SU810270A1 - Hammer mill control system - Google Patents

Description

one

The invention relates to the field of regulating the systems of dust preparation of boiler units of thermal power plants.

A known system for automatically controlling the performance or loading of the mills, which contains a loading controller with an impulse sensor characterizing the loading of the mill with raw fuel, correcting this impulse by the level of dust in the intermediate bunker, for which the known device contains a level gauge of dust in the intermediate bunker connected to load controller via converter 1.

The disadvantage of this system is low efficiency at low loads of the boiler, when the hammer mill works underload, and, consequently, with an increased specific energy consumption for grinding coal. In addition, at elevated loads of the boiler, it is impossible to prevent the coal mill from falling down.

A hammer mill control system is also known, which includes a bunker, an electric motor feeder, a mill electric motor, a drying agent supply pipeline, a vacuum mixture temperature sensor, a differentiator, a converter, a performance regulator, and a speed control unit, the electric motor of the feeder, and one of the sensor outputs The temperature of the vacuum mixture is connected through a differentiator to one of the inputs of the 2J capacity control.

However, in this system there is no stock of productivity, which leads to coal mills in the event of an overload.

The purpose of the invention is to increase the reliability of the system.

This is achieved by the fact that the hammer mill control system contains a bunker, a motor feeder, a mill electric motor, a drying agent supply pipe, a vacuum mixture temperature sensor, a differentiator, a speed controller, and a Vras speed control unit, the motor of the feeder, and one from the outputs of the temperature sensor of the dust mixture is connected via a differentiator to one of the inputs of the capacity controller, equipped with a comparison element, averaging device and sensors The power of the mill motor, the other output of the temperature sensor of the dust mixture is connected via a converter to another input of the capacity controller, the output of which is connected to one of the inputs of the averaging device, and the speed sensor

The mill motor is connected to another input of the averaging device through the comparison element, the output of which is connected to the control unit of the rotation speed of the motor of the feeder.

A schematic diagram of the regulation of a hammer mill is depicted in the drawing.

The proposed system includes a raw coal bunker 1, a feeder 2, a feeder electric motor 3, a chute 4, a hammer mill 5, a mill electric motor 6, a drying agent duct 7, a drying agent, a dust pipe 8, a mixture temperature sensor 9, a converter 10, a differentiator 11, a capacity regulator 12 , the control unit 13 of the rotation speed of the electric motor of the feeder, the power sensor 14, the element of comparison 15 and the averaging device 16, which are a circuit for limiting the output of dust depending on the power of the electric motor. The meliyits performance regulator can be implemented but any of the known schemes (not shown in the drawing).

The effect of the proposed regulation system is based on the use of the change in fuel supply to the mill as a regulating effect, as well as on limiting the amount of fuel supplied depending on the maximum permissible power of the electric motor of the mill.

Raw coal from the hopper 1 nostunaet on the feeder 2 raw coal (PSU). The speed of movement of the conveyor belt of the PSU is determined by the speed of the electric motor 3. The required amount of coal and after iicy along stream 4 enters the hammer mill 5, the rotor of which rotates at a constant speed by the motor of the Meliitsa 6. for the fuel in the pipeline 7 to the mill 6 is supplied drying an agent, for example, hot gases from the gas duct of the boiler unit, and the dust-gas mixture is removed from the mill and dust pipe 8 to the dust tank (not shown).

The temperature of the dust, equal to the temperature of the dust mixture, is measured by a thermocouple sensor 9, an electrical signal from which (proportional to this temperature), is fed to the converter lU and to the differentiator 11. Then both signals are fed to the input of the regulator 12, which through the control unit 13 acts on a change in the speed of rotation of the rotor of the electric motor 6 and thereby a change in the supply of coal to the mill 5.

The signal of the power of the electric motor of the mill 6, measured by the power sensor 14, goes to the reference element 15, and after it goes to the averaging device 16, in which it is continuously stored, calculating the average power L / cf for a given time interval (for example c) and

comparison with the maximum allowable power value. If the calculated average is more than the allowable, i.e.

Comparison element 15 generates a command signal to the device 16, which disconnects the "more regulator 12 circuit, according to which

The rotor speed control unit 13 of the electric motor 3 is given a signal to add. Thereby a ban is imposed on increasing the feed of coal to the mill 5.

If during the next time interval, for example, A 30 sec, the calculated average power of the mill motor is less than acceptable, device 16 turns on the "more regulator 12 back" circuit and allows the flow of signals "add from regulator 12 to block 13 and further to electric motor 3. At the same time, the performance regulator of the mill, affecting the hot

gases (not shown in the drawing), maintains the drying capacity of the mill in accordance with the load of the boiler.

formula of invention

Hammer mill control system, including a bunker, electric motor feeder, mill electric motor, feed agent supply line,

temperature sensor, a vacuum mixture, a differentiator, a coolant, a performance controller and a control unit for the rotation speed of the motor of the feeder, one of the outputs of the temperature sensor

The vacuum mixture is connected via a differentiator to one of the inputs of the capacity controller, characterized in that, in order to increase the reliability of operation, it is equipped with a comparison element,

an averaging device and a power sensor of the MI motor, the other output of the temperature sensor and the mixture is connected via a converter to another input of the performance controller, the output of which is connected to one of the inputs of the averaging device, and the power sensor of the mill electric motor is connected to another input of the averaging device, the output which is connected to the control unit of the rotation speed of the electric motor of the feeder.

Sources of information taken into account in the examination

1. USSR author's certificate No. 318787, cl. F 23N 1/00, 70.

2. Automatic control system for open-circuit dust systems at the Irkutsk CHPP-6, report of the Central Design Engineering Center No. 202710 / 0-9400, 1977

(prototype).

Claims (1)

Claim A hammer mill control system containing a bunker, a motor feeder, a mill motor, a drying agent supply pipe, a vacuum temperature sensor, a differentiator, a converter, a capacity regulator and a control unit for the rotation speed of the electric motor; one of the outputs of the dust mixture is connected to one of the sensors. from the inputs of the performance regulator, characterized in that, in order to improve the reliability of operation, it is equipped with an element the averaging device and the mill motor power sensor, the other output of the dust mixture temperature sensor is connected via a converter to another input of the performance regulator, the output of which is connected to one of the averaging device inputs, and the mill electric motor power sensor is connected to another averaging device input, the output of which is connected to the control unit of the rotation speed of the electric motor of the feeder.