Natural Gas Vehicle Fueling Systems

There are three basic configurations for natural gas fueling stations:

Quick Fill: Used when the vehicle must be fueled in a time period and manner similar to that of liquid fuels. The compressor fills the cascade; from where gas is transferred to the vehicle via the dispenser.
Time Fill: Used when all the vehicles return to a central location, during which time they can be fueled. The compressor fills all the vehicles simultaneously via the hose poles.
Combination: Used when some vehicles return to a central location for fueling, while the balance of the fleet is not centrally garaged, and must be fueled in a short time period. This system combines both of the above features, and is the system depicted opposite. The appropriate configuration is determined by the fueling characteristic of the fleet and customer requirements. While the size and design of the facility may vary, the same basic features are usually incorporated into each system.

The QUICK FILL DISPENSER meters and dispenses gas into the vehicle. A wide variety of dispensers are available, ranging from a simple cabinet with a digital display to a sophisticated microprocessor controlled dispensing system.

The STORAGE CASCADE is used to store gas at a pressure higher than the vehicle storage pressure. This differential pressure is used to transfer the gas from the cascade into the vehicle. Cascades are available comprising of either DOT bottles or ASME vessels, (ASME vessels shown) depending upon the storage capacity required. The system is typically divided into three banks: high, mid, and low. Any number of cascades can be connected together to increase storage capacity.

The PRIORITY/ESD PANEL incorporates two separate systems: the PRIORITY SYSTEM, which is used to divert gas from the compressor to the appropriate component in the fueling system and the EMERGENCY SHUTDOWN (ESD) SYSTEM, which is used to isolate the storage cascade from the quick fill dispenser in the event an ESD button is depressed.

The CHARGER SERIES compressor is a compact, vertical design, water cooled unit, designed specifically for incorporation into small and medium sized NGV fueling facilities.

The GAS DRYER is used to remove water vapor from the gas and to dry it to a pressure dew point which meets local conditions.

The TIME FILL HOSE ASSEMBLIES are used to transfer gas from the compressor/distribution system into the vehicles. They are available in single, dual or four hose versions and are normally unmetered.

For higher flow applications, the horizontal, two throw, balance opposed Century Series Compressor or the single throw, inline, Slimline Series Compressor are recommended. This unit is a balanced-opposed, water cooled unit and is available in both electric motor and engine drive configurations.

The following photographs depict typical NORWALK CNG FUELING STATIONs:

NORWALK CNG FUELING STATION Equipment - Click on photo for larger view: