Failure cause and troubleshooting, cryogenic liquid pumps:
Reason 1, the pump is activated, the outlet pressure rises on
â‘´ does not match the direction of rotation of the impeller. B pump not fully cooled, gas pump.
Exclude 1:
â‘´ two-phase motor input line switch wiring B cool and open the control valve or adjust the gas pressure.
Reason 2, pump head or flow insufficient.
â‘´ the motor speed is insufficient. B impeller blocked pipes. C due to the seal pressure is too large, there is too much air into the pump.
Excluding 2:
⑴ increases speed.       B cleaning. C adjust the gas pressure.
Reason 3, liquid not indicating pressure jumping
⑴ unopened pipeline valves or piping resistance. ⑵ pipeline leak.
Excluding 3:
â‘´ opening or cleaning. B repair
Reason 4, motor temperature rise.
⑴ motor problems. B impeller ring has been wiped. ⑶ Labyrinth has been rubbed.
Exclude 4:
⑴ electrical repairs.        B adjust the clearance. C adjust the clearance.
Reason 5, stopping suddenly
â‘´ chain of low gas pressure. B bearing jammed inside. Excluding 5:
â‘´ adjustment pressures. B cleaning or replacement.
Reason 6, vibration or noise
â‘´ the airframe and rotor misalignment. B pump inlet pressure is too low cavitation arising or for any other reason. C friction between moving parts and fixtures â‘· rotor parts loose.
Excluding 6:
B â‘´ adjustment adjustment pressures, outgassing. D c correction test
II, a few liquid pump accident analysis
(1) the improvement put into initial regulation AR, drive West, AR pump, outlet pressure on how not to, using full cold, frequency is the highest, check the filter screen, wall insulation inspection, import and export pipe process, there is no effect, manufacturer commissioning personnel are also at a loss. Drive East, argon pump, pressure very quickly, is operating normally. Overhaul after PA towers, discovery West of argon pump inlet pipework is not reasonable, too many elbows, crude argon Tata II Kettle run low, imports argon pump NPSH is not up to the design value, outlet pressure does not go on. Inlet pipe reconstruction, reducing elbows. Restart, all is well.
(2) for AR pump outlet tube cracked at the top, stopping after repair, restart, argon pump found to be running soon, pressure falls, after heated Jet, and then start, and still is, Tata cauldron II liquids drain back fluid, argon pump still does not run correctly. At last the grilled argon pump cold box, remove the inlet strainer screen, problem is solved. Analysts believe that the II entered the perlite in the tower because: argon pump outlet tube top craze, after parking, leakage of perlite, again flows to the crude argon â…° top, heating by distillate gas pipeline flowing into the crude argon II Tower. (3) the argon pump nitrogen gas began to use pressure, soon found that mixed gas discharge tube sealing system liquid discharge, analysts believe gas plug, using micro water pressure nitrogen Analyzer, found water near 1000PPm, which is due to nitrogen piston compressor cooling water leakage steel sleeve is not tight, cause to find the problem. Seal gas using instrument air, argon pump is operating normally.
(4) the first transformation, by cancellation of pure argon column flow, semen purity of trace nitrogen in argon have been unqualified, suspected to be caused by gas leakage study decided to seal gas switch to pump discharge pressure of argon argon, argon results semen still unqualified sealing gas reverted instrument air. Final phase II modification, the addition of pure argon column after semen argon qualified.
(5) in early August this year, running East ar pump found overnight, to switch to the argon pump starts, the speed can only moved to 2900 r/min, pump discharge pressure is about 0.58Mpa, liquid crude Argon is not playing I top. Electrician after consultation with the manufacturer, to refit the converter, speed up to 3600 r/min, pump discharge pressure up to 0.8Mpa, smooth scored first the top of the liquid.
Third, liquid pump suddenly stops the effects of air separation system
Liquid oxygen pumps for use in liquid oxygen adsorption of sudden stops have little effect on air separation systems, mainly to look for is safety, take main cooling liquid oxygen impurity analysis, enhanced liquid oxygen emissions, among other measures. Some liquid pump bursting stopped on empty points system effects is big, (1) no hydrogen business argon process in the of cycle rough liquid argon pump bursting stopped, rough argon condensation device still in work, liquefied of large liquid saved in rough argon II Tower bottom, cannot returned to rough argon ⅰ Tower participate in fine distillation, again returned to Shang Tower, such will makes rough argon ⅰ Tower Department containing oxygen quickly increased, main cold liquid oxygen liquid bit sharply reduced, main cold liquid oxygen liquid bit low a is not conducive to security; II is for hot area reduced, air eat not recently, oxygen production declined, makes main workers condition fluctuations is big. (2) the Tower up and down loop in a separate process in liquid oxygen pump suddenly stops, liquid oxygen and a lot of accumulated in the bottom of the Tower, go back to the main condenser will also cause the main cooling liquid oxygen level significantly lower results as above, and nitrogen can also occur. So for these two processes, the pump suddenly stopped, to quickly restore normal pumping, careful operation, ensuring a steady uninterrupted flow (hydrogen-free argon flow of liquid argon volume suddenly increases, it will pollute the main cooling liquid oxygen, oxygen purity down, even n. )。 (3) for internal compression process of liquid pump suddenly stopped, may affect the product the supply of oxygen, nitrogen and argon. Following experience of liquid argon pump pump operating on several points:
First reasonable of cycle argon pump process on pump of security run and the smooth pour pump is important, Figure 4 by shows process compared reasonable, each Taiwan argon pump each has a article independent of imports tube, to ensure to cold, and switching alternate pump Shi not effects run pump; filter device, and compensation device, and check back valve, and safety valve of set as Qian by said; addition argon pump export return pipeline cannot too fine, otherwise full return Shi pump of pressure high, not conducive to pump of security; heating valve to loaded in pump Hou, to guarantee heating Shi, can put filter device Shang of impurities blow except clean. An advanced process is, two pumps for liquids with a ready, low speed operation the backup pump is cold, when the primary pump failure after shutdown, standby pump running immediately, make the total device operation is not affected.
Right of pour pump operation is: on alternate pump for to cold, and started, as fifth items “centrifugal type liquid pump of started” by said for, must note of is, because to cold to consumption must of containing argon 98% around rough liquid argon, to rough argon â…° Tower Department Regulation valve will automatically shut small, rough argon â…° Tower of return than reduced, makes rough argon purity variable bad, trace oxygen rose, so, to cold Shi to corresponding reduced rough argon production, to keep purity stable. Spare pump starts after the stop running the pump immediately, being careful to ensure crude argon flow â…° Tower stable, do not fluctuate, otherwise it will affect the main tower operating mode. (From the Internet)
