Liquid volumetric flow rate applies only to those rotameters that are liquid volumetric flow sensors or meters. It is expressed as the range of flow in volume/time. Gas volumetric flow rate applies only to those rotameters that are gas volumetric flow sensors or meters. It is the range of flow in volume/time. The operating pressure is the maximum head pressure of the process media the meter can withstand. The maximum temperature of the media that can be monitored is usually dependent on construction and liner materials.
Pipe diameter is also important to consider, especially when specifying specific mounting options. Mounting options for rotameters include insertion types, in-line flanged, in-line threaded, and in-line clamp. Insertion flow meters are inserted perpendicular to flow path. They usually require a threaded hole in the process pipe or other means of access. In-line flanged flow meters are inserted parallel to the flow path, usually inserted between two pieces of existing flanged process pipes. In-line threaded flow meters are inserted parallel to the flow path, and threaded into two existing process pipes. NPT is the most common thread type. In-line clamp flow meters are inserted parallel to the flow path, and clamped between two existing process pipes.