Technical | Zonal Density Gradient Reorientation

Gradient materials are loaded while the rotor is at rest, the flow is stopped and a linear density gradient is formed while the rotor is accelerating to a set speed.  Following a reorientation phase the gradient transitions from horizontal to vertical in the rotor.  After this transition occurs then the rotor can be accelerated to set speed while in a continuous flow operation.

Zonaldensity gradient reorientation


Step Process
1 The density gradient is loaded into the rotor while it is at rest.
2 As the motor is gradually accelerated, the gradient reorients itself vertically along the outer wall of the rotor assembly.
3 Once at operating speed, sample fluid is pumped into the rotor on a continuous flow basis.
4 The sample particles sediment radially into the gradient of increasing density.  They eventually band (iso-pycnically) in cylindrical zones where the gradient density equals a particle's buoyant density.
5 At the end of the run, the rotor is decelerated to rest.
6 The gradient reorients itself to the original position without disturbing the particle bands.
7 The banded particles are now ready to be unloaded.  Fractions are collected using air or water pressure and a pump to control flow.