SU1506287A1 - Method and apparatus for weighing stream of loose material - Google Patents

Abstract

This invention relates to weighing technology, in particular, to weighing bulk material in a stream using a cantilever type weighing conveyor. The aim of the invention is to ensure high weighing accuracy regardless of the uneven distribution of material on the conveyor belt during the movement. The total mass of the material is determined by integrating over time the instantaneous performance at the input of the conveyor in its local section. The proposed device is intended for use in the development of continuous dispensers and conveyor scales of increased accuracy for use in agriculture, animal feed production, powder metallurgy, chemical industry and other traditional households, where it is necessary to meter and weigh bulk material in continuously flowing technological processes. 2 sec. f-ly. 1 il.

Description

The invention relates to weighing technology, in particular to weighing bulk material in a stream using a weighing conveyor, a cantilever type, and can be used in the development of continuous metering devices and conveyor scales of increased accuracy.

The purpose of the invention is to improve the accuracy of measuring uneven material flow.

The drawing shows the structure of the p-scheme of the device for carrying out the method of weighing the flow of the flow material.

The device consists of a cantilever weighing conveyor 1 supported on a load sensor 2, a normalizing converter 3, differentiation units 4 and 5, an inverter 6, an adder 7, a unit 8 for recording the total mass of material, a differentiation unit 9, a switch 10I latency and pointer 12 instant performance.

The device provides weighing of the material in the stream with the help of a cantilever type conveyor in two loading modes

about

Od

to

00

3150

rial When loading the material from the fixed support side, the switch 10 of the material loading mode is in the normal position (Fig. 1).

The device works as follows.

The electrical signal from the force-measuring sensor 2, proportional to the force F (t) generated by the weight of the material passing through the conveyor 1, after being converted into a unified DC signal by means of the normalizing converter 3, is fed to the input of two series-connected differentiation units 4 and 5 .

At the output of differentiation unit 5, a signal is obtained, representing a second-order derivative

dfF (O dP

the first term is fed to the input of the adder 7, the inverter 6 by the mine (the inverter is shorted by the normally closed contacts of the first contact group of the switch 10). The second term Q (t -T), which is fed to the input of adder 7, is obtained by means of a feedback connection encompassing a delay unit 11 that delays the output signal Q (t) of adder 7 for a time T equal to the residence time of the material on the conveyor belt . Prefunctions of P (t), which, as

 dQ (t -t) term with

dt

served

To the input of the adder 7, from the output of the differentiation unit, to the input of which, through normally closed contacts of the second group of contacts of the switch 10, the signal Q (t -t) is delayed by the unit 11.

As a result, a signal is received at the output of the adder 7. . , g.

Q (t)

) dt.

+ Q (t -t) -t4. -jr-EQlLl dt

which is a function of changing the instantaneous performance at the entrance of the conveyor in its local section when loading material from the Fixed Support. When the material is loaded from the side of the force sensor, the switch 10 is moved to the opposite position. At the same time, the output of the totalizer 7 is connected to the output of the differentiation unit 9, and the inverter 6 is connected to its output. At the output of the latter, received -Kt)

is - with /

dt

- derivative of the second

F (t.) with minus sign, and at the output of differentiation unit 9, derivative of the first order of output signal Q (t) of adder 7, which through normally open contacts of switch 10 is fed to input of differentiation unit 9.

As a result, the output of the adder 7 receives a signal

Q (t) - 7 dQ (t) dt

+ Q (t -) +

0

five

five

five

0

g

0

which is a function of the instantaneous performance change at the input of the conveyor in its local cross section when loading material from the load sensor.

From the output of the adder 7, the instantaneous performance signal Q (t) is fed to the inputs of the yuazatel 12 instantaneous performance and the metering unit of the total mass of the material, where this signal is integrated over time, the voltage is converted into a frequency signal and the sum of successive pulses in the counter, the total mass of material (G) passed through the conveyor.

Claims (2)

1. A method of weighing the flow of bulk material, which consists in integrating in time the performance of a weighing conveyor mounted on a fixed support with a constant speed of movement — a tape — which determines the total mass of the material that passed through the conveyor, characterized in nor the accuracy of measuring the uneven material flow, additionally measure the rate of change of the force generated by the flow of materials transported from the conveyor side; fixed support, after which the instantaneous productivity at the entrance of the conveyor to the harness is determined local section of vf Q (t) - (-1) Cl dF (t) d (t) + Q (t –C) + L.1. dQ (t g) dt de F (t) Q (t) (t-e) and t g l with , f-o. to the rate of change of the force generated by the flow of material being transported; instantaneous performance at the entrance of the conveyor in a local section at times t and (t-G), respectively; dwell time of the material on the conveyor belt; current time; an even integer when loading material from the fixed support; an odd integer when loading material from side opposite the fixed support. 2. A device for weighing the flow of bulk material, comprising a conveyor, one end of which is mounted on a support and the other connected to a load cell, a normalizing transducer, an instant performance indicator and a total mass metering unit, characterized in that, in order to improve the measurement accuracy of uneven material flow, it introduced three a differentiation unit, an inverter, a delay unit, an adder and a load mode switch with two groups of contacts; the output of the load cell through the serially connected normalizing converter, the first and second differentiation units and the inverter, covered by the normally closed contacts of the first group, are connected to the first input an adder, the output of which is connected to the input of the total mass metering unit and the instant performance indicator, to a normally open contact of the second group and to the input from the delay unit, whose output is connected to the second input of the adder and through normally closed contacts of the second group to the third input of the adder.