JPH109929A - Constant-quantity feeding device of paticfulate and powdery element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device which quantifies and feeds particulate and powdery elements with higher accuracy than ever and a minimum measurement error through the use of changes in suction force in a storage hopper. SOLUTION: Particulate and powdery bodies in a storage tank 1 are sent into a storage hopper 10 via a supply pipe 3, and the insertion level of a measurement regulating pipe 13 in the hopper is regulated to a predetermined level. When the piling particulate and powdery bodies block the lower end of the measurement regulating pipe 13, suction force changes. This change in the suction force is detected by a pressure sensor to quantify. Then the particulate and powdery bodies are supplied downwards by opening a shutter 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quantitative measuring device for measuring the amount of a granular material and a quantitative supplying device for quantitatively supplying a granular material using the device.

[0002]

2. Description of the Related Art When a raw material is supplied to a mold for molding a synthetic resin product, a pellet-shaped raw material is generally used. The raw material powder is stored in a tank, and when used, a fixed amount required for the mold is measured and sent into the mold by a screw conveyor or the like. A device disclosed in Japanese Utility Model Publication No. 60-15129 is known as a device for measuring a granular material used for such a purpose.

In the weighing device according to this publication, an automatic opening / closing lid is provided at the lower end of a weighing hopper, the upper end of the hopper is closed with a lid plate, and a suction pipe is connected to the lid plate so that suction can be performed with a suction pump. An opening is provided, and the opening at the lower end of the storage tank that stores the powder and granules is connected by a connection pipe. A weighing rod is provided at the center of the weighing hopper through the upper lid plate so as to adjust the weighing level. At the lower end of the weighing rod, a detection sensor for detecting the level of the granular material stored in the hopper is provided. Is provided.

Normally, the opening / closing lid at the lower end of the hopper is closed, and when the suction pump is started, the powder or granular material in the storage tank is sucked and moved to the weighing hopper. Will be stored. When the storage level rises, the detection sensor detects that a predetermined amount has been stored, stops the suction of the suction pump by the detection signal, and opens the lower end opening / closing lid to measure the predetermined amount to the lower screw conveyor. Is dropped.

[0005]

Incidentally, the above-mentioned conventional granular material supply apparatus can measure and supply a fixed amount by detecting a predetermined storage level by a detection sensor. As this detection sensor, for example, an optical sensor or the like cannot be used due to the storage form of the granular material (it malfunctions with fine particles), and although not explicitly shown, a capacitance type sensor is actually used. .

However, even when the capacitance type detection sensor is used, the particles are charged with static electricity due to frictional collision between the particles when the particles are transferred from the storage tank. The detection accuracy of the storage level is poor, and as a result, the error of the storage amount becomes as much as 20 to 30%.

Further, a filter is provided horizontally below the lid plate above the storage hopper so as to prevent the particles from reaching the suction pump when the particles are sucked by the suction pump. . However, since the horizontal filter is easily clogged, a rotary air cleaning member is provided between the cover plate and the filter, and the filter can be cleaned by rotating with a motor on the cover plate. .

For this reason, the structure of the cleaning apparatus is complicated, the cost is increased, and the cleaning must be performed periodically.

The present invention takes into account the problems of the above-mentioned conventional granular material supply apparatus, and stores the amount of the granular material without detecting the storage level of the granular material stored in the storage hopper with a detection sensor. It is an object of the present invention to provide an inexpensive powdery / granular material supply device having a structure capable of accurately measuring with high precision, preventing clogging of a filter, and requiring little time for filter cleaning.

[0010]

According to the present invention, as a means for solving the above-mentioned problems, an openable / closable lid is provided at a lower end of a storage hopper for storing and quantifying powdery granules, and the inside of the storage hopper is doubled. A vertical filter provided with a number of small holes in the partitioning plate is provided in the hopper, the upper end is closed with a lid plate, connected to a supply pipe that guides the powder from the storage tank, and the level can be adjusted through the upper lid plate An operation control unit that inserts the metering adjustment tube into the hopper, provides a suction tube connected to the suction pump on the outer periphery of the storage hopper, and controls the suction pump with a signal from a pressure sensor that detects the internal pressure of the storage hopper; By driving the suction pump at a pressure equal to or less than the hopper internal pressure set in advance, the powder is sucked and transferred from the storage tank by the suction pressure, and the lower end of the metering adjustment pipe set at a predetermined level is closed with the stored powder. By being When the suction pressure rises at the set pressure by detecting these weighing the quantitative powder and granular material, it was a granule dispensing apparatus comprising as quantitatively supplying granular material.

[0011] According to the above-structured powder / particle quantitative supply apparatus, the suction pressure of the suction pump is not more than a predetermined pressure, and the powder / particle is sucked and transferred from the storage tank to the storage hopper via the supply pipe. When the stored powdered material rises and rises slightly above the lower end of the metering adjustment tube, the suction pressure changes because the lower end is blocked by the powdered material.

When the increased suction pressure reaches the set pressure, the suction pump is stopped, the transfer of the granules is stopped, and the granules stored up to that time are supplied by opening the lower end lid as a fixed amount. . For the quantitative determination of the above-mentioned granular material, if the measured value is displayed in advance on the measuring and adjusting tube, by moving the measuring and adjusting tube up and down to the required amount and setting it, the quantitative amount of the granular material is measured with extremely high accuracy. .

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an overall schematic system of the powder and granular material fixed supply system. In the figure, B is a granular material supply device, and A is a storage unit for granular materials. In the storage tank 1 of the granular material storage section A, the pellet-like granular material (2-3
mm synthetic resin material is stored in large quantities,
A required amount of the granular material is transferred by a supply pipe 3 connected to a collection pipe 2 inserted into the storage tank 1. The supply pipe 3 uses a rubber hose. 4 is a secondary air control hole.

The powdery and granular material supply apparatus B includes a storage hopper 10
It has. The storage hopper 10, as shown in FIG.
The lower end is closed by a shutter 11 that can be opened and closed, and the upper part is closed by a lid plate 12. A metering adjustment tube 13 is inserted into the hopper through the upper lid plate 12 so that the level can be adjusted. A vertical filter 14 that divides the inside of the hopper doubly is provided in the storage hopper 10, and a suction pipe 15 that absorbs the inside of the hopper is provided on the outer periphery of the hopper. Further, a control unit 16 is provided outside the hopper. S is a pressure sensor for detecting the suction pressure in the hopper. The lower end of the storage hopper 10 is connected to a discharge pipe 17, and the discharge pipe 17 is connected to a screw conveyor C to supply the raw material to the mold D.

The shutter 11 can be opened and closed by operating a shutter plate 11a by a piston 19 of a cylinder 18 and selecting an opening and a closing portion provided on the shutter plate 11a. The cover plate 12 is closed by a patch lock 20 (a plurality of places) shown in FIG.
The metering adjustment tube 13 is vertically movable by a nut 21 screwed to a screw provided on the outer periphery thereof so that the level can be adjusted, and the above-described supply tube 3 is connected to the upper end thereof.
A scale (not shown) is provided outside the metering adjustment tube 13, and the pointer 22 is fixed on the cover plate 12.

The cylindrical vertical filter 14 that partitions the inside of the storage hopper 10 has an upper end in contact with the lid plate 12 and a lower end in contact with the hopper inclined portion, thereby separating the inside and the outside of the vertical filter 14. A large number of small holes 14a are provided in the wall surface of the filter 14. The small holes 14a are perforated to a size that does not allow the passage of powder (2 to 3 mm in diameter). Since the vertical filter 14 has a cylindrical peripheral wall provided vertically, even if the granular material sucked by the suction pressure collides with the peripheral wall, it cannot pass through the small hole 14a, and falls along the vertical wall, Therefore, no clogging occurs even if there is no filter clogging removing device.

As shown in FIG. 1, a suction pump 24 is connected to the suction pipe 15 via another fine secondary filter 23, and is driven by a motor 25.
As shown in FIG. 4, the control unit 16 that controls the motor 25 receives a pressure detection signal from the pressure sensor S that detects the suction pressure in the storage hopper 10, and is set in advance by the setting unit 26 and set on the display 28. , The output to the motor 25 is stopped and the output signal is sent to the solenoid valve 29 when the suction pressure reaches the set pressure.
Is operated to discharge the granular material in the storage hopper 10.

When the granular material is sucked and transferred by the suction pump 24, the granular material itself passes through the vertical filter 14 only when the diameter of the small hole of the vertical filter 14 is smaller than the granular material. However, since it is not possible to prevent the powders from colliding or rubbing with each other during the transfer and becoming fine powders, these fine powders are removed by the secondary filter 23. .

The powder is supplied after the quantitative measurement of the powder is measured as follows by the powder and particle quantitative supply system of the embodiment having the above-described configuration. Shutter 1 at bottom of empty storage hopper 10
In a state in which the suction pump 1 is closed, the target set pressure of the suction pressure is set by the setter 26 of the control unit 16, displayed on the display 28, the suction pump 24 is started, and the inside of the storage hopper 10 is set to a negative pressure to thereby control the powder. The granular material is transferred from the granular material storage tank 1 via the supply pipe 3.

Before the transfer is started, the level is adjusted in advance so that the lower end of the metering adjustment tube 13 is positioned at a predetermined level in the storage hopper 10 so that the stored amount can be measured. The storage amount is measured in advance for each set level, and the scale on the outer periphery of the metering adjustment tube 13 is adjusted to a predetermined level with respect to the indicator needle 22.

When the transfer of the granular material is started by the suction pump, the granular material is deposited in the storage hopper 10, and the storage level rises. When it is desired to adjust the storage speed, the opening degree of the secondary air adjusting hole 4 at the upper end of the collection pipe 2 may be adjusted. When the storage level of the granular material rises and rises slightly above the lower end of the measuring and adjusting tube 13, the lower end of the measuring and adjusting tube is closed by the granular material, and the suction pressure becomes larger than the suction pressure during transfer.
By utilizing this, it is detected that the granular material has reached a predetermined level.

The change in the suction pressure is determined by comparing the suction pressure signal from the pressure sensor with the target set pressure in the arithmetic and control unit 27, and assuming that when the suction pressure increases to the target set pressure, the granular material reaches a predetermined level. A control signal for stopping the motor 25 of the suction pump 24 is output from the arithmetic control unit 27. A little later or at the same time, a control signal is also sent to the solenoid valve 29 to drive the cylinder 18, and when the shutter 11 is opened, the granular material is discharged from the storage hopper 10 and the screw conveyor C
To the mold D.

According to the experimental results obtained by measuring the storage amount of the granular material of synthetic resin (PP) having a diameter of 3 m / m with the above-mentioned apparatus, the following results were obtained, for example. Target setting (vacuum) pressure Storage amount Accuracy 1st time 70 mmHg 465-474 g 2% 20 61-64 g 2nd 70 mmHg 463-470 g 1.5% 20 60-61 g Indicates that measurement was performed.

The measurement accuracy described above shows a remarkable improvement as compared with the measurement accuracy of the conventional quantitative supply device which directly detects the storage level by the capacitance sensor, which is 20 to 30%. As a result, the accuracy was almost the same not only for the above-mentioned measurement of the synthetic resin but also for various crushed powders. Therefore, in the above-described embodiment, the description has been given on the assumption that the synthetic resin particles (pellets) are quantitatively supplied. However, the granular material quantitative supply apparatus according to the present invention is not limited to the synthetic resin particles, and various types of granular materials may be used. It will be clear that it can be used as a metered supply of material.

However, if the type and particle size of the powders are different from those described above, the small holes 14a of the vertical filter 14 may have different diameters according to the purpose. Further, for example, P.I. P. In the case of an ABS resin having a specific gravity higher than that of (polypropylene), it is preferable to finely adjust the target set pressure to a slightly larger value.

[0026]

As described above in detail, the powdery and granular material supply apparatus of the present invention has the lower portion of the storage hopper closed by the opening / closing lid, penetrates the upper lid plate, inserts the metering adjustment tube, and has a vertical filter inside. When the powder is sucked by the suction pipe provided on the peripheral wall, the suction pressure rises when the lower end of the metering adjustment pipe is closed with the powder, and when the set pressure is reached, the pressure sensor detects it and stops the metering suction. By discharging the stored powders and granules, the metering accuracy can be measured within a few% error without the measurement accuracy being greatly disturbed as in the conventional metering device. In addition, the structure is extremely simple, and the clogging removal operation using the filter is simple, and an inexpensive quantitative supply device can be provided.

[Brief description of the drawings]

FIG. 1 is a general schematic system diagram of a powder and granular material fixed supply system according to an embodiment.

FIG. 2 is an outline drawing of a powder and particle quantitative supply device.

FIG. 3 is a sectional view of the above.

FIG. 4 is a block diagram of a control circuit of the device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Storage tank 3 Supply pipe 10 Storage hopper 11 Shutter 12 Cover plate 13 Metering adjustment pipe 14 Vertical filter 15 Suction pipe 16 Control part 18 Cylinder 21 Nut 22 Indicator needle 23 Secondary filter 24 Suction pump 25 Motor 27 Arithmetic control part 28 Display 29 solenoid valve

Claims (2)

[Claims] 1. A vertical filter provided with an openable and closable lid at a lower end of a storage hopper for storing and quantifying powder particles, and having a plurality of small holes formed in a plate that divides the inside of the storage hopper doubly. The upper end is closed with a lid plate, and a metering adjustment tube that is connected to a supply pipe that guides the powder and granular material from the storage tank, penetrates the upper lid plate, and allows level adjustment is inserted into the hopper, and a suction pump is provided around the storage hopper. A suction pipe connected to the storage pump is provided, and an arithmetic control unit that controls the suction pump with a signal from a pressure sensor that detects the internal pressure of the storage hopper is provided, and the suction pump is driven at a pressure equal to or lower than the hopper internal pressure set in advance by the arithmetic control unit. When the suction pressure rises to the set pressure by suctioning and transferring the granular material from the storage tank by the suction pressure and closing the lower end of the metering adjustment tube set at a predetermined level with the stored powder material, these are detected. Measure quantitative powder An apparatus for quantitatively supplying a granular material, which weighs and supplies the granular material. 2. A weighing scale is displayed on the weighing adjustment pipe, and the weighing adjustment pipe is vertically adjusted to set a weighing value in accordance with an indicator provided on a storage hopper. An apparatus for quantitatively supplying a granular material according to claim 1.