JP2002210805A - Fine powder raw material supplying apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a high transporting capability to be stably maintained by sufficiently forcibly exhausting air and gas mixed in a fine powder raw material in a barrel. SOLUTION: A fine powder raw material supplying apparatus 1 comprises the barrel 2 and two screws 3 arranged in the barrel 2. Thus, the fine powder row material supplied by a hopper provided at a rear end side is conveyed, and supplied to an extruder from a discharge port provided at a distal end. Vent ports 8 are oppositely provided at both sidewalls, as shown, between the port of the barrel 2 and the hopper. A screen unit 10 is provided at each port 8. An outer wall surface side opening of each port 8 communicates with a forcible exhaust chamber 20. The unit 10 has a receiving member 12, a screen 22 having smaller network than a mean particle size of the raw material, and a retaining member 13 for bringing the screen 1 into close contact with a porous plate-like bent wall 12a of the member 12 and having a lattice-like retaining plate for forming a vent channel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for supplying a fine powder material to an extruder for mixing and extruding a fine powder material having a low bulk density with a polymer.

[0002]

2. Description of the Related Art An example of a conventional fine powder material supply apparatus used in an extruder for mixing and extruding a fine powder material having a low bulk density with a polymer will be described.

As shown in FIG. 6, an extruder 201 comprises a heating cylinder 202, two interlocking screws 203 rotatably disposed in a heating cylinder 202, and two screws 203 in the same direction. Alternatively, a rotation driving mechanism (not shown) for rotating in the opposite direction is provided, and a fine powder raw material supply port 204 provided on the side wall of the heating cylinder 202 on the upstream side of the kneading section.

On the other hand, a fine powder raw material supply apparatus 101 has a discharge port 102a at a front end and a hopper 104 at a rear end side.
A hopper 104 provided with a barrel 102 having a screw shaft, two meshing screws 103 rotatably disposed in the barrel 102, and a rotation drive mechanism 105 for rotating the two screws 103 in the same direction or in the opposite direction. Is provided with a gas vent port 106, and a discharge port 102a of the barrel 102 is connected to a heating cylinder 202 of the extruder 201.
Is connected to the fine powder raw material supply port 204.

[0005] In this conventional fine powder raw material supply apparatus 101, after the mixed air is forcibly exhausted through the gas vent 106, the fine powder raw material charged into the hopper 104 is removed.
It is transferred to the tip side by two screws 103 rotating in the same direction or the opposite direction in the barrel 102, and supplied into the heating cylinder 201 from the discharge port 102a through the fine powder material supply port 204 of the extruder 201. 201
Extruded after being mixed with the polymer.

[0006]

In the above-mentioned prior art, air mixed with the fine powder material supplied to the hopper is forcibly exhausted through a gas vent provided in the hopper. Air in the hopper cannot be sufficiently removed, and the amount of air in the fine powder in the hopper increases, reducing the bulk density of the fine powder. Will decrease. As a result, the supply amount of the fine powder raw material to the extruder becomes unstable. In addition, when the volatile components in the polymer gasify in the extruder and flow back into the barrel of the fine powder material supply device, there is a problem that the transport capacity of the fine powder material supply device is extremely reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has a feature of sufficiently forcibly exhausting air and gas mixed in a fine powder material in a barrel to stabilize a high transportation capacity. It is an object of the present invention to provide a fine-powder material supply device for supplying the fine-powder material to an extruder that mixes and extrudes a fine-powder material having a low bulk density with a polymer, which can be maintained.

[0008]

In order to achieve the above object, a fine powder raw material supply apparatus according to the present invention comprises a fine powder raw material having a low bulk density mixed with a polymer and extruded from the extruder. A fine powder raw material supply device, wherein the fine powder raw material supply device has a discharge port connected at one end to a fine powder raw material supply port provided on a side wall of a heating cylinder of the extruder and a hopper at the other end side. When,
A screw rotatably disposed in the barrel, a rotary drive mechanism for rotating the screw, at least two vent ports provided in a wall between the hopper and the discharge port in the barrel, and the vent A forced exhaust chamber communicated with the opening on the barrel outer wall side of the mouth, and a screen unit mounted on the vent port, wherein the screen unit has a perforated plate shape substantially flush with the inner wall surface of the barrel. A curved wall and a box-shaped receiving member whose surface facing the curved wall is open, and a screen having a mesh smaller than the average particle diameter of the fine powder material covering the curved wall,
And a pressing member having a lattice-shaped pressing plate that forms a vent flow path while bringing the screen into close contact with the curved wall of the receiving member.

Further, a cooling jacket for flowing a cooling medium is provided inside the barrel wall.

Further, one end of an air supply duct is connected to the forced exhaust chamber via an air supply valve, and pressurized air or inert gas is instantaneously supplied through the air supply duct to screen the air. So that backwashing can be performed.

Further, a pressure gauge for detecting the internal pressure is provided in the forced exhaust chamber.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a fine powder raw material supply apparatus according to the present invention will be described.

As shown in FIG. 1, a fine powder raw material supply device 1
Is a barrel 2 having a discharge port 2a at the front end and a hopper 4 at the rear end side, two meshing screws 3 rotatably disposed in the barrel 2, and two screws 3 And a rotation driving mechanism 5 for rotating the extruder 41 in the same direction or in the opposite direction. I have.

As shown in FIG. 2, vent holes 8 penetrating from the outer wall surface to the inner wall surface are provided on both sides of the barrel 2 between the discharge port 2a and the hopper 4 as shown in FIG. A screen unit 10, which will be described later, is mounted in the inside 8, and the outer wall side opening of each vent 8 is connected to the forced exhaust chamber 20.

Further, a cooling jacket 6 is provided in the wall of the barrel 2 avoiding the vent port 8, and when the fine powder material has a low melting point, a cooling medium is flowed through the cooling jacket 6 to cool the material. It is configured to be able to.

Each forced exhaust chamber 20 has an exhaust valve 21
One end of the exhaust duct 22 is connected via
The other end of the exhaust duct 22 is connected to a forced exhaust means (not shown).

In this embodiment, each forced exhaust chamber 20 is provided with an air supply duct 2 through an air supply valve 23.
4 is connected to one end.

Each forced exhaust chamber 20 is provided with a viewing window 26 for observing the inside and a pressure gauge 25 for detecting the internal pressure.

Further, a pressure gauge 27 is provided on the downstream side of the vent port 8 in the barrel 2, and the pressure gauge 27 is used by the pressure gauge.
When an abnormal pressure in the inside is detected, the signal can be sent to a control system and used for safety measures such as stopping the operation.

In addition, a level sensor 28 is provided in the hopper 4, and the level sensor 28 detects the level of the raw material in the hopper, thereby controlling the transport capacity.

As shown in FIGS. 3 and 4, the screen unit 10 has a perforated plate-like curved wall 12a having a radius of curvature substantially equal to the inner wall surface 2b of the barrel 2, and the surface facing the curved wall 12a is open. A box-shaped receiving member 12, a screen 11 having a shape that covers the curved wall 12 a of the receiving member 12 and having a mesh smaller than the average particle size of the fine powder raw material, Grid-shaped holding plate 1 that forms a vent channel
3b having a pressing member 3b.

The holding member 13 has a shape that can be removably inserted into the receiving member 12 and has an open outer surface 13a and a grid-like holding member integrally provided in the outer frame 13a. Screen 1 of the holding plate 13b
The tip 13c which abuts on the screen 1
Curved wall 12a so that it can be held in close contact with
It is curved like.

In the present embodiment, a flange 12c is provided on the open edge of the receiving member 12, and a flange 13d is also provided on the pressing member 13, and the pressing member 13 is inserted into the receiving member 12. Then, the both flanges 12c and 13d are made to overlap each other, and the two flanges 12c and 13d are detachably fixed using detachable fixing means such as screws (not shown). For this reason, the screen 11 can be replaced freely, and when the screen 11 is damaged, it can be replaced with a new screen 11.

Since the screen unit 10 is configured as described above, the curved wall 12 a of the perforated plate of the receiving member 12 is formed by the inner wall surface 2 of the barrel 2.
When the inside of the vent 8 is mounted so as to be substantially flush with the surface b, the opening on the inner wall surface side of the barrel 2 of the vent 8 is covered with the screen 11. As a result, the fine powder material in the barrel 2 does not pass, but the mixed air and gas pass and flow into the forced exhaust chamber 20.

When the gap between the perforated curved wall 12a and the flight outer peripheral surface of the screw 3 is set to 1 mm or less, the self-cleaning property of the curved wall 12a is improved.

Next, the operation of the fine powder raw material supply apparatus according to the present embodiment will be described.

During normal operation, the air supply valve 23 of each forced exhaust chamber 20 is closed, the exhaust valve 21 is opened, and the exhaust duct 22 and the forced exhaust chamber 20 communicate with each other. The forced evacuation unit 20 is set to a forced evacuation state in which the forced evacuation chamber 20 is depressurized.

The fine powder raw material supplied to the hopper 4 enters the barrel 2 after a part of the mixed air is forcibly evacuated from the gas vent 7 provided in the hopper 4, and then the two rotating powders are rotated. It is conveyed by the screw 3 toward the discharge port 2a.

When the fine powder raw material enters the barrel 2 from the hopper 4, the air in the hopper 4 is swirled and mixed into the fine powder raw material. It flows through the mesh of the screen 11 of the unit 10 to the forced exhaust chamber 20 as shown by the arrow,
The air is forcibly exhausted through the exhaust duct 22.

As a result, the fine powder raw material conveyed in the barrel 2 toward the discharge port 2a is prevented from lowering in bulk density due to the incorporation of air, and the fine powder raw material feeding device 1 is reduced in the fine powder raw material transporting ability. Instead, a fixed amount of the fine powder raw material is stably supplied from the fine powder raw material supply port 44 of the screw type extruder 41.

When the screen 11 is clogged, the exhaust valve 21 is closed, the air supply valve 23 is opened, and the air supply duct 24 and the forced exhaust chamber 20 are communicated with each other. Air or an inert gas pressurized through the use duct 24 is supplied instantaneously (pulse supply) into the forced exhaust chamber 20. Instantaneous supply into pulsed exhaust chamber 20 (pulse supply)
The pressurized air or inert gas flows back through the screen unit 10 and blows the fine powder material clogged in the mesh of the screen 11 into the barrel 2. That is, clogging of the screen is eliminated by performing back washing.

It is needless to say that this back washing can be performed for each screen unit 10 of each vent 8.

Next, another embodiment of the fine powder raw material supply apparatus according to the present invention will be described. As shown in FIG. 5, the fine powder raw material supply device 31 according to the present embodiment is provided with two vent ports 8 facing each other on both side walls of the barrel 2,
Two vent ports 8 are provided side by side on the illustrated upper wall of the barrel 2, and the opening on the barrel outer wall side of each vent port 8 communicates with the forced exhaust chamber 20. Except for this point, the apparatus is the same as the fine powder material supply apparatus according to the above-described embodiment, and a description thereof will be omitted.

In each of the embodiments described above,
Although one having two meshing screws in the barrel 2 has been described, the present invention is not limited to this, and one having two screws in the barrel 2 and two non-meshing type screws in the barrel 2 may be used. It goes without saying that the present invention can be applied to a device having a screw.

Further, the number of vent ports is not limited to two or four shown in each of the above embodiments, but may be three if necessary.
Or 5 or more.

[0036]

Since the present invention is configured as described above, the following effects can be obtained.

In order to forcibly exhaust air or gas mixed in the fine powder raw material through a screen having a mesh smaller than the average particle diameter of the fine powder raw material of the screen unit mounted on the vent port provided in the barrel, the fine powder in the barrel is removed. A decrease in bulk density of the raw material is prevented, and a high transport capacity can be maintained. As a result, the size can be reduced, and the fine powder material can be stably supplied to an extruder that mixes and extrudes the fine powder material with the polymer.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a fine powder raw material supply device according to an embodiment.

FIG. 2 is a schematic sectional view taken along line AA of FIG.

FIG. 3 is a schematic perspective view showing a screen unit in the fine powder raw material supply device shown in FIG. 1 with a part cut away.

FIG. 4 is an exploded schematic perspective view showing the screen unit shown in FIG. 3;

FIG. 5 is an explanatory diagram of a fine powder raw material supply device according to another embodiment.

FIG. 6 is an explanatory view showing an example of a conventional fine powder material supply device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 31 Fine powder raw material supply apparatus 2 Barrel 3 Screw 4 Hopper 5 Rotation drive mechanism 6 Cooling jacket 7 Gas vent 8 Vent port 10 Screen unit 11 Screen 12 Receiving member 12a Curved wall 12b Hole 12c Flange 13 Pressing member 13a Outside Frame 13b Holding plate 13c Tip 20 Forced exhaust chamber 21 Exhaust valve 22 Exhaust duct 23 Air supply valve 24 Air supply duct 25, 27 Pressure gauge 26 Viewing window 28 Level sensor 41 Extruder 42 Heating cylinder 43 Screw 44 Fine powder raw material Supply port

Claims (4)

[Claims] An extruder (41) for mixing and extruding a fine powder material having a low bulk density into a polymer, and supplying the fine powder material to an extruder (41). The apparatus has a barrel (2) having at one end a discharge port (2a) connected to a fine powder material supply port (44) provided on a side wall of a heating cylinder of the extruder, and having a hopper (4) at the other end. A screw (3) rotatably disposed in the barrel, a rotation drive mechanism (5) for rotating the screw, and at least two screws provided on a wall between the hopper and the discharge port in the barrel. A vent unit (8), a forced exhaust chamber (20) communicated with an opening on the barrel outer wall side of the vent port, and a screen unit (10) attached to the vent port. Knit becomes substantially flush with the inner wall of the barrel perforated plate-like curved wall (12a) and said opposing surface to the curved wall opens a box-shaped receiving member (12)
A screen (11) having a mesh smaller than the average particle size of the fine powder raw material covering the curved wall, and a grid-like presser for bringing the screen into close contact with the curved wall of the receiving member and forming a vent channel. A feeder (13) having a plate (13b). 2. The fine powder raw material supply device according to claim 1, wherein a cooling jacket (6) for flowing a cooling medium is provided inside a wall of the barrel (2). 3. One end of an air supply duct (24) is connected to a forced exhaust chamber (20) via an air supply valve (23), and compressed air or air is supplied through the air supply duct. 3. The screen according to claim 1, wherein an inert gas is supplied instantaneously to backwash the screen.
The fine powder raw material supply apparatus according to the above. 4. The fine powder raw material supply device according to claim 1, wherein a pressure gauge (25) for detecting an internal pressure is additionally provided in the forced exhaust chamber (20).