Product Description

Master-Touch™ products include a rugged, cleanable, thermal mass flow sensor. These units consist of a sensor assembly which utilizes two RTD (Resistance Temperature Detector) sensing elements. The sensors are constructed of reference grade platinum, ceramic, glass, and stainless steel. Two platinum resistance sensors are built up upon the ceramic substrate and then given a thin glass coating. The assembly is then slipped into a stainless-steel sheath for corrosion and abrasion resistance. The sensor assembly is large, rugged, and relatively insensitive to dirt buildup. During operation, the temperature sensor constantly measures the ambient temperature of the gas and maintains a reference resistance on one side of a bridge circuit. The second sensor is forced through self-heating to a constant temperature above that of the gas stream and is controlled by the temperature sensor and bridge circuitry. Our bridge maintains the overheat temperature and counterbalances the temperature effects through our proprietary temperature compensation techniques.

9200 Series flow meters are approved for use in hazardous locations (see specifications).

Insertion style thermal mass flow meters 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 1/2″, 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.

Remote style thermal mass flow meters utilize two enclosures. One enclosure is mounted at the point of measurement on the probe assembly. This enclosure is rated for hazardous environments. The second (remote) enclosure is usually placed in a readily accessible location rated for non-hazardous conditions. (Contact the factory for information concerning remote explosion-proof enclosure). The remote enclosure includes all the electrical connections as well as the linearizing electronics and the display/keypad assembly. A 5-conductor shielded cable is required to carry the flow signal between the two enclosures.

Our patented Flow Averaging Tubes™ (FAT™) use the principle of convective heat transfer to directly measure mass flow and are well suited to most applications with limited available straight run. In many installations, the up-stream straight run can be reduced to three diameters. The probe has several large diameter inlet ports along the length of the upstream impact surface. The pressure at each inlet port is averaged inside the tube to create the axial flow through the tube and across our flow sensor. The gas returns to the main flow stream through the ports located near the sensing elements. Anomalies in the actual flow profile or installations in non-circular ducts may still some require minor adjustment to achieve the best accuracy.