Abstract: A device for detecting an interface between two fluids of differing electrical properties, said device having an electrical circuit comprising transmitting means for transmitting electrical impulses to said fluids, a detector of electrical impulses, and at least one probe which is adapted to extend into said fluids; said probe comprising an electrically conductive probe member and a grounded electrically conductive shield, the probe member being mounted within the shield and being spaced from the latter by an air core, the probe member adjacent its distal end portion, being sealed to the shield by a dielectric seal which prevents the ingress of said fluid into the space between the shield and the probe member.

Abstract: A method of separating the components of a non-Newtonian fluid. Movement of the fluid is effected, the non-linearity of the shear stress/shear rate property of at least one component of the fluid is utilized to separate the fluid components, and at least one of the separated components is passed to a point of use through a passage which does not vary as a result of the movement of the fluid.