The horizontal screw centrifuge (hereinafter referred to as the centrifuge) is a key equipment used in various stages such as pre-startup preparation, power-on, shutdown, and adjustment of operational parameters. Proper operation and maintenance are essential for ensuring efficiency, safety, and optimal performance. Below is a detailed guide on how to operate the centrifuge effectively.
1. **Pre-Startup Preparation**
(1) Inspect the power supply wiring and grounding of both the main and auxiliary motors to ensure they are secure and safe. Check the belt tension and alignment, making sure it is not loose or off-track, and that the rotation direction matches the label on the hood.
(2) Confirm that the oil filling hole on the drum is properly lubricated according to the manufacturer’s specifications.
(3) Manually rotate the drum to check for any friction, collision, or resistance, ensuring smooth operation.
(4) Install the deep overflow plate in the correct position and adjust it based on the dryness of the solids being discharged.
(5) Secure the upper hood cover, ensuring all bolts on both sides are tightened, and check that the pulley cover bolts are also secured and that the pulleys do not touch the hood.
(6) Configure the main motor inverter settings.
(7) Adjust the auxiliary motor inverter accordingly.
(8) Set up the PLC touch screen with the required parameters. Once set, the system will display the calculated feed flow rate, dosing flow rate, differential speed, and motor frequencies. However, always refer to the actual flow meter readings when documenting operational data. During operation, monitor the dryness of the solid phase and the clarity of the liquid discharge, adjusting feed and dosing rates as needed.
(9) Ensure that the feed pump, clean water pump, and dosing pump are in good working condition.
(10) Verify that the feed line and dosing dilution line on the chemical dilution device are clear and unobstructed.
2. **Startup Procedure**
(1) Use the touch screen to start the main and auxiliary motors simultaneously. When the main motor reaches 15–20 Hz, begin feeding clean water through the inlet until clean water flows out from the drain port.
(2) Once the operating frequency stabilizes, activate the dosing pump and confirm that liquid is flowing through the transparent feed tube into the centrifuge.
(3) Start the feed pump and check that material is entering the centrifuge through the transparent feed tube.
(4) After running for 15–20 minutes, inspect the dryness of the solids at the discharge port and the clarity of the effluent. If the solids are too wet, stop the feed pump first, then the dosing pump, and finally the main and auxiliary motors. Replace the overflow plate if necessary.
(5) If the solids remain too wet, replace the overflow plate with one of a larger inner diameter to reduce the liquid pool depth. This may improve the dryness of the solids. If the effect is still insufficient, increase the auxiliary motor frequency to reduce the differential speed, which can enhance solid drying but may lower the clarity of the effluent.
(6) Once the desired performance is achieved, the centrifuge is considered to be in normal operation.
3. **Shutdown Procedure**
(1) Turn off the dosing pump.
(2) Close the feed valve.
(3) Stop the feed pump.
(4) Open the inlet and cleaning valves to flush the internal components of the centrifuge. Continue rinsing until clean water flows out from the drain. If the centrifuge will be idle for 3–5 days, this step can be skipped.
(5) Finally, turn off the main and auxiliary motors.
4. **Operation Monitoring**
(1) Keep the main motor current within approximately 85% of its rated value to avoid overload.
(2) Every two hours, check and record the feed flow rate, concentration, vibration levels, bearing temperature, main and auxiliary motor currents, and torque. If the centrifuge uses thin oil lubrication, also monitor oil pressure, flow rate, and inlet/return temperatures. Any deviations from normal ranges should be addressed immediately.
(3) If any abnormal conditions occur, take corrective action and document the issue.
(4) Monitor the bearing housing temperature. If it exceeds 50°C above ambient temperature, apply additional lubricant to the bearing oiling point. After 20 minutes, the temperature should drop. If it remains high after 30 minutes, stop the machine and perform a full inspection.
5. **Adjustment of Operating Parameters**
(1) **Principle of Adjustment**: The centrifuge has three main adjustable parameters: drum speed, differential speed between the screw and drum, and the depth of the liquid pool.
Under normal conditions, set the drum speed based on the material being processed, then fine-tune the differential speed and overflow plate to achieve the best separation results.
- A lower differential speed reduces solid moisture but decreases liquid clarity.
- A higher differential speed increases liquid clarity but raises solid moisture.
- A smaller overflow plate diameter improves liquid clarity but increases solid moisture.
- A larger overflow plate diameter reduces solid moisture but lowers liquid clarity.
When clarity is the priority, use a deeper liquid pool and avoid too low a differential speed. For drier solids, use a shallower pool and a lower differential speed.
(2) **Adjustment Procedure**:
1) After startup, assess the liquid clarity and solid dryness.
2) If the results are unsatisfactory, adjust the drum speed and differential speed to influence the centrifugal force and retention time of solids in the dewatering zone.
3) If adjustments fail to meet requirements, stop feeding and follow the shutdown procedure. Replace the overflow plate and reconfigure the liquid pool depth. To replace the overflow plate, open the hood, remove the existing plate, install a new one, restart the centrifuge, and resume feeding. Repeat this process until the desired performance is achieved.
Keywords: decanter centrifuge
Source: http://news.chinawj.com.cn
Submission: http://news.chinawj.com.cn
Co-extrusion polyolefin elastomers (POE) abrasion resistant inner layer plastic composite pipes is characterised by taking co-extrusion thermoplastic polyolefin elastomers as the abrasion resistant inner layer, using a combination of steel wires (or glass fiber) reinforcements and high-density polyethylene. In addition to good workability and physical and mechanical properties as HDPE pipes, such pipes have good wear resisting performance. Co-extrusion abrasion resistant composite pipeline is a kind of anti-abrasion pipe with high cost-effective performance.
Wear Resistant Composite Pipe,Wear Resistant Lined Steel Pipe,Wear Resistant Composite Fire Pipe,High Voltage Resistance Pipe Hdpe
SHANDONG EASTERN PIPE CO., LTD. , https://www.dfuhmwpe.com