Dual volute pump

Some pump manufacturers use a different taetie to expand the operating window of their products. This is why the dual ohite pump exists. The dual volute pump is designed to operate over a wide range of flows and heads. 

In the easting procedure of the dual volute pump, a second cutwater is designed 180° opposite the first cutwater and another volute channel added. This way, all areas e.xposed to velocity and pressure around the volute easing are equal. All forces around the volute are equalized or eaneelled (Figure 9-15). 

There is more information on this in Chapter 9. Dual volute casings tend to equalize the radial hydraulic forces around the pump impeller, thus expanding the operating window of the pump. The Ns is a guide in selecting the adequate volute design. 

The second cutwater and volute channel create an additional obstruction to the flow through this pump, and for that reason it robs some energy from the fluid. This will reduce the efficiency to a small degree, but the operational range of these pumps is quite broad as you can see in the graph. The dual volute design easing is an optional cost accessory with some pump companies, and offered standard with others. 

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