9 Automatic Valves-Namely, Automatic Flow Control Valves Used for the Control and Regulation of Flowing Liquids, Gases and Slurries, Multiple Orifice Valves, Gate Valves, Safety Valves, Automatic Shut-Off Valves, Stepping Actuator Control for Multiple Orifice Valves, Block and Bleed Valves, and Pig Ball Injector and Receiver Valves, Used to Introduce into and Recover from Fluid-Conducting Flow Lines, Objects Forced Therethrough for Cleaning the Walls of the Line