Pump flow issues
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The appropriate pump was selected based on the supplier’s samples. However, the inlet and outlet diameters of the water pump are much smaller than those of the system pipes. At this point, in order to ensure flow rate and flow velocity within the pipes, and also in line with the principle of reducing costs, should the inlet and outlet valves of the pump be determined based on the pump’s diameter or based on the dimensions of the system pipes? Please advise, thank you
Generally, the inlet and outlet dimensions of a pump are one or two sizes smaller than those of the inlet and outlet pipelines connected to it; therefore, reducer fittings are needed for connection. Moreover, the reducer is usually connected closest to the pump’s inlet and outlet; in other words, items such as temporary filters and valves are generally designed according to the pipe dimensions, rather than being chosen based on the pump’s inlet and outlet dimensions. After working on more projects, one will be able to see it from the process perspective. :)
Regarding water pumps alone, I think it is more economical to use valves with sizes matching those of the pump’s inlet and outlet, as long as the possible flow rates can be maintained
It is determined based on the allowable pressure loss in the pump outlet pipeline. If the requirements regarding pipeline pressure drop are not strict, it is advisable to install a smaller valve first and then expand the pipeline diameter from the perspective of reducing costs; if the requirements for pipeline pressure drop are more stringent, then the pipeline diameter should be expanded first before installing the valve
The diameter of the pipes connecting the pump’s inlet and outlet is generally determined based on the economic flow velocity. If the inlet and outlet valves of the pump are selected based on the pump’s diameter, the valves may be cost-effective, but the long-term operating costs will increase; a comparison of the pipe pressure drops under the two scenarios makes this quite clear.
I’m thinking of using small ones for imports and large ones for exports. The inlet valve is connected directly to the pump
Import and export pipelines and valves are selected based on their own technical requirements; it is not necessary for their diameters to match those of the pump outlets. The pump inlet and outlet are directly enlarged at the lower end to match the process pipe diameter.
It is rare for the pump’s inlet and outlet to be two sizes or more smaller than those of the inlet and outlet pipes; if this is the case, it is recommended to reconsider whether the size of the pump’s inlet pipe is appropriate.
In many cases, the valves and the process pipes have the same dimensions. In my opinion, however, the valves should have the same size as the pump outlet; smaller valves are more economical and convenient to use, and the reduction in diameter after the valve does not result in as much loss as when using a larger valve with a reduction in diameter before it. The pump outlet already has a fixed throttling point, and if the valve has the same size as the pump outlet, it prevents additional throttling.
It depends; I’ve encountered every kind of situation
Generally, valves are chosen to have the same diameter as the system pipes, which helps to reduce resistance
Generally, the diameter of the inlet pipe of a pump is larger than that of the outlet; for example, the inlet is 8 inches while the outlet is 6 inches
Thank you all for your help. I consulted an expert, and I think his advice is good: the pump outlet should have reducing nozzles, which can reduce the flow velocity at the pump outlet. If reducer fittings are not used, the resistance in the pipeline increases; in severe cases, this leads to an increase in pressure at the pump outlet and a decrease in flow rate, failing to meet the pump’s performance requirements. Furthermore, this is also the reason why many pumps can save energy: as the flow rate decreases, power consumption drops as well, but it is not true energy savings. I’m not sure if this is the correct way to understand it Please give me some advice.
The pump outlet should have reducing nozzles, which allow for the adjustment of the outlet pressure and flow rate. If no size heads are used, the adjustment range becomes smaller; this can also result in higher resistance and greater energy consumption