SU1728029A2 - Device for control of the process of manufacturing concrete and reinforced articles - Google Patents

Abstract

The invention relates to the field of automation of technological processes for the production of concrete and reinforced concrete products, can be used in the building materials industry and allows for improved control quality. The device contains sensors 3 strength of products 2, sensor 4 temperature in the unit 1 heat treatment, switches 5 on

Description

the number of aggregates, central switch 6, block 7 for determining the minimum value of strength, driver 8, block 9 for determining properties of cement, autocorrelator tor-extrapolator 10, optimizer 11, block 12 for correcting cement consumption, block 13 for determining the duration of heat treatment, block 14 correction of heat treatment modes, regulators 15 by the number of aggregates 1, block 16 for setting the concrete setting time, block 17 for determining preliminary exposure, block 18 for determining deviations, block 19 for determining daily strength, block 20 Moisture of inert aggregates, unit 21 chemical additives and steam supply actuators for each unit, conductivity sensor 54 with converter 55, differentiator 56, comparator 57, gate water control unit 58 with regulator actuator 59 59. 1 ill.

The invention relates to the field of automation of technological processes for the production of concrete and reinforced concrete products, can be used in the building materials industry and is an improvement of the device according to ed. St. N ° 1416320.

The aim of the invention is to improve the quality of control.

The drawing shows a block diagram of the device.

The device contains heat treatment units 1, each of which includes products 2 with a corresponding strength sensor 3 and temperature sensor 4, and a control system that includes switches 5 by the number of units, central switch 6, unit 7 for determining the minimum strength value, driver 8, unit 9 determine the properties of cement; autocorrelator tor-extra pol tor 10, optimizer 11, cement consumption correction block 12; block 13 for determining the duration of heat treatment, block 14 for adjusting the modes of heat treatment, regulators 15, block 16 for determining the setting time of the concrete mix, block 17 for determining the preliminary exposure, block 18 for determining deviations, block 19 for determining the daily strength, block 20 for determining the humidity of inert aggregates; block 21 chemical additives; steam actuators 22 for each unit. The switches 5 and 6 include a relay matrix 23, a multivibrator 24, a counter 25, a decoder 26 and a key block 2.7; a block 7 for determining the minimum strength value includes an ultrasonic device 28, an analog-to-digital converter 29 and an arithmetic unit 30; driver 8 includes a digital-analog converter 31 and comparator 32; the autocorrelator torus-extrapolator 10 includes a subtractor 33, a quadrator 34, an adder 35, a subtractor 36, a circuit 37

square-root, two splitter 38 and amplifier 39; the cooking time determination unit 13 includes an input register 40, an arithmetic unit 41, a command counter 42 and an output register 43; block 14 for the correction of cooking modes includes two DACs 43, an OR circuit 44, an arithmetic unit 45, a memory 46, a counter 47, a memory 48 and a DAC 49; the preliminary exposure determining unit 17 includes two comparators 50 and the circuit OR 51; the deviation determination unit 18 includes two comparators 52 and an OR 53 circuit.

In addition, the device is additionally equipped with an electrical conductivity sensor 54 (made in a four-electrode scheme) of a concrete mix with a converter 55 (voltmeter), a differentiator 56, a comparator 57, the output of which is connected to the inputs of the chemical additives unit 21 and the block 58 (for example, a trigger) with an actuator 59 (relay) of the regulator 60 (magnetic valve) installed in the supply water pipeline for the second stage of the concrete mix preparation.

Additional blocks 54-60 serve

for the implementation of the two-stage technology of concrete mix preparation. The selection of the initial heat treatment mode and the correction of the cement consumption is carried out in blocks 1-53 of the prototype.

A device for controlling the manufacturing process of concrete and reinforced concrete products works as follows.

The kinetics of increasing the strength of concrete in product 2, which is in heat treatment unit 1, is monitored by strength sensors 3, which at certain intervals after the start of the cycle: heat treatment, by means of switches 4 and central switch 5 are connected in series to unit 7

determine the minimum strength value. In this case, the reference pulses from the multivibrator 24 are fed to the input of the counter 25. Each cell of the counter is connected to the coordinate buses of the matrix decoder 26. The outputs of the decoder 26 through the block 27 of transistor switches are connected to a relay matrix 23 made on magnetic relays, and are used to connect sensors actuators and actuators to the control unit and the control circuit, respectively

 Tretg

max-77 -, UJ

7 1zam

where y is the duty cycle of the relay matrix; Treg is the interval of adjustment of the regime parameter (temperature of steaming); Tzam - closing time of the regulator to the actuator.

The adjustment interval of the Regg excluding the zone, the ambiguity of the regulator is selected from the following limits:

go "-Trvg -To1p (1 -fa) -ro #)

where T0 is the delay in the transmission of control actions;

That is the time constant of the object;

IB is a disturbing (controlling) action.

The time of the closed state of the outputs of each relay of the matrix 23 is determined from the condition:

tsaM

(3)

Kim kim

where p & onfj are the tolerances of the mode parameter in steady state; Ko - transfer coefficient of the object to be regulated; Kim - indicator of the regulatory body, 14%.

In block 7 for determining the minimum value of strength, the strength of the product in the worst heat treatment conditions is established. This happens as follows. The signal from the switch 6 is fed to the input of the ultrasonic device 28, which captures the current strength value RJ of the test item I located in chamber j, and from the output of the device 28 through the analog-digital converter 29 the signal goes to the arithmetic unit 30, where the algorithm itself is implemented searching for a product with a minimum value of strength Pmin according to FIG. 1. At the same time, at the beginning of operation, the index (number) of camera j is set to a single value (the first camera is connected via switch 6 to block 7), the index of the item to be monitored i is set to one

(the first product of the first steaming chamber is connected through the switch 5 and the central switch 6 to block 7), the index of the current strength value RI takes

5, the strength value of the first RMHH product is RI. The whole algorithm for determining the minimum value of strength includes two cycles: I — determining the minimum value of strength in each of the m chambers: I — polling all m chambers of heat treatment. After establishing the minimum strength of the product, the digital signal from the arithmetic unit 30 of block 7 is fed to the input of digital analog converter 31. shaper 8.

After converting the digital signal, analog comparator 32 compares

20 set value RMHH with a signal given in the form of a voltage level at the control input of the comparator 32 corresponding to the output strength of the product Rom. From the first output of the imaging unit 8, a signal in the form of an electrical impulse arrives at the input of the block 9 for determining the properties of cement. Before the work shift, for operation of the device, ultrasonic devices of the unit 9 are inserted into beams of 40 x 40 x 160 mm to determine the activity of the cement used. Solutions for the beams are prepared at a water-cement ratio of 0.4, and their consistency in the spraying of the cone after 30 shakes on the table should have a diameter in the range of 106-115 mm. The beams from the solution are stored in forms above water for 24+ 2 h, placing in a bath with a hydraulic shutter.

40 Next, they are molded and stored in water (temperature 20 ° C ± 2 ° C) for 27 days. After 28 days from the moment of manufacture, the beams are placed in the electrodes of the ultrasonic device of unit 9. The strength limit indicator in this case is the cement activity.

From block 9, an electric signal proportional to the value of the activity of the cement used to make this batch of products, at the command of block 8, is fed to the input of the autocorrector of the extrapolator torus 10, where the prediction is to determine the activity

55 cement at the time of preparation of the concrete mix in subsequent batches by determining the coefficient of activity variation from the results of tests of cement, current and produced for the quarter, according to the formula:

V

j2 (A-Acp) 2 / (n-1).

LR

100, (4)

where V is the coefficient of variation,%; AJ - cement activity of a separate (i-th) lot, kgf / cm2; АСр - average cement activity of this brand per quarter, kgf / cm; n - the number of lots of cement of this brand, produced for the quarter. The subtractor 33 of block 10 determines the difference between the cement activity values of a single (i-th) batch and the average cement activity of a given brand over a quarter; quadrant 34 squares the resulting difference, after which the signal goes to adder 35. Subtractor 36 subtracts the unit from the number of lots of cement of this brand, produced in a quarter. The partial result of the calculation of the blocks 35 and 36, obtained in the divider 38, in the form of an electrical signal is fed to the square root extraction circuit 7. The resulting signal from the output of the autocorrelator — the extrapolator 10 is fed to the input of the automatic optimizer 11, which implements the algorithms for finding the minimum of the technical and economic criterion, which is a variable part of the cost, equal to the sum of the costs of cement and heat treatment the quality of concrete products. Depending on the specified restrictions imposed on the specific consumption of cement and the duration of heat treatment, organizational and technical restrictions, including work shift, product range, availability of material and energy resources and the state of related technological posts, the optimizer 11 decides whether the specific the consumption of cement in the concrete mix of subsequent curtains, as well as the duration of isothermal heating for the next product or batches of products.

The cost of maintaining the equipment is determined by the formula

Sob (3.22 Aob + 1.6 2 AF) / R, (5)

where Cv is the sum of expenses for maintenance and operation of all types of equipment of this line, A0b is the amount of depreciation deductions determined for all units and machines of the line according to the norms, AF - the same for forms, forms-trolleys, accessories; P - year line capacity.

The actual specific calculation of energy resources at the plant, taking into account the energy costs in the auxiliary workshops (preparation

concrete mixture, storage of materials in warehouses, production of fittings, intrashop and in-plant transport) and in the service units (repair services, heating, hot water, lighting, ventilation, etc.) are calculated by empirical formula

on OS | /

Ez 1,566 B1 (25 + EtKzK4) №)

where Et is the energy consumption for heat and moisture treatment of products, taking into account the heat loss in the structures of chambers, the steam system and due to the imperfection of the organization of production; n is the number of production lines in the enterprise, Ki is the coefficient taking into account the workability of the concrete mixture used and the method of its compaction taken according to factory data; Ka is the coefficient taking into account the type of the production line on which the products are produced, taken to be equal for conveyor lines, in-line - aggregate 1.04, cluster 1.1 and bench 1.13, Kz coefficient taking into account the type of thermal unit used; “4 - coefficient taking into account the type of cement used.

After the automatic optimizer 11 makes a decision to change the specific cement consumption in the concrete mix of the subsequent batches, as well as the duration of isothermal heating for the following products, the signal proportional to the values of the need for changes from the output of the optimizer 11 is fed to the dosing control system which provides preparation of concrete mix in the subsequent batch of the changed structure. In the commercially available SUBZ-1 concrete plant control station, contactless track sensors are used to determine when the feeder is turned off. A proximity sensor is mounted on an additional arrow, which indicates the target mass of the dose of cement. As the material enters the metering hopper, the main arrow rotates around its axis. When the current dose coincides with a predetermined signal, it enters the control unit, which turns off the feeder. On commercially available dial heads, several additional hands are usually installed with proximity sensors located on them. These sensors are used in this device to control the dosing on command from unit 11.

From the second output of the imaging unit 8, the resulting signal is fed to the input

Block 13 for determining the duration of heat treatment, where the time of isothermal heating of products is determined by the formula:

- L- J

R (t) Cie T1 + C2e T1, (7)

where R (t) is the tempering value of the strength of the product at the moment of time t,%, Ci is a coefficient that is numerically equal to the strength of the product at the moment of its loading into the chamber; C2 coefficient numerically equal to the strength of the product at the time of the heat supply to the chamber; Ti, Ta are time constants that determine the rate of strength change over time during natural hardening and when heat is supplied to the chamber, respectively; s; t is the heat treatment time.

Block 13 works as follows.

Before the heat treatment cycle, the duration of the heat treatment mode set at this plant is recorded in the input register 40. On a signal from block 8, the command counter 42 issues a command to the input register 40 and the arithmetic unit 41 about the adjustment of the heat treatment mode. The arithmetic unit 41 produces an increase or decrease in the established mode of heat treatment of products. The final duration of the heat treatment cycle is recorded in the output register 43 of the block 13. The output of the block 13 is connected to the input of the heat treatment correction block 14, in which the new value of the isothermal heating time for the heat treated products is stored. In the absence of signals from blocks 17, 18, 21, block 14 performs the TVO cycle set by block 13, otherwise (if there is a signal from one of the listed blocks) the TVO modes are corrected. The signals from blocks 17 and 21 through block 43 and the OR circuit 44 are fed to the arithmetic unit 45 and to the command counter 47 of the block 14. From the output register 43 of the block 13, the established TVO cycle goes to the memory 48 of the block 14 and is inputted from the command counter 47 for adjustment to the arithmetic unit 45. The corrected isothermal exposure time of products from the arithmetic unit 45 is recorded in the operational memory 46, the number of which is equal to the number of thermal chambers. Digital signals from the operational storage devices are fed to digital-to-analog converters 49, from the output of which in the form of analog signals are fed to the second input of the controller 15.

At the first input of the controller 15 mode

heat treatment from the output of the temperature sensor 4 receives an electrical signal proportional to the temperature in the thermal unit 1. From the output of the heat treatment mode controller 15, the resulting electrical signal enters the input of the actuator 22 installed on the heat carrier supply line to the thermal unit 1.

Block 18 gives a signal to the first input.

17 determining the pre-exposure for adjusting the pre-exposure time depending on the setting time of the concrete mix. The principle of operation of block 16 is based on the fact that such parameters of heat treatment as pre-exposure time and the start of isothermal heating are associated with the setting time of the concrete mix. If the deviations exceed the allowable

the value controlled by block 16 is signaled and a corresponding correction is made by block 17 when the start of setting does not match and blocks 10 and 14 when the end of setting of the concrete mix does not match. If the setting time is within the calculated, then the adjustment mode is not made. Comparators 50 through the scheme OR 51 blocks

17, a control signal is output to the TVO mode correction unit 14.

Block 19 determines the actual strength of products at the age of 28 days. The value of this strength is analyzed by the unit.

18 determine the deviations by comparison with the design. In this case, the signal from block 19 is compared by the comparator 52 with a signal level corresponding to the design value of strength. If the deviation is out

beyond the set limits (for example, 10%), the signal from the comparator 52 as a controller is fed through the circuit OR 53 to block 17, the signal from which the pre-exposure changes, and is changed within the set concrete setting time block 16 (for example, 0.1, 0.2 ... tskhv). The unit 20 for determining the moisture of inert aggregates determines the moisture of inert

aggregates (sand and rubble) and in proportion to its value gives a signal to the block

18 determine the deviation of the adjustment of the time of preliminary exposure of concrete products.

Immediately before the heat treatment cycle, a voltage level corresponding to the type of chemical additive used (moderator or accelerator) is established on the block 2 chemical additives. If a concrete hardening inhibitor is used, the output level of block 21 is -5V; if a concrete hardening accelerator is used, the output level of block 21 + 5V. If chemical additives are not used in the manufacture of products, then the output signal level is 0. At the same time, in essence, the command from block 21 does not adjust the TVO mode. In particular, this explains the fact that block 21 is a voltage block,

The amplifier 39 of the unit 10 is an amplifier with a gain of 100, it performs the multiplication of the result with the division 38 by 100, i.e. calculation of the coefficient of variation of cement activity.

At the same time, at the stage of mixing the concrete mix, after introducing the first part of the mixing water (30% of the calculated amount) into the concrete mixer, a conductivity sensor 54 is applied, the signal from which is fed to the converter 55, from which the signal in the form of electric current voltage U goes to the differential - Ator 56, where the conversion is performed

ai o.

signal c. Signal corresponding to l

change the rate of growth of electric

Hey ......

stress

at

arrives at comparator

57, where, by comparison with a zero potential, and 0 the instant of introduction of the second portion of the mixing water (70%) of the calculated amount is determined. From the comparator 57, an electrical signal is supplied to the block 58 for controlling the supply of water to the gate and to the block 21 of chemical additives. This signal is perceived by blocks 57 and 21 as a command for supplying the second portion of the mixing water and the introduction of the plasticizer. The actuator 59 and the solenoid valve 60 implement the two-stage concrete mix preparation mode. The concrete mixture is then agitated again.

A device for controlling the process of manufacturing concrete and reinforced concrete products ensures optimization of the technological process, a given level of product quality for durability, and economy of the heat transfer medium.

Claims (1)

The invention The device for controlling the process of manufacturing concrete and reinforced concrete products according to ed. St. 1416320, distinguished by the fact that, in order to improve the quality of control, it is equipped with a concrete conductivity sensor with a converter, a differentiator, a comparator and a gate water supply control unit with an actuator of an appropriate regulator, and the conductivity sensor through serially connected converter and a differentiator is connected to the input of a comparator, the output of which is connected to the input of the gate water control unit and to the input of the block of chemical additives.