How to calculate and select a rotor pump based on piping layout, operating flow rate, and medium
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Recently, I worked on a pipeline for transporting xylose mother liquor. The temperature of the fluid in this pipeline was 40–50 degrees, its viscosity was 50 cp, the inner diameter of the pipe was DN25, the length of the straight sections was 160 meters, there were 40 elbows, and the elevation change along the pipeline was 15 meters. Since I didn’t have much knowledge about pumps, the pumps chosen initially were horizontal or vertical centrifugal pumps designed for handling clean water. When selecting these pumps, attention was mainly paid to flow rate and head, while the layout of the pipeline was not taken into consideration. During the selection process, a vertical centrifugal pump was initially chosen, but the pump manufacturer recommended a rotor pump. I specified the required flow rate; at that time, the piping layout was not taken into consideration. The pump model selected by the manufacturer from Dongzheng was TU-1/r-23, equipped with an inverter-driven motor. Its flow rate ranged from 1.5 to 4.5 cubic meters per minute, the pressure was 5 bar, the inlet and outlet pipe diameters were DN40, and the power consumption was 1.1 KW. However, during installation and operation, the maximum flow rate achievable was only 1.2 cubic meters per minute, which was far from sufficient to meet the requirements. Does anyone have any good methods for selecting and calculating that they could share?
The last edit to this post was made by 3983596_FPPZ on 2020-8-18 at 10:30. Rotary pump is suitable for transporting fluids of a certain viscosity; lower viscosity results in lower efficiency. It is necessary to ensure that the material flows into the pump continuously and without obstruction, and reliance on the pump’s suction force to draw in the fluid should be avoided as much as possible； Minimize the resistance caused by fittings such as elbows and valves at the outlet. Rotor pumps adjust flow rate by varying their rotational speed; start the pump by opening the valve, and never try to regulate the flow rate through the outlet valve, as this can easily cause the pipes to burst. Therefore, the outlet must remain unobstructed
The reason for the low flow rate is excessive resistance in the inlet and outlet pipelines; increasing the pipe diameter, reducing the flow velocity, and minimizing losses are solutions
Thank you for your answer. Is there any good method for selecting the appropriate model, or are there any recommended manufacturers of rotor pumps?
Pumps that have not been used should be used with caution. We purchased a batch of swing rotor pumps for unloading purposes. To ensure complete emptying, the manufacturer recommended swing rotor pumps, stating that they can handle a gas-liquid mixture range of 0 to 100 without any issues. In reality, it was replaced after just a few years of use.
A gear-pumped twin-screw pump could be considered, WX15068542311
In a standard twin-screw pump, there is a gap between the rotor and the wear-resistant bushing, which results in lower leakage resistance compared to those with sealing gaskets
This post was last edited by Zhongheng Pump Industry on 2020-8-19 at 13:43. Hello, friends! The main reasons are that your outlet pipeline is narrow, long, and has many bends; it also has to rise 15 meters in height. Additionally, with temperatures of 40-50 degrees and a viscosity of 50 cp, the viscosity is likely to be even higher at room temperature, which results in greater resistance. As a result, the flow rate can only reach 1.2 cubic meters per unit time. Without replacing the pump, the solutions are: 1. Provide heat tracing for the pipeline to reduce viscosity. 2. Bold the pipe diameter. My phone number: 13313170275 (same number on WeChat)