JPH02126120A - Flow measuring instrument for granular particles - Google Patents

Abstract

PURPOSE:To perform measurement in a narrow space without stopping the flow of granular particles by providing plural measuring pipes dynamically disconnected from one another in series in a transport pipe and operating the flow rate in accordance with the weight of granular particles flowing in each measuring pipe. CONSTITUTION:Measuring pipes 2 and 3 having the same diameter as an inclined transport pipe 1 through which granular particles are transported are dynamically disconnected from the pipe 2 respectively and arranged in series on the way of the transport pipe 1, and joints are covered with a flexible cover 4 to prevent leak. Pipes 2 and 3 are connected to load cells 5 and 6 respectively independently of each other to measure the weights of granular particles in pipes. Weight signals are amplified by amplifiers 10 and 11 and pass A/D converters 7 and 8 and are inputted to an operation circuit 9. A mutual correlation function is used to obtain the delay time of two weight signals, and the distance between centers of pipes 2 and 3 along the flow passage is used to operate the speed of flowing granular particles, and it is multiplied by the weight per a unit length of measuring pipes to calculate the flow rate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a flow rate measuring device for powder and granular material that measures the flow rate of powder and granular material during transportation without stopping the flow.

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

Conventional flow rate measurement devices for measuring the flow rate of powder and granular materials during transportation include a direct measurement method that measures the weight using a scale device, and an indirect measurement method that calculates the flow rate from 5 indirect characteristic quantities.The former uses a hopper scale. , belt scales, annular balance type flowmeters, and the latter include drop impact type flowmeters and rotating torque type flowmeters.

Flow rate measurement using a hover scale, which is one of the direct flow rate measurement methods, involves installing a hover scale in the middle of the transportation route for powder and granules, and batch weighing the powder and granules being transported. Since the method calculates the flow rate by measuring the weight of the powder and granules put into the hopper each time, the device is large-scale and the flow is intermittent.

In addition, flow rate measurement using a belt scale involves floating the weight of the powder and granules being transported by the belt conveyor, the rollers supporting the belt conveyor, and the entire conveyor, and balancing the load on them using various balance devices. belt-
This is a device that measures the weight per unit length of powder and granules and calculates the instantaneous flow rate.

Since it is not a batch type, there is no possibility of intermittent flow of powder or granular material, and the equipment is large-scale, which is the same as in the case of hopper scales.

Furthermore, the annular balance type flow meter has a fulcrum at both ends of a diameter 1-diameter loop conveyor having a horizontally rotating disk, an inlet on one side, and an outlet on the other. It is a continuous flow meter. The powder and granules flowing in from 1 (1) are carried around half the circumference by the rotation of the disk, are dropped and discharged at the discharge port, and are carried along half the circumference of the disk by a load cell installed in a direction perpendicular to the diameter passing through the fulcrum. A signal proportional to the it of the powder or granule is transmitted, and this it
The signal is multiplied by an electric signal corresponding to the rotational speed generated by a rotational oscillator attached to the rotating shaft of the disk, and an instantaneous research signal is transmitted.

However, this annular balance type flow meter is no different from the previous two in that it is a large-scale device.

On the other hand, a drop impact flow meter, which is one of the indirect measurement methods,
Passing through the rectifier δ from a certain height 1) The instantaneous flow rate is calculated from the component force of the impact force applied by the powder fluid or the inclined plate, but it is expensive and takes a lot of time. In addition, there are problems such as the types of powder and granules are limited, the falling distance of the powder and therefore the mounting device of the inclined plate are limited, and the flow stitch display changes depending on the powder and granules, so it may be necessary to make corrections. be.

Another type of rotary torque flowmeter is that when powder is supplied from above to a rotating inner plate with a guide Since a proportional reaction force is applied to the rotating inner plate, the instantaneous flow rate can be determined from the moment created around the center of the rotating inner plate. This flowmeter is no different from the above-mentioned flowmeter in that it requires a large device.

By the way, transportation of powder and granular materials often uses gravity fall, and 1. Is it desirable to measure the flow rate by incorporating a flow meter at a desired position in a long pipeline in as small a space as possible? It is extremely difficult to install it at a desired position in the middle or to install it in many positions, so flow control in the powder processing process or process control based on flow rate does not work as expected or is it possible to perform detailed control? This is the reality.

([1st object and structure of the invention] The present invention has been made in view of the above points, and provides a flow measuring device that can be installed in the middle of a transportation pipe in a small space without stopping the flow of powder or granular material. In order to achieve this objective, multiple metering tubes are mechanically separated from the transportation tube and the metering tube directly downstream of the granular material in the transportation tube becoming a constant flow. The IT of the powder and granular material flowing inside each measuring tube is detected, and the flow velocity of the powder and granular material is determined by paying attention to the shape of weight change or the part where the weight is the same, and it is calculated from the weight per unit length of the measuring tube. It was configured to calculate the flow rate.

(Example) The present invention will be explained below based on the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of a flow stitch measuring device for powder or granular material according to the present invention.

Measuring tubes 2 and 3 of the same diameter are transported in series in the middle of an inclined transport pipe l that transports powder and granular material in the direction of the arrow. The metering tubes are mechanically separated from each other and are also mechanically separated from each other, and covered with a flexible cover 4 to prevent powder from leaking out from between the tubes.

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

7 and 8 are A/D converters that amplify the weight signals output from the load cells 5 and 6 by amplifiers 10 and 11, respectively, and then convert them into digital signals;
Next, use the cross-correlation function described later to find the delay time of the two weight signals, calculate the flow velocity of the powder using the distance between the centers of the two measuring tubes 2 and 3 along the flow path, and The flow rate is determined by calculating the weight per unit length and the flow rate thus calculated.

Next, a procedure for measuring a flow rate using the f&meter needle device configured as described above and the operation of the device will be explained.

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. Since the granular material flowing through the measuring tube 2 always flows through the measuring tube 3, the waveforms of the two weight signals A and B are extremely similar, although there is a slight difference between the two signals.

Therefore, the arithmetic circuit 9 calculates the delay time from the waveforms of these two weight signals A and B, and since the distance between the centers of the measuring tubes 2 and 3 is known, a cross-correlation function is used to calculate the flow velocity of the powder. A method called ``is used.

Generally, the cross-correlation function R1 (at) between two signals x (t) and y (t) can be expressed by the following equation.

(Margin below) Rwv (τ) = %: 47-6x (t)y(t+
? ) dtTherefore, the two weight signals A shown in Fig. 2
, B are sample-sung at every Δt, and A/D converted to produce W a + + l, W 1 . It is stored in the memory as t ; .

Here, if we calculate the cross-correlation function Rih+ between m consecutive data for each of the data strings of W a + i l and W b (i), we get the following. Here, k is 0.l, 2 When changing the value to .tau., .tau.; .DELTA.t-, the delay time can be found as .tau.; .DELTA.t-.

If the distance between the centers of the measuring tubes 2 and 3 is L, then the average flow velocity 7 of the powder or granular material is determined by L/τ. On the other hand, weight signals A and B
Calculate the average weight T from , or get the weight rw from either weight signal A or B, then calculate the flow rate G as G = W - x γ / (Test is from measuring tubes 2 and 3. average pipe length).

In this way, the flow rate of the powder or granular material can be determined.

In the example described in F, two measuring tubes were used, or two measuring tubes were used in the case of unreleased measuring tubes.
-1- You can use as many as you want as long as they are plural.

(Effects of the Invention) As explained above, in the present invention, a plurality of metering tubes are connected in series on the downstream side where the powder or granular material in the transportation tube becomes a constant flow. Separately provided,
Detect the weight of the powder and granular material flowing inside each measuring tube, and determine the flow velocity of the powder by focusing on the part where the shape of the weight change is the same, and calculate it from the separately determined weight per unit length of the measuring tube. Since the structure is configured to calculate the flow rate, the meter fJi can be incorporated into a part of the transport pipe in a small space, and the flow rate can be measured without stopping the flow of the powder or granular material. Therefore, the impact on the powder processing process and disturbances are small.

In the present invention, the flow rate can be determined regardless of the type of powder or granular material.

In addition, since no impact force is applied to the measuring section, static sudden calibration simplifies the calibration work of the current meter, and eliminates measurement errors caused by fluctuations in impact force.
stomach.

Further, the flow rate and integrated value of the powder or granular material can also be continuously measured.

[Brief explanation of the drawing]

FIG. 1 is a transport route diagram of an embodiment of the tuber measuring device for powdered or granular material according to the present invention, and FIG. 2 is a graph showing a weight signal in the enema measuring device for powdered or granular material according to the present invention.

Claims (1)

[Claims] A part of the powder transport pipe is cut, and at least two metering pipes are placed on the downstream side of the pipe in series with the transport pipe and mechanically separated from the transport pipe so as to prevent leakage of the powder. ,
A weight detection means for detecting the weight of the powder or granular material flowing in each of the measuring tubes and a flow velocity of the powder or granular material are determined by focusing on a portion where the shape of the change in weight detected for the at least two measuring tubes is the same. , a calculation means for calculating the flow rate of the powder or granule by multiplying the flow velocity by the weight of the powder or granule per unit length of the measuring tube.