The Panametrics TransPort PT878GC gas flow meter is a highly versatile, self-contained, portable transit-time system with options and accessories to meet a variety of gas flow measurement needs. It is especially useful for metering erosive, corrosive, toxic, high-purity or sterile gases, or for any application where penetrating the pipe wall is undesirable. Since no tapping or cutting of the pipe is required, installation costs are significantly reduced .

Historically, clamp-on flow metering was limited to liquids because existing methods could not work on metal pipes containing gases. Panametrics developed new technology that extends all the benefits of clamp-on flow metering to gas measurement at high or low pressure in pipes made of metal and most other materials. The transit-time technique uses a pair of transducers, with each transducer sending and receiving coded ultrasonic signals through the fluid. When the fluid is flowing, signal transit time in the downstream direction is shorter than in the upstream direction; the difference between these transit times is proportional to the flow of velocity. The PT878GC measures this time difference and uses programmed parameters to determine flow rate and direction .

The PT878GC measures volumetric flow, flow velocity, and mass flow. It operates from -4 to 131°F (-20 to 55°C) and features a large, 240 x 200 pixel backlit LCD display. The rechargeable battery provides 8 hours of continuous operation. The meter has memory capacity to log over 100,000 flow data points and is housed in a submersible IP67 enclosure. Non-invasive transducers ensure no moving parts and no pressure drop, while sound speed output provides additional diagnostic information .