SIGMA VALVES

automatic valves for use in pneumatic and hydraulic control systems and oil and gas wells, namely, pressure controlled fluid operated valves, manual reset relay valves, automatic reset relay valves, reservoir vent valves, pneumatic quick exhaust valves, hydraulic quick exhaust valves, pneumatic check valves, hydraulic check valves, fusible plugs, fusible valves, fuel cutoff valves, emergency shutdown valves, manual operated valves, pilot operated relay valves, pump shut off valves, hydraulic interface controller valves, hydraulic accumulators, pressure sensing pilot valves, pressure indicators, pumps, wellhead control systems, pressure manifolds fixed orifices, 2-way valves, 3-way valves, erosion sensor valves, pneumatic relief valves, hydraulic relief valves, and pressure regulator valves