【Q&A Question 062】2017.03.03
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This post was last edited by 955559 on 2017-7-21 22:24. [Q&A Question No. 062] March 3, 2017: What are the reasons why a centrifugal pump does not deliver flow after starting? The reference answers will be visible after responding; points are awarded by identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) 1. The inlet pipe is not filled with liquid. 2. Gas entrained in the liquid. 3. The liquid level in the container is too low. 4. The pump itself has an insufficient effective net positive suction head. 2017 Q&A Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657793-1-1.html 2017 Daily Question Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657794-1-1.html 2016 Q&A Summary Thread (updates completed) http://bbs.hcbbs.com/thread-1597792-1-1.html Third Phase of HaiChuan’s Outstanding Management Members Selection Contest http://bbs.hcbbs.com/thread-1655902-1-1.html (Source: HaiChuan Chemical Forum)
(1) Gas inside the pump causes vapor lock. (2) The impeller has fallen off, blocking the impeller; the wear gap of the impeller is large. (3) The liquid level is too low and it gets evacuated. (4) The pump rotates in reverse. (5) The opening degree of the inlet line is too small.
The liquid level in the tank is too low, and the liquid contains gas.
1. The resistance in the outlet pipeline is high; open the pump outlet valve appropriately to reach the operating point. 2. The impeller and pipes are blocked; clean the pipes and the flow channels of the impeller. 3. The installation height of the water pump is too high; it should be within the allowable range for the suction vacuum level of the pump. 4. The water absorption pipes are too long and have too many elbows; the pipeline design is unreasonable – the pipes should be designed and arranged properly. 5. The rotation direction is incorrect; adjust the motor’s rotation direction. 6. The impeller seal ring and the pump body seal ring need to be replaced due to wear and corrosion. 7. The packing seal is not functioning properly; tighten the packing.
(1) Gas inside the pump causes vapor lock. (2) The impeller has fallen off, blocking the impeller; the wear gap of the impeller is large. (3) The liquid level is too low, resulting in evacuation. (4) The pump rotates in reverse. (5) The opening degree of the inlet line is too small.
1. High resistance in the outlet pipeline, 2. Clogging of the impeller and pipelines, 3. The water pump is installed at too great a height, 4. The suction pipeline is too long with too many bends; the pipeline design is unreasonable, 5. Incorrect rotation direction, 6. Wear and corrosion of the impeller seal rings and the pump body seal rings, 7. Poor sealing performance of the packing seal device
Insufficient import traffic； Cavitation occurs in the pump ； Impeller damage
This post was last edited by zxsaqwe on 2017-3-3 09:04: 1. The inlet pipe is not filled with liquid. 2. Gas entrained in the liquid. 3. The liquid level in the container is too low. 4. The pump itself has an insufficient effective net positive suction head.
1. The water pump is not filled with water； 2. Gas entrained in the liquid ； 3. The liquid level in the container is too low ； 4. The pump itself has an insufficient effective net positive suction head.
(1) Gas in the pump causes vapor lock; (2) The impeller has fallen off, blocking it, or the impeller is worn with large gaps; (3) The liquid level is too low resulting in vacuum; (4) The pump is running in reverse; (5) The inlet valve opening is too small.
Air leakage, cavitation, inlet and outlet valves not opened, bottom valve blocked