Heavy duty valves are designed for applications involving high pressures, temperatures, frequent cycling, vibration, or corrosive fluids. They have thicker walls and parts than standard valves.

Typical materials include stainless steel alloys, carbon steel, cast steel, bronze, nickel alloys, and cobalt-based alloys designed to handle extreme conditions.

End connections like flanges, butt welds, socket welds, threaded, and specialty couplings suit various piping systems. Rating and materials match the pipeline.

Heavy duty valves utilise solid PTFE, chloroprene rubber, viton, compressed asbestos fiber, and graphite packing along with gaskets made of spiral wound metal and kammprofile.

Manual actuation using handwheels, gears, and chainwheels. Automated actuation uses pneumatic, hydraulic, or electric actuators often with fail-safe functions.

Pressure ratings vary widely but often fall between 1500 psi to 4500 psi. However, some special metal seated valves are rated beyond 10,000 psi.

Testing involves shell, seat, and backseat leakage checks, seal validation, high pressure resistance, temperature cycling, vibration, and flow performance.

Certifications can include MSS SP-70 for valve testing, NACE MR0175 for corrosion resistance, and various plant specifications like Shell SPE or API standards.

Oil & gas, chemical processing, mining, power generation, steam systems, and other extreme pressure, temperature, or fluid conditions.

Routine inspection for leaks and smooth operation should occur regularly. Timing varies greatly depending on usage but 2-5 years is typical for overhaul of internals.