**2.6 Diagram of state for hydraulic conveying systems**

A diagram of state, similar to **Figure 2**, can now be drawn for hydraulic systems, to include high concentration transport, and is shown in **Figure 7**.

The similarities between **Figures 2** and **7** are strong, showing very similar characteristics for dilute or conventional hydraulic conveying, as well as low velocity high concentration flow. In this case, though, rather than the unstable region being simply a function of conveying velocity, it is now a function of solids' concentration being problematic at the intermediary concentrations.

Before leaving this section on Newtonian systems a brief description of the RRSP will be given, although it is noted that other solids feeders can also be successfully employed, e.g. the Kamyr feeder or similar, and various lock hopper systems (e.g. [13]).
