【Daily Question 2019】Hydrogen production and hydrogenation section – Question No. 023
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【Daily Question 2019】Hydrogen production and hydrogenation section – Question No. 023: What are the reasons why a centrifugal pump does not deliver flow after it is started? References: (1) The inlet tube bundle is not filled with liquid; (2) Gas is entrained in the liquid; (3) The liquid level in the container is too low; (4) The pump does not have sufficient effective net positive suction head. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Correct: 3 wealth, Incorrect: 1 wealth ； Mass posting of posts – rated based on the lowest score ； Replies that are unrelated to the answer are considered spam and will be deleted immediately. For management purposes, if you need to view content from a few days ago, please go to https://bbs.hcbbs.com/home.php?mod=space&uid=3862647&do=thread&view=me&from=space through the summary post below
⑴ The inlet tube bundle is not filled with liquid. (2) Gas is entrained in the liquid. (3) The liquid level in the container is too low. (4) The pump does not have sufficient effective net positive suction head.
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 pump is installed at too high a height; its installation height should be within the allowable range for the vacuum level at the pump’s suction side. 4. The water absorption pipes are too long and have too many elbows; the pipeline design is unreasonable. Design and arrange the pipes properly. 5. The rotation direction is incorrect; adjust the motor’s rotation direction. 6. The impeller seal ring and the pump body seal ring have worn out and corroded; therefore, they need to be replaced. 7. The packing seal is not functioning properly; tighten the packing.
1. No pump is used for pumping; it is evacuated； 2. The inlet pressure is too low, resulting in evacuation ； 3. Vaporization evacuation due to excessively high medium temperature ； 4. Lighter medium composition for evacuation ； 5. Equipment-related damages such as impeller cavitation and oversized mouth rings ； 6. Other reasons such as excessive outlet pressure, faulty display instruments, etc
(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.
1. The inlet filter is clogged. 2. The pump was not filled with fluid before starting, resulting in air in the pump’s inlet pipeline. 3. The impeller of the pump has come loose. 4. The valve disc of the pump’s inlet valve has come loose. 5. The valve disc of the pump’s outlet valve has come loose. 6. The pump’s outlet pipeline is clogged. 7. The pressure gauge at the pump’s outlet is not functioning properly. 8. The motor is rotating in the wrong direction
Insufficient rotation speed, air in the pump, incorrect rotation direction, etc
1. The inlet pipe is too narrow, resulting in insufficient suction； 2. The medium temperature is high, leading to severe vaporization and cavitation ； There are 3 inlet and outlet valves that are not open ； 4. The motor configuration is inappropriate, with insufficient power
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 pump is installed at too high a height; its installation height should be within the allowable range for the vacuum level at the pump’s suction side. 4. The water absorption pipes are too long and have too many elbows; the pipeline design is unreasonable. Design and arrange the pipes properly. 5. The rotation direction is incorrect; adjust the motor’s rotation direction. 6. The impeller seal ring and the pump body seal ring have worn out and corroded; therefore, they need to be replaced. 7. The packing seal is not functioning properly; tighten the packing.
⑴ The inlet tube bundle is not fully filled with liquid. (2) Gas is entrained in the liquid. (3) The liquid level in the container is too low. (4) The pump does not have sufficient effective net positive suction head
(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 runs in reverse. (5) The opening degree of the inlet line is too small.