9 Automatically Operated Fluid Flow Control Valves for Surface and Sub-Surface Devices for Oil and Gas Production, and for Valve Control Devices-Namely, High and Low Pressure Sensing Pilot Valves, Pilot Relay Valves to Bleed Off Pressure from an Actuator Valve or Pneumatic System, Valves to Detour Flow, and Indicating Relay Valves to Indicate the First Component of a System in which a Malfunction Occurs