The principle of operation upon which the progressing cavity pump is based is deceptively simple. Available in either a 1:2 or 2:3 ratio configuration, Moyno progressing cavity pumps' key components are the rotor and stator. The rotor is an external helix precision machined from high-strength steel. The stator is an internal helix molded of tough, abrasion-resistant elastomer, permanently bonded within an alloy steel tube. The stator always has one more helix than the rotor to facilitate the progressing cavity pumping action. As the rotor turns within the stator, cavities are formed which progress from the suction to the discharge end of the pump, conveying the process fluid. The continuous seal line between the rotor and the stator helices keeps the fluid moving steadily at a fixed flow rate proportional to the pump's rotational speed.