Particle separation and concentration using spiral inertial filtration

A fluid processing apparatus configured for separating particles from a fluid flowing through the apparatus, the apparatus comprising:

• a fluid inlet configured to receive a fluid containing particles;
• a main fluid channel extending from said fluid inlet and arranged in a spiral configuration and configured to cause differential migration of particles within the fluid flowing through said main fluid channel into unique equilibrium positions within said main channel according to a size of the particle thereby forming one or more particle streams and a particle-free region within the fluid flowing through said main channel;
• one or more outlets in fluid communication with said main fluid channel and configured to receive the particles from the one or more particle streams flowing from said main fluid channel;
• and
• one or more secondary channels extending from said main fluid channel along a length of said main fluid channel between the fluid inlet and the one or more outlets and configured to draw at least a portion of the fluid from the particle-free region within said main channel to increase the concentration of particles within the remaining fluid flowing through said main channel, wherein the main channel has a non-uniform geometry, wherein the geometry of the main channel is changed following a secondary channel to compensate for fluid removal via the secondary channel.