High-pressure pumps for use in oil or gas well hydraulic fracturing operations; Valves being parts of machines; Axial flow pumps; Butterfly valves being parts of machines; Circulating pumps; Ball valves being parts of machines; Centrifugal pumps; Pneumatic valve actuators; Machine parts, namely, mechanical seals; Parts of oilfield wellhead machines, namely, gate valves, ball valves, check valves, plug valves, globe valves, choke and manifold industrial pumps, pump and valve parts, pipe fittin...