A high pressure pump (intensifier) generates high pressure water at 60,000 psi, which is then transitioned into high velocity water as it flows through an orifice (made from ruby. sapphire or diamond) into the cutting head (Figure I: Abrasive Cutting Head). However, even at this high pressure and velocity, the water alone cannot cut hard materials and garnet particles are introduced into the water stream to produce the necessary cutting force. In the mixing chamber (Figure 2 : Mixing Chamber), the high velocity water stream - which travels at more than three times the speed of sound — creates a Venturi effect that pulls the garnet particles into the water stream from a separate abrasive line. The rubbing action between the outer wall of the water stream and inner wall of the mixing tube accelerates the garnet particles from zero to one fifth of the water stream velocity. The garnet particles are not able to penetrate the water stream due to shear force but are entrained along the outerwall of the water stream.
The high velocity garnet particles are essential in the cutting process while the primary function of the high pressure water is to accelerate the garnet particles to the maximum possible velocity. This generates the energy to cut a variety of hard materials.