JPS6091214A - Method for measuring flow rate of solid in descending stream by gravity - Google Patents

Abstract

PURPOSE:To compute the flow rate of solid, by providing two acoustic detectors in the direction of the axis of a vertical pipe at a specified interval, and obtaining the flow speed of the solid from the mutual correlation of the signal outputs of both detectors. CONSTITUTION:A solid flow-rate measuring apparatus is composed of a pressurizing tank 1 having a fluid bed, a pressurizing gas source 3, a distribution discharge pipe 4, a transport valve 5, a vertical descending pipe 6, a horizontal pipe 8, a nozzle 9, a carrier-gas blowing device 11, and the like. Then, two acoustic detectors 13a and 13b are provided on the vertical descending pipe 6 with a specified interval L being provided. Sampling devices 15, an operating circuit 14 having a correlator 16, and a solid flow-speed regulator 17 are provided. The detected signals from both detectors 13a and 13b are processed in the sampling devices and the operating circuit, and an average moving speed Vs is computed. the flow rate of the solid is computed by the solid flow-speed regulator 17, and the amount of discharge can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the total flow rate of a gravitational downward flow of powder or granular material in a pipe.

By installing two or more vibration or acoustic detectors in the axial direction of the vertical pipe and calculating the cross-correlation function of the signal output of the rain detectors, the influence of background noise from the outside can be removed and the influence of moving particles can be further reduced. This system is characterized in that the flow rate can be determined by removing all periodic fluctuations and calculating the average moving speed between two points.

Meuro is known from the acoustically detected signal of the mass flow rate of the downward gravity flow.

In other words, when solid particles (powder) flow through a transport pipe, collision and friction sounds are generated (before the particles), and these generated sounds (noise) are based on the number of particle collisions (proportional to flow velocity and concentration). What is the statistical average of this? It is known to determine the flow rate and flow rate. However, this generated noise has various wave numbers, for example 1. It is also possible to remove the noise to a sufficient extent by making all the specific frequencies of kHz to 8 kHz to be observed.

This method naturally places an octave fill and determines the cross-correlation function of the detected signal.

The invention will be described with reference to FIG. It is assumed that the granular material is flowing through the vertical downcomer pipe (6) at a concentration similar to that of the moving layer.

The detectors (13a-) and (13b) have the same characteristics, and one of them is variably provided at a distance corresponding to τ. These detectors can be installed both inside the pipe and on the outside wall of the pipe.

The detection signal from each detector is processed as a time function by the arithmetic circuit αa.
The statistical average moving speed τS is finally obtained after the arithmetic processing shown in the figure is input.

That is, the detection signals from the detectors (13a) and (13b) are sent to the sampling device Q to extract the entire time series of instantaneous values within a predetermined time (
Read as U+('
)+U2(t) total gain, which is taken as the input signal of the correlator θ0.

The cross-correlation function φ12(τ) for the time difference τ is
When 2=O, Ul(t) and U, (t+r)Q) Peak force dτ It is known that they match, so from τ at that time, υ5−
υ is considered as 7.

The flow rate is a function of the flow rate and from this flow rate the solids flow rate in the pipe is known.

FIG. 2 is a schematic diagram of the apparatus according to the embodiment of the present invention, in which the nozzles (9) to (4) can be cut out by changing the measured value of the solid flow rate controller (lη) according to the output τ from the computing unit. The pipe, (5) is a transport valve, (7) is a bent part, (8) is a horizontal pipe, αQ is a high temperature and high pressure supply end, and αυ is a transport gas blowing device.

The Hiko detectors (13aH13b) may be a pair of detectors symmetrical about the tube axis.

Since the present invention can completely cancel out the background noise that becomes noise during measurement, it is theoretically unnecessary to shield the detector, but in order to improve the axis of correlation, it can be applied even when the signal frequency is low. The trick is to install it with acoustic shielding.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a main part of the present invention, and FIG. 2 is a schematic block diagram of an embodiment of an applied device. (13a) (13b) are the detectors, (F51 is the sampling device (161 is the correlator patent applicant) fkeko 衾qRING・SAI Co., Ltd. 1!!! Sai 2

Claims (1)

[Claims] Based on the solid flow velocity determined from the cross-correlation function of multiple vibration or acoustic detectors fixed at a predetermined distance in the pipe axis direction of the pipe in which the granular solid descends at a mass flow rate similar to that of the moving bed. A solid flow measurement method for gravity downward flow, which is characterized by calculating the solid flow f'.