Cryogenic liquid pump failure causes and troubleshooting
1, the pump started, the export pressure rose â‘´ Impeller rotation direction does not match. ⑵ pump not fully to the cold, the pump gas. exclude: â‘´ motor input line two-phase wiring alignment ⑵ continue cooling, and open the anti-gas valve or adjust the seal gas pressure. 2, pump head or insufficient flow. â‘´ lack of motor speed. ⑵ impeller or pipeline blockage. ⑶ as the sealing pressure is too large, there is excessive gas into the pump. exclude: â‘´ increase speed. ⑵ cleaning. ⑶ adjust the seal gas pressure. 3, the liquid can not be absorbed, indicating strong pressure beat â‘´ pipeline valve is not open or pipe resistance. ⑵ pipeline leakage. exclude: â‘´ open or clean. ⑵ repair 4, the motor temperature rise. â‘´ motor problems. ⑵ impeller mouth ring has been rubbed. ⑶ labyrinth seal has rubbed. exclude: â‘´ electrician repair. ⑵ adjust the gap. ⑶ adjust the gap. 5, stop suddenly â‘´ seal gas pressure low chain. ⑵ stuck within the bearing. exclude: â‘´ adjust the pressure. ⑵ cleaning or replacement. 6, vibration or noise occurs â‘´ fuselage and rotor do not mind. ⑵ pump inlet pressure is too low or other causes of cavitation. ⑶ moving parts and fasteners friction â‘· rotor parts loose. exclude: â‘´ adjustment ⑵ adjust the pressure, deflated. ⑶ correction â‘· maintenance Several liquid pump accident analysis (1) put into operation for the first time to adjust the argon gas, open West No. argon pump, the outlet pressure how to get on, not enough to use full, cold, the highest frequency control, filter inspection, insulation wall import and export inspection, treatment methods There is no effect, manufacturers on-site commissioning staff also helpless. Turn on the East No. argon pump, the pressure quickly up and running normally. After the inspection Pa Pa and found that the West imported argon pipeline design is unreasonable, too many elbows, had a crude argon tower reactor Tata low, so that argon pump inlet NPSH less than the design value, the pressure on the exit. On the import pipe reform, reduce elbow. Re-start, everything is normal. (2) argon pump outlet pipe at the top of the crack, stop overhaul, and then start and found that argon pump running shortly after the pressure fell off, heating backflush, and then start, the same is true of the whole tower liquid Tata â…¡ Net, re-fluid, argon pump still can not operate normally. Finally Pa Argon pump a small cold box, remove the import filter network, the problem can be solved. Analysis, â…¡ tower into the pearl sand because: argon pump outlet pipe at the top of the crack, stop, leak into the pearl sand, and then flow to the top of the crude argon â… tower, heating through the fractionation gas pipeline into the crude argon â…¡ tower . (3) Argon pump sealing gas pressure nitrogen began to be selected, and soon found the seal system mixture discharge pipe liquid discharge, the analysis that the sealing gas blockage, with a trace water analyzer to analyze the pressure of nitrogen and found that the water content of nearly 1000PPm, the water is due to the piston Nitrogen compressor cooling water is not tight leak into the steel sleeve, the problem can be found. Seal gas switch to the instrument air, the argon pump is operating normally. (4) For the first time, the process of abolishing refined argon column was adopted. The purity of trace nitrogen in semen argon has been unqualified. It is suspected that it is caused by leak of seal gas. The research decided that the seal gas should be changed to Argon pump outlet pressure argon. As a result, , Sealing gas has changed back to the instrument gas. Finally, the second phase of transformation, additional refined argon column, the sperm argon qualified. (5) In early August of this year, the East Turbine pump was found to have leaked overnight and switched to the West argon pump. At start-up, the speed could only be adjusted to 2900 rpm and the pump outlet pressure was about 0.58 MPa. Top of the tower. Electrical consulting manufacturers, re-commissioning drive, speed reached 3600 rev / min, pump outlet pressure rose to 0.8Mpa, liquid can be successfully into the top of â… tower. Liquid oxygen adsorption Used for liquid oxygen pump the sudden stop has little impact on the air separation system, it should be noted that the main safety, to take the risk of the main cold liquid oxygen impurity ground analysis, measures to strengthen the liquid oxygen emission. Some liquid pumping stops have a great influence on the air separation system. (1) Sudden stop of the circulating liquid argon pump in the hydrogen-free argon flow process, the crude argon condenser is still working, a large amount of liquefied liquid accumulates in the bottom of the crude argon column , Can not return to the crude argon â… tower to participate in distillation, and then back to the tower, so that the top of the crude argon column oxygen rapidly increased, the main cold liquid oxygen level dropped significantly, the main cold liquid oxygen level is too low Is not conducive to safety; the second is to reduce the heat transfer area, eat less air, oxygen production decreased, so that the main fluctuations in the working conditions. (2) Up and down the tower in the process of separation of circulating liquid oxygen pump sudden stop, a lot of liquid oxygen accumulated in the bottom of the tower, can not return to the main cold, will also make the main cold liquid oxygen level significantly reduced, the results above, may also occur Nitrogen plug. Therefore, the two processes, if the pump sudden stop, to quickly resume; normal inverted pump, but also be careful operation, to ensure stable and uninterrupted flow (hydrogen-free argon argon flow suddenly increased, will pollute the main cold oxygen, Oxygen purity drops, even nitrogen plug.). (3) for the process of internal compression pump sudden stop, will affect the supply of oxygen, nitrogen and argon products. The following liquid argon pump pump operation talk about how to experience: First of all, a reasonable circulation of argon pump process on the safe operation of the pump and smooth pump down is very important, the process shown in Figure 4 is more reasonable, each argon pump each have an independent inlet pipe to ensure that the cold, standby pump replacement does not affect the operation Pump; filter, compensator, check valve, safety valve set as described above; other argon pump outlet return pipe can not be too thin, or the whole backflow pump pressure is too high, not conducive to pump safety; heating valve To be installed in the pump, in order to ensure heating, the impurities on the filter can be removed clean. At present, the more advanced process is that two liquid pumps are prepared for one use and one spare, the standby pump is in a cold state and runs at a low speed. When the main pump fails to stop, the standby pump can immediately be put into normal operation and the operation of the entire set can be maintained. The correct operation of the pump is: pre-cooling pump to start, as described in the fifth "centrifugal liquid pump start" described, it should be noted that, because to be cold to consume about 98% argon argon , To the top of the crude argon column â… regulating valve will automatically shut down, the crude argon column â… reflux ratio is reduced, the crude argon purity deteriorates, trace oxygen rise, therefore, to the cold to reduce the crude argon output, in order to maintain the purity and stability. In addition, after the standby pump starts, stop the pump immediately, pay attention to ensure stable flow of crude argon â… tower, do not fluctuate greatly, otherwise it will affect the main tower conditions.
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