Patent ID: 7442019

Claim:
A Moineau stator, comprising: a tube ( 10 ) having lobes ( 3 ) arranged in a configuration which is adapted to interact with a rotor, the tube ( 10 ) is thin-walled with walls ( 2 ) that are sufficiently thin as to be subjected to elastic deformation in response to interfacial seal forces imposed by interference with the rotor and is surrounded by a supporting structure ( 201 ) in the form of a support housing having walls able to resist pressure, torque, and axial loads experienced in its intended operating environment, discrete pressurized axial cavities ( 203 ) are positioned in an annulus ( 202 ) between the tube ( 10 ) and the support housing ( 201 ) and fluid passages ( 206 ) are provided to equalize pressure in the axial cavities ( 203 ) with pressure within the interior ( 5 ) of the tube ( 10 ) by allowing fluids from the interior ( 5 ) of the tube ( 10 ) to communicate with the axial cavities ( 203 ).