Penn Valley has a truly unique approach to sludge pumping. The Penn Valley Double Disc Pump is a terrific solution for handling thick sludge, fluids with abrasive solids, grit or sand, or foamy air-entrained fluids. The pump can run dry without damage. And best of all, the pump has no mechanical seals or packing! The wear parts are very inexpensive when compared to other positive displacement pumps. See how this pump works at www.pennvalleypump.com.