JPS6082818A - Automatic measuring method of pulverulent material - Google Patents

Abstract

PURPOSE:To make measuring time constant and to make it possible to perform accurate measurement, by correcting the actual time of the total input, which is the sum of the input from a large input gate and the input from a small input gate by the control of the input time from the large input gate. CONSTITUTION:Input to a measuring tank 7 of pulverulent material is performed through a large input gate 5 and then through a small input gate 6, and a specified amount of the pulverulent material is measured. The actual input time through the gates 5 and 6 at the time of measurement is measured. The preset total input time, which is the sum of the preset input times of the gates 5 and 6, is compared with the measured actual total input time. The input time of the pulverulent material from the gate 5 at the time of subsequent measurement of the pulverulent material is controlled based on the comparing operation, and the correction is performed so that the actual total input time becomes the preset total input time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic method for weighing powder and granular material that can be carried out with high efficiency and high precision.

When weighing granular chemical fertilizers, resin pellets, grains, and other granular materials with low adhesion and cohesion, automatic weighing devices such as gravity feed type weighing machines are used. These automatic weighing devices are required to have high measurement accuracy, and for this reason, conventionally, after charging a large part of the target amount, for example, approximately 2θ%, of powder and granules into the weighing tank from the large input gate, 4. A method has been adopted in which the target amount is precisely weighed by adding small amounts at a time through a charging gate.

On the other hand, when an automatic packaging device is used as a means for packaging powder and granule weighed by an automatic powder weighing device, it is necessary to operate the automatic weighing device a predetermined number of times at a predetermined time. However, since the physical properties of powder and granular material such as particle size distribution and fluidity change, the speed at which the powder and granular material flows into the weighing tank changes, and the weighing time also changes. As a result, it becomes difficult to use the automatic packaging device. At the same time, the problem of a decrease in the weighing capacity of the weighing device due to changes in the physical properties of the powder and granules tends to occur.

The inventors of the present invention have conducted various studies in order to solve the above-mentioned problems regarding weighing time and weighing accuracy in weighing devices having large and small input gates. We have discovered a method that makes it possible to keep the weighing time constant and perform highly accurate weighing by correcting the total actual input time, which is the sum of inputs, by controlling the input time of the large input gate. Reached.

The present invention will be explained in detail below.

The automatic weighing device used in the present invention includes a measuring tank for weighing powder and granules, a large input gate for charging the powder and granules into the measuring tank, and a large input gate that also allows the powder to be fed into the measuring tank although the flow rate is small. It has a small input gate to input the body. The relationship between the progress of powder and granule weighing by this weighing device and the operating status of each gate, etc. is explained in the first section.
As shown in the figure.

The first weighing starts with the opening of the large input gate or both input gates, followed by a preset time t or a time corrected by the method described later, ・--- The gate is closed, and the small input gate is closed instead. Start charging only from the charging gate, and close the small charging gate when the powder and granular material in the measuring tank reaches a predetermined amount. Then, after a stabilization period, weigh the
After corrective charging or the like is performed as necessary, the powder or granular material is discharged from the measuring tank, and a second measurement is started in the same manner. In the present invention, the charging times t1 and t2 from the large charging gate and the small charging gate are defined as the large charging time and the small charging time, respectively. Including cases where there are.

In the present invention, when weighing the powder or granular material, a large charging time t1, a small charging time t2, and a total charging actual time t, which is the sum of both charging times, are measured, and the total charging actual time t is determined by one weighing operation. Compare and calculate the actual full-throttle time t and the set full-throttling time T so that the full-throttle set time T is set in advance to be suitable for finishing within the time, and based on this calculation, the large-throttle time 1 ．．
The subsequent injection of powder and granular materials is performed by controlling the Therefore, in order to efficiently correct the total input actual time t by t1 control, it is necessary to make the input speeds from both gates as uniform as possible during implementation of the present invention. Incidentally, the total injection setting time Tl-1 may be a single time or may have a range from the minimum value Tm1n to the maximum value Tmax as shown in FIG. In addition, it is preferable to measure, calculate, and correct the large input time t1 for each measurement in order to adapt to changes in the physical properties of the powder or granular material, but in some cases, the above correction may be performed for multiple measurements, Various methods are also possible, such as based on the average of each input time.

Furthermore, in order to correct the time required from weighing to detection, weighing is performed multiple times during charging from the small input gate, and the time required for the powder to reach a predetermined amount is predicted from the weighed value, and the actual weighed value is calculated. It is preferable to finish the injection from the small injection gate before indicating the Pfr determination, and therefore the small injection time t2
It is also desirable that the preset minimum injection time be 12 or more.

Here, FIG. 2 is shown as an example of a block system diagram showing a method of controlling each injection time according to the method of the present invention, including control of small injection times.

After the input from both input gates is completed, first, the short input time t
2 is compared with the minimum small injection time T2, and when Tz>t2, the large injection time is shortened, and t1'' calculated by the formula is taken as the large injection time for measuring the notch.

Furthermore, when T2≦t2, next is the actual full-throwing time t and the set full-throwing time T (in the figure, T is Tmin to Tmax
(shown an example with a range of i) and Tm sat n
) At the time of t, calculate 1+=1+--G, shorten the large input time t1 to tI'', and
max (When t, calculate 1+=1+10- to extend the large injection time t1 to Il+, and when Tm1n≦t≦Tmax, perform the next weighing without correcting the large injection time t1. .

Next, an example using the method of the present invention will be explained based on FIG. 3, which is a schematic diagram of an apparatus employing the automatic weighing method of the present invention.

In the figure, l is a service hopper, λ is a powder supply port, and 3
is the gate, ≠ is the volume tank, j is the large input gate, Otsu is the small input gate, 7 is the measuring tank, za is the constant volume correction input device,
2 is a correction cell, 10 is a load cell for measuring the measuring tank, l/ is the lower lid of the measuring tank, and /2 is a gate for the large flow path.

In this device, powder and granules are fed from the powder supply loco, and gate 3 is opened to open the service hopper l gate! , is charged into the meter tank 7 through the small input gate t. Both of these inputs)
, + has a structure as shown in Figure ≠, and the large input gate has a small hole a, and when a small amount is input, the input gate B is opened and the small hole is opened. Input is made through a. Therefore, when charging a large amount of powder or granular material at the start of measurement, open both input gates (J, &), input for a predetermined large input time t1, and then turn the large input gate to input a small amount. The closed small charging gate B is opened by shifting it from the position of the small hole ja, and when a predetermined value set lower than the guaranteed value of the powder or granular material is reached, the small charging gate 6 is closed to stop charging. Therefore, in the examples shown in Figures 3 and ≠, the small input gate according to the present invention is precisely composed of a combination of the small hole ja and the small input gate B, but in general, the small input gate is different from the large input gate. It is possible to adopt various forms, such as configuring it as a completely independent mechanism. Here, the next large input time t1 is calculated using the block system diagram in FIG. 2 so that the total input actual time t actually measured becomes the total input set time T.

On the other hand, the powder and granular material in the weighing tank 7 is weighed after a certain stable period of time after being charged, and this weighed value is compared with the guaranteed value to calculate the number of times the powder and granular material is corrected by the correction square. Powder and granular material is charged into the measuring WJ7 using a constant volume correction feeding device. Then, when the powder or granular material is weighed in an amount equal to or greater than the guaranteed measurement value, the lower lid of the measuring tank is opened and the granular material is discharged. After that, the lower lid l/ of the measuring tank is closed, and the large injection time tl calculated previously is
The next input is started based on the VC.

Note that the actual full-feeding time t at the time of the first weighing is the full-feeding set time T, and the small-feeding time t2 is the minimum small-feeding time 72.
In order to achieve the above, automatic metering is started after the flow rate of the powder and granular material from the large input gate j is controlled in advance so as to be suitable by adjusting the opening degree of the large channel gate 1.2. Goo for the large flow path)
The opening degree of /U usually does not change during continuous automatic weighing.
・If the physical properties of the powder or granular material have changed significantly and cannot be handled by controlling only the large input time 1+, automatically or manually adjust the opening degree of the gate 12 to 1 (adjust it again). Start weighing.

In this way, the automatic weighing method of the present invention enables quick and predetermined time measurement by correcting the total input real time, and at the same time maintains the needle foot accuracy to a significantly high level even when the physical properties of the powder or granules change. Be able to maintain it. In particular, when packaging four quantities of powder or granular material using an automatic packaging device, the fact that the weighing time is constant is an extremely outstanding feature from an industrial perspective.

The method of the present invention described above is not limited to the above-mentioned example as long as it does not go beyond the scope of the invention, and various flexible devices, modifications, and combinations with other methods are possible. For example, it is possible to volumetrically charge powder or granular material of about 0% before starting to charge the powder or granular material from the large charging gate, and then to start charging from the large charging gate or the small charging gate according to the method of the present invention. This is preferable in order to shorten measurement time.

[Brief explanation of drawings]

Figure 1 is a diagram showing the relationship between the progress of powder and granule weighing and the operating state of each gate (the part marked 0 in the figure is the operating state), and Figure 2 is a diagram showing the control method for each input time according to the method of the present invention. FIG. 3 is a schematic diagram of an apparatus employing the method of the present invention, and FIG. 3 is a perspective view of the large and small input gates of the apparatus shown in FIG. 3. L...Service hopper, K...Powder supply port, 3
...Coo), ta...volume tank,! ...Large input gate, B...Small input gate, 7...Measuring tank,
/2...For gates for large flow channels Patent attorney Representative for Mitsubishi Chemical Industries, Ltd. Patent attorney Hase - (and 7 others) Akira 1 Zui 2 A3 Figure 4 Nagi

Claims (1)

[Claims] (1) In an automatic weighing method for powder and granular materials using an automatic weighing device having a large input gate, a small input gate, and a measuring tank, the actual time of inputting the powder and granular materials into the weighing tank from the function gate is measured, Compare and calculate the total input time, which is the total input time of both gates set in advance, with the measured total input time of both gates, and then calculate the total input time from the large input gate when weighing powder and granules. An automatic weighing method for powder and granular material, characterized in that the powder and granular material charging time is controlled based on the calculation, and the actual total charging time is corrected so that it becomes the set total charging time.