JPH04286521A - Screw type feeding device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw-type feeding device for cutting raw materials using a screw.

0002

2. Description of the Related Art A conventional screw type feeding device is constructed as shown in FIGS. 2 and 3. It consists of a hopper 1 into which raw material A is charged, a screw 2 that cuts out the raw material from this hopper 1, a motor 3 that drives the screw 2, and the like. The motor 3 is operated by the motor control section 4 so as to have a constant rotational speed according to the set flow rate value B.

0003

As described above, when the raw material A is cut out by rotating the screw 2 at a constant rate, pulsations occur in the flow of the raw material cut out during one rotation. FIGS. 3(a) and 3(b) show the mechanism of this occurrence.

That is, the portion of the blade 5 of the screw 2 facing the opening edge of the discharge port 6 is located upward.
), the powder raw material A is smoothly discharged as shown by the arrow 7, whereas the part of the screw blade 5 facing the opening edge of the discharge port 6 is located downward (Fig. 3). (b)
In this state, the discharge port 6 is blocked by the screw blade 5, making it difficult for the powder to be discharged. As a result, the amount of powder or granules discharged varies depending on the rotational position of the screw 2, resulting in a problem that accurate quantitative cutting cannot be performed.

However, since the degree of this pulsation varies depending on the properties of the raw material being handled, it is desired to accurately measure the degree of pulsation. SUMMARY OF THE INVENTION An object of the present invention is to provide a screw type supply device that can accurately measure the degree of pulsation and realize highly accurate constant flow dispensing.

[0006]

[Means for Solving the Problems] The screw type feeding device of the present invention is a screw type feeding device that cuts raw materials from a hopper by driving the screw with a motor, and detects the torque transmitted to the drive system of the screw by the motor. The present invention is characterized in that a torque sensor is installed, and the occurrence of pulsation in the flow of the discharged raw material is detected from fluctuations in the torque value detected by the torque sensor.

[0007]

[Operation] According to this configuration, the state in which the screw is conveying the raw material is constant at any angle during one rotation of the screw when pulsation is not occurring,
), the load becomes lighter immediately after a large amount of raw material has flowed out. The torque sensor can measure the state of this transmitted torque and detect the occurrence of pulsation from torque fluctuations. Therefore, when the occurrence of pulsation is detected, highly accurate constant flow dispensing can be realized by controlling to reduce this torque fluctuation.

[0008]

[Embodiment] An embodiment of the present invention will be described below with reference to FIG. Components having the same functions as those in FIG. 2 showing the conventional example will be described with the same reference numerals.

FIG. 1 shows a screw type feeding device of the present invention. A screw 2 that cuts raw material from a hopper 1 is driven by a motor 3, and a torque sensor 8 is interposed between an output shaft 3a of the motor 3 and a shaft 2a of the screw 2. A flow rate setting value B and an occasional torque detection value Cs of the torque sensor 8 are input to the motor control unit 4 .

The motor control unit 4 calculates the deviation between the standard torque value Cr and the occasionally detected torque value Cs while driving the motor 3 so that the screw 2 has a rotational speed D corresponding to the flow rate setting value B. The rotational speed of the motor 3 is corrected so that Cr approaches Cs.

With this configuration, when going from the state shown in FIG. 3(b) to the state shown in FIG. 3(a),
The rotational speed of the motor 3 is corrected to be slower than the previous rotational speed, and pulsation is reduced.

In the above embodiment, the rotational speed of the motor 3 is corrected based on the occasional torque detection value Cs of the torque sensor 8 to reduce pulsation. When the raw material is being cut out while rotating the motor 3 at a constant speed while applying a constant biasing force in the direction of closing the opening of the discharge port 6, the biasing force is adjusted to the detected torque value Cs. If the detected torque value Cs becomes smaller, the biasing force is weakened, and if the detected torque value Cs becomes larger, the biasing force is increased to reduce the pulsation. The same is true.

Furthermore, when raw material is cut out from the hopper 1 using two screws arranged in parallel, a torque sensor 8 is installed in the drive system of at least one of the screws, and when the occurrence of pulsation is detected, It is configured to operate continuously while changing the phase difference between the two screws in a direction to reduce pulsation.

[0014]

As described above, according to the present invention, a torque sensor for detecting the transmitted torque is interposed in the drive system of the screw by the motor, and pulsation is caused in the flow of the discharged raw material due to fluctuations in the torque value detected by the torque sensor. It is possible to detect the occurrence of pulsation, accurately measure the degree of pulsation, and contribute to highly accurate constant flow dispensing.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of a screw type feeding device of the present invention.

FIG. 2 is a configuration diagram of a conventional screw type feeding device.

FIG. 3 is an explanatory diagram of the mechanism of pulsation occurring in the screw-type feeding device.

[Explanation of symbols]

1 Hopper 2 Screw 3 Motor 6 Discharge port 8 Torque sensor

Claims (1)

[Claims] Claim 1: In a screw-type feeding device that cuts raw materials from a hopper by driving a screw with a motor, a torque sensor that detects transmitted torque is interposed in the drive system of the screw by the motor, and the detected torque value of the torque sensor is installed. A screw-type feeding device that detects pulsation in the flow of the discharged raw material from fluctuations in the flow rate.