Heavy-duty valves have been designed to avoid corrosion problems in demanding conditions. The one-piece body, made of glass-filled polypropylene, provides mechanical and environmental strength. Due to the disc design, the valves have minimal pressure loss and turbulence in the line as well as low handling torque. The low operating torque is ensured by the full body linear seal whose main characteristic are its antifriction ring. The gasket can be supplied in food grade EPDM or Viton.