A thermal immersion circulator is an electrically powered device that circulates and heats a warm fluid kept at an accurate and stable temperature. It is used in process, environmental, microbiological, hazardous waste, and other laboratories. Since the late twentieth century they have also been used for sous vide food cooking (prolonged cooking of food in sealed packages in a water bath at lower temperatures than usually used for cooking).

A thermal immersion circulator comprises a circulator pump

Circulator pump

A circulator pump is a specific type of pump used to circulate gases, liquids, or slurries in a closed circuit. They are commonly found circulating water in a hydronic heating or cooling system...

 (a mechanism to move the fluid), a heating element

Heating element

A heating element converts electricity into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element....

 immersed in the fluid, an accurate temperature probe

Resistance thermometer

Resistance thermometers, also called resistance temperature detectors or resistive thermal devices , are sensors used to measure temperature by correlating the resistance of the RTD element with temperature. Most RTD elements consist of a length of fine coiled wire wrapped around a ceramic or glass...

, and control circuitry

Process control

Process control is a statistics and engineering discipline that deals with architectures, mechanisms and algorithms for maintaining the output of a specific process within a desired range...

 which compares the measured temperature with the desired value and supplies power to the heater as required to stabilise the temperature.

It has been recommended that second-hand

Second-Hand

Second-Hand was a 2005 Romanian film directed by Dan Piţa.-Plot summary:The film's plot surrounds the romantic involvement of two contrasting characters: Petre , a Mafioso, and Andreea , a young violin player. The pair meet and fall in love...

laboratory circulators should not be used for food, or in a kitchen, due to the risk of contamination, as chemical residues cannot be completely removed.