The Cryogenic Fuels LNG dispenser unit is designed to perform a two-line vent fill with the vent gas being metered and recovered to the facility main bulk storage tank. The dispenser unit includes a density compensation metering subsystem, the pneumatically operated, fuel delivery shutoff valves, a 40 micron filter, two direct mass metering, flow meters, for liquid/vapor totalizing, and a back-pressure regulator that may be preset to provide operating pressures of 50 to 110 psi in the vehicle tank. The dispenser unit also includes an explosion-proof box that contains the start/stop switches, a methane gas detector, hazardous warning lights and the emergency stop button.
The programmable system controller (PLC) for the dispenser is located in a non-hazardous area that must be located at least 70 ft. from the fuel storage and fuel dispensing area. This subsystem consists of the system electronic circuits that transmit the signals from various control components including the pump prime and pump start/stop commands and the signals from the liquid sensors. The station liquid sensors control the plumbing cool-down and the start of the pump motor. Liquid sensors are also installed in the dispenser and the fueling hose disconnect to control re-circulation flow and automatic fuel shut-off when the vehicle tanks are 100 % full.
The Model C-1000-2 dispenser is also equipped with multiple fueling disconnects of different types to accommodate a variety of fuel tank receptacles. The vehicle fill process is initiated by depressing the "fueling start" button on the front of the console. A liquid sensor installed in the dispenser provides the signal to automatically terminate the fueling process when the fuel tank is filled to 90% of its maximum allowable volume. The fill process may also be terminated at any time by depressing an "emergency stop" switch, is also on the front of the dispenser console.