An improved fast-response microthermocouplea)

Abstract

An improved wire-type chromel–alumel microthermocouple with a disk-shaped junction is described. In this design, the 20 μm diameter thermocouple wires are installed taut between two 127 μm diameter prongs, one of chromel and the other of alumel. The disk junction, of 0.1 mm diameter and 4 μm thick, is located approximately midway between the prong tips. Time constants of two microthermocouples are reported. The two microthermocouples differ from each other primarily in the length of the prongs. The microthermocouple with the longer prongs exhibits faster response, its time constant in turbulent flow of liquid Refrigerant-113 (a poor conductor of heat) being less than 2 ms.

Selective Electroless and Electrolytic Deposition of Metal for Applications in Microfluidics: Fabrication of a Microthermocouple

“…Thermocouples are a common tool for measuring temperatures within a specified range very accurately. − Thermocouples and thermopiles have been microfabricated or micromachined previously and have been demonstrated in applications such as thermal radiation sensors, thermal converters, and ac voltage meters. Here, we demonstrate the integration and applications of thermocouples in microfluidics.…”

Manipulation of Lipid Membranes with Thermal Stimuli

“…Local temperature increase caused by the IR-B laser heating on the microscale can be measured by means of various techniques, for example, using microthermocouples [18,19], surface printed thermistors or resistance temperature detectors (RTDs) [20], fluorescence-based techniques using temperature-responsive fluorophores [21], or by ion conductometry through a narrow glass capillary [22]. We have developed two different methods: measurement with a CHCO-005 E-type microthermocouple (wire diameter: 25 μm, Omega Engineering, UK) or by using a thermoresponsive gel, e.g., produced from the lower critical solution temperature (LCST) polymer PNIPAm.…”