How to start a sewage tank lift pump.
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Dear colleagues in the field of processes and equipment, our facility is equipped with a set of sewage lift pumps as shown in the diagram. This is the first time these pumps are being started, and they will not start no matter what we try. Could you please advise us on how to operate such pumps during their first startup, as well as how to maintain them going forward? Thank you all.
1. The pipeline configuration shall be installed in accordance with Greit’s technical requirements； 2. Use of heat tracing in winter ； 3. Fill the blue water tank with clean water (desalinated water is preferred), filling it to 2/3 of its capacity; 4. Follow the operating procedures for the centrifugal pump
Hello, teacher. After filling it up, we started the process using the centrifugal pump; the outlet pressure could reach 10 kilograms without opening the outlet valve. When the outlet valve was opened by 2 turns, the pressure dropped to 6 kilograms. After 2 hours, the pressure fell to 1 kilogram. The liquid level in the sewage tank decreased from 93.86 to 93.59. The tank contains production wastewater, so it’s not a problem related to the composition of the water. The pump still doesn’t perform well, and we’re not sure what the issue is.
Hello, teacher. After filling it up, we started the process using the centrifugal pump; the outlet pressure could reach 10 kilograms without opening the outlet valve. When the outlet valve was opened by 2 turns, the pressure dropped to 6 kilograms. After 2 hours, the pressure fell to 1 kilogram. The liquid level in the sewage tank decreased from 93.86 to 93.59. The tank contains production wastewater, so it’s not a problem related to the composition of the water. The pump still doesn’t perform well, and we’re not sure what the issue is.
Check whether a bottom valve is installed on the inlet pipeline; inspect the inlet pipeline and the blue tank (self-priming bucket) for leaks. If there are leaks, air will gradually be drawn in. After starting the pump, air needs to be vented from the outlet pipeline
This post was last edited by CHANGBAISHI on 2020-2-12 08:33. Your question relates to operational control. Try it in my way: once the pump starts and the pressure reaches its maximum value, which is the pump’s head (slightly higher pressure), the outlet valve should be opened gradually, but it is essential to maintain the pressure at the pump’s outlet. Remember, the opening degree of the outlet valve should not be used as a criterion. Until the system pressure gradually rises to the design pressure, you can refer to the motor’s rated current to appropriately open the outlet valve and adjust the flow rate. This rated current serves as the reference point for controlling the pump flow rate; it cannot be too high, as otherwise the flow rate will be insufficient. The pump pressure also needs to be maintained. It’s not possible when the pressure is low. Oh, the pipe must be filled with water, with the outlet valve fully closed and the inlet valve fully open before the pump can be started. It’s worth giving it a try. To add, the problem at present is that the system has no water, so it cannot generate pressure. Gas is generated in the impeller, which prevents it from doing work on the water. Opening the outlet valve is to ensure the proper operating conditions of the pump. As the system gradually fills with water, a certain pressure is generated, and you can then increase the water supply amount step by step until the desired level is reached. At this time, it is adjusted to the optimal level using the current as a reference.
The current should not be too low; it is advisable to keep it above half of the rated current. If the outlet is too small, it can cause problems with the pump, and over time this may lead to a loss of pressure, manifested as reduced outlet pressure and unstable pressure levels.