SU1392452A1 - Device for determining concentration of suspensions - Google Patents

Abstract

The invention relates to a measurement technique and is intended to measure the concentration of aqueous suspensions, in particular, those prone to foaming, by the volume-weight method. The aim of the invention is to expand the functional capabilities of the device by determining the concentration of suspensions prone to foaming, improving accuracy by reducing the weight loss of the suspension, simplifying the measurement process. The measuring capacity 1 of a constant and a volume bounded by an overflow opening 2 is mounted on a balance 7 equipped with a mass sensor 8, a compensation weight divided into two parts 9 and 10, and a calibration weight 11. The ratio of the mass of the suspension and water entering the measuring capacity 1 is determined by The mass ratio of the parts of the compensation weights 9 and 10. The supply of the suspension is controlled by the valve 3 connected to the mass sensor 8 via the counter of parameter 18 and the automatic installation unit 17. The water is supplied through the valve 4, and the supply stops at the beginning of overflow through hole 2 is controlled to change the rate of change of the signal from the sensor 8 via the differentiator 13 and the analyzer. ra rate of mass change 12. i SL OO (; o to 4 SL to

Description

139

Management of weighing and filling processes is carried out using the control unit of weighing range 1D and circuit 15. The desired suspension concentration is calculated in a computing unit with a device

register 20 using the scaling unit 19, taking into account the temperature correction in the tabular data block 16 on the temperature of the suspension, measured by sensor 6. 2 Cp. f-ly, 1 ill.

one

The invention relates to a measurement technique, namely, an automatic weighing device for measuring the concentration of aqueous suspensions, as well as suspensions prone to pricing, in process lines.

The aim of the invention is to enhance the functionality of the device by determining the concentration of suspensions prone to foaming, improving the accuracy by reducing the weight loss of the suspension and simplifying the measurement process.

The drawing schematically shows a device for determining the concentration of suspensions.

The device contains a measuring container 1 with an overflow opening 2 providing constant volume, a suspension supply valve 3, a water supply valve 4, an exhaust valve 5 and a temperature sensor 6 mounted on a scale 7 equipped with a weight sensor 8, a compensation weight divided into parts 9 and 10 with masses Pd and P, p and calibration weight 11 with mass, analyzer 12, mass change speed, differentiator 13, weighting range control unit 14 -. NIN, AND circuit 15, tabular data block 16, automatic installation block 17, parameter counter 18, scaling block 19 and computing unit 20 with a recorder.

The device works as follows.

A compensation method is used. Before each cycle of determining the concentration, weights are calibrated, and the sequence of imposing weights is determined by the weighing range control unit 14.

Initially, the scales are loaded with parts 9 and 10 of the compensatory

weights (with masses РД and Р, „) for imitation of pouring of measuring capacity. The signal N, sensor 8, proportional to the total mass of these weights, enters the parameter counter simultaneously to the scaling units 19 and the automatic setting 17 at the resolution of the direct input of the AND circuit and to the computing unit 20 for storage.

The balance is then loaded with a calibration weight (mass P) defining the working part of the sensor characteristic, and the corresponding signal is fed to the scaling unit 19 to calculate the scale factor K using the formula

PII

- N,

 Soo

After this weight, besides weight 10, weights are removed and the suspension is fed into the container through the filling valve 3, which is closed by the command of the automatic installation unit 17 when the signals of the sensor 8 and the setpoint N are equal. in the tank after the valve 3 is closed, it is entered through the counter 18 of the parameter in the calculation block 20, where the mass of the suspension PC is calculated by the formula

RS

 PIO- N,) K - PJ2)

10 s 1 10

Next, the weight 10 is removed from the balance and the water is loaded into the container 1 according to the resolution of the inverted output of the circuit I, while the loading rate is controlled by the differentiator 13 and the analyzer 12 of the mass change rate. Since the moment of overflow by mass is unknown, the cut-off is made when the rate of mass increment in the measuring capacity drops to a predetermined value corresponding to the beginning of the overflow. In this way, a minimal loss of suspension from the tank is ensured and the accuracy of determining the concentration is improved.

The NJ sensor signal goes to block 20 to calculate the mass of the diluted suspension P using the formula

V RE - Ryu with - i) K, (3)

and to calculate the concentration of C using the formula

l fSulJP Ll-Pc) Рж1 IPcfft Jfre-P

where Pg,,

RC, p, - the mass of water in the volume

the measured capacitance, the density of a solid, the density of water and the density of a liquid as a function of temperature, the values of which are in block 16 of tabular data according to the working temperature range with a discrete value of 0.2 C.

The value of Pg is the mass of water in the volume of the measuring tank, as a function of temperature in the range of operating temperatures for this capacity, measured in advance, a table is compiled and the data P for each measurement according to the temperature of the suspension are automatically extracted from the tabular data block and used to calculate formula (4) as well as the values of, pg, P and the ratio of the parts of the compensation weight P J and P 1, from O to 1, when the sum of P + P, j is constant, the suspension mass can be changed from 0 to 100%.

The control unit 14 is a program control unit t for setting weights of compensation weights Pg and P, p, intended for controlling the weighing range and provides the following functions in the device:

calibrates the scales in the working weighing range in order to determine the scale factor by loading the scales with compensation weights of mass (P ,,) (sensor signal 8 has the value N,)

g

ten

15

20 25 20

dO d5

n 55

and the subsequent loading of the calibration weight P ,, (the sensor signal has the value No);

provides a measurement of the suspension mass poured into the measuring capacity in the range from 0.0 to 1.0 volume of the capacity in a calibrated working weighing range by applying a weight P weighing to the balance, the weight of the suspension being filled in is determined by the weight of the PW weight, the suspension cutoff is produced at the level of the sensor signal N, and the mass of the suspension corresponds to the value of the signal N, the value of which is always greater than N, and therefore is in the working measuring range.

The logic circuit 15 also interconnects the state of compensation weights Pg and with the mode of filling the tank 1 with liquids (valves 3 and 4), as well as the shape of synchronizer 1 for 1 and 1 in blocks 17 and 19.

The direct output And takes place when there are two signals at the input at the same time on the lifting of the weights Pj and, in this case, the number N is recorded in block 17 and 9. The inverse output occurs when both weights are omitted. The signal is then supplied to the inlet WATER (valve 4).

Logic element 4, connected, 1J with control unit 14, expands the functionality of the device, allows calibrating the balance, checking the entire system a1 by filling the tank with water (when Pa and P, d are removed), as well as loading the balance with the weight P o filling the tank with the required amount of suspension, and while lifting the weight P (about topping up the tank with water before overflow. In addition, when weights are loaded with the weight P, with a mass equal to zero, the tank is filled only with suspension, in case the suspension is not prone to niyu.

The computational unit 20 registers the following data on the printing form: N, N, K, M, P, t, c, then the contents of the container are drained and washed with water. Thus, the division of the compensation weight into two parts allows dilutions that are prone to foaming to be diluted with water in a wide range of proportions of their volume. Process

concentration measurements — weighing, valve control, filling volume measurement control, processing of measurement results — simplified by automating all operations.

Claims (3)

1. An apparatus for determining the concentration of suspensions, including a scale with a mass sensor, a compensation and calibration weights, a measuring tank with inlet and outlet valves, a parameter counter, a scaling unit and a recording unit, which is the fact that, in order to expand the functionality of the device by determining the concentration of suspensions prone to foaming, the compensating gear is made in the form of two parts with a range of changes in the relative weight of each part from m to n minutes setpoint, the output of which is coupled to the slurry supply valve and one part of the compensating weights, and input - with sensor mass through counter parameter. ten 20 j 392A526 2, The apparatus according to claim 1, characterized in that, in order to improve the concentration measurement accuracy by reducing the suspension weight loss, a differentiator and a mass change rate analyzer are introduced, the input of the mass rate analyzer input is connected through the differentiator to the output mass sensor, and the output is connected to a water supply valve. 3. A device according to Claim 1, characterized in that, in order to simplify the measurement process, a weighing range control unit and an AND circuit are introduced into it, the first output of the weighing range control unit is connected to the control input of the calibration weight, its second output is with a controllable input of the first part of the compensation mass, the first input of the AND circuit and a controllable suspension supply valve, its third output is connected to a controllable input of the second part of the compensation mass And the second input of the circuit is And, the direct output of which is connected to another input of the automatic setpoint unit, and its inverse output is connected to the controllable water supply valve. 25 thirty