SU1222567A1 - Method of automatic control for process of gypsum tempering in rotary gypsum mixer - Google Patents

Description

The invention relates to the building materials industry and can be applied to technological lines for the production of gypsum plasterboards.

The purpose of the invention is to improve the accuracy of regulation.

The drawing shows a device for implementing the proposed method.

In the rotary mixer with 1 screw 2 serves the plaster and through the pipeline 3 water-starch solution. Using the sensor 4, the current of the gypsum stirrer motor is measured, which is spent on mixing the gypsum with water. The sensor 5 measures the flow width of the gypsum mass at the exit of the gypsum mixer 1. In particular, it can be a matrix of sensor sensors based on the principle of capacitance variation with the passage of mass. The sensor 5 is installed under the lower moving cardboard, on which the mass of the gypsum mixer continuously flows.

In computing unit 6, the quotient is calculated by dividing the magnitude of the sensor 5 signal by the magnitude of the sensor 4 signal. an aqueous starch solution associated with the regulator 10 for supplying an aqueous starch solution.

Justification of the applicable law of regulation.

Structural systems, also called normal or Newtonian, are subject to Newton's law. Unstructured systems include dilute dispersed systems (suspension performance Q and itss). These include gypsum solution.

According to Newton's equation, the internal friction force F between parallel moving fluid layers is directly proportional to the area S of the contacting layers and the velocity gradient.

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In KjQ tp -, (5)

where Kj is the coefficient of proportionality.

Substituting in the equation (4) instead of Q its expression from the equation (5), we get

(one)

  i dx

 - system viscosity coefficient.

Gypsum mixer can be represented as a system of two vertical coaxial10

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cylinders, between the points are hyggs suspension. The outer cylinder is a gypsum mixer body, and the inner cylinder is blades with fingers rotating at a constant speed with. They bring the fluid (suspension) into a stationary rotational motion.

For this system, the moment M spent on rotation is equal to

MK gSw, (2)

where K is the constant of this device. Since under actual conditions the quantity Q of the suspension in the gypsum mixer is 15 l the contact areas S are changed, then the refined equation (2) will be as follows:

M K g Q,, (3) i.e. torque (power) on the shaft of the electric motor of the gypsum mixer drive is directly proportional to its performance Q and the viscosity of the mass. Asynchronous electric motors are used as the drive, the rotation speed W of which is almost constant. In a gypsum mixer operating mode, the power consumed by it fluctuates in the range that allows using the current in the motor winding as a parameter of the load cell. This simplifies the control device, since current sensors are structurally simpler and more widely distributed.

Based on the foregoing, the current I consumed by the motor of the gypsum propulsion drive is equal to

I J..l.Q ()

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The width B of the mass flow of the gypsum dough (suspension) on the bottom board after the mixer is directly proportional to

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In KjQ tp -, (5)

where Kj is the coefficient of proportionality.

Substituting in the equation (4) instead of Q its expression from the equation (5), we get

with

(6)

Kg .. In Kz T

By applying linearization (since the range of change in the operating mode of the gypsum mixer varies within its tolerable limits), we have

. -f example On a working gypsum mixer, the current of the gypsum mixer drive motor, the width of the gypsum cement flow stream at the outlet of the gypsum mixer, and the fluidity of the mass under various operating modes are measured. By measuring the output

number ratio --Results

experiments are shown in the table.

The proposed control method provides greater stability of the density of the gypsum dough at the outlet of the gypsum mixer. This helps to increase the uniformity of filling, the cardboard form of gypsum sheets, their strength, porosity,

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dignity, i.e. improve product quality. At the same time, the inoppet ratio decreases, which allows an increase in the productivity of the dryer and the output of products.

Claims (1)

METHOD FOR AUTOMATIC CONTROL OF THE GYPSUM MIXING PROCESS IN A ROTARY GYPSOMALATOR, including changes in the supply of gypsum and an aqueous' starch solution, measurement of the current of the gypsum mixer drive motor, oh t-. characterized in that, in order to increase the accuracy of regulation, the gypsum test flow width is measured, the gypsum test density is calculated by dividing the gypsum test width by the current of the gypsum mixer motor, and the change in the supply of the starch aqueous solution is carried out depending on the difference in the calculated gypsum test density from the set value.