A mixed-flow pump is a type of pump that falls between centrifugal pumps and axial-flow pumps. The specific speed of a mixed-flow pump is higher than that of a centrifugal pump and lower than that of an axial-flow pump, generally between 300-500 Its head is higher than that of an axial-flow pump, but its flow rate is smaller than that of an axial-flow pump and larger than that of a centrifugal pump. Let's take a look at some of the basic characteristics of mixed-flow pumps.

1. The shape and structure of a mixed-flow pump are between those of a centrifugal pump and an axial-flow pump. The pumping principle of a mixed-flow pump and the high-speed rotation of the impeller generate both the centrifugal force of a centrifugal pump and the thrust of an axial-flow pump. The mixed-flow pump pumps water through the combined action of these two forces.

2. The performance of a mixed-flow pump is also between that of a centrifugal pump and an axial-flow pump. Compared with centrifugal pumps, it has a lower head and a larger flow rate. Compared with axial-flow pumps, it has a higher head but a smaller flow rate. For China's vast territory and complex terrain, it provides another type of pump selection that suits local conditions.

3. The performance of a mixed-flow pump is represented by operating parameters such as flow rate, head, power, efficiency, and speed. At a certain speed, the flow rate is a variable, that is, if the flow rate of the pump is changed, the head, power, and efficiency of the pump will also change accordingly. The change law of this relationship is comprehensively drawn into several curves, which is the performance curve of the pump.

4. For high-head mixed-flow pumps, the relationship between flow rate and head, and flow rate and power, is close to that of centrifugal pumps. When using it, the valve can be closed to start. At this time, the power is small, and the power unit is safe. For low-head mixed-flow pumps, the change law of its performance parameters is close to that of axial-flow pumps. When using it, the valve should be opened instead of closed. At this time, the power is relatively small, and the motor is not easy to be burned out.

In summary, the specific speed of a mixed-flow pump is between that of a centrifugal pump and an axial-flow pump. Low specific speed mixed-flow pumps generally adopt a volute type, and their structure is similar to that of a volute centrifugal pump. High specific speed mixed-flow pumps should generally be made into guide vane type, and their structure is similar to that of an axial-flow pump. Like other types of pumps, mixed-flow pumps have horizontal and vertical shafts, and the impellers are closed and semi-open. The impeller of a low specific speed mixed-flow pump is generally enclosed by front and rear cover plates; the impeller of a high specific speed mixed-flow pump is generally semi-open. Generally speaking, the head of a mixed-flow pump is lower than that of a centrifugal pump and higher than that of an axial-flow pump. Its flow rate is greater than that of a centrifugal pump and less than that of an axial-flow pump. Compared with centrifugal pumps and axial-flow pumps, the difference of mixed-flow pumps lies in the inclined outlet edge of the impeller. When the water flows out of the impeller, it is subjected to centrifugal force and thrust, and the flow direction is inclined between the radial and axial directions, so it is also called a diagonal flow pump. Because the flow rate of a volute mixed-flow pump is greater than that of a centrifugal pump, the width of the impeller flow passage and the cross-sectional area of the volute are relatively large. Therefore, the horizontal volute mixed-flow pump adopts a suspended cantilever structure instead of a bracket cantilever structure to avoid increasing the overall size and weight of the pump.