dispersed state across the deaeration chamber under the negative pressure of the middle hopper unit to the hopper of the lowermost hopper unit It is characterized by degassing the powder.
[0008]
In a preferred embodiment, the apparatus further applies a negative pressure to a fourth hopper unit connected below the third-stage hopper unit and a deaeration chamber of the third-stage hopper unit at a predetermined time. For further degassing by dropping the powder in a dispersed state across the degassing chamber under the negative pressure of the third hopper unit to the hopper of the fourth hopper unit. Yes.
[0009]
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.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the degassing method and apparatus of the present invention will be described with reference to the accompanying drawings showing non-limiting embodiments. FIG. 1 shows a first embodiment of the present invention.
Referring to FIG. 1, the deaeration device 10 includes three hopper units 12, 14, and 16 connected up and down. In order to reduce the cost by sharing the components, these hopper units 12, 14, and 16 can be configured in the form of a common and compatible module. These hopper units 12, 14, and 16 are connected in an airtight and separable manner by a plurality of buckle devices 18 and other connecting means through appropriate packing (not shown).
In order to increase the powder capacity of the upper hopper unit 12, it is preferable to connect the silo 20 on the first stage unit 12.
[0011]
Since the three hopper units 12, 14, and 16 can be configured identically, only the upper hopper unit 12 will be described.
Referring to FIG. 2, in the illustrated embodiment, the hopper unit 12 includes a flanged cylindrical body 22 formed of stainless steel, a flanged hopper 24 formed of stainless steel, and the like. And a damper mechanism 30 having a flap valve 28 for opening and closing the powder discharge port 26.
A deaeration chamber 32 that can be sealed in cooperation with the hopper of the lower hopper unit 14 is defined inside the main body 22 below the hopper 24.
A pressure introducing pipe 34 opened to the deaeration chamber 32 is attached to the side wall of the main body 22 so as to apply a negative pressure to the deaeration chamber 32.
[0012]
2 and 3, in the illustrated non-limiting example, the damper mechanism 30 includes a flap valve 28 and a swing arm 38 with a roller 36 for swinging the flap valve 28 upward, For example, a 90 degree swing vane type aerodynamic actuator 40 for swinging the swing arm 38 is provided.
[0013]
The flap valve 28 is attached to, for example, a pair of left and right swing arms 42, and the end portions of these swing arms 42 are pivotally attached to a mounting bracket 44 fixed to the hopper 24 by welding or the like via a pivot 46. Can do.
As can be seen from FIG. 2, an elastomeric lip seal ring 48 is attached to the lower edge of the hopper 24 so as to seal between the lower edge of the hopper 24 and the flap valve 28. In order to ensure that the seal ring 48 is sealed even if the seal ring 48 is worn or worn, the pivot shaft 46 of the swing arm is provided in a long hole (not shown) of the mounting bracket so that it can move slightly in the vertical direction. It is installed.
The swing arm 38 with the roller 36 can be pivotally attached to the mounting bracket 44 via the output shaft 50 of the actuator 40.
[0014]
Referring to FIG. 1, the pneumatic actuator 40 of the damper mechanism 30 of the hopper unit 12 can be controlled by the control device 54 via the air signal line 52.
Similarly, the pneumatic actuators of the damper mechanisms 56 and 58 of the middle and lower hopper units 14 and 16 are controlled by the control device 54 via the air signal lines 60 and 62, respectively.
[0015]
Still referring to FIG. 1, the pressure inlet tube 34 of the hopper unit 12 may be connected to a vacuum source 66 by a conduit 64. As the vacuum source 66, a blower such as a turbo blower, a roots blower or a multistage ring blower, an ejector type vacuum pump, or any other type of vacuum pump can be used.
The conduit 64 is provided with, for example, a pneumatic shut-off valve 68 controlled by the control device 54 via an air signal line 70, and the vacuum or negative pressure of the vacuum source 66 is reduced by opening the shut-off valve 68. The deaeration chamber 32 is applied.
Similarly, the pressure introducing pipe 72 of the middle hopper unit 14 can be connected to the vacuum source 66 by a conduit 74. The pneumatic shut-off valve 76 provided in the conduit 74 is controlled by the control device 54 via the air signal line 78, and when the shut-off valve 76 is opened, negative pressure is applied to the deaeration chamber 80 of the hopper unit 14.
[0016]
Preferably, the pressure introduction pipe 82 of the lower hopper unit 16 and the pressure introduction pipe 72 of the middle hopper unit 14 include an air operated shut-off valve 84 controlled by the control device 54 via an air signal line 88. Connect by bypass conduit 86. In this way, the damper mechanism of the lower hopper unit 16 is opened by opening the shut-off valve 84 and introducing the atmospheric pressure in the lower chamber 90 of the lower hopper unit 16 into the deaeration chamber 80 of the middle hopper unit 14. The pressures before and after the 58 flap valves can be made equal, and the flap valves can be opened quickly.
[0017]
Next, an operation mode of the deaeration device 10 and an embodiment of the deaeration method of the present invention will be described with reference to the schematic diagram of FIG.
The deaeration device 10 can be installed, for example, in a deaeration station provided in the subsequent stage of the powder production line, and can be degassed continuously in the powder production process. Alternatively, it can be provided at the end of the pneumatic transport line.
Powder can be supplied to the upper hopper unit 12 of the deaerator 10 continuously or intermittently from a production line or an air transport line.
[0018]
At the start of the degassing cycle, the shutoff valves 68 and 76 of the upper and middle hopper units 12 and 14 are closed, respectively, but the shutoff valve 84 of the lower hopper unit 16 is open and the middle hopper unit 14 is removed. Atmospheric pressure is introduced into the air chamber 80 (FIG. 4 (1)).
All the flap valves are closed, and the powder is put into the hopper 24 of the upper hopper unit 12, and the powder evacuated in the previous cycle is put into the hopper of the lower hopper unit 16. .
[0019]
When the damper mechanism 30 of the upper hopper unit 12 is operated to open the flap valve 28, and when the damper mechanism 58 of the lower hopper unit 16 is operated to open the flap valve 92, the powder in the upper hopper 24 is opened. Is loaded into the hopper 96 of the middle hopper unit 14 and the powder in the lower hopper unit 16 deaerated in the previous cycle is discharged downward (FIG. 4 (2)).
Since the pressure before and after the flap valve 92 is equalized by opening the shut-off valve 84 in advance, the flap valve 92 is easily opened.
[0020]
Next, the flap valves 28 and 92 and the shut-off valve 84 are closed and the shut-off valves 68 and 76 are opened, so that the negative pressure from the vacuum source 66 is reduced to the deaeration chamber 32 and the middle hopper unit 14 of the upper hopper unit 12. Is applied to the deaeration chamber 80 (FIG. 4 (3)).
[0021]
When the deaeration chambers 32 and 80 before and after the flap valve 94 of the middle hopper unit 14 are in a vacuum or negative pressure atmosphere, the damper mechanism 56 of the middle hopper unit 14 is operated to open the flap valve 94. The powder in the hopper 96 of the middle hopper unit 14 is allowed to fall into the lower hopper unit 16 due to gravity, and accumulates in the lower hopper 98 (FIG. 4 (4)).
In the process of gravity dropping from the middle hopper unit 14 to the lower hopper unit 16, the powder falls in a vacuum in a dispersed state, so that the air between the particles is easily taken away and the powder is strong. Degassed and tightened.
[0022]
When the deaeration is completed, the flap valve 94 and the shutoff valves 68 and 76 are closed, the shutoff valve 84 is opened, and the atmospheric pressure is introduced into the deaeration chamber 80 (FIG. 4 (1)). By repeating the above steps, charging, degassing, and discharging of powder are performed in a batch manner.
[0023]
FIG. 5 shows a second embodiment of the deaeration method and apparatus of the present invention. This embodiment is characterized in that the degassing device comprises four hopper units and the powder is degassed twice during one cycle.
In FIG. 5, the same or equivalent components as those of the first embodiment described above are denoted by the same reference numerals, and redundant description is omitted.
[0024]
In this embodiment, a fourth hopper unit 100 similar to the first to third units 12, 14, 16 is connected under the third hopper unit 16, only the differences from the first embodiment will be described. The fourth unit 100 has a flap valve 102 and a lower chamber 104.
In this embodiment with four hopper units, the lower chamber 90 of the third unit 16 acts as a deaeration chamber. For this reason, the pressure introducing pipe 82 of the third unit 16 is connected to the vacuum source 66 through a conduit 108 having a shut-off valve 106.
The pressure introducing pipe 110 of the fourth unit 100 can be connected to the deaeration chamber 90 of the third unit 16 by a bypass conduit 86.
[0025]
In order to explain the operation of the second embodiment, the shutoff valve 76 can always be opened, and a negative pressure can be always applied to the deaeration chamber 80 of the second hopper unit 14.
Initially, all flap valves 28, 92, 94, 102 are closed, and negative pressure is applied to the deaeration chambers 80, 90 of the second and third hopper units 14, 16 by opening the shut-off valves 76, 106. (FIG. 5 (1)).
The hopper 24 of the first hopper unit 12 is charged with powder, and the hopper of the third hopper unit 16 contains the powder deaerated in the previous cycle.
[0026]
First, when the flap valve 28 of the first hopper unit 12 is opened and the flap valve 92 of the third hopper unit 16 is opened, the powder in the hopper 24 of the first hopper unit 12 is transferred to the hopper 96 of the second hopper unit 14. The powder in the third hopper unit 16 that has been charged and deaerated in the previous cycle is allowed to fall into the fourth hopper unit 100 and accumulates in the lowermost hopper (FIG. 5 (2 )).
At that time, in the process of falling from the third hopper unit 16 to the fourth hopper unit 100, the powder that has already been subjected to the first deaeration action in the previous cycle is further subjected to the second deaeration action. Tighten.
[0027]
Next, by closing all the flap valves 28, 92, 94, 102 and opening the shut-off valve 68, negative pressure from the vacuum source 66 is applied to the deaeration chamber 32 of the first hopper unit 12 (FIG. 5 ( 3)). In preparation for opening the flap valve 102, the shutoff valve 84 is opened to introduce atmospheric pressure into the deaeration chamber 90.
[0028]
Next, when the flap valve 94 of the second hopper unit 14 is opened, and when the flap valve 102 of the fourth hopper unit 100 is opened, the powder is reduced in the process of dropping from the first hopper unit 12 to the second hopper unit 14. While receiving the second deaeration action, the powder in the fourth hopper unit 100 is discharged downward (FIG. 5 (4)).
When the first deaeration is completed in this way, all the flap valves 28, 92, 94, 102 are closed, the atmospheric pressure introduction shut-off valve 84 is closed, and the negative pressure applying shut-off valve 106 is opened to open the third hopper unit 16. A negative pressure is applied to the deaeration chamber 90 (FIG. 5 (1)). By repeating the above steps, charging, degassing, and discharging of powder are performed in a batch manner.
[0029]
Although specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various changes and modifications can be made. For example, the silo 20 is not essential. Further, as the damper mechanism, a type that opens and closes the flap valve directly by an actuator can be used.
[0030]
【The invention's effect】
According to the present invention, since the powder is strongly degassed and tightened, the filling efficiency such as bagging can be improved and the distribution cost can be reduced. The present invention also contributes to preventing bridging and flushing during powder cutting and handling.
According to the present invention, as compared with the case of deaeration in a stationary state, it was possible to deaerate more strongly by 20 to 30% in a shorter time and in volume shrinkage.
If the deaeration is performed in two stages as in the second embodiment, the deaeration effect can be further enhanced.
[Brief description of the drawings]
FIG. 1 is a partially cutaway side view of a first embodiment of a deaeration device of the invention.
2 is a partially cutaway side view of the hopper unit of the deaeration device shown in FIG. 1. FIG.
3 is a perspective view of the damper mechanism of the hopper unit shown in FIG. 2 as viewed obliquely from below. FIG.
4 is a schematic view showing the operation of the first embodiment of the deaeration device shown in FIG. 1; FIG.
FIG. 5 is a schematic view showing the operation of the second embodiment of the deaeration device of the present invention.
[Explanation of symbols]
10: Deaerator
12, 14, 16, 100: Hopper unit 22: Main body 24: Hopper
30, 56, 58: Damper mechanism
32, 80, 90: Deaeration chamber
34/64/68; 72/74/76; 82/106/108: Negative pressure application means

Claims (2)

A powder deaerator for degassing powder by dropping it in a vacuum atmosphere while dispersing the powder:
Comprising at least three hopper units connected up and down in an airtight manner,
Each of the three hopper units is configured in the form of an interchangeable module with common components.
Each hopper unit defines a deaeration chamber in cooperation with a hopper having a powder discharge port, a damper mechanism for opening and closing the powder discharge port of the hopper, and a hopper of a lower hopper unit below the hopper. A cylindrical main body,
At least the uppermost and middle hopper units include means for applying a negative pressure to the deaeration chamber at a predetermined time,
The damper of the uppermost hopper unit was opened, the powder was loaded into the hopper of the middle hopper unit, the damper of the uppermost hopper unit was closed, and negative pressure was applied to the deaeration chambers of the uppermost and middle hopper units. After that, by opening the damper of the middle hopper unit, the powder is removed by dropping the powder in a dispersed state across the deaeration chamber under the negative pressure of the middle hopper unit to the hopper of the lowermost hopper unit. A powder degassing device characterized by concern. A lower hopper unit, further comprising: a fourth hopper unit connected below the lowermost hopper unit; and means for applying a negative pressure to a deaeration chamber of the lowermost hopper unit at a predetermined time. 2. The powder according to claim 1, wherein the powder is further degassed by dropping the powder in a dispersed state across the degassing chamber under a negative pressure of the fourth hopper unit. Deaeration device.

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