Submersible pump is the motor and pump directly into the water work together into the water lifting equipment, has a simple structure, easy maintenance and management, high reliability and benefits of automation control, widely used in urban water supply and drainage industry and mechanical and electrical irrigation and drainage engineering. In the use of attention to check maintenance, can effectively extend the life of the pump, improve pump efficiency.
1 use of submersible pumps
1.1 Selection of submersible pumps
Submersible pump in use should be based on their own characteristics, the correct selection, selection of the main consideration flow, head, installation, etc., should be based on the actual water conditions, working hours and pump water requirements to select the pump head and flow. Pump head is too low, the pump flow is not enough or no water; head is too high, high-lift pump for low head work, there will be running when the flow is too large, the motor is too high, the pump head is too low, Overload, if the long run, the motor temperature, winding insulation will gradually aging, or even burn the motor.
1.2 submersible pump into operation before the inspection
The submersible pump should not be placed horizontally or directly at the entrance of the sewage, but according to the scene to determine the appropriate submersible pump from the bottom of the appropriate height, so that the pump inlet is suspended by the sediment or suspended. The position of the low-level float switch must be properly adjusted to avoid the accumulation of mud when the level is too low so that the water level or accuracy can not be measured by the level gauge, whichever is the lowest The water level ensures that the submersible pump is still submerged. Usually pay attention to timely clean up the bottom of the sludge and debris, especially the large volume of debris, the new use of the pump should pay particular attention to construction waste cleaning, and maintain a period of close inspection.
Care should be taken to check the cable for damage and scratches, with special attention to seal and cable entry is intact, check the lifting chain and the cable is hanging as required fixed, with particular attention to the cable and the hoisting of the hanging chain Radian can not be too large, otherwise the cable, lifting chain and pump casing will be worn. With 1 000V shaking table to check the three-phase insulation resistance of the motor, the minimum not less than 1MΩ. Check the oil level is in line with the requirements of the pump leakage, thermal protection and other sensor components signal is normal, the pump is intact.
After the new pump or the overhauled pump is put into operation, the impeller should be manually turned to check whether the rotation is flexible, and turn on the power to confirm, pay attention to the pump dry running time is strictly prohibited for more than 30s. Check whether the electrical wiring has been installed and commissioned, and can run reliably. Make sure the supply voltage is normal and the power supply is connected correctly.
1.3 Submersible pump operation when the precautions
Large submersible pumps must be used to start the buck, soft start or variable frequency start to reduce the impact on the grid and submersible pump itself. Submersible pumps generally have a certain requirement on the solid content and particle diameter, pH value, water temperature, chloride ion content, etc. of the fluid to be transported, pay attention to the use, otherwise there will be pump overload, corrosion and other phenomena, thereby reducing Pump mechanical seal performance and shorten the life of the motor. Motor main circuit power, if the motor does not turn, should be immediately shut down to prevent the motor stuck for a long time power and burned. After the first installation or maintenance of submersible pumps put into operation, the test machine can only start on site in situ, in order to observe, start after the start of operation, should strengthen monitoring and observation of water level changes and pump outlet flow. Normal operation of the submersible pump should be smooth, no vibration and abnormal sound. Submersible pump must be submerged into the water running, and start and stop should not be too frequent, the number of starts is generally not more than 5 times / h (specific times and power and submersible pump type), and require uniform spacing, restart should be shut down 3 ~ 5min After the water hammer to prevent damage to the submersible pump.
2 submersible pump maintenance
Because of the submersible pump working environment in the water, some anomalies are difficult to detect. In order to ensure the reliable operation of submersible pumps, to extend the service life, the need for regular maintenance of submersible pumps. Usually do check the submersible pump running voltage, current and outlet flow, and check the cable and lifting chain for wear, with or without a fixed, and timely removal of the cable winding garbage, monthly inspection submersible pump to ground insulation resistance , Resistance shall not be less than 1MΩ. Check regularly that the electrical protection circuit and other protective devices are working properly. Regularly tighten the terminals, especially the power cable terminals, so as not to heat the terminal burn caused a major accident. To ensure the safe operation of the submersible pump, level gauge and dry protection float switch should be checked regularly to ensure normal use.
When servicing the pump, always disconnect the main power supply first. To prevent submersible pumps in the automatic water level control from the start caused by physical equipment safety incidents. Check the main cable and control cable with or without aging cracking, the need for repair or replacement; Check the lifting chain for wear and damage, whether the pump, the pump body to check whether the main cable and control cable aging cracking, Whether the corrosion, whether the need for corrosion; check the mechanical seal is intact; check the oil room with or without water, if the water needs to check the reasons for troubleshooting and replacement of lubricating oil; check impeller wear or cavitation, whether required repair or replacement; Check whether the seal between the pump impeller and the pump ring gap is too large to be replaced; pump shaft rust deformation or wear; motor bearing wear and tear is short of oil; motor winding insulation layer with or without signs of aging; Insulation resistance to ground is too low ; Whether the three-phase winding resistance is balanced; whether the rotor between the stator and rotor damage traces; junction box with or without water; temperature, leakage protection components are normal, the motor inside and outside the fastening screw loosening, cooling jacket and circulating water pipe Check whether the main contactor of the protection circuit is oxidized or burr; whether the thermal relay equipment is correct; whether the level gauge of the pump house is accurate; whether the floating ball action is reliable or not; if there is no debris, ; Pump mouth and the surrounding sediment deposition or blockage; pump whether the need for water and dredging. Prolonged use of submersible pumps, should be made of water, clean and dry, the upright on dry and ventilated indoor storage.
Typical Cases
Hefei Wangtang sewage treatment plant inlet pump room configuration 4 sets of Swedish Flygt C3306-665 submersible pump, motor power 75KW, rated head 13m, flow 1 450m3 / h, speed 980rpm, protection class IP68, 4 sets of submersible pumps
3 1 equipment, three pumps are soft starter start, a frequency control, in order to adjust the water flow according to the incoming water.
The pump pump coaxial, compact structure, the use of dual-rail automatic installation system, installation and maintenance is very convenient. Adopting non-clogging closed-flow impeller, the maximum particle diameter of 100mm, with a large channel area, through the large particles and entanglement, reduce the risk of congestion, over-current performance. The cable of the motor is able to withstand medium erosion, the cable is protected with flexible metal hose. Stator insulation class F (155 ℃), according to the standard, the motor stator into the PTC - thermistor overload protector. Submersible pumps are equipped with a cooling system, the impeller blade back to the cooling water around the stator room cycle, can also be used independent cooling system, the external cooling jacket and volute is not connected directly from the outside of the introduction of cooling water. This cooling system is particularly effective when the temperature of the pumped liquid is elevated or is likely to run dry. Between the motor and hydraulic components with double mechanical seal to prevent the liquid into the motor chamber, the upper layer of graphite / tungsten carbide, the lower tungsten carbide / tungsten carbide. A replaceable seal ring is provided between the pump impeller and the pump to keep the pump running at optimum efficiency.
The pump body is equipped with a number of protection elements such as the stator-room float switch, the PTC thermistor in the stator windings, the PT100 sensor in the main and support bearings, the float switch in the junction box, CLS leakage in the oil chamber Sensors, these sensors play a multiple protection of the pump, when the submersible pump mechanical seal damage, oil room water more than 1/3, the motor stator oil into the water, stator windings or bearing temperature rise too high or the motor junction box into Water, the relevant protection components will send a signal to the pump integrated protector, integrated protector will display a fault signal and cut off the main circuit pump power to protect the submersible pump.
The submersible pump is one of the most important equipments in the WWTP. It must be kept on for 24 hours to realize the automatic opening and closing of the submersible pump. The submersible pump can be automatically monitored and drained to protect the submersible pump and save energy and reduce the cost. Purpose, installed in the inlet pump room ultrasonic level meter and to prevent the submersible pump dry running low level float switch. Submersible pumps can achieve four kinds of control:
① on-site control. The local control box is equipped with selector switch, signal indicator and on-site emergency stop button. When the selector switch is in the "LOCAL" position, the pump can be started directly. When put in "REMOTE" position, Center control room automatic water level control, placed in "0" position, the device can not open.
② MCC control mode. General PLC control system failure or level gauge does not work, you can open or stop the switchgear.
③ automatic control. As the pump level liquid level analog signal has been introduced into the PLC, the operator can set the number of submersible pumps according to the water level of the pump house and select the high and low speed operation of the submersible pumps, reasonably control the inflow flow rate and control the pump room water level, To achieve economic operation, while the cumulative running time according to the pump automatically turns the pump running.
④ dry protection control. Low-level float switch signal into the submersible pump control and protection circuit, once the pump below the set water level, regardless of the submersible pump in what kind of control, will be forced to stop running to prevent submersible pump dry operation burned.
4 Conclusion
Understand the use of submersible pumps attention to strengthen maintenance, through advanced automation and control measures to reduce the pump failure rate, to extend the life of the pump to improve pump efficiency, energy conservation, to ensure safe and reliable operation of submersible pumps.
The pump pump coaxial, compact structure, the use of dual-rail automatic installation system, installation and maintenance is very convenient. Adopting non-clogging closed-flow impeller, the maximum particle diameter of 100mm, with a large channel area, through the large particles and entanglement, reduce the risk of congestion, over-current performance. The cable of the motor is able to withstand medium erosion, the cable is protected with flexible metal hose. Stator insulation class F (155 ℃), according to the standard, the motor stator into the PTC - thermistor overload protector. Submersible pumps are equipped with a cooling system, the impeller blade back to the cooling water around the stator room cycle, can also be used independent cooling system, the external cooling jacket and volute is not connected directly from the outside of the introduction of cooling water. This cooling system is particularly effective when the temperature of the pumped liquid is elevated or is likely to run dry. Between the motor and hydraulic components with double mechanical seal to prevent the liquid into the motor chamber, the upper layer of graphite / tungsten carbide, the lower tungsten carbide / tungsten carbide. A replaceable seal ring is provided between the pump impeller and the pump to keep the pump running at optimum efficiency.
The pump body is equipped with a number of protection elements such as the stator-room float switch, the PTC thermistor in the stator windings, the PT100 sensor in the main and support bearings, the float switch in the junction box, CLS leakage in the oil chamber Sensors, these sensors play a multiple protection of the pump, when the submersible pump mechanical seal damage, oil room water more than 1/3, the motor stator oil into the water, stator windings or bearing temperature rise too high or the motor junction box into Water, the relevant protection components will send a signal to the pump integrated protector, integrated protector will display a fault signal and cut off the main circuit pump power to protect the submersible pump.
The submersible pump is one of the most important equipments in the WWTP. It must be kept on for 24 hours to realize the automatic opening and closing of the submersible pump. The submersible pump can be automatically monitored and drained to protect the submersible pump and save energy and reduce the cost. Purpose, installed in the inlet pump room ultrasonic level meter and to prevent the submersible pump dry running low level float switch. Submersible pumps can achieve four kinds of control:
① on-site control. The local control box is equipped with selector switch, signal indicator and on-site emergency stop button. When the selector switch is in the "LOCAL" position, the pump can be started directly. When put in "REMOTE" position, Center control room automatic water level control, placed in "0" position, the device can not open.
② MCC control mode. General PLC control system failure or level gauge does not work, you can open or stop the switchgear.
③ automatic control. As the pump level liquid level analog signal has been introduced into the PLC, the operator can set the number of submersible pumps according to the water level of the pump house and select the high and low speed operation of the submersible pumps, reasonably control the inflow flow rate and control the pump room water level, To achieve economic operation, while the cumulative running time according to the pump automatically turns the pump running.
④ dry protection control. Low-level float switch signal into the submersible pump control and protection circuit, once the pump below the set water level, regardless of the submersible pump in what kind of control, will be forced to stop running to prevent submersible pump dry operation burned.
4 Conclusion
Understand the use of submersible pumps attention to strengthen maintenance, through advanced automation and control measures to reduce the pump failure rate, to extend the life of the pump to improve pump efficiency, energy conservation, to ensure safe and reliable operation of submersible pumps.
Manufacturers recommend: Shenlong stainless steel deep well submersible pump
Keywords:Large submersible pumps, use, maintenance
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