JP2000055711A - Powder supply equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly spread powder in a stable state that quantity variation with time is little, and enable reducing aggregation of powder and clogging of the piping. SOLUTION: The entirety of a main vessel 1 of powder supply equipment constitutes an airtight structure sealed from the outside. A diaphragm 2 is installed in the vessel 1, which is divided into a first chamber for spouting the powder and a second chamber for supplying the powder. Consequently, scattering of the powder which is to be caused by an air flow is avoided. In the first chamber for spouting the powder above the diaphragm 2, a hollow pipe 3 for gas flowing and a gas flowing inlet are installed. Only the upper tooth trenches of a gear feeder 5 are made to exist, and the spouting of superfluous powder is prevented. In the second chamber for supplying the powder below the diaphragm 2, the gear feeder 5 having the tooth trenches for packing the powder is accommodated and arranged. By the rotation of the gear, the tooth trenches are filled with the powder. On a wall surface, a powder introducing port 7 for supplying the powder is installed, and a stirring vane 6 of a spiral type for stirring the powder in the second chamber is arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder supply apparatus for supplying a fine powder together with a gas while maintaining a constant amount over time, and more particularly to a device for supplying a powder between a pair of electrode substrates constituting a liquid crystal display panel. The present invention relates to a powder supply device for supplying a powder to be interposed as a spacer to a powder supply device.

[0002]

2. Description of the Related Art In recent years, in various fields, a device for quantitatively and continuously supplying a powder having a fine particle diameter has been required widely.

A description will be given taking a liquid crystal display panel as an example.
The liquid crystal display panel encloses liquid crystal between a pair of electrode substrates,
In this method, information is displayed by switching by utilizing the characteristics of liquid crystal by applying an electric field between the electrodes, and the distance between the pair of electrode substrates needs to be a small and uniform gap of about several μm. In order to form this uniform gap, fine powder is interposed between the pair of electrode substrates as a spacer.

As a method of interposing the powder, a method of spraying the powder by a wet method or a dry method is known. In the dry method, a method of spraying fine powder in a dispersed state on an electrode substrate from a nozzle is known. For example, Japanese Patent Application Laid-Open No. 5-238544
No. 6,086,098 is known.

The powder used for maintaining the gap between the electrode substrates constituting the liquid crystal display panel has a very small particle size of about several μm. However, the powder directly affects the performance of the liquid crystal display panel. The requirements are to satisfy various requirements for the material of the powder to be produced, the uniformity of the particle size, etc., and to ensure that the powder to be sprayed is sufficiently dispersed without agglomeration in order to keep the electrode substrate spacing uniform. However, in addition, it is desired that the powder is sprayed so as not to be unevenly distributed in the powder spraying region but to be present evenly and partially on average.

[0006] The demand for such average application is, for example, 1
It is a severe condition that a variation of about 20 or less is allowed for a specific number of sprays set within a range of about 150 to 250 per mm ² .

For this reason, as a spraying method, an electrode substrate is arranged at a position distant from a jet port provided on the inner surface of the spraying device,
To prevent the relatively large agglomerated powder from settling and being spread on the electrode substrate, avoid the agglomerated powder from being spread on the electrode substrate, or provide a shutter below the spray nozzle provided above the electrode substrate to spray the agglomerated powder. There have been proposed methods of preventing the agglomerated powder from falling onto the electrode substrate at other times, and expanding the dispersion area by rotating the spray nozzle circularly without fixing the spray nozzle.

However, in order to make the distribution of the dispersed powder non-uniform or free of agglomerated powder, it is necessary to take measures for agglomeration of the powder at the time of being supplied to the spraying apparatus in addition to the method of spraying. is there.

For example, when powder is continuously sprayed, if the supply amount per unit time fluctuates greatly when the continuous feeding step is divided into minute unit times, it is necessary to control the spraying conditions strictly. However, it is not possible to obtain a uniform distribution of the spray powder.

[0010] Regarding the agglomerated powder, charging, sticking,
Although liquid bridges or intermolecular forces are conceivable, they are mainly due to charge aggregation, and this aggregation is dispersed by the collision force in the pipe. Further, coagulated powder that is not dispersed is dealt with by absorbing with a cleaner.

[0011]

In recent years, the distance between the electrode substrates of a liquid crystal display panel has been reduced, and finer powder which is difficult to disperse is used as a spacer. Further, in order to prevent the movement of the powder in the liquid crystal display panel, a powder of a type to be adhered to the electrode substrate is also used as the spacer.
As described above, a powder that is more easily agglomerated is used as a spacer than a powder that can be dispersed until now.

It is also said that the smaller the particle size of the powder, the greater the effect of intermolecular force tends to be. Therefore, the powder is more densely packed by compression filling, and the point of contact between the powders is reduced. As the number increases, the bonding force increases. As described above, the powder is compressed and agglomerated by the powder supply device, and the agglomerated powder causes a cell gap defect of the liquid crystal display panel.

Further, in a powder supply apparatus which handles powder that is easy to combine, there is also a connection between the powder and the supply portion, so that residual powder of aggregated powder or clogging of the pipe occurs, and the dispersibility of the powder deteriorates. And other issues.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and when the powder is uniformly sprayed, the powder is supplied in a stable state with little variation over time with respect to the amount of powder. It is an object of the present invention to provide a powder supply device capable of reducing aggregation of the powder and clogging of a pipe.

[0015]

According to a first aspect of the present invention, there is provided a powder supply apparatus, wherein a gas is introduced from a gas inlet to maintain the inside of the powder supply apparatus at a constant pressure. A main body container in which a certain amount of powder is present inside by pouring the powder through a powder input port, and provided in the main body container, the powder is scooped up by a tooth tip, and the scooped powder is A rotating means for measuring by filling the body into the tooth space, a measuring means provided with serrated irregularities on the outer peripheral part, and a trace of the powder present below the inside of the main body container, which is scooped up by the measuring means, is averaged. And a supply unit that discharges the powder measured by the measuring unit from the main body container and supplies the powder to another device.

According to a second aspect of the present invention, there is provided a powder supply apparatus.
In the powder supply device described above, the powder is discharged from the main body container by a pressure difference between the inside and the outside of the main body container.

According to the third aspect of the present invention, there is provided a powder supply apparatus.
Alternatively, in the powder supply device according to claim 2, a partition plate that separates the main body container into an upper part and a lower part is provided, so that only a part of the measuring means is exposed at the upper part, and the gas inlet is provided with the gas inlet. It is characterized by being provided on the upper part.

According to the powder supply apparatus of the present invention, the powder is scooped up at the tip by the measuring means provided with the saw-toothed unevenness, and the scooped powder is filled in the tooth space to thereby prevent the powder from being compressed. The powder can be filled and measured in the state,
Aggregation of the powder can be reduced. further,
By adjusting the rotation speed of the metering means or the width or depth of the tooth space, it is possible to adjust the powder supply amount even if the amount is extremely small, not more than several g / hour. Furthermore, a uniform amount of powder can be measured each time by equalizing the traces picked up by the powder measuring means by the stirring means.

Further, by discharging the powder from the main container by the pressure difference between the inside and the outside of the main container, the supply concentration of the powder to another apparatus can be kept constant, and the conventional powder supply can be maintained. It is possible to quantitatively supply an extremely small amount of powder of several g / hour or less, which has been difficult with an apparatus.

A partition plate for separating the main body container into an upper part and a lower part is provided, only a part of the measuring means is exposed at the upper part, and a gas inlet is provided at the upper part, so that the main body container is pressurized. It is possible to fill and measure the powder in an uncompressed state without agglomerating the powder present below the inside, and it is possible to reduce the agglomeration of the powder.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view showing a schematic configuration of a powder supply device according to the embodiment.

As shown in FIG. 1, the main body container 1 of the powder supply device has an airtight structure as a whole and is sealed from the outside. This main body container 1 is provided with a partition plate 2 so as to divide the inside thereof into two parts. The partition plate 2 is divided into a first chamber related to powder discharge and a second chamber related to powder supply, It is configured to avoid scattering of the body.

In a first chamber above the partition plate 2 relating to powder discharge, a hollow tube 3 and a gas inlet 4 relating to gas inflow and outflow are provided, and a gear feeder 5 relating to powder discharge is provided.
The configuration is such that only the upper tooth space is present and no extra powder is discharged.

In a second chamber below the partition plate 2 related to powder supply, a gear feeder 5 having tooth grooves for powder filling is provided.
Are stored and the powder is filled in the tooth space by the rotation of the gear. A powder inlet 7 for supplying the powder to the wall is provided, and a spiral stirring blade 6 for stirring the powder in the second chamber is disposed.

The rotation direction of the gear feeder 5 is such that the powder is picked up from below toward the stirring blade 6. The stirring blade 6 is arranged so that its axis is perpendicular to the gear feeder 5, is connected by a gear train from a motor that drives the gear feeder 5, and rotates so as to push the powder upward by this power.

Here, the first chamber will be described in more detail with reference to FIG. FIG. 2 is a perspective view showing the first chamber.

As shown in FIG. 2, since the lower end of the hollow tube 3 is opened at a predetermined interval from the tooth groove 8 of the gear feeder 5, the powder is introduced into the hollow tube 3 from the tooth groove 8. And constitutes a powder discharge section for feeding in. The hollow tube 3 is configured such that the distance between the opening at the lower end and the tooth groove 8 can be adjusted by a screw groove.

The pressure of the gas for pressurizing the inside of the main body container is adjusted by the adjusting valve, and the gas is introduced from the gas inlet 4 to pressurize the inside of the main body container. The pressurized gas is discharged from the inside of the hollow tube 3 while being scooped up at the tip of the gear feeder 5 and accompanied by the powder filled in the tooth space 8.

Next, the powder supply operation of the powder supply device will be described.

First, for example, powder used as a spacer for a liquid crystal display panel is charged from a powder input port 7 into a second chamber, which is a powder supply unit, and is picked up by the tip of a rotating gear feeder 5 to form a tooth space. 8 is filled. At this time, the stirring blades 6 stir the powder in the second chamber, and level the traces of the gear feeder 5 scooped up.

The gear feeder 5 is provided with triangular irregularities having a sawtooth shape on the outer periphery of a roll-shaped rotating body. The tooth groove 8, which is a serrated concave portion, had an outer diameter of 70 mm, a tooth pitch of 2 mm, a width of 1 mm, and a tooth tip length of 1 mm. And the supply concentration. When a powder used as a spacer is supplied to the liquid crystal display panel, a material which is unlikely to generate static electricity close to the powder and in a charging line is desirable, and a material made of stainless steel is used.

Next, the powder filled in the tooth space 8 moves to the first chamber, which is a powder discharge part, and the tooth space 8 filled with the powder is rotated by the rotation of the gear feeder 5 to lower the lower end of the hollow tube 3. When the first chamber is located at a position facing the opening, the first chamber is in a pressurized state as described above, so that the first chamber is caught in the flow of the gas flowing out of the hollow tube 3 and the powder filled in the tooth space 8. The body is discharged from the hollow tube 3 and supplied to a powder spraying device or the like.

The hollow tube 3 provided for discharging the powder from the powder supply device has, for example, an inner diameter of 3 mm and is kept at a constant distance from the tooth tip of the outer peripheral portion of the gear feeder 5. The opening at the lower end and the tooth groove 8 are arranged so as to face each other. Since this interval is related to the amount of dispersion or dispersibility in the powder dispersing device that supplies the powder, it differs depending on conditions such as the discharge pressure.
It is preferable to set it to about 0.1 to 3 mm.

With the above-described structure, the powder supplied from the main body container 1 through the hollow tube 3 to the spraying tube of the powder spraying device is in a certain coagulated state when flowing into the hollow tube 3. Even if the hollow tube 3 and the scatter tube move, they are dispersed by colliding with the inner wall of the tube. Although it depends on the type or particle size of the powder, in order to make the effect of powder dispersion during movement of the hollow tube 3 and the dispersion tube more effective, the length of these tubes should be 5 m or more, and the flow rate of gas in the tubes To 40
It is preferably set to 80 m / sec.

When the powder supply device according to the present invention is combined with the powder spraying device, the spraying pressure is 2.0 to 4.5.
It is preferably set to kgf / cm ² . In addition, since the on and off of the dispersion can be controlled by the rotation of the gear feeder 5, stable powder supply and powder dispersion which are not affected by pulsation of the pump and the like can be achieved.

[0036]

As described above, according to the powder supply apparatus of the present invention, the powder is scooped up at the tip by the measuring means provided with the saw-toothed irregularities, and the scooped powder is By filling the body into the tooth space, the powder can be charged and measured in a non-compressed state, and it is possible to reduce the aggregation of the powder. Further, even if the amount is extremely small amount of several g / hour or less, the powder supply amount can be adjusted. further,
Every time a certain amount of powder can be weighed.

Further, by discharging the powder from the main body container by the pressure difference between the inside and the outside of the main body container, the supply concentration of the powder to another apparatus can be kept constant, and at the same time, several g or less per hour. A very small amount of powder can be supplied quantitatively.

Further, a partition plate for separating the main body container into an upper part and a lower part is provided, only a part of the measuring means is exposed at the upper part, and a gas inlet is provided at the upper part, so that the powder can be compressed in an uncompressed state. Can be filled and measured, and the aggregation of powder can be reduced.

When the powder supply device according to the present invention and the powder spraying device are combined, the on and off of the spraying can be controlled by the rotation of the measuring means, so that a stable powder which is not affected by the pulsation of the pump or the like can be obtained. Body supply and powder spraying become possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a powder supply device according to an embodiment.

FIG. 2 is a perspective view showing a first chamber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body container 2 Partition plate 3 Hollow tube 4 Gas inlet 5 Gear feeder 6 Stirring blade 7 Powder inlet 8 Tooth groove

Claims (3)

[Claims] 1. A main body container in which the inside is maintained at a constant pressure by flowing a gas from a gas inlet, and a certain amount of powder exists below the inside by charging the powder through a powder inlet. A weighing means provided in the main body container, wherein the powder is scooped up by a tooth tip, and the raked powder is filled in a tooth space and weighed by providing a sawtooth-shaped irregularity on an outer peripheral portion of a rotating body. Agitating means for leveling the trace of the powder present below the inside of the main body container by the measuring means; and discharging the powder measured by the measuring means from the main body container and supplying the powder to another device And a supply means for supplying the powder. 2. The powder supply device according to claim 1, wherein the powder is discharged from the main body container by a pressure difference between the inside and the outside of the main body container. 3. A partition plate for separating the main body container into an upper part and a lower part, wherein only a part of the measuring means is exposed at the upper part, and the gas inlet is provided at the upper part. The powder supply device according to claim 1 or 2, wherein