The progressive cavity metering pumps feature a rotating unit made from "super tough" nylon. The material is virtually unbreakable, is more resistant to abrasion than stainless steel, and runs reliably at low speeds and under high pressure. Conventional progressive cavity pumps have a rotating unit consisting of ten individual parts. The patented MDP rotating unit is injection molded as a single piece, which is significantly less expensive than conventional units, easier to maintain, and much faster to replace. The new MDP provides pulse-free metering of low- to medium-viscosity fluids with repeatable accuracy up to ±1.0 percent. The pumps are available in four sizes with capacities from 0.1 to 580 l/h (2.5 gpm) and pressures to 12 bar (174 psi). They can be equipped with a specially designed electric motor with integrated frequency inverter and forced ventilation, or with mechanical variable speed drives. Speed can be controlled from 0 to 600 rpm by either a manual potentiometer or an external analog signal.These units are best suited for industrial wastewater, flocculants and other water-based chemical solutions, emulsions or slurries.