[Q&A Question 063] 2017.03.04
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This post was last edited by 955559 on 2017-7-21 22:23. [Q&A Question No. 063] What measures can be taken after a centrifugal pump becomes vacuumed out? 2017.03.04 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. Close the pump outlet valve and drain it within a specified time limit. 2. Reduce the speed. 3. Simultaneously reduce the outlet valve opening or lower the speed. 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 Round of Haichuan Outstanding Management Members Selection Contest http://bbs.hcbbs.com/thread-1655902-1-1.html (Source: Haichuan Chemical Industry Forum)
Shut down the pump immediately; once the liquid level rises, refill the pump and restart it
1. The higher the liquid level pressure at the inlet, the better. 2. The inlet flow velocity must not be too high; therefore, the pump should not operate at a discharge rate exceeding its rated value. If such an excess discharge occurs, it can be addressed by reducing the size of the outlet valve. 3. Where feasible, improve surface finish and reduce roughness, so that the shape, size, boundary thickness, and flow surface characteristics of the flow-through parts or main components of the hydraulic system help to minimize the occurrence of cavitation. 4. Reduce the incoming flow velocity; make the suction pipe as thick as possible. Do not specify an excessively high head value to prevent excessive actual flow rates. 5. Minimize the suction lift. The principle behind installing the suction pipe is to reduce suction resistance, and no suction valve should be used for flow regulation. 6. After cavitation occurs, the discharge valve can be reduced in size or even closed to eliminate noise and vibration, after which the cause can be investigated. 7. The installation height of the pump should not be too high; the higher the filling height, the better it is for preventing cavitation. 8. To prevent pipeline losses, the suction valve should be fully opened, and the filter screen should be cleaned regularly.
1. Close the pump outlet valve and drain it within a specified time. 2. Reduce the speed. 3. Simultaneously reduce the outlet valve opening or lower the speed.
1. Close the outlet valve slightly. 2. Reduce the speed. 3. Close the outlet valve slightly while reducing the speed
1. Close the outlet valve； 2. Open the pump outlet vent valve to release gas, then close the vent valve ； 3. Slowly open the outlet valve as the pressure at the pump outlet rises.
First, analyze the reasons for the vacuum condition and then take appropriate countermeasures. Generally, the following measures can be taken: close the small outlet valve, increase the inlet pressure head, lower the temperature of the inlet medium (by using water to cool the pump head); if nothing else works, switch to another treatment method
1. The higher the liquid level pressure at the inlet, the better. 2. The inlet flow velocity must not be too high; therefore, the pump should not operate at a discharge rate exceeding its rated value. If such an excess discharge occurs, it can be addressed by reducing the size of the outlet valve. 3. Where feasible, improve surface finish and reduce roughness, so that the shape, size, boundary thickness, and flow surface characteristics of the flow-through parts or main components of the hydraulic system help to minimize the occurrence of cavitation. 4. Reduce the incoming flow velocity; make the suction pipe as thick as possible. Do not specify an excessively high head value to prevent excessive actual flow rates. 5. Minimize the suction lift. The principle behind installing the suction pipe is to reduce suction resistance, and no suction valve should be used for flow regulation. 6. After cavitation occurs, the discharge valve can be reduced in size or even closed to eliminate noise and vibration, after which the cause can be investigated. 7. The installation height of the pump should not be too high; the higher the filling height, the better it is for preventing cavitation. 8. To prevent pipeline losses, the suction valve should be fully opened, and the filter screen should be cleaned regularly.
(1) Contact the relevant departments to address the liquid level issue; close the outlet valve to create pressure. (2) Check whether all purge steam valves are properly closed. (3) Contact the relevant teams to adjust the process conditions and inspect the process flow. (4) Contact the relevant teams to carry out inspections and repairs after making the switch. (5) Use water spray to cool the pump body. (6) Ensure proper exhaust for normal pump operation. (7) Monitor the inlet pressure, apply pressure, or switch the process flow. (8) Switch the pump and contact the maintenance team. (9) Open the inlet valve wider. (10) Switch the pump for maintenance. (11) Perform pump switching operations and contact the maintenance team
1. The higher the liquid level pressure at the inlet, the better. 2. The inlet flow velocity must not be too high; therefore, the pump should not operate at a discharge rate exceeding its rated value. If such an excess discharge occurs, it can be addressed by reducing the size of the outlet valve. 3. Where feasible, improve surface finish and reduce roughness, so that the shape, size, boundary thickness, and flow surface characteristics of the flow-through parts or main components of the hydraulic system help to minimize the occurrence of cavitation. 4. Reduce the incoming flow velocity; make the suction pipe as thick as possible. Do not specify an excessively high head value to prevent excessive actual flow rates. 5. Minimize the suction lift. The principle behind installing the suction pipe is to reduce suction resistance, and no suction valve should be used for flow regulation. 6. After cavitation occurs, the discharge valve can be reduced in size or even closed to eliminate noise and vibration, after which the cause can be investigated. 7. The installation height of the pump should not be too high; the higher the filling height, the better it is for preventing cavitation. 8. To prevent pipeline losses, the suction valve should be fully opened, and the filter screen should be cleaned regularly.
(1) Contact the relevant departments to address the liquid level issue; close the outlet valve to create pressure. (2) Check whether all purge steam valves are properly closed. (3) Contact the relevant teams to adjust the process conditions and inspect the process flow. (4) Contact the relevant teams to carry out inspections and repairs after making the switch. (5) Use water spray to cool the pump body. (6) Ensure proper exhaust for normal pump operation. (7) Monitor the inlet pressure, apply pressure, or switch the process flow. (8) Switch the pump and contact the maintenance team. (9) Open the inlet valve wider. (10) Switch the pump for maintenance. (11) Perform pump switching operations and contact the maintenance team