Thermal Differential Switch
-100° to 392°F, -70° to 200°C
Unit: CRN, CSA
The model T21 point flow switch uses a thermal differential technique to measure liquid or gas flow, level, or interface by sensing changes in the thermal heat transfer characteristics of the media where it is located. The sensor consists of a pair of matched Resistance Temperature Detectors (RTDs) encased in twin 316 series stainless steel tubes. One RTD is self-heated by a constant DC current while the other is unheated, in contact with the liquid, and provides an accurate ambient process temperature. It is adjustable to a specific flow rate.
The T21 is a popular choice for low-flow alarm switching, monitoring lube oil on bearings and gears in rolling mills, and monitoring the flow of cooling water on pump seals.
- Wide operating process flow ranges from -100°F to 392°F
- Removable, plug-in electronics board
- Self-heating sensor design