A. Principle of hydraulic conveyance

Contrary to the pneumatic conveyance (Section 155), the hydraulic conveyance of granular and powdered solid materials can also be used for very long distances because the carrier fluid is so incompressible. The applied physical principles are similar to those of the pneumatic conveyance. In this section only some special aspects, different from pneumatic conveyance, will be treated.

The most essential differences between pneumatic and hydraulic conveying systems are the aforementioned incompressibility and the density of the carrier fluid. Because of the high density of the carrier fluid, the flow forces required for the transportation of solids can be achieved at relatively low flow velocities. In addition, the buoyancy of the particles in the liquid partly balances the gravitational forces. The effect on the settling velocity of the particles is apparent from Figure 1 and Equation 155.6.

Figure 1 Free-fall velocity of a single particle in water (Weber, 1974)

B. Flow patterns