SU846540A1 - Method and device for automatic control of thermal treatment of concrete and ferroconcrete articles - Google Patents

Description

(54) METHOD FOR AUTOMATIC REGULATION OF THE PROCESS OF HEAT TREATMENT OF CONCRETE AND REINFORCED CONCRETE PRODUCTS AND DEVICE FOR ITS IMPLEMENTATION

The invention relates to the automatic regulation of thermal

.processes and can be used in the heat treatment of concrete and concrete products and structures.

There is a method of automatically regulating the process of heat treatment of concrete and reinforced concrete, according to the maximum allowable temperature of the heat transfer fluid with the introduction of correction by isothermal heating, controlled by a differentiated contraction signal determined by the vacuum in a sealed vessel with the working concrete mix, placed in the heat exchange unit and placed in the heat exchanging unit. for its implementation, comprising a sensor, a software controller, an actuator, a valve, a temperature difference meter for the medium and the product, pressurized vessel with working concrete mix), t-gate and discrete differentiator ClU

The disadvantage is that this method and device do not correct the heat treatment process depending on the changing properties of the processed products.

The closest to the present proposal is a method for automatically controlling the process of heat treatment of concrete and reinforced concrete products, including changing the set rate of ascent and lowering the temperature by applying pulses with a frequency determined by the calibration curve of the transition function of properties

10 processed products, and a device for its implementation, which contains a pulse generator, a pulse recalculation unit, a correction unit, and, according to the number of heat treatment channels, thermostats and setters and actuators, which are connected through the blocking unit to the input of the control unit. nor C22.

However, the reliability of this method

The control of heat treatment of products and the device for its implementation is insufficient, since in a number of cases there are violations of the heat treatment regimes, leading to an increase in its duration and to the occurrence of temperature stresses in the concrete body, causing destruction and reduction in the quality of products. Such violations include the failure to comply with the task signal change algorithm due to

failures of the environmental sensor under the influence of interference (voltage disappearance, etc); failure of the device to perform a predetermined heat treatment mode, for example, if the supply of heat carrier J is abnormally discontinued, the initial value of the signal specifying the initial temperature of the control object depending on the conditions of concrete preparation, ambient temperature and thermal unit, etc. does not match.

This method and device do not allow to automatically set the initial value of the reference signal to be equal to the actual initial temperature of the control object, which also reduces their reliability.

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

This goal is achieved by the fact that in the method of automatic control of the process of heat treatment of concrete and reinforced concrete products, including changing the set rate of ascent and lowering the temperature by applying pulses with a frequency determined by the calibration curve of the transition function of changing the properties of the processed products, the change of the specified speed is additionally corrected raising and lowering the temperature, measuring the change in actual speed, lifting and lowering the temperature, setting the permissible values of different The spins of the set and real speeds, and the correction of the change in the set rate of rise and decrease in temperature is carried out when the difference between the set and actual speeds exceeds the set acceptable value.

In addition, a device for carrying out the method, comprising a pulse generator, a pulse period recalculation unit, a correction unit, and, according to the number of heat treatment channels, thermal sensors and setters and actuators, which are connected via a block to the input of the control unit, a logic divider and a switch are entered; the pulse generator is connected via a frequency divider to a pulse period recalculation unit, the outputs of which are connected to the first inputs of the setters through a correction unit, the output of the control unit is connected to the input of the logic unit, the switch outputs are connected to the second inputs of the setters, and the switch inputs are connected to the output of the pulse generator, the output of the logic unit and the corresponding output of the frequency divider connected to the corresponding input of the blocking unit.

The drawing shows an electrical circuit of the device in which the proposed method is realized.

A device for implementing a method for controlling heat processes comprises a pulse generator 1, a frequency divider 2, a pulse period conversion unit 3, a switch 4, a correction unit 5, setters 6 and thermal sensors 7 according to the number n of heat treatment channels, a blocking unit 8, actuators 9, block 10 control and logic unit 11.

The pulse generator 1, the frequency divider 2 and the pulse period recalculation unit 3 are connected in series, and the outputs of the latter are connected to the controllers b through the correction unit 5. The switch 4 is connected between the generator 1 pulses to the setters b, and is connected to the logic unit 11 and the divider 2 frequency. The enclosing unit 8 is connected with a frequency divider 2 by setting units 6, thermal sensors 7, actuators 9, input and the second output of control unit 10, the first output of which is connected to logic unit 11.

Claims (2)

The control method includes the optimization of the correction signals introduced into the control system by quantizing them with a frequency determined by the form of the calibration curve of the transition function, determined by the change in properties of the processed products. The optimization is carried out by a correction block 5, which, according to the transition function set in its calibration curve, forms the optimal algorithm for changing the frequency of the master input signal during the heat treatment of products, this frequency determines the rate of change of the output signal of the master b, and hence the rate of rise or decrease of temperature. This method implements any temperature change algorithm set and obtained by technologists when studying the properties of processed products of a certain type and their relationship with signals characterizing a certain parameter or indicator of product quality. Thus, the optimum algorithm for temperature change during heat treatment, in the sense of the required criterion of optimality (maximum strength, minimum heat treatment duration, etc.) associated with extreme points on the calibration curve of the measured the parameter (properties) of the product, such as strength, conductivity, concentration, dielectric characteristics, frequency properties, etc. An example of such an algorithm for concrete is the relationship between the temperature regime and the curve of change in the potential of mass transfer. The method also includes the measurement of the difference between the reference signals and the 9-way communications characterizing the correspondingly required and. the actual temperature of the object to be controlled by the control unit 10; when the difference between the reference signals and the feedback of the permissible value (equal to the maximum dynamic adjustment error) is changed, the change of the reference signal (output signal of the setpoint 6) to a value equal to the feedback signal (the signal of the modulator 7). The feedback rate exceeds the permissible value only in case of disturbances in the temperature control process, in which case the reference signal is restored by the feedback signal, thus adapting the temperature control process and the insensitivity of the method to the influence of various kinds of interference is determined.The proposed method is based on the fact that the control objects have constant heating times (thermal inertia), exceeding the main time constant of the control devices, and are natural memory elements, carriers of the reference information, on the basis of which the rapid recovery of information lost for various reasons, is carried out, which is stored in the memory elements (setting units b) of the regulating device. The device works as follows. Pulse generator 1 generates a signal with a calibrated frequency f. , for example equal to 1 kHz. Frequency divider 2 converts this signal into clock pulses with a frequency f, for example equal to 1 Hz, and into a base signal with a frequency f-, for example equal to 0.0.1 Hz. The base signal enters the unit 3 of the recalculation of the period of the pulses, which divides its frequency to the values of f, fj ,. . . , f, which correspond to outputs 1,2 ... k. Corrective unit 5 according to the calibration curve of the transition function, determined by the change in properties of the processed products, is formed from a series of frequencies f, f,. . ., f the optimal algorithm for changing the frequency of the input signal for each setpoint device b. The dials B have two equally-sized inputs and are built according to the pulse counting principle. Therefore, the algorithm for changing their output signals (being the signals of the task U) is determined by the frequency of the input pulses coming from the correction unit 5 or from the switch 4. successively with the period T-7, time ti connects the control unit 10 to the following elements of each control channel: setpoint b, temperature sensor 7 and executive unit 9 (electricity, steam, or other controller) the bearer). The switch 4 also periodically and sequentially switches its outputs to the inputs of the setters 6, and is synchronized with the blocking block 8 of the clock frequency f. When the difference between the setpoint and feedback signals is less than the allowable value (X), the output signal of the logic unit is O (Y-0) and the switch 4 does not pass the generator signal f to its outputs, i.e. a change in the state of the set-points on the second inputs is not carried out. The signal from the pulse generator 1 through 2 frequency divider is fed to the input of the unit 3 recalculation of the period of pulses. Correction unit 5 measures any parameter of objects associated with the calibration curve of transition functions (incorporated in correction block 5), according to a curve, and for each object it selects the optimal frequency from the output of the block, recalculating the period of pulses 3 to first act the inputs of the control points. . The signals from setters b and temperature sensors 7 are periodically and sequentially connected in pairs by a blocking unit 8 to the inputs of control unit 10, which, on these signals, generates a control signal at its second output, which also comes through control unit 8 to control units 9, which store the control value signal (O or 1) until the next contact with the control unit 10. This is how the relay-impulse temperature control of all objects, usual for multichannel systems, is carried out (according to the deviation of the measured temperature value from the set one). From the first output of the control unit 10, the measured difference of the signals X goes to the logic unit 11. Suppose that in one of the control channels at the moment of switching its elements (setpoint b, thermal sensor 7 and actuator 9.) by the blocking unit 8 to the control unit 10, the first output of the last signal X Hdpp. f then signal 1 appears at the output of logic unit 11. This signal acts on. switch 4, which connects the pulse generator 1 (signal fp) to the second input of the corresponding setpoint b, the output signal of which changes until it equals the feedback signal with an accuracy of cf (where is the temperature sensation threshold of 4 by x ). Since the threshold of sensitivity is inherent in all without exception ruled by devices, and in our case regulation d is not an essential feature and can vary 6 required limits (in accuracy), this parameter is not reflected in the claims. So, if Hdog, 3 °, then it is enough for 1 cf 0.3-0.5. Since the frequency of the input knob 6. On the first input is two to three orders of magnitude higher than the clock frequency f, the recovery process of the reference signal has time to complete during the contact time of the control unit 10 with the K-th control channel. And only after the restoration of the signal at the second output of the control unit 10, the control signal is generated by the executive unit 9k. When the logic unit 11 is triggered, its output signal (1) must be memorized, since switching on 1 must occur at different levels of its input signal X (respectively, in Invention 1. Method of automatic control of the heat treatment process of concrete and reinforced concrete products, including a change in the desired rate of rise and decrease in temperature by applying pulses with a frequency determined by the calibration curve of the transition function of changing the properties of the products being processed, We note that, in order to increase the control accuracy, the change in the set speed of rise and decrease in temperature is additionally corrected, the change in the actual rate of rise and decrease in temperature is measured, the allowable values of the difference between the set and real speeds are set, and the correction of the change in the set rate of rise and decrease is carried out when the difference between the specified and actual speeds exceeds the specified allowable value. 2. A device for carrying out the method according to Claim 1, comprising a pulse generator, a pulse period recalculation unit, a correction unit and, according to the number of heat treatment channels, temperature sensors, setters and actuators, which are connected to the control unit through the shrinking unit, that a frequency divider, a logic unit and a switch are entered into it, the pulse generator being connected to the pulse period recalculation unit through the frequency divider, whose outputs are connected to the first inputs through the correction unit through sensors, the output of the control unit is connected to the input of the logic unit, the outputs of the switch are connected to the second inputs of the setters, and the inputs of the switch are connected to the output of the pulse generator, the output of the logic unit, and the corresponding output of the divider. frequency connected to the corresponding input of the blocking unit. Sources of information taken into account in the examination 1.ABTOt CKoe certificate of the USSR (262676 Cl. 04 B 41/30, 1970. 2. Authors certificate of the USSR 370191, cl. From 04 to 41/30, 1970.