Clamp-on and strap-on RTD sensors measure pipe or tube surface temperature without penetrating the pressure boundary — eliminating the need for isolation valves, hot-tapping, process shutdown, or any modification to the pipe. The sensor is clamped, bolted, or banded to the outside of the pipe and held in firm thermal contact.
A spring-loaded Pt100 element mounted in a stainless steel pipe-clamp body that adjusts to fit pipe OD from 1/2" to 4" NPS. The spring mechanism maintains consistent contact force between the sensing element and the pipe surface across the full temperature range, compensating for thermal expansion. No pipe insulation removal required for standard installation.
A flat Pt100 sensing element bonded to a thermal coupling pad, held against the pipe surface by a stainless steel banding strap. Fits any pipe OD with no adjustment required — the strap wraps and locks. Low profile; compatible with pipe insulation over the top. The lowest-cost non-invasive solution for permanent monitoring installations.
Designed for permanent installation under pipe insulation, the UIR version uses a low-profile stainless housing and MI-insulated lead cable rated for the high ambient temperature environment under lagging. The Pt100 element is encapsulated in thermally conductive compound within the clamp body to maximise thermal contact with the pipe. Widely used for heat tracing monitoring and steam jacketed piping.
| Parameter | RTD-CO-1 | RTD-CO-2 | RTD-CO-3 |
|---|---|---|---|
| Element | Pt100 Class B | Pt100 Class B | Pt100 Class B |
| Wire Config | 3-wire | 2 or 3-wire | 3-wire |
| Pipe Size Range | DN15 to DN100 (½"–4") | Any OD — strap adjustable | DN20 to DN150 |
| Max Process Temp | 350°C | 250°C | 300°C |
| Clamp Body | 316SS machined body | 316SS banding strap | 316SS low-profile body |
| Thermal Pad | Copper contact pad | Thermally conductive silicone | Thermal compound fill |
| Lead | PTFE 3×24 AWG, 36" | PTFE 3×24 AWG, 36" | MIMS 3-core, 36" |
| Accuracy Note | ±2–5°C vs process fluid* | ±3–8°C vs process fluid* | ±2–5°C vs process fluid* |
* Surface measurement accuracy depends on pipe insulation, flow conditions, and ambient temperature. Not a substitute for immersion measurement where accuracy is critical.
Clamp-on sensors measure pipe outer-surface temperature, not process fluid temperature. In well-insulated, fully-developed turbulent flow, the surface temperature closely tracks the fluid temperature. In low-flow, stratified-flow, or poorly-insulated conditions, a surface measurement may be 5–20°C cooler than the process fluid. For accuracy-critical measurements, use an immersion sensor. For leak detection, heat-trace monitoring, flow confirmation, and safety backup measurements, clamp-on RTDs provide a practical and cost-effective solution.
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