Removing solids from a fluid

A method for removing solid particles from a particle containing stream of fluid, the method comprising the steps of:

• inducing the stream to flow at supersonic velocity through a conduit;
• inducing a swirling motion to the supersonic stream of fluid thereby causing the particles to flow to a radially outer section of a collecting zone in the stream;
• creating a shock wave in the stream so as to decrease the axial velocity of the fluid to subsonic velocity:
• and
• extracting the solid particles into an outlet stream from the radially outer section of the collecting zone wherein extraction the particles into an outlet stream from the radially outer section of the collecting zone is downstream of the shock wave and downstream the location where the swirling motion is imparted.