JPH02265818A - Device for supplying constant amount of impalpable powder - Google Patents

Abstract

PURPOSE:To prevent the irregular movement of impalpable powder having the average grain size less than a predetermined value in a viration type constant amount supply device by providing a vibration plate with a plurality of apertures in a tube for fluidizing said powder by high frequency vibration and connecting one end of the tube to a hopper so as to form the other end in an outlet. CONSTITUTION:A high frequency vibrator 9 is oscillated by high frequency vibration generated by a high frequency generator 10 to vibrate a fluidizing tube 7 through a vibration transmitting horn 8. Thus, an upper vibration plate 5 is vibrated to fluidize and drop impalpable powder onto a lower vibration plate 6 which also is vibrated so that said powder is fluidized to be discharged by a constant amount. Thus, the impalpable powder having the mean grain size less than about 30mum can be continuously supplied without irregular movement.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a quantitative supply device for powder, and in particular, it relates to
This invention relates to a device for quantitatively feeding fine powder particles of 0 μm or less.

[Prior Art] Conventionally, methods for quantitatively and continuously supplying powder include a rotary table type, a screw type, and a vibrating feeder type.

[Problem H to be solved by the invention] However, all of the above conventional methods are suitable for supplying a large amount of powder with a relatively large particle size, and are not suitable for quantitatively and continuously supplying fine powder with an average particle size of 30 μm or less. Not suitable for supply. This is because the smaller the particle size of the powder, the greater the cohesive force between the powders, making it difficult to stably supply the powder.

In other words, when a certain amount of powder gathers near the supply port and the discharge pressure overcomes the cohesive force between the powders, a large amount of powder will be discharged at once, and the powder supply will be reduced. A phenomenon of ``pulsating'' instead of continuous occurs. This phenomenon becomes more pronounced as the particle size of the powder becomes smaller, since the cohesive force becomes larger. Furthermore, as the powder supply speed decreases, it takes time to increase the discharge pressure of the powder that collects near the supply port, so the pulsation phenomenon of powder supply becomes more pronounced.

Conventionally, there has been no powder supply device capable of quantitatively and continuously supplying fine powder without causing such a pulsation phenomenon.

The purpose of the present invention is to prevent the occurrence of pulsation and enable quantitative continuous supply in an apparatus for supplying fine powder having an average grain size of 30 μm or less.

[Means for Solving the Problems] The present invention provides a powder quantitative supply device that includes a powder fluidizing cylinder to which high-frequency vibration is applied, and a vibrating body having a large number of small holes inside the cylinder. It is characterized by having one or more pieces installed, and essentially consists of the following two elements. The first step is to fluidize the powder by applying high-frequency vibrations to the fine powder, and the second step is to discharge the fluidized powder from the many small holes opened in the diaphragm. .

The former is for reducing the cohesive force between powders, and the latter is for cutting out a constant amount of powder even when the resonance part of the diaphragm moves. This movement of the resonant part is a phenomenon that often occurs in vibrating devices, and in this device, the movement occurs once every few minutes.
Occurs about once. The above matters will be explained in detail below.

[Operation] First, high-frequency vibrations are applied to fine powder to fluidize the powder. Let's do it. High-frequency vibrations can be generated using a conventional oscillator and vibrator. The vibration frequency is
A range of several thousand to several thousand Hz is appropriate, and a range of about 10,000 to 20,000 Hz is particularly preferred.

By applying such high frequency vibration, the average particle size can be reduced to 3.
Even fine powder particles of 0 μm or less can be fluidized, and can be discharged from small holes with a diameter of 0.1 to 3.0 mm.

Next, the powder is discharged by providing small holes in the diaphragm itself to which high-frequency vibrations are applied. This is because by doing so, the powder near the small holes can be completely fluidized. The diameter of this small pore is an average particle size of 30IL.
When discharging several to several tens of grams of fine powder per minute, a suitable range is 0.1 to 3.0 m.

Now, when high-frequency vibration is applied, not only the diaphragm vibrates, but also the parts around it vibrate at the same time. In this case, since the boundary conditions of vibration are not constant, the vibration state is not constant, and therefore the resonance point is not determined. In other words, each part of the diaphragm does not vibrate with the same intensity, but the positions of the parts with strong vibration and parts with weak vibration are not constant, and their positions change over time as they move on the diaphragm. It moves along with. Naturally, the degree of fluidization of the powder on the diaphragm also changes with time. For this reason, if there is only one small hole in the diaphragm, the state of fluidization of the powder at that position will change over time, and therefore,
The amount of powder discharged also changes over time.

In order to solve this problem, in the present invention, first, the size of the diaphragm is made large enough to cover all the parts where the resonance point moves,
A small hole was opened in the entire area.

In this way, it can be used even in locations where vibration is strong due to resonance.
Small holes are also opened in locations where vibration is weak, and even if the resonance point moves, a constant amount of powder will always be discharged considering the small holes as a whole.

Now, regarding the movement range of the resonance point, it depends on the method of fixing the diaphragm, but it depends on the vibration wavelength. /101iS! It is considered to be a degree, and is approximately the number 1. Therefore, if the diaphragm is circular, its diameter may be several cm. Also, regarding small holes,
Although it is preferable to open the holes as densely as possible throughout the JJ plate, there are also processing limitations, so for a diaphragm with a diameter of several 1, it is preferable to drill several hundred to a thousand small holes. Moreover, the diameter of the small hole is 0.1 to 3.0 mm as mentioned above.
is appropriate. This will be explained below using the drawings.

[Example] In FIG. 1, fine powder 3 stored in a hopper 2 is stirred by a stirring blade 4 directly connected to a drive motor 1.
It falls onto the upper diaphragm 5. Now, the high frequency vibrator 9 vibrates due to the high frequency vibration generated by the high frequency generator 10,
This vibration is applied as a high frequency vibration to the fluidizing tube 7 through the vibration transmission horn 8. As a result, the upper diaphragm 5 vibrates, and the fine powder is fluidized and falls onto the lower diaphragm 6.

This is further fluidized by the vibration of the lower vibration plate 6, and a constant amount of fine powder 11 is always discharged. The reason why two diaphragms 5 and 6 are provided in this embodiment is to keep the pressure of the powder applied to the lower diaphragm 6 constant. In this case, it is preferable to adjust the diameter of the small holes and the number of small holes so that the amount of powder discharged from the upper diaphragm 5 is larger than that from the lower diaphragm 6. In this way, the amount of powder present in the fluidizing cylinder 7 is always constant. However, the upper diaphragm 5 is not always necessary, and in particular, when the volume of the hopper 2 is sufficiently large compared to the powder discharge amount and the change in the amount of powder in the hopper 2 is small, the lower diaphragm 5 6
Since the pressure of the powder applied to the lower diaphragm 6 hardly changes, it is sufficient to use only one lower diaphragm 6.Furthermore, the fluidization tube 7 does not necessarily have to be vertical; If you are coming from the area, you can install it in any direction along the route.

Now, in order to control the amount of powder discharged, it is sufficient to change the output of the high frequency vibrator 9. Furthermore, as the diameter and number of small holes in the diaphragm increase, it is natural that the discharge amount increases.

The results of an experimental example in which Si powder having an average particle size of 10 μm was discharged using the apparatus shown in FIG. 1 are shown in Table 1 below.

In this example, the upper and lower diaphragms are circular,
Both diameters are 24 mm. Also, No. 8.9 has only one diaphragm at the bottom. As is clear from the standard deviation of the discharge amount per minute in Table 1, the powder discharge amount is unstable when the diaphragm has one small hole shown in Nos. 091 to 3. It is stable when the number of small holes in the diaphragm 4 to 9 is large. In particular, when the number of small holes in the diaphragm is 853 as shown in Nos. 016 to 9, the amount of powder discharged is extremely constant, especially when two diaphragms are used, an upper and a lower one. Recognize.

[Effects of the Invention] According to the present invention, it has become possible to continuously and quantitatively supply fine powder without pulsation and with high precision.

[Brief explanation of drawings]

FIG. 1 is a front view of a fine powder quantitative supply device according to the present invention. 5: Upper diaphragm 7: Fluidization tube 9: High frequency vibrator 11: Discharged fine powder 6: Lower diaphragm 8: Vibration transmission horn 10: High frequency generator patent applicant Shin Nippon! ! ! 12th Iron Co., Ltd. Agent Patent Attorney Ia Ko Sugi

Claims (1)

[Claims] In a fine powder quantitative supply device using vibration, a powder fluidizing cylinder to which high frequency vibration is applied by a high frequency vibrator has a structure in which one end is connected to a hopper and the other end is open to discharge powder. A fine powder quantitative supply device characterized in that one or more diaphragms having a large number of small holes are installed in the powder fluidizing cylinder.