A wellhead safety valve control system for opening and closing subsurface and surface safety valves in a predetermined sequence and certain components used with such control system. Dump valves in both latching and non-latching configurations are utilised within the control system. Safety Valves Embodiments of the dump valve may incorporate a time delay feature to ensure the subsurface safety valve is closed after a desired time period following the closure of the surface safety valve in the event of flowline anomalies. Provision is made for independent closure of the surface safety valve without closure of the subsurface safety valve. Ball Valves Wellhead safety valve control system for opening and closing a surface safety valve (SSV) and a surface controlled subsurface safety valve (SCSSV), said system comprising a first dump valve and a first safety valve circuit operably associated with said surface safety valve,CHECK VALVES a second dump valve and a second safety valve circuit operably associated with said surface controlled subsurface safety valve, an SSV trip control circuit operably associated with said first dump valve, an SCSSV trip control circuit operably associated with said second dump valve, a pump for pumping hydraulic fluid, said pump being operably associated with said first and second safety valve circuits and at least one check valve to operably isolate said SCSSV trip control circuit of said second dump valve from said SSV trip control circuit of said first dump valve.

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