The industrial structure is optimized, and the low energy consumption and high added value industries are developing rapidly. The added value of the low energy consumption industries in the building materials industry will reach 42%; The production process structure of cement flat glass was optimized. The proportion of new dry process cement reached 80%, and the proportion of float glass process increased to 86%; The organizational structure of the enterprise was optimized. The clinker output of the top 60 cement enterprises has accounted for more than half of the total output. The annual clinker production capacity of the top 20 cement enterprises has reached 45%. The output of flat glass of large enterprise groups accounts for 73% of the total national output. The output of large and medium-sized technical glass enterprises accounts for 72% of the total technical glass production.
PLC on float glass production line
In the glass industry, PLC is mainly used for the control of production equipment and production line, such as roller table, cutting machine, stacking machine, glass deep processing washing machine and glass cold end line in glass production. Now we will focus on the application of PLC in float glass production line.
The vertical stacker is one of the important equipment applied to the cold end of the float glass production line. It is a special equipment for stacking the glass transported to the sheet taking roller table onto the roller rack of the step back trolley through the suction cup sheet taking machine. There are two key technologies for the vertical stacker in the float glass production line, namely, the overturning movement from the sheet taking roller table to the roller carrier, and the step back movement of the trolley after stacking a piece of glass. The automatic control of these two actions is realized through PLC.
The servo control system is composed of PLC controller, servo driver and servo motor to control the movement of the four-bar mechanism for glass handling. Driven by the driver, the servo motor drives the four-bar mechanism through the reducer. The target position is fed back to the PLC controller by the feedback signal of the absolute value encoder. The rotation accuracy is guaranteed under the control of the PLC controller. When the mechanism rotates, the encoder is used for position feedback and positioning is accurate.
Small PLC is widely used in cement production equipment
The automatic control of cement plant production process includes sequence control and process control. Sequence control is mainly used to realize group starting, stopping of motors and electric control equipment that enter PLC in the whole plant, as well as mutual interlocking during equipment operation; The process control is mainly to collect the temperature, pressure, speed, flow, material level and other process parameters of the whole plant entering the PLC, and adjust and control the production process by setting the valve opening and speed.
In the cement industry, PLC is mainly used for the control of production lines and production equipment, such as cement production lines and cement production mills, raw meal mills, clinker mills, converters, etc. The cement production line is dominated by large PLC, while the production equipment in the cement industry is dominated by small PLC.
Taking the application of PLC in bag type dust removal system of dry cement production line as an example, the PLC control system has replaced the traditional relay control system due to its powerful function, high reliability, simple programming, and use. The bag type dust removal control system is more reliable and easy to maintain.
At present, the off-line long bag pulse bag filter is mainly composed of upper box, middle box, ash hopper, filtering system, ash unloading system, injection system and control system. The dusty gas enters the filter chamber from the air inlet of the ash hopper, and the coarse particles directly fall into the ash hopper or ash bin. The dusty gas is filtered by the filter bag, and the dust is retained on the bag surface. The purified gas is discharged into the atmosphere by the fan through the bag mouth to the clean air chamber. When the dust of the filter bag increases continuously, causing the equipment resistance to rise to the set value, the PLC outputs the signal, the control signal starts to work, and the pulse valve opens, so that the compressed air can blow the filter bag through the nozzle to remove the dust. Under the effect of the reverse air flow, the dust attached to the bag surface quickly leaves the filter bag and falls into the ash hopper, and the dust is sent out by the ash valve. After fully considering the time of dust, the poppet valve is opened, the filter bag in the secondary bag chamber returns to the filtering state, and the next bag chamber enters the ash removal state. So it is a cycle until the last bag chamber is cleaned. The ash removal process is automatically controlled by PLC.