The horizontal screw centrifuge (hereinafter referred to as the centrifuge) is used for operations including pre-boot preparation, power-on, shutdown, and operating state adjustment.
The horizontal screw centrifuge (hereinafter referred to as the centrifuge) is used for operations including pre-boot preparation, power-on, shutdown, and operating state adjustment.
1. Prepare before starting:
(1) First check whether the power supply wiring and grounding of the main and auxiliary motors of the centrifuge are safe and reliable, and check whether the belt is loose, the belt is dropped, and the direction of rotation is the same as the direction on the hood.
(2) Check if the oil filling hole on the drum is refueled according to the specified requirements.
(3) Turn the drum by hand to check if there is friction and collision, and whether the rotation is easy.
(4) Install the deep overflow plate of the liquid pool in the appropriate position, and then adjust according to the degree of dry solids discharged.
(5) Cover the upper hood cover, check if the bolts on both sides are tightened, if the bolts of the pulley cover are tightened, and if the pulleys touch the hood.
(6) Set the main motor inverter.
(7) Set the auxiliary motor inverter.
(8) Set the PLC touch screen.
After the setting is completed, the corresponding feed flow rate, dosing flow rate, differential speed and main and auxiliary motor running frequency will be displayed during the running. The flow rate displayed on the touch screen is the calculation flow rate. When writing the operation record, it should be based on the flow rate value displayed by the flow meter. Then, during the operation, according to the degree of dryness and wetness of the solid phase discharged from the centrifuge and the clarification degree of the discharged water, real time Adjust the amount of feed and the amount of dosing.
(9) Before starting the machine, check that the feed pump, clean water pump and dosing pump are safe and in good condition.
(10) Check whether the feed line and the dosing dilution line on the drug dilution device are unblocked.
2, boot:
(1) Operate on the touch screen and turn on the main and auxiliary motors of the centrifuge at the same time. When the main motor runs to 15-20 Hz, it enters the clean water from the feed inlet of the centrifuge until the drain port has clean water flowing out.
(2) When the operating frequency reaches the preset operating frequency, start the dosing pump and check if there is any liquid in the transparent feeding tube flowing into the centrifuge.
(3) Turn on the feed pump and check if there is any material in the feed transparent tube entering the centrifuge.
(4) After running 15~20mim, check whether the solid phase discharged from the slag discharge port is dry, and check whether the discharge water at the drain outlet is clear. If the discharged solid phase is very wet, first turn off the feed pump, then turn off the dosing pump, then turn off the main and auxiliary motors and replace the tank deep overflow plate.
(5) Replace the overflow plate with a larger inner diameter to reduce the depth of the liquid pool and check whether the solid phase discharged is improved. If it is not enough, the working frequency of the auxiliary motor can be increased, the differential rotation speed will become smaller, and the solid phase will be dried, but the clarification of the effluent will be worse.
(6) The centrifuge is in normal operation after meeting the above requirements.
3, shut down:
(1) Turn off the dosing pump.
(2) Close the feed valve.
(3) Turn off the feed pump.
(4) Open the inlet valve, the cleaning valve, and rinse the internal solid phase of the centrifuge. The flushing time is until the drain is discharged from the centrifuge drain. If the centrifuge is down for 3 to 5 days, it is not necessary to perform a water rinse step.
(5) Turn off the main motor and auxiliary motor.
4, run:
(1) The working current of the main motor of the centrifuge can be controlled to about 85% of the rated current of the motor to ensure that the centrifuge will not be overloaded.
(2) Check and record the feed flow rate, concentration, vibration, main bearing temperature, main motor current, auxiliary motor current and torque of the centrifuge every 2 hours. If the centrifuge is lubricated with thin oil, check and record the oil pressure, flow rate, inlet temperature and return temperature of the lubricant. If it is found that it is beyond the normal range, it should be adjusted and processed in time.
(3) If abnormal conditions are found, they should be dealt with in a timely manner and relevant records should be made.
(4) Pay attention to the temperature rise of the bearing housing. If the housing temperature exceeds the ambient temperature of 50 ° C, it will be taken seriously. The lubricating grease inside the bearing is allowed to withstand high temperature 80~120°C. When the temperature exceeds 50°C, the lubricating oil is added to the bearing oiling hole. After 20min, the bearing temperature will drop. If the oil is added for 30min, the temperature is still Can't drop it, stop it and check it.
5, operating state adjustment:
(1) Operating status adjustment principle:
The centrifuge has three adjustable operating parameters: drum speed, differential speed of the screw and drum, and tank depth.
Under normal circumstances, firstly set the drum rotation speed range for the separated materials, and then adjust the differential rotation speed and the overflow plate according to the separation condition of the centrifuge to obtain better separation effect. The adjustment of the differential speed and the overflow plate and the liquid phase clarity and the solid phase moisture generally have the following rules:
A smaller differential speed will reduce the solids moisture content, but the liquid phase clarity will decrease. Larger differential speeds increase the clarity of the liquid phase, but the solids moisture content increases.
A smaller inner diameter overflow plate will increase the clarity of the liquid phase, but the solid phase moisture content will increase. A larger inner diameter overflow plate will lower the solid phase moisture content, but the liquid phase clarity will decrease.
Therefore, when the liquid phase clarity is dominant and the solid phase moisture content is secondary, the deeper tank depth should be used, and the differential speed should not be too small. When the solid phase dryness is dominant and the liquid phase clarity is secondary, a shallower tank depth and a smaller differential speed should be used.
(2) Operating status adjustment procedure:
1) After the centrifuge is operating normally, check the liquid phase clarity and solid phase dryness.
2) If the result does not meet the requirements, first adjust the drum speed and the differential speed to change the effective centrifugal force acting on the material and the average residence time of the solid phase in the drum dewatering zone.
3) If the adjustment of the drum speed and the differential speed cannot make the liquid phase clarity and solid phase dryness meet the requirements, stop feeding, stop according to the shutdown procedure, replace the overflow plate, and change the depth of the liquid pool. Replace the overflow plate program: After the centrifuge is stopped, open the hood, remove the overflow plate one by one from the centrifuge, install the other size overflow plate, then restart the centrifuge according to the start-up procedure and re-feed.
The above operation was repeated until the liquid phase clarity and the solid phase dryness were satisfactory. Keep running.
Keywords: decanter centrifuge
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