The Thermatel® Model TD1/TD2 switch is utilized in flow, level and interface applications. The TD1/TD2 is popular for pump protection, specifically low flow detection with the unique spherical tip design, to prevent pumps from running dry. Continuous diagnostics with fault indication, temperature compensation and fast response time make the TD1/TD2 the latest in thermal dispersion technology.
The thermal switches are based on convective heat transfer. One sensor is at the process temperature and the other is being heated by a constant power. As the flow rate increases, the temperature difference between the sensors decreases. A set point is established so when that specific temperature difference is reached the relay changes state. This can be on either increasing or decreasing flow or flow/no flow. When used in a level or interface application it is primarily the thermal conductivity of the fluid that will provide the difference in heat transfer.
Temperature compensated to provide repeatable alarm under varying process temperatures
Continuous diagnostics detect sensor fault
Non-linear mA output signal can be used for trending, diagnostics and repeatable flow/level indication
Detects minimum flow or presence / absence of flow
Excellent low flow sensitivity
Simple calibration / installation
Hot tap retractable probe
Window to view alarm status
Integral or remote electronics
Flow body for very low flow detection