Dwyer Instruments' Series TDT Thermal Dispersion Flow Transmitter delivers accuracy over a range of pipe sizes
The W.E Anderson Division of Dwyer Instruments introduces its Series TDT Thermal Dispersion Flow Transmitter. Series TDT is an alternative to turbine and paddlewheel insertion flow meters, designed with the ability to deliver accuracy over a range of pipe sizes. These units have the same insertion mounting into a 1-1/2-inch NPT, but are designed without any moving parts to wear, break or clog. The TDT Dispersion Transmitter is engineered to measure low flow rates and can be used for the metering of all fluid media. Due to the adjustable insertion mounting, one model is suitable for pipe sizes of 1 to 24 inches, and with available extensions, it can be used for pipes sized up to 75 inches in diameter. Series TDT is also available in titanium, as well as an optional temperature output.
The Series TDT operates with the use of a sensor head that contains two PT-resistors. One of these measures the temperature of the media, while the other is heated by an attached heating resistor. The temperature difference between the two PT-resistors is predetermined and a control circuit keeps this temperature difference constant. The flow of the media cools the heated PT-resistor proportional to the speed of the flow, which results in a linear output signal proportional to the flow speed.
Available flow range options include: 0 to 1.64 ft/s (0 to 0.5 m/s), 0 to 3.28 ft/s (0 to 1 m/s), 0 to 6.56 ft/s (0 to 2 m/s), 0 to 9.84 ft/s (0 to 3 m/s) and 0 to 12.47 ft/s (0 to 3.8 m/s).