Insertion style Thermal Mass Meter include a sensor & probe assembly that is inserted into the process gas flow conduit to allow the process gas to flow across the flow sensing elements. Our insertion style flow meters are available with 3/4″, or 1″ OD probes. Tube fittings and ball valve retractor assemblies, with or without a mounting flange, are also available from the factory as options. The tube length must be specified upon ordering. For other probe diameters and lengths, please consult the factory.
Integral style Thermal Mass Meter have all of the electrical components and connections located within one enclosure. The enclosure is mounted directly to the insertion probe assembly at the point of measurement. The enclosure includes the all of the electrical connections as well as the linearizing electronics and the display/keypad assembly.
Thermal mass meter use the principle of convective heat transfer to directly measure mass flow. ProFlow’s proprietary thermal mass flow sensors use two ratiometrically-matched, reference-grade platinum Resistance Temperature Detectors (RTDs). The platinum sensing element wire is encapsulated in a 316 Stainless Steel sheath or, if specified, a Hastelloy C sheath. Our microcontroller operated smart sensor technology preferentially heats one RTD; the other RTD acts as the temperature reference. The process gas flow dissipates heat from the first RTD, causing an increase in the power required to maintain a balance between the RTDs. This increase is directly related to the gas molecular rate of flow. Our sensors are temperature compensated for a wide process gas temperature range and insensitive to pressure changes, so the output signal is a true mass flow rate signal.