Trial operation plan for shielded pump

The poster can look for it from several aspects: 1. The product manual of the shielded pump used, which usually provides detailed instructions； 2. The technical personnel from the manufacturers of shielded pumps generally possess unique insights and extensive experience ； 3. Searching online, such as on Baidu, usually provides a wider range of information. For reference only.

I completely agree with what was said above; sometimes it’s better to have the manufacturer or technician come to the site for guidance, rather than relying on written instructions

There are also many different types of shielded pumps, and the commissioning procedures vary slightly depending on the type. These details can be obtained from the suppliers. Shanghai Nikkiso and Dalian Empire are both good suppliers.

The machines produced by Nikkiso are of poor quality; the best shielded pumps are those made by Hamilton. Domestic shielded pumps also have good quality and can meet the requirements under normal operating conditions. We find Dalian Huanyou to be quite good. Shielded pumps cannot be rotated manually, so it is best to disassemble and clean them before the trial run to ensure the cleanliness of the pump chamber. While driving, click to check whether the pointer is moving forward or backward; if it is moving backward, inform the electrician immediately to make the change. The rest are similar to ordinary chemical process centrifugal pumps.

Safety Operating Procedures for Shielded Pumps I. Checks before startup: 1. The insulation resistance must be above 2 MΩ. 2. Check whether the rotation direction of the motor is consistent with the direction of the arrow on the pump casing. (Only applicable in case of a problem with the original ignition system or electrical wiring; not required for normal operation.) 3. Check whether the bearing monitor is pointing to the specified area; if the pointer is in the red indicator zone, it indicates an abnormality. II. Pump startup: 1. Fully open the inlet valve and slightly open the bypass valve to remove air from inside the pump. At the same time, the reverse circulation valve is opened fully to fill the pipeline with liquid. 2. Start the pump, open the bypass valve, and fully discharge the gas from within the pump. 3. After exhaust is complete, gradually close the bypass valve, check whether the outlet pressure gauge shows the specified pressure, and then slowly open the outlet valve to bring the discharge volume to the flow rate at the operating point. 4. Adjust the valve of the reverse circulation tube to keep the reverse circulation rate within the range of 8–15 l/min, while simultaneously checking whether the liquid is flowing adequately inside the glass sight glass. 5. During operation, pay attention to the pressure difference before and after the coarse filter; if this difference increases significantly, it is necessary to reverse the pump’s direction of operation.

Precautions for the safe operation of shielded pumps: 1. During normal operation, the outlet valve must not be closed completely; it should remain slightly open to prevent air blockage inside the pump. 2. Operation without liquid or operation with a flow interruption of more than 1 minute is strictly prohibited to prevent damage to the motor and bearings. 3. Reverse operation is strictly prohibited for more than 1 minute, as it may cause abnormal wear of the bearings. 4. Operation under cavitation conditions is strictly prohibited; running the pump in such conditions will lead to premature wear of the bearings. 5. When shutting down the pump, first open the bypass valve, then close the pump outlet valve, press the shutdown button, and close the reverse circulation valve.

I. Operation Steps A. Start the pump 1. Check whether all fastening components are secure, whether the pressure gauge and cooling water are functioning properly, and whether the outlet valve and the pump’s exhaust valve are closed with no leaks； 2. Slowly open the inlet valve, and check for any leaks; if any are found, contact someone to address them ； 3. Open the exhaust valve and the two exhaust valves on the pump itself, and slowly release the gas, being careful to avoid burns. Repeat this process several times until it is confirmed that no gas remains in the system ； 4. Connect the power supply, and observe the pressure gauge on the discharge side as well as the TRG indication; if the direction is incorrect, seek assistance before proceeding further ； 5. When the pressure and operating conditions are normal, slowly open the valve on the discharge side until the specified pressure value is reached ； 6. Check again the pressure gauge reading, the TRG indication, the operating noise and vibration for any abnormalities, as well as the condition of the cooling water. B. Stopting or switching the pump: 1. Start the standby pump following the startup procedure, then slowly close the outlet valve. Meanwhile, monitor the operation of the standby pump to ensure there are no abnormalities, and finally close the outlet valve completely. 2. Press the stop button to shut down the pump ； 3. Close the outlet valve ； 4. Stop the cooling water. II. Daily Maintenance 1. Regularly check the flow of cooling water to ensure that the surface temperature of the pump does not exceed the specified value; at the same time, pay attention to conserving water ； 2. Regularly check the TRG indicator; take prompt action if any abnormalities occur ； 3. Check the pressure indication and the condition of the inlet filter; clean it if necessary ； 4. Check for abnormal conditions such as operating noises, vibrations, and leaks, and address them ； 5. Adjust the outlet valve to ensure it does not operate under overload conditions ； 6. For the troubleshooting of shielded pumps, refer to the TRG instructions as well as the information on the faults of shielded pumps, their causes, and solutions ； 7. When the pump is not in use for an extended period, its cooling water and the medium inside it should be thoroughly flushed to prevent corrosion and freezing damage.

This post was last edited by yfq4308 on 2009-5-23 at 13:30. The instruction manual for the Sifang shielding pump is quite simple; the commissioning process should differ from normal operation. Thank you all for your answers.

5.2 Operating Procedures for Shielded Pumps 5.2.1 Checks to be performed before starting the pump ⑴ Whether the thermometers and pressure gauges are functioning properly. ⑵ Turn on the cooling water and check whether the floor drain is unobstructed. ⑶ Are the inlet and outlet valves fully closed? ⑷ Check whether the foundation bolts and connection bolts in all areas are complete and not loose. ⑸ Contact the electrical power supply department. 5.2.2 Pump startup steps ⑴ To ensure proper operation of the Hydramatic pump, it is necessary to fully fill it and remove any air from it. Fully opening the valves in the pump inlet and return pipelines, as well as the outlet pipeline, will enable automatic venting of the Hydrac pump. For CNK-type pumps P202A/B, it is necessary to open the vent valve located above the heat exchanger in order to release air. When transporting liquids that are prone to vaporization, the venting process must be repeated several times until the pump is filled with liquid. After venting, the outlet valve and the vent valve should be closed. ⑵ When starting the motor to check the pump’s rotation direction, it must be the same as the direction indicated on it; this can be determined by observing the pump’s outlet pressure while starting the pump. When the pump runs in reverse, the outlet pressure is much lower than when it is operating normally. ⑶ Slowly open the outlet valve to adjust the pressure. ⑷ Check the pump’s operation; only after the current, voltage, vibration, and other parameters are within normal ranges can you leave. During the initial phase of pump operation, increased monitoring is required, once every half hour, with regular inspections to be carried out after two hours. 5.2.3 Pump shutdown steps: ⑴ First, close the outlet valve. ⑵ Stop the motor. ⑶ Close the inlet valve. ⑷ Stop the cooling water. 5.2.4 Inspection items for the normal operation of shielded pumps ⑴ Outlet pressure. ⑵ Check whether the connection bolts in various parts are loose. ⑶ Operating temperature, noise, and vibration of the pump. ⑷ Cooling water status (if any). 5.2.5 Method for switching shielded pumps ⑴ The inspection items before starting the pump and the method of starting the pump are referred to 5.2.1 and 5.2.2. ⑵ Note: After starting the standby pump, gradually close the outlet valve of the operating pump while opening the outlet valve of the standby pump. ⑶ Once the standby pump reaches the specified flow rate and pressure, close the outlet valve of the operating pump, shut down the motor of the operating pump; for shutting down the pump, refer to 5.2.3. ⑷ During the initial stage of pump startup, inspections should be intensified, with checks conducted every half hour; after 2 hours, inspections can be carried out at regular intervals. 5.2.6 Common faults of shielded pumps and their solutions ⑴ Damage to graphite bearings: Causes include cavitation, shaft play, and fragmentation of the graphite. Treatment: Switch the pump and replace the bearings. ⑵ The pump cannot start. Reason: The medium has crystallized or is viscous due to low temperature. Treatment: Switch the pump and increase the temperature of the pump body. ⑶ Pump overheating. Cause: cavitation or interruption of cooling water supply. Treatment: Identify the cause and eliminate cavitation ； Restore the cooling water. ⑷ Vibration or noise: Cause – cavitation or bearing wear. Treatment: Identify the cause and eliminate cavitation ； Switch the pump to replace the bearing. ⑸ Low outlet pressure: Causes include cavitation, damaged impeller, and blockages by impurities at the inlet. Treatment: Identify the cause and eliminate cavitation ； Switch the pump and replace the impeller or remove impurities.

Not to mention shielded pumps, the common principle for all centrifugal pumps is to keep the inlet valve fully open and the outlet valve closed, not slightly open! During operation, pay attention to exhaust to prevent cavitation. First, it is necessary to determine the operating medium, which is the most important factor; for example, in the case of a methanol pump, cooling water also needs to be supplied.

References: Testing plan for individual units of shielded pumps and magnetic pumps http://bbs.hcbbs.com/viewthread.php?tid=308717; Testing plan for pump units http://bbs.hcbbs.com/viewthread.php?tid=47639