Pipe2012: Gas node elements include junctions, reservoirs, compressors, regulating valves, variable pressure supplies, check valves, valves, metered connections, intermediate nodes, inline meters, and user-defined devices.
Junction - A connection of one (dead end junction) or more pipe links. A junction may be placed at a high or low point in a pipeline to compute results for this location.
Reservoir - A connection of one or more pipe links to a constant level reservoir. During a simulation, the reservoir level remains constant unless data is provided to change its value for a particular simulation or at a specified time.
Variable Pressure Supply - A connection of one or more pipe links to a supply where the supply pressure depends on the supply flow and is determined by using pressure-flow data (either 1) static pressure, residual pressure and flow, or 2) multiple pressure-flow data points). This device is ideal for modeling a connection to a distribution system such as a supply to a subdivision.
Pump(s) - A connection of one or more pipe links to a pump. The pumps characteristics may be defined by constant power, a rated condition, head-flow data, or a pump file which includes data for all zones of operation. Multiple pumps (parallel or series) may also be modeled using the pump element.
Regulator - A connection of one or more pipes is required to each side of the device that maintains downstream pressure (pressure regulating valve), upstream pressure (pressure sustaining valve) or flow (flow control valve).
*Check Valve - Allows flow only in the specified direction. If conditions exist for flow reversal, the valve closes and the line carries no flow. Note: the directional arrow should be in the direction of flow.
*On/Off Valve - A cut-off or isolation valve which can be closed to prevent flow in the pipeline..
*Meters - A metered connection node can be defined at any junction or inserted into a pipe. Each Metered Connection in a model can have several associated meters, each with its own demand, demand type, name, and user data (e.g. address).
* These are intermediate Nodes which do not add to model overhead.