When the suction circumstances of the pumping applications are less than optimal is another excellent illustration of when to use a Progressing Cavity Pump. Because the internal pump velocity is lower, a progressive cavity pump requires significantly less Net Positive Suction Head (NPSH) than a centrifugal pump. While a centrifugal pump cannot operate with a suction pressure as low as 28" of mercury (Hg), a progressive cavity pump may. When a centrifugal pump cannot adequately fill or pump in a given application, a progressive cavity pump can.
Because of their lower internal velocities, progressive cavity pumps are perfect for applications where the liquid is shear sensitive once more. Pumping oil and water mixes to separation equipment is an excellent example. When the oil droplets are larger, the separating device performs significantly better. While a centrifugal pump will emulsify the oil and lower the size of the oil droplets, reducing the separator's separation performance, a Progressing Cavity Pump will not alter the oil droplets.
