【Q&A No. 023】2018.01.23
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【Q&A No. 023】January 23, 2018: What are the reasons for insufficient head in centrifugal pumps? How to handle it? Reason: (1) Clogging of the inlet pipe or filter screen ； (2) Excessive gap in the mouth ring ； (3) The working wheel is damaged or blocked. Treatment: (1) Stop the pump and clean it ； (2) Replace the mouth ring ； (3) Clean and replace the working wheel. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Due to the limitations on the number of posts in the “One Question per Day” section, “One Image per Day” has been moved to the registered devices section; you can access it through the directory I posted. For management purposes, if you need to view content from a few days ago, please go through the summary post below. 2018 Chemical Engineering Technology Training – Daily Questions Collection: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=18889712018 Registered Equipment Section – Daily Images Collection: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888970
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(1) Identify and address the cause of the low motor speed; (2) Control the outlet valve to adjust the discharge volume to a reasonable range; (3) Remove blockages from the impeller flow channels; (4) Stop the pump, disassemble it, and check/adjust the clearances between various components inside the pump; (5) Replace the inter-stage seal rings; (6) Stop the pump and check the clearance of the balance disk; (7) Calibrate or replace the pressure gauge.
The pipe length and pipeline resistance were not taken into account during the design; the impeller of the centrifugal pump was replaced to ensure that the motor would not be overloaded, which allows the head pressure to be maintained but reduces the pump’s flow rate； To ensure both the flow rate and the required head, it is necessary to replace the pump with a new one ； However, the costs incurred in this way are high
What are the reasons for insufficient head in a centrifugal pump? How to handle it? Answer: (1) Clogged inlet pipe or filter screen ； (2) Excessive gap in the mouth ring ； (3) The working wheel is damaged or blocked. Treatment: (1) Stop the pump and clean it ； (2) Replace the mouth ring ； (3) Clean and replace the working wheel.
The impeller is severely corroded; replace it. The design is unreasonable; replace the pump. The rotation speed is insufficient; check the current
The prime mover or power source is not functioning properly. The solution is to check the power supply and the prime mover.
The liquid contains an excess of air or gas. Solution: Lower the liquid temperature to remove gas. The second reason for insufficient water pump head is too low rotation speed. Santian Pump Industry’s solution: Check whether the voltage is within the rated range, and check if the motor is operating properly
1. The feed rate does not meet the requirements; it is necessary to check whether the inlet pipeline is unobstructed, such as in the case of a clogged filter or insufficient valve opening； 2. The impellers are worn or defective, which requires repair of the pump ； 3 Unstable current prevents the motor from reaching the required speed
The impeller is installed in the wrong direction (double-suction impeller). The solution is to check the impeller. The liquid density and viscosity do not match the design conditions. The solution is to check the physical properties of the liquid. The flow rate is too high during operation. The solution is to reduce the traffic. The system’s static head increases. The solution is to check the liquid level and system pressure. The drag loss increases. The solution is to check for obstructions such as pipes and check valves. The wear of the casing and impeller wear rings is excessive. The solution is to replace or repair the wear ring and impeller. Leakage in other areas. The solution is to check areas such as the shaft seal. Clogging, wear, and corrosion of the pump impeller. The treatment methods are cleaning, inspection, and replacement.
This post was last edited by tczxs on 2018-1-23 09:30 (1) Impeller damage. Solution: Replace with another part. (2) Insufficient rotation speed. Treatment: Check the voltage and whether the motor is functioning properly. (3) The infusion contains gas. Treatment: Lower the liquid temperature to remove gas. (4) Import blockage. Treatment: Stop the pump and clean the inlet.
Reasons why the head of a centrifugal pump does not reach the rated value and solutions: 1. Clogging of the impeller – Over time, scale accumulation can block the flow channels in the impeller and pipes as a result of prolonged operation of the pump; it is necessary to conduct regular inspections, maintenance, and removal of such obstructions. 2· The motor speed is insufficient, the bearings are damaged, or the voltage is low; check the power supply and carry out timely maintenance or replace the damaged bearings. 3·Air entering the pump causes cavitation; empty the gas inside the pump promptly. 4• The water level has dropped, resulting in insufficient submersion depth and inadequate water supply ； Hydration should be replenished in a timely manner. 5. Severe wear of the mouth ring results in excessive clearance between the impeller and guide vanes, preventing the achievement of the designed flow rate and head under actual operating conditions ； Replace the impeller and mouth ring in a timely manner.