JP7541320B2 - Screw feeder - Google Patents

Description

The present invention relates to a screw feeder that improves the utilization efficiency, and in particular to an apparatus that improves the transport efficiency in a hopper and enables a constant supply of material while avoiding an increase in resistance caused by the direct pressure of the material being transported in the hopper.
This relates to a device that prevents clogging of transported goods in a hopper, which has conventionally occurred by installing a direct pressure prevention plate or the like, and achieves efficient transportation.

Conventionally, in a screw feeder, the direct pressure of the material stored in the hopper is applied to the screw feeder, and resistance is generated when the material to be transported is moved and fed from the direct pressure.
For this reason, direct pressure prevention plates are sometimes installed inside the hopper to disperse the direct pressure, but with viscous transported materials (stored materials), bridges can form inside the hopper, often causing blockages, so careful consideration is required. Also, even if direct pressure prevention plates are used, there is much doubt as to whether they will necessarily be effective in preventing direct pressure.

In screw feeders, the materials are moved by rotating blades inside a trough (case). The gap between the trough and the blades is often around 10 to 30 mm, and the materials can accumulate between the blades and the trough of the screw feeder with no gap between them.
As a result, sticky transported objects caught in the gap could encounter considerable resistance due to friction between the trough and the blades.

In addition, when transported goods got caught in the gap, the sticky transported goods sometimes stuck to the trough and became difficult to move.
Furthermore, since the blades of the screw feeder rotate while feeding the material, frictional resistance is generated between the material and the blades.

For this reason, in the design stage, the screw diameter, screw pitch, rotation speed, required horsepower (motor), and torque were often determined from experience based on the transport volume, transported material, moisture content, and apparent specific gravity.
In addition, the bearing shaft diameter, roller chain, and frame strength were determined based on the torque.

The screw conveyor and screw feeder themselves have a very simple structure consisting of just a screw shaft and blades. If a problem occurs, such as insufficient torque or an excess or deficiency in the transport volume, the only solution is to change the blade diameter or the rotation speed.
Furthermore, if the torque is insufficient, the only solution is to change the motor horsepower, etc. The biggest problem is that if the torque is insufficient and the motor horsepower must be increased, the screw shaft diameter often also needs to be increased, necessitating redesign and re-production.

If the torque is excessive, the blade diameter can be changed to reduce the torque and therefore the resistance. When changing the blade diameter, the blade is often cut to a smaller size on-site.
In addition, in many cases, a transmission is installed from the start to deal with fluctuations in the loading rate of the transported goods.

JP 5-24659 A "Screw Feeder" This document shows a structure including a main screw 16 and a sub-screw 21 extending parallel to the main screw 16. However, this structure requires energy to rotate the sub-screw, and the sub-screw only has the function of actively transporting the material in the reverse direction of the screw groove 16b upstream of the main screw, but does not have the function of reducing the direct pressure of the retained material, nor does it have the function of directly transporting the retained material.

By placing a screw conveyor in place of a direct pressure prevention plate, rotation control and balance are achieved, and the material can be transported by both the screw conveyor and the screw feeder, making it possible to operate the screw feeder more lightly.
In addition, this screw feeder is equipped with a screw conveyor that prevents direct pressure on the stored material and also serves as a direct pressure prevention device.

In addition, the casing of the screw conveyor can be extended to the outside to drive the screw conveyor, transport the transported material, and help the screw feeder transport volume while preventing direct pressure.

This screw conveyor does not have a casing (trough) inside the hopper, so the material being transported in the gap is not subjected to much friction between the trough and the blades, and there is less direct pressure, which reduces resistance, and because there is less direct pressure, there is also less frictional resistance.
Low direct pressure is the same phenomenon as imagining a place with high water pressure, where the same pressure is applied from all directions, and since there is no casing, the transported items have an escape route.

In the first invention of the present invention, in a hopper for storing retained material, a trough is provided at the bottom of the hopper, and a single-shaft or multiple-shaft screw feeder is installed inside the trough, and the screw feeder is supported by a driving shaft side bearing and a driven shaft side bearing, and transmits power from the drive motor to the driving chain wheel, and is composed of a driving shaft that rotates the screw feeder and a driven shaft that supports the rotation, and retained material can be discharged from a discharge outlet provided at the end of the trough. Also, a single-shaft or multiple-shaft screw conveyor is installed at a vertical intermediate position of the hopper, spaced apart from the screw feeder , and the screw conveyor is supported by a driving shaft side bearing and a driven shaft side bearing, and transmits power from the drive motor to the driving chain wheel, and is composed of a driving shaft that rotates the screw conveyor and a driven shaft that supports the rotation, and one end of the screw conveyor is surrounded by a casing, and retained material can be discharged from a discharge outlet provided at the end of the casing.

The second invention is a screw feeder that allows the stored material discharged from a discharge port provided at the end of the casing to join the middle of the trough and discharge the stored material from a discharge port provided at the end of the trough.

As a third invention, the accumulated material discharged from the discharge port at the end of the casing is merged into a trough, and a screw feeder is provided with a larger spacing between the blades of the screw feeder at the merge position.

In addition, as a fourth invention, in a hopper for storing accumulated material, a trough is provided at the bottom of the hopper, and a single-shaft or multiple-shaft screw feeder is installed inside the trough, and the screw feeder is supported by a driving shaft side bearing and a driven shaft side bearing, transmits power from a drive motor to a driving chain wheel, and is composed of a driving shaft that rotates the screw feeder and a driven shaft that supports the rotation, and accumulated material can be discharged from a discharge port provided at the end of the trough, and a single-shaft or multiple-shaft screw conveyor is installed on the top of the screw feeder, and the screw conveyor is supported only by a driving shaft side bearing, transmits power from the drive motor to the driving chain wheel, and is composed of a driving shaft that rotates the screw conveyor, and is provided with a plate that supports the blades of the screw conveyor. One end of the screw conveyor is surrounded by a casing, and the accumulated material can be discharged from a discharge port provided at the end of the casing.

By preventing direct pressure, this invention makes it possible to reduce the total power required and equalize the transport volume. By extending the casing of the screw conveyor to the outside, it is possible to drive the screw conveyor, transport the transported material, and help the screw feeder transport volume while preventing direct pressure.

In addition, since this screw conveyor does not have a casing (trough) inside the hopper, there is no resistance and little direct pressure, making it easy to transport objects.
In addition, since there is little direct pressure from the transported goods, the blades rotate while transporting the transported goods, which reduces frictional resistance between the transported goods and the blades.

FIG. 1 is an explanatory diagram of a screw feeder according to the present invention; Illustrative cross-sectional view of the screw feeder of the present invention. FIG. 1 is an explanatory diagram of another screw feeder according to the present invention; FIG. 1 is an explanatory diagram of another screw feeder according to the present invention; Illustrative cross-sectional view of the screw feeder of the present invention. Illustrative diagram of the screw conveyor of the present invention. Diagram of a conventional screw feeder Cross-sectional view of a conventional screw feeder

When the accumulated material is above the position of the upper screw conveyor, the screw conveyor is operated simultaneously with the screw feeder.
Both are operated and adjusted so that the total is the specified amount. Both can be controlled to the appropriate rotation using an inverter.

When the accumulated material falls to the center level of the upper screw conveyor, the screw conveyor stops operating and the lower screw feeder starts operating alone.

An inverter is used to adjust the rotation speed to the appropriate level so that the specified amount can be achieved using only the screw feeder.

If the exit of the upper screw conveyor is located just before the exit of the screw feeder, the spacing between the blades of the screw feeder at the joining point of the screw feeders is increased to increase the conveying volume of the screw feeder.

In Figure 1, 1 is a hopper that can store materials. Materials that can be stored include sticky materials and sludge.

2 is a trough, which is located at the bottom of the hopper 1 and is capable of transporting the stored material (transported material). 3 is a screw feeder, which can have one or more shafts inside the trough 2. The screw feeder 3 is provided with a screw shaft 4 and blades 5. This screw feeder 3 can also be composed of only the blades 5 without the screw shaft.

6 is a drive motor, which is a drive source that rotates the screw feeder 3. 7 is a drive chain wheel, which receives drive from the drive motor 6 and transmits power to a drive shaft 9 supported by a drive shaft side bearing 8, thereby rotating the screw feeder 3. In addition, the screw feeder 3 is held by a driven shaft 11 supported by a driven shaft side bearing 10.

12 is a screw conveyor, which is located above the screw feeder 3 and can have one or more shafts. The screw conveyor 12 is provided with a screw shaft 13 and blades 14. This screw conveyor 12 can also be composed of only blades 14 without a screw shaft.

The distance between the screw conveyor 12 and the screw feeder 3 is indicated as a. This distance a can be determined based on various conditions such as the amount of stored material and the properties of the stored material, and the position of the screw conveyor 12 is determined so that the direct pressure of the stored material is not applied to the screw feeder 3.

A drive motor 15 is a drive source for rotating the screw conveyor 12 .
The rotation of the drive motor 6 and the drive motor 15 can be controlled by an inverter or a transmission.
Reference numeral 16 denotes a drive chain wheel, which receives drive from a drive motor 15 and transmits power to a drive shaft 18 supported by a drive shaft side bearing 17, thereby rotating the screw conveyor 12. The screw conveyor 12 is held by a driven shaft 20 supported by a driven shaft side bearing 19.

21 is a discharge port, which is located at the end of the trough 2 and allows the accumulated material to be discharged. 22 is a casing that is provided to surround one end of the screw conveyor 12. 23 is a discharge port, which is located at the end of the casing 22 and allows the accumulated material to be discharged. 24 is the accumulated material. The arrows shown in the figure indicate the flow of the accumulated material. In this embodiment, the accumulated material is discharged by combining the discharge ports 21 and 23.

Figure 2 is a cross-sectional explanatory diagram of the screw feeder of the present invention. It shows a hopper 1, a stored material 24, a screw feeder 3, and a screw conveyor 12. In this case, two screw feeders 3 are provided, and one screw conveyor 12 is provided.

In this embodiment, two screw feeders 3 are provided, and these two screw feeders can be adjusted as needed, for example, by using a drive motor with an inverter or a transmission, so that they can be operated synchronously, only one of them can be operated, or only one can be rotated in the opposite direction.

In addition, by using an inverter or a transmission, it is possible to measure the resistance, load, rotation torque, etc. of each of the two-shaft screw feeders and screw conveyors, making it possible to identify where the transported goods are jammed.

Based on this finding, by rotating only a portion of the screw feeder or rotating a portion in the opposite direction, even if the screw feeder becomes clogged with transported material, the clog can be cleared, and maintenance and operational malfunctions can be eliminated.

FIG. 3 shows a screw feeder configured so that the accumulated material discharged from a discharge port provided at the end of the casing 22 can be merged with the trough 2 and can be discharged from a discharge port provided at the end of the trough 2.
When the screw feeder is long, it is effective to merge the discharge port of the screw conveyor into the trough 2.

In this case, the accumulated material is allowed to join the trough 2 from the discharge outlet 25 provided at the end of the casing 22, and can be discharged from the discharge outlet 26 provided at the end of the trough 2. In this case, the accumulated material from the discharge outlet 25 is combined and discharged from the discharge outlet 26, making it easy to adjust and manage the amount of discharge from the discharge outlet 26. This is convenient when specifying a fixed amount of discharge.

In addition, the spacing between the blades of screw feeder 3 at b is increased to allow the accumulated material discharged from the discharge outlet of the screw conveyor to smoothly merge with the screw feeder.

FIG. 4 shows another embodiment of the present invention.
In a hopper 28 for storing the stored material 27, a trough 29 is provided under the hopper 28, and a single-shaft or multiple-shaft screw feeder 30 is installed inside the trough 29. The screw feeder 30 is supported by a driving shaft side bearing 31 and a driven shaft side bearing 32, transmits power from a driving motor 33 to a driving chain wheel 34, and is composed of a driving shaft 35 that rotates the screw feeder 30 and a driven shaft 36 that supports the rotation. The stored material 27 can be discharged from a discharge port 37 provided at the end of the trough 29. A single-shaft or multiple-shaft screw conveyor 38 is installed on the upper part of the screw feeder 30, the screw conveyor 38 is supported by a drive shaft side bearing 39, and is composed of a drive shaft 42 that transmits power from a drive motor 40 to a drive chain wheel 41 and rotates the screw conveyor 38. A plate 44 is provided to support the blades 43 of the screw conveyor 38, and one end of the screw conveyor 38 is surrounded by a casing 45, making it a screw feeder that can discharge accumulated material from a discharge outlet 46 provided at the end of the casing 45.

This alternative embodiment is effective when the hopper 28 is small and the screw conveyor 38 can be made short.
Reference numeral 44 denotes a plate that supports the blades. In the present embodiment, since there is no support for the driven shaft, it is effective to provide two bearings 39 on the driving shaft side. In addition, by providing a plate 44 that supports the blades 43, the screw conveyor 38 can rotate stably.

Figure 5 shows a case where four screw feeders 3 and two screw conveyors are installed. The number of screw feeders and screw conveyors is not limited to these numbers, and can be determined based on various conditions such as the amount of stored material and the properties of the stored material.

Moreover, the screw feeder and the screw conveyor can be operated independently of each other, or can be operated synchronously.
In some cases, these screw feeders and screw conveyors may be rotated separately, or only some of the screw feeders may be rotated at high speed, or if the transported material becomes clogged, some of the screw feeders may be rotated in the opposite direction to clear the clog.

The screw feeder and screw conveyor are configured with a screw shaft and blades. The spacing between the blades can be adjusted as appropriate during the design stage. In the case of a screw feeder, the spacing between the blades can also be varied in different parts. Adjusting the spacing can make it possible to transport the stored material more smoothly. Once the material has passed the screw feeder section (below the hopper), the pitch can be increased.
Furthermore, the size of the screw shaft, the size of the blades, the spacing between the blades, etc. can be adjusted as appropriate.

Some screw conveyors do not have a screw shaft and are composed only of blades. In this case, the lack of a screw shaft allows for a larger conveying volume. The size of the blades, as well as the spacing and direction of the blades, can be adjusted as appropriate.

Figure 6 shows the cross section of a screw conveyor. The screw conveyor is installed in the middle of the hopper, and as shown in the figure, there is no trough or case, so the same pressure is applied from all sides, and direct pressure on one side can be ignored, allowing for smooth rotation.

Figure 7 is an explanatory diagram of a screw feeder equipped with a conventional direct pressure prevention plate. Also, Figure 8 is a cross-sectional explanatory diagram of a screw feeder equipped with a conventional direct pressure prevention plate.

47 is a hopper, 48 is the stored material, 49 is a screw feeder, and 50 is a direct pressure prevention plate. This direct pressure prevention plate 50 is provided to prevent the direct pressure of the stored material 48 from being applied to the screw feeder 49, but in particular when the stored material is very viscous, a bridge can form between the direct pressure prevention plate 50 and the side of the hopper 47, preventing the stored material 48 from reaching the screw feeder 49 below.

The present invention provides a screw conveyor to prevent direct pressure from being applied to the screw feeder.

1 Hopper 2 Trough 3 Screw feeder 4 Screw shaft 5 Blade 6 Drive motor 7 Drive chain wheel 8 Drive shaft side bearing 9 Drive shaft 10 Driven shaft side bearing 11 Driven shaft 12 Screw conveyor 13 Screw shaft 14 Blade 15 Drive motor 16 Drive chain wheel 17 Bearing 18 Drive shaft 19 Driven shaft side bearing 20 Driven shaft 21 Discharge port 22 Casing 23 Discharge port 24 Retention material 25 Discharge port 26 Discharge port 27 Retention material 28 Hopper 29 Trough 30 Screw feeder 31 Drive shaft side bearing 32 Driven shaft side bearing 33 Drive motor 34 Drive chain wheel 35 Drive shaft 36 Driven shaft 37 Discharge port 38 Screw conveyor 39 Drive shaft side bearing 40 Drive motor 41 Drive chain wheel 42 Drive shaft 43 Blade 44 Plate 45 Casing 46 Discharge port 47 Hopper 48 Retention material 49 Screw feeder 50 Direct pressure prevention plate

Claims (4)

In a hopper for storing a retentate, a trough is provided at the bottom of the hopper, and a single-shaft or multiple-shaft screw feeder is installed inside the trough;
The screw feeder is supported by a driving shaft side bearing and a driven shaft side bearing, transmits power from a driving motor to a driving chain wheel, and is composed of a driving shaft that rotates the screw feeder and a driven shaft that supports the rotation. The accumulated material can be discharged from a discharge port provided at the end of the trough.
A single-shaft or multiple-shaft screw conveyor is installed above the screw feeder, spaced apart from the screw feeder, and at a central position in the vertical direction of the hopper ;
The screw conveyor is supported by a driving shaft side bearing and a driven shaft side bearing, transmits power from a drive motor to a drive chain wheel, and is composed of a driving shaft that rotates the screw conveyor and a driven shaft that supports the rotation. One end of the screw conveyor is surrounded by a casing, and accumulated material can be discharged from a discharge outlet provided at the end of the casing. The screw feeder according to claim 1, in which the accumulated material discharged from a discharge port provided at the end of the casing can be merged with the trough and discharged from a discharge port provided at the end of the trough. The screw feeder according to claim 1, characterized in that the accumulated material discharged from the discharge port provided at the end of the casing is merged midway through the trough, and the spacing between the blades of the screw feeder at the merger position is increased. In a hopper for storing a retentate, a trough is provided at the bottom of the hopper, and a single-shaft or multiple-shaft screw feeder is installed inside the trough;
The screw feeder is supported by a driving shaft side bearing and a driven shaft side bearing, transmits power from a driving motor to a driving chain wheel, and is composed of a driving shaft that rotates the screw feeder and a driven shaft that supports the rotation. The accumulated material can be discharged from a discharge port provided at the end of the trough.
A single-shaft or multiple-shaft screw conveyor is installed on the upper portion of the screw feeder,
The screw conveyor is supported only by a drive shaft side bearing, and is composed of a drive shaft that transmits power from a drive motor to a drive chain wheel and rotates the screw conveyor. A plate is provided to support the blades of the screw conveyor. One end of the screw conveyor is surrounded by a casing, and accumulated material can be discharged from a discharge outlet provided at the end of the casing.

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