SU482544A1 - Device for automatic control of electric heating of reinforcement in the manufacture of prestressed concrete products - Google Patents

Description

sy. This operation is performed prior to the start of treatment of a given batch of precast concrete products or reinforced reinforcement.

The device works as follows.

Unit 1 sets the initial temperature of the valve in degrees (as a rule it is the ambient temperature), as a result, the output ti ° comes from the output of the unit 1 to the input of the subtractor unit. Unit 2 sets the required temperature of the valve. From the output of the setting device 2, a signal of 2 ° is fed to the input of the unit 5. The setting device 3 sets the heat capacity of the reinforcement material. From the output of the setting device 3, the signal is fed to the input of the multiplication unit 6. The setting unit 4 sets the mass of the heated armature in grams, from the output of the setting unit 4 the signal enters the input of unit 6. From the output of subtraction unit 5, the difference between the signals enters the input of unit 6. The product of the signals supplied to the inputs of unit 6 Q cm () is the amount of heat in calories x required to heat the reinforcement. The signal Q from the output of multiplier 6 is fed to the input of block 8, where it is divided by a factor of 0.24 and, with the latter, P is fed to the input of block 12, a signal comparison (signal

P - --- is the amount of electricity required to heat the reinforcement).

Thus, depending on the preset values, a signal P, equal to the amount of electricity required to heat the corresponding fixture, is continuously received from the output of the division unit to the input of the signal comparison unit. From the output of the voltage sensor 9 connected to the power supply of the electrical heating apparatus, the signal U is fed to the input of the multiplication unit 7. From the output of current sensor 10 included in the load circuit, the signal / is fed to the input of block 7, which continuously adjusts the multiplication operation / f /, as a result, from the output of block 7 to the input of integrator 11, the signal W continuously flows. As a result of integrating the input signal from the output The integrator AND to the input of the signal comparison unit 12 receives an increasing signal AP. When the equality of signals AP P arriving at the inputs of the comparison unit of signals 12 at the input of the latter is achieved, a pulse appears, which is fed to the input of the control unit and is a command to turn off the electrical heating equipment. The equality of the signals of the AR I, where P is the specified amount of electricity, and AP is the consumed amount of electricity, is a sign of heating the valve to a predetermined temperature of 2 °.

Subject invention

Device for automatic control of electric heating of armature in the manufacture

0 prestressed concrete products containing a heating temperature setter, a control unit and an integrator, characterized in that, in order to increase reliability, it is additionally equipped with heat capacity, mass and initial temperature controllers of the fittings, current sensors and voltage of the electrical circuit of the fittings, subtraction units , divide, multiply, and compare, with master outputs

The initial temperature of the fittings and the heating temperature are connected to the subtraction unit, the output of which is connected to one of the inputs of the first multiplication unit, the other two inputs of which are connected to the outputs of the setpoint of the heat capacity and the mass of the fittings, and the output of the multiplication unit, through the division unit the second input of which is connected via an integrator to the output of the second multiplication unit, the inputs of which are connected to the output of current sensors and the voltage of the electric fitting circuit, the output of the comparison unit is connected to the input Lok control.

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