JPH04125214A - Powder transport method - Google Patents

Abstract

PURPOSE:To transport powder in a long distance with a small energy by generating a progressive wave by way of giving oscillation to a powder transport member in the radial direction and damping the progressive wave toward the end part. CONSTITUTION:A piezoelectric element 2 for generation of supersonic oscillation is provided on the end part of a hollow pipe 1 in the longitudinal direction, and an alternating voltage is applied from a power source 3 and oscillation is generated on an outer wall in the radial direction. Thereafter, a progressive wave is generated in the hollow pipe 1 in the longitudinal direction. The hollow pipe 1 is made of acrylic and has a comparatively large damping force, and therefore, the progressive wave is to be damped toward the other end part. Accordingly, a reflective wave is to be little on the end part and the progressive wave is not disturbed. Then, powder in the hollow pipe 1 is transported in the A direction which is the reversal direction of the direction of the progressive wave. Consequently, it is possible to transport powder with a small energy in a long distance, control the transport amount by way of changing an applied voltage and improve transport efficiency.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for conveying powder.

[Prior Art] Conventionally, the most common technique for conveying powder is one using a screw, which is used in all types of powder conveying means. In this method, for example, powder inside a pipe is transported by rotating a screw provided inside the pipe.

[Case II to be solved by the invention] However, in the conventional example described above, the screw in the pipe had to be rotated by a motor, which resulted in problems such as high power consumption and relatively loud rotation noise. .

The configuration also requires a relatively complicated member called a screw and a motor, which takes up space and increases costs.

Also, if the gap between the inner wall of the pipe and the screw is large, the conveyance efficiency will decrease, and conversely, if the gap between the screw and the inner wall of the pipe is small, the conveyance efficiency will increase, or the rotational torque of the screw will increase due to the friction between the screw and the inner wall of the pipe. It also had the problem of becoming.

Furthermore, the powder deteriorates due to friction between the inner wall and the screw, etc.
It may break or melt due to frictional heat.Also, since powders are generally not electrically charged, they often become electrically charged during transport and adhere to the screws, and in severe cases, a transport failure may occur. There was also the problem of doing so.

It is an object of the present invention to solve the above-mentioned problems and provide a powder conveying device with low power consumption, low noise, and high conveying efficiency.

[Means for Solving the Problems] According to the present invention, the above object is to apply vibration in the radial direction by a vibration generating means to one end of a powder conveying member that conveys powder in the longitudinal direction, and to This is achieved by conveying the powder in a predetermined direction within the powder conveying member by generating a traveling wave in one direction and attenuating the traveling wave toward the other end.

[Operation] According to the present invention, the vibration generating means generates vibration in the radial direction of the powder conveying member to generate a traveling wave. The traveling wave advances to the end of the powder conveying member, or in this case,
Since the traveling wave is gradually attenuated, no reflected wave is generated at the end.

In this way, the traveling wave becomes stable, and the powder is transported in a direction opposite to the traveling direction of the traveling wave.

[Embodiments] First to third embodiments of the present invention will be described based on the accompanying drawings.

<First Embodiment> First, FIGS. 1 to 9 regarding the first embodiment 2 of the present invention.
This will be explained using figures.

FIG. 1 shows a first embodiment of the present invention. This device is a powder conveying device that utilizes the present invention.

Reference numeral 1 in FIG. 1 is an acrylic hollow pipe serving as a powder conveying member. The inside is filled with powder (not shown). An ultrasonic vibration generating piezoelectric element 2 serving as vibration generating means is provided at the front end of the hollow pipe 1 in the longitudinal direction, and an alternating current voltage is applied by an alternating current power source 3. As shown in FIG. 2, the piezoelectric element 2 generates ultrasonic vibrations that cause the cross-sectional outer wall of the hollow pipe 1 to vibrate as indicated by the two-dot chain line (in the r direction).

Excited by the piezoelectric element 2, the hollow vibe 1 generates a traveling wave as shown in FIG. Since the hollow vibrator l is made of acrylic, it exhibits a relatively large attenuation characteristic, and the traveling wave is attenuated as shown in FIG. Therefore, there is almost no reflected wave at the end, and it is not disturbed by traveling waves or reflected waves.

With this configuration, the powder inside the hollow pipe is transported in the direction opposite to the direction of the traveling wave (A in FIG. 1).

Further, the vibration mode is not limited to the moat shown in FIG. 2, and may be excited as shown by the chain double-dashed line in the cross-sectional view of the hollow pipe (only the outer wall is shown) in FIG. 4 (A) or (B), for example.

The following experiments were conducted based on the apparatus of this embodiment as described above. A hollow acrylic pipe with an outer diameter of 15 mm and an inner diameter of 10 mm was used, and a powder supply hopper was connected to the opposite end of the pipe to which the piezoelectric element was attached. Further, a single-component magnetic toner having an average particle size of 12 layers was used as the powder. As a result of the experiment, the conveying force of this powder was 5011 g/sin.

Furthermore, the same conveying force as that of magnetic toner can be obtained by using powders of glass beads with an average particle size of 601 L, ferrite carrier with an average particle size of 60 L, non-magnetic toner with an average particle size of 81 L, and a mixture thereof. I realized that.

At this time, the amount of powder conveyed changes in proportion to the voltage applied to the piezoelectric element, making it possible to control the amount of powder conveyed.

Further, the voltage application time may be changed in a pulse manner.

The piezoelectric element 2 is of a type in which ceramic PZT having a thickness of 211 mm is sandwiched between electrodes from both sides, as shown in FIG.

By applying a voltage between the electrodes, expansion and contraction vibrations are excited in the inner and outer diameter directions, that is, in the r direction, due to the expansion and contraction force of the ceramic, and the vibrations are transmitted to the hollow pipe 1 as traveling waves. Also, peak-to-peak voltage 100V, frequency 50K
When an AC voltage of Hz is applied, this value is calculated from the resonance moat depending on the shape of the piezoelectric element, and the resonance frequency can be changed by changing the thickness and shape of the piezoelectric element. In addition, in this embodiment, the piezoelectric element is only in one layer or in the sixth layer.
Multiple sandwich type (multi-layered type) as shown in the figure
As the amount of excitation vibration becomes larger, the traveling wave transmitted to the hollow vibrator also becomes larger, and the powder conveying force also increases.

Further, as shown in FIG. 7, electrodes may be provided around the circumference of the piezoelectric element. Furthermore, by subdividing the electrodes of the piezoelectric element and changing the polarity of the applied voltage, various modes of vibration can be obtained.
T'f? bawl.

Specifically, by using the electrode arrangement shown in FIG. 8, it is possible to excite l-axis symmetrical vibration called ((1,1)) soto shown in FIG. 4(A).

Furthermore, if the electrode division is further subdivided as shown in FIG. 9, parallel vibrations of the central axis called ((2,1)) vibrations, as shown in No. 41A ([3)], are excited. Furthermore, by shifting the phase of the alternating current voltage applied to these electrodes by 90 degrees, a rotating mode of vibration is also possible.

In this way, by subdividing the electrodes and shifting the phase of the voltage applied to each electrode, many vibration motes can be excited. By utilizing these various motes, it is possible to select the optimal excitation mode that matches the characteristics of various powders and obtain sufficient conveying force for each powder.

This is because the mass, specific gravity, slipperiness, adhesion, and chargeability of powder vary, and even if the hollow vibrator is the same, the transportability of powder strongly depends on the characteristics of the powder itself.

This example uses an acrylic hollow pipe, and in this configuration, the amplitude of vibrations applied to a part of the acrylic hollow pipe, which is a powder conveying member, is attenuated by absorption of the vibration of that member, that is, the acrylic hollow pipe itself. has been done. The present invention is configured such that the amplitude of the excited powder conveying member is attenuated at the end in the direction of the traveling wave, and a traveling wave is generated to convey the powder. It is effective and can be realized easily and inexpensively.

In addition to using materials with high attenuation, the structure can also be made using materials with low attenuation, such as attaching a material with high attenuation to a part of the metal pipe, or adding grooves to the shape of the metal pipe itself to increase the attenuation. There are several examples.

As mentioned above, the feature of the present invention is that it suppresses the reflected wave at the end of the incident wave or the overlapping of the traveling wave and hinders the conveyance of the powder. Conveyance member, ■ is acrylic hollow pipe diameter 20++n
, ■ is the diameter of the hollow acrylic pipe ioam, (φ is the hollow aluminum pipe with a diameter of 18 mm and covered with acrylic from [1) to make the diameter 20 mm.The length of the pipe used was changed from 10 cm to 1 m in the experiment. I did it.

As a result of the experiment, if the ratio of the end amplitude to the incident radiation is used as a parameter, the results will be the same regardless of the length.)
is.

Furthermore, from these results, it can be seen whether it is desirable for the amplitude of the powder conveying member excited by the vibration generating means to be less than the amplitude at the end thereof.

Materials include acrylic, nylon, POM, ABS,
Polypropylene, polystyrene, etc. are suitable.

(The following is a blank space) Second Embodiment> Next, a second embodiment of the present invention will be described based on FIGS. 10 and 11. Note that the same reference numerals are given to the same parts as in the first embodiment, and the explanation thereof will be omitted.

This embodiment differs from the first embodiment in that a groove-shaped conveying member 1 is used instead of the hollow barb 2, as shown in FIG. 111. In this embodiment as well, acrylic is used for the conveying member.

The principle of conveyance is the same as in the first embodiment, in which a voltage is applied from the AC power source 3 to the piezoelectric elements 2 to attenuate the traveling waves of each piezoelectric element to convey the powder in the long groove.

This has the advantage that powder can be easily replenished through the groove opening because the upper part is open instead of a hollow pipe.

Furthermore, as shown in FIG. 11, the same effect can be obtained even if the powder conveying member l is shaped like a gutter.

<Third Embodiment> Next, a third embodiment of the present invention is shown in FIGS. 12 and 13 (A
) and (B). Note that the same reference numerals are given to the same parts as in the first embodiment, and the explanation thereof will be omitted.

This embodiment differs from the first embodiment in that the piezoelectric element 2 is fixed to the lower part of the hollow pipe 1, as shown in FIG. This is a plate-shaped piezoelectric element such as a laminated piezoelectric element as shown in Figure 13 (A).
, as shown in (B), a part of the hollow pipe is vibrated and struck by a piezoelectric element to generate a traveling wave from a part to transport the powder. As in the other embodiments, there is a sufficient transport part. occurs.

With such a configuration, powder transportation can be realized in a simple and compact manner, which is advantageous in terms of pipe replacement, cost, etc.

[Effects of the Invention] As explained above, according to the present invention, the vibration generating means applies vibration to the powder conveying member in the radial direction to generate a traveling wave, and directs the traveling wave toward the end. By attenuating it, powder can be efficiently transported over long distances with less energy.

In addition, the powder does not deteriorate, break, or melt, and
It can be transported smoothly.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a device according to a first embodiment of the present invention, and FIG. 211! ! J is a diagram illustrating the vibration of the outer wall of the powder conveying member in the first device, FIG. 3 is a diagram showing traveling waves generated in the device shown in FIG. 1, and FIG. Figure 4 shows the l-axis symmetrical vibration of the body conveying member (
6) is a diagram showing the non-axisymmetric vibration of the powder conveying member in the device shown in FIG. 1, FIG. 5 is a diagram showing a schematic configuration of the vibration generating means of the device shown in FIG. 1, and FIG. 7 is a diagram showing a schematic configuration when electrodes are provided on the circumferential part of the means shown in FIG. 5, and FIG. )) mode, FIG. 9 is a diagram showing the electrode arrangement in the ((2,1)) mode of the means shown in FIG. FIG. 11 is a perspective view showing a schematic configuration when the powder conveying member of the device shown in FIG. , Figure 13 (
A) is a diagram showing a vibration form of the vibration generating means of the apparatus shown in FIG. 12, and FIG. 13(B) is a diagram showing another vibration form of the vibration generating means of the apparatus shown in FIG.

Claims (6)

[Claims] (1) Vibration is applied in the radial direction by a vibration generating means to one end of the powder conveying member that conveys the powder in the longitudinal direction, and the vibration generates a traveling wave in the longitudinal direction. A powder conveying method that conveys powder in a predetermined direction within the powder conveying member by attenuating a traveling wave. (2) The powder conveying method according to claim 1, wherein the traveling wave is attenuated by absorbing vibrations of the powder conveying member itself. (3) The powder conveying method according to claim (1), wherein the amplitude of the traveling wave at the end of the powder conveying member in the traveling wave direction is set to be half of the vibration generating means attachment position. (4) The powder conveying method according to any one of claims (1) to (3), wherein a piezoelectric element is used as the vibration generating means. (5) The powder conveying method according to any one of claims (1) to (4), wherein the powder conveying member is a hollow pipe. (6) The powder conveying method according to any one of claims (1) to (5), wherein the vibration generating means generates ultrasonic vibration.