SU1300330A1 - Method and apparatus for determining density of broken ore lumps - Google Patents

Abstract

The invention relates to the field of instrumentation technology and can be used to determine the specific weight of ores during the enrichment of heavy suspensions. The aim of the invention is to accelerate the determination and ensure its continuity. Chunks of ore are taken from the process stream. Consistently injected them with a gutter in a container with water. The lower end of the gutter is mounted horizontally. This ensures that the initial vertical deposition rate is zero. During the precipitation of the pieces in the area of their accelerated movement, the time during which they cover a given distance is measured. The specific gravity is determined by the formula for g, / / ga, where UD is the specific gravity of the test, y is the specific gravity of the liquid, g is the acceleration of free fall of the body in vacuum, and is the acceleration of the conditionally free fall of the body in the fluid in a given part of its movement . 2 sp.f-ly. 1 il. to (L o so

Description

The invention relates to instrumentation engineering and can be used to determine the target weight of ores during the enrichment of heavy suspensions.

The purpose of the invention is to accelerate the determination and ensure its continuity.

The drawing shows schematically the device with which the method is carried out.

The device consists of a sampling device 1, installed in the general stream of enriched ore material (or additionally and in a stream of light and heavy fractions), feeder 2 and located under the discharge end of the last tank 3 with drain 4 and outlet 5 holes. Inside the tank 3 is installed inclined chute 6 with a horizontal lower end, which is lowered into. water and is connected to a support bracket 7 mounted on the front side of the tank. According to the height of the tank; Lena pair photosensors - sources 8 and 9 of light and photo cells 10 and 11, while the first pair of source

8 light - photocell 10 is installed in the upper part of the container 3, and the second (light source 9 - photocell P) - in the lower part, at a distance of 20-30 cm one ot the other.

In addition, the device includes an electronic stopwatch 12 connected to photo cells 10 and II, and a computing device 13, sensors 14 and 15 of the liquid level in the tank 3, transducers 16 and 17 to the level sensors, a logic circuit 18 for controlling the water supply to the tank 3, connected to the automatic valve 19 of the water supply line and the sampling valve 1.. The proposed method using the device for its implementation is implemented as follows.

The container 3 is filled with water to a certain level controlled by the sensor 15. As soon as the latter detects a predetermined level, a signal is sent from the associated converter 17 to the control logic 18 to stop the water supply and turn off the automatic valve 19.

At the same time, a signal is received from control logic 18

0

five

sampler gate 1 opening. Part of the enrichment material stream is directed by sampler G to feeder 2, which ensures that pieces of ore are taken from the sampled sample to slope gutter 6 one at a time interval of 1 s. On average, each representative sample contains up to 100-140 pieces of ore. Along the inclined chute, 6 pieces of ore are scooped into tank 3 with liquid. In the horizontal section of the chute, the movement of the ore pieces slows down, while the damping of their speed is influenced by the counter-resistance of the liquid. Therefore, at the initial moment of movement to the bottom of the tank 3, the vertical speed of each piece of ore is zero. The time interval of 1 s eliminates the simultaneous gathering of several pieces of ore from the horizontal section of the inclined chute 6.

With further movement under the action of the force of gravity, the speed of movement increases, i.e. chunks of ore begin to accelerate in the water. However, with an increase in the speed of movement of the ore pieces, the resistance of the liquid also increases, and at some point in time the force of gravity and the force of resistance balance. From this point on, the movement of pieces of ore in the water becomes uniform, i.e. they 5 begin to move at a constant speed.

Acceleration acts on the initial, initial section of the path, where the resistance force is less than the force of gravity, and is determined by the time it takes for the ore chunks to pass through this section.

For large pieces of ore material, the resistance in the initial part of their path in the liquid can be neglected and can be considered as a free fall. The acceleration of free fall a in water differs from the acceleration of free fall in vacuum by an amount determined by the difference in the specific gravities of the body and water.

0

0

five

0

J: b. Have

g

(ABOUT

where y is body weight; Wo the specific gravity of water, whence we get the equation

f "-Jfo / S-a,

3

which makes it possible to calculate the body weight due to the acceleration of its relatively free fall in water in the initial part of its movement. We give the formula (2) to the form. g

Have

gt

- 2x

7

expressing acceleration through time pro

During the passage of each of the pieces of ore of the sample under study, an electronic stopwatch 12 is activated by the signal from the specified photocell, and at the time of passage of each ore between the bottom source of light 9 and With the lower photogeneral 11, the electronic stopwatch is turned off, alternately fixing the time of flight of the distances between the sources of light and the photocells (20-30 cm) by pieces of ore. The calculating device 13 calculates the approximate the specific weight of each piece of ore from the sample, calculates the average specific weight of the entire sample from the results of all measurements (100-140 measurements, according to which the average specific weight of the whole stream of enriched ore is measured.

The choice of the initial part of the movement of pieces of ore in a liquid (water) is determined by the requirements for measurement accuracy: an excessive resistance of the medium affects an excessively large area, in the case of a short initial area, very short periods of time must be measured, which is technically difficult.

Measurements have shown that for hour -.-particles of the class under study + 10-30 mm the most optimal for calculation is the section of the path 20-30 cm.

Sensor 14 is adjusted to a predetermined increase in the water level in the tank 3,; which occurs upon receipt of the studied ore samples into it. As soon as the level-FLUID in the tank 3 reaches the value controlled by the sensor 14, through the converter 16 connected to the sensor 15. a level, the logic 18 receives a signal to open the outlet 5 of the tank 3. After emptying the tank

the rhoda is refilled and the enrichment ore sampling process is resumed. For emergency discharges of water, it is provided to drain its surplus through hole 4.

fO

20

. . g 25 jq

Claims (2)

1. A method for determining the specific gravity of pieces of crushed ore, consisting in taking a sample from the process stream, sequentially immersing each piece of ore of the sample being studied, in a liquid and measuring the time of movement of a piece of ore in a liquid in a given part of the path, characterized in that accelerating the determination and ensuring its continuity, introducing each piece of ore into the liquid of the sample under investigation is carried out with an initial vertical sedimentation rate equal to zero, and choosing where the piece of ore moves rapidly, after which the specific gravity of the piece of ore is determined by the formula and  -B- g-a  . g 25 jq 40 45 0 where is the specific gravity of the test; . Od - specific gravity of the liquid; - acceleration of free fall bodies in a vacuum; a is the acceleration of a conditionally free fall of a body in a fluid at a given part of its movement. 2. A device for determining the specific gravity of pieces of crushed ore, containing a sampler, a water tank with a drain hole and two photosensors installed in pairs in a given area, which, in order to speed up the determination and ensure its continuity, between the sampler and a water tank is equipped with a feeder, the discharge end of which is located above the inclined chute located inside the tank with the horizontal lower end, while the photo sensors are installed under the chute in an accelerated area movement of pieces of ore. ..X  f 19 -.water Compiled by V. Alekseev Editor L. Veselovska Tehred I. Popovich Corrector L. Patay Order 1142/41 Circulation-777 VNIIPI USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 Subscription