Progressive Cavity Pump

Progressive cavity pump,is a pump that transfers fluid through a sequence of small, fixed shape cavities as an helix shaped rotor is rotated. The rotor is formed as a single helix shape of some length. The stator or cylinder is formed as a double-helix having twice (2X) the pitch of the rotor. As the helix shaped rotor rotates within the stator, the fluid is compressed and displaced along the length of the pump. Typically, the rotor is made from a rigid metal and the stator or cylinder is fabricated from an elastomer or elastomer coated cylinder. The rotor and stator are designed with a known interference fit which ultimately creates the series of sealed chambers called cavities. These pumps are commonly used as metering pumps due to their constant flow attributes when pumping of viscous or shear sensitive materials. The geometry of the rotor and stator was difficult to understand as I tried to follow the explanation of the form in the original patents. I think I got it right as witnessed by the single contact line between rotor and stator.