Читать книгу Pump Wisdom - Robert X. Perez - Страница 16

The elementary process pumps illustrated in Figures 1.1 and 1.2 probably incorporate one of the radial vane impellers shown in Figure 1.5. If a certain differential pressure is to be achieved together with higher flows, such a pump is often designed with a double‐flow impeller (Figure 1.7). One of the side benefits of double‐flow impellers is very good axial thrust equalization (axial balance). A small thrust bearing will often suffice; it is shown here in the left bearing housing. Note that the two radial bearings are plain, or sleeve‐type. Certain sleeve bearings have relatively high speed capability.

Figure 1.7 Double‐flow impellers are used for higher flows and relatively equalized (balanced) axial thrust.

Source: Mitsubishi Heavy Industries, Ltd. [4].

If elevated pressures are needed, several impellers are lined up in series on the same pump rotor. Of course, this would then turn the pump into a multistage model Figure 1.8.