M&J Valve Danflo is engineered to track unabated surge-wave pressure transients. The surge-relief valves can be gas loaded or pilot operated. Both types of surge-relief valves actuate in 100 msec and open in 250 msec, thus diverting the required flow quickly enough to keep the pipeline pressure well below the setpoint. Also in the line and designed for use in demanding isolation applications, the M&J expanding-gate valves provide a bidirectional mechanical seal. The expanding-gate valves use a two-piece gate assembly that expands against the seating areas in the open or closed position. The seal becomes tighter with increasing torque, resulting in reliable, heat-resistant sealing independent of line pressure or vibration. Also, the expanding-gate valves have double block-and-bleed capabilities and seal at low and high line pressure. They are suited for use in applications such as meter bypass, pig launch/receiver traps, hot tap, manifolds, tanks, stations and as mainline block valves.