Progressive cavity pump stator

A progressive cavity pump comprises casing 1 containing stator 2 and metallic rotor 3. The stator has: metallic, inelastic inner part 2a contacting the rotor and outer transverse pressure generating part 2b between the inner part and casing. The outer part provides resilience forcing the inner part into contact with the rotor, whereas the inner part provides an erosion or degradation resistant stator surface or lining. The outer part may comprise: a polymer, a polymer/metal composite, improving heat conduction or, elastic or inelastic fluids. The fluid may be the pumped fluid supplied from pump downstream (Fig. 6) through an inner part aperture (12) or from an external source (Figs 7, 8). A manufacturing process is disclosed comprising: placing an inner part shaped mandrel in a metallic element within the casing, pressure shaping the inner part from the metallic element, removing the mandrel and applying the outer part.