JPH09142633A - Screw conveyer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To guide powder always to the center of a dropping discharge port by providing the first screw impeller for transferring powder from its dropping port to its dropping discharge port and the second impeller for transferring the powder in the direction opposite to the direction in the case of the first impeller. SOLUTION: The second screw impeller 6 is formed on the outer periphery of a part between the dropping discharge port 8 in a rotary shaft 13 and the end wall 2c of a casing 2 and its has been so designed that the powdery may be transferred in the direction opposite to that of the first screw impeller 3 when the rotary shaft 13 is rotated. Accordingly, powder in the upper space inside of a screen 5 is pushed out to the end wall 2c side by powder continuously fed by the first screw impeller 3, but pushed back to the screen 5 side by means of the second screw impeller 6. As the result, the powder is given such trend to always move toward the center of a dropping dishrag port 8 by means of the first and the second screw impellers 3, 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a screw conveyor for transferring powders such as powdered foods, fertilizers, dyes and pharmaceutical raw materials.

[0002]

2. Description of the Related Art As is well known, a screw conveyor is used when transferring powdered foods, fertilizers, dyes, raw materials for pharmaceuticals and the like. A general screw conveyor has a casing having a powder supply port at one end and a powder drop discharge port at the other end, and a casing provided in the casing and around an axis extending in the longitudinal direction of the casing. It is configured to transfer the powder supplied from the supply port to the drop discharge port by the rotation of the screw blade and discharge the powder from the drop discharge port to the outside.

[0003]

In the conventional screw conveyor described above, the powder easily aggregates when the powder having a high water content such as food is transferred, and the aggregated powder is clogged near the drop discharge port. The powder cannot be transferred, and the load on the motor that drives the screw blades increases, causing a problem that the motor fails. In addition, there is a problem that when the powder aggregates to form an aggregate, the discharge amount of the powder varies.

The present invention has been made to solve the above problems, and its purpose is to crush agglomerated powder to make the powder smooth and uniform in size. Another object of the present invention is to provide a screw conveyor that can be discharged quantitatively.

[0005]

In order to achieve the above object, a screw conveyor of the present invention comprises a casing having a powder supply port at one end and a powder drop discharge port at the other end. A first screw blade provided in the casing for transferring the powder from the supply port to the drop discharge port by rotating about an axis extending in the longitudinal direction of the casing; A rotating body which is provided above the drop discharge port and which has an agitating blade on the outer periphery for imparting a component force to the powder in the radial direction of the rotation, and a lower outer periphery of the rotating body to contact the agitating blade. So as not to face the first screw blade with the rotating body sandwiched in the casing and a screen for crushing the aggregated powder in cooperation with the stirring blade. And a second screw blade for transferring the powder in a direction opposite to the first screw blade by rotating around an axis extending in the longitudinal direction of the casing. Is.

The material and shape of the screen are not particularly limited, but those having an aperture ratio of 35% or more are preferable, and those having an aperture ratio of 40% or more are more preferable. That is, the screen of the present invention is for crushing the agglomerated powder, and is not the one for compression-molding the powder to a desired particle size by extruding the powder from the opening like the screen of a granulator. Alternatively, the powder need not be compressed as it passes through the opening. Therefore, it is preferable to increase the aperture ratio of the screen as much as possible to reduce the powder extrusion pressure and reduce the load on the drive source of the rotating body.

When the screen is a wire mesh, it is formed of a linear member having a circular cross section, so that the pressure for pushing out the powder is reduced and the powder is not clogged in the opening. Further, since the wire mesh is flexible, the load on the drive source of the rotating body is reduced, and the wire mesh is easy to handle at the time of disassembly and assembly.

A cross section U in which the screen is opened upward
It is preferable to form the shape in a V shape because the powder agitated by the agitating blades can escape upward and the load on the drive source of the rotating body can be reduced.

The material, shape, and number of the stirring blades are not particularly limited. However, if the stirring blades have elasticity, the stirring blades bend when the resistance to push the powder out of the screen is large, and the stirring blades serve as a drive source for the rotating body. Such a burden is reduced, which is preferable. Examples of such materials include rubber, plastic, and spring materials such as steel and stainless steel.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. 1 is a front view of a screw conveyor which is an embodiment of the present invention, FIG. 2 is a right side view of the screw conveyor of FIG. 1, FIG. 3 is a sectional view taken along line AA of FIG. 2, and FIG. 4 is B of FIG. -B line sectional view, FIG. 5 is C of FIG.
FIG.

1 to 4, this screw conveyor is for transferring powdered foods, fertilizers, dyes, powders of pharmaceutical materials, etc., and wheels 1a for movement are provided at the four corners of the lower surface.
A machine casing 1 having a casing 2, a casing 2 provided on the machine casing 1,
A first screw blade 3 provided in the casing 2,
The rotary body 4, the screen 5, and the second screw blade 6 are provided.

The casing 2 is a trough having a U-shaped cross section with an open upper surface, extends in the horizontal direction, and the upper surface is closed by a removable lid 2a. The casing 2 has a powder supply port 7 on one end side and a powder drop discharge port 8 on the other end side. The casing 2 has both end walls 2
The brackets 9 and 10 horizontally project from the b and 2c.
1 and 12 are fixed.

A rotary shaft 13 extending in the longitudinal direction of the casing 2 is provided inside the casing 2.
Both ends of 3 project outside the casing 2 and are rotatably supported by bearings 11 and 12, respectively. One end of the rotary shaft 13 is connected to the rotary shaft of a motor 14 fixed to the upper surface of the machine frame 1, and when the motor 14 is driven, the rotary shaft 13 rotates in the arrow direction of FIG. The first screw blade 3 is formed on the outer circumference of the portion of the rotary shaft 13 between the supply port 7 and the drop discharge port 8. When the rotary shaft 13 rotates, powder is dropped from the supply port 7 to the discharge port. It is designed to be transferred to 8.

The rotating body 4 is provided above the drop discharge port 8 and is fixed to the rotating shaft 13 so as to face each other at intervals in the direction of the center line L of the rotating shaft 13. 15, 16 and a plate-shaped stirring blade 18 attached to an arm 17 fixed to the outer periphery of the frames 15, 16 at equal angular intervals and extending parallel to the center line L of the rotary shaft 13. The arm 17 is fixed to the frames 15 and 16 in a state of being tilted in the rotation direction, and the stirring blade 18 is provided at the tip of the arm 17 and the tip of the stirring blade 18 is located behind the extension line of the arm 17 in the rotation direction. It is attached by a bolt 19 so that

The screen 5 is made of wire mesh, and as shown in FIG. 4, is formed in a U-shaped cross section with an opening at the top.
The semicircular bottom covers the lower outer periphery of the rotating body 4.
The bottom radius of the screen 5 is slightly larger than the maximum radius of the rotating body 4, and a gap a is formed between the screen 5 and the tip of the stirring blade 18.

When the rotating body 4 rotates in the direction of the arrow, the powder is pressed against the screen 5 by the stirring blade 18, and the powder is screened by the component of the force given to the powder by the stirring blade 18 to the outside in the radial direction of rotation. The powder is pushed out from the opening of No. 5, and the agglomerated powder is crushed.

As shown in FIG. 5, the stirring blade 18 is provided with a hole 18a through which the threaded portion of the bolt 19 passes.
The hole 18a is formed in a long hole shape so as to extend in the width direction of the stirring blade 18. Attach the stirring blade 18 to this mounting hole 18
By moving in the longitudinal direction of a, the size of the gap a between the tip of the stirring blade 18 and the screen 5 can be adjusted. In this embodiment, since the stirring blade 18 is slid with respect to the screen 5 surface, the size of the gap a can be adjusted with high accuracy.

The second screw blade 6 is formed on the outer circumference of the portion of the rotary shaft 13 between the drop discharge port 8 and the end wall 2c of the casing 2, and when the rotary shaft 13 rotates in the direction of the arrow in FIG. The powder is transferred in the direction opposite to the first screw blade 3 (leftward in FIG. 1).

Next, the operation of the screw conveyor constructed as described above will be described. The powder supplied from the supply port 7 is transferred to the drop discharge port 8 in the casing 2 by the first screw blades 3 which rotate in a predetermined direction by the motor 14, and is moved to the screen above the drop discharge port 8 at a position above the screen. Drop into 5. The powder in the screen 5 is agitated by the agitating blades 18 of the rotating body 4 rotating in a predetermined direction and pressed against the inner surface of the screen 5,
Is pushed out of the opening.

The powder agglomerated before being charged into the screw conveyor and when being transferred by the first screw blade 3 is stirred by the stirring blade 18 and extruded from the opening of the screen 5 to be crushed. Therefore,
The powder is smoothly discharged to the outside without getting stuck in the drop discharge port 8. Further, by crushing the agglomerated powder, the particle size of the powder becomes substantially uniform, and the discharge amount of the powder becomes stable.

The upper powder in the screen 5 is pushed out toward the end wall 2c by the powder continuously fed by the first screw blade 3, but is moved toward the screen 5 side by the second screw blade 6. Pushed back. Since the powder is always directed toward the center of the drop discharge port 8 by the first and second screw blades 3 and 6, the stirring blade 1
8, the amount of powder pressed against the screen 5 is averaged, the load on the motor 14 is stabilized, and the variation in the amount of powder discharged is reduced. Further, by providing the second screw blade 6, it is possible to prevent the end portion of the casing 2 from being clogged with powder.

In the above screw conveyor, the number of rotations of the motor, the discharge capacity, and the value of the motor drive current were measured under the following conditions, and the results shown in the graphs of FIGS. 6 and 7 were obtained. Powder: Food additive Average particle size = 32.6 μm Specific gravity = 0.4 g / cm Motor: Output = 0.4 kw Screw blade: Diameter = 75 mm Rotating body: Rotation locus diameter of tip of stirring blade = 125 mm Screen: Mesh = 16 (number of meshes / inch) Opening = 1138 μm

As shown in FIG. 6, the discharge capacity increases linearly with the increase of the rotation speed of the motor, and as shown in FIG. 7, the drive current value of the motor increases linearly with the increase of the discharge capacity. Is increasing. In other words, it can be seen that the screw conveyor of the present invention is capable of smoothly transferring the powder without causing a jam even when it is driven at a high speed.

In the above embodiment, the first screw blade 3, the rotating body 4, and the second screw blade 6 are driven by the single motor 14. However, the rotating body 4 and the second screw blade 6 are connected to each other. The motors may be driven by different motors, or the first screw blade 3, the rotating body 4, and the second screw blade 6 may be driven by different motors.

Further, although the case where the food additive is transferred has been described in the present embodiment, the kind of powder transferred by the screw conveyor of the present invention is not limited to this, and for example, a raw material for a dye or a pigment. , Fertilizer, feed, corn starch, pulp, wood powder, fibrous material, rubber, synthetic resin powder, carbon black, pharmaceutical raw materials, titanium oxide, zinc oxide, manganese dioxide, aluminum oxide, etc. .

[0026]

As described above, in the screw conveyor of the present invention, the agglomerated powder is agitated by the agitating blades of the rotating body and crushed by being extruded from the opening of the screen by the agitating blades. The body is not clogged, and the powder can be smoothly discharged into particles of a uniform size. Further, since the powder is always directed toward the center of the drop discharge port by providing the second screw blade, the amount of the powder pressed against the screen by the stirring blade is averaged, and the motor is applied. The load is stable, and the variation in the amount of powder discharged is reduced.

According to the second aspect, since the pressure when the powder is pushed out from the opening of the screen becomes small, the powder can be transferred more smoothly and the load on the drive source of the rotating body is reduced. , Drive source failure is reduced.

According to the third aspect of the present invention, since the wire net is formed by the linear body having a circular cross section, the powder pushing pressure becomes small and the powder is not clogged in the opening. Therefore, the time and labor required for cleaning are reduced, and when the food powder is transferred, no powder remains on the screen, which is hygienic. Further, since the wire mesh is flexible, the load on the drive source of the rotating body is reduced, the drive source is less likely to malfunction, and the wire mesh is easy to handle during disassembly and assembly.

According to the present invention, the powder can escape upward when the powder is stirred by the stirring blade, and the load on the drive source of the rotating body is reduced, so that the drive source is less likely to malfunction. Become.

According to the fifth aspect of the invention, when the powder having a large extrusion pressure is used, the stirring blade is bent and the load on the drive source of the rotating body is reduced, so that the drive source is less likely to malfunction.

[Brief description of the drawings]

FIG. 1 is a front view of a screw conveyor that is an embodiment of the present invention.

FIG. 2 is a right side view of the screw conveyor shown in FIG.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a sectional view taken along line BB of FIG.

5 is a view taken along the line CC of FIG.

6 is a graph showing the relationship between the rotation speed of the motor of the screw conveyor of FIG. 1 and the discharge capacity.

7 is a graph showing the relationship between the discharge capacity of the screw conveyor of FIG. 1 and the drive current value of a motor.

[Explanation of symbols]

 2 Casing 3 First screw blade 4 Rotating body 5 Screen 6 Second screw blade 7 Supply port 8 Drop discharge port 18 Stirring blade L axis line (center line)

Claims (5)

[Claims] 1. A casing having a powder supply port on one end side and a powder drop discharge port on the other end side; and a casing provided in the casing, around an axis extending in the longitudinal direction of the casing. A first screw blade that transfers the powder from the supply port to the drop discharge port by rotating;
A rotor provided in a position above the drop discharge port in the casing and having an agitating blade on the outer periphery for imparting a force component to the powder in the radial direction of rotation, and a lower outer periphery of the rotor and A screen that is stretched so as not to come into contact with the stirring blade and that disaggregates the agglomerated powder in cooperation with the stirring blade, and that faces the first screw blade with the rotating body sandwiched in the casing. And a second screw blade for transferring powder in a direction opposite to the first screw blade by rotating around an axis extending in the longitudinal direction of the casing. Screw conveyor. 2. The screw conveyor according to claim 1, wherein the opening ratio of the screen is 35% or more. 3. The screw conveyor according to claim 1, wherein the screen is a wire mesh. 4. The screw conveyor according to claim 1, wherein the screen has a U-shaped cross-section with an upper opening. 5. The screw conveyor according to claim 1, wherein the stirring blade has elasticity.