If the pump outlet is reduced in size, what will be the consequences?

If the pump outlet is reduced in size, what will be the consequences?  

Among the customers of Anhui Shengshi Datang, the purchase of chemical centrifugal pumps and metal magnetic drive pumps is quite common. However, some clients frequently provide incorrect specifications. When it comes to on-site installation, they discover the discrepancies and assume that minor adjustments will make the pumps usable—but this is not the case.

If a 1-inch pump outlet is fitted with an adapter to reduce it to 8 points (a smaller diameter), will this have any impact on the pump? Can reducing the outlet size achieve a throttling effect? Will increasing the outlet size result in higher head pressure?  

First, it’s important to understand one key point: every pump has its fixed performance parameters. Whether the pump outlet is enlarged or reduced, the head pressure will neither increase nor decrease.  

When the pump outlet is reduced in size, the outlet pressure will increase, but the pump’s parameters remain unchanged. If the pump outlet is enlarged, the pump can only operate up to its maximum parameter limits. Changing the outlet size is a manual adjustment and does not alter the pump’s inherent performance.  

Now, let’s discuss the potential impacts of reducing the pump outlet size:  

01 Reducing the pump outlet size is equivalent to partially closing the outlet valve. This increases the pump pressure and reduces the flow rate. The current draw of the pump may decrease slightly, but if the pump experiences vibration, the vibration will not diminish—it might even worsen.  

02 Reducing the outlet size does not change the pump’s head pressure. However, if external conditions change, it may affect the pump’s overall performance, potentially leading to higher outlet pressure. This change is dynamic, meaning that reducing the outlet size can act as a throttle, increasing the outlet pressure.  

03 If the operating conditions are not ideal, reducing the outlet size may shorten the pump’s service life. But if the pump operates normally after the adjustment, there is no need for concern.  

04 As long as the reduction in outlet size is not excessive, it should not cause major issues. However, if the reduction is too significant, it may impede water flow, increasing pressure on the pump and overloading the motor.  

05 Changes in the pump outlet size directly affect the flow rate, as industry professionals know. A larger outlet increases the flow rate, while a smaller outlet decreases it.

When adjusting the size of the pump outlet, it is important to consider the performance curve of the pump, the reduction of system resistance and dynamic flow rate, which leads to the diameter of the fluid velocity distribution, resulting in higher resistance and losses, and may change the operating point curve of the pump. Due to the potential throttling effect, the pump's head or maximum efficiency point will not change.

For chemical pumps and metal magnetic device pumps, improper filtration may result in frequency, vibration, or overheating, especially in high viscosity or corrosive fluid applications. In order to maximize performance, it always maintains consistency with hydraulic calculations, pump socket dimensions, pipe diameters, and system requirements.

We, Anhui Shengshi Datang, are willing to communicate and exchange professional technology related to pumps with everyone. Welcome everyone to discuss, and feel free to ask any questions about selection.