JPH0298502A - Transportation of powder and apparatus therefor - Google Patents

Abstract

PURPOSE:To prevent a powder from being stirred up and its transport speed from decreasing by setting limit to the closed transport space of the powder and causing the circulation of air from downstream to upstream when viewed in the powder transport direction while simultaneously mixing the powder with the air as required to thereby move the powder from upstream to downstream. CONSTITUTION:The upper parts of a weighing bucket 14 and a hopper tank 11 are in communication with each other through pipes 24 and 25. As powder in the bucket 14 is moved down into a filling nozzle 16, the inner pressure of the upper part of the bucket 14 tends to become lower than that of the filling nozzle 16. This pressure difference creates a circulation of air flow 26 in a first circulating cylindrical member 21 from the bottom to the top, which, in turn, produces a stream of air at a high speed near the lower part of the cylindrical member 21, thereby enhancing the fluidity of the powder in the vicinity thereof. Therefore, the powder is dropped down into the filling nozzle 16, while being mixed with the air near the lower part of the cylindrical member 21 due to the circulation of the air flow.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for transferring powder and an apparatus for transferring powder. In particular, the present invention relates to a method and apparatus that can be effectively applied to start-up and batch transfers of powder in continuous transfers.

[Prior art]

There are many examples, including in the food industry, where powder products are measured into small portions, filled into bags or containers, packaged, and distributed. Powder transportation is essential for filling and packaging the powder. Automatic weighing and automatic filling are of course economically advantageous for industrially packaging small portions of powder, but with this automation comes the problem of dusting of the powder.

FIG. 1 shows the most common conventional automatic weighing and filling device, in which a powder cutting device 2 is provided at the lower end of a hopper tank 1 for storing powder. This cut-out device 2 is usually constituted by a screw type extruder, vibrating type, or Matsue type extruder, and is activated by a signal from a control device 5 to send the powder in the hopper tank 1 downward.

A measuring bucket 4 is provided below the cutting device 2 of the hopper tank 1, and the powder sent out from the hopper tank 1 by the cutting device 2 is stored in the measuring bucket 4. The weighing bucket 4 has a discharge gate 4 that can be opened and closed at its lower end.
A is provided.

Furthermore, the measuring bucket 4 is provided with a measuring device 3, which sends a measuring signal to a control device when a predetermined amount of powder is delivered into the bucket 4, and causes the control device 5 to generate a sending stop signal. . At the same time, the discharge gate 4a of the bucket 4 is opened, and the powder in the bucket 4 is discharged downward.

A filling nozzle 6 is arranged below the metering bucket 4 and is configured to receive the powder discharged from the bucket 4 . The filling nozzle 6 has a downwardly extending hood 8 on the outside of its lower part, and a container or bag 7 to be filled with powder is arranged below the filling nozzle 6. In the configuration of this conventional weighing and filling device, the upper part of the weighing bucket 4, the upper part of the filling nozzle 6, and between the hood 8 and the bag 7 are open to the surroundings, and the openings are shown by arrows a, b, and c. The powder becomes dusty and scatters. Conventionally, as shown in FIG. 1, a suction pipe 9 having a blower 10 is attached to a hood 8 and a filling nozzle 6 is
The powder near the bottom of the machine was being sucked up. In addition, the cutting device 2 is used to prevent dust from rising from the upper part of the measuring bucket 4 and the filling nozzle 6 shown as a and b in FIG.
A large blower is used to surround the area from the filling nozzle 6 to the filling nozzle 6, and to suck up the powder. but,
These conventional measures have not been able to obtain sufficiently satisfactory results, and the container or bag 7 is contaminated by the scattered powder, and the powder enters the sealing surface of the container or bag 7, resulting in poor sealing. The problem is that it damages the. Furthermore, the scattered powder gets into every corner of the device, impeding the operation of the device and causing a decrease in operability. In addition, if the powder becomes very fine, the dusting will become more intense, and the amount of suction by the blower will also increase, resulting in the amount of powder discharged from the blower reaching several percent of the measured value. It becomes a problem.

In order to solve this problem, it is conceivable to make the powder transfer path a sealed system, but this sealed powder transfer path causes the problem that the transfer speed decreases. In other words, when the powder transfer space is substantially sealed and the powder is transferred from the upstream side to the downstream side, as the powder moves, a higher pressure is generated on the downstream side of the powder lump than on the upstream side. do.

For this reason, the air on the downstream side tries to escape to the upstream side through the powder mass, but since the transfer space is a closed system, the powder mass cannot expand sufficiently, and the pressure difference is quickly resolved. Not done.

Therefore, the pressure difference between the downstream side and the upstream side is not eliminated, restricting the movement of the powder, and reducing the transfer speed.

[Problem to be solved by the invention]

The present invention solves the problem that the powder transfer speed decreases when the powder transfer space is made into a substantially sealed state in order to prevent dust particles from forming during powder transfer. It is an object of the present invention to provide a method and apparatus for batch-type transfer of powder, which can substantially prevent the above problems and do not reduce the transfer speed of powder.

[Means to solve the problem]

A powder batch transfer method according to the present invention for solving the above problems is to limit a powder transfer space that is substantially closed and includes a powder transfer area, and to limit the transfer space. In order to prevent a decrease in the transfer speed of the powder due to The powder is moved from the upstream side to the downstream side while causing the powder to mix with air.

When the method of the present invention is applied to a powder metering and filling process, a substantially closed powder tube comprising a powder metering bucket and a filling nozzle arranged below the metering bucket. The powder is circulated from the bottom to the top of the metering bucket, from the bottom to the top of the filling nozzle, and from the filling nozzle to the metering bucket. The body is transferred from the weighing bucket to the filling nozzle and discharged from the lower end of the filling nozzle. Further, a substantially closed powder transfer space including a powder filling nozzle and a filling container disposed below the filling nozzle is defined, and air is directed from the filling container toward the filling nozzle. The powder is transferred from the filling nozzle to the filling container while creating circulation.

The powder transfer device according to the present invention is characterized by providing a circulation cylinder member with open upper and lower ends for causing air circulation from the bottom to the top of the transfer space. That is,
The batch transfer device for powder according to the present invention includes a weighing bucket having a discharge port that can be opened and closed downward, and a filling nozzle provided below the weighing bucket and having a filling port at a lower end, the weighing bucket has a configuration in which a circulation cylinder member is disposed that rises upward from near the discharge port and has open upper and lower ends. Further, an apparatus according to another aspect of the present invention includes a measuring bucket having a discharge port that can be opened and closed downward, and a filling nozzle provided below the measuring bucket and having a filling port at a lower end, the filling nozzle The apparatus is characterized in that a circulation cylinder member is disposed that rises upward from near the filling port to below the discharge port of the measuring bucket and has open upper and lower ends.

[For production]

In the method of the invention, the powder transfer area is substantially closed. When the transfer area is closed in this way, a pressure difference is created between the upstream and downstream sides in the transfer direction across the mass of powder to be transferred, and this pressure difference suppresses the movement of the powder. Work like you do. However, in the present invention, air circulation is generated and the powder is moved from the downstream side to the upstream side when viewed in the powder transfer direction, so the pressure difference between the upstream side and the downstream side is eliminated. The problem of suppressing the movement of powder is eliminated. Furthermore, by moving the powder while causing mixing of the powder and air by circulating air from the downstream side to the upstream side,
The flowability of the powder is increased, further improving transport.

In the transfer device of the present invention, the circulation cylinder member with open upper and lower ends is disposed between the upstream side and the downstream side when viewed in the powder transfer direction, so that the pressure on the downstream side is reduced to the upstream side. When the pressure becomes higher than , air flows from the downstream side to the upstream side, working to eliminate or alleviate the pressure difference. At the same time, the air flow that is about to flow into the circulation cylinder member causes a mixing action between the powder and the air, thereby increasing the fluidity of the powder. Therefore, the problem that the movement of powder is suppressed by the pressure difference between the upstream side and the downstream side is solved, and the transfer of the powder is improved due to the increased fluidity of the powder.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIG. 2, the powder weighing and filling apparatus embodying the present invention has a hopper tank 11 with a powder supply cylinder 11a provided at the top, and a screw-type cut-out device at the lower end of the hopper tank 11. 12 are placed. The hopper tank 11 has a closed top. A weighing bucket 14 is disposed below the hopper tank 11 and is provided with a discharge gage 14a that can be opened and closed at its lower end. The measuring bucket 14 is provided with a measuring device 13, which generates a measuring signal when a predetermined amount of powder is delivered into the measuring bucket 14. The control device 1 is connected to the output of the measuring device 13.
5 is connected, and the control device 15 controls the operation of the cutting device 12.

A filling nozzle 16 is arranged below the metering bucket 14. This filling nozzle 16 surrounds the metering bucket 14 and is closed at the top above the metering bucket 14 . Although the upper part of the filling nozzle 16 and the measuring bucket 14 may be completely sealed, even if there is a slight gap as shown in the figure, there is almost no effect on the operation. The lower part of the filling nozzle 16 is concave downward, and a filling opening 16a is formed at the lower end. On the outside of the filling nozzle 16,
A hood 18 having a shape that expands downward is provided at a position above the filling port 16a.

A bag 17 is attached to the hood 18 as a container filled with powder.

Inside the weighing bucket 14, a first circulation cylinder member 21 is provided that rises upward to the top of the bucket 14 from near the discharge port formed when the discharge gate 14a is opened. The first circulation cylinder member 21 has an open upper end and a lower end. A filling port 1 is provided inside the filling nozzle 16.
From the vicinity of 6a upwards, the discharge gate of the weighing bucket 14)
A second circulation cylinder member 22 that rises up to the vicinity of 14a is provided. This second circulation cylinder member 22 also has an open upper end and a lower end.

A pipe 19 for air circulation, one end of which opens into the inside of the hood 18, is attached to the hood 18.

The other end of the pipe 19 is connected to a switching valve 23. The switching valve 23 is connected on the one hand to the upper part of the metering bucket 14 via a pipe 24 and on the other hand to the upper part of the hopper tank 11 via a pipe 25. The switching valve 23 connects the pipe 19 to the pipe 24 in one switching position and the pipe 24 to the pipe 25 in the other switching position.

Next, the operation of this measuring and filling device will be explained. First, when sending powder from the hopper tank 11 to the measuring bucket 14, operate the switching valve 23 to transfer the powder to the pipe 2.
4 to the pipe 25, the upper part of the hopper tank 11 and the upper part of the measuring bucket 14 are brought into communication. Here, the cutting device 12 is operated to send the powder in the hopper tank 11 to the measuring bucket 14. At this time, the hopper tank 11 and the weighing bucket 14 are each closed, so as the powder is transferred, a relieved pressure is generated in the hopper tank 11 and a positive pressure is generated in the weighing bucket 14. However, in the structure of this embodiment, the upper part of the weighing bucket 14 and the upper part of the hopper tank 11 are in communication with each other via the pipes 24 and 25, so the weighing bucket 14
An air flow from the top of the weighing bucket 14 toward the top of the hopper tank 11 is generated between the top of the weighing bucket 14 and the top of the hopper tank 11 to eliminate the differential pressure between the top of the weighing bucket 14 and the top of the hopper tank 11. ease. As a result, the powder is delivered from the hopper tank 11 to the metering bucket 14 without being inhibited by the pressure difference between the two.

When a predetermined amount of powder is supplied to the weighing bucket 14, a control signal is issued from the control device 15 to control the cutting device 12.
operation is stopped, and at the same time the discharge gate 14a of the weighing bucket 14 is opened. At this time, the switching valve 23
can be switched to the position where it is connected to the pipe 24. discharge game)
When 14a is opened, the powder in bucket 14 is transferred to filling nozzle 16. As the powder in the bucket 14 is transferred to the filling nozzle 16, the air pressure above the bucket 14 tends to be lower than the air pressure inside the filling nozzle 16. Due to this pressure difference, a circulation flow 26 from the bottom to the top is generated in the first circulation cylinder member 21, as shown in FIG. This circulation flow 26 acts to generate a high-speed airflow near the lower end of the first circulation cylinder member 21, thereby increasing the fluidity of the powder in the vicinity. Therefore, in the vicinity of the lower end of the first circulation cylinder member 21, the powder falls downward toward the filling nozzle 16 while the powder and air are mixed by this circulating flow. The upward circulation flow generated within the first circulation cylinder member 21 eliminates the pressure difference between the pressure above the bucket 14 and the pressure inside the filling nozzle 16, and increases the fluidity of the powder. The body moves into the filling nozzle 16 without being inhibited from moving 1 by the differential pressure.

The powder moves downward inside the filling nozzle 16 and enters the filling port 16a.
During this time, a difference in air pressure is created between the upper and lower parts of the filling nozzle 16. However, since the second circulation cylinder member 22 is disposed inside the filling nozzle 16, a circulation flow 27 is generated from the bottom to the top in the second circulation cylinder member 22 due to this pressure difference. This circulating flow 27 eliminates the pressure difference within the filling nozzle 16, and the downward movement of the powder is no longer inhibited by the pressure difference within the filling nozzle 16. In this way, the powder is transferred to the filling nozzle 1
6 to the bag 17. At this time, the pressure generated in the bag 17 escapes from the pipe 19 through the valve 23 and the pipe 24 to the upper part of the measuring bucket 14, so there is a space between the bag 17 and the filling nozzle 16 to suppress the movement of powder. No pressure will be created.

In the embodiment shown in the figure, the moving speed of the powder is higher near the second circulation cylinder member 22 than near the first circulation cylinder member 21. Therefore, it is preferable that the diameter of the second circulation cylinder member 22 is approximately 20 to 50% larger than the diameter of the first circulation cylinder member 21.

Since the powder is mixed with air and in a fluid state in the filling nozzle 16, it is desirable to sufficiently separate the powder from the air before filling the bag 17. For this purpose,
It is preferable that the shape of the lower part of the filling nozzle 16 is formed such that, in a vertical section, the horizontal component of the tangent to the inner surface curve decreases as it approaches the filling opening 16a of the filling nozzle 16. As this curve, as shown in FIG.
An exponential curve represented by 'e' may be used. In the filling nozzle 16 configured by this curve, a horizontal inward force as shown by an arrow 29 acts on the powder 28 at a position above the filling port 16a of the filling nozzle 16, and this action causes the powder to The body is compressed, but this compressive action gradually weakens as it goes downward, until the filling port 16a
There is almost no compressive force in the vicinity of , and only the vertical falling blade acts on the powder, causing the powder to fall smoothly into the bag 17.

〔effect〕

As described above, in the present invention, when transferring powder, the transfer space including the powder transfer area is substantially closed, so that the powder does not scatter outside the transfer area.

In addition, in the transfer space, the powder is moved from the upstream side to the downstream side while causing air circulation from the downstream side to the upstream side, so the difference between the upstream side and the downstream side that occurs as the powder moves The movement of the powder is not inhibited by the pressure difference between the two, allowing efficient transfer. Furthermore, if the powder and air are mixed with each other as the air circulates, the fluidity of the powder will be increased and transfer can be achieved more efficiently.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a schematic sectional view of a conventional powder measuring and filling device, and Fig. 2 is a schematic sectional view of a powder measuring and filling device showing an embodiment of the present invention. FIG. 3 is an enlarged sectional view of a metering bucket to show the effect of the present invention, and FIG. 4 is a sectional view showing a preferred shape of the filling nozzle. 11... Hopper tank, 12... Cutting device, 14... Measuring bucket, 14a... Discharge gate, 16... Filling nozzle, 17... ... Bag, 18 ... Hood, 21 ... First circulation cylinder member, 22 ... Second circulation cylinder member.

Claims (13)

[Claims] (1) A substantially closed powder transfer space including a powder transfer area is limited, and air is circulated from the downstream side to the upstream side when viewed in the powder transfer direction within the space. A method for transferring powder, characterized in that the powder is moved from an upstream side to a downstream side while causing. (2) A method for transferring powder according to claim 1, characterized in that mixing of the powder and air is caused by circulation of the air. (3) defining a substantially closed powder transfer space including a powder measuring bucket and a filling nozzle disposed below the measuring bucket, from the bottom to the top of the measuring bucket; From the bottom to the top of the filling nozzle,
Further, from the filling nozzle to the measuring bucket,
A batch transfer method for powder, characterized in that the powder is transferred from the metering bucket to the filling nozzle while creating air circulation, and is discharged from the lower end of the filling nozzle. (4) A substantially closed powder transfer space including a powder filling nozzle and a filling container disposed below the filling nozzle is defined, and air is directed from the filling container toward the filling nozzle. A batch transfer method for powder, characterized in that the powder is transferred from the filling nozzle to the filling container while causing circulation. (5) In the transfer method according to claim 4, the filling container is a flexible bag, and the powder is transferred with the bag deflated in advance. Batch transfer method. (6) Defining a substantially closed powder transfer space including a powder measuring bucket, a filling nozzle disposed below the measuring bucket, and a filling container disposed below the filling nozzle; , the powder is removed from the metering bucket while causing air circulation from the bottom to the top of the metering bucket, from the bottom to the top of the filling nozzle, and from the filling nozzle to the metering bucket. The powder is transferred to the filling nozzle, and the powder is further transferred from the filling nozzle to the filling container while causing air circulation from the filling container to the upper part of the measuring bucket. Batch transfer method. (7) A measuring bucket having a discharge port that can be opened and closed downward, and a filling nozzle provided below the measuring bucket and having a filling port at a lower end, and the measuring bucket has a filling nozzle provided below the measuring bucket from the vicinity of the discharge port upwardly. 1. A batch transfer device for powder, characterized in that a circulation cylinder member that stands upright and is open at its upper and lower ends is disposed. (8) A weighing bucket having a discharge port that can be opened and closed downward, and a filling nozzle provided below the weighing bucket and having a filling port at a lower end, and the filling nozzle is provided with a filling port from the vicinity of the filling port. A batch transfer device for powder, characterized in that a circulation cylinder member is disposed that rises upward to below the discharge port of the bucket and is open at its upper and lower ends. (9) In the device according to claim 7, a second circulation cylinder member is disposed in the filling nozzle and extends upward from near the filling port to below the discharge port of the measuring bucket and has an open upper end and a lower end. A batch transfer device for powder, which is characterized by: (10) In the device according to any one of claims 7 to 9, the filling nozzle has a shape in which, in a vertical cross section, a horizontal component of a tangent at each point on the inner surface of the filling nozzle decreases as it approaches the filling port. A batch transfer device for powder, characterized in that: (11) In the apparatus according to any one of claims 7 to 10, a downwardly expanding hood for attaching a powder filling container is provided outside the lower part of the filling nozzle, and the inside of the hood is A batch transfer device for powder, characterized in that a circulation path connected to the upper part of a bucket is formed. (12) The apparatus according to claim 11, wherein the circulation path is provided with a switching valve. (13) a first powder container having a discharge port at the bottom and a closed top; and a first powder container having a closed top and communicating with the discharge port of the first powder container. a second powder container disposed below the powder container;
The powder container is provided with a circulation cylinder member whose top and bottom ends are open, rising upward from near the discharge port and reaching the top of the first powder container.
Powder transfer device.