Application of Programmable Controller in Fine Coal Filter Press System

introductory

XMZG typeFine Coal Filter PressOn the basis of the original tailing coal filter press, it is further improved and developed, which is a highly efficient dewatering equipment used for dewatering flotation coal in coal preparation plant. The process has more links to be controlled and the system is more complicated. If the traditional relay interlocking control, will make the control system cumbersome, high failure rate, decreased reliability, and maintenance: programmable controller, with its high reliability, strong anti-interference ability, variable control procedures, shellfish have good flexibility, simple programming, easy to use and other characteristics to meet the requirements of the process.

Fine Coal Filter Presscontrol programmes

refined coalfilter pressThe good action includes mechanical, hydraulic transmission and pneumatic three parts, according to the requirements of the dewatering process, the control mainly includes the following aspects:

hydraulic system

(1) Pressing the filter plate: This machine adopts high and low pressure double pump system, at the beginning, double pumps supply oil at the same time, start the main cylinder, push the pressing plate, the filter plate quickly in place, to be tight to the filter plate, the pressure of the system rises to reach the electric contact pressure gauge pre-set grading pressure PfH, the low-pressure system automatically unloading 'only a small flow of high-pressure pump to drive the main cylinder to continue to slow top pressure, to be up to the upper limit of the electric contact pressure gauge pressure stamp, the motor automatically stops. When the upper pressure limit of the electric contact pressure gauge is reached, the motor stops automatically.

(2) keep pressure: for insurance reasons, 'the machine is also set up with automatic make-up pressure function, make-up pressure by another electric contact pressure gauge control, its upper limit pressure and Pg the same, the lower limit pressure is the minimum holding pressure of the cylinder, when for various reasons, the main oil red in the filtration is not the end of the pressure drop to the minimum pressure, the high pressure pump restarted, the top pressure of the cylinder to the Pg.

pneumatic system

(1) Feeding; when the slurry enters into the feed heel, open the pneumatic butterfly valves 2 and 7, and close the pneumatic butterfly valves when the slurry in the tank reaches the adjusted height of the material level meter. After the filter press is tightened, open the pneumatic butterfly valve. At the same time, open the tank inlet solenoid valve, high-pressure gas into the tank, forcing the slurry quickly into the filter press chamber, through the filter cloth for filtration.

(2) Blowing; after the end of feeding, close the pneumatic butterfly valve, at the same time, open the blowing solenoid valve, high-pressure wind from the centre hole of the filter press into the 'blowing clean into the slurry orifice residual slurry, and at the same time exclude the cake particles formed in the gap in the retained water, so that the cake is further dewatering.

(3) Pneumatic pressing: Close the valve and open the valve at the same time, the high pressure gas is pressed into the side of the rubber diaphragm of the filter plate through the independent inlet pipe, squeezing the filter cake for further dewatering.

(4) Loosen the pressure plate: the main cylinder piston backs up and the filter plate is loosened.

Pull plate unloading: hydraulic motor in the program control, alternately changing forward and reverse, through the sprocket, chain drive pull plate carriage reciprocating movement by pulling the filter cake unloading one by one. 3 control system composition

The electric control system is mainly composed of PLC, control console, low-voltage distribution cabinet, high-voltage switchgear and so on.

(1) Programmable controllers: according to the requirements of on-site control.

PLC choose Japan's Mitsubishi Electric Company produced F2 series programmable-controller F2-64MR, F2 series of products for the building block structure, the combination of modules, easy to replace. In the automatic operation process, PLC according to the programmed automatically and orderly complete the filter press system of feeding, blowing, dehydration, unloading cake and other processes, PLC real-time detection and display of a variety of work signals 'and participate in the control.

(2) Console; the console has the buttons and signal indicators for each material of the system operation. In the automatic process, feeding, blowing, pressing and dehydration are all time-controlled' When the automatic time is almost up, there will be an automatic time prompt, and if the time is considered insufficient, it can be switched manually. In the automatic process, the corresponding indicator light is displayed according to the action.

(3) Switchgear: Low-voltage distribution cabinets and high-voltage switchgear are installed directly in the central distribution room of the workshop.4 Main functions of the system

The console is equipped with two working states: adjustment and automatic. Selection is made by the working state selector switch on the console, and the two states can be switched smoothly.

(1) Adjustment: When the main command switch is pointing to the adjustment position, each action programme can be individually actuated by the corresponding button. This method is usually used during system installation and commissioning, troubleshooting or overhaul.

(3) Automatic: After the adjustment of the single action is correct, automatic operation can be carried out. When the main command switch is in the automatic position, you only need to press the system work button once, and the whole procedure can be completed automatically.

concluding remarks

Programmable controller integrates computer technology, communication technology and automation technology, and has been widely used in various fields of industrial control, of which the coal industry is no exception. Production practice has shown that, due to the use of programmable controllers, the superiority of fine coal filter presses has been fully exploited, which greatly improves the efficiency of dewatering of flotation fine coal in coal processing plants. In addition, PLC is a new type of control device, so it brings great convenience to the site maintenance and operators, and at the same time, it brings significant benefits to the coal plant. It can be foreseen that, with the continuous improvement and development of PLC and the function and structure of XMZG type fine coal filter press, the programmable controller will be more and more used in the fine coal filter press system of the coal processing plant.