In micro water pumps and micro self priming pumps, it is often referred to as "open flow", also known as "open flow". Generally, it refers to water pumps, liquid pumps, especially micro water pumps and micro liquid pumps that have no pressure at the outlet (i.e. are not subject to valves), nozzles, thinner pipes, etc

When there is no need for the pump to output the corresponding pressure to overcome the resistance under the condition of load resistance, i.e. "open" or "open", the pump can provide a maximum flow rate.

Once there is an added load, the flow rate of the pump will decay and cannot reach the maximum flow rate. However, the corresponding output pressure of the pump will also increase, and then meet the needs of spray, pressurization, car washing, water circulation, water transfer, improvement, scouring and other purposes. Widely used in fields such as laboratories. A typical water pump has a flow and pressure curve (also known as a flow head curve or Q-H curve). The two exhibit a similar inverse proportional relationship.

For example, the nominal "opening flow rate" of a micro water pump is 12L/min, and the maximum output pressure is 2.4 kilograms. The meaning is: When there is no pressure at the pump outlet, the flow rate can reach its maximum; 12 liters/minute (such as when unloaded), rather than representing it at high output