Effects of high outlet flow rate in centrifugal pumps
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I saw a centrifugal pump with a rated flow rate of 12.5 m3/h, a head of 300 m, an efficiency of 40%, and a rotational speed of 2950 r/min； It is currently used to transport C4 at a rate of 18.5 m3/h; what effects will long-term operation have on the pump?
No impact. The effective power of the pump = flow rate * head * density * gravitational acceleration. The rated flow rate determined at the time of manufacture was calculated using water in experiments; with the effective power remaining unchanged, if the medium becomes butane whose density is approximately 600 kg/m3, then the rated flow rate of the pump for this medium should be 1000/600*12.5 = 20.8 m3. In other words, the current flow rate falls within the rated range.
The key is to see whether your pump motor is designed for use with water as the medium; if not, it won’t work, as it’s easy to experience overcurrent that can damage the motor. .
These two old pumps were originally used for transporting C4 media as well. There is now a technical renovation project, and in order to save costs, these pumps are being reused. It’s no longer possible to find out whether the original design was based on water as the working medium; we have no choice but to use them anyway.
However, it seems that ordinary centrifugal pumps are designed to use water as the medium. . It should be noted that shielded pumps are designed to use a specific medium.
As long as vibration, displacement, etc. are fine
That’s great. Just make sure it’s sealed properly so there are no leaks. It is best to use a double-seal or shielded pump for transporting liquefied gas
Compare the current to see if it has increased
The rated flow rate of the pump is a volumetric flow rate, and it remains the same whether pumping water or carbon tetrafluoride. With such a significant increase in traffic, Yang Cheng will drop considerably. It is necessary to clarify whether the motor should be selected based on water pumping requirements or carbon tetrafluoride handling requirements. If it was originally selected for water pumping, then there is no problem; but if it was chosen for carbon tetrafluoride handling, the motor will trip due to overcurrent.
As traffic increases, Yang Cheng will decrease. The motor will trip due to overcurrent or get damaged.
It should work; generally, the nameplate indicates the flow rate and head required for a water test. If the flow rate is converted to that of C4, it should be sufficient. There is a preference to make use of existing equipment in order to save resources, and if that’s not possible, two pumps can be used simultaneously; another pump can be added later if there are problems. This approach meets the current needs while also allowing the use of existing equipment. One thing that needs to be clarified is whether the head requirement will be met under the new operating conditions.