JP2627943B2 - Method and apparatus for measuring flow rate of granular material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for measuring the flow rate of a granular material which measures the flow rate of a granular material during transportation without stopping the flow.

(Prior Art) It has been considered to measure a flow rate of a granular material during transportation, control a transportation amount based on the flow rate value, and manage a process.

Conventional flow measurement devices that measure the flow rate of granular materials during transportation include a direct measurement method that measures weight using a weighing device and an indirect measurement method that calculates the flow rate from indirect characteristic quantities. There are a scale, a belt scale, an annular balance type flow meter and the like, and the latter includes a drop impact type flow meter and a rotary torque type flow meter.

One of the direct flow rate measurement methods, hopper scale, measures the flow rate of a granular material in batches by installing a hopper scale in the middle of the transportation route of the granular material. Since the flow rate is calculated by measuring the weight of the granular material to be charged, the apparatus is large and the flow is intermittent.

In addition, the flow rate measurement by the belt scale is to float the weight of the granular material transported by the belt conveyor on the rollers and the entire conveyor that supports the belt conveyor,
Various equilibrium devices balance the load applied to them, measure the weight per unit length of the granular material on the belt, and use it as the instantaneous flow rate. Since it is not a batch type, the flow of the granular material is intermittent. Nevertheless, the scale of the device is the same as that of the hobber scale.

In addition, the annular balance type flow meter is a series of powders having an annular balance structure in which a fulcrum is provided at both ends on the diameter of an annular transporter loop conveyor having a horizontally rotating disk, an inlet is provided on one side, and an outlet is provided on the other side. It is a type flow meter. The powder particles flowing in from the inlet are transported half way around by the rotation of the disk, dropped and discharged at the outlet, and transported along half the circumference of the disk by a load cell provided at right angles to the diameter passing through the fulcrum. A signal proportional to the weight of the body is transmitted, and an instantaneous flow rate signal is transmitted by multiplying the weight signal by an electric signal corresponding to the number of rotations of a rotating oscillator mounted on the rotating shaft of the disk.

However, this annular balance type flow meter is not different from the former two in that the device is large-scale.

On the other hand, a drop impact type flow meter, which is one of the indirect measurement methods, calculates the instantaneous flow rate from the component force of the impact force applied by a granular material passing through a rectifier from a certain height and hitting an inclined plate. However, it is expensive, the equipment is large, and the type of granular material is limited, the falling distance of the granular material, and thus the installation device for the inclined plate is limited, and the flow rate depends on the granular material. Since the display changes, there is a problem that correction is required.

Another type of rotary torque type flow meter is that when powder is supplied from above to a rotating inner plate with a guide blade, the powder is accelerated and discharged by centrifugal force, and at the same time, is inversely proportional to the mass flow rate of the powder by Coriolis force. Since the force is given to the rotating inner plate,
The instantaneous flow rate is obtained from the moment applied around the center of the rotating inner plate. This flow meter is also no different from the above flow meter in that the device is large-scale.

By the way, in many cases, the transportation of powders and granules is carried out by gravity gravity, and the flow meter can be installed in a small space without interrupting the flow in the middle of inclined transportation, etc. Although it is desired to measure the flow rate by incorporating the above, it is very difficult to incorporate the conventional measuring device in the middle of the transport pipeline and at a desired position or to provide it at many positions because many of the conventional measuring devices described above are large-scale. Therefore, in reality, it is impossible to control flow rate or process control based on the flow rate in the granular material processing process as desired or fine control.

(Object and Configuration of the Invention) The present invention has been made in view of the above points, and provides a method and an apparatus for measuring a flow rate which can be incorporated in a transportation pipe in a small space without stopping the flow of a granular material. In order to achieve this object, in order to achieve this object, a plurality of measuring pipes are provided in series with the flow of the granular material in the transport pipe and are mechanically separated from the transport pipe and the measuring pipe, and the powder flowing inside each measuring pipe is provided. The weight of the granules is detected, and the time taken for the same shape to move in the two tubes is measured by focusing on the portion where the shape of the change in weight is the same, and calculated based on the length of this tube, The flow rate was determined, the flow rate of the powder was determined, and the flow rate was calculated from the weight per unit length of the measuring tube.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of an apparatus for carrying out a method for measuring a flow rate of a granular material according to the present invention.

The measuring pipes 2 and 3 of the same diameter are mechanically separated from the transport pipe 1 in series in the middle of the inclined transport pipe 1 for transporting the granular material in the direction of the arrow, and the measuring pipes are also mechanically separated from each other. And covered with a flexible cover 4 so that the powder does not leak out from between the tubes.

The measuring tubes 2 and 3 are separately connected to load cells 5 and 6, respectively, so that the weight of the granular material in the tubes can be measured.

Reference numerals 7 and 8 denote A / D converters for amplifying the weight signals output from the load cells 5 and 6 by the amplifiers 10 and 11, respectively, and then converting the digital signals into digital signals. The delay time of the weight signal is obtained, the flow velocity of the granular material is calculated using the center pipe distance between the two measuring pipes 2 and 3 along the flow path, and the weight per unit length of the measuring pipe and the flow rate thus calculated are calculated. Is calculated to obtain the flow rate.

Next, a procedure for measuring the flow rate by the flow rate measuring device having the above configuration and the operation of the device will be described.

When the powder is flowing in the direction of the arrow, the weight signals A and B output from the load cells 5 and 6 are as shown in FIG. The powder flowing through the measuring tube 2 must be a measuring tube 3
Therefore, although there is a slight difference between the two signals, the waveforms of the two weight signals A and B are very similar.

Therefore, the arithmetic circuit 9 calculates the two weight signals A and B.
The delay time τ _m is obtained from the waveform of the above equation, and since the center distance between the measuring tubes 2 and 3 is known, a method called a cross-correlation function is used to obtain the flow velocity of the granular material.

In general, the cross-correlation function R _xy (τ) between two signals x (t) and y (t) can be expressed by the following equation.

Therefore, the waveforms of the two weight signals A and B shown in FIG. 2 are sampled for each Δt, A / D converted, and Wa _(i) ,
It is stored in the memory as _{Wb (i)} . Where W
_{When a} cross-correlation function R _(k) between m pieces of continuous data for each of the data strings of _{a (i)} and _{Wb (i)} is obtained, Becomes Varying wherein the k 0, 1, 2 ... and so R _(k) is at the k = k _m corresponding to the delay time tau _m will take a peak, from τ _{m =} Δt · k _m The delay time τ _m is obtained.

When the distance between the centers of the measuring tube 2 and 3 is L, the average flow velocity of the granular material is determined by the L / tau _m. On the other hand, weight signals A and B
From the weight signal A or the weight signal A or B.
Is G = × / l (where 1 is the average of the pipe lengths of the measuring tubes 2 and 3).

 Thus, the flow rate of the powder can be determined.

Although two measuring tubes are used in the above embodiment, any number of two or more measuring tubes can be used in the present invention.
In the present embodiment, the weight of the granular material in the measuring tube measured by the load cells 5 and 6 may be a vertically downward component or a component perpendicular to the tube wall, and the force component to be measured is arbitrary. Orientation is acceptable.

(Effects of the Invention) As described above, in the present invention, a plurality of measuring tubes are provided in series with the flow of the granular material in the transport tube so as to be dynamically separated from the transport tube and the measuring tube, and each of the calculation tubes is provided separately. Detect the weight of the granular material flowing inside, calculate the flow velocity of the granular material by paying attention to the part where the form of the weight change is the same, and calculate the flow rate from the weight per unit length of the measuring pipe separately obtained. With this configuration, the flow meter can be incorporated in a part of the transport pipe in a small space, and the flow rate can be measured without stopping the flow of the granular material. Therefore, the influence on the powder treatment process and the disturbance are small.

In the present invention, the flow rate can be obtained regardless of the type of the granular material.

In addition, since the impact force is not applied to the measuring section, the flowmeter can be calibrated by static actual penetration calibration, so that the calibration operation is simplified, and there is no measurement error due to the fluctuation of the impact force.

In addition, the flow rate and the integrated value of the granular material can be continuously measured.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of one embodiment of an apparatus for implementing the method for measuring the flow rate of a granular material according to the present invention, and FIG. 2 shows a weight signal in the apparatus for performing the method for measuring the flow rate of a granular material of the present invention. It is a graph. 1 ... Transport pipe, 2,3 ... Measurement pipe, 4 ... Cover, 5,6 ... Load cell, 7,8 ... A / D converter, 9 ... Operation circuit, 10, 11 ... Amplifier

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ryo Hiruma 2-127 Asama-cho, Omiya City, Saitama Prefecture (72) Inventor Rokuo 3-15-11 Baba, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture JP-A-64-91019 (JP, A) JP-A-59-48621 (JP, A) JP-A-63-167221 (JP, U)

Claims (3)

(57) [Claims] At least two parts having the same diameter arranged in such a manner that a part of a powder transporting body is cut and a downstream side thereof is cut in series with the transporting pipe and is mechanically separated from each other, but is arranged so that there is no leakage of the granular material. The weight of the granular material flowing in each of the measuring tubes is detected as a measuring tube, and in the two measuring tubes, the time required for a portion where the detected change in weight is substantially the same to move through the two measuring tubes is measured. A method of measuring the flow velocity of a granular material from the length of two tubes. 2. A method for cutting a portion of a powder transporting body, and cutting at least two of the pipes at a downstream side thereof in series with the transporting pipe and mechanically separating each other but without leakage of the powder. The weight of the granular material flowing through each of the measuring tubes as a measuring tube having a diameter is detected, and the time when the change in the detected weight of the two measuring tubes becomes substantially the same is measured by moving the two measuring tubes. A method of measuring the flow velocity of a granular material from the flow of two pipes, measuring the weight of the granular material per unit by a measuring pipe, and obtaining the flow rate of the granular material from the measured value. 3. A part of the powder transporting body is cut, and arranged downstream thereof in series with the transporting pipe and mechanically cut off from the transporting pipe, but is arranged so as not to leak the particulates. At least 2
Two measuring tubes having the same diameter, weight detecting means for detecting the weight of the granular material flowing in each of the measuring tubes, and a portion where the shape of the change in the weight detected for the two measuring tubes becomes the same. Calculating means for calculating the flow rate of the granular material from the moving time, calculating the flow rate and the weight of the granular material per unit length of the measuring tube, and calculating the flow rate of the granular material. Flow rate measuring device for granular material.