The mixing process of the static mixer is unlike any other mixing device.

The design of the mixer system is:-

Exact

Repeatable

Accurately predictable

Eliminates scale up problems

They lend themselves to continuous processing and in-line process control.

The device consists of a series of alternating right and left-hand helical elements of 180⁰ rotation, each juxtaposed at 90⁰ to the element preceding it.

Hence the mixing progresses as an unalterable function of geometry.

The mixing action takes place on four levels:-

a)    Flow divisions. 

• As the flow profile contacts the leading edge of each helical element, it is caused to split into two and forced to follow the geometric path created by the element shape.
• At the following element the two flows are split into two again, thus creating a geometric progression of flow division
• This progression proceeds according to the formula S=2ⁿ, where S is the number of strata produced and n is the number of elements e.g.
• • 12 elements produce            4096 divisions
  • 18 elements produce        262144 divisions
  • 24 elements produce  16,177,216 divisions

 b) Flow reversal

The opposite pitch rotation (right and Left-hand helixes) of successive elements causes the bulk flow to reverse rotational direction at each element junction.

 c) Radial mixing 

This is function of flow inversion and flow reversal within each mixer element.

The flow inversion occurs when the high velocity component of the stream located at the centre of each half-section contacts the leading edge of an element. Under these conditions the leading vectors of the stream shift, creating  a new series of velocity vectors and forcing the material from the centre outward to the inner wall of the irradiation chamber.

It is observed that the fluid rotation in a given element is opposite to the rotation of that element. For example, in a clockwise element, the half sections of fluid within that element are found to rotate counterclockwise.

The overall effect of radial mixing causes the stream to be continuously and completely dispersed and homogenised radially.

Viruses entering at the centre of the stream are forced to the inner wall and vice versa.

d) Axial differentiation.

Due to the continuous flow divisions, flow reversal and flow inversion at every element, axial flow profiles cannot get established and axial flow differentiation is kept to a minimum.  The mixer elements destroy the natural laminar parabolic flow profile of viscous liquids.