Regarding the pump backflow issue

Whether the return fluid from these pumps can flow back to the inlet depends on whether the temperature meets the requirements of the inlet medium, as well as the pressure requirements. .

It should work. However, the centrifugal pump returns to the storage tank or inlet, usually for flow regulation. The two pumps you mentioned can directly adjust the flow rate, right?

Sure. In multi-cylinder piston pumps, there are many inlets and outlets; when overpressure occurs, the safety valve releases pressure back to the inlet, and for backflow regulation, it is possible to connect pipes to direct the flow back to the inlet as well

As mentioned on the 2nd floor, if the pump outlet temperature is high and then it returns, continuous heating may cause gas entrapment. However, diaphragm pumps and positive displacement pumps don’t seem to be affected by air entrainment

Yes, the positive displacement pump will release pressure to the pump inlet line through a safety valve. The centrifugal pump return line provides minimum flow protection.

With only one pump involved, and not a compressor, by how much will the temperature rise? Those who are concerned about overheating opt for water cooling. All issues encountered at present can be sent back to the input line, but the standard practice in design is to return all devices. Well, it might be to increase investment.

A diaphragm pump with a single pump head isn’t very suitable; suction and discharge don’t occur simultaneously, which already results in fluctuations in the outlet flow. If it is connected directly to the inlet, these fluctuations will be amplified

Give priority to the pump return inlet tank; the pump return inlet can also be used

There are two terms used to refer to the outlet pipeline of the centrifugal pump’s return line. The first one is the minimum flow line, which runs from the pump’s outlet to its inlet; it is through this line that air entrainment occurs when the pump operates for extended periods with the outlet valve closed. When a return line is available, it is best not to use this line for adjusting the pump’s flow rate, especially when dealing with liquefied hydrocarbons or light oils, as air entrainment is likely to occur in such cases. If the outlet valve of the device downstream of the pump is open, the flow rate downstream is low, and there is no return line, this line can be slightly opened to prevent pressure buildup in the pump; it is primarily used in situations where positive displacement pumps are used to transport heavy or viscous oils. The second type is what you mentioned, namely the return line, which is mainly used to protect pumps or for transferring liquids between tanks. For positive displacement pumps, it’s not necessarily the case that the fluid returns to the inlet; you must make a decision based on factors such as the pressure specified on the official website and the properties of the material.