Multipoint / Multilevel Temperature Sensor

Where a process needs the temperature profile rather than a single value, a multipoint sensor replaces dozens of separate nozzles with one assembly. Catalyst beds in reactors, trays in distillation columns, layers in storage tanks and heat-treatment vessels are all monitored this way, and the profile is what the operator uses to spot hot spots, channelling, stratification or a runaway before a single-point sensor would.

Assemblies carry up to 60 measuring points with RTD (Pt100) elements from −200 to +600 °C or thermocouples of Types K, N, J, E, S and B up to +1,800 °C, in single- or dual-element construction. Insertion lengths follow the vessel drawing and can run to many metres, with internal supports and clamps to hold the elements in position. The thermowell is flanged or threaded and rated up to ASME Class 2500 depending on design, material and temperature; wetted materials include 316, 316L, 321, 310, 347 and 446 stainless steel, Hastelloy and Inconel for high-temperature and corrosive service.

Sensors are wired to a remote or integral junction box, or fitted with multi-input transmitters delivering 4–20 mA, HART, FOUNDATION Fieldbus or PROFIBUS. Accuracy is Class AA, A or B per IEC 60751 for RTDs and the tolerance class per IEC 60584-1 for thermocouples. Safety chambers, thermowells, supports and extension cables complete the assembly.

Multipoint sensors serve chemical, petrochemical, oil and gas, refining and general process plants.