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Starting Procedures For Centrifugal Pump
TIME：2024-06-03 Author：admin Views：
Starting procedures for centrifugal pump should be : first of all , open all the inlet valves, shut-off the outlet valves, start the motor, wait until the speed is normal, then gradually open the outlet valve, adjusted to the requird working conditions.The correct operation method of chemical pump can be divided into 3 step, start, run, stop.
● The following preparations should be made before starting:
Check the integrity of the centrifugal pump equipment and the gound bolts of the machine are firm or not.
Remove the coupling cover, as the pump operation steering wheel three turns, check whether the coupling is concentric, whether there is stuck, abnormal sound and other phenomena.
The bearing is filled with oil, the oil level is normal, and the oil quality is qualified, If there is emulsification, the lubricant should be changed.
● Start
Check the leakage of shaft seal, packing seal with a little water dripping is appropriate.
Motor rotation direction is correct.
After the above preparatory work are completed, you can start the motor, wait for the speed is normal , check the pressure and current, and pay attention to vibration and noise. After everything is normal, gradually open the outlet valve, adjusted to the required conditions, note that the idle time should not be more than 3 minutes to close the valve.
● Run
During operation, the main is a itnerant inspection, which is checked:
Check the bearing
1.Bearing temperature should not exceed 75℃.
Whether the pump and motor have large vibrations.
1. The centerline of the shaft of the pump and the motor is not centered.
2. The foot bolt of the pump or the motor is loose, or the foundation is not secure.
3. The mass of the rotor is not balanced
4. The pump is running in small flow, which produces radial force, backflow, cavitation.
Whether the seal working is normal.
1. The seal will not drip during normal operation.
2. If there is a cooling water unit, check for proper water flow.
● Stop
The centrifugal pump should be stopped first by closing the outlet valve to prevent the backstop valve from failing, resulting in pressure water from the outlet pipe backing up into the pump, causing the impeller to reverse, resulting in damage to the pump.
If the inertia of the pump is small when it is stopped, the pump stops very soon after the power is cut off, it means that there is a friction or eccentricity phenomenon in the pump.
Centrifugal pump start, run, stop the three steps are very important, but the most important is the outlet valve adjustment.
If the suction state, the outlet valve opening can be relatively large, if the backflow state, the outlet valve opening can be relatively small. The outlet valve adjustment point closer to the design point of the pump the better, so that the actual flow state and the theoretical design close to coincide with the pump's high operating efficiency, saving resources. Because the pump's high efficiency point are near the design point, of course, ultimately to the current is not overloaded as a prerequisite.
When centrifugal pump start, the pump export pipeline is not water, so there is no pipeline resistance and lifting height resistance, after the pump start, the pump head is very low, the flow is very large, at this time the pump motor shaft power output is very large according to the pump performance curve, it is very easy to overload, it will make the pump motor and wiring damage, so start to shut down the export valve, in order to make the pump run normally.
● The following preparations should be made before starting:
Check the integrity of the centrifugal pump equipment and the gound bolts of the machine are firm or not.
Remove the coupling cover, as the pump operation steering wheel three turns, check whether the coupling is concentric, whether there is stuck, abnormal sound and other phenomena.
The bearing is filled with oil, the oil level is normal, and the oil quality is qualified, If there is emulsification, the lubricant should be changed.
● Start
Open the exhaust valve and inlet valves , the outlet valve is off state, wait for water to come out of the exhaust valve, shut off the exhaust valve, and open the valve of pressure gauge at the same time.
Check the leakage of shaft seal, packing seal with a little water dripping is appropriate.
Motor rotation direction is correct.
After the above preparatory work are completed, you can start the motor, wait for the speed is normal , check the pressure and current, and pay attention to vibration and noise. After everything is normal, gradually open the outlet valve, adjusted to the required conditions, note that the idle time should not be more than 3 minutes to close the valve.
● Run
During operation, the main is a itnerant inspection, which is checked:
Check the bearing
1.Bearing temperature should not exceed 75℃.
2.The bearing room should not be filled with water and impurities, and the oil should not be emulsified or blackened.
3. When rolling bearings are lubricated with thin oil, the oil level should not be lower than the center line of the oil mark.
4. Whether there is a strange sound, rolling bearing damage will generally appear abnormal sound.
Whether the vacuum gauge, pressure gauge, ammeter reading is normal.
1. Vacuum gauge needle can not swing too large, too large may make the inlet of pump vaporization, in addition to the vacuum gauge reading can not be too high, too high may be the inlet valve clogging, jammed or suction pool level is reduced.
2. The outlet pressure gauge reading is too low, may be the sealing ring, guide vane sleeve serious damage. Stator and rotor clearance is too large, or the outlet valve is opened too large, the flow rate is large, the head is low.
3. Ammeter reading is too large,maybe the flow is large, or friction between the stator and rotor .
1. Vacuum gauge needle can not swing too large, too large may make the inlet of pump vaporization, in addition to the vacuum gauge reading can not be too high, too high may be the inlet valve clogging, jammed or suction pool level is reduced.
2. The outlet pressure gauge reading is too low, may be the sealing ring, guide vane sleeve serious damage. Stator and rotor clearance is too large, or the outlet valve is opened too large, the flow rate is large, the head is low.
3. Ammeter reading is too large,maybe the flow is large, or friction between the stator and rotor .
Whether the pump and motor have large vibrations.
1. The centerline of the shaft of the pump and the motor is not centered.
2. The foot bolt of the pump or the motor is loose, or the foundation is not secure.
3. The mass of the rotor is not balanced
4. The pump is running in small flow, which produces radial force, backflow, cavitation.
Whether the seal working is normal.
1. The seal will not drip during normal operation.
2. If there is a cooling water unit, check for proper water flow.
● Stop
The centrifugal pump should be stopped first by closing the outlet valve to prevent the backstop valve from failing, resulting in pressure water from the outlet pipe backing up into the pump, causing the impeller to reverse, resulting in damage to the pump.
If the inertia of the pump is small when it is stopped, the pump stops very soon after the power is cut off, it means that there is a friction or eccentricity phenomenon in the pump.
Centrifugal pump start, run, stop the three steps are very important, but the most important is the outlet valve adjustment.
If the suction state, the outlet valve opening can be relatively large, if the backflow state, the outlet valve opening can be relatively small. The outlet valve adjustment point closer to the design point of the pump the better, so that the actual flow state and the theoretical design close to coincide with the pump's high operating efficiency, saving resources. Because the pump's high efficiency point are near the design point, of course, ultimately to the current is not overloaded as a prerequisite.
When centrifugal pump start, the pump export pipeline is not water, so there is no pipeline resistance and lifting height resistance, after the pump start, the pump head is very low, the flow is very large, at this time the pump motor shaft power output is very large according to the pump performance curve, it is very easy to overload, it will make the pump motor and wiring damage, so start to shut down the export valve, in order to make the pump run normally.
