Factors to Consider When Designing a Volute Pump Body

Oct. 14, 2020


In the volute design, the most important design variable is the area of the throat. This area and the area of the impeller outlet determine the optimal operating point of the pump. The throat area can be determined according to the speed coefficient recommended in this tutorial. When considering the installation of different impellers with one pump body, the throat area should be initially determined according to the standard impeller, and then the throat area should be increased by 10% to ensure the efficiency of the pump under large flow conditions.

Because the conversion of kinetic energy to pressure energy occurs in the diffuser, special attention is paid to the design of the diffuser.

The designed OEM pump casing should ensure the same speed in all sections.

Use at most three arcs to smoothly connect the spiral line from the tongue to the throat.

Oem Pump Volute

Oem Pump Volute

Mechanical aspect

OEM Pump Volute, especially the double volute pump body, is difficult to cast. In small and medium-sized pumps, the volute area is small, the flow path is long, and a long suspended sand core is required. In a volute multi-stage pump, this problem is even more prominent because there are several complex sand cores in a pump body.

In order to minimize the hydraulic loss in the volute, the flow channel is as smooth as possible. Since cleaning the volute is difficult and time-consuming, the foundry should try every means to cast a smooth runner.

Foundries generally use special sand cores, ceramic cores, and other methods to cast smooth castings.

However, especially for multi-stage volute pumps, the flow parts, such as the surface of the volute around the impeller and the vicinity of the throat of the volute, should be manually polished to make up for the lack of casting.

In addition, the separating tongue should be sharp and the distance to the centerline of each stage of the impeller should be equal.

It is very common for the size of the volute pump body to be deviated due to uneven shrinkage or core movement, and uneven shrinkage will occur even if the same material is used and the same model is used.

Since uneven shrinkage or core movement is inevitable, there should be enough end face string for the rotor during design, and the string should not be less than 12mm.