JPH03246422A - Weighing device for powder - Google Patents

Abstract

PURPOSE:To weigh the powder with high accuracy by generating desired negative pressure in a powder weighing part through the operation of a sucking means and sucking the powder from the powder storage tank to the powder weighing part. CONSTITUTION:When the air in the powder weighing part 3 is sucked in through a suction path 10 and a filter 2 by the sucking means 1 while an opening/closing selector valve 8 is closed, negative pressure is generated in the weighing part 3 and the powder 7 is sucked in the weighing part 3 from the powder storage tank 4. The sucked powder 7 is cut off by the filter 2 so as not to flow in the path 10, and stacked in the weighing part 3 in order at the lower part from right near the filter 2. At this time, the quantity of the powder 7 sucked in the weighing part 3 corresponds to the negative pressure generated in the weighing part 3 corresponding to the suction force of the means 1. Then the sucking operation of the means 1 is stopped to generate positive pressure in the weighing part 3 and when the selector valve 8 is opened, the powder 7 which is sucked in the weighing part 3 is discharged to a container 11 through the selector valve 8 and a powder exit 9.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a powder measuring device, and more particularly to a powder measuring device that can accurately and quickly weigh powder.

Conventionally, Not, but After.

<Prior Art> Unlike liquids, powders are easy to handle and difficult to accurately measure in predetermined amounts. Powders are usually measured by methods that use measuring devices or tools such as hoppers, packets, or spoons. However, especially when it is required to measure a predetermined amount with M density, it has not been possible to measure with sufficient precision using these conventional methods. Therefore,
JP-A-59-182317 discloses a cylindrical quantitative sampling machine with one end open and the other end connected to a suction/discharge means via a filter, as a device for sampling a fixed amount from accumulated powder. A powder quantitative sampling device has been proposed.

<Means to be Solved by the Invention> However, even with the device proposed in JP-A-59-182317, it is still not possible to measure powder with sufficient accuracy, and the device cannot measure powder with sufficient accuracy. Since the quantitative sampling machine is moved while suctioning and the powder is transported to the desired position, it is not possible to arbitrarily select the installation location of the device and the distance the powder is moved, so it can be moved to the desired position. There was a problem with not being able to move.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a powder measuring device that can solve the problems of the conventional devices and measure powder with high accuracy, for example, ±1%.

Means for Solving the Problems> In order to solve the above problems, the present invention includes an inflating means, a powder storage tank having an open part, -1 connected to the suction means via a filter, and a powder measuring section comprising a pipe whose end communicates with the powder outlet through an on-off switching valve, and a branching section disposed between the powder measuring section and the on-off switching valve; The powder storage tank and the powder measuring section are in communication with each other,
activating the suction means to generate a desired negative pressure within the powder measuring section to suck the powder from the powder storage tank to the powder measuring section;
After a predetermined period of time has elapsed, the operation of the suction means is stopped and the on/off switching valve is opened to discharge the powder sucked into the powder measuring section from the powder outlet. It provides:

Further, it is preferable that the suction means and the filter are communicated through an on-off switching valve.

Furthermore, it is preferable that the powder measuring section and the powder storage tank are communicated via an on-off switching valve.

Hereinafter, the powder measuring device of the present invention will be described in detail based on an embodiment of the powder measuring device of the present invention shown in FIG.

Figure 17J1 shows an embodiment of the powder measuring device of the present invention. It is a means. Reference numeral 4 denotes a powder storage tank that communicates with the powder measuring section 3 and the branching section 5 via a flow path 6 and stores the powder 7 therein. 8 is the branch part 5 on the powder outlet 9 side of the powder metering 3
This is an on-off switching valve located further down.

In this powder measuring device, the suction path 10 and the filter 2 are
When the air inside the powder measuring section 3 is sucked through the powder measuring section 3 , the inside of the powder measuring section 3 becomes negative pressure, and the powder 7 is sucked into the powder measuring section 3 from the powder storage tank 4 . The suctioned powder is blocked by the filter 2 and does not flow into the suction path 10 side, but is sequentially stacked downward from the vicinity of the filter 2 in the powder measuring section. At this point, the amount of powder sucked into the powder measuring section 3 is an amount corresponding to the negative pressure inside the powder measuring section 3 generated in accordance with the suction force of the suction means 1. It is sucked into the measuring section 3. Next, when the suction operation of the suction means 1 is stopped and the inside of the powder measuring section 3 is made to have a positive pressure, and the on-off switching valve 8 is opened, the powder sucked into the powder measuring section 3 is passes through the on-off switching valve 8 and the powder outlet 9 to the container 11
is discharged.

In the measuring device of the present invention, the powder 7 stored in the powder storage tank 4 is collected by a combination of the internal volume of the powder measuring section 3, the suction force of the suction means, the suction time, etc. through the series of operations described above. A predetermined amount corresponding to the powder can be put into a container disposed below the powder outlet.

If the internal volume of the powder measuring section 3 is appropriately selected according to the powder to be measured, the desired amount of powder can be measured with high precision, for example, ±1% precision, and with high efficiency. It can be measured with. Furthermore, by appropriately controlling the suction force and time of the suction means 1, it is possible to adjust the amount of powder remaining in the powder measuring section 3 and measure a desired amount of powder.

The tube constituting the powder measuring section is not particularly limited, but for example, it is made of a material such as fluororesin such as Teflon, urethane resin, metal, glass, etc. and has an inner diameter of 1 to 6 mm, preferably about 4 mm. It is. This tube is
Depending on the type and amount of powder to be measured, there may be thick and short, thin and long, spherical, funnel-shaped,
Tubes having various shapes, such as a coiled (helical) shape, can be used as appropriate. In particular, Teflon (2) is preferable because it does not adsorb the powder that is sucked into the powder measuring section.

The filter 2 is made of a filter material through which powder does not pass through due to the suction operation of the suction means 1. The filter medium to be used may be appropriately selected depending on the particle size, type, etc. of the powder to be measured, and is not particularly limited. For example, when measuring terephthalic acid having an average particle size of 130 to 140 μm as a powder, a 0.45 μm filter may be used.

In addition, in this embodiment, if an on-off switching valve is disposed in the middle of the suction path 10, and is opened when the suction means 1 performs the suction operation, and closed when the suction operation of the suction means 1 is finished, the powder can be This is preferable since it is used to prevent backflow into the body reservoir.

Furthermore, an on-off switching valve is disposed in the middle of the distribution channel 6, and is kept open when the suction means 1 sucks the powder and moves the powder from the powder storage tank 4 to the powder measuring section 3. When a predetermined amount of powder is sucked into the powder measuring section 3 and the on-off switching valve 8 on the powder outlet side is opened, if it is closed, the powder in the powder storage tank will be removed. Powder outlet 9 due to its own weight
This is preferable because it can prevent it from flowing down.

The powder storage tank 4 has an open part so that the powder stored in response to the suction of the powder by the suction means passes through the distribution channel 6, passes through the branch part 5, and is smoothly sucked into the powder measuring part. be. The opening may be provided, for example, by providing a hole or the like in the upper part of the powder storage tank. In addition, in the powder storage tank, in order to make the retention state of the powder uniform in the powder storage tank and to smooth the movement of the powder according to the suction of the powder to the powder measuring section, there is a The powder is stored in the powder storage tank 24 by a means for stirring the powder, for example, as shown in FIG. It is best to level out the powder evenly. Further, as shown in FIG. 3, a plurality of blades 27
It is preferable that the rotary shaft 28 equipped with the powder is rotated by the motor 29, and the powder stored in the powder storage tank is evenly distributed by the plurality of blades 27. It is preferable if the powder in the powder storage tank can be evened out in this manner, since the powder can flow smoothly from the powder storage tank to the powder measuring section through the distribution path.

In this measuring device, the on-off switching valve 8, the on-off switching valve provided in the middle of the suction path 10, and the on-off switching valve provided in the middle of the distribution path 6 are integrated and controlled to open and close each of them. Powder can be weighed with high efficiency and precision, and if the series of on-off switching valves are solenoid valves and their opening/closing operations are controlled by appropriate means, powder weighing and/or Alternatively, charging into the container can be automatically controlled, which is advantageous for automation of weighing.

Furthermore, an on-off switching valve is provided in the middle of the distribution path that communicates the powder storage tank with the branch part, and the switching valve controls the flow of the powder sucked and distributed from the powder storage tank to the powder measuring part. You can also do it.

Further, in the embodiment shown in FIG. 1, the branch part 5 that connects the powder meter [4 and the powder measuring part 3] has a 17-shape, but the present invention is not limited to this. For example, as shown in FIG. 4, in a T-shaped branch 45, a distribution channel 46 through which powder flows from the powder storage tank 44 and a powder measuring section 43 are connected in a substantially straight line, and the powder is An inverted flow path 50 connected to the outlet 49 connects to the T-shaped branch 45.
They may intersect at right angles or approximately at right angles. This is preferable because it is possible to prevent the powder from being diverted to the distribution path 50 side at the branch portion 45 when the powder is sucked, and the powder can be measured with higher accuracy.

Furthermore, as shown in FIG. 5, it is preferable to arrange the on-off switching valve 8 as close as possible to the branching part 5 and below it, since this can prevent the powder from being separated. Alternatively, if a powder blocking valve is provided, the powder discharged from the powder measuring section can be smoothly discharged from the powder outlet, which is advantageous.

Furthermore, the length of the distribution route 6 is not particularly limited, and even if the installation location of the powder storage tank and the location where powder is measured and added are far apart, the length of the distribution route 6 can be extended to any length. Adaptable. The same applies to the distribution route 9.

The powder measuring device of the present invention is not limited to the single device shown in FIG. 1, but for example, as shown in FIG. It is also possible to have a configuration having the following.

In the measuring device shown in FIG. 6, a plurality of suction paths 10a to 101 communicating from one suction means 1 are connected to a plurality of powder measuring units 3a to 31 via corresponding filters 2a to 21, respectively. Each is connected. The plurality of powder measuring units 3a to 31 are connected to distribution channels 68 to 61, respectively.
It is communicated with the powder storage tank 4 by. Open/close switching valves 88 to 81 are provided on the powder outlet sides of the powder measuring units 3a to 31, respectively.

In the device shown in FIG. 6, the powder stored in the powder storage tank 4 is weighed in a predetermined amount by the same operation as the device shown in FIG. It is possible to discharge the force from the seven. Therefore, the on-off switching valve 8a~
By appropriately controlling the opening/closing operation of 81, for example, a plurality of containers can be placed directly below the powder outlets 98 to 91,
For example, by moving parallel B in the direction of arrow 13 and controlling the opening/closing operation of the on-off switching valves 88 to 81, powder suction, and metering operation as appropriate, containers in rows A, B, C, and D can be moved. Different amounts of powder can be added to each.

Furthermore, if the above-mentioned control is applied to the individual containers in each of the A%B, C, and D rows in a pure manner, different amounts of powder can be added to each container in the same row.

Furthermore, although the apparatus shown in FIG. 6 has a configuration in which a powder storage tank is shared, this structure has been changed to include a plurality of powder storage tanks, and each powder storage tank stores a different type of powder. If a powder measuring section is connected to each powder storage tank, each powder measuring section can be controlled in the same manner as shown in Fig. 1 to measure the powder stored in the powder storage tank. By adjusting the discharge of powder from the powder outlet, a mixture consisting of a desired powder type and mixing ratio can be prepared.

Moreover, if the internal volumes of the plurality of powder measuring sections are different from each other, different amounts of powder can be measured.

<Example> Hereinafter, the present invention will be described in more detail with reference to Examples of the present invention.

(Example 1) The powder shown in FIG. 1 was equipped with a tube having an inner diameter and length shown in Table 1 as a powder measuring section, and a tube having an inner diameter, type, and length shown in Table 1 as a distribution route. Using a weighing device,
By varying the amount of terephthalic acid (average particle size: 135 μm) to be measured, a negative pressure knee of 550 ++ m was applied by suction means.
Hg, positive pressure: 0. Weighing was performed at a rate of 5 to 1.0 kg/cm to determine the range of the amount of terephthalic acid powder that could be measured. The results are shown in Table 1.

In addition, terephthalic acid powder was measured at
When the weight of each weighed terephthalic acid powder was measured, the following results were obtained.

1st time 10.691g 2nd time 10.622g 3rd time 10.917g 4th time 10.762g Average weight 10.748g Standard deviation 0.1263 CV (relative error) 1.2% (Example 2) When the inner diameter is 2.5mm , a measuring device (with the structure shown in FIG.
(horizontal), by suction means, negative pressure knee 550mm
Hg (operating time: 10-20 seconds), positive pressure: 0. 5～
At 1.0 kg/cm, terephthalic acid powder (average particle size: 1
35 μm) each number of times shown in Table 2, the weight of the obtained terephthalic acid powder was measured, and the average weight, standard deviation, and accuracy were determined. The results are shown in Table 2. Table 2 also shows the results (vertical) obtained using the apparatus having the structure shown in FIG.

Table <Effects of the Invention> The measuring device of the present invention can quickly measure powder with high accuracy, for example, with an accuracy of ±1%. In addition, the installation location of each element that makes up the device, such as the powder storage tank, suction means, powder measuring section, etc., can be arbitrarily selected depending on the surrounding environment, and furthermore, each element can be easily controlled automatically. , which is advantageous for automation of weighing.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the powder measuring device of the present invention, FIGS. 2 and 3 are diagrams showing examples of stirring means provided in the powder storage tank, and FIGS. 4 and 5. and FIG. 6 are schematic diagrams showing another embodiment. Explanation of symbols 1... Inflating means, 2... Filter 3... Powder measuring section, 4... Powder storage tank, 5... Branching part, 6... Distribution route, 7...・Powder, 8... Open/close switching valve, 9... Powder outlet, 10... Suction route, 11... Container FIG, 1 FIG, 2 FIG, 3 5 FIG, 4 FIG5 FIG6

Claims (4)

[Claims] (1) Consists of a suction means, a powder storage tank having an open part, and a pipe whose one end is connected to the suction means via a filter and the other end communicates with the powder outlet through an on-off switching valve. a powder measuring section, the powder storage tank and the powder measuring section are communicated with each other at a branching section disposed between the powder measuring section and the on/off switching valve, and the suction means is actuated. A desired negative pressure is generated in the powder measuring section to suck the powder from the powder storage tank to the powder measuring section, and after a predetermined period of time, the operation of the suction means is stopped and the on/off switching valve is opened to suck the powder. A powder measuring device characterized in that powder sucked into a body measuring section is discharged from a powder outlet. (2) The powder measuring device according to claim 1, wherein the suction means and the filter are communicated through an on-off switching valve. (3) The powder measuring device according to claim 1 or 2, wherein the powder measuring section and the powder storage tank are communicated via an on-off switching valve. (4) A powder measuring device formed by combining a plurality of powder measuring devices according to any one of claims 1 to 3.