JPH04365070A - Powder conveyor - Google Patents

Abstract

PURPOSE:To reduce the power consumption, reduce noise, improve the conveyance efficiency, and perform branch conveyance at multiple positions. CONSTITUTION:A hopper 1 feeding powder and an acrylic hollow pipe 2 which is a tubular powder conveying member are provided. The hollow pipe 2 is branched into two in the middle and extended long in the longitudinal direction. Ultrasonic vibration generating piezoelectric elements 3 serving as vibration generating means are arranged at a fixed interval in the longitudinal direction of the hollow pipes 2, and AC voltage is applied by AC power sources 4. The piezoelectric element 3 is the type pinching a ceramic with electrodes from both faces. The hollow pipes 2 between the piezoelectric elements 3 are connected by vibration absorbing members 5. When voltage is applied across the electrodes, the expanding/shrinking vibration is excited in the inner and outer diameter directions by the expanding/shrinking force of the ceramic, the vibration is transmitted as the traveling wave on the hollow pipes 2, and the powder in the hollow pipes 2 is conveyed by the traveling wave in the opposite direction to the traveling wave.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for conveying powder.

0002

BACKGROUND OF THE INVENTION Conventionally, the most common technique for conveying powder is the use of 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.

0003

However, in the conventional example described above, since the screw in the pipe must be rotated by a motor, there are problems in that the power consumption is large and the rotation noise is relatively loud.

[0004] Furthermore, since a comparatively complicated member such as a screw and a motor are required in terms of construction, the device becomes large in size, and furthermore, there are problems in that the cost becomes high.

[0005] Furthermore, if the gap between the screw and the inner wall of the pipe 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, but the rotation of the screw will be reduced due to the friction between the screw and the inner wall of the pipe. Another problem was that the torque increased.

Furthermore, the powder may deteriorate or break due to friction between the inner wall and the screw, or may melt due to frictional heat. In addition, since powder is generally easily charged, the powder often becomes charged during transportation and adheres to the screw, and in severe cases, there is a problem that transportation failure occurs.

In addition, since the screw is passed through the pipe, it is very difficult to carry out branched conveyance to two or more locations, and in order to carry out branched conveyance, a means to temporarily store the powder is required, making the equipment complicated. There was a problem that it became

[0008] The present invention solves the above-mentioned problems, and aims to provide a powder conveying device that has low power consumption, low noise, has good conveyance efficiency, and is capable of branching conveyance to multiple locations. There is.

[0009]

[Means for Solving the Problems] According to the present invention, the above object is to provide a powder conveying member in the form of a tube or gutter which is formed by branching in a plurality of directions and conveys powder in each branching direction; This is achieved by providing at least one vibration generating means disposed before and after the branching of the body conveying member, and a vibration absorbing member connecting the powder conveying member between the vibration generating means.

0010

According to the present invention, vibrations are generated in the radial direction of the powder conveying member by the vibration generating means disposed before and after the branching of the powder conveying member. Then, traveling waves are generated in both longitudinal directions of the powder conveying member before and after the branching, centering on each vibration generating means. However, a vibration absorbing member is attached near one side of each vibration generating means, and the generation of a backward traveling wave traveling in the direction in which the vibration absorbing member is attached is suppressed to prevent interference between the traveling waves. Therefore, the traveling waves generated from each vibration generating means are only those traveling in the direction opposite to the direction in which the vibration absorbing member is attached, and the traveling waves are combined. Thus, the powder in the branched powder conveying member is conveyed in the direction opposite to the direction of the combined traveling wave, and in each branching direction of the powder conveying member.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First to fourth embodiments of the present invention will be described with reference to the accompanying drawings.

First Embodiment First, a first embodiment of the present invention will be described with reference to FIGS. 1 to 10.

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

In FIG. 1, 1 is a hopper for supplying powder, and 2 is an acrylic hollow pipe that is a tubular powder conveying member. The hollow pipe 2 has an outer diameter of 15 mm and an inner diameter of 1
At 0 mm, it branches into two parts in the middle and each part extends long in the longitudinal direction.

Ultrasonic vibration generating piezoelectric elements 3 serving as vibration generating means are arranged at regular intervals in the longitudinal direction of the hollow pipe 2, and an AC voltage is applied to them by an AC power source 4.

The piezoelectric element 3 has an outer diameter 3 as shown in FIG.
0mm, inner diameter 15mm, thickness 2mm ceramic PZT
It is a type that is sandwiched between electrodes from both sides.

By applying a voltage between the electrodes, as shown in FIG. 3, the expansion and contraction force of the ceramic excites expansion and contraction vibrations in the inner and outer diameter directions, that is, in the r direction, and the vibrations are transmitted to the hollow pipe 2 as traveling waves. be done. The powder in the hollow pipe is transported by the traveling wave generated by the piezoelectric element 3 in a direction opposite to the direction of the traveling wave (direction of arrow A in FIG. 1). In addition, in the above embodiment, the peak-to-peak voltage 1
An alternating current voltage of 00 V and a frequency of 50 KHz is applied. This is a value calculated from the resonance mode 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 example, the piezoelectric element is only one layer, but if a multiple sandwich type (multilayer type) is used as shown in Fig. 4, the amount of excited vibration can be further increased, and the traveling wave transmitted to the hollow pipe will also be larger. The powder conveying force also increases. Further, as shown in FIG. 5, 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, it is possible to obtain various vibration modes. Specifically, the electrode arrangement shown in FIG. 6 can excite a uniaxially symmetrical vibration called the ((1,1)) mode shown in FIG.

Furthermore, if the electrode division is subdivided as shown in FIG. 8, parallel vibration of the central axis called the ((2,1)) mode can be excited as shown in FIG. Furthermore, by shifting the phase of the AC voltage applied to these electrodes by 90 degrees, a rotational mode of vibration is also possible.

[0019] In this way, many vibration modes can be excited by subdividing the electrodes and shifting the phase of the voltage applied to each electrode, and by utilizing these various modes, it is possible to control the characteristics of various powders. By selecting the most suitable excitation mode for each powder, you can obtain sufficient transport force for each powder.

[0020] The mass, specific gravity, slipperiness, adhesion, and chargeability of the powder vary to suit each powder, and even if the hollow pipe is the same, the transportability of the powder will depend on the characteristics of the powder itself. This is because it strongly depends on The same thing can be said even if the material, surface properties, and chargeability of the hollow pipe are changed.

However, when a plurality of piezoelectric elements are connected to a long hollow pipe to transport powder over a long distance, the vibrations generated by the piezoelectric elements always generate symmetrical traveling waves around the piezoelectric element. , it becomes impossible to transport powder in one direction. This phenomenon will be explained using FIG. 15.

FIG. 15(B) shows a schematic diagram of traveling waves generated by a plurality of piezoelectric elements in the same long hollow pipe. Moreover, FIG. 15(C) shows a schematic diagram of the vibration of the traveling wave excited in the hollow pipe after combining the respective traveling waves, and the magnitude and directionality of the powder conveying force due to the traveling wave. As is clear from these, the powder conveying force acts in the direction of each piezoelectric element, making it impossible to convey the powder in one direction. As a result, the

Therefore, in the present invention, the hollow pipe between the piezoelectric elements is divided as shown in FIG. 1, so that the traveling waves generated by the piezoelectric elements do not interfere with the traveling waves generated by other piezoelectric elements.

Furthermore, in order to minimize the influence of the self-generated reverse traveling waves, the hollow pipe near the piezoelectric element where the backward traveling waves are generated is cut, and a member that absorbs vibrations but does not transmit them, a so-called vibration absorbing member, is installed. I am intervening.

In order to explain the action of this vibration absorbing member, FIG. 10(B) shows a schematic diagram of each traveling wave generated by the piezoelectric element.

As shown in FIG. 10, the traveling wave transmitted through the hollow pipe 2 is attenuated by the vibration absorbing member 5, and the traveling wave is not transmitted to the adjacent hollow pipe 2.

FIG. 10C shows the vibration of the traveling wave excited in the hollow pipe 2 after combining the respective traveling waves.

[0028] By cutting the hollow pipe 2 where the backward traveling waves occur and interposing a vibration absorbing member between them, the influence of the backward traveling waves can be suppressed to a small level, and powder conveyance as shown in FIG. 10(C) can be achieved. It becomes possible to have the magnitude and direction of force.

As is clear from this, the effective powder conveying force acts in a fixed direction, and as shown in FIG.
Powder is strongly conveyed in this direction. That is, by shifting the position of the vibration absorbing member from the midpoint between adjacent piezoelectric elements, powder can be transported in the opposite direction to the shifting direction, and the closer it is to the piezoelectric elements, the more the transport force increases.

Furthermore, the vibration width at the end of the hollow pipe 2 in contact with the vibration absorbing member 5 is 1/1 of the vibration width at the piezoelectric element portion.
If it is not attenuated to 2 or less, the influence of the reflected wave at the end becomes large, and the attenuation of the carrier force of the traveling wave becomes large, which is not preferable.

In this embodiment, vibration-proofing rubber (NBR) was used as the vibration-absorbing member 5, and a hollow acrylic pipe was connected to the vibration-proofing rubber using a silicone adhesive.

Further, in this embodiment, as shown in FIG. 1, a bifurcated conveyance path is used, and the hollow acrylic pipes 2-1, 2-2 are connected to the hollow acrylic pipe 2 from two directions by the vibration absorbing members 5-1, 5. -2. One piezoelectric element 3-1, 3-2 is arranged in each of the hollow acrylic pipes 2-1, 2-2, and a traveling wave is generated by each piezoelectric element and propagates to the joint of the hollow acrylic pipe. The vibration absorbing members 5-1 and 5-2 do not interfere with each other. Therefore, the powder conveyed by the piezoelectric element 3 of the hollow acrylic pipe 2 is divided into two parts and conveyed to the hollow acrylic pipes 2-1 and 2-2 by the respective traveling waves, and is finally transported along the longitudinal direction in the A1 and A2 directions. The powder will be transported in the direction.

As described above, according to this embodiment, the length 2
It was possible to transport a long distance of m in two directions. As mentioned above, as an acrylic pipe, the outer diameter is 15 mm,
When a one-component magnetic toner with an inner diameter of 10 mm and a powder with an average particle size of 12 μm was used, A1,
The powder conveying force in the A2 direction was 250 g/min.

Furthermore, the powder may be used as glass beads with an average particle size of 60 μm, ferrite carrier with an average particle size of 60 μm, or non-magnetic toner with an average particle size of 8 μm, or a mixture thereof may be used to transport the powder in the same way as the magnetic toner. It turned out to be powerful.

Furthermore, the amount of powder conveyed in the A1 and A2 directions can be controlled by the voltage applied to the piezoelectric element, making it possible to control the distribution and conveyance of the powder.

In other words, in this example, an AC voltage (voltage 100 V, frequency 50 KHz) of the same phase and voltage was continuously applied, but the vibration absorbing member causes each piezoelectric element to act as an independent event, and each voltage element Even if the phase, application time, and applied voltage are changed, the powder conveying force of that voltage element can be controlled without affecting other voltage elements.

[0037] The above results also show that the size of the conveying member,
This means that there is no problem even if the shape is changed. Therefore, even when a large number of conveying members are joined together in a narrow area, ON/OFF control of each powder conveyance and control of the amount of powder conveyed are possible.

In addition, the material used for the powder conveying member should preferably have a relatively large attenuation rate, and if the amplitude of the generated excitation is less than 1/2 at the end, the influence of reflected waves will be reduced. It was found that the conveyance capacity was excellent. According to experiments, acrylic, nylon, POM (polyacetal)
, ABS, polypropylene, polystyrene, etc. are suitable.

[0039] Also, NBR, urethane rubber, Si rubber, EKDM, gel resin, Si rubber adhesive, etc. are most suitable as vibration absorbing members, and by reducing the hardness of the rubber, almost 100% of traveling wave vibrations can be absorbed. It is possible. Furthermore, experiments have shown that when the vibration absorption rate is 50%, if the amplitude of the traveling wave propagating through the vibration absorbing member is attenuated to 1/2 or less, the traveling wave generated from the adjacent hollow pipe and piezoelectric element is hardly affected and the It was also found that body transport was carried out smoothly.

[0040] As described above, since there is no conveying member such as a screw inside the hollow pipe, it is possible to carry out branch conveyance in a small size, low noise, efficiently, and without deteriorating, destroying, or melting the powder.

<Second Embodiment> Next, a second embodiment of the present invention will be explained based on FIGS. 11 and 12. Note that the same reference numerals are given to the same parts as in the first embodiment, and the explanation thereof will be omitted.

In the first embodiment, vibration absorbing members 5-1 and 5-2 were provided at the joints of each powder conveying member to connect them, but when the joints are complicated, it may be necessary to connect them as shown in FIG. Alternatively, a joining method may be used in which the branch portion is formed by integral molding and the vibration absorbing member 5 is brought close to the piezoelectric element 3.

However, hollow acrylic pipes 2-1, 2-
Even if the influence of each reflected wave is minimized by the cross-sectional shape of the joint portion of 2, standing waves are generated due to interference of mutual traveling waves, making branching and conveyance difficult. Therefore, in this example,
Piezoelectric elements 3-1, 3- are used as a means to improve conveyance efficiency.
We adopted a method to make each traveling wave an independent event by shifting the application timing of 2. As a result, each piezoelectric element 3-1, 3
It has become possible to eliminate the influence of -2 and suppress the decline in powder branching and conveying ability as much as possible. Incidentally, in this embodiment, the piezoelectric element power supplies 4-1 and 4-2 were repeatedly turned on and off at 1 sec intervals at a VPP of 100 V and a frequency of 50 KHz. The power source 4 for the piezoelectric element has a VPP of 100 V, a frequency of 50 KHz, and repetition at 0.5 sec intervals. This is from the conveyance path 2 to the hollow acrylic pipes 2-1 and 2.
This is to ensure smooth transfer of powder to -2.
In order to avoid clogging the powder at the bifurcated joint and to evenly branch and convey the powder, it is preferable that the repetition frequency be an integral multiple of the repetition frequency of the piezoelectric element power supplies 4-1 and 4-2 (see FIG. 12).

As a result of an experiment conducted under the above conditions, when a one-component magnetic toner was used as the powder, the powder conveyance force was the same for both A1 and A2, 200 g/min.

[0045] Also in this embodiment, the power supplies 4, 4-1
, 4-2, the amount of branched conveyance can be controlled by changing the VPP, application time, and period.

In this embodiment, the timings 4-1 and 4-2 are set so as not to interfere with each other, but even if they overlap to some extent, a sufficient conveying force can be ensured.

<Third Embodiment> Next, a third embodiment of the present invention will be described based on FIG. 13. Note that the same reference numerals are given to the same parts as in the first embodiment, and the explanation thereof will be omitted.

FIG. 13 shows a third embodiment. In this example,
A groove-shaped conveying member 6 is used instead of the hollow pipe 2, and since the traveling wave of the piezoelectric element is transmitted regardless of the shape of the conveying member 6, the powder can be conveyed in branches using the same conveying principle as in the first embodiment. is possible.

According to this embodiment, since the pipe is not a hollow pipe but has an open top, it is easy to supply another powder through this opening.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described based on FIG. 14. Note that the same reference numerals are given to the same parts as in the first embodiment, and the explanation thereof will be omitted.

FIG. 14 shows a fourth embodiment. In this example,
A piezoelectric element 3 is fixed to the lower part of a hollow pipe 2.

According to this embodiment, a plate-shaped piezoelectric element such as a laminated piezoelectric element is vibrated, and a part of the hollow pipe is vibrated to generate a traveling wave to transport the powder. As in the third embodiment, sufficient branching conveying force can be obtained. With such a configuration, branched powder conveyance can be realized in a simple and compact manner, and it is also advantageous in terms of pipe replacement, cost, etc.

[0053]

[Effects of the Invention] As explained above, according to the present invention,
Since a traveling wave is generated by applying vibration in the radial direction by the vibration generating means to the powder conveying member connected by the vibration absorbing member, the powder can be efficiently conveyed over a long distance with less energy. Further, the powder can be quietly and smoothly transported in multiple branches without deterioration, damage, or melting.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a schematic configuration of a device according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a schematic configuration of vibration generating means of the device shown in FIG. 1;

FIG. 3 is a diagram showing changes in the outer wall of the powder conveying member of the apparatus in FIG. 1;

FIG. 4 is a perspective view showing a schematic configuration when the means of FIG. 2 are stacked.

5 is a perspective view showing a schematic configuration of the means shown in FIG. 2 in which electrodes are provided around the circumference; FIG.

FIG. 6 is a diagram showing a ((1,1)) mode electrode arrangement of the means of FIG. 2;

7 is a diagram showing changes in the outer wall of the powder conveying member in the case of the arrangement shown in FIG. 6. FIG.

8 is a diagram showing a ((2,1)) mode electrode arrangement of the means of FIG. 2; FIG.

9 is a diagram showing changes in the outer wall of the powder conveying member in the case of the arrangement shown in FIG. 8. FIG.

10: (A) is a diagram showing the state of powder inside the powder conveying member of the apparatus shown in FIG. 1; (B) is a diagram illustrating traveling waves generated within the powder conveying member of the apparatus shown in FIG. 1; C) is (
It is a figure explaining the traveling wave after combining each traveling wave of B).

FIG. 11 is a diagram showing a schematic configuration of a device according to a second embodiment of the present invention.

FIG. 12 is a diagram showing the application timing and powder conveyance amount of each piezoelectric element in the device shown in FIG. 11;

FIG. 13 is a diagram showing a schematic configuration of a device according to a third embodiment of the present invention.

FIG. 14 is a diagram showing a schematic configuration of a device according to a fourth embodiment of the present invention.

FIG. 15(A) is a diagram showing the state of powder inside the powder conveying member when a plurality of piezoelectric elements are connected to the powder conveying member without using a vibration absorbing member, and (B) is a diagram showing the state of powder inside the powder conveying member. A) is a diagram illustrating each traveling wave generated in the powder conveying member, and (C) is a diagram illustrating the vibration of the traveling wave excited in the powder conveying member after combining the respective traveling waves in (B), and It is a figure explaining the magnitude|size and directionality of the powder conveyance force by the traveling wave.

[Explanation of symbols]

2 Powder conveyance member (hollow pipe) 3 Vibration generating means (piezoelectric element) 5 Vibration absorbing member

Claims (3)

[Claims] 1. A powder conveying member in the form of a tube or gutter which is formed by branching in a plurality of directions and conveys powder in each branching direction, and at least one or more disposed before and after the branching of the powder conveying member. What is claimed is: 1. A powder conveying device comprising: vibration generating means; and a vibration absorbing member connecting powder conveying members between the vibration generating means. 2. The powder conveying device according to claim 1, wherein the vibration generating means uses a piezoelectric element. 3. The powder conveying apparatus according to claim 2, further comprising a control means for suppressing interference of traveling waves by controlling the magnitude, time, and timing of the voltage applied to each vibration generating means to be different. .