RU2583130C1 - Device for automatic dispensing of flotation reagents - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: invention relates to devices for automatic dispensing of flotation reagents and other liquid components into technological process and can be used in dressing of minerals, as well as in mining, construction and other industries. Proposed device for automatic dispensing of flotation reagents involves dosing unit, control unit, pipelines, control and shutoff valves, at that, additionally contains measuring cup with bottom outlet pipeline with shutoff valve, and upper level sensor, wherein dispenser is secured at fixed installed tensoresistor, output of control valve via feed pipeline and flexible insert is connected with feed inlet into dosing unit, lower part of dosing unit has outlet branch pipe with built-in throttle. At that, control unit inputs are connected to signal outputs of tensoresistor and top level transducer, and outputs are connected to control inputs of control and shutoff valves.

EFFECT: technical result consists in improvement of reliability and accuracy of fluid flow control by eliminating effect of change of its physical properties by monitoring of actual consumption, as well as due to possibility of automatic calibration of dosing unit.

5 cl, 3 dwg

Description

The invention relates to devices for the automatic dosing of flotation reagents and other liquid components in the process and can be used in the field of mineral processing, as well as in mining, construction and other industries.

Known flotation reagent dispenser (Product catalog of Twell LLC. Flotation reagent dispensers series 8200-01. Electronic resource: http: // http: //www.twellgroup.ru/dosage_reagents.html), containing a magnetic induction flow meter, segment valve with pneumatic actuated valves for flushing and calibration. Dosing of reagents with this device is carried out by changing the degree of opening of the segment valve, depending on the required flow rate measured by the flow meter.

The disadvantages of the known device are the inability to measure the flow rate of liquids having a conductivity value and a speed below the threshold for devices operating on the magnetic induction principle.

The closest in technical essence and the achieved result to the proposed device is a device for automatic dosing of flotation reagents, including a dispenser, control unit, pipelines, control and shut-off valves (RU, utility model patent No.: 44178, class G01N 1/00, 2004 ) Dispenser housing is filled with liquid. The device also includes a displacer liquid level sensor and a capillary through which the fluid flows into the process.

The flow control in this device is carried out by regulating the liquid level in the dispenser housing, the value of which is functionally related to the flow rate and, therefore, the flow rate of the fluid flowing through the capillary.

The disadvantages of the known device for automatic dosing of flotation reagents are low reliability and accuracy of flow control, the lack of control of the actual flow rate of the flowing liquid.

Low reliability and dosing accuracy are due to the design of the level sensor, as the buoy's elevation is affected by the concentration (density) of the controlled fluid, as well as by the possibility of buildup of insoluble deposits on its surface in contact with certain types of fluids prone to sticking, leading to a change in its lifting force.

In addition, the velocity of the outflow from the capillary, in addition to the height of the liquid column above it, is affected by its viscosity, the value of which depends on the density, temperature and other time-varying factors.

The technical result, the achievement of which the present invention is directed, is to increase the reliability and accuracy of regulating the flow rate of the liquid by eliminating the influence of changes in its physical properties by controlling the actual flow rate, and also due to the automatic calibration of the dispenser.

The specified technical result is achieved in that the device for automatic dispensing of flotation reagents, including a dispenser, a control unit, pipelines, a control and a shut-off valve, according to the invention further comprises a measuring tank having an outlet pipe with a shut-off valve in the lower part and a top level sensor in the upper part, while the dispenser is mounted on a fixed mounted strain gauge, the output of the control valve through the supply pipe and a flexible insert is connected to the supply input of the dispenser, bottom Thread portion of the dispenser has an outlet with integrated choke, wherein the control unit inputs are connected to the signal outputs of the strain gauge and the upper level sensor and vyhody- to the control inputs of the control and shutoff valves.

In addition, the specified technical result is achieved in that the throttle can be made in the form of a washer with an adjustable bore, and also in that the level sensor can be made in the form of a proximity sensor.

The proximity sensor can be optical or capacitive type.

In FIG. 1 shows a device for automatic dosing of flotation reagents.

In FIG. 2 is a graph explaining the nature of the change in the output signal X1 of the strain gauge with a change in the height H of the liquid column in the dispenser housing.

In FIG. Figure 3 shows graphs of the dependences of the performance Q of the device on the height H of the liquid column in the dispenser housing.

The device for automatic metering of flotation reagents contains a control unit 1, a control valve 2, a shut-off valve 3, a supply pipe 4, a flexible insert 5, a supply inlet 6, a dispenser 7, an outlet pipe 8, an adjustable throttle 9, a measuring tank 10, an outlet pipe 11, which is fixedly installed a strain gauge 12, on which the dispenser 7 is fixed, the upper level sensor 13.

The operation of the device is as follows. From the outputs of the control unit 1 serves on the control inputs of the control valve 2 and the shut-off valve 3, respectively, Y1 and Y2 to open them. The reagent through the open control valve 2, the supply pipe 4, the flexible insert 5 and the supply inlet 6 enters the dispenser 7. Then, in the dispenser 7, the flow is divided into two parts. One part through the exhaust pipe 8, an adjustable throttle 9, a measuring tank 10, a shut-off valve 3 and an exhaust pipe 11 is sent to the process. The other part fills the internal volume of the dispenser 7. In accordance with the concept of the dispenser, the area Sd of the passage section of the throttle 9 is selected significantly less than the area Sk of the passage section of the control valve 2 in the open position. As a result, the liquid level H in the dispenser 7 will rise. At the same time, from the output of the strain gauge 12 to the input of the control unit 1, the signal X1 is proportional to the total weight of the dispenser 7 with the parts adjacent to it - the supply inlet 6, the outlet pipe 8 with the throttle 9, and the liquid filling it (thanks to the flexible insert 5, the weight of the supply pipe 4 and the control valve 2 is not cumulative with the weight of the dispenser 7 with parts adjacent to it). Since the weight of the dispenser 7 with the adjacent parts is constant, the variable part of the signal X1 is associated only with a change in the height H corresponding to the liquid level in the dispenser 7.

In FIG. Figure 2 presents graphs explaining the nature of the change in the output signal X1 for the described situation. In the initial position, in the absence of liquid (H = 0), the output signal X1 is constant and proportional to the weight of the dispenser 7 with parts adjacent to it (X1 = a0). As the dispenser 7 is filled with liquid and the height H increases, the output signal X1 begins to grow in accordance with the functional dependence

where a0, b are the coefficients of the equation describing the dependence of the output signal of the strain gauge 12 on the magnitude of the pressure exerted on it by a liquid column of height H and the concentration of the dosed substance C.

Further, with an increase in the liquid level H to a certain predetermined value Hb and reaching, according to dependence (1), a signal X1 of the value X1bad, unit 1 generates a control signal Y1 that provides a change in the degree of opening and, accordingly, the size of the area Sk of the passage section of the control valve 2 in this way in order to stabilize the output signal X1 of the strain gauge 12 at the level of X1ad, thereby maintaining the level of H in the dispenser 7 at a value of Had. Due to the fact that there is a known relationship between the column height H and the flow rate Q of the liquid flowing out of the vessel through an opening of area S (Lecture 5. Flow of fluid from openings, nozzles, and from gates. Electronic resource: http: // gidravl .narod.ru / istechenie.html):

where µ is the flow coefficient, depending on the conditions of flow and viscosity of the liquid;

q is the acceleration constant of gravity,

then maintaining the necessary height N back of the liquid column, provided that the value of the flow coefficient (µ = const) is constant, the dispenser ensures the supply of a given amount of reagent to the process.

Since the physical properties of different liquids are not the same and can change under the influence of external factors, for example, ambient temperature, before starting the dispenser, it is necessary to determine the coefficients of the functional dependence equation (1) and calibrate its flow characteristics in accordance with equation (2) .

The construction of the functional dependence (1) is carried out by fixing the values of the output signal X1 of the strain gauge 12 during gradual filling with a reagent with a known value C of the concentration of the dispenser 7 and the absence of fluid flowing through the outlet pipe 8 (the area Sd of the passage section of the inductor 9 is set equal to 0). By changing the concentration value (C1, C2 ... Cn), a family of functional dependencies can be obtained (Fig. 2). The coefficients of the equations of functional dependencies are recorded in the memory of the control unit 1.

The procedure for calibrating the flow characteristics is as follows. Set the value Sd1 of the flow area of the throttle 9 based on ensuring the passage of the required flow rate of the selected reagent. Specify some values of the height of the liquid H levels in the dispenser 7 - H1, H2 ... Hn (H1 <H2 ... <Hn).

The dispenser is turned on and a reagent with a known viscosity value (μ = const) is fed to its input. After stabilization of the liquid level H at the value H1, the control unit 1 instructs Y2 to close the shut-off valve 3, as a result of which the liquid level h in the measuring tank 10 will begin to increase. When the level h of the operation zone h reaches the sensor 13 of the upper level from its output, the input of block 1 receives the corresponding signal X2. The control unit 1 fixes the time T1 from the moment of applying the signal Y2 to close the shut-off valve 3 until the signal X2 is received. According to the received data, the control unit 1 calculates the coordinates of the first calibration point (H1; Q1),

where Q1 = V1 / T1 is the fluid flow rate (unit volume / unit time),

V1 is the volume of liquid in the measuring tank 10, made in the form of a cylinder with an area Smk of the base and the filling height h back;

T1 is the filling time of the measuring tank 10.

Similar procedures are performed to calculate the coordinates of other calibration points (Н2; Q2), (Н3; Q3), etc. (Fig. 3). For the obtained calibration points, one of the methods known in mathematics selects an approximating function, which is taken as the flow characteristic for given conditions:

where a1 is the approximation coefficient.

When changing the size of the area (Sd1, Sd2 ... Sdn) of the orifice of the inductor 9, a family of flow characteristics can be built. The obtained approximation coefficients are also stored in the memory of block 1.

In the case of a change in the viscosity μ of the supplied reagent, the calibration of the device must be performed again.

The calibration procedure can also be used to control the actual fluid flow.

Thus, the use in the technological processes of the proposed device for automatic dosing of flotation reagents can improve the reliability and accuracy of dosing of reagents by eliminating the influence of changes in their physical properties by controlling the actual flow rate, and also due to the possibility of automatic calibration of the dispenser.

Claims (5)

1. A device for automatic dosing of flotation reagents, including a dispenser, a control unit, pipelines, a control and a shut-off valve, characterized in that it further comprises a measuring tank having a discharge pipe with a shut-off valve in the lower part and an upper level sensor in the upper part, the dispenser is mounted on a fixed mounted strain gauge, the output of the control valve through the supply pipe and flexible insert is connected to the supply inlet to the dispenser, the lower part of the dispenser has an outlet pipe with built-in throttle, while the inputs of the control unit are connected to the signal outputs of the strain gauge and the upper level sensor, and the outputs are connected to the control inputs of the control and shut-off valves. 2. The device for automatic dosing of flotation reagents according to claim 1, characterized in that the throttle is made in the form of a washer with an adjustable bore. 3. The device for automatic dosing of flotation reagents according to claim 1, characterized in that the upper level sensor is made in the form of a contactless sensor. 4. The device for automatic dosing of flotation reagents according to claim 1, characterized in that the upper level sensor is made in the form of a non-contact optical type sensor. 5. The device for automatic dosing of flotation reagents according to claim 1, characterized in that the upper level sensor is made in the form of a non-contact capacitive type sensor.

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