JPH0812091B2 - Granule flow meter - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter for measuring the flow rate of powder or granular material, and more particularly to the flow rate of cereals falling from the outlet of a powder or granular material supply device having a hopper at the bottom of a storage tank. The present invention relates to an impact type flow meter for measuring.

2. Description of the Related Art There are two methods for measuring the amount of powder or granular material transported, that is, the flow rate, that is, a method of using a weighing device and a method of using an impact type flow meter as an object of the present invention. In the former method, the weight of the granular material is measured, so that the measurement accuracy is high regardless of the type and shape of the granular material. However, the mechanism is complicated and expensive. Furthermore, since a constant weighing period is required, it is not possible to measure with a fast response time.

On the contrary, in the method of using the impact type flow meter, the granular material is applied to the detection plate, and the flow rate is electrically calculated from the impact generated on the detection plate at that time. This flow meter has a fast response speed and is used when continuously measuring the flow rate of powder or granular material or when controlling so that the flow rate is always maintained at a predetermined value. However, since this impact type flow meter is an indirect measurement, there is a limit to the accuracy that can be obtained due to various factors.

In order to improve the measurement accuracy in this type of flow meter, a gutter or a cloth shooter may be attached to the discharge port of the powder or granular material supply device so as to prevent the powder or granular material from falling laterally. Further, in some cases, when a powder or granular material temporarily stays discontinuously or adheres on the detection plate, a vibration mechanism for preventing this phenomenon is incorporated in the detection plate.

Problems to be Solved by the Invention In many cases, measurement using an impact type flow meter is continuously performed for a long time. Therefore, if there is a slight error in the indicated value of the flow rate, the integrated value of the supplied powder or granular material finally gives a large difference, which is a serious problem in practical use.

The impact applied to the detection plate is the product of the momentum generated by each falling powder or granule hitting the detection plate, that is, the product of the weight of each powder or granular product and the change in velocity (including the change in traveling direction) caused by collision. Corresponds to the statistical value of the sum.

On the other hand, the flow rate of the granular material is usually expressed by the weight of the granular material transported in a unit time. Comparing this flow rate with the above-mentioned impact, the latter contains an extra change in speed, which is a so-called indirect measurement. Therefore, even if similar granular materials having slightly different shapes or densities are flowed at the same flow rate, a difference is often observed in the indicated value of measurement. Furthermore, even for the same powder or granular material, when the flow rate is changed significantly, there is no perfect proportional relationship (linearity) between the indicated value and the actual value, and deviation from a straight line is also recognized. ing.

The above-mentioned error is caused by the difference in the detection sensitivity of the detection system even if the incident conditions are the same when the types of the granular material are different.
The following factors are considered to affect the sensitivity. That is, (i) the deviation of the incident position with respect to the detection plate, (ii) the deviation of the incident direction with respect to the detection plate, (iii) the dispersion of the granular material, that is, the change in the velocity distribution, (iv) the change in the reflection state by the detection plate (for example, , The difference in the coefficient of restitution of the particles causes the path after reflection to be different), (v) The detection plate is not a simple impact, and the residence time when the particles move along the detection plate It also detects the gravity exerted during.

The conventional technology such as gutter exerts an effective effect on (i) and (ii), but does not work effectively on (iii) to (v). SUMMARY OF THE INVENTION An object of the present invention is to provide a powder / granular flowmeter which constitutes a detection system effective for all of the above-mentioned factors, and which is simple, inexpensive, and has a reproducible flow rate value.

Means for Solving the Problems An object of the present invention is to apply a powder or granular material falling from a powder or granular material supply device capable of varying a flow rate to a detection plate according to the present invention,
A particle-granular flow meter for converting the force applied to the detection plate into an electric signal to measure the flow rate of the powder-granular material. Further buffer plates 1 are installed in a tilted manner, the final buffer plate 1 is tilted in the same direction as the detection plate 2, and all the powder particles falling from the powder particle supplying device are received by the buffer plates 1, 1 and then dropped onto the detection plate 2. In this case, the inclination angle Θ _B of the final buffer plate 1 with respect to the horizontal plane is equal to the inclination angle Θ _{D of the} detection plate 2.
It is made larger and the detection plate 2 is provided just below the lower end of the final buffer plate 1.
This is solved by disposing the upper end of the above and providing a detection system for detecting the vertical component of the force applied to the detection plate 2.

When the configurations of claims 2 to 5 are added to the above configuration, the obtained effect is further improved.

Operation The configuration of the present invention provides the following effects: (i) Even if the flow rate of the granular material changes due to the function of the buffer plate itself, the falling position and the falling direction of the granular material with respect to the detection plate are made constant, and The dispersion of the speed of the powder and granules falling from the granule feeder is made constant.

(Ii) With respect to the disposition of the buffer plate and the detection plate, the difference in inclination angle between them is small, and the granular material is incident on the detection plate with a small impact and moves while sliding on the detection plate. The inclination angle of the detection plate is smaller than the inclination angle of the buffer plate, and a quasi-static force is applied to the detection plate with the movement of the granular material.

From the structure according to the embodiment of the present invention, (iii) the detection plate is bent in a concave shape, and the force applied by the sliding of the powder or granular material described in (ii) is further increased.

(Iv) The buffer plate is bent in a concave shape to prevent the powder particles from diverging in parallel to the tilt axis direction.

(V) The inclination angle of the buffer plate can be changed by the fine adjustment mechanism.

Embodiment Hereinafter, the present invention will be described in more detail with reference to the drawings illustrating an embodiment.

FIG. 1 schematically shows a part of a detection unit applied in an embodiment of the granular material flowmeter according to the present invention in the simplest form. The granular material 10 falls from the outlet 12 at the lower part of the granular material supply device, and first hits the buffer plate 1 which is obliquely arranged, and then,
The granular material 10 moves along the buffer plate 1 and falls from the lower end. In this case, the upper end of the detection plate 2 is placed close to the lower end of the buffer plate 1 so that both plates 1 and 2 are inclined in the same direction.

The buffer plate 1 according to the present invention is not limited to one, but may be composed of one or more as shown in FIG. Assuming that the inclination angles of the buffer plate 1 (or the plate at the bottom when there are many buffer plates) and the detection plate 2 are Θ _B and Θ _D , respectively, as shown in FIG. It is effective to select Θ _B larger than Θ _D and make the difference between them within 20 °.

The buffer plate 1 itself has the following actions. As can be easily measured from Fig. 1, the granular material 10 has fallen from the discharge port 12
Is applied to the buffer plate 1 once, the buffer plate 1
The direction and position of the drop from the bottom end of are constant. Further, even if there is a variation in the falling speed of the powdery particles, the variation is averaged because it hits the buffer plate once. The gutter or shooter used in the prior art mentioned at the beginning often applies only the granular material that is out of the main falling direction to the wall surface and returns it in the main falling direction, so that the speed according to the present invention is made uniform. It has no effect.

Furthermore, the detection method according to the present invention is significantly different from the conventional impact type flowmeter. That is, the powder particles 10 'having a uniform speed described above are placed in the detection plate 2 while keeping the incident angle small. Under this incident condition, the impact applied to the detection plate 2 is small, and rather, when the powdery particles slide on the detection plate 2 and move, quasi-static gravity is applied. In the present invention, since the detection unit (not shown) that detects only the component of the force applied to the detection plate 2 in the vertical direction is incorporated, the flow rate is detected by using the action close to the weighing measurement. Become.

The reason why Θ _B is made larger than Θ _D is as follows. That is, if Θ _B is smaller than Θ _D , there is a possibility that a part (in some cases, all) of the granular material does not hit the detection plate (in the upper part of the granular material flow 10 'in FIG. 1). The powder is Θ _D
Is large, the detection plate will be skipped). Structure of the invention, Θ _B
As long as −Θ _D > 0 and the lower part of the buffer plate 1 and the upper part of the detection plate are close to each other, all the particles enter the detection plate 2. Further, in the incident direction with respect to the detection plate 2, powder particles are present on the detection plate 2.
Since it is larger than the angle corresponding to the direction of sliding and moving up, a quasi-static force is constantly applied to the detection plate 2.

2a and 2b show two kinds of examples in which one or more buffer plates of the flowmeter according to the present invention are formed. All buffer plates 1 are arranged in the same orientation in FIG. 2a and alternately tilted in FIG. 2b. Increasing the number of buffer plates further reduces the falling speed, prolongs the time of staying on the detection plate, and increases the detection sensitivity. 2b
The arrangement shown in the figure reduces the footprint in the lateral direction.

FIG. 3 shows an embodiment of the detector of the flow meter to which the present invention is applied. In this case, the buffer plate 1 and the detection plate 2 are slightly warped by any displacement. The warp of the buffer plate 1 is orthogonal to the tilt axis 5 and is formed in a concave shape upward in a symmetrical manner with respect to a plane passing through the center of the plate 1. Therefore, it has a function of preventing the powdery particles from diverging in the direction of the tilt axis. With respect to the warp of the detection plate 2, its function and effect will be described with reference to FIG. Further, a tilting mechanism for finely adjusting the tilt angle with the knob 3 is incorporated in the support mechanism of the buffer plate 1, and is rotatably installed on the flowmeter main body 4. The mounting method of the tilting mechanism is the third
In addition to the illustrated embodiment, the knob 3 can be installed inside the main body 4 and, once the adjustment is completed, can be installed in a place where it cannot be touched by human hands.

FIG. 4 shows an embodiment of the detection plate 2 according to the present invention.
The detector plate 2 has the dimensions used for measuring the flow rate shown in FIG. 5a. The lower half of the detection plate 2 is warped.
This warp has the effect of further increasing the quasi-static force applied to the detection plate 2 when the powder or granules leaving the detection plate 2 slide, as in the case described with reference to FIG. Therefore, the detection sensitivity is also improved.

In order to know the effect of the constitution of the present invention, the flow rates of two kinds of wheat shown in Table II were measured by using two kinds of combinations of the buffer plate and the detection plate shown in Table I. In the arrangement α according to the present invention, the lower end of the buffer plate and the upper end of the detection plate are located at the same position when projected on the horizontal plane, and H and H ′ are vertical distances shown in FIG. 1, respectively. The size of the detection plate and buffer plate is 20 x 20 cm
²

The actual flow rate is determined by weighing the weight of wheat that has flowed for a certain period of time, and the indicated flow rate for both arrangements α and β is the wheat of type A and the actual flow rate is set to about 8 t / h and the indicated value of the detector is measured. According to the flow rate value, the detector was left as it was, and the other flow rate values were measured for wheat of A type and all the flow rates were measured for wheat of B value.
The sensor of the detector is an induction coil and is arranged so as to detect the force in the vertical direction of the detection plate. The flow rate measurement was performed 5 times at each measurement point, and the average value is shown. The deviation from the average value was less than 0.5%.

FIG. 5b shows the measurement result of the arrangement β of the configuration according to the prior art. It is known from experience that the repulsion coefficient is fairly large with a difference of about 3% in the specific gravity of A and B types. With this configuration β there is a difference of about 7% in the measurement between both species of wheat. When the flow rate is changed, deviation from the straight line is also recognized.

The arrangement α of the present invention shows a significant improvement as shown in FIG. 5a, and both measured values agree with the straight line drawn in the figure within a range of about 1%.

Advantageous Effects of the Invention With the buffer plate installed in front of the detection plate, not only the drop position and the falling direction of the powder particles with respect to the detection plate are constant,
Reproducibility of measurement sensitivity is improved by evenly adjusting speed variations.

When the powder particles enter the detection plate, the buffer plate is incident at a shallow angle, so a large shock is not applied to the detection plate,
Rather, the force due to the weight when falling along the detection plate is applied. This means that it is close to the state of weighing measurement and improves the reproducibility of measurement.

The warp of the detection plate enhances the detection sensitivity, and the tilting mechanism of the buffer plate has the effect of making the reproducibility of the measurement constant, which facilitates the production and maintenance.

[Brief description of drawings]

1, a schematic cross-sectional view showing the arrangement of a detection plate and a buffer plate according to the present invention, FIG. 2, a side view showing a possible arrangement of a plurality of buffer plates, FIG. 3, an external view of a flow meter according to the present invention, FIG. 4 is a cross-sectional view showing one embodiment of the detection plate according to the present invention, FIGS. 5a and 5b, showing flow rate measurement values obtained for two kinds of wheat by two arrangements α and β of the detection system, respectively. The graph that shows. Reference symbols in the figure: 1 ... Buffer plate, 2 ... Detection plate

Claims (5)

[Claims] 1. A granular material for measuring the flow rate of a granular material by applying a granular material falling from a granular material supply device whose flow rate is variable to a detection plate and converting the force applied to the detection plate into an electric signal. In the flow meter, one or more buffer plates (1) are installed at an angle between the discharge port (12) at the bottom of the powder and granular material supply device and the detection plate (2), and the final buffer plate (1) is installed. Tilt in the same direction as the detection plate (2), receive all the powder and granules falling from the powder and granular material supply device in each buffer plate (1), drop them along the buffer plate (1), and then detect the detection plate (2). ), In this case, the inclination angle (Θ _B ) of the final buffer plate (1) with respect to the horizontal plane.
Is larger than the inclination angle (Θ _D ) of the detection plate (2), the upper end of the detection plate (2) is arranged just below the lower end of the final buffer plate (1), and the force applied to the detection plate (2) is A granular material flowmeter, comprising a detection system for detecting a vertical component. 2. The granular material flowmeter according to claim 1, wherein the lower half of the lower end of the detection plate (2) is bent upward to form a concave shape. 3. A buffer plate (1) which is orthogonal to the tilt axis (5) and is bent upward in a concave shape symmetrically with respect to a plane passing through the center of the plate (1). The granular material flowmeter according to claim 1 or 2. 4. In the case of a plurality of buffer plates (1), the respective buffer plates (1) are arranged so as to be alternately tilted in a direction intersecting with each other or tilted in the same direction, or with some displacement. The granular material flowmeter according to any one of claims 1 to 3, which is characterized by being present. 5. A tilting mechanism (5) for varying a tilt angle is incorporated in a support mechanism of a buffer plate (1), and any one of claims 1 to 4 is set. The granular material flowmeter described in.