Tuthill offers the Heavy Duty (HD) Series for the most demanding applications – slurries, high viscosity products, suspended solids, concentrated acids, chemicals, high temperature liquids, sludge, resins, sewage and scum, paints, polymers, plastics, pharmaceuticals, foods, and shear sensitive fluids. Tuthill offers the Heavy Duty (HD) Series for the most demanding applications – slurries, high viscosity products, suspended solids, concentrated acids, chemicals, high temperature liquids, sludge, resins, sewage and scum, paints, polymers, plastics, pharmaceuticals, foods, and shear sensitive fluids. This rotary positive displacement, circumferential piston pump is Tuthill’s severe-duty problem solver. Heavy-duty construction provides longer life in the toughest pumping applications.