JPH05266340A - Powder raw materials sending-out device - Google Patents

Abstract

PURPOSE:To provide a powder raw materials sending-out device which can precisely send out powder raw materials in spite of the amount of a remainder. CONSTITUTION:A DC motor 4 whose rotational speed is affected by the size of a load is used for the power source of a screw conveyor 2, and a rotational speed measurement means 3 estimates the apparent density of the powder raw materials which are sent out at present from an ejecting port 11 based on the rotational speed of the screw conveyor 2. Thus, the operation time of the DC motor 4 is corrected. Even if the apparent density of the powder raw materials near the screw conveyor 2 changes by the amount of the powder raw materials in a raw materials container 1, they can precisely be sent out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for accurately delivering powder raw materials.

[0002]

2. Description of the Related Art As an apparatus of this kind, a full-scale model 60-55
The device proposed in Japanese Patent Publication No. 76 is known. The device of the present invention measures the reference signal (reference rotation amount) and the actual rotation amount of the screw conveyor or motor based on the idea that the discharge of the powder raw material can be controlled in proportion to the rotation speed of the screw conveyor. Then, the reference signal and the actual value are compared and calculated, and the operation of the motor is stopped when the two match.

However, this apparatus has the following problems, and even if it is carried out, there is a drawback that an effect commensurate with the input cost cannot be obtained.

That is, when a large amount of powder raw material is contained in the raw material container, the apparent density of the powder raw material in the vicinity of the screw conveyor is high, and conversely, when the raw material is carried out and the residual amount becomes small, the apparent density becomes small. Therefore, when the screw conveyor is controlled at a constant rotation speed, as shown by the broken line in FIG. 3, when the number of discharges increases and the powder raw material in the container decreases, the discharge amount tends to gradually decrease.

For this reason, when such a conventional device is used as a device for discharging coffee raw materials into a cup in, for example, an automatic vending machine, the lower limit value of the amount of discharge required for maintaining the quality of the product is: Since it is usually 90% of the carry-out amount, as shown in the figure, a defective product will be generated long before the powder raw material is completely consumed. In order to prevent the generation of such defective product, the powder raw material is frequently used. There is a problem in that the material must be replenished or if it cannot be replenished frequently, it must be sold out with a large amount of the stored raw material left.

[0006]

Therefore, it has been expected to devise a powder raw material unloading device capable of accurately delivering a predetermined amount of powder raw material without being affected by the remaining amount of the powder raw material. .

[0007]

As a concrete means for solving the above-mentioned problems of the prior art, the present invention carries out the powder raw material by rotating a screw conveyor provided at the bottom of the raw material container with a motor. In the above, a direct current motor whose rotation speed is influenced by the magnitude of the load is used for the motor, the rotation speed of the screw conveyor or the motor is detected, and the operating time of the motor is corrected according to the magnitude of the rotation speed. The present invention provides a powder raw material unloading device for solving the above-mentioned problems of the prior art.

[0008]

[Function] As the powder raw material in the raw material container decreases, the apparent density of the powder raw material in the vicinity of the screw conveyor decreases, and the resistance when the screw conveyor rotates decreases. Although the rotation speed increases, this rotation speed is accurately measured by the rotation speed measuring means, the apparent density of the powder raw material currently being carried out is estimated from this measurement data, and the required operation is performed based on the required weight of the powder raw material. The time is accurately calculated, and the operating time is corrected based on the calculation result. Therefore, the powder raw material is accurately delivered regardless of the amount of the powder raw material.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, 1 is a raw material container, 2 is a screw conveyor, 3 is a rotational speed measuring means, and 4 is a DC motor.

The screw conveyor 2 conveys powder raw material (not shown) along a screw surface to which rotational force is applied by the DC motor 4, and the tip of the powder conveyor is directed toward the carry-out port 11 of the raw material container 1. It is installed horizontally on the inner bottom of the container 1.

The rotation speed measuring means 3 is fixedly attached to the rotation shaft 21 of the screw conveyor 2 so that the rotation speed can be measured. This rotation speed measuring means 3
Photosensor 31 including a pair of light emitting element and light receiving element
Are installed with the peripheral portion of the disk 32 sandwiched therebetween, and the screw conveyor is driven by the number of times the light receiving element receives light from the light emitting elements passing through the through holes 33 provided at a constant pitch on the peripheral portion of the disk 32 in a predetermined time. It measures the rotation speed of No. 2 and sends the measurement data to the control unit.

The raw material detection sensor 12 is used to detect that the raw material container 1 contains a predetermined amount of powder raw material or more.
In this case, the raw material detection sensor 12 is a capacitance type sensor and can detect whether or not there is powder raw material at the height of the sensor mounting position.
If the remaining amount of powder raw material decreases below the mounting position of the raw material sensor 12, there is a concern that the amount of powder raw material carried out may not be the required amount even if the rotation of the screw conveyor 2 is corrected as described below. A signal of "no raw material" is transmitted to the control unit.

Since the apparent density of the raw material in the vicinity of the screw conveyor 2 increases as the amount of the powder raw material remaining in the raw material container 1 increases, the resistance when the screw conveyor 2 rotates increases. Since the apparent density of the raw material is small, the rotation resistance is also small.

For this reason, the DC motor 4 rotates slowly when there is a large amount of powder raw material remaining and has a high apparent density, and the residual amount of powder raw material decreases, the apparent density decreases and the rotation speed increases, so an AC motor is used. Compared with the unloading device described above, the unloading amount of the powder raw material tends to be automatically corrected (during a predetermined time of operation).

However, in order to perform a more complete correction,
The correlation between the apparent density of the powder raw material and the rotation speed of the DC motor 4, for example, the relationship as shown in FIG. 4 is previously obtained by an experiment, and the DC motor 4 is measured by the rotation speed measuring means 3.
The apparent density of the powder material currently carried out from the carry-out port 11 is estimated based on the rotation speed of the, and the required carry-out operation time is calculated from the required weight of the powder material to operate the DC motor 4. The time is corrected.

FIG. 2 is an example of a block diagram for correcting the operating time of the DC motor 4. When the rotation speed of the DC motor 4 measured by the rotation speed measuring means 3 is input to the control unit 5, the control unit is controlled. In 5, the correlation between the apparent density of the powder raw material and the rotation speed of the DC motor 4 (Fig. 4 etc.)
The apparent density of the raw material powder currently unloaded from the unloading port 11 is estimated, the required operating time is calculated from the apparent density and the rotation speed thus obtained, and the correction signal 6 is output to the motor drive unit 7. Is configured to.

In the powder raw material carrying-out apparatus having the above-mentioned structure,
When the powder raw material in the raw material container 1 decreases and the apparent density decreases, the resistance decreases and the rotation of the DC motor 4 (and the screw conveyor 2) increases, so this rotation speed is measured by the rotation speed measuring means 3. Measure and estimate the apparent density of the powder material currently unloaded from the unloading port 11 each time, accurately grasp the unloading amount per hour or per one rotation of the motor, calculate the required operating time, and calculate the DC In order to correct the operation time of the motor 4, regardless of the amount of the powder raw material stored in the raw material container 1, a predetermined amount is exactly delivered to the point just before the raw material powder runs out, as shown by the solid line in FIG.

To explain the specific operation, in the state where the powder raw material is sufficiently contained in the raw material container 1, even if the storage amount of the powder raw material decreases and the apparent density thereof decreases, the DC motor 4 The rotation is delayed by that amount and is automatically corrected, so the above correction by calculation is not performed. Then,
If the amount of powdered raw material falls below the state of being sufficiently stored,
The control unit 5 determines that correction by calculation is necessary.

For example, if the operating time of the DC motor 4 without correction by calculation is 2 seconds, the control unit 5
Calculates the correction time by sampling the rotation speed data from 0.5 second to 1 second after the activation of the DC motor 4 and estimating the apparent density of the powder material currently being carried out from this data.
Then, by adding this correction time to the remaining operation time to prolong the drive time of the DC motor 4, the control unit 5 controls to carry out a required amount of the powder raw material.

In the above structure, the relationship between the rotation speed of the DC motor 4 and the apparent density of the powder raw material (FIG. 4) differs depending on the type of the powder raw material. Therefore, the control unit 5 stores such characteristic data according to the type of the powder raw material stored in the raw material container 1, and the control unit 5 can select the corresponding data when the raw material is changed.

Since the present invention is not limited to the above embodiment, appropriate modifications can be made. For example, the rotational speed measuring means 3 may be configured so that the rotational speed of the screw conveyor 2 or the DC motor 4 can be accurately measured, and thus the mounting position and the configuration thereof can be appropriately changed.

[0022]

As described above, the powder raw material unloading device of the present invention estimates the apparent density of the powder raw material currently being carried out by the screw conveyor from the rotation speed of the DC motor, and based on this, estimates the apparent density of the powder raw material. Since the device corrects the operating time, it is possible to always carry out the powder raw material with high accuracy regardless of the amount of the powder raw material in the raw material container.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment in which a part is broken away.

FIG. 2 is a block diagram showing a control method according to an embodiment.

FIG. 3 is an explanatory view showing a discharge characteristic of a powder raw material.

FIG. 4 is an explanatory diagram showing the relationship between the apparent density of the powder raw material and the rotation speed of the DC motor.

[Explanation of symbols]

 1 Raw Material Container 11 Outgoing Port 2 Screw Conveyor 3 Rotational Speed Measuring Means 31 Photo Sensor 32 Disc 33 Through Hole 4 DC Motor 5 Control Section 6 Correction Signal 7 Motor Drive Section

Claims (1)

[Claims] 1. A screw conveyor provided at the bottom of a raw material container for carrying out powder raw materials by rotating the motor with a motor, wherein a direct current motor whose rotational speed is affected by the magnitude of the load on the motor is used. Alternatively, the powder raw material discharge device is characterized in that the rotation speed of the motor is detected and the operating time of the motor is corrected according to the magnitude of the rotation speed.