Radial thrust balance double volutes

In large volute casing pumps, a double volute is used instead of a single volute to compensate the radial thrust loads. Normaly, these casings are two partial volutes offset by 180 degrees with the same effect, which end in a common discharge nozzle. The efficiencies achieved are almost identical compared to a single volute. The use therefore brings no disadvantages in terms of efficiency, but the radial thrusts can be minimized to only 10 to 20% of the values achieved with single volutes.?Minimizing the radial load on the bearings over the full performance curve will have a significant impact on the lifetime of a pump. This is particulary importent if we take about a mag driven pump. However, the double volutes place very high demands into the casting technique, as they have a core that has to be removed after casting.?It's pretty easy to identify them by looking down the discharge flange. A noticeable vane is located inside the nozzle that divides the inner diameter of the discharge nozzle.